JP2017030042A - Welding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately perform welding even in welding a plurality of points of a wound body.SOLUTION: A welding device includes: upper electrodes 20-1a, 20-2a, and lower electrodes 20-1b, 20-2b which are arranged with a joining object 24, which is structured of a wound body 25, a collector 26, and back plates 28-1a, 28-1b, 28-2a, 28-2b, interposed therebetween; intermediate electrodes 20-1c, 20-2c arranged inside the wound body 25; a welding power source for supplying a current between the electrodes 20-1a and 20-1b, and between the electrodes 20-2a and 20-2b; a physical quantity detection part for detecting a physical quantity relating to the joining object 24 during welding; and a control part which makes the welding power source supply the current to the electrodes 20-1a, 20-1b, 20-2a, 20-2b so that the respective pairs start welding synchronously, and makes the welding power source stop electric conduction when the physical quantity detected during the welding reaches a termination condition.SELECTED DRAWING: Figure 2

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 plate-like positive electrode and negative electrode are stacked via a separator and wound as shown in FIG. 8A has come to be used. Yes. In FIG. 8A, 100 is a positive electrode, 101 is a negative electrode, and 102 is a separator. The positive electrode 100 is an aluminum (Al) foil coated with a lithium-based material, and the negative electrode 101 is a copper (Cu) foil coated with a carbon-based material.

  FIG. 8B shows a cross-sectional structure of the cylindrical wound lithium ion battery shown in FIG. 8A cut along the XZ plane including the central axis of the cylinder. At one end of the wound lithium ion battery, there is a region in which only the Al foil of the positive electrode 100 is laminated, and a 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 where only the Cu foil of the negative electrode 101 is laminated, and the collector 104 for external connection is welded to the laminated Cu foil. The

  Usually, ultrasonic welding, laser welding, and resistance welding are used for welding the Al foil of the positive electrode 100 and the current collector 103 and welding the Cu foil of the negative electrode 101 and the current collector 104 (patent). Reference 1 and Patent Reference 2). Ultrasonic welding is a method of joining by applying ultrasonic vibration parallel to the joining surface while applying a vertical pressure to the workpieces. Laser welding is a method in which a workpiece is irradiated with laser light to be melted and joined. Resistance welding is a method of joining by joining an object to be joined between a pair of electrodes from above and below, passing an electric current between the electrodes, and melting the object to be joined by Joule heat generated.

JP 2008-66170 A JP 2009-32670 A

Ultrasonic welding has a problem in that fine metal powder drops from the battery due to ultrasonic vibration during welding. Further, when the number of Al foils or Cu foils increases, the required welding energy increases, so it is necessary to increase the output of ultrasonic waves, and there is a possibility that the Al foil or Cu foil may be torn or cut.
Laser welding has a problem in that high energy laser light is required because of the high reflectivity of Al and Cu. In addition, there is a problem that metal powder called sputtering is generated.

  On the other hand, in resistance welding, generation | occurrence | production of the metal powder and foil damage which are problems in ultrasonic welding and laser welding can be suppressed. However, in welding of the Al foil of the positive electrode 100 and the current collector 103 and welding of the Cu foil of the negative electrode 101 and the current collector 104, it is necessary to perform welding at a plurality of points for reasons such as securing welding strength. is there.

However, in resistance welding, when welding one point at a time, the current is diverted to the already welded points during the second and subsequent welding, so the current flowing to the welding electrode is increased by this diverted amount. Therefore, there is a problem that energy required for obtaining a good nugget (joint part) increases. In addition, there is a problem that the condition setting for obtaining a good quality nugget becomes complicated.
The above problems are not limited to the lithium ion battery, and similarly occur when a plurality of points are welded to a laminate of a plurality of Al foils or Cu foils.

  The present invention has been made in order to solve the above-described problem, and a welding apparatus capable of realizing appropriate welding even when a plurality of points are welded to a wound body such as a wound lithium ion battery. The purpose is to provide.

  The welding apparatus of the present invention includes a wound body having a structure in which a plurality of metal foils are laminated 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. Thus, the current collector in which a convex projection is formed with respect to the wound body, and the wound body so as to face the current collector with a plurality of metal foils sandwiched therebetween Arranged along the stacking direction of the metal foils so as to be opposed to each other with the object to be bonded interposed between the object to be bonded and the plate-shaped back plate made of metal disposed inside A plurality of sets of first and second electrodes and two sets of first and second electrodes provided in each set of the first and second electrodes inside the wound body and facing the inner peripheral surface of the wound body. The first and second electrodes are aligned with at least one of the surfaces sandwiching the back plate. A plurality of third electrodes that are arranged like a pressurization, and a pressurizing mechanism that pressurizes at least one of the first and second electrodes and clamps the object to be joined by the first and second electrodes; A plurality of welding power sources that are provided for each set of the first and second electrodes and supply current between the corresponding first and second electrodes, and one or more of the workpieces that are being welded. A physical quantity detecting means for detecting a physical quantity and a current supplied from the plurality of welding power sources to the first and second electrodes of the plurality of sets so that the respective groups start welding in synchronization are detected during welding. Control means for stopping energization of the first and second electrodes when one of the physical quantities reaches a predetermined end condition value, and the plurality of welding power sources have an energization direction to the workpiece. Supplying current to the plurality of sets of first and second electrodes so as to be the same. It is an feature.

