Nonaqueous Electrolyte Battery with Optimized Electrolyte Ratio
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Solution Overview
Problem
Lithium secondary batteries experience performance degradation due to electrolyte depletion during repetitive charge and discharge cycles, particularly at high temperatures and low temperatures, leading to capacity loss and increased resistance.
Innovation Solution
A nonaqueous electrolyte secondary battery configuration with a specific electrolyte amount ratio (A/B) between surplus and intra-electrode body electrolyte, and a positive electrode active material with high DBP absorption, ranging from 30 to 50 ml/100 g, to maintain electrolyte balance and prevent ion shortage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrolyte amount in the electrode body is increased, then electrolyte depletion is suppressed, but the battery resistance increases and charge-discharge characteristics deteriorate
Solution Approach 1:
The invention applies local quality by differentiating electrolyte distribution between intra-electrode body electrolyte (B) and surplus electrolyte (A). Instead of uniformly increasing electrolyte throughout the system, the patent optimizes the specific proportion of electrolyte within the electrode body structure versus external reservoir, allowing sufficient electrolyte for ion transport while maintaining overall battery performance
2Productivity
If the electrolyte amount is reduced, then battery resistance decreases, but electrolyte depletion occurs during repetitive charge and discharge cycles
Solution Approach 1:
The invention implements preliminary action by pre-establishing an optimized electrolyte amount ratio (A/B) before the battery enters service. This pre-configured ratio ensures that sufficient electrolyte is available from the outset to prevent depletion during repetitive cycles, while simultaneously maintaining low resistance for high productivity. The surplus electrolyte acts as a buffer that replenishes electrolyte lost during operation
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 configuration enhances high-temperature charge-discharge cycle characteristics and suppresses low-temperature high-rate charge-discharge cycle degradation, maintaining battery performance and capacity.
Implementation Method 1
DBP absorption of a positive electrode active material that constitutes the positive electrode is equal to or higher than 30 (ml/100 g)
Implementation Method 2
charge and discharge are performed by the migration of lithium-ions between a positive electrode and a negative electrode
Implementation Method 3
the intra-electrode body electrolyte amount can be promptly restored by replenishing the electrolyte from the surplus electrolyte
Data Source
AI summary
It is an object of the present invention to provide a nonaqueous electrolyte secondary battery with superior high-temperature charge-discharge cycle characteristics as well as superior low-temperature high-rate charge-discharge cycle characteristics. A nonaqueous electrolyte secondary battery 100 according to the present invention has an electrode body 80 which includes a positive electrode and a negative electrode, and a battery case 50 which houses the electrode body 80 together with a nonaqueous electrolyte, wherein among the nonaqueous electrolyte housed in the battery case 50, an electrolyte amount ratio (A/B) between a surplus electrolyte amount (A) that exists outside the electrode body 80 and an intra-electrode body electrolyte amount (B) impregnating the electrode body 80 ranges from 0.05 to 0.2, and DBP absorption of a positive electrode active material that constitutes the positive electrode is equal to or higher than 30 (ml/100 g).