Method for controlling a cooling arrangement for cooling a motor vehicle battery and control device

Abstract

The invention relates to a method for controlling a cooling arrangement (14) for cooling a battery (22) of a motor vehicle (10), wherein the cooling arrangement (14) comprises a coolant circuit (18) through which a coolant flows, with a cooling device (24) for the battery (22), a refrigerant circuit (20) through which a refrigerant flows, and a heat exchanger (34) via which the refrigerant circuit (20) and the coolant circuit (18) are thermally coupled or can be coupled, wherein a control device (16) in a first operating mode (B1) controls the cooling arrangement (14) according to a first cooling mode (M1) such that a first refrigerant temperature (T1) of the refrigerant is set at the heat exchanger (34).In this process, the control unit (16) switches to a second cooling mode (M2) when a second operating mode (B2) is present, according to which it controls the cooling arrangement (14) in such a way that at least temporarily a second refrigerant temperature (T2) of the refrigerant is set at the heat exchanger (34), which is lower than the first refrigerant temperature (T1).

Description

[0001] The invention relates to a method for controlling a cooling arrangement for cooling a motor vehicle battery by means of a control device, wherein the cooling arrangement comprises a coolant circuit through which a coolant flows, including a cooling device for cooling the battery, and a refrigerant circuit through which a refrigerant flows, and a heat exchanger via which the refrigerant circuit and the coolant circuit are thermally coupled or can be coupled to each other for transferring heat from the coolant circuit to the refrigerant circuit. In a first operating mode, the control device controls the cooling arrangement according to a first cooling mode such that a first refrigerant temperature of the refrigerant at the heat exchanger is set. The invention further relates to a control device for a motor vehicle.

[0002] A vehicle battery, such as a high-voltage battery, may need to be cooled to maintain its operating temperature within a permissible range. In certain situations, such as fast charging, the battery heats up particularly quickly and significantly. In these situations, conventional cooling systems typically cool the battery relatively slowly or limit the temperature increase to a limited extent. Consequently, the battery's full capacity and / or maximum charging power can often only be utilized to a limited degree. Therefore, a more efficient or faster cooling method for such batteries would be desirable, especially in these situations.

[0003] Furthermore, systems are known from the prior art according to which coolant from a charging station or charging column can be used during the charging process of a motor vehicle battery by connecting the motor vehicle to such an external cooling circuit.

[0004] DE 10 2020 208 550 A1 describes a method for controlling a volume flow of a coolant between a charging station and an electrically powered vehicle by an external coolant circuit, according to which the volume flow is controlled depending on a cooling requirement of the vehicle.

[0005] WO 2022 / 090425 A1 describes a method for monitoring a coolant connection between a charging infrastructure and a motor vehicle, wherein, after prior verification of a coolant connection, it is supplied with a liquid coolant, and a coolant is supplied to and discharged from a cooling device of the charging infrastructure to the motor vehicle via the coolant connection.

[0006] Such measures are only available when the vehicle is being charged at a charging station and the charging station is equipped with such a cooling system. In other situations, this type of external cooling cannot be used.

[0007] Furthermore, DE 10 2022 210 733 A1 describes a method for carrying out a charging process of a battery, wherein a first heat exchanger of a first cooling circuit is arranged upstream of a second heat exchanger of a second cooling circuit in the direction of travel of the motor vehicle, which in turn is thermally coupled to the battery, and wherein the first heat exchanger is at least temporarily bypassed or blocked during the charging process or is operated with a reduced flow rate.

[0008] The object of the present invention is to provide a method and a control device that enable, at least temporarily, the strongest possible cooling of a motor vehicle battery.

