JP6511362B2 - Welding equipment - Google Patents

Description

  The present invention relates to a welding apparatus, and more particularly to a welding apparatus suitable for welding a plurality of points of a wound body such as a wound lithium ion battery.

  In recent years, a wound-type lithium ion battery having a shape in which a plurality of flat plate-shaped positive and negative electrodes are stacked via a separator and wound as shown in FIG. 8A has come to be used. There is. In FIG. 8A, 100 is a positive electrode, 101 is a negative electrode, and 102 is a separator. The positive electrode 100 is obtained by applying a lithium-based material to an aluminum (Al) foil, and the negative electrode 101 is obtained by applying a carbon-based material to a copper (Cu) foil.

  The cross-sectional structure which cut | disconnected the cylindrical winding type | mold lithium ion battery shown to FIG. 8 (A) by XZ plane including the central axis of a cylinder is shown to FIG. 8 (B). There is a region where only the Al foil of the positive electrode 100 is laminated at one end of the wound lithium ion battery, and the current collector 103 for external connection is welded to the laminated Al foil. Similarly, at the other end of the wound lithium ion battery, there is a region in which only the Cu foil of the negative electrode 101 is laminated, and a collector 104 for external connection is welded to the laminated Cu foil. Ru.

  Generally, ultrasonic welding, laser welding, and resistance welding are used for welding of the Al foil of the positive electrode 100 to the current collector 103 and welding of the Cu foil of the negative electrode 101 to the current collector 104 (patented) See Literature 1 and Patent Literature 2). Ultrasonic welding is a method of joining by applying ultrasonic vibration parallel to a joining surface while applying pressure in the vertical direction to a workpiece. Laser welding is a method in which a workpiece is irradiated with a laser beam to be melted and joined. Resistance welding is a method of welding by welding a material to be bonded by Joule heat generated by flowing current between the electrodes while sandwiching and pressing a material to be bonded from above and below with a pair of electrodes.

JP, 2008-66170, A JP, 2009-32670, A

Ultrasonic welding has a problem in that fine metal powder is dropped from the battery due to ultrasonic vibration at the time of welding. Further, when the number of Al foils and Cu foils increases, the necessary welding energy increases, so it is necessary to increase the ultrasonic wave output, and there is a possibility that the Al foils and the Cu foils may be broken or broken.
Laser welding has a problem in that high energy laser light is required because the reflectance of Al and Cu is high. In addition, there is a problem that metal powder called sputtering is generated.

  On the other hand, in resistance welding, it is possible to suppress the generation of metal powder and the breakage of the foil which become problems in ultrasonic welding and laser welding. However, when welding the Al foil of the positive electrode 100 to the current collector 103 and welding the Cu foil of the negative electrode 101 to the current collector 104, it is necessary to perform welding at multiple points for reasons such as securing welding strength is there.

However, in resistance welding, when welding is performed one by one, the current is diverted to the already welded point in the second and subsequent weldings, so the current flowing to the welding electrode is increased by the amount of this shunting The problem is that the energy required to obtain a good quality nugget (joint) is increased. In addition, there is a problem that setting of conditions for obtaining high quality nuggets becomes complicated.
The above problems occur not only in the case of lithium ion batteries but also in the case of welding a plurality of points to a laminate of a plurality of Al foils or Cu foils.

  The present invention has been made to solve the above-mentioned problems, and a welding apparatus capable of realizing appropriate welding even when welding at multiple points to a wound body such as a wound lithium ion battery Intended to provide.

  The welding apparatus according to the present invention comprises a wound body having a structure in which a plurality of metal foils are stacked and wound in a spiral shape, and a plate-like member made of metal disposed in contact with the outer peripheral surface of the wound body. And the current collector having a convex projection formed on the wound body, and the plurality of metal foils of the wound body sandwiching the plurality of metal foils so as to face the current collector. Are arranged along the laminating direction of the metal foil so as to face each other with the object to be joined interposed therebetween with respect to the object to be joined, which comprises the plate-like back plate made of metal disposed inside A plurality of sets of first and second electrodes, and two sets of the first and second electrodes provided in the interior of the wound body and facing each other on the inner circumferential surface of the wound body At least one of the faces is in line with the first and second electrodes so as to sandwich the back plate And a pressing mechanism for pressing at least one of the first and second electrodes and sandwiching the bonding object by the first and second electrodes. A plurality of welding power sources provided for each pair of the first and second electrodes and supplying a current between the corresponding first and second electrodes, and one or more welding power sources pertaining to the article to be welded A physical quantity detection means for detecting a physical quantity and a plurality of sets of first and second electrodes are supplied with current from the plurality of welding power sources so that each set starts welding in synchronization, and is detected during welding Control means for stopping energization of the first and second electrodes when one of the physical quantities reaches a predetermined termination condition value, and the plurality of welding power sources have a direction of energization of the object to be welded Supplying current to the plurality of first and second electrodes so as to be identical It is an feature.

Further, in one configuration example of the welding device of the present invention, the control means sets in advance, as a termination condition value, a resistance between the first and second electrodes, which is a physical quantity detected during welding. After performing welding of the first control method n times to stop energization of the first and second electrodes when the inter-electrode resistance value is reached (n is an integer of 1 or more), the first It is characterized in that welding of a second control method different from the control method is performed m times (m is an integer of 1 or more).
In one configuration example of the welding device of the present invention, the welding of the second control method is performed when the physical quantity other than the inter-electrode resistance detected during welding reaches a predetermined termination condition value. It is welding which stops energization to the 2nd electrode, and physical quantities other than resistance between the electrodes are welding current which flows through the 1st and 2nd electrodes, welding applied between the 1st and 2nd electrodes The voltage, the welding power supplied to the first and second electrodes, the load applied to the article, and the displacement of the article in the thickness direction.
Further, in one configuration example of the welding device of the present invention, the welding of the second control method is a welding of a constant current control method of supplying a predetermined welding current to the first and second electrodes for a fixed time, 1, welding of constant voltage control method of supplying a predetermined welding voltage for a fixed time between the second electrode and welding of constant power control method of supplying a predetermined welding power to the first and second electrodes for a predetermined time It is.
Further, in a configuration example of the welding device according to the present invention, the control means waits for completion of welding of the slowest one of the plurality of first and second electrodes when welding is performed a plurality of times. After that, a current is supplied from the plurality of welding power sources to the plurality of sets of first and second electrodes so that each set synchronously starts welding, and the next welding is performed. is there.

