Patent Description:
In a vehicle, especially an electric vehicle and a hybrid vehicle, in order to ensure the driving range, the service life, and the available power of the electric vehicle and the hybrid vehicle, it is necessary to manage the temperature of the power battery of the vehicle, so that the power battery always operate at a suitable temperature. In the related art, a battery heat exchange circuit is provided for heating the battery pack, and a PTC for heating a cooling liquid, a water pump for promoting circulation of the cooling liquid, and a heat exchanger provided at the battery pack for heat exchange with the battery pack are provided in the battery heat exchange circuit. The cooling liquid in the circuit is heated by the PTC in the circuit, and then the battery is heated. The battery is cooled by the heat exchange between the cooling liquid in the heat exchanger at the battery package and a refrigerant in an air conditioning system. When the battery is cooled, the PTC in the circuit is turned off. Such a thermal management system for the battery pack is completed by an additionally designed battery heat exchange circuit, which has complex pipeline arrangement, a more parts and components, and higher costs.

Document <CIT> discloses a thermal management system comprising a refrigerant circuit and a coolant circuit for a high-voltage system.

The present invention is intended to provide a vehicle thermal management system, which can simplify pipelines arrangement for cooling and heating a battery pack and reduce the cost.

In order to achieve the above object, the present invention provides a vehicle thermal management system, including a first thermal management system and a second thermal management system for a high-voltage system. The second thermal management system includes a heat sink, a heat exchanger, and a waste heat utilization branch. The waste heat utilization branch is provided with a water pump and a high-voltage system cooling branch passing through the high-voltage system that are interconnected. A cooling liquid outlet of the heat exchanger communicates with an inlet of the waste heat utilization branch, and an outlet of the waste heat utilization branch optionally communicates directly with a cooling liquid inlet of the heat exchanger or via the heat sink with the cooling liquid inlet of the heat exchanger.

The first thermal management system includes a compressor and a battery pack provided with a direct-cooling device. An outlet of the compressor communicates with a first port of the direct-cooling device of the battery pack, a second port of the direct-cooling device of the battery pack communicates with a refrigerant inlet of the heat exchanger via a first throttle branch, and a refrigerant outlet of the heat exchanger communicates with an inlet of the compressor.

According to the above technical solutions, at least the following technical effects can be achieved.

Since the battery pack is provided with a direct-cooling device, the heat exchange between the refrigerant and the battery pack is completed through the direct-cooling device. Therefore, it is unnecessary to arrange, on the battery pack, an additional heat exchanger and pipelines communicating with the additional heat exchanger for cooling the battery pack, which simplifies the pipeline arrangement for heating and cooling the battery pack and reduces the cost. The refrigerant is directly used to exchange heat for the battery pack, which has high heat exchange efficiency and is not affected by the external environment. No matter in a high-temperature or low-temperature environment, the battery pack can operate within a suitable temperature range, which improves the charging and discharging efficiency of the battery pack, improves the endurance, extends the service life of the battery pack, and ensures the safety of the battery pack.

According to another aspect of the present invention, an electric vehicle is provided, including the vehicle thermal management system described in any of the above.

Other features and advantages of the present invention are to be described in detail in the following part of detailed description.

The accompanying drawings are intended to provide further understanding of the present invention and constitute a part of this specification. The accompanying drawings and the specific implementations below are used together for explaining the present invention rather than constituting a limitation on the present invention. In the accompanying drawings:.

Specific implementations of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific implementations described herein are merely used to describe and explain the present invention, but are not intended to limit the present invention.

In the present invention, unless stated to the contrary, directional words such as "upstream and downstream" are used relative to a flow direction of a refrigerant. Specifically, the flow direction towards the refrigerant is downstream, and the flow direction away from the refrigerant is upstream. "Inside and outside" mean inside and outside of a contour of a corresponding component.

In the present invention, an electric vehicle may include a pure electric vehicle, a hybrid vehicle, and a fuel cell vehicle. <FIG> is a schematic structural diagram of a vehicle thermal management system <NUM> according to an implementation of the present invention. As shown in <FIG>, the system may include a heating ventilation and air conditioning (HVAC) assembly and a damper mechanism (not shown). The damper mechanism includes an air duct that may be used to conduct air an in-vehicle evaporator <NUM> and an in-vehicle condenser <NUM>.

In order to simplify the pipeline for cooling and heating a battery pack <NUM>, in an implementation of the present invention, as shown in <FIG>, a vehicle thermal management system <NUM> is provided, including a first thermal management system <NUM> and a second thermal management system <NUM> for a high-voltage system. The second thermal management system <NUM> includes a heat sink <NUM>, a heat exchanger <NUM>, and a waste heat utilization branch <NUM> (shown by dashed arrows in <FIG>). A water pump <NUM> and a high-voltage system cooling branch <NUM> passing through the high-voltage system that are interconnected with each other are arranged on the waste heat utilization branch <NUM>. A cooling liquid outlet of the heat exchanger <NUM> communicates with an inlet of the waste heat utilization branch <NUM>, an outlet of the waste heat utilization branch <NUM> optionally communicates directly with a cooling liquid inlet of the heat exchanger <NUM> through a fourth flow branch <NUM> or with the cooling liquid inlet of the heat exchanger <NUM> through the heat sink <NUM>. The water pump <NUM> arranged on the waste heat utilization branch <NUM> provides circulating power for the whole second thermal management system <NUM>. The second thermal management system <NUM> further includes a reversing valve <NUM>. Through the reversing valve <NUM>, the outlet of the waste heat utilization branch <NUM> optionally communicates directly with the cooling liquid inlet of the heat exchanger <NUM> or with the cooling liquid inlet of the heat exchanger <NUM> through the heat sink <NUM>.