[0009] This problem is solved by a method and a control device with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0010] In an inventive method for controlling a cooling arrangement for cooling a motor vehicle battery with a control device, in which the cooling arrangement comprises a coolant circuit through which a coolant flows, a cooling device for cooling the battery, a refrigerant circuit through which a refrigerant flows, and a heat exchanger via which the refrigerant circuit and the coolant circuit are thermally coupled or can be coupled to each other for transferring heat from the coolant circuit to the refrigerant circuit, the control device, in the presence of a first operating mode, controls the cooling arrangement according to a first cooling mode such that a first refrigerant temperature of the refrigerant is set at the heat exchanger.Furthermore, if a second operating mode is present, the control unit switches to a second cooling mode, according to which the control unit controls the cooling arrangement in such a way that at least temporarily a second refrigerant temperature of the refrigerant at the heat exchanger is set, which is lower than the first refrigerant temperature.

[0011] By at least temporarily lowering the refrigerant temperature, more heat can be extracted from the cooling circuit, thereby cooling the battery more effectively via the cooling system. Typically, when setting the refrigerant temperature on such a heat exchanger, which thermally couples the cooling and refrigerant circuits, excessively low temperatures are avoided to prevent excessively large temperature differences between the cells. The invention is based, in particular, on the understanding that a slightly increased cell temperature difference, provided it is not excessively large, can be safely accepted, at least temporarily, to achieve more effective and rapid battery cooling.In normal operating situations, i.e., in the first operating mode, the refrigerant temperature at the heat exchanger can be set to a higher value, namely the first refrigerant temperature, and in particular regulated to it. In the second operating mode, in which, for example, the strongest and / or fastest possible cooling of the battery is desired, the refrigerant temperature can be lowered to a significantly lower value, namely the second refrigerant temperature, or regulated to it. This ultimately allows for better or shorter cooling times, and by conditioning the battery to lower temperatures, the vehicle's performance can be improved, at least temporarily. Thus, in certain situations, such as during fast charging, better, i.e.,shorter loading times or better lap times in other situations where the highest possible performance is desired, for example on a race track.

[0012] The battery could, for example, be a high-voltage battery from a motor vehicle. The battery can contain multiple battery cells, which could, for example, be lithium-ion cells.

[0013] The cooling arrangement can be designed such that a coolant flows through the coolant circuit during operation, and a refrigerant flows through the refrigerant circuit during operation. The coolant can be a liquid or gaseous coolant, preferably a liquid coolant. The coolant remains liquid at all times while circulating in the coolant circuit. The coolant circuit can also be referred to as a cooling circuit, cooling circuit, or refrigerant circuit.

[0014] The refrigerant circulating in the refrigerant circuit during operation can exist in different phases, for example, in a gaseous phase, a mixed liquid-gas phase, and a liquid phase. The refrigerant circuit can also be referred to as a refrigeration circuit or refrigerant cycle. Examples of refrigerants used include R1234yf, R134a, or similar.

[0015] The heat exchanger, also known as a heat transfer unit, thermally couples the refrigerant circuit to the coolant circuit. This coupling can be achieved by having the refrigerant and coolant flow through separate channels simultaneously within the heat exchanger. For example, the heat exchanger can include at least one channel for refrigerant flow, connected to the refrigerant circuit, and at least one channel for coolant flow, connected to the cooling circuit. The two channels can be in thermal contact with each other, for example, by being directly adjacent to one another, or they can be separated by a thermally conductive wall, such as one made of metal.

[0016] The control unit can be designed to detect the presence of the first operating mode. If the first operating mode is present, the control unit controls the cooling arrangement according to the first cooling mode. Control of the cooling arrangement according to the first cooling mode can therefore occur only if the first operating mode is present. Similarly, control of the cooling arrangement according to the second cooling mode can occur only if the second operating mode is present, and its presence can also be detected by the control unit.

[0017] The terms "first" and "second" refrigerant temperature refer to specific first and second values ​​of the refrigerant's temperature, respectively. Therefore, the terms "refrigerant temperature" and "refrigerant temperature value" are used synonymously, at least partially, in the following text, particularly in relation to the first and second refrigerant temperatures. Similarly, the first and second refrigerant temperatures will also sometimes be referred to as the first and second refrigerant temperature values.

