CN110239308B - Air conditioning system for a motor vehicle with a heat pump and method for operating such a heat pump - Google Patents

Abstract

The invention relates to an air conditioning system for a motor vehicle with a heat pump, wherein the heat pump has a battery-heat transfer unit (6), which is thermally coupled to the battery of the motor vehicle, wherein the battery-heat transfer unit (6) ) acts as a liquefier or gas cooler in the operating mode of the heat pump for dissipating heat to the battery. Furthermore, the invention relates to a method for operating such an air-conditioning device ( 1 , 1 ′, 1 ″).

Description

Air-conditioning device for a motor vehicle with heat pump and method for operating such a heat pump

technical field

The invention relates to an air conditioning system for a motor vehicle, in particular a hybrid or electric vehicle, with a heat pump which enables heating of a battery, in particular a traction battery of the motor vehicle. Furthermore, the invention relates to a method for operating a heat pump of such an air-conditioning system.

Background technique

In the field of vehicle development, the focus is now on the efficient electrification of the drive train (Antriebsstrang, sometimes also referred to as the drive train) of the motor vehicle. Electrification requires in particular the use of high-voltage batteries (HV-batteries).

In order to be able to utilize the power of the battery optimally and to protect the battery from aging effects and damage, the temperature of the battery should be kept in a temperature range between 15°C and 30°C. Therefore, high-voltage batteries are usually cooled during operation in order to avoid overheating. It may also be necessary to heat the battery in cold environments.

For this reason, water cooling of the high-voltage battery is often used in conjunction with heaters, for example so-called PTC heaters (PTC-Positive Temperature Coefficient) in the water circuit. For example, DE 10 2015 103 032 A1 discloses a system for thermal management of a motor vehicle, which has a series of cooling or coolant circuits. One of the coolant circuits is used to cool the vehicle battery, and a battery heater, for example a 12V electric heater, is additionally integrated for heating the coolant before it flows through the battery. Document DE 10 2013 114 307 A1 also describes a similar heating and cooling system.

When using a heater, the entire water circuit must be heated in addition to the battery, which reduces the efficiency of the heating method. Furthermore, the installation of the heater results in an additional installation space requirement and excess weight in the vehicle.

Alternatively, heating of the cell may be performed by electrical heating elements incorporated therein (eg heated pads, wires and the like). The electrical heating elements within the battery in turn cause additional costs in the overall very cost-sensitive components of the high-voltage battery.

The entirety of this heating method is often powered by the high-voltage battery itself. The amount of energy required for this is then no longer available for the driving function and the vehicle mileage is thus reduced.

Contents of the invention

The object of the present invention is to provide an air-conditioning system and a method for operating a heat pump of an air-conditioning system which at least partially overcome the above-mentioned disadvantages.

This object is solved by the air conditioning system and the method for operating a heat pump described below.

According to a first aspect, the invention relates to an air-conditioning system for a motor vehicle with a heat pump, wherein the heat pump has a battery-heat transfer unit thermally coupled to a battery of the motor vehicle, wherein the battery-heat transfer unit is in the operating mode of the heat pump The neutral acts as a liquefier or gas cooler for dissipating heat to the battery.

According to a second aspect, the invention relates to a heat pump for operating an air-conditioning system of a motor vehicle, wherein the regulating unit (Stellorgane) of the heat pump is adjusted in such a way that the battery-heat exchanger of the heat pump (which is connected to the battery heat exchanger of the motor vehicle) coupling) in the first operating mode as a liquefier or gas cooler for delivering heat to the battery and in the second operating mode as an evaporator for receiving heat from the battery.

Further advantageous embodiments of the invention result from the following description of preferred exemplary embodiments of the invention.

