Capacitor and electronic assembly with improved heat dissipation

Abstract

Capacitor (10) comprising the following: a first winding element (50) comprising a first dielectric layer (42) and a first conductive layer (39), wherein the first conductive layer (39) superimposes at least one section of the first dielectric layer (42), a second winding element (52) comprising a second dielectric layer (37) and a second conductive layer (40), wherein the second conductive layer (40) overlaps at least a section of the second dielectric layer (37), wherein the second winding element (52) is partially or completely nested with the first winding element (50), a dielectric housing (12) to contain or limit the first winding element (50) and the second winding element (52) at least radially, wherein the dielectric housing (12) has a top surface (14) and a bottom surface (18) opposite the top surface (14), a first metallic element (54) having a generally flat, radially extending surface for electrical and mechanical contact with an upper section of the first conductive layer (39), a second metallic element (56) having a generally flat, radially extending surface for electrical and mechanical contact with a lower section of the second conductive layer (40), a first conductor (22) coupled to the first metallic element (54) and extending through the top surface (14) characterized in that the underside surface (18) of the dielectric housing (12) comprises the second metallic element (56) which has an exposed outer surface or a metallic pad, that the first conductor (22) has generally flat surfaces (51) parallel or coplanar to the top surface (14) and generally flat bottom surfaces (53) that are parallel or coplanar to the bottom surface (18), wherein a portion of the first conductor (22) extends perpendicular to the generally flat surfaces (51, 53) along the housing (12) to terminate in another metallic pad (55) or a substantially planar bottom surface (53) that is substantially parallel or coplanar to the bottom surface (18), and that a second conductor (24) extends through the top surface (14), is spaced apart from the first conductor (22), is connected via the first metallic element (54) to the upper section of the first conductive layer (39), has generally flat surfaces (51) parallel or coplanar to the top surface (14) and generally flat bottom surfaces (53) that are parallel or coplanar to the bottom surface (18), wherein a portion of the second conductor (24) extends perpendicular to the generally flat surfaces (51, 53) along the housing (12) to terminate in another metallic pad (55) or a substantially planar bottom surface (53) that is substantially parallel or coplanar to the bottom surface (18).

Description

Field of invention

[0001] This disclosure relates to a capacitor with improved heat dissipation and an electronic assembly with one or more capacitors with improved heat dissipation. State of the art

[0002] In certain prior art, a capacitor or an electronic assembly containing one or more capacitors may have inadequate heat dissipation, reducing the lifespan or maximum power output of an electronic circuit. In certain film capacitors, heat dissipation is limited by the capacitor's housing design. Reference is made to the disclosure in US 8,098,479 B1, which is considered a generic disclosure, according to which two films, each coated with a conductive layer, are placed one on top of the other and wound up. One of the conductive layers extends to a first edge of the film, and the other to the opposite edge. A conductive layer is welded to each edge and electrically connected by conductors to external contacts located at an axial end of the capacitor, which extend through the housing to the outside.The first (upper) edge of the foil is adjacent to the contacts, and the conductive layer welded to it is thus connected to the corresponding contact (located at the top of the housing) by a relatively short conductor. The second edge of the foil is spaced away from the contacts, and its conductive layer is connected to the corresponding contact by a conductor running centrally through the wound foil. Heat dissipation is therefore only possible through the capacitor housing and, to a minimal extent, through the conductors and the contacts.

[0003] Therefore, there is a need for a capacitor or electronic assembly with improved heat dissipation. Brief description

[0004] The present invention is defined by the patent claims.

