Battery Stack Thermal Coupling With Spacer End Plates

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Solution Overview

Problem

Existing power supply devices face challenges in maintaining effective heat dissipation when the number of stacked battery cells increases, as the heat transfer sheet can interfere with end plates, leading to wrinkling and reduced thermal coupling.

Innovation Solution

The end plates are designed with spacer parts that protrude above the heat transfer sheet, allowing the pressing surfaces to float and avoid interference, while a low-friction sliding sheet and elastic heat transfer sheet maintain thermal coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of stacked battery cells is increased to achieve higher capacity, then the power supply device can provide more energy, but the overall length of the battery stack increases, causing end plates to interfere with the heat transfer sheet and generate wrinkles that reduce thermal coupling

Engineering Contradiction:
Improvenumber of battery cellsVSAvoidthermal coupling
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

A buffer member (spacer) is introduced as an intermediary element between the end plate and the heat transfer sheet. This buffer member prevents direct contact and interference between the end plate and heat transfer sheet, eliminating wrinkle formation while maintaining thermal coupling effectiveness. The buffer member acts as a mediator that absorbs dimensional changes without compromising the thermal interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The space between the end plate and heat transfer sheet is segmented by introducing a buffer member, creating distinct functional zones: the buffer member handles dimensional accommodation while the heat transfer sheet maintains thermal coupling. This segmentation allows each component to perform its specific function without interference from the other.

Inventive Principle:
Principle #1Segmentation

2Temperature

If the battery stack is compressed to ensure thermal coupling with the heat transfer sheet, then heat dissipation efficiency is improved, but the pressing surfaces of end plates are obstructed by the heat transfer sheet, preventing effective compression

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcompression operation
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The buffer member serves as a mediator that enables the pressing operation to proceed without obstruction. It allows the end plate's pressing surface to compress the battery stack effectively while preventing the heat transfer sheet from being directly obstructed, thus maintaining both compression effectiveness and thermal coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer member is pre-positioned between the end plate and heat transfer sheet before compression occurs. This preliminary placement ensures that during the compression operation, the pressing force is transmitted effectively through the buffer member to compress the battery stack, while the heat transfer sheet remains free from obstruction and maintains proper thermal contact.

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If a long heat transfer sheet is used to ensure all battery cells are placed on it, then complete thermal coverage is achieved, but the end plate interferes with the heat transfer sheet during compression, causing wrinkles and reducing thermal coupling

Engineering Contradiction:
Improveheat transfer sheet coverage areaVSAvoidthermal coupling quality
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The buffer member acts as a necessary intermediary that allows the use of a sufficiently long heat transfer sheet to cover all battery cells while preventing the end plate from interfering with it during compression. This mediator enables both complete thermal coverage and maintenance of thermal coupling quality without wrinkle formation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures reliable thermal coupling and efficient heat dissipation by preventing interference between the end plates and heat transfer sheet, even with changes in battery stack length due to cell expansion.

Implementation Method 1

a heat transfer sheet interposed between an upper surface of the thermal plate and a lower surface of the battery stack to bring the thermal plate and the battery stack into a thermally coupled state

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4012820B1Power supply device, electric vehicle using same, and power storage device
Publication Date: 2025.10.29 SANYO ELECTRIC CO LTD
  • EP4012820B1 patent drawingFigure 1
  • EP4012820B1 patent drawingFigure 2
  • EP4012820B1 patent drawingFigure 3~4

AI summary

In order to ensure heat dissipation by appropriately bringing a battery stack into a thermally coupled state with a heat transfer sheet even when the number of stacked battery cells increases, power supply device (100) includes a plurality of battery cells (1) each having an exterior can in a prismatic shape, a pair of end plates (20) having pressing surfaces that press both side end surfaces of battery stack (10) in which the plurality of battery cells (1) are stacked, a plurality of fastening members each of which has a plate shape extended in a stacking direction of the plurality of battery cells (1) and is disposed on opposing side surfaces of battery stack (10) to fasten end plates (20) to each other, thermal plate (50) for placing battery stack (10) on an upper surface side to dissipate heat from battery stack (10), and heat transfer sheet (40) interposed between an upper surface of thermal plate (50) and a lower surface of battery stack (10) to bring thermal plate (50) and battery stack (10) into a thermally coupled state. A part of a lower surface of each of end plates (20), the part facing heat transfer sheet (40), is disposed at the same height as or above an upper surface of heat transfer sheet (40).