Battery Can Seam Welding Structure for Triple Laser Joining

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Solution Overview

Problem

The manufacturing process of cylindrical battery cells is labor-intensive and costly due to individual welding of the current collector plate, cap, and sidewall member, and assembly errors can cause laser penetration into the can, damaging the electrode assembly.

Innovation Solution

A welding structure that integrates the welding of the current collector plate to the can and the cap to the sidewall member into a single process, using a mutual contact structure for alignment and close contact, preventing laser penetration through triple welding, and employing a current collector plate with higher thermal conductivity to disperse welding heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual welding processes are used for connecting the current collector plate to the cap and the cap to the sidewall member, then welding reliability is improved, but production efficiency deteriorates and manufacturing cost increases

Engineering Contradiction:

Improvewelding reliabilityVSAvoidproduction efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the welding of the current collector plate to the cap and the cap to the sidewall member into a single integrated welding process. The cap is designed with a protrusion that fits into a recess of the sidewall member, creating a pre-aligned assembly that can be welded in one operation, thereby improving production efficiency while maintaining welding reliability through the mutual contact structure

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If laser welding is performed on crudely assembled components with gaps, then production efficiency is improved, but the laser penetrates directly into the can causing damage to the electrode assembly

Engineering Contradiction:

Improveproduction efficiencyVSAvoidlaser penetration damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by designing the cap with a protrusion and the sidewall member with a corresponding recess that create a mutual contact structure before welding. This pre-alignment prevents gaps between components, blocking the laser path and preventing laser penetration damage to the electrode assembly while still allowing efficient laser welding to proceed

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If the current collector plate is welded to the cap and sidewall member, then electrical connection is improved, but assembly complexity increases and alignment precision deteriorates

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses asymmetry in the design of the cap protrusion and sidewall member recess, creating a unique fit that simplifies assembly. The asymmetric mutual contact structure provides self-alignment, reducing assembly complexity while ensuring proper alignment for reliable electrical connection through the current collector plate

Inventive Principle:

Principle #4Asymmetry

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 increases production efficiency, reduces costs, enhances weld durability, and prevents damage to the electrode assembly by ensuring secure assembly and effective heat dissipation during the welding process.

Implementation Method 1

employing a current collector plate with higher thermal conductivity to disperse welding heat

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the process of welding the current collector plate to the can and the process of welding the cap to the sidewall member are integrated into a single welding process

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 3

When a laser is irradiated for assembly with such a gaps present, the laser may penetrate directly into the can

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20240413491A1Seam Welding Structure of Battery Can, Current Collecting Plate, and Cap and Battery Cell Using the Same

Publication Date: 2024.12.12 LG ENERGY SOLUTION LTD

AI summary

A battery cell includes a current collector plate having an axially extending can connecting part that is press-fit within a sidewall member having a multi-stage inner circumferential surface with different inner diameters. The battery cell is manufactured by inserting a cap into an open end of the can such that an axial inner surface of the cap contacts an axially outer end surface of the can connecting part and such that an outer circumferential surface of the cap contacts the inner circumferential surface of the sidewall member. Then a laser is irradiated in the axial direction on an area of the inner circumferential surface of the sidewall member and the outer circumferential surface of the cap in contact with one another, so as to form a triple welding portion.