GB2560338A

GB2560338A - Cooling plate

Info

Publication number: GB2560338A
Application number: GB1703651.8A
Authority: GB
Inventors: Tsonev Kaloyan; Smith Richard
Original assignee: Arrival Ltd
Current assignee: Arrival UK Ltd
Priority date: 2017-03-07
Filing date: 2017-03-07
Publication date: 2018-09-12
Anticipated expiration: 2037-03-07
Also published as: GB2560338B; GB201703651D0

Abstract

A cooling plate 40 comprising a recess 47 and a mounting surface 49 for an electronic power controller. The recess has a bottom surface 55 with inlet holes 58-60 and outlet holes 61-63 which are aligned with a plurality of switching transistors 8-10 of a power controller. The inlet and outlet holes may be in fluid communication with inner conduits 64 and 65 which extend to inlet 56 and outlet 57 respectively. The length of the path travelled by the fluid may be irrespective of the inlet and outlet hole used. The inlet and outlet holes may be arranged on opposite sides of the recess, preferably in a line adjacent to major sides of a rectangular recess. The cooling plate may comprise a thermally conductive material and may have a heat sink. An assembly of the cooling plate with a power controller is discussed. The power controller may have a plurality of switching transistors 8-10 on a backplate, which may have a pump and plurality of, preferably conical, protrusions. The protrusions may be arranged in columns and offset rows. A vehicle comprising the power controller assembly is disclosed.

Description

(54) Title of the Invention: Cooling plate

Abstract Title: Cooling plate for an electronic power controller (57) A cooling plate 40 comprising a recess 47 and a mounting surface 49 for an electronic power controller. The recess has a bottom surface 55 with inlet holes 58-60 and outlet holes 61-63 which are aligned with a plurality of switching transistors 8-10 of a power controller. The inlet and outlet holes may be in fluid communication with inner conduits 64 and 65 which extend to inlet 56 and outlet 57 respectively. The length of the path travelled by the fluid may be irrespective of the inlet and outlet hole used. The inlet and outlet holes may be arranged on opposite sides of the recess, preferably in a line adjacent to major sides of a rectangular recess. The cooling plate may comprise a thermally conductive material and may have a heat sink. An assembly of the cooling plate with a power controller is discussed. The power controller may have a plurality of switching transistors 8-10 on a backplate, which may have a pump and plurality of, preferably conical, protrusions. The protrusions may be arranged in columns and offset rows. A vehicle comprising the power controller assembly is disclosed.

FIG. 7 /9

2/9

3/9

4/9

17'

v.

ο

C:

CU

5/9

CO 00

Vco co o>

CM co

to N300 ·*6/9

LO

CD

DI

7/9 μ-

ο

St

9/9

Cooling Plate

Field

This disclosure relates to a cooling plate for an electronic power controller, particularly 5 but not exclusively a cooling plate for an electronic power controller for an electric, hybrid, or range-extended vehicle. This disclosure also relates to a cooling system for an electronic power control system, and to a vehicle having the cooling system and electronic power controller.

Background

Electric, hybrid and range-extended vehicles run on high power electricity that powers electric motors to drive the vehicle. The electric power, usually supplied from batteries, is passed through a power controller that generates the appropriate power supply for the electric motors. For example, the power controller may convert a DC power input from a battery into a 3-phase power output for the electric motor.

Due to the high power of such a system the power controller can generate significant excess heat that may be to the detriment of the function of the power control circuitry within the controller. Known cooling systems use water to cool power controllers, and this involves passing the water across a surface of the power controller so that heat is absorbed in the water and carried away. Water is provided to the cooling system via a water inlet and exits via a water outlet. However, known cooling systems can result in a temperature gradient across different parts of the power control circuitry because parts closer to the water inlet will be cooled to a greater extent than parts closer to the water outlet.

