Abstract:
A battery cooling device may include a refrigeration circuit configured to communicate a refrigerant in a flow direction. The refrigeration circuit may include a plurality of refrigerant paths configured to be flowed through in parallel by the refrigerant along the flow direction. The plurality of refrigerant paths may respectively include at least one of a cooling element and a cooling element section. The at least one of the cooling element and the cooling element section may be fluidically incorporated into the respective refrigerant paths and be thermally coupled in a heat-transmitting manner to at least one battery. A plurality of valve devices may be arranged in the respective refrigerant paths and be configured to control a throughflow of the refrigerant.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application No. 10 2014 206 770.7, filed Apr. 8, 2014, the contents of which are hereby incorporated by reference in their entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a battery cooling device, in particular for a vehicle with electric drive. The present invention also relates to a method for cooling batteries, in particular of a vehicle with electric drive. 
       BACKGROUND 
       [0003]    Vehicles with electric drive are for example purely electric vehicles, which have only an electric drive, or hybrid vehicles, which have a further drive in addition to an electric drive. In particular, this also includes vehicles which are equipped with a so-called “range extender”. In the case of vehicles of said type, batteries are used for storing electrical energy. The batteries can warm up when current is drawn and during charging. Elevated temperatures however have an adverse effect on the performance of the batteries. Accordingly, battery cooling devices are required in order to dissipate the heat that is generated at the batteries during the operation of the vehicle, for example in order to lengthen the service life of the batteries. If multiple batteries are used in a vehicle, it is also important that the batteries can as far as possible be operated at the same temperature level. 
         [0004]    US 2011/0 206 967 A1 has disclosed a vehicle with electric drive and with a battery cooling device, wherein the battery cooling device is equipped with a refrigeration circuit. As is conventional, the refrigeration circuit comprises, in a closed refrigerant path, a compressor for compressing a refrigerant which circulates in the refrigerant path. Downstream of the compressor there is arranged a condenser for the liquefaction of the compressed refrigerant. Downstream of the condenser there is provided an expansion device for expanding the liquefied refrigerant, with the refrigerant correspondingly cooling down at the same time. Furthermore, in the refrigerant path downstream of the expansion device, there are arranged cooling elements which are coupled in heat-transmitting fashion to batteries. The cooling elements serve, in the refrigeration circuit, as evaporators which evaporate the refrigerant. 
         [0005]    DE 10 2012 005 871 A1 has disclosed a plate-shaped cooling element in which there are provided multiple cooling ducts which can be flowed through in parallel by a coolant. 
         [0006]    EP 2 305 496 B1 has disclosed a further battery cooling device in which use is likewise made of a plate-shaped cooling element. 
       SUMMARY 
       [0007]    The present invention is concerned with the problem of specifying, for a battery cooling device and for an associated operating method, an improved embodiment which is distinguished in particular by the fact that, even in the case of a relatively large number of batteries, the longest possible service life of the batteries can be attained with the aid of the battery cooling device. 
         [0008]    Said problem is solved according to the invention by the subjects of the independent claims. The dependent claims relate to advantageous embodiments. 
         [0009]    The invention is based on the general concept of providing, in the refrigeration circuit, multiple refrigerant paths which can be flowed through in parallel by the refrigerant and in each of which there is arranged at least one cooling element or at least one cooling element section, in such a way that the respective cooling element or the respective cooling element section can be flowed through by the refrigerant. In the installed state of the battery cooling device, the cooling elements or the cooling element sections are coupled in heat-transmitting fashion to the batteries to be cooled. The invention furthermore proposes that the refrigerant paths and/or at least one refrigerant path group which comprises multiple refrigerant paths be controlled with regard to a throughflow of refrigerant by means of valve devices. In this case, the respective valve device is arranged in the respective refrigerant path downstream of a branching region, in which the refrigerant paths and/or the respective refrigerant path group branch(es) off from a refrigerant main line of the refrigeration circuit, and upstream of a confluence region, in which the refrigerant paths and/or the respective refrigerant path group are/is connected to the refrigerant main line again. By means of this design, it is possible for the individual refrigerant paths and/or the respective refrigerant path group to be controlled separately or in groups with regard to their throughflow of refrigerant in a particularly simple manner by means of the valve devices. In conjunction with corresponding temperature monitoring, it is thus possible in a particularly simple manner for flow to be conducted through the individual refrigerant paths and/or the respective refrigerant path group in a manner dependent on the respective cooling demand. The design proposed here thus makes it possible for the individual batteries to be protected against overheating, which lengthens the service life thereof. 
