Patent Application
20220293355
The subject matter herein relates generally to contactors.
Certain electrical applications, such as HVAC, power supply, locomotives, elevator control, motor control, aerospace applications, electric vehicles, hybrid electric vehicles, fuel-cell vehicles, charging systems, and the like, utilize electrical contactors to control power distribution for the devices. For example, vehicles using a high-voltage battery pack generally include a contactor to switch battery power to the power electronic components. There is a desire to increase current carrying capacity through components of the contactor. However, an increase in current leads to overheating of the components of the contactor.
A need remains for a contactor having high current carrying capacity.
In one embodiment, a contactor is provided. The contactor includes a housing having an outer wall defining a cavity. The housing has a first end and a second end opposite the first end. The contactor includes a switch assembly received in the cavity. The switch assembly includes a first fixed contact received in the cavity and a second fixed contact received in the cavity. The switch assembly includes a movable contact movable within the cavity between a mated position and an unmated position. The movable contact engages the first and second fixed contacts to electrically connect the first and second fixed contacts in the mated position. The switch assembly includes a coil assembly in the cavity operated to move the movable contact between the unmated position and the mating position. The contactor includes a heat transfer device coupled to the housing. The heat transfer device is thermally coupled to the first fixed contact and the second fixed contact to dissipate heat from the first fixed contact and the second fixed contact.
In a further embodiment, a contactor is provided. The contactor includes a housing having an outer wall defining a cavity. The housing has a first end and a second end opposite the first end. The contactor includes a switch assembly received in the cavity. The switch assembly includes a first fixed contact received in the cavity and a second fixed contact received in the cavity. The switch assembly includes a movable contact movable within the cavity between a mated position and an unmated position. The movable contact engages the first and second fixed contacts to electrically connect the first and second fixed contacts in the mated position. The switch assembly includes a coil assembly in the cavity operated to move the movable contact between the unmated position and the mating position. The contactor includes a heat transfer device coupled to the housing. The heat transfer device includes a cold plate has a coolant channel therethrough. The cold plate includes a thermal interface thermally coupled to the first fixed contact and the second fixed contact to dissipate heat from the first fixed contact and the second fixed contact with aid of coolant fluid flowing through the coolant channel.
In another embodiment, a contactor is provided. The contactor includes a housing having an outer wall defining a cavity. The housing has a first end and a second end opposite the first end. The contactor includes a switch assembly received in the cavity. The switch assembly includes a first fixed contact received in the cavity and a second fixed contact received in the cavity. The switch assembly includes a movable contact movable within the cavity between a mated position and an unmated position. The movable contact engages the first and second fixed contacts to electrically connect the first and second fixed contacts in the mated position. The switch assembly includes a coil assembly in the cavity operated to move the movable contact between the unmated position and the mating position. The contactor includes a heat transfer device coupled to the housing. The heat transfer device includes a peltier device has a thermal interface thermally coupled to the first fixed contact and the second fixed contact. The peltier device uses thermoelectric cooling to dissipate heat from the first fixed contact and the second fixed contact.
In an exemplary embodiment, the contactor 100 includes a cover 104 coupled to the housing 110 for closing the cavity 112. The cover 104 may be coupled to the bottom 116 of the contactor 100, such as to the base 114. Optionally, the cover 104 may be sealed to the housing 110. In various embodiments, the cover 104 is manufactured from a thermally conductive material. The cover 104 is thermally coupled to the mounting structure 102. The cover 104 dissipates heat from internal components of the contactor 100 to the mounting structure 102, where the heat is transferred away from the cover 104 and the contactor 100. Optionally, outer wall 111 of the housing 110 above the base 114 may be cylindrical defining a cylindrical cavity 112 in various embodiments.
