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A magneto-mechano-electric (MME) energy harvester based on rectangular cymbal structure
Sensors and Actuators A 316 (2020) 112400
Contents lists available at ScienceDirect
Sensors and Actuators A: Physical journal homepage: www.elsevier.com/locate/sna
A magneto-mechano-electric (MME) energy harvester based on rectangular cymbal structure Zhonghui Yu a , Zhaoqiang Chu a , Jikun Yang a , Mohammad Javad Pourhosseini Asl a , Xiaoting Yuan a , Yang Yu a , Ge Nie c , Huilong Qi c , Shuxiang Dong a,b,∗ a
Department of Materials Science and Engineering, College of Engineering, Peking University, 100871, Beijing, China Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKL-MEMD), Peking University, 100871, Beijing, China c State Key Laboratory of Coal-Based Low-Carbon Energy, ENN Science & Technology Development Co, Ltd, Langfang, 065001, China b
a r t i c l e
i n f o
Article history: Received 31 May 2020 Received in revised form 5 October 2020 Accepted 23 October 2020 Keywords: Magnetoelectric Piezoelectric Energy harvesting Metglass
a b s t r a c t In this work, we report a magneto-mechano-electric (MME) energy harvester with a rectangular cymbal structure consisting of a piezoelectric ceramic plate and magnetostrictive alloy (Metglass) foils. The magnetic field induced voltage was then predicted by using finite element analysis. Experimental results show that under a magnetic field excitation of 8 Oe at 180 Hz (resonance frequency), the MME energy harvester can generate a peak-peak output power of 5.7 mW and peak-peak current of 2.3 mA, respectively, for a load resistance of 5.6 k, which allow to drive 10 LEDs lighting directly and stably. Correspondingly, its power density is 5.1 mW cm−3 at Hac =7 Oe, which is comparable with previous reports about traditional cantilever structure MME energy harvester using a piezoelectric single crystal. This work confirms that the MME energy harvester is a promising candidate for powering wireless sensors and other micro-energy smart electronics using the stray magnetic field, or even mechanical vibration energy in environment. © 2020 Published by Elsevier B.V.
1. Introduction The fast development of Internet of Things (IoT) and wireless sensor networks (WSNs) is promoting the development of energy harvesting systems [1]. Harvesting energy from ambient environment such as kinetic energy, heat, solar energy, and stray magnetic field energy etc., has been expected to be a promising approach [2–5]. The low-frequency (< 300 Hz) stray noise magnetic field generated from the manufacturing rotating machines, electronic devices and subways etc. exist widely, being freely to be harvested [6]. Harvesting the low-amplitude and low-frequency magnetic field based on Faraday’s law induction is normally suffering from its low efficiency [5,7,8]. Recently, magnetoelectric (ME) composites, which can convert magnetic field energy into electric field energy mediated by strain, exhibit the potential application prospect in magnetic field sensing [9,10] and energy harvesting [1,11–13]. Compared to electromagnetic generators, one ME composite features with higher efficiency to convert low-amplitude magnetic field into electric
∗ Corresponding author at: Department of Materials Science and Engineering, College of Engineering, Peking University, 100871, Beijing, China. E-mail address: [email protected] (S. Dong). https://doi.org/10.1016/j.sna.2020.112400 0924-4247/© 2020 Published by Elsevier B.V.
energy, especially in low-frequency range [14]. Correspondingly, magneto-mechano-electric (MME) energy harvesters have been proposed and investigated based on ME composite [14,15]. Dong et al. first proposed a ME composite multimodal system for harvesting magnetic and mechanical energy in 2008 [11]. Liu et al. reported MME composite consisting of NdFeB and copper cantilever for harvesting ambient low-frequency magnetic field energy [15]. By employing low loss piezoelectric single crystal or micro fiber composite (MFC), the enhanced output power performance of MME energy harvesters was further reported by Ryu et al. [5,14]. In addition, Annapureddy et al. used textured Fe-Ga alloy as magnetostrictive phase in MME harvesters to improve the output power, and they successfully drove a smart watch with IoT sensors [1]. A bimorph structure was commonly used in above mentioned works, where a cantilever and a proof mass can lower the resonance frequency below 100 Hz. However, proof mass loaded at cantilever structure would cause line cracks in several minutes in response to high-amplitude resonant vibration of 50–100 Hz [16]. In 2004, Kim et al. reported a cymbal structure composed of metal–ceramic composite exhibiting the enhanced endurance and mechanical stability compared with a bimorph structure [16]. Gao et al. reported vibration energy harvester based on rectangular cymbal structure consisting of copper cap and PNN-PZT ceramic composite, which showed high output peak-peak current of 2.5 mApp at the acceler-
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Sensors and Actuators A 316 (2020) 112400
ation of 3.5 g [17]. These reports indicate that cymbal structure is promised for mechanical vibration energy harvesting. However, employing cymbal structure to harvest magnetic field energy is rarely reported. Here, we present rectangle cymbal structure MME energy harvester. In our harvester, one highpiezoelectric PZT-5 ceramic plate is sandwiched between two metal caps made of Metglass foils. We will see that the compact structure could efficiently and stably convert magnetic field energy into electric field energy. Experimental results showed that the rectangle cymbal structure MME energy harvester can generate a peak-peak output power of 5.7 mW and peak-peak current of 2.3 mApp , respectively, under an excitation magnetic field of HAC =8 Oe at resonance frequency. And its output voltage waveform still remains very stable under HAC of 8 Oe after 47,500 working cycles, indicating its potential for harvesting the stray magnetic field even mechanical vibration energy in environment.
