CAPACITIVE BLOCK WITH A SPACER

Description

DOMAINE TECHNIQUE ET OBJET DE L'INVENTION

[0001] The present invention relates to a capacitive block, particularly for electrical equipment, for example, installed in a motor vehicle. 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 itself is, for example, made up 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 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 housing to allow for resin flow.

[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] However, the capacitive elements within the same model can have different heights due to inherent uncertainties in their manufacturing process. Thus, within the same capacitive block, the capacitive elements can vary in height. Furthermore, in an industrial manufacturing process, the heights of the capacitive elements can differ from one capacitive block to another, impacting the reproducibility of the dimensions of the manufactured capacitive blocks. This is particularly important in electrical equipment where the capacitive block must be cooled to dissipate the heat generated when it is powered by electricity. For this purpose, the electrical equipment is generally equipped with a cooling circuit. To optimize heat dissipation, one entire face of the capacitive block must be in contact with this cooling circuit.However, a difference in height between the capacitive elements of a capacitor block may prevent uniform contact between the block's face and the cooling circuit. Even if uniform heights are ensured within a capacitor block, a difference between capacitive blocks of the same model can cause disruptions in the dimensional chain of the electrical equipment that includes the capacitor block. A specific height for each capacitive block is not suitable for industrial manufacturing.

[0005] The relevant prior art can be found in documents DE102012205310 A1, WO2013 / 113691, WO 2012 / 105496 A1 and US 2018 / 316071 A1.

[0006] There is therefore a need for a capacitive block with a limited footprint while retaining some flexibility with respect to manufacturing uncertainties of the capacitive elements.

[0007] To this end, the present invention relates to a capacitive block, particularly for electrical equipment, comprising a housing; at least one capacitive element having a first end housed in said housing and a second end, which is opposite the first end and which extends out of said housing; a stop, said stop being fixed on the second end of the capacitive element; at least one spacer, coming against said stop, so as to determine the distance between the second end of the capacitive element and a bottom of said housing.

[0008] Thus, the spacer supports the capacitive element opposite the bottom of the housing. The height of the capacitive block between the bottom of the housing and the second end of the capacitive element is controlled by the spacer, so that the height of the capacitive block is controlled despite any uncertainty in the height of the capacitive elements. The bottom is, for example, a wall of the housing, particularly a perimeter wall, which is opposite the first end of the capacitive element.

[0009] According to one embodiment of the invention, a filling material, in particular a resin, at least partially fills said housing so as to provide a seal for the capacitive element at the first end of the capacitive element. In another variant, the filling material is an electrical insulator, thus providing electrical insulation of the first end from the housing receiving the first end.

[0010] The resin offers several advantages for use in a capacitive block. In particular, the resin is fluid when filling the housing. This fluidity allows for uniform distribution of the resin within the housing, between the capacitive elements, and at their connections. The resin hardens upon heating; it polymerizes. Therefore, after the polymerization stage, the resin becomes solid. This polymerization can be achieved by heating in an oven. The resin then surrounds one end of the capacitive element, sealing that end. Furthermore, the polymerized resin makes the bottom of the housing rigid and solid, providing effective support from the outer face of the bottom when the capacitive block is pressed against a heat sink.

[0011] According to one variant, the second end of the capacitive element extends outside of the filling material. Only a portion of the capacitive element is located within the housing.

[0012] According to one embodiment of the invention, the housing is formed by the base and a side wall extending from said base, delimiting an internal volume of said housing. The base of the housing includes the end of the capacitive element and simultaneously serves as electrical insulation between the capacitive element and the elastic member. In particular, the side wall extends towards the second end of the capacitive element.

[0013] In one variation, the side panel stops before the second end of the capacitive element. The housing therefore contains only the first end of the capacitive element. Specifically, the side panel stops at a height less than half, or even a third or a quarter, of the capacitive element's height. This reduces the size of the housing and, consequently, the overall footprint of the capacitive block.

[0014] In one variation, for rapid and uniform filling advantageous in an industrial manufacturing process, the side wall of the housing can be inclined outwards. This means that the area enclosed by the edge of the side wall, particularly in a plane parallel to the bottom of the housing, is larger than the area of ​​the bottom of the housing. The space occupied by the capacitive block depends, at least in part, on the extent of the housing's side walls. The shorter the side walls, the less space is occupied by the capacitive block. Nevertheless, in this variation, it is preferable to ensure a minimum span to allow for sealing of the first end of the capacitive element, which is embedded in the filling material.