Further, one configuration example of the welding device according to the present invention further includes an adsorption mechanism which vacuum-sucks the back plate and fixes it on the surface of the third electrode facing the inner peripheral surface of the wound body. It is characterized by
Further, according to one configuration example of the welding device of the present invention, further, after completion of welding, the third electrode is pulled out from the article along the axial direction of the wound body, or the shaft of the wound body An insertion / extraction mechanism for pulling out the object from the first, second, and third electrodes along a direction, and a force required for the insertion / extraction mechanism to withdraw the third electrode from the object, or It comprises the alarm notification means which emits an alarm, when the force required to withdraw the said to-be-joined object from 1st, 2nd, 3rd electrode is below a predetermined threshold.
Further, according to one configuration example of the welding device of the present invention, further, after completion of welding, the third electrode is pulled out from the article along the axial direction of the wound body, or the shaft of the wound body A vacuum pressure detection means for detecting the vacuum pressure of the suction mechanism, a mechanism for pulling out the object to be bonded from the first, second and third electrodes along the direction, and When the vacuum pressure detected by the vacuum pressure detection means is less than or equal to a predetermined threshold value when the third electrode is pulled out or when the object to be bonded is pulled out from the first, second and third electrodes , And alarm notification means for emitting an alarm.

  According to the present invention, a plurality of sets of the first electrode, the second electrode, and the third electrode are provided, and energization is performed so that each set starts welding in synchronization, and a plurality of objects to be welded are provided. Since the welding of the points is performed simultaneously, it is possible to eliminate the diversion of the current which has been a problem when performing welding of multiple points in the conventional resistance welding. As a result, according to the present invention, appropriate welding can be realized, and setting of welding conditions can be simplified. Further, in the present invention, since welding of a plurality of points is simultaneously performed, the number of times of welding can be reduced, and the tact time of the welding process can be improved. Further, according to the present invention, an increase in welding current associated with diversion can be eliminated, so the capacity per welding power source can be reduced. Further, in the present invention, as in the conventional resistance welding, it is possible to avoid the generation of metal powder and the breakage of an object to be joined.

  Further, in the present invention, when the resistance between the first and second electrodes, which is a physical quantity detected during welding, reaches the inter-electrode resistance value preset as the termination condition value, By performing welding of the first control method n times to stop the energization of the electrode of 2, the influence of the dirt on the electrode and the oxide film on the surface of the object to be welded can be reduced, and appropriate welding can be realized. Can.

  Further, in the present invention, by providing the suction mechanism, the back plate can be easily fixed to the surface of the third electrode opposed to the inner circumferential surface of the wound body.

  Further, in the present invention, the force required for the insertion / extraction mechanism to withdraw the third electrode from the article or the force required for withdraw the article from the first, second and third electrodes is a predetermined threshold value. By issuing an alarm in the following cases, the user can be notified that welding is inappropriate.

  Further, in the present invention, the vacuum pressure detection means detects when the inserting and removing mechanism extracts the third electrode from the object to be bonded or when the object to be bonded is extracted from the first, second, and third electrodes. By issuing an alarm when the vacuum pressure is below a predetermined threshold, the user can be notified that the welding is inappropriate.

It is a block diagram showing composition of a welding device concerning an embodiment of the invention. It is an expanded sectional view of a welding head concerning an embodiment of the invention. It is a block diagram which shows the structure of the physical quantity detection part which concerns on embodiment of this invention. It is a flow chart explaining operation of a welding device concerning an embodiment of the invention. It is a figure which shows one example of the change of the welding current during welding, welding voltage, and welding power. It is a figure which shows one example of a change of the resistance between electrodes during welding. It is a figure which shows one example of the change of the load in welding, and a displacement amount. It is a perspective view and sectional drawing of a winding type lithium ion battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a welding apparatus according to an embodiment of the present invention. The welding apparatus according to the present embodiment includes a welding power source 1-1, 1-2, a welding head 2, and a physical quantity detection unit 3-1 for detecting one or more physical quantities related to an object to be welded. 2 and vacuum pressure detection units 4-1 and 4-2 for detecting the vacuum pressure of the suction mechanism described later, a control unit 5 for controlling the entire welding apparatus, and an operation for the user to give an instruction to the welding apparatus A storage unit 7 stores a program for the control unit 5 and welding conditions in advance, and a display unit 8 for presenting information to the user.

The welding power supplies 1-1 and 1-2 supply a current between electrodes of the welding head 2 described later. About such a welding power supply, since it is indicated by JP, 2013-111588, A, for example, detailed explanation is omitted.
The control unit 5 and the display unit 8 constitute alarm notification means.

  FIG. 2 is an enlarged sectional view of the welding head 2. The welding head 2 includes an upper electrode 20-1a (first electrode), a lower electrode 20-1b (second electrode), an intermediate electrode 20-1c (third electrode), and an upper electrode 20-1a. It is equipped with pressing mechanisms 21-1a and 21-1b that sandwich and press the object 24 by raising and lowering the lower electrode 20-1b, and suction mechanisms 22-1a and 22-1b that vacuum-suck a back plate described later. ing.

  The welding head 2 also includes an upper electrode 20-2a (first electrode), a lower electrode 20-2b (second electrode), an intermediate electrode 20-2c (third electrode), and a pressing mechanism 21. 2a and 21-2b, and suction mechanisms 22-2a and 22-2b. Thus, in the present embodiment, two sets of the upper electrode, the lower electrode, and the intermediate electrode are provided. In addition, in FIG. 2, description of a vacuum pump etc. is abbreviate | omitted among the systems which comprise adsorption mechanism 22-1a, 22-1b, 22-2a, 22-2b, and only the vacuum adsorption pad is shown in figure.

