Battery Pack Thermochemical Barriers for Thermal Runaway Mitigation
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Solution Overview
Problem
Battery pack systems in electric vehicles and hybrid electric vehicles are prone to thermal runaway, where excessive heat generated by a battery cell cannot be dissipated, leading to unfavorable temperature increases and potential propagation to adjacent cells.
Innovation Solution
Incorporation of a thermochemical material within the battery pack system that undergoes an endothermic reaction at temperatures above 50°C, located either within the stack of battery cells, exterior to the cells, or adjacent to the stack, to absorb energy and inhibit thermal runaway propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If battery cells are densely packed to increase energy density, then productivity and space utilization improve, but thermal runaway propagation risk increases due to reduced separation between cells
Solution Approach 1:
A thermochemical material is introduced as an intermediary substance positioned between adjacent battery cells. This material undergoes endothermic decomposition when exposed to thermal runaway conditions, absorbing heat and preventing thermal propagation to neighboring cells. The intermediary material thus enables dense cell packing while maintaining thermal safety.
Solution Approach 2:
The thermochemical material utilizes phase transition (decomposition) at specific temperature thresholds to absorb excessive heat. The material transitions from a stable solid state to decomposed products through endothermic reactions, effectively quenching thermal runaway events and protecting adjacent cells during phase change.
2Reliability
If thermochemical material is added to mitigate thermal runaway, then safety improves, but device complexity increases due to additional components and positioning requirements
Solution Approach 1:
The thermochemical material is nested within existing battery pack structural elements such as cell holders, support plates, or spacing components. By integrating the safety material into already-present structural features, the design avoids adding separate complex subsystems while still providing thermal protection functionality.
Solution Approach 2:
The battery pack structural components are designed to serve multiple functions: providing mechanical support, maintaining cell spacing, and housing or delivering thermochemical material for thermal protection. This multi-functionality reduces overall system complexity by combining safety features with existing structural elements.
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 thermochemical material effectively absorbs energy during thermal runaway events, mitigating the spread of excessive heat to adjacent battery cells and helping to quench the thermal runaway quickly, thereby enhancing the safety and reliability of the battery pack system.
Implementation Method 1
The thermochemical material undergoes endothermic reaction at temperatures above 50° C.
Data Source
AI summary
A battery pack system for inhibiting thermal runaway includes a stack of battery cells wherein each battery cell has a first end, a second end opposite the first end, and side edges extending from the first end to the second end and wherein at least one of the side edges of each battery cell are adjacent to at least one side edge of another of the battery cells, a thermochemical material that undergoes endothermic reaction at temperatures above 50° C., the thermochemical material being located (a) within the stack of battery cells and exterior to battery cells or (b) adjacent to the stack of battery cells, or (c) both.