[0018] When setting the second refrigerant temperature value, the refrigerant temperature can be reduced by several degrees Celsius compared to the first refrigerant temperature value, in particular by at least 5 °C, preferably by at least 10 °C, or more. This allows for particularly efficient battery cooling. The second refrigerant temperature can, for example, be set to a value of less than 10 °C, in particular less than 5 °C, and even less than 0 °C. When setting the second refrigerant temperature, it can even be lowered to an antifreeze temperature specific to the refrigerant, which is typically less than 0 °C. It is also conceivable that the control unit in the second cooling mode can set the refrigerant temperature to different values, for example, depending on the current battery temperature and / or the situation and / or the required cooling effect.All these temperature values ​​are then correspondingly lower than the first refrigerant temperature assigned to the first cooling mode.

[0019] The term "refrigerant temperature" refers specifically to the temperature of the refrigerant as it flows into and / or through the heat exchanger. The control unit can regulate the refrigerant temperature to the desired value, namely the first refrigerant temperature according to the first cooling mode and the second refrigerant temperature according to the second cooling mode. For this purpose, at least one temperature sensor can be provided in the refrigerant circuit, preferably near the heat exchanger, to measure the refrigerant temperature.

[0020] According to an advantageous embodiment of the invention, a chiller, particularly in the form of an evaporator designed as a plate heat exchanger, thermally couples the refrigerant circuit and the coolant circuit as the heat exchanger. In other words, a chiller, preferably in the form of an evaporator designed as a plate heat exchanger, can be used as the heat exchanger. The chiller can therefore also be referred to as an evaporator and / or plate heat exchanger. The chiller is thus a heat exchanger through which refrigerant flows on one side and coolant, for example, cooling water, flows on the other. This allows heat to be exchanged between the two circuits for cooling the battery in a particularly efficient manner.

[0021] According to a further advantageous embodiment of the invention, the control device for lowering the refrigerant temperature from the first refrigerant temperature to the second refrigerant temperature in the second cooling mode controls an expansion valve of the refrigerant circuit, which is arranged upstream of the heat exchanger with respect to a certain flow direction of the refrigerant circuit, in particular such that the refrigerant is expanded more strongly through the expansion valve in the second cooling mode than in the first cooling mode.

[0022] Because the expansion valve is positioned upstream of the heat exchanger with respect to the specific flow direction of the refrigerant circuit, the refrigerant flowing through the refrigeration circuit is expanded by the expansion valve before subsequently flowing through the heat exchanger. The expansion valve is therefore located upstream of the heat exchanger.

[0023] The expansion valve can also be called a throttle valve or throttle. By increasing the expansion of the refrigerant, i.e., by reducing the throttling, it can be cooled to lower temperatures. The control unit can regulate the expansion valve accordingly to cool the refrigerant to the secondary refrigerant temperature or to set the secondary refrigerant temperature. This allows for a simple reduction in the refrigerant temperature within the refrigeration circuit, particularly at the heat exchanger.

[0024] According to a further advantageous embodiment of the invention, the second operating mode represents a racing mode and / or a fast-charging mode for quickly charging the battery. This advantageously allows for particularly high performance, especially when driving on racetracks in racing mode, and / or enables a particularly high charging power, or the use of this high charging power for a particularly long time, when fast-charging the battery. However, other situations are also conceivable in which particularly rapid cooling of the battery is advantageous, for example, during passive cooling while the vehicle is stationary. Overall, in certain situations, for example, while driving, but also during charging or cooling while stationary, the battery can be cooled to a specific target temperature in a shorter time.

[0025] Furthermore, it may be possible for a vehicle user to manually activate the second cooling mode, for example, via a user interface. This would signal the presence of the second operating mode to the control unit, which would then switch to the second cooling mode. The second cooling mode could also be deactivated manually by a user. Alternatively, the presence of the second operating mode could not be signaled by a user, but rather detected by a vehicle detection device, such as the start of a charging or fast-charging process, high power demand, driving on a racetrack, or similar events.

