Terminal structure, power converter, and method for manufacturing the terminal structure

Abstract

The present invention provides a terminal structure, a power converter, and a method for manufacturing the terminal structure that can improve the adhesion of the terminals and suppress the impact on the lower part of the terminals. [Solution] The terminal structure TS comprises a first terminal T1 having a welding surface WS, and a second terminal T2 welded to the first terminal T1 on the opposite side of the welding surface WS. The second terminal T2 is welded in a state where it is folded in two or more layers.

Description

Technical Field

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[0001] The present disclosure relates to a terminal structure, a power conversion device, and a method for manufacturing the terminal structure.

Background Art

[0002] A power conversion device that receives energy from a power source such as a battery and drives a motor or the like, which is used in in-vehicle devices such as electric vehicles, is required to be miniaturized and highly efficient while performing high-power control necessary for increasing the output. For this reason, the metal terminals of a plurality of power modules mounted to control high power are electrically connected to other electronic components in the power conversion device, such as the metal terminals of a capacitor, a motor, a battery, and the like. Further, when the terminals of components cannot be directly connected to each other, the component terminals are connected by a metal bus bar or the like. For this connection, stable quality is required so that heat is not generated due to connection resistance at the connection portion during high-current energization, and breakage does not occur due to aging factors such as vibration or corrosion during use, mainly in in-vehicle devices. As such a connection method, welding techniques such as laser in an overlapping shape have been studied.

[0003] For example, International Publication No. 2021-084914 (Patent Document 1) describes a structure in which a circuit board and a power supply terminal connected thereto are arranged one above the other and welded at a welding portion provided at the center of the terminal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the structure described in the above-mentioned document, dimensional variations exist in each component, resulting in misalignment of the terminals relative to the substrate during assembly. This leads to misalignment of the terminals relative to the reference position on the substrate, and a gap between the substrate and the terminals. Consequently, variations in the gap between the substrate and the terminals exist. Therefore, it is difficult to improve the adhesion of the terminals. Furthermore, to account for the variations in the gap between the substrate and the terminals, the irradiation energy during welding is set higher than necessary. As a result, the irradiation energy becomes excessive, causing the lower terminal to melt too much. This leads to melt-through of the molten portion and penetration of the irradiation energy, affecting the lower part of the terminal.

[0006] This disclosure has been made in view of the above-mentioned problems, and its purpose is to provide a terminal structure, a power converter, and a method for manufacturing a terminal structure that can improve the adhesion of the terminals and suppress the influence on the lower part of the terminals. [Means for solving the problem]

[0007] The terminal structure of this disclosure comprises a first terminal having a welded surface and a second terminal welded to the first terminal on the opposite side of the welded surface. The second terminal is welded in a state where it is folded in two or more layers. [Effects of the Invention]

[0008] The terminal structure of this disclosure makes it possible to improve the adhesion of the terminals and suppress the impact on the lower part of the terminals. [Brief explanation of the drawing]

[0009] [Figure 1] This is an electrical circuit diagram of the power conversion device according to Embodiment 1. [Figure 2] This is an external view of the power conversion device according to Embodiment 1. [Figure 3] This is a diagram illustrating the terminal shape of the power converter according to Embodiment 1. [Figure 4] This diagram shows the state of welding the power conversion device according to Embodiment 1. [Figure 5]This is a diagram showing the power module of the power conversion device according to Embodiment 1. [Figure 6] This is an enlarged view of the terminal portion of the power converter according to Embodiment 1. [Figure 7] This figure shows the state in which the upper terminal of the power converter according to Embodiment 1 is pushed down from the top of the terminal to reduce the gap between it and the lower terminal. [Figure 8] This is an enlarged view showing the state of the terminal structure according to Embodiment 1 before the terminal is pushed down from the top during assembly. [Figure 9] This figure shows the state in which, during the assembly of the terminal structure according to Embodiment 1, the terminal is pushed down from above, and the gap between it and the lower terminal is absorbed by the spring properties of the terminal, resulting in improved contact. [Figure 10] Figure (a) shows the terminal structure according to Embodiment 1 as viewed from above, before the upper and lower terminals make contact, and Figure (b) shows the state after the terminals make contact, the terminal angle changes due to the spring action, and the lower terminal becomes visible from above. [Figure 11] This is a flowchart showing a method for manufacturing a terminal structure according to Embodiment 1. [Figure 12] This figure shows a state in which a terminal position detection unit indicating the position of the terminal is provided on the side of the terminal, which is bent to give it spring properties, the lower terminal of the terminal structure according to Embodiment 2. [Figure 13] Figure (a) shows the terminal position detection unit before the upper and lower terminals make contact, as viewed from the terminal-shaped part of the terminal structure according to Embodiment 2, and Figure (b) shows the terminal position detection unit in the state where the upper terminal is pushed down to absorb the gap and the upper and lower terminals are in close contact. [Figure 14] Figure (a) shows the terminal position detection unit of the terminal structure according to Embodiment 2, with the terminal position detection unit provided at the tip, before the upper and lower terminals come into contact, and Figure (b) shows the terminal position detection unit in a state where the upper and lower terminals are in close contact. [Figure 15] This figure shows a state in which a terminal position adjustment recess is provided on the upper terminal so that the horizontal position misalignment of the terminal structure according to Embodiment 3 can be corrected. [Figure 16]This is a diagram showing a state in which a convex portion for terminal position adjustment is provided on a lower terminal so as to correct a horizontal displacement of the terminal structure according to Embodiment 3. [Figure 17] This is a diagram showing a state before the concave portion for terminal position adjustment and the convex portion for terminal position adjustment mesh with each other to correct the horizontal displacement of the terminal structure according to Embodiment 3, and the upper terminal is pushed down. [Figure 18] This is a diagram showing a state in which the upper terminal is pushed down so that the lower terminal can be seen from above the upper terminal to correct the horizontal displacement of the terminal structure according to Embodiment 3. [Figure 19] This is a diagram showing a modified example in which the concave portion for terminal position adjustment and the convex portion for terminal position adjustment for correcting the horizontal displacement of the terminal structure according to Embodiment 3 are formed in a triangular prism shape. [Figure 20] FIG. (a) shows an upper terminal provided with an inclination that matches the inclination of the lower terminal when the upper and lower terminals of the terminal structure according to Embodiment 4 are in close contact, FIG. (b) shows a state of the upper and lower terminals in close contact as viewed obliquely from below, and FIG. (c) shows a state of the upper and lower terminals in close contact as viewed from the side. [Figure 21] This is a diagram showing a terminal shape in which the upper and lower terminals are made more parallel when the upper terminal is pushed down and the upper and lower terminals are brought into close contact by curving the bent portion of the terminal of the terminal structure according to Embodiment 5. [Figure 22] [[ID=|18]]FIG. (a) shows a state before pushing down of a terminal shape provided with a structure for hooking a protruding portion when the upper terminal is pushed down by providing an upward protrusion at the tip of the lower terminal of the terminal structure according to Embodiment 6, and FIG. (b) shows a state after pushing down and fixing to facilitate determination of the pushed-down state and be able to fix the pushed-down state.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described with reference to the drawings. In the following, the same or corresponding parts will be denoted by the same reference numerals, and duplicate descriptions will not be repeated.

