Battery Electrode Rounded Corners Reduce Stress

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Solution Overview

Problem

Existing battery designs face challenges in reducing the probability of active material detachment, which can lead to short circuits and reduced energy density due to stress concentration at the edges and corners of the battery components.

Innovation Solution

The battery design incorporates a first electrode layer with a current collector, an active material layer, and a solid electrolyte layer, where the solid electrolyte layer occupies the same area as the current collector and includes rounded portions to reduce stress concentration and prevent separation from the current collector, and a second electrode layer with a similar configuration to maintain spacing and prevent direct contact between current collectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the active material layer occupies the same area as the current collector, then the energy density is improved, but the active material is prone to detachment at the edges

Engineering Contradiction:
Improveenergy densityVSAvoidactive material detachment
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies curvature by rounding the corner portions of the electrode layers. Specifically, the solid electrolyte layer has rounded corner portions with a radius of curvature of 0.5 mm to 2.0 mm, which reduces stress concentration at the edges and prevents separation between layers, thereby preventing active material detachment while maintaining high energy density

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent implements beforehand cushioning by extending the solid electrolyte layer beyond the active material layer at the edges. This creates a protective border that cushions and distributes stress before it can reach the active material edges, preventing detachment while allowing the active material to occupy maximum area for high energy density

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If sharp corners are used in the electrode layers, then the manufacturing is simpler, but stress concentration occurs leading to separation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstress resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent modifies the electrode layer geometry by rounding corner portions instead of using sharp corners. The rounded corners with controlled radius (0.5-2.0 mm) distribute stress more evenly, preventing layer separation while adding minimal complexity to the manufacturing process

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If additional insulation layers are added between current collectors, then short circuit risk is reduced, but the device complexity increases

Engineering Contradiction:
Improveshort circuit preventionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the solid electrolyte layer multi-functional by having it serve both as the functional electrolyte component and as the insulation layer between current collectors. This eliminates the need for separate insulation layers, reducing structural complexity while maintaining short circuit prevention

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the insulation function with the solid electrolyte layer by extending it beyond the active material boundaries. This combination provides both ionic conduction and electrical insulation functions in a single layer, simplifying the overall battery structure

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3933965A1battery
Publication Date: 2022.01.05 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3933965A1 patent drawingFigure 1(a)~1(b)
  • EP3933965A1 patent drawingFigure 2(a)~2(b)
  • EP3933965A1 patent drawingFigure 3(a)~3(b)

AI summary

A battery includes a first electrode layer; and a second electrode layer disposed on the first electrode layer and serving as a counter electrode for the first electrode layer, wherein the first electrode layer includes a first current collector, a first active material layer, and a first solid electrolyte layer, the first active material layer is disposed to be in contact with the first current collector and to occupy a smaller area than the first current collector, the first solid electrolyte layer is disposed to be in contact with the first current collector and the first active material layer and to occupy the same area as the first current collector, the first active material layer faces the second electrode layer with the first solid electrolyte layer therebetween, and the first electrode layer includes a peripheral portion including a first rounded portion.