Pouch Cell Battery Pack Venting to Limit Thermal Propagation
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Solution Overview
Problem
Pouch battery cells prone to short-circuiting and thermal propagation during thermal runaway due to erratic smoke dispersion, posing significant safety hazards.
Innovation Solution
A battery pack design featuring a lower housing, cell stack body, foaming adhesive, cover, and partition structure that defines an exhaust channel to direct high-temperature smoke away from the tab sides, using foaming adhesive for stable connection and partition structures to prevent short-circuiting and thermal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pouch cells are used in the battery pack, then the battery pack can achieve high energy density and flexibility, but when thermal runaway occurs, the high-temperature smoke exhibits erratic dispersion which can lead to short-circuiting and thermal propagation at the tab
Solution Approach 1:
The invention divides the battery pack into multiple independent compartments using partition walls. Each compartment contains individual pouch cells and has its own exhaust channel. When thermal runaway occurs in one compartment, the partition walls prevent smoke and heat from propagating to other compartments, isolating the thermal event. The exhaust channels are specifically designed to direct smoke away from tab areas, preventing short-circuiting while maintaining the high energy density benefits of pouch cells.
Solution Approach 2:
The invention introduces foaming adhesive as an intermediary material between the pouch cells and the housing structure. This foaming adhesive serves multiple functions: it provides thermal insulation to prevent heat transfer to adjacent cells, acts as a fire barrier to slow thermal propagation, and secures the cells in position. The intermediary nature of this material protects the tab areas from direct exposure to high-temperature smoke while maintaining the structural integrity and energy density of the pouch cell configuration.
2Device complexity
If traditional battery pack structures are used without dedicated exhaust channels, then the structure is simpler, but high-temperature smoke from thermal runaway disperses erratically causing safety hazards
Solution Approach 1:
The invention incorporates exhaust channels and partition walls into the battery pack structure during the manufacturing process, before thermal runaway can occur. These safety features are pre-configured to direct smoke flow away from tab areas and isolate thermal events. The exhaust channels are positioned and sized in advance to ensure proper smoke evacuation, and the partition walls are pre-installed to create independent compartments. This preliminary action ensures that when thermal runaway occurs, the safety mechanisms are already in place, maintaining both structural organization and high safety performance without requiring complex active control systems.
3Ease of manufacture
If cells are fixed directly to the housing without foaming adhesive, then the manufacturing process is simpler, but the cells are less stable and more prone to movement which can cause short-circuiting
Solution Approach 1:
The invention utilizes the parameter changes that occur when foaming adhesive cures - specifically the volume expansion and phase change from liquid to foam. The adhesive is applied in a liquid state for easy application, then as it cures and expands, it fills gaps and creates a stable, cushioning bond between the pouch cells and housing. This parameter change provides both simplicity of application (similar to direct fixing) and superior stability (exceeding direct fixing), while the foam structure also provides thermal insulation and vibration damping to prevent cell movement and short-circuiting.
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
Enhances safety by stabilizing the cell stack and efficiently exhausting high-temperature smoke, reducing the risk of short-circuiting and thermal propagation, thereby improving the safety performance of the battery pack.
Implementation Method 1
a foaming adhesive, the foaming adhesive filled and connected between a tab side of the cell stack body and the lower housing
Implementation Method 2
When cells undergo thermal runaway, should the high-temperature smoke be expelled from the tab sides of the cells, there exists a significant probability of short-circuiting and the initiation of thermal propagation at the tab
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A battery pack includes a lower housing (1), a cell stack body (2), a foaming adhesive (3), a cover (4), and a partition structure (5). The lower housing has an upper opening and an exhaust portion (121). The cell stack body includes multiple stacked pouch cells (21), and is disposed in the lower housing, with the bottom side of the cell stack body connected and fixed to the baseplate (11) of the lower housing. The foaming adhesive is filled and connected between the tab side of the cell stack body and the lower housing. The cover is located on the top side of the cell stack body and covers the upper opening of the lower housing. The partition structure is clamped between the cover and the cell stack body.