[0026] The second cooling mode can be terminated if it is detected that the second operating mode is no longer present, and / or after a predetermined time period and / or when the predetermined target temperature of the battery is reached and / or under one or more optional further conditions, e.g., as described below.

[0027] According to a further advantageous embodiment of the invention, the control unit terminates or aborts the second cooling mode if it detects a predetermined, excessively high temperature difference between the measured cell temperatures of the battery cells. For detecting the cell temperatures, a suitable detection device, such as one or more temperature sensors, can be provided in the vehicle. This device allows the cell temperatures to be monitored repeatedly or continuously. If a predetermined, excessively high temperature difference occurs between two such cell temperatures, an excessively high temperature difference can be considered detected. This can be signaled to the control unit. The control unit can also evaluate the measured cell temperatures itself to detect such an excessively high temperature difference.An excessively high temperature spread can occur if the temperature difference between two battery cells exceeds a predetermined limit. In this case, the control unit can then terminate or cancel the second cooling mode. This prevents or at least limits a further increase in the temperature spread and avoids uneven or excessively uneven stress on the battery cells.

[0028] To end or cancel the second cooling mode, the control unit can, for example, switch back to the first cooling mode or to a different third cooling mode. In such a third cooling mode, a third refrigerant temperature in the refrigerant circuit can be set by the control unit, which is also lower than the first refrigerant temperature, but, for example, higher than the second refrigerant temperature. In other words, it is not necessary to abruptly discontinue increased cooling in such a case; it can also simply be reduced in intensity in a predetermined way by slightly raising the refrigerant temperature again, starting from the second refrigerant temperature value. The refrigerant temperature in the second and / or third cooling mode can also be regulated depending on such repeatedly detected temperature differentials.

[0029] According to a further advantageous embodiment of the invention, the control unit, for switching to the second cooling mode and / or during the second cooling mode, controls at least one pump of the coolant circuit to increase its pumping capacity. The increased pumping capacity then advantageously allows more coolant to be pumped through the coolant circuit per unit of time in the second cooling mode, or the volume flow rate to be increased. This, in turn, enables faster heat dissipation from the battery. This also results in faster cooling of the battery.

[0030] According to a further advantageous embodiment of the invention, the control unit for switching to the second cooling mode and / or in the second cooling mode controls a refrigerant compressor of the refrigeration circuit to increase the refrigerant flow rate through the refrigerant compressor, i.e., to increase the volume flow of the refrigerant through the refrigerant compressor. This also provides enhanced cooling and further promotes the cooling of the battery.

[0031] According to a further advantageous embodiment of the invention, the control unit for switching to the second cooling mode and / or during the second cooling mode controls a fan associated with the coolant circuit and / or a fan shroud of the fan to increase the airflow provided by the fan. The coolant circuit can therefore also include a fan, or the fan can be associated with the cooling circuit, more precisely with a (further) heat exchanger integrated into the cooling circuit. The fan can be located in the area of ​​the heat exchanger of the cooling circuit. This heat exchanger can, for example, be designed as a water cooler. The fan can thus be a radiator fan. By increasing the fan speed, a stronger airflow is provided for cooling such a heat exchanger.This allows the heat to be dissipated more quickly and efficiently by the heat exchanger, thus cooling the cooling circuit more effectively. The fan can also be equipped with a fan louver. In this case, the louver can preferably be opened or positioned as far as possible to maximize the airflow provided by the fan. This further enhances the cooling effect.

