System for capacitor of inverter of electric vehicle

Abstract

A system for a capacitor of an inverter of an electric vehicle. A system includes an inverter for converting direct current (DC) power from a battery to alternating current (AC) power to drive an electric machine, where the inverter includes: a capacitor assembly including: a planar busbar including a first DC busbar and a second DC busbar; a capacitor on the same side of the first DC busbar and the second DC busbar, the capacitor including a first end cap extending in a direction substantially perpendicular to a longitudinal direction of the planar busbar; and a first connection plate having a shape designed to transfer heat from the first end cap of the capacitor and the first connection plate to a first outer surface.

Description

[0001] Cross-reference to related applications

[0002] This application claims the priority of U.S. Provisional Patent Application No. 63 / 658,919, filed June 12, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The various embodiments of this disclosure generally relate to a capacitor, and more particularly, to a system for thermal management of a capacitor for an inverter in an electric vehicle. Background Technology

[0004] Thermal management is considered a key technology aspect of electric vehicle systems. The cooling modules of the inverter system control the performance and efficiency of the entire drive system of an electric vehicle. However, some cooling modules may have limited thermal management capabilities.

[0005] This disclosure aims to overcome one or more of the aforementioned challenges. Summary of the Invention

[0006] In some aspects, the technology described herein relates to a system comprising an inverter for converting direct current (DC) power from a battery into alternating current (AC) power to drive a motor, wherein the inverter comprises: a capacitor assembly including: a planar busbar including a first DC busbar and a second DC busbar; a capacitor on the same side of the first DC busbar and the second DC busbar, the capacitor including a first end cap extending in a direction substantially perpendicular to the longitudinal direction of the planar busbar; and a first connecting plate shaped to transfer heat from the first end cap of the capacitor and the first connecting plate to a first outer surface.

[0007] In some respects, the technology described herein relates to a system in which a first connecting plate extends beyond its electrical connection with a first end cap.

[0008] In some respects, the technology described herein relates to a system in which a first connecting plate includes: a first portion at a first end cap; and a second portion extending substantially perpendicularly to the first portion, wherein a capacitor is located between a planar busbar and the second portion of the first connecting plate.

[0009] In some respects, the technology described herein relates to a system in which a first connecting plate includes: a first portion at a first end cap; and a second portion extending substantially perpendicularly to the first portion, wherein the second portion of the first connecting plate is between a capacitor and a planar busbar.

[0010] In some respects, the technology described herein relates to a system in which a first connecting plate further includes: a first portion at a first end cap; a second portion extending substantially perpendicularly to the first portion; and a third portion extending substantially perpendicularly to the first portion, wherein a capacitor is located between the second and third portions.

[0011] In some respects, the technology described herein relates to a system in which a first connecting plate comprises copper.

[0012] In some respects, the technology described herein relates to a system in which the capacitor further includes: a second end cap extending in a direction substantially perpendicular to the longitudinal direction of the planar busbars, the second end cap being on the end of the capacitor opposite to the end of the first end cap.

[0013] In some respects, the technology described herein relates to a system that further includes: a second connecting plate disposed at a second end cap for connecting a capacitor to a second DC busbar, wherein the shape of the second connecting plate is designed to transfer heat from the second end cap of the capacitor and the second connecting plate to a second outer surface.

[0014] In some respects, the technology described herein relates to a system that further includes: a battery configured to supply DC power to an inverter; and a motor configured to receive AC power from the inverter to drive the motor, wherein the system is provided as a vehicle.

[0015] In some respects, the technology described herein relates to a system in which a first connecting plate includes four connection points for connecting the first connecting plate to a first end cap.

[0016] In some respects, the technology described herein relates to a system in which a first connection plate includes a first connector and a second connector, both of which are connected to a first DC busbar.

[0017] In some aspects, the technology described herein relates to a capacitor assembly comprising: a capacitor including a wound metallized polypropylene film containing a central axis, a first end cap at a first end of the wound metallized polypropylene film, and a second end cap at a second end of the wound metallized polypropylene film opposite to the first end; a first connecting plate on the first end cap, wherein the first connecting plate is excessively large for a rated current, thereby transferring heat away from the capacitor; and a second connecting plate on the second end cap, wherein the second connecting plate is excessively large for a rated current, thereby transferring heat away from the capacitor.

[0018] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate includes: a first portion at a first end cap; and a second portion extending substantially perpendicularly to the first portion and in contact with the capacitor.

[0019] In some respects, the technology described herein relates to a capacitor assembly, wherein the capacitor includes a first surface and a second surface opposite to the first surface, wherein the first surface of the capacitor connects a first end cap to a second end cap, and the second surface of the capacitor connects the first end cap to the second end cap.

[0020] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate includes: a first portion at a first end cap; and a second portion extending substantially perpendicularly relative to the first portion, the second portion contacting a first surface or a second surface of the capacitor.

[0021] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate includes: a first portion at a first end cap; a second portion extending substantially perpendicularly to the first portion and in contact with a first surface of the capacitor; and a third portion extending substantially perpendicularly to the first portion and in contact with a second surface of the capacitor.

[0022] In some aspects, the technology described herein relates to a capacitor assembly for a power converter chassis recess, the capacitor assembly comprising: a planar busbar including a first DC busbar and a second DC busbar; a capacitor on the same side of the first DC busbar and the second DC busbar, the capacitor comprising: a metallized polypropylene film wound around a central axis extending in a direction substantially parallel to the longitudinal direction of the planar busbar; a first end cap at a first end of the metallized polypropylene film; and a second end cap at a second end of the metallized polypropylene film opposite to the first end; a first connecting plate disposed at the first end cap to connect the capacitor to the first DC busbar; and a second connecting plate disposed at the second end cap to connect the capacitor to the second DC busbar, wherein the first connecting plate and the second connecting plate are shaped to transfer heat from the first end cap and the second end cap to the power converter chassis recess.

[0023] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate extends along the entire length of a first end cap.

[0024] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate is mechanically stamped to a first end cap.

[0025] In some respects, the technology described herein relates to a capacitor assembly in which a portion of a first connecting plate is located between the capacitor and a planar busbar.

