System and method for thermal management of an electric machine using a refrigerant can

Abstract

The electric machine with the thermal management system includes a stator having a stator core and a rotor having a rotor core and movable relative to the stator. At least one of the stator or rotor has one or more windings. One or more refrigerant cans enclose one or more of the windings disposed on the at least one of the stator and rotor in an internal compartment of the refrigerant can. The internal compartment of the refrigerant can defines a refrigerant flow path through the one or more windings. The refrigerant can has a refrigerant inlet and a refrigerant outlet in fluid communication with the internal compartment of the refrigerant can. The internal compartment of the one or more refrigerant cans is fluidly isolated from the stator core and the rotor core.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Application No. 63 / 106,096 (title: "Motors Including Coolant Cans"), filed October 27, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Some electrical components of an electric machine increase in temperature during operation of the electric machine. While it is undesirable for some electrical components of the electric machine to increase in temperature during operation of some electric machines, it is desirable for some electrical components of the same electric machine to increase in temperature during operation. Conventional electric machine thermal management systems typically use a refrigerant liquid to cool components of the electric machine or the entire electric machine. Due to the dynamic operation of some electric machines, it may be difficult for such systems to directly cool specific components of the electric machine.

[0003] For example, some electric machines, such as electric motors and generators, have a fixed component, often referred to as a "stator," and a rotating component, often referred to as a "rotor." In an electric motor, current is converted into an electromagnetic field, which in turn generates a mechanical force or torque between the stator and rotor, which can be used to perform motion. Generators operate on similar principles to electric motors, but convert mechanical force into current. While primarily focused on rotational force or torque, the principles described herein are also applicable to linear motors. For example, some linear motors use a rotor as the fixed component and a stator as the linear component.

[0004] In particular, in electric motors, the temperature of the windings or conductive elements located on or within the stator and / or rotor of the electric machine increases during continuous operation of the electric machine. Thermal management of the windings or conductive elements is particularly important in electric motors because as the temperature of the windings or conductive elements increases, the output performance of the electric motor decreases. Therefore, during operation, a coolant liquid is often circulated through the motor to cool the windings or conductive elements located on and / or within the stator and / or rotor of the electric machine. Unfortunately, conventional thermal management systems and methods for such electric machines can be inefficient or can result in additional performance losses for other components of the electric machine. Therefore, improved thermal management systems and methods for electric machines are needed to improve the performance of electric machines and motor assemblies. Summary of the Invention

[0005] The present disclosure provides a system and method for thermal management of an electric machine using a refrigerant can.

[0006] In some aspects of the present disclosure, an electric machine with a thermal management system includes a stator having a stator core, and a rotor having a rotor core and movable relative to the stator. At least one of the stator or the rotor of the electric machine has one or more windings. One or more refrigerant cans encapsulate the one or more windings of the at least one of the stator or the rotor in an internal compartment of the refrigerant can, the internal compartment defining a refrigerant flow path through the one or more windings. The refrigerant can has a refrigerant inlet and a refrigerant outlet in fluid communication with the internal compartment, and the internal compartment of the refrigerant can is fluidly isolated from the stator core and the rotor core.

[0007] In another aspect of the present disclosure, an electric machine with a thermal management system includes a stator having a stator core, a rotor having a rotor core and movable relative to the stator, a coolant pump, and a controller electrically connected to the coolant pump and configured to control the coolant pump. At least one of the stator or the rotor of the electric machine includes one or more windings. One or more coolant cans enclose one or more of the windings disposed on or within the at least one of the stator or the rotor in an internal compartment, the internal compartment defining a coolant flow path through the one or more windings. The coolant can has a coolant inlet and a coolant outlet in fluid communication with the internal compartment, and the coolant pump is in fluid communication with the one or more coolant inlets of the one or more refrigerant cans.

[0008] In yet another aspect of the present disclosure, a method for thermally managing an electric machine having a thermal management system includes flowing a coolant through an internal compartment of one or more coolant cans enclosing one or more windings of the electric machine within the internal compartment of the coolant can, the internal compartment of the coolant can being fluidly isolated from other components of the electric machine.

[0009] These and other aspects and advantages of the present disclosure will become apparent from the following description. In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which preferred configurations of the present disclosure are illustrated. However, such configurations are not necessarily representative of the entire scope of the present disclosure, and the appended claims should be used as a guide in interpreting the scope of the present disclosure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of an example electric drive system including an electric motor. [Figure 2] FIG. 1 is a front isometric view of a stator of an example electric motor of the present disclosure. [Figure 3]FIG. 3 is a rear isometric view of the stator of FIG. 2. [Figure 4] FIG. 3 is a front view of the stator of FIG. 2. [Figure 5] FIG. 3 is a rear view of the stator of FIG. 2. [Figure 6] FIG. 3 is a side view of the stator of FIG. 2. [Figure 7] FIG. 3 is a perspective view of a winding of an example of the stator of FIG. 2. [Figure 8] 8 is a perspective view of a refrigerant can of an example of the stator of FIG. 2, in which the winding of FIG. 7 is arranged inside the refrigerant can, and the lid of the refrigerant can is in a disassembled state. [Figure 9] 9 is a perspective view showing the assembled state of the refrigerant canister of FIG. 8 and an example of a stator tooth of the stator of FIG. 2. FIG. [Figure 10] 10 is a perspective view of the refrigerant can of FIG. 9 fitted onto the stator teeth, with the gap piece inserted. FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. [Figure 12] FIG. 12 is a partial cross-sectional view taken along line 12-12 of FIG. 2. [Figure 13] FIG. 10 is a front isometric view of a stator of another example electric motor of the present disclosure. [Figure 14] FIG. 14 is a front view of the stator of FIG. 13. [Figure 15] FIG. 14 is a side view of the stator of FIG. 13. [Figure 16] FIG. 14 is a perspective view of a refrigerant can frame of the stator core of the stator of FIG. 13. [Figure 17] FIG. 14 is an isometric view of the laminations of the stator core of the stator of FIG. 13. [Figure 18] FIG. 14 is an isometric view of the stator core of FIG. [Figure 19] 19 is a detailed view of detail 19-19 of FIG. 18, in which a gap piece is inserted into the gap of the stator core. [Figure 20] FIG. 20 is an isometric view of the example gap piece of FIG. 19. [Figure 21] FIG. 14 is an isometric view of the stator of FIG. 13 with the end cap pieces removed. [Figure 22] FIG. 22 is a cross-sectional view taken along line 22-22 of FIG. [Figure 23] FIG. 23 is a cross-sectional view taken along line 23-23 of FIG. 15. [Figure 24] FIG. 10 is a front isometric view of a stator of another example electric motor of the present disclosure. [Figure 25] FIG. 25 is a front view of the stator of FIG. 24. [Figure 26] FIG. 25 is a rear view of the stator of FIG. 24. [Figure 27] FIG. 25 is a side view of the stator of FIG. 24. [Figure 28] FIG. 25 is a perspective view of a refrigerant can of an example of the stator of FIG. 24. [Figure 29] FIG. 29 is an exploded view of the refrigerant canister of FIG. 28. [Figure 30] FIG. 29 is a perspective view of the refrigerant can of FIG. 28 positioned on a stator tooth. [Figure 31] FIG. 32 is a front perspective view of the refrigerant canister of FIG. 31. [Figure 32] 32 is a cross-sectional view taken along line 32-32 in FIG. 31. [Figure 33] FIG. 10 is a front isometric view of a stator of another example electric motor of the present disclosure. [Figure 34] FIG. 34 is a front view of the stator of FIG. 33. [Figure 35] FIG. 34 is a rear view of the stator of FIG. 33. [Figure 36] FIG. 34 is a side view of the stator of FIG. 33. [Figure 37] FIG. 34 is a rear perspective view of a refrigerant can of the example stator of FIG. 33. [Figure 38] FIG. 38 is an exploded view of the refrigerant canister of FIG. 37. [Figure 39] FIG. 38 is a perspective view of the refrigerant can of FIG. 37 positioned on a stator tooth. [Figure 40] FIG. 40 is a front perspective view of the refrigerant canister of FIG. 39. [Figure 41] 41 is a cross-sectional view taken along line 41-41 in FIG. 40. [Figure 42] FIG. 1 is a front isometric view of a rotor of an example electric motor of the present disclosure. [Figure 43]FIG. 43 is a side view of the rotor of FIG. 42. [Figure 44] FIG. 43 is a front view of the rotor of FIG. 42. [Figure 45] FIG. 43 is a rear view of the rotor of FIG. 42. [Figure 46] FIG. 43 is an exploded view of the rotor of FIG. 42. [Figure 47] FIG. 43 is an exploded view of the refrigerant can of the rotor of FIG. 42. [Figure 48] FIG. 43 is an exploded view of the refrigerant can and rotor poles of the rotor of FIG. 42. [Figure 49] FIG. 43 is an exploded view of the rotor shaft of FIG. 42. [Figure 50] FIG. 43 is an exploded view of the end cap of the rotor of FIG. 42. [Figure 51] FIG. 41 is a cross-sectional view taken along line 51-51 of FIG. 42. [Figure 52] FIG. 42 is a cross-sectional view taken along line 52-52 of FIG. [Figure 53] FIG. 43 is a cross-sectional view taken along line 53-53 of FIG. 42. [Figure 54] 41 is a cross-sectional view taken along line 51-51 in FIG. 42, showing a shaft portion of another example of a rotor disclosed herein. [Figure 55] FIG. 1 is a perspective view of an example winding with electrical components of an electric motor of the present disclosure. [Figure 56] FIG. 2 is a detailed view of the interior surface of an example refrigerant can of the present disclosure. [Figure 57] FIG. 1 is a schematic diagram of an example temperature control module for an electric machine. [Figure 58] 1 is a schematic diagram of various components of an example refrigerant flow system including a refrigerant manifold of an electric machine. DETAILED DESCRIPTION OF THE INVENTION

[0011] As detailed above, some electric machines may require thermal management systems, including cooling and thermal management systems, during operation to maintain the performance and extend the life of the electric machine. The present disclosure relates to thermal management systems for electric machines, such as electric motors with an electromagnetically coupled rotor and stator. In an electric motor, one or both of the stator and rotor include windings of electrical wire or conductive elements that can provide electromagnetic coupling by passing electrical current through the windings. This current causes heat dissipation in the windings, which can adversely affect the performance and life of the electric motor. For example, high temperatures can mechanically damage the conductors or associated components of the electric motor, or the electrical resistance of the conductors can increase as the windings heat up, reducing their performance.

[0012] Liquid coolants can be used to maintain the temperature of the windings of an electric machine, such as the windings of an electric motor, at an acceptably low temperature. Conventional cooling methods for electric motors include, for example, forced air cooling, spray cooling, and immersion cooling. Forced air cooling involves forcing air through the motor assembly to cool the motor's windings or conductive elements. Spray cooling systems can involve directing jets of coolant at specific motor components. Immersion cooling systems involve immersing the entire motor assembly in a liquid-containing volume during operation. Of these conventional cooling systems, immersion cooling is the most effective at cooling windings; however, both of these cooling systems result in a significant amount of coolant in the operating volume of the electric motor, which can cause one or both of at least two undesirable effects.

[0013] The first undesirable effect is increased windage or drag losses when the motor's moving parts come into contact with the coolant, particularly when the coolant is present in the motor's air gap (i.e., the gap between the stator and rotor), a common consequence of immersion cooling. While spray cooling can mitigate this adverse effect, it results in reduced cooling effectiveness compared to immersion cooling. Furthermore, spray cooling typically has significantly more interaction with other motor components due to both the proximity of the stator and rotor bodies within the working volume of the motor assembly and operational phenomena. Forced-air cooling also suffers from windage or drag losses, particularly when the high airflow required to achieve advanced cooling capacities or high power density electric machine designs is required.

[0014] Second, as noted above, in conventional electric motor designs, it is advantageous to maintain the temperature of the windings at a lower temperature than the stator or rotor core in which the windings are located. Immersion cooling, which involves the presence of a significant amount of coolant within the motor's operating volume, applies cooling indiscriminately to the windings, stator core, and rotor core, so that when the windings are cooled, the stator and rotor cores are cooled as well. Similarly, spray cooling can result in the unintended cooling of the stator and rotor cores when the sprayed coolant flows from the windings and disperses within the motor's operating volume, including the stator and rotor cores.

[0015] Furthermore, because the resistance of winding conductors is proportional to operating temperature, many conductive elements, such as, but not limited to, copper, are most efficient when kept as cool as possible, whereas other materials used in motors, such as, but not limited to, steel laminates, may benefit from higher operating temperatures, e.g., to minimize losses in the other materials under such conditions. Thus, direct cooling of some components in an electric machine is not always advantageous or desirable, and direct cooling may be incompatible with the needs of a particular electric machine. Other components, such as magnets, semiconductors, or even the stator or rotor, may require different thermal capabilities and operating conditions, further increasing the need for thermal management of the electric machine.

[0016] Additionally, many traditional electric motors and motor assemblies use passive or active heat jackets that function to remove heat from the conductive elements of the electric machine through the electric machine core, magnetic elements, or housing. Specifically, heat flow in electric machines and electromechanical assemblies is designed through the magnetic components, which creates a thermal gradient where the temperature of the conductors is higher than the temperature of the core. This, as noted above, can be detrimental to the performance of the core and / or the electric machine itself.

[0017] Recognizing the above drawbacks, in an effort to improve the performance of electric machines having windings or conductive elements, the present disclosure provides a thermal management system and method for providing cooling to the windings or conductive elements separately from the operating volume, including the internal components of the electric machine. For example, the electric machine described in this disclosure includes a coolant can encapsulating the windings or conductive elements, with the coolant flowing through the can and contacting only the windings or conductive elements of the stator or rotor, or both. In operation, the coolant can provides the efficiency benefits of immersion cooling while effectively providing cooling only to the windings or conductive elements. The coolant can fluidly isolates the coolant from other internal components of the electric machine, such as the stator core or rotor core of an electric motor to which the windings or conductive elements are attached or in electrical communication with, allowing the stator core or rotor core to maintain a relatively higher temperature than the enclosed windings or conductive elements. The present disclosure may enable the stator core and / or rotor core to be maintained at a higher temperature during motor operation than the windings or conductive elements disposed thereon, which represents a breakthrough over conventional motor internal processes.

[0018] As described above, in an electric motor, fluid isolation of the coolant in the windings or conductive elements from the stator or rotor core can improve motor performance. Unlike motor windings, which typically decrease in efficiency with increasing temperature (e.g., due to increased resistance), stator and rotor cores often exhibit increased efficiency with increasing temperature because eddy currents induced in the stator and rotor cores decrease with increasing temperature. The induced eddy currents act to heat the stator and rotor cores without relying on any heat transfer from the windings. By providing a coolant can in the thermal management system disclosed herein, a relatively high temperature can be maintained in the stator or rotor core, thereby simultaneously improving winding efficiency and housing / core efficiency. As used herein, "performance" of an electric machine refers to the power density, thermal headroom, and / or efficiency of the electric machine.