[0032] According to a further advantageous embodiment of the invention, the control unit for switching to the second cooling mode and / or in the second cooling mode controls at least one component associated with the coolant circuit for interior air conditioning, so that reduced interior air conditioning is provided. Components associated with interior air conditioning include, for example, an interior evaporator, an interior fan, and a valve associated with the interior circuit, wherein the interior cooling circuit can represent a sub-circuit of the coolant circuit, which can be connected in parallel to a battery cooling circuit as a further sub-circuit of the coolant circuit. For example, the flow rate per unit of time, i.e., the coolant flow through the interior evaporator, can be reduced or completely switched off, and / or the interior fan power can be reduced or the interior fan can be completely switched off.This allows the cooling demand at the interior evaporator to be reduced, thus strengthening the chiller. An energy reserve can therefore be created. This saves energy, and the saved cooling capacity benefits battery cooling via the battery cooling circuit.

[0033] Furthermore, the invention also relates to a control device for a motor vehicle, which is designed to execute a method according to the invention or one of its embodiments.

[0034] Furthermore, the invention also relates to a cooling system for a motor vehicle, which includes a control device according to the invention or one of its embodiments. The cooling system can also include the cooling arrangement as described in connection with the method according to the invention and / or its embodiments.

[0035] Furthermore, the invention also relates to a motor vehicle with a cooling system according to the invention or one of its embodiments. The motor vehicle may also include the battery.

[0036] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle. The motor vehicle can be designed as an electric vehicle.

[0037] The invention also includes further developments of the control device, the cooling system, and the motor vehicle according to the invention, which have features already described in connection with the further developments of the method according to the invention. For this reason, the corresponding further developments of the control device, the cooling system, and the motor vehicle according to the invention are not described again here.

[0038] The control device can include a data processing device or a processor device (processor circuit) configured to carry out an embodiment of the method according to the invention. For this purpose, the processor device can include at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (Field Programmable Gate Array) and / or at least one DSP (Digital Signal Processor). In particular, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an NPU (Neural Processing Unit) can be used as the microprocessor. Furthermore, the processor device can include program code configured to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device. The processor device can, for example,based on at least one circuit board and / or at least one SoC (System on Chip).

[0039] As a further solution, the invention also includes a computer-readable storage medium comprising program code which, when executed by a computer or a computer network, in particular the control unit, causes it to execute an embodiment of the method according to the invention. The storage medium can be provided at least partially as a non-volatile data storage medium (e.g., as flash memory and / or as an SSD - solid state drive) and / or at least partially as a volatile data storage medium (e.g., as RAM - random access memory). The storage medium can be located within the computer or computer network. However, the storage medium can also be operated, for example, as an app store server and / or cloud server on the internet. The computer or computer network can provide a processor circuit with, for example, at least one microprocessor.The program code can be provided as binary code, assembly code, source code of a programming language (e.g., C), or a program script (e.g., Python). Alternatively, the computer-readable storage medium can be implemented as a signal containing computer-readable data, such as a time-varying voltage signal or a radio signal.

[0040] The invention also includes combinations of the features of the described embodiments. The invention therefore also includes realizations that each exhibit a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

[0041] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 a schematic representation of a motor vehicle with a cooling arrangement according to an embodiment of the invention; and Fig. 2 a graphical representation of the mode of operation of the cooling arrangement in the first and second cooling modes according to an embodiment of the invention.

[0042] The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0043] In the figures, identical reference symbols denote functionally equivalent elements.

