Electrified vehicle thermal management system and thermal management method

An electrified vehicle thermal management system includes, among other things, a transmission, an inverter, and a terminal block disposed between the transmission and the inverter. The terminal block includes a conduit configured to deliver transmission fluid from the transmission to the inverter. An electrified vehicle thermal management method includes circulating a transmission fluid between a transmission, a terminal block, and an inverter, and using the transmission fluid to manage thermal energy within the inverter.

TECHNICAL FIELD

This disclosure relates generally to managing thermal energy in areas of an electrified vehicle and, more particularly, to using transmission fluid to manage thermal energy in an inverter.

BACKGROUND

Electrified vehicles differ from conventional motor vehicles because electrified vehicles are selectively driven using one or more electric machines powered by a traction battery pack. The electric machines can drive the electrified vehicles instead of, or in addition to, an internal combustion engine. Example electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

SUMMARY

An electrified vehicle thermal management system according to an exemplary aspect of the present disclosure includes, among other things, a transmission, an inverter, and a terminal block disposed between the transmission and the inverter. The terminal block includes a conduit configured to deliver transmission fluid from the transmission to the inverter.

In another example of the foregoing system, the conduit is a first conduit. The terminal block includes a second conduit configured to deliver transmission fluid from the inverter to the transmission.

Another example of any of the foregoing systems includes a plurality of terminal block busbars of the terminal block. The second conduit is configured to communicate transmission fluid that is received from the inverter adjacent to the plurality of terminal block busbars to manage thermal energy within the plurality of terminal block busbars.

Another example of any of the foregoing systems includes a plurality of inverter busbars of the inverter. The first conduit is configured to deliver transmission fluid to the inverter. The transmission fluid manages thermal energy levels within the plurality of inverter busbars.

In another example of any of the foregoing systems, the plurality of terminal block busbars that electrically couple the inverter to a motor within the transmission.

Another example of any of the foregoing systems includes a pump configured to circulate transmission fluid from the transmission through a first conduit in the terminal block to the inverter, and from the inverter through a second conduit in the terminal block to the transmission.

In another example of any of the foregoing systems, the pump draws the transmission fluid from a sump within the transmission.

In another example of any of the foregoing systems, the pump communicates the transmission fluid from the sump to a radiator that is configured to transfer thermal energy from the transmission fluid to air.

In another example of any of the foregoing systems, the pump communicates the transmission fluid from the radiator through a conduit in terminal block and then to the inverter.

Another example of any of the foregoing systems includes plurality of busbars of the inverter. The plurality of busbars are each configured such that the busbars include a portion disposed at an interface between the terminal block and the inverter.

In another example of any of the foregoing systems, the inverter is an inverter system controller of an electrified vehicle.

Another example of any of the foregoing systems includes a radiator that is configured to transfer thermal energy from the transmission fluid to air.

Another example of any of the foregoing systems includes a plurality of busbars within the inverter and outside the transmission. The busbars cooled by transmission fluid that is circulated outside the transmission.

In another example of any of the foregoing systems, the transmission is a transmission of an electrified vehicle.

In another example of any of the foregoing systems, the terminal block is secured directly to the transmission. The inverter is secured directly to the terminal block.

An electrified vehicle thermal management method according to another exemplary aspect of the present disclosure includes circulating a transmission fluid between a transmission, a terminal block, and an inverter, and using the transmission fluid to manage thermal energy within the inverter.

Another example of the foregoing method includes communicating the transmission fluid from the transmission through a conduit in a terminal block and then to the inverter.

Another example of any of foregoing methods includes using the transmission fluid to manage thermal energy within busbars of the inverter.

Another example of any of foregoing methods includes circulating the transmission fluid from the inverter through another conduit in the terminal block and then back to the transmission.

Another example of any of foregoing methods includes using the transmission fluid to manage thermal energy within busbars of the terminal block.

DETAILED DESCRIPTION

This disclosure details a system and method that uses transmission fluid to manage thermal energy within an inverter of an electrified vehicle. The transmission fluid can move to and from the inverter through conduits within a high-voltage alternating current (HVAC) terminal block, which can be sandwiched between an inverter and a transmission block of the electrified vehicle.

FIG. 1schematically illustrates selected portions of a powertrain10of an electrified vehicle. Although depicted as a hybrid electrified vehicle (HEV), it should be understood that the concepts described herein are not limited to HEVs and could extend to other electrified vehicles, including, but not limited to, plug-in hybrid electrified vehicles (PHEVs), fuel cell vehicles (FCVs), and battery electrified vehicles (BEVs).

In an embodiment, the powertrain10is a powersplit powertrain system that employs a first drive system and a second drive system. The first drive system includes a combination of an engine12and a generator14(i.e., a first electric machine). The second drive system includes at least a motor16(i.e., a second electric machine), the generator14, and at least one traction battery pack18. In this example, the second drive system is considered an electric drive system of the powertrain10. The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels20of the electrified vehicle. Although a power-split configuration is depicted inFIG. 1, the teachings of this disclosure extend to any hybrid or electric vehicle including full hybrids, parallel hybrids, series hybrids, mild hybrids or micro hybrids.

