Electrically powered motor vehicle and methods for its operation

Abstract

The invention relates to an electrically powered motor vehicle (2). This vehicle comprises a battery (4), in particular configured as a traction battery for a drive system, a battery cooling circuit (14) for the battery (4), with a first heat exchanger (20) and with a first cooling medium (18), and a heat exchanger assembly (22) with a second heat exchanger (24) and with a second cooling medium (28), wherein the first cooling medium (18) in the first heat exchanger (20) can be cooled by means of the heat exchanger assembly (22). The invention further relates to a method for operating such a motor vehicle (2).

Description

[0001] The invention relates to an electrically powered motor vehicle with a battery that can be cooled by a battery cooling circuit. Furthermore, the invention relates to a method for operating such a motor vehicle.

[0002] An electrically powered motor vehicle includes a battery, also known as a traction battery or high-voltage battery. This battery supplies electrical energy to an electric motor to drive the vehicle. For example, the battery is designed as a lithium-ion battery.

[0003] When a current flows through the battery, for example when the battery provides electrical energy for a drive or for another consumer, or when the battery is charged, it heats up.

[0004] To prevent damage or aging of the battery due to relatively high temperatures, the battery is typically cooled. For this purpose, cooling plates are installed in or on the battery, through which a cooling medium flows.

[0005] The term “electrically powered motor vehicles” includes motor vehicles that are purely electrically powered, i.e. that are only driven by an electric motor, as well as hybrid vehicles that have an additional motor, in particular an internal combustion engine, in addition to the electric motor drive.

[0006] The invention is based on the object of providing an electrically powered motor vehicle with suitable cooling for its battery. Furthermore, a method for operating such a motor vehicle is to be provided.

[0007] With regard to the electrically powered motor vehicle, the object is achieved according to the invention by the features of claim 1. With regard to the method, the object is achieved according to the invention by the features of claim 8. Advantageous embodiments and further developments are the subject of the dependent claims. The statements made in connection with the electrically powered motor vehicle also apply mutatis mutandis to the method, and vice versa.

[0008] The electrically powered motor vehicle, which will also be referred to below as a motor vehicle or vehicle for short, comprises a battery (traction battery) by means of which the motor vehicle can be powered. The battery therefore provides electrical energy for a (traction) drive, in particular for its electric motor, of the motor vehicle. Furthermore, the motor vehicle comprises a battery cooling circuit for the battery. The cooling circuit comprises a cooling device, in particular a cooling plate, for cooling the battery, suitably for cooling battery cells of the battery. For this purpose, the battery cooling circuit comprises a (first) cooling medium which flows through the cooling device to cool the battery. The first cooling medium therefore absorbs thermal energy from the battery during the cooling process.

[0009] The battery cooling circuit further comprises a heat exchanger, referred to below as the first heat exchanger, which is fluidically connected, preferably directly, to the cooling device. During operation, the first cooling medium (first coolant, first refrigerant) expediently flows from the heat exchanger to the cooling device and from there back. The first cooling medium is expediently pumped through the battery cooling circuit by a pump. The first heat exchanger serves to cool the cooling medium, in particular by transferring heat transferred from the battery to the cooling medium at the first heat exchanger to its surroundings. For example, the first heat exchanger is designed in the manner of a cooler (radiator).

[0010] The electrically powered motor vehicle further comprises a heat exchanger device, which comprises a second heat exchanger and a second cooling medium (second coolant, second refrigerant) for the second heat exchanger. According to the invention, the first coolant of the battery cooling circuit can be cooled in the first heat exchanger using the heat exchanger device. In other words, the heat exchanger device is provided and configured to extract heat from the first heat exchanger of the battery cooling circuit, thereby cooling the first cooling medium flowing through it.

[0011] In this case, the battery cooling circuit and a cooling medium circuit for the second coolant of the heat exchanger device are expediently designed separately from each other. In other words, the first cooling medium flows only in the battery cooling circuit, and the second cooling medium flows only in the cooling medium circuit for the heat exchanger device.