The invention relates to an air-conditioning device for a motor vehicle, for example a hybrid vehicle or an electric vehicle, each with an electric drive machine. The air-conditioning system includes a heat pump, which is designed in particular as a coolant circuit. The coolant circuit preferably has a coolant such as 2,3,3,3-tetrafluoropropene (R1234yf), carbon dioxide (R744) or other coolants flowing through it. The heat pump has a battery heat exchanger which is thermally coupled to the battery of the motor vehicle. The battery may be a high-voltage battery of the motor vehicle, for example a traction battery of the motor vehicle, for supplying an electrically driven machine of the motor vehicle.

In the operating mode of the heat pump, in particular at least in the first operating mode of the heat pump, the battery heat exchanger acts as a liquefier (condenser) or gas cooler for supplying heat to the battery, in particular as coolant liquefaction device. The battery thus forms the radiator of the heat pump at least in the first operating mode.

The battery can thus be heated via a heat pump in the motor vehicle. In this case, the battery heat exchanger is preferably integrated directly into the coolant circuit and is not accommodated in the coupled cooling circuit. Since heat pumps can generally be operated with a COP (coefficient of performance) > 1, such a heating function can be more efficient than purely electric heating according to the prior art.

In some exemplary embodiments, the battery heat exchanger can function as an evaporator for receiving heat from the battery, in particular as a coolant evaporator, in a further operating mode of the heat pump, in particular at least in a second operating mode of the heat pump. Depending on requirements, in particular depending on the external temperature and the load on the battery, the battery can thus be heated or cooled via the same coolant circuit, wherein an additional heating element for heating the battery can be dispensed with.

In some exemplary embodiments, the heat pump can have a control unit, for example a shut-off valve, which is arranged in such a way that the coolant flows through the battery-heat exchanger in the first position of the control unit in such a way that the battery-heat exchanger acts as a liquefaction The cooler or the gas cooler, and the coolant flows through the battery heat exchanger in the second position of the conditioning unit in such a way that the battery heat exchanger acts as an evaporator. Preferably, the regulating unit is in its first position at least in a first operating mode of the heat pump and in its second position at least in a second operating mode of the heat pump, wherein the regulating unit is between the first and second operating modes The adjustment of leads to a flow reversal (Strömungsumkehr).

For example, a shut-off valve can be arranged in flow direction upstream of the compressor and node of the heat pump, via its compressor being connected to an external heat exchanger, for example a condenser, for receiving heat from the surroundings. In the first position of the shut-off valve in which the shut-off valve is closed, heated coolant can flow through the open first flow branch for giving heat to the interior at the interior of the motor vehicle (vehicle interior)— The heat exchanger then flows directly through the battery heat exchanger and then through the outer heat exchanger for heating the battery. In the first position of the shut-off valve, the second flow branch via which the heated coolant can likewise flow into the battery heat exchanger can be closed. In the second position of the shut-off valve in which the shut-off valve is open, the coolant, after flowing through the interior heat exchanger for delivering heat to the vehicle interior, can pass through the now open second flow branch for cooling the battery. The coolant that flows through the battery-heat exchanger and is heated by the battery-heat exchanger then flows through the open shut-off valve directly to the compressor. In the second position of the shut-off valve, the first flow branch is preferably closed. Through the shut-off valve and the adjustment of the first valve in the first flow branch and the second valve in the second flow branch, thus passing through the battery-heat exchanger (ie preferably in the battery or battery-cooler) ) can occur, so that in the first position of the shut-off valve an additional heat supply takes place in the battery, in both cases first the interior—after the heat exchanger has been flowed through.

In some exemplary embodiments, the heat pump can also have a compressor and an interior heat exchanger for directly or indirectly supplying heat to the interior of the motor vehicle. Preferably, the heat pump may be a heat pump integrated in particular in the motor vehicle, primarily for heating the cabin and additionally for heating the battery, in particular the high-voltage battery. The compressor can have an electric motor, which can be supplied with electrical energy preferably via a vehicle network, for example a 12V vehicle system or a 400V system. The inner-heat transferor can be a water-coolant-heat transferr for transferring heat to the coolant circuit coupled with the coolant cycle, a coolant-air-heat transferr (which transfers heat directly from the coolant given to the air of the circulating inner-heat transferr) or other inner-heat transferr. The internal heat transfer device can be arranged downstream of the compressor and upstream of the battery heat transfer device in the flow direction of the coolant circuit. The coolant thus heated can first flow through the inner heat exchanger, which absorbs part of the heat and cools the coolant slightly, and then flows at a lower temperature through the battery heat exchanger.

