Foam Heat Insulating Layer for Battery Pack Thermal Safety
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Solution Overview
Problem
Conventional partition plates in battery packs, whether made of flame-retardant resin or inorganic refractory materials, fail to effectively withstand high temperatures during abnormal heat generation and are either heavy or costly, making them unsuitable for portable appliances.
Innovation Solution
Incorporating a heat insulating layer made of foam material that expands at temperatures between 110°C and 200°C, such as alkali metal silicates, to create a thick insulating barrier that suppresses heat conduction between batteries, while being lightweight and cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a partition plate comprising a flame-retardant resin material is used, then the battery pack can be made lightweight and inexpensive, but it is unable to withstand high temperature increase upon abnormal heat generation and cannot sufficiently stop heat conduction to adjacent batteries
Solution Approach 1:
The heat insulating layer is pre-installed between batteries in the battery pack before abnormal heat generation occurs. When temperature reaches 110°C or higher, the layer automatically expands to provide heat insulation, preventing heat conduction to adjacent batteries while maintaining the battery pack's lightweight and cost-effective characteristics
Solution Approach 2:
The heat insulating layer undergoes a parameter change in its thickness through thermal expansion. At normal temperatures, the layer maintains a thin profile to minimize weight and cost. When temperature reaches 110°C or higher, the layer expands significantly to increase thickness and provide effective heat insulation, thus resolving the contradiction between lightweight design and heat insulation performance
2Reliability
If a partition plate composed mainly of inorganic refractory material such as mica or ceramic is used, then the heat insulation performance is improved, but the battery pack becomes heavy and expensive
Solution Approach 1:
The heat insulating layer changes its physical state and thickness in response to temperature. At normal operating temperatures, the layer remains thin and lightweight. When abnormal heat generation occurs and temperature reaches 110°C or higher, the layer expands to provide sufficient heat insulation, thereby achieving reliable heat protection without the need for heavy inorganic refractory materials
Solution Approach 2:
The heat insulating layer is composed of a foam material that combines the benefits of lightweight construction with high-temperature response capability. This composite material approach allows the layer to remain lightweight under normal conditions while providing effective heat insulation when needed, avoiding the weight penalty of traditional inorganic refractory 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 heat insulating layer effectively prevents heat conduction from an abnormally heated battery to adjacent ones, providing a safe, lightweight, and cost-efficient battery pack solution.
Implementation Method 1
a foam material capable of foaming at a first predetermined temperature of 110° C. or more and less than 200° C.
Implementation Method 2
at least one heat insulating layer for separating the secondary batteries from one another
Implementation Method 3
the conduction of the heat to adjacent batteries
Data Source
AI summary
A battery pack includes: a plurality of secondary batteries; a housing for containing the secondary batteries; and at least one heat insulating layer for separating the secondary batteries from one another. The at least one heat insulating layer includes a foam material capable of foaming at a first predetermined temperature of 110° C. or more and less than 200° C. When the foam material foams, gas bubbles are produced in the heat insulating layer, so that the thickness of the heat insulating layer increases. The battery pack thus has excellent safety, exhibiting a high heat insulation effect in the event of abnormal heat generation of the batteries.