[0011] [[ID=3|0]]Embodiment 1. The power conversion device 1 according to Embodiment 1 will be described below with reference to the drawings.

[0012] Figure 1 is a basic circuit diagram of the power converter 1. Referring to Figure 1, the power converter 1 is equipped with multiple electronic components. In this embodiment, the power converter 1 is equipped with multiple electronic components including a battery 5, a motor 6, a sensor 7, a control board 8, a power module 10, and a capacitor 60. The wiring between each electronic component is connected by metal busbars or cables. The power converter 1 receives power from an externally located battery 5. The supplied power is stabilized by electronic components such as the capacitor 60 before being supplied to the power module 10. The power module 10, which has a large current flowing when energized and generates a large amount of heat during power control, is connected to a heat dissipation unit 3 (see Figure 2), and dissipates heat to the outside of the power converter 1 through this heat dissipation unit 3. In addition to dissipating heat into the air, some heat dissipation units 3 also circulate cooling water inside, but the details are omitted as they are not relevant to this embodiment. The control terminals of the power module 10 are connected to a control board 8 that outputs control signals for turning the current on and off. The power module 10 outputs the supplied power to the motor 6 according to the control signal, driving the motor 6. Since the motor 6 is usually driven in three phases, it contains three coils. The output current is detected by the sensor 7. The control board 8, upon receiving the detected value, corrects it so that the detected value matches the target output value when driving the motor 6, and then outputs an on / off control signal for the power module 10.

[0013] Figure 2 is an external view of the power converter 1 according to Embodiment 1. Referring to Figure 2, the battery 5 and motor 6 (see Figure 1), which are located outside the power converter 1, are not shown for the sake of clarity. The power converter 1 is equipped with a housing 2 made of metal or resin for waterproofing and to prevent damage. In Figure 2, the side of the housing 2 is not shown for clarity. The power converter 1 is equipped with a heat dissipation section 3 to release internal heat generated by heat generation in parts where large currents flow. The heat dissipation section 3 dissipates heat to the outer wall portion of the power converter 1, and water or air may be circulated to improve heat dissipation efficiency. The power supplied from the battery 5 shown in Figure 1 is subjected to waveform stabilization such as noise reduction by a capacitor 60 or other electronic components, and then supplied to the power module 10 through the electronic component terminal 61 coming out of the capacitor 60 and the module PN terminal 13 of the power module 10 connected thereto. The power module 10 receives control signals from the control board 8 (see Figure 1) at the module control terminal 11 and performs on / off control of the supplied power. When the power module is ON, the supplied power is received at the module's AC terminal 12, passes through the power module 10, and is supplied to the motor-side busbar unit 50 via the motor-side busbar terminal 51 connected to the end of the module's AC terminal 12. This power then drives the motor 6 connected further down the line. When the power module is OFF, the output is stopped, and the power module 10 does not supply power to the motor 6. Because a large current of several hundred amperes flows through the power module 10 when the circuit is operating, the amount of heat generated is large due to the resistance when energized and the losses during on / off switching, resulting in high temperatures. Therefore, the power module 10 is in close contact with the aforementioned heat dissipation section 3, and is designed to dissipate heat to the outside.

[0014] Multiple electronic components are connected by a terminal structure TS. The terminal structure TS comprises a first terminal T1 and a second terminal T2. In this embodiment, the motor-side busbar terminal 51 corresponds to the first terminal T1, and the module AC terminal 12 corresponds to the second terminal T2. Also, the electronic component terminal 61 corresponds to the first terminal T1, and the module PN terminal 13 corresponds to the second terminal T2. The first terminal T1 has a welding surface WS. The welding surface WS is the surface to which the welding laser 40 (see Figure 3) is irradiated. The second terminal T2 is welded to the first terminal T1 on the opposite side of the welding surface WS. The second terminal T2 is welded in a folded state of two or more layers. In its folded state, the second terminal T2 has an upper layer located on the top and a lower layer located on the bottom. In this embodiment, the second terminal T2 is folded into two layers. The second terminal T2 may be folded into three or more layers.