In some embodiments, the heat pump can be constructed so that the coolant gives heat in the inner-heat transfer device for so long until the temperature of the coolant reaches the boiling temperature of the coolant, and the coolant is then at the boiling temperature In this case the flow is through the battery-heat exchanger. Thus two parts of the heat are given. Since the coolant can be superheated by compression with the aid of a compressor, that is to say can have a temperature above the boiling temperature, it can give up heat in the internal heat exchanger until the temperature reaches the boiling temperature . The coolant then flows through the battery heat exchanger at boiling temperature. Overheating of the battery can thus be prevented and the battery heated uniformly, since the boiling temperature is maintained for a certain time during heat delivery.

In some embodiments the heat pump may have a controllable decompression unit arranged between the interior-heat transfer unit and the battery-heat transfer unit, wherein the controllable decompression unit is configured to reduce the heat in the battery-heat transfer unit. pressure in the area of the transmitter. The pressure-relief unit can be a valve, preferably a valve with a variable cross-sectional opening. The valve can be designed to reduce the pressure in the coolant circuit, which leads to a reduction in the boiling temperature of the coolant. In this way, both heating at lower temperatures and evaporation of the coolant at lower temperatures can be achieved on the one hand.

The controllable pressure reduction unit can be designed to reduce the pressure in the region of the battery heat exchanger such that the boiling temperature of the coolant lies in the range between 0° C. and 30° C., preferably 20° C. to 30° C. in the range. A two-stage heat release can thus be produced, with the inner heat transfer gas cooled and possibly condensed at high pressure levels, especially in the case of condensation temperatures in the range of 40° C. to 80° C., for example at At a condensation temperature of 60° C., heat is given off, and the battery heat exchanger immediately after throttling condenses at low pressure at a condensation temperature in the range of 20° C. to 30° C., for example at In the case of a condensation temperature of 25° C., heat is given to the battery evenly.

In some exemplary embodiments, the heat pump can alternatively be configured in such a way that the coolant flows from the interior heat transfer device to the battery heat transfer device without being actively throttled there. Preferably, in this case no pressure reduction unit and thus no active throttle is provided between the internal heat exchanger and the battery heat exchanger. The pressure levels in the area of the inner heat exchanger and the battery heat exchanger can therefore be substantially the same and vary only due to pressure losses in the lines. For example, the pressure difference between the area of the inner heat exchanger and the area of the battery heat exchanger can be less than 15 bar. When the coolant is R1234yf, the pressure difference may be less than 2 bar, and when the coolant is R744, the pressure difference may be less than 10 bar. Thus, a somewhat equal heat transfer can be produced in two stages, wherein the inner heat transfer unit dissipates heat in a gas-cooled and partially condensed manner with a recognizable temperature difference and the battery heat transfer unit subsequently condenses Heat is delivered to the battery without significant temperature differences. A uniform heating of the battery can thus also be achieved without a throttle.

In some exemplary embodiments the heat pump can additionally have an interior-air-coolant-heat transfer unit which is arranged in the coolant circuit of the heat pump in such a way that it runs parallel to the battery-heat transfer at least in the first operating mode of the heat pump The coolant flows through the device while giving heat. The coolant flow through the heat pump can thus be used not only to efficiently heat the interior of the motor vehicle but also to heat the battery.

Heat pumps can also dispense with interior-heat transfer and interior-air-coolant-heat transfer. In this case, the battery heat exchanger can be connected directly after the compressor into the coolant circuit and produces a single-stage heat supply to the battery without simultaneous heating of the cabin. However, the heating of the vehicle interior can therefore not be achieved in the same coolant circuit and, moreover, the heating temperature and the uniformity of the heating can only be achieved with difficulty.

