Capacitor for an inverter of an electric vehicle and associated method

Abstract

An electric vehicle according to an exemplary aspect of the present disclosure particularly includes an electric motor electrically coupled to a battery pack via an inverter. Additionally, the inverter includes a capacitor having an internal cooling channel. A method is also disclosed.

Description

Technical Field

[0001] The present disclosure relates to capacitors for an inverter of an electric vehicle. Background Art

[0002] The desire to reduce automotive fuel consumption and emissions is well known. Accordingly, vehicles that reduce or completely eliminate dependence on internal combustion engines are being developed. Currently, electric vehicles are being developed for this purpose. Generally, electric vehicles differ from conventional motor vehicles in that they are selectively driven by one or more electric motors powered by one or more batteries. In contrast, conventional motor vehicles rely entirely on an internal combustion engine to drive the vehicle.

[0003] A high-voltage battery pack generally powers the electric motor and other electrical loads of an electric vehicle. The electric motor is typically coupled to the battery pack through an inverter. Known inverters include capacitors that smooth voltage variations. Summary of the Invention

[0004] An electric vehicle according to an exemplary aspect of the present disclosure particularly includes an electric motor electrically coupled to a battery pack through an inverter. Additionally, the inverter includes a capacitor having an internal cooling channel.

[0005] In a further non-limiting embodiment of the foregoing electric vehicle, the internal cooling channel is located inside the exterior of the capacitor.

[0006] In a further non-limiting embodiment of any of the foregoing electric vehicles, the capacitor includes a capacitor block located inside the internal cooling channel.

[0007] In a further non-limiting embodiment of any of the foregoing electric vehicles, the capacitor includes an inlet and an outlet, and the internal cooling channel is configured to direct fluid from the inlet to the outlet.

[0008] In a further non-limiting embodiment of any of the foregoing electric vehicles, the internal cooling channel has a width dimension and a height dimension. The height dimension is greater than the width.

[0009] In a further non-limiting embodiment of any of the foregoing electric vehicles, the electric vehicle includes a cooling fluid source fluidly connected to the inlet.

[0010] In a further non-limiting embodiment of any of the foregoing electric vehicles, the exterior of the capacitor includes a front, a rear, a first side, a second side, a top, and a bottom. Additionally, the inlet and the outlet are formed in the front.

[0011] In a further non-limiting embodiment of any of the foregoing electric vehicles, the front and the rear have increased dimensions relative to the first side and the second side.

[0012] In a further non - limiting embodiment of any of the foregoing electric vehicles, the internal cooling channel is concentric with the perimeter of the capacitor.

[0013] In a further non - limiting embodiment of any of the foregoing electric vehicles, the internal cooling channel includes a plurality of segments, and each segment is parallel to an adjacent one of the front, rear, first side, and second side.

[0014] In a further non - limiting embodiment of any of the foregoing electric vehicles, each of the plurality of segments is spaced from the exterior of the capacitor by an amount that is substantially equal to the thickness of the internal cooling channel.

[0015] In a further non - limiting embodiment of any of the foregoing electric vehicles, the amount is constant for substantially the entire capacitor.

[0016] In a further non - limiting embodiment of any of the foregoing electric vehicles, the capacitor includes a plurality of busbars.

[0017] A capacitor for an inverter of an electric vehicle according to an exemplary aspect of the present disclosure particularly includes an internal cooling channel.

[0018] In a further non - limiting embodiment of the foregoing capacitor, a capacitor block is located inside the internal cooling channel, and the internal cooling channel is located inside the exterior of the capacitor.

[0019] In a further non - limiting embodiment of any of the foregoing capacitors, the capacitor includes an inlet and an outlet. The internal cooling channel is configured to direct fluid from the inlet to the outlet.

[0020] In a further non - limiting embodiment of any of the foregoing capacitors, the exterior of the capacitor includes a front, a rear, a first side, a second side, a top, and a bottom. Additionally, the internal cooling channel includes a plurality of segments, and each segment is parallel to an adjacent one of the front, rear, first side, and second side.

