JP6186208B2 - Welding equipment - Google Patents

Description

  The present invention relates to a welding apparatus, and more particularly to a welding apparatus suitable for joining a laminate of a plurality of plates.

  In recent years, a stacked lithium ion battery in which a plurality of plate-like positive electrode and negative electrode are stacked via a separator has been used. FIG. 7A is a perspective view illustrating a state after stacking of the stacked lithium ion battery, and FIG. 7B is a perspective view illustrating a state where the tabs of the electrodes and the lead terminals are connected.

  In the stacked lithium ion battery, as shown in FIG. 7A, a positive electrode 100 made of a metal foil such as aluminum (Al) and a negative electrode 101 made of a metal foil such as copper (Cu) are separated (not shown). ) Are alternately stacked. Each positive electrode 100 is provided with tabs 102 for lead bonding. These tabs 102 are stacked as shown in FIG. 7B, and are bonded to lead terminals 104 for external connection at the joints 106. Is done. Similarly, each negative electrode 101 is provided with a tab 103 for lead bonding. These tabs 103 are stacked and bonded to a lead terminal 105 for external connection at a bonding portion 107.

Usually, ultrasonic welding, laser welding, and resistance welding are used for joining the tab 102 and the lead terminal 104 and joining the tab 103 and the lead terminal 105 (see Patent Document 1 and Patent Document 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.

  As shown in FIG. 8, resistance welding is performed by sandwiching and pressing a plurality of tabs 102 (or tabs 103) and lead terminals 104 (or lead terminals 105) between a pair of electrodes 108a and 108b from above and below. This is a method in which a current is passed through 108b and the tab 102 (or tab 103) and the lead terminal 104 (or lead terminal 105) are melted and joined by the generated Joule heat.

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 tabs increases due to an increase in the number of electrodes, the required welding energy increases, so it is necessary to increase the output of ultrasonic waves, and the tabs may be torn or cut.
In laser welding, there is a problem that a high-energy laser beam is required because of the high reflectance of an object made of Al or 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 damage to a tab which become a problem by ultrasonic welding and laser welding can be suppressed. However, since the electrical resistance of the object made of Al or Cu is low and hardly generates heat, it is necessary to pass a large current through the electrodes in order to join a plurality of tabs, and the consumption of the electrodes that become high temperature is severe. There was a problem. In particular, when trying to join a tab made of Al foil using a commonly used Cu alloy electrode, Cu as the main component of the electrode and Al as the main component of the tab undergo an alloying reaction. -The electrode tip is remarkably consumed by the production of Al alloy, so the electrode must be polished frequently.
In order to improve such electrode wear, a method of interposing a strip-shaped conductive material made of Cu between the electrode and the object to be joined has been adopted (see Patent Document 3).

JP 2008-66170 A JP 2009-32670 A Japanese Patent No. 2867777

  The technique described in Patent Document 3 requires a strip-shaped conductive material made of Cu and a transport mechanism for transporting the strip-shaped conductive material, so that there is a problem that the periphery of the electrode is complicated and the cost is high. There was a point. Further, since the strip-shaped conductive material and its transport mechanism are arranged around the electrode, there are problems that the arrangement space of the electrode itself is limited and the maintenance of the electrode becomes difficult.

  In resistance welding, the energization current and the voltage between the electrodes are fed back to the welding power source, and the energization amount to the electrodes is controlled so that the set current, power and voltage are applied to the workpiece for a certain period of time. Such an energization control method for a certain period of time has a problem in that when a laminated body of a plurality of plates is welded, the welding state is not stable and a high-quality nugget (joint portion) cannot be obtained.

When welding a laminate of a plurality of plates made of Al, Cu, etc., the oxide film on the surface of the plate acts as an insulator, so it is necessary to destroy the oxide film by applying a high voltage between the electrodes during welding. . However, since there is a variation in the oxide film destruction phenomenon, the conventional control method in which the energization time to the electrode is constant cannot cope with this variation, and appropriate welding cannot be realized.
The above-mentioned problems are not limited to the stacked lithium ion battery, and similarly occur when a plurality of Al foils and Cu foils are joined.

