Switch cell with connection device

Abstract

The present invention relates to a switching cell (1) comprising a power module (2) and an intermediate circuit capacitor (4), wherein the power module (2) has a terminal (14) with a first polarity and a terminal (16) with a second polarity, wherein the intermediate circuit capacitor (4) comprises a connecting terminal (18) with the second polarity which is welded to the terminal (16) with the second polarity, wherein the intermediate circuit capacitor (4) comprises a connection device (22) comprising a leg (30) which includes a connecting terminal (24, 24, 24B) with the first polarity in contact with the terminal (14) with the first polarity, wherein the connecting terminal (18) with the second polarity is layered between the terminal (16) with the second polarity and the leg (30), and wherein the connection device (22) has a hole (32) in its leg (30) includes.

Description

[0001] The present invention relates to the fields of electronics and electrical engineering, and in particular to the field of switching cells.

[0002] Switching cells are power electronic devices that can generate alternating current from direct current. These cells can be integrated into motor vehicles, particularly hybrid or electric vehicles, to convert direct current supplied by batteries into alternating current to power the electric motor.

[0003] Switching cells typically comprise a power module and a DC link capacitor, which are interconnected within the switching cell. The power module contains various power components, while the DC link capacitor acts as a buffer to compensate for fluctuations.

[0004] In some switching cells, the power module and the DC link capacitor are stacked, with the power module, for example, being placed on top of the DC link capacitor when the switching cell is integrated into the vehicle. Newer versions of switching cells have been developed in which the power module and the DC link capacitor are positioned side by side, for example, parallel to a vehicle floor. In these embodiments, due to the different positioning of the power module relative to the DC link capacitor, new methods for connecting these two components of the switching cell must be found.

[0005] Often, the terminals or connection points of the power module are spaced apart to maintain clearance and creepage distance, as well as to accommodate manufacturing processes such as screw connections. Due to this spacing between the terminals, the magnetic field is not properly compensated, leading to undesirable levels of stray inductance.

[0006] To compensate for magnetic fields while limiting leakage inductance, the terminals of the DC link capacitor can have a specific shape that covers the gap between the terminals of the power module. This special terminal shape allows one terminal to overlap the other. For example, a terminal with a first polarity of the DC link capacitor is covered by a terminal with a second polarity. The terminal with the first polarity of the DC link capacitor is connected to at least one terminal with the first polarity of the power module, while the terminal with the second polarity of the DC link capacitor is connected to at least one terminal with the second polarity of the power module. During the manufacturing of the switching cell, the power module and the DC link capacitor must be welded together.For such a weld to be successful, there should be no air gap, or at least a minimal air gap, between the power module and the DC link capacitor. Otherwise, the laser beam of the welding tool will be interrupted, and a connection cannot be established. One way to limit air gaps is to press the two components to be welded together. While such pressing to ensure an air-gap-free weld is easily achieved when connecting the terminal with the second polarity of the DC link capacitor to the corresponding terminal of the power module, covering the terminal with the first polarity of the DC link capacitor with its terminal with the second polarity can hinder pressing between the terminal with the first polarity and the corresponding terminal of the power module.

[0007] The present invention fits into this context by providing a switching cell in which a terminal with a given polarity of the power module and a terminal with the same polarity of the DC link capacitor can be easily welded together, even if the terminal of the DC link capacitor is covered by another of its terminals.

[0008] In this context, the present invention relates to a switching cell for a motor vehicle, comprising a power module and an intermediate circuit capacitor, wherein the power module has at least one terminal with a first polarity and at least one terminal with a second polarity, wherein the intermediate circuit capacitor comprises a connection device with at least one terminal with the second polarity, which is welded to the terminal with the second polarity of the power module, wherein the intermediate circuit capacitor comprises a connection device comprising at least one leg, which includes at least one terminal with the first polarity in contact with the terminal with the first polarity of the power module, wherein the leg of the connection device covers the terminal with the second polarity and the terminal with the second polarity.wherein the connecting device includes at least one hole in its leg which faces the connecting flag with the second polarity.

[0009] The switching cell according to the invention is intended to be implemented in a vehicle, for example in a hybrid or electric vehicle, to drive its electric motor. The switching cell comprises a power module which is connected to a DC link capacitor via a connecting device and a terminal device. The switching cell is a flat switching cell and not a stacked switching cell; the DC link capacitor and the power module are located next to each other, whereas in a stacked switching cell, the power module is stacked above the DC link capacitor during installation of the switching cell in the vehicle.

[0010] The power module has terminals with different polarities, corresponding to at least one negative and one positive terminal. The terminal with the first polarity can be a negative terminal and the terminal with the second polarity a positive terminal, or vice versa. The power module can comprise one or more phase modules, each comprising a half-bridge and corresponding to one AC phase. If multiple phase modules are present, each has at least one terminal with the first polarity and one terminal with the second polarity.