[0021] A method according to an exemplary aspect of the present disclosure particularly includes cooling a capacitor by directing fluid through an internal cooling channel of a capacitor for an inverter of an electric vehicle.

[0022] In a further non - limiting embodiment of the foregoing method, the cooling step includes directing fluid through a plurality of segments of the internal cooling channel. Additionally, each of the plurality of segments extends in a direction that is substantially parallel to an adjacent surface of the exterior of the capacitor.

[0023] In a further non - limiting embodiment of any of the foregoing methods, each of the plurality of segments is spaced from an adjacent surface of the exterior of the capacitor by an amount that is substantially equal to the thickness of the internal cooling channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematically illustrates a powertrain of an electric vehicle.

[0025] Figure 2 is a perspective view of a capacitor.

[0026] Figure 3 is Figure 2 a cross-sectional view of the capacitor taken along line 3-3.

[0027] Figure 4 is Figure 3 a cross-sectional view of the capacitor taken along line 4-4. DETAILED DESCRIPTION

[0028] The present disclosure relates to a capacitor for an inverter of an electric vehicle. In one example, an electric vehicle includes a motor electrically coupled to a battery pack via an inverter, and the inverter includes a capacitor having an internal cooling channel. Providing an internal cooling channel for the capacitor allows for increased cooling, which increases the output power of the capacitor and, in turn, increases the power density of the inverter.

[0029] Figure 1 Schematically illustrates a powertrain 10 of an electric vehicle 12. Although described as a battery electric vehicle (BEV), it should be understood that the concepts described herein are not limited to BEVs and can be extended to other electric vehicles, including but not limited to plug-in hybrid electric vehicles (PHEVs). Thus, although not shown in this non-limiting embodiment, the electric vehicle 12 can be equipped with an internal combustion engine that can be used alone or in combination with other energy sources to propel the electric vehicle 12.

[0030] In a non-limiting embodiment, the electric vehicle 12 is a battery electric vehicle that is propelled only by electricity (such as via a motor 14) without any assistance from an internal combustion engine. The motor 14 is operable as an electric motor, a generator, or both. The motor 14 receives electrical power and provides a rotational output power. The motor 14 can be connected to a transmission 16 for adjusting the output torque and speed of the motor 14 at a predetermined gear ratio. The transmission 16 is connected to a set of drive wheels 18 via an output shaft 20. A high-voltage bus 22 electrically connects the motor 14 to the battery pack 24 via an inverter 26. The motor 14, the transmission 16, and the inverter 26 can be collectively referred to as a powertrain 28. It is known that the inverter 26 includes one or more capacitors, such as the capacitor described with respect to Figure 2 and Figure 3 described. It should be understood that the present disclosure is not limited to the capacitor for the inverter 26 and extends to capacitors used elsewhere in the vehicle 12.

[0031] The battery pack 24 is an exemplary electric vehicle battery. The battery pack 24 can be a high-voltage traction battery pack that includes a plurality of battery assemblies 25 (i.e., a battery array or a battery cell group) capable of outputting electrical power to operate the motor 14 of the electric vehicle 12 and / or other electrical loads. Other types of energy storage devices and / or output devices can also be used to power the electric vehicle 12. The energy storage device (e.g., a battery cell) of the battery pack 24 can be periodically charged. To this end, the energy storage device can be selectively coupled to a charging station, which in turn is connected to an external power source for receiving electrical power and distributing electrical power to the energy storage device.

[0032] Figure 1 The powertrain 10 shown is highly schematic and is not intended to limit the present disclosure. In this regard, it should be understood that certain aspects of the powertrain 10 are enlarged in the drawings for illustrative purposes only. Within the scope of the present disclosure, the powertrain 10 optionally or additionally employs a variety of additional components.