In some embodiments the battery-heat transfer device can be a phase change structure (Phasenwechselstruktur) arranged in and/or at the battery or a heat exchanger for introducing heat into a cooling circuit flowing through the battery, for example a battery-cooling Device (Batterie-Chiller). When implementing coolant evaporative cooling for batteries, evaporator structures are often introduced in the battery interior, in which direct evaporation of the coolant of the vehicle air-conditioning system takes place during cooling operation. In this way, a cooling effect on the battery can be achieved without an additional liquid cooling circuit. The coolant evaporator can then also be used directly for heating the battery during heat pump operation of the air conditioning system. Alternatively, heat can also be taken via a separate heat exchanger (cooler) into the water circuit, which flows through the battery. Preferably, a water circuit is used here, which is maintained for battery cooling anyway.

The heat pump can have a further adjustment unit and a further controllable pressure reduction unit. The adjustment unit and the controllable pressure reduction unit of the heat pump can be actuated by means of electric actuators supplied with electrical energy via the on-board network of the motor vehicle.

In summary, current air-conditioning systems enable very efficient heating of the battery via heat pump function with COP > 1, division of heating power between cabin and battery (thus taking into account interior comfort) and via two stages of heat pump The adjustable temperature level for the battery of operation, ie the optimal operating conditions for the battery can be adjusted (temperature level and temperature uniformity).

Furthermore, the invention relates to a method for operating a heat pump, for example a heat pump, of an air-conditioning system of a motor vehicle, as described in detail above. According to the method, the control unit of the heat pump is adjusted in such a way that the battery heat exchanger of the heat pump, which is thermally coupled to the battery of the motor vehicle, acts as a liquefier or gas cooler in the first operating mode for supplying heat to the battery. and function as an evaporator for receiving heat from the battery in the second operating mode.

In some exemplary embodiments in the first operating mode the pressure in the region of the battery heat exchanger can be reduced such that the boiling temperature of the coolant lies in the range between 0° C. and 30° C., preferably at 20° C. to the range of 30°C. To this end, the controllable pressure reduction unit arranged between the interior heat exchanger and the battery heat exchanger can be adjusted accordingly. A two-stage heat transfer can thus be achieved, with the inner heat transfer gas cooled and possibly condensed at high pressure levels, especially in the case of condensation temperatures in the range of 40° C. to 80° C., for example at At a condensation temperature of 60° C. heat is given off and the battery heat transfer unit is condensed immediately after throttling at low pressure at a condensation temperature in the range of 20° C. to 30° C., for example at 25° C. In the case of a condensation temperature of 0° C., heat is given to the battery evenly.

The entry point of the coolant into the battery heat exchanger, ie into the battery or battery cooler, especially the relationship between pressure, water content and temperature can be given by the heat at the inner heat exchanger and can be Controlled adjustment of the opening cross-section of the decompression unit. Ideally, this point should lie on the dew point line (Taulinie) (condensation curve) of the enthalpy-pressure-schematic diagram, for example a logarithmic enthalpy-pressure-schematic diagram, so that at the temperature of the battery-heat exchanger As much heat as possible can enter the battery through a phase change of the coolant without the coolant undergoing a temperature change here.

The heat pump can also be operated in a further operating mode in which the battery-heat exchanger acts as an evaporator for receiving heat from the battery or is not used.

Description of drawings

Embodiments of the invention are now described by way of example and with reference to the drawings. in:

Figure 1 schematically shows a first embodiment of an air conditioning device for a motor vehicle;

Figure 2 shows a first relationship between enthalpy and pressure during the flow cycle of the coolant;

Figure 3 shows a second relationship between enthalpy and pressure during the flow cycle of the coolant;

Figure 4 schematically shows a second embodiment of an air-conditioning device for a motor vehicle; and

FIG. 5 schematically shows a second exemplary embodiment of an air-conditioning device for a motor vehicle.