The first thermal management system <NUM> includes a compressor <NUM> and a battery pack <NUM> provided with a direct-cooling device. An outlet of the compressor <NUM> communicates with a first port <NUM> of the direct-cooling device of the battery pack <NUM>. A second port <NUM> of the direct-cooling device of the battery pack <NUM> communicates with a refrigerant inlet of the heat exchanger <NUM> through a first throttle branch <NUM>, and a refrigerant outlet of the heat exchanger <NUM> communicates with an inlet of the compressor <NUM>.

In the present invention, the upstream and downstream sequence of the water pump <NUM>, the heat exchanger <NUM>, and the high-voltage system cooling branch <NUM> is not limited. For example, as shown in <FIG>, the high-voltage system cooling branch <NUM>, the heat exchanger <NUM>, and the water pump <NUM> are arranged in sequence in a flow direction of a cooling liquid. Alternatively, as shown in <FIG>, the heat exchanger <NUM>, the high-voltage system cooling branch <NUM>, and the water pump <NUM> are arranged in sequence in the flow direction of the cooling liquid, or the water pump <NUM>, the heat exchanger <NUM>, and the high-voltage system cooling branch <NUM> are arranged in sequence in the flow direction of the cooling liquid, or the cooling branch <NUM>, the water pump <NUM>, and the heat exchanger <NUM> are arranged in sequence in the flow direction of the cooling liquid, and so on. In the present invention, for the convenience of explanation and description, the arrangement mode shown in <FIG> is used as an example for description.

In the above technical solutions, a high-voltage system includes devices operating at high voltages such as a motor, a motor controller, and a three-in-one charging and distribution unit. Since the devices operate at a high voltage, a lot of heat may be generated during the operation. The heat exchanger <NUM> is provided with four inlet and outlet port in total, which are respectively a refrigerant inlet and a refrigerant outlet for circulation of a refrigerant, and a cooling liquid inlet and a cooling liquid outlet for circulation of the cooling liquid.

The "heat sink <NUM>" in the present invention functions as a heat exchanger and can exchange heat with the external environment. When the vehicle thermal management system <NUM> needs heating, the heat sink <NUM> can absorb heat from the external environment, and when the vehicle thermal management system <NUM> needs cooling, the heat sink <NUM> can dissipate heat to the external environment.

In order to prevent damage to the compressor <NUM>, the vehicle thermal management system <NUM> in the present invention further includes a gas-liquid separator. An outlet of the gas-liquid separator communicates with the inlet of the compressor <NUM>, and all branches that need to communicate with the inlet of the compressor <NUM> need to pass through the gas-liquid separator and then enter the compressor <NUM>. In this way, the refrigerant may first be subjected to gas-liquid separation through the gas-liquid separator, and the separated gas flows back to the compressor <NUM>, thereby preventing the liquid refrigerant from entering the compressor <NUM> and damaging the compressor <NUM>, so as to extend the service life of the compressor <NUM> and improve the efficiency of the whole heat pump air conditioning system.

In the above second thermal management system <NUM>, the reversing valve <NUM> may be used for switching to change a flow path of the cooling liquid to cause the cooling liquid to flow through the heat sink <NUM> or not, so that the second thermal management system <NUM> includes two operating modes: a high-voltage system waste heat utilization mode and a high-voltage system waste heat plus external environment energy mode. In the external environment energy mode, when it is necessary to absorb heat from the external environment, the operating mode is a mode of absorbing external environment energy. When it is necessary to release heat to the external environment, the operating mode is a mode of releasing energy to the external environment.

When the second thermal management system <NUM> is in the high-voltage system waste heat utilization mode, the cooling liquid flow path is as follows: referring to <FIG>, water pump <NUM>-reversing valve <NUM> (ports a and b communicating with each other)-high-voltage system cooling branch <NUM>-cooling liquid inlet of the heat exchanger <NUM>-cooling liquid outlet of the heat exchanger <NUM>-water pump <NUM>. In this operating mode, the cooling liquid may absorb heat of devices in the high-voltage system when flowing through the high-voltage system, and then return to the heat exchanger <NUM> to exchange heat with the refrigerant flowing through the heat exchanger <NUM>, so as to raise the temperature of the refrigerant.

When the second thermal management system <NUM> is in the high-voltage system waste heat plus external environment energy mode (the mode of absorbing external environment energy and releasing energy to the external environment), the cooling liquid flow path is as follows: referring to <FIG>, water pump <NUM>-reversing valve <NUM> (ports a and c communicating with each other)-heat sink <NUM>-high-voltage system cooling branch <NUM>-cooling liquid inlet of the heat exchanger <NUM>-cooling liquid outlet of the heat exchanger <NUM>-water pump <NUM>.

In the mode of absorbing external environment energy, the cooling liquid flowing out from the water pump <NUM> absorbs heat in the environment when flowing through the heat sink <NUM>, then continues to absorb heat of devices in the high-voltage system when flowing through the high-voltage system, and then returns to the heat exchanger <NUM> to exchange heat with the refrigerant flowing through the heat exchanger <NUM>, so as to raise the temperature of the refrigerant. By adding a heat source in the second thermal management system <NUM>, the heat absorbed from the external environment and the heat absorbed from the high-voltage system are superimposed, and more heat is absorbed, to cause the refrigerant to absorb more heat from the cooling liquid, thereby increasing the energy utilization of the vehicle.

In the mode of releasing heat to the external environment, the cooling liquid flowing out from the water pump <NUM> releases heat to the external environment when flowing through the heat sink <NUM>, then continues to exchange heat with the high-voltage system when flowing through the high-voltage system, and then returns to the heat exchanger <NUM> to exchange heat with the refrigerant flowing through the heat exchanger <NUM>, so as to lower the temperature of the refrigerant.

