CAPACITIVE BLOCK WITH A FRAME MADE OF ELECTRICALLY INSULATING MATERIAL

Description

[0001] The present invention relates to a capacitive block, particularly for electrical equipment, for example, installed in a motor vehicle, especially an electric or hybrid one. Such electrical equipment may be an inverter, a voltage converter, or a battery charger.

[0002] As is well known, in a capacitive block, a capacitive element can be housed in a casing and embedded in a filling material that primarily serves to support and protect the capacitive element from moisture. Such a filling material is generally in the form of a resin. The capacitive element, for example, consists of films wrapped around the terminals of the capacitor. Typically, the capacitive element is completely embedded in the resin, so that the exterior of the capacitive block is formed by the outer walls of the casing and a resin face. Only electrical terminals extend beyond the resin from this resin face. However, in certain applications, particularly in electric or hybrid vehicles, the aim is to reduce the size of the electronic components. In this capacitive block structure, the casing and the resin occupy a potentially significant amount of space.In addition, it is necessary to leave a space between the capacitive element and the side walls of the case to allow the resin to flow out before it hardens.

[0003] We know of a capacitive block in which the casing extends to a height less than the height of the capacitive element. The casing then forms a basin just large enough to receive resin at one end of the capacitive block, which includes the electrical connection between an electrical terminal of the capacitive block and an electrode of the capacitive element.

[0004] In such a structure, the capacitive block's footprint is limited due to the low height of the housing. However, in this type of capacitive block design, the portion of the capacitive element exposed outside the resin is not protected from the external environment. Specifically, when an electrically conductive plate is attached to a second end of the capacitive element opposite the first end, the electrical plate is not, in principle, insulated from the surrounding environment.

[0005] The prior art relevant to the present invention can also be found in publications US 2002 / 051335 A1, US 2014 / 168901 A1 and EP 2 562 811.

[0006] Therefore, there is a need to electrically protect the elements of a capacitive block that are not otherwise protected by a resin.

[0007] To this end, the invention relates to a capacitive block comprising: at least one capacitive element; a first electrical conductor comprising at least one electrically conductive plate coming against a first end of the capacitive element so as to be electrically connected with the capacitive element; a first frame of electrically insulating material coming in correspondence with a peripheral edge of said conductive plate so as to electrically isolate said plate from an environment of the capacitive block.

[0008] By coming against the edges of the conductive plate, the first frame prevents the passage of an electric current between an electrically conductive element close to the capacitive block, through the air and / or along a creepage line.

[0009] In one embodiment, the first frame comprises a first portion configured to abut one face of the electrically conductive plate and a second portion extending transversely from the first portion to form a skirt around the conductive plate. This skirt thus forms an electrically insulating barrier against elements located near the conductive plate. Specifically, the skirt is positioned opposite the edges of the conductive plate. In particular, the face against which the first portion is positioned is opposite the first end of the capacitive element.

[0010] In one variant, the skirt stops at a height less than half, or even a third or a quarter, of the capacitive element's height from its first end. Thus, the skirt does not extend the full height of the capacitive element, thereby reducing the overall size of the capacitive block.

[0011] According to one variant, the skirt extends over a distance from the first portion of the first frame so as to prevent the circulation of an electric current through the air between the conductive plate and an environment of the capacitive block.

[0012] In one embodiment, the first electrical conductor comprises at least one connection portion extending from a peripheral edge of the conductive plate in a direction transverse to the conductive plate, and the first frame comprises a protective portion extending with respect to a face of the connection portion so as to electrically protect it from the environment of the capacitive block. In particular, the protective portion extends parallel to the face of the connection portion.

[0013] According to one variant, the first electrical conductor includes a first connection portion extending away from the capacitive element, and said first frame includes a first protection portion extending from the first portion of the first frame in a direction opposite to that of the skirt formed by the second portion of the frame.

[0014] According to one variant, the first electrical conductor includes a second connection portion extending from the conductive plate opposite the capacitive element, and said first frame includes a second protective portion formed by at least a part of the skirt.

[0015] In one embodiment, the first frame retains at least one second electrical conductor configured to connect to the first electrical connector in such a way as to connect the first electrical conductor to an electrical component other than the capacitive element, in particular to a power supply filtering element. Thus, the second electrical conductor is integrated within the first frame. The first frame therefore provides electrical insulation for the conductive plate and, thanks to the second electrical conductor, also provides an electrical connection between the first conductor and an element other than the capacitive block.