[0011] The connecting device and the terminal extend from the intermediate circuit capacitor to the power module. The terminal has a connecting tab that is in contact with the terminal of the first polarity, here the negative terminal, thus corresponding to a first-polarity connecting tab. The connecting device has a connecting tab that is in contact with the terminal of the second polarity, here the positive terminal of the power module, thus corresponding to a second-polarity connecting tab. More precisely, the first-polarity connecting tab of the connecting device is welded to the negative terminal of the power module. Likewise, the second-polarity connecting tab of the connecting device is welded to the positive terminal of the power module.In the switching cell, the connection device of the DC link capacitor can be superimposed. More precisely, the connection device is superimposed on the secondary polarity connection lug, which in turn is superimposed on the secondary polarity connection lug of the power module. The secondary polarity connection lug is layered between the connection device and the secondary polarity connection lug. In other words, the secondary polarity connection lug, and therefore also the connection device, has a first surface facing the secondary polarity connection lug and a second surface facing the connection device. More precisely, the first surface of the connection device faces one leg of the connection device. This leg of the connection device connects its first polarity connection lug to a body of the connection device.

[0012] To weld the secondary polarity terminal of the power module to the secondary polarity connection terminal of the DC link capacitor, and especially to their secondary surfaces, the air gap between these two terminals must be minimal. It is therefore advantageous to press the secondary polarity terminal and the secondary polarity connection terminal together. To enable such pressing while avoiding damage to the terminal assembly, the leg of the terminal assembly has a hole. This hole is specifically designed to provide a passage for a support tool of a welding device for the switching cell, with this support tool being used to press the secondary polarity connection terminal against the secondary polarity terminal.

[0013] According to an optional feature of the invention, the hole in the leg of the connecting device has a shape complementary to a shape of a support tool of a welding device of the switching cell.

[0014] This complementarity of shapes between the hole and the support tool allows the support tool to easily pass through the hole. The hole is, for example, circular.

[0015] According to an optional feature of the invention, the hole in the leg of the connection device is centered within the leg of the connection device according to an alignment direction of the connection lugs of the power module.

[0016] Such centering of the hole within the leg helps to ensure that the support tool is correctly positioned with respect to the connecting flag with the second polarity, which is itself centered with respect to the leg.

[0017] According to an optional feature of the invention, the connection lugs of the power module are located in the same connection plane and are separated by a space, wherein the connection device comprises a cover part covering the space between the connection lugs, the cover part being offset from the connection lug with the first polarity perpendicular to the connection plane.

[0018] In other words, the terminals are not contiguous. The space between the terminals lies in the same plane in which they extend. The cover of the terminal device extends from one terminal to the other, that is, from the terminal with the first polarity to the terminal with the second polarity. The cover thus covers the space between these two terminals. The resulting increased overlap between the terminals provides a current path, thereby compensating for the magnetic fields and resolving the leakage inductance problems.

[0019] The connection device is not flat in that there is an offset between the connecting tab with the first polarity and the cover part. As a result, the connecting tab with the first polarity and the cover part extend mainly in two substantially parallel planes.

[0020] According to an optional feature of the invention, the power module comprises at least one set of two terminals with the first polarity and one terminal with the second polarity, the terminal with the second polarity being arranged between the two terminals with the first polarity. Consequently, in the connection plane, the positive terminal is surrounded by the two negative terminals. In such embodiments, the terminal with the second polarity of the DC link capacitor thus extends between the two terminals with the first polarity, i.e., the two negative terminals. Each of the terminals with the first polarity is in contact with a terminal with the first polarity of the connection device, while the terminal with the second polarity is covered by the cover part between them.

[0021] According to an optional feature of the invention, the cover part of the connection device is located at a non-zero distance from the connecting tab with the first polarity of the intermediate circuit capacitor.

[0022] This means that the cover of the connector and the connecting lug with the second polarity do not touch to prevent short circuits. The cover of the connector extends over a free end of the connecting lug with the second polarity, while the leg of the connector extends over a body of the connecting lug with the second polarity.

[0023] According to an optional feature of the invention, the switching cell comprises at least one insulating means, wherein the insulating means covers at least a part of the cover part of the connecting device.

[0024] The insulating material is used to prevent gaps and creepage problems within the switchgear. The insulating material is an insulating layer, such as insulating paper, a coating, or the like. If the insulating material is insulating paper, it can be bent over an edge of the connector. To ensure it stays in position on the connector, the insulating material can be bonded to it. A coating is an alternative to insulating paper, allowing for a thinner insulating material. Multiple insulating materials are present if there are multiple phase modules, each connected to one of the legs of the connector.

[0025] According to an optional feature of the invention, the cover part of the connection device has a top, a bottom and an edge connecting the top and the bottom, wherein the edge faces the power module, wherein the insulating means has a first part that at least partially covers the bottom of the cover part, a second part that at least partially covers the top of the cover part, and a third part that at least partially covers the edge of the cover part.

[0026] Thus, the first part of the insulating material is positioned between the connection device and the terminal lug with the second polarity to prevent short circuits between these two components.

[0027] According to an optional feature of the invention, the first part of the insulating material covering the underside of the cover part of the connection device extends along the leg of the connection device between the connection device and the connecting lug with the second polarity, the first part covering the hole in the leg of the connection device.

[0028] The insulating material has no hole because insulation is required between the connection device and the connecting lug with the second polarity. Furthermore, a hole in the insulating material is unnecessary because it does not impede the insertion of the support tool through the hole in the leg. The insulating material is thin and / or flexible enough to allow sufficient insertion.