3. Results and discussion 3.1. Geometric structure of MME energy harvester Fig. 1(a) shows the geometric structure of MME energy harvester. As shown in Fig. 1(a), the bottom cap of cymbal is fixed on the base by epoxy. One magnet NdFeB is loaded at the top of cymbal, which, on the one hand, provides a DC bias magnetic field and also a pre-stress to the Metglass caps along 3 and 1 directions, on the other hand, it also acts as a proof mass. 3.2. Work mechanism of MME energy harvester As shown in Fig. 1(b), the MME energy harvester can be considered to be operated in L–T (longitudinally magnetization and transversely polarization) mode and its working mechanism can be explained as follows: one Metglass was fixed at base, and another cap was stressed by NdFeB magnets; when applying AC magnetic field HAC along longitudinal (or 1) direction, the Metglass layer will be induced an extension strain along 1 direction due to magnetostriction effect; because of flexural motion in cymbal structure [18], the loaded proof mass M is also forced to move along 3 direction with an acceleration a; According to equation of F = M*a, the proof mass would generate 3-direciton inertial force under 1-direction magnetic field; the induced inertial force finally is transferred to piezoelectric plate along 1 direction via the cymbal structure with a force amplification factor N. Therefore, a large induced ME voltage is expected via d31 effect. Note that external mechanical force F or vibrations in environment can also induce an inertial/impact force acting on the loaded proof mass and induce output voltage via direct piezoelectric effect. It should be pointed that the extensional deformation of one ceramics plate is more uniform compared to bending deformation in a bimorph structure [16,19], which will allow it to produce a more stable output voltage. As illustrated in Fig. 1(b), a magnetic moment effect originated from interaction between HAC and magnet NdFeB could also induce vibration of top cap along 3 direction, which would be positive to improve the output power of MME energy harvester [15].
2. Experimental The magneto-mechano-electric (MME) energy harvester was fabricated by using one thickness-poled PZT-5 ceramic plate (Kunshan PanTe Co., Ltd., China,) and two rectangular metal caps each consisting of 12-layer magnetostrictive Metglass (FeBSiC, 2605SA1) foils. The piezoelectric ceramic plate operating in d31 mode was sandwiched between two Metglass caps in thickness direction with epoxy resin (to bond them together). And the cavity distance from piezoelectric ceramics plate to metglass cap is 6 mm. The sizes of ceramic plate are 60 mm in length, 20 mm in width and 0.2 mm in thickness. The dimension of each Metglass foil is 120 mm in length, 20 mm in width and 0.025 mm in thickness. Some epoxy resin was coated on two sides of Metglass caps to prevent electric leakage. Then, an AC magnetic field was coaxially generated by using a home-made solenoid coil powered by a Function/Arbitrary Waveform Generator (33522, Agilent, USA) and a power amplifier. And the AC magnetic field strength was calculated according to the output current I from power amplifier. The DC magnetic field was provided by magnets of NdFeB loaded on the top of one Metglass cap. The ME coupling coefficient of the magnetic energy harvester was calculated through VRMS /(tPZT -5 · HAC ), where VRMS , tPZT -5 , and HAC are output voltage (in RMS), thickness of the piezoelectric layer, and external AC magnetic field intensity (in RMS), respectively. The induced open-circuit voltages from piezoelectric phase (PZT-5 ceramics) were measured with an oscilloscope (Keysight MSOX4024A) under varying AC magnetic field.
3.3. Simulated results of MME energy harvester Fig. 2(a) further shows the extensional deformation modeling of the cymbal structure MME energy harvester under AC magnetic field HAC excitation (by using finite element analysis (FEA), Comsol software). Fig. 2(b) shows the FEA simulated HAC induced acceleration a at resonance frequency according to the
Fig. 1. (a) schematic diagram and structure of MME energy harvester, (b) diagram of work mechanism in the proposed MME energy harvester. 2
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Sensors and Actuators A 316 (2020) 112400
Fig. 2. FEA modeling results of the rectangular cymbal structure under AC magnetic field excitation, (a) HAC -induced acceleration and deformation at first vibration model, and (b) acceleration a as a function of HAC for a loaded proof mass M (= 20 gf) at resonance.
pizomagnetic-piezoelectric analogy and a given piezomagnetic coefficient d33,m =2 ppm/Oe [12]. It is clear seen that the maximum vibration acceleration value of the loaded proof mass M (= 20 gf) is about 32 m/s2 (∼3.2 g) under 1 Oe AC magnetic field excitation. The HAC -induced acceleration a produces an inertial force (F(t) = Ma) acting on the magnetic mass and then an axial dynamic tension or pressing force F1 (t) against the piezoelectric plate via two laminated cymbal structured Metglas layers. According to the geometric parameter of the cymbal structure, F1 (t) can be found as F1 (t) =F(t)N=MaN
Fig. 3. (a) open-circuit peak-peak output voltage under varying HAC and (b) ME voltage coefficient of MME energy harvester as a function of excitation frequency.
3.4. Measured results of MME energy harvester Fig. 3(a) shows the measured open-circuit peak-peak output voltage (Vpp ) from PZT-5 ceramic in MME energy harvester as a function of excitation frequency under HAC with varying amplitude of 1, 3 and 5 Oe. It can be seen that higher excitation magnetic field HAC induces a higher ME voltage, and ME voltage reaches its maximum value of 6.2 V under HAC =5 Oe at resonance frequency of ∼180 Hz. Fig. 3(b) further shows ME voltage coefficient ˛ME of the MME harvester as a function of excitation frequency under HAC =1 Oe, and the maximum value of ˛ME is around 48 V/cm Oe at resonance frequency of 180 Hz. Compared with the calculated value of 148.8 V/cm Oe, which is about 3 times difference with the observed ME coupling coefficient in MME device due to (i) non optimum DC magnetic bias, and (ii) mechanical load effect of magnetic mass. These values are comparable to that of a bimorph structured magnetoelectric energy harvesters [20]. Fig. 4(a–i) shows the output ME voltage waveform of MME energy harvester under varying HAC excitation amplitude of 1, 3, 5 and 7 Oe at resonance frequency of 180 Hz. The peak-peak output voltage of MME energy harvester increases with excitation magnetic field amplitude. Fig. 4(a-ii) further shows the enlarged output ME voltage waveform of the harvester under HAC =1 Oe, and a quite stable voltage waveform is found. Fig. 4(b) characterizes the durability of the MME energy harvester for long-cycle opera-
(1)
where N = 1/tan is a force amplification factor of the cymbal structure. Clearly, designing a suitable angle in cymbal structure (see Fig.1 (a)) will result in an amplified force applied to the piezoelectric plate. It should be noted that although the magnetic mass M also applies a force to the piezoelectric plate, but it can be regarded as only a bias force. In this case, the induced voltage Vout from piezoelectric ceramic plate can be expressed as: Vout = g31 tF1 /Sp
(2)
where, g31 is piezoelectric voltage coefficient, t and Sp are the thickness and cross-sectional area of the piezoelectric ceramic plate, respectively. According to Eq. 2, the HAC -induced voltage Vout is about 3 V at resonance frequency of first vibration model, and correspondingly, its ME coupling coefficient ˛ME (= Vout /tPZT -5 · HAC ) at resonance is 148.8 V/cm Oe. We will see that the simulated results are about three times higher than measured values due to the ideal model. 3
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Fig. 4. (a-i) the time line of output voltage waveform generated by MME energy harvester under varying HAC excitation, (b-i) durability test over 47,500 working cycles under HAC of 8 Oe; (a-ii) and (b-ii) enlarging voltage waveforms.
