KR101807868B1 - Manufacturing Method of Battery Pack - Google Patents

Abstract

The present invention relates to a battery pack manufacturing method. The method includes: a step (a) of attaching insulation tape from (+) pole to (-) pole of a battery cell; a step (b) of spot-welding a protecting circuit and a temperature sensor to the battery cell in a regular position; a step (c) of placing the protecting circuit and then curving the temperature sensor; a step (d) of inserting the battery cell into a jig and spot-welding a (+) lead plate of the protecting circuit, and then, spot-welding the protecting circuit to the (-) pole of the battery cell; a step (e) of assembling a frame with the upper surface of the battery cell; a step (f) of measuring the voltage, internal resistance, and temperature resistance value regarding the battery cell; and a step (g) of installing the battery cell in a terminal telephone for inspection to inspect the state of charge by whether a charge lamp is turned on or not. As such, the present invention is capable of integrating the protecting layer with the temperature sensor, reducing a battery cell manufacturing process, reducing manufacturing costs with a decrease in workforce, and reducing costs for handling defective battery cells as well as decreasing the defect rate by improving the assembly properties of a battery cell.

Description

[0001] The present invention relates to a manufacturing method of a battery pack,

The present invention relates to a method of manufacturing a battery pack, and more particularly, to a method of manufacturing a battery pack in which a protection circuit and a temperature sensor are integrally mounted to reduce assembling performance and defect rate of the battery pack.

Generally, the demand for secondary batteries for PDAs, mobile phones, notebook computers, etc. for portable electronic devices for information and communication, electric bicycles, and electric vehicles is rapidly increasing. In accordance with the trend of downsizing and lightening of electronic devices, miniaturization and weight reduction and high capacity charging and discharging A lithium battery has been put into practical use.

Typical examples of the lithium battery include a lithium battery such as a prismatic or pouch-type lithium battery which can be applied to electronic devices such as mobile phones with a small thickness.

However, a lithium battery such as a square type or a pouch type,

Can not be efficiently used and can not be applied to lithium batteries of various shapes and sizes.

Therefore, there is a demand for a battery cell and a battery pack of a shape having a high capacity by efficiently using the inner space for use in an electronic device such as a cellular phone having a shape and / or size such as streamlined.

Secondary batteries are representative of those capable of being recharged and capable of being increased in capacity, such as nickel-cadmium, nickel-hydrogen and lithium-ion batteries.

Among these, the lithium ion battery has attracted attention as a next generation power source due to its excellent characteristics such as long service life and high capacity.

Among them, the lithium secondary battery has an operating voltage of 3.6 V or higher and is used as a power source for portable electronic devices or several in series to be used in a high-output hybrid vehicle. It operates in comparison with a nickel-cadmium battery or a nickel-metal hydride battery The voltage is three times higher and the energy density per unit weight is also excellent, and the use thereof is rapidly increasing.

The lithium secondary battery can be manufactured in various forms. Typical examples of the lithium secondary battery include a cylinder type and a prismatic type, which are mainly used in a lithium ion battery.

In recent years, a lithium polymer battery which is exposed to light is manufactured in a pouch type having flexibility and its shape is relatively free. In addition, the lithium polymer battery is excellent in safety and light in weight, which is advantageous in reducing the weight and weight of portable electronic devices.

On the other hand, when a high output lithium battery such as a hybrid vehicle is required, several tens to hundreds of battery cells are stacked and connected in series or parallel to obtain a high voltage or a high current.

The battery cell includes a case in which a battery unit and a battery unit are accommodated. The battery unit includes a positive electrode plate, a separator plate, and a negative electrode plate laminated or wound in one direction. The positive electrode plate of the battery unit is electrically connected to the positive electrode tab and the negative electrode tab .

The case is a pouch type case in which the intermediate layer is a metal foil and the inner and outer layers adhered to both surfaces of the metal foil are made of an insulating film, unlike a cylindrical or canned can structure formed of a thick film of gold. The pouch-type case has excellent formability and can bend freely.