[0044] Fig. Figure 1 shows a schematic representation of a motor vehicle 10 according to an embodiment of the invention. The motor vehicle 10 comprises a cooling system 12 with a cooling arrangement 14 and a control unit 16 for controlling the cooling arrangement 14. The cooling arrangement 14 in turn comprises a cooling circuit 18 and a refrigerant circuit 20. The motor vehicle 10 also comprises a battery 22, for example, a high-voltage battery. This battery may comprise several battery cells, which are not explicitly shown here. The cooling circuit 18 comprises a cooling device 24, for example, a cooling plate 24 for cooling the battery 22. For this purpose, the cooling plate 24 may be arranged on the battery 22. The cooling plate 24 may comprise one or more cooling channels through which the coolant circulating in the cooling circuit 18 can flow. The cooling circuit 18 also includes a coolant pump 26 to circulate or pump the coolant in the cooling circuit 18.Furthermore, cooling circuit 18 includes a water cooler 28 and a radiator fan 30 associated with the water cooler. Cooling circuit 18 also includes a control valve 32 to integrate a heat exchanger in the form of a chiller 34, specifically an evaporator, into cooling circuit 18. The chiller 34 couples cooling circuit 18 with refrigeration circuit 20, at least when connected via valve 32 and / or valve 44 associated with refrigeration circuit 20. In this connected state, the chiller 34 is thus simultaneously supplied with coolant and refrigerant. The chiller 34 is therefore a heat exchanger through which refrigerant flows on one side and coolant, e.g., cooling water, on the other. Thus, heat is exchanged between the two circuits 18 and 20 to cool the battery 22. This allows heat to be transferred from the coolant to the refrigerant.The chiller 34 can therefore cool the cooling circuit 18 via the refrigerant circuit 20.

[0045] The refrigerant circuit 20 comprises a refrigerant compressor 36, a condenser 38 located downstream of the refrigerant compressor 36, a further evaporator 40 associated with the vehicle interior 42, and an interior fan 43. Upstream of the chiller 34, an expansion valve 44, as previously mentioned, is also located in the refrigerant circuit 20, and a further throttle valve 46 is also connected upstream of the interior evaporator 40. When the refrigerant circulates in the refrigerant circuit 20, it is compressed by the refrigerant compressor 36, particularly in its gaseous state, subsequently condensed by the condenser 38, expanded via the expansion valve 44, and fed to the chiller 34. Here, the refrigerant absorbs heat from the coolant circuit 18, thereby evaporating at least partially or completely, and is subsequently fed back to the refrigerant compressor 36, which compresses the refrigerant again.By reducing the flow rate using the expansion valve 44, the coolant cools down more significantly before being fed to the chiller 34 to absorb heat from the coolant circuit 18.

[0046] In conventional cooling systems, the chiller temperature is regulated to moderate temperatures, for example, from approximately 15 to 25 °C, to protect the battery cells from excessively high temperature differences combined with high heat flows. This results in very long cooling times, especially for batteries that are already warm, for example, over 90 minutes. Consequently, rapid cooling rates cannot be achieved.

[0047] The invention, or its embodiments, advantageously enables a significant improvement in the cooling times of the battery 22. This is achieved through a software function implemented by the control unit 16. This control unit can, for example, switch vehicle systems and / or thermal management systems in combination to achieve the shortest possible cooling time for the battery 22. This is particularly useful in certain operating situations B2 where the shortest possible cooling time for the battery 22 is desired. The presence of such an operating situation B2 can be signaled to the control unit 16. Normal operation B1 can also be signaled to the control unit 16. Depending on the operating mode B1 or B2, the control unit 16 controls the operation of one or more components of the cooling arrangement 14 differently.

[0048] In particular, when the first operating mode B1 is present, the control unit 16 controls the cooling arrangement 14 so that a first refrigerant temperature value T1 (cf. Fig. 2) on the chiller 34, which is set, for example, in the range of approximately 15 to 25 °C. If, on the other hand, the second operating mode B2 is present, the control unit 16 controls the cooling arrangement 14 in such a way that the refrigerant temperature is reduced, for example, to a specific second refrigerant temperature value T2 (see figure). Fig. 2) This can be achieved in a particularly effective way by, as already mentioned, a throttling device W in the refrigerant circuit 20 (see below). Fig. 2) This results in lower refrigerant pressures, which can be achieved by appropriately controlling the expansion valve 44. This allows, in particular, the refrigerant temperature at the chiller 34 to be set to approximately 5 °C or even -5 °C or lower, for example, down to the refrigerant's frost protection temperature. The second refrigerant temperature, T2, is therefore set by reducing the throttling W to values ​​below the standard values, such as those defined for the first operating mode, B1.

