Copper bar, manufacturing method of copper bar and electronic equipment

Abstract

The invention relates to the technical field of integrated circuits, and discloses a copper bar, a manufacturing method of the copper bar and electronic equipment, and the copper bar comprises a first copper bar unit, a second copper bar unit, a one-way conduction device unit and a switching device unit. The first end of the one-way conduction device unit is connected with the first copper bar unit, the second end of the one-way conduction device unit is connected with the first end of the switching device unit, and the second end of the switching device unit is connected with the second copper bar unit; the third end of the switching device unit is connected with an external controller; the switching device unit is determined to be in an on state or an off state through a control signal sent by the controller; and when the switching device unit is in an on state, the one-way conduction device unit controls the current of the first copper bar unit to flow to the second copper bar unit. The one-way conduction device unit is connected with the switching device unit and is located between the first copper bar unit and the second copper bar unit after connection, simple connection between devices is set, and the purpose of device miniaturization is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a copper busbar, a method for manufacturing the copper busbar, and an electronic device. Background Art

[0002] In the prior art, copper busbars are long strip conductors made of pure copper, which have excellent electrical conductivity and good mechanical strength. The main function of copper busbars is to be used as conductors for large current transmission. When current passes through the copper busbar, due to the low resistance of copper, the current can pass smoothly without generating excessive heat. This makes copper busbars very efficient and reliable in large current transmission.

[0003] Copper busbars are widely used in power systems, industrial automation, transportation, home appliances, data centers and other fields due to their excellent electrical conductivity and mechanical strength. For example, copper busbars can be directly crimped onto mechanical relays by bolts, so that the contacts of the relays are in the form of copper busbars, which is suitable for large currents. However, this method requires numerous wiring harnesses, huge structural layout space, and a complicated installation process, which is not conducive to the miniaturization and wirelessization of the components. Summary of the invention

[0004] The embodiments of the present application provide a copper busbar, a method for manufacturing the copper busbar, and an electronic device. By arranging components of the copper busbar, the components are simply connected, thereby achieving the purpose of miniaturization of the components.

[0005] In a first aspect, an embodiment of the present application provides a copper bar, the copper bar comprising: a first copper bar unit, a second copper bar unit, a unidirectional conductive device unit and a switch device unit; a first end of the unidirectional conductive device unit is connected to the first copper bar unit, a second end of the unidirectional conductive device unit is connected to the first end of the switch device unit, and a second end of the switch device unit is connected to the second copper bar unit; a third end of the switch device unit is connected to an external controller;

[0006] The switch device unit is used to determine whether it is in an on state or an off state through the control signal sent by the controller;

[0007] The one-way conductive device unit is used to control the current of the first copper bar unit to flow to the second copper bar unit when the switch device unit is in an on state.

[0008] Compared with the prior art, the present application sets a unidirectional conductive device unit to be connected with the switch device unit, and after the connection, it is located between the first copper bar unit and the second copper bar unit, and uses the device characteristics of the switch device unit itself to control the entire device to be in an on state or an off state. When the switch device unit is in the on state, the direction of the overall current is controlled by the device characteristics of the unidirectional conductive device unit itself. Furthermore, by setting a simple connection between the devices, the purpose of miniaturization of the device can be achieved.

[0009] In a possible embodiment, the unidirectional conductive device unit includes a plurality of diodes, and each of the diodes is connected in parallel, the anode of each of the diodes constitutes the first end of the unidirectional conductive device unit, and the cathode of each of the diodes constitutes the second end of the unidirectional conductive device unit.

[0010] The present application sets the specific device of the unidirectional conduction device unit as a diode and sets the specific connection method of the diode. Through the simple device of the diode, the unidirectional conduction function of the unidirectional conduction device unit is realized, and the purpose of miniaturization of the device can be achieved.

[0011] In a possible embodiment, the switching device unit includes a plurality of metal oxide semiconductor field effect MOS transistors, each of the MOS transistors is connected in parallel, the drain of each of the MOS transistors constitutes the first end of the switching device unit, the source of each of the MOS transistors constitutes the second end of the switching device unit, and the gate of each of the MOS transistors constitutes the third end of the switching device unit.