The switch assembly 118 of the contactor 100 includes fixed contacts 120 received in the cavity 112 and a movable contact 122 movable within the cavity 112 between a mated position and an unmated position. The movable contact 122 engages the fixed contacts 120 to electrically connect the fixed contacts 120 in the mated position. In the illustrated embodiment, the contactor 100 includes first and second fixed contacts 120a, 120b. The fixed contacts 120 are fixed to the housing 110. For example, the fixed contacts 120 may be coupled to the base 114 and/or the cover 104. In other various embodiments, the fixed contacts 120 may be coupled to an insert 124 of the housing 110 inserted into the cavity 112. The insert 124 may be removable from the cavity 112 when the cover 104 is removed from the base 114. In an exemplary embodiment, the insert 124 of the housing 110 includes a contact holder 126 configured to hold the fixed contacts 120. The contact holder 126 defines an enclosure 128. The fixed contacts 120 extend into the enclosure 128. The movable contact 122 is located in the enclosure 128. The outer wall 111 surrounds the contact holder 126 and the enclosure 128.
The switch assembly 118 of the contactor 100 includes a coil assembly 150 in the cavity 112 operated to move the movable contact 122 between the unmated position and the mated position. In an exemplary embodiment, the coil assembly 150 is an electromagnet for actuating the movable contact 122. The coil assembly 150 moves the movable contact 122 to the mated position with the coil assembly 150 is energized and moves the movable contact 122 to the unmated position when the coil assembly 150 is deenergized.
In an exemplary embodiment, the contactor 100 includes an arc suppressor 152 for suppressing electrical arc of the electrical circuit. The arc suppressor 152 is located in the cavity 112 of the housing 110. Optionally, the arc suppressor 152 may be located in the contact holder 126, such as in or near the enclosure 128. In an exemplary embodiment, the arc suppressor 152 includes magnets creating magnetic fields in the enclosure 128 for suppressing arc created between the movable contact 122 and the fixed contacts 120. In an exemplary embodiment, the contact holder 126 may be sealed and may be filled with an inert gas for arc suppression.
The housing 110 holds the components of the contactor 100. The housing 110 includes a first end 160 and a second end 162 opposite the first end 160. The first end 160 may be a top of the housing 110 and the second end 162 may be a bottom of the housing 110. The housing 110 includes a first side 164 and a second side 166 opposite the first side 164. The housing 110 may include a secondary cavity 168 at the second side 166. The secondary cavity 168 may receive part of the heat transfer device 200. In the illustrated embodiment, the main cavity 112 is open at the second end 162. The cover 104 is coupled to the housing 110 at the second end 162 to close the main cavity 112.
The heat transfer device 200 is incorporated into the contactor 100 to dissipate heat from components of the contactor 100. The reduction in operating temperature of the components of the contactor 100 allows for increased current carrying capacity of the contactor 100. The heat transfer device 200 is configured to be thermally coupled to the first fixed contact 120a and the second fixed contact 120b to dissipate heat from the first and second fixed contacts 120a, 120b, which in turn lower the operating temperature of the movable contact 122. The heat transfer device 200 may directly interface with the first and second fixed contacts 120a, 120b to dissipate heat from the first and second fixed contacts 120a, 120b. Alternatively, the heat transfer device 200 may be indirectly thermally coupled to the first and second fixed contacts 120a, 120b, such as through an intermediary thermal component, such as the cover 104.
In an exemplary embodiment, the heat transfer device 200 includes a thermal conductor 202 and a thermally conductive isolator 204 between the thermal conductor 202 and the first and second fixed contacts 120a, 120b. In an exemplary embodiment, the thermal conductor 202 is a cold plate having cooling channels for active cooling by liquid coolant circulated through the thermal conductor 202. In other various embodiments, the thermal conductor 202 may include a thermoelectric cooling device, such as a peltier device for cooling the fixed contacts 120. In other various embodiments, the thermal conductor 202 includes thermal inserts used for passively cooling the fixed contacts 120, such as via conduction, convection and/or radiation. In the illustrated embodiment, the thermal conductor 202 is a single component configured to cool both the first and second fixed contacts 120a, 120b. However, in alternative embodiments, the thermal conductor 202 may have multiple components, such as a first component for cooling the first fixed contact 120a and a second component for cooling the second fixed contacts 120b.