Fig. 5. The generated power (a) and current (b) of MME energy harvester as a function of load resistance under varying HAC excitation, (c) photograph of measurement setup, (d) photograph of 10 LEDs driven by the MME energy harvester.
tion. It is clear seen that under HAC of 8 Oe after 47,500 working cycles, the output voltage waveform of the MME harvester still keep stable: the time line of peak voltage maintains flat, implying there is no any observed performance declined. The cymbal structure is more symmetric and compact, and the excited longitudinal mode deformation in piezoelectric ceramic plate is also more uni-
form in comparison to the bimorph structure operating in bending mode [16,19]; therefore, cymbal structure could avoid the bending fatigue effect of PZT ceramic plate. According to the relationship of Pp = Vpp 2 /RL , the peak-peak output power Pp of the MME harvester for a load resistance RL can be estimated. And peak-peak current was calculated based on 4
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Sensors and Actuators A 316 (2020) 112400
Ohm’s law. Fig. 5 (a) and (b) show peak-peak output power Pp and peak-peak output current Ipp as a function of RL under varying AC magnetic field HAC excitation at resonance frequency of 180 Hz. It is clearly seen that both Pp and Ipp increase as HAC , and the maximum peak-peak output power Pp and Ipp under HAC =8 Oe are about 5.7 mW and 2.3 mApp , respectively, for an optimized load resistance of 5.6 k. Here, we define power density of MME energy harvester as the ratio of output power value to piezoelectric phase volume. The corresponding power density of 5.1 mW cm−3 at 7 Oe is comparable with those of cantilever type MME harvester using a low-loss PMN-PZT piezoelectric single crystal corresponding to 9.3 mW cm−3 [14]. The high peak-peak output power can be ascribed to following reasons: (i) the amplified piezoelectric coefficient deff of the cymbal structure, (ii) inertial force effect of the loaded magnet as proof mass, and (iii) the relative lower internal resistance of the non-laminated ceramic plate in the MME energy harvester. Finally, the MME energy harvester was used to drive lightemitting diodes (LEDs) with a full wave rectifying bridge, see Fig. 5(c) for measurement setup. It can be seen in Fig. 5(d) that under AC magnetic field excitation, the MME energy harvester could light up 10 LEDs stably in real time, indicating well working performance and its potential to be used as micro-energy source of wire-less sensor networks in magnetic field noise or mechanical vibration noise circumstance.
References [1] V. Annapureddy, S.-M. Na, G.-T. Hwang, M.G. Kang, R. Sriramdas, H. Palneedi, et al., Exceeding milli-watt powering magneto-mechano-electric generator for standalone-powered electronics, Energy Environ. Sci. 11 (2018) 818–829. [2] H. Vocca, I. Neri, F. Travasso, L. Gammaitoni, Kinetic energy harvesting with bistable oscillators, Appl. Energy 97 (2012) 771–776. [3] Y. Tian, C.Y. Zhao, A review of solar collectors and thermal energy storage in solar thermal applications, Appl. Energy 104 (2013) 538–553. [4] Q. Dong, Y. Fang, Y. Shao, P. Mulligan, J. Qiu, L. Cao, et al., Electron-hole diffusion lengths & 175 m in solution-grown CH3 NH3 PbI3 single crystals, Science 347 (2015) 967. [5] M.G. Kang, R. Sriramdas, H. Lee, J. Chun, D. Maurya, G.T. Hwang, et al., High power magnetic field energy harvesting through amplified magneto-mechanical vibration, Adv. Energy Mater. 8 (2018) 1703313. [6] C. Xu, B. Ren, W. Di, Z. Liang, J. Jiao, L. Li, et al., Cantilever driving low frequency piezoelectric energy harvester using single crystal material 0.71Pb(Mg1/3 Nb2/3 )O3 -0.29PbTiO3 , Appl. Phys. Lett. 101 (2012) 033502. ´ Wireless [7] A. Kurs, A. Karalis, R. Moffatt, J.D. Joannopoulos, P. Fisher, M. Soljaˇcic, power transfer via strongly coupled magnetic resonances, Science 317 (2007) 83. [8] X. Wei, Z. Wang, H.Je. Dai, A Critical Review of Wireless Power Transfer via Strongly Coupled Magnetic Resonances, 7, 2014, pp. 4316–4341. [9] Z. Chu, M. PourhosseiniAsl, S. Dong, Review of multi-layered magnetoelectric composite materials and devices applications, J. Phys. D 51 (2018) 243001. [10] Z. Chu, Z. Yu, M. PourhosseiniAsl, C. Tu, S. Dong, Enhanced low-frequency magnetic field sensitivity in magnetoelectric composite with amplitude modulation method, Appl. Phys. Lett. 114 (2019) 132901. [11] S. Dong, J. Zhai, J.F. Li, D. Viehland, S. Priya, Multimodal system for harvesting magnetic and mechanical energy, Appl. Phys. Lett. 93 (2008) 103511. [12] Z. Chu, H. Shi, W. Shi, G. Liu, J. Wu, J. Yang, et al., Enhanced Resonance Magnetoelectric Coupling in (1-1) Connectivity Composites, Adv. Mater. 29 (2017) 1606022. [13] Z. Chu, V. Annapureddy, M. PourhosseiniAsl, H. Palneedi, J. Ryu, S. Dong, Dual-stimulus magnetoelectric energy harvesting, MRS Bull. 43 (2018) 199–205. [14] V. Annapureddy, M. Kim, H. Palneedi, H.-Y. Lee, S.-Y. Choi, W.-H. Yoon, et al., Low-Loss Piezoelectric Single-Crystal Fibers for Enhanced Magnetic Energy Harvesting with Magnetoelectric Composite, Adv. Energy Mater. 