Wound Electrode Slit Structure for Shorter Battery Terminal Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional secondary batteries face challenges in efficiently joining the electrode terminal to the non-formation portion of the wound electrode body, leading to longer terminal lengths and increased material costs due to the difficulty in forming a flat surface for connection.
Innovation Solution
The proposed secondary battery design incorporates a flat wound electrode body with a non-formation portion featuring a first slit at the end portion, allowing for easier flattening and providing a flat surface for reliable terminal connection, and optionally a second slit along the winding axis direction to facilitate terminal joining, thereby reducing terminal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode terminal is connected to the non-formation portion positioned in a central portion of the wound electrode body, then the connection is achieved, but the internal terminal portion becomes relatively long increasing material cost
Solution Approach 1:
The non-formation portion is pre-flattened to create a flat surface before the electrode terminal is connected. This preliminary flattening action enables the terminal to be connected at the end portion of the wound electrode body rather than the central portion, thereby shortening the internal terminal portion length while maintaining reliable connection
2Reliability
If a flat surface is formed in the non-formation portion for terminal connection, then the terminal joining is reliable, but the manufacturing process becomes more complex
Solution Approach 1:
The non-formation portion is pre-flattened during the electrode body manufacturing process to create a flat surface. This preliminary action ensures that when the electrode terminal is connected, there is already a flat surface available, eliminating the need for additional flattening steps and simplifying the overall manufacturing process
Solution Approach 2:
Only the non-formation portion at the end of the electrode sheet is flattened to create a local flat surface for terminal connection. The rest of the wound electrode body maintains its compact wound structure. This localized flattening approach ensures reliable terminal joining while minimizing impact on the overall manufacturing process
Data Source
AI summary
A secondary battery includes a flat wound electrode body in which an electrode sheet is wound, and an electrode terminal. The electrode sheet has a current collector, an electrode active material layer which is formed on a surface of the current collector, and a non-formation portion in which the electrode active material layer is not formed on the surface of the current collector. The wound electrode body has a first end portion in which a rounded portion is formed. A first slit is formed along a winding direction in the non-formation portion at the first end portion. A flat surface portion to which the electrode terminal is joined is provided in a portion positioned further toward opposite than the first slit from the electrode active material layer in a portion of the non-formation portion at the first end portion.