Traction Battery Pack Assembly Using Low-Voltage Cell Subassemblies
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Solution Overview
Problem
Existing methods for assembling traction battery packs face challenges in efficiently connecting battery cells to form high-voltage stacks while ensuring safe handling and transportation of low-voltage subassemblies, as they require complex electrical connections and risk electrical discharges during assembly and movement.
Innovation Solution
A method involving the positioning of battery cells with tab terminals, where the terminals are connected on one side and disconnected on the opposite side, allowing for insertion through apertures in cross-members, and subsequent welding to form electrical connections, enabling the assembly of low-voltage subassemblies that can be safely combined to create high-voltage stacks within an enclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery cells are connected to form high-voltage stacks during assembly, then the battery pack can be assembled, but electrical discharges and safety risks occur during handling and transportation
Solution Approach 1:
The battery pack assembly is divided into modular subassemblies, each containing a subset of battery cells connected in series to form low-voltage configurations (e.g., 12V, 24V, 48V). These modular units can be handled and transported independently with reduced electrical risk, then later integrated into the complete high-voltage battery pack within the enclosure.
Solution Approach 2:
Battery cells are pre-connected in low-voltage configurations and allowed to rest in a charged state before final assembly. This preliminary connection and resting period enables safe handling and transportation of subassemblies without the electrical discharge risks associated with complete high-voltage stack assembly.
2Productivity
If complex electrical connections are made during assembly, then high-voltage stacks are formed, but the assembly process becomes more complex and time-consuming
Solution Approach 1:
The complete battery pack is segmented into multiple subassemblies that can be manufactured and prepared independently. This segmentation allows parallel processing of multiple units, reducing overall assembly time while maintaining connection integrity through standardized interfaces.
Solution Approach 2:
Electrical connections are established in advance during subassembly fabrication rather than during final battery pack assembly. This preliminary action transfers connection complexity to a controlled manufacturing environment, enabling more efficient final assembly operations.
3Power
If battery cells are arranged in series to increase voltage, then higher voltage is achieved, but the risk of electrical discharge increases during assembly and movement
Solution Approach 1:
The high-voltage battery pack is divided into multiple low-voltage subassemblies connected in series. Each subassembly operates at a safer voltage level during handling and transportation, reducing electrical discharge risk. The high-voltage configuration is only achieved when all subassemblies are properly integrated within the final enclosure.
Solution Approach 2:
Battery cells are connected in series to achieve desired voltage levels during controlled manufacturing processes where safety measures are in place, then allowed to rest in a charged state. This preliminary high-voltage configuration is maintained only during controlled conditions, not during general handling or transportation.
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 method allows for the safe and efficient assembly of high-voltage traction battery packs by maintaining low-voltage connections during handling and transportation, reducing the risk of electrical discharges and simplifying the assembly process, while ensuring reliable electrical connections within the enclosure.
Implementation Method 1
subsequent welding to form electrical connections
Data Source
AI summary
A method of assembling a battery pack, includes positioning at least one first battery cell having tab terminals adjacent to at least one second battery cell having tab terminals to provide a battery cell subassembly. The tab terminals of the at least one first battery cell and the at least one second battery cell are connected on a first side of the battery cell subassembly. The tab terminals of the at least one first battery cell and the at least one second battery cell are disconnected on an opposite, second side of the battery cell subassembly. After he positioning, the method includes inserting the tab terminals that are disconnected through at least one aperture in a cross-member.