         [0010]    Specifically in the case of automotive applications, it is often the case that multiple batteries are combined to form a battery block, wherein the individual batteries within a battery block of said type can also be referred to as battery cells. The cooling elements proposed here may then be assigned to a battery block of said type or else to individual batteries or battery cells. 
         [0011]    In a particularly advantageous embodiment, no refrigerant path groups are provided, such that all of the refrigerant paths can be controlled individually by means of separate valve devices. 
         [0012]    In a simplified embodiment, it is likewise possible for all refrigerant paths to each be assigned a separate valve device, wherein grouping of the refrigerant paths into individually controlled groups is nevertheless possible, for example in order to keep the cooling power as constantly as possible at a high level. In this case, the refrigerant paths of a refrigerant path group of said type are each individually controllable with regard to their throughflow of refrigerant by means of a separate valve device. For example, nine refrigerant paths numbered continuously from 1 to 9 may be provided, which altogether may be divided into three refrigerant path groups. A first refrigerant path group may for example comprise refrigerant paths numbers 1 to 3. A second refrigerant path group may for example comprise refrigerant paths numbers 4 to 6. A third refrigerant path group may for example comprise refrigerant paths numbers 7 to 9. It is thus possible, by synchronized actuation of the associated valve devices, for flow to be conducted through the refrigerant paths of the three refrigerant path groups in succession. 
         [0013]    It may alternatively be provided that the refrigerant paths of a refrigerant path group of said type are controllable in groups with regard to their throughflow of refrigerant by means of a common valve device. In the above example, the three refrigerant paths of the respective refrigerant path group are then in each case assigned a common valve device. 
         [0014]    In a further alternative, the refrigerant paths of a refrigerant path group of said type may be individually controllable with regard to their throughflow of refrigerant by means of a common valve device. What is conceivable, for example, is a valve device by means of which two or more refrigerant paths can be selectively connected to a common port (inlet or outlet) of the refrigerant path group. In particular, it may be provided that it is always the case that at least one of the refrigerant paths of the refrigerant path group is connected to the common port, while all the other refrigerant paths of said refrigerant path group are then blocked. Accordingly, it is always the case that flow passes through at least one of the refrigerant paths of said refrigerant path group, wherein the respective refrigerant path through which flow passes can be selected by means of the valve device. 
         [0015]    In another advantageous embodiment, the respective valve device may be designed as an open-closed valve which can be switched only between an open position and a closed position. Such valve devices can be produced at particularly low cost and exhibit high reliability. For example, an open-closed valve of said type may be in the form of a solenoid valve, the valve element of which is electromagnetically adjustable. A solenoid valve of said type can assume one switching position, for example the closed position, in the de-energized state and can assume the other switching position, for example the open position, in the energized state. With corresponding configuration of the refrigeration circuit, it is thus also possible to realize a failsafe principle, such that the risk of damage to the battery cooling device in the event of an electrical failure is reduced. 