List of reference symbols

1,1',1'' air conditioner

2 coolant circuits

3 compressors

4 Internal space - liquefier

4' Water-Coolant-Heat Transmitter

5a, 5b, 5c, 5d pressure reducing valve

6 Batteries - Heat Transmitter

7a, 7b, 7c, 7d, 7e Stop valve

8 External - evaporator

8' External - Heat Spreader

9 air flow

10,13,14,15,18,19 nodes

11,12,17 Branches of the coolant circuit

16 Internal space - heat transfer device

20 internal heat transfer

21 Collector (Sammler)

22 Coolant circuit

23 electric heating element

24 heating - heat transfer device

25 pumps.

Detailed ways

FIG. 1 shows a first exemplary embodiment of an air-conditioning system 1 of a motor vehicle. The air-conditioning device 1 comprises a coolant circuit 2 which forms a heat pump. The coolant circuit 2 includes a compressor 3, an inner space-liquefier 4, a first pressure-reducing valve 5a and a second pressure-reducing valve 5b, a battery-heat transfer device 6, a first shut-off valve 7a, a second shut-off valve 7b and a second shut-off valve. Three shut-off valves 7c and external - evaporator 8.

Compressor 3 compresses heated coolant like 2,3,3,3-tetrafluoropropene (R1234yf) or carbon dioxide (R744), which flows to compressor 3 from external space - evaporator 8 or from battery - heat exchanger 6 . Interior space - liquefier 4 , which is arranged in flow direction after compressor 3 and extracts heat from the heated and compressed coolant and delivers it to air flow 9 flowing in the direction of the passenger compartment of the motor vehicle and Heated passenger compartment. The first pressure relief valve 5 a is arranged downstream of the interior space liquefier 4 in flow direction and serves to reduce the pressure of the coolant. By reducing the pressure the boiling temperature of the coolant also decreases.

At a first node 10 after the first pressure reducing valve 5 a in the flow direction, the cooling circuit is divided into a first branch 11 and a second branch 12 . A first shut-off valve 7 a, a second node 13 and a second shut-off valve 7 b are arranged in the first branch 11 . The first branch 11 opens into a third node 14 at which the first branch 11 joins the second branch 12 . Arranged in the second branch 12 is a third shut-off valve 7 c , a fourth node 15 , a second pressure reducing valve 5 b and the external evaporator 8 . The battery-heat exchanger 6 is arranged between the second node 13 and the fourth node 15 so that coolant can flow from the second node 13 or the fourth node 15 to the battery-heat exchanger 6 .

In the first operating mode of the air-conditioning device 1 , the first shut-off valve 7 a is open and the second shut-off valve 7 b and the third shut-off valve 7 c are closed. Thus, the coolant flows from the inner space-liquefier 4 through the first pressure-reducing valve 5a and along the first branch 11 through the first shut-off valve 7a into the battery-heat exchanger 6, which Additional heat is extracted from the coolant throttled in the first pressure relief valve 5 a and thus heats up the battery of the motor vehicle. The battery heat exchanger 6 thus acts in the first operating mode as a liquefier and thus as an additional heat sink (Wärmesenke, sometimes also referred to as a heat sink) of the air conditioning system.

The superheated coolant entering the interior liquefier 4 is cooled by the heat in the interior liquefier 4 to approximately the boiling temperature given the pressure in the interior liquefier 4 , here approximately 60°C. The pressure is reduced in the first pressure reducing valve 5a and the boiling temperature of the coolant drops to approximately 25°C. At this temperature the battery heats up so uniformly.

The coolant then flows via the fourth node 15 to the outer evaporator 8 through the second pressure reduction valve 5 b , which further reduces the pressure. External - The evaporator 8 receives heat from the ambient air in order to heat the coolant in the case of low pressure where the boiling temperature is reduced.

