Elastomer Battery Cell Separator Structure for Expansion Pressure Relief

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Solution Overview

Problem

Existing power supply devices with stacked battery cells face issues due to the rapid increase in surface pressure between battery cells and separators, leading to the need for strong materials and increased weight and size, as well as potential misalignment causing electrical failures.

Innovation Solution

The use of an elastomer separator with uneven layers on both surfaces, featuring different deformation amounts, to absorb the expansion of battery cells, thereby reducing stress on end plates and binding bars, and improving electrolyte solution fluidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plate-shaped insulating plastic plate is used as the separator, then the adjacently stacked battery cells are insulated, but the separator cannot absorb the expansion of the battery cells, causing rapid increase in surface pressure and requiring very strong end plates and binding bars

Engineering Contradiction:

Improveinsulation of battery cellsVSAvoidstrength of end plates and binding bars

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The separator material is changed from rigid plastic to elastomer, fundamentally altering its mechanical properties. This allows the separator to dynamically change its thickness and absorb expansion forces, preventing the need for excessively strong end plates and binding bars while maintaining insulation functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The separator is constructed as a composite structure combining an elastomer base layer with uneven layers on both surfaces. The elastomer provides expansion absorption capability, while the uneven layers maintain insulation performance and provide differential deformation characteristics to manage stress distribution

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If the battery cells are fixed in a strongly pressurized state, then positional displacement due to expansion is prevented, but the weight and size of the power supply device increase

Engineering Contradiction:

Improvepositional stability of battery cellsVSAvoidweight of power supply device

Core Design Contradiction:

Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The separator's transition from rigid to elastomeric material changes its mechanical behavior from resisting expansion to absorbing it. This allows the battery cells to be held in position through elastic deformation rather than rigid constraint, reducing the need for heavy pressing forces and associated structural components

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastomer separator acts as a pre-positioned cushioning element that anticipates and absorbs expansion forces before they can cause positional displacement or damage. This proactive absorption mechanism eliminates the need for overly strong mechanical constraint systems

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If the separator is made of elastomer with uneven layers, then the expansion of battery cells is absorbed and stress on end plates is reduced, but the structure becomes more complex

Engineering Contradiction:

Improvestress resistance of end plates and binding barsVSAvoidstructure of separator

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The uneven layers are applied locally on the surfaces of the elastomer separator rather than throughout the entire structure. This localized complexity provides the necessary differential deformation capability and stress distribution while keeping the bulk of the separator simple and manufacturable

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator is segmented into distinct functional layers: the elastomer base layer for expansion absorption and the uneven surface layers for stress management and insulation. This segmentation allows each layer to perform its specific function optimally while maintaining overall structural coherence

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The elastomer separator effectively absorbs battery cell expansion, reduces the weight and size of the power supply device, and prevents misalignment, enhancing the stability and efficiency of the power supply system.

Implementation Method 1

The separator is an elastomer, and both surfaces of a plate-shaped part are formed into uneven layers including different amounts of change in thickness with respect to a pressing force

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12424698B2Power supply device, electric vehicle comprising power supply device, and power storage device

Publication Date: 2025.09.23 SANYO ELECTRIC CO LTD

AI summary

A power supply device includes: battery block formed by stacking a plurality of battery cells in a thickness with separator interposed therebetween; a pair of end plates disposed on both end surfaces of battery block; and binding bar that is coupled to the pair of end plates and fixes battery block in a pressurized state via end plates. Separator is an elastomer, and both surfaces of plate-shaped part are formed into uneven layers having different amounts of change in thickness with respect to a pressing force.