Cooling performance of nanofluid submerged vs. nanofluid circulated battery thermal management systems

Journal Pre-proof Cooling Performance of Nanofluid submerged vs. Nanofluid Circulated Battery Thermal Management Systems

R.D. Jilte, Ravinder Kumar, Mohammad H. Ahmadi PII:

S0959-6526(19)33001-X

DOI:

https://doi.org/10.1016/j.jclepro.2019.118131

Article Number:

118131

Reference:

JCLP 118131

To appear in:

Journal of Cleaner Production

Received Date:

04 May 2019

Accepted Date:

21 August 2019

Please cite this article as: R.D. Jilte, Ravinder Kumar, Mohammad H. Ahmadi, Cooling Performance of Nanofluid submerged vs. Nanofluid Circulated Battery Thermal Management Systems, Journal of Cleaner Production (2019), https://doi.org/10.1016/j.jclepro.2019.118131

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

Journal Pre-proof

Cooling Performance of Nanofluid submerged vs. Nanofluid Circulated Battery Thermal Management Systems R. D. Jilte1, Ravinder Kumar1, Mohammad H. Ahmadi2*

1School

of Mechanical Engineering, Lovely Professional University, Punjab, India

2Faculty

of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran

* [email protected];[email protected] (M.H. Ahmadi)

1

Journal Pre-proof Abstract For a cleaner environment, the production of fossil fuel propelled transport vehicles need to reduce. Technological advances are aimed to manufacture cost-effective battery electric vehicles compared with the conventional one. An efficient battery cooling system is necessary for safer usage of electric cars during their life cycle. This paper presents two ways of arranging cooling components: liquid filled battery cooling systems (LfBS) and liquid circulated battery cooling systems (LcBS). The air conditioning unit of an electric vehicle has integrated with the battery cooling unit. Cooling performance of LfBS and LcBS arrangements presented for both water and nanofluid as cooling media at 2C and 4C discharge rates. The air required for LfBS cooling or LcBS cooling has supplied at two supply conditions: first, if the ambient temperature is around 35°C and air-conditioning is ‘OFF’ in an electric vehicle. Second, air-conditioning is ‘ON’ and recirculated air from car cabin is available at 30°C to supply it to the battery cooling system. The result shows the applicability of such battery systems for the safe operation of electric vehicles.

Keywords: Battery cooling, Liquid filled battery module, Liquid circulated battery module, nanofluids, cooling performance

2

Journal Pre-proof Nomenclature Cp K Re Pr Kbz d T M N Ra T* R* Tcell ∆T

Specific heat (J/kgK) Thermal conductivity (W/mK) Reynold number Prandtl number Boltzmann constant (J/K) Diameter (m) Temperature (°C) Molecular weight of water Avogadro number Rayleigh number Nondimensional temperature Nondimensional radial distance Cell temperature (°C) Maximum cell temperature difference (°C)

Greek symbols μ ρ ϕ

Dynamic viscosity (kg/ms) Density (kg/m3) Nanoparticle volume fraction

Subscripts bf nf p eff i o a fr

Base fluid Nanofluid Nanoparticle effective Inner Outer Ambient freezing

Abbreviations BTMS LfBS LcBS C DoD

Battery thermal management system Liquid filled BTMS Liquid circulated BTMS Discharge rate Depth of discharge

3

Journal Pre-proof 1. Introduction Due to the limited reserves of fossil fuels and environmental concern, the research prioritizes on new and renewable energy sources to fulfill the energy requirement for sustainable growth of the society. Such new energy conversion routes also demand energy storage in the form of electrochemical batteries. Applications like automotive, military, aerospace, medical, etc. use batteries as an energy storage source. In a step, electric vehicles could overcome the shortage of fossil fuels and reduce pollution in the city since the energy needed and stored in electrochemical batteries can be generated from clean sources such as solar, wind energy, etc. The overall design of electric vehicle battery pack involves selection steps like battery type, cell packaging, battery management system, battery thermal management system, etc. (Saw et al., 2016a). More precisely, the value chain of electric vehicle batteries typically comprised of seven steps (fig 1): component production, cell production, module production, battery pack assembly, vehicle integration, use during the life of the vehicle and lastly processing of discarded batteries for reuse and recycling(BCG, 2010).

Figure 1 The value chain for electric vehicle batteries(BCG, 2010)

4

Journal Pre-proof It is estimated that around 2022, cost of battery electric vehicle will be comparable with that of the conventional car driven by the internal combustion engine and market share in total automobile market would reach to 10% by 2024(Deloitte, n.d.). Few rechargeable batteries available commercially are lead-acid, nickel metal hydride, nickel cadmium, and lithium-ion. Among these, lithium-ion batteries have shown several advantages. -

It has a low value of self-discharge and can be charged rapidly to maintain the dynamism of electric vehicles(Khan et al., 2017).

-

Lithium-ion batteries have very high specific energy per weight as necessary in automotive applications(Bandhauer et al., 2014)

-

Lithium-ion batteries are less toxic as compared to their counterpart enabling few disposal problems.

-

It has a long cycle life with high open circuit voltage.

Therefore electric vehicles are preferred with Li-ion batteries although batteries majorly contribute to electric vehicle’s life cycle environmental impacts(Marques et al., 2019). Many conceptual studies have been carried out(Hu et al., 2012; Waag and Sauer, 2013). Electric vehicle needs a large battery with high current discharge and expected to charge rapidly. Battery undergoes various electrochemical reactions intensified further during conditions like quick acceleration due to high current discharge(Lin et al., 1995; Selman et al., 2001; Williford et al., 2009). Among the several factors that affect battery life, battery temperature attained during its operation is significant(Panchal et al., 2016). The battery temperature further becomes crucial for batteries running with higher discharge rate(Wang et al., 2015)(Zhang et al., 2018). In Electric vehicles, regenerative breaking causes internal heating of battery(Kim et al., 2013). The safe operating temperature range for Lithium-ion batteries are within 20°C to