[0015] When looking at the motor-side busbar terminal 51 from the welding mask WS, the tip of the module AC terminal 12 protrudes from the motor-side busbar terminal 51. Also, when looking at the electronic component terminal 61 from the welding mask WS, the tip of the module PN terminal 13 protrudes from the electronic component terminal 61. In other words, when looking at the first terminal T1 from the welding mask WS, the tip of the second terminal T2 protrudes from the first terminal T1.

[0016] The thickness of the motor-side busbar terminal 51 is greater than the thickness of the module AC terminal 12. Also, the thickness of the electronic component terminal 61 is greater than the thickness of the module PN terminal 13. In other words, the thickness of the first terminal T1 is greater than the thickness of the second terminal T2.

[0017] Figure 3 shows the state in which the tips of the module AC terminal 12 and module PN terminal 13 are bent at a certain angle and a terminal spring portion 14 is provided. In Figure 3, the angle of the terminal spring portion 14 is a large angle of about 45 degrees for clarity, but this angle can be set to an angle more suitable for the arrangement of the components, and a specific angle is not required. Since this terminal spring portion 14 is created by bending the original lower plate, the terminal plate appears double-layered when viewed from above. In the power converter 1 having the power module 10 shown in Embodiment 1, the motor-side busbar terminal 51 and electronic component terminal 61 on the upper side are adjusted in height so that they are in contact with the tip of the terminal spring portion 14.

[0018] Figure 4 shows the state in which the busbars located inside the power converter 1 are connected. As mentioned above, there are two main types of connections for the terminals of the power module 10. The first part is a combination of module PN terminal 13 and electronic component terminal 61, which are connected to the battery 5 (see Figure 1) and electronic components such as capacitor 60. The second part is a combination of module AC terminal 12 and motor-side busbar terminal 51, which are connected to the motor 6 (see Figure 1). At this time, the terminals are stacked vertically. From the standpoint of attaching to the heat dissipation section 3 of the power module 10 and ease of assembly, the module AC terminal 12 and module PN terminal 13 have thinner plates and are located on the bottom. The electronic component terminal 61 and motor-side busbar terminal 51, which have no production or structural constraints, are attached later and are located on the top, and have thicker plates to suppress heat generation due to resistance. The upper and lower terminals are connected by melting the metal in the area where the thin lower plate and thick upper plate overlap.

[0019] The terminals, which are stacked vertically, are made of metal such as copper or aluminum. Energy is irradiated onto the overlapping metal portion of the upper and lower terminals, melting the metals and connecting the terminals. There are no restrictions on the method of supplying energy; in addition to simple heating, methods such as sparking (TIG - Tungsten Inert Gas) and electron beams are used. However, in this embodiment, we will explain using laser light, which has been frequently used in recent years. During laser welding, a laser output device 31 is installed on top of the power converter 1 installed inside the welding machine. The laser output device 31 is configured to output a welding laser 40. In addition, a terminal condition inspection device 32 is installed to check the position and contact state of each terminal using a camera or the like. Multiple terminal condition inspection devices 32 may be arranged not only from above, but also from the side and at an angle, but the number and angles are not relevant to the explanation of the effects of this embodiment, so details are omitted.

[0020] Figure 5 is an enlarged view of a single power module 10. Figure 6 shows an enlarged view of the bent portion of the module AC terminal 12. In this embodiment, the module AC terminal 12 and module PN terminal 13 are rectangular parallelepiped plates with a rectangular cross-section and a flat top. The cross-sections of the module AC terminal 12 and module PN terminal 13 may be trapezoidal, rhombic, elliptical, or other special cross-sections. The module AC terminal 12 and module PN terminal 13 are bent at a terminal bending portion 16 located at a certain distance from the tip, and have a terminal spring portion 14 in the shape of a plate at the end of this portion. In Figure 6, the terminal spring portion 14 is a straight plate, but it may be a moderately curved surface or the like. When force is applied from above to this terminal spring portion 14, the bending angle of the terminal bending portion 16 changes according to the force. The terminal spring portion 14 is structured to absorb the force from above while deforming to change its angle, thereby suppressing the impact on the module AC terminal 12 below.

[0021] Referring to Figure 7, the connection in the state where Embodiment 1 is applied will be described. Even when Embodiment 1 is applied, at the assembly stage, variations in the contact between terminals occur depending on the terminal position during assembly. Therefore, in order to improve the contact between terminals, the motor-side busbar terminal 51 and the electronic component terminal 61, which are the upper terminals, are pressed downward using the chuck jig 30. The pressed terminals are bent downward, and the gap between terminals is reduced. In Embodiment 1, the terminals are provided with a terminal bending portion 16. Therefore, when the upper terminal is pressed down by the chuck jig 30, the tip of the terminal spring portion 14 comes into contact with the back surface of the upper terminal, and as it is pressed further down, the angle changes. Eventually, the back surface of the upper terminal and the terminal spring portion 14 become closer to parallel. When it is confirmed that the contact is sufficient within a certain range, the pressing down of the chuck jig 30 stops. As a result, even if the state of each terminal differs at the time of assembly, the contact between terminals can be made uniform by the deformation of the terminal spring portion 14 and the amount of pressing down of the chuck jig 30. The same applies to the bent portion of the module PN terminal 13, which has a similar shape except for the terminal width.