Moreover, in one structural example of the welding apparatus of this invention, the said control means has preset the resistance between the said 1st, 2nd electrodes which is a physical quantity detected during welding as an end condition value. After the first control method of welding to stop energization of the first and second electrodes when the inter-electrode resistance value is reached, n is performed (n is an integer of 1 or more), and then the first The second control method, which is different from the control method, is welded m times (m is an integer of 1 or more).
Further, in one configuration example of the welding apparatus of the present invention, the second control method welding is performed when the physical quantity other than the interelectrode resistance detected during welding reaches a predetermined end condition value. The welding is to stop energization to the second electrode, and the physical quantity other than the interelectrode resistance is a welding current flowing through the first and second electrodes, and welding applied between the first and second electrodes. Any one of a voltage, welding power supplied to the first and second electrodes, a load applied to the workpiece, and a displacement amount in the thickness direction of the workpiece.
Further, in one configuration example of the welding apparatus of the present invention, the second control method welding is a constant current control type welding in which a predetermined welding current is supplied to the first and second electrodes for a certain period of time. 1. Constant voltage control type welding for supplying a predetermined welding voltage between the second electrodes for a certain period of time, or constant power control type welding for supplying a predetermined welding power to the first and second electrodes for a certain period of time. It is.
Further, in one configuration example of the welding apparatus of the present invention, the control means waits for the slowest welding of the plurality of sets of first and second electrodes to be completed when welding is performed a plurality of times. Then, the next welding is performed by supplying current from the plurality of welding power sources to the plurality of first and second electrodes so that each group starts welding in synchronization. is there.

Moreover, one structural example of the welding apparatus of this invention is further equipped with the adsorption | suction mechanism which vacuum-sucks the said backplate and fixes to the surface of the said 3rd electrode facing the internal peripheral surface of the said winding body. It is characterized by.
In addition, according to one configuration example of the welding apparatus of the present invention, the third electrode may be pulled out from the article to be joined along the axial direction of the wound body after the end of welding, or the shaft of the wound body An insertion / extraction mechanism for extracting the object to be bonded from the first, second, and third electrodes along a direction, and a force required for the insertion / extraction mechanism to extract the third electrode from the object to be bonded, or the first It is characterized by comprising alarm notification means for issuing an alarm when the force required for pulling out the object to be joined from the first, second and third electrodes is below a predetermined threshold value.
In addition, according to one configuration example of the welding apparatus of the present invention, the third electrode may be pulled out from the article to be joined along the axial direction of the wound body after the end of welding, or the shaft of the wound body An insertion / extraction mechanism for extracting the object to be bonded from the first, second, and third electrodes along a direction, a vacuum pressure detecting means for detecting a vacuum pressure of the adsorption mechanism, and the insertion / extraction mechanism from the object to be bonded When the vacuum pressure detected by the vacuum pressure detecting means when the third electrode is pulled out or when the workpiece is pulled out from the first, second and third electrodes is below a predetermined threshold value And an alarm notification means for issuing an alarm.

  According to the present invention, a plurality of sets of the first electrode, the second electrode, and the third electrode are provided, energization is performed so that each set starts welding in synchronization, and a plurality of sets are applied to the objects to be joined. Since spot welding is performed at the same time, it is possible to eliminate the shunting of current that has become a problem when performing welding at a plurality of points in conventional resistance welding. As a result, in the present invention, appropriate welding can be realized, and setting of welding conditions can be simplified. Moreover, in this invention, since welding of several points is performed simultaneously, the frequency | count of welding can be reduced and the tact time of a welding process can be aimed at. Further, in the present invention, it is possible to eliminate an increase in welding current due to the diversion, and therefore it is possible to reduce the capacity per welding power source. Moreover, in this invention, generation | occurrence | production of metal powder and damage to a to-be-joined object can be avoided like the conventional resistance welding.

  In the present invention, when the resistance between the first and second electrodes, which is a physical quantity detected during welding, reaches a resistance value between electrodes set in advance as an end condition value, the first and first electrodes By performing welding of the first control method for stopping energization of the second electrode n times, it is possible to reduce the influence of electrode contamination and the oxide film on the surface of the object to be bonded, and realize appropriate welding. Can do.

  Moreover, in this invention, a back plate can be easily fixed to the surface of the 3rd electrode which opposes the internal peripheral surface of a winding body by providing an adsorption | suction mechanism.

  In the present invention, the force required for the insertion / extraction mechanism to pull out the third electrode from the workpiece or the force required to pull out the workpiece from the first, second, and third electrodes is a predetermined threshold value. In the following cases, it is possible to notify the user that welding is inappropriate by issuing an alarm.