5

Journal Pre-proof 40°C. The non-uniformity in battery temperatures significantly affect the performance of the battery module too and responsible for short circuit and local degradation due to hot spots. The battery reaction rates increase exponentially with the rise in cell temperatures. Cells attaining higher temperature degrade at a faster rate as compared to their counterpart cells with lower temperature(Mahamud and Park, 2011). Lithium-ion battery life reduces almost by 60 days per degree temperature rise in an operational temperature of 30°C to 40°C(Hallaj and Selman, 2000). Therefore Li-ion battery modules temperature and maximum temperature non-uniformity are required to be maintained under 40 °C and 5°C respectively(Mahamud and Park, 2011). Considering the thermal aspects of battery operation; there are two factors (safe cell temperature and cell temperature uniformity) essential in developing cooling strategies for batteries. An increase in cell temperature above critical threshold value tends to degrade the electrolyte solution reducing its performance and cell life performance(Rao and Wang, 2011). It further reported that excess heat produced during battery charging or discharging if not dissipated effectively, create thermal runaway condition and may even lead to a fire(Lisbona and Snee, 2011). Due to higher cell temperature, capacity fade, and power reduction is a common occurrence. The battery cell temperature attained during the charging/discharging cycle can be controlled and kept below a safe limit with the help of battery thermal management system [BTMS]. Several studies have reported on BTMS exploring heat dissipation or cooling performance using air, liquid or Phase change material as the cooling media. Among these, air-cooled BTMS is lightweight and simplest. (Wu et al., 2002) showed that the battery system adopting natural convection based cooling is not sufficient for dissipating heat from battery systems. The forced convection based cooling system reduces it. (Giuliano et al., 2012) presented the cooling of lithium titanate batteries with air-cooled BTMS for electric vehicles. (Fan et al., 2013) in their numerical work proposed two-side cooling is better

6

Journal Pre-proof compared to one-side cooling for the same gap spacing and air flow rate. (Park and Jung, 2013) analyzed the air-cooled system with a liquid-cooled one. Air-cooled BTMS with more arrays of cells requires excessive cooling air flow rate and consumes more power, although the air-cooled system is simple in design, lower in cost, easier for maintenance and shorter warm-up period. There is an optimal placement of cells in a pack for balancing between cellcell distance and wall-cell distance. Higher wall–cell distance in an air-cooled BTMS for reducing temperature rise results in a more sizeable overall packing, and also a requirement of higher air flow rate (He et al., 2014). If the intercell distance is less, higher air flow is required for adequate cooling and increases its cost and size of the pack(Wang et al., 2014). Performance comparison between the aligned and the staggered battery cell arrangement in an air-cooled BTMS shows better cooling efficiency and temperature uniformity in an aligned one(Yang et al., 2015). (Mahamud and Park, 2011) used reciprocating air flow to reduce maximum cell temperature and temperature non-uniformity. (Sun et al., 2012) indicated that cooling duct geometry adopted in BTMS could alter temperature uniformity. Panchal et al., 2016a estimated that at increased discharge rates, the principal surface of the battery show increased surface temperature distributions. The certain BTMS performing satisfactorily at lower discharge rate with air may need to alter concerning powerful tangential blower arrangement or liquid cooling for safe operation at higher discharge rates(Saw et al., 2016b). The use of air as cooling media in BTMS, especially for high discharge rate may not function satisfactorily(Rao and Wang, 2011). Although the battery system cooled with forced convection air cooling mitigate temperature rise in the cell, it faces the difficulty of cooling it below 52°C if the temperature rises higher than 66°C(Nelson et al., 2002). Specifically, at stressful battery operating conditions in terms of either higher ambient temperature(>40° C) and higher discharge rates, air cooling demands significant fan power and not effective in

7

Journal Pre-proof maintaining desirable operating conditions(Sabbah et al., 2008). The battery system can also be cooled with liquid cooling media such as mineral oil, water, dielectric fluid, ethylene glycol, etc. As expected, liquid cooling is more heat dissipation efficient as compared to air cooling(Nelson et al., 2002). It is insensitive to the placement inside the vehicle(Rao and Wang, 2011). Liquid cooling systems increase vehicle weight and cost, whereas air-based cooling is less complicated. (Pendergast et al., 2011)

housed cells inside a triangular

aluminum module, then put them under water. Comparative study between air cooling and silicone transformer fluid carried out by (Nelson et al., 2002) showed that a system employing transformer fluid is better for dissipating heat from the cells. (Giuliano et al., 2012) reported that heat generation in a liquid cooled BTMS is higher in a region closer to cell terminals. (Jarrett and Kim, 2011) suggested that the channel width in the liquid-cooled system should be wider to lower average temperature of the channel. (Jin et al., 2014) compared oblique mini-channel and conventional straight mini-channel as a cooling arrangement for Li-ion batteries and found that oblique mini-channel enhances heat transfer coefficient. Effects of channels, flow direction, ambient temperature, inlet mass flow rate using the mini-channel cold plate in prismatic batteries have analyzed by (Huo et al., 2015). Different ambient temperature conditions, cooling methods should be modified.

Under normal ambient temperature

conditions, liquid cooling produces the highest cooling. (Zhao et al., 2015) presented minichannel liquid cooling for cylindrical batteries and found that the mass flow rate limits a decrease in maximum temperature rise. The base fluid used in liquid-cooled battery systems suffers from a low value of thermal conductivity. The heat dissipation is associated with convective heat transfer from battery surfaces and which can be increased passively by changing flow geometry or by enhancing the thermal conductivity of the fluid. Researchers have tried to increase the

8

Journal Pre-proof thermal conductivity of base fluids by suspending nano-sized solid particles. Fluids with suspended nanoparticles are called nanofluids. Several studies have been carried out citing nanofluid usage in heat transfer enhancement; among these Choi et al(Choi et al., 2001) introduced the concept of nanofluid and presented that thermal conductivity of base fluid can increase with the addition of nanoparticles of sizes lesser than 100 nm(Duangthongsuk and Wongwises, 2010). (Mondal et al., 2017) explored the efficacy of nanofluids for cooling of lithium-ion prismatic cells. Two types of nanoparticles Al2O3 and CuO have used in pure H2O and EG-H2O solution. A similar study of nanofluid cooling of a cylindrical 18650 lithium-ion cell by submerging it into a cylindrical container carried out by (Sefidan et al., 2017). In this type of arrangement, there is no circulation of nanofluid in a battery cooling system. The heat transfer analysis is carried out by employing air flow on the exterior surfaces of the container for water-Al2O3 nanofluids. (Tran et al., 2017) presented a design for a nanofluid cooled system of lithium-ion batteries used for a zero gravity environment. The suspension of carbon nanotubes in distilled water was used to produce nanofluid. The battery heat was dissipated to nanofluids in an enclosure which then pumped into the radiator for its recirculation. (M F H Rani et al., 2017) in their study on hybrid interface cooling system presented two arrangement of battery thermal management systems using air ventilation using refrigerant (R-134a and R-410a) and two types of nanofluid, i.e., CuO + Water and Al2O3 + Water. The hybrid interface cooling is found more efficient than the conventional one. (Li et al., 2015) used TiO2, ZnO and diamond nanofluids as coolants for tractive Li-ion batteries pack and found that nanofluids perform better cooling as compared to base fluid especially diamond nanofluids is more efficient than that of TiO2 and ZnO nanofluids. (Hung et al., 2013) carried out a feasibility study on the cooling of green power sources (Li-ion batteries, supercapacitors) with nanofluid (Al2O3+Water) in an air-cooled heat exchanger.