  The present invention has been made to solve the above-described problems, and can suppress the consumption of the electrodes with a simple configuration, and can realize appropriate welding even when a laminated body of a plurality of plates is welded. An object of the present invention is to provide a welding apparatus capable of performing the above.

The welding apparatus of the present invention includes a first electrode that comes into contact with a workpiece, a second electrode that faces the first electrode with the workpiece interposed therebetween, and the first and second electrodes A pressurizing mechanism that pressurizes at least one of the first and second electrodes, a welding power source that supplies current between the first and second electrodes, Detection means for detecting one or more physical quantities related to the object to be joined, and welding is started by supplying current from the welding power source to the first and second electrodes according to an instruction from the outside. Control means for stopping energization of the first and second electrodes when one of the physical quantities detected in the step reaches a predetermined end condition value, and the object to be joined is a plurality of sheets made of metal. And a plate-like member made of metal disposed on the laminate. Is composed of a current collector convex projection is formed to the body, and the made of metal is arranged below the stack plate-shaped back plate, the height of the projection, the object to be bonded Is set to a height at which the current collector and the laminate are not in contact with each other in the portion other than the projection when the projection is deformed, and the thickness of the back plate is set at the time of welding. The thickness is set such that the portion in contact with the body melts and the portion in contact with the lower second electrode does not melt, and the physical quantity is the welding current flowing through the first and second electrodes, the first and second Welding voltage applied between the electrodes, welding power supplied to the first and second electrodes, resistance between the first and second electrodes, load applied to the workpiece, and the joint The amount of displacement in the thickness direction of the object It is an feature.

Further, the welding apparatus of the present invention includes a first electrode that contacts the object to be bonded, a second electrode that faces the first electrode with the object to be bonded in between, and the first and second electrodes. A pressurizing mechanism that pressurizes at least one of the electrodes and clamps the object to be joined between the first and second electrodes, a welding power source that supplies current between the first and second electrodes, and welding. Detecting means for detecting one or more physical quantities relating to the object to be joined, and starting welding by supplying current from the welding power source to the first and second electrodes according to an instruction from the outside, Control means for stopping energization of the first and second electrodes when one physical quantity detected during welding reaches a predetermined end condition value, and the workpiece is made of metal. With a laminate of a plurality of plates and a plate-like member made of metal disposed on the laminate, And a plate-like back plate made of metal disposed under the laminate, and the lower surface of the back plate is vacuumed. An adsorption mechanism for adsorbing and fixing the object to be bonded on the second electrode on the lower side, wherein the physical quantity is a welding current flowing through the first and second electrodes, the first, A welding voltage applied between the second electrodes, a welding power supplied to the first and second electrodes, a resistance between the first and second electrodes, a load applied to the workpiece, It is a displacement amount in the thickness direction of the object to be joined .
Further, in one configuration example of the welding apparatus of the present invention, the control means is configured such that when the interelectrode resistance, which is a physical quantity detected during welding, reaches an interelectrode resistance value set in advance as an end condition value. After performing welding of the first control method for stopping energization to the first and second electrodes n times (n is an integer equal to or greater than 1), a second control method different from the first control method is used. Welding is performed 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 one physical quantity other than the interelectrode resistance detected during welding reaches a predetermined end condition value. 1. Welding that stops energization of the second electrode.
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 interelectrode resistance detected during welding of the first control method when the welding time per one time exceeds a predetermined elapsed time is an end condition. When the value does not reach the inter-electrode resistance value set in advance as a value, it is provided with an alarm notification means for stopping energization to the first and second electrodes and issuing an alarm.
Further, in one configuration example of the welding apparatus of the present invention, the control means uses a differential value or an integral value of the physical quantity as the value of the physical quantity to be compared with the end condition value.