[0022] Referring to Figure 8, the module AC terminal 12 will be explained in detail. Below is the module AC terminal 12 to which Embodiment 1 is applied, and above is the motor-side busbar terminal 51. The module AC terminal 12 is bent at the terminal bending portion 16, and the terminal spring portion 14 is positioned at the end of it. Figure 8 shows the state before the chuck jig 30 pushes down the module AC terminal 12. As a result, the highest point of the terminal spring portion 14 of the lower terminal is either separated from the back surface of the module AC terminal 12 of the upper terminal or in slight contact with it. In this state, the tip of the terminal spring portion 14 is completely below the module AC terminal 12, so the tip of the terminal spring portion 14 cannot be seen from above the module AC terminal 12 and cannot be detected by the terminal condition inspection device 32 or the like.

[0023] Figure 9 shows the state in which the chuck jig 30 pressurizes and pushes down the motor-side busbar terminal 51 from the state in Figure 8. The chuck jig 30 pushes down the motor-side busbar terminal 51, causing the motor-side busbar terminal 51 to contact the terminal spring portion 14. As the motor-side busbar terminal 51 is pushed down further, the bending angle of the terminal bending portion 16 increases, the angle of the terminal spring portion 14 changes, the module AC terminal 12 and the terminal spring portion 14 become more parallel, and the distance (gap) between the terminals decreases. Furthermore, as the bending angle of the terminal spring portion 14 changes, the tip of the terminal spring portion 14 extends, and the terminal spring portion 14 becomes visible beyond the tip of the motor-side busbar terminal 51. For example, if the length of the terminal spring portion 14 is 10 mm and the initial angle is 15°, the horizontal length of the terminal spring portion 14 will change as follows depending on the change in angle. When the initial angle is 15°, the horizontal length of the terminal spring portion 14 is approximately 9.66 mm (10cos15°≈9.66 mm). When the angle is 10°, the horizontal length of the terminal spring portion 14 is approximately 9.85 mm (10cos10°≈9.85 mm). When the angle is 5°, the horizontal length of the terminal spring portion 14 is approximately 9.96 mm (10cos5°≈9.96 mm). In this way, the horizontal length of the terminal spring portion 14 changes as the terminal is pressed down. By pre-determining the terminal length by adjusting for the expected variation in the distance between terminals during assembly and the horizontal length of this terminal, the terminal spring portion 14 is not visible from above the motor-side busbar terminal 51 at the time of assembly, and becomes visible when the terminals are sufficiently in contact. The chuck jig 30 pushes down the motor-side busbar terminal 51 until the terminal spring portion 14 is visible, and stops pushing down once it is visible a certain distance. This allows for consistent contact and prevents welding from starting in a non-contact state. In this state, the welding laser 40 is irradiated towards the welding portion 41 located directly above the contact area, melting the upper and lower metals to connect the terminals and stabilize the welding state. The lower terminal is bent as described above. For this reason, the module AC terminal 12 is arranged in two tiers, one above the other.Even if excessive energy is irradiated due to variations in the output of the welding laser 40, the presence of another terminal prevents the welding laser 40 from irradiating the lower part of the power module 10 through the terminal spring portion 14.

[0024] Figure 10 shows this state as viewed from above the motor-side busbar terminal 51. As shown in Figure 10(a), before the chuck jig 30 pushes down the motor-side busbar terminal 51, the tip of the terminal spring portion 14 is not visible from above. As shown in Figure 10(b), when the chuck jig 30 pushes down the motor-side busbar terminal 51, the tip of the terminal spring portion 14 becomes visible from above. After this state is reached, the welding laser 40 is irradiated onto the welding area 41, and the terminals are connected by welding. At this time, visibility can be further improved if the terminal of the terminal spring portion 14 is painted a different color from the lower row of the module AC terminal 12.

[0025] Based on the above, the method for manufacturing the terminal structure TS according to Embodiment 1 can be summarized as follows, with reference to Figure 11.

[0026] The manufacturing method for the terminal structure TS according to Embodiment 1 comprises a pressing step (S1) and a welding step (S2). In the pressing step S1, a first terminal T1 having a welding surface WS is pressed against a second terminal T2 which is folded in two or more layers and is positioned on the opposite side of the welding surface WS, promoting the bending of the second terminal T2 until the tip of the second terminal T2 protrudes from the first terminal T1 when viewed from the welding surface WS. In the welding step S2, with the tip of the second terminal T2 protruding from the first terminal T1 when viewed from the welding surface WS, the first terminal T1 and the second terminal T2 are welded together from the welding surface WS of the first terminal T1.

[0027] Next, the effects and advantages of Embodiment 1 will be described. According to the terminal structure TS of Embodiment 1, the module AC terminal 12 and module PN terminal 13, which correspond to the second terminal T2, are welded in a state where they are folded in two or more layers. Therefore, the second terminal T2 has a springy shape. Thus, the gap between terminals that occurs during assembly can be absorbed by the springy portion of the second terminal T2. As a result, the contact between terminals can be improved.

[0028] Furthermore, since the second terminal T2 has two stages, even if the irradiation energy of the welding laser 40 becomes excessive and the upper stage of the second terminal T2 becomes excessively melted, the lower stage of the second terminal T2 can suppress the molten portion from falling to the bottom of the terminal and the irradiation of the welding laser 40 to the bottom of the terminal. Therefore, the impact on the bottom of the terminal can be suppressed.