9

Journal Pre-proof

In summary, findings can be listed as: -

Liquid cooled BTMS is more effective for adverse battery operating conditions.

-

Most of the BTMS employed with liquid cooling primarily focus on prismatic battery wherein mini channel liquid plates are used.

-

Few studies are carried out to explore the usage of nanofluids for battery cooling.

-

There are limited data available on single cylindrical batteries immersed in liquids along with forced air cooling on container surfaces or an array of cylindrical batteries.

The motivation for the present work were derived from limiting data in a above-stated conditions. (1) The present work provide feasible liquid cooled battery management system suitalble for electric vehicles employed with 18650 type cylindrical cells. The study is useful in other cells like 14500, 14650, 26650, 38120, 38140, 40152, 42120, 63219,76306 etc. (2) The novelty of the study lies in modular cooling with emphasis on cell-to-cell liquid cooling that facilitate cell-to-cell heat dissipation and avoid localized heat spots detrimental to the safe operating condition of a specific cell. (3) The BTMS is modified to allow modular kind of battery packs arrangement embodied with minichannels. (4) It envisage cooling arrangments based on their usage and geographical conditions. Electric vehicle’s battery cooling system can be cost effective by minimizing their components targeted seperatly for colder climate and hot climate countries. (5) Two alternate way of utilizing cooling systems are discussed. In the first arrangement, feasibility studies are presented to eliminate the parasitic power required for the typical case of liquid circulation. Battery cells immersed in a liquid filled container and subjected to convective cooling with coolant air. In the second case, batteries were put in a 10

Journal Pre-proof modified container wherein cooling liquid are circulated, removing heat from it. (6) Study is primarily focus on its cooling performance with base fluid (for example water) and further possible improvement in cooling by adding nanoparticles in base fluid. (7) The study proposed a suitable flow diagram for both the arrangement utilizing ambient air and recirculated cabin air.

2.

Liquid cooled battery thermal management system 2.1

Battery module details

For choosing a battery type, several factors were considered, such as packing design, cost, and production. Small cells have advantageous over large cells due to the lower price with mature fabrication technology(G-H Kim, 2009). The metal casing in cylindrical and prismatic cell helps in maintaining stable structures for components, handling vibration, and withstanding built-up pressure. The vent allows the safer release of gas generation in cells. The prismatic and pouch cells are subjected to poor uniform contact due to lower compressive force on the electrodes while jelly roll design of cylindrical cell provides uniform distribution of pressure on the cell electrode stacks(van Schalkwijk and Scrosati, 2002). The production rate of such cylindrical cells is higher due to easier spiral windings. In the present work, the small cylindrical cells are preferred due to their higher heat dissipation rate based on comparable surface area per unit volume(Kim et al., 2007). For example, 18650 cell (diameter of 18 mm and height 65 mm) gives 222.22 m-1 heat transfer areas per unit volume. In 76306 cell, the ratio of heat transfer area to volume reduces to 52.63 m-1. The packing density (cells per unit volume) is another factor that favors small cylindrical cells. For instance, the packing density of the 168650 and 26650 cells are about 47524 and 22857, respectively. Two types of arrangement are investigated: Liquid filled BTMS (LfBS), and Liquid circulated BTMS (LcBS). In both cases, a module comprised of seven cylindrical 18640 11

Journal Pre-proof cells. In the first arrangement, cells are immersed in a liquid filled container (Fig 2); while in the second case, cells are placed in a container allowing inflow and outflow of fluids (Fig 3). The cell indexing 1-7 (cell#1 being at the inlet, cell#4 at the middle and cell#7 at the outlet of the module) is used to monitor its temperature during battery usage. In LfBS arrangement, heat collected in the container is allowed to dissipate to ambient air or re-circulated air from car cabin. Cells have space for liquid circulation and not directly rested on the base wall of the container and. Similarly, the cell top surface and container top wall allow spacing for liquid distribution.

Figure 2 BTMS proposed with Liquid filled provision (LfBS)

In LcBS arrangement, the heat generated by the battery during its discharging operation is allowed to dissipate to circulating liquid. Here LfBS is modified keeping module arrangement unchanged except the provision for inlet and outlet (Fig 3).

12

Journal Pre-proof

Figure 3 BTMS proposed with the Liquid circulated arrangement (LcBS)

2.2

Nanofluid

The fluid considered here is a water-based nanofluid containing Alumina (Al2O3) 40 nm diameter nanoparticles. The specifications are listed in Table 1. The use of nanoparticles alters the properties of the base fluid. The simulation of nanofluid-employed BTMS necessitates complete thermophysical properties such as density, thermal conductivity, specific heat, and viscosity before their usage. There are several reports available for determining these properties which shown validation with experimental values. Density: The conventional solid-liquid mixture model(Pak and Cho, 1998)(Khanafer and Vafai, 2011) are used for computing nanofluid density as given below: 𝜌𝑛𝑓 = (1 ― ∅)𝜌𝑏𝑓 +∅𝜌𝑝

(1)

where ∅ refers to the volume concentration of nanoparticles and the subscript nf, bf and p denote the nanofluid, base fluid (water) and nanoparticles (Al2O3) respectively. 13

Journal Pre-proof

Specific heat: The specific heat is calculated based on heat capacity concept (Xuan and Roetzel, 2000). (𝜌𝐶𝑝)𝑛𝑓 = (1 ― ∅)(𝜌𝐶𝑝)𝑏𝑓 +∅(𝜌𝐶𝑝)𝑝

(2)

Thermal conductivity: Various experimental and theoretical studies are available for evaluating the thermal conductivity of nanofluids. Present work adopted the correlation proposed by (Corcione, 2011) for estimating the thermal conductivity of water-Al2O3 nanofluids.

𝐾𝑒𝑓𝑓 𝐾𝑏𝑓

0.4

= 1 + 4.4𝑅𝑒𝑝 𝑃𝑟𝑏𝑓0.66

𝑇 10 𝐾𝑝 10 0.66 ∅ 𝑇𝑓𝑟 𝐾𝑛𝑓

( ) ( )

(3)

where Kbf is the thermal conductivity of base fluid (water),Tfr is freezing point of the water. Rep and Pr represent nanoparticle Reynold number and base fluid Prandtl number. Rep is given by: 𝑅𝑒𝑝 =

2𝜌𝑏𝑓𝐾𝑏𝑧 𝑇

(4)

𝜋𝜇𝑏𝑓2𝑑𝑝

where ρbf and µbf represent base fluid density and viscosity. Kbz denotes Boltmann constant (Kbz = 1.38066×10-23 J/K). The nanoparticle diameter dp is taken as 40 nm.