[0005] A capacitor comprises a first winding element, the first winding element having a first dielectric layer and a first conductive layer. The first conductive layer overlaps at least a portion of the first dielectric layer. A second winding element comprises a second dielectric layer and a second conductive layer. The second conductive layer overlaps at least a portion of the second dielectric layer. The first winding element is partially or completely nested with the second winding element. A dielectric housing or shell is adapted to contain or border the first and second winding elements at least radially. A first metallic element has a generally flat, radially extending surface for electrical and mechanical contact with an upper portion of the first conductive layer.A second metallic element has a generally flat, radially extending surface for electrical and mechanical contact with a lower section of the second conductive layer. A first conductor is coupled to the first metallic layer and extends through a top surface. A second conductor extends through the top surface, spaced apart from the first conductor. The second metallic element is exposed to serve as an auxiliary conductor. Brief description of the drawings Fig. Figure 1 is a perspective view of an embodiment of an electronic assembly with capacitors arranged in series and with a capacitor shown in a pulled-out format separated from the electronic assembly (without any inclusion). Fig. 2 is a flat view or top view of a single capacitor of the Fig. 1, the inner windings illustrated as dashed lines. Fig. Figure 3 shows a cross-section of the capacitor. Fig. 2 along the reference line 3-3 of the Fig. 2. Fig. Figure 4 shows a perspective view of the bottom of a capacitor. Fig. 2. Fig. Figure 5 illustrates a flat view or top view of an embodiment of a capacitor not covered by the claims, illustrating the inner windings as translucent. Fig. Figure 6 shows a cross-section of the capacitor. Fig. 5 along the reference line 6-6 of the Fig. 5. Fig. Figure 7 shows a perspective view of the bottom of a capacitor. Fig. 5. Fig. Figure 8 shows a cross-section of an electronic assembly housed in an enclosure. Fig. Figure 9 illustrates a flat view or top view of another embodiment of a capacitor not covered by the claims, illustrating the internal windings as translucent. Fig. Figure 10 shows a cross-section of the capacitor of the Fig. 9 along the reference line 10-10 of the Fig. 9. Fig. Figure 11 shows a perspective view of the bottom of a capacitor. Fig. 9.

[0006] Identical reference symbols in different drawings indicate the same elements. Detailed description

[0007] A capacitor 10 housing comprises one or more conductors (for example, 22, 24), terminals or electrodes, and an enclosure, shell, or skin. The housing can be designed for optimal or improved heat dissipation from the capacitor 10 to the environment, a printed circuit board 28 on which the capacitor 10 is mounted, or a casing (800 in Fig. 8) or housing in which the capacitor 10 is housed. The capacitor 10 may be a film capacitor or otherwise manufactured or constructed.

[0008] Fig. Figure 1 illustrates an embodiment of an electronic assembly 11 comprising a printed circuit board 28 having one or more conductors and one or more capacitors 10 mounted on the printed circuit board 28. The printed circuit board has a first side 30 and a second side 32 opposite the first side 30. As shown, the capacitors 10 are arranged in one or more rows (26, 34) on both sides (30, 32) of the printed circuit board 28, but the capacitors 10 can be arranged in other configurations on one or both sides (30, 32) of the printed circuit board 28. The printed circuit board 28 can have one or more connectors, such as one or more metallic connectors 38, or a multi-conductor connector 36.

[0009] The capacitors 10 can be soldered onto a printed circuit board 28, such as a printed circuit board 28. In one configuration, the printed circuit board 28 is optionally constructed with thick traces (for example, equal to or larger than 8-ounce traces, or with a thickness greater than the conventional metallic traces on the printed circuit board 28) to conduct sufficient amounts of electrical current for certain electronic power circuits. Mounting the capacitors 10 onto the printed circuit board 28 in this way allows heat to be transferred or communicated from the base 20 of the capacitor 10 through the printed circuit board 28 to any heat sink or heat sink inclusion connected to the printed circuit board 28.

[0010] As in Fig. 2 and Fig. As illustrated in Figure 3, a capacitor 10 in one embodiment comprises a first winding element 50 and a second winding element 52. The first winding element 50 is partially or completely interleaved with the second winding layer. In one embodiment, the first winding element 50 comprises a first dielectric layer 42 and a second conductive layer 39. The first conductive layer superimposes at least a portion of the first dielectric layer 42. A second winding element 52 comprises a second dielectric layer 37 and a second conductive layer 40. The second conductive layer 40 superimposes at least a portion of the second dielectric layer 42.

[0011] A dielectric housing 12 is adapted to radially contain or border the first winding element 50 and / or the second winding element 52. The dielectric housing 12 can, for example, comprise a dielectric skin or a dielectric shell.

