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Wang et al. Soft Sci 2024;4:32 https://dx.doi.org/10.20517/ss.2024.15 Page 21 of 27

approach involves using material systems with inherent mechanical flexibility, such as poly(3,4-ethylene
[97]
dioxythiophene)(styrene sulfonate) (PEDOT:PSS), poly(3-ethylthiophene) (P3HT) , and two-dimensional
[98]
materials such as silver sulfide (Ag S) .
2
Despite the clear advantages of flexible thermoelectric cooling technology in enhancing device flexibility
and comfort, its application in BTMS remains limited. Current research primarily focuses on the
fundamental properties of flexible thermoelectric materials and their use in wearable devices. For example,
Ding et al. developed a flexible PCM radiator that combines polyamide, graphene, and silicone rubber, and
applied it to TECs . This TEC can lower body temperature by 11.21 K within 30 s and maintain the
[92]
reduced temperature for at least 300 s, effectively enhancing the heat dissipation performance of TECs.
Zhang et al. designed a wearable TEC with a dual-layer heat dissipation unit composed of hydrogel and
[99]
nickel foam, which demonstrated excellent flexibility . When operated at an input current of 0.3 A, it
achieved a significant and sustained temperature drop of approximately 10 K. In practical tests, the device
using AA batteries achieved a stable temperature reduction of 7 K. Wei et al. designed a flexible heat
dissipation system for a pin-fin soft-cover wearable device. This system simultaneously achieves power
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generation and cooling effects . As a TEG, it delivers a power density of 6.63 μW·cm on a stationary
[100]
human body at an ambient temperature of 293 K. As a cooler, it can lower the skin temperature by 1.5 K.
Mukaida et al. designed and fabricated a polymer-based thermoelectric module for charging lithium-ion
batteries . A 5-gram device can fully charge a commercial lithium-ion battery (Nichicon SLB03070LR35)
[101]
within two days. Further investigation and validation are needed to fully realize the potential of flexible
thermoelectric cooling technology in BTMS.

CONCLUSION AND OUTLOOK
Effective battery thermal management technology is essential for the widespread adoption of lithium-ion
batteries, with future trends in BTMS cooling technology expected to emphasize improved efficiency,
environmental friendliness, and cost-effectiveness. An efficient BTMS should possess high precision, real-
time predictability, and controllability of states. Existing simulation software provides robust support for the
development of battery thermal management technology. TECs used for battery thermal control represent a
new competitor in the realm of electric vehicles. TECs operate by converting voltage into temperature
differences, and temperature can be easily regulated by changing the direction of current flow. TECs offer
advantages such as relative quietness, stability, and reliability, and they have begun to emerge in
prominence within power BTMS. However, their cooling efficiency is relatively low, necessitating their
combination with other technologies. Based on the discussion of air cooling, liquid cooling, PCM cooling,
heat pipe cooling, and composite cooling technologies utilizing thermoelectric refrigeration, the following
conclusions and prospects can be drawn:

1. Combining TEC with air cooling: BTMS utilizing thermoelectric refrigeration combined with air cooling
can effectively address the issue of uneven temperature distribution among battery cells in air cooling
technology. This integration enhances the system’s heat dissipation efficiency, stability, and energy
utilization, offering the potential to drive advancements in electric vehicles, electronic devices, and other
fields.

2. Combining TEC with liquid cooling: BTMS based on thermoelectric refrigeration combined with liquid
cooling offers the advantages of precise temperature control through TEC while maintaining the high
thermal conductivity and cooling efficiency of liquid cooling. This integration enables a more streamlined
and compact liquid cooling system, reducing reliance on complex structures and components, and thereby
lowering assembly and maintenance costs. It also enhances system reliability and stability by effectively