Battery Cell Wrap and Heat Plate Layout for Thermal Runaway Containment
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Solution Overview
Problem
Battery packs containing electrochemical cells, such as lithium-ion cells, are prone to thermal runaway, which can lead to a cascading effect causing adjacent cells to also enter thermal runaway, resulting in power interruption and collateral damage due to uncontrolled heat propagation.
Innovation Solution
A cell assembly design featuring an electrochemical cell with an outer wrap having a flame barrier and a tape strip for securement, along with heat plates and a polymeric resin that ruptures to direct gases away during off-gassing events, effectively isolating and containing thermal runaway within individual cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal barrier elements are used to prevent thermal runaway propagation, then safety is improved, but device complexity increases
Solution Approach 1:
The patent employs thin film thermal barrier elements that wrap around individual electrochemical cells. These flexible thin films provide thermal isolation between adjacent cells, preventing thermal runaway propagation while maintaining a compact battery pack design. The thin film approach minimizes added complexity compared to rigid thermal barrier structures.
Solution Approach 2:
The thermal barrier element acts as an intermediary between adjacent electrochemical cells. It is positioned in the thermal pathway between cells, absorbing or blocking heat transfer during thermal runaway events. This intermediary structure prevents direct thermal coupling between cells while maintaining electrical connectivity through separate pathways.
2Temperature
If spacer assemblies are used to maintain cell position and minimize thermal effects, then thermal isolation is improved, but device complexity increases
Solution Approach 1:
The patent combines the thermal barrier function and mechanical positioning function into a single integrated structure. The thermal barrier element simultaneously serves as both the thermal isolation layer and the structural component that maintains cell positioning within the battery pack, eliminating the need for separate spacer assemblies.
Solution Approach 2:
The thermal barrier element is designed to perform multiple functions: thermal isolation, mechanical support, and positional stabilization of electrochemical cells. This multi-functional design reduces overall device complexity by consolidating what would otherwise require separate dedicated components for each function.
3Object-affected harmful factors
If shielding at cell level is provided to inhibit thermal energy flow, then thermal runaway propagation is reduced, but manufacturing complexity increases
Solution Approach 1:
The thermal barrier elements are designed as simple, inexpensive components that can be easily manufactured and applied to each cell. The use of readily available materials like thin films or foam layers simplifies the manufacturing process compared to complex engineered shielding structures, making the solution scalable for mass production.
Solution Approach 2:
The shielding is implemented using flexible thin films that can be wrapped around individual cells in a simple manufacturing process. This approach eliminates the need for precision-fitted rigid shields, allowing for easier assembly and reduced manufacturing complexity while maintaining effective thermal isolation.
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 mitigates thermal runaway propagation by providing thermal containment and gas direction, preventing adjacent cells from overheating and reducing the risk of combustion, ensuring safer and more reliable battery pack operation.
Implementation Method 1
a first portion having a flame barrier that engages the forward wall of the electrochemical cell
Implementation Method 2
a polymeric resin that ruptures to direct gases away during off-gassing events
Data Source
AI summary
A cell assembly group is provided, comprising: a plurality of cell assemblies, each cell assembly including an electrochemical cell and an outer wrap surrounding the cell; a foam sheet positioned adjacent one side of one cell assembly; a plurality of heat plates, each heat plate being positioned between two cell assemblies; and at least one spacer positioned between one heat plate and one cell assembly. Each outer wrap of each cell assembly of the plurality of cell assemblies includes a body having an inner surface that engages a rearward wall of the electrochemical cell of the cell assembly, a first portion having a flame barrier that engages a forward wall of the electrochemical cell of the cell assembly, and a second portion that engages an outer surface of the first portion.