[0049] The lower the temperature of the refrigerant, which is achieved in particular by means of the described throttling W, the more heat can be extracted from the cooling circuit 18 in the cooling plate 24 and thus also from the battery 22. This allows the battery 22 to be cooled to a target temperature more quickly, both while driving and during charging or passive cooling while stationary. This improves vehicle conditioning for fast charging and for track use.

[0050] This approach can be further supported by additional or alternative measures. For example, the control unit 16 can also control the fan 30 to achieve constant cooling with a higher airflow. The fan 30 can be operated at a higher fan speed, for example, at maximum fan speed. Furthermore, the cooling louvers, which are not explicitly shown here for the sake of clarity and which may be located, for example, in front of the fan 30, can be permanently or fully opened during the second operating mode B2. Additionally or alternatively, the pump 26 can also be controlled to increase the volume flow through the coolant circuit 18 and thus provide a continuously adjusted volume flow during the second operating mode B2.Similarly, the refrigerant compressor 36 can also be controlled to adjust the refrigerant flow rate, in particular to increase it, e.g., again permanently during the second operating mode B2. Additionally or alternatively, the cooling demand at the interior evaporator 40 for the interior 42 can be reduced to enhance the chiller 34. Optionally, interior air conditioning can also be completely discontinued by closing the throttle valve 46. The interior fan 43 can also be operated at reduced power or switched off entirely, either additionally or alternatively. Thus, a corresponding cooling mode M2 ​​can be achieved in the second operating mode B2 (see...). Fig. 2) can be changed, in which very effective and rapid battery conditioning can be provided. Additionally, it is also conceivable that in this second operating mode B2 or in the associated second cooling mode M2, the battery 22 is supplied with cold water flowing over the cell cooling walls.

[0051] This second cooling mode M2 ​​can be maintained, for example, until a specific target temperature of battery 22 is reached and / or it is detected that the second operating mode B2 is no longer active and / or the first operating mode B1 is active again, and / or the second cooling mode is manually terminated, or similar. An additional monitoring function can also be provided to monitor the cell temperature spread of the battery cells in battery 22. If an excessive cell temperature spread is detected, the second cooling mode M1 can also be terminated or aborted.

[0052] Fig. Figure 2 shows a graphical representation of the operation of the cooling arrangement in the first and second cooling modes M1 and M2. The abscissa represents the enthalpy E of the refrigerant, in this example R1234yf, particularly on a linear scale, and the ordinate represents the refrigerant pressure p, particularly on a logarithmic scale. Region A1 represents the liquid region of the refrigerant, region A2 the biphase region in which the refrigerant exists simultaneously in both liquid and gaseous states, and A3 the gaseous region of the refrigerant. The temperature T in °C is also shown, both for the gaseous region A3 on the abscissa and on the boundary line between regions A1, A2, and A3. Arrows P1, P2, P3, P4, P5, and P6 illustrate the state transitions of the refrigerant caused by the individual components of the refrigeration circuit 20.

[0053] For example, the refrigerant is compressed by the compressor 36, as illustrated by arrow P1. The refrigerant is then condensed by the condenser 38, as illustrated by arrow P2. This occurs, for example, at 70 °C and 20 bar. The refrigerant then passes through the expansion valve 44 or throttling valve 44, which changes its volume. It is expanded or throttled. According to the first cooling mode M1, the throttling is greater, and the corresponding change of state is illustrated by arrow P3. This allows the first refrigerant temperature T1 to be reached. In the second cooling mode M2, the throttling is less pronounced, or rather, an unthrottled flow occurs; the corresponding change of state is illustrated by arrow P4. This allows the second refrigerant temperature T2 to be reached.As can be seen, by further reducing the throttling W by means of the expansion valve 44 to lower coolant pressures, a greater cooling of the refrigerant can be achieved.

