Battery Cell Temperature Mapping via Lithium Content Gradients

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Solution Overview

Problem

Existing methods for assessing internal temperature distribution in lithium-ion batteries, such as the accelerating rate calorimeter (ARC), cannot accurately measure temperature gradients within the battery cell and do not simulate real-use conditions, leading to inadequate safety performance analysis.

Innovation Solution

A method and apparatus that assess internal temperature distribution by measuring lithium content at different positions on the negative electrode plate, calculating lithium intercalation reaction rates, and using the Arrhenius equation to determine temperature values, providing a comprehensive temperature gradient assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If accelerating rate calorimeter (ARC) is used to monitor temperature change, then thermal characteristics of the battery can be analyzed, but the test environment is harsh and cannot simulate real use conditions

Engineering Contradiction:

Improvethermal characteristics analysisVSAvoidreal use condition simulation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the test environment parameters from harsh adiabatic conditions to simulated real-use conditions with controlled temperature and humidity. The method uses electrochemical impedance spectroscopy (EIS) parameters at different frequencies to indirectly determine internal temperature, allowing the battery to be tested under normal operating conditions rather than requiring extreme adiabatic environments.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If accelerating rate calorimeter (ARC) is used to analyze thermal change, then voltage and resistance data can be obtained, but temperature gradient variation at different positions inside the battery cell cannot be provided

Engineering Contradiction:

Improvethermal runaway monitoringVSAvoidinternal temperature gradient measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the battery cell into multiple measurement zones by applying electrochemical impedance spectroscopy at different positions or using multiple measurement channels. By segmenting the measurement approach and using frequency-dependent impedance analysis, the method can infer temperature distribution and gradients at different locations within the battery cell, overcoming the limitation of single-point measurement.

Inventive Principle:

Principle #1Segmentation

3Productivity

If traditional methods are used to determine internal temperature, then overall battery pack thermal change can be analyzed, but accurate internal temperature distribution cannot be mastered

Engineering Contradiction:

Improvetesting efficiencyVSAvoidinternal temperature distribution accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces direct physical temperature measurement methods (such as embedded thermocouples or infrared imaging) with an electrochemical field-based method. By using electrochemical impedance spectroscopy and analyzing the frequency-dependent response of the battery, the system can non-invasively determine internal temperature distribution through electrical measurements, maintaining testing efficiency while improving measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Accurately determines internal temperature gradients, enhancing safety and reliability of lithium-ion batteries by offering precise temperature parameters for design improvements.

Implementation Method 1

calculating temperature values at different positions on the negative electrode plate respectively on the basis of the lithium intercalation reaction rate ratios at different positions on the negative electrode plate and the test environment temperature

Methodology Applied

Scientific EffectArrhenius equation:

Implementation Method 2

extracting a negative electrode plate of the target battery cell, and performing oxidation treatment on the negative electrode plate

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS20250226468A1Method and appartatus for assessing internal temperature distribution of battery cell, and device and storage medium

Publication Date: 2025.07.10 SVOLT ENERGY TECH (WUXI) CO LTD

AI summary

The internal temperature distribution of a battery cell is assessed by acquiring lithium content at different positions on a negative electrode plate of a target battery cell and a corresponding test environment temperature and determining lithium intercalation reaction rate ratios at different positions based on the lithium content at different positions on the negative electrode plate. Temperature values at different positions on the negative electrode plate are calculated based on the lithium intercalation reaction rate ratios at different positions on the negative electrode plate and the test environment temperature. An internal temperature distribution assessment result of the target battery cell is determined based on the temperature values at different positions on the negative electrode plate. Temperature gradients at different positions can be calculated by measuring the lithium content on a lithium-intercalated negative electrode plate, so that the internal temperature distribution assessment result of the battery cell can be obtained.