6 (2016) 1601244. [15] G. Liu, P. Ci, S. Dong, Energy harvesting from ambient low-frequency magnetic field using magneto-mechano-electric composite cantilever, Appl. Phys. Lett. 104 (2014) 032908. [16] H.W. Kim, A. Batra, S. Priya, K. Uchino, D. Markley, R.E. Newnham, et al., Energy harvesting using a piezoelectric “Cymbal” transducer in dynamic environment, J. Appl. Phys. 43 (2004) 6178–6183. [17] J.F. Fernandez, A. Dogan, Q.M. Zhang, J.F. Tressler, R.E. Newnham, Hollow piezoelectric composites, Sens. Actuators A Phys. 51 (1995) 183–192. [18] X. Gao, J. Wu, Y. Yu, Z. Chu, H. Shi, S. Dong, Giant piezoelectric coefficients in relaxor piezoelectric ceramic PNN-PZT for vibration energy harvesting, Adv. Funct. Mater. 28 (2018) 1706895. [19] J. Yang, Z. Li, X. Xin, X. Gao, X. Yuan, Z. Wang, et al., Designing electromechanical metamaterial with full nonzero piezoelectric coefficients, Sci. Adv. 5 (2019), eaax1782. [20] Y. Zhou, D.J. Apo, S. Priya, Dual-phase self-biased magnetoelectric energy harvester, Appl. Phys. Lett. 103 (2013) 192909.
4. Conclusion In summary, we designed and fabricated a magneto-mechanoelectric (MME) energy harvester with a laminated rectangular cymbal structure consisting of two multilayer Metglass caps and a piezoelectric ceramic plate. The magnetic field induced voltage in the MME energy harvester was predicted by using FEA. Experimental results show that under AC magnetic field excitation of 8 Oe, the MME energy harvester can generate the maximum peak-peak output power of 5.7 mW and peak-peak current of 2.3 mApp for a matching load resistance of 5.6 k. The generated power density of 5.1 mW cm−3 at at Hac =7 Oe, is even comparable with previous reports about MME energy harvester using a low-loss PMN-PZT piezoelectric single crystal. It still exhibits stable working performance after 47,500 working cycles. Higher output power is expected to be obtained by further optimizing the structure and material parameters of both Metglass and piezoelectric ceramic. The proposed MME energy harvester has potential to be used for wireless sensors and other related micro-energy smart electronics.
Biographies Data statement Zhonghui Yu is a graduate student in the Department of Materials Science and Engineering in the College of Engineering at Peking University, China. He received his B.Sc. in Materials Science and Engineering from Hubei University of Wuhan, China, in 2018. His current research focuses on piezoelectric materials, magnetic field sensors, and energy harvesters.
The data that support the findings of this study are available from the corresponding author upon reasonable request. Declaration of Competing Interest
Zhaoqiang Chu is a Ph.D candidate at Department of Materials Science & Engineering of the College of Engineering in Peking University. He received his M.S. degree in material science from University of Science and Technology Beijing (USTB), Beijing, China, 2015. He has been working on Magneoelectric and Piezoelectric Materials, Magnetic Sensors and Energy Harvesters in Prof. Dong’s group since 2015.
The authors declare that they have no conflict of interest. Acknowledgments
Jikun Yang is currently pursuing the Ph.D. degree in advanced materials and mechanics from Peking University, Beijing, China. He received the B.E. degree in physics from University of Science and Technology Beijing, China, in 2016.His research interests include piezoelectric materials and devices, metamaterials and 3D printing ceramics.
This work was supported by the National Natural Science Foundation of China (Grant Nos 51772005, 51132001) and Xin’ao Company.
Mr. MohammadJavad PourhosseiniAsl was born in Khorramabad, Iran, in 1987. He was awarded the B.Sc. and M.Sc. in Materials Science and Engineering in 2011 and 2014, respectively. He is a Ph.D. candidate majoring in advanced materials and mechanics at Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, China. His current research interests include piezoelectric and magnetic materials, magnetoelectric (ME) composite, energy harvesting, energy conversion, multi-functional materials and development of ME sensors and gyrators.
Appendix A. Supplementary data Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.sna.2020. 112400. 5
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Xiaoting Yuan is currently pursuing the Ph.D. degree in advanced materials and mechanics from Peking University, Beijing, China. Her research interests include piezoelectric materials and devices, metamaterials and 3D printing ceramics.
Tsinghua University, China. Dr. Dong was a research associate at Materials Research Institute, Pennsylvania State University, State College, PA, from Jan., 2000–Dec., 2001, and a research scientist and research professor at Materials Science & Engineering, Virginia Tech, Blacksburg, VA, from Jan., 2002–May 2008. Professor Dong’s research focuses on piezoelectric ceramics and magnetoelectric composite materials, piezoelectric actuators and micromotors, magnetic sensors, smart electronic devices, and their applications. He has authored over 160 peer-reviewed papers and 30 patents. Prof. Dong was chosen as Most Cited Chinese Researchers in 2014–2019, who were regarded as most influential scientists in the world by Elsevier.
