Patent ID: 12238907

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

An example of a PHEV is depicted inFIG.1and referred to generally as a vehicle16. The vehicle16includes a transmission12and is propelled by at least one electric machine18with selective assistance from an internal combustion engine20. The electric machine18may be an alternating current (AC) electric motor depicted as “motor”18inFIG.1. The electric machine18receives electrical power and provides torque for vehicle propulsion. The electric machine18also functions as a generator for converting mechanical power into electrical power through regenerative braking.

The transmission12may be a power-split configuration. The transmission12includes the first electric machine18and a second electric machine24. The second electric machine24may be an AC electric motor depicted as “generator”24inFIG.1. Like the first electric machine18, the second electric machine24receives electrical power and provides output torque. The second electric machine24also functions as a generator for converting mechanical power into electrical power and optimizing power flow through the transmission12. In other embodiments, the transmission does not have a power-split configuration.

The transmission12may include a planetary gear unit26, which includes a sun gear28, a planet carrier30, and a ring gear32. The sun gear28is connected to an output shaft of the second electric machine24for receiving generator torque. The planet carrier30is connected to an output shaft of the engine20for receiving engine torque. The planetary gear unit26combines the generator torque and the engine torque and provides a combined output torque about the ring gear32. The planetary gear unit26functions as a continuously variable transmission, without any fixed or “step” ratios.

The transmission12may also include a one-way clutch (O.W.C.) and a generator brake33. The O.W.C. is coupled to the output shaft of the engine20to only allow the output shaft to rotate in one direction. The O.W.C. prevents the transmission12from back-driving the engine20. The generator brake33is coupled to the output shaft of the second electric machine24. The generator brake33may be activated to “brake” or prevent rotation of the output shaft of the second electric machine24and of the sun gear28. Alternatively, the O.W.C. and the generator brake33may be eliminated and replaced by control strategies for the engine20and the second electric machine24.

The transmission12may further include a countershaft having intermediate gears including a first gear34, a second gear36and a third gear38. A planetary output gear40is connected to the ring gear32. The planetary output gear40meshes with the first gear34for transferring torque between the planetary gear unit26and the countershaft. An output gear42is connected to an output shaft of the first electric machine18. The output gear42meshes with the second gear36for transferring torque between the first electric machine18and the countershaft. A transmission output gear44is connected to a driveshaft46. The driveshaft46is coupled to a pair of driven wheels48through a differential50. The transmission output gear44meshes with the third gear38for transferring torque between the transmission12and the driven wheels48.

The vehicle16includes an energy storage device, such as a traction battery52for storing electrical energy. The battery52is a high-voltage battery that is capable of outputting electrical power to operate the first electric machine18and the second electric machine24. The battery52also receives electrical power from the first electric machine18and the second electric machine24when they are operating as generators. The battery52is a battery pack made up of several battery modules (not shown), where each battery module contains a plurality of battery cells (not shown). Other embodiments of the vehicle16contemplate different types of energy storage devices, such as capacitors and fuel cells (not shown) that supplement or replace the battery52. A high-voltage bus electrically connects the battery52to the first electric machine18and to the second electric machine24.

The vehicle includes a battery energy control module (BECM)54for controlling the battery52. The BECM54receives input that is indicative of vehicle conditions and battery conditions, such as battery temperature, voltage and current. The BECM54calculates and estimates battery parameters, such as battery state of charge and the battery power capability. The BECM54provides output (BSOC, Pcap) that is indicative of a battery state of charge (BSOC) and a battery power capability (Pcap) to other vehicle systems and controllers.

The vehicle16includes a DC-DC converter or variable voltage converter (VVC)10and an inverter56. The VVC10and the inverter56are electrically connected between the traction battery52and the first electric machine18, and between the battery52and the second electric machine24. The VVC10“boosts” or increases the voltage potential of the electrical power provided by the battery52. The VVC10also “bucks” or decreases the voltage potential of the electrical power provided to the battery52, according to one or more embodiments. The inverter56inverts the DC power supplied by the battery52(through the VVC10) to AC power for operating the electric machines18,24. The inverter56also rectifies AC power provided by the electric machines18,24, to DC for charging the traction battery52. Other embodiments of the transmission12include multiple inverters (not shown), such as one invertor associated with each electric machine18,24. The VVC10includes an inductor assembly14.

The transmission12includes a transmission control module (TCM)58for controlling the electric machines18,24, the VVC10and the inverter56. The TCM58is configured to monitor, among other things, the position, speed, and power consumption of the electric machines18,24. The TCM58also monitors electrical parameters (e.g., voltage and current) at various locations within the VVC10and the inverter56. The TCM58provides output signals corresponding to this information to other vehicle systems.

