Thermal Diffusion Sheet With In-Plane Heat Spreading for Battery Cells

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Battery cells in central regions of a module experience difficulty in heat diffusion, leading to local temperature rises and accelerated deterioration, which shortens the life of the battery system, and existing solutions do not fully address this issue.

Innovation Solution

A thermal diffusion sheet with heat conductive filler particles oriented parallel to the battery cell surface, providing effective heat dissipation by conducting heat along the surface or in longitudinal/lateral directions, and featuring a smooth surface for close contact with the battery cell to prevent stress concentration and expansion-induced breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a silicone sheet or graphite sheet is disposed between battery cells to suppress temperature rise, then the temperature rise of the battery system is suppressed, but the local heat diffusion in central region battery cells is insufficient

Engineering Contradiction:
Improvetemperature rise suppressionVSAvoidlocal heat diffusion effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses a composite material consisting of a polymer matrix and heat-conductive filler particles (such as aluminum oxide, silicon oxide, or boron nitride) to create a thermal diffusion sheet. This composite structure combines the flexibility and bonding capability of the polymer matrix with the high thermal conductivity of the filler particles, achieving both temperature suppression and effective local heat diffusion in central region battery cells.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The thermal diffusion sheet is designed with specific local properties: the heat-conductive filler particles are dispersed throughout the polymer matrix to create regions of high thermal conductivity where needed. The sheet can be positioned strategically between battery cells, particularly in central regions, to provide localized heat diffusion capability where it is most required.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If thin laminated battery cells are stacked to form modules to achieve high energy density and space saving, then energy density and space utilization are improved, but heat diffusion becomes more difficult in central region cells

Engineering Contradiction:
Improveenergy densityVSAvoidheat diffusion difficulty
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The thermal diffusion sheet acts as an intermediary layer between the thin laminated battery cells. It provides a dedicated heat transfer pathway that bridges the thermal isolation created by the compact stacking arrangement, allowing heat from central region cells to diffuse effectively without compromising the high energy density configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent introduces an additional thermal management dimension by inserting the thermal diffusion sheet between battery cells. This creates a new heat transfer dimension perpendicular to the cell stacking direction, enabling heat to escape from central region cells in multiple directions rather than being confined to the limited pathways available in the compact stacked arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 thermal diffusion sheet effectively diffuses heat generated by battery cells, reducing the likelihood of local temperature rises and prolonging the life of the battery system by suppressing stress concentration and expansion between adjacent cells.

Implementation Method 1

heat conductive filler particles oriented in a direction parallel to a surface of the battery cell... High heat generated locally at a position on the surface of the battery cell is thereby diffused in the direction parallel to the surface of the battery cell

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3748762B1Thermal diffusion sheet and battery system
Publication Date: 2024.02.14 SEKISUI POLYMATECH CO LTD
  • EP3748762B1 patent drawingFigure 1~2
  • EP3748762B1 patent drawingFigure 3~4
  • EP3748762B1 patent drawingFigure 5A~5E

AI summary

A thermal diffusion sheet and a battery system using the thermal diffusion sheet are provided. The thermal diffusion sheet effectively absorbs and diffuses heat in a high heat portion of a battery cell and thereby effectively cools the entire battery cell. A thermal diffusion sheet 20 is disposed so as to oppose a battery cell 10 included in a battery system 1 and diffuses heat generated by the battery cell 10. The thermal diffusion sheet 20 includes a polymer matrix containing heat conductive filler particles. In the thermal diffusion sheet 20, the heat conductive filler particles are oriented in a direction parallel to a surface of the battery cell 10.