Battery Terminal Composite Structure for Sealing Integrity

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Solution Overview

Problem

Secondary batteries with laminated film outer packages experience a decline in sealing performance due to heat conduction from high thermal conductivity materials in the positive electrode terminal, leading to softened resin layers and reduced bonding strength.

Innovation Solution

A battery design featuring a laminated film outer package with a plate-like first metal layer and second metal layers on both surfaces of the first metal layer, which disperses heat from the terminal, preventing localized heat conduction to the resin layers and enhancing mechanical strength by using metals with lower thermal conductivity, such as titanium or stainless steel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the positive electrode terminal is made of high thermal conductivity material (Al alloy, copper, nickel or iron), then the mechanical strength is improved, but the heat is easily conducted to localized sites of the resin layer causing softening and reduced bonding strength

Engineering Contradiction:

Improvemechanical strength of terminalVSAvoidsealing performance of outer package

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The terminal is divided into multiple material layers: a first region made of high thermal conductivity material (Al alloy, copper, nickel or iron) for mechanical strength, and a second region made of low thermal conductivity material (polymer, ceramic, or glass) to block heat conduction to the resin layer. This segmentation allows each layer to perform its specific function independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal uses a composite structure combining materials with different thermal conductivity properties. The first region uses high thermal conductivity materials for strength, while the second region uses low thermal conductivity materials (polymer, ceramic, or glass) to prevent heat transfer to the resin layer, creating a composite material solution that balances mechanical strength and thermal insulation.

Inventive Principle:

Principle #40Composite materials

2Power

If heat is generated during welding or large current flow, then the terminal performs its electrical function, but the resin layer contacts the terminal and softens due to heat conduction, reducing bonding strength

Engineering Contradiction:

Improveelectrical current capacityVSAvoidbonding strength of resin layer

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The second region made of low thermal conductivity material (polymer, ceramic, or glass) acts as an intermediary layer between the high thermal conductivity terminal material and the resin layer. This intermediary blocks the heat path, preventing heat generated during welding or large current flow from reaching and softening the resin layer, thereby maintaining bonding strength while allowing high power operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the terminal is made with high thermal conductivity material, then the electrical conductivity is improved, but the bonded region of the laminated film is lowered in bonding strength due to heat softening

Engineering Contradiction:

Improveelectrical conductivity of terminalVSAvoidbonding strength of laminated film

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The terminal is segmented into a first region with high thermal conductivity material for electrical conductivity and a second region with low thermal conductivity material to protect the bonded region of the laminated film from heat-induced softening, maintaining both electrical performance and bonding strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal employs composite materials where the first region uses high thermal conductivity materials (Al alloy, copper, nickel or iron) for electrical conductivity, while the second region uses low thermal conductivity materials (polymer, ceramic, or glass) to prevent heat transfer to the bonded region of the laminated film, preserving bonding strength.

Inventive Principle:

Principle #40Composite materials

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 effectively prevents the softening of resin layers, maintains bonding strength, and enhances the mechanical strength of the terminal, thereby maintaining the sealing performance of the outer package.

Implementation Method 1

heat is easily conducted from the positive electrode terminal to localized sites of the resin layer... This structure makes it possible to disperse heat from the first metal layer of the terminal to wide ranges through the second metal layers... prevent a phenomenon that the heat from the first metal layer of the terminal is conducted to localized sites of the resin layer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10770695B2Battery

Publication Date: 2020.09.08 GS YUASA INT LTD

AI summary

A battery includes an outer package including a laminated film including one or more resin layers, a terminal, and a melt-bonding assisting member including a thermoplastic resin and extending along the terminal. The outer package includes a melt-bonded region at which the terminal is sandwiched between the one or more resin layers via the melt-bonding assisting member. The terminal includes an inner part, a sandwiched part, and an outer part arranged in a first direction. The battery has a discharge capacity of 10 Ah or more.