Dynamic viscosity: The correlation proposed by (Corcione, 2011) is used to calculate the dynamic viscosity of nanofluids. 𝜇𝑛𝑓 𝜇𝑏𝑓

=

1

( )

1 ― 34.87

𝑑𝑝 𝑑𝑏𝑓

(5)

―0.3

∅1.03

14

Journal Pre-proof

dbf is the effective diameter of base fluid molecule computed by the following equation: 1

[

𝑑𝑏𝑓 = 0.1

]

6𝑀 𝑁𝜋𝜌𝑏𝑓

3

(6)

where M denotes the molecular weight of water and N = 6.022×1023 mol-1 (Avogadro number). Table 1 shows the thermophysical properties of base fluid, nanoparticles and nanofluids. Table 1. Thermophysical properties

(kg/m3),

Density ρbf Specific heat (J/kgK), Cpbf Thermal conductivity (W/mK), Kbf Viscosity (kg/ms), µbf

Pure water(Incropera et al., 2011) 300C 350C 995.81 993.83 4178 4178 0.6172 0.6248 0.0008034 0.0007246

Alumina (Al2O3) 3970 765 40 -

Nanofluid Φ = 0.4% 300C 1007.71 4124.21 0.6349 0.000934

350C 1005.73 4124.11 0.6461 0.000843

3. Numerical scheme and validation 3.1 Validation for liquid filled case Experimental work by (T. H. Kuehn and R. J.Goldstein, 1976) is used to validate the numerical scheme for the liquid filled case. The set up is made using concentric cylinders allowing water or air in the annular space. Both cylinders are of equal length (203 mm) and made from copper material. The wall thickness of the inner cylinder is 5.1mm and with an outer diameter of 35.6 mm. The inside diameter of the outer cylinder is 92.5 mm with a wall thickness of 4.5 mm. Electric power was provided to the inner-cylinder resistor by a regulated DC power supply. Fig 4 shows a typical arrangement with the terminology used for analysis.

15

Journal Pre-proof

Figure 4 Experimental (T. H. Kuehn and R. J.Goldstein, 1976) annular flow arrangement with data extraction sections Here Ti refers to hot temperature maintained at the inner cylinder wall whereas To is the cooling temperature outer cylinder. Here Ti and To were kept at a respective isothermal temperature of 28.1°C and 27.2°C yielding Rayleigh number in the range of 9.52×104 and Prandtl number of 6.21. For validation purpose, the two-dimensional model is created using Gambit modeling tool. Numerical simulations are carried out with CFD package Fluent 6.3.1 with prescribed boundary conditions. Figure 5 shows a comparison of experimental interferogram and numerically obtained contours of temperature and isotherms. It is in good agreement with that of experimental temperature pattern.

Further comparison of temperature distribution is

recorded along six radial lines (0° to 180°) as shown in Fig 4. These temperature values are converted to non-dimensionless temperature (T*) and plotted against non-dimensional radial distance along each line in Fig 6. It can be seen that numerical results are well matched with the experimental data.

𝑇 ― 𝑇𝑜

𝑇 ∗ = 𝑇𝑖 ― 𝑇𝑜

16

(6)

Journal Pre-proof

𝑅 ― 𝑅𝑖

𝑅 ∗ = 𝑅𝑜 ― 𝑅𝑖

(7)

Figure 5 (a) Experimental interferogram taken using water for RaL = 9.52×104, Pr = 6.21, L/Di = 0.8, (b) Present numerical scheme temperature contours, (c) Numerical isotherms

17

Journal Pre-proof

Figure 6 comparision of dimensionless radial temperature distribution for RaL = 9.52×104, Pr = 6.21

4.2 Validation for liquid circulated case The validation of the numerical scheme adopted in the present study was carried out based on experimental data by (Jafarimoghaddam et al., 2017). They have presented findings on convective heat transfer for nanofluid flow in a concentric annular tube. The test section contains two copper tubes. The inner diameter of the outer tube and the inner tube was 25.4 mm and 6.35 mm, respectively. The wall thickness of the inner tube and the outer tube was 1 mm and 1.3 mm, respectively. Length of both pipes under testing condition was taken 1500 mm. The set up was heated with an electrical coil wrapped on the outer tube. During the experiment, the heating coil was linked to AC power supply at a constant value of 204 W. The set-up was integrated with sensors for measuring wall temperature at 9 locations along the axial length of the tube and nanofluid temperature at inlet and exit of the test section. The experiments were carried out on Al-oil based nanofluids. The thermophysical properties of 18

Journal Pre-proof nanofluid such as thermal conductivity, density, specific heat, and viscosity were determined experimentally before its usage in the set-up. In the numerical scheme, three-dimensional geometry analogous to the dimensions described earlier is created using GAMBIT tool of CFD software package(Fluent 6 Documentation , 2006. Fluent Inc., Lebanon, n.d.). The thermophysical properties of Al-oil nanofluid are referred to measured values. Boundary conditions used during simulation are listed in Table 2. The numerically obtained Nusselt number shows good aggrement with the experimental data(fig 7). Table 2 Boundary condition for simulation Parameter Annulus inlet Annulus outlet Wall of outer tube Other walls

Boundary condition Mass flow rate corresponding to Re = 38.6 to 159 Pressure outlet Constant heat flux corresponds to 204 W No-slip condition

Figure 7 Validation with experimental work (Jafarimoghaddam et al., 2017) 19

Journal Pre-proof

4.3 Mesh sensivity analysis The heat generated in the cell during the discharging condition is due to electrochemical reactions. Details of the battery heat generation model adopted in the current work can be found in our earlier work (Jilte and Kumar, 2018)(Jilte et al., 2019). For ensuring accurate numerical results, a grid independence study has been carried out. In the present case, the geometry was modeled to different mesh sizes (97263, 153287, 172749, and 351223 elements). The battery cells were exposed to 35°C ambient temperature and allowed to discharge at constant amperage of 10A. The water was circulated at a flow rate of 0.01 kg/s. The temperature change at module outlet temperature was monitored since it is influenced by both heat generated in the module and heat convected by water. The computational results are shown in fig 8. It can see that solutions are grid independent after refining mesh. Therefore mesh of elements size 172749 was adopted to avoid the long computational time and solution instability. 35.5

Water outlet temperature (0C)