  According to the present invention, the current collector on which the projection is formed with respect to the multilayer body is disposed on the multilayer body, and the back plate is disposed below the multilayer body, so that the melting part is first, Since the second electrode can be prevented from reaching, the transfer of the metal from the object to be joined to the first and second electrodes can be reduced, and the consumption of the first and second electrodes can be suppressed. Can do. In the present invention, since the configuration around the electrodes is simplified, the arrangement space of the first and second electrodes is not limited. In addition, replacement of the first and second electrodes is facilitated, and maintenance is facilitated. Further, in the present invention, when welding the workpieces, the physical quantity detected during welding is monitored in real time, and when the physical quantity reaches a predetermined end condition value, the first and second electrodes are monitored. Compared with the conventional control method in which the energization time is constant, the influence of the variation of the oxide film on the surface of the object to be bonded can be reduced, and a laminate of a plurality of plates is welded. Even in this case, appropriate welding can be realized. 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.

  Further, in the present invention, by providing an adsorption mechanism, an object to be bonded having a stacked structure including a current collector, a stacked body, and a back plate can be easily fixed on the second electrode.

  In the present invention, the first and second electrodes are deenergized when the inter-electrode resistance detected during welding reaches a predetermined inter-electrode resistance value as an end condition value. By performing the control-type welding n times, it is possible to reduce the influence of the dirt on the electrodes and the oxide film on the surface of the object to be joined, thereby realizing appropriate welding.

  Further, in the present invention, the interelectrode resistance detected during welding of the first control method when the welding time per one time exceeds a predetermined elapsed time is set in advance as an end condition value. By issuing an alarm when the value does not reach the value, the user can be informed of the malfunction of the object to be joined.

  In the present invention, the influence of noise superimposed on the physical quantity can be avoided by using the differential value or the integral value of the physical quantity as the physical quantity value to be compared with the end condition value.

It is a block diagram which shows the structure of the welding apparatus which concerns on the 1st Embodiment of this invention. It is an expanded sectional view of the welding head concerning a 1st embodiment of the present 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 a flowchart which shows operation | movement of the welding apparatus which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the state after lamination | stacking of a lamination type lithium ion battery, and the state which connected the tab and lead terminal of the electrode. It is an expanded sectional view of the joined part in resistance welding.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the welding apparatus according to the first embodiment of the present invention. The welding apparatus of the present embodiment includes a start switch 2, a rectifier circuit 3, a capacitor 4, an inverter 5, a welding transformer 6, a diode 7, a welding head 8, a hall element 9, and a current detection unit 10. The voltage detection unit 11, the power detection unit 12, the resistance detection unit 13, the load detection unit 14, the displacement detection unit 15, the control unit 16, the operation unit 17, the storage unit 18, and the display unit 19. And have.

  The start switch 2, the rectifier circuit 3, the capacitor 4, the inverter 5, the welding transformer 6, and the diode 7 constitute a welding power source that supplies current to the welding head 8. In addition, the Hall element 9, the current detection unit 10, the voltage detection unit 11, the power detection unit 12, the resistance detection unit 13, the load detection unit 14, and the displacement detection unit 15 detect a physical quantity related to the workpiece to be welded. It constitutes a detection means. Moreover, the control part 16 and the display part 19 comprise the alarm notification means.

  FIG. 2 is an enlarged sectional view of the welding head 8. The welding head 8 includes electrodes 80a and 80b. The electrodes 80a and 80b are composed of electrode bodies 81a and 81b made of a Cu alloy, and tip portions 82a and 82b made of a Cu alloy. The tip portions 82a and 82b can be easily replaced. Further, the welding head 8 includes thermocouples 83a and 83b attached to the tip portions 82a and 82b, pressurizing mechanisms 84a and 84b for raising and lowering the electrodes 80a and 80b to sandwich and pressurize the object 86, and a back to be described later. And a suction mechanism 85 for vacuum-sucking the plate. Reference numeral 88 in FIG. 2 denotes a suction nozzle of the suction mechanism 85.

  The pressurizing mechanisms 84a and 84b are provided with load cells (not shown) so that the magnitude of the load applied to the workpiece 86 can be converted into an electrical signal. The pressurizing mechanisms 84a and 84b are provided with a displacement sensor (not shown) so that the displacement amount in the thickness direction of the object 86 can be converted into an electric signal. In addition, although the temperature of the front-end | tip part 82a, 82b can be detected based on the voltage from the thermocouple 83a, 83b, in this Embodiment, the thermocouple 83a, 83b is not an essential component requirement.