[0029] According to an optional feature of the invention, the second part of the insulating material covering the top of the cover part of the connection device extends to a point in a circumferential boundary of the hole in the leg of the connection device, this point being closest to the edge of the cover part of the connection device.

[0030] In other words, the insulating material does not cover the hole in the leg on both sides of the connection device, as this would hinder the pushing of the support tool through the hole in the leg and would lead to deformation or possible damage to the insulating material.

[0031] According to an optional feature of the invention, the power module comprises several phase modules, each phase module having at least one terminal with the first polarity and one terminal with the second polarity, the connection device having a common body and several legs extending from the common body, each leg being in contact with the terminal with the first polarity of a given phase module, each leg having a hole.

[0032] The phase modules are aligned along one side of the DC link capacitor, towards which the terminals extend. For example, three phase modules, each corresponding to an AC phase, are aligned facing the DC link capacitor to provide a three-phase current.

[0033] The connection device has a common body extending along the multiple phase modules, with one leg extending from this common body to each phase module; there is a first leg for the first phase module, a second leg for the second phase module, and a third leg for the third phase module.

[0034] According to an optional feature of the invention, a free end of the connecting tab with the second polarity of the intermediate circuit capacitor is inclined towards the connecting tab with the second polarity of the power module.

[0035] In other words, the connecting tab with the second polarity is not straight. It has a flat central section extending parallel to the leg of the connecting device and a beveled free end inclined in the opposite direction to the connecting device. The inclination of the free end of the connecting tab with the second polarity is thus opposite to the surface of the connecting tab with the second polarity against which the support tool presses. This ensures that the connecting tab with the second polarity comes into contact with the connecting tab with the second polarity.

[0036] According to an optional feature of the invention, the connecting tab with the first polarity of the connecting device has an extension with a positioning hole.

[0037] The positioning hole helps to position the connection device relative to the power module.

[0038] The invention also relates to a method for manufacturing a switching cell, as described above, comprising a positioning step in which the connection device is positioned so that it covers the connecting device, a first welding step in which the connecting tab with the first polarity and the connection tab with the first polarity are welded together, a second welding step in which the connecting tab with the second polarity and the connection tab with the second polarity are welded together, wherein the second welding step comprises a partial step of positioning a support tool of a welding device through the hole of the connection device in order to press the connecting tab with the second polarity against the connection tab with the second polarity.

[0039] During the positioning step, the support tool of the welding device is positioned more precisely against the insulating medium of the connection device and presses through the insulating medium onto the connecting tab with the second polarity.

[0040] Further features, details and advantages of the invention will become clearer on the one hand by reading the following description and on the other hand by several examples of implementation, which are given as guidelines and without limitation with reference to the attached schematic drawings. [ Fig. Figure 1] is a schematic representation of a switching cell according to the invention, wherein the switching cell comprises a power module, a DC link capacitor and a connection device, wherein the DC link capacitor and the power module are arranged side by side; [ Fig. 2] is an isolated view of the connection device of the switching cell of Fig. 1; [ Fig. Figure 3] is a top view of part of the intermediate circuit capacitor and the connection device; [ Fig. [4] is a cross-sectional view of a connecting flange of the power module of Fig. 1, which is arranged below the connection device and an insulating medium; [ Fig. 5] is a schematic representation of the switching cell of Fig. 1 during its manufacture, wherein the switching cell comprises a welding device with a support tool.

[0041] The features, variants, and different ways of implementing the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention are conceivable that include only a selection of the features described below from the other described features, if this selection of features is sufficient to achieve a technical advantage and / or to differentiate the invention from the prior art.

[0042] In the drawings, identical numbers refer to identical elements.

[0043] In the following description, the terms "longitudinal," "transverse," and "vertical" refer to the orientation of the switching cell according to the invention. A longitudinal direction corresponds to a direction in which the power module, the intermediate circuit capacitor, and a space between their main bodies are aligned, wherein the power module and the intermediate circuit capacitor are positioned side by side, and this longitudinal direction runs parallel to a longitudinal axis L of a coordinate system L, V, T shown in the figures. A transverse direction corresponds to a direction in which the terminals of the power module are aligned, and this transverse direction runs parallel to a transverse axis T of the coordinate system L, V, T and perpendicular to the longitudinal axis L. Finally, a vertical direction corresponds to a vertical axis V of the coordinate system L, V, T, wherein the vertical axis V runs perpendicular to the longitudinal axis L and the transverse axis T.

[0044] The Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Figure 5 schematically depicts a switching cell 1 according to the invention. The switching cell 1 is configured for installation in a motor vehicle, such as an electric or hybrid vehicle, and serves to generate an alternating current suitable for driving the vehicle's motor. For this purpose, the switching cell 1 comprises a power module 2, which houses various power components and a DC link capacitor 4 for energy storage.

[0045] As shown in the figures, in the present embodiment the power module 2 comprises three phase modules, with a first phase module 2A, a second phase module 2B, and a third phase module 2C. Each phase module 2A, 2B, 2C is a half-bridge phase module. Unless otherwise specified, everything described below with respect to any one of these phase modules 2A, 2B, 2C can be applied to any or all of the phase modules 2A, 2B, 2C.