At this time, each stacked battery cell is connected in series or in parallel for power connection.

However, in order to connect the stacked battery cells in parallel, a positive electrode tab and a negative electrode tab having the same polarity must be connected in multiple, and a fastening structure for simultaneously connecting two or more electrodes according to the capacity of the cell stack body is required. And the negative electrode tab are mechanically fastened or welded, the assemblability and the production efficiency are further lowered.

For example, Patent Document 1 below discloses a battery cell, a battery pack, and a method of manufacturing the battery cell.

A battery cell, a battery pack, and a method of manufacturing the battery cell according to the following Patent Document 1 include a first electrode, a second electrode, and a film interposed between the first and second electrodes and having at least one surface coated with a thermoplastic polymer A pair of electrode tabs protruding from a side surface of the electrode assembly, and an electrode assembly and an electrolyte solution, the electrode assembly including a separator laminated and wound, a pair of electrode tabs protruding from a side surface of the electrode assembly, And a protection circuit module (PCM) electrically connected to the electrode assembly through the pair of electrode tabs.

The following Patent Document 2 discloses a method of manufacturing a battery cell and a battery cell.

A method of manufacturing a battery cell and a battery cell according to the following Patent Document 2 includes a housing and a battery winding disposed in the housing, Wherein the first electrode surface of the battery winding is joined to the metal base portion of the housing before or after inserting the battery winding into the metal wall portion of the housing in a material bonding manner Bonding the second electrode surface of the battery winding to the current feed through after the insertion of the battery winding into the metal wall.

Wherein the metal cover is joined to the metal wall part in a material coupling manner after the material coupling method of the metal base part is coupled to the metal wall part and after the material coupling method of the second electrode face is coupled to the current feed through, After the material bonding method of the first electrode surface of the battery winding is coupled, the metal base portion is bonded to the metal base portion in a material bonding manner.

Korean Patent Publication No. 10-2014-0104888 Korean Patent Publication No. 10-2017-0021752

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a battery pack in which a protection circuit and a temperature sensor are integrally mounted so as to reduce assembling property and defective rate of the battery pack.

It is another object of the present invention to provide a method of manufacturing a battery pack which can reduce the number of working persons due to the manufacture of the battery pack and reduce the cost of manufacturing the battery pack, .

In order to achieve the above object, a method of manufacturing a battery pack according to the present invention comprises the steps of: (a) attaching an insulating tape in a direction from a positive pole to a negative pole of a battery cell, ) Pole to the jig; (b) spot welding the protection circuit and the temperature sensor to the battery cell, spot-welding the protection plate and the lead plate after performing the tensile strength of the welded lead plate; (c) bending the temperature sensor after one end of the protection circuit is aligned with the (+) pole of the battery cell; (d) spot welding the positive lead plate of the protection circuit by inserting the battery cell into a jig, and spot welding the protection circuit to the negative pole of the battery cell; (e) assembling a frame on an upper surface of the battery cell; (f) measuring a voltage, an internal resistance, and a temperature resistance of the battery cell; (g) inserting the battery cell into an inspection terminal phone and inspecting the state of charge based on whether the charge lamp is turned on.

In the step (b) or (d), the spot welding is characterized in that the electrification voltage is 2.50 to 2.80 V, the electrification time is 1.00 to 2.50 kPa, and the pressing force is 0.2 to 0.4 MPa.

In the step (b) or (d), the spot welding is performed with an aluminum dispersion copper having a diameter of 1.3 to 1.5φ and a fracture strength of 2.5 kgf or more to 5.5 kgf or less.

In step (f), a voltage, an internal resistance, and a temperature resistance value of the battery cell are measured. Then, whether the battery cell is operated at a power of 3.7V or more, an ID resistance value of 1.455 to 1.545 k? .