  The pressure mechanisms 21-1a, 21-1b, 21-2a, 21-2b are provided with load cells (not shown) so that the magnitude of the load applied to the workpiece 24 can be converted into an electrical signal. There is. Further, displacement sensors (not shown) are provided in the pressing mechanisms 21-1a, 21-1b, 21-2a, and 21-2b, and can convert the displacement amount of the object 24 in the thickness direction into an electrical signal. It is supposed to be. The adsorption mechanisms 22-1a and 22-1b are attached to the intermediate electrode 20-1c, and the adsorption mechanisms 22-2a and 22-2b are attached to the intermediate electrode 20-2c.

  Furthermore, the welding head 2 is inserted into the inside 29 of the cylindrical winding body 25 at the start of welding, and the pipe expanding mechanism (FIG. 1 of FIG. 1) expands the tube 25 so that the winding body 25 expands in the vertical direction (the metal foil laminating direction). 40) and intermediate electrodes 20-1c and 20-2c in a state in which a back plate to be described later is vacuum-adsorbed at the start of welding are inserted into the inside 29 of the wound body 25 expanded by the pipe expansion mechanism 20-1c and 20-2c are provided from the inside 29 of the wound body 25 with an insertion and removal mechanism (41 in FIG. 1).

  Next, the article 24 according to the present embodiment will be described. The object to be bonded 24 includes a wound body 25 having a structure in which a plurality of metal foils are stacked and wound in a spiral shape, and a plate-like member made of metal disposed in contact with the outer peripheral surface of the wound body 25 The plurality of metals of the current collector 26 on which the projections 27-1a, 27-1b, 27-2a, and 27-2b, which are projections with respect to the wound body 25, are formed, and a plurality of metal sheets of the wound body 25. Back plates (hereinafter, BP) 28-1a, 28-1b, 28- which are plate-like members made of metal disposed on the inside of the wound body 25 so as to face the current collector 26 with a foil interposed therebetween. 2a and 28-2b.

  The wound body 25 corresponds to the configuration of the wound lithium ion battery in FIG. 8B as viewed from the left side or the right side. When the configuration of the wound lithium ion battery shown in FIG. 8B is viewed from the left side is a wound body 25, the metal foil constituting the wound body 25 is made of Al or an Al alloy. In this case, the current collector 26 and the BPs 28-1a, 28-1b, 28-2a, 28-2b are also made of Al or an Al alloy, and the material of the electrodes 20-1a to 20-1c, 20-2a to 20-2c is It becomes Cu alloy.

  On the other hand, when the configuration of the wound lithium ion battery shown in FIG. 8B is viewed from the right side is a wound body 25, the metal foil constituting the wound body 25 is made of Cu or a Cu alloy. In this case, the current collector 26 and the BPs 28-1a, 28-1b, 28-2a, 28-2b are also made of Cu or a Cu alloy, and the material of the electrodes 20-1a to 20-1c, 20-2a to 20-2c is The metal or alloy includes at least one element of molybdenum (Mo), tungsten (W), iron (Fe), nickel (Ni), and titanium (Ti).

  The reason why the materials of the electrodes 20-1a to 20-1c and 20-2a to 20-2c are different from the case of the Al foil is that, when the wound body 25 is made of a Cu foil, the wound body 25 generates heat even when current flows. It is because it is difficult to cause the electrodes 20-1a to 20-1c and 20-2a to 20-2c to generate heat.

  As apparent from FIG. 2, the current collector 26 is disposed so as to sandwich the wound body 25 in the vertical direction (the stacking direction of the metal foils). Projections 27-1a, 27-1b, 27-2a and 27-2b, which are projections formed in advance on the current collector 26, are wound with the electrodes 20-1a, 20-1b, 20-2a and 20-2b. 25 so as to be located between The projections 27-1a, 27-1b, 27-2a, 27-2b are formed by the number of the upper electrodes 20-1a, 20-2a and the lower electrodes 20-1b, 20-2b. In the present embodiment, since there are two upper electrodes 20-1a and 20-2a and two lower electrodes 20-1b and 20-2b, two each for the upper current collector 26 and the lower current collector 26. Projections 27-1a, 27-1b, 27-2a, 27-2b are formed. When the current collector 26 is 1 mm thick, the height of the projection 87 is about 1 mm.

  The projections 27-1a, 27-1b, 27-2a, 27-2b are formed by coining. By adopting the coining process, the surface of the current collector 26 on the opposite side to the projections 27-1a, 27-1b, 27-2a, 27-2b can be shaped without any dents, and the wound body 25 can be formed. The projections 27-1a, 27-1b, 27-2a, and 27-2b are deformed and become low when a predetermined load is applied by sandwiching the electrodes 20-1a, 20-1b, 20-2a, and 20-2b from above and below Even in this case, contact between the current collector 26 and the wound body 25 can be avoided in portions other than the projections 27-1a, 27-1b, 27-2a, and 27-2b, and the load is not limited to the projections 27. It can be made to concentrate on the contact part of -1a, 27-1b, 27-2a, 27-2b and the winding body 25 intensively.

  FIG. 3 is a block diagram showing the configuration of the physical quantity detection unit 3-1. The physical quantity detection unit 3-1 includes a current detection unit 30, a voltage detection unit 31, a power detection unit 32, a resistance detection unit 33, a load detection unit 34, and a displacement detection unit 35.

  The current detection unit 30 detects a welding current I1 flowing between the electrodes 20-1a and 20-1b from the output of a Hall element (not shown). The voltage detection unit 31 detects a welding voltage V1 applied between the electrodes 20-1a and 20-1b. Power detection unit 32 is supplied to electrodes 20-1a and 20-1b by integrating the value of welding current I1 detected by current detection unit 30 and the value of welding voltage V1 detected by voltage detection unit 31. The welding power W1 is detected.

  The resistance detection unit 33 calculates the resistance R1 between the electrodes 20-1a and 20-1b from the value of the welding voltage V1 detected by the voltage detection unit 31 and the value of the welding current I1 detected by the current detection unit 30. The load detection unit 34 detects the load G1 applied to the workpiece 24 based on the outputs of the load cells provided in the pressing mechanisms 21-1a and 21-1b. The displacement detection unit 35 detects the displacement amount D1 in the thickness direction of the workpiece 24 based on the outputs of the displacement sensors provided in the pressing mechanisms 21-1a and 21-1b.

