Battery Pack Restricting Member for Electrode Tab Alignment

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Solution Overview

Problem

In conventional battery packs, the variability in unit cell thickness leads to misalignment of electrode tab ends with bus bar recesses, resulting in insufficient electrical conductivity due to inadequate contact between the bus bar and electrode tabs.

Innovation Solution

A battery pack design that includes a restricting member between electrode tabs to maintain precise alignment, ensuring the bus bar and electrode tabs are securely connected, even when unit cell positions shift during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrode tab position is not restricted, then the assembly process is simple, but the electrical conductivity between bus bar and electrode tab becomes insufficient due to misalignment

Engineering Contradiction:
Improveelectrical conductivityVSAvoidalignment restriction structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a restricting member as an intermediary component between the electrode tab and the bus bar. This restricting member has a recessed portion that receives the electrode tab, thereby restricting its position in the stacking direction and ensuring proper alignment with the bus bar for reliable electrical conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The restricting member is designed to automatically align the electrode tab with the bus bar through its recessed portion geometry. The electrode tab is inserted into the recessed portion, which self-adjusts to the correct position, eliminating the need for complex external alignment mechanisms.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If the bus bar and electrode tab are joined without position restriction, then the manufacturing process is simpler, but the joining quality deteriorates due to insufficient contact

Engineering Contradiction:
Improvejoining qualityVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The restricting member is pre-formed with a recessed portion that is designed to receive the electrode tab at the correct position. This preliminary preparation of the restricting member ensures that when assembly occurs, the electrode tab is already positioned correctly for high-quality joining with the bus bar.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the electrode tabs are allowed to shift during use, then the structure is more flexible, but the contact integrity between bus bar and electrode tab is compromised

Engineering Contradiction:
Improvecontact integrityVSAvoidposition flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The restricting member provides localized position restriction only at the critical joining area where the electrode tab contacts the bus bar. The recessed portion of the restricting member confines the electrode tab position specifically in the stacking direction at the joint portion, while allowing flexibility in other areas of the battery pack structure.

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 design enhances the electrical conductivity between bus bars and electrode tabs, improving the joining quality and maintaining contact integrity despite potential shifts in unit cell positions, thereby ensuring reliable electrical connections.

Implementation Method 1

a restricting member that is disposed between portions of the electrode tabs that are adjacent in the stacking direction, and that extend along the stacking direction and restricts a stacking direction positions of the portions of the electrode tabs that extend along the stacking direction by sandwiching the electrode tabs with the spacer

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a bus bar holder that holds the bus bars

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

The of the electrode tabs that extend along the stacking direction are welded to a surface of the bus bars facing the unit cells

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3367469B1Assembled battery
Publication Date: 2020.02.12 ENVISION AESC JAPAN LTD
  • EP3367469B1 patent drawingFigure 1
  • EP3367469B1 patent drawingFigure 2
  • EP3367469B1 patent drawingFigure 3~4

AI summary

[PROBLEM] To provide a battery pack in which sufficient conduction can be obtained between a bus bar and the electrode tab of each unit cell. [SOLUTION] The battery pack 100 comprises a cell group and a bus bar 131. The cell group includes a plurality of unit cells stacked in a thickness direction with a cell body, which includes a power generation element and has a flat shape, and an electrode tab 113 protruding out from the cell body, and the distal end portions 113d of the electrode tabs are bent along the stacking direction Z of the unit cells. The bus bar is shaped in a flat plate shape and joined to the distal end portions of the electrode tabs of the unit cells while facing the distal end portions, and electrically connects the electrode tabs of at least two of the unit cells to each other. The battery pack 100 further has a restricting member 135 that is disposed between electrode tabs that are adjacent to each other in the stacking direction of the unit cells, and that restricts the positions of the distal end portions of the electrode tabs in the stacking direction.