Solid-State Battery Anode Structure for Swelling-Energy Balance

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Solution Overview

Problem

Existing batteries face challenges in achieving high energy density while minimizing volume variation during charge/discharge, particularly with silicon-based anode active materials due to significant expansion and contraction.

Innovation Solution

The all solid state battery design incorporates electrode bodies A and B connected in parallel, where body A includes a Si-based active material and body B includes an anode active material with lower expansion/contraction, with a capacity proportion of 25% to 60% for body A, and an operating voltage difference of 1 V or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If Si based active material is used to achieve high energy density, then energy density is improved, but volume variation during charge/discharge increases

Engineering Contradiction:

Improveenergy densityVSAvoidvolume variation

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

The battery is divided into multiple battery units, each containing electrode bodies with specific active materials. By segmenting the battery into units with different anode materials (Si-based and non-Si-based), the system achieves high energy density while controlling overall volume variation through proportional capacity distribution.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the parameter of anode active material composition by specifying that Si-based active material capacity should be 20-80% of total anode capacity. This parameter optimization allows the system to achieve high energy density while limiting volume variation during charge/discharge cycles.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If Si based active material is used, then capacity is improved, but structural stability during charge/discharge deteriorates

Engineering Contradiction:

ImprovecapacityVSAvoidstructural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The battery uses a composite electrode structure combining Si-based active material and non-Si-based active material in the anode. This composite approach leverages the high capacity of Si while the non-Si material provides structural stability, reducing expansion/contraction stress during lithium insertion/extraction.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the anode have different material compositions - some areas use Si-based material for high capacity while other areas use non-Si-based material for structural stability. This local quality differentiation allows simultaneous optimization of capacity and structural stability.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12463254B2Solid state battery

Publication Date: 2025.11.04 TOYOTA JIDOSHA KK

AI summary

An all solid state battery includes an electrode body A and an electrode body B connected in parallel and stacked along a thickness direction. The electrode body A includes a Si based active material, and the electrode body B includes an anode active material B having lower expansion/contraction than the Si based active material. A proportion of a capacity of the electrode body A with respect to a capacity of a total of the electrode body A and the electrode body B is 25% or more and 60% or less.