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

A soft-pack lithium battery and tin brazing technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problems of laser head loss, high replacement rate, can not withstand repeated bumps, and affect over-power, etc. The effect of increasing cost and flight weight, avoiding system errors, and ensuring flight safety

Pending Publication Date: 2019-10-15

胡景辉

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AI-Extracted 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 spo...

Method used

[0019] Fig. 3, after the pre-tightened single battery cell 1 of the spot welding method has completed nickel brazing, i...

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.

Application Domain

Cell component detailsSoldering auxillary devices

Technology Topic

Thermal runawayCopper tape +20

Image

Examples

Experimental program(1)

Example Embodiment

[0016] The present invention will be further described below in conjunction with the drawings and embodiments.

[0017] From simple to complex, first introduce the use of traditional spot welding, hot pressing method of pre-fastening. see figure 1 , The soft package monomer 1 has a pressing edge 2 around it, and the front end has a negative electrode sheet 3 and a positive aluminum sheet 4. As long as the positive aluminum sheet 4 has a few "points", the solder joint 5 can pre-fasten the adapter sheet 6. Naturally formed slightly warped micro slits 7 Use the rotating wire brush head 8 to polish the aluminum surface of the joint—including micro slits 7, remove the aluminum oxide surface layer, and rub the nickel surface 9 of the adapter piece by the way.

[0018] Then you can use the aluminum solder wire containing flux to quickly complete the soldering of the two by the soldering iron tip. see figure 2.

[0019] image 3 After the single cell 1 pre-fastened by the spot welding method has completed the nickel brazing, it is connected with another single cell by positive and negative brazing, which can quickly eat tin and combine.

[0020] The tin brazing method of superimposed pre-tightening is introduced below. see Figure 4 , Narrow tab type monomer, first fold the two corners of the positive aluminum tab 4 and the adapter sheet 6, and then Figure 5 Horizontal folding and double folding ensure that the adapter plate will not move up and down, left and right, front and rear. The rotating wire brush head quickly and effectively removes the film, and completes the soldering of the anode to nickel. The tin soldering part 7 indicates that the output current area of the aluminum tab is not less than that of the aluminum tab, that is, the "face-to-face" transfer and nickel transfer, and the output is not discounted. Image 6 It indicates that the head end of the transfer piece is folded back to facilitate the next step.

[0021] Wide tab ear type monomer, see Figure 7 , First superimpose the two corners of the positive aluminum tab 4 and the horizontal transition piece 6 once, and then superimpose once again, such as Figure 8 , The second angle is folded to complete the fixation of the adapter piece, and the soldering part 7 can be quickly soldered to complete the positive electrode to nickel. It should be noted that during the actual operation of stacking, the adapter sheet is under the anode aluminum tab. After the stacking is fixed, tinned to nickel, the other side of the adapter sheet is exposed, which is convenient to be used as the main positive electrode and soldered Thick red power cord.

[0022] The above-mentioned superimposed pre-fastened "positive to nickel" tin brazing method of wide and narrow tabs, the same principle, is mainly used for direct connection of positive and negative in series (eliminates all monomers that must be converted to nickel first , Then concatenate)! For the cell thickness of less than 11mm, remove the film and weld a pair of positive and negative electrodes, then use a flame-retardant plate to separate the poles and pads, and then stack a single cell, stack the two poles, remove the film, and weld a pair Positive and negative poles... Specially stacked fixtures and robots can be developed. For the cell thickness of more than 11mm, you can first stack a pair of positive and negative electrodes, remove the film, then stack a single cell, stack the two poles and then remove the film...Finally, the whole group, one stack, one by one Upper tin. According to our experience, within ten minutes, the alumina film will not regenerate in a large area and will not affect the firmness of soldering.

[0023] Picture 9 It shows that the traditional spot welding method of positive poles is pre-fastened and connected in parallel (“two-in-one”). Emphasize: The difficulty of the soft pack lithium battery group is the treatment of the positive aluminum tab 4, but the nickel (nickel-plated copper strip) negative electrode is very easy to be connected with tin, which can eliminate the spot welding connection and directly solder it. The two aluminum lugs 4, with the adapter piece 6, simplify spot welding, "click until", just hang it up, and the soldering part 7 is the guarantee of stable connection and trouble-free!

[0024] Figure 10-12 The indication is that after the positive electrode is pre-fastened in the stacking method, the cells are connected in parallel ("two-in-one"). (It is very easy to solder the nickel anode in parallel, so the introduction and illustration are omitted). In turn, look first Picture 10 , Since the aluminum-plastic pressing edge, the upper and lower aluminum tabs, and the upper adapter are all soft, pinch them together first. Look again Picture 11 , After the "three-in-one" is superimposed, the first welding pool is to weld the lower aluminum lug and the adapter piece. See you last Picture 12 , Fold the adapter sheet back, wipe the welding pool second, and weld the upper aluminum tab with the adapter sheet. Complete the common conversion to nickel and parallel connection of the two positive aluminum tabs.

PUM

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