         [0016]    In a particularly advantageous embodiment, a control device for actuating the valve devices may be provided, which control device is coupled to the valve devices in a suitable manner, for example by way of electrical lines, and is configured and/or programmed such that, during the operation of the battery cooling device, said control device actuates the valve devices such that the individual refrigerant paths are flowed through temporally in succession by the entire refrigerant flow flowing in the refrigerant main line. This measure ensures that it is always the case that a defined refrigerant flow, that is to say in particular a known volume flow, flows through the individual refrigerant paths. By means of these known parameters, the cooling power of the respective cooling path can be determined with relatively high accuracy. Furthermore, by means of this measure, a so-called “oil trap” within the refrigeration circuit can be eliminated. For lubrication of the compressor that is normally incorporated into the refrigeration circuit, the refrigerant comprises a certain lubricant fraction, wherein the lubricant is generally an oil. Whereas the refrigerant evaporates and condenses within the refrigeration circuit in accordance with the cycle, the lubricant generally remains in liquid form, and can accumulate in a geodetically low-lying refrigerant path. Owing to the fact that all of the refrigerant paths are flowed through in succession by the entire refrigerant flow, all of the refrigerant paths are forcibly scavenged, whereby all accumulations of lubricant can be discharged. 
         [0017]    In one advantageous refinement, the control device may be configured and/or programmed such that, during the operation of the battery cooling device, said control device successively actuates in each case only one of the valve devices to open while simultaneously actuating all of the other valve devices to close. A corresponding situation applies in the case of grouping of the refrigerant paths, such that then only the valve device(s) assigned to the respective refrigerant path group are actuated to open, whereas all of the other valve devices are adjusted into the closed position. In this way, it is achieved in a particularly simple manner that the entire refrigerant flow, which also flows in the refrigerant main line, flows through the respective individual open refrigerant path or through the respective refrigerant path group. Thus, the entire cooling power of the refrigeration circuit is available to the respective refrigerant path or to the respective refrigerant path group. 
         [0018]    In another refinement, a temperature sensor arrangement may be provided for detecting the temperatures of the batteries assigned to the individual refrigerant paths or refrigerant path groups, which temperature sensor arrangement is coupled to the control device in a suitable manner, for example by way of corresponding electrical lines. The control device may in this case be configured and/or programmed such that, in a manner dependent on the determined temperatures, said control device selects opening times of the valve devices such that the valve device of the respective refrigerant path is actuated to open for longer the higher the temperature of at least one battery assigned to said refrigerant path and/or to said refrigerant path group is, or the higher the average temperature of all of the batteries of said refrigerant path and/or of said refrigerant path group is. In other words, the greater the cooling demand in the respective refrigerant path or in the respective refrigerant path group, the longer said refrigerant path or said refrigerant path group is flowed through by the entire refrigerant flow. In this way, it is possible to achieve cooling of the individual batteries, or of the batteries assigned to the individual refrigerant paths or to the respective refrigerant path group, in accordance with demand. 
         [0019]    In one advantageous refinement, the controller may be configured and/or programmed such that, for each refrigerant path and/or for each refrigerant path group, said controller performs separate temperature regulation through variation of the opening times of the associated valve devices. It is thus possible for all of the refrigerant paths and/or refrigerant path groups to be flowed through by refrigerant in accordance with demand in order to regulate the temperatures of the associated batteries. What is preferable here is on-off control, which can be realized in a particularly simple manner. For example, an upper threshold temperature ensures that the opening time of the respective valve device is increased to a certain extent, whereas a lower threshold temperature ensures that the opening time of the respective valve device is reduced again to a particular extent. For example, to increase the cooling action, the opening time may be doubled in relation to normal operation. More complex temperature regulation is likewise also conceivable. For example, various temperatures may be stored in a characteristic map, which temperatures are assigned suitable opening times for the respective valve device. The assignments may in this case vary from refrigerant path to refrigerant path or from refrigerant path group to refrigerant path group in order to allow for the respective boundary conditions of the individual refrigerant paths or refrigerant path groups. For example, the different refrigerant paths or refrigerant path groups may be of different lengths and/or may be assigned a different number of batteries and/or may comprise a different number of refrigerant paths. 