  The configuration of the physical quantity detection unit 3-2 is the same as that of the physical quantity detection unit 3-1. The current detection unit 30 of the physical quantity detection unit 3-2 detects the welding current I2 flowing between the electrodes 20-2a and 20-2b, and the voltage detection unit 31 of the physical quantity detection unit 3-2 includes the electrodes 20-2a and 20. The welding voltage V2 applied between -2b is detected. The power detection unit 32 of the physical quantity detection unit 3-2 detects the welding power W2 supplied to the electrodes 20-2a and 20-2b, and the resistance detection unit 33 of the physical quantity detection unit 3-2 detects the welding power W2. The resistance R2 between 2a and 20-2b is calculated. Further, the load detection unit 34 of the physical quantity detection unit 3-2 detects the load G2 applied to the article 24 based on the output of the load cell provided in the pressing mechanisms 21-2a and 21-2b, The displacement detection unit 35 of the physical quantity detection unit 3-2 detects the displacement amount D2 of the object 24 in the thickness direction based on the outputs of the displacement sensors provided in the pressing mechanisms 21-2a and 21-2b. .

Hereinafter, the operation of the welding device of the present embodiment will be described. FIG. 4 is a flow chart for explaining the operation of the welding apparatus.
For example, when the user operates the operation unit 6 to instruct the start of welding, the control unit 5 controls the tube expanding mechanism 40 of the welding head 2 so that the axial direction of the wound body 25 (direction perpendicular to the sheet of FIG. 2) The tube expanding mechanism 40 is inserted into the inside 29 of the cylindrical winding body 25 along the direction of FIG. 4 so that the winding body 25 is expanded so as to expand in the vertical direction (step S1 in FIG. 4). As described above, since the wound body 25 is formed by laminating a plurality of metal foils and winding in a spiral shape, it is easy to deform the wound body 25 so as to expand in the vertical direction.

  Then, the lower surface of the BP 28-1a is vacuum-adsorbed by the adsorption mechanism 22-1a, and the upper surface of the BP 28-1b is vacuum-adsorbed by the adsorption mechanism 22-1b so that the BPs 28-1a and 28-1b can be vertically At the same time, the lower surface of BP 28-2a is vacuum-adsorbed by adsorption mechanism 22-2a, and the upper surface of BP 28-2b is vacuum-adsorbed by adsorption mechanism 22-2b, and BP28-2a and 28-2b are made of intermediate electrode 20-2c. The control unit 5 controls the insertion and removal mechanism 41 in a state of being fixed to the upper and lower sides. The insertion and removal mechanism 41 inserts the intermediate electrodes 20-1c and 20-2c along the axial direction of the wound body 25 into the inside 29 of the wound body 25 expanded by the pipe expanding mechanism 40 (step S2 in FIG. 4).

  The intermediate electrode 20-1c is aligned with the electrodes 20-1a and 20-1b in a straight line when the workpiece 24 is vertically sandwiched by the electrodes 20-1a and 20-1b. It is inserted into the inside 29. Similarly, when the workpiece 24 is sandwiched by the electrodes 20-2a and 20-2b in the vertical direction, the intermediate electrode 20-2c is wound so as to align with the electrodes 20-2a and 20-2b. It is inserted into the interior 29 of the body 25.

  Subsequently, the control unit 5 pulls the pipe expanding mechanism 40 out of the inside 29 of the wound body 25 to release the pipe expanding by the pipe expanding mechanism 40, and then pressurizing mechanisms 21-1 a, 21-1 b, and the like of the welding head 2. 21-2a and 21-2b are controlled, and the object 24 is vertically sandwiched by the electrodes 20-1a and 20-1b and pressurized, and at the same time, the object 24 is vertically oriented by the electrodes 20-2a and 20-2b. Then, sandwich and pressurize (step S3 in FIG. 4). At this time, in the current collector 26, the projections 27-1a, 27-1b, 27-2a, 27-2b of the current collector 26 are wound with the electrodes 20-1a, 20-1b, 20-2a, 20-2b. It is arranged so as to be located between the circular body 25.

  In the example shown in FIG. 2, the pressing mechanisms 21-1a, 21-1b, 21-2a, 21-2b apply pressure to the electrodes 20-1a, 20-1b, 20-2a, 20-2b, respectively. However, it goes without saying that pressure may be applied to only one of the upper electrodes 20-1a and 20-2a and the lower electrodes 20-1b and 20-2b.

  After completion of pressurization by pressurization mechanisms 21-1a, 21-1b, 21-2a, 21-2b, control unit 5 controls welding power sources 1-1, 1-2 to control welding power source 1-1 from welding power source 1-1. At the same time as supplying welding current between the electrodes 20-1a and 20-1b, welding current is supplied between the welding power source 1-2 and the electrodes 20-2a and 20-2b.

  The current supplied from welding power source 1-1 is upper electrode 20-1a, current collector 26, wound body 25, BP 28-1a, intermediate electrode 20-1c, BP 28-1b, wound body 25, current collector 26, and the lower electrode 20-1b. In addition, the current supplied from welding power source 1-2 is upper electrode 20-2a, current collector 26, wound body 25, BP28-2a, intermediate electrode 20-2c, BP28-2b, wound body 25, and collected current. The current flows in the path of the current collector 26 and the lower electrode 20-2b.

  By supplying such a welding current, the bonding surface (the bonding surface between metals) of the object 24 is melted and bonded by the generated Joule heat. In the present embodiment, the projections 27-1a and 27-1b of the current collector 26 are deformed and lowered by the pressure applied by the pressure mechanisms 21-1a and 21-1b, and the tip of the projection 27-1a, Winding body 25 at a position immediately below projection 27-1a and BP 28-1a at a position immediately below projection 27-1a are melted to join current collector 26, winding body 25 and BP 28-1a. , The tip of the projection 27-1b, the wound body 25 at a position just above the projection 27-1b, and the BP 28-1b at a position just above the projection 27-1b, 26, the wound body 25 and the BP 28-1b are joined.