[0046] In switching cell 1, the power module 2 and the intermediate circuit capacitor 4 are arranged side by side, as shown in Fig. Figure 1 shows that the power module 2 has a main body 6 and the DC link capacitor 4 has a main body 8, with the main body 6 of the power module 2 and the main body 8 of the DC link capacitor 4 lying next to each other. If three phase modules 2A, 2B, 2C are present in the power module 2, they are oriented such that a front surface 10 of each of their main bodies 6 faces the DC link capacitor 4, with the front surfaces 10 of the phase modules 2A, 2B, 2C lying in the same plane.

[0047] The main body 6 of the power module 2 and the main body 8 of the DC link capacitor 4 face each other but are located at a non-zero distance from one another; they are separated by a corridor 12, which is a space between the main body 6 of the power module 2 and the main body 8 of the DC link capacitor 4. This corridor 12 extends mainly along a transverse direction T, while the power module 2, the corridor 12, and the DC link capacitor 4 are aligned along a longitudinal direction L, which corresponds to a main direction of the switching cell 1. The corridor 12 is the part of the switching cell 1 in which the power module 2 and the DC link capacitor 4 are connected, as will now be described.

[0048] As especially in Fig. As can be seen in Figure 1, the power module 2 has connection lugs, including at least one connection lug with a first polarity 14 and at least one connection lug 16 with a second polarity. The first-polarity connection lug 14 is a negative terminal of the power module 2, while the second-polarity connection lug 16 is a positive terminal. The connection lugs 14 and 16 are rectangular in shape. As shown here, they extend in corridor 12 from the front surface 10 of the main body 6 of the power module 2 substantially perpendicular to this front surface 10 in the direction of the intermediate circuit capacitor 4. They extend mainly in a longitudinal-transverse plane that corresponds to a connection plane of the switching cell 1.

[0049] Here, the power module 2 comprises two terminals 14 with the first polarity and a single terminal 16 with the second polarity, wherein this terminal 16 with the second polarity is positioned in the middle of the two terminals 14 with the first polarity in the connection plane. Consequently, a single positive terminal is arranged between two negative terminals. If three phase modules 2A, 2B, 2C are present, as is the case in the present embodiment, each of these phase modules 2A, 2B, 2C comprises a terminal 16 with the second polarity, which is positioned in the middle of two terminals 14 with the first polarity within the connection plane.

[0050] The terminals 14 and 16 are separated from each other by a space in the connection plane in such a way that they do not come into contact with each other, which would otherwise lead to short circuits. Thus, there is a first space between one of the terminals 14 with the first polarity and the terminal 16 with the second polarity, and a second space between this terminal 16 with the second polarity and the other terminal 14 with the first polarity.

[0051] The DC link capacitor 4 comprises a connection device 17, which extends mainly between the power module 2 and the main body 8 of the DC link capacitor 4, at least partially within the corridor 12. The connection device 17 comprises at least one connecting lug 18 with the second polarity. Preferably, the connection device 17 has as many connecting lugs 18 with the second polarity as there are phase modules 2A, 2B, 2C; in the present embodiment, the connection device 17 comprises three connecting lugs 18 with the second polarity. The connection device 17 corresponds to a busbar with the second polarity of the DC link capacitor 4.

[0052] Each connecting lug 18 with the second polarity extends from a front side 20 of the intermediate circuit capacitor 4, which faces the front side 10 of the power module and participates in the delimitation of the corridor 12. The connecting lug 18 with the second polarity extends from this front side 20 substantially perpendicular to it in a plane that runs parallel to the connecting plane of the connecting lugs 14, 16.

[0053] The connecting tab 18 with the second polarity is in contact with the power module 2; in particular, the connecting tab 18 with the second polarity is in contact with the terminal 16 with the second polarity of the power module 2. In other words, the connecting tab 18 with the second polarity and the terminal 16 with the second polarity extend such that they at least partially overlap. If two terminal 14s with the first polarity are present, the connecting tab 18 with the second polarity extends between them along the transverse direction D at an equal distance from the two terminal 14s with the first polarity. The connecting tab 18 with the second polarity is welded to the terminal 16 with the second polarity of the power module 2.

[0054] The switching cell 1 has a connection device 22 which extends mainly between the power module 2 and the intermediate circuit capacitor 4, at least partially within the corridor 12. Such a connection device 22 is particularly evident in Fig. 2. The connection device 22 is a metal part of the switching cell 1; as such, it can be made of copper or aluminum. The connection device 22 corresponds to a busbar with the first polarity of the intermediate circuit capacitor 4. It is therefore understood that the connection device 22 and the connecting device 17, although they have different polarities, have the same function, namely the electrical connection of the intermediate circuit capacitor 4 to the power module 2.

[0055] In Fig. Figure 1 shows the power module 2, the intermediate circuit capacitor 4 with its connecting device 17 and the connection device 22 separated, with dashed lines indicating their relative positions.

[0056] The connecting device 22 is now referred to Fig. 2 described in more detail. The connection device 22, as shown here, is configured for connection to the connection lugs 14 with the first polarity of the three phase modules 2A, 2B, 2C, i.e. with six different connection lugs 14 with the first polarity, since each phase module 2A, 2B, 2C has two connection lugs 14 with the first polarity.

