Battery Pack Case Cover Welding for Protection Plate Space

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Solution Overview

Problem

Conventional battery pack designs face issues with insufficient snap-fit forces in buckles, leading to increased space occupation and higher design and processing costs, while complex buckles require larger battery pack cases and complicate assembly.

Innovation Solution

A battery pack design featuring a frame body with partition strips and protrusions for the cover plate, allowing laser welding without additional buckles, ensuring sufficient space for protection plates and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional battery pack case structure is used, then the manufacturing process is simple, but the case cannot effectively prevent deformation during welding and has poor sealing performance

Engineering Contradiction:
Improvesealing performanceVSAvoidcase structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The battery pack case is divided into a first case component and a second case component, with the first case component further segmented into a first side wall component and a second side wall component. This segmentation allows each component to be independently formed with optimized geometry, enabling effective deformation prevention during welding while achieving reliable sealing performance through precise mating surfaces and sealing structures.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the case structure is optimized to prevent deformation, then welding quality improves, but the manufacturing complexity increases

Engineering Contradiction:
Improvewelding qualityVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The case components are pre-formed with specific geometric features including reinforcing ribs and optimized wall thickness distributions before welding. The first and second side wall components are preliminarily shaped with deformation prevention structures that maintain dimensional stability during subsequent welding operations, thereby improving welding quality without requiring complex real-time control during manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the case has high structural strength to prevent deformation, then welding quality is maintained, but heat dissipation performance deteriorates

Engineering Contradiction:
Improvewelding qualityVSAvoidheat dissipation performance
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The case structure implements local quality optimization by providing reinforcing ribs and increased wall thickness only in specific regions where deformation prevention is critical during welding, while maintaining thinner walls and better thermal conductivity in regions where heat dissipation is prioritized. This localized structural differentiation maintains welding quality while preserving heat dissipation performance.

Inventive Principle:
Principle #3Local quality

4Reliability

If conventional sealing structures are used, then the manufacturing process is simple, but sealing performance is insufficient leading to electrolyte leakage

Engineering Contradiction:
Improvesealing performanceVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing function is merged into the case structure itself through integrated sealing ribs and mating surfaces formed directly on the first and second case components. The sealing structures are combined with the structural components rather than being separate elements, achieving reliable sealing performance while minimizing additional manufacturing steps and overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4507095B1Battery pack case and battery pack
Publication Date: 2026.05.06 ZHUHAI COSMX POWER CO LTD
  • EP4507095B1 patent drawingFigure 1
  • EP4507095B1 patent drawingFigure 2
  • EP4507095B1 patent drawingFigure 3

AI summary

Disclosed are a battery pack case and a battery pack. The battery pack case includes a frame body and a cover plate. The frame body includes partition strips, and the frame body is internally provided with an accommodating position for a protection plate defined by the partition strips. The cover plate is assembled on an upper opening of the accommodating position for the protection plate. A top end of the partition strips is provided with first protrusions and second protrusions, and the second protrusions are located at an outer side of the first protrusions and are higher than the first protrusions. An edge of the cover plate is limited to inner sides of the second protrusions and is supported on the first protrusions. A lower end of the edge of the cover plate is fixedly connected to the upper ends of the first protrusions in a manner of laser welding. According to the present disclosure, by means of welding, a space occupied by an additionally providing buckle may be saved, thereby ensuring that the accommodating position for the protection plate has a size required to accommodate a protection plate. In addition, arrangement of the second protrusions may play a limiting function on the cover plate supported on the first protrusions.