  Further, in the present invention, when the insertion / extraction mechanism pulls out the third electrode from the workpiece, or when the workpiece is pulled out from the first, second and third electrodes, the vacuum pressure detecting means detects When the vacuum pressure is less than or equal to a predetermined threshold, a warning can be issued to notify the user that welding is inappropriate.

It is a block diagram which shows the structure of the welding apparatus which concerns on embodiment of this invention. It is an expanded sectional view of the 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 flowchart explaining operation | movement of the welding apparatus which concerns on embodiment of this invention. It is a figure which shows one example of the change of the welding current in welding, welding voltage, and welding electric power. It is a figure which shows one example of the change of the resistance between electrodes during welding. It is a figure which shows one example of the load in welding, and the change of a displacement amount. It is the 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 a configuration of a welding apparatus according to an embodiment of the present invention. The welding apparatus according to the present embodiment includes welding power sources 1-1 and 1-2, a welding head 2, and physical quantity detection units 3-1 and 3- that detect one or more physical quantities relating to an object to be joined. 2, vacuum pressure detectors 4-1 and 4-2 for detecting the vacuum pressure of the suction mechanism, which will be described later, a control unit 5 for controlling the entire welding apparatus, and an operation for the user to give instructions to the welding apparatus A storage unit 7 for storing 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 sources 1-1 and 1-2 supply current between electrodes (described later) of the welding head 2. Since such a welding power source is disclosed in, for example, Japanese Patent Application Laid-Open No. 2013-111588, detailed description thereof is omitted.
The control unit 5 and the display unit 8 constitute an alarm notification unit.

  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. Pressurization mechanisms 21-1a and 21-1b that sandwich and pressurize the workpiece 24 by moving the lower electrode 20-1b up and down, and suction mechanisms 22-1a and 22-1b that vacuum-suck a back plate to be described later are provided. ing.

  The welding head 2 includes an upper electrode 20-2a (first electrode), a lower electrode 20-2b (second electrode), an intermediate electrode 20-2c (third electrode), and a pressurizing mechanism 21. -2a, 21-2b and adsorption mechanisms 22-2a, 22-2b. Thus, in this embodiment, two sets of the upper electrode, the lower electrode, and the intermediate electrode are provided. In FIG. 2, the description of the vacuum pump and the like is omitted in the system constituting the suction mechanisms 22-1a, 22-1b, 22-2a, and 22-2b, and only the vacuum suction pad is illustrated.

  The pressurizing 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 object 24 can be converted into electric signals. Yes. Moreover, the pressurization mechanisms 21-1a, 21-1b, 21-2a, 21-2b are provided with displacement sensors (not shown), and can convert the displacement amount in the thickness direction of the workpiece 24 into an electric signal. It is like that. 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 wound body 25 at the start of welding, and a tube expansion mechanism (in FIG. 1) that expands the tube so that the wound body 25 expands in the vertical direction (metal foil stacking direction). 40) and intermediate electrodes 20-1c and 20-2c in a state where a back plate, which will be described later, is vacuum-adsorbed at the start of welding, is inserted into the inside 29 of the wound body 25 expanded by the tube expansion mechanism. An insertion / extraction mechanism (41 in FIG. 1) for extracting 20-1c and 20-2c from the inside 29 of the wound body 25 is provided.

  Next, the workpiece 24 of this 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-shaped member made of metal disposed so as to be in contact with the outer peripheral surface of the wound body 25. Thus, the current collector 26 on which the projections 27-1a, 27-1b, 27-2a, and 27-2b, which are projections that are convex with respect to the wound body 25, and the plurality of metals of the wound body 25 are formed. Back plates (hereinafter referred to as BP) 28-1a, 28-1b, 28-, which are plate members made of metal disposed inside the wound body 25 so as to face the current collector 26 with a foil interposed therebetween. 2a, 28-2b.

  The wound body 25 corresponds to a configuration in which the wound lithium ion battery in FIG. 8B is viewed from the left side or the right side. If the configuration of the wound lithium ion battery of FIG. 8B 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, and 28-2b are also made of Al or an Al alloy, and the materials of the electrodes 20-1a to 20-1c and 20-2a to 20-2c are Cu alloy is formed.

  On the other hand, if the structure which looked at the winding type lithium ion battery of FIG.8 (B) from the right side is made into the wound body 25, the metal foil which comprises the wound body 25 will consist of Cu or Cu alloy. In this case, the current collector 26 and the BP 28-1a, 28-1b, 28-2a, 28-2b are also made of Cu or Cu alloy, and the materials of the electrodes 20-1a to 20-1c and 20-2a to 20-2c are A metal or alloy containing at least one element of molybdenum (Mo), tungsten (W), iron (Fe), nickel (Ni), and titanium (Ti) is obtained.

  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 Cu foil, the wound body 25 generates heat even when an electric current is passed. This is because the electrodes 20-1a to 20-1c and 20-2a to 20-2c need to generate heat.

