Non-Aqueous Battery Electrolyte Layout for Lower Initial Resistance
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Solution Overview
Problem
The addition of isocyanate group-containing compounds to non-aqueous electrolytes in secondary batteries suppresses deterioration of charge-discharge cycle characteristics but increases initial resistance, necessitating a solution to manage this trade-off.
Innovation Solution
A non-aqueous electrolyte secondary battery design where the nitrogen element concentration from isocyanate group-containing compounds is higher on the outermost peripheral surface and inner wall of the battery case compared to the inner region, optimizing the application of these compounds to minimize resistance formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isocyanate group-containing compound is added to a non-aqueous electrolyte, then charge-discharge cycle characteristics are improved, but initial resistance increases
Solution Approach 1:
The patent applies isocyanate group-containing compounds selectively to specific locations: the outermost peripheral surface of the wound electrode assembly and the inner wall of the battery case. This localized application ensures that the compounds are present where they can most effectively suppress gas generation and protect against deterioration, while minimizing their presence in the bulk electrolyte where they would increase resistance. The nitrogen element concentration is controlled to be higher at these peripheral locations compared to the inner region, achieving local optimization of protective function versus resistance.
2Loss of substance
If an isocyanate group-containing compound is added to suppress deterioration, then gas generation is reduced, but the compound increases initial resistance
Solution Approach 1:
The patent implements local quality by concentrating isocyanate group-containing compounds at the outermost peripheral surface of the wound electrode assembly and on the inner wall of the battery case, where gas generation and swelling occur. By controlling the nitrogen element concentration distribution (A1 > B and/or A2 > B), the compound is positioned to maximize its protective effect against gas generation and swelling while minimizing its negative impact on initial resistance in the bulk electrolyte.
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
This approach effectively suppresses the increase in initial resistance while maintaining the benefits of isocyanate group-containing compounds in reducing charge-discharge cycle deterioration, as evidenced by lower resistance values and higher capacity maintenance rates.
Implementation Method 1
a nitrogen element concentration A1 derived from an isocyanate group-containing compound in an outermost peripheral surface of the wound electrode assembly
Data Source
AI summary
The present disclosure provides a non-aqueous electrolytic solution secondary battery capable of suppressing increase of initial resistance when an isocyanate group-containing compound is added to a non-aqueous electrolytic solution. The non-aqueous electrolytic solution secondary battery according to one embodiment of the present disclosure has: a wound type electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween; and a battery case for housing the wound type electrode body and the non-aqueous electrolytic solution. The relation between a nitrogen element concentration A1 derived from an isocyanate group-containing compound in an outermost circumferential surface 2a of the wound type electrode body, and a nitrogen element concentration B derived from an isocyanate group-containing compound in an inner region located further in than the outermost circumferential surface of the wound type electrode body, satisfies A1>B.