Summary

According to an aspect of the present invention, there is provided a cooling plate for a power controller, the power controller comprising a plurality of switching transistors;

wherein the cooling plate comprises a recess and a mounting surface adapted such that said power controller is attachable to the mounting surface to cover the recess and define a cooling fluid chamber, the recess comprising an opposing surface that faces said power controller when said power controller is attached to the mounting surface;

wherein the opposing surface of the recess comprises a plurality of cooling fluid inlet holes and a plurality of cooling fluid outlet holes, and wherein at least one cooling fluid inlet hole and at least one cooling fluid outlet hole is aligned with each of said plurality of switching transistors when said power controller is attached to the mounting surface.

The cooling plate may further comprise an inlet conduit that is in fluid communication with each cooling fluid inlet hole. The inlet conduit may extend to an inlet formed on a side of the cooling plate.

The cooling plate may further comprise an outlet conduit that is in fluid 10 communication with each cooling fluid outlet hole. The outlet conduit may extend to an outlet formed on a side of the cooling plate.

In some examples, the cooling plate further comprises an outlet conduit that is in fluid communication with each cooling fluid outlet hole, and the outlet conduit may extend to an outlet formed on the side of the cooling plate.

The inlet conduit and the outlet conduit may be configured such that the length of the path from the inlet to the outlet is the same via each cooling fluid inlet hole and cooling fluid outlet hole.

The opposing surface of the recess may comprise one cooling fluid inlet hole per switching transistor and one cooling fluid outlet hole per switching transistor.

The cooling fluid inlet hole and cooling fluid outlet hole associated with each switching 25 transistor may be disposed at opposing ends of said switching transistor.

Preferably, the cooling fluid inlet holes are arranged adjacent to a first side of the recess, and the cooling fluid outlet holes are arranged adjacent to a second side of the recess, the second side being opposite to the first side.

In some examples, the recess is rectangular and comprises first and second major sides and first and second minor sides, the first and second major sides being longer than the first and second minor sides, and wherein the switching transistors are arranged in a line formed between the first and second minor sides.

-3The cooling fluid outlet holes may be arranged in a line adjacent to the first major side of the recess, and the cooling fluid inlet holes maybe arranged in a line adjacent to the second major side of the recess.

Each cooling fluid inlet hole may be aligned with a cooling fluid outlet hole in a direction of the first and second minor sides of the recess.

The cooling plate may comprise a thermally conductive material.

The cooling plate may comprises a heat sink.

According to a further aspect of the present invention, there is also provided a power control assembly comprising:

a power controller having a plurality of switching transistors; and 15 a cooling plate as described above.

The power controller may comprise a backplate, and the plurality of switching transistors may be attached to the backplate, the backplate being attached to the mounting surface.

Preferably, the backplate comprises a plurality of protrusions that extend into the cooling fluid chamber towards the opposing surface. In some examples, the plurality of protrusions are conical. In some examples, the protrusions are arranged in columns and offset rows.

The power control assembly may further comprise a pump arranged to circulate cooling fluid through the cooling fluid chamber via the cooling fluid inlet holes and cooling fluid outlet holes.

The power controller preferably comprises three switching transistors.

According to another aspect of the present invention, there is also provided a vehicle comprising the power control assembly described above.

The vehicle may further comprise an electric motor arranged to provide a driving force for the vehicle.

-4The vehicle may be an electric, hybrid, or range-extended vehicle.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. l shows a schematic diagram of an electric drive system for a vehicle; io FIG. 2 shows an electronic power controller;

FIG. 3 shows a cooling plate according to the prior art;

FIG. 4 shows a cross-section of the cooling plate of FIG. 3 and the electronic power controller of FIG. 2, during use;

FIG. 5 shows the backplate of the electronic power controller of FIG. 2;

FIG. 6 shows an example cooling plate of the present invention;

FIG. 7 shows a top view of the example cooling plate of FIG. 6;

FIG. 8 shows a cross-section of the example cooling plate of FIG. 6 and FIG. 7; and, FIG. 9 shows a further example cooling plate of the present invention.

Detailed Description

FIG. 1 shows a schematic diagram of an electric drive system 1 for a vehicle 2. The electric drive system 1 includes a battery 3, a power controller 4, and an electric motor 5. The battery 3 provides DC current to the power controller 4. In this example, the electric motor 5 runs on three phase current, and the power controller 4 modulates the DC current into the three phase power output for driving the electric motor 5. The electric motor 5 is coupled to the drive mechanism 6 of the vehicle 2, for example a drive shaft or wheel, for driving the vehicle 2.