In an implementation, the mode of the second thermal management system <NUM> is selected according to a specific heating requirement of the battery pack <NUM>. When waste heat of the high-voltage system is enough to heat the battery pack <NUM> to a specified temperature, the second thermal management system <NUM> is in the high-voltage system waste heat utilization mode. When the waste heat of the high-voltage system is not enough to heat the battery pack <NUM> to a specified temperature, the second thermal management system <NUM> is in a high-voltage system waste heat plus external environment energy mode. It may be understood that in other implementations, the mode of the second thermal management system <NUM> may also be set according to other requirements.

Through the above technical solutions, when the ambient temperature is relatively low and it is necessary to heat the battery pack <NUM>, refer to <FIG> and <FIG>, the first thermal management system <NUM> is in a heating mode of the battery pack <NUM>, and the second thermal management system <NUM> is in the high-voltage system waste heat utilization mode or the high-voltage system waste heat plus external environment energy mode in this case. In the heating mode of the battery pack <NUM>, a circulation circuit of the refrigerant is as follows: compressor <NUM>-first port <NUM> of direct-cooling device of battery pack <NUM>-second port <NUM> of direct-cooling device of battery pack <NUM>-first throttle branch <NUM>-heat exchanger <NUM>-gas-liquid separator-compressor <NUM>. The specific process is that the electric compressor <NUM> starts to operate to compress the refrigerant, a high-temperature and high-pressure gaseous refrigerant flows out from the compressor <NUM>, and the high-temperature and high-pressure gaseous refrigerant flows into the direct-cooling device inside the battery pack <NUM> and releases a lot of heat for heat exchange with the battery pack <NUM>. A medium-temperature and high-pressure refrigerant after heat exchange becomes a low-temperature and low-pressure liquid after being throttled and depressurized by the first throttle branch <NUM>, and then enters the heat exchanger <NUM> to absorb heat. The high-temperature and low-pressure refrigerant after heat absorption returns to the compressor <NUM> through the gas-liquid separator to enter a next cycle.

The high-voltage system cooling branch <NUM> may exchange heat with the high-voltage system and absorb the heat in the high-voltage system when flowing through the high-voltage system. When flowing through the heat exchanger <NUM>, the cooling liquid with absorbed heat from the high-voltage system may exchange heat with the refrigerant flowing through the heat exchanger <NUM>, thereby transferring the heat absorbed from the high-voltage system to the refrigerant. In this way, the recycled heat may be used to heat the battery pack <NUM>, and the waste heat of the high-voltage system can be effectively used. Therefore, the battery pack <NUM> may be further heated by using the heat while cooling the devices in the high-voltage system, which improves the energy utilization. It is not necessary to heat the battery pack <NUM> with an air conditioner. Therefore, the heating energy efficiency of the air conditioner system for the passenger compartment can be improved.

In addition, since the direct-cooling device is arranged on the battery pack <NUM>, the heat exchange between the refrigerant and the battery pack <NUM> is completed through the direct-cooling device. Therefore, it is unnecessary to arrange, on the battery pack <NUM>, an additional heat exchanger and a pipeline communicating with the additional heat exchanger for cooling the battery pack <NUM>, which simplifies the pipeline arrangement for heating and cooling the battery pack <NUM> and reduces the cost. The refrigerant is directly used to exchange heat with the battery pack <NUM>, which has high heat exchange efficiency and is not affected by the external environment. No matter in a high-temperature or low-temperature environment, the battery pack <NUM> can operate within a suitable temperature range, which improves the charging and discharging efficiency of the battery pack <NUM>, improves the endurance, extends the service life of the battery pack <NUM>, and ensures the safety of the battery pack <NUM>.

In order to improve the heating and cooling efficiency of the battery pack <NUM>, in an implementation of the present invention, the battery pack <NUM> includes a battery module and the direct-cooling device. The direct-cooling device includes multiple cooling pipelines configured to guide a refrigerant. The multiple cooling pipelines are laid on a surface of the battery module. The direct-cooling device is constructed to transfer heat from the battery module to the refrigerant when cooling the battery, or transfer heat from the refrigerant to the battery module when heating the battery. The direct-cooling device is not limited to only cooling the battery pack <NUM>. When a temperature of the refrigerant in the direct-cooling device is higher than a temperature of the battery pack <NUM>, the direct-cooling device heats the battery pack <NUM> at this time. When a temperature of the refrigerant in the direct-cooling device is lower than the temperature of the battery pack <NUM>, the direct-cooling device cools the battery pack <NUM> at this time.

It should be noted herein that in the present invention, the battery pack <NUM> may include a battery pack box and multiple battery modules arranged in the battery pack box, and the direct-cooling device is arranged in the battery pack box and closely attached to the multiple battery modules. In this way, the refrigerant flows through the direct-cooling device, and the direct-cooling device is closely attached to the multiple battery modules, to cause the refrigerant to directly exchange heat with the battery modules, thereby improving the heat exchange efficiency.

Optionally, in an implementation of the present invention, the heat exchanger <NUM> is a plate heat exchanger <NUM>, and the plate heat exchanger <NUM> is a high efficiency heat exchanger <NUM> formed by stacking a series of metal sheets having a certain corrugated shape. Thin rectangular channels are formed among various plates, and heat exchange is performed through the plates. The plate heat exchanger <NUM> has the characteristics such as high heat exchange efficiency, small heat loss, a compact and light structure, a small floor space, wide application, long service life, and the like. Under the same pressure loss, the heat transfer coefficient of the plate heat exchanger is <NUM>-<NUM> times higher than that of a tubular heat exchanger <NUM>, the occupied area is one third of the tubular heat exchanger <NUM>, and the heat recovery rate may be as high as over <NUM>%. Therefore, the plate heat exchanger does not occupy excessively large space on the vehicle.