[0057] The connection device 22 has a common body 28 that extends mainly along the transverse direction T. This common body 28 protrudes from the intermediate circuit capacitor 4, as shown in particular in Fig. 4 can be seen. More precisely, the common body 28 of the connection device 22 protrudes along a vertical direction V of the switching cell 1 from the intermediate circuit capacitor 4 and is bent along the longitudinal direction L so that it extends to the power module, here the three phase modules 2A, 2B, 2C.

[0058] The connection device 22 comprises at least one connecting lug 24 with the first polarity and at least one cover part 26, which are connected to the common body 28 by a leg 30 of the connection device 22. The leg 30 extends along the longitudinal direction L to the power module 2. More precisely, the leg 30 connects the common body 28 to the cover part 26, which in turn connects the leg 30 to the connecting lug 24 with the first polarity. There are as many legs 30 as there are phase modules 2A, 2B, 2C; the connection device 22 is shown here with three legs 30A, 30B, 30C, corresponding to the first, second, and third phase modules 2A, 2B, 2C, but in embodiments with a power module 2 comprising a single phase module, there could be only a single leg 30. If there are multiple legs 30, they are spaced apart from each other by gaps within the connecting device 22.The second leg 30B is located between the first leg 30A and the third leg 30C and is essentially equidistant from them.

[0059] The leg 30 of the connecting device 22 extends over the connecting lug 18 with the second polarity of the intermediate circuit capacitor 4. The leg 30 has a width, measured along the transverse axis T, that is greater than the width of the connecting lug 18 with the second polarity, measured in the same direction. As shown in particular in the Fig. 1, Fig. 2 to Fig. As can be seen in Figure 3, the leg 30 of the connecting device 22 includes a hole 32. Optionally, each leg 30 includes a hole 32. This hole 32, which is a through hole, is circular in shape. The hole 32 is centered within the leg 30 of the connecting device 32 along the transverse direction T, meaning that the hole 32 is centered within the width of the leg 30. One diameter of the hole 32 corresponds to the width of the connecting tab 18 with the second polarity, this width being measured along the transverse direction T.

[0060] The connection device 22 can include a positioning hole 33, which serves to position it relative to other components of the switching cell 1, which may have a suitable positioning pin. As can be seen in particular from the Fig. 2 and Fig. As can be seen in Figure 3, the positioning hole 33 is formed here in an extension of the connecting flag 24 with the first polarity of the connecting device 22.

[0061] The connecting tab 24 with the first polarity of the connecting device 22 is configured to contact the connecting tab 14 with the first polarity, while its cover part 26 covers at least the space between the connecting tab 14 with the first polarity and the connecting tab 16 with the second polarity, which is located next to it.

[0062] The cover part 26 and the leg 30 from which it extends are configured to extend over the connecting tab 18 with the second polarity of the intermediate circuit capacitor 4.

[0063] The connecting lug 24 with the first polarity, carried by the first leg 30A, is in contact with the terminal lug 14 with the first polarity of the first phase module 2A; the connecting lug 24 with the first polarity, carried by the second leg 30B, is in contact with the terminal lug 14 with the first polarity of the second power module 2B; and the connecting lug 24 with the first polarity, carried by the third leg 30C, is in contact with the terminal lug 14 with the first polarity of the third power module 2C. If applicable, the two connecting lugs 24 with the first polarity extending from each leg 30A, 30B, 30C are in contact with the two terminal lugs 14 with the first polarity of the corresponding phase module 2.

[0064] Likewise, the cover part 26 of the first leg 30A covers the space between the connection lugs 14, 16 of the first phase module 2A, the cover part 26 of the second leg 30B covers the space between the connection lugs 14, 16 of the second phase module 2B, and the cover part 26 of the third leg 30C covers the space between the connection lugs 14, 16 of the third phase module 2C.

[0065] The connection device 22 is not flat; in other words, it does not extend in a single plane. Consequently, there is an offset within the connection device 22, which is particularly noticeable in Fig. 2 is visible.

[0066] The offset lies more precisely between the connecting lug 24 with the first polarity and the cover part 26. The connecting lug 24 with the first polarity and the cover part 26 therefore extend largely in two different planes, which are essentially parallel to each other and parallel to the connecting plane of the connecting lugs 14, 16. The connecting lug 24 with the first polarity and the cover part 26 are connected to each other by a curved section 34, which forms a curvature within the connecting device 22. In other words, the cover part 26 extends mainly in the same plane as the leg 30 to which it is attached, while the connecting plane 24 is located in a different plane due to the curved section 34. This other plane is a lower plane when the switching cell 1 is installed in the motor vehicle.

[0067] If, for a given phase module 2A, 2B, 2C, two terminal lugs 14 of the first polarity surround a single terminal lug 16 of the second polarity, the corresponding leg 30 of the connection device 22 comprises a single cover part 26 and two connecting lugs 24 of the first polarity. The two connecting lugs 24 of the first polarity, namely a first connecting lug 24A of the first polarity and a second connecting lug 24B of the first polarity, extend transversely from opposite sides of the cover part 24. Both the first connecting lug 24A of the first polarity and the second connecting lug 24B of the first polarity are connected to the cover part 24 via a curved section 34. The two connecting lugs 24A, 24B of the first polarity extend in the same plane.