The power controller 4, illustrated in FIG. 2, comprises a backplate 7 and three switching transistors 8, 9,10 mounted to the backplate 7. The switching transistors 8, 9,10 include electrical terminals (not shown) for connecting wires that connect the power controller 4 to the battery 3 (see FIG. 1) and electric motor 5 (see FIG. 1). Each switching transistor 8, 9,10 is configured to generate an AC power output from a DC power input received from the battery 3 (see FIG. 1). Together, the three switching transistors 8, 9,10 provide 3 phase power.

-5As illustrated, the backplate 7 of the power controller is cuboid. In particular, the backplate 7 is planar, with a first major side 11, a second major side 12, a first minor side 13, and a second minor side 14, the major sides 11,12 being longer than the minor sides 13,14. The depth of the backplate 7 is significantly less than the it’s other dimensions. The switching transistors 8, 9,10 are mounted to a top surface 15 of the backplate 7.

In this example, the backplate 7 is cuboid, i.e. the first and second major sides 11,12 are 10 parallel to each other, the first and second minor sides 13,14 are parallel to each other, and the first and second major sides 11,12 are perpendicular to the first and second minor sides 13,14. As illustrated, the switching transistors 8, 9,10 are mounted to the top surface 15 of the backplate 7 in a line, with one switching transistor 10 at a first end of the backplate 7, adjacent the first minor side 13, one switching transistor 8 at a second end of the backplate 7, adjacent the second minor side 14, and the third switching transistor 9 disposed in between the other switching transistors 8,10.

In one example, the switching transistors 8, 9,10 are each an insulated-gate bipolar transistor (IGBT). In other examples the switching transistors 8, 9,10 may alternatively comprise a metal-oxide-semiconductor field-effect transistor (MOSFET). In other examples, the switching transistors 8, 9,10 may comprise Gallium Nitride based field effect transistors (GaN FET). The semi-conductors of the switching transistors 8, 9,10 maybe arranged in a multitude of combinations (both parallel and series connected) to provide the correct voltage and current magnitude required by the motor drive system.

Electric vehicles use high power systems to drive the electric motors. For example, the electric drive system may run on 2 kilowatts or more of DC power from the battery system to drive compressors and/or pumps to provide air and hydraulic services to the vehicle for braking and steering assistance. Generally much higher power levels are required for propulsion; for small passenger cars 3O-5OkW of electrical power is common. For commercial vehicles 50-iookW of electrical drive power is common, and for racing applications much higher powers are required from ioo-25okW, or above.

The power controller 4, in particular the switching transistors 8, 9,10, generate excess heat during operation. This excess heat may reduce the operating efficiency of the switching transistors 8, 9,10. In particular, the switching transistors 8, 9,10 may

-6include semi-conductors that perform less efficiently at elevated temperatures. In addition, operating temperature differences between the switching transistors 8, 9,10 of the power controller 4 may degrade performance. Therefore, it is desirable to cool the power controller 4 during operation, and to provide uniform temperature across the power controller 4.

The power controller 4 illustrated in FIG. 2 and described above maybe a part of a larger power control system. For example, additional power control electronics maybe included.

FIG. 3 and FIG. 4 illustrate a cooling system 20 for the power controller 4 described with reference to FIGS. 1 and 2. The cooling system 20 of FIG. 3 and FIG. 4 is a conventional arrangement for cooling the power controller 4, and is known in the prior art.

The cooling system 20 comprises a cooling plate 21 that is cuboidal and adapted such that the power controller 4 is attachable to the cooling plate 21 as shown in FIG. 4. The cooling plate 21 comprises a substantially similar shape to the backplate 7 of the power controller 4. That is, the cooling plate 21 is cuboidal, having a first major side 22, a second major side 23, a first minor side 24, and a second minor side 25, and the first and second major sides 22, 23 are longer than the first and second minor sides 24, 25. The cooling plate 21 is substantially planar, with a depth that is significantly less than the length of the minor and major sides 22, 23, 24, 25. In this example, the first and second major sides 22, 23 are parallel to each other, the first and second minor sides

24, 25 are parallel to each other, and the first and second major sides 22, 23 are perpendicular to the first and second minor sides 24, 25. In this way, the cooling plate 21 has a top surface 26 and a bottom surface 27.

