Pouch Cell Contact Tab Structure for Safer Stack Assembly
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Solution Overview
Problem
Pouch cells in battery packs for electric hand tools face challenges in mass production due to difficult handling and potential short-circuiting, and they cannot be resistance welded for electrical contacting, leading to high technical and financial efforts in automated systems.
Innovation Solution
The introduction of upper and lower connecting elements on both plus and minus contact tabs allows for easy and secure electrical contacting, enabling the creation of stacks with pouch cells that can be connected via plug-in, screwing, or heating, reducing thermal shutdowns and increasing operational time or power capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pouch cells are used with conventional contact tab design, then the battery pack can be assembled, but the handling difficulty increases and short-circuit risk increases during mass production
Solution Approach 1:
The contact lug is segmented into upper and lower connecting elements that are spatially separated. This segmentation allows the connecting elements to be positioned away from each other, preventing simultaneous contact with opposite polarity tabs and eliminating short-circuit risk during handling and assembly operations.
Solution Approach 2:
The patent introduces an intermediate structural design where the connecting elements are extended and positioned to require deliberate assembly actions for contact. This intermediate configuration acts as a mediator that prevents accidental short-circuits while maintaining electrical connectivity functionality.
2Device complexity
If pouch cells are used without resistance-weldable contact tabs, then the cell design is simplified, but the automated contacting system complexity and cost increase
Solution Approach 1:
The connecting elements are designed with multi-functionality, serving both as electrical contacts and as mechanical connection features. By making the connecting elements universal (capable of both electrical and mechanical functions), the patent eliminates the need for specialized resistance-welding equipment while maintaining automated assembly capability through plug-in or screw connections.
Solution Approach 2:
The patent replaces the conventional resistance-welding mechanical system with alternative connection methods such as plug-in connections or screw connections. This substitution eliminates the need for complex welding equipment and processes while achieving reliable electrical and mechanical connection of pouch cells in automated manufacturing.
3Duration of action of moving object
If cylindrical lithium-ion cells are used in battery packs, then the battery pack can be assembled, but thermal shutdown occurs earlier due to higher power losses
Solution Approach 1:
The patent changes the electrical resistance parameter by using pouch cells with optimized internal structure and connecting elements that provide lower contact resistance. This parameter change reduces power losses (I²R losses) during operation, allowing the battery pack to operate longer before thermal shutdown occurs or to deliver higher power levels sustainably.
Data Source
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AI summary
The invention relates to a pouch cell comprising a positive contact tab and a negative contact tab, by means of which tabs the pouch cell can be electrically contacted and thus charged and discharged. The pouch cell is planar and has a flat cell surface which extends in parallel with the positive contact tab and the negative contact tab. The positive contact tab comprises an upper positive connection element and a lower positive connection element, which are arranged on opposite sides of the positive contact tab, and the negative contact tab comprises an upper negative connection element and a lower negative connection element, which are arranged on opposite sides of the negative contact tab.