[0016] According to a particular variant, one end of a connecting portion, specifically the second connecting portion, is configured to come onto one end of the second electrical conductor of the first frame for an electrical connection.

[0017] In one embodiment, the capacitive block further comprises a frame-shaped electrical insulating film extending continuously along the inner edge of the first frame and radially inward. The insulating film notably increases the creepage distance between the conductive plate and an element near the capacitive block, particularly an element located opposite the conductive plate.

[0018] In one embodiment, the conductive plate is brought against at least one electrode of the capacitive element located at the first end of the capacitive element to be electrically connected to it. In particular, the connection between the conductive plate and the electrode of the capacitive element is protected by a varnish.

[0019] The invention further relates to electrical equipment, particularly configured for installation in a vehicle, comprising a capacitive block according to the invention, a power electronic module, and a cooling circuit. The conductive plate of the capacitive block is abutted against one face of the cooling circuit, and the power electronic module is abutted against the opposite face of the cooling circuit.

[0020] In particular, a power electronics module is an assembly comprising a plurality of semiconductor chips forming an electrical circuit, these chips being encapsulated in a single casing. More specifically, the power electronics module can form an inverter and includes components through which energy flows to power an electrical machine, for example, an electric motor configured to drive a vehicle. These components are designed to transform direct current (DC) into alternating current (AC) or vice versa. Such a power electronics module is notably configured to allow a controlled flow of electrical energy between a high-voltage power supply battery and the electrical machine.

[0021] In one embodiment, the electrical equipment includes a capacitive block comprising a first connection portion and a first protection portion. The first connection portion connects directly to the electrical terminals of the power electronic module, passing through a passage formed at least partially by an edge of the cooling circuit. The first protection portion of said first frame extends within said passage between said first connection portion and said cooling circuit. Thus, the first protection portion of the first frame provides electrical insulation between the first connection portion of the first electrical conductor and the cooling circuit. In particular, the first connection portion prevents the formation of an electric arc in the air between the first connection portion and the cooling circuit.

[0022] In one embodiment, the electrical equipment includes a layer of electrically insulating but thermally conductive material between the cooling circuit and the conductive plate, said layer of material being located in the central opening of the first frame. This material complements the electrical insulation of the conductive plate, insulating it from environmental elements located opposite the external face of the conductive plate. In particular, this material electrically insulates the conductive plate from the cooling circuit. However, this material also contributes to heat exchange between the conductive plate and the cooling circuit.

[0023] According to one embodiment, the electrical equipment forms an inverter, or a voltage converter or an electric battery charger.

[0024] The invention will be better understood and other details, features and advantages of the invention will become apparent upon reading the following description, given by way of non-limiting example with reference to the accompanying figures in which: [ Fig.1 ] represents an example of a capacitive block according to an embodiment of the invention; [ Fig.2 ] represents a capacitive element of the capacitive block of the figure 1 ; Fig.3 ] represents the capacitive block of the figure 1 without the frame; Fig.4 ] represents the framework of the capacitive block of the figure 1 ; Fig.5 ] illustrates a variant in which an additional insulating film is on the frame; [ Fig.6 ] represents a top view of the frame; Fig.7 ] represents an example of electrical equipment according to an embodiment of the invention; [ Fig.8 [ ] shows an example of an electric arc that is prevented in the electrical equipment of the figure 7 ; Fig.9 [ ] shows an example of a creepage line that is prevented in the electrical equipment of the figure 7 .

[0025] It should be noted that the figures present an example according to the invention in detail for implementation, said figures being of course able to serve to better define the invention where appropriate.

[0026] There figure 1 shows a capacitive block 100 according to an example of the invention. The capacitive block 100 comprises capacitive elements 105. Such a capacitive element 105 is illustrated in figure 2 The capacitive element 105 includes, in particular, an electrode formed at a first end 105a of the capacitive element 105. The electrode may extend over the entire first end 105a. The capacitive element 105 includes, in particular, a body 107 that protects the capacitive element 105. In particular, the body 107 may be electrically insulating. A second end 105b opposite the first end 105a includes an electrode of opposite polarity to the electrode of the first end 105a. The electrode may extend over the entire second end 105b. Alternatively, the capacitive element 105 could have its electrodes joined at a single end 105a, 105b. The capacitive element 105 is, for example, a film capacitor. The capacitive block 100 could comprise only a single capacitive element 105.

