Cylindrical Battery Fixing Plate Layout to Avoid Weld Mark Shorts

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Solution Overview

Problem

Conventional battery packs with metal fixing plates on cylindrical batteries face a higher risk of short-circuiting due to weld marks at the connection points, compromising safety.

Innovation Solution

A battery pack design featuring a cylindrical battery with a metal fixing plate spaced apart from weld marks by a minimum distance of 1.5 mm-30 mm, equipped with insulating layers to prevent electrical connections, providing structural support and thermal conductivity while reducing the risk of short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal fixing plate is disposed on the third surface of the cylindrical battery, then structural support and thermal conductivity are improved, but the risk of short-circuiting increases due to proximity to weld marks

Engineering Contradiction:
Improvestructural supportVSAvoidshort-circuit risk
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

An insulating layer is introduced as an intermediary between the metal fixing plate and the weld mark region. This insulating layer prevents direct electrical contact while allowing the fixing plate to maintain its structural and thermal functions, thus resolving the contradiction between strength improvement and short-circuit risk reduction

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The problem is solved by transitioning from a two-dimensional surface placement issue to a three-dimensional spatial arrangement. By specifying minimum spacing distances (1.5mm-30mm) in the axial direction and radial direction, the fixing plate is positioned in a safe zone that maintains functional performance while avoiding electrical contact hazards

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the fixing plate is placed close to the weld mark region, then structural support is maximized, but electrical insulation becomes difficult to ensure

Engineering Contradiction:
Improvestructural supportVSAvoidelectrical insulation
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The insulating layer serves as a mediator that enables close positioning of the fixing plate to the weld mark region without compromising electrical insulation. The insulating layer can be applied as a coating or embedded structure that maintains both mechanical support and electrical isolation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The minimum spacing parameters are optimized to balance structural support requirements with electrical insulation needs. By establishing specific distance thresholds (1.5mm-30mm in axial direction, 0.5mm-5mm in radial direction), the design achieves optimal positioning that satisfies both structural strength and electrical safety requirements

Inventive Principle:
Principle #35Parameter changes

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 design effectively avoids short circuits and enhances safety by maintaining a safe distance from weld marks, ensuring strong structural support and thermal conductivity performance.

Implementation Method 1

the third surface is provided with a first insulating layer; the first insulating layer does not cover the first weld mark; effectively avoid the electric connection between the fixing plate and the relevant region of the cylindrical battery

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

the fixing plate is made of a metal material, wherein the fixing plate is disposed opposite and fixedly connected to the third surface; provide strong structural support and thermal conductivity performance

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Data Source

PatentEP4641791A1Battery pack
Publication Date: 2025.10.29 CALB GROUP CO LTD
  • EP4641791A1 patent drawingFigure 1
  • EP4641791A1 patent drawingFigure 2~3
  • EP4641791A1 patent drawingFigure 4

AI summary

A battery pack includes a battery box (100), a cylindrical battery (200) and a fixing plate (300). A first surface (210) and a second surface (220) of the cylindrical battery (200) are arranged in and respectively perpendicular to a first direction (X). A third surface (230) is connected between the first surface (210) and the second surface (220). A first weld mark (231) is formed at a connection region of the third surface (230) and the first surface (210). The third surface (230) is provided with a first insulating layer (240) which does not cover the first weld mark (231). The fixing plate (300) is disposed opposite and fixedly connected to the third surface (230). The first weld mark (231) is spaced apart from the fixing plate (300). A minimum spacing between the first surface (210) and the fixing plate (300) in the first direction (X) is 1.5 mm-30 mm.