35.45 35.4 35.35 35.3 35.25 35.2 35.15 35.1 35.05 35 5.00E+04

2.50E+05

Number of mesh elements

Figure 8 Mesh independence study

20

4.50E+05

Journal Pre-proof

5 Results and discussion The battery module was subjected to different operating conditions, and their performance data analyzed for two discharge rates at 2C and 4C. A C-rate is a measure of the rate at which a battery is discharged relative to its maximum capacity. A 1C rate means the battery can last up to 1 hour while constantly discharging at rated current. During the start-up process of the battery, the entire module was subjected to atmospheric condition. Therefore depending on the ambient conditions, the battery module temperature is initialized. In LfBS arrangement, heat dissipated from the battery is convected to nanofluid. Since the battery is enclosed within a container, the removal of heat from nanofluids necessitates external cooling of the container by employing forced air flow. The air required for LfBS cooling (fig 2) or LcBS cooling (fig 3) is supplied at two inlet conditions: first, if the ambient temperature is around 35°C and air-conditioning is ‘OFF’ in an electric vehicle. Second, air-conditioning is ‘ON’ and re-circulated air from car cabin is available at 30°C to supply it to the battery cooling system. It is a reasonable value considering the cabin cooling load with negligible infiltration air. During a simulation, appropriate convective wall boundary condition was applied on the container surfaces. The computational results are presented in terms of transient thermal response of battery module, and temperature field within the module for both scenarios of embedding battery module in a liquid filled container and providing an arrangement for circulating cooling liquid. 5.1 Thermal response of the module Transient responses of cells are studied up to 100 % of the discharge for both water cooled and nanofluid cooled arrangement. LfBS: 21

Journal Pre-proof Figure 9 shows a sample plot of cell#4 temperature of LfBS at both C-rates. Transient response of a cell at the beginning of its operation (0% depth of discharge) equal to air supply/ambient temperature as discussed earlier. It is observed that cell temperature rises steadily during its discharging process. Cell temperature attainment during its usage is affected by cooling liquid. Heat dissipation from the module enclosure wall also depends on prevailing external convective cooling condition. In the present case battery module is placed in a liquid filled container. Therefore, heat transfer from battery surfaces to this liquid is governed by buoyancy-driven flow. The outer container surface dissipates heat to ambient/supplied condition air. Typically, the cell temperature is found higher for waterbased BTMS. Cell temperature attainment can be lowered with nanofluids as seen in Fig 9. This is due to the enhanced cooling of cell surfaces with nanofluids throughout its discharging. Heat dissipation from the module enclosure wall also depends on subsequent ambient. supplied condition air. Heat generation in a cell depends on its local instantaneous cell material temperature. The maximum cell#4 temperature is observed 40.66°C and 39.69°C at Ta = 30°C and 2C-rate respectively for water and nanofluid. These values are within 42.85°C and 41.90°C at Ta = 35°C and 2C-rate respectively for water and nanofluid. Similarly, cell#4 transient response at 4C-rate is also shown in Fig. 9. Although cell temperature rises due to higher discharge rate, the lower cell temperature is reported for nanofluid embedded battery cooling as compared to water embedded battery cooling unit. The maximum temperature is restricted to 45.4°C for the nanofluid case at Ta = 35°C and 4C-rate.

22

Journal Pre-proof

Figure 9. Cell#4 transient response for LfBS LcBS:

In the modified arrangement, the liquid is circulated through a spacing formed between battery surfaces and container walls. The inflow and outflow of cooling liquid are allowed as shown in fig 3. The liquid flow rate of 0.01 kg/s was kept constant. The obtained transient behaviors are plotted in fig.10 for both 2C and 4C-rate at a liquid inlet temperature of 30°C. It can be seen that maximum temperature developed in battery module is very less as compared to liquid embeded cooling system described earlier. The significant cell temperature rise is observed during initial period of battery discharging (up to 12% of depth of discharge).

It can be shown that cell temperature attainment during its complete

discharging cycle is less for nanofluid circulated case. For example cell#4 temperature raises to 30.02°C for water circulated case whereas for it is 30.13 water circulated BTMS at 30°C and 2C-rate. The liquid circulated BTMS works more effectively as compared to liquid embedded BTMS as liquid sweeps heat from it. For higher 4C-rate, cell#4 temperature reaches up to 30.33°C and 30.06°C respectively for water cooled and nanofluid cooled systems. 23

Journal Pre-proof The effect of inlet liquid temperature (due to change in supply condition) is also analyzed for 35°C and plotted in fig 11. The transient behavior is similar, although there is higher cell temperature value during its discharging process.

Figure 10 Cell#4 transient response for LcBS at Ta = 30°C

24

Journal Pre-proof

Figure 11 Cell#4 transient response for LcBS at Ta = 35°C

5.2 Temperature uniformity in module Temperature uniformity can be studied with the help of temperature difference (∆T) within the module at any interval of time and computed as:

∆𝑇@𝐷𝑜𝐷 = 𝑇𝑚𝑎𝑥 (1,2,….7)@𝐷𝑜𝐷 ― 𝑇𝑚𝑖𝑛 (1,2,….7)@𝐷𝑜𝐷

where Tmax (1,2,….7)@DoD and Tmin (1,2,….7)@DoD is a maximum and minimum value of cell temperature among all cells at instantaneous DoD. LfBS: Figure 12 shows plots of temperature difference values for liquid embedded BTMS. As expected, the temperature difference is zero at the commencement of the battery operation. The significant temperature difference is observed for water-cooled BTMS, whereas it is less for nanofluid embedded BTMS. In the case of water-cooled BTMS at 2C-rate and Ta = 30°C, a temperature difference of 0.2°C is observed at ~12% of the discharge. It rises to 0.47°C and 0.93°C respectively for 50% and 100% of discharge interval whereas it is limited to a maximum value of 0.31°C for nanofluid embedded systems. At changed supply temperature

25

Journal Pre-proof and discharge rate condition (4C and Ta = 35°C), the temperature difference is around 0.086°C, 0.49°C and 0.87°C for water cooled systems respectively at 11.11 %, 50% and 100% of the depth of discharge. For the same case run under nanofluid, the temperature difference is limited to 0.36°C.

Figure 12 Maximum cell temperature differences for LfBS

LcBS: Fig 13 and Fig 14 show temperature difference computed at 30°C and 35°C respectively for both 2C and 4C-rates. Temperature uniformity in a module can improved with the circulation of cooling liquid as compared to liquid embedded systems. Even with a water flow rate of 0.01 kg/s with 30°C inlet, the temperature difference is limited to 0.04°C at the 2C rate and 0.097°C at 4C rate. In all cases, better uniformity observed for nanofluid circulated BTMS. There are several advantages of liquid circulated based BTMS. Firstly, temperature fluctuations in a module are present only during a small interval of the discharging period (observed up to 25% of the depth of discharge). Secondly, the maximum temperature difference is less as compared to a liquid filled system. For example, maximum ∆T was 26

Journal Pre-proof observed around ~1°C for liquid filled system whereas it is lesser than 0.17°C for liquid circulated systems.