[0033] Figure 2 is a perspective view of an exemplary capacitor 30 according to the present disclosure. In one example, the capacitor 30 can be part of the inverter 26 and is used to smooth out variations in voltage. During use, the capacitor 30 generates a large amount of heat. The amount of ripple current that the capacitor 30 can handle is limited by the maximum allowable operating temperature of the capacitor 30. In the present disclosure, the capacitor 30 includes an internal cooling channel 32( Figure 3 ) that directs a fluid F within the capacitor 30 to thermally condition the capacitor. Specifically, the fluid F cools the capacitor 30, which allows for an increase in ripple current handling and, in turn, an increase in the power density of the inverter 26.

[0034] The capacitor 30 has an exterior 34 that has a generally rectangular prism shape. In this example, the exterior 34 includes a front face 36, a rear face 38, a first side 40, a second side 42, a top 44, and a bottom 46. The capacitor 30 has a length L 1 、width W 1 and height H 1 and the surfaces of the exterior 34 are oriented substantially at right angles. The length L 1 is substantially greater than the width W 1 and height H 1 , and in this example, it should be understood that the present disclosure is not limited to any particular external dimensions. Additionally, in this example, the capacitor 30 includes a bus bar 47 that protrudes from the top 44. The bus bar 47 is configured to electrically couple the capacitor 30 to various other components of the inverter 26.

[0035] The inlet 48 and the outlet 50 are formed through the exterior 34 and are configured to direct the fluid F into and out of the internal cooling channels 32. The inlet 48 and the outlet 50 may be formed through a common surface of the exterior 34. In this example, the inlet 48 and the outlet 50 are formed in the front face 36. It should be understood that the inlet 48 and the outlet 50 may be formed through other surfaces of the exterior 34. Referring to the outlet 50, the inlet 48 and the outlet 50 are substantially rectangular in shape, each having a width W 2 and a height H 2 . In one example, the height is H 2 greater than the width W 2 , but it should be understood that the present disclosure extends to other dimensions.

[0036] The inlet 48 is fluidly connected to a fluid source 52. As an example, the fluid source 52 may be the same fluid source that directs cooling fluid to other components of the inverter 26, such as a power supply board or a power module. Alternatively, the fluid source 52 may be a separate fluid source dedicated to the capacitor 30. The fluid source 52 may supply any type of known fluid F to the inlet 48. After flowing through the internal cooling channels 32, the fluid F absorbs heat from the capacitor 30 and returns to the fluid loop 54. The fluid loop 54 may be the same fluid loop used by other fluid-cooled components of the inverter 26.

[0037] Figure 3 is a cross-sectional view of the capacitor 30 taken along line 3-3 in Figure 2 . Figure 3 Illustrates a capacitor block 56 (shown in dashed lines) located inside the internal cooling channels 32. In the present disclosure, the term capacitor block refers to the various components known to be associated with a capacitor, such as capacitor cells, lead frames, etc. In one example, the capacitor block is an off-the-shelf capacitor. In one example, the capacitor 30 is a thin film capacitor and the capacitor block 56 includes components known to correspond to a thin film capacitor.

[0038] Generally, the internal cooling channels 32 and the exterior 34 of the capacitor are formed by overmolding the capacitor block 56. Overmolding is a process of adding material to an existing part or portion (e.g., the capacitor block 56) using a molding process. The result is an integrated component that includes one or more original components and additional material added through the overmolding process. While overmolding is considered herein, the present disclosure extends to other manufacturing techniques.

[0039] In combination with Figure 2 and Figure 3, the details of the internal cooling channel 32 will now be described. In this example, the internal cooling channel 32 is completely surrounded by the exterior 34. In particular, the internal cooling channel 32 is surrounded by overmolding of the capacitor block 56. Additionally, the internal cooling channel 32 is located inside the exterior 34 of the capacitor 30. In this way, the fluid F flowing through the internal cooling channel 32 flows relatively close to the capacitor block 56 and thus absorbs a relatively large amount of heat from the capacitor block 56.

