Battery Pack Venting Layout for Cell Expansion and Heat Isolation

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Solution Overview

Problem

Power storage devices face issues with upward expansion of power storage cells due to heat generation, which can affect vehicle interiors and transfer heat through discharged gas.

Innovation Solution

A power storage device configuration with a safety valve, exhaust path, cooler, and plate-shaped member to suppress gas movement and heat transfer, using restraint bands and adhesives to control cell expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power storage device is fixed to a vehicle with the top wall serving as a floor panel, then the device can be integrated into the vehicle structure, but upward expansion of power storage cells can affect the vehicle interior and transfer heat through discharged gas

Engineering Contradiction:

Improvevehicle integrationVSAvoidheat transfer to vehicle interior

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The accommodation case is divided into a lower case and an upper case that can be separated from each other. The upper case can be detached to allow access to the power storage cells, while the lower case remains fixed to the vehicle. This segmentation enables the top wall to serve as a floor panel while providing a pathway for discharged gas to escape away from the vehicle interior, preventing heat transfer to the vehicle interior.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A guide member is introduced as an intermediary component between the power storage cells and the upper case. The guide member includes a guide hole that directs discharged gas from the power storage cells into a discharge space, preventing the gas from directly entering the vehicle interior. This intermediary structure resolves the contradiction by providing a controlled pathway for gas discharge while maintaining the integrated vehicle structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If power storage cells generate heat and expand, then the cells respond to thermal conditions, but the upper surface expansion exerts influence on the vehicle interior

Engineering Contradiction:

Improvethermal responseVSAvoidexpansion influence on vehicle interior

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A cushioning member is provided between the power storage cells and the upper case to absorb expansion forces before they reach the vehicle interior. The cushioning member is positioned in advance to accommodate upward expansion of the power storage cells, preventing direct contact and potential damage to the vehicle interior while allowing the cells to respond normally to thermal conditions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If gas is discharged from the power storage cell, then the safety valve functions, but the discharged gas can heat the vehicle interior without countermeasures

Engineering Contradiction:

Improvesafety valve functionVSAvoidheat transfer through discharged gas

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The discharge path for gas is redirected from a vertical upward path (which would lead to the vehicle interior) to a horizontal or downward path through the guide member and discharge space. This dimensional change in the gas flow path allows the safety valve to function while preventing heated gas from entering the vehicle interior, resolving the heat transfer issue.

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

Effectively suppresses upward expansion and heat transfer to vehicle interiors by managing gas discharge and cooling, ensuring structural integrity and safety.

Implementation Method 1

a cooler that cools the power storage stack, the cooler being disposed below the power storage stack

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a safety valve being disposed in the lower surface; an exhaust path provided below the support portion and provided to be able to communicate with a space located below the safety valve

Methodology Applied

Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP4700912A1Power storage device

Publication Date: 2026.02.25 TOYOTA JIDOSHA KK

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AI summary

A power storage device includes: a power storage stack including a plurality of power storage cells (100) each having a lower surface (121) and an upper surface (123), a safety valve (SV) being disposed in the lower surface (121); a support portion that supports the power storage stack from below; an exhaust path (60) provided below the support portion and provided to be able to communicate with a space (S) located directly below the safety valve (SV); a cooler (200) that cools the power storage stack, the cooler (200) being disposed below the power storage stack; and a plate-shaped member disposed above the power storage stack and facing the upper surface (123) of each of the power storage cells (100).