Figure 13 Maximum cell temperature differences for LcBS at Ta = 30°C

Figure 14 Maximum cell temperature differences for LcBS at Ta = 35°C 27

Journal Pre-proof

5.3 Cell-wise temperature distribution Based on cell location in the module and its proximity to dissipate heat, cell temperature may differ from each other. The maximum cell temperature variations occur at the end of the discharge period. LfBS: Fig 15 shows cell temperature variation at 100% discharge condition for both C-rate and ambient conditions. Cells located at the interior of the module are at slightly hotter as compared to their counterpart cells. For example; at 2C-rate and 30°C, cell#1, cell#4 and cell#7 temperatures are respectively at 37.18°C, 37.80°C and 36.74°C whereas, at 4C-rate and 30°C, it rises to 41.14°C, 41.95°C and 40.66°C. The lesser cell temperatures deviations are observed for nanofluid cooled case around 36.77°C (cell#1), 36.90°C (cell#4) and 36.74°C (cell#7) at 2C-rate and 30°C. Similar cell-wise temperature distribution for other operating condition of 4C-rate and 35°C have shown in Figure 15.

LcBS: Fig 16 shows cell temperature variation for liquid circulated conditions. Cells nearer to the inlet (cell#1) are at relatively colder conditions. The cell#2 to cell#7 is dissipating the heat to the slightly warmer circulating liquid. It is because cooling liquid gets heated as it flows across cell#1 absorbs heat from it. Therefore cells cell#2 to cell#7 dissipate heat convectively to the warmer air. The cell present at the outlet ends (cell#7) are at a slightly higher temperature as compared to their counterpart preceding cells.

28

Journal Pre-proof

Figure 15 Cell-to-cell temperatures at 100%DoD for LfBS

Figure 16 Cell-to-cell temperatures at 100%DoD for LcBS

5.4 Cooling liquid temperature variation in module The temperature of the cooling liquid is monitored to understand heat collected during its use. Fig 17 show such a plot for both cases of the LiBS and LcBS arrangments. Liquid 29

Journal Pre-proof temperature values at the end of the discharge process (100% DoD) are used to plot its variation. LfBS: In all cases, the nanofluid temperature is found lower than water. For example, at the battery module operating at 2C-discharge rate and 30°C supply temperature, the water temperature rises to 37.5°C whereas nanofluid temperature limited to 36.80°C. At the 4C-discharge rate, water and nanofluid reach up to 41.08 and 40.29°C respectively for water and nanofluids. Battery module operating at a liquid inlet temperature of 35°C, the water temperature rises to 42.40°C and 46.40°C respectively for 2C and 4C rates. Under this condition, nanofluid temperature restricted to 41.93°C and 45.54°C respectively for 2C and 4C rates.

LcBS: It can be shown that liquid temperature is lower for liquid circulated systems as compared to liquid embedded systems. The Maximum liquid temperature rise is below 1°C for both discharge rates.

30

Journal Pre-proof

Figure 17 Cooling fluid temperatures at 100% DoD

6 Conclusions Pollution occurring from conventionally fueled transport vehicles can safely reduce with the electric cars employed with rechargeable Li-ion batteries. In the present study, two possible arrangements for battery cooling is suggested considering moderate to adverse battery operating conditions encountered in electric vehicles Based on the three-dimensional numerical investigation on the transient thermal behavior of Li-ion battery module the following conclusions are drawn:



Due to the modular nature of the suggested battery cooling system, the production and implementation of it in electric vehicles are easier.



At moderate discharge rate (2C) and relatively colder ambient temperature, the LfBS (liquid filled battery thermal management system) is adequate. The

31

Journal Pre-proof absence of components like heat exchanger and liquid circulating pump makes LfBS cost effective as compared to LcBS (Liquid circulated battery thermal management system). From a production point of view, LfBS simpler in operation. Such systems are expected to be targeted in electric vehicles running in colder climate countries. 

During hot outdoor temperature, a re-circulated air from the air-conditioning unit of electric vehicles can be utilized in such systems to maintain safe battery temperature. The provision of a suitable ducting system for the supply of re-circulated air from car cabin should be considered during the design phase of electric vehicles.



Electric vehicles that operate at higher discharge current can maintain within safe limits with the liquid circulated arrangement. The warmer liquid (after picking up heat from battery module) is suggested to exchange heat with either ambient air or re-circulated air from car cabin. Such type of cooling systems should be targeted for electric vehicles running in hot climate countries.



During extreme hot climate, the design should have a provision for the supply of fraction of conditioned cooled air for direct heat transfer from BTMS.



Temperature uniformity is higher for LcBS (Liquid circulated battery system) as compared to LfBS. Temperature uniformity within the module is essential for minimum long-term degradation. The study on cell-to-cell heat dissipation within the module is important for avoiding localized heat spots detrimental to the safe operating condition of a specific cell.



Battery temperature can reduce by using nanofluids in both cases of the battery module (LfBS and LcBS). The magnitude of heat dissipation from nanofluids in comparison with base fluid (example pure water) is not 32

Journal Pre-proof satisfactory to support its use. Therefore in electric vehicles, for implementing liquid cooled BTMS, a simple water flow system similar to the radiator is sufficient. The study showed the way for liquid cooled battery thermal management systems: LcBS and LfBS. Any production of electric vehicles with battery cooling system requires system level investigation. The future scope of the study should focus on separate analysis on various components like type and capacity of the heat exchanger, circulating pump, etc. The performance and location of this heat exchanger can be seen analogous to that of the radiator.

References Bandhauer, T.M., Garimella, S., Fuller, T.F., 2014. Temperature-dependent electrochemical heat generation in a commercial lithium-ion battery. J. Power Sources 247, 618–628. https://doi.org/https://doi.org/10.1016/j.jpowsour.2013.08.015 BCG, 2010. Batteries for Electric Cars [WWW Document]. URL http://www.bcg.com/documents/file36615.pdf Choi, S.U.S., Zhang, Z.G., Yu, W., Lockwood, F.E., Grulke, E.A., 2001. Anomalous thermal conductivity enhancement in nanotube suspensions. Appl. Phys. Lett. 79, 2252–2254. https://doi.org/10.1063/1.1408272 Corcione, M., 2011. Empirical correlating equations for predicting the effective thermal conductivity and dynamic viscosity of nanofluids. Energy Convers. Manag. 52, 789– 793. https://doi.org/https://doi.org/10.1016/j.enconman.2010.06.072 Deloitte, n.d. New market. New entrants. New challenges. Battery Electric Vehicles [WWW Document]. URL https://www2.deloitte.com/content/dam/Deloitte/uk/Documents/manufacturing/deloitteuk-battery-electric-vehicles.pdf Duangthongsuk, W., Wongwises, S., 2010. Comparison of the effects of measured and computed thermophysical properties of nanofluids on heat transfer performance. Exp. Therm. Fluid Sci. 34, 616–624. https://doi.org/https://doi.org/10.1016/j.expthermflusci.2009.11.012 Fan, L., Khodadadi, J.M., Pesaran, A.A., 2013. A parametric study on thermal management of an air-cooled lithium-ion battery module for plug-in hybrid electric vehicles. J. Power Sources 238, 301–312. https://doi.org/10.1016/j.jpowsour.2013.03.050 Fluent 6 Documentation , 2006. Fluent Inc., Lebanon, n.d. G-H Kim, and M.K.A.P., 2009. Integration Issues of Cells into Battery Packs for Plug-in and Hybrid Electric Vehicles, in: International Electrical Vehicle Symposium (EVS-24). p. 7. Giuliano, M.R., Prasad, A.K., Advani, S.G., 2012. Experimental study of an air-cooled thermal management system for high capacity lithium-titanate batteries. J. Power Sources 216, 345–352. https://doi.org/10.1016/j.jpowsour.2012.05.074 33

