Phase-Change Heat-Absorbing Composite for Battery Thermal Runaway

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Solution Overview

Problem

Current heat-absorbing materials for battery cores are susceptible to damage from external forces, affecting their heat-absorbing performance and leading to thermal runaway, while existing skeletons that enhance compression resistance occupy space and reduce the amount of heat-absorbing material.

Innovation Solution

A heat-absorbing composite material comprising a skeleton with holes filled with a phase-change material, where specific parameters are defined to balance heat-absorbing and mechanical performance, ensuring the material maintains integrity under external forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat-absorbing material is arranged on the battery core surface, then heat-absorbing performance is improved, but mechanical strength deteriorates due to susceptibility to damage from external forces

Engineering Contradiction:
Improveheat-absorbing performanceVSAvoidmechanical strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent applies composite materials by combining a skeleton structure with heat-absorbing material to form an integrated heat-absorbing composite material. The skeleton provides mechanical strength and structural support, while the heat-absorbing material maintains its heat-absorbing functionality. This composite structure resolves the contradiction by allowing both components to coexist and contribute their respective properties without compromising either heat-absorbing performance or mechanical strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a composite structure where different regions have different functions: the skeleton region provides mechanical strength and structural support, while the heat-absorbing material region provides thermal management functionality. This spatial differentiation of properties allows the overall structure to simultaneously achieve both mechanical integrity and heat-absorbing performance.

Inventive Principle:
Principle #3Local quality

2Strength

If skeleton is added to enhance compression resistance, then mechanical strength is improved, but heat-absorbing performance deteriorates due to reduced amount of heat-absorbing material

Engineering Contradiction:
Improvecompression resistanceVSAvoidheat-absorbing performance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent resolves this contradiction by creating a composite material where the skeleton and heat-absorbing material are integrated into a unified structure. The skeleton provides the necessary compression resistance, while the heat-absorbing material fills or surrounds the skeleton to maintain adequate heat-absorbing capacity. The composite design allows both functions to be achieved simultaneously within the same component.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies porous materials by using a skeleton structure with holes that are filled with or surrounded by heat-absorbing material. This porous configuration allows the skeleton to provide mechanical strength while maintaining sufficient volume and surface area for the heat-absorbing material to perform its thermal management function effectively.

Inventive Principle:
Principle #31Porous materials

3Strength

If skeleton occupies space to provide structural support, then mechanical strength is improved, but heat-absorbing capacity deteriorates due to reduced volume for heat-absorbing material

Engineering Contradiction:
Improvestructural supportVSAvoidamount of heat-absorbing material
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent resolves this volume contradiction by integrating the skeleton and heat-absorbing material into a composite structure where both components occupy the same overall volume efficiently. The skeleton provides structural support with minimal volume occupation, while the heat-absorbing material utilizes the remaining space, achieving both structural integrity and adequate heat-absorbing capacity within the constrained volume.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies the nesting principle by placing heat-absorbing material within or around the skeleton structure. This nested configuration allows the heat-absorbing material to occupy the internal space of the skeleton, maximizing the use of available volume while maintaining the structural support function of the skeleton framework.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 composite material achieves excellent heat-absorbing performance and mechanical strength, preventing thermal runaway and ensuring the safety and efficiency of battery assemblies.

Implementation Method 1

heat generated by the battery core is taken away in a process such as a phase change of the heat-absorbing material

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

heat-absorbing material is arranged on a surface of the battery core, and heat generated by the battery core is taken away

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentEP4625619A1Heat-absorbing composite material, heat absorber, battery assembly, and electrical device
Publication Date: 2025.10.01 BYD CO LTD
  • EP4625619A1 patent drawingFigure 1
  • EP4625619A1 patent drawingFigure 2~4
  • EP4625619A1 patent drawingFigure 5~8

AI summary

The present disclosure provides a heat-absorbing composite material, a heat absorber, a battery assembly, and an electrical device. The heat-absorbing composite material includes a skeleton and a heat-absorbing material. The heat-absorbing material comprises a phase-change material. Holes of the skeleton are filled with the heat-absorbing material. A first surface of the heat-absorbing composite material is located between a second surface of the heat-absorbing composite material and a battery core. 0.2≤2252×r×ρ(S×x-a×H)×10-9/(0.6×Qc-360×cp×M)≤30, where r is the mass content of the phase-change material in the heat-absorbing material, ρ is the density of the heat-absorbing material in kg/m3, x is the thickness of the heat-absorbing composite material in mm, S is the area of the first surface in mm2, a is the area of an orthographic projection of the skeleton on the first surface in mm2, H is the thickness of the skeleton in mm, Qc is the capacity of the battery core in kJ, cp is the specific heat capacity of the battery core in kJ·kg-1·K-1, and M is the mass of the battery core in kg.