[0068] As already mentioned, the connecting lug 24 with the first polarity of the connection device 22 is in contact with the connecting lug 14 with the first polarity; optionally, each of the two connecting lugs 24A, 24B with the first polarity is in contact with one of the two connecting lugs 14 with the first polarity of a given phase module 2. The connecting lug 24 with the first polarity of the connection device 22 is welded to the connecting lug 14 with the first polarity of the phase module 2.

[0069] The cover part 26 covers at least the space between two terminal lugs 14, 16. If the phase module 2A, 2B, 2C comprises two terminal lugs 14 of the first polarity surrounding a terminal lug 16 of the second polarity, the cover part covers both the first space between one of the terminal lugs 14 of the first polarity and the terminal lug 16 of the second polarity, and the second space between this terminal lug 16 of the second polarity and the other terminal lug 14 of the first polarity. Due to the offset caused by the curved section 34, the cover part 26 is not in contact with the terminal lug 16 of the second polarity; it extends over it at a non-zero distance.Furthermore, the cover part 26 is located at a non-zero distance from the connecting tab 18 with the second polarity of the intermediate circuit capacitor 4 and the terminal tab 16 with the second polarity. More precisely, the connecting tab 18 with the second polarity of the intermediate circuit capacitor 4 is positioned between the terminal device 22 and the terminal tab 16 with the second polarity.

[0070] As in Fig. As shown in Figure 4, the connection device 22 has a top surface 36 and a bottom surface 38, the bottom surface 38 being the side facing the connection lugs 14, 16 and the connection lug 18 with the second polarity, while the top surface 36 is opposite it. The top surface 36 and the bottom surface 38 are connected by an edge 40, which corresponds to a side of the connection device 22 facing the front surface 10 of the power module 2.

[0071] In the illustrated embodiment, where the connecting tab 18 with the second polarity of the intermediate circuit capacitor 4 is layered between the terminal device 22 and the connecting tab 16 with the second polarity, the connecting tab 18 with the second polarity, and thus the connecting device 17, have a first surface 42 facing the underside 38 of the terminal device 22, and a second surface 44 opposite the first surface 42, facing the connecting tab 16 with the second polarity. While the second surface 44 of the connecting tab 18 with the second polarity is in contact with the connecting tab 16 with the second polarity when they are welded, the first surface 42 of the connecting tab 18 with the second polarity is located at a non-zero distance from the underside 38 of the terminal device 22.

[0072] In the resulting space between the connecting lug 18 with the second polarity and the terminal device 22, the switching cell 1 includes an insulating medium 46. More precisely, this insulating medium 46 covers at least a part of the terminal device 22, as shown in the Fig. 2, Fig. 3 and Fig. Figure 4 shows. According to the embodiments, the insulating medium 46 can be insulating paper or a coating made of an insulating material.

[0073] The switching cell 1 comprises an insulating element 46 for each leg 30 of the connection device 22; thus, three insulating elements 46 are provided, each covering at least a part of one of the legs 30A, 30B, 30C.

[0074] At least a portion of the insulating material 46 extends along a lower surface of the leg 30 and covers it over its entire longitudinal extent. As such, the insulating material extends from the common body 28 to a tip of the leg 30 that encompasses the cover portion 26. As shown in Fig. As shown in Figure 2, the insulating medium 46 can extend further than the leg 30 in the transverse direction T and thus goes further than the edges of the leg 30.

[0075] The insulating material 46 is more precisely formed from a first part 48, a second part 50, and a third part 52. The first part 48 of the insulating material 46 covers at least partially the underside 38 of the connection device 22, its second part 50 covers at least partially the top side 36 of the connection device 22, and its third part 52 covers at least partially the edge 40 of the connection device 22.

[0076] As in the Fig. 2 and Fig. As can be seen in Figure 3, the insulating material 46 covers at least part of the cover part 26 of the connection device 22. In the transverse direction, the insulating material 46 extends from the curved section 34 between the first connection section 24A and the cover part 26 on the one hand, to the curved section 34 between the cover part 26 and the second connection section 24B on the other hand, although the insulating material does not cover the curved sections 34. It is understood that the insulating material 46 does not cover the connection sections 24A and 24B.

[0077] Due to its first part 48 covering the underside 38 of the connection device 22, its second part 50 covering the top 36, and its third part 52 covering the edge 40, the insulating medium 46 is U-shaped. This is particularly evident in Fig. 4 to see. In this Fig. Figure 4 also shows that a longitudinal dimension of the first part 48 of the insulating material 46 differs from a longitudinal dimension of its second part 50. The first part 48 of the insulating material 46 extends from the intermediate circuit capacitor 4 to the edge 40 of the terminal 22. Thus, the first part 48 of the insulating material 46 extends along the entire longitudinal dimension of the underside 38 of the terminal 22. Therefore, the first part 48 of the insulating material 46 covers the hole 32 in the leg 30 on the underside 38 of the terminal 22. In contrast, the second part 50 of the insulating material 46 does not extend over the entire longitudinal dimension of the top side 36 of the terminal 22. The second part 50 of the insulating material 46 is shorter than its first part 48.The second part 50 of the insulating medium 46 extends to the hole 32 in the leg 30 without covering it; in other words, the insulating medium 46 terminates on the top 36 of the connection device 22 at a circumferential edge of the hole 32.