As illustrated, the top surface 26 of the cooling plate 21 includes a recess 28. The power controller 4 is attachable to the cooling plate 21 such that it covers the recess 28. The recess 28 defines a cooling fluid chamber 29, shown most clearly in FIG. 4.

In this example, the top surface 26 of the cooling plate 21 includes a mounting surface 30 that is receded from the top surface 26 of the cooling plate 21. The mounting surface

30 is adapted to receive the power controller 4. The mounting surface 30 includes

-Ίfixing holes 31 that correspond to fixing holes 32 in the backplate 7 of the power controller 4 (see FIG. 2) for attaching the power controller 4 to the cooling plate 21.

In this example, the recess 28 is cuboidal, having a first major side 33, a second major 5 side 34, a first minor side 35, and a second minor side 36, the first and second major sides 33, 34 being longer than the first and second minor sides 35, 36. In this example, the first and second major sides 33,34 are parallel to each other, the first and second minor sides 35,36 are parallel to each other, and the first and second major sides 33, are perpendicular to the first and second minor sides 35,36.

The cooling plate 21 also includes an inlet 37 and an outlet 38. The inlet is formed in the first minor side 24 of the cooling plate and extends through to the first minor side of the recess 28, and the outlet 38 is formed in the second minor side 25 of the cooling plate 21 and extends through to the second minor side 26 of the recess 28, such that the inlet and the outlet are disposed at opposing ends of the cooling plate 21.

As illustrated in FIG. 4, the backplate 7 of the power controller 4 includes a plurality of protrusions 66 that extend into the cooling fluid chamber 29. The protrusions 66 increase the surface area of the backplate 7 that is exposed to the cooling fluid, thereby increasing heat transfer to the cooling fluid.

As indicated in FIG. 4, during use cooling fluid enters the cooling fluid chamber 29 through the inlet 37 and exits via the outlet 38. While the cooling fluid is in the cooling fluid chamber 29 it absorbs heat from the power controller 4, in particular via the backplate 7 and protrusions 66. The cooling fluid carries the absorbed heat out of the outlet 38. The cooling fluid can then be passed through a cooler, for example a radiator or heat exchanger, before the cooling fluid is circulated back to the inlet 37. In this way, the power controller 4 is cooled and excess heat is dispersed.

Disadvantageously, the first of the switching transistors 8, being arranged adjacent to the inlet 37, is cooled to a greater extent than the second switching transistor 9 and the third switching transistor 10, which are further from the inlet 37. This creates a temperature gradient across the power controller 4, and temperature differences between the individual switching transistors 8, 9,10. This is due to the cooling fluid having a lower temperature at the inlet 37.

-8FIG. 5 illustrates the bottom surface of the backplate 7 that faces the cooling fluid chamber 29. An array of protrusions 66 re illustrated.

As shown in FIG. 5, the arrangement of the protrusions 66 can result in stagnant areas 5 within the cooling fluid chamber 29, where the cooling fluid does not flow adequately, resulting in hot spots on the power controller 4. In particular, the protrusions 66 of a power controller 4 are typically arranged in rows and columns that are offset from each other to define diagonal paths between the protrusions 66, as shown in FIG. 5. As cooling fluid enters the cooling fluid chamber 28 at the inlet 37 in the first minor side

35 of the cooling fluid chamber 29, it will flow along the diagonal paths towards the first and second major sides 33,34 of the cooling fluid chamber 29, along the first and second major sides 33,34 of the cooling fluid chamber 29, and then towards the outlet 38 in the second minor side 36 of the cooling fluid chamber 29. This results in a stagnant area in the middle of the cooling fluid chamber 29 where cooling fluid does not flow adequately, reducing the cooling efficiency in the middle of the cooling fluid chamber 29. In this way, the second switching transistor 9 (see FIG. 2) maybe inadequately cooled.