  As is clear from FIG. 2, the current collector 26 is disposed so as to sandwich the wound body 25 from the vertical direction (the metal foil stacking direction). Projections 27-1a, 27-1b, 27-2a, and 27-2b, which are projections formed in advance on the current collector 26, are electrodes 20-1a, 20-1b, 20-2a, and 20-2b and wound bodies. 25 to be located between. The projections 27-1a, 27-1b, 27-2a, and 27-2b are formed as many as the upper electrodes 20-1a and 20-2a and the lower electrodes 20-1b and 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 of the upper current collector 26 and the lower current collector 26. Projections 27-1a, 27-1b, 27-2a, and 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, and 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 formed into a shape having no dent, When a predetermined load is applied between the electrodes 20-1a, 20-1b, 20-2a, and 20-2b, the projections 27-1a, 27-1b, 27-2a, and 27-2b are deformed and lowered. Even in this case, it is possible to avoid the current collector 26 and the wound body 25 from coming into contact with each other in the portions other than the projections 27-1a, 27-1b, 27-2a, and 27-2b. -1a, 27-1b, 27-2a, 27-2b and the contact portion between the wound body 25 can be concentrated.

  FIG. 3 is a block diagram illustrating a 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 detector 31 detects a welding voltage V1 applied between the electrodes 20-1a and 20-1b. The power detection unit 32 integrates the value of the welding current I1 detected by the current detection unit 30 and the value of the welding voltage V1 detected by the voltage detection unit 31 to be supplied to the electrodes 20-1a and 20-1b. Welding power W1 is detected.

  The resistance detector 33 calculates a resistance R1 between the electrodes 20-1a and 20-1b from the value of the welding voltage V1 detected by the voltage detector 31 and the value of the welding current I1 detected by the current detector 30. The load detection unit 34 detects the load G1 applied to the workpiece 24 based on the output of the load cell provided in the pressurization mechanisms 21-1a and 21-1b. The displacement detector 35 detects the displacement amount D1 in the thickness direction of the workpiece 24 based on the output of the displacement sensor provided in the pressurizing mechanisms 21-1a, 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 detects the electrodes 20-2a and 20-2. -B is applied to the welding voltage V2. 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 includes the electrode 20-. The resistance R2 between 2a and 20-2b is calculated. The load detector 34 of the physical quantity detector 3-2 detects the load G2 applied to the workpiece 24 based on the output of the load cell provided in the pressurizing mechanisms 21-2a and 21-2b. The displacement detector 35 of the physical quantity detector 3-2 detects the displacement D2 in the thickness direction of the workpiece 24 based on the output of the displacement sensor provided in the pressurizing mechanisms 21-2a and 21-2b. .

Hereinafter, the operation of the welding apparatus of the present embodiment will be described. FIG. 4 is a flowchart 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 expansion mechanism 40 of the welding head 2 to axially move the wound body 25 (direction perpendicular to the paper surface of FIG. 2). The tube expanding mechanism 40 is inserted into the inside 29 of the cylindrical wound body 25 along the tube so that the wound body 25 expands 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 wound 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 BP28-1a is vacuum-sucked by the suction mechanism 22-1a, and the upper surface of BP28-1b is vacuum-sucked by the suction mechanism 22-1b to place BP28-1a and 28-1b above and below the intermediate electrode 20-1c. At the same time, the lower surface of BP28-2a is vacuum-sucked by the suction mechanism 22-2a and the upper surface of BP28-2b is vacuum-sucked by the suction mechanism 22-2b to attach BP28-2a and 28-2b to the intermediate electrode 20-2c. The control part 5 controls the insertion / extraction mechanism 41 in the state fixed up and down. The insertion / extraction 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 tube expansion mechanism 40 (step S2 in FIG. 4).

  The intermediate electrode 20-1c is formed of the wound body 25 so as to be aligned with the electrodes 20-1a and 20-1b when the workpiece 24 is sandwiched between the electrodes 20-1a and 20-1b from above and below. Inserted into the interior 29. Similarly, the intermediate electrode 20-2c is wound so as to be aligned with the electrodes 20-2a and 20-2b when the workpiece 24 is sandwiched from above and below by the electrodes 20-2a and 20-2b. It is inserted into the inside 29 of the body 25.

  Subsequently, the control unit 5 removes the pipe expansion mechanism 40 from the inside 29 of the wound body 25 to release the pipe expansion by the pipe expansion mechanism 40, and then pressurizes the pressurization mechanisms 21-1a, 21-1b, 21-2a and 21-2b are controlled, and the workpiece 24 is sandwiched and pressurized from the vertical direction by the electrodes 20-1a and 20-1b. At the same time, the workpiece 24 is vertically moved by the electrodes 20-2a and 20-2b. And then pressurizing (step S3 in FIG. 4). At this time, the current collector 26 is formed by winding the projections 27-1a, 27-1b, 27-2a, and 27-2b of the current collector 26 with the electrodes 20-1a, 20-1b, 20-2a, and 20-2b. It arrange | positions so that it may be located between the rotation bodies 25.

  In the example of FIG. 2, the pressurizing 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 only to one of the upper electrodes 20-1a, 20-2a and the lower electrodes 20-1b, 20-2b.

