Battery Pack Partition Wall Bolting Against Module Swelling

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Solution Overview

Problem

Existing battery packs face issues with deformation and damage due to swelling phenomena in battery modules, and conventional welding methods are inconvenient and require frequent equipment changes.

Innovation Solution

A battery pack design that fixes an auxiliary partition wall using a long bolt member inserted into the pack case, minimizing welding and enhancing the side support strength of battery modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding method is used to fix the auxiliary partition wall to the base plate, then the auxiliary partition wall can be firmly fixed, but the base plate or auxiliary partition wall may be bent or distorted due to welding heat and it is inconvenient to change welding equipment every time the shape of the pack case is changed

Engineering Contradiction:
Improvefixing strength of auxiliary partition wallVSAvoidmanufacturing convenience and equipment flexibility
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the welding process with a mechanical fastening system using bolts. The auxiliary partition wall is fixed to the base plate through bolt connections rather than thermal welding, eliminating heat-induced deformation while maintaining firm fixation. This mechanical substitution allows for easier assembly, disassembly, and adaptation to different pack case shapes without requiring specialized welding equipment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If the auxiliary partition wall is not installed for preventing swelling, then the structure is simpler, but the auxiliary partition wall cannot withstand the expansion force of the battery module when swelling occurs

Engineering Contradiction:
Improvestructural simplicityVSAvoidresistance to expansion force
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent divides the partitioning function into multiple components: the auxiliary partition wall for separating battery modules and the bolt fixation system for providing mechanical support against swelling. This segmentation allows the auxiliary partition wall to perform its primary separation function while the bolted connection to the base plate provides the necessary structural reinforcement to withstand expansion forces, achieving both simplicity and strength.

Inventive Principle:
Principle #1Segmentation

3Strength

If a bolt is inserted to fix the auxiliary partition wall, then the side support force of the battery module is improved, but the device complexity increases

Engineering Contradiction:
Improveside support force of battery moduleVSAvoidnumber of fastening components
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent designs the bolt fixation system to serve multiple functions simultaneously: the bolts not only fix the auxiliary partition wall to the base plate but also provide lateral support to the battery modules, preventing swelling and maintaining structural integrity. This multi-functionality reduces the need for additional separate support components, thereby limiting the increase in device complexity while achieving improved side support force.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4439837B1Battery pack
Publication Date: 2026.02.18 LG ENERGY SOLUTION LTD
  • EP4439837B1 patent drawingFigure 1(a)~1(b)
  • EP4439837B1 patent drawingFigure 2
  • EP4439837B1 patent drawingFigure 3

AI summary

The present invention relates to a battery pack, and the battery pack of the present invention is a battery pack configured to accommodate a battery module including a cell stack in which a plurality of cells are stacked, and includes a pack case including a base plate configured to support a lower portion of the battery module, a main partition wall coupled to a center portion of the base plate and formed to extend across the base plate, a side wall coupled along an edge of the base plate, and an auxiliary partition wall having both ends coupled to the main partition wall and the side wall, respectively, and a long bolt member coupled to the pack case by passing through the auxiliary partition wall such that the auxiliary partition wall is coupled to the main partition wall and the side wall.