The thermally conductive isolator 204 is electrically insulative to prevent short circuiting of the first and second fixed contacts 120a, 120b. In an exemplary embodiment, the thermally conductive isolator 204 is a metal oxide insulator. For example, the thermally conductive isolator 204 may be a ceramic pad. In other various embodiments, the thermally conductive isolator 204 may be a polymeric pad having thermally conductive fillers, such as metal particles, embedded in the polymeric pad to increase thermal conductivity. Other types of thermally conductive isolators may be used in alternative embodiments, such as aluminum nitride, boron nitride, alumina, mica. The thermally conductive isolator 204 may be a sheet or pad having a predefined shape. For example, the thermally conductive isolator 204 may be disc-shaped. In alternative embodiments, the thermally conductive isolator 204 may be an epoxy or gel applied to the surfaces of the fixed contacts 120 and/or the thermal conductor 202. In various embodiments, the thermally conductive isolator 204 may form a heat spreader. For example, the thermally conductive isolator 204 may be a homogenous material allowing heat to spread in all directions (for example, both vertically between the thermal conductor 202 and the fixed contacts 120 as well as horizontally, such as radiating outward from the hot zones of the fixed contacts 120). As such, the thermally conductive isolator 204 may efficiently transfer heat between the fixed contacts 120 and the thermal conductor 202. In an exemplary embodiment, the thermally conductive isolator 204 has a thermal conductivity (W/mK) greater than 10× a thermal conductivity of the plastic material of the housing 110. For example, the housing 110 may have a thermal conductivity of less than 1.0 W/mK while the thermally conductive isolator 204 may have a thermal conductivity of greater than 10.0 W/mK, and in some cases may be greater than 20.0 W/mK, and in even some other cases may be greater than 100.0 W/mK.
In an exemplary embodiment, the cover 104 includes a main pocket 106 that receives the heat transfer device 200. The cover 104 may include additional pockets 108 that receive the fixed contacts 120. The cover 104 holds the heat transfer device 200 relative to the fixed contacts 120. In an exemplary embodiment, the cover 104 is highly thermally conductive to help dissipate heat from the contactor 100. For example, the cover 104 may be manufactured from a metal oxide, such as a ceramic. In other various embodiments, the cover 104 may be manufactured from a polymeric material having thermally conductive fillers, such as metal particles, embedded in the polymeric material to increase thermal conductivity. In an exemplary embodiment, the cover 104 has a thermal conductivity (W/mK) greater than 10× a thermal conductivity of the plastic material of the housing 110. The cover 104 may have a thermal conductivity (W/mK) similar to the thermal conductivity of the thermal conductor 202.
The fixed contacts 120 each include a terminating end 130 and a mating end 132. The terminating end 130 is configured to be terminated to another component, such as a wire or a terminal, such as a line in or a line out wire. In an exemplary embodiment, the terminating end 130 is exposed at the exterior of the contactor 100 for terminating to the other component. The terminating end 130 may be threaded to receive a nut. In the illustrated embodiment, the terminating end 130 extends through the cover 104 and is located above the cover 104. The mating end 132 is located within the cavity 112 for mating engagement with the movable contact 122, such as when the contactor 100 is energized.
In an exemplary embodiment, the fixed contact 120 includes a plate 134. In the illustrated embodiment, the plate 134 is rectangular in shape; however, the plate 134 may have other shapes in alternative embodiments. The plate 134 may be a metal block, such as an aluminum or copper block. The plate 134 includes generally planar upper and lower surfaces. The bottom surface of the plate 134 has a large surface area, such as for thermal connection with the heat transfer device 200 (shown in
The fixed contact 120 includes one or more mating posts 136 extending from the plate 134, such as from the upper surface. In an exemplary embodiment, the mating posts 136 are metal posts, such as aluminum or copper posts. The mating posts 136 may be cylindrical having flat upper and lower surfaces. The mating posts 136 are separate and discrete from the plate 134 and coupled thereto. The mating posts 136 may be press-fit into openings in the plate 134. Alternatively, the mating posts 136 may be rivetted, brazed, soldered, welded or otherwise electrically connected to the plate 134. The mating posts 136 define the mating end 132 at distal ends 137 of the mating posts 136. The mating posts 136 are configured to be coupled to the movable contact 122. For example, movable contact 122 is configured to engage the flat distal ends 137 (for example, upper surfaces) of the mating posts 136. The mating posts 136 are thus electrically and thermally coupled to the plate 134. Dissipating heat from the plate 134 reduces the temperature of the mating posts 136, which may in turn reduce the temperature of the movable contact 122. In an exemplary embodiment, multiple mating posts 136 are provided defining parallel electrical paths between the movable contact 122 and the plate 134. Having multiple mating posts 136 lowers contact resistance through the switch assembly 118, which lowers the operating temperature of the switch assembly 118. By lowering the operating temperature of the plate 134 and the mating posts 136 allows higher current to be passed through the fixed contact 120.