[0012] In summary, the first cooling medium is cooled by the heat exchanger device. Advantageously, such cooling reduces or even prevents heating, particularly comparatively strong heating of the battery, for example during a charging process, especially during a rapid charging process. This prevents battery aging and / or damage due to a comparatively high temperature, or at least reduces the risk of such damage. Furthermore, by cooling the first heat exchanger or the first cooling medium by means of the heat exchanger device, a comparable strong and / or efficient cooling is achieved.

[0013] According to an advantageous development, the first heat exchanger is or can be thermally coupled to the second heat exchanger. Cooling of the first cooling medium is thus achieved by means of the second heat exchanger. For example, the second heat exchanger cools its surroundings, in particular its ambient air, and the first heat exchanger is in turn cooled by the cooled ambient air. Alternatively or additionally, the first heat exchanger is in mechanical contact with the second heat exchanger, so that heat conduction can also occur between them. For example, the first heat exchanger rests against the second heat exchanger.

[0014] In a suitable embodiment of the motor vehicle, the heat exchanger device comprises a fan which is provided and configured to generate an air flow on and / or over the first heat exchanger and / or on and / or over the second heat exchanger.

[0015] For example, the fan is configured to direct the air cooled by the second heat exchanger to the first heat exchanger, in particular by sucking or blowing it. For this purpose, the first and second heat exchangers are expediently arranged one behind the other in the direction of air flow. In particular, the first and second heat exchangers are thermally coupled to one another by means of the air flow generated by the fan.

[0016] Alternatively or additionally, the fan is configured to direct ambient air over or to the first heat exchanger to cool it. Thermal coupling of the first and second heat exchangers is neither necessary nor practical in this variant.

[0017] In a separate configuration of the battery cooling circuit and the cooling medium circuit for the heat exchanger device, the first cooling medium is selected according to a cooling requirement for the battery, and the second cooling medium is selected according to an intended purpose, an intended cooling requirement, and / or the structure of the heat exchanger device. In summary, the first and second cooling medium are preferably adapted to the respective cooling medium circuit. For example, the same substance or the same mixture of substances is used for the first and second cooling medium. However, for particularly efficient adaptation to the respective cooling medium circuit, according to an advantageous configuration, the first cooling medium and the second cooling medium are different cooling media, i.e., different substances or mixtures of substances.

[0018] For example, the first and / or second cooling medium is either gaseous or liquid. For example, CO2, oil, or a water-glycol mixture is used as the first and / or second cooling medium.

[0019] According to a (first) embodiment, the motor vehicle suitably comprises an air conditioning system, which is particularly provided and configured to air-condition a passenger compartment. The second heat exchanger is the heat exchanger of the air conditioning system. The second heat exchanger is expediently an evaporator of the air conditioning system, which cools the air to be fed into the passenger compartment. The evaporator of the air conditioning system is thus used to cool this air. The evaporator is preferably thermally coupled to the first heat exchanger, in particular by means of the fan, wherein the air cooled by the evaporator is used to cool the first cooling medium.

[0020] Alternatively, a condenser of the air conditioning system is used to cool the first cooling medium. The condenser is preferably thermally coupled to the first heat exchanger, particularly via the fan. In this variant, the air conditioning system can be operated like a heat pump, so that air can also be cooled at the condenser. In other words, such an air conditioning system is configured to allow the second cooling medium to flow in both possible flow directions in the cooling medium circuit (refrigerant circuit) of the air conditioning system.

[0021] In summary, the first heat exchanger can be cooled by the second heat exchanger. Advantageously, in this embodiment, a heat exchanger of the air conditioning system already present in the motor vehicle is also used to cool the first cooling medium. However, the cooling capacity of the air conditioning system for the passenger compartment is correspondingly reduced. This variant is therefore particularly suitable for a charging process or a rapid charging process, especially for charging the battery at a charging station, where cooling of the passenger compartment is typically not performed or necessary.

