Pretreatment method for welding positive and negative aluminum wires of cylindrical lithium ion battery cell

Abstract

The present application relates to the technical field of battery manufacturing, and discloses a cylindrical lithium ion battery cell positive and negative pole aluminum wire welding pretreatment method, specifically comprising the following steps: S11: sequentially placing cylindrical lithium ion batteries on a pretreatment conveying belt; S12: adjusting the laser energy percentage of a continuous pulse laser and controlling the laser emission time of the continuous pulse laser, so that the continuous pulse laser arranged above the pretreatment conveying belt cleans the positive polarity surface of the cylindrical lithium ion battery; S13: the pretreatment conveying belt drives the cylindrical lithium ion battery to move to a movable clamping mechanism with a lifting function. The present application adjusts the laser energy percentage of the continuous pulse laser, the laser emission time of the continuous pulse laser, and the laser focal point position of the continuous pulse laser to control the ablation intensity of the positive polarity surface of the cylindrical lithium ion battery or the negative polarity surface of the cylindrical lithium ion battery, thereby ensuring that the positive and negative polarity surfaces of the cylindrical lithium ion battery cell are cleaned by laser cleaning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery manufacturing, in particular to a cylindrical lithium ion battery cell positive and negative pole aluminum wire welding pretreatment method. BACKGROUND

[0002] In the process of making cylindrical lithium ion battery into a battery pack, the aluminum wire ultrasonic welding process method introduced from the semiconductor industry is used to realize the series and parallel connection of single cylindrical lithium ion battery, but due to the fact that the cylindrical lithium ion battery in the battery industry will be sprayed with rust-proof oil before leaving the factory to prevent the battery cell from rusting, a layer of rust-proof oil layer will exist on the positive and negative poles of the cylindrical lithium ion battery, and the single cylindrical lithium ion battery will be contaminated with oil stains, sweat, dust, dirt and other undesirable foreign matters during the process of handling, transferring, transferring and assembling into a group, which will have adverse effects on the ultrasonic welding of the positive and negative poles of the cylindrical lithium ion battery pack, resulting in virtual welding, or even the aluminum wire cannot be welded to the positive and negative poles of the cylindrical lithium ion battery pack.

[0003] The current industry uses a process method of using cotton dipped in alcohol to wipe the positive and negative poles of the cylindrical lithium ion battery before ultrasonic welding to improve the welding yield of the aluminum wire, but the current alcohol wiping process method often cannot quantitatively confirm whether the wiping is clean or not after wiping, and even causes secondary pollution of the positive and negative poles of the cylindrical lithium ion battery after wiping, which makes the welding yield of the aluminum wire ultrasonic welding of the positive and negative poles of the cylindrical lithium ion battery pack after wiping not obvious, and even the welding yield is lower. SUMMARY

[0004] The present application provides a cylindrical lithium ion battery cell positive and negative pole aluminum wire welding pretreatment method, which ensures the laser cleaning of the positive and negative poles of the cylindrical lithium ion battery pack, and further improves the ultrasonic welding yield of the positive and negative poles of the cylindrical lithium ion battery pack, and solves the problem that the alcohol wiping process method often cannot quantitatively confirm whether the wiping is clean or not after wiping, and even causes secondary pollution of the positive and negative poles of the cylindrical lithium ion battery after wiping.

[0005] The present application is realized as follows: a cylindrical lithium ion battery cell positive and negative pole aluminum wire welding pretreatment method, specifically comprising the following steps:

[0006] S11: placing the cylindrical lithium ion battery on the pretreatment conveying belt in sequence;

[0007] S12: adjusting the laser energy percentage of the continuous pulse laser and controlling the laser emission time of the continuous pulse laser, so that the continuous pulse laser arranged above the pretreatment conveying belt cleans the positive pole of the cylindrical lithium ion battery;

[0008] S13: The pre-treatment conveying belt drives the cylindrical lithium ion battery to the moving clamping mechanism with lifting function;

[0009] S14: The moving clamping mechanism clamps the cylindrical lithium ion battery and moves it to the upper side of the second continuous pulse laser, at which the second continuous pulse laser cleans the negative polarity surface of the cylindrical lithium ion battery.

