Electrode Body Holder Layout for Battery Expansion Control
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Solution Overview
Problem
The expansion of electricity storage devices, particularly at their end of life, leads to increased internal resistance and decreased capacity due to reduced contact area between electrode bodies and electrolytic solution, potentially damaging the connection between the outer can and sealing plate, thereby compromising the reliability of the device and module.
Innovation Solution
Incorporating an electrode body holder with an insulating property, fixed to the sealing plate, to suppress the displacement of electrode bodies within the outer can, combined with a configuration that reserves space for expansion, thereby maintaining a stable electrical connection and reducing stress on collector tabs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity of electricity storage device is increased, then the energy storage capability is improved, but the expansion amount increases leading to reduced reliability
Solution Approach 1:
The invention introduces a partition wall that divides the inner space of the outer can into multiple regions, effectively segmenting the expansion space. This allows the electrode body to expand within designated regions without causing excessive overall expansion or damaging connections to the sealing plate, thus maintaining reliability while supporting higher capacity
Solution Approach 2:
The partition wall extends in a direction intersecting the direction from the electrode body toward the sealing plate, creating a three-dimensional expansion management structure. This dimensional approach allows expansion to be contained laterally rather than uniformly in all directions, preventing contact area reduction and maintaining electrical connection stability
2Volume of moving object
If the inner volume of electricity storage device increases due to expansion, then the electrode body has more space, but the water level of electrolytic solution is lowered decreasing contact area
Solution Approach 1:
The partition wall segments the inner volume into functional regions, allowing the electrode body to occupy and expand within its designated region while the electrolytic solution level is maintained in other regions. This segmentation ensures that expansion does not uniformly reduce the contact area between the electrode body and electrolytic solution
3Quantity of substance
If the expansion amount excessively increases, then the electrode body can accommodate more material, but the connection between outer can and sealing plate may be damaged
Solution Approach 1:
By dividing the inner space with a partition wall, the invention localizes expansion forces to specific regions away from the sealing plate connection. This prevents excessive cumulative expansion from damaging the outer can to sealing plate connection, maintaining structural strength while accommodating increased electrode material
Solution Approach 2:
The partition wall acts as an intermediary structure that manages and directs expansion forces. It provides a physical barrier that prevents direct transmission of expansion stress to the sealing plate connection, protecting the joint while allowing the electrode body to expand with increased material content
Data Source
AI summary
Electricity storage device includes: outer can having opening; electrode body housed in outer can; sealing plate that closes opening; a pair of output terminals arranged on sealing plate; current collector by which electrode body are electrically connected to the pair of output terminals and electrode body holder that is housed in outer can, includes flat plate extending in a direction intersecting a direction in which each of electrode body and sealing plate are arranged, and is fixed to sealing plate to suppress displacement of electrode body, electrode body holder having an insulating property.