[0012] A first metallic element 54 has a generally flat, radially extending surface for electrical and mechanical contact with an upper section of the first conductive layer 39. A second metallic element 56 has a generally flat, radially extending surface for electrical and mechanical contact with a lower section of the second conductive layer 40. A first conductor 22 is coupled to the first metallic element 54 and extends through a top surface 14.

[0013] In one configuration, the first dielectric layer 42 and the second dielectric layer 37 are formed from polyethylene, a plastic or polymer that is substantially elastically deformable or generally compliant. The first conductive layer 39 and the second conductive layer 40 can be a metal foil layer or a metallized layer formed by electroless deposition, sputtering, electroplating, or another process. The first winding element 50 has a side edge of the first dielectric layer 42 that is not metallized or covered by a first conductive layer 39, and the second winding element 52 has a side edge that is not metallized or covered by a second conductive layer 40. The first winding element 50 and the second winding element 52 are stacked on top of each other and wound around a dielectric coil or shape (for example, a detachable or captive shape).

[0014] Fig. 2 and Fig. Figure 3 shows a capacitor 10 in accordance with the disclosure. The capacitor 10 has conductors extending from the top 16 of the capacitor 10, as well as a metal pad located on the bottom 20 of the film capacitor 10. The bottom 20 of the capacitor 10 has a second metallic element 56 or metal pad connected to the second winding element 52 (or the second conductive layer 40) for improved heat dissipation. Similarly, the connecting conductors are configured in a substantially flat configuration near or at the top 16 of the capacitor 10 for improved heat dissipation. This capacitor 10 was designed for optimal heat transfer from the body of the capacitor 10 via thermally efficient axial heat flow through the first metallic element 54, the second metallic element 56, and associated conductors.The second metallic element 56, or exposed metal pad, on the base 20 of the cap can be soldered or made in contact (for example, directly or indirectly with thermally conductive material or grease) with a surface, receiving pad, or conductor that can transfer heat (for example, to a heat sink or an inclusion 800). The top surface 16 of the capacitor 10 was also designed to allow the flat-configured conductors (22, 24) to press upwards against a heat sink or an inclusion 800 and to dissipate heat generated in or by the capacitor 10. The conductors (22, 24) are then configured to allow the electrical and mechanical connection to the circuit board 28.In an alternative embodiment, the capacitor 10 can also function without the base 20, which has a metallic interface or an exposed metal pad for direct or indirect contact with a receiving pad, a heat sink or conductor tracks on the circuit board 28.

[0015] How best to Fig. 3 and Fig. As illustrated in Figure 4, the dielectric housing 12 has a top surface 14 and a bottom surface 18 opposite or connected to the top surface 14. A first metallic element 54 has a generally flat, radially extending surface (for example, a first annular surface) to electrically and mechanically contact an upper section of the first conductive layer 39. A second metallic element 56 has a generally flat, radially extending surface (for example, a second annular surface) to electrically and mechanically contact a lower section of the second conductive layer 40. A first conductor 22 is coupled to the first conductive layer 39 via a first metallic element 54 and extends through the top surface 14. A second conductor 24 extends through the top surface 14. The second conductor 24 is spaced apart from the first conductor 22.In one embodiment, the second conductor 24 is coupled to an upper section of the first conductive layer 39 via the first metallic element 54.

[0016] The dielectric housing 12 has a bottom surface 18 opposite the top surface 14. The first conductor 22 generally has flat top surfaces 51 substantially parallel or coplanar to the top surface 14, and generally flat bottom surfaces 53 that are parallel or coplanar to the bottom surface 18. The second conductor 24 generally has flat top surfaces 51 substantially parallel or coplanar to the top surface 14, and generally flat bottom surfaces 53 that are substantially parallel or coplanar to the bottom surface 18. In one embodiment, the first conductor 22 and the second conductor 24 each terminate in a metal pad 55 for mounting a corresponding pad or trace on a printed circuit board.The dielectric housing 12 has a bottom surface 18 opposite the top surface 14; the bottom surface 18 includes the second metallic element 56 with an exposed outer surface or a metal pad. Fig. Figure 4 illustrates an exposed metal pad connected to the second metallic element 56. The metallic pad can be soldered to a corresponding mounting pad or a conductor track on the circuit board 28. In one embodiment, the second metallic element 56 has its circumference covered or is adhered to a dielectric circumferential element 57 or a wall.

