Secondary Battery Assembly with Non-Uniform Contact Pressure
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Solution Overview
Problem
Conventional secondary battery assemblies fail to maintain uniform surface pressure, particularly when subjected to high-rate charge and discharge cycles, leading to uneven internal pressure and accelerated deterioration.
Innovation Solution
A secondary battery assembly with a contact member that includes discrete contact parts and a connecting part, where the contact parts protrude to apply stronger pressure to the sides and less pressure to the center, ensuring uniform surface pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional binding methods are used to maintain the flat shape of the outer case, then the planarity of the side surface is maintained, but the surface pressure becomes non-uniform with higher pressure at the central portion and lower pressure at the side portions
Solution Approach 1:
The contact member incorporates contact parts with different protruding heights at different locations: taller contact parts at the side portions and shorter contact parts at the central portion. This local differentiation in geometry creates the desired local quality variation in pressure distribution, applying higher pressure where needed (sides) and lower pressure where not needed (center), thereby resolving the contradiction between maintaining planarity and achieving uniform pressure.
2Stability of the object's composition
If the secondary battery is bound to keep its flat shape during high-rate charge and discharge, then the outer case maintains its form, but the internal pressure becomes higher at the central portion leading to accelerated deterioration
Solution Approach 1:
The contact member uses contact parts with varying protruding heights to create localized pressure differences. The taller contact parts at the side portions apply higher pressure to counteract the internally generated pressure, while the shorter contact parts at the central portion apply less pressure. This local quality approach prevents the harmful concentration of pressure at the center, thereby improving battery reliability while maintaining the flat shape.
3Ease of manufacture
If uniform binding pressure is applied across the entire pressed surface, then the binding is simple and consistent, but it fails to compensate for the non-uniform internal pressure distribution in high-rate batteries
Solution Approach 1:
Rather than applying uniform pressure, the invention deliberately creates non-uniform pressure distribution through contact parts of different heights. This targeted approach, while slightly more complex in design, actually simplifies the overall system by eliminating the need for complex active control mechanisms to achieve pressure uniformity. The passive geometric design of the contact member provides the necessary pressure compensation, improving reliability without significantly complicating manufacturing.
Data Source
AI summary
A secondary battery assembly of the present invention comprises: a secondary battery including a wound electrode body enclosed in a flat rectangular case; a contact member partly contacting a side surface having a maximum area (pressed surface) of outer surfaces of the battery; and a binding member for binding the battery and the contact member, the binding member binding the contact member to partly press against the pressed surface. The contact member includes: a plurality of contact parts arranged discretely, each contact part being in contact with the pressed surface; and a connecting part connecting the contact parts. The contact parts are protruding from the connecting part toward the pressed surface, and to press more strongly both one-side regions of the pressed surface corresponding to portions off the center of the wound body in the winding axis direction, and to press less strongly a central region between the one-side regions.