[0019] As described below, the present disclosure provides systems and methods for a thermal management system for an electric machine using a refrigerant can configured to provide direct cooling to the windings or conductive elements of the electric machine. In one non-limiting example, an electric motor includes a refrigerant can encapsulating windings or conductive elements disposed on or within a stator of the motor. Alternatively, or in addition, an electric motor or electric motor assembly includes a refrigerant can encapsulating windings or conductive elements disposed on or within a rotor of the motor. Alternatively, or in addition, an electric motor or electric motor assembly includes a refrigerant can encapsulating windings or conductive elements disposed on or within both a stator and a rotor of the motor. Additionally or alternatively, an electric motor or electric motor assembly includes a refrigerant can encapsulating windings or conductive elements in electrical communication with either or both of the stator or rotor. Also provided are systems and methods for monitoring and / or regulating coolant flow and temperature in an electric motor or electric motor assembly including a refrigerant can-based thermal management system.

[0020] While the following description applies the present disclosure to electric machines having a stator and / or rotor, the present disclosure is not intended to be limited to such electric machines. In some embodiments, the thermal management systems and methods, including refrigerant cans, can be applied to other electric machines having windings or conductive elements, such as electric transformers and electric inverters. In various embodiments, the thermal management systems and methods can be applied to electrical generators, combinations of electrical (or electromagnetic) systems, and mechanical and / or electrical power conversion devices that vary the flow of energy and mechanical or electrical pressure from an input to a desired output.

[0021] In some embodiments, the thermal management systems and methods comprising the refrigerant cans described below can be used to provide refrigeration or thermal control to electrical components or environments other than the windings or conductive elements of an electric machine. For example, in some embodiments, a transformer of an electric machine can be encapsulated in one or more refrigerant cans disclosed herein. In some embodiments, an inverter of an electric machine or electrical system can be encapsulated in one or more refrigerant cans disclosed herein.

[0022] Throughout this disclosure, the terms winding and conductor / conductive element may be used interchangeably, including bars, printed circuit boards (PCBs), semiconductors, Litz wire, multi-turn coils, cast or solid conductors, carbon nanotubes, and any other element capable of conducting electricity in an electrical circuit.

[0023] 1 is a schematic diagram of an electric drive system 100 including an electric motor 102 and a motor controller 104 coupled to the electric motor 102. The motor controller 104 is configured to operate the electric motor 102 to drive a load 106. The load 106 may be, for example, an additional gear train such as a gear set, vehicle wheels, a pump, a compressor, or another motor, in which case multiple motors may be coupled to operate in parallel.

[0024] The electric motor 102 has an output shaft 108 that is rotatable relative to a motor housing 110. The motor housing 110 serves as a datum for rotation and other motion of the motor components. In use, the output shaft 108 can be coupled to a load 106, and the electric motor 102 can provide a rotational force to the load 106 when electrically activated by appropriate power and signals from a motor control 104. In some embodiments, the output shaft 108 extends through the electric motor 102, exposing both ends of the output shaft 108. This allows rotational force to be output at both ends of the motor 102. While the motor housing 110 can be symmetrical about the axis of rotation of the output shaft 108, the motor housing 110 can have any outer shape and generally includes means for securing the motor housing 110 to another structure to prevent rotation of the housing 110 during operation of the motor 102.

[0025] The electric motor 102 can include an active magnetic element 112, such as a stator, and a passive magnetic element 114, such as a rotor. In some embodiments, the rotor can be the active component, for example, if the rotor includes a conductor or conductive element driven by an inverter or controllable power source. The stator, rotor, or both can include electrical circuitry that is controlled to generate an electromagnetic field relative to its opposing component, thereby producing a mechanical force between the components. For purposes of this description, the stator will be used as a representative example of the active magnetic element 112 and the rotor will be used as a representative example of the passive magnetic element 114 in the embodiments detailed below. In other embodiments, the active magnetic element 112 and the passive magnetic element 114 can be other components of other electric machines or motors.

[0026] The electric motor 102 can also be described as having at least two magnetic elements 112, typically a fixed element or stator and a freely movable element, such as a rotating element or rotor. The stator and / or rotor contain electrical circuitry that is controlled to generate an electromagnetic field relative to its opposing component, thereby producing a mechanical force between the components. For purposes of this detailed description, the present embodiment uses the stator as a representative example of the fixed magnetic element 112 and the rotor as a representative example of the movable magnetic element 114. In other embodiments, the fixed magnetic element 112 and the movable magnetic element 114 can be other components of other electric machines or motors. The rotor 114 is configured to electromagnetically interact with the stator 112 and can be disposed within the stator 112, such as in an inner rotor radial gap motor, or parallel to the stator 112, such as in an axial gap motor or linear motor, or external to the stator 112, such as in an outer rotor radial gap motor, or some combination of these arrangements. Electrical activity in the stator 112 drives the movement of the rotor 114. The rotor 114 is rotationally coupled to the output shaft 108 such that any rotation of the rotor is transmitted to and rotates the output shaft 108. The stator 112 is fixed in the electric motor 102 so that the rotor 114 moves around or parallel to the stator 112 during operation.

[0027] Passing a current through a loop of wire or conductive element creates a magnetomotive force (MMF) through the wound or surrounding area of ​​the wire or conductive element, creating a motor pole. In a typical electric motor, such a loop must have a diameter sufficient to carry the desired current load, which in some embodiments must be thin enough so that the skin depth at the driving frequency penetrates completely through the loop. In some embodiments, the magnetic field strength of the pole is increased by using more turns or more overlapping loops of wire. This topology may be referred to as a wound field pole. The above set of overlapping loops is referred to as a coil.

[0028] In this disclosure, a "winding" refers to a coil of wire or conductive element configured to work with other coils or conductive elements of an electric machine, such as the stator or rotor of an electric motor. In practice, windings can take a variety of forms. For example, in some cases, coils of wire are wound together in series, so that each turn of the coil has the same magnetic axis. Such series-wound coils, or coils wound on separate rotor or stator teeth, may be referred to as "concentrated windings." In some cases, a coil may overlap and surround multiple rotor or stator teeth. Such overlapping coils may be referred to as an armature or "distributed winding." One magnetic pole is the magnetic center of this distributed winding, allowing it to move relative to the individual coils in the distributed winding in response to drive current passing through the winding. In some cases, a coil may be wound around a yoke or yoke from a tooth slot on either the rotor or stator. Such a coil may be referred to as a "toroidal winding."

[0029] 1, the stator 112 has a plurality of stator poles, and the rotor 114 has a plurality of rotor poles, with electrical windings provided about the stator. The rotor 114 mates with the stator 112 to define a nominal air gap between the stator and rotor, e.g., in some embodiments, the nominal air gap is defined between the rotor teeth and the stator teeth. The rotor 114 is movable relative to the stator 112, e.g., rotatable about an axis of rotation or linearly movable in one or more defined directions.

[0030] 2-6 illustrate a non-limiting example of a stator 200 according to one embodiment of the present disclosure. The stator 200 includes a generally cylindrical stator core 202 and a plurality of refrigerant cans 204 circumferentially arranged around the stator core 202. The stator core 202 has an inner circumferential surface 206 having an inner diameter 208 and defining an opening 210. The opening 210 is configured to receive a rotor (not shown) of an electric motor such that an air gap exists between the rotor and the inner circumferential surface 206. The stator core 202 has a longitudinal axis 212 extending through the opening 210.

[0031] A plurality of stator teeth 214 extend radially from the stator core 202 and are oriented circumferentially about the stator core 202. An outer diameter 220 of the stator core 202 is defined by outer ends 218 of the plurality of stator teeth 214. Each of the plurality of stator teeth 214 is configured to receive the openings of a plurality of refrigerant cans 204 (see FIGS. 11 and 12). In this embodiment, the stator teeth 214 are circumferentially spaced apart to receive every other refrigerant can 204 (see FIG. 12).

[0032] In some embodiments, stator core 202 (including stator teeth 214) is made of a magnetically permeable material, such as iron. In some embodiments, stator core 202 is made of one or more cylindrical sections with stator teeth formed on its outer surface. In some embodiments, stator core 202 is made of multiple stator plates or laminations, which reduces eddy currents in the magnetically permeable material of stator core 202. For example, in some embodiments, stator laminations are included on the outer surface of stator core 202.

[0033] In some embodiments, stator core 202 includes other elements in addition to a magnetically permeable material. For example, in some embodiments, stator core 202 includes an adhesive and / or an electrically insulating material (e.g., a varnish and / or a metal oxide). In some embodiments, portions of the stator core include or are encapsulated in an epoxy or other insulating material.

[0034] 7-12 show the refrigerant can 204 in more detail. The refrigerant can 204 has a body 230 that defines an interior compartment 232 of the refrigerant can 204. A rear wall 234 of the body 230 defines one or more inlets 236 that are in fluid communication with the interior compartment 232 of the body 230 of the refrigerant can 204. A front wall 238 of the body 230 defines one or more outlets 240 (shown in FIGS. 2 and 4) that are in fluid communication with the interior compartment 232 of the body 230 of the refrigerant can 204. An interior wall 242 of the body 230 is disposed within the interior compartment 232, and the interior wall 242 defines an opening 244 that extends through a bottom wall 246 and a top wall 248 of the body 230.

[0035] Referring to FIG. 8 , concentrated windings 250 are disposed within the internal compartment 232 and are wound around the interior wall 242 of the body 230 (see FIG. 11 ). In this embodiment, the top wall 248 of the body 230 comprises a lid 252 that is removable from the body 230 such that the internal compartment 232 of the body 230 is accessible when the lid 252 is removed. In some embodiments, the bottom wall 246 of the body 230 is removable. After the windings 250 are disposed within the body 230 of the refrigerant can 204, the lid 252 can be joined to the body 230 by one or more of a variety of techniques, including ultrasonic welding, adhesives, and mating clips. The techniques described above for joining portions of the refrigerant can 204 can also be used to join portions of the other example refrigerant cans described herein. In some embodiments, a sealing member, such as a gasket, may be disposed between the lid 252 and the body 230 to provide a fluid seal between the lid 252 and the body 230 of the refrigerant canister 204 .

[0036] 8-10, the body 230 of the refrigerant can 204 is configured to enclose the winding 250 within the interior compartment 232 of the body 230. In this embodiment, the winding 250 is wound in a generally rectangular shape that tapers downwardly so that the winding 250 fits within the interior compartment 232 and fits around the cylindrical interior wall 242 of the body 230 (see FIGS. 7 and 9). In some embodiments, the winding 250 is wound in a cylindrical shape. In some embodiments, the winding 250 is wound to fit into two or more openings 244 in the body 230 of the refrigerant can 204.

[0037] In some embodiments, winding 250 comprises elements other than wires. For example, in various embodiments, winding 250 comprises an adhesive or binder structure that holds together the multiple strands of wires in winding 250 and / or a potting material, such as a thermoplastic resin, that fills the spaces between the individual wires in winding 250.

[0038] Some electric machines require electrical isolation to prevent unwanted electrical conduction in the electric machine or to prevent the conduction of currents that are undesirable to the performance, safety, or lifespan of the system. For example, electric motors require insulation between conductive and magnetic elements (see FIG. 1). In conventionally configured motors, this insulation serves no other function than electrical isolation and, in certain embodiments, may inhibit or limit the heat flow necessary to cool the conductive elements. As discussed throughout this disclosure, a refrigerant can provide electrical insulation and thermal management for the system in this disclosure. For example, a refrigerant provides electrical isolation in addition to fluid isolation to direct and control heat flow among system components.

[0039] Thus, in some embodiments, winding 250 includes one or more insulating layers that surround the wires or conductive elements of the winding within interior compartment 232 of refrigerant can 204, thereby electrically insulating winding 250 from other components of stator 200, other components of the electric machine, and / or machinery or mechanical components external to the electric machine while winding 250 is cooled by refrigerant flowing within refrigerant can 232. Insulating materials may include paper, plastic, varnish, rubber, or potting material that comprises part or all of the refrigerant can structure (see FIGS. 11 and 12).

[0040] Figure 11 is a cross-sectional view of a portion of a refrigerant can 204 taken along line 11-11 in Figure 10. As can be seen in Figure 11, the refrigerant can 204 is disposed on a stator tooth 214 of the stator core 202, with the stator windings 250 surrounding the stator tooth 214 via the inner wall 242 of the body 230 of the refrigerant can 204. In the illustrated embodiment, each refrigerant can 204 encloses one winding 250 and one stator tooth 214. In other embodiments, each refrigerant can 204 can enclose two or more windings 250 and surround two or more stator teeth 214.

[0041] The body 230 defines a fluid flow path through the interior compartment 232 of the refrigerant can 204 such that refrigerant enters the interior compartment 232 of the body 230 through one or more inlet ports 236, passes through gaps in the stator windings 250 (see FIG. 12 ), and exits the interior compartment 232 through one or more outlet ports 240 in the body 230. In this embodiment, the refrigerant can 204 is fluidly isolated from the stator core 202, so that refrigerant flowing through the body 230 of the refrigerant can 204 contacts the windings 250 but does not contact the stator teeth 214 or the outer surface 216 of the stator core 202.

[0042] The cooling efficiency of the windings 250 enclosed in the refrigerant can 204 may depend on the volume of the internal compartment 232 of the refrigerant can 204 and the volume of the windings 250 disposed within the internal compartment. The larger the volume of the windings 250, the less volume of refrigerant that can flow within the internal compartment 232. In some embodiments, the ratio of the volume of the internal compartment of the refrigerant can to the volume of the one or more windings disposed within the internal compartment is between 100:95 and 100:75. In some embodiments, the ratio of the volume of the internal compartment of the refrigerant can to the volume of the one or more windings disposed within the internal compartment is between 10:9 and 10:7. In some embodiments, the ratio of the volume of the internal compartment of the refrigerant can to the volume of the one or more windings disposed within the internal compartment is between 5:4 and 2:1. In some embodiments, the ratio of the volume of the internal compartment of the refrigerant can to the volume of the windings is between 5:3 and 10:3.

[0043] In some embodiments, the effectiveness of cooling of conductive elements can be described by the fluid thickness established within the coolant can. Traditional thinking has been that the relative volume of fluid to conductors should be large to adequately sink and / or remove the heat required during operation. However, performance can be improved by reducing the fluid thickness, or by reducing the fluid volume relative to the conductor volume. In some embodiments, the fluid thickness within the interior compartment 232 of the coolant can 204 ranges from approximately 0.2 mm to 0.7 mm. In some embodiments, the fluid thickness within the interior compartment 232 of the coolant can 204 ranges from approximately 0.5 mm to 1.5 mm. In some embodiments, the fluid thickness within the interior compartment 232 of the coolant can 204 ranges from approximately 1 mm to 3 mm. Interestingly, the clearance required to minimize peak coil temperature may not be the same as the clearance required to minimize Joule heating losses, which may benefit from the smallest possible clearance. Some applications (e.g., high power density applications) may benefit from reduced peak temperatures. In other applications, it may be advantageous to reduce Joule heating losses (eg, high efficiency applications).