The vehicle16includes a vehicle system controller (VSC)60that communicates with other vehicle systems and controllers for coordinating their function. Although it is shown as a single controller, the VSC60may include multiple controllers that may be used to control multiple vehicle systems according to an overall vehicle control logic, or software.

The vehicle controllers, including the VSC60and the TCM58generally includes any number of microprocessors, ASICs, ICs, memory (e.g., FLASH, ROM, RAM, EPROM and/or EEPROM) and software code to co-act with one another to perform a series of operations. The controllers also include predetermined data, or “look up tables” that are based on calculations and test data and stored within the memory. The VSC60communicates with other vehicle systems and controllers (e.g., the BECM54and the TCM58) over one or more wired or wireless vehicle connections using common bus protocols (e.g., CAN and LIN). The VSC60receives input (PRND) that represents a current position of the transmission12(e.g., park, reverse, neutral or drive). The VSC60also receives input (APP) that represents an accelerator pedal position. The VSC60provides output that represents a desired wheel torque, desired engine speed, and generator brake command to the TCM58; and contactor control to the BECM54.

The vehicle16includes an engine control module (ECM)64for controlling the engine20. The VSC60provides output (desired engine torque) to the ECM64that is based on a number of input signals including APP, and corresponds to a driver's request for vehicle propulsion.

If the vehicle16is a PHEV, the battery52may periodically receive AC energy from an external power supply or grid, via a charge port66. The vehicle16also includes an on-board charger68, which receives the AC energy from the charge port66. The charger68is an AC/DC converter which converts the received AC energy into DC energy suitable for charging the battery52. In turn, the charger68supplies the DC energy to the battery52during recharging. Although illustrated and described in the context of a PHEV16, it is understood that the inverter56may be implemented on other types of electric vehicles, such as a HEV or a BEV.

Referring toFIG.2, an electrical schematic of the VVC10and the power module assembly57of the power inverter56is shown. The VVC10may include a one or more cards having at least a first switching unit70and a second switching unit72for boosting the input voltage (Vbat) to provide output voltage (Vdc). The first switching unit70may include a first transistor74connected in parallel to a first diode76, but with their polarities switched (anti-parallel). In one embodiment the switch70may be a reverse conducting insulated gate bipolar transistor (RCIGBT). The second switching unit72may include a second transistor78connected anti-parallel to a second diode80. Each transistor74,78may be any type of controllable switch (e.g., an insulated gate bipolar transistor (IGBT) or field-effect transistor (FET)). Additionally, each transistor74,78may be individually controlled by the TCM58. The inductor assembly14is depicted as an input inductor that is connected in series between the traction battery52and the switching units70,72. The inductor14generates magnetic flux when a current is supplied. When the current flowing through the inductor14changes, a time-varying magnetic field is created, and a voltage is induced. Other embodiments of the VVC10include alternative circuit configurations.

The power module assembly57may include a plurality of cards (also known as power modules). Each of the cards may include one or more half bridges82having a positive DC lead84that is coupled to a positive DC node from the battery and a negative DC lead86that is coupled to a negative DC node from the battery. Each of the half bridges82may also include a first switching unit88and a second switching unit90. The first switching unit88may include a first transistor92connected in parallel to a first diode94. The second switching unit90may include a second transistor96connected in parallel to a second diode98. The first and second transistors88,96may be IGBTs or FETs. The first and second switching units88,90may be similar to the switching units70,72. The first and second switching units of the each of the half-bridges82convert the DC power of the battery into a single phase AC output at the AC lead100. Each of the AC leads100are electrically connected to the motor18or generator24.

The vehicle power inverter may be mounted on a vehicle component, such as a body structure, frame member, or powertrain component. The power inverter may include a power module assembly that is electrically connected with a gate drive board, a capacitor bank, and a control board. The power-module assembly may include a plurality of cards (also known as power modules) each having one or more half bridges packaged therein.

