Power Storage Device Thermal Interface Gap Filling

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Solution Overview

Problem

When a cooler is provided outside a housing case in power storage devices, the heat conductive layer struggles to maintain contact with raised portions, leading to gaps and potential liquid ingress, which can cause corrosion due to inadequate sealing.

Innovation Solution

A power storage device design with a heat conductive layer sandwiched between the bottom of the lower case and the top surface of the cooler, featuring raised portions and a protrusion that spreads the layer to fill gaps, and a recess to enhance filling properties, ensuring consistent contact and preventing liquid entry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cooler is provided outside the housing case, then the sealing reliability deteriorates due to gaps between the cooler and lower case, but the ease of operation improves as the cooler can be independently accessed

Engineering Contradiction:
Improvecooler accessibilityVSAvoidsealing reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by creating localized protrusions on the cooler surface that make contact with specific localized regions of the heat conductive layer. This ensures reliable thermal contact and sealing at critical points without requiring the entire cooler surface to be perfectly flat or accessible, thus maintaining sealing reliability while allowing external cooler placement for operational accessibility.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the heat conductive layer is made thin to improve thermal contact, then the filling property deteriorates and gaps remain, but the thermal resistance improves

Engineering Contradiction:
Improvethermal resistanceVSAvoidfilling property
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent employs curvature by designing protrusions with rounded surfaces on the cooler. These curved protrusions naturally conform to and press into the heat conductive layer, ensuring complete filling of gaps and voids. The spherical/curved geometry allows the heat conductive material to be fully compressed and distributed around the protrusions, achieving both thin layer construction for low thermal resistance and complete filling for manufacturing precision.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design effectively fills gaps between the cooler and the lower case, improving thermal contact and preventing liquid ingress, thus reducing the risk of corrosion and enhancing the overall sealing and cooling efficiency.

Implementation Method 1

a heat conductive layer provided between the bottom and the top surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the heat conductive layer is spread by the protrusion toward the raised portions

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP4156379A1Power storage device
Publication Date: 2023.03.29 TOYOTA JIDOSHA KK
  • EP4156379A1 patent drawingFigure 1
  • EP4156379A1 patent drawingFigure 2
  • EP4156379A1 patent drawingFigure 3~4

AI summary

A power storage device includes a lower case (22) including a bottom (23), a cooler (30) provided below the bottom (23) and including a top surface (30a) facing the bottom (23), and a heat conductive layer (40) provided between the bottom (23) and the top surface (30a). The top surface (30a) includes a pair of raised portions (34), the raised portions (34) being provided away from each other and raised toward the bottom (23), and a protrusion (35) provided between the raised portions (34) and protruding toward the bottom (23).