Yang Yu received Ph.D. degree in physics from Wuhan University, Wuhan, China. in 2020. His research interests include piezoelectric materials and devices. Ge Nie is an engineer in Xinao Company. Huilong Qi is an engineer in Xinao Company. Shuxiang Dong is Professor of Materials Science & Engineering at College of Engineering, Peking University, China. Professor Dong holds MSc and PhD degrees from
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Contents lists available at ScienceDirect
Sensors and Actuators A: Physical journal homepage: www.elsevier.com/locate/sna
A magneto-mechano-electric (MME) energy harvester based on rectangular cymbal structure Zhonghui Yu a , Zhaoqiang Chu a , Jikun Yang a , Mohammad Javad Pourhosseini Asl a , Xiaoting Yuan a , Yang Yu a , Ge Nie c , Huilong Qi c , Shuxiang Dong a,b,∗ a
Department of Materials Science and Engineering, College of Engineering, Peking University, 100871, Beijing, China Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKL-MEMD), Peking University, 100871, Beijing, China c State Key Laboratory of Coal-Based Low-Carbon Energy, ENN Science & Technology Development Co, Ltd, Langfang, 065001, China b
a r t i c l e
i n f o
Article history: Received 31 May 2020 Received in revised form 5 October 2020 Accepted 23 October 2020 Keywords: Magnetoelectric Piezoelectric Energy harvesting Metglass
a b s t r a c t In this work, we report a magneto-mechano-electric (MME) energy harvester with a rectangular cymbal structure consisting of a piezoelectric ceramic plate and magnetostrictive alloy (Metglass) foils. The magnetic field induced voltage was then predicted by using finite element analysis. Experimental results show that under a magnetic field excitation of 8 Oe at 180 Hz (resonance frequency), the MME energy harvester can generate a peak-peak output power of 5.7 mW and peak-peak current of 2.3 mA, respectively, for a load resistance of 5.6 k, which allow to drive 10 LEDs lighting directly and stably. Correspondingly, its power density is 5.1 mW cm−3 at Hac =7 Oe, which is comparable with previous reports about traditional cantilever structure MME energy harvester using a piezoelectric single crystal. This work confirms that the MME energy harvester is a promising candidate for powering wireless sensors and other micro-energy smart electronics using the stray magnetic field, or even mechanical vibration energy in environment. © 2020 Published by Elsevier B.V.
1. Introduction The fast development of Internet of Things (IoT) and wireless sensor networks (WSNs) is promoting the development of energy harvesting systems [1]. Harvesting energy from ambient environment such as kinetic energy, heat, solar energy, and stray magnetic field energy etc., has been expected to be a promising approach [2–5]. The low-frequency (< 300 Hz) stray noise magnetic field generated from the manufacturing rotating machines, electronic devices and subways etc. exist widely, being freely to be harvested [6]. Harvesting the low-amplitude and low-frequency magnetic field based on Faraday’s law induction is normally suffering from its low efficiency [5,7,8]. Recently, magnetoelectric (ME) composites, which can convert magnetic field energy into electric field energy mediated by strain, exhibit the potential application prospect in magnetic field sensing [9,10] and energy harvesting [1,11–13]. Compared to electromagnetic generators, one ME composite features with higher efficiency to convert low-amplitude magnetic field into electric
∗ Corresponding author at: Department of Materials Science and Engineering, College of Engineering, Peking University, 100871, Beijing, China. E-mail address: [email protected] (S. Dong). https://doi.org/10.1016/j.sna.2020.112400 0924-4247/© 2020 Published by Elsevier B.V.
energy, especially in low-frequency range [14]. Correspondingly, magneto-mechano-electric (MME) energy harvesters have been proposed and investigated based on ME composite [14,15]. Dong et al. first proposed a ME composite multimodal system for harvesting magnetic and mechanical energy in 2008 [11]. Liu et al. reported MME composite consisting of NdFeB and copper cantilever for harvesting ambient low-frequency magnetic field energy [15]. By employing low loss piezoelectric single crystal or micro fiber composite (MFC), the enhanced output power performance of MME energy harvesters was further reported by Ryu et al. [5,14]. In addition, Annapureddy et al. used textured Fe-Ga alloy as magnetostrictive phase in MME harvesters to improve the output power, and they successfully drove a smart watch with IoT sensors [1]. A bimorph structure was commonly used in above mentioned works, where a cantilever and a proof mass can lower the resonance frequency below 100 Hz. However, proof mass loaded at cantilever structure would cause line cracks in several minutes in response to high-amplitude resonant vibration of 50–100 Hz [16]. In 2004, Kim et al. reported a cymbal structure composed of metal–ceramic composite exhibiting the enhanced endurance and mechanical stability compared with a bimorph structure [16]. Gao et al. reported vibration energy harvester based on rectangular cymbal structure consisting of copper cap and PNN-PZT ceramic composite, which showed high output peak-peak current of 2.5 mApp at the acceler-
Z. Yu, Z. Chu, J. Yang et al.
Sensors and Actuators A 316 (2020) 112400
ation of 3.5 g [17]. These reports indicate that cymbal structure is promised for mechanical vibration energy harvesting. However, employing cymbal structure to harvest magnetic field energy is rarely reported. Here, we present rectangle cymbal structure MME energy harvester. In our harvester, one highpiezoelectric PZT-5 ceramic plate is sandwiched between two metal caps made of Metglass foils. We will see that the compact structure could efficiently and stably convert magnetic field energy into electric field energy. Experimental results showed that the rectangle cymbal structure MME energy harvester can generate a peak-peak output power of 5.7 mW and peak-peak current of 2.3 mApp , respectively, under an excitation magnetic field of HAC =8 Oe at resonance frequency. And its output voltage waveform still remains very stable under HAC of 8 Oe after 47,500 working cycles, indicating its potential for harvesting the stray magnetic field even mechanical vibration energy in environment.