[0026] In some aspects, the technology described herein relates to a system comprising an inverter for converting direct current (DC) power from a battery into alternating current (AC) power to drive a motor, wherein the inverter comprises: a capacitor assembly including: a planar busbar including a first DC busbar and a second DC busbar; a capacitor on the same side of the first DC busbar and the second DC busbar, the capacitor including a first end cap extending in a direction substantially perpendicular to the longitudinal direction of the planar busbar; and a first connecting plate disposed at the first end cap to connect the capacitor to the first DC busbar.

[0027] In some respects, the technology described herein relates to a system in which the inverter further includes a thin-walled insulator disposed at a first end cap.

[0028] In some respects, the technology described herein relates to a system in which a capacitor includes a second end cap that extends at the end of the capacitor opposite to the first end cap in a direction substantially perpendicular to the longitudinal direction of the planar busbar.

[0029] In some respects, the technology described herein relates to a system that further includes: a second connecting plate that connects a second end cap to a second DC busbar.

[0030] In some respects, the technology described herein relates to a system in which a planar busbar further includes an insulating layer between a first DC busbar and a second DC busbar.

[0031] In some respects, the technology described herein relates to a system in which a first connection plate includes a first connector and a second connector, both of which are connected to a first DC busbar.

[0032] In some respects, the technology described herein relates to a system in which a first connecting plate comprises copper.

[0033] In some respects, the technology described herein relates to a system in which a first connecting plate extends through an opening in a second DC busbar.

[0034] In some aspects, the technology described herein relates to a system that further includes: a second capacitor located on the same side of a first DC busbar and a second DC busbar, the second capacitor including a first end cap extending in a direction substantially perpendicular to the longitudinal direction of the planar busbar; and a second connecting plate disposed at the first end cap of the second capacitor to connect the second capacitor to the first DC busbar, wherein the second connecting plate and the connecting plate are aligned and extend substantially perpendicular to each other.

[0035] In some respects, the technology described herein relates to a system that further includes: a battery configured to supply DC power to an inverter; and a motor configured to receive AC power from the inverter to drive the motor, wherein the system is provided as a vehicle.

[0036] In some aspects, the technology described herein relates to a capacitor assembly comprising: a capacitor including a wound metallized polypropylene film comprising a central axis, a first end cap at a first end of the wound metallized polypropylene film, and a second end cap at a second end of the wound metallized polypropylene film opposite to the first end; a first connecting plate connected to the first end cap and extending substantially perpendicularly to the central axis along a first direction; and a second connecting plate connected to the second end cap and extending substantially perpendicularly to the central axis along the first direction.

[0037] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate includes a first tab and a second tab, the first tab and the second tab extending substantially perpendicularly to a central axis along a first direction.

[0038] In some respects, the technology described herein relates to a capacitor assembly in which a second connecting plate includes a first tab and a second tab, the first tab and the second tab extending substantially perpendicularly to a central axis along a first direction.

[0039] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate is press-fitted to a first end cap.

[0040] In some respects, the technology described herein relates to a capacitor assembly in which the first end cap is arc-sprayed zinc.

[0041] In some aspects, the technology described herein relates to a capacitor assembly for a chassis recess of a power converter, the capacitor assembly comprising: a planar busbar including a first DC busbar and a second DC busbar; a capacitor on the same side of the first DC busbar and the second DC busbar, the capacitor comprising: a metallized polypropylene film wound around a central axis extending in a direction substantially parallel to the longitudinal direction of the planar busbar; a first end cap at a first end of the metallized polypropylene film; and a second end cap at a second end of the metallized polypropylene film opposite to the first end; a first connecting plate disposed at the first end cap for connecting the capacitor to the first DC busbar; and a second connecting plate disposed at the second end cap for connecting the capacitor to the second DC busbar.

[0042] In some respects, the technology described herein relates to a capacitor assembly in which a first connecting plate and a second connecting plate are configured to transfer heat from a first end cap and a second end cap to a recess in the chassis of a power converter.

[0043] In some respects, the technology described herein relates to a capacitor assembly in which a first DC busbar includes an opening, and a second connecting plate extends through the opening in the first DC busbar to connect to a second DC busbar.

[0044] In some respects, the technology described herein relates to a capacitor assembly that further includes: a thin-walled insulator disposed at a first end cap; and an epoxy resin layer between the thin-walled insulator and the first end cap.

[0045] In some respects, the technology described herein relates to a capacitor assembly in which: the thin-walled insulator is a plastic material for high-voltage insulation, and an epoxy resin layer is configured to seal the capacitor assembly for environmental protection.

[0046] Further objects and advantages of the disclosed embodiments will be set forth in part in the description which follows, and will be apparent in part from the description, or may be learned by practice of the disclosed embodiments. The objects and advantages of the disclosed embodiments will be realized and achieved by means of the elements and combinations particularly pointed out in the appended claims.

[0047] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and do not limit the claimed disclosed embodiments. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments.

[0049] Figure 1 An exemplary system infrastructure for a vehicle including an inverter, according to one or more embodiments, is described.

[0050] Figure 2 A schematic diagram of the electrical power of a three-phase inverter module according to one or more embodiments is depicted.

[0051] Figure 3 An exploded view of an exemplary capacitor according to one or more embodiments is depicted.

[0052] Figure 4 An exemplary epoxy-free capacitor according to one or more embodiments is depicted.

[0053] Figure 5 An exemplary epoxy resin capacitor according to one or more embodiments is depicted.

[0054] Figure 6 A cross-sectional view of an exemplary capacitor according to one or more embodiments is depicted.

[0055] Figure 7 A cross-section of an inverter according to one or more embodiments is depicted.

[0056] Figure 8 A detailed cross-section of an inverter according to one or more embodiments is depicted.

[0057] Figure 9 Side and front views of a capacitor assembly according to one or more embodiments are depicted.

[0058] Figure 10A A front view of a capacitor assembly with an L-shaped connecting plate according to one or more embodiments is depicted.

[0059] Figure 10B A side view of a capacitor assembly with an L-shaped connecting plate according to one or more embodiments is depicted.

[0060] Figure 11A A front view of a capacitor assembly with a T-shaped connecting plate according to one or more embodiments is depicted.

[0061] Figure 11B A side view of a capacitor assembly with a T-shaped connecting plate according to one or more embodiments is depicted.

[0062] Figure 12A A front view of a capacitor assembly with a C-shaped connecting plate according to one or more embodiments is depicted.