In order to cool the battery pack <NUM> when the temperature of the battery pack <NUM> is excessively high, in an implementation of the present invention, as shown in <FIG>, the first thermal management system further includes a bi-directional expansion assembly <NUM>. The outlet of the compressor <NUM> optionally communicates with the refrigerant inlet of the heat exchanger <NUM> through the first branch <NUM>, and/or with the first port <NUM> of the direct-cooling device of the battery pack <NUM> through a first flow branch <NUM>. That is to say, the outlet of the compressor <NUM> optionally communicates with at least one of the refrigerant inlet of the heat exchanger <NUM> and the first port <NUM> of the direct-cooling device of the battery pack <NUM>. The second port <NUM> of the direct-cooling device of the battery pack <NUM> is in unidirectional communication with a refrigerant inlet of the heat exchanger <NUM> through the bi-directional expansion assembly <NUM>, and a refrigerant outlet of the heat exchanger <NUM> communicates with an inlet of the compressor <NUM> through a second flow branch <NUM>. The first port <NUM> of the direct-cooling device of the battery pack <NUM> further communicates with the inlet of the compressor <NUM> through a third flow branch <NUM>. The second port <NUM> of the direct-cooling device of the battery pack <NUM> is in unidirectional communication with the refrigerant inlet of the heat exchanger <NUM>, which can prevent the refrigerant flowing out from the outlet of the compressor <NUM> from directly flowing to the battery pack <NUM> when cooling the battery pack <NUM>.

Optionally, in an implementation of the present invention, a third switch valve <NUM> is arranged on the third flow branch <NUM>, and the third switch valve <NUM> is constructed to be open only when the flow direction of the refrigerant in the battery pack <NUM> is from the second port <NUM> to the first port <NUM> of the direct-cooling device of the battery pack <NUM>.

Through the above technical solutions, when the temperature of the battery pack <NUM> is excessively high and it is necessary to cool the battery pack <NUM>, refer to <FIG>. In this case, the first thermal management system <NUM> is in a battery pack <NUM> cooling mode, and the second thermal management system <NUM> is in the mode of high-voltage system waste heat plus releasing energy to the external environment. In this case, the heat sink <NUM> functions to release a large amount of heat to the external environment. The circulation circuit of the refrigerant is as follows: compressor <NUM>-first branch <NUM>-heat exchanger <NUM>-bi-directional expansion assembly <NUM>-second port <NUM> of direct-cooling device of battery pack <NUM>-first port <NUM> of direct-cooling device of battery pack <NUM>-gas-liquid separator-compressor <NUM>. When the temperature of the battery pack <NUM> is relatively high, the electric compressor <NUM> starts to operate. The high-temperature and high-pressure gaseous refrigerant from the compressor <NUM> flows into the heat exchanger <NUM> to exchange heat with the cooling liquid in the heat exchanger <NUM>, and releases a lot of heat. The low-temperature refrigerant after heat exchange enters the battery pack <NUM> after throttling and depressurization through the bi-directional expansion assembly <NUM> and absorbs the heat of the battery pack <NUM>, and the high-temperature refrigerant after heat absorption returns to the compressor <NUM> through the gas-liquid separator to enter the next cycle. The bi-directional expansion assembly in the circuit functions to control the flow direction of the refrigerant, especially prevent the refrigerant flowing out from the second port <NUM> of the battery pack <NUM> from directly returning to the compressor <NUM> in the heating mode of the battery pack <NUM>.

In addition, by properly arranging the bi-directional expansion assembly <NUM>, the same branch can be used for heating and cooling of the battery pack <NUM>. Only the flow direction of the refrigerant in the pipeline is changed, and no additional pipeline is required, which further simplifies the pipeline arrangement.

Optionally, in an implementation, the third switch valve <NUM> and the following switch valves such as the first switch valve <NUM> and the second switch valve <NUM> may be solenoid valves. It may be understood that in other implementations, the switch valves such as the first switch valve <NUM>, the second switch valve <NUM>, and the third switch valve <NUM> may be any valve that can realize the switch function, which is not limited in the present invention. For example, the switch valve may be the reversing valve <NUM>, or the like. Other switch valves (such as the first switch valve <NUM> and the second switch valve <NUM>) appearing in the following of the present invention may be solenoid valves or other valves that can realize the switch function, which is not limited in the present invention, and the details are not described below.

In the present invention, the refrigerant flowing out from the compressor <NUM> optionally flows through the battery pack <NUM> or the first branch <NUM>. In order to control the flow direction of the refrigerant, in an implementation of the present invention, as shown in <FIG>, an expansion switch valve <NUM> is provided on the first branch <NUM>, and the first switch valve <NUM> is provided on the first flow branch <NUM>.

Through the joint control of the expansion switch valve <NUM> and the first switch valve <NUM>, the flow direction of the refrigerant flowing out from the compressor <NUM> can be specifically controlled as follows. When the first switch valve <NUM> is opened and the expansion switch valve <NUM> is closed, the refrigerant from the compressor <NUM> only flows to the battery pack <NUM> and can only heat the battery pack <NUM>. When the first switch valve <NUM> is closed and the expansion switch valve <NUM> is opened, the refrigerant from the compressor <NUM> only flows to the first branch <NUM> (provided with the in-vehicle condenser <NUM>) and can only heat the passenger compartment. When the first switch valve <NUM> is opened and the expansion switch valve <NUM> is opened, the refrigerant from the compressor <NUM> flows to the battery pack <NUM> and the in-vehicle condenser <NUM> respectively, thereby simultaneously heating the passenger compartment and the battery pack <NUM>. Therefore, through the joint control of the expansion switch valve <NUM> and the first switch valve <NUM>, the outlet of the compressor <NUM> can optionally communicates with the first port <NUM> of the direct-cooling device of the battery pack <NUM> and/or in communication with the first branch <NUM>.