3. Results and discussion 3.1. Geometric structure of MME energy harvester Fig. 1(a) shows the geometric structure of MME energy harvester. As shown in Fig. 1(a), the bottom cap of cymbal is fixed on the base by epoxy. One magnet NdFeB is loaded at the top of cymbal, which, on the one hand, provides a DC bias magnetic field and also a pre-stress to the Metglass caps along 3 and 1 directions, on the other hand, it also acts as a proof mass. 3.2. Work mechanism of MME energy harvester As shown in Fig. 1(b), the MME energy harvester can be considered to be operated in L–T (longitudinally magnetization and transversely polarization) mode and its working mechanism can be explained as follows: one Metglass was fixed at base, and another cap was stressed by NdFeB magnets; when applying AC magnetic field HAC along longitudinal (or 1) direction, the Metglass layer will be induced an extension strain along 1 direction due to magnetostriction effect; because of flexural motion in cymbal structure [18], the loaded proof mass M is also forced to move along 3 direction with an acceleration a; According to equation of F = M*a, the proof mass would generate 3-direciton inertial force under 1-direction magnetic field; the induced inertial force finally is transferred to piezoelectric plate along 1 direction via the cymbal structure with a force amplification factor N. Therefore, a large induced ME voltage is expected via d31 effect. Note that external mechanical force F or vibrations in environment can also induce an inertial/impact force acting on the loaded proof mass and induce output voltage via direct piezoelectric effect. It should be pointed that the extensional deformation of one ceramics plate is more uniform compared to bending deformation in a bimorph structure [16,19], which will allow it to produce a more stable output voltage. As illustrated in Fig. 1(b), a magnetic moment effect originated from interaction between HAC and magnet NdFeB could also induce vibration of top cap along 3 direction, which would be positive to improve the output power of MME energy harvester [15].
2. Experimental The magneto-mechano-electric (MME) energy harvester was fabricated by using one thickness-poled PZT-5 ceramic plate (Kunshan PanTe Co., Ltd., China,) and two rectangular metal caps each consisting of 12-layer magnetostrictive Metglass (FeBSiC, 2605SA1) foils. The piezoelectric ceramic plate operating in d31 mode was sandwiched between two Metglass caps in thickness direction with epoxy resin (to bond them together). And the cavity distance from piezoelectric ceramics plate to metglass cap is 6 mm. The sizes of ceramic plate are 60 mm in length, 20 mm in width and 0.2 mm in thickness. The dimension of each Metglass foil is 120 mm in length, 20 mm in width and 0.025 mm in thickness. Some epoxy resin was coated on two sides of Metglass caps to prevent electric leakage. Then, an AC magnetic field was coaxially generated by using a home-made solenoid coil powered by a Function/Arbitrary Waveform Generator (33522, Agilent, USA) and a power amplifier. And the AC magnetic field strength was calculated according to the output current I from power amplifier. The DC magnetic field was provided by magnets of NdFeB loaded on the top of one Metglass cap. The ME coupling coefficient of the magnetic energy harvester was calculated through VRMS /(tPZT -5 · HAC ), where VRMS , tPZT -5 , and HAC are output voltage (in RMS), thickness of the piezoelectric layer, and external AC magnetic field intensity (in RMS), respectively. The induced open-circuit voltages from piezoelectric phase (PZT-5 ceramics) were measured with an oscilloscope (Keysight MSOX4024A) under varying AC magnetic field.
3.3. Simulated results of MME energy harvester Fig. 2(a) further shows the extensional deformation modeling of the cymbal structure MME energy harvester under AC magnetic field HAC excitation (by using finite element analysis (FEA), Comsol software). Fig. 2(b) shows the FEA simulated HAC induced acceleration a at resonance frequency according to the
Fig. 1. (a) schematic diagram and structure of MME energy harvester, (b) diagram of work mechanism in the proposed MME energy harvester. 2
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Fig. 2. FEA modeling results of the rectangular cymbal structure under AC magnetic field excitation, (a) HAC -induced acceleration and deformation at first vibration model, and (b) acceleration a as a function of HAC for a loaded proof mass M (= 20 gf) at resonance.
pizomagnetic-piezoelectric analogy and a given piezomagnetic coefficient d33,m =2 ppm/Oe [12]. It is clear seen that the maximum vibration acceleration value of the loaded proof mass M (= 20 gf) is about 32 m/s2 (∼3.2 g) under 1 Oe AC magnetic field excitation. The HAC -induced acceleration a produces an inertial force (F(t) = Ma) acting on the magnetic mass and then an axial dynamic tension or pressing force F1 (t) against the piezoelectric plate via two laminated cymbal structured Metglas layers. According to the geometric parameter of the cymbal structure, F1 (t) can be found as F1 (t) =F(t)N=MaN
Fig. 3. (a) open-circuit peak-peak output voltage under varying HAC and (b) ME voltage coefficient of MME energy harvester as a function of excitation frequency.
3.4. Measured results of MME energy harvester Fig. 3(a) shows the measured open-circuit peak-peak output voltage (Vpp ) from PZT-5 ceramic in MME energy harvester as a function of excitation frequency under HAC with varying amplitude of 1, 3 and 5 Oe. It can be seen that higher excitation magnetic field HAC induces a higher ME voltage, and ME voltage reaches its maximum value of 6.2 V under HAC =5 Oe at resonance frequency of ∼180 Hz. Fig. 3(b) further shows ME voltage coefficient ˛ME of the MME harvester as a function of excitation frequency under HAC =1 Oe, and the maximum value of ˛ME is around 48 V/cm Oe at resonance frequency of 180 Hz. Compared with the calculated value of 148.8 V/cm Oe, which is about 3 times difference with the observed ME coupling coefficient in MME device due to (i) non optimum DC magnetic bias, and (ii) mechanical load effect of magnetic mass. These values are comparable to that of a bimorph structured magnetoelectric energy harvesters [20]. Fig. 4(a–i) shows the output ME voltage waveform of MME energy harvester under varying HAC excitation amplitude of 1, 3, 5 and 7 Oe at resonance frequency of 180 Hz. The peak-peak output voltage of MME energy harvester increases with excitation magnetic field amplitude. Fig. 4(a-ii) further shows the enlarged output ME voltage waveform of the harvester under HAC =1 Oe, and a quite stable voltage waveform is found. Fig. 4(b) characterizes the durability of the MME energy harvester for long-cycle opera-
(1)
where N = 1/tan is a force amplification factor of the cymbal structure. Clearly, designing a suitable angle in cymbal structure (see Fig.1 (a)) will result in an amplified force applied to the piezoelectric plate. It should be noted that although the magnetic mass M also applies a force to the piezoelectric plate, but it can be regarded as only a bias force. In this case, the induced voltage Vout from piezoelectric ceramic plate can be expressed as: Vout = g31 tF1 /Sp
(2)
where, g31 is piezoelectric voltage coefficient, t and Sp are the thickness and cross-sectional area of the piezoelectric ceramic plate, respectively. According to Eq. 2, the HAC -induced voltage Vout is about 3 V at resonance frequency of first vibration model, and correspondingly, its ME coupling coefficient ˛ME (= Vout /tPZT -5 · HAC ) at resonance is 148.8 V/cm Oe. We will see that the simulated results are about three times higher than measured values due to the ideal model. 3
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Fig. 4. (a-i) the time line of output voltage waveform generated by MME energy harvester under varying HAC excitation, (b-i) durability test over 47,500 working cycles under HAC of 8 Oe; (a-ii) and (b-ii) enlarging voltage waveforms.
