Non-aqueous Electrolyte Battery with Cyclic Anhydride
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries fail to achieve sufficient reduction in direct current resistance (DCR) due to metal elution from metal components caused by hydrogen fluoride generation, which inhibits electrical contact between the exterior can and the negative electrode core.
Innovation Solution
Incorporating a cyclic carboxylic acid anhydride, such as diglycolic anhydride, into the non-aqueous electrolyte to suppress hydrogen fluoride generation, thereby maintaining effective electrical contact between the exterior can and the negative electrode core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposed portion of the negative electrode core is brought into contact with the inner surface of the exterior can to reduce resistance, then electrical contact is improved, but metal elution occurs causing insufficient resistance reduction
Solution Approach 1:
The patent introduces a specific non-aqueous electrolyte composition containing cyclic carboxylic acid anhydride as an intermediary substance between the metal components and the electrode. This electrolyte acts as a protective medium that prevents direct harmful interaction between metal elution and the electrical contact interface, thereby maintaining both low resistance and preventing metal contamination.
Solution Approach 2:
The patent modifies the chemical composition parameters of the non-aqueous electrolyte by adding cyclic carboxylic acid anhydride (0.1-5% by mass) to change the electrochemical environment. This parameter change suppresses metal elution reactions while maintaining good electrical contact properties, resolving the contradiction between contact quality and metal stability.
2Reliability
If lithium hexafluorophosphate is used in the non-aqueous electrolyte, then ionic conductivity is improved, but hydrogen fluoride generation causes metal elution
Solution Approach 1:
The patent converts the harmful effect of hydrogen fluoride generation into a beneficial outcome by adding cyclic carboxylic acid anhydride. This substance reacts with or suppresses the HF generation, transforming the harmful chemical reaction into a protective mechanism that prevents metal elution while maintaining ionic conductivity benefits from lithium hexafluorophosphate.
Solution Approach 2:
The cyclic carboxylic acid anhydride serves as a chemical intermediary that mediates between lithium hexafluorophosphate and metal components. It intercepts the harmful hydrogen fluoride byproducts before they can cause metal elution, allowing the electrolyte to maintain high ionic conductivity without the detrimental side effects.
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 results in a non-aqueous electrolyte secondary battery with low direct current resistance (DCR) and improved electrical contact, as evidenced by reduced DC resistance and enhanced charge-discharge cycle characteristics.
Implementation Method 1
the non-aqueous electrolyte contains lithium hexafluorophosphate and a cyclic carboxylic acid anhydride... to suppress hydrogen fluoride generation
Implementation Method 2
an exposed portion in which a surface of the negative electrode core is exposed is formed on an outer peripheral surface of the electrode assembly, the exposed portion is in contact with an inner surface of the exterior can
Data Source
Figure 1
AI summary
A non-aqueous electrolyte secondary battery (10) comprises: an electrode assembly (14) in which a positive electrode (11) and a negative electrode (12) are wound with a separator (13) therebetween; a non-aqueous electrolyte; and an outer can (16) that accommodates the electrode assembly (14) and the non-aqueous electrolyte. The negative electrode (12) has a negative electrode core (40), and a negative electrode mixture layer (41) provided to the surface of the negative electrode core (40). The electrode assembly (14) has, on the outer peripheral surface thereof, an exposed portion (42) in which the surface of the negative electrode core (40) is exposed, and the exposed portion (42) is in contact with an inner surface of the outer can (16). The non-aqueous electrolyte contains lithium hexafluorophosphate, and a cyclic carboxylic acid anhydride represented by formula (I). (in the formula, R1-R4 each independently represent H, an alkyl group, an alkene group, or an aryl group.)