Bipolar Power Storage Module Reinforcement Against Electrolyte Leakage
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Solution Overview
Problem
Bipolar batteries face reliability issues due to deformation of current collectors and resin groups, leading to electrolyte leakage or breakage, especially when the negative electrode is on the outermost portion, exacerbated by the 'alkali creep' phenomenon.
Innovation Solution
An electricity-storage module design featuring stacked bipolar electrodes with a sealing body and a reinforcing body to prevent deformation, where the sealing body is welded to the electrodes' surfaces and the reinforcing body is joined to the electrodes' surfaces to enhance structural integrity, and the reinforcing body's material has greater tensile strength and Young's modulus than the sealing body's material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the negative electrode layer is located on the outermost portion to simplify structure, then manufacturing is easier, but electrolyte leakage occurs due to alkali creep phenomenon
Solution Approach 1:
A resin group is introduced as an intermediary protective layer between the negative electrode layer and the external environment. This resin group prevents direct contact of the aqueous alkali electrolyte with the outer surface, thereby blocking the alkali creep phenomenon while maintaining the simplified outermost negative electrode structure.
Solution Approach 2:
The resin group is applied in advance to the outer surface of the battery element before electrolyte leakage can occur. This preliminary protective coating prevents the alkali creep phenomenon from initiating, thereby maintaining reliability without requiring structural changes.
2Reliability
If the inner pressure rises to test battery performance, then reliability testing is improved, but deformation occurs in the current collector and resin group
Solution Approach 1:
A constraining member is introduced to apply a predetermined constraining load to the electrode stacked body in advance. This cushioning effect prevents excessive deformation when internal pressure rises during performance testing, while still allowing sufficient pressure buildup for reliable testing.
Solution Approach 2:
The constraining member modifies the mechanical parameters of the battery structure by applying a controlled compressive load. This changes the stress distribution within the current collector and resin group, preventing deformation while maintaining the ability to perform reliability testing.
3Volume of moving object
If the resin group is made thinner to reduce size, then compactness is improved, but breakage of the resin group occurs under pressure
Solution Approach 1:
The protective structure uses a composite approach combining the resin group with the constraining member. The constraining member provides enhanced mechanical strength to prevent resin group breakage, while the resin group maintains its thin profile for compactness. Together they form a composite protective system.
Solution Approach 2:
The constraining member provides beforehand cushioning support to the thin resin group, preventing it from breaking under internal pressure during battery operation or testing, thereby enabling the use of thinner resin groups for compactness.
4Stability of the object's composition
If the constraining load is increased to prevent deformation, then structural stability is improved, but the battery cannot expand to accommodate electrolyte volume changes
Solution Approach 1:
The constraining member is designed with dynamic characteristics that allow it to adapt to varying internal pressures. When pressure is low, it maintains structural stability; when pressure increases due to electrolyte volume changes, it allows controlled expansion. This dynamic response resolves the contradiction between stability and adaptability.
Solution Approach 2:
The constraining member's mechanical properties are optimized to change its rigidity based on the applied load. Under normal conditions, it provides sufficient constraint for stability; under elevated pressure from electrolyte expansion, it allows controlled deformation to accommodate volume changes.
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 design effectively suppresses electrolyte leakage and breakage, improving the reliability of the electricity-storage module by preventing deformation and extending the sealing route for the electrolyte, thus enhancing the module's overall performance.
Implementation Method 1
a sealing body that is provided to the stacked body so as to surround a peripheral edge portion of the electrodes, forms an inner space that stores an electrolytic solution between the electrodes adjacent to each other along the first direction, and seals the inner space
Implementation Method 2
a reinforcing body that is provided in the electrodes so as to suppress deformation of the electrodes
Implementation Method 3
a plurality of first sealing portions welded to the first surface at a peripheral edge portion of the electrodes
Data Source
AI summary
Provided is an electricity-storage module including: a stacked body that includes electrodes which are stacked along a first direction; a sealing body that is provided to the stacked body so as to surround a peripheral edge portion of the electrodes, forms an inner space that stores an electrolytic solution between the electrodes adjacent to each other along the first direction, and seals the inner space; and a reinforcing body that is provided in the electrodes so as to suppress deformation of the electrodes. The electrodes include bipolar electrodes and a negative terminal electrode, the negative terminal electrode includes the electrode plate and a negative electrode provided on the second surface, and is disposed at one end of the stacked body in the first direction such that the second surface faces an inner side of the stacked body in the first direction.