In the present invention, the specific structure of the bi-directional expansion assembly <NUM> is not limited, and may be arranged as required. In an implementation, as shown in <FIG>, the bi-directional expansion assembly <NUM> includes a bi-directional expansion valve <NUM>, a first check valve <NUM>, and a second check valve <NUM>. The bi-directional expansion valve <NUM> communicates with the second port <NUM> of the direct-cooling device, and the first check valve <NUM> communicates with the bi-directional expansion valve <NUM> to form a first one-way throttle branch for flowing from the second port <NUM> of the direct-cooling device to the refrigerant inlet of the heat exchanger <NUM>. The second check valve <NUM> communicates with the bi-directional expansion valve <NUM> to form a second one-way throttle branch for flowing from the refrigerant outlet of the heat exchanger <NUM> to the second port <NUM> of the direct-cooling device. The first one-way throttle branch includes the first throttle branch <NUM> and a first one-way branch <NUM>, and the second one-way throttle branch includes a second one-way branch <NUM> and the first throttle branch <NUM>.

Through the bi-directional expansion assembly <NUM>, when the battery pack <NUM> is heated, the refrigerant flows from the second port <NUM> of the direct-cooling device of the battery pack <NUM> to the refrigerant inlet of the heat exchanger <NUM> along a first channel, and when the battery pack <NUM> is cooled, the refrigerant flows from the refrigerant outlet of the heat exchanger <NUM> to the second port <NUM> of the direct-cooling device of the battery pack <NUM> along a second channel. Therefore, through the reasonable arrangement of the bi-directional expansion assembly <NUM>, the same branch can be used for heating and cooling of the battery pack <NUM>, so that no additional pipeline is necessary and the pipeline arrangement is simplified.

In the embodiment shown in <FIG>, the first check valve <NUM> forms the first one-way branch <NUM>, the second check valve forms the second one-way branch <NUM>, and the pipeline where the bi-directional expansion valve <NUM> is located forms the first throttle branch <NUM>. The second one-way branch <NUM> only allows the refrigerant flowing from the refrigerant outlet of the heat exchanger <NUM> to flow into the second port <NUM> of the direct-cooling device of the battery pack <NUM>, and the first one-way branch <NUM> only allows the refrigerant flowing from the second port <NUM> of the direct-cooling device of the battery pack <NUM> to flow into the refrigerant inlet of the heat exchanger <NUM>. The one-way communication manner can be realized in multiple manners. In an implementation of the present invention, the unidirectional communication manner is realized through a check valve. In other alternative implementations, a controllable switch valve may be arranged on the one-way branch, and the switch valve is open only when the flow direction of the refrigerant is correct. The third one-way branch <NUM> in the following may also be realized in at least two above manners, that is, by arranging a check valve or arranging a controllable switch valve.

As another implementation of the bi-directional expansion assembly <NUM>, as shown in <FIG>, the bi-directional expansion assembly <NUM> includes a fourth check valve <NUM>, a fifth check valve <NUM>, a sixth check valve <NUM>, a seventh check valve <NUM>, and a one-way expansion valve <NUM>. The fourth check valve <NUM> communicates with the sixth check valve <NUM> to form a first channel for flowing from the second port <NUM> of the direct-cooling device to the refrigerant inlet of the heat exchanger <NUM>. The fifth check valve <NUM> communicates with the seventh check valve <NUM> to form a second channel for flowing from the refrigerant outlet of the heat exchanger <NUM> to the second port <NUM> of the direct-cooling device. An outlet of the fourth check valve <NUM> and an outlet of the fifth check valve <NUM> both communicate with an inlet of the one-way expansion valve <NUM>, and an inlet of the sixth check valve <NUM> and an inlet of the seventh check valve <NUM> both communicate with an outlet of the one-way expansion valve <NUM>. In this way, the first channel forms the first one-way throttle branch, and the second channel forms the second one-way throttle branch. The first one-way throttle branch includes the fourth check valve <NUM>, the one-way expansion valve <NUM>, and the sixth check valve <NUM> which are opened in sequence, and the second one-way throttle branch includes the fifth check valve <NUM>, the one-way expansion valve <NUM>, and the seventh check valve <NUM> which are opened in sequence.

In order to heat the passenger compartment of the vehicle, in an implementation of the present invention, as shown in <FIG>, the first thermal management system <NUM> further includes an in-vehicle condenser <NUM>. The in-vehicle condenser <NUM> is arranged on the first branch <NUM>. An inlet of the in-vehicle condenser <NUM> communicates with the outlet of the compressor <NUM>. A second throttle branch <NUM> is arranged between an outlet of the in-vehicle condenser <NUM> and the refrigerant inlet of the heat exchanger <NUM>.

By arranging the in-vehicle condenser <NUM>, the vehicle thermal management system <NUM> can also realize the heating mode of the passenger compartment. In this case, as shown in <FIG> and <FIG>, the circulation circuit of the refrigerant is as follows: compressor <NUM>-in-vehicle condenser <NUM>-heat exchanger <NUM>-gas-liquid separator-compressor <NUM>.

The vehicle thermal management system <NUM> can also realize the mode of heating the passenger compartment and heating of the battery pack <NUM>. In this case, as shown in <FIG> and <FIG>, the circulation circuit of the refrigerant is as follows: compressor <NUM>-in-vehicle condenser <NUM>, battery pack <NUM>-heat exchanger <NUM>-gas-liquid separator-compressor <NUM>.

During the heating of the passenger compartment, in an implementation, the mode of the second thermal management system <NUM> is selected according to a specific heating requirement of the passenger compartment and/or the battery pack <NUM>. When waste heat of the high-voltage system is enough to heat the passenger compartment and/or the battery pack <NUM> to a specified temperature, the second thermal management system <NUM> is in the high-voltage system waste heat utilization mode. When the waste heat of the high-voltage system is not enough to heat the passenger compartment and/or the battery pack <NUM> to a specified temperature, the second thermal management system <NUM> is in a high-voltage system waste heat plus external environment energy mode. It may be understood that in other implementations, the mode of the second thermal management system <NUM> may also be set according to other requirements.