Fig. 5. The generated power (a) and current (b) of MME energy harvester as a function of load resistance under varying HAC excitation, (c) photograph of measurement setup, (d) photograph of 10 LEDs driven by the MME energy harvester.
tion. It is clear seen that under HAC of 8 Oe after 47,500 working cycles, the output voltage waveform of the MME harvester still keep stable: the time line of peak voltage maintains flat, implying there is no any observed performance declined. The cymbal structure is more symmetric and compact, and the excited longitudinal mode deformation in piezoelectric ceramic plate is also more uni-
form in comparison to the bimorph structure operating in bending mode [16,19]; therefore, cymbal structure could avoid the bending fatigue effect of PZT ceramic plate. According to the relationship of Pp = Vpp 2 /RL , the peak-peak output power Pp of the MME harvester for a load resistance RL can be estimated. And peak-peak current was calculated based on 4
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Ohm’s law. Fig. 5 (a) and (b) show peak-peak output power Pp and peak-peak output current Ipp as a function of RL under varying AC magnetic field HAC excitation at resonance frequency of 180 Hz. It is clearly seen that both Pp and Ipp increase as HAC , and the maximum peak-peak output power Pp and Ipp under HAC =8 Oe are about 5.7 mW and 2.3 mApp , respectively, for an optimized load resistance of 5.6 k. Here, we define power density of MME energy harvester as the ratio of output power value to piezoelectric phase volume. The corresponding power density of 5.1 mW cm−3 at 7 Oe is comparable with those of cantilever type MME harvester using a low-loss PMN-PZT piezoelectric single crystal corresponding to 9.3 mW cm−3 [14]. The high peak-peak output power can be ascribed to following reasons: (i) the amplified piezoelectric coefficient deff of the cymbal structure, (ii) inertial force effect of the loaded magnet as proof mass, and (iii) the relative lower internal resistance of the non-laminated ceramic plate in the MME energy harvester. Finally, the MME energy harvester was used to drive lightemitting diodes (LEDs) with a full wave rectifying bridge, see Fig. 5(c) for measurement setup. It can be seen in Fig. 5(d) that under AC magnetic field excitation, the MME energy harvester could light up 10 LEDs stably in real time, indicating well working performance and its potential to be used as micro-energy source of wire-less sensor networks in magnetic field noise or mechanical vibration noise circumstance.
References [1] V. Annapureddy, S.-M. Na, G.-T. Hwang, M.G. Kang, R. Sriramdas, H. Palneedi, et al., Exceeding milli-watt powering magneto-mechano-electric generator for standalone-powered electronics, Energy Environ. Sci. 11 (2018) 818–829. [2] H. Vocca, I. Neri, F. Travasso, L. Gammaitoni, Kinetic energy harvesting with bistable oscillators, Appl. Energy 97 (2012) 771–776. [3] Y. Tian, C.Y. Zhao, A review of solar collectors and thermal energy storage in solar thermal applications, Appl. Energy 104 (2013) 538–553. [4] Q. Dong, Y. Fang, Y. Shao, P. Mulligan, J. Qiu, L. Cao, et al., Electron-hole diffusion lengths & 175 m in solution-grown CH3 NH3 PbI3 single crystals, Science 347 (2015) 967. [5] M.G. Kang, R. Sriramdas, H. Lee, J. Chun, D. Maurya, G.T. Hwang, et al., High power magnetic field energy harvesting through amplified magneto-mechanical vibration, Adv. Energy Mater. 8 (2018) 1703313. [6] C. Xu, B. Ren, W. Di, Z. Liang, J. Jiao, L. Li, et al., Cantilever driving low frequency piezoelectric energy harvester using single crystal material 0.71Pb(Mg1/3 Nb2/3 )O3 -0.29PbTiO3 , Appl. Phys. Lett. 101 (2012) 033502. ´ Wireless [7] A. Kurs, A. Karalis, R. Moffatt, J.D. Joannopoulos, P. Fisher, M. Soljaˇcic, power transfer via strongly coupled magnetic resonances, Science 317 (2007) 83. [8] X. Wei, Z. Wang, H.Je. Dai, A Critical Review of Wireless Power Transfer via Strongly Coupled Magnetic Resonances, 7, 2014, pp. 4316–4341. [9] Z. Chu, M. PourhosseiniAsl, S. Dong, Review of multi-layered magnetoelectric composite materials and devices applications, J. Phys. D 51 (2018) 243001. [10] Z. Chu, Z. Yu, M. PourhosseiniAsl, C. Tu, S. Dong, Enhanced low-frequency magnetic field sensitivity in magnetoelectric composite with amplitude modulation method, Appl. Phys. Lett. 114 (2019) 132901. [11] S. Dong, J. Zhai, J.F. Li, D. Viehland, S. Priya, Multimodal system for harvesting magnetic and mechanical energy, Appl. Phys. Lett. 93 (2008) 103511. [12] Z. Chu, H. Shi, W. Shi, G. Liu, J. Wu, J. Yang, et al., Enhanced Resonance Magnetoelectric Coupling in (1-1) Connectivity Composites, Adv. Mater. 29 (2017) 1606022. [13] Z. Chu, V. Annapureddy, M. PourhosseiniAsl, H. Palneedi, J. Ryu, S. Dong, Dual-stimulus magnetoelectric energy harvesting, MRS Bull. 43 (2018) 199–205. [14] V. Annapureddy, M. Kim, H. Palneedi, H.-Y. Lee, S.-Y. Choi, W.-H. Yoon, et al., Low-Loss Piezoelectric Single-Crystal Fibers for Enhanced Magnetic Energy Harvesting with Magnetoelectric Composite, Adv. Energy Mater. 6 (2016) 1601244. [15] G. Liu, P. Ci, S. Dong, Energy harvesting from ambient low-frequency magnetic field using magneto-mechano-electric composite cantilever, Appl. Phys. Lett. 104 (2014) 032908. [16] H.W. Kim, A. Batra, S. Priya, K. Uchino, D. Markley, R.E. Newnham, et al., Energy harvesting using a piezoelectric “Cymbal” transducer in dynamic environment, J. Appl. Phys. 43 (2004) 6178–6183. [17] J.F. Fernandez, A. Dogan, Q.M. Zhang, J.F. Tressler, R.E. Newnham, Hollow piezoelectric composites, Sens. Actuators A Phys. 51 (1995) 183–192. [18] X. Gao, J. Wu, Y. Yu, Z. Chu, H. Shi, S. Dong, Giant piezoelectric coefficients in relaxor piezoelectric ceramic PNN-PZT for vibration energy harvesting, Adv. Funct. Mater. 28 (2018) 1706895. [19] J. Yang, Z. Li, X. Xin, X. Gao, X. Yuan, Z. Wang, et al., Designing electromechanical metamaterial with full nonzero piezoelectric coefficients, Sci. Adv. 5 (2019), eaax1782. [20] Y. Zhou, D.J. Apo, S. Priya, Dual-phase self-biased magnetoelectric energy harvester, Appl. Phys. Lett. 103 (2013) 192909.