  Next, the workpiece 86 of this embodiment will be described. The object to be bonded 86 is a laminate 86a of a plurality of plates made of Al or Al alloy, and a plate-like member made of Al or Al alloy disposed on the laminate 86a, and is convex with respect to the laminate 86a. A current collector 86b on which a projection 87 as a projection is formed, and a back plate (hereinafter referred to as BP) 86c, which is a plate-like member made of Al or an Al alloy, disposed below the laminated body 86a. The thickness per sheet of the plurality of sheets (Al foil) constituting the laminated body 86a is, for example, about 10 μm to 150 μm.

  The height h of the projection 87 is such that when the object 87 is sandwiched between the electrodes 80a and 80b from the upper and lower sides and a predetermined load is applied and the projection 87 is deformed and lowered, the current collector 86b is at a portion other than the projection. Is set to a height at which the stacked body 86a is not in contact (when the current collector 86b is 1 mm thick, the height of the projection 87 is about 1 mm). The horizontal dimension of the projection 87 is such that the contact area between the projection 87 and the laminated body 86a when the projection 87 is deformed and lower is smaller than the contact area between the tip 82a of the electrode 80a and the current collector 86b. Is set to The thickness of the BP 86c may be set to a thickness at which the portion in contact with the stacked body 86a melts during welding and the portion in contact with the tip portion 82b of the electrode 80b does not melt, which is 1 of the thickness of the current collector 86b. / 2 or more is appropriate.

  Hereinafter, the operation of the welding apparatus will be described. First, as shown in FIG. 2, the pressurizing mechanisms 84a and 84b of the welding head 8 sandwich and press the workpiece 86 from above and below (the direction along the stacking direction of the stacked body 86a) with the electrodes 80a and 80b. At this time, in order to place the article to be bonded 86 on the electrode 80b, the lower surface of the BP 86c is vacuum-sucked by the suction mechanism 85 and fixed so that the BP 86c is placed on the tip portion 82b of the electrode 80b. As described above, the stacked body 86a is placed on the BP 86c, and the current collector 86b is placed on the stacked body 86a. Then, the electrode 80a is lowered and pressed on the current collector 86b. In the example of FIG. 2, the pressurizing mechanisms 84a and 84b apply pressure to the electrodes 80a and 80b, respectively, but pressure may be applied to only one of the electrodes 80a and 80b. Needless to say.

  For example, when the user operates the operation unit 17 to instruct the start of welding, a start signal is output from the operation unit 17 and the start switch 2 is turned on. When the start switch 2 is turned on, the rectifier circuit 3 performs full-wave rectification on the AC output of the commercial three-phase AC power supply 1 of AC 200V, and charges the capacitor 4 connected in parallel between the output terminals of the rectifier circuit 3. This rectifier circuit 3 is constituted by a three-phase full-wave mixing bridge using six diodes 30.

  The inverter 5 converts the charging voltage of the capacitor 4 into an AC voltage and supplies it to the primary side of the welding transformer 6. The inverter 5 is constituted by a bridge composed of four NPN transistors 50. The secondary output of the welding transformer 6 is full-wave rectified by a rectifier (diode) 7 and guided to the electrodes 80a and 80b. Thus, a large current is passed between the electrodes 80a and 80b, and the joining surface (joint surface between the metals) of the article 86 is melted and joined by the generated Joule heat. In the present embodiment, the projection 87 of the current collector 86b is deformed and lowered by the pressurization by the pressurization mechanisms 84a and 84b, and the front end portion of the projection 87 and the stacked body 86a at a position directly below the projection 87; The BP 86c immediately below the projection 87 is melted, and the current collector 86b, the stacked body 86a, and the BP 86c are joined.

