Core-Shell Composite Binder for Electrode Sheet Heat Buffering
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Solution Overview
Problem
Existing thermal management systems for lithium/sodium-ion batteries are inadequate for controlling temperature at the electrode sheet level, leading to issues such as high-temperature electrolyte side reactions, reduced lithium ion migration, and thermal runaway, especially during fast charging and discharging.
Innovation Solution
A composite binder with a core-shell structure is introduced, where the core is a phase change material with a temperature range of -10°C to 70°C and the shell is a polymer binder, allowing for temperature control through phase changes that absorb or release latent heat, integrated into the electrode sheet manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling is used for thermal management at module/pack level, then cooling effect is achieved, but temperature control at electrode sheet level is not possible
Solution Approach 1:
The invention segments the thermal management function from the battery pack level down to the electrode sheet level by incorporating phase change material microcapsules directly into the binder of each electrode sheet. This allows independent temperature control at the sheet level rather than relying on centralized cooling systems.
Solution Approach 2:
The phase change material is encapsulated in microcapsules that are embedded within the polymer binder matrix of the electrode sheet. This nested structure allows the thermal management functionality to be integrated within the existing electrode structure without adding external complexity.
2Power
If high-temperature operation occurs, then battery power output is maintained, but electrolyte side reactions are aggravated and long-term cycle performance deteriorates
Solution Approach 1:
The invention changes the thermal parameters of the electrode sheet by incorporating phase change material with specific melting points (25-50°C) that activate at battery operating temperatures. This allows the material to absorb excess heat during high-power operation, maintaining temperature within the optimal range for both power output and cycle life.
3Productivity
If fast charging and discharging is performed, then charging speed is improved, but thermal shock occurs and temperature soars
Solution Approach 1:
The phase change material is pre-dispersed and encapsulated within the electrode sheet binder before battery assembly. This preliminary preparation ensures that the thermal management capability is already in place and activated immediately during fast charging operations, preventing temperature soars rather than reacting to them afterward.
4Ease of operation
If room temperature operation occurs, then battery is easy to operate, but thermal management capability is insufficient during temperature extremes
Solution Approach 1:
The polymer binder serves multiple functions: it provides structural binding for the electrode sheet and simultaneously hosts phase change material microcapsules for thermal management. This multi-functional design allows the electrode to maintain ease of operation at room temperature while gaining adaptability to temperature extremes through the phase change material's heat absorption and release capabilities.
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 composite binder effectively manages temperature fluctuations, enhancing battery performance by mitigating thermal shock and improving safety, fast charging capabilities, and maintaining capacity retention across varying temperatures.
Implementation Method 1
A core of the core-shell structure includes a phase change material, and a phase change temperature of the phase change material is −10° C. to 70° C.
Implementation Method 2
The composite binder can maintain its inherent bonding performance and undergo phase changes according to changes in external environmental temperature (battery temperature), thereby releasing or absorbing heat.
Data Source
AI summary
A composite binder, a preparation method thereof, and an electrochemical device are provided. The composite binder has a core-shell structure, wherein, a core of the core-shell structure is a phase change material, and a phase change temperature of the phase change material is −10° C. to 70° C. A shell of the core-shell structure is a polymer binder. The preparation method includes the following steps: subjecting a mixture of an oil phase and a water phase to shearing treatment and polymerization reaction for production. The oil phase includes the phase change material and a raw material of the polymer binder, and the raw material of the polymer binder at least includes a monomer. The water phase includes water and an emulsifier.