Journal Pre-proof Hallaj, S. Al, Selman, J.R., 2000. A Novel Thermal Management System for Electric Vehicle Batteries Using Phase-Change Material. J. Electrochem. Soc. 147, 3231. https://doi.org/10.1149/1.1393888 He, F., Li, X., Ma, L., 2014. Combined experimental and numerical study of thermal management of battery module consisting of multiple Li-ion cells. Int. J. Heat Mass Transf. 72, 622–629. https://doi.org/10.1016/j.ijheatmasstransfer.2014.01.038 Hu, C., Youn, B.D., Chung, J., 2012. A multiscale framework with extended Kalman filter for lithium-ion battery SOC and capacity estimation. Appl. Energy 92, 694–704. https://doi.org/https://doi.org/10.1016/j.apenergy.2011.08.002 Hung, Y., Chen, J., Teng, T., 2013. Feasibility Assessment of Thermal Management System for Green Power Sources Using Nanofluid. J. Nanomater. 2013, 1–11. Huo, Y., Rao, Z., Liu, X., Zhao, J., 2015. Investigation of power battery thermal management by using mini-channel cold plate. Energy Convers. Manag. 89, 387–395. https://doi.org/https://doi.org/10.1016/j.enconman.2014.10.015 Incropera, F.P., DeWitt, D.P., Bergman, T.L., Lavine, A.S., 2011. Fundamentals of Heat and Mass Transfer, 7th edition 1072. Jafarimoghaddam, A., Aberoumand, S., Aberoumand, H., Javaherdeh, K., 2017. Experimental Study on Cu/Oil Nanofluids through Concentric Annular Tube: A Correlation. Heat Transf. - Asian Res. 46, 251–260. https://doi.org/10.1002/htj.21210 Jarrett, A., Kim, I.Y., 2011. Design optimization of electric vehicle battery cooling plates for thermal performance. J. Power Sources 196, 10359–10368. https://doi.org/https://doi.org/10.1016/j.jpowsour.2011.06.090 Jilte, R.D., Kumar, R., 2018. Numerical investigation on cooling performance of Li-ion battery thermal management system at high galvanostatic discharge. Eng. Sci. Technol. an Int. J. 21, 957–969. https://doi.org/https://doi.org/10.1016/j.jestch.2018.07.015 Jilte, R.D., Kumar, R., Ma, L., 2019. Thermal performance of a novel confined flow Li-ion battery module. Appl. Therm. Eng. 146, 1–11. https://doi.org/10.1016/j.applthermaleng.2018.09.099 Jin, L.W., Lee, P.S., Kong, X.X., Fan, Y., Chou, S.K., 2014. Ultra-thin minichannel LCP for EV battery thermal management. Appl. Energy 113, 1786–1794. https://doi.org/https://doi.org/10.1016/j.apenergy.2013.07.013 Khan, M., Swierczynski, M., Kær, S., 2017. Towards an Ultimate Battery Thermal Management System: A Review. Batteries 3, 9. https://doi.org/10.3390/batteries3010009 Khanafer, K., Vafai, K., 2011. A critical synthesis of thermophysical characteristics of nanofluids. Int. J. Heat Mass Transf. 54, 4410–4428. https://doi.org/https://doi.org/10.1016/j.ijheatmasstransfer.2011.04.048 Kim, G.-H., Pesaran, A., Spotnitz, R., 2007. A three-dimensional thermal abuse model for lithium-ion cells. J. Power Sources 170, 476–489. https://doi.org/https://doi.org/10.1016/j.jpowsour.2007.04.018 Kim, Y., Mohan, S., Siegel, J., Stefanopoulou, A., 2013. Maximum Power Estimation of Lithium-Ion Batteries Accounting for Thermal and Electrical Constraints. ASME 2013 Dyn. Syst. Control Conf. DSCC 2013. Li, Y., Xie, H., Yu, W., Li, J., 2015. Liquid Cooling of Tractive Lithium Ion Batteries Pack with Nanofluids Coolant. J. Nanosci. Nanotechnol. 15, 3206–3211. https://doi.org/10.1166/jnn.2015.9672 Lin, Q., Yixiong, T., Ruizhen, Q., Zuomin, Z., Youliang, D., Jigiang, W., 1995. General safety considerations for high power Li/SOCl2 batteries. J. Power Sources 54, 127–133. https://doi.org/https://doi.org/10.1016/0378-7753(94)02052-5 Lisbona, D., Snee, T., 2011. A review of hazards associated with primary lithium and lithium-ion batteries. Process Saf. Environ. Prot. 89, 434–442. 34