[0078] It should be noted that while the second-polarity connecting tab 18 has a flat section extending along the leg 30 of the terminal 22, its free end 54, which is connected to the second-polarity connecting tab 16 of the power module 2, is inclined. In other words, the free end 54 of the second-polarity connecting tab 18 is located at a greater distance from the cover part 26 of the terminal 22 than the flat section of the connecting tab 18 is from the leg 30 of the terminal 22. For example, the angle between the plane in which the flat section of the second-polarity connecting tab 18 mainly extends and the plane in which the free end 54 of the second-polarity connecting tab 18 mainly extends is 2° or 3°.

[0079] Now, a method for manufacturing a switching cell 1, as described above, is presented with reference to Fig. 5 is described in detail. The method for manufacturing the switching cell 1 initially comprises manufacturing steps during which the power module 2 and the DC link capacitor 4 are produced. If necessary, several phase modules 2A, 2B, 2C are produced to form the power module 2. During the manufacture of the DC link capacitor 4, its main body 8 is joined with both the connecting device 17 and the terminal device 22. During a positioning sub-step of the manufacturing step of the DC link capacitor 4, the terminal device 22 is positioned so that it covers the connecting tab 18 with the second polarity of the DC link capacitor 4.

[0080] Then the power module 2 and the intermediate circuit capacitor 4 must be joined together. For this purpose, the power module 2 and the intermediate circuit capacitor 4 are placed next to each other. It should be noted that, as in Fig. As can be seen in Figure 5, the power module 2 and the intermediate circuit capacitor 4 can be positioned upside down in a welding fixture 56 used to perform the first welding step. More precisely, the components of the switching cell 1 are positioned in the welding fixture 56 such that the connecting lug 24 with the first polarity of the terminal device 22, or, if applicable, all of its connecting lugs 24 with the first polarity, rest on support tools 58 of the welding fixture 56. Then, clamps 60 of the welding fixture 56 are used to press down on the connecting lugs 14 with the first polarity. These clamps 60 are movable in that they can move in the vertical direction V. The clamps 60 serve to ensure that there is no air gap between the connecting lugs 14 with the first polarity and the connecting lugs 24 with the first polarity of the terminal device.For this purpose, the retainers 60 are lowered in the vertical direction V so that they press the connecting tabs 14 with the first polarity against the connecting tabs 24 with the first polarity. It should be noted that the retainers are hollow to allow the passage of a laser beam that enters. Fig. 5, represented by an arrow, to allow passage through it.

[0081] Similarly, during the positioning step, the components of the switching cell 1 are positioned in the welding device 56 such that the connecting tab 18 with the second polarity of the intermediate circuit capacitor 4, and optionally all its connecting tabs 18 with the second polarity, are supported by the support tools 58 of the welding device 56. The support tools 58 pass through the holes 32 in the legs 30 of the connection device 22, with a portion of the support tools 58 in Fig.The support tools 58 are shown with dashed lines to indicate their passage through the holes 32, which are also shown with dashed lines. The support tools 58 are thus in contact with the insulating medium 46, which is located between the legs 30 of the connection device 22 and the connecting lugs 18 with the second polarity. The passage of the support tool 58 through the hole 32 is facilitated by the fact that the hole 32 has a complementary shape to that of the support tool 58. The hold-down devices 60 of the welding tool 56 are then moved along the vertical direction V to press the connecting lug 18 with the second polarity through the insulating medium 46 against the connecting lug 16 with the second polarity. In other words, the connecting lug 18 with the second polarity and the connecting lug 16 with the second polarity are clamped and pressed between the support tools 58 on the one hand and the hold-down devices 60 on the other.The inclination of the free end 54 of the connecting flag 18 with the second polarity helps to ensure that no air gap is formed and that the connecting flag 18 with the second polarity is not bent in the opposite direction, i.e. at a distance from the connecting flag 16 with the second polarity.

[0082] After proper positioning, the first welding step of the manufacturing process takes place, in which the connecting tab 24 with the first polarity of the connection device 22 of the intermediate circuit capacitor 4 and the connecting tab 14 with the first polarity of the power module 2 are welded together. The connecting tabs 14 with the first polarity and the connecting tab 24 with the first polarity can be welded together by the laser beam.

[0083] The manufacturing process also includes a second welding step in which the connecting tab 18 is welded to the second polarity of the connecting device 17 of the intermediate circuit capacitor 4 and the connecting tab 16 is welded to the second polarity of the power module 2. It should be noted that in alternative embodiments, the second welding step can be performed before or simultaneously with the first welding step.

[0084] The present invention thus relates to a switching cell in which a power module and a DC link capacitor can be easily connected by layering a connecting device of one polarity and a terminal device of another polarity. Such layering of the connecting device and the terminal device serves to compensate magnetic fields and limit the stray inductance within the switching cell. Advantageously, such layering does not impede the welding processes of the power module terminals and the terminals of the DC link capacitor, since the terminal device has a special shape with a hole that allows suitable welding tools to press between the terminals of the power module and the terminals of the DC link capacitor.