  The current detection unit 10 detects the current I flowing through the secondary side of the welding transformer 6 (that is, the welding current flowing through the electrodes 80a and 80b) from the output of the Hall element 9 provided on the secondary side of the welding transformer 6. . The voltage detector 11 detects the welding voltage V applied between the electrodes 80a and 80b. The power detection unit 12 integrates the value of the welding current I detected by the current detection unit 10 and the value of the welding voltage V detected by the voltage detection unit 11, thereby obtaining the welding power W supplied to the electrodes 80a and 80b. To detect. The resistance detector 13 calculates the resistance R between the electrodes 80a and 80b from the value of the welding voltage V detected by the voltage detector 11 and the value of the welding current I detected by the current detector 10. The load detection unit 14 detects the load G applied to the workpiece 86 based on the output of the load cell provided in the pressurization mechanisms 84a and 84b. The displacement detection unit 15 detects the displacement amount D in the thickness direction of the workpiece 86 based on the output of the displacement sensor provided in the pressurizing mechanisms 84a and 84b.

  3 is a diagram showing an example of changes in welding current I, welding voltage V, and welding power W during welding, FIG. 4 is a diagram showing an example of changes in interelectrode resistance R during welding, and FIG. 5 is during welding. It is a figure which shows an example of the change of the load G of this, and the displacement amount D. FIG. The horizontal axis in FIGS. 3 to 5 is time. In the example of FIG. 3, the welding current I and the welding voltage V are described only for positive pulses. However, since an AC voltage is applied to the primary side of the welding transformer 6, the welding current I and the welding voltage are described. In some cases, V is a negative pulse.

  The control unit 16 operates the inverter 5 to generate an alternating voltage, thereby applying a pulse current as shown in FIG. 3 to the electrodes 80a and 80b, and monitoring a physical quantity detected during welding in real time. When the physical quantity reaches a predetermined end condition value, the operation of the inverter 5 is stopped, the energization to the electrodes 80a and 80b is terminated, and after a predetermined cooling time (for example, several msec) has elapsed from the end of the energization. Then, the next pulse current is applied.

In the storage unit 18, 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 in advance using the object to be joined 86 and set a physical quantity value in the storage unit 18 when appropriate welding is obtained. That's fine.

When the current control based on the feedback of the welding current I is performed, the control unit 16 monitors the welding current I detected by the current detection unit 10 for each energization pulse as shown in FIG. Is reached when the welding current value I ₀ preset in the storage unit 18 reaches the welding current value I ₀ . When performing voltage control based on feedback of the welding voltage V, the control unit 16 monitors the welding voltage V detected by the voltage detection unit 11 for each energization pulse, and the absolute value of the welding voltage V is stored in the storage unit 18. When the welding voltage value V ₀ set in advance is reached, the energization is terminated. When performing power control based on feedback of the welding power W, the control unit 16 monitors the welding power W detected by the power detection unit 12 for each energization pulse, and the welding power W is preset in the storage unit 18. Energization is terminated when the welding power value W ₀ is reached.

Further, when performing resistance control based on feedback of the interelectrode resistance R, the control unit 16 monitors the interelectrode resistance R detected by the resistance detection unit 13 for each energization pulse, and the interelectrode resistance R is stored in the storage unit 18. When the predetermined interelectrode resistance R ₀ is reached, the energization is terminated. When the load control based on the feedback of the load G is performed, the control unit 16 monitors the load G detected by the load detection unit 14 for each energization pulse, and the load G is a load value G set in the storage unit 18 in advance. _When it reaches ₀ , the power is turned off. When performing the displacement control based on the feedback of the displacement amount D, the control unit 16 monitors the displacement amount D detected by the displacement detection unit 15 for each energization pulse, and the displacement amount D is preset in the storage unit 18. Energization is terminated when the displacement amount D ₀ is reached.

The control unit 16 determines which control method of physical quantity control (current control, voltage control, power control, resistance control, load control, displacement control) to be adopted by the user who has operated the operation unit 17. Decide according to your choice.
Further, the control unit 16 causes the display unit 19 to display the waveform of the physical quantity detected during welding.

  As described above, in this embodiment, the stacked body 86a, the current collector 86b disposed on the stacked body 86a, and the BP 86c disposed below the stacked body 86a are used as the objects to be bonded 86. Al transfer from the bonded object 86 to the tips 82a and 82b of the electrodes 80a and 80b can be reduced, and consumption of the tips 82a and 82b can be suppressed. By providing a projection 87 on the current collector 86b and making the height of the projection 87 higher than the projection used in normal projection welding, it is possible to eliminate the shunting of the welding current at portions other than the projection, and the thickness of the BP 86c. Since the distance between the melted portion and the tip portions 82a and 82b can be increased by setting the thickness to ½ or more of the thickness of the current collector 86b, a temperature gradient along the stacking direction of the stacked body 86a can be obtained, and the melted portion Can be prevented from reaching the tip portions 82a, 82b.