[0029] According to the terminal structure TS of Embodiment 1, when viewing the motor-side busbar terminal 51 and electronic component terminal 61 corresponding to the first terminal T1 from the welding surface WS, the tip of the second terminal T2 protrudes from the first terminal T1. Therefore, when the terminals are pressed down to reduce the gap in order to bring them into close contact during connection, the angle of the deformed part changes due to the spring action, making the tip of the second terminal T2 visible from the bottom of the first terminal T1. Thus, the contact between the terminals can be visually confirmed. This makes it possible to determine that the terminals are in sufficient contact.

[0030] According to the terminal structure TS of Embodiment 1, the thickness of the first terminal T1 is greater than the thickness of the second terminal T2. From the viewpoint of attachment to the heat dissipation section 3 of the power module 10 and ease of assembly, the module AC terminal 12 and module PN terminal 13 have thinner plates. The electronic component terminals 61 and motor-side busbar terminals 51, which have no production or structural constraints, have thicker plates to suppress heat generation due to resistance. Therefore, ease of assembly can be improved and heat generation due to resistance can be suppressed.

[0031] According to the power converter 1 of Embodiment 1, a power module 10 and multiple electronic components such as capacitors 60 are connected by a terminal structure TS. Therefore, it is possible to provide a power converter 1 equipped with a terminal structure TS that can improve the contact between terminals and suppress the impact on the lower part of the terminals.

[0032] According to the manufacturing method of the terminal structure TS of Embodiment 1, in the pressing step S1, the first terminal T1 having a welding surface WS is pressed against the second terminal T2, which is folded in two or more layers and positioned on the opposite side of the welding surface WS, to promote the bending of the second terminal T2 until the tip of the second terminal T2 protrudes from the first terminal T1 when viewed from the welding surface WS. In the welding step S2, with the tip of the second terminal T2 protruding from the first terminal T1 when viewed from the welding surface WS, the first terminal T1 and the second terminal T2 are welded from the welding surface WS of the first terminal T1. As a result, the adhesion of the terminals can be improved and the influence on the lower part of the terminals can be suppressed.

[0033] Embodiment 2. Embodiment 2 has the same configuration, manufacturing method, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.

[0034] Figure 12 shows a configuration in which one or more terminal position detection units 15 are provided on the side surface of the lower module AC terminal 12 to more accurately detect its position. In other words, the module AC terminal 12 corresponding to the second terminal T2 includes a terminal position detection unit 15 provided on the upper side surface of the second terminal T2. The terminal position detection unit 15 extends from the first terminal T1 when viewed from the welding surface WS. The terminal position detection unit 15 protrudes from the side surface of the upper terminal when viewed from the top of the upper terminal. The terminal position detection unit 15 is provided on the terminal spring portion 14. The position of the terminal position detection unit 15 changes when the bending angle of the terminal spring portion 14 changes. It is possible to detect how much the terminal spring portion 14 has changed even before the tip of the terminal spring portion 14 becomes visible from the motor-side busbar terminal 51, which is the upper terminal. When the terminal position detection unit 15 begins to move, it can be determined that the upper and lower terminals are in contact, and the amount of change in contact allows for the determination of the bending angle of the terminal bending portion 16 and the contact state of the terminal spring portion 14.

[0035] Figure 13 shows the terminal position detection unit 15 as viewed from above the motor-side busbar terminal 51. Starting from the state shown in Figure 13(a) before the motor-side busbar terminal 51 is pushed down, as the motor-side busbar terminal 51 is pushed down and comes into close contact with the module AC terminal 12, the terminal position detection unit 15 moves toward the tip of the motor-side busbar terminal 51. As the motor-side busbar terminal 51 is pushed down further, the terminal spring portion 14 becomes visible from the tip of the motor-side busbar terminal 51, as shown in Figure 13(b). The position of the terminal position detection unit 15 may be associated with the weld portion 41, and the state in which the weld portion 41 and the terminal position detection unit 15 are aligned in a straight line may be used as a criterion for determining that welding is possible.

[0036] Furthermore, as shown in Figure 14, the terminal position detection unit 15 may be provided at the tip of the terminal spring unit 14. In the state before the motor-side busbar terminal 51 and the module AC terminal 12 make contact, as shown in Figure 14(a), only the terminal position detection unit 15 protruding from above the motor-side busbar terminal 51 is visible. When the motor-side busbar terminal 51 is pushed down and makes contact with the module AC terminal 12, the terminal spring unit 14 becomes visible from the tip of the motor-side busbar terminal 51, as shown in Figure 14(b). At this time, the terminal position detection unit 15 is visible around the motor-side busbar terminal 51. Therefore, the number of viewing directions during determination can be increased. Even in this state, since there is another terminal below the terminal spring unit 14, even if the plate material melts and falls off during welding of the terminal spring unit 14, both the upper and lower terminals will not be penetrated.

[0037] Next, the effects and advantages of Embodiment 2 will be described. According to the terminal structure TS of Embodiment 2, the terminal position detection unit 15, which is provided on the upper side surface of the module AC terminal 12 corresponding to the second terminal T2, extends from the first terminal T1 when viewed from the welding surface WS. Therefore, the contact status of the terminals can be confirmed by the change in the position of the terminal position detection unit 15.

