Rechargeable Battery Case With Curved Joints For Controlled Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable batteries face the risk of internal short circuits and potential fires or explosions when compressed, as the case bending is difficult to control, leading to unpredictable deformation and contact between electrodes.
Innovation Solution
The battery case is designed with distinct areas of varying curvature and thickness, featuring internal curved surfaces and joint portions that differentiate in mechanical strength to induce controlled bending and prevent short circuits under compression, with the second area having a greater curvature radius and thickness than the first area, allowing for controlled deformation and reduced risk of internal short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the case is made with uniform thickness and curvature, then the manufacturing process is simple, but the bending direction cannot be controlled under compression leading to short circuits
Solution Approach 1:
The case is designed with non-uniform thickness distribution, where the first portion (center region) has smaller thickness and the second portion (side regions) has greater thickness. This local variation in thickness creates different mechanical properties in different regions, enabling controlled bending toward the thinner first portion when compressed, thereby preventing short circuits while maintaining manufacturing feasibility.
Solution Approach 2:
The case incorporates curved surfaces with different radii of curvature in different portions. The first portion has a smaller radius of curvature while the second portion has a greater radius of curvature. This curvature variation creates stress concentration in the first portion during compression, guiding the bending direction predictably toward the center region and preventing electrode contact.
2Strength
If the case thickness is increased throughout to prevent deformation, then structural strength is improved, but the ability to induce controlled bending is reduced
Solution Approach 1:
Rather than uniformly increasing thickness, the invention applies thickness variation locally: the second portion (side regions) has greater thickness to provide structural strength and resistance to compression, while the first portion (center region) has smaller thickness to serve as the intended bending zone. This local differentiation allows the case to maintain overall strength while enabling controlled deformation in specific regions.
3Reliability
If the case is designed with varying thickness and curvature, then controlled bending is achieved preventing short circuits, but manufacturing complexity increases
Solution Approach 1:
The invention uses continuous curved surfaces with varying radii of curvature to achieve the thickness variation, rather than employing discrete geometric shapes or multiple assembled components. This approach to varying curvature can be implemented through conventional forming processes, reducing manufacturing complexity compared to alternative designs that might require complex assemblies or precision-machined features.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a rechargeable battery for preventing a short circuit of a cell by inducing bending of a case under compression. The rechargeable battery comprises a case comprising a bottom portion and front and rear portions connected to the bottom portion by joint portions including internal curved surfaces, an electrode assembly in the case and a cap assembly closing the case, wherein the curved surfaces define a first portion A1 in a centre portion of the case and second portions A2 on either side of the first portion, wherein the second portions have a higher mechanical strength than the first portion with respect to a compression force applied to the sides of the case.