COOLING SYSTEM FOR ELECTRONICS

Abstract

Cooling system for electronics, which includes: a housing (110) containing: a base section (120) with sides (121) and a bottom surface (123) that define a cavity; and a cover section (116) that encloses the base section (120) and contains cooling elements (118, 119) attached to it; electronic components; a shield (244) which is arranged in the cavity between the electronic components and the cover section (116); a vertical element arranged below the shield (244) to define a first fluid chamber between one side of the vertical element and one side of the base section (120) and a second fluid chamber between an opposite side of the vertical element and another side of the base section (120), wherein the electronic components are arranged in the second fluid chamber; and a cooling fluid (260) arranged in the cavity and having a fluid level below at least one section of the shielding (244), and either: the housing (110) is mounted at an angle of inclination relative to the horizontal; or the housing (110) is mounted parallel to the horizontal and the shielding (244) is mounted at an angle of inclination relative to the horizontal; characterized by the fact that an upper edge of the vertical element is connected to an edge of the shield (244); or that an upper edge of the vertical element and an edge of the shield (244) are arranged below the fluid level; or that a lower edge of the vertical element contains several openings to allow a fluid to flow from the first fluid chamber to the second fluid chamber; or that the vertical element contains a gate printed circuit board (gate PCB) (254); or that the electronic components comprise at least one power inverter (250), busbars (210), a current sensor (253) and a volume capacitor (224); or that the electronic components comprise: a power inverter module (250) containing several circuit breakers; a current sensor (253) which is connected to the power inverter module (250) via first busbars (210); AC busbars (128) connected to the current sensor (253); a volume capacitor (224) which is connected to the power inverter module (250) via second busbars (210); and DC busbars (132) connected to the volume capacitor (224).

Description

INTRODUCTION

[0001] The present invention relates to a cooling system for electronics and in particular to a system for cooling the power electronics using a thermosiphon.

[0002] A generic cooling system is essentially derived from US 11 252 840 B2.

[0003] Further details of the state of the art can be found in US 2010 / 0 328 890 A1.

[0004] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, contain one or more electric machines and a battery system that includes one or more battery cells, one or more battery modules, and / or one or more battery assemblies to provide propulsion power. EVs include a power control system, which contains a power inverter module that controls the power to and from the battery system during charging, propulsion, and / or regeneration. During operation, the electrical components of the power control system, such as the inverter, control board, gate control board, busbars, and other components, may require cooling. SUMMARY

[0005] According to the invention, a cooling system for electronics is presented, which is characterized by the features of claim 1.

[0006] Other features include a hydrophobic coating on the upward-facing surface of the shield. The cover section is made of metal, with cooling elements extending from both the top and bottom of the cover section. The cooling elements comprise tubes.

[0007] Another cooling system for electronics comprises a housing consisting of a base section, which includes sides and a bottom surface defining a cavity, and a cover section that encloses the base section and contains attached cooling elements. A power inverter module contains several power switches. A shield is arranged in the cavity beneath a control printed circuit board (PCB). A gate PCB is arranged vertically within the housing and defines a first fluid chamber between one side of the gate PCB and one side of the base section, and a second fluid chamber between an opposite side of the gate PCB and another side of the base section. The power inverter module is located in the second fluid chamber. A cooling fluid is arranged in the cavity and has a fluid level below at least one section of the shield.The housing is mounted at an angle relative to the horizontal, or the housing is mounted parallel to the horizontal and the shielding is mounted at an angle relative to the horizontal.

[0008] According to other features, the gate circuit board is connected to an edge of the shield. A lower edge of the shield is located below the fluid level. A lower edge of the gate circuit board contains several openings to allow fluid to flow from the first fluid chamber to the second fluid chamber. The power inverter module contains several circuit breakers. A current sensor is connected to the power inverter module via the first busbars. The AC busbars are connected to the current sensor. A volumetric capacitor is connected to the inverter module via the second busbars. The DC busbars are connected to the volumetric capacitor.

[0009] According to other specifications, the current sensor, AC busbars, volumetric capacitor, and DC busbars are located in the second fluid chamber. A hydrophobic coating is applied to the upward-facing surface of the shield. The cover section is made of metal, with cooling elements extending from both the top and bottom of the cover section. The base section is also made of metal. The cooling elements comprise tubes.

[0010] Further applications of the present invention will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples serve only for illustration. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be more fully understood from the detailed description and the accompanying drawings; these show: Fig. 1 a perspective view of an example of a power inverter arrangement according to the present invention; Fig. 2 a lateral cross-sectional view of an example of a power inverter arrangement according to the present invention; Fig. 3 an end view of an example of the power inverter arrangement according to the present invention; Fig. 4 a functional block diagram of an electric motor arrangement comprising a power inverter arrangement according to the present invention; and Fig. 5 a lateral cross-sectional view of another example of a power inverter arrangement according to the present invention.

[0012] Reference symbols can be used multiple times in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0013] While the systems and methods for cooling the power electronics according to the present invention are described below in the context of the power electronics of a power inverter arrangement for an EV, the systems and methods for cooling the power electronics can be used with other types of electronics and / or in non-vehicle applications.