[0044] In some embodiments, the interior compartment 232 of the refrigerant can 204 is not completely sealed from other components of the electric motor. For example, in some embodiments, portions of two or more refrigerant cans 204 are in fluid communication with one another, forming a partial seal between the interior compartments 232 of the two or more refrigerant cans 204. In some embodiments, the refrigerant can 204 may have one or more inlets 236 and outlets 240, as well as openings formed in the body 230 of the refrigerant can, which allow refrigerant to exit the refrigerant can 204 and contact other components of the electric motor. For example, the bottom wall 246 of the body 230 of the refrigerant can 204 may be formed with one or more holes to allow a volume of refrigerant to leak through the one or more holes and contact the stator core 202 or rotor of the electric motor as the refrigerant flows through the interior compartment 232.

[0045] For example, in some embodiments, less than 5% of the total volume of refrigerant entering the internal compartment 232 can escape from the refrigerant can 204 through a path other than one or more outlets 240 of the refrigerant can 204. In some embodiments, less than 3% of the total volume of refrigerant entering the internal compartment 232 can escape from the refrigerant can 204 through a path other than one or more outlets 240 of the refrigerant can 204. In some embodiments, less than 1% of the total volume of refrigerant entering the internal compartment 232 can escape from the refrigerant can 204 through a path other than one or more outlets 240 of the refrigerant can 204.

[0046] In some embodiments of the present disclosure, where the refrigerant can is configured to encourage small amounts of refrigerant to flow out of the refrigerant can as described above, the refrigerant can is still "fluidically isolated" from the stator core or rotor as defined in the present disclosure.

[0047] 2-6, in this embodiment, the plurality of refrigerant cans 204 are oriented in the circumferential direction of each stator tooth 214 of the stator core 202. In this embodiment, a plurality of first stator teeth 260 of the stator teeth 214 receive the refrigerant cans 204, and the plurality of first stator teeth 260 are thereby surrounded by the concentrated windings 250 enclosed in the refrigerant cans 204. In this manner, each of the plurality of first stator teeth 260 corresponds to a respective magnetic pole generated by the current passing through the stator windings 250. Each of the plurality of second stator teeth 262 of the stator teeth 214 is disposed between two refrigerant cans 204. This configuration reduces the amount of material, including the body 230 of the refrigerant can 204, between the stator teeth 214 (i.e., in the "slots" between the stator teeth 214), thereby maximizing the winding space factor between the stator teeth 214. In various embodiments, less than about 25% of the slots are filled with refrigerant can material, less than about 15% of the slots are filled with refrigerant can material, or less than about 5% of the slots are filled with refrigerant can material.

[0048] Unlike traditional designs that attempt to use all of the available area for windings in the slots to maintain high performance, the coolant can allows for a reduction in the slot conductor space factor while still providing high performance operation or improving performance. This allows for an increase in the current density of the conductors in the electric machine, which is typically associated with lower performance, while still providing the performance improvements described throughout this application. In other applications, such as high torque density applications, the coolant can allows for an increase in magnetic core material compared to the required slot area of ​​a traditional electric machine, which, for the same magnetomotive force, allows for lower saturation of the electric machine and higher saturation levels of the electric machine for improved electromagnetic performance.

[0049] Thus, in some embodiments, the stator core 202 is configured such that each stator tooth 214 receives a respective refrigerant can 204, and thus each stator tooth 214 is surrounded by one or more windings 250 enclosed in the refrigerant can 204. In such embodiments, two or more circumferentially adjacent refrigerant cans 204 may share the same wall between the bodies 230 of the refrigerant cans 204. In some embodiments, one stator tooth 214 is surrounded by multiple windings 250. In some embodiments, one refrigerant can 204 is disposed across and received by multiple stator teeth 214.

[0050] Referring again to FIG. 10, in this embodiment, when one of the multiple refrigerant cans 204 is placed on the stator tooth 214, the top 270 of the stator tooth 214 extends through the opening 244 in the body 230 and above the upper wall 248 of the body 230 of the refrigerant can 204.

[0051] FIG. 12 is a cross-sectional view of multiple refrigerant cans 204 arranged around the circumference of stator core 202, taken along line 12-12 in FIG. 2. As can be seen in FIG. 12 , when refrigerant can 204 is fitted onto one of multiple first stator teeth 260, refrigerant can 204 contacts one of multiple second stator teeth 262 on both sides, forming a gap between the apexes 270 of stator teeth 214. By inserting a gap piece 272 between the two apexes 270 of stator teeth 214, a substantially continuous outer surface of stator 200 can be formed. In some embodiments, gap piece 272 is made of the same material as stator core 202. In some embodiments, gap piece 272 is made of a different material than stator core 202. In some embodiments, the radial height of multiple first stator teeth 260 and the radial height of multiple second stator teeth 262 are not equal, and therefore gap piece 272 is not necessary.

[0052] As mentioned above, in some electric machines, it may be advantageous to provide windings having coils that overlap and surround multiple teeth on either the rotor or the stator, i.e., distributed windings. Some stators or rotors disclosed herein include distributed windings. In such embodiments, because each winding is distributed over most or all of the circumference of the stator or rotor and is intertwined between multiple teeth, the coolant cans that define the coolant flow passages corresponding to the distributed windings in a stator or rotor with distributed windings may have a different structure than the coolant cans described for concentrated windings.

[0053] Furthermore, some electric machines may have windings with coils wound around one of the yokes in one of the tooth slots of the rotor or stator, i.e., toroidal windings. Some stators or rotors disclosed herein have toroidal windings (see FIGS. 24-41). In such embodiments, because each winding is distributed around the yoke across multiple axial components of the motor, the coolant can defining the coolant flow passages corresponding to the toroidal windings in a stator or rotor having a toroidal winding may have a different structure than the coolant can described for concentrated windings. It may have a configuration similar to either a concentrated winding or a distributed winding, or a combination thereof.

[0054] 13-23 illustrate an example stator having a thermal management system with a refrigerant can for distributed windings according to the present disclosure. The refrigerant cans configured for the distributed windings of this embodiment share a common configuration with the refrigerant cans configured for concentrated windings described with reference to FIGS. 2-12. However, in this embodiment, the windings are interconnected through each stator refrigerant can, and therefore the stator refrigerant cans are not configured to be fluidly isolated from each other.

[0055] 13-15, an example stator 300 includes a stator core 302, a first end cap 304, and a second end cap 306, with the first end cap 304 disposed at a first axial end 308 of the stator core 302 and the second end cap 306 disposed at a second axial end 310 of the stator core 302. Similar to the example embodiment stator 200 described with reference to FIGS. 2-12, the stator 300 includes an opening 312 extending through both axial ends 308, 310 along a longitudinal axis 314 of the stator core 302 and configured to receive a rotor (not shown) of an electric motor. In this embodiment, the stator core 302 is configured to receive distributed stator windings (not shown) encased in a plurality of refrigerant can elements 350 (see FIGS. 22 and 23) disposed on the stator core 302.

[0056] 16-18, the stator core 302 is composed of a refrigerant can frame 324 and a stator core 326 disposed within the refrigerant can frame 324. The refrigerant can frame 324 has an opening that defines the opening 312 in the stator 300. The refrigerant can frame 324 includes a first end cap 330 disposed at the first axial end 308 of the stator core 302 and a second end cap 332 disposed at the second axial end 310. The outer diameter of the stator core 302 is defined by the outer diameter 336 (see FIG. 14) of the first end cap 330 and the second end cap 332 of the refrigerant can frame 324. The inner diameter 338 (see FIG. 14) of the end caps 330 and 332 is defined by the opening 312 in the stator 300. The first end cap 330 and the second end cap 332 have an inner wall 342 and an outer rim 344 and an inner rim 346 extending axially outward from the inner wall 342. The outer rim 344 has an outer diameter 336, and the inner rim 346 has an inner diameter 336. The outer rim 344 has an outer recessed edge 348 (see FIG. 19) formed on the end caps 330, 332 and extending toward the inner wall 342. The inner rim 346 has an inner recessed edge 352 (see FIG. 19) formed on the end caps 330, 332 and extending toward the inner wall 342 a distance equal to the distance the outer recessed edge 348 of the outer rim 344 extends toward the inner wall 342.

[0057] A plurality of refrigerant can elements 350 are circumferentially disposed between the inner rim 346 and outer rim 344 of the end caps 330, 332 and extend axially through the inner walls 342 of the end caps 330, 332 of the refrigerant can frame 324. The refrigerant can elements 350 face radially inward toward the longitudinal axis 314 of the stator 300, with the outer walls 354 of the refrigerant can elements 350 positioned radially within the outer diameters 336 of the end caps 330, 332. The refrigerant can elements 350 include a first sidewall 356 and a second sidewall 358 opposite the first sidewall 356. An air gap opening 360 (see FIG. 19 ) is disposed in each refrigerant can element 350 on the side opposite the outer wall 354 toward the longitudinal axis 314 of the stator 300. The air gap opening 360 extends axially through the inner rim 346 of the end caps 330, 332 and is defined by the walls 354, 356, 358 of the refrigerant can element 350. The walls 354, 356, 358 of the refrigerant can element 350 and the inner walls 342 of the end caps 330, 332 define a plurality of stator tooth openings 368, configured such that one stator tooth opening 368 is disposed adjacent to each side wall 356, 358 of the refrigerant can element 350.

[0058] 17 , the stator core 326 is shown in more detail. The stator core 326 has an opening 370 that extends axially through the longitudinal axis 314 of the stator 300. In this embodiment, the stator core 326 has an inner diameter 372 and an outer diameter 374 that extend axially through the longitudinal axis 314, where the inner diameter 372 is the same as the inner diameter 336 of the refrigerant-can frame 324 and the outer diameter 374 is the same as the outer diameter 338 of the refrigerant-can frame 324. The stator core 326 includes a plurality of stator teeth 376 circumferentially disposed about the inner diameter 372 of the stator core 326, and the stator teeth 376 extend axially through the axial ends of the stator core 326. In some embodiments, one or both of the inner diameter 372 and the outer diameter 374 of the stator core are different from the inner diameter 336 and the outer diameter 338 of the refrigerant-can frame 324.

[0059] In some embodiments, stator core 326 is made of a magnetically permeable material, such as iron. In some embodiments, stator core 326 includes stator laminations, which reduce eddy currents in the magnetically permeable material of stator core 326. In some embodiments, stator core 326 includes other elements in addition to the magnetically permeable material. For example, in some embodiments, stator core 326 includes an adhesive and / or an electrically insulating material (e.g., a varnish and / or a metal oxide). In some embodiments, portions of stator core 326 include or are encapsulated in an epoxy or other insulating material.

[0060] 18, a stator core 326 is disposed between end caps 330, 332 around the periphery of refrigerant-can frame 324. A plurality of stator teeth 376 are received in each stator tooth opening 368 of refrigerant-can frame 324. As shown in FIG. 18, when stator core 326 is placed over refrigerant-can frame 324, stator teeth 376 form a substantially continuous inner surface of opening 312 of stator 300. In this embodiment, stator teeth 376 are configured such that a portion of each tooth 376 contacts each wall 354, 356, 358 of refrigerant-can element 350 (see FIG. 23).

[0061] In some embodiments, refrigerant can frame 324 is constructed from a single piece. In such an embodiment, refrigerant can frame 324 can be overmolded within stator core 326. In some embodiments, refrigerant can frame 324 is constructed from two or more pieces joined within stator core 326. In such an embodiment, the two or more pieces or refrigerant can frame 324 can be joined by one or more of a variety of techniques, including ultrasonic welding, adhesives, and mating clips. The above techniques for joining pieces of refrigerant can frame 324 can also be used to join other components of the refrigerant can frame described herein.

[0062] 19 and 20, the internal structure of the stator core 302 is shown. FIG. 19 is a detailed view of the assembled refrigerant-can frame 324 and stator core 326. Because the distributed winding (not shown) extends between multiple refrigerant-can elements 350, the distributed winding is inserted into each refrigerant-can element 350 through the air gap opening 360 of the refrigerant-can element 350 and positioned adjacent to the inner wall 342 of the end caps 330 and 332. As shown in FIG. 19, after the distributed winding (not shown) is inserted, an air gap cap 380 is inserted into each air gap opening 360 of the refrigerant-can element 350. The air gap cap 380 is configured to provide a wall opposite the outer wall 354 of the refrigerant-can element 350 and has a recessed edge 382 formed to align with the inner recessed edge 352 of the inner rim 346 of the end caps 330 and 332. Thus, when the air gap cap 380 is inserted into the air gap opening 360, the walls 354, 356, 358 of the refrigerant can element 350 and the air gap cap 380 define an interior compartment 384 of the refrigerant can element 350. The interior compartment 384 of the refrigerant can element 350 has an inlet 386 and an outlet 388 defined by the interior walls 342 of the end caps 330, 332 (see FIGS. 21 and 22).

[0063] 20 , two end cap pieces 304, 306 are inserted into the inner rim 346 and outer rim 344 of the end caps 330, 332. In the illustrated embodiment, the inner surfaces of the end cap pieces 304, 306 contact both the outer recessed edge 348 of the outer rim 344 of the end caps 330, 332 and the inner recessed edge 352 of the inner rim 346 (including the recessed edge 382 of each air gap cap 380 inserted into the air gap opening 360), and the outer surfaces of the end cap pieces 304, 306 are flush with the outer rim 344 and inner rim 346 of the end caps 330, 332. In some embodiments, as described throughout this disclosure, the end cap pieces 304, 306 are bonded to the refrigerant can frame 324, such as by welding, adhesives, clips, or other known bonding means. In some embodiments, a sealing member, such as a gasket, is disposed between each end cap piece 304 , 306 and the refrigerant can frame 324 to provide a seal between the end cap pieces 304 , 306 and the refrigerant can frame 324 .

[0064] End cap pieces 304, 306 have a plurality of openings 390 circumferentially arranged around the end cap pieces. In some implementations, end cap pieces 304, 306 have the same number of openings 390. In some embodiments, first end cap piece 304 has more openings 390 than second end cap piece 306, or vice versa. In some embodiments, one of end cap pieces 304, 306 has no openings 390.