[0063] Figure 12B A side view of a capacitor assembly with a C-shaped connecting plate according to one or more embodiments is depicted. Detailed Implementation

[0064] Both the foregoing general description and the following detailed description are exemplary and interpretive only, and do not limit the claimed features. As used herein, the terms “comprises,” “comprising,” “has,” “having,” “includes,” “including,” or other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus. In this disclosure, unless otherwise stated, relative terms (such as, for example, “about,” “substantially,” and “approximately”) are used to indicate possible ±10% variation in the stated values. In this disclosure, unless otherwise stated, any numerical value may include possible ±10% variation in the stated values.

[0065] The terminology used below may be interpreted in its broadest and most reasonable manner, although it is used in conjunction with a detailed description of certain specific instances of this disclosure. In fact, certain terms may even be emphasized below; however, any term intended to be interpreted in any constrained manner will be explicitly and specifically defined as such in this Detailed Description section. For example, in the context of this disclosure, a switching device may be described as a switching element or device, but may refer to any device used to control the flow of power in a circuit. For example, a switching element may be, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated-gate bipolar transistor (IGBT), or a relay, or any combination thereof, but is not limited thereto.

[0066] The various embodiments of this disclosure generally relate to a capacitor, and more particularly, to a system for thermal management of a capacitor for an inverter in an electric vehicle.

[0067] Inverters (such as those used to drive motors in electric vehicles) are responsible for converting high-voltage direct current (“HVDC”) into alternating current (“AC”) to drive the motor. An inverter may include a power module and a corresponding cooling module assembly configured to cool the power module. The power module may include one or more silicon carbide (“SiC”) based power switches, which provide the relatively high power density and efficiency required to extend battery range and performance. The power module may contain circuitry and components configured to convert DC current from the electric vehicle battery into AC current, which can be utilized within the electric motor driving the propulsion system. A heat sink (e.g., the inverter chassis) can receive heat generated during capacitor operation, thereby cooling the capacitor. A laminated HVDC + / - busbar with internal insulation can reduce the equivalent series inductance (“ESL”) between the electric vehicle's battery and motor.

[0068] Inverter systems can operate under high ambient temperatures. The performance, assembly process, time, and reliability of the inverter system's power modules can depend on the built-in coolant structure. Heat sinks in inverter systems can improve performance and reliability.

[0069] Electric vehicles (“EVs”) and hybrid electric vehicles (“HEVs”) may include inverters with capacitors (e.g., large-capacity DC capacitors) to provide electrical noise filtering (or adequate filtering). Power from the inverter used to drive the electric motor (e.g., an electric motor) may generate significant heat in the large-capacity DC capacitor, which can be managed to prevent (or reduce) thermal overload and permanent damage (or failure) to the large-capacity DC capacitor. In some systems, the internal construction of the large-capacity DC capacitor may include connecting wound capacitor elements to circuitry. Some systems may include cooling of the main electrode plates to which the capacitor elements can be attached. Some systems may provide a cooling surface by placing the large-capacity DC capacitor in a vertically stacked assembly with cooling channels.

[0070] In electric vehicle technology, driving range is a key metric and market driver for new EVs, and it depends on the overall system efficiency of the EV. Some EV systems may place metallized polypropylene capacitors (e.g., with a maximum operating temperature of 105°C) between high-voltage (HV) and / or high-current electrode plates (HV+ / HV-), which may limit the system's minimum equivalent series inductance (ESL) and high-current capability. Such a large-capacity capacitor design in the DC link (e.g., a "sandwich design" or "sandwich structure") may also result in oversized, expensive electrical components to prevent capacitor thermal overload, potentially increasing unnecessary mass and / or cost, and possibly reducing vehicle efficiency.

[0071] Compared to some designs (such as the "sandwich design"), stacked busbar designs offer advantages such as low ESL and high DC capacity. For example, Figure 9 The stacked busbar design described herein may include placing the end caps of capacitor elements (e.g., with one or more HV- end caps and one or more HV+ end caps) at a 90° angle to the plane of the electrode plate busbar. The stacked busbar design may include electrical connections from the HV+ and HV- electrode plates to the end caps of the capacitor elements (e.g., one or more HV- end caps and one or more HV+ end caps). However, the stacked busbar design may result in heat from the DC current flowing through the electrode plates being superimposed with heat from the AC current flowing within the elements, without an efficient path for heat transfer from the capacitor elements.

[0072] In some systems, large-capacity capacitors may include basic electrical connections to the elements (e.g., for welding), but do not utilize the metal surface area created by the arc-sprayed zinc end caps or electrical connection terminals on the sides of the capacitor elements for heat transfer along the more thermally efficient axis.

[0073] Some systems may face thermal overload issues with capacitor elements due to hot spots within the capacitor cells connected above and / or below the electrode plates. This challenge can be addressed (or resolved) by modifying the capacitor cell package to maximize (or improve) heat transfer outward from the element center through the surfaces of the end caps and connecting plates, thereby utilizing improved (or better) thermal conductivity. Accordingly, in one or more embodiments, the capacitor elements are designed to use (or are configured to use) the surfaces of the arc-sprayed zinc end caps and connecting plates of each capacitor element to improve heat flow through the side end caps of each cell.

[0074] In some systems, capacitor elements may include capacitors commercially sold as finished parts, comprising packages intentionally designed for mechanical construction and including thick-walled plastic housings and basic electrical connections. Such designs do not utilize the required metal surface areas (e.g., zinc end caps and connecting plates) to intentionally transfer heat through the most efficient axis.

[0075] In some systems, alternating current (AC current) generated during the switching of the power supply can produce heat within the capacitor element. The AC current flows through the metallized pattern of the capacitor element, generating heat within it. Due to heat transfer, the hottest spot from the AC current is located at the center of the capacitor element. Alternatively, the capacitor element can be heated by direct current (DC current) flowing through the electrode plates adjacent to the capacitor element. The heat within the capacitor element (from the AC current) and the heat from the adjacent capacitor element (from the DC current) can potentially combine, and both can contribute to hot spots within the capacitor elements of the assembly.

[0076] The presence of hot spots within a capacitor element can reduce its lifespan and reliability. Redistributing heat to reduce hot spots can prevent (or reduce) component overload, thus providing thermal overload protection (or adequate protection). Some systems may include commercially available capacitors that include basic electrical connections to the capacitor element (e.g., for soldering), but do not utilize the required electrical connection terminals of the arc-sprayed end caps attached to the capacitor for heat distribution and transfer to reduce hot spots.