When the passenger compartment does not need to be heated, for example, in the heating and cooling mode of the battery pack <NUM> described above or the passenger compartment cooling mode described below, in this case, the air is controlled by the damper mechanism not to pass through the in-vehicle condenser <NUM>. Since no wind passes, heat exchange is not performed in the in-vehicle condenser <NUM>, and the in-vehicle condenser <NUM> is only used as a flow channel.

In an implementation of the present invention, as shown in <FIG>, the first thermal management system <NUM> further includes an expansion switch valve <NUM>. The expansion switch valve <NUM> is provided with a flow channel and a throttle flow channel therein. When the expansion switch valve <NUM> is used as a switch valve, the flow channel inside the expansion switch valve is unobstructed. When the expansion switch valve <NUM> is used as an expansion valve, the throttle flow channel inside the expansion switch valve is unobstructed.

The expansion switch valve <NUM> is arranged on the first branch <NUM>. An inlet of the expansion switch valve <NUM> communicates with the outlet of the in-vehicle condenser <NUM>, and an outlet of the expansion switch valve <NUM> communicates with the refrigerant inlet of the heat exchanger <NUM>.

In the present invention, the expansion switch valve <NUM> is a valve with the functions of both the expansion valve and the switch valve, which may be regarded as the integration of the switch valve and the expansion valve. An example implementation of the expansion switch valve <NUM> is to be provided below.

When the passenger compartment is heated by the heat exchanger <NUM>, the expansion switch valve <NUM> is used as the expansion valve, and the high-temperature and high-pressure refrigerant flowing out from the compressor <NUM> is throttled and depressurized through the throttle flow channel inside the expansion switch valve <NUM> and then provided to the heat exchanger <NUM>. In the cooling mode of the battery pack <NUM>, the expansion switch valve <NUM> is used as the switch valve, and the refrigerant flowing out from the compressor <NUM> is provided to the heat exchanger <NUM> through the flow channel inside the expansion switch valve <NUM> and then flows to the battery pack <NUM>. When the refrigerant flowing out from the compressor <NUM> needs to flow through the first branch <NUM>, the expansion switch valve <NUM> is opened. When the refrigerant flowing out from the compressor <NUM> only flows directly to the battery pack <NUM> (for example, when only the battery pack <NUM> is heated), the expansion switch valve <NUM> is closed, thereby closing the first branch <NUM>, so that the refrigerant flowing out from the compressor <NUM> all flows into the branch where the battery pack <NUM> is located.

As shown in <FIG>, the expansion switch valve <NUM> mentioned above may include a valve body <NUM>. An inlet, an outlet, and an internal flow channel communicating the inlet with the outlet are formed on the valve body, and a first valve core <NUM> and a second valve core <NUM> are mounted on the internal flow channel. The first valve core <NUM> directly communicates the inlet <NUM> with the outlet <NUM> or cuts off the communication, and the second valve core <NUM> communicates the inlet <NUM> with the outlet <NUM> or cuts off the communication through a throttle port <NUM>.

The "direct communication" realized by the first valve core <NUM> means that the coolant entering from the inlet <NUM> of the valve body <NUM> may pass over the first valve core <NUM> and flow directly to the outlet <NUM> of the valve body <NUM> through the internal flow channel without being affected. The "cutting communication" realized by the first valve core <NUM> means that the coolant entering from the inlet <NUM> of the valve body <NUM> cannot pass over the first valve core <NUM> and cannot flow to the outlet <NUM> of the valve body <NUM> through the internal flow channel. The "communication through the throttle port" realized by the second valve core <NUM> means that the coolant entering from the inlet <NUM> of the valve body <NUM> may pass over the second valve core <NUM> and flow to the outlet <NUM> of the valve body <NUM> through throttling of the throttle port <NUM>. The "cutting communication" realized by the second valve core <NUM> means that the coolant entering from the inlet <NUM> of the valve body <NUM> cannot pass over the second valve core <NUM> and cannot flow to the outlet <NUM> of the valve body <NUM> through the throttle port <NUM>.

In this way, by controlling the first valve core <NUM> and the second valve core <NUM>, the expansion switch valve <NUM> of the present invention can cause the coolant entering from the inlet <NUM> to realize at least three states, that is, <NUM>) a cut-off state; <NUM>) a direct communication state of the first valve core <NUM> that is passed over; and <NUM>) a throttle communication manner of the second valve core <NUM> that is passed over.

The high-temperature and high-pressure liquid refrigerant may become a low-temperature and low-pressure vaporous hydraulic refrigerant after being throttled by the throttle <NUM>, which can create conditions for the evaporation of the refrigerant. That is to say, a cross-sectional area of the throttle port <NUM> is less than a cross-sectional area of the outlet <NUM>, and an opening degree of the throttle <NUM> can be adjusted by controlling the second valve core <NUM> to control the flow through the throttle port <NUM>, thereby preventing insufficient refrigeration caused by excessively few refrigerants, and preventing the compressor from liquid hammer caused by excessively many refrigerants. That is to say, the mating between the second valve core <NUM> and the valve body <NUM> may cause the expansion switch valve <NUM> to have the function of the expansion valve.

In this way, the first valve core <NUM> and the second valve core <NUM> are mounted on the internal flow channel of the same valve body <NUM>, to realize the open/closing control and/or throttling control function of the inlet <NUM> and the outlet <NUM>, and the structure is simple and easy to produce and mount. In addition, when the expansion switch valve <NUM> provided in the present invention is applied to the thermal management system, since the expansion switch valve <NUM> is the integration of the switch valve and the expansion valve, compared with the arrangement of at least two parallel branches (a flow branch and a throttle branch) in the related art, only one branch flowing through the expansion switch valve <NUM> needs to be arranged. In this way, the pipeline connection is simplified, which is more conducive to oil return of the thermal management system, which can reduce the refrigerant charge of the whole thermal management system and reduce the cost.