[0065] 21 and 22, when the first end cap piece 304 is received in the first end cap 330, the inner and outer rims 346, 344 and the interior wall 342 of the first end cap 330 define an interior compartment 392 of the first end cap 330. Similarly, when the second end cap piece 306 is received in the second end cap 332, the inner and outer rims 346, 344 and the interior wall 342 of the second end cap 332 define an interior compartment 394 of the second end cap 332. The openings 390 in the end cap pieces 304, 306 are in fluid communication with the interior compartments 392, 394 of the end caps 330, 332, respectively. The interior compartments 392, 394 of the end caps 330, 332 are in fluid communication with the respective interior compartments 384 of each refrigerant can element 350 at the inlet 386 and outlet 388 of that refrigerant can element 350. In this manner, the interior compartments 384 of each refrigerant can element 350 are in fluid communication with each of the other refrigerant can elements 350.

[0066] In some embodiments, some refrigerant can elements 350 may not be in fluid communication with some other refrigerant can elements 350. In some embodiments, some refrigerant can elements 350 are in fluid communication only with the interior compartment 392 of the first end cap 330, and some refrigerant can elements 350 are in fluid communication only with the interior compartment 394 of the second end cap 332.

[0067] 21 is a cross-sectional view of the refrigerant can element 350 taken along line 22-22 in FIG. 14. When refrigerant enters the internal compartment 392 of the first end cap 330 through one or more openings 390 in the first end cap piece 330, the refrigerant flows into the inlet 386 of each refrigerant can element 350, passes through the internal compartment 384 and a portion of the distributed winding (not shown), and flows toward the outlet 388 of each refrigerant can element 350. The refrigerant flows out of the refrigerant can element 350 through the outlet 388 of the refrigerant can element 350 and into the internal compartment 394 of the second end cap 332. The refrigerant then flows out of the internal compartment 394 of the second end cap 332 through one or more openings 390 in the second end cap piece 306.

[0068] In this embodiment, stator core 326 is fluidly isolated from the coolant flow through interior compartment 384 of coolant can element 350 of coolant can frame 324. Thus, stator core 326 can maintain a higher temperature during motor operation than conventional forced-air, spray, or immersion cooling techniques. In some embodiments, coolant can frame 324 is configured to supply coolant to stator core 326 through additional outlets located in interior compartment 384 of one or more coolant can elements 350 and / or interior compartments 392, 394 of end caps 330, 332.

[0069] In some embodiments, the thermal management system comprising the above-described coolant can for concentrated, distributed, or toroidal windings can be applied to either the stator or rotor, or both, of an electric machine. In some embodiments, the stator of an electric machine can have distributed windings and the rotor of the electric machine can have concentrated windings, or vice versa. In some embodiments, an electric machine can have concentrated or distributed windings on components other than the stator or rotor. In some embodiments, an electric machine other than an electric motor can have concentrated or distributed windings.

[0070] Some types of electric machines may require concentrated windings in a form different from the concentrated windings described with reference to FIGS. 2-12. For example, some electric machines have wire wound around multiple radial cross sections of a substantially toroidal component, i.e., toroidal concentrated windings. In some embodiments of the present disclosure, an electric machine, such as an electric motor, may have toroidal concentrated windings disposed on a substantially toroidal stator core and / or rotor core. In such embodiments, because the concentrated windings are distributed across the radial cross sections of the stator core and / or rotor core, the coolant can encapsulating the toroidal concentrated windings may have a different structure than the coolant cans configured to encapsulate the concentrated windings described with reference to FIGS. 2-12.

[0071] Figures 24-32 show an example stator having multiple toroidal concentrated windings. The refrigerant can configured for the toroidal concentrated windings of this example embodiment has a common configuration with the refrigerant can configured for the concentrated windings described with reference to Figures 2-12. However, the shape of the toroidal concentrated windings in this example embodiment is different from the shape of the concentrated windings 250 of Figures 2-12, and therefore the shape of the refrigerant can in this example embodiment is different from the shape of the refrigerant can 204 of the example embodiment of Figures 2-12.

[0072] 24-27, a stator 400 includes a stator core 402 and a plurality of coolant cans 404. The stator core 402 has an opening 406 through a longitudinal axis 408 of the stator 400. The coolant cans 404 are circumferentially disposed on the stator core 402 about the longitudinal axis 408 of the stator 400. In this embodiment, the coolant cans 404 are configured to enclose a toroidal concentrated winding 410 (see FIGS. 28 and 29) wrapped around a cross section of the stator core 402 at a radial angle 412 relative to the longitudinal axis 408 of the stator 400. In some embodiments, the radial angle 412 is less than 45 degrees. In some embodiments, the radial angle 412 is in the range of 1 to 10 degrees. In some embodiments, the radial angle 412 is in the range of 5 to 15 degrees. In some embodiments, the radial angle 412 is in the range of 20 to 35 degrees. In some embodiments, the radial angle 412 is in the range of 30 to 45 degrees.

[0073] 28 and 29, the refrigerant can 404 and the toroidal concentrated winding 410 are shown in more detail. FIG. 29 is an exploded view of the refrigerant can 404 having a first piece 420 and a second piece 422. Similar to the body 230 and lid 252 of the refrigerant can 204 of the example embodiment described in FIGS. 2-12, when the first and second pieces 420, 422 of the refrigerant can 404 are joined, the refrigerant can 404 defines an interior compartment 424 of the refrigerant can 404. In some embodiments, as described throughout this disclosure, the first and second pieces 420, 422 of the refrigerant can 404 are joined, for example, by welding, adhesive, clips, or other known joining means. In some embodiments, a sealing member, such as a gasket, is disposed between the first and second pieces 420, 422 of the refrigerant can 404 to provide a seal between the first and second pieces 420, 422 of the refrigerant can 404.

[0074] The interior compartment 424 of the refrigerant can 404 is configured to enclose the toroidal winding 410 so as to fluidly isolate the toroidal winding 410 from the stator core 402 and other components of the electric motor. The assembled refrigerant can 404 has an opening 430 extending through the first piece 420 and the second piece 422 and an interior wall 432 extending through the interior compartment 424 of the refrigerant can 404. The opening 430 in the refrigerant can 404 is configured to receive a stator segment 436 (see FIGS. 30-32) of the stator core 402. A refrigerant inlet 440 is disposed in a rear wall 442 of the refrigerant can 404 and is in fluid communication with the interior compartment 424 of the refrigerant can 404. A refrigerant outlet 444 is disposed in a front wall 446 (see FIG. 31) of the refrigerant can 404 and is in fluid communication with the interior compartment 424 of the refrigerant can 404.

[0075] For purposes of illustration, the toroidal winding 410 is shown in Figure 29 as a solid piece with one or more conductors 450 emerging from the toroidal winding 410. The interior compartment 424 of the refrigerant can 404 is configured to receive the toroidal winding 410 such that the toroidal winding 410 is wrapped around the interior wall 432 of the refrigerant can 404. In this embodiment, the inlet 440 of the refrigerant can 404 is configured to not only pass fluid into the interior compartment 424 of the refrigerant can 404 but also to receive the conductors 450 of the toroidal winding 410 emerging from the refrigerant can 404.

[0076] In some embodiments, the conductors 450 of each winding 410 are electrically connected to one or more other components of the thermal management system of the electric machine or components of other parts of the electric machine. For example, in some embodiments, the conductors 450 of each winding 410 are electrically connected to the conductors 450 of other windings 410, which may be enclosed in separate refrigerant cans. In some embodiments, the conductors 450 of each winding 410 are electrically connected to bus bars. In some embodiments, the conductors 450 of each winding 410 are electrically connected to active electrical circuitry.

[0077] The interior compartment 424 of the can 404 defines a fluid flow path such that when liquid coolant enters the interior compartment 424 of the can 404 through the inlet 440, the coolant passes through the toroidal windings 410 and exits the interior compartment 424 through the outlet 444 of the can 404. In this embodiment, the can 404 is fluidly isolated from the stator core 402, so that coolant flowing through the interior compartment 424 of the can 404 contacts the windings 410 but does not contact portions of the stator core 402.

[0078] 30-32, details of the refrigerant cans 404 disposed on the stator core 402 are shown. In this embodiment, the stator core 402 is comprised of multiple stator segments 454, each corresponding to a respective one of the multiple refrigerant cans 404. In this embodiment, the stator segments 454 are "T-shaped," with an upper portion 460 of the stator segment 454 extending perpendicularly to a lower portion 462. The upper portion 460 has first side teeth 464 and second side teeth 466 opposite the first side teeth 464. The upper portion 460 has an outer surface 468, a first inner side surface 470 of the first side teeth 464, and a second inner side surface 472 of the second side teeth 466. The lower portion 462 has a first side surface 474, a second side surface 476, and an inner surface 478. Each stator segment 454 is configured to receive the opening 430 of one of the refrigerant cans 404 such that the inner surface 434 contacts the top surface 468 , the first inner surface 470 , and the first side 474 of the stator segment 454 .

[0079] Furthermore, each stator segment 454 is fitted with two other stator segments 454 arranged adjacent to it in the circumferential direction, so that the assembled stator segments 454 form the stator core 402. In this embodiment, the stator segments 454 have a fitting groove 480 and a fitting recess 482. The stator 400 is assembled by fitting the fitting groove 480 of one stator segment 454 into the fitting recess 482 of the other stator segment 454. When the two stator segments 454, each with a refrigerant can 404 provided thereon, are fitted together, the refrigerant can 404 arranged on one stator segment 454 contacts the second inner side surface 472 and the second bottom side surface 476 of the other stator segment 454. The outer surfaces 468 of the stator segments 454 are configured to form a substantially continuous outer surface of the stator core 402 at the first diameter 490 (see FIG. 26 ) when the plurality of stator segments 454 are assembled together. The lower surfaces 478 of the stator segments 454 are similarly configured to form a substantially continuous inner surface of the stator core 402 at the second diameter 492 when the plurality of stator segments 454 are assembled together.

[0080] In some embodiments, the ratio of first diameter 490 to second diameter 492 of stator core 402 ranges from 10:9 to 3:2. In some embodiments, the ratio of first diameter 490 to second diameter 492 of stator core 402 ranges from 7:5 to 9:5. In some embodiments, the ratio of first diameter 490 to second diameter 492 of stator core 402 ranges from 13:10 to 2:1. In some embodiments, the ratio of first diameter 490 to second diameter 492 of stator core 402 ranges from 19:10 to 5:2.

[0081] In some embodiments, stator segments 454 comprising stator core 402 include the stator core materials and laminations described throughout this disclosure, such as the materials and laminations of stator core 326 of FIGS.

[0082] 33-41 show another example stator, which includes a plurality of example toroidal concentrated windings different from the example toroidal concentrated winding 410 described with reference to FIGS. 24-32. The refrigerant can configured for the toroidal concentrated winding in this example embodiment has a common configuration with both the refrigerant can 204 configured for the concentrated winding 250 described with reference to FIGS. 2-12 and the refrigerant can 404 configured for the toroidal concentrated winding 410 described with reference to FIGS. 24-32. However, the shape of the toroidal concentrated winding in this example embodiment differs from the shape of the winding 250 in FIGS. 2-12 and the shape of the winding 410 described with reference to FIGS. 24-32. Therefore, the shape of the refrigerant can in this example embodiment differs from the shape of the refrigerant can 204 described with reference to FIGS. 2-12 and the shape of the refrigerant can 404 described with reference to FIGS. 24-32. Furthermore, the shape of the stator segments in this example embodiment differs from the shape of the stator segment 454 described with reference to FIGS. 24-32.

[0083] 33-36, a stator 500 includes a stator core 502 and a plurality of coolant cans 504. The stator core 502 has openings 506 through a longitudinal axis 508 of the stator 500. The coolant cans 504 are circumferentially disposed on the stator core 502 about the longitudinal axis 508 of the stator 500. In this embodiment, the coolant cans 504 are configured to enclose toroidal concentrated windings 510 (see FIG. 38) wound across the cross section of the stator core 502, the toroidal concentrated windings 510 being radially aligned with the longitudinal axis 508 of the stator 500, rather than at a radial angle 412 relative to the longitudinal axis 408 as with the toroidal windings 410 described with reference to FIGS. 24-32.

[0084] Referring now to Figures 37 and 38, the refrigerant can 504 and the toroidal concentrated winding 510 are shown in more detail. Figure 38 is an exploded view of the refrigerant can 504 having a first piece 520 and a second piece 522. Similar to the example refrigerant can 404 described with reference to Figures 24-32, when the first and second pieces 520, 522 of the refrigerant can 504 are joined, the refrigerant can 504 defines an interior compartment 524 of the refrigerant can 504. In some embodiments, as described throughout this disclosure, the first and second pieces 520, 522 of the refrigerant can 504 are joined, for example, by welding, adhesive, clips, or other known joining means. In some embodiments, a sealing member, such as a gasket, is disposed between the first and second pieces 520, 522 of the refrigerant can 504 to provide a seal between the first and second pieces 520, 522 of the refrigerant can 504.

[0085] The interior compartment 524 of the refrigerant can 504 is configured to enclose the toroidal winding 510 so as to fluidly isolate the toroidal winding 510 from the stator core 502 and other components of the electric motor. The assembled refrigerant can 504 has an opening 530 through the first piece 520 and the second piece 522 and an interior wall 532 extending through the interior compartment 524 of the refrigerant can 504. The opening 530 in the refrigerant can 504 is configured to receive a stator segment 536 of the stator core 502 (see FIGS. 39-41). A refrigerant inlet 540 is disposed in a rear wall 542 of the refrigerant can 504 and is in fluid communication with the interior compartment 524 of the refrigerant can 504. A refrigerant outlet 544 is disposed in a front wall 546 (see FIG. 40) of the refrigerant can 504 and is in fluid communication with the interior compartment 524 of the refrigerant can 504.

[0086] For purposes of illustration, the toroidal winding 510 is shown in Figure 38 as a solid piece with one or more conductors 550 emanating from the toroidal winding 510. The interior compartment 524 of the refrigerant can 504 is configured to receive the toroidal winding 510 such that the toroidal winding 510 is wrapped around the interior wall 532 of the refrigerant can 504. In this embodiment, the inlet 540 of the refrigerant can 504 is configured to not only pass fluid into the interior compartment 524 of the refrigerant can 504 but also to receive the conductors 550 of the toroidal winding 510 emanating from the refrigerant can 504.

[0087] In some embodiments, the conductors 550 of each winding 510 are electrically connected to one or more other components of the thermal management system of the electric machine and / or components of other parts of the electric machine. For example, in some embodiments, the conductors 550 of each winding 510 are electrically connected to the conductors 550 of other windings 510, which may be enclosed in separate refrigerant cans. In some embodiments, the conductors 550 of each winding 510 are electrically connected to active electrical circuitry. In some implementations, the conductors 550 of each winding 510 are electrically connected to active component electrical circuitry.