According to another aspect of the present invention, there is provided a method of manufacturing a battery pack, including the steps of: (a) attaching an insulating plate to a battery cell; (b) mounting the battery cell to the jig and then spot-welding the protection circuit sequentially to the (-) pole and the (+) pole; (c) bending a lead plate on the outer surface of the battery cell, and then bending the lead plate on the basis of the protection circuit and the boundary point of the battery cell; (d) connecting a wire to the battery cell by soldering and then attaching a double-sided tape; (e) cutting a tube attached to an outer surface of the battery cell to insert the battery cell into the tube and then shrinking the tube; (f) inspecting the length of the soldered wire; (g) measuring a voltage and an internal resistance of the battery cell.

In the step (b), the spot welding is characterized in that the energizing voltage is 1.80 to 2.90 V, the energizing time is 1.50 to 2.90 kPa, and the pressing force is 0.2 to 0.4 MPa.

In the step (d), the soldering is performed at a soldering temperature of 370 to 390 DEG C, a soldering time of 1 to 3 seconds, and a soldering height of 0.6 mm or less.

As described above, according to the method for manufacturing a battery pack according to the present invention, the protection circuit and the temperature sensor can be integrally manufactured, and the manufacturing process of the battery cell can be reduced. As a result, And it is possible to improve the assembling performance of the battery cell, thereby reducing the defective rate and reducing the cost due to the failure of the battery cell.

1 is a process diagram showing a method of manufacturing a battery pack according to a preferred embodiment of the present invention;
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a battery pack.

Hereinafter, a method of manufacturing a battery pack according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a method of manufacturing a battery pack according to a preferred embodiment of the present invention includes the steps of: (a) attaching an insulating tape in a direction from a positive pole to a negative pole of a battery cell, (+) Pole to the jig; (b) spot welding the protection circuit and the temperature sensor to the battery cell, spot-welding the protection plate and the lead plate after performing the tensile strength of the welded lead plate; (c) bending the temperature sensor after one end of the protection circuit is aligned with the (+) pole of the battery cell; (d) spot welding the positive lead plate of the protection circuit by inserting the battery cell into a jig, and spot welding the protection circuit to the negative pole of the battery cell; (e) assembling a frame on an upper surface of the battery cell; (f) measuring a voltage, an internal resistance, and a temperature resistance of the battery cell; (g) inserting the battery cell into an inspection terminal phone and inspecting the state of charge based on whether the charge lamp is turned on.

As shown in FIG. 2, a method of manufacturing a battery pack according to a preferred embodiment of the present invention includes: (a) attaching an insulating plate to a battery cell; (b) mounting the battery cell to the jig and then spot-welding the protection circuit sequentially to the (-) pole and the (+) pole; (c) bending a lead plate on the outer surface of the battery cell, and then bending the lead plate on the basis of the protection circuit and the boundary point of the battery cell; (d) connecting a wire to the battery cell by soldering and then attaching a double-sided tape; (e) cutting a tube attached to an outer surface of the battery cell to insert the battery cell into the tube and then shrinking the tube; (f) inspecting the length of the soldered wire; (g) measuring a voltage and an internal resistance of the battery cell.

As shown in FIG. 1, a method of manufacturing a battery pack according to an embodiment of the present invention includes a method of manufacturing an inner pack type in which a label is attached to a battery cell, A method of manufacturing a battery pack according to an embodiment is divided into a method of manufacturing a soft pack type in which a tube is wrapped around an outer surface of a battery pack.

As shown in FIG. 1, the battery cell (not shown) visually confirms the appearance state to check for an abnormality. That is, the battery cell is subjected to a process of checking whether there is a scratch or the like on the outer surface.

One end of the insulating tape is attached to the (+) pole of the battery cell, and the other end of the insulating tape is attached to the side of the battery cell through the (-) pole (S110).

At this time, attach the insulation tape so that the insulation tape does not deviate from the correct position while the (+) and (-) poles are positioned on the top surface.

In addition, the insulation tape is attached so that two sheets are not overlapped or shifted to one side, but are not separated.

