Cylindrical Battery Pack Air-Gap Wall for Thermal Runaway Isolation

Solution Overview

Problem

Existing battery packs with mica plates and heat-resistant plastic walls between cylindrical battery cells have a complex structure and high manufacturing costs, which complicates the prevention of thermal runaway induction.

Innovation Solution

A battery pack design featuring a heat-resistant wall with heat-insulating recesses between cylindrical battery cells, forming air layers to reduce heat transfer and prevent thermal runaway, while maintaining a simpler structure and lower costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mica plates and heat-resistant plastic walls are disposed between adjacent battery cells to prevent thermal runaway induction, then safety is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveprevention of thermal runaway inductionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the heat-resistant material (mica plate) from direct contact with the battery cell surface and places it only at the bottom, allowing the side surfaces to be separated by simple partitions. This reduces the amount of heat-resistant material needed and simplifies the overall structure while maintaining thermal insulation effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The heat-resistant barrier is segmented into different components: a mica plate at the bottom and simple partitions at the sides. This segmentation allows each component to perform its specific function with minimal complexity, avoiding the need for a complete enveloping heat-resistant structure.

Inventive Principle:

Principle #1Segmentation

2Reliability

If mica plates and heat-resistant plastic walls are disposed between adjacent battery cells to prevent thermal runaway induction, then safety is improved, but manufacturing cost increases

Engineering Contradiction:

Improveprevention of thermal runaway inductionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the heat-resistant material (mica plate) from direct contact with the battery cell surface and places it only at the bottom, allowing the side surfaces to be separated by simple partitions. This reduces the amount of heat-resistant material needed and simplifies the overall structure while maintaining thermal insulation effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses simple partition structures made from less expensive materials for the side surfaces, reserving the more expensive mica plate only where it is most needed (at the bottom). This substitutes expensive materials with cheaper alternatives in less critical areas, reducing overall manufacturing cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If battery cells are disposed close to each other without gaps to increase capacity, then energy density is improved, but thermal runaway propagation risk increases

Engineering Contradiction:

Improvebattery capacityVSAvoidthermal runaway propagation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies different levels of thermal insulation to different locations: the bottom uses a mica plate for high-temperature protection, while the sides use simpler partitions. This local differentiation provides adequate thermal protection where needed while allowing battery cells to be closely spaced for maximum capacity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The heat-resistant barrier is segmented into different components: a mica plate at the bottom and simple partitions at the sides. This segmentation allows each component to perform its specific function with minimal complexity, avoiding the need for a complete enveloping heat-resistant structure.

Inventive Principle:

Principle #1Segmentation

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 battery pack effectively prevents thermal runaway induction with reduced manufacturing costs by using a heat-resistant wall with heat-insulating recesses to create air layers between adjacent cells, enhancing safety and efficiency.

Implementation Method 1

The corresponding one of the heat insulating recesses forms an air layer having a length (L) in a longitudinal direction of the corresponding one of the battery cells and a width (W) in a circumferential direction of the corresponding one of the battery cells

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS20240072349A1Battery pack

Publication Date: 2024.02.29 PANASONIC ENERGY CO LTD

AI summary

The induction of thermal runaway is prevented with lower manufacturing costs. In a battery pack, a heat resistant wall is disposed between cylindrical rechargeable battery cells and arranged in parallel to one another, and the heat resistant wall and the battery cells are housed in an exterior case. The heat resistant wall has heat insulating recesses in surfaces each facing the surface of a corresponding one of the battery cells, the heat insulating recesses each forming an air layer having a length extending in the longitudinal direction of the battery cells and a width extending in the circumferential direction of the battery cells.