         [0020]    In one advantageous embodiment, at least one refrigerant path may comprise multiple cooling elements which can be flowed through in series by the refrigerant or multiple cooling element sections which can be flowed through in series by the refrigerant. The heat transfer capacity or the cooling capacity of the individual refrigerant path can be correspondingly increased in this way. 
         [0021]    A refinement is advantageous in which at least one refrigerant path comprises a single cooling element which comprises multiple refrigerant sections which can be flowed through in series by the refrigerant. In this way, within a single cooling element, multiple cooling element sections are provided which are flowed through in succession by the refrigerant. 
         [0022]    In another embodiment, multiple or all cooling elements assigned to separate refrigerant paths may define a cooling element group which has at least one separate cooling element for each associated refrigerant path. In this case, the individual refrigerant paths are assigned complete cooling elements rather than cooling element sections. 
         [0023]    In another advantageous embodiment, the respective valve devices may be arranged in the respective refrigerant path and/or in the respective refrigerant path group upstream of that cooling element or cooling element section which is flowed through by the refrigerant first or downstream of that cooling element or cooling element section which is flowed through by the refrigerant last. The construction of the individual refrigerant paths and/or of the respective refrigerant path groups is simplified in this way, as the associated valve device need merely be positioned upstream or downstream of the associated cooling elements and/or cooling element sections. 
         [0024]    An embodiment is preferable in which each refrigerant path which does not belong to a refrigerant path group is assigned a separate valve device. In this way, it is possible in particular to realize two or more parallel refrigerant paths which can be flowed through independently of one another, in particular in succession, by refrigerant. 
         [0025]    Alternatively or in addition, it may be provided in another embodiment that a refrigerant path group of said type is assigned precisely two refrigerant paths, wherein the refrigerant paths are then assigned a common valve device, specifically such that the respective valve device, in a first switching position, blocks the first refrigerant path of this refrigerant path group and opens the second refrigerant path of this refrigerant path group and, in a second switching position, opens the first refrigerant path and blocks the second refrigerant path. Thus, the respective valve device is assigned two refrigerant paths, whereby this embodiment can be realized at particularly low cost. In particular, the refrigeration circuit in this embodiment comprises only two refrigerant paths in total. 
         [0026]    The method according to the invention for cooling batteries utilizes a refrigeration circuit which has cooling elements or cooling element sections coupled in heat-transmitting fashion to the batteries, wherein the cooling elements or cooling element sections are arranged so as to be distributed across multiple refrigerant paths which can be flowed through in parallel by the refrigerant. The method according to the invention is characterized in that multiple or all separate refrigerant paths are controlled individually with regard to their throughflow of the refrigerant. It is thus possible for the individual refrigerant paths to be flowed through by refrigerant in accordance with their present cooling demand, which optimizes the cooling of the respectively associated batteries and lengthens the service life thereof. 
         [0027]    In particular, the method is carried out such that the individual control of the refrigerant paths with regard to their throughflow of refrigerant ultimately leads to a homogenous temperature distribution within the batteries assigned to the individual refrigerant paths. 
         [0028]    In one advantageous embodiment, all separate refrigerant paths can be individually controlled with regard to their throughflow of refrigerant. Alternatively, at least two refrigerant paths may belong to a refrigerant path group, wherein the respective refrigerant path group is controlled individually with regard to its throughflow of refrigerant. The refrigerant paths associated with the refrigerant path group are in this case controlled in grouped fashion with regard to their throughflow of refrigerant. 
         [0029]    In another advantageous refinement of the method, the separate refrigerant paths can be flowed through temporally in succession by the entire refrigerant flow flowing in the refrigeration circuit. Thus, the entire cooling power of the refrigeration circuit is temporarily available in full to each individual refrigerant path. 
         [0030]    In another advantageous refinement, a time period during which the individual refrigerant paths are flowed through by the entire refrigerant flow can be selected individually for the individual refrigerant paths in a manner dependent on the present cooling demand of the respective refrigerant path. It is thus possible to realize flow through the individual refrigerant paths in accordance with demand. 
