Battery Pack Casing Structure for Side-Collision Load Distribution

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Solution Overview

Problem

Battery packs in vehicles are prone to deformation and leakage during side collisions due to the transfer of forces from the tray's long side beams to the central battery cores, posing a safety hazard of fire and explosion.

Innovation Solution

A battery pack casing design that includes a tray with a middle beam and a cover plate, fastened to a vehicle's transverse beam using mounting members, enhancing the structural integrity and impact resistance by distributing forces away from the battery units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the battery pack is fixed using only the tray's side beams, then the structure is simple, but the ability to withstand side collisions is insufficient causing battery deformation and leakage

Engineering Contradiction:
Improveability to withstand side collisionsVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The tray structure is segmented by adding a middle beam that divides the central area into two regions, creating additional structural support zones. This segmentation strengthens the overall structure against side collisions while maintaining modular assembly through the separate middle beam component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The middle beam extends in the longitudinal direction (another dimension relative to the transverse side beams), creating a three-dimensional structural framework. This dimensional addition provides force distribution paths that were previously unavailable in the two-dimensional tray structure

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

2Object-affected harmful factors

If the long side beam is allowed to deform under collision force, then the structure is flexible, but the battery cores undergo deformation and leakage causing fire and explosion hazards

Engineering Contradiction:
Improvebattery deformation and leakage riskVSAvoidside beam strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The middle beam acts as an intermediary structural element between the side beams and the central battery cores. It intercepts and redistributes collision forces before they can reach the battery cores, preventing direct force transmission that would cause deformation and leakage

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The middle beam is positioned in advance to provide structural cushioning and force distribution before collisions occur. Its presence creates a pre-established force transfer path that protects the battery cores from direct impact forces

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

Data Source

PatentEP3916897B1Battery pack casing, battery pack and vehicle
Publication Date: 2025.09.17 BYD CO LTD
  • EP3916897B1 patent drawingFigure 1
  • EP3916897B1 patent drawingFigure 2
  • EP3916897B1 patent drawingFigure 3

AI summary

A battery pack casing, a battery pack using the battery pack casing, and a vehicle with the battery pack are provided. The battery pack casing comprises a tray, a middle beam, a cover plate and a mounting member. The tray comprises a bottom plate and a plurality of side beams, which together form a receiving space for accommodating a battery unit, wherein the receiving space is open at one side, and the cover plate is configured to close the open side of the receiving space. The plurality of side beams comprise two first side beams arranged opposite to each other. The middle beam is located in the receiving space and two ends of the middle beam along a length direction are respectively spaced by a predetermined distance from or in contact with the two first side beams. The length of the middle beam is greater than a projection dimension of the battery unit along the length direction of the middle beam. The mounting member is configured to sequentially extend through and fasten the bottom plate, the middle beam and the cover plate, and also configured to be connected and fixed to the transverse beam of the vehicle body. The battery pack casing aims to improve the ability of the battery pack casing to withstand collisions from the side, which is beneficial to the decrease in the design strength of a transverse beam of a vehicle body.