[0077] Some systems may face thermal overload issues with capacitor elements due to hot spots within the capacitor cells connected above and / or below the electrode plates. This challenge can be addressed (or resolved) by modifying the shape of the electrical connection terminals to maximize (or improve) heat transfer from the center of the element outward through the end caps and the surface of the connecting plates.

[0078] To improve system efficiency and reduce cost, the HV+ / HV- electrode plates can be positioned on top of each other (or directly on top) (separated by HV insulation). This arrangement may require capacitor elements to be positioned above or below a pair of electrode plates. To achieve an inverter with the smallest overall profile, allowing for packaging in more vehicle applications, the capacitor elements can be oriented at a 90-degree angle (e.g., the end caps of the capacitor elements change from a vertical to a horizontal position).

[0079] In one or more embodiments, the capacitor element may be arranged in a horizontal orientation, employing a low equivalent series inductance (ESL) and / or a small profile design, with end caps located on the same side of the HV+ and HV- electrode plates (e.g., both end caps are below them). In one or more embodiments, the capacitor element design may utilize manufacturing processes in the basic construction of the capacitor element, and make the thermal conductivity of the capacitor element between the required end caps (e.g., one or more HV- end caps and one or more HV+ end caps) and / or terminals better (or improved) than across the capacitor element body. For example, the thermal conductivity may be improved by approximately six times (e.g., approximately 6x ratio).

[0080] In one or more embodiments, the capacitor cell may use an improved thermal interface while maintaining the required HV insulation. In one or more embodiments, stacking of the individual layers may be used (or configured to use) to provide the required protection and improved heat transfer through the skeleton axis (e.g., zinc end caps and terminal connections), thereby improving thermal performance.

[0081] One or more embodiments may include a capacitor element having improved (e.g., about 6x ratio) thermal conductivity between end caps (compared to a wound polypropylene film body through the capacitor element), and may provide an improved thermal interface between the end caps of the capacitor element and a cooling surface. In one or more embodiments, the plastic walls are intended for HV insulation, and the epoxy resin within the capacitor cell is intended for environmental sealing and physical attachment. In one or more embodiments, because thermoplastics and epoxy resins have relatively poor thermal conductivity, it is intentional to make the walls of the plastic and epoxy resin fillers as thin as possible to allow for improved heat transfer while providing the desired HV insulation, environmental protection, and mechanical stability.

[0082] In one or more embodiments, a key advantage of the capacitor cell is its ability to intentionally transfer heat along the axis of the desired, most thermally conductive capacitor element. In one or more embodiments, the thin-walled HV insulation of the capacitor cell allows the use of highly conductive materials (e.g., aluminum, thermally conductive adhesives / components, etc.) as part of the thermal interface of the capacitor cell to meet thermal performance requirements.

[0083] In one or more embodiments, the HV insulation and internal environment sealing of the capacitor cell provide the necessary protection to allow pre-qualification of the capacitor cell sub-components, thereby reducing the risk, cost, machine tooling installation, and testing of new inverter designs. One or more embodiments may include a design that intentionally uses (or may be configured to intentionally use) the shape of the desired electrical connection terminals of the arc-sprayed zinc end caps attached to each capacitor element to redistribute and transfer heat, thereby reducing hot spots within the capacitor element. In one or more embodiments, the shape of the electrical connection terminals may be designed to redistribute and transfer heat from the capacitor element via a skeleton axis for heat transfer (e.g., zinc end cap and terminal connection), thereby improving thermal performance.

[0084] One or more embodiments may include a capacitor element designed to improve (e.g., by about 6x ratio) the thermal conductivity between end caps (e.g., compared to the wound polypropylene film body of the capacitor element), providing a heat distribution path within the capacitor element via thermal interfaces (e.g., between the end caps of the capacitor element) and cooling surfaces. In one or more embodiments, a key advantage of this design is the intentional redistribution of heat within the center of the capacitor element (e.g., from AC) using the desired shape of the capacitor's electrical connection terminals, thereby reducing hot spots in the MPP film, improving capacitor reliability, and eliminating (or reducing) the need for excessively large components to protect the capacitor from thermal overload. In one or more embodiments, the shape of the electrical connection terminals may be used (or configured to) intentionally transfer heat from internal hot spots along the axis of the desired and thermally most thermally conductive capacitor element (e.g., by about 6x ratio between the surfaces of the arc-sprayed zinc end caps).

[0085] Figure 1 Exemplary system infrastructure for a vehicle including a combined inverter and converter, according to one or more embodiments, is depicted. Alternatively, the inverter may be an inverter without a converter. Within the context of this disclosure, both an inverter without a converter and a combined inverter and converter can be referred to as an inverter. This disclosure provides an inverter as an exemplary embodiment, but this disclosure is not limited to inverters, and the description herein is applicable to any power converter or other electrical system including capacitors. Figure 1 As depicted, the electric vehicle 100 may include an inverter 110, a motor 190, and a battery 195. The inverter 110 may include components for receiving electrical power from an external source and outputting electrical power to charge the battery 195 of the electric vehicle 100. For example, the inverter 110 may convert DC power from the battery 195 in the electric vehicle 100 into AC power to drive the motor 190 of the electric vehicle 100 (e.g., to rotate it), but embodiments are not limited thereto. For example, the inverter 110 may be bidirectional and (e.g., during regenerative braking) convert DC power to AC power or vice versa. The inverter 110 may be a three-phase inverter, a single-phase inverter, or a multi-phase inverter.

[0086] Figure 2 A schematic diagram of the electrical power of a three-phase inverter module according to one or more embodiments is depicted. Figure 1 and Figure 2 As depicted, inverter 110 can be connected to battery 195 and motor 190. Battery 195 can be any power supply device, and motor 190 can be any load. Inverter 110 may include a first three-phase switch group 210 and a second three-phase switch group 220. The first phase U may be associated with ΦA, including switches Q1 and Q4; the second phase V may be associated with ΦB, including switches Q3 and Q6; and the third phase W may be associated with ΦC, including switches Q5 and Q2, as shown. Figure 2 As shown. The first three-phase switch group 210 may include a first phase switch Q1, a second phase switch Q3, and a third phase switch Q5. The second three-phase switch group 220 may include a first phase switch Q4, a second phase switch Q6, and a third phase switch Q2. Switches Q1 to Q6 may be metal-oxide-semiconductor field-effect transistors (MOSFETs), for example, but not limited to.