FIGS. 6, 7 and 8 illustrate a first example cooling plate 40 of the present invention. In this example, the cooling plate 40 is cuboidal and adapted such that the power controller 4 (see FIG. 2) is attachable to the cooling plate 40. The cooling plate 40 is substantially cuboidal, having a first major side 41, a second major side 42, a first minor side 43, and a second minor side 44. The first and second major sides 41,42 are longer than the first and second minor sides 43, 44. The cooling plate 40 is substantially planar, having a depth which is less than the length of the first and second minor sides 43,44. In this example, the cooling plate 40 is cuboidal, i.e. the first and second major sides 41, 42 are parallel to each other, the first and second minor sides 43, 44 are parallel to each other, and the first and second major sides 41, 42 are perpendicular to the first and second minor sides 43, 44. In this way, the cooling plate

40 has a top surface 45 and a bottom surface 46.

As illustrated, the top surface 45 of the cooling plate 40 includes a recess 47. The power controller 4 (see FIG. 2) is attachable to the cooling plate 40 such that it covers the recess 47. In this way, the recess 47 defines a cooling fluid chamber 48.

-9The top surface 45 of the cooling plate 40 includes a mounting surface 49 adapted to receive the power controller 4. The mounting surface 49 includes fixing holes 50 that correspond to the mounting holes 32 in the power controller 4, as illustrated in FIG. 2, for attaching the power controller 4 to the cooling plate 40. In this example, the mounting surface 49 is sunk relative to the top surface 45 of the cooling plate 40. However, it will be appreciated that the mounting surface 49 may alternatively be formed on the top surface 45 of the cooling plate 40. The mounting surface 49 is the surface in which the fixing holes 50 are provided.

In this example, the recess 47 is cuboidal, having a first major side 51, a second major side 52, a first minor side 53, and a second minor side 54, the first and second major sides 51, 52 being longer than the first and second minor sides 53, 54. In this example, the first and second major sides 51, 52 are parallel to each other, the first and second minor sides 53,54 are parallel to each other, and the first and second major sides 51, 52 are perpendicular to the first and second minor sides 53, 54.

The bottom surface 55 of the recess 47 is opposite to the backplate 7 of the power controller 4 (see FIG. 2) when the power controller 4 is attached to the cooling plate 40.

In this example, the cooling plate includes an inlet 56 and an outlet 57. The inlet 56 and outlet 57 are disposed in the first major side 41 of the cooling plate 40. The inlet 56 and the outlet 57 each have a conduit 64, 65 that extends into the cooling plate 40, as illustrated in FIG. 7. That is, the inlet conduit 64 and the outlet conduit 65 extend in a planar direction from the first major side 41 of the cooling plate 40.

As illustrated, the bottom surface 55 of the recess 47 includes three inlet holes 58,59, 60 and three outlet holes 61, 62, 63. The three inlet holes 58,59, 60 are arranged adjacent to the first major side 51 of the recess 47, and the three outlet holes 61, 62, 63 are arranged adjacent to the second major side 52 of the recess 47. In particular, the three inlet holes 58,59, 60 are each spaced from the first major side 51 of the recess 47 by a distance less than the width of the three inlet holes 58,59, 60, for example by a distance that is approximately 70% of the width of the three inlet holes 58,59, 60. Similarly, the three outlet holes 61, 62, 63 are each spaced from the second major side 52 of the recess 47 by a distance less than the width of the three outlet holes 61, 62, 63, for example by a distance that is approximately 70% of the width of the three outlet holes 61, 62, 63.

- 10 In addition, each inlet hole 58,59, 60 is aligned with an outlet hole 61, 62, 63.

