Battery Pack Lead Plate Turnback Structure for Impact Resistance

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Solution Overview

Problem

The existing battery pack design experiences internal stress during the bending process of the lead plate, which can cause the slender connective arm to break due to the reaction force, leading to potential failure under impact.

Innovation Solution

The battery pack design incorporates a lead plate with a turnback part that includes a through hole, side notch, and thinned part, allowing for a specified bending location that reduces the reaction force, thereby preventing the connective arm from breaking. The connective arm is connected to the flat parts of the lead plate without using a connective arm between the turnback part and the fixed pieces, and is designed to function as a fuse link with increased electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the lead plate is bent to turn back the turnback part at 180 degrees, then the battery pack structure is formed, but internal stress causes the slender connective arm to break on impact

Engineering Contradiction:
Improveturnback part shapeVSAvoidimpact strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent applies local quality by creating a bending part with different properties than the rest of the lead plate. The bending part has reduced thickness or modified material properties at specific locations (through holes, side notches, or thinned parts) to concentrate bending stress in a controlled region, preventing stress distribution that would cause connective arm breakage while maintaining the required 180-degree turnback shape

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the lead plate includes a slender connective arm for fuse link or current sensing, then functional versatility is improved, but the connective arm breaks under impact due to internal stress from bending

Engineering Contradiction:
Improvefunctional versatilityVSAvoidreliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent protects the slender connective arm by concentrating bending stress in the bending part through geometric modifications (through holes, notches, or thinned regions). This local modification ensures that the connective arm maintains its functional versatility for fuse link or current sensing applications while preventing stress-induced breakage, thereby improving reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bending part with reduced thickness or modified properties acts as a stress-absorbing element that preemptively handles bending stresses before they can propagate to the connective arm. This beforehand cushioning protects the vulnerable connective arm from impact forces while maintaining its functional integrity

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

Data Source

PatentEP3678211B1Battery pack and method for manufacturing same
Publication Date: 2023.09.27 PANASONIC ENERGY CO LTD
  • EP3678211B1 patent drawingFigure 1
  • EP3678211B1 patent drawingFigure 2
  • EP3678211B1 patent drawingFigure 3

AI summary

Provided are a battery pack that has such superior impact strength as to prevent a slender connective arm from breaking on impact, and a method for manufacturing this battery pack. The battery pack includes a plurality of batteries (1) each including respective electrode terminals (1x, 1y) disposed in face-to-face relation, and lead plate (3) connecting each of the plurality of batteries (1). Lead plate (3) includes turnback part (33) and fixed piece (31) connected to electrode terminal (1x, 1y). Lead plate (3) also includes flat part (32) at each of ends of turnback part (33), and connective arm (34) that has a narrower width than fixed piece (31) and connects flat part (32) and fixed piece (31). Turnback part (33) includes bending part (37). Bending part (37) includes any one of through hole (37A) provided in turnback part (33), side notch (37B) where turnback part (33) has a narrower width, and thinned part (37C) that is a thinned part of turnback part (33).