[0010] S15: After the negative polarity surface of the cylindrical lithium ion battery is cleaned, the cylindrical lithium ion battery is placed on the welding conveying belt for welding process.

[0011] Further, the continuous pulse laser emits laser vertically on the positive polarity surface of the cylindrical lithium ion battery and the negative polarity surface of the cylindrical lithium ion battery, and the energy percentage of the continuous pulse laser is 40-80%, and the continuous pulse laser emits laser for 50-100 ms.

[0012] Further, the continuous pulse laser generates a continuous pulse laser focal point when emitting laser, and the distance between the continuous pulse laser focal point and the positive polarity surface of the cylindrical lithium ion battery or the negative polarity surface of the cylindrical lithium ion battery is set to 0-0.5 mm.

[0013] Further, the maximum emission power of the continuous pulse laser is 20 W, and the actual emission power is 20*adjustment of the energy percentage of the continuous pulse laser.

[0014] Further, the moving clamping mechanism comprises a fixed plate, and a sliding groove is arranged on the upper part of the fixed plate, and a sliding block is arranged in the sliding groove.

[0015] Further, a sliding sleeve is arranged in the middle part of the sliding block, and a hydraulic rod is sleeved in the sliding sleeve.

[0016] Further, positioning plates are vertically arranged at both ends of one side of the sliding block, a clamping groove is formed between the positioning plates, a connecting plate is arranged in the clamping groove, and a torsion spring pin is arranged on one side of the connecting plate.

[0017] Further, clamping arms are hinged on both sides of the torsion spring pin, the two clamping arms are arranged in an arc shape, and an anti-skid layer is arranged on the inner wall of the clamping arms.

[0018] Further, a connecting pin is arranged between the connecting plate and the positioning plate, the connecting pin extends to the outside of the positioning plate on both sides, a limiting head is arranged at the end of the connecting pin, and a pin movable groove matched with the connecting pin is arranged on the positioning plate.

[0019] Further, the two positioning plates are provided with extrusion surfaces on the side ends facing each other, which will extrude the clamping arms when the clamping arms are retracted, and the clamping arms are extruded to clamp and fix the cylindrical lithium ion battery.

[0020] Compared with the prior art, the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method provided by the application has the following beneficial effects:

[0021] 1. The ablation intensity of the positive or negative surface of the cylindrical lithium ion battery is controlled by adjusting the laser energy percentage of the continuous pulse laser, the laser emission time of the continuous pulse laser, and the laser focal point position of the continuous pulse laser, so as to ensure the cleaning of the positive and negative surfaces of the cylindrical lithium ion battery cell by laser cleaning, and to improve the yield of the ultrasonic welding of the positive and negative aluminum wires of the cylindrical lithium ion battery cell.

[0022] 2. The process method of using the continuous pulse laser to vertically irradiate the positive and negative surfaces of the cylindrical lithium ion battery can quickly ablate the oil stains, sweat, dust, dirt and other undesirable foreign matters remaining on the positive and negative surfaces of the cylindrical lithium ion battery, so as to ensure the ultrasonic welding of the clean positive and negative surfaces of the cell, and the moving clamping mechanism is provided with lifting function, the cylindrical lithium ion battery is sleeved by lifting, and then the other electrode surface is cleaned by moving and extruding clamping, and after cleaning, it is placed on the welding conveying belt for next process, and the degree of mechanization is high. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The flowchart of the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method provided by the application is shown in the figure.

[0024] Figure 2 The schematic diagram of the pretreatment equipment in the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method provided by the application is shown in the figure.

[0025] Figure 3 The continuous pulse laser processing principle diagram in the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method provided by the application is shown in the figure.

[0026] Figure 4 The structure schematic diagram of the moving clamping mechanism in the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method provided by the application is shown in the figure.

