Prismatic Li-Ion Cell Insulation Assembly for Thermal Runaway Mitigation
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Solution Overview
Problem
Existing battery packs in electric vehicles are susceptible to thermal runaway events due to internal short circuits, which can propagate and cause cascading failures among adjacent cells.
Innovation Solution
A battery cell design incorporating an insulation assembly with a heat absorbent material enclosed by a plastic cover that releases a non-flammable liquid upon reaching a threshold temperature, reducing heat flow to the electrode assembly and inhibiting ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If battery cells are placed adjacent to each other in a battery pack, then space utilization and power output are improved, but thermal runaway can propagate to adjacent cells causing cascading failures
Solution Approach 1:
The patent divides the battery pack into isolated compartments using insulation assemblies positioned between adjacent battery cells. Each cell is segmented from its neighbors by these insulation structures, preventing thermal runaway propagation while maintaining high cell density for power output.
Solution Approach 2:
The insulation assembly acts as an intermediary barrier between adjacent battery cells. It includes heat-absorbent material and non-flammable liquid reservoirs that mediate thermal interactions, absorbing excess heat and preventing it from transferring to neighboring cells.
2Reliability
If insulation material is added between battery cells to prevent thermal runaway, then thermal safety is improved, but device complexity and space requirements increase
Solution Approach 1:
The insulation assembly merges multiple functions into a single integrated structure: thermal insulation, heat absorption, and fire suppression. The assembly combines insulation material, heat-absorbent material, and non-flammable liquid reservoirs into one compact unit that attaches to the battery cell housing.
Solution Approach 2:
The heat-absorbent material utilizes phase transition (melting) at a specific threshold temperature to absorb large amounts of heat energy. The plastic cover is designed to melt and release non-flammable liquid when temperature exceeds the threshold, providing automatic thermal protection without complex control systems.
3Reliability
If heat-absorbent material with non-flammable liquid is used in the insulation assembly, then thermal runaway mitigation is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The insulation assembly is designed to activate automatically based on temperature conditions without external control. The plastic cover melts at a predetermined threshold temperature, automatically releasing non-flammable liquid to suppress thermal runaway, eliminating the need for sensors, controllers, or complex actuation systems.
Solution Approach 2:
The non-flammable liquid is pre-stored in the insulation assembly during manufacturing, ready for immediate deployment when thermal runaway occurs. The heat-absorbent material is pre-positioned to absorb heat at critical temperatures, providing immediate protection without requiring real-time decision-making or activation sequences.
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 design effectively mitigates thermal runaway events by dissipating heat and preventing ignition, enhancing safety and stability of the battery pack.
Implementation Method 1
The plastic cover is configured to shrink when a temperature of the plastic cover is above a threshold temperature
Implementation Method 2
The heat absorbent material has a non-flammable liquid stored therein... to reduce a flow of heat from outside of the housing to the electrode assembly
Data Source
AI summary
An electrical system includes a battery pack having a battery cell. The battery cell includes a housing having at least one side and forming a chamber, an electrode assembly disposed within the chamber, and an insulation assembly disposed in the chamber between the electrode assembly and the at least one side of the housing. The insulation assembly includes a heat absorbent material enclosed by a plastic cover. The heat absorbent material has a non-flammable liquid stored therein. The plastic cover is configured to shrink when a temperature of the plastic cover is above a threshold temperature, thereby releasing the non-flammable liquid from the heat absorbent material into the chamber to reduce a flow of heat from outside of the housing to the electrode assembly.