Battery Pack Venting Layout and Cooling for Thermal Runaway

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Solution Overview

Problem

Existing thermal runaway protection for power batteries in new energy vehicles is primarily passive and lacks effective performance, posing safety concerns due to limited temperature resistance, heat release, and pressure control.

Innovation Solution

A battery pack design with integrated cooling components and pressure relief mechanisms, including exhaust passages and fireproof insulation, along with an active thermal runaway protection method that involves exhaust operations, thermal insulation, electrical insulation, and liquid cooling to manage and prevent thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive thermal runaway protection is used, then the structure is simple, but the protection performance is poor

Engineering Contradiction:
Improvethermal runaway protection performanceVSAvoidprotection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-configuring exhaust passages, cooling components, and insulation structures before thermal runaway occurs. The exhaust passages are pre-formed between the cell group pressure relief side and chamber inner wall, cooling components are integrated into the housing in advance, and insulation layers are pre-applied to partitions and exhaust passage walls, enabling immediate protective action when thermal runaway is detected

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses intermediary elements including the exhaust passage as a mediator for gas discharge, cooling components as intermediaries for heat removal, insulation layers as mediators for thermal isolation, and partitions as intermediaries for spatial separation. These intermediaries facilitate the protection function without requiring direct intervention in the cell chemistry

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the pressure relief side is spaced apart from the chamber inner wall to form exhaust passages, then gas discharge capability is improved, but the structural complexity increases

Engineering Contradiction:
Improvegas discharge capabilityVSAvoidhousing structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the exhaust passage function with the existing housing structure by utilizing the space between the cell group pressure relief side and chamber inner wall. The exhaust passage is not a separate component but is formed by the spatial relationship between existing structural elements, combining multiple functions (structural support, gas discharge pathway, thermal isolation) into a unified design

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If cooling components are integrated into the housing, then the cooling response is faster, but the manufacturing complexity increases

Engineering Contradiction:
Improvecooling response speedVSAvoidhousing manufacturing ease
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The cooling components are merged with the housing structure, where the housing serves dual purposes as both structural enclosure and cooling system integration platform. This integration eliminates separate cooling system assemblies and reduces the number of manufacturing steps while maintaining fast thermal response capability

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If partitions with fireproof insulating layers are used to separate cell groups, then thermal runaway spread prevention is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvethermal runaway spread preventionVSAvoidpartition manufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The partition employs composite material construction with fireproof insulating layers (such as ceramic coatings or fire-resistant composites) applied to the partition structure. This composite approach provides enhanced thermal isolation and fire resistance while maintaining the structural integrity and separation function of the partition

Inventive Principle:
Principle #40Composite materials

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 provides enhanced thermal runaway protection, improving safety by timely gas discharge, cooling, and insulation to prevent the spread of thermal runaway, thereby ensuring better operational safety and reliability of battery packs.

Implementation Method 1

a cooling component integrated into the housing and configured to cool the cell group in case of a temperature of at least part of the cell group higher than a preset temperature

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the exhaust passage is adapted to discharge gas generated by the cell group in case of thermal runaway of the cell group

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

an inner wall of the exhaust passage is provided with a fireproof flame-retardant layer with a fire-resistance rating not less than 200 °C

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

a thermal insulation layer is arranged between two adjacent cells, and formed of at least one of an aerogel material, a silicone rubber and a silicone foam

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4325628A1Battery pack and thermal runaway protection method
Publication Date: 2024.02.21 XIAOMI EV TECH CO LTD
  • EP4325628A1 patent drawingFigure 1~2
  • EP4325628A1 patent drawingFigure 3~4
  • EP4325628A1 patent drawing

AI summary

A battery pack and a thermal runaway protection method for a battery pack are provided. The battery pack includes: a housing (1) defining a chamber (141); a cell group (2) located in the chamber (14) and having a pressure relief side (21); and a cooling component (10) integrated into the housing (1) and configured to cool the cell group (2) in case of a temperature of at least part of the cell group (2) higher than a preset temperature. The pressure relief side (21) is spaced apart from an inner wall of the chamber (14) to define an exhaust passage (3) therebetween, and the exhaust passage (3) is adapted to discharge gas generated by the cell group (2) in case of thermal runaway of the cell group (2).