[0038] Embodiment 3. Embodiment 3 has the same configuration, manufacturing method, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.

[0039] Referring to Figure 15, a semicircular recessed terminal position adjustment recess 21 is provided at the bottom of the motor-side busbar terminal 51, which is on the upper side during welding. Referring to Figure 16, a terminal position adjustment protrusion 20 corresponding to the terminal position adjustment recess 21 is provided at the top of the terminal spring portion 14, which is on the lower side during welding. In other words, the first terminal T1 includes the terminal position adjustment recess 21, and the second terminal T2 includes the terminal position adjustment protrusion 20. Note that either the first terminal T1 or the second terminal T2 includes either the terminal position adjustment recess 21 or the terminal position adjustment protrusion 20, and either the first terminal T1 or the second terminal T2 includes either the terminal position adjustment recess 21 or the terminal position adjustment protrusion 20. The terminal position adjustment recess 21 and the terminal position adjustment protrusion 20 interlock with each other. During assembly, the module AC terminal 12 of the power module 10 and the motor-side busbar terminal 51 and electronic component terminals 61 such as capacitors are misaligned due to a certain assembly tolerance caused by the gap between screws and screw holes or variations in materials. When the motor-side busbar terminal 51 and the module AC terminal 12 overlap in a misaligned state as shown in Figures 15 and 16, when the motor-side busbar terminal 51 is pushed down, the terminal position adjustment recess 21 and the terminal position adjustment protrusion come into contact at their ends. When the motor-side busbar terminal 51 is further pushed up in this misaligned state, the motor-side busbar terminal 51 and the module AC terminal 12 come into close contact. At that time, the upper and lower terminal position adjustment recesses 21 and terminal position adjustment protrusions correct the position so that their central axes align, and the terminal misalignment is corrected during material production or assembly.

[0040] Figure 17 shows the state before the motor-side busbar terminal 51, which is the upper terminal, is pressed down, with the motor-side busbar terminal 51 and the module AC terminal 12 superimposed. Also, when viewed from above the motor-side busbar terminal 51, the terminal spring portion 14 is located below the motor-side busbar terminal 51 and is therefore not visible. However, even if the center positions of the motor-side busbar terminal 51 and the module AC terminal 12 are slightly misaligned during assembly, the protrusion of the terminal position adjustment protrusion 20 will hit the corner of the recess of the terminal position adjustment recess 21, and the centers of the terminals will align along the slope of the protrusion, causing the protrusion to shift in the direction that it enters the recess. Furthermore, when the motor-side busbar terminal 51 is pressed down, the terminal position adjustment protrusion 20 will enter the terminal position adjustment recess 21, correcting the misalignment of the terminals and allowing them to come into close contact with each other. Also, as described above, the bending angle of the terminal changes when pressed down by the chuck jig 30, and as shown in Figure 18, the terminal spring portion 14 becomes visible from above the terminal. Therefore, it is also possible to confirm that the terminals are in a tight seal.

[0041] In the motor-side busbar terminal 51 mentioned above, the cross-section of the protrusion is semicircular, but the shape of the protrusion can be any shape that allows the centers of the upper and lower terminals to be aligned by utilizing the inclined portion or the like. As an example, Figure 19 shows a terminal position adjustment protrusion 20 and terminal position adjustment recess 21 with a triangular cross-section. When the motor-side busbar terminal 51 is pressed down, the recessed portion of the terminal position adjustment recess 21 comes into contact with the triangular inclined surface of the terminal position adjustment protrusion 20, and the position is corrected along the triangular inclined surface so that the centers of the upper and lower terminals align, allowing the upper and lower terminals to be brought into close contact. Even in this state, since there is another terminal below the terminal spring portion 14, even if the plate material melts and falls off during welding of the terminal spring portion 14, both the upper and lower terminals will not be penetrated.

[0042] Next, the effects and advantages of Embodiment 3 will be described. In the terminal structure TS according to Embodiment 3, the terminal position adjustment recess 21 and the terminal position adjustment protrusion 20 interlock with each other. Therefore, even if the center positions of the first terminal T1 and the second terminal T2 are misaligned during assembly, when the first terminal T1 is pressed down, the terminal position adjustment recess 21 and the terminal position adjustment protrusion 20 interlock, and the center positions of the first terminal T1 and the second terminal T2 coincide, thereby correcting the horizontal misalignment. Consequently, welding can be stabilized by improving the contact between the terminals.

[0043] Embodiment 4. Embodiment 4 has the same configuration, manufacturing method, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.

[0044] The above example describes a case where the motor-side busbar terminal 51 is pressed down by the chuck jig 30, changing the angle of the terminal spring portion 14 of the module AC terminal 12 of the power module 10, as an example of bringing the upper and lower terminals into close contact during welding. Ideally, the upper surface of the module AC terminal 12 and the lower surface of the motor-side busbar terminal 51 should be in close contact. However, when the motor-side busbar terminal 51 is pressed down from above by the chuck jig 30, it is not possible to make them perfectly parallel. When the tip of the motor-side busbar terminal 51 makes contact, a gap is created because there is a certain incline in the other parts. For this reason, as shown in Figure 20(a), a terminal receiving portion 22 is provided at the bottom of the motor-side busbar terminal 51, having an incline that matches the angle at which the terminal spring portion 14 of the module AC terminal 12 is pressed down to its optimal state. When the motor-side busbar terminal 51 is pressed down, the incline angles of the upper and lower terminals become the same, as shown in Figure 20(b), thus increasing the contact area. As shown in Figure 20(c), the large contact area between the terminals increases the weldable area and allows for more stable welding quality. Specifically, the first terminal T1 includes a terminal receiving portion 22 that has a slope that reduces the thickness of the first terminal T1 towards its tip. The terminal receiving portion 22 is welded to the second terminal T2.

