Safe positive temperature coefficient composite cathode for lithium ion battery

Zhong, Hai; Kong, Chan; Zhan, Hui; Zhan, Caimao; Zhou, Yunhong

doi:10.1016/j.jpowsour.2012.05.015

Cited by 59 publications

(36 citation statements)

References 19 publications

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“…Traditional soft thermal sensors used in soft artificial intelligence robots are based on semi‐crystalline polymers, such as low molecular weight polyethylene, and conductive materials such as carbon black. Due to the high coefficient of linear thermal expansion of polyethylene (2 × 10 −4 m K −1 ), the volume of polymers expands upon heating, which results in the increase of space in conductive carbon black . The increase of space leads to increase in thermal sensor resistance, displaying their thermal response .…”

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confidence: 99%

Soft Thermal Sensor with Mechanical Adaptability

et al. 2016

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A soft thermal sensor with mechanical adaptability is fabricated by the combination of single-wall carbon nanotubes with carboxyl groups and self-healing polymers. This study demonstrates that this soft sensor has excellent thermal response and mechanical adaptability. It shows tremendous promise for improving the service life of soft artificial-intelligence robots and protecting thermally sensitive electronics from the risk of damage by high temperature.

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confidence: 99%

Soft Thermal Sensor with Mechanical Adaptability

et al. 2016

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“…Thermal instability is the key element that determines an LIB's safety. Generally, an obvious temperature increase is a clear signal that can be sensed in case of an early stage abnormality . For this reason, external PTC resistors, which undergo a sharp increase in electrical resistance as the temperature goes higher, are widely used as a safety assurance for LIBs that can reversibly reduce/cut off the battery current output upon electrical abuse .…”

Section: New Smart Materials With Thermal Responding Functionsmentioning

confidence: 99%

“…Due to their suitable Curie temperature and compatibility with current LIB systems, various polymer‐PTC‐based cathode materials have been developed and demonstrated their feasibility. These polymer PTC composites include high‐density polyethylene (PE), particle polyvinylidene fluoride (PVDF), poly(methyl methacrylate) (PMMA), ethylene vinyl acetate (EVA), etc. Generally, in this strategy, the polymers, carbon black, and cathode active materials are mechanically mixed, which makes it hard to form a conductive network between the active components and the PTC, thus leading to less promising rate capability of the electrodes and batteries.…”

Section: New Smart Materials With Thermal Responding Functionsmentioning

confidence: 99%

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Smart Materials and Design toward Safe and Durable Lithium Ion Batteries

et al. 2019

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Smart electrochemical energy storage devices are devices that can operate autonomously to some extent. Although the conventional electrochemical energy storage devices, e.g., the commonly used lithium‐ion batteries (LIBs), may be externally monitored in terms of their voltage and current output to reflect the state of health for the devices, it is extremely important to exploit materials and devices that are intrinsically smart enough to be capable of rapidly self‐detecting and responding to faults, such as interior short circuits, overheating, abnormal capacity drop, and other types of mechanical/chemical damage. These “smart” features could significantly enhance the safety characteristics and durability of LIBs, which is essential for future usage. Therefore, recent achievements toward smart materials and design strategies for safer and more durable LIBs are summarized. The main categories are as follows: 1) New materials: This category mainly includes smart electrode materials with thermal/electrical/mechanical self‐response functions, and self‐response separators to suppress thermal runaway/lithium dendrite growth; 2) New chemistries: This category mainly includes electrolytes with reversible self‐protecting functions; and 3) New architectures with novel functions, such as shape‐recovery, self‐heating, and self‐monitoring. Besides the working mechanisms, the challenges that must be overcome for smart LIBs to be adopted in practical applications are also discussed.

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“…6,7 To improve the safety of LIBs, shutdown separators typically having PP (polypropylene)/PE (polyethylene) bilayer or PP/PE/PP trilayer structure are commonly used as a fail-safe device in commercial cells. [12][13][14][15] To get a better safety control for LIBs, a number of strategies such as temperature-sensitive electrode materials, 16 positivetemperature-coefficient (PTC) electrodes, [17][18][19] and thermal shutdown electrode 20,21 and electrolyte [22][23][24][25] have been proposed as a self-activating protection mechanism to prevent the overheated cells from thermal runaway. However, this type of separator oen loses control to thermal runaway in practical applications, because the difference between the melting point of PE (135 C) and PP (165 C) is only 30 C, thermal inertia aer shutdown can easily cause the cell temperature to keep going onto the melting point of PP, resulting in shrinking of separator and then internal shortcircuiting of the electrodes.…”

Section: Introductionmentioning

confidence: 99%

Temperature-responsive microspheres-coated separator for thermal shutdown protection of lithium ion batteries

Jiang

et al. 2015

RSC Adv.

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Safety issues have severely retarded the commercial applications of high-capacity and high-rate lithium ion batteries (LIBs) in electric vehicles and renewable power stations. Thermal runaway is a major cause for the hazardous behaviors of LIBs under extreme conditions. In this paper, a new thermal shutdown separator with a more reasonable shutdown temperature of $90 C is developed by coating thermoplastic ethylene-vinyl acetate copolymer (EVA) microspheres onto a conventional polyolefin membrane film and tested for thermal protection of lithium-ion batteries (LIBs). The experimental results demonstrate that owing to the melting of the EVA coating layer at a critical temperature, this separator can promptly cut off the Li + conduction between the electrodes and thus shut down the battery reactions, so as to protect the cell from thermal runaway. In addition, this type of the separator has no negative impact on the normal battery performance, therefore providing an internal and self-protecting mechanism for safety control of commercial LIBs.

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Safe positive temperature coefficient composite cathode for lithium ion battery

Cited by 59 publications

References 19 publications

Soft Thermal Sensor with Mechanical Adaptability

Soft Thermal Sensor with Mechanical Adaptability

Smart Materials and Design toward Safe and Durable Lithium Ion Batteries

Temperature-responsive microspheres-coated separator for thermal shutdown protection of lithium ion batteries

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