Battery Cell Pad Composite for Thermal Runaway Gap Retention

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Solution Overview

Problem

Existing battery modules face challenges in preventing rapid thermal runaway propagation between adjacent cells due to damage of buffer pads at high temperatures, which reduces the gap between cells and accelerates heat transfer, posing safety risks.

Innovation Solution

A battery module design incorporating a pad composite with swelling absorption pads made of materials like EPP or urethane, and a heat shielding pad made of epoxy-based, butyl-based, or vinyl chloride-based resin, which expands to maintain the gap and block heat transfer when the swelling pads shrink at elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a buffer pad made of EPP or urethane is used to absorb swelling, then the swelling absorption function is improved, but the heat resistance deteriorates causing the pad to contract at high temperatures

Engineering Contradiction:

Improveswelling absorption functionVSAvoidheat resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The buffer pad is divided into two distinct functional layers: a lower swelling absorption layer made of EPP or urethane material, and an upper heat-resistant layer made of heat-resistant foam material. This segmentation allows each layer to specialize in its respective function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The buffer pad uses a composite structure combining two different foam materials with complementary properties: EPP/urethane for swelling absorption and heat-resistant foam for thermal stability. This composite approach resolves the contradiction by integrating materials that individually excel at different functions.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the buffer pad is compressed to absorb swelling, then the swelling absorption function is improved, but the gap between cells reduces allowing faster heat propagation

Engineering Contradiction:

Improveswelling absorption functionVSAvoidheat propagation speed

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The buffer pad structure separates the swelling absorption function (lower layer) from the heat shielding function (upper layer), allowing the heat-resistant layer to maintain gap distance even when the swelling layer is compressed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat-resistant foam layer acts as an intermediary barrier between adjacent battery cells, maintaining thermal isolation even when the swelling absorption layer is compressed during cell expansion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If the buffer pad contracts due to heat damage, then the material degradation is inevitable, but the gap maintenance function is lost accelerating thermal runaway

Engineering Contradiction:

Improvethermal stabilityVSAvoidgap maintenance function

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The buffer pad is segmented into a heat-sensitive swelling absorption layer and a heat-resistant gap maintenance layer, ensuring that the upper layer continues to maintain gap distance even when the lower layer degrades thermally.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat-resistant foam layer is positioned beforehand to protect the swelling absorption layer from direct thermal exposure, cushioning against the harmful effects of high temperature before they can cause complete material failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution effectively absorbs volume expansion, maintains the gap between cells, and delays thermal runaway propagation, ensuring safety by minimizing heat transfer and preventing cell proximity even at elevated temperatures.

Implementation Method 1

a pair of swelling absorption pads compressed by a volume expansion of the plurality of battery cell caused by swelling

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

a heat shielding pad interposed between the pair of swelling absorption pads to block heat transfer between the neighboring battery cells

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

configured to expand at a reference temperature or above

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20240186608A1Battery apparatus

Publication Date: 2024.06.06 LG ENERGY SOLUTION LTD

AI summary

A battery module includes a cell stack including a plurality of battery cells and at least one pad composite interposed between neighboring battery cells; and a module case configured to accommodate the cell stack, wherein the pad composite includes a pair of swelling absorption pads compressed according to a volume expansion of the battery cell caused by swelling; and a heat shielding pad interposed between the pair of swelling absorption pads to block heat transfer between the neighboring battery cells and configured to expand at a preset reference temperature or above.