[0014] The systems and methods for cooling power electronics according to the present invention provide improved two-phase immersive cooling for power electronics. The cooling system forms a thermosiphon within a sealed housing. The cooling system generates a self-sustaining and self-enhancing flow rate of the cooling fluid without the use of a pump. The systems and methods for cooling the power electronics improve the system's cooling capacity, reduce its weight, and increase the EV's range.

[0015] In some examples, a shield is used within the sealed enclosure to reduce electromagnetic interference. At least part of the shield's surface is located above the coolant level within the sealed enclosure. The shield is coated with a hydrophobic layer to improve the collection and flow of the condensed coolant.

[0016] During operation, the heat generated by the power electronics evaporates the coolant. The coolant vapor rises and is condensed by the cooling elements attached to a cover section of the enclosure. The condensed fluid drips onto the shield and flows into a first fluid chamber located between one side of a vertical element (such as a gate circuit board) and one side of a base section of the enclosure. This creates a hydrostatic pressure imbalance between the coolant in the first fluid chamber and the coolant in a second chamber (located between an opposite side of the vertical element and another side of the base section). The denser fluid flows downwards in the first fluid chamber and continues to flow into the second fluid chamber. The coolant in the second fluid chamber evaporates, and the process repeats.This process corresponds to a thermosiphon cycle, which is controlled by the density differences and the heat dissipation from the power electronics.

[0017] In Fig. Figure 1 shows a power inverter assembly 100. The power inverter assembly 100 comprises a housing 110 with a base section 120 and a cover section 116. According to some examples, the base section 120 and the cover section 116 have a rectangular cross-section, although other shapes can be used. According to some examples, the cover section 116 and the base section 120 are made of a metal, such as aluminum or steel, although other materials can be used. The base section 120 includes the sides 121 and a bottom surface 123, which define an internal cavity. According to some examples, the cover section 116 provides a seal with the cavity of the base section 120.

[0018] The cover section 116 contains the cooling elements 118, which extend upwards (shown) and downwards (the cooling elements 119 in Fig. 2) extend to create a heat exchange between the evaporated cooling fluid in the cavity and the surroundings. According to some examples, cooling elements 118 and 119 include an arrangement of tubes made of metal, such as aluminum or steel, having a predetermined length and a circular cross-section, although other types of cooling elements may be used.

[0019] The AC busbars 128 extend from one of the sides 121 of the housing 110. The DC busbars 132 extend from another of the sides 121 of the housing 110. The AC busbars 128 are connected to an electric motor ( Fig. 4), while the DC busbars 132 are connected to the battery system.

[0020] In Fig. Figure 2 shows the power inverter assembly 100 in more detail. The electrical components of the power inverter assembly 100 are arranged in the base section 120. The electrical components of the power inverter assembly 100 include the busbars 210, which provide the connections to and from a power inverter module 250. The AC busbars 128 are connected to a current sensor 253. The busbars 210 connect the current sensor 253 to the power inverter module 250. The power inverter module 250 contains an arrangement of circuit breakers that are opened and closed during operation to control the power supplied from the battery system to the electric motor (during drive operation) and / or to return power from the electric motor (during regeneration) or from a utility company (during charging) to the battery system.The power inverter module 250 can also include the cooling fins 252 to exchange heat with a cooling fluid 260 that partially fills the base section 120.

[0021] The busbars 210 also connect the power inverter module 250 to a volume capacitor 224, which is connected to the DC busbars 132 (and is partially or completely immersed in the cooling fluid 260). The gate terminals 255 connect the power inverter module 250 to a gate circuit board (gate PCB) 254 (which is also partially or completely immersed in the cooling fluid 260). The gate PCB 254 provides gate control signals to control the circuit breakers in the power inverter module 250.

[0022] A shield 244 is positioned between a control PCB 242 and the power inverter module 250 and other components. The control PCB 242 communicates with a vehicle controller, the current sensor 253, and / or other components, and sends control signals to the gate PCB 254. In some examples, the control PCB 242 has a width and length smaller than the corresponding dimensions of the shield 244 to define a channel around two or more edges of the control PCB 242. This channel allows the condensed fluid to return to the first fluid chamber via the shield 244. In some examples, the shield 244 reduces electromagnetic interference (EMI) to ensure electromagnetic compatibility (EMC) between the control PCB 242, the gate PCB 254, and other components in the base section.

[0023] According to some examples, the shield 244 incorporates a hydrophobic coating 245 on its upper surface. The hydrophobic coating 245 increases the flow of the condensed cooling fluid to the first fluid chamber, which is defined between side 121 of the housing 110 and the gate PCB 254. The hydrophobic coating 245 reduces the wettability of the fluid on the surface (according to some examples, the contact angle is greater than 150°) and consequently accelerates the movement of the condensed droplets.