[0088] The interior compartment 524 of the can 504 defines a fluid flow path such that when liquid coolant is introduced into the interior compartment 524 of the can 504 through the inlet 540, the coolant passes through the toroidal windings 510 and exits the interior compartment 524 through the outlet 544 of the can 504. In this embodiment, the can 504 is fluidly isolated from the stator core 502, so that coolant flowing through the interior compartment 524 of the can 504 contacts the windings 510 but does not contact the stator core 502 or the stator segments 536.

[0089] 39-41, details of a refrigerant can 504 located on a portion of a stator core 502 are shown. Similar to the example embodiment described with reference to FIGS. 24-32, the stator core 502 is comprised of a plurality of stator segments 536, each corresponding to one of the plurality of refrigerant cans 504. While the stator segments 436 in the example embodiment described with reference to FIGS. 24-32 are "T-shaped," the stator segments 536 in this example embodiment are "L-shaped." The stator segment 536 has an upper portion 560 and a lower portion 562. The lower portion 562 has a first side 564, a second side 566, and an inner surface 568. The upper portion 560 has teeth 570 extending perpendicularly from the lower portion 562, an upper surface 572, and a lower surface 574. The teeth 570 are configured to receive the opening 530 of the refrigerant can 504 and bring the interior wall 532 of the refrigerant can 504 into contact with the top surface 572 , the bottom surface 574 , and the first side 564 .

[0090] Furthermore, each stator segment 554 mates with two other stator segments 554 arranged adjacent to it in the circumferential direction, so that the assembled stator segments 554 constitute the stator core 502. In this embodiment, the stator segments 554 have a first mating surface 580 and a second mating surface 582 that mate with the first mating surface 580. The stator 500 is assembled by mating the first mating surface 580 of one stator segment 554 with the second mating surface 582 of the other stator segment 554. Unlike the refrigerant cans 404 and stator segments 454 in FIGS. 24 to 32 , when two stator segments 554, each having a refrigerant can 504, are mated together, the refrigerant can 504 arranged on one segment 554 does not come into contact with the stator segments 554 of the other mating segment 554. The outer surfaces 572 of the stator segments 554 are configured to form a substantially continuous outer surface of the stator core 502 at the first diameter 590 (see FIG. 35 ) when the plurality of stator segments 554 are assembled together. The lower surfaces 568 of the stator segments 554 are similarly configured to form a substantially continuous inner surface of the stator core 502 at the second diameter 592 when the plurality of stator segments 554 are assembled together.

[0091] In some embodiments, the ratio of first diameter 590 to second diameter 592 of stator core 502 ranges from 10:9 to 3:2. In some embodiments, the ratio of first diameter 590 to second diameter 592 of stator core 502 ranges from 7:5 to 9:5. In some embodiments, the ratio of first diameter 590 to second diameter 592 of stator core 502 ranges from 13:10 to 2:1. In some embodiments, the ratio of first diameter 590 to second diameter 592 of stator core 502 ranges from 19:10 to 5:2.

[0092] In this disclosure, the thermal management system with the coolant can for the toroidal concentrated windings described above can be applied to either the stator or rotor, or both, of an electric machine. In some implementations, the stator of the electric machine can have toroidal concentrated windings and the rotor of the electric machine can have concentrated windings or distributed windings, or vice versa. In some implementations, the electric machine can have toroidal concentrated windings on components other than the stator or rotor.

[0093] As described throughout this disclosure, it may be advantageous to provide a thermal management system for an electric motor that includes a coolant can in the rotor of the electric motor. As described throughout this disclosure, currents induced in the rotor windings cause heat dissipation. Because eddy currents induced in the rotor core result in performance losses, it may be desirable to cool the rotor windings while maintaining a relatively high rotor core temperature to reduce eddy current generation. For example, during operation of the electric motor, the temperature of one or more portions of the rotor core may be higher than the temperature of one or more windings of the rotor. Thus, in some embodiments of the present disclosure, instead of or in addition to providing a coolant can in the stator of the electric motor, the rotor of the electric motor may include windings enclosed in one or more coolant cans.

[0094] 42-53 illustrate an example rotor having one or more refrigerant cans that enclose the rotor windings. The rotor 600 in this example is configured to rotate within an opening in a stator (not shown), such as opening 210 in stator 200 described with reference to FIGS. 2-12. The rotor 600 is symmetrical about its longitudinal axis 602 so that it is balanced when rotated about the longitudinal axis 602. Various rotor and rotor-can topologies (including refrigerant flow paths) are within the scope of this disclosure.

[0095] Referring now to FIG. 46, an exploded view of a rotor 600 is shown. In the illustrated example embodiment, rotor 600 includes a rotor core 604 (see FIG. 52), a shaft portion 606 having a first end 608 and a second end 610, and a plurality of coolant cans 612 circumferentially arranged around rotor core 614. Rotor core 614 is configured to receive an outer diameter 620 of shaft portion 606, the plurality of coolant cans 612, and a plurality of rotor poles 650. In some embodiments, rotor core 614 is made of a magnetically permeable material such as iron. In some embodiments, rotor core 614 includes rotor laminations, which reduce eddy currents in the magnetically permeable material of rotor core 614. In some embodiments, rotor core 614 includes other elements in addition to the magnetically permeable material. For example, in some embodiments, rotor core 614 includes an adhesive and / or an electrically insulating material (e.g., a varnish and / or a metal oxide). In some embodiments, portions of rotor core 614 include or are encapsulated in an epoxy or other insulating material.

[0096] A first end cap 622 is received by the first end 608 of the shaft 606, and a second end cap 624 is received by the second end 610 of the shaft 606. Plates 626 are disposed on either side of the refrigerant can 612 and are configured to support the refrigerant can 612 as the rotor 600 rotates. The refrigerant can 612 is configured to enclose one or more windings 630 of the rotor 600 (FIGS. 47 and 48). In this embodiment, the rotor 600 is provided with four refrigerant cans 612, which are arranged in a square pattern around the rotor core 614. In some embodiments, the rotor 600 includes no more than three refrigerant cans 612. In some embodiments, the rotor 600 includes more than four refrigerant cans.

[0097] 47 and 48, the refrigerant can 612 has a bottom piece 634 and a top piece 636. When the bottom piece 634 and the top piece 636 of the refrigerant can 612 are joined together, the pieces 634, 636 define an interior compartment 640 of the refrigerant can 612. The interior compartment 640 is configured to enclose the windings 630. The pieces 634, 636 can be joined together using one or more of a variety of techniques, including ultrasonic welding, adhesives, and mating clips. The techniques for joining the pieces 634, 636 of the refrigerant can 612 can also be used to join other portions of the refrigerant can 612 described herein. In some embodiments, a sealing member, such as a gasket, can be disposed between the pieces 634, 636 to provide a fluid seal between the pieces 634, 636 of the refrigerant can 612.

[0098] Refrigerant can 612 has an opening 642 extending through a top wall 644 and a bottom wall 646 of refrigerant can 612. Opening 642 defines an interior wall 648 of refrigerant can 612 and is configured to receive a lower portion 652 of a rotor pole 650.

[0099] Refrigerant can 612 has an inlet 656 and an outlet 658, each of which is in fluid communication with an interior compartment 640 of refrigerant can 612. Interior compartment 640 defines a liquid flow path 660 such that when refrigerant enters interior compartment 640 via inlet 656, the refrigerant flows through windings 630 and exits interior compartment 640 through outlet 658 of refrigerant can 612.

[0100] Figure 53 is a cross-sectional view of the assembled rotor 600 taken along line 53-53 in Figure 42. Each rotor pole 650 of the refrigerant can 612 is coupled to the rotor core 604 near the shaft 606. In some embodiments, the rotor poles 650 are made of a magnetically permeable material, such as iron. In some embodiments, the rotor poles 650 are made of the same material as the rotor core 614. In some embodiments, the rotor poles 650 comprise rotor laminations, which reduces eddy currents in the magnetically permeable material of the rotor poles 650 or the rotor core 614.

[0101] The first end cap 622 is received on the first end 608 of the stem 606 via an aperture 668 in the end cap 622. A first collar 670 is disposed between the aperture 668 in the first end cap 622 and the stem 606. The first end cap 622 has an interior compartment 672 with a plurality of inlet holes 674, which are circumferentially disposed around the aperture 668 and are in fluid communication with the interior compartment 672 of the first end cap 622. In this embodiment, a plurality of outlet holes 676 are disposed a radial distance from the aperture 668 and are in fluid communication with the interior compartment 672 of the first end cap 622. The outlet holes 676 in the first end cap 622 are configured to mate with the inlet 656 of the refrigerant can 612. In other embodiments, the number of outlet holes 676 in the first end cap 622 is greater than the number of refrigerant cans 612 in the rotor 600. In some embodiments, the number of outlet holes 676 in the first end cap 622 is less than the number of refrigerant cans 612 in the rotor 600.

[0102] A second end cap 624 is similarly received on the second end 610 of the stem 606 via an aperture 678 in the second end cap 624. A second collar 680 is disposed between the aperture 678 in the second end cap 624 and the stem 606. The second end cap 624 has an interior compartment 682 with a plurality of outlet holes 684 that are circumferentially disposed around the aperture 678 and are in fluid communication with the interior compartment 682 of the second end cap 624. In this embodiment, a plurality of inlet holes 686 are disposed a radial distance from the aperture 678 and are in fluid communication with the interior compartment 682 of the second end cap 624. The inlet holes 686 in the second end cap 624 are configured to mate with the outlet 658 of the refrigerant can 612. In other embodiments, the number of inlet holes 686 in the second end cap 624 is greater than the number of refrigerant cans 612 in the rotor 600. In some embodiments, the number of inlet holes 686 in the second end cap 624 is less than the number of refrigerant cans 612 in the rotor 600.

[0103] When the rotor 600 is assembled, the interior compartment 672 of the first end cap 622 is in fluid communication with the interior compartment 640 of each refrigerant can 612 via the inlet 656 of the refrigerant can 612, and the second end cap is in fluid communication with the interior compartment 640 of each refrigerant can 612 via the outlet 658 of the refrigerant can 612. In this manner, the interior compartments 672, 682 of the first and second end caps 622, 624 are in fluid communication with each other (see FIG. 52). In this embodiment, the inlet 656 of the refrigerant can 612 has a smaller radial height than the outlet 658 of that refrigerant can 612 (see FIGS. 44 and 45). Therefore, the outlet hole 676 of the first end cap 622 extends radially outwardly a distance less than the inlet hole 686 of the second end cap 624 (see FIGS. 44 and 45). This configuration can improve cooling efficiency in the refrigerant can because the warmer refrigerant, and therefore the lower fluid density, flows radially outward from the cooler refrigerant toward the outlet of the refrigerant can. In some embodiments, the radial height of the inlet 656 and the radial height of the outlet 658 of the refrigerant can 612 relative to the longitudinal axis 602 of the rotor 600 are equal.

[0104] Figure 51 is a cross-sectional view of the assembled rotor 600 taken along line 51-51 of Figure 42. As shown in Figure 51, the shaft portion 606 has a first counterbore 688 disposed at a first axial end 608 of the shaft portion 606 and extending axially along the longitudinal axis 602 of the shaft portion 606. A second counterbore 690 is disposed at a second axial end 610 of the shaft portion 606 and extends axially along the longitudinal axis 602 of the shaft portion 606. In this embodiment, the first counterbore 688 and the second counterbore 690 extend axially a distance that does not intersect with each other.

[0105] A plurality of outlet holes 692 are circumferentially disposed on the shaft portion 606 near the first end 608 and extend into the first counterbore 688. The plurality of inlet holes 692 are aligned with the inlet holes 674 in the first end cap 622 to place the first counterbore 688 in fluid communication with the internal compartment 672 of the first end cap 622 when the rotor 600 is assembled. A plurality of outlet holes 694 are circumferentially disposed on the shaft portion 606 near the second end 610 and extend into the second counterbore 690. The plurality of outlet holes 694 are aligned with the outlet holes 684 in the second end cap 624 to place the second counterbore 690 in fluid communication with the internal compartment 682 of the second end cap 624 when the rotor 600 is assembled. Thus, in this embodiment, when rotor 600 is assembled, first counterbore 688 is in fluid communication with second counterbore 690 through internal compartments 672, 682 of end caps 622, 624 and internal compartment 640 of refrigerant can 612.

[0106] 51 , in operation, as the rotor 600 rotates about the longitudinal axis 602, refrigerant flows into the first counterbore 688, which serves as the primary inlet for the rotor 600. The refrigerant flows radially outward within the first counterbore 688 through the outlet holes 692 in the shaft 606 and into the internal compartment 672 of the first end cap 622 via the inlet holes 674 in the first end cap 622. The refrigerant flows radially outward within the internal compartment 672 of the first end cap 622 (as a result of the rotation of the rotor 600 during operation) toward the outlet holes 676 in the first end cap 622. The refrigerant flows into the internal compartment 640 of each refrigerant can 612 via the outlet holes 676 in the first end cap 622 and the inlet holes 656 in the refrigerant can 612. Refrigerant flows through each internal compartment 640 of the refrigerant can 612 and through each winding 630 within the internal compartment 640 enclosed within the refrigerant can 612. The refrigerant exits the refrigerant can 612 through an outlet 658 in the refrigerant can and enters the internal compartment 682 of the second end cap 624 through an inlet hole 686 in the second end cap 624. The refrigerant then flows through an outlet hole 678 in the second end cap 624 and an inlet hole 694 in the shaft 606 into the second counterbore 690. In this example embodiment, the second counterbore 690 serves as the main outlet for the rotor 600, and the refrigerant flows out of the second counterbore 690.

[0107] In some embodiments, rotor 600 is configured such that a main outlet of rotor 600 is in fluid communication with the working volume of the motor. In some embodiments, refrigerant can 612 includes additional outlets in addition to outlet 658 that facilitate the flow of refrigerant from refrigerant can 612 other than through outlet 658. For example, refrigerant can 612 is configured to provide refrigerant spray cooling to a stator (not shown) or other components of the motor.

[0108] While Figures 42-53 illustrate an example rotor with a coolant can encapsulating the rotor windings, various other embodiments are within the scope of this disclosure. For example, the number of coolant cans and the number of windings encapsulated within the coolant cans may vary. The rotor windings may include toroidal concentrated windings or distributed windings. Alternative flow paths for the coolant may be used (e.g., coolant may enter and exit the rotor can via a path that does not pass through the shaft). Specific mechanisms and structures for fluid coupling and sealing between components may be implemented differently than those described with reference to Figures 42-53. In some embodiments, one or more of the features described herein for the stator coolant can may be applied to the rotor coolant can.