FIG. 2 shows an example of a first relationship between enthalpy H and pressure during a flow cycle of the coolant through the coolant circuit, the pressure-axis being scaled logarithmically. In this case, the enthalpy increases with increasing pressure in the compressor 3 , as indicated in A. The enthalpy gain at a constant pressure then takes place in the interior liquefier 4 at the first pressure p ₁ , as indicated in B. The pressure drops in the first pressure reducing valve 5 a without changing the enthalpy here, as indicated in C. The enthalpy given in the case of a constant pressure is then generated in the case of a second pressure p ₂ which is lower than the first pressure p ₁ in the cell-heat exchanger 6 operating as a liquefier, as indicated in D like that. The pressure then drops in the second pressure relief valve 5 b to a third pressure p ₃ , which is lower than the second pressure p ₂ , as indicated in E. In the case of the third pressure in the external evaporator 8 an increase in enthalpy occurs, as indicated in F.

This results in a two-stage heat release, in which heat is released in the interior liquefier 4 at a high pressure level with the gas cooled and possibly condensed and then the battery is heated at a low pressure level. This makes it possible to reliably and uniformly heat the battery at a suitable temperature.

Alternatively, the first relief valve may be fully opened or omitted. In this case the coolant flows unthrottled through the first shut-off valve 7 a and the second node 13 into the battery heat exchanger 6 . The battery heat exchanger 6 acts again as a liquefier, which dissipates heat to the battery and forms an additional heat sink for the air-conditioning device 1 .

The superheated coolant entering the interior liquefier 4 is cooled by heat given in the interior liquefier 4 , which results in the coolant flowing into the interior liquefier 4 and liquefied from the interior liquefier The temperature difference between the coolant flowing out of the device 4. Subsequently, coolant with a reduced temperature flows through the battery-heat exchanger 6 , the temperature remaining substantially constant. At this temperature, the battery heats up so uniformly. The further flow course of the coolant corresponds to the course described above through the second pressure relief valve 5 b and the outer evaporator 8 .

FIG. 3 shows an example of a second relationship between enthalpy and pressure during a flow cycle of the coolant through the coolant circuit, the pressure-axis being scaled logarithmically. In this case, the enthalpy increases with increasing pressure in the compressor 3 , as indicated in A′. The enthalpy at a constant pressure then occurs at the first pressure p ₁ in the interior liquefier 4 , as indicated in B′. A further enthalpy emission then takes place at the first pressure in the cell heat exchanger 6 operating as a liquefier, as indicated in C′. The pressure then drops in the second pressure relief valve 5 b to a second pressure p ₂ , which is lower than the first pressure p ₁ , as indicated in D′. In the external evaporator 8 , an enthalpy increase occurs at the second pressure, as indicated in E′.

This results in a two-stage heat release, in which the gas cools and partially condenses heat into the interior (with temperature difference) and then condenses (without significant temperature difference) into the battery .

In the second operating mode of the air-conditioning device 1 , the first shut-off valve 7 a is closed and the second shut-off valve 7 b and the third shut-off valve 7 c are open. The coolant flows via the second branch 12 via the fourth node 15 to the battery-heat exchanger 6 which extracts heat from the battery and cools it. In the second operating mode, the battery-heat exchanger 6 thus acts as an evaporator and forms a cold sink (Kältefalle, sometimes also referred to as condenser) of the air-conditioning device 1 .

FIG. 4 shows a second exemplary embodiment of an air-conditioning device 1' for a motor vehicle. The air conditioning device 1' is based on the principle of the air conditioning device 1 of the first embodiment. In addition, the air-conditioning device 1 ′ comprises an interior heat exchanger 16 which is arranged in the second branch 12 upstream of the fourth node 15 and together with the interior liquefier 4 forms an air conditioner (Klimagerät) (shown as a dashed box). Instead of the external evaporator 6 , an external heat transfer device 6 ′ is provided, which can function not only as an evaporator but also as a liquefier. Furthermore, a third pressure relief valve 5c is arranged in the second branch 12 before the fourth node 15 and a fourth pressure relief valve 5d is arranged between the fourth node and the battery-heat exchanger 6'.