[0012] The present application sets the specific device of the switch device unit to be a MOS tube and sets a specific connection method of the MOS tube. Through the simple device of the MOS tube, the on and off functions of the switch device unit are realized, and the purpose of miniaturization can be achieved.

[0013] In a possible embodiment, the copper busbar further includes:

[0014] Input reference signal lead wire and drive signal reference lead wire;

[0015] The input reference signal lead wire is a lead wire led out from the first end of the switch device unit, and the drive signal reference lead wire is a lead wire led out from the second end of the switch device unit;

[0016] The input reference signal lead wire and the drive signal reference lead wire are used to detect the voltage between the first end and the second end of the switch device unit.

[0017] The present application sets an input reference signal lead wire and a drive signal reference lead wire in the copper busbar, and uses the input reference signal lead wire and the drive signal reference lead wire to detect the voltage between the first end and the second end of the switching device unit, and then can use the control signal to accurately determine whether the switching device unit is turned on or off.

[0018] In a possible embodiment, the switching device unit is specifically used to determine that it is in an off state through a control signal sent by the controller when a voltage value between a first end and a second end of the switching device unit is greater than a preset voltage value.

[0019] The present application detects the voltage between the first end and the second end of the switch device unit, and then can use the control signal to accurately determine whether the switch device unit is turned on or off.

[0020] In a possible embodiment, a gap between the first copper bar unit and the second copper bar unit except for the one-way conductive device unit and the switch device unit is filled with insulating material.

[0021] The present application can ensure electrical safety between the first copper bar unit and the second copper bar unit by filling the gap between the first copper bar unit and the second copper bar unit with insulating material.

[0022] In a possible embodiment, the total area of ​​the insulating material is larger than the area of ​​the spatial overlap region of the first copper bar unit and the second copper bar unit.

[0023] The present application can more accurately ensure the electrical safety between the first copper bar unit and the second copper bar unit by setting the total area of ​​the insulating material and the size of the overlapping area between the first copper bar unit and the second copper bar unit.

[0024] In a possible embodiment, when the unidirectional conductive device unit includes a diode and the switch device unit includes a MOS transistor, the number of the diodes and the number of the MOS transistors are both determined by a preset current carrying capacity of the copper busbar.

[0025] The present application sets a configuration in which the number of diodes and MOS tubes is determined by a preset current carrying capacity of the copper busbar, and then the devices are connected according to the determined number, so that the final device can achieve the purpose of miniaturization and also save costs.

[0026] In a second aspect, an embodiment of the present application provides an electronic device, comprising: a circuit board and a copper busbar as described in the first aspect and any possible embodiment thereof, wherein the copper busbar is arranged on the circuit board.

[0027] In a third aspect, an embodiment of the present application provides a method for manufacturing a copper busbar, comprising:

[0028] Soldering the first end of the unidirectional conductive device unit on the first surface of the first copper bar unit;

[0029] Welding the first end of the switch device unit to the second end of the unidirectional conductive device unit;

[0030] The second end of the switch device unit is welded to the second surface of the second copper bar unit to obtain the copper bar.

[0031] Optionally, the unidirectional conducting device unit includes a plurality of diodes, and each diode is connected in parallel, the anode of each diode constitutes the first end of the unidirectional conducting device unit, and the cathode of each diode constitutes the second end of the unidirectional conducting device unit.

[0032] Optionally, the switching device unit includes multiple metal oxide semiconductor field effect MOS transistors, each MOS tube is connected in parallel, the drain of each MOS tube constitutes the first end of the switching device unit, the source of each MOS tube constitutes the second end of the switching device unit, and the gate of each MOS tube constitutes the third end of the switching device unit.

[0033] Optionally, the method further includes:

[0034] An input reference signal lead-out line is led out from the first end of the switching device unit, and a drive signal reference lead-out line is led out from the second end of the switching device unit; the voltage between the first end and the second end of the switching device unit is detected by the input reference signal lead-out line and the drive signal reference lead-out line.