[0027] In the figure: 1-continuous pulse laser, 2-laser, 3-laser emitting focal point of continuous pulse laser, 4-positive polarity surface of cylindrical lithium ion battery, 5-cylindrical lithium ion battery, 6-negative polarity surface of cylindrical lithium ion battery, 11-preprocessing conveyor belt, 12-moving clamping mechanism, 121-fixed plate, 122-slotted guide, 123-sliding block, 124-hydraulic rod, 125-positioning plate, 126-connection plate, 127-torsion spring pin, 128-clamping arm, 129-connection pin, 1210-pin active slot, 1211-sliding sleeve, 13-welding conveyor belt. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0029] The implementation of the present application is described in detail below in combination with specific examples.

[0030] The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0031] Examples

[0032] Referring to Figures 1-4 The cylindrical lithium ion battery pack cell positive and negative aluminum wire welding preprocessing method specifically includes the following steps:

[0033] S11: placing the cylindrical lithium ion battery 5 on the preprocessing conveyor belt 11 in turn;

[0034] S12: adjusting the percentage of laser energy emitted by the continuous pulse laser, and controlling the laser emission time of the continuous pulse laser, so that the continuous pulse laser 1 provided above the preprocessing conveyor belt 11 cleans the positive polarity surface 4 of the cylindrical lithium ion battery;

[0035] S13: the preprocessing conveyor belt 11 drives the cylindrical lithium ion battery 5 to move to the moving clamping mechanism 12 with lifting function;

[0036] S14: The moving clamping mechanism 12 clamps the cylindrical lithium ion battery 5 and moves to the top of the second continuous pulse laser 1, at which time the second continuous pulse laser 1 cleans the negative polarity surface 6 of the cylindrical lithium ion battery;

[0037] S15: After the negative polarity surface 6 of the cylindrical lithium ion battery is cleaned, the cylindrical lithium ion battery 5 is placed on the welding conveyor belt 13 for welding, and the continuous pulse laser 1 emits laser 2 vertically irradiating the positive polarity surface 4 and the negative polarity surface 6 of the cylindrical lithium ion battery, the continuous pulse laser emits laser energy percentage is 40-80%, the continuous pulse laser emits laser time range is 50-100ms, the continuous pulse laser 1 generates continuous pulse laser emitting laser focus 3 when emitting laser, and the continuous pulse laser emitting laser focus is located at the interval between the positive polarity surface 4 and the negative polarity surface 6 of the cylindrical lithium ion battery. The interval is set to 0-0.5mm.

[0038] In this embodiment, the maximum emission power of the continuous pulse laser 1 is 20W, and the actual emission power is 20*adjust the continuous pulse laser emission energy percentage value.

[0039] In this embodiment, the moving clamping mechanism 12 includes a fixed plate 121, the upper part of the fixed plate 121 is provided with a sliding groove 122, the sliding groove 122 is provided with a sliding block 123, the middle part of the sliding block 123 is provided with a sliding sleeve 1211, the sliding sleeve 1211 is sleeved with a hydraulic rod 124, the two ends of one side of the sliding block 123 are vertically provided with positioning plates 125, the positioning plates 125 form a clamping groove therebetween, the clamping groove is provided with a connecting plate 126, one side of the connecting plate 126 is provided with a torsional spring pin 127, the two sides of the torsional spring pin 127 are hinged with clamping arms 128, the two clamping arms 128 are arc-shaped, and a non-slip layer is arranged on the inner wall of the clamping arm 128.

[0040] Specifically, for the moving clamping mechanism 12 with lifting function, the end of the hydraulic rod 124 can be arranged on the lead screw block to realize movement, and the lifting hydraulic cylinder is arranged on the lead screw block to realize the effect of the moving clamping mechanism 12 of the technical scheme, so that the sliding block 123 and the sliding groove 122 cooperate to realize the clamping effect of the clamping arm 128 when the hydraulic rod 124 is retracted, and the lifting sliding block 123 and the sliding groove 122 will not be separated, and the lower part of the sliding block 123 is through the sliding groove 122, so that the bottom of the sliding block 123 falls in the sliding groove 122.