[0085] Many modifications and other embodiments of the invention presented herein will be obvious to a person skilled in the art who is familiar with the teachings presented in the preceding descriptions and the accompanying figures. It is therefore understood that the invention is not limited to the specific embodiments disclosed and that modifications and further embodiments are included within the scope of the appended claims. Although certain terms are used herein, they are used only in a general and descriptive sense, and not for the purpose of limitation.

Claims

[1] Switching cell (1) for a motor vehicle, comprising a power module (2) and an intermediate circuit capacitor (4), wherein the power module (2) has at least one terminal (14) with a first polarity and at least one terminal (16) with a second polarity, wherein the intermediate circuit capacitor (4) comprises a connection device (17) with at least one connection terminal (18) with the second polarity, which is welded to the terminal (16) with the second polarity of the power module (2), wherein the intermediate circuit capacitor (4) comprises a connection device (22) comprising at least one leg (30) comprising at least one connection terminal (24, 24, 24B) with the first polarity in contact with the terminal (14) with the first polarity of the power module (2), wherein the leg (30) of the connection device (22) comprises the connection terminal (18) with the second polarity and the terminal (16) covered with the second polarity,wherein the connecting device (22) comprises at least one hole (32) in its leg (30) which faces the connecting flag (18) with the second polarity. [2] Switching cell (1) according to the preceding claim, wherein the hole (32) in the leg (30) of the connecting device (22) has a shape complementary to a shape of a support tool (58) of a welding device (56) of the switching cell (1). [3] Switching cell (1) according to one of the preceding claims, wherein the hole (32) in the leg (30) of the connection device (22) is centered within the leg (30) of the connection device (22) according to an orientation direction of the connection lugs (14, 16) of the power module (2). [4] Switching cell (1) according to one of the preceding claims, wherein the connection lugs (14, 16) of the power module (2) are in the same connection plane and are separated by a space, wherein the connection device (22) comprises a cover part (26) covering the space between the connection lugs (14, 16), wherein the cover part (26) is offset from the connection lug (24, 24, 24B) with the first polarity perpendicular to the connection plane. [5] Switching cell (1) according to the preceding claim, wherein the cover part (26) of the connection device (22) is located at a non-zero distance from the connecting tab (18) with the first polarity of the intermediate circuit capacitor (4). [6] Switching cell (1) according to one of the preceding claims in combination with claim 4, comprising at least one insulating means (46), wherein the insulating means (46) covers at least a part of the cover part (26) of the connection device (22). [7] Switching cell (1) according to the preceding claim, wherein the cover part (26) of the connection device (22) has a top (36), a bottom (38) and an edge (40) connecting the top (36) and the bottom (38), wherein the edge (40) faces the power module (2), wherein the insulating means (46) has a first part (48) that at least partially covers the bottom (38) of the cover part (26), a second part (50) that at least partially covers the top (36) of the cover part (26), and a third part (52) that at least partially covers the edge (40) of the cover part (26). [8] Switching cell (1) according to the preceding claim, wherein the first part (48) of the insulating medium (46) covering the underside (38) of the cover part (26) of the connection device (22) extends along the leg (30) of the connection device (22) between the connection device (22) and the connecting lug with the second polarity (18), wherein the first part (48) covers the hole (32) in the leg (30) of the connection device (22). [9] Switching cell (1) according to one of the preceding claims in combination with claim 7, wherein the second part (50) of the insulating medium (46) covering the top (36) of the cover part (26) of the connection device (22) extends to a point in a circumferential boundary of the hole (32) in the leg (30) of the connection device (22), wherein this point is closest to the edge (40) of the cover part (26) of the connection device (22). [10] Switching cell (1) according to one of the preceding claims, wherein the power module (2) comprises several phase modules (2A, 2B, 2C), each phase module (2A, 2B, 2C) having at least one terminal (14) with the first polarity and one terminal (16) with the second polarity, the terminal device (22) having a common body (28) and several legs (30) extending from the common body (28), each leg (30) being in contact with the terminal (14) with the first polarity of a given phase module (2A, 2B, 2C), each leg (30) having a hole (32). [11] Switching cell (1) according to one of the preceding claims, wherein a free end (54) of the connecting tab (18) with the second polarity of the intermediate circuit capacitor (4) is inclined to the connecting tab (16) with the second polarity of the power module (2). [12] Switching cell (1) according to one of the preceding claims, wherein the connecting tab (24, 24, 24B) with the first polarity of the connection device (22) comprises an extension (35) which includes a positioning hole (33). [13] Method for manufacturing a switching cell (1) according to one of the preceding claims, comprising a positioning step in which the connection device (22) is positioned so that it covers the connecting device (17), a first welding step in which the connecting tab (24, 24, 24B) with the first polarity and the connecting tab (14) with the first polarity are welded together, a second welding step in which the connecting tab (18) with the second polarity and the connecting tab (16) with the second polarity are welded together, wherein the second welding step comprises a partial step of positioning a support tool (58) of a welding device (56) through the hole (32) of the connecting device (22) in order to press the connecting tab (18) with the second polarity against the connecting tab (16) with the second polarity.

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