Battery Pack Partition Member With Phase-Change Cooling Channels

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Solution Overview

Problem

Existing partition members in secondary batteries are inadequate in safely cooling abnormally heated cells without causing thermal runaway in adjacent cells, and they often result in large and heavy battery systems due to external cooling components.

Innovation Solution

A partition member with a fluid having a boiling point of 80°C to 250°C is used, along with a flow channel for heat transfer, allowing for efficient heat removal and safe cooling of abnormally heated cells by controlling heat transfer direction, thereby preventing thermal runaway and reducing weight and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a partition member with coolant is used to cool abnormally heated cells, then thermal runaway of adjacent cells is prevented, but the cooling capacity is insufficient when coolant vaporizes only once

Engineering Contradiction:
Improveprevention of thermal runawayVSAvoidheat removal capacity
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The partition member utilizes the phase transition (vaporization) of coolant multiple times through a flow channel system. When a cell becomes abnormally heated, the coolant vaporizes to absorb heat, then the vapor moves through the flow channel to cooler regions where it condenses and returns to liquid form, ready to vaporize again. This cyclic phase transition enables continuous heat removal and significantly enhances the heat removal capacity compared to single-use coolant vaporization.

Inventive Principle:
Principle #36Phase transitions

2Power

If external cooling components are added to increase cooling capacity, then heat removal efficiency is improved, but the weight and size of the battery system increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidbattery system weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The invention merges the cooling function with the partition member structure itself. The partition member is designed to include coolant reservoirs and flow channels integrated into its body, eliminating the need for separate external cooling components. This integration maintains high cooling efficiency while reducing overall system weight and size, as the partition member serves dual purposes: mechanical separation of cells and active thermal management.

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If coolant is released instantly upon abnormal heating, then rapid cooling response is achieved, but the heat of vaporization cannot be sufficiently utilized

Engineering Contradiction:
Improvecooling response speedVSAvoidheat of vaporization utilization
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The flow channel system establishes continuous circulation of coolant between vaporization and condensation regions. When abnormal heating occurs, coolant vaporizes rapidly to provide immediate cooling response. The resulting vapor then continuously flows through the flow channel to cooler areas, condenses, and returns to the vaporization zone, creating a sustained cycle that fully utilizes the heat of vaporization over time rather than releasing coolant instantly and depleting the supply.

Inventive Principle:
Principle #20Continuity of useful action

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 solution effectively promotes safe cooling of abnormally heated cells within secondary batteries, preventing thermal runaway and achieving a lightweight, compact battery design.

Implementation Method 1

the partition member has, in the interior thereof, a fluid holding part capable of holding a fluid having a boiling point at normal pressure of 80°C to 250°C

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

the heat of vaporization of the sealed-in coolant such as water can be utilized yet more efficiently

Methodology Applied
Scientific EffectHeat absorption: Latent Heat

Implementation Method 3

the coolant such as water can be allowed to move towards a heat generation portion, without waste, by virtue of the capillary forces of the porous body

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 4

the partition member has a flow channel of the fluid extending along the surface direction

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3598566B1Partition member and battery pack
Publication Date: 2024.01.17 MITSUBISHI CHEM CORP
  • EP3598566B1 patent drawingFigure 1A~1B
  • EP3598566B1 patent drawingFigure 2
  • EP3598566B1 patent drawingFigure 3A~3C

AI summary

A partition member has a thickness direction and a surface direction perpendicular to the thickness direction, and which separates single cells that make up an assembled battery in the thickness direction, or a single cell that makes up the assembled battery in the thickness direction and a member other than the single cells. The partition member includes, in the interior thereof, a fluid having a boiling point at normal pressure of 80°C to 250°C, and a flow channel of the fluid extending along the surface direction. The fluid is held in a fluid holding part, and the fluid holding part is hermetically sealed by a packaging material.