[0041] Specifically, the two ends of the torsion spring pin 127 are supported on the inner side of the clamping arm 128, so that when the clamping arm 128 is not subjected to external force, the force acting on the torsion spring pin 127 is the tension of the clamping arm 128, and when subjected to extrusion, the clamping arm 128 will automatically clamp, at which time the torsion spring pin 127 is deformed under pressure, and after the external force is removed, the clamping arm 128 will be expanded again under the action of the torsion spring pin 127.

[0042] In this embodiment, a connecting pin 129 is arranged through the connecting plate 126 and the positioning plate 125, the two sides of the connecting pin 129 extend to the outer side of the positioning plate 125, and a limiting head is arranged at the end of the connecting pin 129, and a pin movable groove 1210 matched with the connecting pin 129 is arranged on the positioning plate 125, and the side end heads of the two positioning plates 125 are provided with extrusion surfaces, which will be extruded with the clamping arm 128 when the clamping arm 128 is contracted, at which time the clamping arm 128 is extruded to clamp and fix the cylindrical lithium ion battery 5.

[0043] The technical scheme adjusts the percentage of laser energy emitted by the continuous pulse laser, the laser emission time of the continuous pulse laser, and the laser focus position of the continuous pulse laser to control the ablation intensity of the positive polarity surface 4 or the negative polarity surface 6 of the cylindrical lithium ion battery, so as to ensure that the positive and negative polarity surfaces of the cylindrical lithium ion battery cell are cleaned by laser, and the process method of using the continuous pulse laser 1 to emit laser vertically to the positive and negative polarity surfaces of the cylindrical lithium ion battery can quickly ablate the oil stains, sweat, dust, dirt impurities and other undesirable foreign matters remaining on the positive and negative polarity surfaces of the cylindrical lithium ion battery, so as to ensure that the clean positive and negative polarity surfaces of the cell are subjected to aluminum wire ultrasonic welding, and the moving clamping mechanism 12 is provided with lifting function, the cylindrical lithium ion battery 5 is sleeved by lifting, and then the other electrode surface is cleaned by moving extrusion clamping, and after cleaning, the next process is carried out on the welding conveying belt, and the degree of mechanization is high.

[0044] In this embodiment, the entire operation process can be controlled by a computer, supplemented by PLC and the like, to realize automatic operation control, and in each operation link, sensors can be arranged to feedback signals, so that the steps are sequentially performed, which are all conventional knowledge of automatic control, and will not be described one by one in this embodiment.

[0045] Experimental Examples

[0046] The inventors conducted experiments on the technical solution. Four 18650 cylindrical lithium ion battery pack samples were prepared, all of which used the same batch of cells to ensure that the positive and negative polarity surfaces of all the cells were the same. Then the four samples were cleaned and ultrasonically welded with aluminum wire on the positive and negative polarity surfaces according to the following process. The same aluminum wire ultrasonic welding machine was used for welding, and the same person operated the machine.

[0047] Sample ① used clean cotton cloth to wipe the positive and negative polarity surfaces of the cells with 99.99% pure alcohol, and then used an aluminum wire ultrasonic welding machine to ultrasonically weld the positive and negative polarity surfaces of the cells.

[0048] Sample ② used a continuous pulse laser to vertically irradiate the positive and negative poles of the cylindrical lithium ion cell. The continuous pulse laser emitted a laser energy percentage of 40%, a laser emission time of 100 ms, and a laser focal point located 0 mm above the positive and negative polarity surfaces. Then an aluminum wire ultrasonic welding machine was used to ultrasonically weld the positive and negative polarity surfaces of the cells.

[0049] Sample ③ used a continuous pulse laser to vertically irradiate the positive and negative poles of the cylindrical lithium ion cell. The continuous pulse laser emitted a laser energy percentage of 60%, a laser emission time of 80 ms, and a laser focal point located 0.25 mm above the positive and negative polarity surfaces. Then an aluminum wire ultrasonic welding machine was used to ultrasonically weld the positive and negative polarity surfaces of the cells.

