Lithium Ion Battery Electrode Salt Distribution and Aggregate Control
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in improving input/output characteristics due to uneven distribution and aggregation of lithium salts in the electrode mixture layer, leading to increased resistance and impaired Li ion supply to the active material.
Innovation Solution
A lithium ion secondary battery electrode with a foil-like current collector and an electrode mixture layer containing a particulate active material and lithium salt, where the lithium salt is distributed such that the ratio of the amount in the first region to the third region satisfies 0<S3/S1≤4, and the maximum particle diameter of lithium salt aggregates is less than 1 μm, ensuring efficient Li ion supply and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium salt is added to the electrode mixture layer, then the Li ion intake capability is improved, but the lithium salt tends to aggregate into large particles and distribute unevenly, leading to increased resistance
Solution Approach 1:
The patent changes the particle size parameter of lithium salt from conventional larger sizes to specifically 10 nm to 1 μm, and controls the aggregate size to be 1 μm or smaller. This parameter change prevents aggregation while maintaining Li ion intake capability, and ensures uniform distribution in the electrode mixture layer.
Solution Approach 2:
The patent applies local quality by ensuring lithium salt is uniformly distributed throughout the electrode mixture layer with controlled aggregate sizes, creating consistent local conditions for Li ion intake across the entire electrode rather than having concentrated aggregation points.
2Productivity
If lithium salt aggregate size is reduced, then Li ion supply efficiency is improved, but the complexity of controlling aggregate size increases
Solution Approach 1:
The patent establishes specific parameter ranges for lithium salt particle size (10 nm to 1 μm) and aggregate size (1 μm or smaller), transforming the complex control problem into a defined parameter specification that can be controlled through standard manufacturing processes.
3Power
If lithium salt is added to improve input/output characteristics, then battery performance is enhanced, but resistance in the electrode mixture layer increases due to aggregation
Solution Approach 1:
By changing the particle size parameter of lithium salt to 10 nm to 1 μm and controlling aggregates to 1 μm or smaller, the patent reduces electrode resistance while maintaining improved input/output characteristics, resolving the contradiction between power enhancement and resistance reduction.
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 the input/output characteristics of lithium ion secondary batteries by ensuring sufficient lithium salt presence near the current collector and preventing large aggregate formation, thereby improving Li ion supply and reducing electrode resistance.
Implementation Method 1
a lithium salt having a lithium ion intake capability is added to the electrode mixture layer
Implementation Method 2
the maximum particle diameter of aggregates of the lithium salt present in the electrode mixture layer is less than 1 μm
Data Source
AI summary
The present invention provides an art that can improve further battery performance of lithium ion secondary batteries in which a lithium salt is added to the interior of the batteries. A herein disclosed lithium ion secondary battery electrode is constituted by disposing, on a surface of a foil-like electrode current collector, an electrode mixture layer that contains a particulate electrode active material. With this electrode, a lithium salt having a lithium ion intake capability is added to the electrode mixture layer; dividing the electrode mixture layer into three equal regions, which are a first region, a second region, and a third region, in a thickness direction, an amount of the lithium salt component in the first region and an amount of the lithium salt component in the third region satisfy the relationship 0<S3/S1≤4; and a maximum particle diameter of aggregates of the lithium salt present in the electrode mixture layer is less than 1 μm.