[0035] Optionally, the method further includes:

[0036] The gap between the first copper bar unit and the second copper bar unit except the one-way conductive device unit and the switch device unit is filled with insulating material.

[0037] Optionally, the total area of ​​the insulating material is larger than the area of ​​the spatial overlap region of the first copper bar unit and the second copper bar unit.

[0038] Optionally, when the unidirectional conductive device unit includes a diode and the switch device unit includes a MOS transistor, the number of the diodes and the number of the MOS transistors are both determined by a preset current carrying capacity of the copper busbar.

[0039] For the technical effects that may be achieved by the electronic device disclosed in the second aspect and the copper busbar manufacturing method disclosed in the third aspect, please refer to the technical effects that may be achieved by the first aspect or various possible solutions in the first aspect, and will not be repeated here.

[0040] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 A schematic diagram of the structure of a copper busbar provided in an embodiment of the present application;

[0043] Figure 2 A schematic structural diagram of a unidirectional conductive device unit 103 provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the structure of the switch device unit 104 provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the structure of a copper busbar provided in an embodiment of the present application;

[0046] Figure 5 A schematic diagram of the structure of a copper busbar provided in an embodiment of the present application;

[0047] Figure 6 A schematic diagram of the structure of a copper busbar provided in an embodiment of the present application;

[0048] Figure 7 A schematic flow chart of a method for manufacturing a copper busbar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to enable ordinary persons in the art to better understand the technical solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0050] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0051] In the prior art, copper busbars are long strip conductors made of pure copper, which have excellent electrical conductivity and good mechanical strength. The main function of copper busbars is to be used as conductors for large current transmission. When current passes through the copper busbar, due to the low resistance of copper, the current can pass smoothly without generating excessive heat. This makes copper busbars very efficient and reliable in large current transmission.

[0052] Copper busbars are widely used in power systems, industrial automation, transportation, home appliances, data centers and other fields due to their excellent electrical conductivity and mechanical strength. For example, copper busbars can be directly crimped onto mechanical relays by bolts, so that the contacts of the relays are in the form of copper busbars, which is suitable for large currents. However, this method requires numerous wiring harnesses, huge structural layout space, and a complicated installation process, which is not conducive to the miniaturization and wirelessization of the components.

[0053] To this end, the embodiments of the present application provide a copper busbar, a method for manufacturing the copper busbar, and an electronic device, by setting a unidirectional conductive device unit to be connected to a switch device unit, and after the connection, it is located between the first copper busbar unit and the second copper busbar unit, and the device characteristics of the switch device unit itself are used to control the entirety to be in an on state or an off state. When the switch device unit is in the on state, the direction of the overall current is controlled by the device characteristics of the unidirectional conductive device unit itself. Furthermore, by setting a simple connection between the devices, the purpose of miniaturization of the device can be achieved.

[0054] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0055] An embodiment of the present application provides a copper busbar, such as Figure 1As shown, it includes: a first copper bar unit 101, a second copper bar unit 102, a unidirectional conductive device unit 103 and a switch device unit 104. The first end 103-1 of the unidirectional conductive device unit 103 is connected to the first copper bar unit 101, the second end 103-2 of the unidirectional conductive device unit 103 is connected to the first end 104-1 of the switch device unit 104, the second end 104-2 of the switch device unit 104 is connected to the second copper bar unit 102, and the third end 104-3 of the switch device unit 104 is connected to the external controller 105.

[0056] The controller 105 may send a control signal to the switch device unit 104, and the switch device unit 104 determines whether it is in an on state or an off state after receiving the control signal. Furthermore, when the switch device unit 104 is in an on state, the unidirectional conductive device unit 103 may control the current of the first copper bar unit 101 to flow to the second copper bar unit 102.

[0057] For example, when the switching device unit 104 is a metal oxide semiconductor field effect (MOS) transistor, the control signal sent by the controller 105 can be a driving current signal; when the switching device unit 104 is a plurality of insulated gate bipolar transistors (IGBT), the control signal sent by the controller 105 can be a driving voltage signal.

