Porous Li-Ion Electrode Tab Structure for Short-Circuit Reduction

Solution Overview

Problem

Lithium ion secondary batteries using metal porous bodies as current collectors face issues of short-circuit and contamination due to the non-mixture-impregnated portions, which can lead to electrical contact and stress-related problems during manufacturing and operation.

Innovation Solution

The lithium ion secondary battery electrode incorporates a current collector with a non-mixture-impregnated portion that has a surface roughness equal to or less than the mixture layer, featuring a tab portion with higher metal density and a tab converging portion with controlled surface roughness, and optionally filled with a filler to reduce contact and contamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a metal porous body is used as a current collector with a non-mixture-impregnated portion, then the energy density of the battery is improved, but short-circuit and contamination occur due to the uneven surface of the non-mixture-impregnated portion

Engineering Contradiction:

Improveenergy densityVSAvoidshort-circuit and contamination risk

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a tab converging portion with different surface properties (Ra ≤ 1/10 of mixture layer thickness) compared to the general non-mixture-impregnated portion. This localized surface treatment ensures that the critical tab area has smooth surfaces to prevent short-circuit and contamination, while the rest of the non-mixture-impregnated portion maintains its original structure for electrical connection functionality.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the non-mixture-impregnated portion has an uneven surface, then electrical connection is achieved, but stress concentration occurs on raised portions causing wire cutting

Engineering Contradiction:

Improveelectrical connectionVSAvoidwire cutting resistance

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by creating a tab converging portion with different surface properties (Ra ≤ 1/10 of mixture layer thickness) compared to the general non-mixture-impregnated portion. This localized surface treatment ensures that the critical tab area has smooth surfaces to prevent short-circuit and contamination, while the rest of the non-mixture-impregnated portion maintains its original structure for electrical connection functionality.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12261303B2Lithium ion secondary battery electrode and method for manufacturing the same

Publication Date: 2025.03.25 HONDA MOTOR CO LTD

AI summary

Provided are a lithium ion secondary battery electrode that occurrence of short-circuit and contamination can be reduced and the method for manufacturing such a lithium ion secondary battery electrode. An electrode used for a lithium ion secondary battery includes a current collector formed of a metal porous body. The current collector has a mixture layer impregnated with an electrode material mixture containing an electrode active material and a non-mixture-impregnated portion not impregnated with the electrode material mixture and including a tab portion and a tab converging portion. The surface roughness Ra of the non-mixture-impregnated portion is equal to or less than the surface roughness of the mixture layer.