[0027] The capacitive block 100 further includes a first electrical conductor 110 having an electrically conductive plate 112 which is brought against the first end 105a of the capacitive element 105 for electrical connection. In particular, the conductive plate 112 is brought against the electrode of the first end 105a for connection. For this purpose, the plate 112 may include tabs 112L, more clearly visible in figure 3 These tabs, defined in plate 112, are to be soldered to the first end 105a. A varnish, particularly a silicone varnish, can be applied to the connection between the tabs 112L and the first end 105a, as well as to the entire surface of the first end 105a, for protection against moisture. However, when the first end 105a is without an electrode, the conductive plate can be brought against the first end 105a to ground the body 107 of the capacitive element 105.

[0028] The capacitive block 100 also includes a first frame 101 made of electrically insulating material, for example, plastic. The frame 101 is oriented against a peripheral edge of the conductive plate 112 so as to electrically insulate the plate 112 from the surroundings of the capacitive block 100. For example, as illustrated in figure 7 described later, when the capacitive block 100 is integrated into an electrical equipment 200, the frame 101 allows the conductive plate 112 to be electrically isolated from a cooling circuit 220 which is close to the capacitive block 100.

[0029] There figure 4 represents the frame 101 of the capacitive block 100. The frame 101 therefore includes a central opening delimited by an inner edge. The frame 101 includes, in particular, a first portion 101a configured to come against one face of the electrically conductive plate 112. The first portion 101a comes specifically against the face of the conductive plate 112 that is opposite the capacitive element 105. In particular, the first portion 101a includes the inner edge of the frame 101.

[0030] The frame 101 may further include a second portion 101b extending transversely from the first portion 101a to form a skirt 101b around the conductive plate 112. The skirt 101b contributes to the electrical insulation of the conductive plate 112 from its surroundings. Specifically, the skirt 101b is positioned opposite the edges of the conductive plate 112 and extends beyond the edges of the conductive plate 112 towards the second end 105b of the capacitive element 105. However, the skirt 101b does not reach the second end 105b of the capacitive element 105. Thus, the overall size of the capacitive block 100, particularly in a direction perpendicular to the skirt 101b, is limited. In the figures, the height of the skirt 101b, that is to say the distance between the edge of the skirt 101b which is connected to the first portion 101a and the extremal edge of the skirt 101b, is less than half the height of the capacitive element 105.The height of the capacitive element 105 is in particular the distance between the first end 105a and the second end 105b.

[0031] As illustrated for example in figure 3 The capacitive block 100 may include electrical terminals formed by connection portions 113, 114 of the first conductor 110. The connection portions 113, 114 extend from a peripheral edge of the conductive plate 112 in a direction transverse to said conductive plate 112. In particular, the first conductor 110 includes a first connection portion 113 extending from the conductive plate 112 away from the capacitive element 105. The first connection portion 113 is, for example, configured to be positioned against the terminals of a power electronic module, particularly in electrical equipment 200 described later. The first electrical conductor 110 may include a second connection portion 114 extending from the conductive plate 112 opposite the capacitive element 105.The second portion 114 is for example configured to come against an electrical conductor to connect the capacitive block to a power supply.

[0032] In order to protect the connection portions 113, 114, the frame 101 may include protective portions 103, 104 which extend along the connection portions 113, 114 so as to protect them electrically from the environment of the capacitive block 100. In particular, the frame 101 includes a first protective portion 103 which extends from the first portion 101a of the frame 101 in a direction opposite to that of the skirt formed by the second portion 101b of the frame 101. The first protective portion 103 extends opposite one face of the first connection portion 113 so as to cover it at least partially. In particular, the first protective portion 113 and the first connecting portion 103 overlap in a direction perpendicular to said face of the first connecting portion 113. The frame 101 includes a second protective portion 104 formed by the skirt 101b.The protective portions 103, 104 allow in particular electrical isolation between the connection portions 113, 114 and the nearby element 200, in particular by preventing the formation of an electric arc through the air or the circulation of a current along a creepage line.

[0033] By referring to the figure 6 , the frame 101 may include at least a second electrical conductor 120 configured to come on the first electrical conductor 110 so as to connect the first electrical conductor 110 with an electrical component other than the capacitive element 105, such as a filtering element of an electrical power supply.

