Cylinder Lithium Ion Battery Center Pin Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cylinder type lithium ion secondary batteries face internal electrical shorts during compression and collision, and inefficient gas release due to internal combustion, which compromises safety and performance.
Innovation Solution
A center pin with a hollow inner space and tapered outer diameters, uniform wall thickness, and throughholes or slits is designed to prevent deformation and facilitate gas release, ensuring the battery's structural integrity and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the center pin has a uniform outer diameter throughout, then the manufacturing process is simple, but the battery experiences internal electrical shorts during compression and collision
Solution Approach 1:
The center pin is designed with varying outer diameters at different locations (upper portion, lower portion, and central portion have different diameters). This local variation in geometry provides enhanced structural support at critical areas where compression and collision forces are applied, preventing internal electrical shorts without requiring complex reinforcement throughout the entire pin structure.
2Strength
If the center pin wall thickness is increased throughout, then the structural strength is improved, but the gas release capability during internal combustion is reduced
Solution Approach 1:
The center pin incorporates throughholes penetrating its wall structure. These throughholes create a porous-like pathway system that allows gas generated during internal combustion to escape through the center pin walls. The presence of these holes maintains adequate wall thickness for structural strength while providing controlled gas release channels to prevent dangerous gas accumulation.
3Force
If the center pin outer diameter is increased at upper and lower portions, then the resistance to compression and collision is improved, but the manufacturing precision requirements are increased
Solution Approach 1:
The center pin features tapered portions where the outer diameter gradually changes from the upper and lower portions to the central portion. This curved, continuous transition geometry distributes stress more effectively during compression and collision, enhancing mechanical resistance. The tapered design also provides smooth stress flow paths that reduce concentration points, making the structure more robust while maintaining manufacturability through standard machining processes.
Data Source
AI summary
Provided is a cylinder type lithium ion secondary battery capable of preventing an internal electrical short due to compression of a center pin in compression and collision. The cylinder type lithium ion secondary battery includes a cylindrical can, an electrode assembly housed in the cylindrical can, a center pin inserted into the electrode assembly, and a cap assembly sealing the cylindrical can. The center pin has a hollow inner space and a wall surrounding the inner space. Outer diameters of an upper portion and lower portion of the center pin are larger than an outer diameter of a central portion of the center pin. Therefore, an internal electrical short due to compression of the center pin can be prevented in compression and collision.