  Similarly, the projections 27-2a and 27-2b are deformed and lowered by the pressure applied by the pressure mechanisms 21-2a and 21-2b, and the tip of the projection 27-2a and the position directly below the projection 27-2a The wound body 25 and the BP 28-2a at a position immediately below the projection 27-2a are melted to join the current collector 26, the wound body 25 and the BP 28-2a, and the tip of the projection 27-2b. Portion, the wound body 25 at a position directly above the projection 27-2b, and the BP 28-2b at a position directly above the projection 27-2b are melted to form the current collector 26, the wound body 25 and the BP 28- 2b is joined.

  The thickness of BP28-1a, 28-1b, 28-2a, 28-2b is such that the part in contact with wound body 25 melts in welding and the part in contact with intermediate electrodes 20-1c, 20-2c melts The thickness may be set to no thickness, for example, 1/2 or more of the thickness of the current collector 26 is appropriate.

  FIG. 5 shows an example of changes in welding current I1, welding voltage V1 and welding power W1 during welding, FIG. 6 shows an example of changes in inter-electrode resistance R1 during welding, and FIG. 7 shows during welding It is a figure which shows one example of the change of the load G1 of this, and the displacement amount D1. The horizontal axis in FIGS. 5 to 7 is time. Although only welding current I1 and welding voltage V1 indicate positive pulses in the example of FIG. 5, an AC voltage is applied to the primary side of a transformer (not shown) of welding power source 1-1. Therefore, the welding current I1 and the welding voltage V1 may be negative pulses. In addition, changes in welding current I2, welding voltage V2, welding power W2, inter-electrode resistance R2, load G2 and displacement D2 are also welding current I1, welding voltage V1, welding power W1, inter-electrode resistance R1, load G1, displacement Similar to quantity D1.

  Control unit 5 controls welding power sources 1-1, 1-2 to apply a pulse current as shown in FIG. 5 between electrodes 20-1a, 20-1b and between electrodes 20-2a, 20-2b. Monitoring the physical quantity detected during welding in real time, and stopping the operation of the welding power sources 1-1, 1-2 when the physical quantity reaches a predetermined termination condition value, and the electrodes 20-1a, 20- Energization between 1b and between the electrodes 20-2a and 20-2b is ended, and after a predetermined cooling time (for example, several msec) has elapsed from the end of the energization, the next pulse current is applied. As described above, the control unit 5 performs welding in synchronization with the combination of the electrodes 20-1a to 20-1c and the welding power supply 1-1, and the combination of the electrodes 20-2a to 20-2c and the welding power supply 1-2. Conduct energization control to start.

In the storage unit 7, desired values of physical quantities to be detected during welding are set in advance as termination condition values for each of the welding conduction pulses. As these physical quantities, there are welding current value I ₀ , welding voltage value V ₀ , inter-electrode resistance value R ₀ , load value G ₀ and displacement amount D ₀ . The user of the welding apparatus can perform a welding test for setting the termination condition value beforehand using the target object 24 and set the value of the physical quantity when the appropriate welding is obtained in the storage unit 7. Just do it.

In the present embodiment, welding is first performed by the resistance control method in which the inter-electrode resistance value _R0 preset in the storage unit 7 is used as the end condition value (step S4 in FIG. 4). Specifically, when the control unit 5 performs resistance control based on feedback of the inter-electrode resistance value, the electrodes detected by the respective resistance detection units 33 of the physical quantity detection units 3-1 and 3-2 for each energization pulse The inter-electrode resistance values R1 and R2 are monitored, and when the inter-electrode resistance value R1 reaches the inter-electrode resistance value _R0 preset in the storage unit 7, the welding power source 1-1 to the electrodes 20-1a and 20-1b to terminate the energization of the, also the inter-electrode resistance value R2 electrodes 20-2a from the welding power source 1-2 at which point the inter-electrode resistance value R _0, and terminates the energization of the 20-2b.

The control unit 5 performs resistance control type welding n times (n is an integer of 1 or more). Here, applying one pulse current as shown in FIG. 5 to the electrodes 20-1a, 20-1b, 20-2a and 20-2b is counted as one time. When the resistance control method of welding is performed a plurality of times, the end condition value is set in advance so as to change every time. For example, when the resistance control method of welding is performed twice, the inter-electrode resistance value R _{0 which} is the first end condition value and the inter-electrode resistance value R ₀₂ which is the second end condition value are such that R ₀ > R ₀₂ It is related. The reason why the end condition value decreases every time is that the inter-electrode resistance value R decreases as welding is repeated. As described above, in the case where the resistance control method of welding is performed a plurality of times, it is necessary to set an end condition value for each time. When the resistance control method of welding is performed a plurality of times, the next welding is performed after a predetermined cooling time has elapsed from the end of one welding (the end of energization).

  In the present embodiment, since two pairs of the upper electrode, the lower electrode and the intermediate electrode are provided, the pair of the upper electrode 20-1a, the lower electrode 20-1b and the intermediate electrode 20-1c, and the upper electrode 20 are provided. Among the sets of -2a, the lower electrode 20-2b, and the intermediate electrode 20-2c, there is a possibility that the inter-electrode resistance value R in any one set may reach the termination condition value first.

  For example, when the inter-electrode resistance value R1 reaches the end condition value first, the control unit 5 waits for the inter-electrode resistance value R2 to reach the end condition value, and after the inter-electrode resistance value R2 reaches the end condition value. After the predetermined cooling time has elapsed, the next welding is performed so that each pair synchronously starts welding. In addition, when the inter-electrode resistance value R2 reaches the end condition value first, it waits for the inter-electrode resistance value R1 to reach the end condition value, and a predetermined cooling time after the inter-electrode resistance value R1 reaches the end condition value. After the lapse of time, perform the next welding.

  Next, the control unit 5 completes the n control weldings (YES in step S5 in FIG. 4), and performs another control after a predetermined cooling time has elapsed from the end of the welding (when the energization is completed). Welding is performed according to the method (step S6 in FIG. 4). Also in the welding of this step S6, energization control is performed so that each group starts welding in synchronization.

As control methods other than the resistance control method, a current control method using welding current value I ₀ as an end condition value, a voltage control method using welding voltage value V ₀ as an end condition value, welding power value W ₀ as an end condition value There are a power control method to be used, a load control method using a load value G ₀ as an end condition value, and a displacement control method using a displacement amount D ₀ as an end condition value.

