Battery and battery production method

Solution Overview

Problem

Batteries with multiple electrode bodies connected via conductive materials face challenges in achieving both adhesion between current collectors and active material layers and connectivity between electrode bodies, due to issues with oxide film formation and surface roughness.

Innovation Solution

The battery design features metal current collectors with distinct surface roughness levels for connection and laminate surfaces, where the connection surface has a ten-point average roughness of 1 μm or less and the laminate surface has a roughness greater than 1 μm, using solder and flux to facilitate adhesion and connectivity, and allowing for different materials for the current collectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the surface roughness of the current collector is increased to improve adhesion with the active material layer, then adhesion is improved, but oxide film formation increases and electrical connectivity deteriorates

Engineering Contradiction:

Improveadhesion between current collector and active material layerVSAvoidelectrical connectivity between electrode bodies

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The current collector is designed with different surface roughness characteristics for different functional regions: the laminate surface has high roughness (1 μm or more) to enhance adhesion with the active material layer, while the connection surface has low roughness (less than 1 μm) to minimize oxide film formation and ensure good electrical connectivity with the conductive material. This local differentiation resolves the contradiction by optimizing each surface for its specific function.

Inventive Principle:

Principle #3Local quality

2Reliability

If a conductive material is used to connect electrode bodies, then electrical connectivity is improved, but adhesion between current collector and active material layer may be compromised

Engineering Contradiction:

Improveconnectivity between electrode bodiesVSAvoidadhesion between current collector and active material layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The current collector is designed with different surface roughness characteristics for different functional regions: the laminate surface has high roughness (1 μm or more) to enhance adhesion with the active material layer, while the connection surface has low roughness (less than 1 μm) to minimize oxide film formation and ensure good electrical connectivity with the conductive material. This local differentiation resolves the contradiction by optimizing each surface for its specific function.

Inventive Principle:

Principle #3Local quality

3Reliability

If the surface roughness is kept low to reduce oxide film formation, then electrical connectivity is improved, but adhesion with the active material layer deteriorates

Engineering Contradiction:

Improveelectrical connectivity via conductive materialVSAvoidadhesion between current collector and active material layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The current collector is designed with different surface roughness characteristics for different functional regions: the laminate surface has high roughness (1 μm or more) to enhance adhesion with the active material layer, while the connection surface has low roughness (less than 1 μm) to minimize oxide film formation and ensure good electrical connectivity with the conductive material. This local differentiation resolves the contradiction by optimizing each surface for its specific function.

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 approach enhances adhesion between current collectors and active material layers while improving electrical connectivity between electrode bodies, reducing oxide film formation and contact resistance.

Implementation Method 1

adhesion between the current collectors and the resin is achieved by increasing the surface roughness of the current collectors in the extending parts

Methodology Applied

Scientific EffectMechanical interlocking:

Implementation Method 2

the conductive material may include solder

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS20230387557A1Battery and battery production method

Publication Date: 2023.11.30 TOYOTA JIDOSHA KK

AI summary

The battery of the present disclosure comprises a plurality of electrode bodies, wherein one of the electrode bodies and another of the electrode bodies are connected via a conductive material, each of the electrode bodies includes a metal current collector, an active material layer, and an electrolyte layer, the metal current collector has a connection surface which contacts the conductive material and a laminate surface which contacts the active material layer, and a ten-point average roughness of the laminate surface is less than a ten-point average roughness of the connection surface. According to the battery of the present disclosure, both adhesion between the metal current collector and the active material layer in the electrode body and connectivity between the electrode bodies via the conductive material can be achieved.