[0022] According to a further (second) embodiment, the second cooling medium for cooling the first cooling medium can suitably be supplied to the second heat exchanger from outside the vehicle. A cooled second cooling medium is expediently supplied to the second heat exchanger for cooling from outside the vehicle. The motor vehicle expediently comprises an inlet for the second cooling medium and an outlet for the second cooling medium, wherein the inlet and the outlet are fluidically connected to the second heat exchanger. In summary, the heat exchanger is provided such that, for its operation, the (relatively cold) coolant is supplied to it from outside the vehicle upstream of the second heat exchanger and that the (relatively warm coolant) is discharged downstream of the second heat exchanger to outside the vehicle.

[0023] Therefore, only a (first) part of the cooling medium circuit is arranged in the motor vehicle. The second, remaining section of the cooling medium circuit is connected externally to a reservoir for the second cooling medium. For example, a charging device, particularly designed as a charging station, at which the battery of the motor vehicle can be electrically charged, comprises the reservoir. The reservoir is connected and / or connectable to the inlet and outlet of the motor vehicle. For example, a connection provided for this purpose is integrated into a charging plug, and the inlet and outlet are integrated into a charging socket of the motor vehicle. The charging station also comprises, for example, a heat exchanger for cooling the second cooling medium. This heat exchanger can be provided to cool the cooling medium of several charging stations simultaneously.

[0024] According to a suitable development, the first heat exchanger is structurally integrated into the heat exchanger device, in particular into the second heat exchanger. For example, the first and second heat exchangers are jointly attached to the fan. Additionally or alternatively, the first and second heat exchangers have common cooling fins.

[0025] In particular, according to a further (third) embodiment, the first and second heat exchangers form a common cooler (radiator) designed for two separate cooling circuits. For example, the first and second heat exchangers form a cooler designed in the manner of an integrated water / oil cooler for a motor vehicle. Using such a water / oil cooler, the coolants (for example, oil and water) of two separate coolant circuits can be cooled. The first and second heat exchangers can expediently be cooled simultaneously using the fan.

[0026] A further aspect of the invention relates to a method for operating a motor vehicle which is designed according to one of the variants presented above.

[0027] According to the method—as already described in connection with the vehicle—the first cooling medium of the battery cooling circuit is tempered, in particular cooled, in the first heat exchanger using the heat exchanger device. This cooling process is expediently carried out when the battery is being charged, in particular during a rapid charging process.

[0028] According to a suitable embodiment—as illustrated in connection with the second variant of the motor vehicle—the second cooling medium, in particular one cooled externally, is supplied to the second heat exchanger from outside the vehicle in order to cool the first heat exchanger or the first cooling medium. Thus, the cooled second cooling medium is supplied from outside the vehicle to the second heat exchanger, where it absorbs heat from its surroundings and thus cools the surroundings. The then comparatively warm second cooling medium is then directed back outside the vehicle.

[0029] According to an advantageous embodiment of the method, in order to cool the battery, in particular during a charging process of the battery, air is cooled by means of the second heat exchanger and this air is directed to the first heat exchanger by means of the fan.

[0030] According to an alternative embodiment of the method, in order to cool the battery, in particular during a charging process of the battery, air, in particular ambient air, is directed to the first heat exchanger by means of the fan of the heat exchanger device.