When the control unit 5 performs current control based on feedback of welding current, welding is detected by each of the current detection units 30 of the physical quantity detection units 3-1 and 3-2 for each energization pulse as shown in FIG. The currents I1 and I2 are monitored in real time, and when the absolute value of the welding current I1 reaches the welding current value I ₀ preset in the storage unit 7, the welding power source 1-1 to the electrodes 20-1a and 20-1b to terminate the energization of the, also the absolute value of the welding current electrode 20-2a from the welding power source 1-2 at which point I ₀ of the welding current I2, to terminate the energization of the 20-2b.

When performing voltage control based on feedback of welding voltage, control unit 5 monitors welding voltages V1 and V2 detected by voltage detection unit 31 of physical quantity detection units 3-1 and 3-2 for each energization pulse. Te, the absolute value of the electrodes 20-1a from the welding power source 1-1 at which point the welding voltage value V ₀ which is previously set in the storage unit 7 of the welding voltage V1, to terminate the energization of the 20-1b, also welding electrode 20-2a from the voltage V2 of the absolute value of the welding power source 1-2 at which point the welding voltage value V _0, to terminate the energization of the 20-2b.

When performing power control based on feedback of welding power, control unit 5 monitors welding power W1, W2 detected by power detection unit 32 of each of physical quantity detection units 3-1, 3-2 for each energization pulse. Te, welding power W1 electrodes 20-1a from the welding power source 1-1 at which point the welding power value W ₀ which is previously set in the storage unit 7 terminates the energization of the 20-1b, also welding power W2 electrodes 20-2a from the welding power source 1-2 at which point the welding power value W _0, to terminate the energization of the 20-2b.

When performing load control based on load feedback, the control unit 5 monitors the loads G1 and G2 detected by the load detection units 34 of the physical quantity detection units 3-1 and 3-2 for each energization pulse, and load G1 electrodes from the welding power source 1-1 when it reaches the load value G ₀ which is previously set in the storage unit 7 20-1a, to terminate the energization of the 20-1b, also load G2 is the load value G ₀ When it reaches, the energization from the welding power source 1-2 to the electrodes 20-2a and 20-2b is ended.

When the displacement control based on the feedback of the displacement amount is performed, the control unit 5 monitors the displacement amounts D1 and D2 detected by the displacement detection units 35 of the physical quantity detection units 3-1 and 3-2 for each energization pulse. Te, displacement D1 is preset displacement D ₀ electrode from the welding power source 1-1 at which point 20-1a in the storage unit 7 terminates the energization of the 20-1b, also the displacement amount D2 is displaced When the amount D ₀ is reached, the current supply from the welding power source 1-2 to the electrodes 20-2 a and 20-2 b is terminated.

  The control unit 5 performs m-time welding (m is an integer of 1 or more) of any control method of a current control method, a voltage control method, a power control method, a load control method, and a displacement control method. When welding of these control methods is performed a plurality of times, the end condition value may be changed every time, or a common value may be used as the end condition value of the plurality of times of welding. Also, the control method may be changed once or plural times.

  Further, as in the case of the resistance control method, when welding is performed a plurality of times, a combination of the electrodes 20-1a to 20-1c and the welding power supply 1-1, the electrodes 20-2a to 20-2c and the welding power supply 1-2 It is possible that one of the sets of physical quantities (current, voltage, power, load, displacement) reaches the end condition value first. In this case, as in the resistance control method, after the physical quantity of one set reaches the end condition value first, it waits for the physical quantity of the other set to reach the end condition value, and the physical quantity of the other set is the end condition After a predetermined cooling time has elapsed since the value has been reached, the next welding may be performed so that each set starts welding in synchronization.

  When m times of welding are completed (YES in FIG. 4 step S7), it is necessary to remove the intermediate electrodes 20-1c and 20-2c from the inside of the wound body 25. That is, the control unit 5 controls the pressing mechanisms 21-1a, 21-1b, 21-2a, 21-2b to be bonded by the electrodes 20-1a, 20-1b, 20-2a, 20-2b. After releasing the pressure applied to the H.24 (step S8 in FIG. 4), the insertion and removal mechanism 41 is controlled. The insertion and removal mechanism 41 extracts the intermediate electrodes 20-1c and 20-2c from the inside 29 of the wound body 25 along the axial direction of the wound body 25 (step S9 in FIG. 4).

  The suction mechanisms 22-1a, 22-1b, 22-2a, 22-2b vacuum-adsorb the BPs 28-1a, 28-1b, 28-2a, 28-2b until all the processing of the welding apparatus is completed. The vacuum adsorption acts as a force against the withdrawal of the intermediate electrodes 20-1c and 20-2c. Therefore, when the force required for the insertion and removal mechanism 41 to withdraw the intermediate electrodes 20-1c and 20-2c from the wound body 25 is small, the BPs 28-1a, 28-1b, 28-2a, and 28-2b are wound. There is a possibility that the coil 25 is not welded and has been detached from the wound body 25 with the intermediate electrodes 20-1c and 20-2c.

  The loading and unloading mechanism 41 is provided with a load cell (not shown), and the load cell converts the magnitude of the force necessary to withdraw the intermediate electrodes 20-1c and 20-2c from the wound body 25 into electrical signals, The output of the load cell can be notified to the control unit 5. If the force required for the insertion and removal mechanism 41 to pull out the intermediate electrodes 20-1c and 20-2c from the winding body 25 is less than a predetermined threshold (FIG. 4, step S10), the controller 5 is improper in welding. For example, the alarm message is displayed on the display unit 8 to issue an alarm (step S11 in FIG. 4).

  The vacuum pressure detection unit 4-1 detects the vacuum pressure of the adsorption mechanisms 22-1a and 22-1b, and the vacuum pressure detection unit 4-2 detects the vacuum pressure of the adsorption mechanisms 22-2a and 22-2b. If the insertion and removal mechanism 41 can properly pull out the intermediate electrodes 20-1c and 20-2c from the wound body 25, the vacuum pressure detected by the vacuum pressure detection unit 4-1, 4-2 increases (that is, the degree of vacuum decreases) To do). On the other hand, when the BPs 28-1a, 28-1b, 28-2a, 28-2b are separated from the wound body 25 together with the intermediate electrodes 20-1c, 20-2c, the vacuum pressure remains low.