  That is, on the current collector 86b side, the welding current (heat) is concentrated at the tip of the projection 87 in contact with the stacked body 86a. Since the contact area between the tip portion 82a of the electrode 80a and the current collector 86b is larger than the contact area between the tip portion of the projection 87 and the stacked body 86a, the contact portion between the tip portion 82a of the electrode 80a and the current collector 86b There is no concentration of welding current. Therefore, the current collector 86b melts at the tip of the projection 87 in contact with the stacked body 86a, and the portion of the current collector 86b in contact with the tip 82a of the electrode 80a is difficult to melt. As described above, since the melted portion of the current collector 86b can be prevented from reaching the tip end portion 82a of the electrode 80a, transfer of Al from the current collector 86b to the tip end portion 82a can be reduced.

  On the other hand, by pressing the laminated body 86a with the projection 87, the oxide film resistance value of a plurality of plates (Al foil) constituting the laminated body 86a can be lowered. When the welding current is concentrated, a large amount of current flows toward the BP 86 c at a position directly below the projection 87. Therefore, the laminated body 86a made of a plurality of plates (Al foil) is melted at a portion located directly below the projection 87, and the melted part of the BP 86c that is in contact with the laminated body 86a is also a part of the projection 87. This is the part directly below. Since the thickness of the BP 86c is ½ or more of the thickness of the current collector 86b, and the contact area between the tip portion 82b of the electrode 80b and the BP 86c is larger than the contact area between the tip portion of the projection 87 and the stacked body 86a. The portion of BP86c that is in contact with the tip portion 82b of the electrode 80b is difficult to melt. As described above, since the melted portion of the BP 86c can be prevented from reaching the tip portion 82b of the electrode 80b, the transfer of Al from the BP 86c to the tip portion 82b can be reduced.

  In the present embodiment, it is only necessary to add the suction mechanism 85 around the electrodes, and there is no need to provide a belt-like conductive material and its transport mechanism unlike the technique described in Patent Document 3. Therefore, the configuration around the electrodes can be simplified. In the present embodiment, since the configuration around the electrodes is simplified, the arrangement space of the electrodes 80a and 80b is not limited. In addition, the attachment and replacement of the tip portions 82a and 82b to the electrode bodies 81a and 81b are facilitated, and maintenance of the electrodes 80a and 80b is facilitated. In the present embodiment, the suction nozzle 88 of the suction mechanism 85 is provided around the electrode, but the suction nozzle may be provided on the electrode 80b (electrode body 81b, tip portion 82b).

  Further, in the conventional resistance welding, the tip of the electrode is tapered in order to concentrate the welding current, but in this embodiment, since the concentration of the welding current can be realized by the projection 87, the tip 82a and 82b should just be cylindrical form of fixed thickness, and can produce and maintain the front-end | tip parts 82a and 82b easily.

  In the present embodiment, when resistance welding of the workpiece 86 is performed, the physical quantity detected during welding is monitored in real time, and the electrodes 80a and 80b are reached when the physical quantity reaches a predetermined end condition value. Since the energization of the electrode is terminated, compared to the conventional control method in which the energization time is made constant, the influence of the variation of the oxide film on the surface of the workpiece can be reduced, and appropriate welding can be realized. . Moreover, in this Embodiment, generation | occurrence | production of metal powder and damage to the to-be-joined object 86 can be avoided similarly to the conventional resistance welding.