[0017] Fig. 2 and Fig. Figure 3 illustrates how the space-saving conductors (24, 26) are bent to occupy the so-called corners of the capacitor 10. In a standard design (not shown), a film capacitor would be placed in a rectangular plastic container or box filled with epoxy to secure the windings. In this configuration, the rectangular box of the capacitor 10 has been replaced by a generally elliptical configuration (for example, an elliptical, cylindrical, or elongated container) to utilize the corner space and minimize the overall mounting footprint of the capacitor 10. The footprint is reduced because, if the capacitor 10 were housed in a square box, the conductor would have to extend outside this footprint. Fig. Figure 1 illustrates how rows (26, 34) of capacitors 10 are nested close together using the space-saving conductor configuration (22, 24) to build a capacitor bank.

[0018] Fig. 5 to Fig. Figure 7 illustrates an alternative embodiment of a capacitor 110. The capacitor 110 of Fig. 5 to Fig. 7 is similar to capacitor 10 from Fig. 2 to Fig. 4, with the exception that the second conductor is 124 of the Fig. 6 of the second leader 24 of the Fig. 3 distinguishes. Same reference symbols in Fig. 1 to inclusive Fig. 7 indicate identical elements.

[0019] As in Fig. 5 and Fig. As illustrated in Figure 6, the first conductor 22 is connected to the upper section of the first conductive layer 39 via the first metallic element 54, for example at the junction 129. The second conductor 124 is coupled to a lower section of the second conductive layer 40 via the second metallic element 56 and the inner conductor 127. The second metallic element 56 can be located in the capacitor of the Fig. Whether or not 5 to 7 are exposed. In Fig. 7 is, for example, the second metallic element 56 covered by the lower dielectric element 157, which may be integral or continuous with the dielectric casing 12.

[0020] Fig. Figure 8 illustrates the electronic assembly 11 of the Fig. 1, which is housed in an enclosure of 800. In Fig. In Figure 1, the inclusion 800 was omitted to better show the electronic assembly 11. The same reference numerals are used in the Fig. 1 and Fig. 8 identical elements.

[0021] Fig. Figure 8 illustrates an enclosure 800 for housing the electronic unit 11, although any other enclosure or compartment can be manufactured to house or surround the capacitors (for example, 10, 110, or 210) to effectively conduct or transfer heat from the top 16 of the conductors (for example, 22, 24, 124). In this configuration, the enclosure has a first enclosure section and a second enclosure section, which are mirror images of each other. The circuit board 28 has capacitors (for example, 10, 110, or 210) on the first side 30, the second side 32, or on both sides.

[0022] As in Fig. As illustrated in Figure 8, the enclosure 800 comprises a first inner enclosure section 801, a first outer enclosure section 805, a second inner enclosure section 802, and a second outer enclosure section 806. The first inner enclosure section 801 and the second inner enclosure section 802 can be connected to each other by fasteners, adhesive, or some other securing mechanism to hold or house the electronic assembly 11. The first outer enclosure section 805 is capable of fitting to or sealing the first inner section 801 such that coolant or fluid can be retained or circulated within a chamber, conduit, or passage formed by connecting the first outer enclosure section 805 and the first inner enclosure section 801.The second outer enclosure section 806 is capable of fitting to or sealing the second inner section 802 in such a way that coolant or fluid can be retained or circulated within a chamber, conduit, or passage formed by connecting the second outer enclosure section 806 and the second inner enclosure section 802. Fig. Figure 8 illustrates arrows (803, 804) where the fluid or coolant (for example, water or ethylene glycol or a solution thereof) would flow to cool the condensers (for example, 10, 110 or 210).

