Multi-Layer Bus Bar Module for Battery Cell Venting and Welding
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Solution Overview
Problem
Existing traction battery packs face challenges in reliably and efficiently connecting multiple battery cells to provide the necessary voltage and power for vehicle propulsion, particularly in ensuring secure electrical connections and effective venting and testing of battery cells.
Innovation Solution
A multi-layer bus bar module comprising a base layer, mid-layer, and top layer that retains and positions bus bars, integrates vent ports, and routes sense lead wiring, with features for secure welding access and finger-proofing to facilitate reliable electrical connections and monitoring of battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional array-to-array interconnects are used to connect battery cells, then electrical connections can be established, but the device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The bus bar module is divided into three distinct layers (base layer, mid-layer, top layer), each performing specific functions. The base layer provides structural support and first electrical connections, the mid-layer contains additional bus bars for expanded connectivity, and the top layer provides second electrical connections and protective coverage. This segmentation allows complex electrical interconnections to be achieved through modular, manageable layers rather than a single complex interconnect structure.
Solution Approach 2:
The patent transitions from traditional planar array-to-array interconnects to a three-dimensional multi-layer bus bar module structure. By stacking bus bars across multiple layers (base, mid, top) positioned at different Z-heights, the system achieves expanded electrical connectivity and routing capabilities that cannot be obtained with single-plane interconnects, while maintaining manufacturing feasibility through standardized layer assembly.
2Reliability
If welding access points are provided for bus bar connections, then reliable welding can be achieved, but the structural integrity and safety may be compromised
Solution Approach 1:
The top layer is segmented to include specific welding access points (first access points) that provide controlled openings for welding operations. These access points are strategically positioned to allow welding tool access to the second bus bars while maintaining the overall structural integrity of the top layer. The segmented design enables localized access without compromising the global structural strength of the bus bar module.
Solution Approach 2:
The top layer acts as an intermediary structure that mediates between the welding process requirements and the structural integrity requirements. By incorporating welding access points within the top layer design, the system allows welding operations to proceed while the top layer itself provides protective coverage and structural support around the access points, preventing direct exposure of the bus bars to environmental factors and mechanical damage.
3Reliability
If vent ports are integrated into the bus bar module, then battery cell venting can be monitored, but the manufacturing complexity increases
Solution Approach 1:
The vent port features are merged directly into the top layer structure of the bus bar module. The top layer includes integrated vent ports that align with vent systems of the battery cells, combining the protective coverage function with the vent monitoring function in a single integrated component. This merging eliminates the need for separate vent port assemblies and reduces the number of manufacturing steps and assembly operations required.
Solution Approach 2:
The top layer serves multiple functions simultaneously: it provides protective coverage for the bus bars, establishes second electrical connections through conductive paths, and incorporates vent ports for monitoring battery cell venting. By designing the top layer as a multi-functional component, the system achieves vent monitoring capability without adding separate dedicated venting structures, thereby maintaining manufacturing simplicity while enhancing system reliability.
Data Source
AI summary
Bus bar modules are provided for electrically connecting battery cells of a traction battery pack. An exemplary bus bar module may include a multi-layer assembly that includes a base layer, a mid-layer, and a top layer, with each layer having its own respective function(s). The bus bar module may provide the structure for both retaining bus bars and routing sense lead wiring. The bus bar module may further provide integrated features for venting, facilitating bus bar-to-terminal welding, and testing sense lead connections.