[0058] Optionally, the first copper bar unit 101 is an input copper bar, and the second copper bar unit 102 is an output copper bar. It should be noted that the specific connection relationship between the first copper bar unit 101, the second copper bar unit 102, the unidirectional conductive device unit 103 and the switch device unit 104 is only exemplified here, and the present application does not limit the specific connection relationship between each end of each device. And according to the different connection relationship combinations of each end of each device of the first copper bar unit 101, the second copper bar unit 102, the unidirectional conductive device unit 103 and the switch device unit 104, the first copper bar unit 101 can also be an output copper bar, and the second copper bar unit 102 can also be an input copper bar.

[0059] Exemplarily, the unidirectional conductive device unit 103 and the switch device unit 104 can be integrated on the same chip or on different chips. Both the unidirectional conductive device unit 103 and the switch device unit 104 can be cooled by the first copper bar unit 101 and the second copper bar unit 102, so that the device service life is increased.

[0060] In one embodiment of the present application, Figure 2 As shown, the unidirectional conductive device unit 103 may include a plurality of diodes (eg Figure 21, 106-2, ..., 106-n, where n is a positive integer), and each diode is connected in parallel. The anode of each diode constitutes the first end 103-1 of the unidirectional conductive device unit 103, and the cathode of each diode constitutes the second end 103-2 of the unidirectional conductive device unit 103. For example, the anodes of the diodes 106-1, 106-2, ..., and 106-n constitute the first end 103-1 of the unidirectional conductive device unit 103, and the cathodes of the diodes 106-1, 106-2, ..., and 106-n constitute the second end 103-2 of the unidirectional conductive device unit 103.

[0061] Here, when the unidirectional conductive device unit 103 includes diodes, the number of diodes can be determined according to the preset current carrying capacity of the copper busbar. For example, the unidirectional conductive device unit 103 can include one diode or multiple diodes. In order to save costs, the minimum diode device can be used when carrying the preset current carrying capacity.

[0062] It should be noted that the unidirectional conductive device unit 103 is merely an example of being composed of a diode, and the present application does not limit the specific device composition of the unidirectional conductive device unit 103 , and any device that can achieve the unidirectional conductive function falls within the protection scope of the present application.

[0063] In one embodiment of the present application, Figure 3 As shown, the switch device unit 104 may include a plurality of MOS transistors (eg Figure 3 The MOS transistors 107-1, MOS transistor 107-2, ..., MOS transistor 107-m shown, where m is a positive integer), are connected in parallel. The drain of each MOS transistor constitutes the first end 104-1 of the switch device unit 104, the source of each MOS transistor constitutes the second end 104-2 of the switch device unit 104, and the gate of each MOS transistor constitutes the third end 104-3 of the switch device unit 104. For example, the drains of the MOS transistors 107-1, MOS transistor 107-2, ..., and MOS transistor 107-m constitute the first end 104-1 of the switch device unit 104, the sources of the MOS transistors 107-1, MOS transistor 107-2, ..., and MOS transistor 107-m constitute the second end 104-2 of the switch device unit 104, and the gates of the MOS transistors 107-1, MOS transistor 107-2, ..., and MOS transistor 107-m constitute the third end 104-3 of the switch device unit 104.

[0064] Here, when the switch device unit 104 includes a MOS transistor, the number of the MOS transistors can be determined according to the preset current carrying capacity of the copper busbar. For example, the switch device unit 104 can include one MOS transistor or multiple MOS transistors. In order to save costs, the minimum MOS transistor devices can be used when carrying the preset current carrying capacity.

[0065] Furthermore, since the structure of the MOS tube includes a parasitic diode, the parasitic diode may cause the anti-reverse failure of the overall copper busbar, so by connecting the unidirectional conduction device unit 103 and the MOS tube, both the unidirectional conduction function and the circuit switch function can be realized. It should be noted that the MOS tube is not limited to be P-type or N-type.

