Thermoplastic Polymer Current Collector for Thermal Runaway Mitigation
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Solution Overview
Problem
Existing battery pack solutions fail to effectively mitigate thermal runaway in lithium-ion batteries, particularly due to internal short-circuits, leading to potential explosions and reduced battery performance, and current thermal management systems do not adequately absorb energy dissipated during thermal runaway, posing risks to other batteries in the pack.
Innovation Solution
A metal-ion electrochemical accumulator design featuring a thermoplastic polymer current collector with conductive particles or fibers, heat-sealed to the electrochemical bundle, which melts to increase internal resistance and reduce short-circuit current in case of thermal runaway, thereby minimizing the impact on adjacent batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current collectors are used, then electrical conductivity is maintained, but thermal runaway propagation risk increases
Solution Approach 1:
The current collector uses a thermoplastic polymer matrix with embedded conductive particles/fibers instead of traditional metal foils. The key parameter change is the material composition - using polymer composite with specific glass transition temperature (Tg) and melting temperature (Tm) ranges to enable thermal response at controlled temperatures while maintaining electrical conductivity through the conductive filler network.
Solution Approach 2:
The thermoplastic polymer matrix undergoes phase transition (glass transition and melting) at specific temperatures during thermal runaway events. This phase change causes the polymer to soften and increase in viscosity, which traps the conductive particles and disrupts the conductive network, thereby increasing electrical resistance and limiting current flow during thermal abuse conditions.
2Use of energy by moving object
If metal current collectors are used, then electrical conductivity is high, but thermal management capability is insufficient
Solution Approach 1:
The current collector is formulated as a composite material combining thermoplastic polymer matrix with embedded conductive particles or fibers. This composite structure provides dual functionality: the conductive filler network maintains electrical conductivity while the polymer matrix contributes thermal management through its phase transition behavior, creating a material that simultaneously addresses both electrical and thermal requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the risk of thermal runaway propagation across the battery pack by rapidly increasing internal resistance during overheating events, enhancing safety and performance by minimizing the impact of thermal runaway on other batteries.
Implementation Method 1
A metal-ion electrochemical accumulator design featuring a thermoplastic polymer current collector with conductive particles or fibers, heat-sealed to the electrochemical bundle, which melts to increase internal resistance and reduce short-circuit current in case of thermal runaway
Implementation Method 2
A metal-ion electrochemical accumulator design featuring a thermoplastic polymer current collector with conductive particles or fibers
Data Source
Figure 1~3
Figure 4~5B
Figure 6A~7
AI summary
Metal-ion electrochemical accumulator incorporating a current collector formed by a thermoplastic polymer disc loaded with electrically conductive particles and/or fibers. The invention essentially consists of providing, in a rigidly packaged accumulator (casing), at least one "intermediate" current collector, that is to say arranged between the electrochemical bundle of the accumulator and one of its output terminals, a part of which is in the form of a plate (cylindrical disc) made of thermoplastic polymer loaded with electrically conductive particles and/or fibers.