Flexible Arced Busbar for Battery Module Stress Management

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Solution Overview

Problem

Conventional busbars for battery modules are often rigid and contribute to the overall height of the module, limiting their compactness and flexibility, and fail to effectively manage mechanical stress and cell expansion/contraction.

Innovation Solution

A low-height, flexible busbar design featuring arced portions that act as expansion joints, allowing relative movement between contact portions and decoupling mechanical properties from module height, while maintaining electrical connectivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional rigid busbars are used for battery module construction, then structural stability is improved, but device height increases and flexibility is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoiddevice height
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The busbar design transitions from a conventional planar structure to a three-dimensional configuration with arced portions extending in a second plane perpendicular to the contact portions. This dimensional change allows the busbar to achieve structural stability through spatial distribution while maintaining a low profile in the height direction, effectively resolving the contradiction between stability and height.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The busbar incorporates flexible arced portions that can dynamically deform to accommodate cell expansion and contraction during battery operation. This dynamic capability allows the busbar to maintain structural integrity and electrical connectivity while adapting to dimensional changes, thereby providing stability without requiring excessive height.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If simple bar-shaped aluminum strips are used for busbars, then manufacturing complexity is reduced, but adaptability to cell expansion/contraction is worsened

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidadaptability to cell expansion/contraction
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The busbar is segmented into distinct functional portions: contact portions for electrical connection and arced portions for mechanical flexibility. This segmentation allows each portion to be optimized for its specific function while maintaining overall manufacturability through conventional forming processes, balancing ease of manufacture with adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The busbar design changes the geometric parameters of the arced portions, specifically the arc radius and segment length, to optimize the balance between flexibility and manufacturability. These parameter adjustments enable the busbar to accommodate cell dimensional changes while remaining compatible with standard manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If complex three-dimensional busbar shapes are used, then flexibility and compactness are improved, but device height increases

Engineering Contradiction:
ImproveflexibilityVSAvoiddevice height
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The arced portions extend in a second plane that is essentially perpendicular to the plane of the contact portions, utilizing the vertical dimension for flexibility while keeping the height dimension (third direction) minimal. This strategic use of dimensional space allows the busbar to achieve compactness and flexibility without increasing overall module height.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Stability of the object's composition

If rigid busbars are used, then electrical connectivity stability is improved, but mechanical stress management is worsened

Engineering Contradiction:
Improveelectrical connectivity stabilityVSAvoidmechanical stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The arced portions are designed with controlled flexibility to dynamically deform and absorb mechanical stress from cell expansion and contraction. This dynamic response protects the rigid contact portions and welding points from excessive stress while maintaining stable electrical connectivity, effectively decoupling stress management from connectivity stability.

Inventive Principle:
Principle #15Dynamics

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 flexible busbar design reduces mechanical stress, accommodates cell expansion/contraction, and maintains module compactness by allowing deformation without increasing height, enhancing the stability and efficiency of battery modules.

Implementation Method 1

the arced portion is configured for allowing a relative movement of the first contact portion and the second contact portion, e.g., provided by a deformation of the arced portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the plasticity of the arced portion is preferably such that a relative movement of the first and the second contact portion occurs in response to a mechanical load applied thereto

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3654410B1Busbar for a battery module and battery module
Publication Date: 2022.08.10 SAMSUNG SDI CO LTD
  • EP3654410B1 patent drawingFigure 1~2
  • EP3654410B1 patent drawingFigure 3~5
  • EP3654410B1 patent drawingFigure 6~7

AI summary

The present invention is directed to a busbar (50) for connecting cell terminals (11, 12) of at least two battery cells (10) of a battery module (90), the busbar (50) comprising a first contact portion (21) configured to connect to a first cell terminal (11), a second contact portion (22) configured to connect to a second cell terminal (12), and an arced portion (30) configured to connect the first contact portion (21) and the second contact portion (22). The contact portions (21, 22) extend in a first plane and the arced portion (30) extend in a second plane essentially perpendicular to the first plane. Further, a first bent portion (41) extends from the first contact portion (21) into the second plane and connects the first contact portion (21) and the arced portion (30) and a second bent portion (42) extends from the second contact portion (22) in the second plane and connects the second contact portion (22) and the arced portion (30). The invention also relates to a battery module (90) with a plurality of battery cells (10) aligned in a lengthwise direction of the battery module (90) and a plurality of busbars (50) according to the invention for electrically interconnecting at least two battery cells (10) of the module (90). Therein, at least one first contact portion (21) of each busbar (50) is electrically connected to a cell terminal (11) of a first polarity and at least one second contact portion (22) of each busbar (50) is electrically connected to a cell terminal of a second polarity (12).