[0109] In some embodiments, it may be advantageous to provide a thermal management system that provides cooling to electrical components other than the windings. For example, FIG. 54 illustrates an example embodiment of a thermal management system for an electric motor rotor 600, as described with reference to FIGS. 42-53, that provides additional cooling to other electrical components of the rotor 600. The functional operation of the rotor in the example embodiment of FIG. 54 is substantially the same as that of the rotor 600 in the example embodiment described with reference to FIGS. 42-53. The rotor core, rotor poles, coolant can, and end caps in FIG. 54 also have the same structure and function as the rotor core 614, rotor poles 650, coolant can 612, and end caps 622, 624 in the embodiments described with reference to FIGS. 42-53. Accordingly, like reference numerals are used in FIG. 54 to refer to components with the same structure and function. However, the shaft in this example embodiment is different from the shaft 606 in the example embodiment described with reference to FIGS. 42-53.

[0110] In the exemplary embodiment shown in FIG. 54 , the shaft portion 706 has a through-hole 712 that extends along the longitudinal axis 602 of the rotor 600 and penetrates through a first axial end 708 and a second axial end 710 of the shaft portion 706. The shaft portion 706 of this embodiment differs from the shaft portion 606 of FIGS. 42-53 in that a through-hole 715 is used in the shaft portion 706 instead of the first and second counterbores 688, 690. At the first end 708 of the shaft portion 706, the through-hole 715 defines a mainstream inlet 720. At the second end 710 of the shaft portion 706, the through-hole 715 defines a mainstream outlet 722 of the rotor 600. The mainstream inlet 720 and the mainstream outlet 722 are in direct fluid communication with each other via the through-hole 712.

[0111] Continuing with reference to FIG. 54, when a volume of liquid refrigerant enters the mainstream inlet 720 at the first end 708 of the rotating shank 706, a first portion of the volume of liquid refrigerant flows along a first flow path 730, while a second portion of the volume of liquid refrigerant flows along a second flow path 732. The first flow path 730 branches off from a second flow path 732 at a plurality of exit holes 792 near the first end 708 of the shank 706. The first flow path 730 is identical to the flow path from the exit holes 792 in the shank 706 described above in the exemplary embodiment of FIGS. 42-53 (see FIG. 51). The second flow path 732 is defined as flow entering the mainstream inlet 720 at the first axial end 708 of the shank 706, along the through hole 712, and toward the mainstream outlet 722 at the second end 710 of the shank 706. At the multiple inlet holes 794 in the shaft portion 706, the first flow path 730 and the second flow path 732 merge toward the second end 710, and some or all of the constant volume of liquid refrigerant flows out of the through hole 712 through the main outlet 722 of the shaft portion 706.

[0112] In this embodiment, an electrical component 750 is disposed within the through-hole 712 of the shaft 706 between the plurality of inlet holes 794 and outlet holes 792 of the shaft 706, i.e., on the second flow path 732. Thus, a second portion of the constant volume of coolant flows toward and near the electrical component 750, providing cooling to the electrical component 750, while a first portion of the constant volume of coolant provides cooling to the windings 630 within the coolant can 612 of the rotor 600. This embodiment may be advantageous because the second portion of the constant volume of coolant is not exposed to the high temperature of the windings 630, and the windings 630 are cooled by the first portion of the constant volume of coolant.

[0113] In some embodiments, the volumes of the first and second portions of the volume of refrigerant are equal. In some embodiments, the first portion of the volume of refrigerant is greater than the second portion of the volume of refrigerant, or vice versa. In some embodiments, the through-hole 712 of the shaft 706 has a cross-section with multiple different diameters. For example, the diameter of the through-hole 712 of the shaft 706 near the main inlet 720 and near the main outlet 722 is greater than the diameter of the central portion of the through-hole 712 of the shaft 706 located between the two portions, or vice versa.

[0114] In some embodiments, rotor 600 can have three or more parallel coolant flow paths through rotor 600. Additionally, electrical components can be located within any of the coolant flow paths within rotor 600. For example, with reference to FIG. 51 , electrical components can be located within first counterbore 688 of the shaft, or within second counterbore 690 of shaft 606, or both. In other embodiments, two or more coolant flow paths can be provided in parallel or in series across the rotor, stator, motor, and / or motor assembly, and the flow and / or temperature of each coolant flow path can be regulated.

[0115] Although this disclosure presents example embodiments in which the rotor is surrounded by the stator, in some embodiments the outer rotor and inner stator comprise a refrigerant can as described throughout this disclosure.

[0116] The stator and rotor embodiments described throughout this disclosure are exemplary, and other embodiments within the scope of this disclosure may vary in aspects of the thermal management system of an electric motor using refrigerant cans. For example, the number of windings enclosed in each refrigerant can, the number of inlets and / or outlets in each refrigerant can, the number of teeth on each stator or rotor, and the number of teeth enclosed by each refrigerant can may differ from the examples shown throughout this disclosure. The shapes of the refrigerant cans, windings, stator cores, and rotor cores may differ from the shapes described throughout this disclosure.

[0117] In various embodiments, the refrigerant can is made of, for example, plastic or other material that is resistant to corrosion by the refrigerant and capable of withstanding the elevated temperatures inside the motor. In some embodiments, the refrigerant can is made of thermally and / or electrically insulating material. In some embodiments, the refrigerant can is fabricated by, for example, overmolding or insert molding. In some embodiments, the refrigerant can is made of metal and / or composite materials. The thickness of one or more walls of the refrigerant can body can be 0.15 mm or less in various embodiments. In other embodiments, the thickness of the walls of the refrigerant can body can be in the range of approximately 0.15 mm to 0.25 mm. In other embodiments, the thickness of the walls of the refrigerant can body can be in the range of approximately 0.25 mm to 0.5 mm. In other embodiments, the thickness of the walls of the refrigerant can body can be in the range of approximately 0.5 mm to 1.0 mm.

[0118] The above-described coolant can and its components and / or the stator and / or rotor components can be fabricated by additive manufacturing techniques, such as additive manufacturing. To do so, numerous additive manufacturing techniques can be implemented to form the coolant can, such as bath photopolymerization, material jetting, binder jetting, powder bed fusion, material extrusion, directed energy deposition, and / or sheet lamination. In some embodiments, the coolant can or its components can be additively fabricated directly onto the stator and / or rotor. In some embodiments, a portion of the coolant can can be additively fabricated onto the surface of the windings located at the bottom of the coolant can.

[0119] In some embodiments, various electrical components may be electrically coupled or connected to one or more windings disposed on a stator, rotor, motor, and / or motor assembly. FIG. 55 illustrates a discrete circuit component 800 electrically coupled or connected to a winding 810. In some embodiments, the discrete circuit component 800 comprises one or more subcomponents. For example, the discrete circuit component 800 may include an encapsulated integrated circuit or an encapsulated active or passive circuit component. In some embodiments, two or more separate windings 810 are coupled to each other by a discrete circuit component 800 associated with each of the windings 810.

[0120] In some embodiments, discrete circuit components 800 include passive circuit components electrically coupled or connected to one or more windings disposed on the stator and / or rotor. In some embodiments, the passive circuit components include, by way of specific, non-limiting example, diodes or capacitors. In some embodiments, the active circuit components include one or more transistors. In some embodiments, discrete circuit components 800 include integrated circuits electrically coupled or connected to one or more windings disposed on the stator and / or rotor. In some embodiments, the integrated circuits include active or passive frequency filters.

[0121] In some embodiments, the discrete circuit component 800 includes a rectifier shorted to at least one winding of the rotor. The rectifier can serve to reduce current ripple in the rotor winding by introducing asymmetry into the rotor winding's response to the magnetic field generated by the stator winding, or to control the electric machine's current or voltage in the rotor, stator, or both. In some embodiments, the rectifier can be provided as an auxiliary circuit within the electric machine. In some embodiments, the rectifier can comprise a diode, such as a pn junction diode, a gas diode, a Zener diode, or a Schottky diode. In some embodiments, if the rectifier includes a Schottky diode, the Schottky diode can be a silicon carbide diode. In some embodiments, the rectifier can comprise an active circuit, such as an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOSFET). In some embodiments, the rectifier comprises an AC / DC rectifier that receives alternating current (AC) power from an AC power source, such as a utility grid or an external generator, and outputs direct current (DC) power to other components of the electric machine and / or to other machines or systems external to the electric machine. For example, the electric machine can be a generator that generates AC power through one or more windings, the generator comprising one or more discrete circuit components including the AC / DC rectifier, which outputs DC power to an external electric machine, such as the rotor of an electric motor.

[0122] In some embodiments, the discrete circuit component 800 includes an electrical switch electrically coupled or connected to one or more windings of the stator and / or rotor. The electrical switch may be configured to control current to and / or from one or more windings 810. In some embodiments, the electrical switch includes a bus bar electrically connected to a power source. In some embodiments, the electrical switch and bus bar are encapsulated in one or more refrigerant cans with one or more windings coupled to the refrigerant cans.

[0123] In some embodiments, discrete circuit component 800 includes one or more switches or semiconductor devices coupled to one or more windings and disposed in a conductive network, which may include multiple microinverters in a microinverter network. In such embodiments, the multiple switches or semiconductor devices disposed in a conductive network are provided as part of an electric machine, such as an electric motor, and are electrically connected to an electronic motor controller of the electric motor that can regulate the supply of current or voltage to the electric motor.

[0124] Current can flow through the discrete circuit components 800 and through the windings 810 themselves, which can cause the discrete circuit components 800 to heat up during motor operation. Thus, in some embodiments, the discrete circuit components 800 can be encapsulated in one or more coolant cans to which one or more windings 810 are coupled, such that the coolant is in contact with the windings and one or more discrete circuit components 800. In this embodiment, the discrete circuit components 800 can be cooled simultaneously with the windings 810. In some embodiments, some discrete circuit components 800 and subcomponents are encapsulated in one or more coolant cans to which one or more windings are coupled, while some discrete circuit components 800 and subcomponents are not encapsulated in the coolant cans to which one or more windings are coupled.

[0125] Various embodiments of the coolant can inlet(s) are within the scope of this disclosure. In addition to the fluid inlets described throughout this disclosure, one or more coolant can inlet(s) in some embodiments also function as ports for wires or other conductors, such as wires for energizing windings or wires for transmitting sensor signals. For example, referring to FIG. 13, three of the four inlet openings 390 in end cap piece 304 can support wires for each stator phase of a three-phase motor, with the fourth inlet opening 390 in end cap piece 304 serving as a coolant inlet. In some embodiments, one or more coolant can inlet(s) can be configured to function as both a wire port and a fluid inlet (FIGS. 33-41).

[0126] In some embodiments, the coolant can can have internal protrusions (e.g., interior walls, bumps, and / or ridges, etc.). FIG. 56 illustrates several example protrusions 854 that can be provided on the interior surface 852 of an example coolant can 850. In some embodiments, the protrusions 854 are configured to apply pressure to one or more windings enclosed within the coolant can 850, thereby holding the windings in place and improving the mechanical stability of the motor. In some embodiments, the protrusions 854 have a labyrinth shape 856 that is configured to increase the distance (and therefore the time) that the coolant flows through the coolant can 850 and contacts the one or more windings.

[0127] Continuing with reference to FIG. 56, protrusions 854 can have a variety of shapes and sizes. In some embodiments, protrusions 854 include bumps (e.g., an array of bumps) that increase turbulence in the coolant flow, thereby improving cooling effectiveness. In some embodiments, the bumps on protrusions 854 are shaped to not significantly impede coolant flow. In some embodiments, protrusions 854, including the bumps, are square rather than round to increase turbulence in the coolant flowing through the coolant can. In some embodiments, protrusions 854 include multiple fins oriented parallel to the coolant flow in the coolant can, thereby increasing the surface area of ​​the inner surface 852 of coolant can 850 in contact with the flowing coolant while minimizing drag caused by the coolant flow. In some embodiments, protrusions 854 extend from inner surface 852 of coolant can 850 by about 0.25 mm to about 5 mm. In some embodiments, instead of or in addition to a configuration in which the protrusions 854 include bumps, the inner surface 852 of the refrigerant can 850 can have recesses or dimples, such as dimples that extend into the inner surface 852 around the periphery of the trapped windings, which can induce turbulence in the flow of refrigerant within the internal compartment of the refrigerant can 850.

[0128] In some embodiments, the refrigerant can has a smooth surface on the side of the air gap between the stator and rotor of the electric motor, which may be the inside or outside surface of the refrigerant can, depending on whether the particular refrigerant can is disposed on the stator or rotor. For example, as shown in Figures 2-12, the bottom wall 246 on the air gap side of the refrigerant can 204 can be formed to be flush with the corresponding surface of the stator tooth 214 (see Figure 12). When the refrigerant can 204 and the stator tooth 214 are assembled, the inner surface of the stator 200 formed by the combination of the bottom wall 246 of the refrigerant can 204 and the bottom surface of the stator tooth can be smooth, thereby reducing windage losses in the air gap in some embodiments.

[0129] In some electric machines, it may be desirable to provide systems and methods for an electric machine thermal management system that selectively provides cooling to some components of the electric machine while isolating such cooling from other components of the electric machine. For example, in conventional electric motor designs, the temperature of the stator core and / or rotor core (which may have windings disposed thereon) is kept lower than the temperature of the windings to create an effective thermal gradient across the motor windings. However, as noted above, as the temperature of the motor core decreases, the output performance of the electric motor may decrease, which is the opposite of the relationship between winding temperature and motor performance. The reason for this inverse relationship in conventional electric motor designs is that the stator core and / or rotor core act as a heat sink by extracting heat from the windings disposed thereon. Thus, traditional motor designs typically improve motor performance by maintaining a lower winding temperature during motor operation. This is often achieved as a result of heat transfer from the windings directly to the stator core and / or rotor core and / or from the windings through the stator core and / or rotor core to a liquid jacket. Thus, traditional thermal management approaches aim to cool both the core and the windings, as described above. However, improved or maintained motor performance can be achieved as long as heat is maintained in the stator core and / or rotor core, since core performance increases with increasing temperature, and the gradient does not need to be less than that of the windings. One undesirable phenomenon of traditional electric motor design is that overall motor performance can be improved if the stator core and / or rotor core are maintained at a temperature that is independent of cooling the windings disposed therein.

[0130] An electric machine, such as an electric motor, equipped with a thermal management system having a refrigerant can disclosed herein can operate the stator core and / or rotor core at higher temperatures because the stator core and / or rotor core do not need to facilitate cooling of the windings disposed therein. In some embodiments, the refrigerant can can be configured to facilitate differentiated thermal management of one or more windings of a stator compared to a stator core of a stator and / or to facilitate differentiated thermal management of one or more windings of a rotor compared to a rotor core of a rotor. For example, at the initial start of operation of an electric motor, where both the windings and the stator core and / or rotor core may be relatively cool at the same temperature, it may be desirable to increase the temperature of the stator core and / or rotor core while cooling the windings disposed therein to improve motor performance or efficiency.

