Battery Cell Expansion Panel for Cooling and Flame Barrier
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Solution Overview
Problem
Battery packs in electric and hybrid electric vehicles face challenges with heat buildup and flame propagation due to the close proximity of cells, which can lead to thermal runaway and fire spread, especially when pouch cells or prismatic cells expand and contract, lacking effective cooling and pressure management.
Innovation Solution
An expansion panel comprising two plates with a spring layer between them, which applies a predetermined pressure to battery cells, provides a flame barrier, and allows for active cooling by accommodating cell expansion and contraction, using a metallic or non-metallic spring mechanism to maintain pressure and facilitate heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cells are placed in close proximity to improve packing efficiency and reduce weight, then energy density is improved, but heat buildup and flame propagation risk increase
Solution Approach 1:
The expansion panel is divided into multiple functional layers: a flame barrier layer that prevents flame propagation, a spring layer that provides compression force, and a cooling fluid passage system that actively removes heat. This segmentation allows each layer to address specific harmful effects while working together to maintain cell proximity for high packing efficiency.
Solution Approach 2:
The expansion panel acts as an intermediary component between adjacent battery cells. It includes a cooling fluid passage that circulates coolant between cells to actively remove heat, and a flame barrier layer that prevents flame propagation. This intermediary structure enables close cell spacing while mitigating heat buildup and fire spread risks.
2Duration of action of stationary object
If expansion pads are used to accommodate cell expansion and contraction, then cell life is extended, but flame barrier protection is reduced
Solution Approach 1:
The expansion panel uses a composite structure combining a flame barrier layer (made from flame-retardant material) with a spring layer (compressible element). This composite design provides both mechanical accommodation for cell expansion/contraction and thermal protection against flame propagation, overcoming the limitation of traditional single-material expansion pads.
Solution Approach 2:
The expansion panel is segmented into distinct functional layers: the flame barrier layer that prevents flame spread and the spring layer that provides compression force to accommodate cell dimensional changes. This segmentation allows simultaneous achievement of fire protection and mechanical compliance.
3Stress or pressure
If compression force is applied to maintain cell pressure, then cell performance is optimized, but heat dissipation is hindered
Solution Approach 1:
The cooling fluid passage system acts as an intermediary heat transfer medium between the compressed cells and the external cooling system. Coolant circulates through the passage, actively removing heat from the cell surfaces while the expansion panel maintains compression force, thus decoupling the pressure application function from heat dissipation function.
Solution Approach 2:
The expansion panel incorporates a cooling fluid passage that utilizes fluid circulation (hydraulic/pneumatic principle) to actively remove heat from between the compressed battery cells. This fluid-based cooling system efficiently dissipates heat while allowing the mechanical compression force to be maintained independently.
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 expansion panel effectively manages pressure and cooling, reducing the risk of thermal runaway and flame propagation while maintaining surface pressure on battery cells, enhancing the safety and efficiency of battery packs.
Implementation Method 1
The spring layer may be arranged to store elastic potential energy when the expansion panel is compressed. This may be achieved through deformation of the spring layer to create an opposing force.
Implementation Method 2
In use, pouch cells may expand and contract. It is therefore known to provide an expansion pad (sometimes referred to as a compression pad) between adjacent pouch cells.
Data Source
AI summary
An expansion panel for installation against a battery cell in a battery assembly is disclosed. The expansion panel comprises two plates, wherein at least one plate is arranged to face the battery cell, and a spring layer between the two plates. The expansion panel may be able to provide pressure to the battery cell, while at the same time helping with cell cooling. The expansion panel may also provide a flame barrier, which may offer thermal runaway protection.