Therefore, when the inserting and removing mechanism 41 withdraws the intermediate electrodes 20-1c and 20-2c from the winding body 25, the control unit 5 performs at least the vacuum pressure detected by the vacuum pressure detecting unit 4-1, 4-2. If one vacuum pressure is lower than a predetermined vacuum pressure threshold (step S12 in FIG. 4), it is determined that welding is inappropriate, and an alarm message is issued, for example, by displaying an alarm message on the display unit 8 (step S11). ).
Above, processing of a welding device is completed. The control unit 5 may cause the display unit 8 to display the waveform of the physical quantity detected during welding.

  As described above, in the present embodiment, two pairs of the upper electrode, the lower electrode, and the intermediate electrode are provided, and each pair is energized in synchronization to start welding, and two points above and below the object 24 Since the welding of a total of four points is simultaneously performed, it is possible to eliminate the diversion of the current which has become a problem when performing welding of a plurality of points in the conventional resistance welding.

  As a result, in the present embodiment, appropriate welding can be realized, and setting of welding conditions can be simplified. Further, in the present embodiment, since welding of a plurality of points is performed simultaneously, the number of times of welding can be reduced, and tact time of the welding process can be improved. Further, in the present embodiment, an increase in welding current due to the diversion can be eliminated, so the capacity per welding power source can be reduced.

  However, in order to eliminate the diversion, a set of the upper electrode 20-1a, the lower electrode 20-1b, and the intermediate electrode 20-1c, and a set of the upper electrode 20-2a, the lower electrode 20-2b, and the intermediate electrode 20-2c It is necessary to make the direction of current supply to the workpiece 24 the same. In the present embodiment, a current flows from the upper electrode 20-1a to the lower electrode 20-1b, and a current flows from the upper electrode 20-2a to the lower electrode 20-2b at the same time. The directions are the same.

  Further, in the present embodiment, after welding of the resistance control method is performed n times, welding of another control method is performed m times. In the first welding, between the electrodes 20-1a and 20-1b and the electrodes 20-2a and 20 because of contamination of the electrodes 20-1a to 20-1c and 20-2a to 20-2c and an oxide film on the surface of the object to be bonded. The current path between -2b is unstable. Therefore, in order to suppress the generation of dust, resistance control welding is performed n times to remove the dirt on the electrodes 20-1a to 20-1c and 20-2a to 20-2c and the oxide film on the surface of the object to be bonded. When the inter-electrode resistance values R1 and R2 decrease and the current passage is stabilized, welding of another control method is performed m times. Thereby, in the present embodiment, the influence of the dirt on the electrodes 20-1a to 20-1c and 20-2a to 20-2c and the oxide film on the surface of the object to be bonded can be reduced, and appropriate welding can be realized. be able to.

  Moreover, you may employ | adopt the conventional control system as a control system of welding performed by FIG.4 S6. The control method here is a constant current control method of supplying a predetermined welding current I for a fixed time, a constant voltage control method of supplying a predetermined welding voltage V for a predetermined time, constant power of supplying a predetermined welding power W for a predetermined time There is a control method etc.

  In the present embodiment, two sets of the upper electrode, the lower electrode, and the intermediate electrode are provided. However, the present invention is not limited to this, and three or more sets may be provided. For example, if three sets of the upper electrode, the lower electrode, and the intermediate electrode are provided, it is possible to simultaneously perform welding at a total of six points at the upper and lower three points of the article 24. In this case, the welding power source, the physical quantity detection unit, and the vacuum pressure detection unit need to be provided for each set.

  Further, in the present embodiment, the current collectors 26 are disposed above and below the wound body 25, but the current collectors 26 are disposed only on either the upper side or the lower side of the wound body 25. May be The BP is disposed to face the current collector 26 with the plurality of metal foils of the wound body 25 interposed therebetween, so that the current collector 26 is provided on the upper or lower side of the wound body 25. The BP will be placed only on the side. Further, when the current collector 26 is disposed only on either the upper side or the lower side of the wound body 25, the upper electrode or the lower electrode and the outer peripheral surface of the wound body 25 are not provided on the side where the current collector 26 is not disposed. Are in direct contact with each other, and the intermediate electrode and the inner circumferential surface of the winding body 25 are in direct contact with each other.

  When the current collectors 26 are disposed on only one of the upper side and the lower side of the wound body 25 as compared with the case where the current collectors 26 are disposed on the upper and lower sides of the wound body 25, Although it is reduced, in the case where two sets of the upper electrode, the lower electrode and the middle electrode are provided, the welding can be performed simultaneously in the case where the two sets of the upper electrode, the lower electrode and the middle electrode are provided simultaneously It is.

  Further, in the present embodiment, the intermediate electrodes 20-1c and 20-2c are inserted into the inside 29 of the wound body 25 in step S2, and the intermediate electrodes 20-1c and 20-2c are inserted in the wound body 25 in step S9. Although it pulls out from internal part 29, it does not restrict to this, and insertion and removal mechanism 41 may carry out insertion and removal of article 24 to and from an electrode.

  In this case, the insertion and removal mechanism 41 is adsorbed by the adsorption mechanism 22-1b of the intermediate electrode 20-1c between the BP 28-1a adsorbed by the adsorption mechanism 22-1a of the intermediate electrode 20-1c and the upper electrode 20-1a. Between the BP 28-1b and the lower electrode 20-1b, the BP 28-2a adsorbed by the adsorption mechanism 22-2a of the intermediate electrode 20-2c, and the upper electrode 20-2a, and the intermediate electrode 20-2c. The winding body 25 and the current collector 26 may be inserted along the axial direction of the winding body 25 between the BP 28-2 b adsorbed by the adsorption mechanism 22-2 b and the lower electrode 20-2 b (step S2).

  In addition, the insertion and removal mechanism 41 includes the workpiece 24 in which the wound body 25, the current collector 26, and the BPs 28-1a, 28-1b, 28-2a, and 28-2b are welded in the axial direction of the wound body 25. The electrodes 20-1a to 20-1c and 20-2a to 20-2c may be drawn along (step S9).