[0087] The first three-phase switch group 210 and the second three-phase switch group 220 can be driven by PWM signals generated by one or more controllers to convert DC power delivered via the input terminal group 285 at capacitor 230 into three-phase AC power at the outputs U, V, and W to the motor 190 via the output terminal group 295. Additionally, although Figure 1 and Figure 2 A three-phase inverter is shown, but this disclosure is not limited thereto and may include single-phase or multi-phase inverters.

[0088] Figure 3 An exploded view of an exemplary capacitor 300 according to one or more embodiments is depicted. The capacitor 300 may be... Figure 1 and Figure 2 The inverter 110 described herein includes components such as capacitor 230. Capacitor 300 may include capacitor element 302, first connecting plate 321, second connecting plate 322, epoxy resin 304, and pad 306. Capacitor 300 may be configured to smooth the flow of the inverter (e.g., ...). Figure 1 The inverter 110 depicted receives voltage fluctuations and noise from the DC input. The capacitor 300 can be configured to temporarily store and release energy, filter ripple / high-frequency noise, and maintain voltage levels when the inverter 110 supplies power.

[0089] The capacitor 300 may include a capacitor element 302. The capacitor element 302 may include a wound metallized polypropylene film 330, a first end cap 311 at a first end of the wound metallized polypropylene film 330, and a second end cap 312 at a second end of the wound metallized polypropylene film 330 (opposite to the first end). The first end cap 311 and the second end cap 312 may be arc-sprayed zinc applied to the wound metallized polypropylene film 330.

[0090] Capacitor 300 may include a first connecting plate 321 and a second connecting plate 322. For example, both the first connecting plate 321 and the second connecting plate 322 may be electrical conductors, such as copper. In some instances, the first connecting plate 321 and the second connecting plate 322 may be made entirely of copper. Both the first connecting plate 321 and the second connecting plate 322 may be configured to transfer heat to the outer surface of capacitor 300 and electrically connect capacitor 300 to one or more busbars (see [link to relevant documentation]). Figure 7 The first connecting plate 321 provides a high-voltage positive terminal (“HV+”) connection to the first DC bus (e.g., the HV+ electrode plate). The second connecting plate 322 provides a high-voltage negative terminal (“HV-”) connection to the second DC bus (e.g., the HV- electrode plate). The first connecting plate 321 can be coupled to the first end cap 311. The second connecting plate 322 can be coupled to the second end cap 312.

[0091] The capacitor 300 may include epoxy resin 304 configured to surround the capacitor element 302. Epoxy resin 304 may be a thermal adhesive configured to protect the capacitor element 302. Epoxy resin 304 may be contained within a pad 306. Pad 306 may be plastic and may be configured to accommodate the capacitor element 302 and epoxy resin 304. Pad 306 may be a thin wall extending around the capacitor element 302. For example, pad 306 may have a thickness of approximately 0.5 mm to approximately 1.5 mm.

[0092] Figure 4 An exemplary epoxy-free capacitor (e.g., capacitor 300) according to one or more embodiments is depicted. Figure 4 The capacitor 300 before the addition of epoxy resin 304 is depicted to show details of the connection between the first connecting plate 321 and the first end cap 311 of the capacitor element 302. The connection between the second connecting plate 322 and the second end cap 312 can be similar. The first connecting plate 321 and the second connecting plate 322 can be aligned on the capacitor element 302 and can extend away from the capacitor element 302 in substantially similar directions. Figure 4 Pad 306 is depicted as transparent to illustrate the arrangement of capacitor element 302 within pad 306.

[0093] Figure 5 An exemplary capacitor (e.g., capacitor 300) according to one or more embodiments is depicted. Epoxy resin 304 may be added to a pad 306 on the capacitor element 302. Figure 5 As depicted, the first connecting plate 321 can extend outward from the epoxy resin 304 as a tab (e.g., two tabs). Further, the second connecting plate 322 can extend outward from the epoxy resin 304 as a tab (e.g., two tabs). The tabs of the first connecting plate 321 and the second connecting plate 322 can be respectively connected to a busbar.

[0094] Figure 6 A cross-sectional view of an exemplary capacitor (e.g., capacitor 300) according to one or more embodiments is depicted. Figure 6 Depicting in Figure 5 The image depicts a cross-sectional view of a capacitor 300 between the contacts of the first connecting plate 321 and the second connecting plate 322. A wound metallized polypropylene film 330 may be a core component of the capacitor 300. The wound metallized polypropylene film 330 may include an aluminum pattern within the film. This pattern may be a filament of a metal film, which acts as an electrode of the capacitor 300. The pattern and thickness of the wound metallized polypropylene film 330 determine the capacitance, rated voltage, and performance of the capacitor 300.

[0095] The first connecting plate 321 and the second connecting plate 322 can serve as electrical terminals or electrodes of the capacitor 300. The shapes of the first connecting plate 321 and the second connecting plate 322 can be designed to transfer heat from the respective first end cap 311 and second end cap 312 to the outer surfaces. For example, the surface areas of the first connecting plate 321 and the second connecting plate 322 can accommodate corresponding current overloads. The capacitor 300 may include epoxy resin 304 in a pad 306 to cover the capacitor element 302, the first connecting plate 321, and the second connecting plate 322.

[0096] Figure 7 A cross-section of an inverter 700 according to one or more embodiments is depicted. For example, inverter 700 may correspond to inverter 110. Inverter 700 may include capacitor 300 (e.g., one or more capacitors, such as three capacitors) and chassis 740. Figure 4 similar, Figure 7 The capacitor 300 before the addition of epoxy resin 304 is depicted to show the internal components and connections of the capacitor 300.