Moreover, each pair of inlet hole 58,59, 60 and outlet hole 61, 62, 63 is aligned with a switching transistor 8, 9,10 of the power controller 4, as shown in FIG. 7. As illustrated, in this example inlet hole 58 and outlet hole 61 are aligned with each other and with switching transistor 8; inlet hole 59 and outlet hole 62 are aligned with each other and with switching transistor 9; and, inlet hole 60 and outlet hole 63 are aligned with each other and with switching transistor 10. In particular, the inlet holes 58, 59, and outlet holes 61, 62, 63 are aligned with the centres of the switching transistors

8, 9,10. The inlet holes 58, 59, 60 are aligned with first ends of the switching transistors 8, 9,10, and the outlet holes 61, 62, 63 are aligned with the opposing ends of the switching transistors 8, 9,10.

As also illustrated, the inlet conduit 64 connects the inlet 56 to all of the inlet holes 58,

59, 60 in the bottom surface 55 of the recess 47.

In particular, the inlet conduit 64 extends from the inlet 56 on the first major side 41 of the cooling plate 40, in a planar direction towards the recess 47 and connects to all of the inlet holes 58,59, 60. As illustrated, the inlet conduit 64 extends in a direction parallel to the first and second minor sides 43,44 of the cooling plate 40 and then bends at bend 66 to extend parallel to first and second major sides 41, 42 of the cooling plate 40 on the opposite side of the recess 47 to the inlet 56. This section 68 of the inlet conduit 64 is parallel to and adjacent the second major side 52 of the recess 47 and is connected to the three inlet holes 58, 59,60 via connecting conduits 69, 70, 71. As also illustrated, the inlet conduit 64 includes an ‘S’ bend 67 that ensures that the inlet conduit 64 avoids the recess 47 in the cooling plate 40.

As also illustrated, the outlet conduit 65 connects the outlet 57 to all of the outlet holes 61, 62, 63 in the bottom surface 55 of the recess 47.

In particular, the outlet conduit 65 extends from the outlet 57 on the first major side 41 of the cooling plate 40, in a planar direction towards the recess 47 and connects to all of the outlet holes 61, 62, 63. As illustrated, a section 73 of the outlet conduit 65 extends in a direction parallel to the first and second minor sides 43,44 of the cooling plate 40 and then bends a bend 74 into section 72 that extends parallel to first and second major sides 41,42 of the cooling plate 40 on the side of the recess 47 that is closest to the first

- 11 major side 51 of the cooling plate 40. This section 72 of the outlet conduit 65 is parallel to and adjacent the first major side 51 of the recess 47 and connected to the three outlet holes 61, 62, 63 via connecting conduits 75, 76, 77.

As illustrated in FIG. 8, the inlet conduit 64 and outlet conduit 65 are at a level beneath the recess 47 within the cooling plate 40. The connecting conduits 69, 70, 71, 75, 76, 77 each include a bend 78 that ensures that the connecting conduits 69, 70, 71, 75, 76, 77 are parallel to the inlet holes 58, 59, 60 and outlet holes 61, 62, 63.

In use, cooling fluid is provided to the inlet 56, passes into the cooling fluid chamber 48 via the inlet conduit 64 and three inlet holes 58, 59, 60, passes through the cooling fluid chamber 48, out of the three outlet holes 61, 62, 63, outlet conduit 65, and to the outlet 57. While the cooling fluid is in the cooling fluid chamber 48 it absorbs heat from the power controller 4, in particular via the backplate 7. The cooling fluid carries the absorbed heat out of the outlet 57. The cooling fluid can then be passed through a cooler, for example a radiator or heat exchanger, before the cooling fluid is circulated back to the inlet 56. In this way, the power controller 4 is cooled and excess heat is dispersed.

The inlet conduit 64 and outlet conduit 65 are arranged such that the length of the fluid path between the inlet 64 and the outlet 65 is the same no matter which inlet hole 58, 59, 60 and outlet hole 61, 62, 63 the fluid passes through. This ensures even cooling of all three switching transistors 8, 9,10.

Moreover, the provision of one inlet hole 58,59, 60 and one outlet hole 61, 62, 63 per switching transistor 8, 9,10, and the alignment between the inlet holes 58, 59, 60, outlet holes 61, 62, 63 and switching transistors 8, 9,10 ensures that each switching transistor 8, 9,10 is effectively cooled, and also ensures even cooling of each switching transistor 8, 9,10.