[0024] According to this example, the housing 110 is mounted at an inclined position relative to a horizontal plane to cause the condensed fluid to drain into the first fluid chamber. Because the housing 110 is inclined, the shield 244 can be arranged parallel to the bottom surface 123 of the housing 110. According to some examples, the base section 120 and / or the shield 244 are inclined at a predetermined angle (relative to the horizontal) in a range between 2° and 20°, although other angles can be used. According to some examples, the base section 120 is inclined at a predetermined angle (relative to the horizontal) in a range between 3° and 10°, although other angles can be used.

[0025] The cooling fluid 260 fills the chamber up to a predetermined fluid level. According to some examples, the predetermined fluid level is below some or all of the shielding 244 and above some or all of the power inverter module 250. When the components of the power inverter assembly 100 heat up during operation, the cooling fluid 260 absorbs the heat. Some of the cooling fluid 260 evaporates due to the heat, as shown in Figure 280.

[0026] The evaporated fluid 280 rises and is cooled by the cooling elements 118 and 119 of the cover section 116. The evaporated fluid 280 condenses, with the condensed cooling fluid 282 falling from the cooling elements 119 onto the shield 244. Due to the inclined mounting position of the housing 110, the condensed cooling fluid 282 flows downwards (left) along the control PCB 242 and / or the shield 244. Fig. 2) The condensed cooling fluid 282 flows downwards into the first fluid chamber and through one or more openings 264 located at a lower edge of the gate PCB 254. The cooling fluid 260 is vaporized, with the thermosiphon process continuing to create a cycle from liquid cooling fluid to vapor cooling fluid to liquid cooling fluid, etc.

[0027] In some examples, a lower edge of the shield 244 is connected to the gate PCB 254 to separate the cooling fluid into the first and second (or main) fluid chambers. The first fluid chamber is located on one side of the gate PCB 254. The bubbles that form float out of the second fluid chamber (where the hot power electronics are located) to form a siphon. In other examples, the lower end of the shield 244 can be immersed in the cooling fluid to achieve the same siphon structure without requiring a connection between the edges of the gate PCB and the shield 244. In some examples, the gate PCB 254 is oriented vertically and positioned on one side of the housing to form the first fluid chamber together with the side 121 of the housing 110. The openings 264 in the lower edge of the gate PCB 254 create a flow channel to the heat source in the second or main fluid chamber.

[0028] In Fig. Figure 3 shows an end view of the components of the power inverter assembly 100 (excluding the housing 110). The gate PCB 254 contains three of the openings 264 located along a lower edge 310 of the gate PCB 254, although fewer or additional openings 264 can be used.

[0029] In Fig. 4. The power inverter assembly 100 can be connected to or integrated with an electric motor assembly 410. The power inverter assembly 100 and / or the power inverter assembly 100 and the electric motor assembly 410 can be mounted in the inclined position.

[0030] In Fig. 5. The base surface 123 of the housing 110 of the power inverter assembly 100 can be mounted parallel to a horizontal position. According to this example, the control PCB 242 and / or the shield 244 can be mounted at an angle relative to the base surface 123 of the housing 110.

Claims

[1] Cooling system for electronics, which includes: a housing (110) containing: a base section (120) with sides (121) and a bottom surface (123) that define a cavity; and a cover section (116) that encloses the base section (120) and contains cooling elements (118, 119) attached to it; electronic components; a shield (244) which is arranged in the cavity between the electronic components and the cover section (116); a vertical element arranged below the shield (244) to define a first fluid chamber between one side of the vertical element and one side of the base section (120) and a second fluid chamber between an opposite side of the vertical element and another side of the base section (120), wherein the electronic components are arranged in the second fluid chamber; and a cooling fluid (260) arranged in the cavity and having a fluid level below at least one section of the shielding (244), and either: the housing (110) is mounted at an angle of inclination relative to the horizontal; or the housing (110) is mounted parallel to the horizontal and the shielding (244) is mounted at an angle of inclination relative to the horizontal; characterized by , that an upper edge of the vertical element is connected to an edge of the shield (244); or that an upper edge of the vertical element and an edge of the shield (244) are arranged below the fluid level; or that a lower edge of the vertical element contains several openings to allow a fluid to flow from the first fluid chamber to the second fluid chamber; or that the vertical element contains a gate printed circuit board (gate PCB) (254); or that the electronic components comprise at least one power inverter (250), busbars (210), a current sensor (253) and a volume capacitor (224); or that the electronic components comprise: a power inverter module (250) containing several circuit breakers; a current sensor (253) which is connected to the power inverter module (250) via first busbars (210); AC busbars (128) connected to the current sensor (253); a volume capacitor (224) which is connected to the power inverter module (250) via second busbars (210); and DC busbars (132) connected to the volume capacitor (224). [2] Cooling system according to claim 1, further comprising a hydrophobic coating (245) on an upwardly facing surface of the shielding (244). [3] Cooling system according to claim 1, wherein the cover section (116) is made of metal and the cooling elements (118, 119) extend from the top and bottom of the cover section (116). [4] Cooling system according to claim 1, wherein the cooling elements (118, 119) comprise tubes.

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