[0097] The chassis 740 may comprise aluminum alloy, copper, or other suitable thermally conductive material. For example, the chassis 740 may be cast aluminum. The chassis 740 may serve as a heat sink for the capacitor 300. The chassis 740 may comprise one or more walls (e.g., four walls, or six walls) extending from the base plate 745 of the chassis 740. For example, first wall 741, second wall 742, third wall 743, and fourth wall 744 may extend from the base plate 745 of the chassis 740. Each of the first wall 741, second wall 742, third wall 743, and fourth wall 744 may comprise a surface (e.g., one surface, or two surfaces) configured to receive heat from the respective capacitor 300. The one or more walls (e.g., first wall 741, second wall 742, third wall 743, and fourth wall 744) may be stacked parallel to each other along the base plate 745 of the chassis 740. For example, the one or more walls may have a height of approximately 2 cm and a thickness of approximately 2 mm. One or more walls may have a height that is a portion of the height of the respective received capacitor (e.g., capacitor 300). For example, first wall 741 and fourth wall 744 may extend to a height greater than second wall 742 and third wall 743. In some instances, the width (thickness) of one or more walls may decrease as the walls extend away from the base plate 745 of the chassis 740. One or more walls may extend to a length approaching the length of the respective capacitor 300.

[0098] The walls of the chassis (e.g., first wall 741, second wall 742, third wall 743, and fourth wall 744) may be configured to receive the capacitor 300. For example, the first wall 741 and second wall 742 may form recesses that can receive the capacitor 300. A thermal interface material (TIM) 770 may be located between the capacitor 300 and the corresponding first wall 741, second wall 742, and base plate 745 of the chassis. For example, the TIM 770 may include epoxy resin, silicone, or other elastomer products. For example, the TIM 770 may be provided as a dielectric pad, heat sink, thermally conductive compound, thermally conductive gel (e.g., dispensable gel), thermally conductive tape, phase change material, spacer pad, thermal grease, or alternative thermally conductive material. The TIM 770 may be configured to transfer heat from the capacitor 300 to the chassis 740.

[0099] Inverter 700 may include a planar busbar 750. The planar busbar 750 may include a first DC busbar 751 overlapping a second DC busbar 752, wherein an insulating layer 753 exists between the first DC busbar 751 and the second DC busbar 752. The insulating layer 753 may be a high-voltage insulator, such as ceramic, glass, silicone rubber, epoxy resin, or polymer. The first DC busbar 751 may be an HV+ busbar electrode plate. For example, the first DC busbar 751 may include copper, aluminum, brass, silver, tungsten, nickel-plated copper, copper alloy composites, conductive polymers, or graphite. The second DC busbar 752 may be an HV- busbar electrode plate. For example, the second DC busbar 752 may include copper, aluminum, brass, silver, tungsten, nickel-plated copper, copper alloy composites, conductive polymers, or graphite. For example, both the first DC busbar 751 and the second DC busbar 752 may include copper. The first DC bus 751 and the second DC bus 752 can be aligned in a stacked position and located on a single side of the capacitor 300. The planar bus 750 can be connected to the capacitor 300 (e.g., one or more capacitors, such as three capacitors). The planar bus 750 can be configured to distribute power in the inverter 700.

[0100] Figure 8A detailed cross-section of an inverter 700 according to one or more embodiments is depicted. A first connection plate 321 of capacitor 300 may extend outward as a tab (e.g., one tab, e.g., two tabs) and be coupled to a first DC bus 751 at a connection point 761 (e.g., one connection point, e.g., two connection points). This connection point 761 may form an HV+ connection between capacitor 300 and the planar bus 750. A second connection plate 322 of capacitor 300 may extend outward as a tab (e.g., one tab, e.g., two tabs) and be coupled to a second DC bus 752 at a connection point 762 (e.g., one connection point, e.g., two connection points). This connection point 762 may form an HV- connection between capacitor 300 and the planar bus 750. The first DC bus 751 may include a connection point 761 (e.g., one connection point, e.g., two connection points) for each capacitor 300 coupled to the first DC bus 751. The second DC busbar 752 may include connection points 762 (e.g., one connection point, e.g., two connection points) for each capacitor 300 coupled to the second DC busbar 752. Connection points 761 and 762 can electrically connect the capacitor 300 to the planar busbar 750.

[0101] Capacitor 300 may be located on the same side of the first DC busbar 751 and the second DC busbar 752. Corresponding end caps (e.g., first end cap 311 and second end cap 312) may extend in a direction substantially perpendicular to the longitudinal direction of the planar busbar 750. First end cap 311 and second end cap 312 may extend in directions opposite to each other. Second end cap 312 may be located at the end of capacitor 300 opposite to first end cap 311.

[0102] Figure 9 Side and front views of a capacitor element and busbar according to one or more embodiments are depicted. View 900 depicts a cross-section of a wound metallized polypropylene film 330, a first end cap 311, a second end cap 312, and corresponding connections to a first connecting plate 321 and a second connecting plate 322. View 900 depicts how the first connecting plate 321 may extend outward toward a first DC busbar 751. The first connecting plate 321 may extend through an opening in the second DC busbar 752 and be coupled to the first DC busbar 751 at connection point 761. The second connecting plate 322 may extend and be coupled to the second DC busbar 752 at connection point 762. The second connecting plate 322 may extend through an opening in the first DC busbar 751. The wound metallized polypropylene film 330 may be wound about a central axis 910.

[0103] Views 901 and 902 depict corresponding side views of the HV connection between the respective connecting plates (e.g., first connecting plate 321 and second connecting plate 322) and the respective busbar plates (e.g., first DC busbar 751 and second DC busbar 752). Views 901 and 902 depict views at 90 degrees and 270 degrees relative to view 900 when the capacitor element is rotated along the centerline axis 910.

[0104] View 901 depicts an HV+ connection at connection point 761 between the first connection plate 321 and the first DC busbar 751. In some instances, the first connection plate 321 may include two separate tabs, both connected to the first DC busbar 751. View 902 depicts an HV- connection at connection point 762 between the second connection plate 322 and the second DC busbar 752. In some instances, the second connection plate 322 may include two separate tabs, both connected to the first DC busbar 751.

[0105] Figure 10A A front view of a capacitor assembly with an L-shaped connecting plate 1021 according to one or more embodiments is depicted. For example, the L-shaped connecting plate 1021 may be the exemplary first connecting plate 321 described above. The capacitor element 302 may include an L-shaped connecting plate 1022, which may be an exemplary second connecting plate 322.

[0106] The L-shaped connecting plate 1021 may include a first portion 1091, which includes a first end 1095 and a second end 1096 opposite to the first end 1095. The first portion 1091 may receive heat from the first end cap 311 and extends along the entire length of the first end cap 311. The L-shaped connecting plate 1021 may include a second portion 1092, which extends perpendicularly to the first portion 1091 at the second end 1096. The second portion 1092 may receive heat from the bottom surface 314 of the capacitor element 302. The capacitor element 302 may be located between a planar busbar (e.g., a first DC busbar 751 and a second DC busbar 752) and the second portion 1092.