In this embodiment, instantaneous values of physical quantities (welding current I, welding voltage V, welding power W, interelectrode resistance R, load G, displacement amount D) detected during welding are set to predetermined end condition values ( Welding current value I ₀ , welding voltage value V ₀ , welding power value W ₀ , interelectrode resistance value R ₀ , load value G ₀ , displacement amount D ₀ ), but is not limited to this, physical quantity May be compared with the end condition value, and the energization of the electrodes 80a and 80b may be terminated when the physical quantity derivative value or integral value reaches the end condition value. Since noise is superimposed on the physical quantity detected during welding, the influence of noise can be avoided by using the differential value or integral value of the physical quantity.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, a more specific example of control will be described. Also in the present embodiment, the configurations of the welding apparatus and the objects to be joined are the same as those in the first embodiment, and therefore, description will be made using the reference numerals in FIGS. FIG. 6 is a flowchart showing the operation of the welding apparatus of the present embodiment. In the following description, one pulse current as shown in FIG. 3 is applied to the electrodes 80a and 80b as one time.

First, when the control unit 16 is instructed to start welding by the user, the control unit 16 performs welding by a resistance control method using an interelectrode resistance value R ₀ preset in the storage unit 18 as an end condition value (step S1 in FIG. 6). . The resistance control type welding method is as described in the first embodiment. At this time, the control unit 16 performs resistance control type welding n times (n is an integer of 1 or more). 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 ₁ that is the second end condition value are such that R ₀ > R ₁ . 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).

Next, the control unit 16 finishes the resistance control method n times (YES in step S2 in FIG. 6), 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 S3 in FIG. 6). As a control method other than the resistance control method, as described in the first embodiment, a current control method using the welding current value I ₀ as an end condition value, and a voltage control method using the welding voltage value V ₀ as an end condition value. There are a power control method using the welding power value W ₀ as an end condition value, a load control method using the load value G ₀ as an end condition value, and a displacement control method using the displacement amount D ₀ as an end condition value. The control unit 16 performs welding of these control methods 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, the next welding is performed after a predetermined cooling time has elapsed from the end of one welding (at the end of energization). When the m times of welding are completed (YES in step S4 in FIG. 6), the processing of the welding apparatus is completed.

  As described above, in the present embodiment, after performing resistance control type welding n times, welding of another control type is performed m times. In the first welding, the current path between the electrodes 80a and 80b is unstable due to contamination of the electrodes 80a and 80b and an oxide film on the surface of the workpiece. Therefore, in order to suppress the generation of dust, resistance control type welding is performed n times to remove the dirt on the electrodes 80a and 80b and the oxide film on the surface of the object to be bonded, and the resistance value R between the electrodes decreases, and the current path When is stabilized, welding of another control method is performed m times. Thereby, in this Embodiment, the influence of the dirt of electrodes 80a and 80b and the oxide film of the to-be-joined surface can be reduced, and appropriate welding can be implement | achieved.

  In the present embodiment, the resistance value in the stacking direction of the stacked body 86a before welding is, for example, several tens mΩ to several hundred mΩ, but this resistance is obtained by pressing with the projection 87 as described in the first embodiment. The value can be reduced to several mΩ to several tens of mΩ, and the resistance value is reduced to 0.1 by performing resistance control type welding n times as in the present embodiment. It can be reduced to about several mΩ.

  When the resistance control method welding is performed, if the inter-electrode resistance R detected by the resistance detection unit 13 does not reach the end condition value preset in the storage unit 18, there is a problem with the article 86 to be joined. Is expected. Therefore, when the inter-electrode resistance R does not reach the end condition value when the welding time per time exceeds a predetermined elapsed time, the control unit 16 stops energizing the electrodes 80a and 80b, for example, the display unit An alarm message may be displayed by displaying an alarm message on 19.

  Moreover, you may employ | adopt the conventional control system as a control system of welding performed by step S3 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.

  The functions of the control unit 16, the operation unit 17, the storage unit 18, and the display unit 19 in the first and second embodiments are a CPU (Central Processing Unit), a computer having a storage device and an external interface, and these It can be realized by a program that controls the hardware resources. The CPU executes the processing described in the first and second embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to a resistance welding apparatus.

