Comb-Type Electrode Design for Solid-State Battery Dead Space Reduction

Solution Overview

Problem

Conventional solid state batteries face issues with increased dead space due to bending of tab welding parts, leading to decreased capacity density and internal stress in the electrode group structure, which affects manufacturing yield and battery properties.

Innovation Solution

The implementation of a comb-type electrode design where negative and positive electrode layer sheets are alternately stacked with a solid state electrolyte in between, featuring notch parts and bent connecting parts that reduce dead space and stress differences, and a zigzag arrangement of the electrolyte to enhance stacking efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high basis weight electrodes are stacked for higher capacity, then battery capacity increases, but dead space increases due to bending of tab welding part

Engineering Contradiction:

Improvebattery capacityVSAvoiddead space

Core Design Contradiction:

Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The electrode structure is segmented into a flat electrode body portion and a separate bent tab welding portion. The tab welding part is divided into a connection region (connected to the electrode) and a welding region (for external connection), allowing the bending to be isolated to a specific segment that does not affect the flatness of the main electrode stacking area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bent tab welding portion is extracted as a separate functional element from the main electrode body. The tab welding part is positioned separately from the stacked electrode layers, with only the necessary connection portion attached to the electrode, while the bent portion extends outward to accommodate welding operations without interfering with electrode stacking.

Inventive Principle:

Principle #2Taking out (Extraction)

2Quantity of substance

If number of stacked layers increases for higher capacity, then battery capacity increases, but dead space increases due to bending of tab welding part

Engineering Contradiction:

Improvebattery capacityVSAvoidstacking structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The electrode structure is segmented into a flat electrode body portion and a separate bent tab welding portion. The tab welding part is divided into a connection region (connected to the electrode) and a welding region (for external connection), allowing the bending to be isolated to a specific segment that does not affect the flatness of the main electrode stacking area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tab welding part utilizes a different spatial dimension by extending outward from the stacked electrode layers. Instead of bending within the stacking plane, the tab welding portion bends in a direction perpendicular to the electrode stacking direction, effectively using the third dimension to accommodate the welding structure without increasing dead space in the stacking direction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If bending of tab welding part occurs, then connection flexibility improves, but internal stress remains after press forming

Engineering Contradiction:

Improveconnection flexibilityVSAvoidelectrode group structure

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The bent tab welding portion is extracted as a separate functional element from the main electrode body. The tab welding part is positioned separately from the stacked electrode layers, with only the necessary connection portion attached to the electrode, while the bent portion extends outward to accommodate welding operations without interfering with electrode stacking.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The electrode structure is designed with a preliminary configuration where the tab welding part is already bent in the desired direction before press forming. This preliminary bending in the opposite direction to the press forming force counteracts the stress that would otherwise be generated during pressing, allowing the internal stress to be reduced or eliminated after the pressing process.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS11522227B2Secondary battery and comb-type electrode

Publication Date: 2022.12.06 HONDA MOTOR CO LTD

AI summary

Provided is a secondary battery and a comb-type electrode. A negative electrode layer sheet formed by stacking a negative electrode active material layer on two surfaces of a negative electrode current collector and a positive electrode layer sheet formed by stacking a positive electrode active material layer on two surfaces of a positive electrode current collector are alternately stacked, and an electrolyte body is interposed between the negative electrode layer sheet and the positive electrode layer sheet adjacent in a stacking direction. Each of the negative electrode current collector and the positive electrode current collector includes a bent connecting part sandwiching a notch part and formed by bending two sides in directions opposite to each other. The bent connecting parts of the negative electrode current collectors adjacent in the stacking direction and the bent connecting parts of the positive electrode current collectors adjacent in the stacking direction are connected.