[0107] Figure 10B A side view of a capacitor assembly with an L-shaped connecting plate 1021 according to one or more embodiments is depicted. Figure 10BThe diagram depicts how the L-shaped connecting plate 1021 can be coupled to the first end cap 311 at connection point 1080 (e.g., one connection point on each end cap; e.g., one or more connection points on each end cap for reliability; e.g., four connection points on each end cap to distribute heat across the surface of the end cap via the surface of the connecting plate rather than the surface of the end cap). Connection point 1080 can be solder, weld point, mechanical fastener (e.g., bolt, clamp, or lug), or press-fitted between the L-shaped connecting plate 1021 and the first end cap 311.

[0108] Figure 11A A front view of a capacitor assembly with a T-shaped connecting plate 1121 according to one or more embodiments is depicted. For example, the T-shaped connecting plate 1121 may be the exemplary first connecting plate 321 described above. The capacitor element 302 may include the T-shaped connecting plate 1122, which may be the exemplary second connecting plate 322.

[0109] The T-shaped connecting plate 1121 may include a first portion 1191, which includes a first end 1195 and a second end 1196 opposite to the first end 1195. The first portion 1191 may receive heat from the first end cap 311 and extends along the entire length of the first end cap 311. The T-shaped connecting plate 1121 may include a second portion 1192, which extends perpendicularly relative to the first portion 1191 at a position 1197 between the first end 1195 and the second end 1196. The second portion 1192 may receive heat from the top surface 313 of the capacitor element 302. The second portion 1192 may be located between a planar busbar (e.g., a first DC busbar 751 and a second DC busbar 752) and the capacitor element 302.

[0110] Figure 11B A side view of a capacitor assembly with a T-shaped connecting plate 1121 according to one or more embodiments is depicted. Figure 11B The diagram illustrates how the T-shaped connecting plate 1121 can be coupled to the first end cap 311 at connection points 1180 (e.g., one connection point, one or more connection points, four connection points). Connection points 1180 can be solder, weld points, mechanical fasteners (e.g., bolts, clamps, or lugs), or press-fitted between the T-shaped connecting plate 1121 and the first end cap 311.

[0111] Figure 12A A front view of a capacitor assembly with a C-shaped connecting plate 1221 according to one or more embodiments is depicted. For example, the C-shaped connecting plate 1221 may be the exemplary first connecting plate 321 described above. The capacitor element 302 may include the C-shaped connecting plate 1222, which may be the exemplary second connecting plate 322.

[0112] The C-shaped connecting plate 1221 may include a first portion 1291, which includes a first end 1295 and a second end 1296 opposite to the first end 1295. The first portion 1291 may receive heat from the first end cap 311 and extends along the entire length of the first end cap 311. The C-shaped connecting plate 1221 may include a second portion 1292, which extends perpendicularly to the first portion 1291 at the second end 1296. The second portion 1292 may receive heat from the bottom surface 314 of the capacitor element 302. The C-shaped connecting plate 1221 may include a third portion 1293, which extends perpendicularly to the first portion 1291 at a position 1297 between the first end 1295 and the second end 1296. The third portion 1293 may receive heat from the top surface 313 of the capacitor element 302. The capacitor element 302 may be located between the second portion 1292 and the third portion 1293.

[0113] Figure 12B A side view of a capacitor assembly with a C-shaped connecting plate 1221 according to one or more embodiments is depicted. Figure 12B The diagram depicts how the C-shaped connecting plate 1221 can be coupled to the first end cap 311 at connection points 1280 (e.g., one connection point, one or more connection points, four connection points). Connection point 1280 can be solder, weld point, mechanical fastener (e.g., bolt, clamp, or lug), or press fit (e.g., mechanical stamping) between the C-shaped connecting plate 1221 and the first end cap 311.

[0114] In one or more embodiments, the capacitor element may be arranged in a horizontal orientation, employing a low equivalent series inductance (ESL) and / or a small profile design, with end caps located on the same side of the HV+ and HV- electrode plates (e.g., both end caps are below them). In one or more embodiments, the capacitor element design may utilize manufacturing processes in the basic construction of the capacitor element, and make the thermal conductivity of the capacitor element between the required end caps (e.g., one or more HV- end caps and one or more HV+ end caps) and / or terminals better (or improved) than across the capacitor element body. For example, the thermal conductivity may be improved by approximately six times (e.g., approximately 6x ratio).

[0115] In one or more embodiments, the capacitor cell may use an improved thermal interface while maintaining the required HV insulation. In one or more embodiments, stacking of the individual layers may be used (or configured to use) to provide the required protection and improved heat transfer through the skeleton axis (e.g., zinc end caps and terminal connections), thereby improving thermal performance.

[0116] One or more embodiments may include a capacitor element having improved (e.g., about 6x ratio) thermal conductivity between end caps (compared to a wound polypropylene film body through the capacitor element), providing an improved thermal interface between the end caps and cooling surfaces of the capacitor element. In one or more embodiments, the plastic walls are intended for HV insulation, and the epoxy resin within the capacitor cell is intended for environmental sealing and physical attachment. In one or more embodiments, because thermoplastics and epoxy resins have relatively poor thermal conductivity, it is intentional to make the walls of the plastic and epoxy resin fillers as thin as possible to allow for improved heat transfer while providing the desired HV insulation, environmental protection, and mechanical stability.

[0117] In one or more embodiments, a key advantage of the capacitor cell is its ability to intentionally transfer heat along the axis of the desired, most thermally conductive capacitor element. In one or more embodiments, the thin-walled HV insulation of the capacitor cell allows the use of highly conductive materials (e.g., aluminum, thermally conductive adhesives / components, etc.) as part of the thermal interface of the capacitor cell to meet thermal performance requirements. In one or more embodiments, the HV insulation and internal environmental sealing of the capacitor cell provide the necessary protection to allow for pre-qualification of the capacitor cell sub-components, thereby reducing the risk, cost, machine tooling, and testing of new inverter designs.

