Cylindrical Battery Sealing With Conductive Elastomer and Double Seaming
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Solution Overview
Problem
Conventional cylindrical batteries face challenges such as complex assembly processes, high manufacturing costs, and poor anti-rust capabilities due to nickel-plated steel cases and laser penetration welding, which affect the service life and reliability of the battery.
Innovation Solution
A cylindrical battery design featuring a conductive elastomer and thermosetting conductive adhesives for connecting the negative sheet tab to the case, a double-seaming process for sealing, and a reduced number of mechanical parts and laser welding processes, along with a variable-pitch variable-height tab structure for the positive sheet tab and an equal-pitch equal-height multi-tab structure for the negative sheet tab, to simplify assembly and enhance sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser penetration welding is performed on the nickel-plated steel case, then the current collector can be connected to the case, but the nickel texture is damaged and anti-rust capability deteriorates
Solution Approach 1:
The patent replaces laser penetration welding with a mechanical expansion and deformation mechanism. The sealing edge of the case opening is expanded outward to form a flange, which is then deformed to press against the cap assembly, creating a mechanical seal and connection that avoids laser welding damage to the nickel plating
Solution Approach 2:
The patent changes the geometric parameters of the case opening by expanding the sealing edge outward to form a flange with a larger diameter than the case body. This parameter change enables a new connection mechanism that avoids the harmful effects of laser welding while maintaining connection strength
2Ease of manufacture
If the roll core is fastened only through the rear lower edge of the roll groove, then the assembly process is simple, but the fastening becomes unreliable with increased battery cell diameter
Solution Approach 1:
The patent adds a new dimensional constraint by introducing a groove at the front end of the roll core that engages with a corresponding protrusion on the cap assembly. This front-end constraint complements the existing rear-end fastening, preventing axial movement in both directions and improving reliability without significantly complicating the assembly process
3Reliability
If conventional sealing methods (roll groove or laser welding) are used, then the battery can be sealed, but laser sealing is low in efficiency and high in cost
Solution Approach 1:
The patent replaces laser welding sealing with a mechanical expansion and deformation mechanism. The sealing edge is expanded to form a flange that is then deformed to press against the cap assembly, creating a reliable mechanical seal that is more efficient and cost-effective than laser welding
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 simplifies the assembly process, reduces production costs, and improves the sealing effectiveness and service life of the battery by using conductive elastomers and thermosetting adhesives, while maintaining high efficiency and reliability.
Implementation Method 1
a lower portion of the roll core is fixedly connected to the case via the conductive elastomer
Implementation Method 2
thermosetting conductive adhesive layers are arranged on two sides of the conductive elastomer
Implementation Method 3
an upper portion of the cap assembly is sealed via the liquid injection sealing pin
Implementation Method 4
the flange and the cap assembly that are double-seamed
Data Source
AI summary
A cylindrical battery includes a case, and a conductive elastomer, a roll core, a current collector, an insulating element, a cap assembly, and a liquid injection sealing pin sequentially arranged inside the case from bottom to top; a lower portion of the roll core is fixedly connected to the case via the conductive elastomer, an upper portion of the roll core is welded with the current collector, an upper portion of the current collector passes through the insulating element and is welded with the cap assembly, the insulating element is configured to prevent the cap assembly and the roll core from being short-circuited, and an upper portion of the cap assembly is sealed via the liquid injection sealing pin; and a necking and a flange are defined on an outside of the case, a conductive adhesive layer is arranged on an outside of the flange.