As an exemplary internal mounting structure of the valve body <NUM>, as shown in <FIG>, the valve body <NUM> includes a valve seat forming an internal flow channel, and a first valve housing <NUM> and a second valve housing <NUM> mounted on the valve seat. A first electromagnetic driving portion <NUM> configured to drive the first valve core <NUM> is mounted in the first valve housing <NUM>, and a second electromagnetic driving portion <NUM> configured to drive the second valve core <NUM> is mounted in the second valve housing <NUM>. The first valve core <NUM> extends from the first valve housing <NUM> to the internal flow channel in the valve seat <NUM>, and the second valve core <NUM> extends from the second valve housing <NUM> to the internal flow channel in the valve seat <NUM>.

A position of the first valve core <NUM> can be conveniently controlled by controlling the on-off of the first electromagnetic driving portion <NUM> (such as an electromagnetic coil), so as to control the inlet <NUM> and the outlet <NUM> to be directly communicated or the communication between the inlet and the outlet to be cut off. A position of the second valve core <NUM> can be conveniently controlled by controlling the on-off of the second electromagnetic driving portion <NUM> (such as an electromagnetic coil), so as to control the inlet <NUM> and the outlet <NUM> to be communicated with the throttle port <NUM> or not. In other words, an electronic expansion valve and a solenoid valve sharing the inlet <NUM> and the outlet <NUM> are mounted in the valve body <NUM> in parallel. Therefore, the automatic control of closing/opening and/or throttling of the expansion switch valve can be realized, and the pipeline direction can be simplified.

As an alternative implementation of the expansion switch valve <NUM>, an expansion valve may be arranged on the first branch <NUM>, and a switch valve may be arranged in parallel with the expansion valve. When the refrigerant does not need to be throttled, the expansion valve is closed and the switch valve is opened, to cause the refrigerant to directly flow through the branch where the switch valve is located. When the refrigerant needs to be throttled, the expansion valve is opened and the switch valve is closed, to cause the refrigerant to flow through the first branch <NUM> where the expansion valve is located.

In order to realize the refrigeration of the passenger compartment of the vehicle, in an implementation of the present invention, as shown in <FIG>, the first thermal management system <NUM> further includes an in-vehicle evaporator <NUM>. The refrigerant outlet of the heat exchanger <NUM> communicates with an inlet of the in-vehicle evaporator <NUM> through a third throttle branch <NUM>, and an outlet of the in-vehicle evaporator <NUM> communicates with the inlet of the compressor <NUM> through a third one-way branch <NUM>. A third check valve <NUM> is arranged on the third one-way branch <NUM>. The third check valve <NUM> only allows the refrigerant flowing out from the outlet of the in-vehicle evaporator <NUM> to return to the compressor <NUM>.

The vehicle thermal management system <NUM> may further realize various passenger compartment cooling modes by arranging the in-vehicle evaporator <NUM>. In this case, as shown in <FIG>, the second thermal management system <NUM> is in the mode of high-voltage system waste heat plus releasing energy to the external environment. In this case, the heat sink <NUM> functions to release a large amount of heat to the external environment.

In this case, the air is controlled by the damper mechanism not to pass through the in-vehicle condenser <NUM>, and the in-vehicle condenser <NUM> is only used as a flow channel. The high-temperature and high-pressure refrigerant flowing out from the outlet of the in-vehicle condenser <NUM> enters the heat exchanger <NUM> for heat exchange through the flow branch of the expansion switch valve <NUM>. The low-temperature and high-pressure refrigerant is throttled and depressurized by the electronic expansion valve <NUM> on the third throttle branch <NUM> to become the low-temperature and low-pressure refrigerant, and enters the in-vehicle evaporator <NUM> to evaporate and absorb heat, thereby reducing the temperature of the passenger compartment of the vehicle. In the passenger compartment cooling mode, the first switch valve <NUM> is closed and the second switch valve <NUM> is closed. The circulation circuit of the refrigerant is as follows: compressor <NUM>-in-vehicle condenser <NUM> (without heat exchange)-flow channel of expansion switch valve <NUM>-heat exchanger <NUM>-third throttle branch <NUM> (electronic expansion valve <NUM>)-in-vehicle evaporator <NUM>-third one-way branch <NUM>-gas-liquid separator-compressor <NUM>.

In the present invention, the refrigerant flowing out from the heat exchanger <NUM> can alternatively flow through the battery pack <NUM> or back to the compressor <NUM> or the in-vehicle evaporator <NUM>. In order to control the flow direction of the refrigerant, in an implementation of the present invention, as shown in <FIG>, the second switch valve <NUM> is arranged on the second flow branch <NUM>, and the electronic expansion valve <NUM> is arranged on the third throttle branch <NUM>.

By arranging the bi-directional expansion assembly, the electronic expansion valve <NUM> on the third throttle branch <NUM>, and the second switch valve <NUM> on the second flow branch <NUM>, the specific flow direction of the refrigerant flowing out from the outlet of the heat exchanger <NUM> can be controlled through the joint control of the bi-directional expansion valve <NUM>, the electronic expansion valve <NUM>, and the second switch valve <NUM>, so that the refrigerant flowing out from the outlet of the heat exchanger <NUM> can alternatively flow to at least one of the battery pack <NUM>, the in-vehicle evaporator <NUM>, or the compressor <NUM>.

In order to further improve the heating capacity of the passenger compartment, as shown in <FIG>, the first thermal management system <NUM> further includes a heater <NUM>. The heater <NUM> is configured to heat air passing through the in-vehicle condenser <NUM> to supply heat to a vehicle. The heater <NUM> may be an air heater <NUM> (APTC). When the heat released when the flowing refrigerant is condensed by the in-vehicle condenser <NUM> is not enough to heat the air to the required temperature, the heater <NUM> may be turned on, the air is further heated by the heater <NUM>, so as to meet the heating requirements of the passenger compartment.