FIGS.3to10and the related discussion describe example power module assemblies. Referring toFIGS.3through9, an example power module assembly120includes a housing122that supports a plurality of cards126that are liquid cooled within the housing via direct contact between the cards126and the coolant. This direct contact increases the thermal efficiency of the system. The coolant is

FIGS.4and5and the associated text describe an example card (or power module)126for a power module assembly (such as power module assembly120). The card126may include a first substrate352and a second substrate354that sandwich a plurality of switching units356. The first substrate352includes an outer panel358, an inner panel360, and a dielectric layer362disposed between the inner and outer panels. The outer panel358defines an outer major side of the card, the inner panel360defines an inner major side of the substrate, and the thin edges of the panels and dielectric layer collectively define a portion of the minor sides of the card. The panels and dielectric layer are bonded together by a high-temperature oxidation process for example. The inner and outer panels358,360may be metal such as copper, aluminum, silver, or gold. In one embodiment, the outer panel358is unpatterned copper and the inner panel368is patterned copper. The term “patterned” refers to a panel that has been etched to define an electrical circuit. The dielectric layer362may be ceramic. Example ceramics include alumina, aluminum nitride, and silicon nitride. In some embodiments, the ceramics may be doped. The second substrate354also includes an outer panel364, in inner panel366, and a dielectric layer362. The materials of the inner and outer panels and the dielectric layer maybe similar to that described above with respect to the first substrate352.

The card126includes one or more switching units356(also known as chips or dies), such as six switching units shown in the illustrated embodiment ofFIG.6. Each of the switching units356includes a transistor370and a diode372. The transistor370may be, but is not limited to, IGBTs or FETs. Each of the switching units356is electrically connected to one or both of the inner panel360and/or the inner panel366. The card126includes a plurality of shims378that electrically connect the switching units356to one of the inner panels and act as spacing features. A mold compound380encapsulates the internal components of the card126.

The card126also includes a plurality of terminals376and signal pins374. For example, the card126may include a positive DC terminal382, a negative DC terminal384, a generator AC terminal386, and a motor AC terminal388. The DC terminals382,384are electrically connected with the capacitor bank and the traction battery. The AC terminals386,388are electrically connected to an associated electric machine. The signal pins374are electrically connected to the gate drive board. The terminals and pins may be formed by a patterned inner panel or may be separate components attached to the switching units356. The embodiment shown inFIGS.5and6is merely one example in this application is not limited to any particular card design.

Referring toFIGS.6and7, each card126may include an outer frame or border124, which may be injection molded with the electronic components of the card. Each card126may further include a first major side132(coinciding with substrate358), a second major side134(coinciding with the substrate364), a first pair of minor sides135,136and second pair of minor sides137and138. The terminals and pins may extend through the frame124at the minor sides135,136. These minor sides may also include compression limiters140that protect the electrical components when the housing is assembled. In the illustrated embodiment, the compression limiters140are projections extending outwardly from the minor sides. These projections may be integrally formed with the frame124.

The cards126may include features that are received in adjacent ones of the cards for connection and/or location purposes when the cards are assembled into an array as will be described in more detail below. For example, the minor sides137may include one or more projections142, e.g., pegs, that are sized to be received in one or more receptacles144, e.g., holes. In the illustrated embodiment, the projections and the receptacles are arranged in pairs to ensure proper orientation of the cards126relative to each other when assembled into the array. In some embodiments, these features are for locating purposes and do not include any retaining mechanism. In other embodiments, these features are used to retain the cards to each other, such as via snap fit, click fit, interference fit, or the like.

The frame124may be raised on the minor sides135and136in order to project upwardly (or downwardly) from the major sides132,134. That is, the card126may have a generally H-shape cross-section when viewed from a side looking at the minor side138. The raised frame portions may be used for sealing purposes with the housing as will be explained in more detail below. In the illustrated example, the card126includes four sealing ledges148(a-d). The sealing ledges148aand148bproject outwardly from the major side132, and the sealing ledges148aand148bproject outwardly from the major side134. Each of the sealing ledges148may include a sealing surface150.

Referring toFIGS.3,8, and9, the housing122includes a cover152and a tray154. The terms “tray” and “cover” are for ease of description and do not imply any particular structure nor that the “tray” and “cover” are different nor that the tray is on the bottom and the cover is on top. The tray and cover may be identical halves of the housing (as shown) or may differ in size, shape, etc., in other embodiments. The cover152may have a generally elongated shape with a panel160(e.g., a top) and sidewalls162extending downwardly from the panel160. The sidewalls162and the panel160define recessed area. The tray154may have a generally elongated shape with a panel164(e.g., a bottom) and sidewalls166extending upwardly from the panel164. The sidewalls166and the panel164define another recessed area. When the housing is assembled, with the cover152received on the tray154, the recessed areas cooperate to define a cavity168within the housing152. The tray154may define a first recessed seat172surrounding the cavity168, and the cover152may define a second recessed seat174surrounding the cavity168.

