Electrochemical apparatus and electronic apparatus
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Solution Overview
Problem
Lithium-ion batteries face performance degradation due to mismatched raw materials, leading to poor high-temperature storage and overcharge protection, which can result in heat generation, swelling, deformation, or even explosion.
Innovation Solution
An electrochemical apparatus with a negative electrode having a specific adhesion strength and an electrolyte containing propionate, which includes rubber and specific compounds, enhances the interfacial stability and prevents the negative electrode from breaking during high-temperature storage, thereby improving high-temperature storage performance and overcharge protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional raw materials are used in the negative electrode, then manufacturing cost is reduced, but high-temperature storage performance deteriorates due to poor interfacial stability
Solution Approach 1:
The patent uses a composite binder system comprising both polyvinylidene fluoride (PVDF) and carboxymethyl cellulose (CMC) in the negative electrode mixture layer. This composite material approach combines the advantages of both binders: PVDF provides good electrochemical stability and electron conductivity, while CMC enhances adhesion strength and structural integrity at high temperatures. The synergistic effect of these two materials resolves the contradiction by achieving both high-temperature storage performance and ease of manufacture.
Solution Approach 2:
The patent optimizes the weight ratio of PVDF to CMC within the range of 95:5 to 50:50, and controls the adhesion strength of the negative electrode active substance between 100-500 N/cm². By adjusting these parameters, the patent achieves optimal interfacial stability at high temperatures while maintaining manufacturability. The specific parameter ranges are determined through systematic optimization to balance performance and manufacturing ease.
2Reliability
If traditional electrolyte composition is used, then device complexity is reduced, but overcharge protection performance deteriorates
Solution Approach 1:
The patent introduces propionate as an intermediary substance in the electrolyte composition. Propionate acts as a mediator that forms protective films on the electrode surfaces during charging, particularly at overcharge conditions. This intermediary substance enables overcharge protection by creating a stable interface layer that prevents harmful reactions, while the electrolyte composition remains relatively simple and manageable.
Solution Approach 2:
The patent specifies that propionate should constitute 5-65% by weight of the total electrolyte composition. By controlling this parameter within the optimal range, the patent achieves effective overcharge protection performance. The parameter optimization ensures that sufficient propionate is present to form protective films, while excessive amounts are avoided to prevent other issues, thus balancing performance with composition simplicity.
3Reliability
If negative electrode active substance with high adhesion strength is used, then high-temperature storage performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines a specific range for adhesion strength (100-500 N/cm²) and provides guidance on achieving this through binder composition and processing parameters. By specifying this range rather than requiring an exact value, the patent accommodates normal manufacturing variations while still ensuring high-temperature storage performance. The binder system composition is optimized to naturally achieve adhesion strength within this range, reducing the need for extremely precise manufacturing control.
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 solution significantly reduces swelling and deformation rates during high-temperature storage and overcharge conditions, ensuring the battery's safety and performance by stabilizing the interface between the negative electrode and electrolyte.
Implementation Method 1
the electrolyte includes propionate... enhances the interfacial stability and prevents the negative electrode from breaking during high-temperature storage
Implementation Method 2
the negative electrode mixture layer includes rubber... significantly reduces swelling and deformation rates during high-temperature storage and overcharge conditions
Data Source
AI summary
An electrochemical apparatus includes a positive electrode, a negative electrode, and an electrolyte, the negative electrode includes a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector, the negative electrode mixture layer includes a negative electrode active substance, there is specific adhesion strength for the negative electrode active substance, and the electrolyte includes propionate. The electrochemical apparatus has improved high-temperature storage performance and overcharge protection performance.