  After the pressurization by the pressurizing mechanisms 21-1a, 21-1b, 21-2a, 21-2b is completed, the control unit 5 controls the welding power sources 1-1 and 1-2 to start from the welding power source 1-1. A welding current is supplied between the electrodes 20-1a and 20-1b and simultaneously, a welding current is supplied from the welding power source 1-2 to the electrodes 20-2a and 20-2b.

  The current supplied from the welding power source 1-1 includes the upper electrode 20-1a, the current collector 26, the wound body 25, BP28-1a, the intermediate electrode 20-1c, BP28-1b, the wound body 25, and the current collector. 26 and the lower electrode 20-1b. Further, the current supplied from the welding power source 1-2 includes the upper electrode 20-2a, the current collector 26, the wound body 25, BP28-2a, the intermediate electrode 20-2c, BP28-2b, the wound body 25, and the current collector. It flows through a path of the electric body 26 and the lower electrode 20-2b.

  By supplying such a welding current, the joining surface (joint surface between the metals) of the workpiece 24 is melted and joined 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 pressurization by the pressurizing mechanisms 21-1a and 21-1b, and the leading end of the projection 27-1a, The wound body 25 at a position directly below the projection 27-1a and the BP28-1a at a position directly below the projection 27-1a are melted, and the current collector 26, the wound body 25, and BP28-1a are joined. At the same time, the tip of the projection 27-1b, the wound body 25 at a position directly above the projection 27-1b, and the BP 28-1b at a position directly above the projection 27-1b are melted to collect a current collector. 26, the wound body 25, and BP28-1b are joined.

  Similarly, the projections 27-2a and 27-2b are deformed and lowered by the pressurization by the pressurizing mechanisms 21-2a and 21-2b, so that the tip of the projection 27-2a and the position just below the projection 27-2a are located. The wound body 25 and the BP 28-2a 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. Part, 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, and the current collector 26, the wound body 25, and the BP 28- 2b is joined.

  In addition, the thickness of BP28-1a, 28-1b, 28-2a, 28-2b melt | dissolves the part which contact | connects the winding body 25 in the case of welding, and the part which contact | connects intermediate electrode 20-1c, 20-2c. The thickness may be set to a thickness that is not, for example, ½ or more of the thickness of the current collector 26 is appropriate.

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

  The control unit 5 controls the welding power sources 1-1 and 1-2 to apply a pulse current as shown in FIG. 5 between the electrodes 20-1a and 20-1b and between the electrodes 20-2a and 20-2b. The physical quantity detected during welding is monitored in real time, and when the physical quantity reaches a predetermined end condition value, the operation of the welding power sources 1-1 and 1-2 is stopped, and the electrodes 20-1a and 20- The energization between 1b and between the electrodes 20-2a and 20-2b is terminated, 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 which the set of the electrodes 20-1a to 20-1c and the welding power source 1-1 and the set of the electrodes 20-2a to 20-2c and the welding power source 1-2 are synchronized. Energization control is performed to start.

In the storage unit 7, a desirable value of a physical quantity detected during welding is set in advance as an end condition value for each energization pulse of welding. These physical quantities include a welding current value I ₀ , a welding voltage value V ₀ , an interelectrode resistance value R ₀ , a load value G ₀ , and a displacement amount D ₀ . The user of the welding apparatus can perform a welding test for setting an end condition value using the object to be joined 24 in advance, and set a physical quantity value when appropriate welding is obtained in the storage unit 7. That's fine.

In the present embodiment, welding is first performed by a resistance control method using an interelectrode resistance value R ₀ preset in the storage unit 7 as an end condition value (step S4 in FIG. 4). Specifically, when the control unit 5 performs resistance control based on feedback of the interelectrode 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 R ₀ preset in the storage unit 7, the welding power source 1-1 supplies the electrodes 20-1a and 20-1b. When the inter-electrode resistance value R2 reaches the inter-electrode resistance value R ₀ , the energization from the welding power source 1-2 to the electrodes 20-2a and 20-2b is terminated.

The control unit 5 performs resistance control type welding n times (n is an integer of 1 or more). Here, the application of 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 performing resistance control type welding a plurality of times, it is set in advance so that the end condition value changes every time. For example, when resistance-control welding is performed twice, the interelectrode resistance value R _{0 that} is the first end condition value and the interelectrode resistance value R ₀₂ that is the second end condition value are R ₀ > R ₀₂ . There is a relationship. The reason why the end condition value decreases every time is that the inter-electrode resistance value R decreases each time welding is repeated. Thus, when performing resistance control type welding a plurality of times, it is necessary to set an end condition value for each time. When performing resistance control welding a plurality of times, the next welding is performed after a predetermined cooling time has elapsed since the end of one welding (at the end of energization).

  In the present embodiment, since two sets of the upper electrode, the lower electrode, and the intermediate electrode are provided, the set of the upper electrode 20-1a, the lower electrode 20-1b, the intermediate electrode 20-1c, and the upper electrode 20 are provided. −2a, the lower electrode 20-2b, and the intermediate electrode 20-2c, the inter-electrode resistance value R of either set may reach the end condition value first.