[0040] In this example, the internal cooling channel 32 is relatively tall and thin. In particular, the internal cooling channel 32 has a height H that is substantially equal to the height H 2 of height H 3 ( Figure 4 ) and a width W that is less than the height H 3 of width W 3 . Further, in one example, the internal cooling channel 32 is spaced apart from the adjacent surface of the exterior 34 by an amount represented by a distance D that is substantially equal to the width W 3 of distance D 1 . The distance D 1 remains constant for substantially the entire internal cooling channel 32. The size and arrangement of the internal cooling channel 32 allow for sufficient flow of the fluid F (e.g., to effectively condition the capacitor) without providing an overly large capacitor.

[0041] In this example, the internal cooling channel 32 is composed of a plurality of interconnected segments. The segments are arranged such that the internal cooling channel 32 is symmetric about a centerline C that bisects the capacitor 30 in a direction perpendicular to the length L 1 . Additionally, the segments are substantially parallel to the adjacent surface of the exterior 34 such that the perimeters of the internal cooling channel 32 and the exterior 34 are concentric.

[0042] Starting near the inlet 48, the internal cooling channel 32 includes a first section 58 that extends from the inlet 48 to a point adjacent to the first side 40 of the capacitor 30. The first section 58 extends substantially parallel to the front face 36. Downstream of the first section 58, the internal cooling channel 32 includes a second section 60 that is arranged perpendicular to the first section 58 and extends parallel to the first side 40. A third section 62 is adjacent to the second section 60 and perpendicular to the second section 60. The third section 62 extends in a direction parallel to the rear face 38 and is configured to direct the fluid F substantially from the first side 40 of the capacitor 30 to the second side 42. Adjacent to the second side 42, the internal cooling channel 32 includes a fourth section 64 that is perpendicular to the third section 62 and extends parallel to the second side 42. Finally, the internal cooling channel 32 includes a fifth section 66 that is perpendicular to the fourth section 64 and is configured to direct the fluid F from the fourth section 64 to the outlet 50. As shown, each of the sections 58, 60, 62, 64, 66 is parallel to an adjacent one of the front face 36, rear face 38, first side 40, and second side 42. Although multiple sections are shown, it should be understood that the present disclosure extends to other arrangements of the internal cooling channel 32.

[0043] In use, the fluid F is directed through the internal cooling channel 32. The fluid F flows through each of the sections 58, 60, 62, 64, 66 from the inlet 48 and is discharged from the outlet 50. Generally as described above, the fluid F absorbs heat from the capacitor block 56, which thermally regulates the capacitor 30, allowing an increase in the ripple current handling without exceeding the maximum allowable operating temperature.

[0044] It should be understood that terms such as "front", "rear", "top", "side", "interior", etc. are relative to the normal orientation of the capacitor and are for explanatory purposes only and should not be considered limiting. Additionally, terms such as "generally", "about", and "substantially" are not intended to be unbounded terms and should be interpreted in a manner consistent with how those skilled in the art would interpret these terms.

[0045] Although different examples have specific components shown for illustration, embodiments of the present disclosure are not limited to those specific combinations. Some components or features from one example may be used in combination with features or components from another example.

[0046] Those of ordinary skill in the art will understand that the above embodiments are exemplary and not restrictive. That is, modifications to the present disclosure will fall within the scope of the claims. Accordingly, the appended claims should be studied to determine their true scope and content.

[0047] According to the present invention, there is provided an electric vehicle having an electric machine electrically coupled to a battery pack through an inverter, the inverter including a capacitor having an internal cooling channel.

[0048] According to an embodiment, an internal cooling channel is located inside the exterior of the capacitor.

[0049] According to an embodiment, the capacitor includes a capacitor block located inside the internal cooling channel.

[0050] According to an embodiment, the capacitor includes an inlet and an outlet, and the internal cooling channel is configured to direct fluid from the inlet to the outlet.

[0051] According to an embodiment, the internal cooling channel has a width dimension and a height dimension, and the height dimension is greater than the width.

[0052] According to an embodiment, the above invention is further characterized in that a cooling fluid source is fluidly connected to the inlet.

[0053] According to an embodiment, the exterior of the capacitor includes a front, a rear, a first side and a second side, a top and a bottom, and wherein the inlet and the outlet are formed in the front.