[0050] Sample ④ used a continuous pulse laser to vertically irradiate the positive and negative poles of the cylindrical lithium ion cell. The continuous pulse laser emitted a laser energy percentage of 80%, a laser emission time of 50 ms, and a laser focal point located 0.5 mm above the positive and negative polarity surfaces. Then an aluminum wire ultrasonic welding machine was used to ultrasonically weld the positive and negative polarity surfaces of the cells.

[0051] After the ultrasonic aluminum wire welding of the above four samples was completed, the four samples were sequentially placed into the same aluminum wire welding tension testing machine for ultrasonic welding tension testing. The tension testing standard was that the aluminum wire ultrasonic welding fillet was not allowed to have any lifting, pulling off, or breaking when the aluminum wire tension reached 250 g.

[0052] Through the above sample tests, the cylindrical lithium ion battery cell positive and negative aluminum wire welding pretreatment method implemented by the last four samples and the measured aluminum wire ultrasonic welding yield are shown in Table 1.

[0053] Table 1:

[0054]

[0055] In Table 1, the experimental example 1 is a conventional process method for improving the ultrasonic welding yield of the positive and negative aluminum wires of the cylindrical lithium ion battery cell, which uses 99.99% pure alcohol to wipe the positive and negative polarity surfaces of the cylindrical lithium ion battery cell before ultrasonic welding of the aluminum wires;

[0056] The process method for improving the ultrasonic welding yield of the positive and negative aluminum wires of the cylindrical lithium ion battery cell in the experimental example 2 is to use a continuous pulse laser to vertically irradiate the positive and negative electrodes of the cylindrical lithium ion cell, the continuous pulse laser emits laser energy percentage of 40%, the continuous pulse laser emits laser time of 100ms, the continuous pulse laser emits laser focus point above the positive and negative polarity surfaces of the cell 0mm, and then use the aluminum wire ultrasonic welding machine to perform aluminum wire ultrasonic welding on the wiped positive and negative polarity surfaces of the cell;

[0057] The process method for improving the ultrasonic welding yield of the positive and negative aluminum wires of the cylindrical lithium ion battery cell in the experimental example 3 is to use a continuous pulse laser to vertically irradiate the positive and negative electrodes of the cylindrical lithium ion cell, the continuous pulse laser emits laser energy percentage of 60%, the continuous pulse laser emits laser time of 80ms, the continuous pulse laser emits laser focus point above the positive and negative polarity surfaces of the cell 0.25mm, and then use the aluminum wire ultrasonic welding machine to perform aluminum wire ultrasonic welding on the wiped positive and negative polarity surfaces of the cell;

[0058] The process method for improving the ultrasonic welding yield of the positive and negative aluminum wires of the cylindrical lithium ion battery cell in the experimental example 4 is to use a continuous pulse laser to vertically irradiate the positive and negative electrodes of the cylindrical lithium ion cell, the continuous pulse laser emits laser energy percentage of 80%, the continuous pulse laser emits laser time of 50ms, the continuous pulse laser emits laser focus point above the positive and negative polarity surfaces of the cell 0.5mm, and then use the aluminum wire ultrasonic welding machine to perform aluminum wire ultrasonic welding on the wiped positive and negative polarity surfaces of the cell;

[0059] The aluminum wire welding yield results in Table 1 show that the sample of the present application uses a continuous pulse laser to vertically irradiate the positive and negative electrodes of the cylindrical lithium ion cell, the continuous pulse laser emits laser energy percentage in the range of 40% to 80%, the continuous pulse laser emits laser time in the range of 50 to 100ms, the continuous pulse laser emits laser focus point above the positive and negative polarity surfaces of the cell in the range of 0 to 0.5mm, and the aluminum wire welding yield of the positive and negative polarity surfaces of the cylindrical cell samples ②③④ is 98.6% to 99.5%. Compared with the sample ① which uses the traditional alcohol wiping method to wipe the positive and negative polarity surfaces of the cylindrical cell before ultrasonic welding of the aluminum wires, the aluminum wire welding yield is greatly improved from 46.8% to 98.6% to 99.5%, which reduces the intensity of employee rework and repair work, reduces unnecessary rework and repair time, reduces production cost, and improves the quality of ultrasonic welding of the positive and negative aluminum wires of the cylindrical lithium ion battery cell.