[0131] Continuing with the above non-limiting example, the coolant can can be configured with coolant flow paths that remove heat from the windings and transfer heat to the stator core and / or rotor core. In such embodiments, under steady-state, continuous operating conditions, the winding temperature averages equal to the average core temperature for the same operating conditions, where the stator core and / or rotor core temperature is measured directly with a thermoprobe, the winding temperature is measured by electrical resistance, or alternatively, is obtained as a thermal gradient across the coolant can. In some embodiments, the winding temperature averages 5°C lower than the average temperature of the stator core and / or rotor core in which the winding is disposed. In some embodiments, the winding temperature averages 7.5°C lower than the average temperature of the stator core and / or rotor core in which the winding is disposed. In some embodiments, the winding temperature averages 10°C lower than the average temperature of the stator core and / or rotor core in which the winding is disposed. In some embodiments, the winding temperature averages 15°C lower than the average temperature of the stator core and / or rotor core in which the winding is disposed. In some embodiments, the temperature of the windings is, on average, at least 20° C. lower than the average temperature of the stator core and / or rotor core in which the windings are disposed.

[0132] In some electrical designs and operations, it may be advantageous to electrically isolate one or more windings from other components of the electric machine or from the system as a whole. For example, in some embodiments, the coolant can may be configured to facilitate electrical isolation of one or more windings from the stator core and / or rotor core. In some embodiments, the coolant can may be part of an insulation structure of the electric machine, which insulation structure is configured to electrically isolate one or more windings of the electric machine from other components of the electric machine or from electrical components external to the electric machine.

[0133] In some embodiments, the systems described in this disclosure for thermal management of electric machines, such as electric motors with coolant cans, can include a temperature control module that monitors and / or regulates the coolant flow and temperature of the electric machine.

[0134] 57 is a schematic diagram of an example embodiment of a temperature control module 900 for an electric motor 902 including a stator 904 and a rotor 906. In some embodiments, the temperature control module 900 is electrically coupled to a motor controller 908, which coordinates the primary electrical and kinematic operation of the motor 902. In some embodiments, part or all of the temperature control module 900 is incorporated into the motor controller 908.

[0135] The temperature control module 900 may be coupled to the stator 904 and / or rotor 906 via couplings 910, 912, respectively. The couplings 910, 912 may be respective fluid and / or electrical couplings between the temperature control module 900 and the stator 904 and / or rotor 906, respectively. The stator 904 and rotor 906 may be any stator and rotor described in this disclosure or any other stator and rotor not described in this disclosure.

[0136] The temperature control module 900 may include various sub-modules 920, each of which may be communicatively coupled to any or all of the other sub-modules 920.

[0137] In some embodiments, temperature control module 900 includes one or more temperature sensors 922 that measure the temperature at stator 904 or rotor 906. For example, in some embodiments, temperature sensor 922 measures the temperature at one or more coolant cans disposed on stator 904 and / or rotor 906, thereby providing temperature data for the windings enclosed in the coolant cans. In some embodiments, temperature sensor 922 measures the temperature of the stator core (e.g., stator tines or stator laminations, etc.) and / or rotor core (e.g., rotor tines or rotor laminations, etc.). In some embodiments, temperature sensor 922 is in direct fluid communication with the coolant (e.g., temperature sensor 922 is located within the coolant can or in the inlet / outlet path to the coolant can). In some embodiments, temperature sensor 922 includes one or more of a thermocouple, a resistance temperature sensor, a thermistor, and an optical temperature sensor.

[0138] In some implementations, the electrical resistance of one or more windings attached to a rotor or stator can be measured to estimate future heating loads on the rotor or stator. This resistance can be measured, for example, by motor controller 908, which can then send a signal to controller 930 of temperature control module 900, causing controller 930 to increase or decrease coolant flow in response to the measured temperature. Because winding resistance can be a leading indicator of cooling demand (e.g., if the power dissipated in the winding increases, this increase will manifest as a rise in winding resistance before there is a measurable change in coolant temperature), this approach can provide more effective and / or efficient cooling than approaches that wait until measured temperature indicates the need to change the coolant flow.

[0139] In some embodiments, the temperature control module 900 includes one or more flow sensors 924, for example, within the refrigerant can and / or along the flow path to and from the refrigerant can (e.g., on the rotor shaft through which the refrigerant flows). In some embodiments, the flow sensors 924 measure the refrigerant flow rate. In some embodiments, the flow sensors 924 measure the volume of the refrigerant (e.g., to determine whether the refrigerant can is full of refrigerant).

[0140] In some embodiments, the temperature control module 900 includes one or more pressure sensors 926, for example, located within one or more refrigerant cans or along the flow path from and / or to one or more refrigerant cans. The pressure sensors 926 can be configured to measure the fluid pressure of the refrigerant flow for analysis by the temperature control module 900.

[0141] In some embodiments, the temperature control module 900 and the stator 904 and / or rotor 906 are configured to maintain a positive pressure of refrigerant within one or more refrigerant cans relative to pressure outside the one or more refrigerant cans (e.g., relative to pressure existing in an air gap between the stator 904 and the rotor 906). Positive pressure within the one or more refrigerant cans can reduce backflow of refrigerant and provide a consistent flow of refrigerant within the one or more refrigerant cans compared to isobaric or negative pressure within the one or more refrigerant cans. Furthermore, positive refrigerant pressure within the one or more refrigerant cans can reduce discontinuous refrigerant flow within the refrigerant cans during motor operation, maintaining a full or substantially full refrigerant level within the one or more refrigerant cans, thereby improving mechanical stability of the motor.

[0142] In some embodiments, the refrigerant regulation configuration of the temperature control module 900 can include one or more pumps 950 and / or one or more flow regulators 952. The refrigerant pump 950 is fluidly coupled (e.g., by tubing and / or piping) to one or more inlets of one or more refrigerant canisters. In some embodiments, the refrigerant pump 950 is fluidly coupled to one or more outlets of one or more refrigerant canisters to establish a refrigerant flow loop. In some embodiments, the flow regulator 952 can include, for example, a valve that can vary and / or start or stop the refrigerant flow therethrough. In some embodiments, the refrigerant pump 950 is adjustable, for example, to increase or decrease the refrigerant outlet pressure and / or increase or decrease the refrigerant flow rate. In some embodiments, separate pumps are used for the stator 904 and the rotor 906. In some embodiments, the refrigerant pump 950 and / or the flow regulator 952 can be configured by the controller 930 of the temperature control module 900. Controller 930 may include one or more processors 932, one or more storage devices 934, and one or more memory devices 936. In some implementations, storage devices 934 and / or memory devices 936 store machine-readable, non-transitory instructions that enable active control by controller 930.

[0143] Flow regulator 952 may be implemented in software to control the flow rate of one or more coolant pumps 950. In certain embodiments, control of flow regulator 952 may be controlled in response to operating conditions, such as an operating duty cycle or an expected duty cycle. Such control may be achieved through look-up tables, multiple-input multiple-output (MIMO) controllers, plant models such as model predictive control (MPC), and the like.

[0144] In some embodiments, the controller 930 receives a stream of temperature data from one or more temperature sensors 922 and, in response, sends signals to the coolant pump 950 and / or flow regulator 952 to adjust the coolant flow. A "stream" of data in this context refers to at least an analog and / or digital electrical entity that can be interpreted by the controller to indicate corresponding measurements and / or settings.

[0145] For example, if a particular temperature sensor 922 indicates that the temperature of one or more windings of the stator 904 exceeds a threshold value, the controller 930 may send a control signal to one or more refrigerant cans disposed in the stator 904 and / or a valve in fluid communication with the stator 904 to increase refrigerant flow to the stator 904 (e.g., the control signal may switch the valve to a more open position).

[0146] In some embodiments, the controller 930 receives a stream of refrigerant flow data from one or more flow sensors 924 and, in response, sends a signal to the refrigerant pump 950 and / or flow regulator 952 to adjust the refrigerant flow. For example, if a particular flow sensor 924 indicates that the refrigerant flow in one or more refrigerant cans disposed in the rotor 906 exceeds a threshold, the controller 930 may send a control signal to a valve to reduce the refrigerant flow to the one or more refrigerant cans in the rotor 906.

[0147] In some implementations, the controller 930 receives a stream of refrigerant pressure data from one or more pressure sensors 926 and, in response, sends signals to the refrigerant pump 950 and / or flow regulator 952 to adjust the refrigerant pressure. For example, if a particular pressure sensor 926 indicates that the refrigerant flow paths in one or more refrigerant cans of the stator 904 are no longer at a positive pressure relative to the pressure in other volumes of the motor 902, the controller 930 can send a control signal to a valve to increase refrigerant flow to one or more refrigerant cans of the stator 904.

[0148] In some embodiments, controller 930 also sends and receives control signals in response to other data. For example, in some embodiments, controller 930 receives a signal from motor controller 908 indicating a change in motor conditions (e.g., an imminent speed increase of motor 902) and, in response, sends a corresponding control signal that matches the coolant flow conditions to the predicted operating conditions of motor 902. This proactive approach may provide more effective and / or efficient cooling than, for example, an approach that waits until measured temperature indicates that coolant flow needs to be increased.

[0149] In some embodiments, motor controller 908 sends a stream to controller 930 indicative of the electrical resistance of one or more windings of stator 904 and / or rotor 906, or sends a signal to controller 930 indicating that the electrical resistance of one or more windings of stator 904 and / or rotor 906 exceeds, for example, a threshold value. In response, controller 930 sends a signal to coolant pump 950 and / or flow regulator 952 to adjust the coolant flow.

[0150] The refrigerant flow control method is not limited to the above examples utilizing thresholds. In various embodiments, the refrigerant flow control method can include a continuous refrigerant flow response based on continuous input data (e.g., electrical resistance or temperature data, etc.). In some embodiments, the refrigerant flow control can include using machine learning to predict an expected required refrigerant flow rate based on motor operating parameters, where the machine learning algorithm is executed by one or more processors 932 of the controller 930 or the motor controller 908 of the temperature control module 900.

[0151] In some embodiments, the temperature control module 900 includes a communications module 928 configured to receive and / or transmit signals from, for example, the sensors, motor controller 908, or any of the other devices or sources described above. In some embodiments, the communications module 928 includes a wireless communications device, such as, for example, a short-range communications module, a Bluetooth® module, a cellular communications module, and / or a Wi-Fi® communications module. In some embodiments, the communications module 928 includes hardwired connections to the components to which the communications module 928 is communicatively coupled.

[0152] In some embodiments, the controller 930 of the temperature control module 900 is at least partially mechanical. For example, in some embodiments, the controller 930 adjusts the refrigerant flow at least in part through mechanical response to temperature, pressure, and / or flow rate readings instead of or in addition to computer processing of machine-readable instructions.

[0153] In some embodiments, the electric machines described in this disclosure, such as electric motors with coolant cans, can include one or more coolant manifolds that regulate the flow of coolant through the electric machine.

[0154] 58 is a schematic diagram of an example embodiment of an enclosed coolant manifold 970 that receives a flow of coolant from a coolant pump 972. The coolant manifold 970 is fluidly connected (e.g., by pipes, tubing, etc.) to one or more inlets of one or more coolant cans 974. One or more outlets of the one or more coolant cans 974 deliver the coolant to a sump 976. The coolant pump 972 is configured to draw coolant from the sump 976 to complete the coolant flow loop.

[0155] In some embodiments, the coolant pump 972 can be one or more of the coolant pumps 950 described above that are configurable by the controller 930 of the temperature control module 900 (see FIG. 57). In some embodiments, the coolant manifold 970 can be one or more of the flow regulators 952 described above that are configurable by the controller 930 of the temperature control module 900 (see FIG. 57).

[0156] In some embodiments, the outlets of the refrigerant cans located on the stator and / or rotor cans can be configured to directly provide cooling to other components of the electric motor. For example, in some embodiments, the refrigerant cans are configured so that the refrigerant flows through the stator and / or rotor cans before entering the working volume of the electric motor (e.g., via an outlet that discharges directly into the working volume of the electric motor). In some embodiments, the outlets of the refrigerant cans are positioned so that the refrigerant exiting the stator and / or rotor cans enters a portion of the working volume where the windage losses caused by the refrigerant are relatively low, such as a sump port located at the bottom of the motor in the direction of gravity and in fluid communication with the working volume (see FIG. 58). The fluid level in the sump is adjusted so that the refrigerant in the sump does not reach the lowest point in the direction of gravity of the air gap. In such embodiments, the sump can be in fluid communication with one or more fluid pumps (see FIG. 58).

[0157] Additionally, in some embodiments, the outlet of the refrigerant can is configured to direct refrigerant from the refrigerant can to specific components of the motor, such as other components that may heat up during motor operation and for which cooling may be desirable. For example, in some embodiments, the refrigerant can outlet directs refrigerant to contact bearings of the motor to cool the bearings.

[0158] In some embodiments, the outlets of a refrigerant can disposed on the rotor can be configured to provide spray cooling to the stator windings. In some embodiments, the outlets of a refrigerant can disposed on the stator can be configured to provide spray cooling to the rotor windings. For example, referring to FIGS. 42-53 , a peripheral outlet is provided on the top wall 644 of the refrigerant can 612 near the inlet and outlets 656, 658. When the refrigerant can 612 rotates, a volume of refrigerant can 612 can exit the refrigerant can 612 from the peripheral outlet and contact the stator (not shown) surrounding the rotor 600. This embodiment can provide spray cooling to the stator windings, without the need for the stator refrigerant can to be enclosed. Conversely, in some embodiments, and with particular reference to Figures 2-12, an additional axially oriented outlet is provided in the bottom wall 246 of the coolant can 204 of the stator 200, and this additional axially oriented outlet allows a certain volume of coolant to flow out of the coolant can 204 and into the air gap of the motor, thereby providing spray cooling to the rotor.

[0159] While various embodiments described throughout this disclosure relate to the flow of coolant within the electric machine, other embodiments within the scope of this disclosure may vary in various aspects of the coolant. In some embodiments, the liquid coolant includes a mixture of a refrigerant and a lubricant that provides sufficient cooling to one or more windings enclosed in one or more coolant cans, while also providing cooling and lubrication to other components of the electric machine external to the cans. In some embodiments, the coolant is a gas that provides gas cooling to one or more windings enclosed in one or more coolant cans. In some embodiments, the one or more refrigerant cans include two or more internal compartments, the two or more internal compartments being fluidly isolated from one another and each having an inlet and an outlet, where one internal compartment encloses one or more windings and has an inlet configured to receive refrigerant, and the inlet of one or more other internal compartments is configured to receive a flow of lubricant through the one internal compartment and toward one or more outlets, which may be directed toward other components of the electric machine. In some embodiments, the thermal management system of the electric machine may include two or more separate fluid pumps, at least one configured to pump refrigerant and one configured to pump lubricant. In such embodiments, the thermal management system may include a fluid manifold in fluid communication with the two or more fluid pumps, such that the refrigerant and lubricant pumped into the manifold mix within the manifold as they flow to the one or more refrigerant cans.