The engine12, which is an internal combustion engine in this example, and the generator14may be connected through a power transfer unit22. In one non-limiting embodiment, the power transfer unit22is a planetary gear set that includes a ring gear24, a sun gear26, and a carrier assembly28. Of course, other types of power transfer units, including other gear sets and transmissions, may be used to connect the engine12to the generator14.

The generator14can be driven by engine12through the power transfer unit22to convert kinetic energy to electrical energy. The generator14can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft30connected to the power transfer unit22. Because the generator14is operatively connected to the engine12, the speed of the engine12can be controlled by the generator14.

The ring gear24of the power transfer unit22may be connected to a shaft32, which is connected to vehicle drive wheels20through a second power transfer unit34. The second power transfer unit34may include a gear set having a plurality of gears36. Other power transfer units may also be suitable. The gears36transfer torque from the engine12to a differential38to ultimately provide traction to the vehicle drive wheels20. The differential38may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels20. In this example, the second power transfer unit34is mechanically coupled to an axle40through the differential38to distribute torque to the vehicle drive wheels20.

The motor16(i.e., the second electric machine) can also be employed to drive the vehicle drive wheels20by outputting torque to a shaft42that is also connected to the second power transfer unit34. In one embodiment, the motor16and the generator14cooperate as part of a regenerative braking system in which both the motor16and the generator14can be employed as generators to output electrical energy. For example, the motor16and the generator14can each output electrical power to the traction battery pack18.

A transmission46of the exemplary powertrain10includes the power transfer unit22, the gears36, the motor16, and the generator14. The transmission46can transmit power from the engine12to the differential38.

The traction battery pack18has the form of a high-voltage battery that is capable of outputting electrical power to operate the motor16and the generator14within the transmission46. The traction battery pack18is a traction battery as it provides power to drive the vehicle drive wheels20.

The powertrain10may additionally include an inverter system, which may also be referred to as an inverter system controller (ISC)48. The ISC48is adapted to support bidirectional power flow through the powertrain10. For example, the ISC48can convert DC power derived from the traction battery pack18to AC power for driving the motor16, the generator14, or both. The ISC48can be combined with a variable voltage converter (ISC/VVC). In the exemplary embodiment, the ISC48is outside the transmission46. In other examples, portions of the ISC48, such as an inductor of the ISC48can be at least partially disposed within a housing of the transmission46.

Transmission fluid can manage thermal energy within the transmission46. Exemplary electrified vehicle thermal management systems and methods of this disclosure utilize transmission fluid to additionally manage thermal energy in other areas of the powertrain10that are not part of the transmission, such as thermal energy within the ISC48.

Managing thermal energy, for purposes of this disclosure can include removing thermal energy to lower a temperature of a component, adding thermal energy to raise a temperature of a component, or maintaining a temperature of a component.

With reference toFIG. 2, a terminal block50is adjacent the transmission46and the ISC48. In particular, the ISC48is secured directly to the terminal block50, which is secured directly to the transmission46. The ISC48can be secured to the terminal block50using mechanical fasteners, for example. The terminal block50can be secured to the transmission46using mechanical fasteners, for example. In the exemplary embodiment, the terminal block50is a High Voltage Alternating Current (HVAC) terminal block.

The terminal block50can electrically couple the motor16to the ISC48in order to output AC power for driving the motor16. For example, the ISC48may receive DC power from the traction battery pack18(FIG. 1), and may convert this DC power to three-phase AC power. The AC power is carried to the motor16by the terminal block50for driving the motor16.

The terminal block50includes a plurality of busbars52for electrically coupling the ISC48and the motor16. The busbars52can be operatively coupled to current sensors. Reducing thermal energy within the busbars52can help to avoid raising a temperature of the current sensors to an undesirable level. The current sensors can envelope portions of the busbars52. Cooling the busbars52can cool the associated current sensors.

In this example, the terminal block50includes four busbars52. However, the total number of busbars52is not intended to limit this disclosure. That is, a greater or fewer number of busbars52than are shown in theFIG. 2could be employed within the terminal block50.

In a non-limiting embodiment, the busbars52are made of copper. However, other materials may also be suitable. The busbars52can electrically connect motor stator leads, which can be connected to windings of the motor16, to current sensors.

Through the busbars52, the terminal block50electrically couples at least the motor16within the transmission46to the ISC48. However, the terminal block50of this disclosure could be used to electrically couple any electrified vehicle components that operate over an AC or a DC bus.

In this example, the ISC48includes a plurality of busbars56. The busbars56can be housed within the capacitor housing and can be secured by potting material within the capacitor housing. The busbars56are considered DC link busbars or input busbars in some examples. The busbars52, in contrast to the busbars56, can be considered AC busbars, output busbars, or inductor busbars.

A thermal management system of the powertrain10is used to manage thermal energy levels in the transmission46, the ISC48, and terminal block. The thermal management system includes transmission fluid that can move along a circuit60through areas of the transmission46, the terminal block50, and the ISC48. In this example, a pump62communicates the transmission fluid along the circuit60.