[0034] In particular, the capacitive block 100 comprises a first positive conductor 110p and a first negative conductor 110n. The first conductors 110p and 110n are coplanar on one face of the capacitive block 100 where the first ends 105a of the capacitive elements 105 are located. The frame 101 comprises a second positive electrical conductor 120p and a second negative electrical conductor 120n, which connect respectively to the first positive conductor 110p and the first negative conductor 110n. The second electrical conductors 120 are thus integrated into the frame 101. The second electrical conductors 120 are, for example, held in place by the material of the frame 101 using clips, or by press fitting, or by overmolding. The first frame 101 therefore also serves to connect the first conductor 110 with an electrical component other than the capacitive element 105, such as a filtering element of an electrical power supply.In particular, one end 115 of the second connecting portion 114 is configured to meet one end 121 of the second electrical conductor 120 of the frame 101 for an electrical connection. Specifically, the connection area between the ends 115 and 121 is enclosed by a wall 106 integral with the insulating material of the frame 101, for electrical protection.

[0035] In an illustrated variant figure 5 An additional electrically insulating film 108 in the shape of a frame runs continuously along the inner edge of the frame 101, extending radially towards the interior of the frame 101, that is, into the central opening of the frame 101. The insulating film 108 serves, in particular, to increase the creepage distance along the first portion 101a of the frame 101, which runs from the conductive plate 112 to an element near the capacitive block 100, specifically the cooling circuit 220 located opposite the conductive plate, which will be described later. For example, the insulating film 108 is made of PET polyester and / or has a thickness of 200 microns, or even a thickness between 180 and 220 microns.

[0036] There figure 7 Figure 200 illustrates an example of electrical equipment comprising a capacitive block 100. The electrical equipment 200 further comprises a power electronics module 210 and a cooling circuit 220. The conductive plate 112 of the capacitive block 100 is abutted against one face of the cooling circuit 220, and the power electronics module 210 is abutted against the opposite face of the cooling circuit 220. The cooling circuit includes, in particular, a channel 221 located between the power electronics module 210 and the capacitive block 100, through which a coolant circulates. Specifically, the components 105, 200, and 220 are housed in a casing 225, only a portion of which is visible in Figure 1. figure 7 .

[0037] In particular, the first connection portion 113 of the first conductor 110 is directly connected to the electrical terminals 211 of the power electronic module 210. For this purpose, the first connection portion 113 passes through a gap formed by an edge of the cooling circuit 220 and a wall of the housing 225. The first protective portion 103 of the frame 101 also extends into this gap between the first connection portion 113 and the cooling circuit 220. Thus, the first protective portion 103 provides electrical insulation between the first connection portion 103 and the cooling circuit 220. This first connection portion prevents, in particular, the formation of an electrical arc in the air between the first connection portion 113 and the cooling circuit 220.

[0038] The electrical equipment 200 includes, in particular, a layer 230 of electrically insulating but thermally conductive material, more clearly visible in figures 8 And 9 This layer 230 is located between the cooling circuit 220 and the conductive plate 112. In particular, layer 230 is a Gap Pad®. The material layer 230 is specifically adjusted relative to the central opening of the frame 101, in order to improve the contact between the material 230 and the conductive plate 112, and thus improve heat dissipation between the conductive plate 112 and the cooling circuit 220.

[0039] The first part 101a of the frame 101 also has a function of limiting the compression of the material layer 230. For example, this first part 101a prevents the material layer 230 from being compressed by more than 30% of the initial thickness of the layer 230. In particular, the thickness of the first part 101a of the frame 101 is configured to prevent such compression of the layer 230. The first part 101a of the frame 101 has, for example, a thickness of 0.8 mm.

[0040] As schematically illustrated in figure 8 The frame 101, in particular the skirt 101b, improves the electrical insulation between the conductive plate 112 and the cooling circuit 220 by preventing the formation of an electric arc A1 through the air between the conductive plate 112 and the cooling circuit 220.

[0041] As schematically illustrated in figure 9 The insulating film 108 improves electrical insulation by increasing the creepage distance F2 between the conductive plate 112 and the cooling circuit 220. This creepage distance F2 starts at the conductive plate 112, follows the boundary between the material layer 230 and the first part 101a of the frame 101, then the boundary between the material layer 230 and the insulating film 108, and finally reaches the cooling circuit 220. Adding the insulating film 108 is more advantageous than increasing the overlap between the first portion 101a of the frame 101 because the insulating film 108 provides better heat dissipation than the frame 101.