Journal Pre-proof https://doi.org/https://doi.org/10.1016/j.psep.2011.06.022 Mahamud, R., Park, C., 2011. Reciprocating air flow for Li-ion battery thermal management to improve temperature uniformity. J. Power Sources 196, 5685–5696. https://doi.org/10.1016/j.jpowsour.2011.02.076 Marques, P., Garcia, R., Kulay, L., Freire, F., 2019. Comparative life cycle assessment of lithium-ion batteries for electric vehicles addressing capacity fade. J. Clean. Prod. 229, 787–794. https://doi.org/10.1016/j.jclepro.2019.05.026 Mondal, B., Lopez, C.F., Mukherjee, P.P., 2017. Exploring the efficacy of nanofluids for lithium-ion battery thermal management. Int. J. Heat Mass Transf. 112, 779–794. https://doi.org/10.1016/j.ijheatmasstransfer.2017.04.130 Nelson, P., Dees, D., Amine, K., Henriksen, G., 2002. Modeling thermal management of lithium-ion PNGV batteries. J. Power Sources 110, 349–356. https://doi.org/https://doi.org/10.1016/S0378-7753(02)00197-0 Pak, B.C., Cho, Y.I., 1998. Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles. Exp. Heat Transf. 11, 151–170. https://doi.org/10.1080/08916159808946559 Panchal, S., Dincer, I., Agelin-Chaab, M., Fraser, R., Fowler, M., 2016. Thermal modeling and validation of temperature distributions in a prismatic lithium-ion battery at different discharge rates and varying boundary conditions. Appl. Therm. Eng. 96, 190–199. https://doi.org/10.1016/j.applthermaleng.2015.11.019 Park, S., Jung, D., 2013. Battery cell arrangement and heat transfer fl uid effects on the parasitic power consumption and the cell temperature distribution in a hybrid electric vehicle. J. Power Sources 227, 191–198. https://doi.org/10.1016/j.jpowsour.2012.11.039 Pendergast, D.R., DeMauro, E.P., Fletcher, M., Stimson, E., Mollendorf, J.C., 2011. A rechargeable lithium-ion battery module for underwater use. J. Power Sources 196, 793– 800. https://doi.org/https://doi.org/10.1016/j.jpowsour.2010.06.071 Rani, M F H, Razlan, Z.M., Bakar, S.A., Desa, H., Wan, W.K., Ibrahim, I., Kamarrudin, N.S., Bin-, N.A., 2017. Analysis of Hybrid Interface Cooling System Using Air Ventilation and Nanofluid, in: AIP Conference Proceedings. pp. 1–8. https://doi.org/10.1063/1.5002266 Rani, M. F.H., Razlan, Z.M., Bakar, S.A., Desa, H., Wan, W.K., Ibrahim, I., Kamarrudin, N.S., Bin-Abdun, N.A., 2017. Experimental study of hybrid interface cooling system using air ventilation and nanofluid, in: AIP Conference Proceedings. pp. 1–9. https://doi.org/10.1063/1.5002267 Rao, Z., Wang, S., 2011. A review of power battery thermal energy management. Renew. Sustain. Energy Rev. 15, 4554–4571. https://doi.org/10.1016/j.rser.2011.07.096 Sabbah, R., Kizilel, R., Selman, J.R., Al-Hallaj, S., 2008. Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution. J. Power Sources 182, 630–638. https://doi.org/10.1016/j.jpowsour.2008.03.082 Saw, L.H., Ye, Y., Tay, A.A.O., 2016a. Integration issues of lithium-ion battery into electric vehicles battery pack. J. Clean. Prod. 113, 1032–1045. https://doi.org/10.1016/j.jclepro.2015.11.011 Saw, L.H., Ye, Y., Tay, A.A.O., Chong, W.T., Kuan, S.H., Yew, M.C., 2016b. Computational fluid dynamic and thermal analysis of Lithium-ion battery pack with air cooling. Appl. Energy 177, 783–792. https://doi.org/10.1016/j.apenergy.2016.05.122 Sefidan, A.M., Sojoudi, A., Saha, S.C., 2017. Nanofluid-based cooling of cylindrical lithiumion battery packs employing forced air flow. Int. J. Therm. Sci. 117, 44–58. https://doi.org/10.1016/j.ijthermalsci.2017.03.006 Selman, J.R., Hallaj, S. Al, Uchida, I., Hirano, Y., 2001. Cooperative research on safety 35

Journal Pre-proof fundamentals of lithium batteries. J. Power Sources 97–98, 726–732. https://doi.org/https://doi.org/10.1016/S0378-7753(01)00732-7 Sun, H., Wang, X., Tossan, B., Dixon, R., 2012. Three-dimensional thermal modeling of a lithium-ion battery pack. J. Power Sources 206, 349–356. https://doi.org/10.1016/j.jpowsour.2012.01.081 T. H. Kuehn and R. J.Goldstein, 1976. An experimental and theoretical study of natural convection in the annulus between horizontal concentric cylinders. J. Fluid Mech. 74, 695–719. Tran, L., Lopez, Jorge, Lopez, Jesus, Uriostegui, A., Barrera, A., Nanotechnology, M.Á.N.Á., 2017. Li-ion battery cooling system integrates in nano-fluid environment. Appl. Nanosci. 7, 25–29. https://doi.org/10.1007/s13204-016-0539-6 van Schalkwijk, W., Scrosati, B., 2002. Advances in Lithium Ion Batteries Introduction, in: Advances in Lithium-Ion Batteries. https://doi.org/10.1007/0-306-47508-1_1 Waag, W., Sauer, D.U., 2013. Adaptive estimation of the electromotive force of the lithiumion battery after current interruption for an accurate state-of-charge and capacity determination. Appl. Energy 111, 416–427. https://doi.org/https://doi.org/10.1016/j.apenergy.2013.05.001 Wang, C.H., Lin, T., Huang, J.T., Rao, Z.H., 2015. Temperature response of a high power lithium-ion battery subjected to high current discharge. Mater. Res. Innov. 19, S2156– S2160. https://doi.org/10.1179/1432891715Z.0000000001318 Wang, T., Tseng, K.J., Zhao, J., Wei, Z., 2014. Thermal investigation of lithium-ion battery module with different cell arrangement structures and forced air-cooling strategies. Appl. Energy 134, 229–238. https://doi.org/10.1016/j.apenergy.2014.08.013 Williford, R.E., Viswanathan, V. V, Zhang, J.-G., 2009. Effects of entropy changes in anodes and cathodes on the thermal behavior of lithium ion batteries. J. Power Sources 189, 101–107. https://doi.org/https://doi.org/10.1016/j.jpowsour.2008.10.078 Wu, M.-S., Liu, K.H., Wang, Y.-Y., Wan, C.-C., 2002. Heat dissipation design for lithiumion batteries. J. Power Sources 109, 160–166. https://doi.org/https://doi.org/10.1016/S0378-7753(02)00048-4 Xuan, Y., Roetzel, W., 2000. Conceptions for heat transfer correlation of nanofluids. Int. J. Heat Mass Transf. 43, 3701–3707. https://doi.org/https://doi.org/10.1016/S00179310(99)00369-5 Yang, N., Zhang, X., Li, G., Hua, D., 2015. Assessment of the forced air-cooling performance for cylindrical lithium-ion battery packs: A comparative analysis between aligned and staggered cell arrangements. Appl. Therm. Eng. 80, 55–65. https://doi.org/10.1016/j.applthermaleng.2015.01.049 Zhang, X., Liu, C., Rao, Z., 2018. Experimental investigation on thermal management performance of electric vehicle power battery using composite phase change material, Journal of Cleaner Production. Elsevier Ltd. https://doi.org/10.1016/j.jclepro.2018.08.076 Zhao, J., Rao, Z., Li, Y., 2015. Thermal performance of mini-channel liquid cooled cylinder based battery thermal management for cylindrical lithium-ion power battery. Energy Convers. Manag. 103, 157–165. https://doi.org/10.1016/j.enconman.2015.06.056

36

Journal Pre-proof

Highlights    

Cooling of the battery module with liquid filled and liquid circulated BTMS Performance comparison based on water and nanofluid as cooling media Ambient conditions and electric vehicle’s air-conditioned supply air used Applicability for each case is illustrated with analysis.