Battery Frame Joint Structure for Collision Load Transfer

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Solution Overview

Problem

Existing battery units fail to adequately protect battery cells from both frontal and side collisions by improperly transmitting collision loads to longitudinal and lateral frames.

Innovation Solution

A battery unit design featuring a square frame configuration with step-shaped connection portions between longitudinal and lateral frames, allowing for efficient transmission of collision loads to ensure proper protection of battery cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the end portion of the longitudinal frame and the end portion of the lateral frame merely abut each other with corner brackets, then the device complexity is reduced, but the collision load transmission capability deteriorates

Engineering Contradiction:
Improveframe connection structureVSAvoidcollision load transmission
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The connection structure transitions from a simple abutment in one dimension to a multi-dimensional integrated structure where the lateral frame's connection portion embeds into the longitudinal frame's hollow cross-section, creating spatial interlocking in multiple dimensions for superior load transmission

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

Solution Approach 2:

The connection portion of the lateral frame is inserted into the hollow cross-section of the longitudinal frame, creating a nested configuration where one structural element is placed within another to achieve strong mechanical coupling and effective collision load transmission

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If corner brackets are used to connect longitudinal and lateral frames, then the ease of manufacture is improved, but the reliability of battery cell protection deteriorates

Engineering Contradiction:
Improveframe assemblyVSAvoidbattery cell protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The corner bracket connection is replaced by a direct integrated connection where the lateral frame's connection portion merges with the longitudinal frame's hollow cross-section, eliminating the need for separate corner brackets and achieving both manufacturing efficiency and superior protection reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hollow cross-section of the longitudinal frame serves as an intermediary structure that receives and transmits collision loads from the lateral frame to the battery case, effectively mediating the load path to protect battery cells

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4640462A1Battery unit
Publication Date: 2025.10.29 MAZDA MOTOR CORP
  • EP4640462A1 patent drawingFigure 1
  • EP4640462A1 patent drawingFigure 2
  • EP4640462A1 patent drawingFigure 3

AI summary

A battery case has a pair of first frames extending in a first direction, one of longitudinal-and-lateral directions, and a pair of second frames extending in a second direction, the other of the longitudinal-and-lateral directions, and is configured in a square frame shape such that the first and second frames enclose battery cells. The first frame includes a first contact face arranged to face the second frame and a first connection portion to connect to the second frame. The second frame includes a second contact face arranged to face the first frame and a second connection portion to connect to the first frame. The first frame has a step-shaped first step portion which forms a first space where at least part of the second connection portion of the second frame is stored in least part of the first contact face is provided at the first step portion.