[0160] While some of the above discussion has been centered around systems such as various electric machines that include wire-wound refrigerant cans, those skilled in the art will recognize inherent disclosure of corresponding methods of use (or operation) of the disclosed systems and methods of installation of the disclosed systems. Thus, some non-limiting examples of the present disclosure may include methods of use, manufacture, and installation of electric machines that include wire-wound refrigerant cans.

[0161] While some of the above discussion has been centered around thermal management systems, such as various electric machines with thermal management systems having a refrigerant can, those skilled in the art will recognize inherent disclosure of corresponding methods of use (or operation) of the disclosed systems and methods of installation of the disclosed systems. Thus, some non-limiting examples of the present disclosure may include methods of use, manufacture, and installation of electric machines with thermal management systems having a refrigerant can.

[0162] For example, some embodiments may include a method for thermally managing an electric machine having a thermal management system by flowing a coolant through one or more coolant cans fluidly isolated from other components of the electric machine and enclosing one or more windings or conductive elements of the electric machine in internal compartments thereof, such that the one or more windings of the electric machine are cooler than other components of the electric machine. In one example embodiment, referring to Figures 57 and 58, temperature control module 900 causes coolant pump 950 (or coolant pump 972 in Figure 58) and / or flow regulator 952 to pump coolant through one or more coolant cans 974, such that the one or more windings enclosed in the one or more coolant cans 974 are cooler than other components of stator 904 and / or rotor 906. In some embodiments, coolant pump 972 pumps coolant to coolant manifold 970 and one or more coolant cans 974 in fluid communication with coolant manifold 970 .

[0163] In some embodiments, the method may further include detecting the temperature of one or more windings enclosed in one or more refrigerant cans and determining whether the detected temperature exceeds a threshold. Thereafter, if the detected temperature is determined to exceed the predetermined threshold, additional refrigerant is caused to flow into the internal compartments of the one or more refrigerant cans. In one exemplary embodiment, referring to FIGS. 57 and 58 , a controller 930 of the temperature control module 900 receives, stores, and processes input from one or more temperature sensors 922 to cause a pump 950 (or refrigerant pump 972 in FIG. 58 ) and / or a flow regulator 952 to pump additional refrigerant into one or more refrigerant cans 974 whose temperature is determined to exceed the predetermined threshold. It should be apparent that the method described above is also applicable to detected electrical resistance of one or more windings and a predetermined threshold value of electrical resistance.

[0164] In some embodiments, the method further includes detecting pressure in one or more refrigerant cans and in a working volume of the electric machine. It is determined whether the detected pressure in the one or more refrigerant cans is lower than the detected pressure in the working volume of the electric machine. A positive pressure is then applied by the pump to the one or more refrigerant cans relative to the detected pressure in the working volume of the electric machine. In one example embodiment, referring to FIGS. 57 and 58 , a controller 930 of the temperature control module 900 receives, stores, and processes inputs from one or more pressure sensors 926 to cause the pump 950 (or refrigerant pump 972 in FIG. 58 ) and / or flow regulator 952 to pump additional refrigerant into one or more refrigerant cans 974, i.e., to increase a flow pressure determined to be lower than the detected pressure in the working volume, such as the air gap between the stator 904 and rotor 906 of the electric motor 902.

[0165] While the present invention has been described and illustrated in the foregoing non-limiting examples, it should be understood that the disclosure is merely illustrative and that numerous changes in the details of the implementation of the present invention may be made without departing from the spirit and scope of the present invention, which is limited only by the appended claims. The elements of the non-limiting examples disclosed herein may be combined and rearranged in various ways.

[0166] Furthermore, the non-limiting examples of the disclosure provided herein are not limited in application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The present invention is capable of other non-limiting examples and of being practiced or embodied in various forms. It should also be understood that the phrases and terminology used herein are for purposes of description and should not be construed as limiting the present invention. As used herein, the terms "including," "comprising," or "having" and variations thereof are meant to include the item that follows, equivalents thereof, and other items. Unless otherwise specified or limited, the terms "mounted," "connected," "supported," and "coupled," as well as variations thereof, are used broadly and encompass both direct and indirect mounting, connecting, supporting, and coupling. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings.

[0167] Additionally, the language and terminology used herein are for purposes of explanation and should not be considered limiting of the present invention. In this application, terms such as "right," "left," "front," "rear," "upper," "lower," "upper," "lower," "top," or "bottom," and variations thereof, are for purposes of explanation and should not be considered limiting of the present invention. Unless otherwise specified or limited, the terms "attached," "connected," "supported," and "coupled," and variations thereof, are used broadly and encompass both direct and indirect attachments, connections, supports, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings.

[0168] Unless otherwise specified or limited, phrases such as "at least one of A, B, and C," "one or more of A, B, and C," etc., mean A or B or C, or any combination of A, B, and / or C, including combinations with the plural or singular of A, B, and / or C.

[0169] In some non-limiting examples, aspects of the present disclosure, including computer implementations of methods, can be implemented as a system, method, apparatus, or article of manufacture using standard programming or engineering techniques to produce software, firmware, hardware, or any combination thereof that controls a processor apparatus, a computer (e.g., a processor apparatus operably coupled to a memory), or an electronically operated controller to perform aspects detailed herein. Thus, for example, non-limiting examples of the present invention can be implemented as a set of instructions tangibly embodied on a non-transitory computer-readable medium such that a processor apparatus executes the instructions upon reading the instructions from the computer-readable medium. Some non-limiting examples of the present invention can include (or use) devices such as automation equipment, special-purpose computers, or general-purpose computers, including various computer hardware, software, firmware, etc., consistent with the discussion below.

[0170] As used herein, the term "article of manufacture" includes a computer program accessible from any computer-readable device, carrier (e.g., a non-transitory signal), or medium (e.g., a non-transitory medium). For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), smart cards, and flash memory devices (e.g., cards, sticks, etc.). It will also be apparent that carrier waves may be used to carry computer-readable electronic data, such as computer-readable electronic data used in sending and receiving email or accessing a network, such as the Internet or a local area network (LAN). Those skilled in the art will recognize that many modifications can be made to the above arrangements without departing from the scope or spirit of the invention as defined by the appended claims.

[0171] Figures and other descriptions may generally depict certain operations of a method of the present invention or of a system for performing the method. Unless otherwise specified or limited, the depiction in a figure of certain operations depicted in a particular spatial order may not necessarily require those operations to be performed in a particular order corresponding to that particular spatial order. Thus, certain operations depicted in figures and elsewhere may be performed in an order different from that explicitly depicted or described, as appropriate for particular, non-limiting examples of the present invention. Additionally, in some non-limiting examples, certain operations may be performed in parallel, including by dedicated parallel processing devices or separate computers interoperating as part of a larger system.

[0172] When used in this application in the context of computer implementation, unless otherwise specified or limited, the terms "component," "system," "module," and the like include hardware, software, a combination of hardware and software, or part or all of a computer-related system, including running software. For example, a component can be a processor unit, a process being executed (or executable) by a processor unit, an object, an executable file, a thread of execution, a computer program, or a computer. For example, both an application running on a computer and that computer can be a component. One or more components (or systems, modules, etc.) can reside within a process or thread of execution, can be local to one computer, can be distributed across two or more computers or other processor units, or can be included in other components (or systems, modules, etc.).

[0173] As used herein, the terms "controller," "processor," and "computer" include any device capable of executing a computer program or any device with logic gates that perform the functions described above. For example, they may include a processor, a microcontroller, a field programmable gate array, a programmable logic controller, etc. As another example, the terms may include one or more processors and memory and / or one or more programmable hardware elements, such as a processor, a CPU, a microcontroller, a digital signal processor, or other device capable of executing software instructions.

Claims

1. 1. An electric machine having a thermal management system, comprising: a stator having a stator core; a rotor having a rotor core and movable relative to the stator; It is equipped with at least one of the stator or the rotor of the electric machine is provided with one or more windings; one or more refrigerant cans enclosing the one or more windings of the at least one of the stator or the rotor within an internal compartment of the refrigerant can; the internal compartment defines a coolant flow path through the one or more windings; the refrigerant can has a refrigerant inlet and a refrigerant outlet in fluid communication with the interior compartment; The interior compartment of the one or more refrigerant cans is fluidly isolated from the stator core and the rotor core.

1. An electric machine characterized by:

2. the internal compartment of one or more refrigerant cans is fluidly isolated from the internal compartment of one or more other refrigerant cans; 10. The electric machine of claim 1.

3. the one or more windings comprise concentrated windings; 10. The electric machine of claim 1.

4. the refrigerant can has an interior wall extending through the interior compartment; the inner wall defines an opening through the refrigerant can; the concentrated winding is wound around the inner wall within the inner compartment; 4. The electric machine of claim 3.

5. The opening of the refrigerant can is configured to be received by one or more of a plurality of teeth provided on the stator core.

5. The electric machine of claim 4.

6. the opening of the refrigerant can is configured to be received by one or more poles of the rotor core.

5. The electric machine of claim 4.

7. the winding is a distributed winding arranged on the stator, the stator includes a refrigerant can frame defining two or more of the refrigerant cans, the inlets and outlets of the two or more refrigerant cans being in fluid communication with each other; The stator core includes a plurality of teeth; the stator core is disposed on the refrigerant can frame such that teeth of the stator core are disposed between the two or more refrigerant cans; the distributed winding is disposed within the two or more refrigerant cans, the inlets and the outlets being in fluid communication with each other.

10. The electric machine of claim 1.

8. the refrigerant can frame includes a first end cap disposed at a first axial end of the stator and a second end cap opposite the first end cap; the first end cap having an internal compartment with an inlet, and the second end cap having an internal compartment with an outlet; the inlets of the two or more refrigerant cans whose inlets are in fluid communication with one another are in fluid communication with the interior compartment of the first end cap; the outlets of the two or more refrigerant cans whose outlets are in fluid communication with one another are in fluid communication with an interior compartment of the second end cap; 8. The electric machine of claim 7.

9. the one or more concentrated windings are toroidal; 6. The electric machine of claim 5.

10. The stator core is composed of a plurality of stator segments, One or more of the plurality of teeth of the stator core are provided on the stator segment, the opening of the refrigerant can is received by the one or more teeth of the stator segment.

10. The electric machine of claim 9.

11. the rotor includes a shaft portion having a refrigerant inlet and a refrigerant outlet; the refrigerant inlet of the stem is in fluid communication with the refrigerant inlet of the refrigerant canister, and the refrigerant outlet of the stem is in fluid communication with the refrigerant outlet of the refrigerant canister; While the rotor is rotating, the refrigerant that has flowed into the refrigerant inlet of the shaft portion passes through the refrigerant can and flows to the refrigerant outlet of the shaft portion.

7. The electric machine of claim 6.

12. the shaft having an internal compartment passing through a longitudinal axis of the shaft; While the rotor is rotating, a first portion of the volume of the refrigerant that enters the refrigerant inlet of the shaft flows through the refrigerant can and to the refrigerant outlet of the shaft, and a second portion of the volume of the refrigerant that enters the refrigerant inlet of the shaft flows through the internal compartment of the shaft and to the refrigerant outlet of the shaft.

12. The electric machine of claim 11.

13. one or more electrical components of the electric machine are disposed within the internal compartment of the shaft; 13. The electric machine of claim 12.

14. one or more refrigerant cans having a plurality of outlets; At least one of the plurality of outlets is directed toward an operating volume of the electric machine that includes the stator and the rotor.

10. The electric machine of claim 1.

15. electrical components of the electric machine are disposed within the refrigerant can within the internal compartment containing the one or more windings; 10. The electric machine of claim 1.

16. 1. An electric machine having a thermal management system, comprising: a stator having a stator core; a rotor having a rotor core and movable relative to the stator; A refrigerant pump; a controller electrically connected to the refrigerant pump and configured to control the refrigerant pump; It is equipped with at least one of the stator or the rotor of the electric machine is provided with one or more windings; one or more refrigerant cans enclose one or more of the windings disposed on the at least one of the stator or the rotor within an internal compartment of the refrigerant can; the internal compartment defines a coolant flow path through the one or more windings; the refrigerant can has a refrigerant inlet and a refrigerant outlet in fluid communication with the interior compartment; The refrigerant pump is in fluid communication with one or more refrigerant inlets of the one or more refrigerant cans.

1. An electric machine characterized by:

17. a sensor disposed within the interior compartment containing the one or more windings of the one or more refrigerant cans; the sensor is electrically connected to the controller such that the controller receives an output of the sensor; 17. The electric machine of claim 16.

18. The control unit includes a processor, a storage unit, and a memory, the processor is configured to process inputs received from the sensor and stored in the memory and predetermined thresholds stored in the memory; The control unit is configured to adjust the output of the refrigerant pump.

18. The electric machine of claim 17.

19. the sensor is configured to detect a temperature of a refrigerant flowing through the one or more refrigerant cans that enclose the one or more windings disposed on at least one of the stator and the rotor; the predetermined threshold value stored in the memory of the control unit is set so that, under a steady-state continuous operation condition, the temperature of the refrigerant flowing through the one or more refrigerant cans enclosing the one or more windings arranged on at least one of the stator and the rotor is at least 5°C lower than the temperature of the stator core or the rotor core arranged on at least one of the stator and the rotor.

20. The electric machine of claim 18.

20. The stator core is made up of a plurality of laminated thin plates, the predetermined threshold value stored in the memory of the control unit is set so that the temperature of the coolant flowing through the one or more coolant cans enclosing the one or more windings arranged in the stator under a steady continuous operating condition is at least 5°C lower than the average temperature of the laminated plates of the stator core arranged in the stator.

20. The electric machine of claim 19.

21. the rotor core is made up of a plurality of laminated thin plates, the predetermined threshold value stored in the memory of the control unit is set so that the temperature of the coolant flowing through the one or more coolant cans enclosing the one or more windings arranged on the rotor under steady-state continuous operating conditions is at least 5°C lower than the average temperature of the laminated thin plates of the rotor core arranged on the rotor.

20. The electric machine of claim 19.

22. 1. A method for thermal management of an electric machine having a thermal management system, comprising: flowing a refrigerant through an internal compartment of one or more refrigerant cans, wherein the refrigerant cans enclose one or more windings of the electric machine within the internal compartment of the refrigerant can, and the internal compartment of the refrigerant can is fluidly isolated from other components of the electric machine. A method characterized by:

23. Detecting a temperature of the one or more windings enclosed in the one or more refrigerant cans; determining whether the detected temperature exceeds a threshold; flowing additional refrigerant into the interior compartment of the one or more refrigerant canisters in response to determining that the sensed temperature exceeds the threshold; 23. The method of claim 22, further comprising:

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