[0054] In chiller 34, the refrigerant absorbs heat from cooling circuit 18. In the first cooling mode M1, this occurs, for example, at a refrigerant temperature of 15 °C and a refrigerant pressure p of 5.5 bar, as illustrated by arrow P5. In the second cooling mode M2, this occurs, for example, at a refrigerant temperature of 5 °C and a refrigerant pressure p of 4 bar, as illustrated by arrows P6.

[0055] Overall, the examples show how the invention can provide a battery conditioning function for racetrack use and fast charging. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 208 550 A1

[0004] WO 2022 / 090425 A1

[0005] DE 10 2022 210 733 A1

[0007]

Claims

[1] Method for controlling a cooling arrangement (14) for cooling a battery (22) of a motor vehicle (10) by means of a control device (16), - wherein the cooling arrangement (14) comprises a coolant circuit (18) through which a coolant flows, with a cooling device (24) for cooling the battery (22), and a refrigerant circuit (20) through which a refrigerant flows, and a heat exchanger (34) via which the refrigerant circuit (20) and the coolant circuit (18) are thermally coupled or can be coupled to each other for transferring heat from the coolant circuit (18) to the refrigerant circuit (20), - wherein the control device (16) in the presence of a first operating mode (B1) controls the cooling arrangement (14) according to a first cooling mode (M1) such that a first refrigerant temperature (T1) of the refrigerant is set at the heat exchanger (34), characterized by, that the control device (16) switches to a second cooling mode (M2) when a second operating mode (B2) is present, according to which the control device (16) controls the cooling arrangement (14) in such a way that at least temporarily a second refrigerant temperature (T2) of the refrigerant is set at the heat exchanger (34) which is lower than the first refrigerant temperature (T1). [2] Method according to claim 1, characterized by , that a chiller (34), in particular an evaporator designed as a plate heat exchanger, thermally couples the refrigerant circuit (20) and the coolant circuit (18) as the heat exchanger (34). [3] Method according to any one of the preceding claims, characterized by, that the control device (16) to reduce the refrigerant temperature from the first refrigerant temperature (T1) to the second refrigerant temperature (T2) in the second cooling mode (M2) controls an expansion valve (44) of the refrigerant circuit (20), which is arranged upstream of the heat exchanger (34) with respect to a certain flow direction of the refrigerant circuit (20), in particular so that the refrigerant is expanded more strongly through the expansion valve (44) in the second cooling mode (M2) than in the first cooling mode (M1). [4] Method according to any one of the preceding claims, characterized by , that the second operating mode (B1) represents a racing mode and / or fast charging mode for fast charging of the battery (22). [5] Method according to any one of the preceding claims, characterized by, that the control device (16) terminates or cancels the second cooling mode (M2) under the condition that the control device (16) detects a predetermined excessively high temperature spread of detected cell temperatures of battery cells of the battery (22). [6] Method according to any one of the preceding claims, characterized by , that the control unit (16) controls at least one pump (26) of the coolant circuit (18) to increase the pumping power in order to switch to the second cooling mode (M2) and / or in the second cooling mode (M2). [7] Method according to any one of the preceding claims, characterized by , that the control device (16) to switch to the second cooling mode (M2) and / or in the second cooling mode (M2) controls a refrigerant compressor (36) of the refrigerant circuit (20) to increase the refrigerant flow rate through the refrigerant compressor (36). [8] Method according to any one of the preceding claims, characterized by, that the control device (16) controls a fan (30) and / or a fan shutter of the coolant circuit (18) to increase an airflow provided by the fan (30) for switching to the second cooling mode (M2) and / or in the second cooling mode (M2). [9] Method according to any one of the preceding claims, characterized by , that the control unit (16) to switch to the second cooling mode (M2) and / or in the second cooling mode (M2) controls at least one component (46, 40, 43) assigned to the coolant circuit (18) for interior air conditioning, so that a reduced interior air conditioning performance is provided. [10] Control device (16) for a motor vehicle (10) designed to perform a method according to any of the preceding claims.

Images