Thermal Expansion Separator for Battery Cell Heat Management

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Solution Overview

Problem

Conventional battery packs face issues with heat management, where abnormal heat generation in one battery cell can lead to thermal impact spread, causing temperature variations and potential damage among cells, and existing insulators may hinder normal heat dissipation, leading to elevated temperatures.

Innovation Solution

The battery module and pack incorporate thermal expansion materials with varying thermal conductivities, switching between high and low conductivity routes based on temperature, to connect adjacent cells and a cooling plate, inhibiting thermal impact spread and maintaining temperature stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a low-heat-conductive insulator is installed as a separator between adjacent battery cells, then heat transmission from abnormal cells is hindered, but most of the battery cell surface is covered with heat insulating material, reducing normal heat dissipation and causing temperature to rise

Engineering Contradiction:

Improvethermal impact spreadVSAvoidbattery cell temperature

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The thermal conductivity of the separator is made dynamically adjustable through the inclusion of phase change materials that alter their thermal properties at different temperature thresholds. This allows the separator to automatically transition between high thermal conductivity (for normal heat dissipation) and low thermal conductivity (for abnormal heat isolation) states, resolving the contradiction between preventing thermal impact spread and maintaining normal heat dissipation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The thermal conductivity parameter of the separator is changed based on temperature conditions. Under normal operating temperatures, the separator maintains high thermal conductivity to facilitate heat dissipation. When abnormal temperature rise occurs, the phase change materials trigger a parameter change to low thermal conductivity to isolate thermal impact, thus resolving the contradiction between the two opposing thermal management requirements

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a heat insulator is disposed between adjacent battery cells, then thermal impact spread is reduced, but variation in temperature among battery cells increases under normal use conditions, causing difference in battery characteristic

Engineering Contradiction:

Improvethermal impact spreadVSAvoidtemperature uniformity

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The separator's thermal conductivity is made dynamic rather than static, allowing it to adapt to different operating conditions. During normal use, high thermal conductivity maintains temperature uniformity across cells. During abnormal thermal events, low thermal conductivity isolates the affected cell, thus resolving the contradiction between maintaining temperature uniformity and preventing thermal impact spread

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The phase change materials in the separator provide automatic feedback-based thermal management. When temperature exceeds certain thresholds, the materials undergo phase changes that reduce thermal conductivity, creating a negative feedback mechanism that isolates abnormal thermal conditions while maintaining normal thermal coupling during standard operation, thereby resolving the contradiction

Inventive Principle:

Principle #23Feedback

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

This configuration effectively prevents excessive temperature rise and reduces temperature variations among battery cells under normal conditions while controlling thermal impact during abnormal heat generation.

Implementation Method 1

the first thermal expansion material member has a thermal conductivity lower than a thermal conductivity of the first heat transfer component and expands at a first predetermined temperature or higher

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11387502B2Battery module comprising a heat transfer component and a thermal expansion material between cells

Publication Date: 2022.07.12 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A battery module includes a first heat transfer component and a first thermal expansion material member that are disposed between the battery cells adjacent to each other. The first thermal expansion material member has a thermal conductivity lower than a thermal conductivity of the first heat transfer component and expands at a first predetermined temperature or higher, in which when temperature of the first thermal expansion material member is less than the first predetermined temperature, the adjacent battery cells are connected to each other via a high thermal conductive route including the first heat transfer component and having a first thermal conductivity, and in which when the temperature of the first thermal expansion material member reaches the first predetermined temperature or higher, the adjacent battery cells are connected to each other via a low thermal conductive route having a second thermal conductivity lower than the first thermal conductivity.