The cards126may be arranged in a side-by-side planar, linear array170that is supported in the cavity168. The cards126are arranged in the array such that the minor sides137and138abut adjacent minor sides of the next card with the projections142received in the receptacles144. This places the sealing ledges148in alignment creating continuous raised rails178extending along the longitudinal direction of the array170. The raised rails define sealing surfaces179. The array170is suspended within the cavity168by these raised rails178. For example, the sealing ledges148aand148bare at least partially received in the sealing seat174of the cover152, and the sealing ledges148cand148dare at least partially received in the sealing seat172of the tray154. A first seal or gasket180is received within the seat174and sealingly engages with the sealing ledges148aand148b. A second seal or gasket182is received within the seat172and sealingly engages with the sealing ledges148cand148d.

An inlet manifold184is defined between a first longitudinal side188of the array and the cover152and an outlet manifold186is defined between a second longitudinal side190of the array and the tray154. The cover152may define an inlet port192that opens into the inlet manifold184. The tray154may define an outlet port194that opens into the outlet manifold. The placement of the inlet/outlet ports may be switched in other embodiments. The manifolds and the ports are in fluid communication and collectively form a fluid path196that is in direct contact with the cards126. Having the liquid coolant in direct contact with the cards126reduces the thermal resistance of the cooling system compared to cold plate and cooling fin designs by eliminating the thermal resistance of the cold-plate top or the fins. This creates a more efficient heat transfer between the cards and the coolant compared to traditional designs.

Fluid control components may be attached to the ends of the array170. For example, a separator200may be attached to one end of the array178and a return guide202may be attached to the other end of the array. The separator200may include pins203that are received within the receptacles144of the first card of the array178. (Other types of the connections are also contemplated.) The return guide202may define receptacles205that received the projections142of the last card of the array178. The pins and the receptacles are merely one example of locating and connecting features and others are contemplated as discussed above with regards to the locating and connecting features of the cards.

The separator200may be a planar component having a thickness that generally matches the array. For example, the separator may have a main face204that is coplanar with the major sides132,134of the cards126and raised rims206/208that are the same or similar height as the ledges148. The raised rim206may be received in the sealing seat174of the cover and engages with the gasket180. Similarly, the raised rim208may is received in the sealing seat176of the tray and engages with the gasket182. The separator200is placed between the inlet port192and the outlet port194, which are aligned with each other, e.g., concentric about a common centerline extending through the ports.

The return guide202is configured to redirect the coolant from the inlet manifold172the outlet manifold186. The return guide202may include raised rims210,212that are received in the sealing seats174and176and sealingly engage with the gaskets180and182like the separator. The central portion214of the return guide202is spaced apart from the minor side137of the last card126so that fluid can pass through the assembly at that end. The central portion may be curved, e.g., C-shaped, to facilitate the redirecting of coolant.

The upper surface of the main face204directs fluid entering through the inlet port192to the inlet manifold170. From there, the fluid path196flows across the upper longitudinal side of the array178within the inlet manifold170. The inlet manifold184may include a plurality of flow guides216, which may be an integrally formed portion of the cover152. The fluid path travels downwardly at the return guide202from the inlet manifold184to the outlet manifold186. The outlet manifold186may also include flow guides218. The flow path196extends through the outlet manifold186in a direction that is opposite to the inlet manifold184. Coolant then exits the outlet manifold186via the outlet port194. The vehicle may include a coolant circulation system including a pump and one or more heat exchangers for dissipating the heat from the power module assembly120.

The housing122is watertight to prevent coolant from leaking from the power module assembly120. As discussed above, seals or gaskets180,182are utilized to seal the part line between the tray154and the cover152. Secondary seals or gaskets (not shown) may also be used to assist the main seals. The secondary seals may be inside the main seals, e.g., gaskets180,182.

When the housing122is fully assembled, the cover152is spaced slightly from the tray154creating a gap for the pins and terminals of the cards126to extend therethrough. This gap is created by the compression limiters140, which on one side are in contact with the tray154and on the other side are in contact with the cover152.

FIG.10illustrates another power module assembly250according to one or more alternative embodiments. Common components will not be discussed again for brevity; please see above for their description.FIG.10showcases the modularity of the components of the power module assembly for placement in different vehicles with different packaging constraints. In this embodiment, the tray252has both the inlet and the outlet ports for the fluid path254. In one or more embodiments, the tray252is the same component as the above-described tray154but the separator256is different to create the inlet and outlet ports through the tray. For example, the separator256includes a neck258that extends through the hole260(which was the outlet port194). The neck258defines a pair of channels. One of the channels forms an inlet port262and the other of the channels forms an outlet port264. The inlet channel262extends completely through the separator256and is in communication with the inlet manifold266. The outlet channel264does not extend completely through the separator so that it is in fluid communication with the outlet manifold270. The cover272may be the same component as the above-described cover152and a274is used to plug the hole276that is not being used in this implementation.

While example embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to strength, durability, life cycle, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications