Battery Module Bus Bar Layout Without Dissimilar Metal Welding
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Solution Overview
Problem
The challenge in battery module design is to connect multiple battery groups in series without using clad materials, which would otherwise require dissimilar metal welding, complicating the production process and increasing costs.
Innovation Solution
The solution involves using bus bars made of similar metals, such as aluminum and copper, to connect battery cells within each group in parallel, and then using mechanical joint portions to connect these bus bars between adjacent battery groups in series, thereby avoiding the need for clad materials and dissimilar metal welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clad materials are used for bus bars to connect battery groups in series, then dissimilar metal welding can be avoided, but production complexity and cost increase
Solution Approach 1:
The bus bar system is segmented into multiple components: a first bus bar made of aluminum-based metal for parallel connection, a second bus bar made of copper-based metal for parallel connection, and a connecting portion for series connection between battery groups. This segmentation allows each component to be optimized for its specific function and material requirements, avoiding the need for complex clad structures.
Solution Approach 2:
A connecting portion acts as an intermediary element between the aluminum-based first bus bar and the copper-based second bus bar. This intermediary enables series connection between battery groups while allowing the use of dissimilar metals (aluminum and copper) in the bus bar system, thereby avoiding the need for clad materials and dissimilar metal welding.
2Reliability
If dissimilar metal welding is used to connect aluminum and copper bus bars, then connection reliability improves, but manufacturing difficulty and cost increase
Solution Approach 1:
The connecting portion serves as an intermediary that physically and electrically connects the aluminum-based first bus bar and the copper-based second bus bar without requiring dissimilar metal welding. This intermediary approach maintains connection reliability while avoiding the manufacturing difficulties of welding dissimilar metals.
Solution Approach 2:
The invention replaces the welding process (thermal/chemical joining method) with a mechanical connection method using the connecting portion. This substitution eliminates the need for dissimilar metal welding while maintaining reliable electrical and mechanical connection between bus bars of different materials.
3Adaptability or versatility
If longer bus bars are used to connect all battery cells in series, then series connection capability improves, but production cost and material usage increase
Solution Approach 1:
The bus bar system is divided into separate first and second bus bars with a connecting portion, allowing each segment to be optimized in length and material usage. This segmentation enables series connection capability while reducing overall material consumption compared to using single long clad bus bars.
Solution Approach 2:
The invention changes the material parameter of the bus bar system by using dissimilar metals (aluminum and copper) in separate bus bars rather than a single clad material. This parameter change enables series connection capability while optimizing material usage and reducing production costs.
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 allows for efficient connection of battery groups in series while maintaining high productivity and reducing production costs associated with using clad materials, while also ensuring reliable electrical connections and increased connection reliability due to the use of similar metals and mechanical joints.
Implementation Method 1
The first bus bar mainly containing aluminum is connected to the positive electrode terminals of the plurality of battery cells of each battery group via welding joint portions, the second bus bar mainly containing copper and is connected to the negative electrode terminals of the plurality of battery cells of each battery group via welding joint portions
Data Source
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AI summary
An object of the present disclosure is to provide a battery module including a plurality of battery groups each having a plurality of battery cells connected in parallel, the plurality of battery groups being connected in series by bus bars, for which a clad material is not used and thus dissimilar metal welding can be avoided. To achieve the object, a first bus bar 20P mainly contains aluminum and is connected to positive electrode terminals of a plurality of battery cells 1 of each battery group 10 via welding joint portions W1. A second bus bar 20N mainly contains copper and is connected to negative electrode terminals of the plurality of battery cells 1 of each battery group 10 via welding joint portions W2. The first bus bar 20P of one of the mutually adjacent battery groups 10 of the plurality of battery groups 10 is connected to the second bus bar 20N of the other battery group 10 via a mechanical joint portion M.