  For example, when the interelectrode resistance value R1 reaches the end condition value first, the control unit 5 waits for the interelectrode resistance value R2 to reach the end condition value, and after the interelectrode resistance value R2 reaches the end condition value. After a predetermined cooling time has elapsed, the next welding is performed so that the respective groups start welding in synchronization. Further, when the interelectrode resistance value R2 reaches the end condition value first, it waits for the interelectrode resistance value R1 to reach the end condition value, and a predetermined cooling time after the interelectrode resistance value R1 reaches the end condition value. After elapse of time, the next welding is performed.

  Next, the control unit 5 finishes the resistance control method n times (YES in step S5 in FIG. 4), and after the predetermined cooling time has elapsed from the end of the welding (at the end of energization), performs another control. Welding is performed by the method (step S6 in FIG. 4). Also in the welding in step S6, energization control is performed so that the respective groups start welding in synchronization.

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

When the control unit 5 performs current control based on feedback of the welding current, the welding detected by the current detection units 30 of the physical quantity detection units 3-1 and 3-2 for each energization pulse as illustrated in FIG. monitoring the currents I1, I2 in real time, welding current I1 of the absolute value previously set welding current value I ₀ electrode from the welding power source 1-1 at which point 20-1a in the storage unit 7, 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 the voltage control based on the feedback of the welding voltage is performed, the control unit 5 monitors the welding voltages V1 and V2 detected by the voltage detection units 31 of the physical quantity detection units 3-1 and 3-2 for each energization pulse. When the absolute value of the welding voltage V1 reaches the welding voltage value V ₀ preset in the storage unit 7, the energization from the welding power source 1-1 to the electrodes 20-1a and 20-1b is terminated, and the welding is performed. When the absolute value of the voltage V2 reaches the welding voltage value V ₀ , energization from the welding power source 1-2 to the electrodes 20-2a and 20-2b is terminated.

When the power control based on the feedback of the welding power is performed, the control unit 5 monitors the welding powers W1 and W2 detected by the respective power detection units 32 of the physical quantity detection units 3-1 and 3-2 for each energization pulse. When the welding power W1 reaches the welding power value W ₀ preset in the storage unit 7, the energization from the welding power source 1-1 to the electrodes 20-1a and 20-1b is terminated, and the welding power W2 is 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, When the load G1 reaches the load value G ₀ preset in the storage unit 7, the energization from the welding power source 1-1 to the electrodes 20-1a and 20-1b is terminated, and the load G2 reaches 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 terminated.

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

  The control unit 5 performs welding of a control method of any one of a current control method, a voltage control method, a power control method, a load control method, and a displacement control method m times (m is an integer of 1 or more). 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 for a plurality of times of welding. Further, the control method may be changed every time or every plural times.

  Similarly to the resistance control method, when welding is performed a plurality of times, a set of electrodes 20-1a to 20-1c and a welding power source 1-1, electrodes 20-2a to 20-2c, and a welding power source 1-2. There is a possibility that the physical quantity (current, voltage, power, load, displacement) of either group will reach the end condition value first. In this case, similarly to the resistance control method, after the physical quantity of one set reaches the end condition value first, waits for the physical quantity of the other set to reach the end condition value, and the physical quantity of the other set reaches the end condition value. After a predetermined cooling time has elapsed since reaching the value, the next welding may be performed so that the respective groups start welding in synchronization.

  When m times of welding are completed (YES in step S7 in FIG. 4), 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 pressurizing mechanisms 21-1a, 21-1b, 21-2a, and 21-2b to be joined by the electrodes 20-1a, 20-1b, 20-2a, and 20-2b. After releasing the pressure to 24 (step S8 in FIG. 4), the insertion / extraction mechanism 41 is controlled. The insertion / extraction 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).

  Since the adsorption mechanisms 22-1a, 22-1b, 22-2a, 22-2b are vacuum-adsorbing BP28-1a, 28-1b, 28-2a, 28-2b until all the processing of the welding apparatus is completed. This vacuum adsorption acts as a force that resists the extraction of the intermediate electrodes 20-1c and 20-2c. Therefore, when the force required for the insertion / extraction mechanism 41 to pull out the intermediate electrodes 20-1c and 20-2c from the wound body 25 is small, BP28-1a, 28-1b, 28-2a, and 28-2b are wound bodies. 25 and the intermediate electrodes 20-1c and 20-2c together with the intermediate electrodes 20-1c and 20-2c may be detached from the wound body 25.

  The insertion / extraction mechanism 41 is provided with a load cell (not shown). The load cell converts the magnitude of the force required to pull out the intermediate electrodes 20-1c, 20-2c from the wound body 25 into an electric signal. The output of the load cell can be notified to the control unit 5. When the force required for the insertion / extraction mechanism 41 to pull out the intermediate electrodes 20-1c, 20-2c from the wound body 25 is equal to or less than a predetermined threshold (step S10 in FIG. 4), the control unit 5 is inappropriate for welding. For example, an alarm is issued by displaying an alarm message on the display unit 8 (step S11 in FIG. 4).

