Hydrated Salt Composite Heat Storage for Battery Thermal Runaway
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Solution Overview
Problem
Current solutions for mitigating battery thermal runaway are complex, costly, and lack universality, with existing thermochemical heat storage models being cumbersome and not applicable to rapid heating scenarios during thermal runaway.
Innovation Solution
A hydrated salt composite for thermochemical heat storage is developed, comprising a high-thermal-conductivity porous adsorption carrier, a hydrated salt heat storage material, and a reinforcing material, which is designed to match the initial temperature of battery thermal runaway and have a high decomposition enthalpy, thereby effectively alleviating and curbing the spread of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If endothermic phase change materials (paraffin composite) are used for heat storage, then the structure is simple and no additional power source is required, but the phase change latent heat value (150 J/g) is much lower than the heat released during thermal runaway (about 880 J/g)
Solution Approach 1:
The patent utilizes the phase transition properties of hydrated salts, specifically the decomposition reaction that occurs at elevated temperatures. The hydrated salt undergoes a chemical phase transition where crystal water is released through decomposition, absorbing large amounts of heat (decomposition enthalpy of 1,100-1,300 J/g) during the process, thereby achieving high-temperature heat storage that matches thermal runaway conditions.
Solution Approach 2:
The patent creates a composite material system consisting of hydrated salt heat storage material, porous adsorption carrier, and reinforcement material. This composite structure combines the high heat storage capacity of hydrated salts with the structural integrity and thermal conductivity benefits of the carrier and reinforcement materials, achieving both high heat storage capacity and structural stability.
2Measurement precision
If existing kinetic models with Arrhenius formula are used for thermochemical heat storage, then the model parameters can be calculated, but the calculation is cumbersome and the model is not applicable to rapid heating scenarios during thermal runaway
Solution Approach 1:
The patent transforms the complex kinetic model parameters (activation energy, pre-exponential factor) into a simplified apparent specific heat capacity parameter through mathematical transformation. This parameter change allows the model to maintain accuracy in describing thermochemical heat storage while becoming computationally efficient and applicable to rapid heating scenarios during thermal runaway events.
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 hydrated salt composite exhibits a latent heat value of 110 J/g to 150 J/g and a decomposition enthalpy of 1,100 J/g to 1,300 J/g, effectively alleviating thermal runaway and inhibiting its spread in battery modules, while the simplified thermochemical heat storage model accurately describes the heat storage capacity with a relative error not exceeding 5%.
Implementation Method 1
the decomposition of internal materials of batteries is mainly divided into four parts: decomposition of solid electrolyte interface (SEI) film occurring at 70° C. to 120° C., decomposition of negative electrode occurring at 120° C. to 200° C., decomposition of positive electrode occurring at 200° C. to 230° C., and decomposition of electrolyte occurring at 230° C. to 243° C.
Implementation Method 2
Hydrated salt materials can undergo thermal decomposition at high temperatures (around 100° C.), and their crystal water can evaporate and escape, taking away a large amount of heat.
Implementation Method 3
a high-thermal-conductivity porous adsorption carrier
Data Source
AI summary
Provided are a hydrated salt composite for thermochemical heat storage, and a preparation method and use thereof. A hydrated salt is compounded with a high-thermal-conductivity material and a reinforcing material to obtain the hydrated salt composite for thermochemical heat storage.