Bowed Busbar Design for Battery Cell Height Variations
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Solution Overview
Problem
Existing busbars in vehicle traction battery assemblies face challenges due to height differences between adjacent cells, leading to inadequate contact and potential welding issues, as they are typically made of rigid materials that do not accommodate varying cell dimensions effectively, resulting in either small contact interfaces or increased stress and deformation.
Innovation Solution
A busbar design featuring a pair of bowed sections joined at a midpoint, allowing for increased contact area and self-adjustment to accommodate different terminal heights, which pivots to maintain a stable interface and facilitate welding, reducing stress and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid busbar is used to connect battery terminals, then the structural strength is maintained, but the contact area is reduced when terminals are at different heights
Solution Approach 1:
The busbar incorporates a bowed section with a neutral axis that allows the busbar to flex and adapt to height differences between terminals. This dynamic capability enables the busbar to maintain adequate contact area while accommodating varying terminal positions, resolving the contradiction between structural rigidity and contact area maintenance.
Solution Approach 2:
The busbar design changes the geometric parameter of the connection interface by introducing a bowed section with a neutral axis. This parameter change allows the busbar to pivot and adjust its contact point, maintaining sufficient contact area even when terminals are at different heights, thus resolving the contradiction between strength and contact area.
2Ease of manufacture
If a rigid busbar is used to connect battery terminals, then the manufacturing simplicity is maintained, but the welding reliability is reduced due to inadequate contact
Solution Approach 1:
The bowed section with neutral axis provides a pivot point that allows the busbar to self-adjust during installation and welding. This dynamic adjustment ensures adequate contact between the busbar and terminals at different heights, improving welding reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The busbar's bowed section with neutral axis enables self-adjustment to accommodate height variations between terminals. This self-service capability ensures proper contact and welding conditions are achieved automatically during installation, improving welding reliability while maintaining manufacturing simplicity.
3Area of stationary object
If the busbar is made to accommodate height differences, then the contact area is increased, but the device complexity increases
Solution Approach 1:
Instead of using complex adjustable mechanisms or multiple components, the invention employs a simple bowed section with a neutral axis that provides the necessary adaptability. This elegant solution increases contact area while minimizing device complexity by using a single integrated structural feature.
4Stability of the object's composition
If the busbar pivots to accommodate terminal height differences, then the contact interface stability is improved, but the stress distribution on the busbar changes
Solution Approach 1:
The introduction of a neutral axis in the bowed section changes the stress distribution parameters of the busbar. The neutral axis serves as a pivot point that allows controlled rotation and adjustment, stabilizing the contact interface while managing stress distribution through the geometric design of the bowed section.
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 bowed section design enhances the contact area and weldable range between the busbar and terminals, improving the reliability and durability of connections while minimizing production costs and stress on the busbar, thus addressing the challenges of varying cell heights and manufacturing imperfections.
Implementation Method 1
The busbar has a longitudinal midpoint and defines a pair of bowed sections joined at the midpoint. An arcuate portion along each of the bowed sections is in contact with one of the terminals when the terminals are at different elevations relative to a battery tray to provide increased contact between the busbar and terminals.
Data Source
AI summary
A traction battery assembly includes adjacent battery cells supported by a tray and a busbar electrically connecting the adjacent battery cells. The busbar includes a longitudinal midpoint and a pair of bowed sections joined at the midpoint. Each of the bowed sections has an actuate portion in contact with a terminal on one of the cells. The bowed sections provide increased contact with the cells when the cells have different elevations with respect to the tray. A busbar module is also disclosed. The busbar module comprises a housing and a busbar supported within the housing.