Battery Lug Redundant Section for Tensile Stress Buffering

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Solution Overview

Problem

Secondary battery lugs experience tearing or breaking due to excessive tensile stress caused by vibration and expansion of the electrode assembly, leading to potential structural failure and electrolyte leakage.

Innovation Solution

The secondary battery design incorporates a lug with a redundant section that buffers movement and deformation, reducing tensile stress by allowing relative movement between the lug and the current collecting member, thereby preventing tearing or breaking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lug is rigidly connected to the current collecting member, then the electrical connection is stable, but the lug is prone to tearing or breaking due to tensile stress from electrode assembly vibration and expansion

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidlug structural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The lug is divided into multiple sections: a fixed section rigidly connected to the current collecting member for stable electrical connection, and a redundant section with folded layers that can deform to absorb stress. This segmentation allows different parts of the lug to serve different functions - electrical stability and stress buffering respectively.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The redundant section of the lug is designed with folded layers before assembly, creating a built-in buffer structure that can absorb tensile stress from electrode assembly vibration and expansion. This pre-configured cushioning structure prevents stress concentration that would otherwise cause lug tearing or breaking.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If the lug structure is simplified without redundant section, then the manufacturing is easier, but the lug becomes vulnerable to tearing or breaking under tensile stress

Engineering Contradiction:
Improvelug manufacturing simplicityVSAvoidlug resistance to tearing or breaking
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The lug manufacturing process is segmented into forming the redundant section with folded layers and the connecting section. This segmentation allows the complex stress-buffering function to be achieved through a standardized folding process that can be integrated into existing manufacturing workflows without requiring completely new equipment or processes.

Inventive Principle:
Principle #1Segmentation

3Strength

If the lug has a redundant section with folded layers, then the tensile stress is reduced and lug failure is prevented, but the device complexity increases

Engineering Contradiction:
Improvelug resistance to tensile stressVSAvoidlug structural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The redundant section of the lug utilizes the flexibility of the conductive material itself, folding it into layered structures that can deform under stress. This approach uses the material's inherent flexibility rather than requiring separate flexible components, thereby reducing overall device complexity while maintaining stress resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3923373B1Secondary battery and battery module
Publication Date: 2025.11.12 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
  • EP3923373B1 patent drawingFigure 1
  • EP3923373B1 patent drawingFigure 2
  • EP3923373B1 patent drawingFigure 3

AI summary

The present application relates to a secondary battery and a battery module. The secondary battery includes: a casing including a receiving cavity having an opening; a top cover assembly, which the top cover assembly is connected to the casing to seal the opening, and an electrode assembly, disposed in the receiving cavity, in which the electrode assembly includes two end faces disposed opposite to each other in a first direction perpendicular to a depth direction of the receiving cavity, a lug extending from each end face; the lug is a layered structure and has a redundant section close to the end face and a connecting section connected to the redundant section; the current collecting member includes a current collecting portion fixedly connected to the connecting section. The lug of the secondary battery of the embodiment of the present application has the redundant section, which can effectively buffer the movement and reduce the possibility that the lug is torn or broken due to an excessive tensile stress.