Battery Thermal Management Testing via Temperature Matrix Degradation

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Solution Overview

Problem

The performance degradation of battery thermal management systems in electric vehicles leads to inefficiencies in charging and discharging cycles, power output, and potential safety risks such as thermal runaway and vehicle fires, necessitating a method to detect and prevent such failures.

Innovation Solution

A performance detection method that builds a current battery temperature matrix based on operating conditions, calculates temperature offsets relative to a reference matrix, and averages these offsets to determine a degradation factor, prompting timely maintenance when the system fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heat dissipation device is designed with high heat dissipation performance, then the battery thermal management effectiveness is improved, but the weight and volume of the device increase

Engineering Contradiction:
Improveheat dissipation performanceVSAvoiddevice weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent replaces traditional mechanical heat dissipation structures (heat sinks, fans, liquid cooling plates) with a phase change material-based thermal management system. The phase change material absorbs heat through phase transition (solid to liquid), eliminating the need for complex mechanical cooling components, thereby reducing device weight while maintaining effective heat dissipation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition properties of phase change materials (PCM) to absorb and store thermal energy from the battery. As the PCM transitions from solid to liquid state, it absorbs latent heat, providing passive thermal management without requiring additional active cooling mechanisms, thus reducing overall system weight.

Inventive Principle:
Principle #36Phase transitions

2Temperature

If a heat dissipation device is designed with high heat dissipation performance, then the battery thermal management effectiveness is improved, but the device volume increases

Engineering Contradiction:
Improveheat dissipation performanceVSAvoiddevice volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent replaces bulky mechanical heat dissipation components with compact phase change material modules. The PCM-based system requires no moving parts, large surface area heat sinks, or complex fluid circulation systems, achieving comparable or superior heat dissipation performance in a significantly reduced volume.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent integrates the phase change material within the battery pack structure itself, nesting the thermal management function within the existing battery housing and modules. This nested integration allows the heat dissipation system to occupy minimal additional space while effectively managing battery thermal conditions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If traditional heat dissipation methods are used, then the device structure is simple, but the heat dissipation performance is insufficient and causes thermal accumulation

Engineering Contradiction:
Improvedevice structureVSAvoidheat dissipation performance
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent employs phase change materials that undergo solid-liquid transitions at temperatures matching the battery's thermal management requirements. This phase transition mechanism provides high heat absorption capacity during critical thermal events, dramatically improving heat dissipation performance compared to traditional passive methods while maintaining relatively simple system architecture.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The patent utilizes composite phase change material structures that combine PCM with thermal conductive materials and encapsulation layers. These composite structures enhance heat transfer efficiency and thermal response while maintaining system simplicity, achieving superior heat dissipation without requiring complex multi-component assemblies.

Inventive Principle:
Principle #40Composite materials

4Temperature

If active cooling systems are implemented, then heat dissipation performance is improved, but energy consumption increases

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces active mechanical cooling systems (fans, pumps, compressors) with a passive phase change material-based system. The PCM absorbs heat automatically through phase transition without requiring external power input, eliminating energy consumption associated with active cooling components while maintaining effective heat dissipation performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The phase change material system provides self-regulating thermal management by automatically absorbing excess heat through phase transition when battery temperature rises. This self-service mechanism eliminates the need for externally controlled active cooling systems, reducing energy consumption while maintaining appropriate thermal conditions.

Inventive Principle:
Principle #25Self-service

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

Prevents performance degradation from affecting charging and discharging efficiency and safety by identifying thermal management system failures through a degradation factor, thereby improving battery pack reliability and safety.

Implementation Method 1

the battery is surrounded by a phase change material configured to absorb heat from the battery during a charge cycle or a discharge cycle

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP4382936B1Performance test method for battery thermal management system, and related device
Publication Date: 2026.05.06 GREAT WALL MOTOR CO LTD
  • EP4382936B1 patent drawingFigure 1
  • EP4382936B1 patent drawingFigure 2
  • EP4382936B1 patent drawingFigure 3

AI summary

A performance detection method of the battery thermal management system and a related device are provided in the disclosure, in which a current battery temperature matrix is built based on battery pack operating condition data of a current electric vehicle in a current preset time of period, the current battery temperature matrix is a three-dimensional matrix of battery pack output voltage subintervals, battery pack output current subintervals, and single-cell temperature maximum values in the battery pack. A quotient of each single-cell temperature maximum value in the current battery temperature matrix and corresponding reference single-cell temperature maximum value in a reference battery temperature matrix is formed to obtain a temperature offset of single cell, and all of temperature offsets of single cells are averaged to obtain an attenuation constant characterizing performance attenuation of the battery thermal management system. According to the disclosure, the performance detection of the battery thermal management system is realized based on the battery pack operating condition data of the electric vehicle, and it can be determined whether performance of the battery thermal management system degrades or fails according to the attenuation constant characterizing the performance attenuation of the battery thermal management system.