In addition, the battery cell is mounted on the jig. At this time, the (+) pole of the battery cell is horizontally placed and stably mounted on the jig.

When the insulating tape is attached and the jig is attached, the electrostatic glove is worn to prevent the static electricity from being generated, and the damage or damage of the battery cell is prevented by using the predetermined tool.

Also, the battery cell should not be dropped, and the dropped battery cell should not be attached to the jig.

Spot welding is performed after the protective circuit (PCM) and the temperature sensor (PTC) are placed on the battery cell. At this time, during the spot welding operation, the two spot welding points are not separated from each other so that the welding electrode is not contacted.

In addition, ceramic tweezers or dedicated jigs are placed on the lead plate of the weld to perform a tensile test. If the weld defect does not occur during the spot welding, the deformed lead plate is flattened.

On the other hand, if welding is poor, it is discarded as a defective product and stored separately. It is of course also possible to check whether burrs are generated by spot welding and to remove burrs that have been generated.

According to the welding operation, the welding state of the temperature sensor is visually checked for breakage or deformation of the battery cell, the protection circuit and the temperature sensor, and whether there is overlapping of two sheets. The state of corrosion, breakage of the battery cell, .

If the eccentricity of the welding rod is less than 2.1 mm, the welding rod should be discarded, and the welding rod should be replaced at a fixed time interval.

The spot welding is carried out at an energizing voltage of 2.50 to 2.80 V, a energizing time of 1.00 to 2.50 m / sec and a pressing force of 0.2 to 0.4 MPa, and a breaking strength of 3 kgf or less is maintained. Aluminum dispersion copper is used for welding.

Further, a lead plate made of a protective circuit and nickel is spot welded (S120).

The welding of the lead plate is also conducted so that the spot of the lead does not deviate from the position of the spot. During the operation, the ceramic tweezers or the exclusive jig are inserted into the lead plate of the weld.

If the welding defect of the lead plate does not occur, the deformed lead plate is spread flat. When a spot welding failure occurs, the battery pack is separately stored and the burrs and the like generated after the spot welding are removed.

Confirm the breakage and deformation of nickel lead plate by spot welding and check whether there is overlapping of two sheets. Check corrosion, breakage, and removal of insulating plate and check welding condition of protective circuit and lead plate.

The spot welding of the lead plate is carried out at an energizing voltage of 2.50 to 2.80 V, a energizing time of 1.00 to 2.50 m / sec, and a pressing force of 0.2 to 0.4 MPa, and a breaking strength of 3 kgf or less is maintained.

On the other hand, the spot welding uses a fixed tool and always wears an earth ring.

Further, the protection circuit is brought into close contact with the end of the (+) pole of the battery cell, and then is seated in the base mold, and the temperature sensor mounted on the base mold is bent (S130).

The temperature sensor is bent in a straight line so as not to be separated from the battery cell at the time of bending the temperature sensor.

To prevent static electricity from occurring during bending operation of the protection circuit and the temperature sensor, it is necessary to work with the electrostatic gloves worn, so that a safe operation is performed so that the battery cell is not detached by using the predetermined tool.

After inserting the battery cell into the jig, the positive lead plate of the protection circuit is spot-welded to the cell plate of the battery cell (S140).

During the spot welding operation, the ceramic tweezers or dedicated jigs are inserted into the lead plate at the welding site at any time to perform a tensile test. The battery cells that are found to be defective in spot welding or tensile testing shall be stored in a separate storage box. Visually check the occurrence of the blade edge of the lead plate after the spot welding operation.

In addition, the burrs generated at the spot welding portion are removed by using the tool and the welding is not performed on the spot portions of the battery cell and the crane plate.

In the spot welding operation, there is no foreign matter or deformation, and whether or not the crack plate is corroded or damaged is visually inspected to identify defective products.

