Two-Stage Plunger Press for Battery Cell Tab Bending
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Solution Overview
Problem
Current metalworking techniques for bending battery cell tabs in automotive applications face challenges in accommodating mixed material and thickness variations, leading to inefficiencies in terminal engagement and potential strain on battery modules.
Innovation Solution
A two-stage plunger press system with adjustable plungers and die cavities is employed to bend battery cell tabs to a precise angle, accommodating variations in thickness and material, ensuring flush engagement with busbar plates while minimizing strain on the battery module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current metalworking techniques are used to bend battery cell tabs, then the bending process can be completed, but the process cannot accommodate mixed material and thickness variations, leading to inefficiencies and potential strain on battery modules
Solution Approach 1:
The press system employs a two-stage plunger mechanism where the first plunger performs an initial bend and the second plunger completes the final bend to precise angles. This dynamic, multi-stage approach allows the system to adapt to varying tab thicknesses and materials (aluminum, copper, or composites) while maintaining consistent engagement with busbar plates, thereby preventing strain on battery modules.
Solution Approach 2:
The die cavities are configured with specific geometric features including radiused corners and varying depths to accommodate different tab materials and thicknesses. The first and second plungers apply force at different stages and locations, with the second plunger providing precise angular positioning. This localized differentiation in the forming process enables the system to handle mixed material variations while ensuring reliable terminal engagement without excessive strain on the battery module.
2Adaptability or versatility
If larger busbar plates are used to accommodate tab variations, then all tab types can engage, but the number and size of busbar plates increase, leading to higher costs
Solution Approach 1:
The two-stage plunger press system dynamically adjusts the bending process through sequential action. The first plunger creates an initial bend that positions tabs with varying thicknesses and materials, then the second plunger completes the form to the precise angle required for engagement. This dynamic forming capability allows standard-sized busbar plates to accommodate all tab variations, eliminating the need to increase busbar plate quantity or size.
Solution Approach 2:
The die cavities incorporate parameter variations including radiused corners, varying cavity depths, and specific geometric configurations that enable the same busbar plate design to accommodate different tab materials and thicknesses. By changing the forming parameters in the two-stage process rather than the busbar plate dimensions, the system achieves universal compatibility without increasing component size or quantity.
3Device complexity
If a single-stage press is used to bend tabs, then the process is simpler, but it cannot achieve precise bend angles for flush engagement, leading to poor terminal-to-busbar engagement
Solution Approach 1:
The bending process is segmented into two distinct stages performed by separate plungers. The first plunger executes an initial bend to a predetermined angle, and the second plunger completes the bend to the final precise angle required for flush engagement. This segmentation of the forming process enables manufacturing precision that cannot be achieved with a single-stage press, while the modular plunger design keeps the overall device complexity manageable.
Solution Approach 2:
The first plunger performs a preliminary bend that positions the tab at an intermediate angle, preparing it for the final precise bend by the second plunger. This preliminary action allows the second plunger to focus on achieving the exact bend angle required for flush engagement with the busbar plate, thereby achieving high manufacturing precision through coordinated multi-stage action.
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 solution reduces the number and size of busbar plates, achieves efficient terminal-to-busbar engagement, and minimizes strain on the battery module, resulting in cost savings and improved manufacturing efficiency.
Implementation Method 1
A two-stage plunger press system with adjustable plungers and die cavities is employed to bend battery cell tabs to a precise angle
Data Source
AI summary
Presented are metalworking systems for forming metallic workpieces, methods for making/operating such systems, and battery packs with cell terminals bent by a two-stage plunger press. A metalworking system includes a first plunger with a plunger cavity extending through the first plunger's body, and one or more die cavities recessed into the first plunger's contact face. The die cavity includes one surface that contacts and bends a first workpiece a first angle, and another surface that contacts and bends a second workpiece a second angle. A second plunger includes one or more die cavities recessed into the second plunger's contact face. This die cavity includes one surface that contacts and bends the first workpiece a third angle, and another surface that contacts and bends the second workpiece a fourth angle. The second plunger passes through the plunger cavity such that the first and second plungers bend the metallic workpieces in tandem.