Furthermore, by providing the inlet holes 58,59, 60 adjacent the first major side 51 of the recess 47, and the outlet holes adjacent the second major side 52 of the recess 47, during use the cooling fluid takes the shortest possible route through the cooling fluid chamber 48, thereby ensuring effective cooling as the cooling fluid does not heat up as much while moving through the cooling fluid chamber 48 compared to the arrangement described with reference to FIG. 3 and FIG. 4.

- 12 As illustrated in FIG. 8 the backplate 7 of the power controller 4 may include protrusions 63. The protrusions 63 extend from the backplate 7 into the cooling fluid chamber 48 and increase the surface area of the power controller 4 that is exposed to the cooling fluid chamber 48, thereby increasing heat transfer from the power controller 4 to the cooling fluid during use. The protrusions 63 are arranged in the same pattern as illustrated in FIG. 5. In particular, the protrusions 63 are arranged in columns and offset rows so that diagonal paths are defined between the protrusions 63.

The protrusions 63 are preferably integral to the backplate 7, but in alternative examples the protrusions 63 maybe attached to the backplate 7, for example via a fastener or by welding. The backplate 7 and the protrusions 63 are preferably made from a material with high thermal conductivity. In a preferred example, the backplate 7 and protrusions 63 are made of a ceramic, but in other examples the backplate 7 and protrusions 63 are made of a metal, such as aluminium. In one example, the protrusions 63 are cylindrical pins. In another example, the protrusions 63 are conical. However, it will be appreciated that the protrusions 63 maybe any shape that increases the surface area of the backplate 7 that is exposed to cooling fluid during use.

The arrangement of the inlet holes 58,59, 60 and outlet holes 61, 62, 63 in the described manner creates three distinct flows of cooking fluid across the cooling fluid chamber 48. These distinct flows of cooling fluid will each prevent the other from spreading sideways along the diagonal paths between the protrusions 63, towards the first and second minor walls 53, 54 of the recess 47. This ensures more even flow of cooling fluid through all parts of the cooling fluid chamber 48, thereby eliminating any stagnant areas when cooling fluid does not flow adequately.

FIG. 9 shows a further example cooling plate 40, having the recess 47 that forms the cooling fluid chamber 48, as described above. In this example, the cooling plate 40 further includes a heat sink 65. As shown, the cooling plate 40 is larger than in the examples described above, and the recess 47 is formed towards one end of the cooling plate 40. The other part of the cooling plate 40 provides a heat sink 65. The inlet and outlet conduits 64, 65 (see FIG. 7) extend through the heat sink part 65 of the cooling plate 40 to the recess 47. The cooling plate 40 is preferably made from a thermally conductive material, for example a metal such as aluminium. In this way, excess heat

-13from the power controller is drawn into the heat sink 65, which further improves the operating temperature of the power controller.

It will be appreciated that the cooling plate may alternatively be provided with further inlet holes and outlet holes, for example multiple inlet holes and outlet holes may be provided per switching transistor. In addition, if more than three switching transistors are provided in a power controller then the cooling plate may comprise further inlet holes and outlet holes, so that each switching transistor has at least one inlet hole and at least one outlet hole associated with it.

In some examples, the cooling plate is a part of an enclosure that surrounds the power controller. For example, the enclosure may include a cooling plate to which the power controller is attached and a cover that covers the other side of the power controller.

The cooling system may further include a pump that circulates the cooling fluid through the cooling fluid chamber. The pump can be connected to the inlet and optionally also to the outlet. The cooling fluid may be a liquid, for example water, Betaine, or Polyalkylene glycol. The cooling fluid may include additives, for example corrosion inhibitors. Alternatively, the cooling fluid may be a gas, for example air.

The embodiments of the invention shown in the drawings and described above are exemplary⁷ embodiments only and are not intended to limit the scope of the invention, which is defined by the claims hereafter. It is intended that any combination of nonmutually exclusive features described herein are within the scope of the present invention.