The spot welding uses aluminum-dispersed copper having a diameter of 1.3 to 1.5φ and maintains a fracture strength of 2.5 to 5.5 kgf or less. The spot welding is performed at an energizing voltage of 2.50 to 2.80 V, a energizing time of 1.00 to 2.50 m / sec, and a pressing force of 0.2 to 0.4 MPa.

Also, the temperature sensor of the protection circuit is spot-welded to the (-) pole of the battery cell inserted into the jig, so that the welding electrode is contacted so that the spot is not deviated during the spot welding operation.

In addition, the welded part is subjected to tensile test by inserting ceramic tweezers or dedicated jig into the lead plate of the welded area from time to time.

Such spot welding is carried out after visually confirming breakage or deformation of the temperature sensor, overlapping of two sheets, etc., and confirm corrosion, breakage of the battery cell, lifting of the insulating plate, and the like.

In addition, the spot welding of the protection circuit is performed by lifting up the positive (+) and negative (-) poles by using a test jig such as bamboo, Check the spot strength of the lead plate.

In order to inspect the strength, it is necessary to push the raised part back to its original position and to visually or smell the welded part to see if the leakage occurs.

In the spot-welded battery cell, the front face of the frame is positioned in the direction of looking, and then the upper face of the frame and the terminal are assembled to coincide (S150).

At this time, assemble so as not to cause twisting of the frame, balance maintenance of the terminal surface, and deviation of the terminal.

In order to prevent static electricity from being generated during assembly work of these frames, it is necessary to work with the electrostatic gloves while wearing the earth rings.

The A / S label is attached to the frame at the designated position, and is attached to the correct position using a tweezers or the like.

In addition, A / S label should not use colored label and attach it carefully to prevent it from sticking to the correct position.

The battery cell to which the A / S label is attached measures a voltage, an internal resistance, and a temperature resistance value by a tester jig provided with an inspection rod and a battery tester (S160).

Checking the direction of inspecting the battery cell to check whether the battery cell is overcharged, overdischarged, or overcurrent, and checking whether the voltage is maintained at 3.7V or more.

Also check whether the ID resistance is between 1.455 and 1.545 kΩ and the internal resistance is 180 MΩ, and whether scratches are generated by the test pins. It is judged as a good product or a defective product based on the presence or absence of such voltage and resistance.

Also, check the printing condition of the label, whether or not the jig and the battery cell are adhered to each other, attach the battery cell to the jig with the negative (-) pole to the left, align the label along the guide line of the jig, Attach the label to prevent air bubbles from forming.

After the attachment of the label is completed, the battery cell is detached from the jig, and the label is passed through the labeling roller using the silicon plate to attach the label to the label-unfixed surface.

When attaching such a label, check whether there is bubble generation or foreign matter, and visually inspect whether the label adheres to the correct position and judge it as a good product or a defective product.

In order to prevent static electricity from being generated when attaching the label, an electrostatic glove is worn while wearing, and a predetermined tool is used and an earth ring is always worn.

Also, a battery cell is mounted on the terminal for inspection to check whether or not the battery cell is properly mounted, and it is checked whether there is a problem in detachment of double locking, loosening, or interference fit (S170).

It is inserted into the charger in a state where the battery cell is mounted on the inspection terminal phone to check whether the charging lamp of the inspection terminal phone is turned on for 2 seconds or more.

In other words, it is possible to visually confirm whether the label is misaligned, bubbles, damage to the battery cell, etc., and the double locking, loosening, tight fitting, Check the flashing status of the charging lamp.

Also, check the exterior of the battery cell for dirt, burrs, etc., and wipe the exterior of the battery case with a cloth of solvent solution. If there is any foreign substance on the battery cell terminal, wipe it with a cotton swab with solvent solution. Visually check the external appearance of the terminal when cleaning the terminal terminal.

The terminal terminal is confirmed to be free of apparent abnormality such as slanting, sticking, discoloration, protrusion or depression. In addition, the overall appearance of the battery cell such as foreign matter, scratch, welded state, molded state, and label is visually inspected, and the nonconforming product is stored in a defective box determined by the defect type so as not to mix with good products.