In order to accelerate the heat dissipation of the heat sink <NUM> and improve the heat dissipation effect, in an implementation of the present invention, as shown in <FIG>, the second thermal management system <NUM> further includes a fan <NUM>. The fan <NUM> is disposed opposite to the heat sink <NUM> to accelerate the heat dissipation of the heat sink <NUM>. When the second thermal management system <NUM> is in the mode of high-voltage system waste heat plus external environment energy and needs to dissipate heat to the external environment, the fan <NUM> is turned on to accelerate the heat dissipation.

In order to improve the heating effect of the battery pack <NUM>, in an implementation of the present invention, as shown in <FIG>, the battery pack <NUM> includes a self-heating device (not shown) configured to increase heat generated by the battery module. The self-heating device includes a controller, a first motor electric control circuit <NUM>, and a second motor electric control circuit <NUM>. The first motor electric control circuit <NUM> and the second motor electric control circuit <NUM> are respectively electrically connected with the battery pack <NUM>, and the controller is respectively electrically connected with the first motor electric control circuit <NUM> and the second motor electric control circuit <NUM>. When the controller is configured to operate in a first control mode, the controller is configured to control the first motor electric control circuit <NUM> to charge and discharge the battery pack <NUM> to multiple times, so as to heat the battery pack <NUM>, and control the second motor electric control circuit <NUM> to output torque.

The self-heating device of this embodiment includes the first motor electric control circuit <NUM>, a second motor electric control circuit <NUM>, a first energy storage module, and a controller. When the controller is configured to operate in the first control mode, the controller controls a first motor inverter in the first motor electric control circuit <NUM> to cause the battery pack <NUM>, the first motor inverter, and a first motor winding to form a first battery pack heating circuit. An internal resistance of the battery pack <NUM> is heated by the first battery pack heating circuit, and a second motor inverter in the second motor electric control circuit <NUM> is controlled to cause the second motor electric control circuit <NUM> to output power, thereby realizing the coordination of the heating of the battery pack <NUM> and the driving of the motor. In addition, since the first motor electric control circuit <NUM> is used for heating and the second motor electric control circuit <NUM> is used for driving, an excessive loss of the motor winding and the motor inverter in the motor driving circuit is avoided, and the service life of a device in a circuit is extended.

The first battery pack heating circuit is realized through a battery oscillation heating circuit module. The battery oscillation heating circuit can realize high-frequency alternating charging and discharging of the battery pack, and the circuit further includes multiple energy storage elements and switching elements. When the temperature of the battery pack reaches a heating start threshold, the battery pack is alternately charged and discharged with the energy storage elements, and the self-heating of the battery pack is realized by using the characteristics of high low-temperature resistance of the battery pack itself. The energy storage elements include a capacitor, an inductor, and the like. The alternating charging and discharging frequency between the battery pack and the energy storage elements is realized by the switching elements.

As another implementation of heating the battery pack <NUM>, the battery pack <NUM> may include an electric heating film (not shown) configured to increase the heat of the battery module, and the electric heating film is overlaid on the battery module for providing heat for the battery module. The electric heating film, for example, may be a translucent polyester film that can generate heat after being energized, and is made of conductive special ink and metal current-carrying strips machined and hot-pressed between insulating polyester films. During the operation, the electric heating film is used as a heating element, and transfers heat into the space by radiation, to cause the heated object to obtain heat, thereby raising the temperature. The electric heating film has a high conversion efficiency since it is a purely resistive circuit. Except a loss of a small fraction, a majority of the electric energy is converted into heat energy to heat the battery pack <NUM>.

By arranging the self-heating device on the battery pack <NUM> and superposing the heat exchange device having the refrigerant flowing therein with the self-heating device, the heating effect of the battery pack <NUM> can be significantly improved, and the battery heating rate is increased. In addition, since a lot of heat is generated in the high-voltage system when the battery pack <NUM> is heated by using the self-heating device, the energy utilization rate can be improved by using the waste heat of the high-voltage system.

The present invention further provides an electric vehicle, including the vehicle thermal management system <NUM> provided in any of the above. The electric vehicle may include a pure electric vehicle, a hybrid vehicle, a fuel cell vehicle, and the like.

Preferred implementations of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the foregoing implementations. Multiple simple variations may be made to the technical solutions of the present invention within the
scope of the present invention as defined by the appended claims.

Claim 1:
A vehicle thermal management system, comprising: a first thermal management system (<NUM>) and a second thermal management system (<NUM>) for a high-voltage system, wherein the second thermal management system (<NUM>) comprises a heat sink (<NUM>), a heat exchanger (<NUM>), and a waste heat utilization branch (<NUM>); a water pump (<NUM>) and a high-voltage system cooling branch (<NUM>) passing through the high-voltage system that are interconnected are arranged on the waste heat utilization branch (<NUM>); a cooling liquid outlet of the heat exchanger (<NUM>) communicates with an inlet of the waste heat utilization branch (<NUM>); an outlet of the waste heat utilization branch (<NUM>) optionally communicates directly with a cooling liquid inlet of the heat exchanger (<NUM>) or with the cooling liquid inlet of the heat exchanger (<NUM>) through the heat sink (<NUM>); characterized in that
the first thermal management system (<NUM>) comprises a compressor (<NUM>) and a battery pack (<NUM>) provided with a direct-cooling device; an outlet of the compressor (<NUM>) communicates with a first port (<NUM>) of the direct-cooling device of the battery pack (<NUM>); a second port (<NUM>) of the direct-cooling device of the battery pack (<NUM>) communicates with a refrigerant inlet of the heat exchanger (<NUM>) through a first throttle branch (<NUM>); and a refrigerant outlet of the heat exchanger (<NUM>) communicates with an inlet of the compressor (<NUM>).