  Further, the vacuum pressure detector 4-1 detects the vacuum pressure of the suction mechanisms 22-1a and 22-1b, and the vacuum pressure detector 4-2 detects the vacuum pressure of the suction mechanisms 22-2a and 22-2b. If the insertion / extraction mechanism 41 can correctly extract the intermediate electrodes 20-1c, 20-2c from the wound body 25, the vacuum pressure detected by the vacuum pressure detectors 4-1, 4-2 increases (that is, the degree of vacuum decreases). To do). On the other hand, if the BP 28-1a, 28-1b, 28-2a, 28-2b is detached from the wound body 25 together with the intermediate electrodes 20-1c, 20-2c, the vacuum pressure remains low.

Therefore, when the insertion / extraction mechanism 41 pulls out the intermediate electrodes 20-1c, 20-2c from the wound body 25, the control unit 5 includes at least the vacuum pressure detected by the vacuum pressure detection units 4-1, 4-2. If one vacuum pressure is equal to or lower than a predetermined vacuum pressure threshold (step S12 in FIG. 4), it is determined that welding is inappropriate, and an alarm is issued by displaying an alarm message on the display unit 8, for example (step S11). ).
This completes the processing of the welding apparatus. The control unit 5 may cause the display unit 8 to display a waveform of a physical quantity detected during welding.

  As described above, in this embodiment, two sets of the upper electrode, the lower electrode, and the intermediate electrode are provided, and energization is performed so that the sets start welding in synchronization with each other. Since a total of four points are welded at a time, it is possible to eliminate the shunting of current that has become a problem when performing welding at a plurality of points in conventional resistance welding.

  As a result, in this embodiment, appropriate welding can be realized, and setting of welding conditions can be simplified. Moreover, in this Embodiment, since welding of several points is performed simultaneously, the frequency | count of welding can be reduced and the tact time of a welding process can be aimed at. Moreover, in this Embodiment, since the increase in the welding current accompanying a shunt can be eliminated, the capacity | capacitance per welding power supply can be made small.

  However, in order to eliminate the shunt, 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 are used. It is necessary to make the energization direction with respect to the to-be-joined object 24 the same. In the present embodiment, current flows from the upper electrode 20-1a to the lower electrode 20-1b, and simultaneously, current flows from the upper electrode 20-2a to the lower electrode 20-2b. The direction is the same.

  Further, in this embodiment, after performing resistance control type welding n times, welding of another control type is performed m times. In the first welding, the electrodes 20-1a to 20-1c and 20-2a to 20-2c are contaminated and an oxide film on the surface of the object to be joined is formed between the electrodes 20-1a and 20-1b and the electrodes 20-2a and 20b. -B is unstable. Therefore, in order to suppress the generation of dust, resistance control type welding is performed n times to remove dirt on 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 joined. When the resistance values R1 and R2 between the electrodes decrease and the energization path is stabilized, welding of another control method is performed m times. Thereby, in this Embodiment, the influence of the stain | pollution | contamination of the electrodes 20-1a-20-1c, 20-2a-20-2c and the oxide film of the to-be-joined surface can be reduced, and appropriate welding is implement | achieved. be able to.

  Moreover, you may employ | adopt the conventional control system as a control system of welding performed by step S6 of FIG. As a control method here, a constant current control method for supplying a predetermined welding current I for a certain time, a constant voltage control method for supplying a predetermined welding voltage V for a certain time, and a constant power for supplying a predetermined welding power W for a certain time. There are control methods.

  In this 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 an upper electrode, a lower electrode, and an intermediate electrode are provided, a total of six points can be welded simultaneously at the upper and lower three points of the workpiece 24. In this case, it is necessary to provide a welding power source, a physical quantity detection unit, and a vacuum pressure detection unit for each group.

  In the present embodiment, the current collector 26 is disposed above and below the wound body 25, but the current collector 26 is disposed only on either the upper side or the lower side of the wound body 25. May be. Since the BP is disposed so as to face the current collector 26 with a plurality of metal foils of the wound body 25 interposed therebetween, the current collector 26 is provided on the upper side or the lower side of the wound body 25. The BP is arranged only on the side. In addition, 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 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 peripheral surface of the wound body 25 are in direct contact with each other.

  Compared with the case where the current collector 26 is disposed above and below the wound body 25, when the current collector 26 is disposed only on either the upper side or the lower side of the wound body 25, the number of points that can be welded at one time is reduced. Although it is reduced, two sets of upper electrode, lower electrode and intermediate electrode can be welded simultaneously, and two points can be welded simultaneously, and three sets of upper electrode, lower electrode and intermediate electrode can be welded simultaneously. It is.

  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 into the wound body 25 in step S9. Although it is extracted from the inside 29, the present invention is not limited to this, and the insertion / extraction mechanism 41 may insert / extract the article 24 to / from the electrode.