[0066] Optionally, the switch device unit 104 may also include a plurality of IGBT tubes, each of which is also connected in parallel. The collector of each IGBT tube constitutes the first end 104-1 of the switch device unit 104, the emitter of each IGBT tube constitutes the second end 104-2 of the switch device unit 104, and the base of each IGBT tube constitutes the third end 104-3 of the switch device unit 104.

[0067] It should be noted that the switch device unit 104 is only composed of a MOS tube or an IGBT tube for example, and the present application does not limit the specific device composition of the switch device unit 104. Any device that can realize the switching function belongs to the protection scope of the present application.

[0068] In one embodiment of the present application, Figure 4 As shown, when the unidirectional conductive device unit 103 includes a diode 106-1 and the switch device unit 104 includes a MOS transistor 107-1, the cathode of the diode 106-1 is connected to the drain of the MOS transistor 107-1, the anode of the diode 106-1 is connected to the first copper bar unit 101, the source of the MOS transistor 107-1 is connected to the second copper bar unit 102, and the gate of the MOS transistor 107-1 is connected to the controller 105.

[0069] In one embodiment of the present application, Figure 5 As shown, the copper busbar may further include: an input reference signal lead 108 and a drive signal reference lead 109. The input reference signal lead 108 is a lead from the first end 104-1 of the switch device unit 104, and the drive signal reference lead 109 is a lead from the second end 104-2 of the switch device unit 104. The input reference signal lead 108 and the drive signal reference lead 109 may be used to detect the voltage between the first end 104-1 and the second end 104-2 of the switch device unit 104.

[0070] Furthermore, when the voltage value between the first end 104-1 and the second end 104-2 of the switching device unit 104 is greater than a preset voltage value, the switching device unit 104 can be determined to be in an off state through a control signal sent by the controller 105, so as to timely adjust the voltage value between the first end 104-1 and the second end 104-2 of the switching device unit 104.

[0071] Here, since when the unidirectional conductive device unit 103 is in the on state, the potentials of the first end 103-1 of the unidirectional conductive device unit 103, the second end 103-2 of the unidirectional conductive device unit 103, and the first end 104-1 of the switching device unit 104 are the same, the input reference signal lead line 108 can also be a lead line extending from the first end 103-1 of the unidirectional conductive device unit 103.

[0072] In one embodiment of the present application, Figure 6 As shown, the gap between the first copper bar unit 101 and the second copper bar unit 102, except for the unidirectional conductive device unit 103 and the switch device unit 104, is filled with an insulating material 110. Optionally, the total area of ​​the insulating material 110 is larger than the area of ​​the spatial overlap region of the first copper bar unit 101 and the second copper bar unit 102 to ensure electrical safety between the first copper bar unit 101 and the second copper bar unit 102.

[0073] In one embodiment of the present application, an electronic device is further provided, comprising: a circuit board and a copper busbar provided in any of the above embodiments, wherein the copper busbar is arranged on the circuit board.

[0074] In one embodiment of the present application, Figure 7 As shown, a method for manufacturing a copper busbar is also provided, comprising the following steps:

[0075] S701, welding a first end of a unidirectional conductive device unit on a first surface of a first copper bar unit;

[0076] S702, welding the first end of the switch device unit to the second end of the unidirectional conductive device unit;

[0077] S703, welding the second end of the switch device unit to the second surface of the second copper busbar unit to obtain a copper busbar.

[0078] Exemplarily, the lead wires of the unidirectional conductive device unit or the switch device unit may be connected to the first copper bar unit and the second copper bar unit respectively through a wire binding process.

[0079] Optionally, the unidirectional conducting device unit includes a plurality of diodes, and each diode is connected in parallel, the anode of each diode constitutes the first end of the unidirectional conducting device unit, and the cathode of each diode constitutes the second end of the unidirectional conducting device unit.

[0080] Optionally, the switching device unit includes multiple metal oxide semiconductor field effect MOS transistors, each MOS tube is connected in parallel, the drain of each MOS tube constitutes the first end of the switching device unit, the source of each MOS tube constitutes the second end of the switching device unit, and the gate of each MOS tube constitutes the third end of the switching device unit.

