Prismatic Cell Forked Connector Welding
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Solution Overview
Problem
Conventional prismatic cell welding techniques are prone to failure due to deformation of the cantilever anvil under pressure, leading to potential welding defects and instability in the connection between the wound electrode body and collector members.
Innovation Solution
The prismatic cell design incorporates forked connector leaves on the collector members that contact and weld with separated laminates of the positive and negative electrode connection parts, ensuring stable connection surfaces and improved welding quality by distributing the metal foils into two laminates, which are then welded to the collector members, eliminating the need for a cantilever anvil and reducing connection resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cantilever anvil is used in ultrasonic welding of the current-collecting foil layered portion to the collector member, then welding connection is achieved, but the anvil deforms under pressure causing welding failure
Solution Approach 1:
The patent removes the cantilever anvil from the welding system entirely. Instead of using a separate anvil component that is prone to deformation, the welding is performed by directly pressing the chip against the collector member with the foil layered portion sandwiched between them. This extraction of the problematic anvil component eliminates the source of welding failure while maintaining the welding connection function.
2Ease of manufacture
If the laminate of positive and negative electrode sheets is kept intact during welding, then assembly is simpler, but welding quality deteriorates due to uneven pressure distribution
Solution Approach 1:
The patent segments the laminate structure by separating the positive and negative electrode sheets at the welding location. The innermost periphery part of each electrode sheet is pushed outward to create separated laminates, which allows the chip to apply pressure evenly to each layer individually. This segmentation improves welding quality by ensuring uniform pressure distribution and better contact between the foil layered portion and collector member, while the forked connector leaves provide a structured approach to maintaining assembly organization.
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 enhances the quality of the welded connections, stabilizes welding strength, and prevents defects such as stains, thereby improving the overall performance and reliability of the prismatic cell.
Implementation Method 1
the connection surfaces of the forked connector leaves of the positive and negative electrode collector members, respectively, are welded to the respective outer peripheral surfaces of the separated laminates
Data Source
AI summary
A wound electrode body is fabricated by laminating and winding positive and negative electrode sheets together with a separator therebetween for insulation. On both positive and negative electrode side ends of the wound electrode body, laminates of current-collecting foil layered portions of the electrode sheets are bent or folded f toward the outer peripheral side to be separated into two. The separated laminates and forked connector leaves are overlapped and clamped between an ultrasonic chip and an anvil. Then, they are welded. The forked connector leaves are arranged such that no opposing forked connector leaf is present in the direction of a line normal to the forked connector leaf, so that the anvil does not have to be cantilevered. This allows welding by using the ultrasonic chip and the anvil without interfering with the collector rs. As a result, the quality of welding is improved.