[0031] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1 schematically shows an electrically driven motor vehicle, the battery of which can be cooled by means of a battery cooling circuit, wherein the battery cooling circuit comprises a first heat exchanger and a first cooling medium, and wherein the first cooling medium in the first heat exchanger can be cooled by means of a heat exchanger device for a further cooling medium circuit, Fig. 2 schematically shows a first variant of the motor vehicle, in which a second heat exchanger of the heat exchanger device of the motor vehicle can be supplied with a cooled second cooling medium from a charging station outside the vehicle, Fig. 3 schematically shows a second variant of the motor vehicle, wherein the second heat exchanger of the heat exchanger device is thermally coupled to the first heat exchanger, and wherein the second heat exchanger is a heat exchanger of an air conditioning system of the motor vehicle, and Fig. 4 schematically shows a second variant of the motor vehicle, wherein the second heat exchangers are structurally connected to one another in the manner of a water / oil cooler.

[0032] Corresponding parts and sizes are always provided with the same reference symbols in all figures.

[0033] In the Fig. 1 schematically shows an electrically powered motor vehicle 2, also referred to as a vehicle or motor vehicle. This has a (traction) battery 4 with a plurality of battery cells 6, of which only two are shown as an example. The battery cells are connected in series and / or parallel to one another. An electrical consumer 8, in particular a high-voltage consumer, is connected to the battery 4. The consumer 8 is in particular an inverter which converts the direct voltage or direct current provided by the traction battery 4 into an alternating voltage or alternating current. The inverter 8 is connected to a (traction) electric motor 10 of a traction drive. In summary, the battery 4 provides electrical energy for driving the motor vehicle 2.

[0034] Furthermore, the motor vehicle 2 comprises a charging socket 12 which is electrically connected to the battery 4 for charging the latter.

[0035] For cooling the battery 4, the motor vehicle 2 has a battery cooling circuit 14. This comprises cooling units (cooling devices) 16, designed, for example, as cooling plates, for cooling the battery 4, in particular its battery cells 6. For this purpose, a first cooling medium 18 of the battery cooling circuit 14 can flow through the cooling units 16. A first heat exchanger 20 of the battery cooling circuit 14 is fluidly connected to the cooling units 16, wherein the first cooling medium 18 can be cooled at the first heat exchanger 20. In a manner not shown in detail, the battery cooling circuit 14 comprises a pump for conveying the first cooling medium 18 in the battery cooling circuit 14.

[0036] For cooling the first heat exchanger 20 and thus for cooling the first cooling medium 18 in the first heat exchanger 20, the electrically driven motor vehicle 2 comprises a heat exchanger device 22. This comprises a second heat exchanger 24, a fan 26 for generating an air flow L at the first heat exchanger 20 and / or at the second heat exchanger 24 and a second cooling medium 28 for the second heat exchanger 24, cf. Fig. 2 to 4. In the following, the Fig. 2 to 4 show three variants of the motor vehicle 2, which differ in the cooling of the first cooling medium 18. According to a method for operating the motor vehicle 2, in particular during a charging process of the battery 4, the first cooling medium 18 is tempered, in particular cooled, in the first heat exchanger 20 using the heat exchanger device 22.

[0037] The first heat exchanger 20 and the second heat exchanger 24 are each designed, for example, in the manner of a radiator.

[0038] According to a first variant of the (electrically driven) motor vehicle 2, which is shown in the Fig. 2, the second heat exchanger 24 is connectable to a vehicle-external reservoir 30 for the second cooling medium 28. For this purpose, the motor vehicle 2 has an inlet 32 ​​for the second cooling medium, which is fluidically connected to the second heat exchanger 24, and an outlet 34, which is also fluidically connected to the second heat exchanger 24. The second cooling medium 28 can thus be supplied to the motor vehicle 2 at the inlet 32 ​​and discharged at the outlet, wherein the second heat exchanger 24 is fluidically arranged between the inlet 32 ​​and the outlet 34.

