Laser-Welded Battery Casing with Localized Insulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrochemical batteries face challenges in achieving high reliability, low volume, and economical manufacturing with efficient energy storage capacity, particularly due to limitations in hermetic sealing and insulation at terminals.

Innovation Solution

The electrochemical cell features a metal casing with laser-welded walls, devoid of a thermoplastic layer at welding points, and includes electrically insulating layers on metal base bodies, along with microballs in the plastic insulation for enhanced electrical insulation and hermetic sealing, allowing for reliable and efficient energy storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermoplastic layer is applied on the inside of the casing at welding points, then electrical insulation is improved, but hermetic sealing reliability deteriorates due to inability to laser-weld

Engineering Contradiction:

Improvehermetic sealing reliabilityVSAvoidwelding process feasibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by having different surface conditions at different locations of the casing. The welding zones have bare metal surfaces for laser-welding capability, while other areas have thermoplastic coating for electrical insulation. This spatial differentiation resolves the contradiction between hermetic sealing reliability and ease of manufacture.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The casing surface is segmented into distinct functional zones: welding zones with bare metal for hermetic sealing, and insulation zones with thermoplastic coating for electrical isolation. This segmentation allows each zone to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

2Reliability

If multi-layer pouch-type elements are used, then electrical insulation is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveelectrical insulationVSAvoidcasing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of applying electrical insulation uniformly across the entire casing structure, the patent applies thermoplastic coating only in specific zones where insulation is needed, while maintaining bare metal surfaces in welding zones. This reduces structural complexity compared to multi-layer pouch-type elements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The casing combines metal base material with localized thermoplastic coating, creating a composite structure that provides both mechanical strength and electrical insulation where needed, without the complexity of multiple discrete layers.

Inventive Principle:

Principle #40Composite materials

3Reliability

If thicker metal base bodies are used for laser-welding, then hermetic sealing is improved, but weight increases

Engineering Contradiction:

Improvehermetic sealingVSAvoidcasing weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent optimizes the thickness parameter of the metal base body to a specific range that provides sufficient strength for hermetic sealing through laser-welding while minimizing weight. This parameter optimization resolves the contradiction between sealing reliability and weight.

Inventive Principle:

Principle #35Parameter changes

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 configuration ensures a high-reliability hermetic seal, low weight, and cost-effective manufacturing while optimizing energy density through improved electrical insulation and mechanical connection, surpassing the limitations of multi-layer pouch-type elements.

Implementation Method 1

the edges of the base bodies are connected by a weld bead to form the casing... at the location of the weld bead, the base bodies are free of the electrically insulating layer

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

microballs in the plastic insulation for enhanced electrical insulation and hermetic sealing

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS20230155187A1Electrochemical element for a battery and corresponding battery

Publication Date: 2023.05.18 SAFT GRP SA

AI summary

This electrochemical element for a battery, comprising a first electrode of a first polarity, a first terminal of the first polarity, a second electrode of a second polarity, a second terminal of the second polarity, and a casing comprising a first wall and a second wall. The first wall and the second wall each comprise a base body of metal and an electrically insulating layer. The electrically insulating layer comprises either a plastic coating or a layer resulting from a surface treatment. Each of the base bodies comprises a base body edge. The edges of the base bodies are joined by a weld bead to form the casing. At the location of the weld bead, the base bodies are free of the electrically insulating layer.