Hydrogel Heat Absorber for Battery Thermal Runaway Suppression
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Solution Overview
Problem
Existing battery exterior films for secondary batteries have limited heat absorption capacity due to thickness and flexibility constraints, and do not effectively manage temperature rise or provide sufficient flame shielding, leading to potential thermal runaway and safety issues.
Innovation Solution
A heat absorber comprising a bag filled with an organic-inorganic composite hydrogel, which has a low heat absorption starting temperature, excellent heat absorption capacity, and cushioning properties, designed to be used between battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a battery exterior laminated film is used as a heat absorber, then the film can provide some heat absorption, but the amount of heat-absorbing material is limited due to film thickness restrictions, resulting in insufficient heat absorption effect
Solution Approach 1:
The invention divides the heat absorption function into two separate components: a battery exterior film for structural protection and a separate heat absorber containing a large amount of heat-absorbing material. This segmentation allows the heat absorber to be optimized for maximum heat absorption capacity without being constrained by the thickness limitations of the battery exterior film.
Solution Approach 2:
The invention introduces a separate heat absorber as an intermediary component between the battery exterior film and the thermal runaway source. This heat absorber acts as a dedicated thermal management layer that can absorb large amounts of heat without interfering with the structural function of the battery exterior film.
2Temperature
If calcium sulfate dihydrate is used as a heat-absorbing material with heat absorption starting temperature of 120°C, then low heat absorption starting temperature is achieved, but molding is difficult because endothermic reaction occurs from 120°C
Solution Approach 1:
The invention performs preliminary action by pre-mixing the calcium sulfate dihydrate with other materials in a dry state before molding. This allows the mixture to be easily molded at room temperature or low temperature, and the endothermic reaction of calcium sulfate dihydrate occurs after molding during thermal runaway, providing heat absorption without interfering with the molding process.
3Ease of manufacture
If molding is performed at 80°C to avoid endothermic reaction of calcium sulfate dihydrate, then molding becomes possible, but the battery exterior film does not have enough strength to be used alone
Solution Approach 1:
The invention separates the structural function from the heat absorption function. The battery exterior film provides structural strength and protection, while the separate heat absorber provides thermal management. This segmentation allows each component to be optimized independently - the film for strength and the heat absorber for heat absorption capacity.
4Reliability
If existing battery exterior films are used for heat absorption, then flame retardancy is provided, but temperature control before thermal runaway, battery cell expansion, and flame shielding properties are not considered
Solution Approach 1:
The invention creates a multi-functional thermal management system where the heat absorber with phase change material provides multiple functions: temperature control before thermal runaway, flame shielding during thermal runaway, and cushioning for battery cell expansion. This universal heat absorber design addresses multiple safety concerns that existing single-function battery exterior films cannot handle.
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 absorber effectively suppresses temperature rise and provides flame retardancy, enhancing the safety of secondary battery modules by preventing thermal runaway and protecting adjacent cells.
Implementation Method 1
a heat absorber containing a bag and a hydrogel exhibits a low heat absorption starting temperature and is excellent in heat absorption amount
Implementation Method 2
the hydrogel can absorb and release aqueous solvent in response to a temperature change, has excellent cushioning properties
Data Source
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AI summary
The present disclosure is aimed to provide a heat absorber with a low heat absorption starting temperature and excellent heat absorption amount, flame retardancy, and cushioning properties, and a secondary battery module including the heat absorber. The present disclosure provides a heat absorber including a bag capable of being filled with content and a hydrogel to fill the bag as the content, in which the hydrogel has a three-dimensional network structure and is synthesized using a water-soluble organic monomer as a reaction material. The heat absorber in the present disclosure is useful, in particular, as a heat absorber for secondary batteries.