In the present embodiment, the vacuum suction pads of the suction mechanisms 22-1a, 22-1b, 22-2a, 22-2b are provided around the intermediate electrodes 20-1c, 20-2c, but the intermediate electrodes 20-1c are provided. 20-2c itself may be provided with a suction nozzle.
Further, in the present embodiment, a wound lithium ion battery is described as an example of the wound body 25. However, the present invention can be applied to other wound bodies.

  The functions of the control unit 5, the operation unit 6, the storage unit 7 and the display unit 8 according to the present embodiment include a CPU (Central Processing Unit), a computer provided with a storage device and an interface with the outside, and hardware resources thereof. It can be realized by a program to control. The CPU executes the processing described in the present embodiment in accordance with the program stored in the storage device.

  The present invention can be applied to a technique of welding a plurality of points to a wound body such as a wound lithium ion battery.

  1-1, 1-2 ... welding power source, 2 ... welding head, 3-1, 3-2 ... physical quantity detection unit, 4-1, 4-2 ... vacuum pressure detection unit, 5 ... control unit, 6 ... operation unit , 7 storage unit, 8 display unit, 20-1a, 20-2a upper electrode, 20-1b, 20-2b lower electrode, 20-1c, 20-2c intermediate electrode, 21-1a, 21- 1b, 21-2a, 21-2b ... pressurization mechanism, 22-1a, 22-1b, 22-2a, 22-2b ... adsorption mechanism, 24 ... bonded object, 25 ... wound body, 26 ... current collector 27-1a, 27-1b, 27-2a, 27-2b ... projection, 28-1a, 28-1b, 28-2a, 28-2b ... back plate, 30 ... current detection unit, 31 ... voltage detection unit, 32: power detection unit, 33: resistance detection unit, 34: load detection unit, 35: displacement detection unit, 40: tube expansion mechanism 41 ... insertion and removal mechanism.

Claims (8)

A wound body having a structure in which a plurality of metal foils are stacked and wound in a spiral shape, and a plate-like member made of metal disposed so as to be in contact with the outer peripheral surface of the wound body The current collector on which the convex projection is formed, and the metal disposed on the inside of the wound body so as to face the current collector with the plurality of metal foils of the wound body interposed therebetween. And a plurality of first members arranged along the laminating direction of the metal foil so as to face each other with the object to be joined interposed therebetween. , The second electrode,
It is provided for each set of the first and second electrodes inside the wound body, and at least one of two surfaces facing the inner peripheral surface of the wound body sandwich the back plate. A plurality of third electrodes arranged in line with the first and second electrodes;
A pressure mechanism that applies pressure to at least one of the first and second electrodes and causes the object to be bonded to be held between the first and second electrodes;
A plurality of welding power sources provided for each set of the first and second electrodes and supplying current between the corresponding first and second electrodes;
Physical quantity detection means for detecting one or more physical quantities of the object to be welded during welding;
An electric current is supplied from the plurality of welding power sources to the plurality of sets of first and second electrodes so that each set synchronously starts welding, and one of the physical quantities detected during welding has a predetermined termination condition. Control means for stopping energization of the first and second electrodes when the value is reached,
The welding apparatus characterized in that the plurality of welding power sources supply current to the plurality of first and second electrodes such that the current supply direction to the workpiece is the same. In the welding apparatus according to claim 1,
The control means is a physical quantity detected during welding when the resistance between the first and second electrodes reaches an inter-electrode resistance value preset as a termination condition value. After n weldings of the first control method for stopping energization of the second electrode (n is an integer of 1 or more), m welding of the second control method different from the first control method is performed m A welding apparatus characterized in that it is carried out once (m is an integer of 1 or more). In the welding apparatus according to claim 2,
The welding of the second control method is a welding that stops the energization of the first and second electrodes when the physical quantity other than the inter-electrode resistance detected during welding reaches a predetermined termination condition value. ,
The physical quantities other than the inter-electrode resistance are supplied to the welding current flowing through the first and second electrodes, the welding voltage applied between the first and second electrodes, and the first and second electrodes. A welding apparatus characterized by any one of a welding power, a load applied to the workpiece, and a displacement in a thickness direction of the workpiece. In the welding apparatus according to claim 2,
In the welding of the second control method, welding of a constant current control method for supplying a predetermined welding current to the first and second electrodes for a fixed time, and a predetermined welding voltage between the first and second electrodes A welding apparatus characterized in that it is either a constant voltage control type welding which supplies for a fixed time, or a constant power control type welding which supplies a predetermined welding power to the first and second electrodes for a fixed time. The welding apparatus according to any one of claims 1 to 4.
The control means, when welding is performed a plurality of times, waits for the welding of the slowest one of the plurality of sets of first and second electrodes to finish, and then the sets are synchronized to start welding. As described above, a welding apparatus is characterized in that the following welding is performed by supplying current from the plurality of welding power sources to the plurality of first and second electrodes. The welding apparatus according to any one of claims 1 to 5,
Furthermore, the welding apparatus is characterized by comprising an adsorption mechanism for vacuum-adsorbing the back plate and fixing the back plate to the surface of the third electrode opposed to the inner circumferential surface of the wound body. In the welding device according to claim 6,
Furthermore, after completion of welding, the third electrode is pulled out from the article along the axial direction of the wound body, or the first, second, third, or the like along the axial direction of the wound body. An insertion / extraction mechanism for pulling out the object from the electrode of
The force required to pull the third electrode from the article or the force required to draw the article from the first, second, and third electrodes is equal to or less than a predetermined threshold value. A welding apparatus comprising: alarm notification means for emitting an alarm in the case of. In the welding device according to claim 6,
Furthermore, after completion of welding, the third electrode is pulled out from the article along the axial direction of the wound body, or the first, second, third, or the like along the axial direction of the wound body. An insertion / extraction mechanism for pulling out the object from the electrode of
Vacuum pressure detection means for detecting the vacuum pressure of the suction mechanism;
The vacuum pressure detection means detects when the insertion / extraction mechanism extracts the third electrode from the object to be bonded, or when the object to be bonded is extracted from the first, second, and third electrodes. A welding apparatus comprising alarm notification means for emitting an alarm when the vacuum pressure is below a predetermined threshold.

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