         [0031]    Further important features and advantages of the invention will emerge from the subclaims, from the drawings and from the associated description of figures on the basis of the drawings. 
         [0032]    It is self-evident that the features mentioned above and the features yet to be discussed below may be used not only in the respectively specified combination but also in other combinations or individually without departing from the scope of the present invention. 
         [0033]    Preferred exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description, wherein identical or similar or functionally identical components are denoted by the same reference signs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    In the figures, schematically in each case: 
           [0035]      FIG. 1  is a greatly simplified diagrammatic illustration, in the form of a circuit diagram, of a battery cooling device with a cooling element arrangement arranged in a refrigeration circuit, 
           [0036]      FIGS. 2-4  are greatly simplified diagrammatic illustrations of cooling element arrangements in different embodiments, 
           [0037]      FIG. 5A  is a greatly simplified diagrammatic illustration of a cooling element with integrated valve device in a first switching position according to an example, and 
           [0038]      FIG. 5B  illustrates a simplified diagrammatic illustration of the cooling element according to  FIG. 5A  with integrated valve device in a second switching position according to an example. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    In accordance with  FIG. 1 , a battery cooling device  1 , which is preferably used in a vehicle with electric drive (not shown here), comprises a refrigeration circuit  2  which has a refrigerant main line  3 , into which there is incorporated a cooling element arrangement  4  which, in  FIG. 1 , is enclosed by a border with dashed lines. As is conventional, the refrigeration circuit  2  comprises, in its refrigerant main line  3 , a compressor  5  for compressing the gaseous refrigerant which circulates in the closed refrigeration circuit  2 . Downstream of the compressor  5  there is provided a condenser  6  which is connected to a cooling circuit  7  and which extracts heat from the vaporous, compressed refrigerant, such that said refrigerant condenses. Arranged downstream of the condenser  6  there is an expansion device  8 , which in this case forms part of the cooling element arrangement  4  and which is generally an expansion valve. The expansion device  8  is required firstly in order that the compressor  5  can generate the required pressure in the refrigerant. Secondly, the expansion device  8  effects an expansion of the cooled, pressurized and liquid refrigerant. The pressure reduction is associated with a temperature reduction, such that expanded, cooled and liquid refrigerant is present downstream of the expansion device  8 . 
         [0040]    As per  FIG. 1 , it is optionally possible for the refrigeration circuit  2  to be assigned, in parallel with the cooling element arrangement  4 , a front-end evaporator  23  and/or a rear-end evaporator  24 . The front-end evaporator  23  may be assigned to a front-end air-conditioning device of the respective vehicle, whereas the rear-end evaporator  24  may be assigned to a rear-end air-conditioning device of the respective vehicle. In the example of  FIG. 1 , the respective additional evaporator  23 ,  24  is in each case assigned a separate expansion valve  25  and  26  respectively. 
         [0041]    Within the cooling element arrangement  4 , the refrigeration circuit  2  furthermore comprises multiple refrigerant paths  9 , which can be flowed through in parallel by the refrigerant. For this purpose, the refrigerant paths  9  branch off from the refrigerant main line  3  in a branching region  10 . The refrigerant paths  9  are led back into the refrigerant main line  3  again in a confluence region  11 . In the respective refrigerant path  9  there is arranged at least one cooling element  12  which can be flowed through by the refrigerant. In the example of  FIG. 1 , each refrigerant path  9  comprises precisely one cooling element  12 , this however being merely an exemplary embodiment for simplifying the illustration. Furthermore,  FIG. 1  shows precisely four refrigerant paths  9 , again merely by way of example. Any other desired number is basically also conceivable here. 
         [0042]    Corresponding to  FIG. 1 , the cooling elements  12  are each coupled in heat-transmitting fashion to at least one battery  13 , such that heat generated in the batteries  13  can be absorbed by the cooling elements  12  and can be dissipated in the respective refrigerant path  9 . 