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

  Further, the insertion / extraction mechanism 41 is configured such that the wound body 25, the current collector 26, and the BP 28-1a, 28-1b, 28-2a, 28-2b are welded to the workpiece 24 in the axial direction of the wound body 25. The electrodes 20-1a to 20-1c and 20-2a to 20-2c may be pulled out along (step S9).

In the present embodiment, vacuum suction pads of suction mechanisms 22-1a, 22-1b, 22-2a, and 22-2b are provided around the intermediate electrodes 20-1c and 20-2c. 20-2c itself may be provided with a suction nozzle.
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 of the present embodiment are as follows: a CPU (Central Processing Unit), a storage device, a computer having an interface with the outside, and these hardware resources It can be realized by a program to be controlled. The CPU executes the processing described in the present embodiment in accordance with a program stored in the storage device.

  The present invention can be applied to a technique for 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 ... pressurizing mechanism, 22-1a, 22-1b, 22-2a, 22-2b ... adsorption mechanism, 24 ... object to be joined, 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 laminated 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. A current collector on which a convex projection is formed, and a metal disposed inside the wound body so as to face the current collector with a plurality of metal foils of the wound body interposed therebetween A plurality of sets of first members arranged along the stacking direction of the metal foils so as to face each other with the objects to be joined interposed therebetween. A second electrode;
Provided for each set of the first and second electrodes inside the wound body, so that at least one of the two faces facing the inner peripheral surface of the wound body sandwiches the back plate. A plurality of third electrodes arranged to be aligned with the first and second electrodes;
A pressurizing mechanism that pressurizes at least one of the first and second electrodes and clamps the object to be joined by the first and second electrodes;
A plurality of welding power sources that are provided for each set of the first and second electrodes and supply current between the corresponding first and second electrodes;
Physical quantity detection means for detecting one or more physical quantities related to the workpieces being welded;
A current is supplied from the plurality of welding power sources to the plurality of first and second electrodes so that each group starts welding in synchronization, and one physical quantity detected during welding is a predetermined end condition. Control means for stopping energization of the first and second electrodes when the value is reached,
The welding apparatus, wherein the plurality of welding power supplies supply current to the plurality of sets of first and second electrodes so that energization directions to the objects to be joined are the same. The welding device according to claim 1,
When the resistance between the first and second electrodes, which is a physical quantity detected during welding, reaches a resistance value between electrodes set in advance as an end condition value, the control means is the first, After performing welding of the first control method for stopping energization of the second electrode n times (n is an integer of 1 or more), welding of the second control method different from the first control method is performed m The welding apparatus is characterized in that it is performed once (m is an integer of 1 or more). The welding apparatus according to claim 2, wherein
The welding of the second control method is welding that stops energization to the first and second electrodes when a physical quantity other than the interelectrode resistance detected during welding reaches a predetermined end condition value. ,
Physical quantities other than the interelectrode 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. The welding apparatus is any one of welding power, a load applied to the workpiece, and a displacement amount in the thickness direction of the workpiece. The welding apparatus according to claim 2, wherein
The second control type welding is a constant current control type welding in which a predetermined welding current is supplied to the first and second electrodes for a predetermined time, and a predetermined welding voltage is applied between the first and second electrodes. A welding apparatus comprising: constant voltage control type welding for supplying a predetermined time, or constant power control type welding for supplying a predetermined welding power to the first and second electrodes for a predetermined time. The welding apparatus according to any one of claims 1 to 4,
In the case where welding is performed a plurality of times, the control means waits for the slowest welding of the plurality of sets of first and second electrodes to finish, and then each group starts welding in synchronization. Thus, the welding apparatus is characterized in that the next welding is performed by supplying current from the plurality of welding power sources to the plurality of sets of first and second electrodes. The welding apparatus according to any one of claims 1 to 5,
The welding apparatus further includes a suction mechanism that vacuum-sucks the back plate and fixes the back plate to the surface of the third electrode facing the inner peripheral surface of the wound body. The welding apparatus according to claim 6, wherein
Furthermore, after welding is completed, the third electrode is pulled out from the article to be joined along the axial direction of the wound body, or the first, second, and third electrodes are pulled along the axial direction of the wound body. An insertion / extraction mechanism for extracting the object to be bonded from the electrode of
The force required for the insertion / extraction mechanism to pull out the third electrode from the workpiece or the force required to pull out the workpiece from the first, second, and third electrodes is less than a predetermined threshold. In this case, a welding apparatus comprising an alarm notification means for issuing an alarm. The welding apparatus according to claim 6, wherein
Furthermore, after welding is completed, the third electrode is pulled out from the article to be joined along the axial direction of the wound body, or the first, second, and third electrodes are pulled along the axial direction of the wound body. An insertion / extraction mechanism for extracting the object to be bonded from the electrode of
A vacuum pressure detecting means for detecting a vacuum pressure of the adsorption mechanism;
When the insertion / extraction mechanism pulls out the third electrode from the workpiece, or when the workpiece is pulled out from the first, second, or third electrode, the vacuum pressure detecting means detects A welding apparatus comprising alarm notification means for issuing an alarm when the vacuum pressure is a predetermined threshold value or less.

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