Stretchable Electrode Lead Inside Battery Case Prevents Tab Disconnection
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Solution Overview
Problem
Conventional secondary batteries face disconnection issues of the electrode tab due to excessive tension generated during the expansion of the electrode assembly, particularly in stacked-type batteries where the electrode lead is not flexible and is fixed between sealed battery cases.
Innovation Solution
Incorporating a flexible part on the electrode lead with stretchability parallel to its protruding direction, made of materials like gold or silver, which is located inside the battery case to absorb expansion, reducing tension on the electrode tab and preventing disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode lead is fixed and not flexible in conventional secondary batteries, then the battery structure is simple and manufacturing is easy, but excessive tension is generated on the electrode tab during electrode assembly expansion causing disconnection
Solution Approach 1:
The electrode lead is designed with a flexible portion that can dynamically change its shape and length in response to electrode assembly expansion. The flexible portion includes a bent section that allows the lead to stretch and absorb expansion forces, transforming the rigid fixed structure into a dynamic adaptive structure that maintains reliable electrode tab connection during battery operation.
Solution Approach 2:
The electrode lead incorporates a flexible portion made of flexible material that can bend and stretch. This flexible section acts as a buffer zone that absorbs the mechanical stress generated during electrode assembly expansion, preventing the stress from being transmitted to the electrode tab connection point and thus maintaining connection reliability.
2Reliability
If a flexible portion is added to the electrode lead to absorb expansion, then tension on the electrode tab is reduced preventing disconnection, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The electrode lead is segmented into a rigid portion and a flexible portion with distinct functions. The rigid portion provides structural support and electrical connection, while the flexible portion with bent sections absorbs expansion forces. This segmentation allows each part to be optimized independently, making the overall manufacturing process more manageable despite the increased complexity.
Solution Approach 2:
The flexibility of the electrode lead is achieved by changing the geometric parameters of the lead structure, specifically by creating bent sections with controlled radii and angles. By adjusting these geometric parameters, the flexibility characteristics can be tuned to match the expected expansion of the electrode assembly, allowing manufacturers to optimize the design for specific battery applications without completely redesigning the lead structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The flexible part effectively reduces tension on the electrode tab during electrode assembly expansion, preventing disconnection and enhancing the reliability of the battery by allowing the electrode lead to stretch in the direction of expansion.
Implementation Method 1
the electrode lead includes a flexible part having stretchability in a direction parallel to the protruding direction of the electrode lead
Data Source
AI summary
A secondary battery includes an electrode assembly including electrode sheets on which electrode tabs are formed and a separator located between the electrode sheets; a battery case in which the electrode assembly is housed; and an electrode lead connected to the electrode tab and protruding to the outside of the battery case, wherein the electrode lead includes a flexible part having stretchability in a direction parallel to the protruding direction of the electrode lead, and wherein the flexible part is located inside the battery case.