[0039] According to the exemplary embodiment shown here, the inlet 32 ​​and the outlet 34 are representatively integrated into the charging socket 12 of the motor vehicle 2 in a space-saving manner. In this way, both electrical energy and the second cooling medium 28 can be transmitted to the motor vehicle from a charging device 36 designed as a charging station, for example using a common plug 38. For this purpose, the charging plug 38 has corresponding connections 39 for the inlet 32 ​​and for the outlet 42 as well as connections (not shown in detail) for electrically contacting the charging socket 12 for charging the battery. Alternatively, the charging device 36 can be provided with both a charging plug for providing electrical energy and a separate plug for providing the cooled second cooling medium 28.

[0040] The second cooling medium 28 is cooled in the charging device 36. The (third) heat exchanger 40 used for this purpose is designed, for example, to cool the second cooling medium 28 for a plurality of charging motor vehicles.

[0041] The motor vehicle 2 and / or the charging device 36 comprises a pump (not shown in detail) for conveying the second cooling medium 28 in the cooling medium circuit of the heat exchanger device 22.

[0042] The fan 26 of the heat exchanger device 22, the first heat exchanger 20, and the second heat exchanger 24 are arranged relative to one another such that the air flow L generated by the fan 26 directs the air cooled by the second heat exchanger 24 to the first heat exchanger 20. For example, the first heat exchanger 20 and the second heat exchanger 24 are arranged one behind the other with respect to the fan axis. In this way, the first and second heat exchangers 20, 24 are thermally coupled to one another.

[0043] In summary, in the method for operating the motor vehicle of this first variant, the (relatively cold) second refrigerant 28 is supplied to the second heat exchanger 24 via the inlet 32 ​​from outside the vehicle, here from the charging device 36 upstream of the second heat exchanger 24. Consequently, the second heat exchanger 24 and, concomitantly, the first heat exchanger 20 thermally coupled thereto are cooled. The (relatively warm) second refrigerant 28 downstream of the second heat exchanger 24 is discharged to the charging device 36 outside the vehicle.

[0044] Furthermore, according to the method for operating this first variant of the motor vehicle for cooling the battery 4, air is cooled by means of the second heat exchanger 24 and is passed to the first heat exchanger WT by means of the fan 26.

[0045] According to a second variant of the (electrically driven) motor vehicle 2, which is shown in the Fig. 3, the motor vehicle 2 comprises an air conditioning system 42 for air-conditioning a passenger compartment. A heat exchanger of the cooling medium circuit 44 of the air conditioning system 42 is used as the second heat exchanger 24. Analogous to the first variant, the fan 26 of the heat exchanger device 22, the first heat exchanger 20, and the second heat exchanger 24 are arranged relative to one another in such a way that the air flow L generated by the fan 26 directs the air cooled by the second heat exchanger 24 to the first heat exchanger 20, so that the first and second heat exchangers 20, 24 are thermally coupled to one another.

[0046] For example, the second heat exchanger 24 is an evaporator of the air conditioning system, where air is cooled before being directed into the passenger compartment. Alternatively, a heat exchanger, which forms the condenser of the air conditioning system when cooling the passenger compartment, is used as the second heat exchanger. In this alternative, when the motor vehicle is in operation, the air conditioning system 42 is operated like a heat pump, which can transfer heat in both directions, in particular from its first to its second heat exchanger and vice versa. Thus, air is cooled at the heat exchanger, which otherwise forms the condenser for cooling the passenger compartment.

[0047] According to a third variant of the (electrically driven) motor vehicle 2, which is described in the Fig.4, the first heat exchanger 24 is structurally integrated into the heat exchanger device. The first and second heat exchangers 20, 24 are designed in the manner of a water / oil cooler, as is known from the prior art for motor vehicles. A circuit for the first cooling medium 18 and a circuit for the second cooling medium are still separate from one another. Both heat exchangers 20, 24 can be cooled with the ambient air, in particular simultaneously, using the fan. The first and second heat exchangers 20, 24 form, in particular, a structurally connected radiator for these two circuits. For example, pipe sections through which the first cooling medium 18 can flow and pipe sections through which the second cooling medium can flow are accommodated in a common cooling fin structure.