[0015] In one variant, the filling material extends to a height less than that of the side wall. In particular, handling the capacitive block before polymerization is facilitated, as the risk of overflow is reduced.

[0016] According to one embodiment of the invention, the spacer extends from the bottom of the housing.

[0017] In one embodiment of the invention, the capacitive block comprises at least two spacers, which are evenly distributed across the bottom of the housing. This ensures that the contact points between the spacers and the stop are evenly distributed. In this way, an imbalance of the capacitive element relative to the spacers is prevented. Such an imbalance could cause the capacitive element to tilt, resulting in the outer face of the capacitive block, at the second end of the element, not being parallel to the bottom of the housing. This would be particularly detrimental when the capacitive block is pressed against a heat sink. Such pressing is achieved, for example, by applying pressure with a tensioned elastic element to the outer face of the housing bottom, thereby bringing the opposite outer face of the capacitive block against a heat sink.The heat dissipation resulting from the capacitive block being pressed against the heat sink is optimal when the plane of the pressed surface is parallel to the surface pushed by the elastic element. The at least two spacers ensure an equal distance between the stop and the bottom of the housing at every point along the stop. They thus help to keep the stop parallel to the bottom of the housing. The spacers can promote a uniform distribution of the pressing force applied by the elastic element.

[0018] According to one embodiment of the invention, the spacer has a cylindrical or conical shape.

[0019] In one embodiment of the invention, the first end of the capacitive element comprises a first electrode of the capacitive element, and the capacitive block comprises a first electrical terminal abutting said first electrode so as to connect electrically to the first electrode. This first electrical terminal has at least one opening through which said spacer passes. The opening in the first electrical terminal saves space. Indeed, it is then unnecessary to provide an overhang around the first electrical terminal in the bottom of the housing. Such an overhang would have accommodated the spacer so that it extends towards the stop, passing beside the first electrical terminal. Thanks to the opening in the first electrical terminal, this overhang is eliminated, thus reducing the overall size of the capacitive block. The opening can have various shapes. It can be a hole of any possible shape.The opening can be a notch formed from one edge of the first electrical terminal. The opening can be created by cutting or any other means. The opening allows the spacer to pass through so that it rests against the stop.

[0020] According to one embodiment of the invention, the stop comprises a second electrical terminal for connecting the capacitive block, said second electrical terminal being brought against a second electrode of the capacitive element so as to connect electrically to said second electrode of the capacitive element. In a variant, said second electrode is included in the second end of the capacitive element.

[0021] In one variant, the electrical connection between the second electrical terminal and the second electrode of the capacitive element is achieved by shooping. The shooping operation consists, in particular, of obtaining, by metal projection, a mechanical link and an electrical contact between the electrode of the capacitive element and the corresponding electrical terminal.

[0022] In one variant, the electrical connection, specifically the electrical connection made by shooping, between the second electrical terminal and the second electrode of the capacitive element is coated with a varnish to create a seal. Specifically, the varnish is applied to the entire second end of the capacitive element. The varnish provides a seal at the second end without obstruction. For example, a silicone varnish could be used.

[0023] Specifically, the first or second electrical terminal can be a conductive sheet or plate. In particular, the first or second electrical terminal connects the capacitive element to an element external to the capacitive block.

[0024] The invention further relates to a method for assembling a capacitive block comprising the steps of: to provide a capacitive element having a first end and a second end opposite each other, a stop being fixed to the second end, to mount said capacitive element in a housing by its first end so that the second end is outside of said housing, said assembly step including the placement of at least one spacer against said stop so as to determine the distance between the second end of the capacitive element and a bottom of said housing.

[0025] This avoids the need to manufacture and use an expensive, complicated, or bulky tool.

[0026] According to one embodiment, the process comprises the steps of: fill at least part of the housing with a fluid filling material so as to fill at least part, or even completely, the space between the capacitive element and a peripheral wall of the housing; harden the filling material, in particular by heating, in particular so as to fix the capacitive element in the housing.

[0027] Thus, the capacitive element is fixed in the housing and the first end of the capacitive block is sealed, with a limited footprint of the capacitive block.