[0081] Optionally, the method further includes:

[0082] An input reference signal lead-out line is led out from the first end of the switching device unit, and a drive signal reference lead-out line is led out from the second end of the switching device unit; the voltage between the first end and the second end of the switching device unit is detected by the input reference signal lead-out line and the drive signal reference lead-out line.

[0083] Optionally, the method further includes:

[0084] The gap between the first copper bar unit and the second copper bar unit except the one-way conductive device unit and the switch device unit is filled with insulating material.

[0085] Optionally, the total area of ​​the insulating material is larger than the area of ​​the spatial overlap region of the first copper bar unit and the second copper bar unit.

[0086] Optionally, when the unidirectional conductive device unit includes a diode and the switch device unit includes a MOS transistor, the number of the diodes and the number of the MOS transistors are both determined by a preset current carrying capacity of the copper busbar.

[0087] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A copper busbar, characterized in that: The copper bar comprises: a first copper bar unit, a second copper bar unit, a unidirectional conductive device unit and a switch device unit; the first end of the unidirectional conductive device unit is connected to the first copper bar unit, the second end of the unidirectional conductive device unit is connected to the first end of the switch device unit, and the second end of the switch device unit is connected to the second copper bar unit; the third end of the switch device unit is connected to an external controller; The switch device unit is used to determine whether it is in an on state or an off state through the control signal sent by the controller; The one-way conductive device unit is used to control the current of the first copper bar unit to flow to the second copper bar unit when the switch device unit is in an on state.

2. The copper busbar according to claim 1, characterized in that: The unidirectional conductive device unit includes a plurality of diodes, and each of the diodes is connected in parallel, an anode of each of the diodes constitutes a first end of the unidirectional conductive device unit, and a cathode of each of the diodes constitutes a second end of the unidirectional conductive device unit.

3. The copper busbar according to claim 1, characterized in that: The switch device unit includes a plurality of metal oxide semiconductor field effect MOS transistors, each of which is connected in parallel, the drain of each of which constitutes a first end of the switch device unit, the source of each of which constitutes a second end of the switch device unit, and the gate of each of which constitutes a third end of the switch device unit.

4. The copper busbar according to claim 1, characterized in that: The copper busbar also includes: Input reference signal lead wire and drive signal reference lead wire; The input reference signal lead wire is a lead wire led out from the first end of the switch device unit, and the drive signal reference lead wire is a lead wire led out from the second end of the switch device unit; The input reference signal lead wire and the drive signal reference lead wire are used to detect the voltage between the first end and the second end of the switch device unit.

5. The copper busbar according to claim 4, characterized in that: The switch device unit is specifically used to determine that it is in an off state through a control signal sent by the controller when the voltage value between the first end and the second end of the switch device unit is greater than a preset voltage value.

6. The copper busbar according to claim 1, characterized in that: The gap between the first copper bar unit and the second copper bar unit except the one-way conductive device unit and the switch device unit is filled with insulating material.

7. The copper busbar according to claim 6, characterized in that: The total area of ​​the insulating material is larger than the area of ​​the spatial overlap region of the first copper bar unit and the second copper bar unit.

8. The copper busbar according to claim 2 or 3, characterized in that: When the one-way conducting device unit includes a diode and the switch device unit includes a MOS transistor, the number of the diodes and the number of the MOS transistors are both determined by the preset current carrying capacity of the copper busbar.

9. An electronic device, characterized in that: include: A circuit board and a copper busbar as claimed in any one of claims 1 to 8, wherein the copper busbar is arranged on the circuit board.

10. A method for manufacturing a copper busbar, characterized in that: include: Soldering the first end of the unidirectional conductive device unit on the first surface of the first copper bar unit; Welding the first end of the switch device unit to the second end of the unidirectional conductive device unit; The second end of the switch device unit is welded to the second surface of the second copper bar unit to obtain the copper bar.

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