Secondary Battery Current Collector Joint Design

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Solution Overview

Problem

Existing prismatic secondary batteries face challenges in achieving high reliability and increased volume energy density due to limitations in the current collector members that connect terminals and tabs, leading to potential gaps and defects in the joint connections.

Innovation Solution

A secondary battery design utilizing a first current collector and a second current collector with a high-reliability joint, where the second current collector is disposed on the first current collector and welded around an opening, enhancing the electrical connection between the terminal and tab, and including an insulating member to prevent defects, thereby increasing energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a current collector member is formed of a single component, then the structure is simple, but the volume energy density cannot be increased

Engineering Contradiction:

Improvecurrent collector structureVSAvoidvolume energy density

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The current collector member is divided into a first current collector and a second current collector. The first current collector connects the terminal to the electrode sheet, while the second current collector connects the tab to the electrode sheet. This segmentation allows for optimized spatial arrangement and reduced material usage, thereby increasing volume energy density while maintaining structural functionality.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If a current collector member is formed of plural components, then the volume energy density can be increased, but the reliability of the joint between components is reduced

Engineering Contradiction:

Improvevolume energy densityVSAvoidjoint reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The first current collector and the second current collector are joined through welding to form an integrated current collector member. This merging of components ensures strong electrical and mechanical connection reliability, eliminating the risks associated with multiple separate components while maintaining the volume energy density benefits of the multi-component design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The current collector member is constructed as a composite structure combining the first current collector and second current collector through welding. This composite approach allows optimization of each component's function while ensuring reliable integration, achieving both high volume energy density and joint reliability.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the second current collector is welded to the first current collector around the opening, then the joint reliability is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvejoint reliabilityVSAvoidcurrent collector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The first current collector and second current collector are designed with predetermined shapes and opening positions before assembly. The opening in the second current collector is positioned to align with the first current collector, allowing for straightforward welding around the opening without requiring complex positioning or adjustment during manufacturing.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If the opening in the second current collector is used for welding, then the joint reliability is improved, but the detection of gaps becomes more difficult

Engineering Contradiction:

Improvejoint reliabilityVSAvoidgap detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The opening in the second current collector serves as a visual indicator for gap detection. By observing the opening, inspectors can easily determine whether gaps exist between the first and second current collectors during welding, transforming a potential weakness into a detection advantage without compromising joint reliability.

Inventive Principle:

Principle #32Color 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

The proposed design achieves a high-reliability joint between the current collectors, resulting in a secondary battery with increased volume energy density and improved manufacturing efficiency.

Implementation Method 1

The second current collector is disposed on the first current collector and welded to the first current collector around the opening

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS11509025B2Secondary battery and method of manufacturing the same

Publication Date: 2022.11.22 SANYO ELECTRIC CO LTD

AI summary

A negative-electrode terminal that is secured to a sealing plate is connected to a first negative-electrode current collector. A negative-electrode tab that is connected to the negative-electrode sheet is connected to a second negative-electrode current collector. The first negative-electrode current collector and the second negative-electrode current collector are disposed along the sealing plate. The second negative-electrode current collector has an opening. The second negative-electrode current collector is disposed on the first negative-electrode current collector such that the opening faces the first negative-electrode current collector. The second negative-electrode current collector is welded to the first negative-electrode current collector around the opening.