4. Conclusion In summary, we designed and fabricated a magneto-mechanoelectric (MME) energy harvester with a laminated rectangular cymbal structure consisting of two multilayer Metglass caps and a piezoelectric ceramic plate. The magnetic field induced voltage in the MME energy harvester was predicted by using FEA. Experimental results show that under AC magnetic field excitation of 8 Oe, the MME energy harvester can generate the maximum peak-peak output power of 5.7 mW and peak-peak current of 2.3 mApp for a matching load resistance of 5.6 k. The generated power density of 5.1 mW cm−3 at at Hac =7 Oe, is even comparable with previous reports about MME energy harvester using a low-loss PMN-PZT piezoelectric single crystal. It still exhibits stable working performance after 47,500 working cycles. Higher output power is expected to be obtained by further optimizing the structure and material parameters of both Metglass and piezoelectric ceramic. The proposed MME energy harvester has potential to be used for wireless sensors and other related micro-energy smart electronics.
Biographies Data statement Zhonghui Yu is a graduate student in the Department of Materials Science and Engineering in the College of Engineering at Peking University, China. He received his B.Sc. in Materials Science and Engineering from Hubei University of Wuhan, China, in 2018. His current research focuses on piezoelectric materials, magnetic field sensors, and energy harvesters.
The data that support the findings of this study are available from the corresponding author upon reasonable request. Declaration of Competing Interest
Zhaoqiang Chu is a Ph.D candidate at Department of Materials Science & Engineering of the College of Engineering in Peking University. He received his M.S. degree in material science from University of Science and Technology Beijing (USTB), Beijing, China, 2015. He has been working on Magneoelectric and Piezoelectric Materials, Magnetic Sensors and Energy Harvesters in Prof. Dong’s group since 2015.
The authors declare that they have no conflict of interest. Acknowledgments
Jikun Yang is currently pursuing the Ph.D. degree in advanced materials and mechanics from Peking University, Beijing, China. He received the B.E. degree in physics from University of Science and Technology Beijing, China, in 2016.His research interests include piezoelectric materials and devices, metamaterials and 3D printing ceramics.
This work was supported by the National Natural Science Foundation of China (Grant Nos 51772005, 51132001) and Xin’ao Company.
Mr. MohammadJavad PourhosseiniAsl was born in Khorramabad, Iran, in 1987. He was awarded the B.Sc. and M.Sc. in Materials Science and Engineering in 2011 and 2014, respectively. He is a Ph.D. candidate majoring in advanced materials and mechanics at Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, China. His current research interests include piezoelectric and magnetic materials, magnetoelectric (ME) composite, energy harvesting, energy conversion, multi-functional materials and development of ME sensors and gyrators.
Appendix A. Supplementary data Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.sna.2020. 112400. 5
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Xiaoting Yuan is currently pursuing the Ph.D. degree in advanced materials and mechanics from Peking University, Beijing, China. Her research interests include piezoelectric materials and devices, metamaterials and 3D printing ceramics.
Tsinghua University, China. Dr. Dong was a research associate at Materials Research Institute, Pennsylvania State University, State College, PA, from Jan., 2000–Dec., 2001, and a research scientist and research professor at Materials Science & Engineering, Virginia Tech, Blacksburg, VA, from Jan., 2002–May 2008. Professor Dong’s research focuses on piezoelectric ceramics and magnetoelectric composite materials, piezoelectric actuators and micromotors, magnetic sensors, smart electronic devices, and their applications. He has authored over 160 peer-reviewed papers and 30 patents. Prof. Dong was chosen as Most Cited Chinese Researchers in 2014–2019, who were regarded as most influential scientists in the world by Elsevier.
Yang Yu received Ph.D. degree in physics from Wuhan University, Wuhan, China. in 2020. His research interests include piezoelectric materials and devices. Ge Nie is an engineer in Xinao Company. Huilong Qi is an engineer in Xinao Company. Shuxiang Dong is Professor of Materials Science & Engineering at College of Engineering, Peking University, China. Professor Dong holds MSc and PhD degrees from
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