[0023] The first inner enclosure section 801 engages with or touches the first conductors 22 and second conductors (for example, 24 or 124, if present) of a first set (for example, rows 26) of capacitors (for example, 10, 110, or 210) such that heat can flow axially (for example, upwards) away from the electronic assembly 11 via the enclosure 800. The second inner enclosure section 802 engages with or touches the first conductors 22 and second conductors 24 of the second set (for example, rows 34) of capacitors (for example, 10, 110, 210) such that heat can flow axially (for example, downwards) away from the electronic assembly 11 via the enclosure 800. The fluid or coolant can transfer or remove heat from the electronic assembly 11 or the capacitors (for example 10, 110, 210) by circulating or pumping the fluid through a cooler, for example to the ambient air.Furthermore, mounting or soldering the capacitors (for example, 10, 110, or 210) to the circuit boards 28 via pads 55, an exposed section of the second metallic element 56, or both, allows heat to be transferred or conducted away from the bottom 20 of the capacitor through the circuit board 28 as well as through the top 16 of the capacitor 10 via a heat sink (for example, a fluid-cooled heat sink or chamber) above the capacitors.

[0024] In an alternative embodiment, a heat interface material (TIM, in Fig. (8 not shown) into or between the capacitor leads (for example, 22, 24, 124) or the top 16 of the capacitor (for example, 10, 110, or 210) and the first inner inclusion section 801 or the inclusion 800. Similarly, TIM can be inserted between or between the capacitor leads (22, 24, 124) or the bottom 18 of the capacitor through the circuit board 28 over the heat sink (for example, fluid-cooled heat sink or chamber) below the capacitors. A thermal interface material (TIM) can comprise a polymer, elastomer, adhesive, or plastic, such as silicone. The thermal interface material can be injected, injection-molded, or forced into any air gap between the capacitors. The TIM can provide electrical insulation between the terminals (22, 24) and the inclusion 800 of the assembly.The TIM can also fill gaps between adjacent capacitors (for example, 10, 110 or 210) to provide cooling to the circuit board 28 by heat conduction outside to the enclosure 800.

[0025] Fig. Figures 9 to 11 inclusive provide an illustration of another alternative embodiment of capacitor 210. The capacitor 210 of Fig. 9 to and including Fig. 11 is the capacitor 10 of the Fig. 1 to 3 inclusive are similar, except that the second conductor 24 has been eliminated and the exposed metal pad of the second metallic element 56 is used as an auxiliary terminal or clamp for the capacitor 210.

[0026] The second conductor 24 is not required because the second metallic element 56 can be exposed to serve as an auxiliary conductor or electrode. The base 20 of the capacitor 210 has an optional exposed metallic surface or metal pad that provides additional heat dissipation for greater power dissipation (for example, in potentially smaller capacitor 210 packages than otherwise possible).

[0027] In each embodiment described in this document, the capacitor and electronic assembly are well suited to directly mount certain capacitors (for example, medium to small capacitors) to a printed circuit board, while facilitating heat dissipation from the capacitor. Heat can be dissipated or flow from the base of the capacitor directly or indirectly through the printed circuit board and then to the inclusion. An exposed pad of the second metallic element (for example, 56) can provide a surface for efficient heat transfer to a metallic trace or metallic fill (for example, heavy copper fill) on the printed circuit board. Heat can also be dissipated or flow from the top of the capacitor directly to the inclusion or to the surrounding air.The enclosure may include a heat sink with a jacket or a cooling chamber for cooling the enclosure, one or more capacitors, and an electronic assembly.

[0028] The capacitor's conductors are also arranged via pads or traces for efficient heat dissipation to the ambient air, the enclosure, and the circuit board. Because one or more capacitors in the electronic assembly can be kept cooler, the electronic assembly (such as an inverter or control device) can operate reliably for a longer lifespan or handle greater current or power than would otherwise be possible.

[0029] In view of the preferred embodiment, it becomes clear that different modifications can be made without deviating from the scope of the invention as defined in the attached claims.