         [0043]    By way of example,  FIGS. 2-4  show the possibility of providing a total of m refrigerant paths  9 , wherein m is an integer ≧2. Comprised within the respective refrigerant path  9  there are n cooling elements  12 , wherein n is an integer ≧2. It is basically also possible for only a single cooling element  12  to be contained within the respective refrigerant path  9 . Furthermore, it is clear that a different number of cooling elements  12  may also be comprised within the individual refrigerant paths  9 . Furthermore, it is also the case that the cooling elements  12  need not be of identical construction, although structurally identical cooling elements  12  are advantageous with regard to inexpensive manufacture.  FIGS. 2-4  thus show, for the cooling elements  12 , a matrix which has 1 to n columns and 1 to m rows. 
         [0044]    The refrigerant paths  9  can be controlled with regard to their capacity for a throughflow of refrigerant. For this purpose, in  FIGS. 1-4 , each refrigerant path  9  is equipped with a valve device  14 . In  FIGS. 2-4 , the respective valve device  14  is furthermore denoted by V.  FIG. 1  also shows a control device  15  which is coupled to the valve devices  14  in a suitable manner. Corresponding control lines  16  are indicated by way of example. Furthermore, in  FIG. 1 , a temperature sensor arrangement  17  is provided which, in the example, comprises multiple temperature sensors  18  which are assigned to in each case one of the batteries  13  in order to detect the temperature thereof. The temperature sensor arrangement  17  or the individual temperature sensors  18  are coupled to the control device  15  in a suitable manner, for example by way of signal lines  19  which are indicated here. The control device  15  can thus realize temperature regulation of the individual refrigerant paths  9 . For this purpose, the control device  15  can for example select the opening times of the valve devices  14  in a manner dependent on the determined temperatures. Higher temperatures signal a higher cooling demand in the respective refrigerant path  9 . Accordingly, a higher temperature leads to a longer opening time at the associated valve device  14 . 
         [0045]    The control device  15  is configured so as to actuate the valve devices  14  such that the individual refrigerant paths  9  are in each case flowed through temporally in succession by the entire refrigerant flow flowing in the refrigerant main line  3 . For this purpose, the control device  15  can successively actuate in each case only one of the valve devices  14  for opening, while simultaneously actuating all of the other valve devices  14  to close. After the predetermined opening time of the respective open valve device  14 , said valve device is actuated to close, while at the same time the next valve device  14  is actuated to open. 
         [0046]    As can be seen from  FIGS. 2-4 , the refrigerant paths  9  shown here each comprise multiple cooling elements  12  which are flowed through in series by the refrigerant. In the embodiments of  FIGS. 2-4 , the cooling elements  12  assigned to the separate refrigerant paths  9  define a cooling element group  20 . The respective cooling element group  20  has at least one separate cooling element  12  for each associated refrigerant path  9 . 
         [0047]    In the embodiment shown in  FIG. 2 , the respective valve device  14  is arranged in the associated refrigerant path  9  upstream of the cooling element  12  through which flow passes first. Furthermore, the respective valve device  14  is situated downstream of the branching region  10 . Furthermore, in this example, the expansion device  8  is arranged upstream of the branching region  10 , that is to say in the refrigerant main line  3 . 
         [0048]    In the embodiment shown in  FIG. 3 , the valve devices  14  are arranged within the respective refrigerant path  9  downstream of the cooling element  12  through which flow passes last. Furthermore, the valve devices  14  are arranged upstream of the confluence region  11 . The expansion device  8  is again arranged upstream of the branching region  10 . 
         [0049]      FIG. 4  then shows an embodiment in which, by contrast to  FIGS. 1-3 , a common expansion device  8  arranged in the refrigerant main line  3  is not provided, this being replaced by multiple separate expansion devices  8  which are each arranged in one of the refrigerant paths  9 . In the example of  FIG. 4 , the expansion devices  8  are each situated in the respective refrigerant path  9  upstream of the cooling element  12  through which flow passes first, and merely by way of example, downstream of the associated valve device  14 . It is also conceivable here for the valve devices  14  to be arranged downstream of the expansion devices  8 , in particular downstream of the cooling element  12  through which flow passes last. 
