Battery Module End Plate Layout Against Cell Expansion Breakage

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Solution Overview

Problem

The existing battery modules face a challenge with the low strength of the end plate under the expansion force of the battery, which can lead to breakage and reduced assembly reliability.

Innovation Solution

The proposed battery module features an end plate with a specific design, including an inner wall and an external wall with end plate mounting holes positioned asymmetrically, providing greater thickness at the mounting holes to enhance strength and reduce deformation under battery expansion forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the end plate is provided with mounting holes for assembling battery modules, then the battery module can be assembled into battery packs, but the inner end surface of the end plate has low strength and risks breaking under expansion force

Engineering Contradiction:
Improveassembly capabilityVSAvoidend plate strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies asymmetry by positioning the mounting holes closer to the outer end surface than the inner end surface of the end plate. This asymmetric arrangement ensures that the remaining plate thickness is greater near the inner end surface, which is the location experiencing maximum expansion force from the battery. This resolves the contradiction by maintaining assembly capability through mounting holes while preventing breakage through asymmetric hole placement that preserves structural strength at the critical inner surface.

Inventive Principle:
Principle #4Asymmetry

2Strength

If the end plate thickness is increased to prevent breakage, then the strength increases, but the mounting hole positioning becomes more constrained

Engineering Contradiction:
Improveend plate strengthVSAvoidmounting hole positioning complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The asymmetric positioning of mounting holes provides a clear design guideline that simplifies the positioning process. By specifying that holes should be closer to the outer surface, the patent creates an intuitive and straightforward mounting hole arrangement that does not increase device complexity. Instead, it offers a simple rule-based solution that is easy to implement during manufacturing while ensuring adequate strength.

Inventive Principle:
Principle #4Asymmetry

3Duration of action of moving object

If the end plate is subjected to maximum expansion force at the inner end surface, then the battery can expand during operation, but the inner end surface has a high risk of breaking

Engineering Contradiction:
Improvebattery operationVSAvoidend plate reliability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The asymmetric mounting hole positioning directly addresses the reliability issue by ensuring greater plate thickness at the inner end surface where maximum expansion force occurs during battery operation. This allows the battery to expand and contract during its operational lifetime while the reinforced inner surface prevents breaking, thereby maintaining both operational duration and reliability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by creating a region of greater thickness specifically at the inner end surface near the mounting holes. This localized structural reinforcement is precisely where the expansion force is maximum, allowing the end plate to maintain adequate strength at the critical location while preserving the overall functionality of the battery module.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3703153B1Battery module
Publication Date: 2025.05.14 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
  • EP3703153B1 patent drawingFigure 1
  • EP3703153B1 patent drawingFigure 2~3

AI summary

The present disclosure provides a battery module, comprising: a plurality of batteries stacked in a length direction L of the battery module; and an end plate located at an end of the plurality of batteries in the length direction L. The end plate is provided with at least one end plate mounting hole, and each of the at least one end plate mounting hole extends along a height direction H of the battery module. The end plate includes an inner wall and an external wall that are disposed opposite to each other in the length direction L, and an axis of each of the at least one end plate mounting hole includes a first distance L1 from the inner wall and a second distance L2 from the external wall. The first distance L1 is greater than the second distance L2. If the end plate has a greater thickness at the position of the first end plate mounting hole, a risk of the inner wall breaking under the expansion force of the battery can be reduced, so that the strength of the end plate can be increased. Moreover, the structure of the end plate in this embodiment can also reduce a risk that the external wall deforms outwards under an expansion force of the battery, thereby reducing pressing of the mounting bolt caused by the deformation of the inner wall and thus improving the assembly reliability and stability of the battery module.