Secondary Battery Electrode Through Holes Separator Conductivity

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Solution Overview

Problem

The structure of a secondary battery with through holes on one face, an opposite face, and a side face, where a second electrode is laminated to the side faces for current collection, leads to probable deterioration of cycle characteristics due to unbalanced capacity and local battery reactions.

Innovation Solution

A secondary battery design featuring a first electrode with through holes, a first separator layer laminated to the inner walls, a second separator layer with lower conductivity on the outer faces, and a second electrode laminated to the surfaces of both separator layers, ensuring balanced capacity and stable current collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a second separator layer is laminated to the outer faces of the first electrode to continuously provide the second electrode across the through holes and face surfaces, then current collection is stabilized, but cycle characteristics deteriorate due to unbalanced capacity

Engineering Contradiction:

Improvecurrent collection stabilityVSAvoidcycle characteristics

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies different conductivity characteristics to different regions by using a first separator layer with higher carrier ion conductivity in the through hole regions and a second separator layer with lower carrier ion conductivity on the outer faces. This local differentiation allows current collection stability where needed while preventing capacity imbalance and cycle deterioration in other regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator structure is segmented into two distinct layers: a first separator layer lining the through holes and a second separator layer on the outer faces. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between current collection stability and cycle characteristics.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the second electrode is continuously laminated across the first separator layer and second separator layer, then current collection is simplified and capacity is increased, but local unbalanced capacity causes cycle deterioration

Engineering Contradiction:

Improvecurrent collection structureVSAvoidcycle characteristics

Core Design Contradiction:

Device complexityVSDuration of action of moving object

Solution Approach 1:

By assigning different conductivity properties to different separator layers in different locations, the patent creates local quality variations that prevent uniform current distribution issues. The lower conductivity second separator layer on the outer faces specifically addresses capacity balance while the continuous second electrode structure maintains simplicity.

Inventive Principle:

Principle #3Local quality

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 design balances the capacity of the first and second electrodes, enhancing cycle characteristics and preventing deterioration by stabilizing current collection and reducing local unbalanced capacity issues.

Implementation Method 1

conductivity of a carrier ion of the second separator layer is lower than conductivity of a carrier ion of the first separator layer

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11450890B2Secondary battery including first electrode with penetrating through holes, first separator layer on inner walls of through holes, and second separator layer on opposing faces on first electrode and method of producing the same

Publication Date: 2022.09.20 TOYOTA JIDOSHA KK

AI summary

A secondary battery made by laminating a separator layer and a second electrode to insides of a plurality of through holes of a first electrode, the first electrode having one face, an opposite face, a side face, and the through holes that penetrate from the one face to the opposite face, makes it possible to stably collect currents for the second electrode, and gives good cycle characteristics as a secondary battery. The secondary battery includes: the first electrode having the one face, the opposite face, the side face, and a plurality of the through holes that penetrate from the one face to the opposite face; a first separator layer that is laminated to inner walls of the through holes of the first electrode; a second separator layer that is laminated to at least one of the one face and the opposite face of the first electrode; and the second electrode that is laminated to surfaces of the first separator layer and the second separator layer, the surfaces being on the opposite side of other surfaces thereof which are in contact with the first electrode, the second electrode being continuously present across the surfaces, wherein conductivity of a carrier ion of the second separator layer is lower than that of the first separator layer.