[0118] One or more embodiments may include a design that intentionally uses (or may be configured to intentionally use) the shape of the desired electrical connection terminals of the arc-sprayed zinc end caps attached to each capacitor element to redistribute and transfer heat, thereby reducing hot spots within the capacitor element. In one or more embodiments, the shape of the electrical connection terminals is intentionally designed to redistribute and transfer heat from the capacitor element via a skeleton axis for heat transfer (e.g., zinc end cap and terminal connection), thereby improving thermal performance.

[0119] One or more embodiments may include a capacitor element designed to improve (e.g., by about 6x ratio) the thermal conductivity between end caps (e.g., compared to the wound polypropylene film body of the capacitor element), providing a heat distribution path within the capacitor element via thermal interfaces (e.g., between the end caps of the capacitor element) and cooling surfaces. In one or more embodiments, a key advantage of this design is the intentional redistribution of heat within the center of the capacitor element (e.g., from AC) using the desired shape of the capacitor's electrical connection terminals, thereby reducing hot spots in the MPP film, improving capacitor reliability, and eliminating (or reducing) the need for excessively large components to protect the capacitor from thermal overload. In one or more embodiments, the shape of the electrical connection terminals may be used (or configured to) intentionally transfer heat from internal hot spots along the axis of the desired and thermally most thermally conductive capacitor element (e.g., by about 6x ratio between the surfaces of the arc-sprayed zinc end caps).

[0120] Other embodiments of this disclosure will be apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The specification and examples are intended to be illustrative only, and the true scope and spirit of the invention are indicated by the appended claims.

Claims

1. A system comprising an inverter for converting direct current (DC) power from a battery into alternating current (AC) power to drive a motor, wherein the inverter comprises: Capacitor assembly, the capacitor assembly comprising: A planar busbar, comprising a first DC busbar and a second DC busbar; A capacitor, located on the same side of the first DC busbar and the second DC busbar, the capacitor including a first end cap extending in a direction substantially perpendicular to the longitudinal direction of the planar busbar; and A first connecting plate, the shape of which is designed to transfer heat from the first end cap of the capacitor and the first connecting plate to a first outer surface.

2. The system of claim 1, wherein the first connecting plate extends beyond its electrical connection with the first end cap.

3. The system according to claim 1, wherein the first connecting plate comprises: The first portion at the first end cap; as well as A second portion extending substantially vertically relative to the first portion, wherein the capacitor is located between the planar busbar and the second portion of the first connecting plate.

4. The system according to claim 1, wherein the first connecting plate comprises: The first portion at the first end cap; as well as A second portion extending substantially vertically relative to the first portion, wherein the second portion of the first connecting plate is between the capacitor and the planar busbar.

5. The system of claim 4, wherein the first connecting plate further comprises: The first portion at the first end cap; The second part extends substantially perpendicularly to the first part; as well as A third portion extends substantially vertically relative to the first portion, wherein the capacitor is located between the second portion and the third portion.

6. The system of claim 1, wherein the first connecting plate comprises copper.

7. The system of claim 1, wherein the capacitor further comprises: A second end cap extends in a direction substantially perpendicular to the longitudinal direction of the planar busbar, and is located on the end of the capacitor opposite to the end of the first end cap.

8. The system of claim 7, wherein the system further comprises: A second connecting plate is disposed at the second end cap to connect the capacitor to the second DC busbar, wherein the shape of the second connecting plate is designed to transfer heat from the second end cap of the capacitor and the second connecting plate to the second outer surface.

9. The system according to claim 1, further comprising: The battery is configured to supply the DC power to the inverter; as well as The motor is configured to receive AC power from the inverter to drive the motor. The system is provided as a vehicle.

10. The system of claim 1, wherein the first connecting plate comprises four connection points for connecting the first connecting plate to the first end cap.

11. The system of claim 1, wherein the first connecting plate includes a first connector and a second connector, wherein both the first connector and the second connector are connected to the first DC busbar.

12. A capacitor assembly comprising: A capacitor comprising a wound metallized polypropylene film including a central axis, a first end cap at a first end of the wound metallized polypropylene film, and a second end cap at a second end of the wound metallized polypropylene film opposite to the first end. A first connecting plate on the first end cap, wherein the first connecting plate is used to transfer heat away from the capacitor when the rated current is too high; as well as A second connecting plate on the second end cap, wherein the second connecting plate is excessive for the rated current, thereby transferring heat away from the capacitor.

13. The capacitor assembly of claim 12, wherein the first connecting plate comprises: The first portion at the first end cap; as well as The second part extends substantially vertically relative to the first part and is in contact with the capacitor.

14. The capacitor assembly of claim 12, wherein the capacitor includes a first surface and a second surface opposite to the first surface, wherein the first surface of the capacitor connects the first end cap to the second end cap, and the second surface of the capacitor connects the first end cap to the second end cap.

15. The capacitor assembly of claim 14, wherein the first connecting plate comprises: The first portion at the first end cap; as well as The second portion extends substantially perpendicularly to the first portion and contacts either the first or second surface of the capacitor.

16. The capacitor assembly of claim 14, wherein the first connecting plate comprises: The first portion at the first end cap; A second portion that extends substantially vertically relative to the first portion and contacts the first surface of the capacitor; as well as A third portion that extends substantially vertically relative to the first portion and contacts the second surface of the capacitor.

17. A capacitor assembly for a recessed area in a power converter chassis, the capacitor assembly comprising: A planar busbar, comprising a first DC busbar and a second DC busbar; A capacitor, located on the same side of the first DC busbar and the second DC busbar, comprising: A metallized polypropylene film wound around a central axis that extends in a direction substantially parallel to the longitudinal direction of the planar generatrix. A first end cap on the first end of the metallized polypropylene film; and A second end cap on the second end of the metallized polypropylene film opposite to the first end; A first connecting plate, disposed at the first end cap, is used to connect the capacitor to the first DC busbar; and A second connecting plate, disposed at the second end cap, is used to connect the capacitor to the second DC busbar. The first connecting plate and the second connecting plate are designed to transfer heat from the first end cap and the second end cap to the recess in the chassis of the power converter.

18. The capacitor assembly of claim 17, wherein the first connecting plate extends along the entire length of the first end cap.

19. The capacitor assembly of claim 17, wherein the first connecting plate is mechanically stamped to the first end cap.

20. The capacitor assembly of claim 17, wherein a portion of the first connecting plate is located between the capacitor and the planar busbar.

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