Claims

[1] Capacitor (10) comprising the following: a first winding element (50) comprising a first dielectric layer (42) and a first conductive layer (39), wherein the first conductive layer (39) superimposes at least one section of the first dielectric layer (42), a second winding element (52) comprising a second dielectric layer (37) and a second conductive layer (40), wherein the second conductive layer (40) overlaps at least a section of the second dielectric layer (37), wherein the second winding element (52) is partially or completely nested with the first winding element (50), a dielectric housing (12) to contain or limit the first winding element (50) and the second winding element (52) at least radially, wherein the dielectric housing (12) has a top surface (14) and a bottom surface (18) opposite the top surface (14), a first metallic element (54) having a generally flat, radially extending surface for electrical and mechanical contact with an upper section of the first conductive layer (39), a second metallic element (56) having a generally flat, radially extending surface for electrical and mechanical contact with a lower section of the second conductive layer (40), a first conductor (22) coupled to the first metallic element (54) and extending through the top surface (14) characterized by , that the underside surface (18) of the dielectric housing (12) includes the second metallic element (56) which has an exposed outer surface or metallic pad, that the first conductor (22) has generally flat surfaces (51) parallel or coplanar to the top surface (14) and generally flat bottom surfaces (53) that are parallel or coplanar to the bottom surface (18), wherein a portion of the first conductor (22) extends perpendicular to the generally flat surfaces (51, 53) along the housing (12) to terminate in another metallic pad (55) or a substantially planar bottom surface (53) that is substantially parallel or coplanar to the bottom surface (18), and that a second conductor (24) extends through the top surface (14), is spaced apart from the first conductor (22), is connected via the first metallic element (54) to the upper section of the first conductive layer (39), has generally flat surfaces (51) parallel or coplanar to the top surface (14) and generally flat bottom surfaces (53) that are parallel or coplanar to the bottom surface (18), wherein a portion of the second conductor (24) extends perpendicular to the generally flat surfaces (51, 53) along the housing (12) to terminate in another metallic pad (55) or a substantially planar bottom surface (53) that is substantially parallel or coplanar to the bottom surface (18). [2] Capacitor (10) according to claim 1, wherein the second metallic element (56) is flat and wherein a dielectric rim (57) is electrically insulated from the second metallic element (56). [3] Capacitor (10) according to claim 1, wherein the first conductor (22) terminates in the other metallic pad (55) for mounting on a printed circuit board (28), and wherein the second conductor (24) terminates in the other metallic pad for mounting on the printed circuit board (28). [4] Capacitor (10) according to claim 1, wherein the second metallic element (56) extends radially outwards from a central axis of the housing (12). [5] Capacitor (10) according to claim 1, wherein the first conductor (22) and the second conductor (24) extend radially outwards diagonally from or near the central axis of the housing (12). [6] Capacitor (10) according to claim 1, wherein the first winding element (50) and the second winding element (52) each have a spiral cross-section of their respective conductive layer (39, 40). [7] Electronic assembly (11) comprising the following: a printed circuit board (28) which has one or more conductive traces, a capacitor (10) according to one of the preceding claims for mounting on the printed circuit board (28). [8] Electronic assembly according to claim 7, wherein the metallic pad of the second metallic element (56) is soldered to a corresponding mounting pad or conductor track on the printed circuit board (28). [9] Electronic assembly according to claim 7, further comprising several capacitors (10) according to any one of claims 1 to 6, arranged in one or more rows on the printed circuit board (28). [10] Electronic assembly according to claim 7, further comprising a first set of capacitors (10) according to any one of claims 1 to 6, mounted on a first side (30) of the printed circuit board (28), and a second set of capacitors (10) according to any one of claims 1 to 6, mounted on a second side (32) of the printed circuit board (28) opposite the first side (30). [11] Electronic assembly according to claim 10, further comprising: an enclosure (800) having a first enclosure section (801, 805) for engaging in or touching the first conductors (22) and second conductors (24) of the first set of capacitors (10) and a second enclosure section (802, 806) for engaging in or touching the first conductors (22) and second conductors (24) of the second set of capacitors (10) such that heat can flow axially away from the electronic assembly via the enclosure (800).

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