The air-conditioning device 1' furthermore comprises a third branch 17 which branches off at a fifth node 18 between the inner space-liquefier 4 and the first pressure-reducing valve 5a and at the outer-heat exchanger 8 ′ and the fifth shut-off valve 7e opens into the second branch 12 at the sixth node 19 . A fourth shut-off valve 7d is located in the branch.

After the second pressure reducing valve 5 b , the second branch 12 is led through the inner heat exchanger 19 arranged between the third node 14 and the compressor 3 and then into the outer heat exchanger 8 ′. A fifth shut-off valve 7e is arranged between the sixth node 19 and the third node 14 and a collector 21 is also arranged between the third node 14 and the inner heat exchanger 20 .

In the first operating mode, the first shut-off valve 7 a and the fifth shut-off valve 7 e are open, while the second shut-off valve 7 b and the fourth shut-off valve 7 d are closed. As in the first embodiment, the coolant flows through the inner space - the liquefier 4 , through the battery - the heat exchanger 6 and then through the outer - the heat exchanger 6 ′. As described in detail with reference to the first exemplary embodiment, in the second exemplary embodiment a two-part heat supply is also produced, so that the battery can be heated uniformly at a suitable temperature.

In the second operating mode, the first shut-off valve 7 a , the fourth shut-off valve 7 d and the fifth shut-off valve 7 e as well as the second pressure-reducing valve 5 b are closed and the second shut-off valve 7 b is opened. The coolant flows through the interior-liquefier 4 and the interior-heat exchanger 16 and is throttled in the fourth pressure reducing valve 5d. The throttled coolant reaches the battery-heat exchanger 6 where it receives heat from the battery in order to cool the battery. The cooled coolant further flows through the second shut-off valve 7b, the collector 21 and the internal heat transfer device 20 to the compressor 3 .

In the third operating mode, the first shut-off valve 7a, the second shut-off valve 7b and the fourth shut-off valve 7d are closed and the fifth shut-off valve 7e is opened. In this operating mode, the coolant flows through the interior space - liquefier 4 and the interior space - heat exchanger 16 , is throttled in the second pressure reducing valve 5b and in the heat receiver (Wärmeaufnahme, sometimes called endothermic) Down flow external - heat spreader 8'. In this operating mode, no coolant flows through the battery heat exchanger 6 and the battery is accordingly neither cooled nor heated.

In the fourth operating mode, the first shutoff valve 7a, the second shutoff valve 7b and the fourth shutoff valve 7d are open and the fifth shutoff valve 7e and the first pressure reducing valve 5a are closed. The coolant flows through the inner space liquefier 4 , the third branch 17 and reaches the outer heat exchanger 8 ′, which extracts heat from the coolant and gives it to the environment. The cooled coolant is throttled by the second pressure relief valve 5 b and guided in parallel through the interior-heat exchanger 16 or the battery-heat exchanger 6 . In this operating mode, the battery heat exchanger 6 is used as an evaporator for cooling the battery. In parallel, the passenger compartment is air-conditioned.

In the fifth operating mode, the first shutoff valve 7a and the fifth shutoff valve 7e and the first pressure reducing valve 5a are closed and the second shutoff valve 7b and the fourth shutoff valve 7d are opened. The coolant flows through the inner space liquefier 4 , the third branch 17 and reaches the outer heat exchanger 8 ′, which extracts heat from the coolant and gives it to the environment. The cooled coolant is throttled by the second pressure relief valve 5 b and guided through the battery heat exchanger 6 . In this operating mode, the battery heat exchanger 6 acts again as an evaporator for cooling the battery.

FIG. 5 shows a third exemplary embodiment of an air-conditioning device 1 ″ of a motor vehicle. The air conditioning device 1 ″ is based on the principle of the air conditioning device 1 ′ of the second embodiment. Instead of the interior space liquefier 4 , a water-coolant heat exchanger 4 ′ is provided, which delivers heat to the coolant circuit 22 . The coolant circuit 22 comprises an electric heating element 23, a heating-heat transfer device 24 (which together with the interior space-heat transfer device 16 forms the air conditioner of the motor vehicle (shown as a dashed box)) and a pump 25.