  DESCRIPTION OF SYMBOLS 1 ... Three-phase alternating current power supply, 2 ... Start switch, 3 ... Rectifier circuit, 4 ... Capacitor, 5 ... Inverter, 6 ... Welding transformer, 7 ... Diode, 8 ... Welding head, 9 ... Hall element, 10 ... Current detection part, DESCRIPTION OF SYMBOLS 11 ... Voltage detection part, 12 ... Electric power detection part, 13 ... Resistance detection part, 14 ... Load detection part, 15 ... Displacement detection part, 16 ... Control part, 17 ... Operation part, 18 ... Memory | storage part, 19 ... Display part, 80a, 80b ... electrode, 81a, 81b ... electrode body, 82a, 82b ... tip, 83a, 83b ... thermocouple, 84a, 84b ... pressurizing mechanism, 85 ... adsorption mechanism, 86 ... joined object, 86a ... laminate 86b ... current collector, 86c ... back plate, 87 ... projection, 88 ... suction nozzle.

Claims (7)

A first electrode in contact with an object to be joined;
A second electrode facing the first electrode with the object to be joined in-between;
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 welding power source for supplying a current between the first and second electrodes;
Detecting means for detecting one or more physical quantities related to the workpieces being welded;
In response to an instruction from the outside, current is supplied from the welding power source to the first and second electrodes to start welding, and one physical quantity detected during welding reaches a predetermined end condition value And a control means for stopping energization to the first and second electrodes,
The object to be joined is a laminated body of a plurality of plates made of metal and a plate-like member made of metal disposed on the laminated body, and a projection in which a convex projection is formed on the laminated body. It is composed of an electric body and a plate-like back plate made of metal disposed under the laminate,
The height of the projection is set to a height at which the current collector and the laminate are not in contact with each other at the portion other than the projection when the object to be bonded is pressurized and the projection is deformed.
The thickness of the back plate is set to a thickness at which the portion in contact with the laminate is melted during welding and the portion in contact with the lower second electrode is not melted,
The physical quantity includes welding current flowing through the first and second electrodes, welding voltage applied between the first and second electrodes, welding power supplied to the first and second electrodes, 1. A welding apparatus comprising: a resistance between first and second electrodes; a load applied to the workpiece; and a displacement in a thickness direction of the workpiece. A first electrode in contact with an object to be joined;
A second electrode facing the first electrode with the object to be joined in-between;
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 welding power source for supplying a current between the first and second electrodes;
Detecting means for detecting one or more physical quantities related to the workpieces being welded;
In response to an instruction from the outside, current is supplied from the welding power source to the first and second electrodes to start welding, and one physical quantity detected during welding reaches a predetermined end condition value And a control means for stopping energization to the first and second electrodes,
The object to be joined is a laminated body of a plurality of plates made of metal and a plate-like member made of metal disposed on the laminated body, and a projection in which a convex projection is formed on the laminated body. It is composed of an electric body and a plate-like back plate made of metal disposed under the laminate,
Furthermore, a suction mechanism is provided that vacuum-sucks the lower surface of the back plate so that the object to be joined is placed on the second electrode on the lower side,
The physical quantity includes welding current flowing through the first and second electrodes, welding voltage applied between the first and second electrodes, welding power supplied to the first and second electrodes, 1. A welding apparatus comprising: a resistance between first and second electrodes; a load applied to the workpiece; and a displacement in a thickness direction of the workpiece. The welding apparatus according to claim 1 or 2 ,
The control means stops the energization to the first and second electrodes when an interelectrode resistance, which is a physical quantity detected during welding, reaches an interelectrode resistance value set in advance as an end condition value. After performing welding of the first control method n times (n is an integer of 1 or more), further, welding of the second control method different from the first control method is performed m times (m is an integer of 1 or more). A welding apparatus characterized by that. The welding device according to claim 3 ,
The welding of the second control method is a welding in which energization to the first and second electrodes is stopped when one physical quantity other than the interelectrode resistance detected during welding reaches a predetermined end condition value. Welding apparatus characterized by being. The welding device according to claim 3 ,
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 3 to 5 ,
Furthermore, when the welding time per one time exceeds a predetermined elapsed time, the interelectrode resistance detected during the welding of the first control method reaches a predetermined interelectrode resistance value as an end condition value. A welding apparatus comprising alarm notification means for stopping energization to the first and second electrodes to issue an alarm when not. The welding apparatus according to any one of claims 1 to 6 ,
The control device uses a differential value or an integral value of a physical quantity as the value of the physical quantity to be compared with the end condition value.

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