Negative Grid for Lead-Acid Battery
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Solution Overview
Problem
Conventional negative grids in lead-acid batteries, manufactured using the expanded metal process, often have exposed wire ends that can puncture the polymeric separator, leading to internal shorting and reduced battery life.
Innovation Solution
A method involving a progressive punching operation to form negative grids with a frame and interconnected wires, where the grid material is continuously cast and rolled, and then punched to create a grid shape without exposed ends, allowing for deformation and coating to enhance paste adhesion and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the expanded metal process is used to manufacture negative grids, then the grid structure can be formed efficiently, but exposed wire ends are created that can puncture the polymeric separator
Solution Approach 1:
The harmful exposed wire ends are removed from the grid structure by forming the grid in a recessed cavity. The punching operation creates a grid where all wire ends are contained within the recess, extracting the dangerous protruding ends from the system while maintaining the efficient punched grid structure.
Solution Approach 2:
The grid structure is nested within a recessed cavity in the battery plate. The grid wires are formed within this recessed space, and the frame members extend from the recess to provide structural support. This nesting contains the grid within a protective recess, preventing wire ends from protruding and puncturing the separator.
2Ease of manufacture
If conventional negative grids with exposed wire ends are used, then manufacturing is simpler, but internal shorting occurs reducing battery life
Solution Approach 1:
The harmful exposed wire ends that cause internal shorting are extracted from the grid structure by forming it within a recessed cavity. The punching operation creates a grid where all wire ends are contained within the recess, eliminating the shorting hazard while maintaining manufacturing efficiency.
Solution Approach 2:
The recessed cavity acts as a protective cushioning structure formed beforehand in the battery plate. This recess provides a protective space that contains the grid wires and prevents them from protruding and causing internal shorting, thereby protecting the battery from premature failure.
3Strength
If thicker grids are used to ensure structural integrity, then connection strength is maintained, but energy density decreases
Solution Approach 1:
The grid structure utilizes the third dimension by forming it within a recessed cavity rather than as a flat surface-mounted grid. This vertical dimension allows the grid to be thinner while maintaining structural integrity through the recess walls and frame members, thereby increasing energy density without sacrificing connection strength.
Data Source
AI summary
A method for producing a negative grid for a battery which includes providing a strip of battery grid material and performing a punching operation on the battery grid material to remove material and form a grid. The punching operation produces a negative battery grid having a plurality of grid wires bounded by a frame. The battery grid includes a top frame member. A first side frame member is coupled to the top frame member at a first end thereof. A second side frame member is coupled to the top frame member at a second end thereof. A bottom frame member is spaced apart from the top frame member and coupled to the first side frame member and the second side frame member. The negative grid does not include exposed wire ends that may puncture a polymeric separator when the negative grid is provided within the separator.