[0045] Next, the effects and advantages of Embodiment 4 will be described. In the terminal structure TS according to Embodiment 4, the inclined terminal receiving portion 22 of the first terminal T1 is welded to the second terminal T2. Therefore, by providing the terminal receiving portion 22 with an inclination that is designed to be such that the upper terminal is pushed down and in close contact with the lower terminal, it is possible to suppress the occurrence of a gap between the upper and lower terminals. Thus, the contact between the terminals can be improved. Furthermore, by improving the contact between the terminals, the welding can be stabilized. In addition, by providing the inclined terminal receiving portion 22 of the first terminal T1, the position of the springy terminal portion of the second terminal T2 and the first terminal T1 when they are in close contact can be changed. In other words, since the initial height position of the terminals can be changed, the range of tolerance for inclination of the terminals due to assembly accuracy, etc., can be expanded.

[0046] Furthermore, even if a larger notch is made, the same effect can be obtained as long as there is sufficient thickness remaining at the tip of the motor-side busbar terminal 51.

[0047] Embodiment 5. Embodiment 5 has the same configuration, manufacturing method, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.

[0048] To further improve the contact between the upper surface of the module AC terminal 12 and the lower surface of the motor-side busbar terminal 51, if the terminal spring portion 14 is to bend completely from an inclined state, the terminal bending portion 16 needs to be bent 180 degrees. This places strong stress on the terminal bending portion 16, which may cause it to break. Therefore, as shown in Figures 21(a) and 21(b), the terminal bending portion 16 is given a bulge. In other words, the second terminal T2 includes the terminal bending portion 16. The terminal bending portion 16 is curved so as to bulge outwards. In this way, a buffer portion is provided in the terminal bending portion 16. When the motor-side busbar terminal 51 is pushed down and the terminal spring portion 14 is bent, excessive stress is not placed on the terminal bending portion 16. In this state, the lower part of the module AC terminal 12, the terminal spring portion 14, and the motor-side busbar terminal 51 are all parallel. Furthermore, since the weldable area of ​​the terminal spring portion 14 and the motor-side busbar terminal 51 can be increased, the quality during welding can be made more stable. In addition, even if the plate material of the terminal spring portion 14 melts off during welding, it can be prevented from penetrating both it and the module AC terminal 12 below it.

[0049] Next, the effects of Embodiment 5 will be described. According to the terminal structure TS of Embodiment 5, the terminal bending portion 16 of the second terminal T2 is curved so as to bulge outwards. Therefore, when the second terminal T2 is bent, the stress on the terminal bending portion 16 can be reduced.

[0050] Embodiment 6. Embodiment 6 has the same configuration, manufacturing method, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.

[0051] Figure 22(a) shows a structure in which a terminal fixing projection 18 is provided on the tip of the lower module AC terminal 12 in order to bring the upper surface of the module AC terminal 12 into close contact with the motor-side busbar terminal 51, before being pressed by the chuck jig 30. In other words, the second terminal T2 includes the terminal fixing projection 18 provided on the tip of the second terminal T2. The terminal fixing projection 18 is a claw-shaped projection formed by partially grinding down the terminal spring portion 14 or bending the tip of the terminal spring portion 14. When the chuck jig 30 pushes down the motor-side busbar terminal 51, the motor-side busbar terminal 51 comes into contact with the terminal spring portion 14 and pushes down the terminal fixing projection 18. When the motor-side busbar terminal 51 pushes down the terminal fixing projection 18 further, the angle of the terminal spring portion 14 changes to a position where it is visible from the tip of the motor-side busbar terminal 51. At this time, as shown in Figure 22(b), the terminal fixing projection 18 extends beyond the tip of the motor-side busbar terminal 51, causing the tip of the motor-side busbar terminal 51 to catch on the terminal fixing projection 18. This allows the motor-side busbar terminal 51 and the terminal spring portion 14 to remain in close contact even after the pressing by the chuck jig 30 is completed. In other words, the tip of the first terminal T1 is fixed to the terminal fixing projection 18 while caught on it. By irradiating the terminal with a laser in this state and welding it, the weldable area can be increased, thus making the quality of the welding more stable. In addition, even if the plate material of the terminal spring portion 14 melts off during welding, it is possible to prevent it from penetrating both the plate material and the module AC terminal 12 below it.

[0052] Next, the effects and advantages of Embodiment 6 will be described. According to the terminal structure TS of Embodiment 6, the tip of the first terminal T1 is fixed to the terminal fixing projection 18 while being hooked onto the terminal fixing projection 18. Therefore, the tip of the first terminal T1 can be hooked onto the terminal fixing projection 18 and fixed. Consequently, the terminal can maintain a tight seal even when the pressure from the chuck jig 30 is removed. Furthermore, by improving the tight seal of the terminals, welding can be stabilized. In addition, when the tip of the first terminal T1 is hooked onto the terminal fixing projection 18, it is easy to confirm that the terminals are tightly sealed.

[0053] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended.

[0054] The various forms of this disclosure are summarized below as an appendix. (Note 1) A first terminal having a welding surface, The system comprises a second terminal welded to the first terminal on the opposite side of the welding surface, The terminal structure is such that the second terminal is welded in a state where it is folded into two or more layers.

