Quick film removing and firm tin soldering grouping method for soft-packed lithium battery with low resistance, low heat and large over-current

Abstract

The invention can realize tin soldering grouping of a soft-packed power ternary lithium battery. Firstly, the positive aluminum electrode of one battery and an adapter sheet (to nickel) or the negative plate of another battery (series connection) are pre-tightened and bonded by traditional spot welding, hot pressing (simplified treatment) or superimposing, so that the joint of the aluminum and nickel sheets is rigid and flat, and an aluminum oxide film can be removed quickly with a rotary steel wire brush. Then, additive-containing aluminum welding solder wires are applied by melt-coating (brazing) with a soldering iron, and welding can be completed firmly and quickly (about two seconds). Scald due to long-time introduction of high temperature into the cells is avoided. Compared with the existing grouping method, the connection resistance can be reduced, high current can be borne, less heat is produced, bump can be resisted, and the hidden danger of thermal runaway can be reduced. A pure nickel sheet can be replaced with a nickel-plated copper strip without copper-aluminum reaction, and the cost can be reduced. The soft-packed power ternary lithium battery can be used in all kindsof electric cars, unmanned aerial vehicles, two-wheeled and three-wheeled electric vehicles, and the like.

Description

[0001] Technical Field The present invention relates to lithium battery pack technology. Background technique [0002] We know that batteries are all about small size and light weight - high energy density. This is especially true as a power lithium battery for new energy lithium-ion vehicles, two-wheeled and three-wheeled electric vehicles, and drones. Therefore, due to low energy density and short battery life, lithium iron phosphate batteries are withdrawing from the market and replaced by "nickel-cobalt-manganese" ternary lithium. The same ternary lithium raw material, due to different manufacturing processes, forms two types of monomers: hard shell (aluminum shell, steel shell) and soft shell. The "positive electrode material" and "negative electrode material" are separated by a "diaphragm" in the middle, and they are trinity. If they are wound and formed, they will be made into hard-shell cylindrical or square battery cells (cells); if they are folded back and forth and...

AI Technical Summary

Problems solved by technology

But there are still deficiencies: 1. Like the spot welding machine, it belongs to the "point to surface", which converts the conductive surface into points; to make up enough points, it is necessary to make a lot of points, which is actually time-consuming. The laser head wears out and the replacement rate higher

2. It is inevitable that there will be a small number of "points", which are soldered and turned over - resulting in a "short board effect", which makes the entire group's overvoltage discounted.

Third, it is not suitable for low-cost "nickel-plated copper strip" - the nickel-plated film of the adapter is very thin, and laser spot welding is also fusion welding (spot fusion welding) and "piercing", which will separate the copper and the positive electrode. If the aluminum is directly fused together, this "point" will definitely produce a redox reaction and become a "virtual point", which cannot withstand repeated bumps

[0008] Finally, there is a "common problem" in all the above-mentioned processes - the aluminum oxide film on the surface of the aluminum pole piece is sandwiched between the adapter piece, "a mixed bag of fish and dragons", and will continue to proliferate in the future, affecting over-current and increasing internal resistance , increased fever

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