The operation modes of the air conditioning device 1 ″ are similar to the first to fifth operation modes of the second embodiment.

Claims (10)

1. An air conditioning device for a motor vehicle with a heat pump, wherein the heat pump has a battery-heat exchanger (6) which is thermally coupled to a battery of the motor vehicle,

wherein the battery heat exchanger (6) acts as a liquefier or a gas cooler for giving heat to the battery in the operating mode of the heat pump, wherein the heat pump furthermore has a compressor (3) and an internal heat exchanger (4, 4 ') for giving heat to the interior of the motor vehicle, wherein the internal heat exchanger (4, 4 ') is arranged downstream of the compressor (3) and upstream of the battery heat exchanger (6) in the flow direction, wherein in the operating mode of the heat pump a coolant flows firstly through the internal heat exchanger (4, 4 ') and then through the battery heat exchanger (6) for two-stage heat giving.

2. An air conditioning unit according to claim 1, wherein the battery-heat exchanger (6) acts as an evaporator for receiving heat from the battery in a further mode of operation of the heat pump.

3. An air conditioning device according to claim 2, wherein the heat pump has a regulating unit (7 b) which is arranged such that the coolant flows through the battery-heat transmitter (6) in a first position of the regulating unit (7 b) such that the battery-heat transmitter (6) acts as a liquefier or a gas cooler, and the coolant flows through the battery-heat transmitter (6) in a second position of the regulating unit (7 b) such that the battery-heat transmitter (6) acts as an evaporator.

4. An air-conditioning device according to any of the preceding claims, wherein the heat pump is configured such that the coolant gives heat in the internal-heat exchanger (4, 4') so long that the temperature of the coolant reaches the boiling temperature of the coolant, and the coolant then flows through the battery-heat exchanger (6) in the case of the boiling temperature.

5. An air conditioning device according to any of the preceding claims 1-3, wherein the heat pump has a controllable pressure reducing unit (5 a) arranged between the internal-heat-exchanger (4, 4') and the battery-heat-exchanger (6), wherein the controllable pressure reducing unit (5 a) is configured for reducing the pressure in the region of the battery-heat-exchanger (6).

6. An air conditioning unit according to any of the preceding claims 1-3, wherein the heat pump is configured such that the coolant flows from the internal-heat exchanger (4, 4') to the battery-heat exchanger (6), where it is not actively throttled.

7. An air-conditioning unit according to any of the preceding claims 1-3, wherein the heat pump furthermore has a further interior space-air-coolant-heat exchanger (16) which is arranged such that it flows through the coolant in parallel to the battery-heat exchanger (6) given heat.

8. An air conditioning device according to any of the preceding claims 1-3, wherein the battery-heat transmitter (6) is a phase change structure arranged in and/or at the battery or is a heat exchanger for introducing heat into a cooling circuit flowing through the battery.

9. A method for operating a heat pump of an air-conditioning device (1, 1',1 ") of a motor vehicle, wherein a conditioning unit (7 b) of the heat pump is adjusted in such a way that a battery-heat transmitter (6) of the heat pump thermally coupled to a battery of the motor vehicle acts as a liquefier or gas cooler for giving heat to the battery in a first operating mode and as an evaporator for receiving heat from the battery in a second operating mode, wherein the heat pump furthermore has a compressor (3) and an internal-heat transmitter (4, 4') for giving heat to an interior space of the motor vehicle, wherein in the first operating mode the internal-heat transmitter (4, 4 ') is arranged after the compressor (3) and before the battery-heat transmitter (6) in a flow direction, wherein in the first operating mode a coolant flows first through the internal-heat transmitter (4, 4') and then through the battery-heat transmitter (6) for giving heat in two stages.

10. The method according to claim 9, wherein in the first operating mode the pressure in the region of the battery-heat exchanger (6) is reduced such that the boiling temperature of the coolant lies in the range between 0 ℃ and 30 ℃.

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