[0054] According to an embodiment, the front and the rear have increased dimensions relative to the first side and the second side.

[0055] According to an embodiment, the internal cooling channel is concentric with the perimeter of the capacitor.

[0056] According to an embodiment, the internal cooling channel includes a plurality of segments, and each of the segments is parallel to an adjacent one of the front, the rear, the first side and the second side.

[0057] According to an embodiment, each of the plurality of segments is spaced from the exterior of the capacitor by an amount that is substantially equal to the thickness of the internal cooling channel.

[0058] According to an embodiment, the amount is constant for substantially the entire capacitor.

[0059] According to an embodiment, the capacitor includes a plurality of bus bars.

[0060] According to the present invention, there is provided a capacitor for an inverter of an electric vehicle, which has an internal cooling channel.

[0061] According to an embodiment, the above invention is further characterized in that the capacitor block is located inside the internal cooling channel, and the internal cooling channel is located inside the exterior of the capacitor.

[0062] According to an embodiment, the above invention is further characterized in that the inlet and the outlet, and the internal cooling channel is configured to direct fluid from the inlet to the outlet.

[0063] According to an embodiment, the exterior of the capacitor includes a front, a rear, a first side and a second side, a top and a bottom, the internal cooling channel includes a plurality of segments, and each segment is parallel to an adjacent one of the front, the rear, the first side and the second side.

[0064] According to the present invention, there is provided a method having: cooling a capacitor by guiding a fluid through an internal cooling channel of a capacitor of an electric vehicle.

[0065] According to an embodiment, the above invention is further characterized in that the cooling step includes guiding the fluid through a plurality of segments of the internal cooling channel, each of the plurality of segments extending in a direction substantially parallel to an adjacent surface of the exterior of the capacitor.

[0066] According to an embodiment, the amount by which each of the plurality of segments is spaced apart from an adjacent surface of the exterior of the capacitor is substantially equal to the thickness of the internal cooling channel.

Claims

1. An electric vehicle, comprising: including: a motor electrically coupled to a battery pack through an inverter, the inverter including a capacitor having an internal cooling channel, wherein an exterior of the capacitor includes a front, a rear, a first side and a second side, a top and a bottom, the internal cooling channel includes a plurality of segments, and wherein each segment is parallel to and spaced from an adjacent one of the front, the rear, the first side and the second side by an amount substantially equal to a width of the internal cooling channel.

2. The electric vehicle according to claim 1, wherein the internal cooling channel is located inside the exterior of the capacitor.

3. The electric vehicle according to any one of the preceding claims, wherein the capacitor includes a capacitor block located inside the internal cooling channel.

4. The electric vehicle according to claim 1, wherein the capacitor includes an inlet and an outlet, and the internal cooling channel is configured to direct fluid from the inlet to the outlet.

5. The electric vehicle according to claim 1, wherein the internal cooling channel has a width dimension and a height dimension, and the height dimension is greater than the width dimension.

6. The electric vehicle according to claim 4, further comprising a cooling fluid source fluidly connected to the inlet.

7. The electric vehicle according to claim 4, wherein the inlet and the outlet are formed in the front.

8. The electric vehicle according to claim 7, wherein the front and the rear have an increased size relative to the first side and the second side.

9. The electric vehicle according to claim 1, wherein the internal cooling channel is concentric with a perimeter of the capacitor.

10. The electric vehicle according to claim 1, wherein the amount is constant for substantially the entirety of the capacitor.

11. A method for an electric vehicle, comprising: including: cooling a capacitor of an inverter for an electric vehicle by directing fluid through an internal cooling channel of the capacitor, wherein the cooling step includes directing fluid through a plurality of segments of the internal cooling channel, each of the plurality of segments extending in a direction substantially parallel to an adjacent surface of an exterior of the capacitor; wherein each of the plurality of segments is spaced from the adjacent surface of the exterior of the capacitor by an amount substantially equal to a width of the internal cooling channel.

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