[0055] (Note 2) The terminal structure described in Appendix 1, wherein when the first terminal is viewed from the welding surface, the tip of the second terminal protrudes from the first terminal.

[0056] (Note 3) The terminal structure according to Appendix 1 or 2, wherein the thickness of the first terminal is greater than the thickness of the second terminal.

[0057] (Note 4) The second terminal includes a terminal position detection unit provided on the side surface of the second terminal. The terminal position detection unit is a terminal structure according to any one of the appendices 1 to 3, which extends from the first terminal when the first terminal is viewed from the welding surface.

[0058] (Note 5) Either the first terminal or the second terminal includes either a terminal position adjustment recess or a terminal position adjustment protrusion. Either the first terminal or the second terminal includes the other, and either the terminal position adjustment recess or the terminal position adjustment protrusion includes the other. The terminal structure according to any one of the appendices 1 to 4, wherein the terminal position adjustment recess and the terminal position adjustment protrusion are interlocked with each other.

[0059] (Note 6) The first terminal includes a terminal receiving portion having a slope that reduces the thickness of the first terminal toward the tip of the first terminal. The terminal receiving portion is welded to the second terminal, as described in any one of the appendices 1 to 5.

[0060] (Note 7) The second terminal includes a terminal bending portion, The terminal bending portion is curved so as to bulge outwards, as described in any one of the appendices 1 to 6.

[0061] (Note 8) The second terminal includes a terminal fixing projection provided at the tip of the second terminal, The terminal structure described in Appendix 2, wherein the tip of the first terminal is fixed to the terminal fixing projection while being hooked onto the terminal fixing projection.

[0062] (Note 9) The terminal structure described in any one of the appendices 1 to 8, Equipped with multiple electronic components, The aforementioned plurality of electronic components are connected by the terminal structure, in a power conversion device.

[0063] (Note 10) A first terminal having a welding surface is positioned on the opposite side of the welding surface and is pressed against a second terminal that is folded in two or more layers, thereby promoting the bending of the second terminal until the tip of the second terminal protrudes from the first terminal when viewed from the welding surface. A method for manufacturing a terminal structure, comprising the step of welding the first terminal and the second terminal from the welding surface of the first terminal so that the tip of the second terminal protrudes from the first terminal when viewed from the welding surface. [Explanation of symbols]

[0064] 1 Power converter, 2 Housing, 3 Heat dissipation section, 5 Battery, 6 Motor, 7 Sensor, 8 Control board, 10 Power module, 11 Module control terminal, 12 Module AC terminal, 13 Module PN terminal, 14 Terminal spring section, 15 Terminal position detection section, 16 Terminal bending section, 22 Terminal receiving section, 18 Terminal fixing projection, 20 Terminal position adjustment protrusion, 21 Terminal position adjustment recess, 30 Chuck jig, 31 Laser output device, 32 Terminal condition inspection device, 40 Welding laser, 41 Welded section, 50 Motor-side busbar unit, 51 Motor-side busbar terminal, 60 Capacitor, 61 Electronic component terminal, S1 Pressing process, S2 Welding process, T1 First terminal, T2 Second terminal, TS Terminal structure, WS Welding surface.

Claims

1. A first terminal having a welding surface, The system comprises a second terminal welded to the first terminal on the opposite side of the welding surface, The terminal structure is such that the second terminal is welded in a state where it is folded into two or more layers.

2. The terminal structure according to claim 1, wherein when the first terminal is viewed from the welding surface, the tip of the second terminal protrudes from the first terminal.

3. The terminal structure according to claim 1, wherein the thickness of the first terminal is greater than the thickness of the second terminal.

4. The second terminal includes a terminal position detection unit provided on the upper side surface of the second terminal. The terminal position detection unit is located extending from the first terminal when viewed from the welding surface, according to the terminal structure of claim 1.

5. Either the first terminal or the second terminal includes either a recess for adjusting the terminal position or a protrusion for adjusting the terminal position. Either the first terminal or the second terminal includes the other, and either the terminal position adjustment recess or the terminal position adjustment protrusion includes the other. The terminal structure according to claim 1, wherein the recess for adjusting the terminal position and the protrusion for adjusting the terminal position are interlocked with each other.

6. The first terminal includes a terminal receiving portion having a slope that reduces the thickness of the first terminal toward the tip of the first terminal. The terminal structure according to claim 1, wherein the terminal receiving portion is in contact with the second terminal.

7. The second terminal includes a terminal bending portion, The terminal structure according to claim 1, wherein the bent portion of the terminal is curved so as to bulge outwards.

8. The second terminal includes a terminal fixing projection provided at the tip of the second terminal, The terminal structure according to claim 2, wherein the tip of the first terminal is fixed to the terminal fixing projection while being hooked onto the terminal fixing projection.

9. The terminal structure according to any one of claims 1 to 8, Equipped with multiple electronic components, The aforementioned plurality of electronic components are connected by the terminal structure, in a power conversion device.

10. A first terminal having a welding surface is positioned on the opposite side of the welding surface and is pressed against a second terminal that is folded in two or more layers, thereby promoting the bending of the second terminal until the tip of the second terminal protrudes from the first terminal when viewed from the welding surface. A method for manufacturing a terminal structure, comprising the step of welding the first terminal and the second terminal from the welding surface of the first terminal in such a state that the tip of the second terminal protrudes from the first terminal when viewed from the welding surface.

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