Bipolar Power Storage Module Buffer Region for Gas Pocket Stability
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Solution Overview
Problem
In power storage modules, internal and external differential pressures can cause the outermost electrode to deform inwardly, reducing the volume of the gas pocket region where gases produced during charging and discharging are accommodated.
Innovation Solution
A power storage module design that includes a buffer region formation member to absorb differential pressures, preventing the uncoated portions of the terminal electrodes from coming into contact and maintaining the volume of the gas pocket by forming a buffer region outside the electrode laminate, which overlaps the region sealed at a pressure lower than atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power storage module is sealed with the electrode laminate under atmospheric pressure, then the sealing is effective, but the outermost electrode deforms inwardly when the internal pressure drops below atmospheric pressure, reducing the gas pocket volume
Solution Approach 1:
The invention performs preliminary action by forming a buffer region between the sealing portion and the electrode laminate before the power storage module is sealed. This buffer region is created by disposing a buffer region formation member that extends from the sealing portion toward the electrode laminate, establishing a protective space that prevents electrode deformation and maintains gas pocket volume before any pressure differential occurs.
Solution Approach 2:
The invention introduces an intermediary element - the buffer region formation member - between the sealing portion and the electrode laminate. This intermediary creates a buffer region that acts as a mediator to absorb pressure differentials and prevent direct contact between the sealing portion and the electrode laminate, thereby maintaining both sealing effectiveness and gas pocket volume.
2Quantity of substance
If the gas pocket region is made larger to accommodate more gas, then gas accommodation capacity increases, but the electrode laminate occupies more space and the module size increases
Solution Approach 1:
The invention utilizes another dimension by creating a buffer region in the space between the sealing portion and the electrode laminate, effectively using the depth dimension rather than expanding the lateral dimensions. This allows the gas pocket volume to be maintained or increased without proportionally increasing the overall module size, as the buffer region is formed within the existing structural envelope.
Data Source
AI summary
A power storage module includes an electrode laminate having a plurality of bipolar electrodes, a positive terminal electrode, and a negative terminal electrode, a sealing portion, and a buffer region formation member that forms a sealed buffer region. Each bipolar electrode has a current collector, a positive electrode active material layer, and a negative electrode active material layer. Positive terminal electrode has a positive electrode current collector foil and positive electrode active material layer. Negative terminal electrode has a negative electrode current collector foil and negative electrode active material layer. Sealing portion seals a region formed between a positive electrode uncoated portion and a negative electrode uncoated portion in a state where becomes a pressure within region is lower than atmospheric pressure. Buffer region formation member forms a buffer region at a position overlapping region in a stacking direction.