[0048] The cooling of the first cooling medium at the first heat exchanger 20 is carried out here in summary by means of the air flow generated by the fan 26, in particular from uncooled ambient air.

[0049] The second heat exchanger 24 serves in particular for cooling an engine (not shown in detail), especially if the motor vehicle is designed as a hybrid vehicle. The first and second heat exchangers 20 and 24 are preferably arranged side by side with respect to the direction of air flow, so that the heat dissipated by the second heat exchanger 24 is not conducted to the first heat exchanger.

[0050] In all three variants, the first cooling medium 18 is adapted to the specified cooling capacity for the battery 4, and the second cooling medium 28 is adapted to the specified cooling capacity of the second heat exchanger 24. For this purpose, the first and second cooling media 18, 28 are expediently selected to be different. In other words, the first and second cooling media 18, 28 comprise different substances or mixtures of substances.

[0051] The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can be derived from them by those skilled in the art within the scope of the claims without departing from the subject matter of the invention. In particular, all individual features described in connection with the exemplary embodiments and / or in the claims can also be combined with one another in other ways without departing from the subject matter of the invention. List of reference symbols 2 electrically powered motor vehicle 4 Battery 6 battery cells 8 consumers / inverters 10 Electric motor 12 charging socket 14 Battery cooling circuit 16 Cooling device / cooling plate 18 first cooling medium 20 first heat exchanger 22 Heat exchanger device 24 second heat exchanger 26 fans 28 second cooling medium 30 reservoirs 32 Inlet 34 Process 36 Charging device 38 plugs 39 connection 40 third heat exchanger 42 Air conditioning 44 Cooling medium circuit L Airflow

Claims

[1] Electrically powered motor vehicle (2), comprising - a battery (4), in particular designed as a traction battery for a drive, - a battery cooling circuit (14) for the battery (4), with a first heat exchanger (20) and with a first cooling medium (18), and - a heat exchanger device (22) with a second heat exchanger (24) and with a second cooling medium (28), wherein the first coolant (18) in the first heat exchanger (20) can be cooled by means of the heat exchanger device (22). [2] Electrically driven motor vehicle (2) according to claim 1, characterized by that the second heat exchanger (24) is or can be thermally coupled to the first heat exchanger (20). [3] Electrically driven motor vehicle (2) according to claim 1 or 2, characterized bythat the heat exchanger device (22) has a fan (26) for generating an air flow (L) at the first heat exchanger (20) and / or at the second heat exchanger (24). [4] Electrically driven motor vehicle (2) according to one of claims 1 to 3, characterized by that the first cooling medium (18) and the second cooling medium (28) are different cooling media. [5] Electrically driven motor vehicle (2) according to one of claims 2 to 4, characterized by an air conditioning system (42), wherein the second heat exchanger (24) is a heat exchanger of the air conditioning system (42). [6] Electrically driven motor vehicle (2) according to one of claims 2 to 4, characterized by that the second cooling medium (28) for cooling the first cooling medium (18) can be and / or is supplied to the second heat exchanger (24) from outside the vehicle. [7] Electrically driven motor vehicle (2) according to one of the preceding claims, characterized bythat the first heat exchanger (20) is structurally integrated into the heat exchanger device (22), in particular in the manner of a water / oil cooler. [8] Method for operating a motor vehicle (2) designed according to one of claims 1 to 7, wherein the first cooling medium (18) in the first heat exchanger (20) is tempered, in particular cooled, by means of the heat exchanger device (22). [9] Method according to claim 8, characterized by that the second cooling medium (28) is supplied to the second heat exchanger (24) from outside the vehicle, in particular from a charging station (36) for charging the battery (4). [10] Method according to claim 8 or 9, characterized by in that, in order to cool the battery (4), in particular during a charging process of the battery (4), air is cooled by means of the second heat exchanger (24) and this air is directed to the first heat exchanger (20) by means of the fan (26).

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