Lead Plate Fixation in Secondary Battery Cap Assembly
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Solution Overview
Problem
Conventional secondary batteries face issues with the fixation of the lead plate to the cap plate and exposure of connection terminals during hot-melt molding due to protruding sealing and welding parts, leading to unreliable connections and production quality.
Innovation Solution
The lead plate is integrated with a bottom plate and side walls, and a straight linear connection terminal is used, which is welded to the lead plate, ensuring firm fixation and preventing exposure during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing unit and welding part protrude above the cap plate to seal the electrolyte injection hole, then the sealing reliability is improved, but the lead plate cannot be firmly welded to the cap plate because the lower ends of the side walls cross the protruding parts
Solution Approach 1:
The lead plate is designed with side walls that extend in the vertical dimension to overlap the protruding sealing unit and welding part, changing from a two-dimensional placement to a three-dimensional overlapping structure. This allows the lead plate to be firmly welded to the cap plate while the sealing unit maintains its protruding position for reliable sealing.
Solution Approach 2:
The lead plate structure is designed to contain or overlap the protruding sealing unit and welding part within its side wall structure. The side walls of the lead plate extend vertically to encompass the protruding parts, creating a nested configuration where the sealing components are positioned within the spatial envelope of the lead plate structure.
2Adaptability or versatility
If the connection terminal is L-shaped to connect the protective circuit unit to the lead plate, then the connection flexibility is improved, but part of the connection terminal is not welded to the lead plate and may protrude or deform during hot-melt molding
Solution Approach 1:
The unnecessary L-shaped protruding portion is removed from the connection terminal design. Instead of using an L-shape that requires bending and creates exposed portions, the connection terminal is designed as a straight linear structure that is fully welded to the lead plate, extracting the problematic geometric feature while maintaining the electrical connection function.
Solution Approach 2:
Instead of designing the connection terminal to bend at an angle (L-shape) to accommodate the connection, the invention inverts the approach by using a straight linear connection terminal that extends perpendicularly from the lead plate surface. This inverted geometry eliminates the bending requirement and ensures complete welding coverage.
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 solution enhances the fixation of the lead plate to the cap plate and prevents connection terminal exposure, improving the reliability and mass production quality of the battery.
Implementation Method 1
The connection terminal may be obtained by bending a square flat plate so that one surface is welded to one side wall of the lead plate
Data Source
AI summary
In the secondary battery, a lead plate is provided so as not to overlap the position of the sealing unit of the electrolyte injection hole to enhance the fixation of the lead plate to the upper surface of the cap plate of a cap assembly. The position of a connection terminal of a protective circuit unit corresponds to the position of the lead plate and together with the connection terminal shape the connection terminal is prevented from being exposed to the outside during hot-melt molding.