The inner pack type battery cell thus manufactured is put into the electrostatic vinyl separately for packaging only, and the quantity of the battery cell is checked and stored in the packaging box.

As shown in FIG. 2, the soft-pack type battery cell attaches an insulating plate to a battery cell. When the insulating plate is twisted or tilted, a short may occur when the nickel lead plate is bent (S210).

At this time, do not let metal etc. touch the surface of the battery, and do not drop it. In addition, the appearance of corrosion, breakage, leaking, and stamping of the battery cell is checked, and the insulation plate is attached so as to maintain a protruding state within 0 to 0.5 mm from the boundary surface reference.

The battery cell to which the insulation plate is attached is inserted into the jig and the protection circuit is inserted into the jig, and the negative electrode is spot welded (S220).

A tensile test is carried out to check the strength of the spot welding from time to time. After the spot welding is performed, foreign substances such as burrs are removed by welding. At this time, care should be taken not to cause a short circuit of the battery cell.

In addition, it is checked whether the battery cell is corroded or damaged, and the spot electrode is used while confirming the state of polishing.

The spot welding is performed while applying pressure at an energizing voltage of 1.80 to 2.90 V, a energizing time of 1.50 to 2.90 m / sec, and a pressing force of 0.2 to 0.4 MPa. The spot welding rod is made of aluminum-dispersed copper having a diameter of 1.5φ or 3φ, and the fracture strength is maintained at 3 kgf or more.

The battery cell where the (-) pole is spot-welded is mounted on the jig, and the protection circuit is seated.

The battery cell in which the positive (+) and negative (+) poles are welded is taken out of the jig so that the lead plate of the protection circuit is not deformed, the tensile strength according to the spot welding is made occasionally, do. At this time, care should be taken not to cause a short circuit in the battery cell.

The battery cell where the protection circuit is spot-welded first bends the lead plate of the protection circuit with reference to the end of the battery cell (S230).

The bend of the lead plate should not be in contact with the aluminum enclosure and should not bend more than twice. This is to prevent a short circuit from occurring in the battery cell or a short circuit due to deformation of the electrode.

On the other hand, the (+) pole aluminum electrode is easy to be cut by the protective circuit lead plate, so check the condition of the lead plate. Confirming the attachment state of the insulating tape, checking the bending direction and the bent state of the lead plate, and confirming a short circuit with the aluminum casing.

In addition, it is checked whether the lead plate is broken after bending, and the tightness and alignment of the battery cell with the pouch are checked.

Welded to the boundary point between the spot-welded protection circuit and the battery cell to bend the lead plate of the protection circuit. At this time, do not apply excessive force to damage the lead plate.

Solder the wires to the (+) and (-) poles of the battery cell (S240).

Do not overcharge during wire soldering and work with care to prevent impurities and lead balls from falling on the battery during soldering. The soldering temperature is 370 to 390 ° C and the soldering time is 1 to 3 seconds. Do not cause overheating, cold lead, short circuit, and chip damage in the protective circuit during soldering work.

In addition, use the specified tool and always wear an earth ring.

On the other hand, the double-sided tape suitable for the specification of the battery cell is attached to a tape cutter (not shown), the double-sided tape is cut to a length of approximately 30 to 40 mm and attached to cover the upper surface of the battery cell, that is, the protection circuit and the temperature sensor.

Further, the tube attached to the outer surface of the battery cell is cut according to the size of the battery cell, and the cut tube is inserted from the lower side of the battery cell to the upper side so that the tube is positioned in the center of the battery cell (S250).

At this time, please wear electrostatic gloves to avoid static electricity.

After confirming that the tube is inserted in the center of the battery cell, hot air is applied to shrink the tube. Also, after the tube shrinks, press each corner to attach the tube to the battery cell.