[0028] The invention will be better understood with regard to the following illustrations: [ Fig.1 ] shows a capacitive block according to an example of an embodiment of the invention; [ Fig.2 ] shows a cover forming a housing for the capacitive block of the figure 1 ; Fig.3 ] shows an electrical terminal of the capacitive block of the figure 1 ; Fig.4 ] shows the capacitive block of the figure 1 without the hood; Fig.5 ] shows a capacitive element of the capacitive block.

[0029] There figure 1 Figure 1 shows a capacitive block 1 according to an embodiment of the invention. The capacitive block 1 is provided with a cover 14. This cover 14 forms a housing 3. The cover 14 includes, in particular, a base 15 and a side wall 17 extending from the base 15. The base 15 and the side wall 17 define an internal volume of the housing 3. The cover 14 receives in the housing 3 a first end 7 of the capacitive element 5. The first end 7 is embedded, in particular, in a filling material 12, such as resin, contained in said internal volume.

[0030] In the illustrated example, four capacitive elements 5 are arranged side by side in housing 3. In what follows, the example will be described with reference to only one 5a of the capacitive elements 5, the description readily applying to the other capacitive elements 5. An example of a capacitive element 5 is illustrated in figure 5 The capacitive element 5 is notably provided with a first electrode formed by its first end 7 and a second electrode of opposite polarity formed by the second end 9 opposite the first end 7. Alternatively, the capacitive element 5 could have its electrodes joined at a single end 7, 9. The capacitive element 5 is, for example, a film capacitor. The external curvature of the capacitive element 5 then arises from the manufacturing method of the capacitive element: the capacitive element 5 is notably made up of films wound into the shape of a flattened cylinder, the ends of the cylinders forming the electrodes of the capacitor, particularly after a metallization step.

[0031] The first end 7 of the capacitive element 5 is embedded in the filling material 12 contained in the housing 3. The second end 9 of the capacitive element 5 extends out of the housing 3. A stop 11 is fixed to the capacitive element 5 on the second end 9 of the capacitive element 5. Spacers 13 extend from the bottom 15 of the housing 3 to come against the stop 11, so as to determine the distance between the second end 9 of the capacitive element 5 and the bottom 15 of the housing 3. The illustrated example has four spacers 13, but in what follows the example will be described with reference to the two spacers 13a, 13b relating to the capacitive element 5a, the description being easily applied to the other capacitive elements 5 and their corresponding spacers 13.

[0032] Specifically, the capacitive block 1 includes a first electrical terminal 23 configured to connect the capacitive element 5 with an external element. In particular, the first electrical terminal 23 comes into contact with the first end 7 for electrical contact with the first electrode of the capacitive element 5. For this purpose, the first electrical terminal 23 includes, in particular, tabs 23L which are welded to the first electrode of the capacitive element 5. The first electrical terminal 23 further has openings 25 through which the spacers 13 pass to come into contact with the stop 11.

[0033] The capacitive element 5 is provided with the first electrical terminal 23 and the stop 11, to form a bare capacitive block 1N, that is to say a capacitive block 1 without a cover 14, for example as shown in figure 4 . Then the bare capacitive block 1N is mounted in the housing 3 of the cover 14. During this mounting, the first end 7 of the capacitive block 5 is inserted into the cover 14 so that the spacers 13 pass through the openings 25 of the first electrical terminal 23. The insertion of the capacitive element 5 into the cover 14 is stopped by the contact between the heads of the spacers 13 and the stop 11. The positioning of the spacers 13 in the cover 14 is adapted to correspond with the locations of the openings 25. However, the spacers 13 are located in the free space between the capacitive elements 5 and the bottom edge 15 of the housing 3, that is, in particular between the capacitive elements 5 and the side wall 17. Thus, once mounted in the housing 3, the bare capacitive block 1N is supported by the spacers 13. In particular, it remains a space between the bottom 15 of housing 3 and the first electrical terminal 23.In other words, the capacitive element 5 equipped with the first electrical terminal 23 is held in suspension by the spacers 13.

[0034] In particular, the side wall 17 of the hood 14 extends to a height which allows the filling material 12 to encompass the first electrical terminal 23 and the first end 7 of the capacitive element 5.