Claims

Claims

l. A cooling plate for a power controller, the power controller comprising a plurality of switching transistors;

wherein the cooling plate comprises a recess and a mounting surface adapted 5 such that said power controller is attachable to the mounting surface to cover the recess and define a cooling fluid chamber, the recess comprising an opposing surface that faces said power controller when said power controller is attached to the mounting surface;

wherein the opposing surface of the recess comprises a plurality of cooling fluid io inlet holes and a plurality of cooling fluid outlet holes, and wherein at least one cooling fluid inlet hole and at least one cooling fluid outlet hole is aligned with each of said plurality of switching transistors when said power controller is attached to the mounting surface.

15
2. The cooling plate of claim 1, further comprising an inlet conduit that is in fluid communication with each cooling fluid inlet hole.
3. The cooling plate of claim 2, wherein the inlet conduit extends to an inlet formed on a side of the cooling plate.
4. The cooling plate of any preceding claim, further comprising an outlet conduit that is in fluid communication with each cooling fluid outlet hole.
5. The cooling plate of claim 4, wherein the outlet conduit extends to an outlet 25 formed on a side of the cooling plate.
6. The cooling plate of claim 3, further comprising an outlet conduit that is in fluid communication with each cooling fluid outlet hole, wherein the outlet conduit extends to an outlet formed on the side of the cooling plate.
7. The cooling plate of claim 6, wherein the inlet conduit and the outlet conduit are configured such that the length of the path from the inlet to the outlet is the same via each cooling fluid inlet hole and cooling fluid outlet hole.

-158. The cooling plate of any preceding claim, wherein the opposing surface of the recess comprises one cooling fluid inlet hole per switching transistor and one cooling fluid outlet hole per switching transistor.

5 9. The cooling plate of claim 8, wherein the cooling fluid inlet hole and cooling fluid outlet hole associated with each switching transistor are disposed at opposing ends of said switching transistor.

io. The cooling plate of any preceding claim, wherein the cooling fluid inlet holes io are arranged adjacent to a first side of the recess, and the cooling fluid outlet holes are arranged adjacent to a second side of the recess, the second side being opposite to the first side.

it. The cooling plate of any preceding claim, wherein the recess is rectangular and

15 comprises first and second major sides and first and second minor sides, the first and second major sides being longer than the first and second minor sides, and wherein the switching transistors are arranged in a line formed between the first and second minor sides.

20 12. The cooling plate of claim n, wherein the cooling fluid outlet holes are arranged in a line adjacent to the first major side of the recess, and the cooling fluid inlet holes are arranged in a line adjacent to the second major side of the recess.

13. The cooling plate of claim 12, wherein each cooling fluid inlet hole is aligned

25 with a cooling fluid outlet hole in a direction of the first and second minor sides of the recess.

14. The cooling plate of any preceding claim, wherein the cooling plate comprises a thermally conductive material.

15. The cooling plate of any preceding claim, wherein the cooling plate comprises a heat sink.

16. A power control assembly comprising:

35 a power controller having a plurality of switching transistors; and a cooling plate according to any preceding claim.

-ι617. The power control assembly of claim 16, wherein the power controller comprises a backplate, and wherein the plurality of switching transistors are attached to the backplate, the backplate being attached to the mounting surface.

18. The power control assembly of claim 17, wherein the backplate comprises a plurality of protrusions that extend into the cooling fluid chamber towards the opposing surface.
10 19. The power control assembly of claim 18, wherein the plurality of protrusions are conical.

20. The electronic power control assembly of any of claims 16 to 19, wherein the protrusions are arranged in columns and offset rows.

21. The power control assembly of any of claims 16 to 20, further comprising a pump arranged to circulate cooling fluid through the cooling fluid chamber via the cooling fluid inlet holes and cooling fluid outlet holes.

20 22. The power control assembly of any of claims 16 to 21, wherein the power controller comprises three switching transistors.

23. A vehicle comprising the power control assembly of any of claims 16 to 22.

25 24. The vehicle of claim 23, further comprising an electric motor arranged to provide a driving force for the vehicle.

25. The vehicle of claim 23 or claim 24, wherein the vehicle is an electric, hybrid, or range-extended vehicle.

Intellectual

Property

Office

Application No: GB1703651.8