In an exemplary embodiment, the fixed contact 120 includes a terminating post 138 extending from the plate 134, such as from the upper surface. The terminating post 138 may be a metal post, such as a steel, copper or aluminum post. The terminating post 138 may be generally cylindrical. The terminating post 138 defines the terminating end 130. The terminating post 138 may be threaded, such as to receive a nut. The terminating post 138 may be threadably coupled to the plate 134. Alternatively, the terminating post 138 may be press-fit, welded or otherwise coupled to the plate 134. The terminating post 138 is configured to be located exterior of the contactor for electrical connection with a power terminal or a power wire.
The movable contact 122 is movable relative to the fixed contacts 120 between a mated position and an unmated position. The movable contact 122 engages the mating posts 136 in the mated position to electrically connect the first and second fixed contacts 120a, 120b. In an exemplary embodiment, the movable contact 122 includes a metal plate 140 having planar upper and lower surfaces. The metal plate 140 extends between a first end 142 and a second end 144. The first end 142 is configured to be coupled to the mating posts 136 of the first fixed contact 120a. The second end 144 is configured to be coupled to the mating posts 136 of the second fixed contact 120b. In the illustrated embodiment, the metal plate 140 overlaps with approximately half of the distal end 137 of each mating post 136. However, the metal plate 140 may overlap with more or less of each mating post 136 in alternative embodiments, such as the entire distal ends 137 to increase the surface area at the interfaces. The metal plate 140 is thermally and electrically coupled to the mating posts 136 in the mated position. The metal plate 140 has a large surface area for high current handling. Optionally, the metal plate 140 may have a width approximately equal to widths of the plates 134. The metal plate 140 may have a thickness approximately equal to thicknesses of the plates 134.
In an exemplary embodiment, the contact holder 126 includes channels 170 passing therethrough. The channels 170 may receive contacts and/or wires for supplying power to the coil assembly 150 (shown in
The thermally conductive isolator 204 covers portions of the fixed contacts 120. For example, the thermally conductive isolator 204 covers portions of the plates 134. The thermally conductive isolator 204 covers the ends of the mating posts 136. The interface between the mating posts 136 and the plates 134 are hot spots where significant heat generation occurs. The thermally conductive isolator 204 covers the hot spots. The thermally conductive isolator 204 is thermally coupled to the fixed contacts 120 at the spots. The thermally conductive isolator 204 is used as a heat spreader to spread heat from the fixed contacts 120 to the thermal conductor 202 (shown in
In the illustrated embodiment, the thermal conductor 202 of the heat transfer device 200 includes a cold plate 210 having a coolant channel 212 therethrough. The cold plate 210 includes thermal interfaces thermally coupled to the first and second fixed contacts 120a, 120b with aid of coolant fluid flowing through the coolant channel 212. In the illustrated embodiment, the cold plate 210 is disc shaped. The cold plate 210 has a similar shape as the thermally conductive isolator 204. The cold plate 210 may have other shapes in alternative embodiments.
In various embodiments, the cold plate 210 includes a cavity 214 and a pipe 216 received in the cavity 214. The pipe 216 defines the coolant channel 212. The pipe 216 may be routed to an exterior of the cold plate 210 for connection with a coolant supply, such as using liquid fittings. For example, the ends of the pipe 216 may be routed through the secondary cavity 168, such as to a location remote from the contactor 100. In alternative embodiments, the cold plate 210 may be provided without the pipe 216. Rather, the cavity 214 itself may define the coolant channel 212. For example, a cover plate (not shown) may be brazed to the bottom of the cold plate 210 to close the cavity 214 and form the coolant channel 212.