         [0050]    The cooling elements  12  within the respective refrigerant path  9  serve, within the refrigeration circuit  2 , as evaporators or pre-evaporators for the refrigerant. During the evaporation of the refrigerant, the cooling elements  12  absorb a large amount of heat. 
         [0051]    Whereas the embodiments shown in  FIGS. 1-4  are based on separate valve devices  14  being arranged in the individual refrigerant paths  9 ,  FIGS. 5   a  and  5   b  show an embodiment in which two refrigerant paths  9  are combined to form a refrigerant path group  27 , wherein said refrigerant path group  27  is assigned only one valve device  14 . Accordingly, in this case, precisely two refrigerant paths  9  are assigned a common valve device  14 . One refrigerant path, or the first refrigerant path, is in this case denoted by  9 ′, whereas the other refrigerant path, or the second refrigerant path, is denoted by  9 ″. In  FIGS. 5   a  and  5   b , a valve element  28  of the valve device  14  is designed, by way of example, as a slide. The valve device  14  can, in a first switching position as per  FIG. 5   a , block the first refrigerant path  9 ′ and open the second refrigerant path  9 ″, such that in this case flow passes only through the second refrigerant path  9 ″. As per  FIG. 5   b , the valve device  14  can then, in a second switching position, open the first refrigerant path  9 ′ and block the second refrigerant path  9 ″. As a result, all of the refrigerant flows only through the first refrigerant path  9 ′. 
         [0052]    The battery cooling device  1  presented in  FIGS. 1 to 5  can in particular be operated such that multiple or all separate refrigerant paths  9  and/or refrigerant path groups  27  are controlled individually with regard to their throughflow of refrigerant. This mode of operation, or an operating method of said type, can be realized through corresponding programming of the control unit  15 . In particular, the individually controllable refrigerant paths  9  can be controlled in targeted fashion such that a homogenous temperature distribution is realized in the associated batteries  13 . What is preferable is a mode of operation in which the separate refrigerant paths  9  and/or the refrigerant path groups  27  that may be provided are flowed through temporally in succession by the entire refrigerant flow flowing in the refrigeration circuit  2 . For this purpose, the valve devices  14  are actuated to open in succession, such that, preferably, it is always the case that only one valve device  14  is open, whereas all of the other valve devices  14  are closed. Since these states are always present only temporarily, such that all of the refrigerant paths  9  are flowed through in succession, the individual valve devices  14  are actuated in cyclic fashion over time by the control device  15 , such that this can also be referred to overall as cyclic operation. Suitable cycle frequencies or switching frequencies may in this case lie in a range from 0.001 Hz to 100 Hz. It is for example possible for the respective refrigerant path  9  and/or the refrigerant paths  9  combined to form a group  27  to each be flowed through by the refrigerant flow for approximately 1 s and then blocked again until the next cycle. If the batteries  13  assigned to the different refrigerant paths  9  generate different temperatures, it is also possible for the individual refrigerant paths  9  and/or refrigerant path groups  27  to be individually flowed through by refrigerant in accordance with the respectively present cooling demand. It is preferably the case here that a time period during which the individual refrigerant paths  9  are flowed through by the entire refrigerant flow is selected individually for the individual refrigerant paths  9  in a manner dependent on the present cooling demand of the respective refrigerant path  9 . In particular, it is possible in this way to realize individual temperature regulation of the individual refrigerant paths  9 . 
         [0053]    It is clear that separately controllable refrigerant paths  9  may also be implemented in combination with at least one refrigerant path group  27 . The respective refrigerant path group  27  is then treated as a separate refrigerant path  9  by the respective controller.