Along the circuit60, transmission fluid moves from a sump64within the transmission46to a radiator66. The radiator66is a fluid-to-air heat exchanger. At the radiator66, thermal energy within the transmission fluid is transferred to air. Thus, transmission fluid moving away from the radiator66is cooler than the transmission fluid entering the radiator.

Transmission fluid that has been cooled at the radiator66moves to the transmission46. The transmission46includes a transmission conduit80that communicates the transmission fluid to the terminal block50. The terminal block50includes a first terminal block conduit82that communicates the transmission fluid received from the terminal block50to the ISC48.

The transmission fluid moving along the path P within the ISC48can manage thermal energy of components of the ISC48. For example, the transmission fluid exiting the first terminal block conduit82moves through areas of the ISC48to cool the busbars

In this example, the transmission fluid cools, in particular, busbars56of the ISC48. In the exemplary embodiment, although the transmission fluid moves along path P through the transmission46and terminal block50before reaching the busbars56, the busbars56are substantially the first component that is cooled by the transmission fluid.

Transmission fluid that has taken on thermal energy from the busbars56moves along the path P back to the terminal block50. The transmission fluid then takes on more thermal energy from the busbars52within the terminal block50.

The transmission fluid then moves from the terminal block50to the sump64. The terminal block50includes a second terminal block conduit84that communicates the transmission fluid received from the terminal block50to the ISC48.

The transmission fluid within the transmission46may, prior to moving to the sump64, take on thermal energy from various components of the transmission46to manage thermal energy within these components. For example, transmission fluid exiting the terminal block50can move through areas of the motor16, areas of the generator14, gear sets/bearings, or some combination of these components within the transmission46. After transferring thermal energy away from these components, the fluid moves to the sump64. The pump62can then draw the fluid from the sump64to cool the fluid at the radiator66.

FIG. 3shows a bottom view of the ISC48according to an exemplary aspect of the present disclosure. Transmission fluid enters the ISC48from the first terminal block conduit82at an ISC inlet100. The fluid then moves through a chamber104to take on thermal energy from the busbars56along with other components of the ISC48, such as capacitor cells. The fluid then moves through an ISC outlet112to the terminal block50.

FIGS. 4-6illustrate an ISC48A according to another exemplary embodiment of the present disclosure. The ISC48A includes busbars56P associated with positive capacitor terminals and busbars56N associated with negative capacitor terminals. The busbars56P and56N are configured such that the busbars56P and56N include a portion disposed at an interface between the terminal block50and the ISC48A. In the example, the busbars56P and56N each include substantial areas extending along a side116of the ISC48A, which is the side interfacing with the HVAC terminal block50(FIG. 2). The side116is a bottom side of the ISC48A in this example.

Portions of the busbars56P and56N can extend between capacitors cells120of the ISC48A. The busbars56P and56N are configured such that both P and N terminals are exposed to transmission fluid running along the bottom side116, which faces the transmission46.

The busbars56P and56N are copper in this example. Where required, insulation124can be used to electrically isolate the busbars56P and56N from each other. Potting resin128can be disposed about the busbars56P,56N, the capacitor cells120and the insulation124.

A chamber104A can be configured such that the path P of the transmission fluid within the chamber104A follows along the side116of the ISC48A. Thermal transfer from the busbars56P and56N is enhanced as substantial areas of the busbars56P and56N extend along the bottom side116of the ISC48A.

The configuration of the ISC48A facilitates thermal energy transferred from the busbars56P and56N to the transmission fluid by helping to maximize surface area of the busbars56P and56N exposed to the transmission fluid moving within the chamber104A. In this example, boundaries of the chamber104can be delineated by the busbars56P,56N, a housing of the capacitor cells120, and the terminal block50.

Referring toFIG. 7with reference again toFIG. 3, transmission fluid that has moved through the outlet112moves into the terminal block50through an inlet130in the terminal block50to a chamber134. From the chamber134, the fluid can flow along the individual busbars52to take on thermal energy from the busbars52. The transmission fluid then moves from the terminal block50through one or more outlets138to the transmission46(FIG. 2). The transmission fluid can then take on thermal energy from various components of transmission46before collecting in the sump64.

Some features of the disclosed examples include an ISC that requires relatively less packaging space than other ISC designs. Among other things, thermal management can facilitate reducing a size of capacitor cells and current sensors, which can lead to a reduced ISC packaging envelope.

Another feature is enhanced thermal management efficiency, which can improve thermal performance for capacitors and current sensors, and improve overall ISC reliability and durability.

Another feature is that a thermal management fluid other than the transmission fluid may not be required to manage thermal energy within the ISC, which can reduce complexity. For certain current sensors of the ISC, such a giant magnetoresistance current sensor, the accuracy of the sensor can decrease at higher temperature.

Yet another feature of this disclosure is keeping the current sensor cooled, which can improve overall current sensor accuracy over operating range.