The cold plate 210 includes a metal block. For example, the cold plate 210 may be an aluminum block or a copper block. The pipe 216 may be a copper pipe. Optionally, thermal paste or other thermal interface material may be provided between the pipe 216 and the cold plate 210. In other embodiments, the pipe 216 may be brazed to the cold plate 210. In the illustrated embodiment, the cavity 214 and the pipe 216 follow a serpentine path to provide a large amount of interface between the pipe 216 and the cold plate 210. The serpentine path allows for a long coolant channel length per surface area for improved thermal conduction from the thermal conductor 202 to the liquid coolant forced through the coolant channel 212. In an exemplary embodiment, the path of the cavity 214 and the pipe 216 passes in close proximity to the hot spots generated at the interfaces between the mating posts 136 and the plates 134. The pipe 216 may have other shapes in alternative embodiments.
The fixed contacts 120 are provided at the bottom 116 of the contactor 100. The cover 104 is coupled to the housing 110 at the bottom 116. The cover 104 may hold the fixed contacts 120 and/or the heat transfer device 200. The heat transfer device 200 is in thermal communication with the fixed contacts 120 to dissipate heat from the fixed contacts 120, and thus from the movable contact 122. The reduced operating temperatures of the components of the contactor 100 allow for an increased current carrying capacity for the circuit. The pipe 216 defines the coolant channel 212 for liquid coolant to flow through the cold plate 210 and transfer the heat away from the contactor 100. In an exemplary embodiment, the heat transfer device 200 may additional transfer heat into the mounting structure 102, which may be a heat sink or cold plate itself.
The thermoelectric cooling device 220 is held by the cover 104 and positioned in close proximity with the fixed contacts 120. The thermoelectric cooling device 220 includes upper thermal interfaces 222 configured to be thermally coupled to the fixed contacts 120 and a lower thermal interface 224 configured to dump heat from the thermoelectric cooling device 220. The upper thermal interfaces 222 are configured to be operated at different temperatures than the lower thermal interface 224. The thermoelectric cooling device 220 is manufactured from two different types of materials and creates heat flux at the junction between the two different materials. The thermoelectric cooling device 220 uses electrical energy to drive the cooling effect of the thermoelectric cooling device 220. In the illustrated embodiment, the thermoelectric cooling device 220 is rectangular in shape; however, the thermoelectric cooling device 220 may have other shapes in alternative embodiments, such as a shape similar to the shape of the fixed contacts 120 such that the thermoelectric cooling device 220 spans along the bottom surfaces of the plates 134 to entirely cover the bottom surfaces of the plates 134 of the fixed contacts 120. In various embodiments, the thermoelectric cooling device 220 may be disc shaped, such as to cover the base 114 of the housing 110 and have a large surface area for sinking the heat from the thermoelectric cooling device 220.
In an exemplary embodiment, the thermoelectric cooling device 220 includes a control circuit 230 electrically coupled to the thermoelectric cooling device 220 to control the thermoelectric cooling device 220. The control circuit 230 includes a circuit board 232 held in the housing 110, such as in the secondary cavity 168. The control circuit 230 includes wires 234 coupled to the thermoelectric cooling device 220 and the circuit board 232. In an exemplary embodiment, the control circuit 230 receives a power supply 236 to power the thermoelectric cooling device 220. The power supply 236 may be provided from the first and second fixed contacts 120a, 120b. For example, the circuit board 232 is electrically coupled to the first and second fixed contacts 120a, 120b to draw power from the first and second fixed contacts 120a, 120b to operate the control circuit 230. Alternatively, the power supply 236 may be from another power supply.
The thermal pads 250 are set in the cover 104. The thermal pads 250 are manufactured from a thermally conductive material. For example, the thermal pads 250 may be metal blocks, such as aluminum blocks. Alternatively, the thermal pads 250 may be ceramic blocks or manufactured from other thermally conductive materials. The thermal pads 250 may be rectangular, such as having a size and shape that compliments the size and shape of the fixed contacts 120. The thermal pads 250 are exposed at the bottom 116 of the contactor 100, such as for connection to the mounting structure 102 or for exposure into the surrounding environment, such as to dissipate the heat into the air surrounding the contactor 100.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
This application claims priority to U.S. Provisional Application No. 63/158,916, filed 10 Mar. 2021, titled “CONTACTOR WITH HEAT TRANSFER DEVICE,” which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63158916 | Mar 2021 | US |