[0035] The stop 11 includes, in particular, a second electrical connection terminal 27 for the capacitive block 5. Like the first electrical connection terminal 23, the second electrical connection terminal 27 is specifically configured to connect the capacitive element 5 to an external element. To this end, the second electrical connection terminal 27 is brought against the second end 9 of the capacitive element 5, against the second electrode of the capacitive element 5, which is formed by the second end 9. Specifically, a varnish is applied to the entire second end 9 of the capacitive element 5 to provide a seal at that end.

[0036] In particular, the first electrical connection terminal 23 includes ends 31 for connecting to a power electronic module. In particular, the second electrical connection terminal 27 includes ends 33 for connecting to a power supply, in particular a battery.

[0037] As seen in figure 2 , the spacers 13 are distributed regularly on the bottom, 15 in order to allow stable holding of the stop 11 and therefore of the capacitive elements 5.

[0038] The spacers 13 are typically conical with a polygonal cross-section. However, they could be of a different shape, for example, cylindrical, conical, or with a rounded cross-section. A shape that tapers towards the stop 11 offers the advantage of a solid base and easy insertion during assembly.

[0039] The example of capacitive block 1 described is also similar to that described in European patent application publication EP3197035.

Claims

1. Capacitive block (1), particularly for electrical equipment, comprising: - a housing (3), - at least one capacitive element (5) having a first end (7) housed in said housing (3) and a second end (9), which is opposite to the first end (7) and which extends outside said housing (3), - a stop (11), said stop (11) being fixed on the second end (9) of the capacitive element (5), - at least one spacer (13), coming against said stop (11), so as to determine the distance between the second end (9) of the capacitive element (5) and a bottom (15) of said housing (3).

2. Capacitive block (1) according to claim 1, wherein a filling material (12), particularly a resin, fills at least partially said housing (3) so as to provide sealing of the capacitive element (5) at the level of the first end (7) of the capacitive element (5).

3. Capacitive block (1) according to claim 2, wherein the second end (9) of the capacitive element (5) extends outside said filling material (12).

4. Capacitive block (1) according to any one of the preceding claims, wherein said spacer (13) extends from the bottom (15) of the housing (3).

5. Capacitive block (1) according to any one of the preceding claims, comprising at least two spacers (13), and wherein said spacers (13) are regularly distributed on the bottom (15) of the housing (3).

6. Capacitive block (1) according to any one of the preceding claims, wherein said spacer (13) has a cylindrical or conical shape.

7. Capacitive block (1) according to any one of the preceding claims, wherein the first end (7) of the capacitive element (5) comprises a first electrode of the capacitive element (5), and the capacitive block (1) comprises a first electrical terminal (23) coming against said first electrode so as to electrically connect to the first electrode, said first electrical terminal (23) having at least one opening (25), through which said spacer (13) passes.

8. Capacitive block (1) according to any one of the preceding claims, wherein said housing (3) is formed by the bottom and a lateral wall (17) extending from said bottom (15), delimiting an internal volume of said housing (3).

9. Capacitive block (1) according to any one of the preceding claims, wherein said stop (11) comprises a second electrical connection terminal (27) of the capacitive block (1), said second electrical terminal (27) coming against a second electrode of the capacitive element (5) so as to electrically connect to said second electrode of the capacitive element (5).

10. Method of assembling a capacitive block (1) comprising the steps of: - providing a capacitive element (5) having a first end (7) and an opposite second end (9), a stop (11) being fixed to the second end (9); mounting said capacitive element (5) in a housing (3) by its first end (7) so that the second end (9) is outside said housing (3); said mounting step comprising pressing at least one spacer (13) against said stop (11) so as to determine the distance between the second end (9) of the capacitive element (5) and a bottom (15) of said housing (3).

11. Assembly method according to the preceding claim comprising a step consisting of: - connecting a first electrical terminal (23) of the capacitive block (1) to a first electrode of the capacitive element (5) included in the first end (7), and connecting a second electrical terminal (27) of the capacitive block (1) to a second electrode of the capacitive element (5) included in the second end (9), said second electrical terminal (27) being included in said stop (11); and wherein the mounting step comprises passing the spacer (13) through an opening (25) of the first electrical terminal (23) to come to rest against said stop (11).

12. Assembly method according to claim 11, comprising the steps of: - filling at least partially the housing (3) with a fluid filling material (12) so as to fill at least partially, or even completely, the space between the capacitive element (5) and a peripheral wall (15,17) of the housing (3); - hardening the filling material (12), particularly by heating.