[0042] According to one embodiment, with reference to figures 1 And 3A housing 150 can accommodate the second end 105b of the capacitive element 100 in order to receive a filling material to seal the second end 150b. The filling material is, in particular, an electrical insulating material, such as a resin. Specifically, the first end 105a is located outside said housing 150. Prior to filling the housing 150 with the filling material, in particular with the liquid resin, the capacitive element 105 is positioned in said housing 150. A spacer 151 extending from the bottom of said housing 150 then comes against the conductive plate 112, which forms a stop. The spacer 151 thus determines the distance between the first end 105a of the capacitive element 105 and the bottom of said housing 105.

Claims

1. Capacitive block (100) comprising: at least one capacitive element (105), a first electrical conductor (110) comprising at least one electrically conductive plate (112) positioned against a first end (105a) of the capacitive element (105) so as to be electrically connected with the capacitive element (105) a first frame (101) made of electrically insulating material positioned in correspondence with a peripheral edge of said conductive plate (112) so as to electrically insulate said plate (112) from an environment of the capacitive block (100) and wherein said first electrical conductor (110) includes at least one connection portion (113, 114) extending from a peripheral edge of said conductive plate (112) in a transverse direction relative to said conductive plate (112), and wherein said first frame (101) comprises a protection portion (103, 104) extending opposite a face of said connection portion (113, 114) so as to electrically protect it from an environment of the capacitive block (100).

2. Capacitive block (100) according to claim 1, wherein said first frame (101) comprises a first portion (101a) configured to come against a face of the electrically conductive plate (112) and a second portion (101b) extending transversely from said first portion (101a) so as to form a skirt (101b) around said conductive plate (112).

3. Capacitive block (100) according to claim 2, wherein the skirt (101b) extends over a distance from the first portion (101a) of the first frame (101) so as to prevent a current flow through the air between the conductive plate (112) and an environment of the capacitive block (100).

4. Capacitive block (100) according to any one of the preceding claims, wherein the first electrical conductor (110) comprises a first connection portion (113) that extends away from the capacitive element (105), and said first frame (101) comprises a first protection portion (103) that extends from the first portion (101a) of the first frame (101) in a direction opposite to that of the skirt formed by the second portion (101b) of the first frame (101).

5. Capacitive block (100), according to any one of claims 2 and 3, wherein the first electrical conductor (110) comprises a second connection portion (114) that extends from the conductive plate (112) opposite the capacitive element (105), and said first frame (101) comprises a second protection portion (104) formed by at least a part of the skirt (101b).

6. Capacitive block (100) according to any one of the preceding claims, wherein said first frame (101) holds at least a second electrical conductor (120) configured to come on the first electrical connector (110) so as to connect the first electrical conductor (110) with an electrical component other than the capacitive element (105), particularly with a filtering element of an electrical power supply.

7. Capacitive block (100) according to any one of the preceding claims, further comprising an electrically insulating film (108) in the form of a frame, coming continuously along the entire inner edge of the first frame (101) and extending radially inward from the first frame (101).

8. Capacitive block (100) according to any one of the preceding claims, wherein the conductive plate (112) comes against at least one electrode of the capacitive element (105) located at said first end (105a) of the capacitive element (105) to be electrically connected thereto.

9. Electrical equipment (200), particularly configured to be on board a vehicle, comprising a capacitive block (100) according to any one of the preceding claims, a power electronic module (210) and a cooling circuit (220); the conductive plate (112) of the capacitive block (100) coming against a face of the cooling circuit (220), the power electronic module (210) coming against an opposite face of the cooling circuit (220).

10. Electrical equipment (200) according to claim 9, comprising a capacitive block (100) according to claim 4, wherein the first connection portion (113) connects directly to the electrical terminals (211) of the power electronic module (220), passing through a passage formed at least in part by an edge of the cooling circuit (220), and wherein the first protection portion (103) of said first frame (101) extends in said passage between said first connection portion (113) and said cooling circuit (220).

11. Electrical equipment (200) according to claim 9 or 10, comprising a layer of material (230) that is electrically insulating but thermally conductive between the cooling circuit (220) and the conductive plate (112), said layer of material (230) coming into the central opening of the first frame (101).