In addition, the wire of the battery cell in which the tube shrinking has been completed is inspected to see whether the length of the wire maintains a proper length in a state of being tightly tensioned (S260). At this time, the wire should maintain a length of approximately 34 to 38 mm.

The internal resistance and the voltage of the battery cell to which the tube is attached are measured (S270).

Check internal resistance to 120 ~ 200MΩ and voltage to maintain 3.7V ~ 4.2V. Check the inspection value and specified value of the instrument.

It is needless to say that the internal resistance and the voltage may be changed according to the specification of the battery cell.

A label is attached to the outer surface of the battery cell at a designated position, and the battery cell is pressed by hand to prevent air bubbles from being generated. In addition, the overall appearance of the battery cell such as foreign matters, scratches, and labels is visually inspected, and the connector coupled to the wire is pulled out to check whether the connector is defective. The battery cells determined to be good products are individually wrapped in the electrostatic vinyl.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

Claims (7)

(a) attaching an insulating tape in the direction of the (-) pole from the (+) pole of the battery cell and then placing the (+) pole of the battery cell in the jig;
(b) spot welding the protection circuit and the temperature sensor to the battery cell, spot-welding the protection plate and the lead plate after performing the tensile strength of the welded lead plate;
(c) bending the temperature sensor after one end of the protection circuit is aligned with the (+) pole of the battery cell;
(d) spot welding the positive lead plate of the protection circuit by inserting the battery cell into a jig, and spot welding the protection circuit to the negative pole of the battery cell;
(e) assembling a frame on an upper surface of the battery cell;
(f) measuring a voltage, an internal resistance, and a temperature resistance of the battery cell;
(g) inserting the battery cell into an inspection terminal phone to inspect the state of charge by lighting the charge lamp,
Wherein the welding rod is not contacted so that two spot welding points do not deviate from each other when the spot welding is performed, and when the eccentricity of the welding rod is 2.1 mm or less, the welding rod is discarded. The method according to claim 1,
Wherein the spot welding is performed at an energizing voltage of 2.50 to 2.80 V, a energizing time of 1.00 to 2.50 kPa, and a pressing force of 0.2 to 0.4 MPa in the step (b) or (d). 3. The method of claim 2,
Wherein the spot welding is performed with an aluminum dispersion copper having a diameter of 1.3 to 1.5φ at a breaking strength of 2.5 kgf or more to 5.5 kgf or less in the step (b) or (d) Way. 3. The method of claim 2,
In step (f), a voltage, an internal resistance, and a temperature resistance value of the battery cell are measured. Then, whether the battery cell is operated at a power of 3.7V or more, an ID resistance value of 1.455 to 1.545 k? Wherein the battery pack is attached to the battery pack. (a) attaching an insulating plate to a battery cell;
(b) mounting the battery cell to the jig and then spot-welding the protection circuit sequentially to the (-) pole and the (+) pole;
(c) bending a lead plate on the outer surface of the battery cell, and then bending the lead plate on the basis of the protection circuit and the boundary point of the battery cell;
(d) connecting a wire to the battery cell by soldering and then attaching a double-sided tape;
(e) cutting a tube attached to an outer surface of the battery cell to insert the battery cell into the tube and then shrinking the tube;
(f) inspecting the length of the soldered wire;
(g) measuring a voltage and an internal resistance of the battery cell,
Wherein the welding rod is not contacted so that two spot welding points do not deviate from each other when the spot welding is performed, and when the eccentricity of the welding rod is 2.1 mm or less, the welding rod is discarded. 6. The method of claim 5,
Wherein the spot welding is performed at an energizing voltage of 1.80 to 2.90 V, a energizing time of 1.50 to 2.90 GPa, and a pressing force of 0.2 to 0.4 MPa in the step (b). 6. The method of claim 5,
Wherein, in the step (d), the soldering has a brazing temperature of 370 to 390 DEG C, a brazing time of 1 to 3 seconds, and a brazing height of 0.6 mm or less.

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