[0060] The laser energy percentage emitted by the continuous pulse laser, the laser emission time of the continuous pulse laser, the laser focus position of the continuous pulse laser emitted by the continuous pulse laser control the ablation intensity of the positive polarity surface 4 or the negative polarity surface 6 of the cylindrical lithium ion battery, so as to ensure the laser cleaning of the positive and negative polarity surfaces of the cylindrical lithium ion battery cell, and the process method of using the continuous pulse laser 1 to emit laser to vertically irradiate the positive and negative polarity surfaces of the cylindrical lithium ion battery. The oil stains, sweat, dust, dirt and other impurities on the positive and negative polarity surfaces of the cylindrical lithium ion battery can be quickly ablated, so as to ensure that the clean positive and negative polarity surfaces of the cell are subjected to aluminum wire ultrasonic welding.

[0061] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pretreatment method for welding aluminum wires to the positive and negative electrodes of cylindrical lithium-ion battery cells, characterized in that, Specifically, the steps include the following: S11: Place the cylindrical lithium-ion batteries sequentially on the pretreatment conveyor belt; S12: Adjust the laser energy percentage of the first continuous pulse laser set above the pretreatment conveyor belt to 40-80%, and control its laser emission time to 50-100ms. At the same time, set the distance between the laser focus and the positive electrode surface of the cylindrical lithium-ion battery to 0-0.5mm, so that the continuous pulse laser cleans the positive electrode surface of the cylindrical lithium-ion battery. S13: The pre-processing conveyor belt then moves the cylindrical lithium-ion battery to a position below a mobile clamping mechanism with lifting function. The mobile clamping mechanism includes a pair of clamping arms with arc-shaped inner walls and anti-slip layers. The mobile clamping mechanism includes a fixed plate. A groove is provided on the upper part of the fixed plate. A slider is provided in the groove. A sliding sleeve is provided in the middle of the slider. A hydraulic rod is sleeved inside the sliding sleeve. Positioning plates are vertically provided at both ends of one side of the slider. A clamping groove is formed between the positioning plates. A connecting plate is provided in the clamping groove. A torsion spring pin is provided on one side of the connecting plate. A pressing surface is provided on the opposite ends of the two positioning plates. When the clamping arms retract, the pressing surface will press against the clamping arms. At this time, the clamping arms are pressed and clamped to complete the clamping and fixing of the cylindrical lithium-ion battery. S14: The moving clamping mechanism descends and clamps the cylindrical lithium-ion battery by contracting and squeezing the side of the clamping arm, then lifts and moves to be directly above the second continuous pulse laser. Adjust the emission laser energy percentage of the second continuous pulse laser to 40-80%, the emission time to 50-100ms, and the distance between the laser focus and the negative polarity surface to 0-0.5mm to clean the negative polarity surface of the cylindrical lithium-ion battery. S15: After cleaning the negative polarity surface of the cylindrical lithium-ion battery, the moving clamping mechanism places the cylindrical lithium-ion battery on the welding conveyor belt for welding.

2. The pretreatment method for welding positive and negative aluminum wires in cylindrical lithium-ion battery cells as described in claim 1, characterized in that, The maximum emission power of the continuous pulse laser is 20W, and its actual emission power is 20 * the percentage value of the laser energy emitted by the adjusted continuous pulse laser.

3. The pretreatment method for welding positive and negative aluminum wires in cylindrical lithium-ion battery cells as described in claim 2, characterized in that, A connecting pin is provided through the connecting plate and the positioning plate. Both sides of the connecting pin extend to the outer side of the positioning plate, and a limiting head is provided at the end of the connecting pin. The positioning plate is provided with a pin movable groove that matches the connecting pin.

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