Cylindrical Battery Center Pin Structure for Short-Circuit Prevention
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Solution Overview
Problem
Cylindrical secondary batteries face challenges with short circuits, bending imbalances, and defects due to the pressing of electrode tabs, as well as deformation of the winding core, which complicates the structure and increases process time in battery modules.
Innovation Solution
A cylindrical secondary battery design featuring a center pin with insulating flange parts that guides the electrode assembly during winding, preventing short circuits and deformation, while improving electrical insulation and bending balance by directly winding the electrode assembly around the center pin and using flange parts to support the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gasket is used to insulate the can and cap, then electrical insulation is improved, but the structure becomes more complex and bus bar connections require more components
Solution Approach 1:
The insulating gasket is integrated with the terminal structure to form a unified component. The terminal includes an insulating portion that combines the functions of electrical insulation and structural support, eliminating the need for separate gasket components and simplifying the overall battery structure.
Solution Approach 2:
The terminal structure is designed to perform multiple functions: it provides electrical connection through the conductive portion, electrical insulation through the insulating portion, and structural support for the electrode tabs. This multi-functional design reduces the number of separate components needed in the battery assembly.
2Manufacturing precision
If the electrode assembly is tightly wound to improve height consistency, then height dispersion is reduced, but the winding core may deform and cause short circuits
Solution Approach 1:
An insulating buffer structure is placed between the electrode assembly and the winding core before the winding process. This buffer prevents direct contact and potential short circuits while allowing the electrode assembly to be tightly wound for height consistency. The buffer acts as a protective barrier that cushions against deformation.
Solution Approach 2:
The insulating buffer serves as an intermediary element between the electrode assembly and the winding core. It mediates the interaction by providing mechanical support during winding while maintaining electrical insulation, thus enabling tight winding without causing short circuits or core deformation.
3Reliability
If bus bars are connected to upper and lower portions of batteries to improve electrical connection, then electrical conductivity is improved, but the process time and structural complexity increase
Solution Approach 1:
The terminal structure merges the functions of electrical connection and mechanical support into a single integrated component. The terminal is directly coupled to the electrode assembly and provides both electrical connectivity and structural stability, eliminating the need for separate bus bar connections and reducing assembly process time.
Data Source
AI summary
A cylindrical secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a center pin extending along a winding axis of the electrode assembly, the center pin including an insulating material and having a flange on at least one of an upper end and a lower end thereof; a case accommodating the electrode assembly and the center pin; a terminal extending through an upper end of the case and electrically connected to the first electrode plate of the electrode assembly; and a cap plate sealing a lower end of the case.