Superposed Composite Bus Bar for Battery Module Welding
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Solution Overview
Problem
The existing battery modules face challenges in improving the weldability and thermal and electrical characteristics of bus bars connecting battery cells, which affects the overall performance and reliability of the battery module.
Innovation Solution
A battery module design that incorporates a bus bar system with two superposed bus bars made of different metals, where the first bus bar is formed of the same material as the electrode terminals for improved weldability and the second bus bar, made of a higher conductivity material like copper, enhances thermal and electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-material bus bar is used, then the weldability to electrode terminals is improved, but the thermal and electrical characteristics are insufficient
Solution Approach 1:
The bus bar is constructed as a composite structure with a first bus bar made of aluminum or aluminum alloy (matching electrode terminal material for weldability) and a second bus bar made of copper or copper alloy (for superior thermal and electrical characteristics). The two materials are superposed and bonded together, combining the advantages of both materials to resolve the contradiction between weldability and electrical/thermal performance.
Solution Approach 2:
The bus bar is divided into two distinct segments (first bus bar and second bus bar) made of different materials, each performing its specialized function. The aluminum segment handles welding to terminals while the copper segment handles current conduction, allowing optimization of each segment for its specific purpose.
2Reliability
If a copper bus bar is used, then the thermal and electrical characteristics are improved, but the weldability to aluminum electrode terminals deteriorates
Solution Approach 1:
The composite bus bar structure places the copper second bus bar in direct contact with the aluminum first bus bar, which is welded to the aluminum electrode terminals. This configuration allows the copper to provide excellent electrical and thermal conductivity without requiring direct welding to the terminals, thus resolving the weldability issue while maintaining superior electrical performance.
3Device complexity
If a single-material bus bar is used, then the structure is simple, but the ohmic loss is high and electrical output power performance is reduced
Solution Approach 1:
The copper-containing composite bus bar structure reduces ohmic loss by utilizing copper's superior electrical conductivity in the current conduction path. Although the structure is more complex than a single-material bus bar, the significant reduction in energy loss justifies the added complexity, achieving better overall electrical efficiency.
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 improves the weldability and thermal and electrical characteristics of the bus bar, reducing ohmic loss and increasing electrical output power performance while ensuring secure coupling between the bus bar and electrode terminals.
Implementation Method 1
a bus bar connected to the electrode terminals of the battery cells neighboring each other to electrically connect the battery cells, the bus bar including a first bus bar and a second bus bar that are superposed on each other and include different metals
Implementation Method 2
improve the thermal and electrical characteristics of a bus bar while improving the weldability of the bus bar
Data Source
AI summary
Provided is a battery module. The battery module includes: a plurality of battery cells each including an electrode terminal; and a bus bar connected to the electrode terminals of the battery cells neighboring each other to electrically connect the battery cells, the bus bar including a first bus bar and a second bus bar that are superposed on each other and include different metals, each of the first and second bus bars making conductive contact with the electrode terminals. Therefore, the thermal and electrical characteristics of the bus bar electrically connecting the neighboring battery cells to each other may be improved while improving weldability between the bus bar and electrode terminals.