Power Storage Module Sealing for Cell Expansion and Moisture Control
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Solution Overview
Problem
Power storage modules face reduced sealing performance due to expansion, which can cause the sealing layer to peel off from current collectors, compromising the integrity of the cell.
Innovation Solution
A power storage module design featuring a stack of cells with a sealing member that has a low elastic modulus portion, allowing for deformation and maintaining sealing performance, along with grooves to direct moisture and a detecting line configuration to prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid sealing layer is used to seal the power storage cell, then sealing performance is initially good, but the sealing layer peels off when the cell expands, reducing sealing performance
Solution Approach 1:
The sealing member uses an elastic modulus lower than that of the spacer, allowing it to deform elastically when the power storage cell expands. This parameter change in stiffness enables the sealing member to accommodate volume changes without peeling off, maintaining continuous sealing performance throughout the cell's lifecycle.
Solution Approach 2:
The sealing member is designed as a flexible component with lower elastic modulus compared to the rigid spacer. This flexibility allows the sealing member to follow the expansion and contraction of the power storage cell, preventing peeling and maintaining sealing integrity under varying conditions.
2Reliability
If the sealing member is made soft to accommodate expansion, then sealing performance is maintained, but the module stiffness is reduced
Solution Approach 1:
The sealing structure employs local quality differentiation where the sealing member has low elastic modulus for flexibility and sealing, while the spacer has high elastic modulus for structural support. This spatial differentiation of material properties allows the module to simultaneously achieve soft sealing and stiff structural framework.
Solution Approach 2:
The sealing structure combines materials with different elastic moduli - a soft sealing member for compliance and a rigid spacer for structural integrity. This composite approach creates a hierarchical system where the soft sealing member provides sealing function while the rigid spacer maintains overall module stiffness and shape.
3Reliability
If a solid sealing structure is used to prevent moisture, then sealing is effective, but moisture can still flow along the stack side surfaces
Solution Approach 1:
The sealing member incorporates groove structures that create curved surfaces to redirect moisture flow. These grooves guide moisture away from critical areas and prevent direct flow along the stack side surfaces, effectively blocking the moisture intrusion path while maintaining the sealing structure.
Solution Approach 2:
The groove structures act as intermediary elements within the sealing member that intercept and redirect moisture. These grooves serve as a mediating feature between the external environment and the sealed interior, preventing moisture from directly reaching vulnerable areas while maintaining overall sealing effectiveness.
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 sealing performance by accommodating cell expansion and reducing the risk of short circuits while maintaining module stiffness and preventing moisture flow.
Implementation Method 1
a portion of the sealing member disposed on at least one of the stack side surfaces serves as a low elastic modulus portion that has an elastic modulus lower than an elastic modulus of the spacer... the sealing member, which is relatively deformable, may sufficiently deform following the deformation of the power storage cell while securing sealing performance
Data Source
AI summary
A power storage module includes: a stack including power storage cells stacked in a first direction and having stack side surfaces that extends in the first direction; and a sealing member formed in contact with the stack side surfaces. The power storage cells each includes: a first electrode including a first electrode plate having a first surface and a first active material layer formed on the first surface; a second electrode including a second electrode plate having a second surface and a second active material layer having an electrode polarity different from that of the first active material layer and formed on the second surface; and a spacer. A portion of the sealing member disposed on at least one of the stack side surfaces serves as a low elastic modulus portion that has an elastic modulus lower than that of the spacer.