Abstract:
The invention relates to a device ( 710, 720, 730, 740 ) for monitoring an energy store ( 20; 30 ) comprising a plurality of battery cells ( 500   1111 -500 klmn ), which are arranged in a plurality of battery groups ( 200   1 - 200   k   , 300   11 - 300   kl   , 400   111 - 400   klm ), and a temperature-control device for controlling the temperature of the battery cells ( 500   1111 - 500   klmn ) by means of a plurality of partial flows of a temperature-control medium, each of the partial flows being associated with one of the battery groups ( 200   1 - 200   k   , 300   11 - 300   kl   , 400   111 - 400   klmn ), characterized by: a plurality of sensor apparatuses ( 720 ) for sensing temperature measurement values of the battery cells (500 1111 -500 klmn ), each of the sensor apparatuses ( 720 ) being arranged in such a way that the sensor apparatus can sense the temperature measurement value of one of the battery cells ( 500   1111 - 500   klmn ); an apparatus ( 710, 740 ) for determining a plurality of average temperature values from the sensed temperature measurement values, each of the determined average temperature values being determined in such a way that the determined average temperature value is associated with one of the battery groups ( 200   1 - 200   k   , 300   11 - 300   kl   , 400   111-   400   klmn ); and an apparatus ( 740 ) for evaluating the plurality of determined average temperature values and, if one of the determined average temperature values exceeds a temperature threshold value, determining that the partial flow associated with the associated battery group ( 200   1 - 200   k   , 300   11 - 300   kl   , 400   111 - 400   klm ) has a fault. The invention further relates to a battery system, a vehicle, a method, a computer program, and a computer program product.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a device and method for monitoring an energy store or respectively battery system as well as to an energy store having the device. The invention further relates to a vehicle, in particular a motor vehicle such as an electric vehicle or hybrid vehicle having the energy store. 
         [0002]    It is foreseeable that new battery systems, for example comprising lithium-ion batteries or nickel-metal hydride batteries, will increasingly be used in stationary applications, for example in wind turbines, in industry or in domestic engineering as well as in mobile applications, for example in electric vehicles (EV) or hybrid vehicles (hybrid electric vehicles HEV) as rechargeable energy stores. 
         [0003]    The battery systems have to meet very high requirements with regard to available energy content, charging and discharging efficiency, reliability, service life and with regard to undesirable loss of capacity due to frequent partial discharge. 
         [0004]    A battery system or respectively an energy store comprises a plurality of battery cells. The battery cells heat up during charging and discharging due to their cell internal resistance and the electrochemical processes taking place. The battery cells can be connected in series in order to increase the electrical voltage and/or in parallel in order to increase the maximum electrical current. In so doing, the battery cells can be consolidated into battery units or battery modules. The battery module holds the battery cells and absorbs mechanical stresses so that the battery cells are protected from being damaged. The battery module can furthermore provide a mechanical bracing of the battery cells and an electric insulation. In addition, the battery module can be used for the temperature control of the battery cells. 
         [0005]      FIG. 1  shows a schematic view of an energy store  10  according to the prior art, which, for example, can be used for a stationary application. The energy store or respectively the battery system  10  comprises a plurality of battery cells  500   1111  to  500   klmn . The plurality of battery cells  500   1111  to  500   klmn  is arranged in a plurality of battery modules  400   111  to  400   klm , so that each battery cell comprises n battery cells. The plurality of battery modules  400   111  to  400   klm  is arranged in a plurality of battery strings  300   11  to  300   kl , so that each battery string comprises m battery modules. The plurality of battery strings  300   11  to  300   kl  is arranged in a plurality of partial batteries  200   1  to  200   k , so that each partial battery I comprises battery strings. The plurality of partial batteries  200   1  to  200   k  is arranged as a battery  100 , so that the battery k comprises partial batteries. The battery  100  comprises lines  110   1 ,  110   2  for connecting the partial batteries  200   1  to  200   k , so that the electrical energy is available at the connections  120   1 ,  120   2 . 
         [0006]    The temperature range for the operation of the battery cells lies typically between 0° C. and +40° C., preferably between +25° C. and +35° C. The performance of the battery cells can drop significantly in the lower range of the operating temperature. The internal resistance of the battery cells increases considerably at temperatures under approximately 0° C., and the performance and the degree of efficiency of the battery cells drop continuously when temperatures continue to fall. As a result, irreversible damage to the battery cells can also occur. If the operating temperature is exceeded, the performance of the battery cells can also drop significantly. The service life of the battery cells is reduced at temperatures above approximately 40° C. As a result, irreversible damage to the battery cells can likewise occur. Furthermore, the temperature difference (temperature gradient), which is admissible for the operation of the battery cells, in a battery cell and/or within a battery module or a battery typically lies between 5 Kelvin and 10 Kelvin. In the case of larger temperature gradients, different regions of a battery cell or different battery cells of a battery module or a battery can experience different stresses or even be (partially) overloaded and/or damaged. In addition, a danger of condensation forming in the battery exists due to temperature gradients and/or temperature changes. The damage can lead to an accelerated ageing of the battery cells or to a thermal runaway of the battery cells, which presents a danger for humans and the environment. 
         [0007]    A battery system in which, for example, approximately 100 battery cells are wired in series or respectively parallel, can be used as a traction battery for driving vehicles. In the case of a high-voltage battery system, the total voltage can thus, for example, be 450 V or 600 V. 
         [0008]    In a hybrid drive train of a vehicle, lithium-ion high performance battery cells having very high dynamics are operated. During short-term peak loads, which, for example, arise as a result of recuperation of brake energy during braking or boost support when accelerating, the battery cells have to consume a large amount of power (during charging) or deliver a large amount of power (during discharge) in a very short amount of time. These short peak loads cause the battery cells to heat up significantly due to the internal resistance of the battery cells. The degree of efficiency of the battery cells during charging or discharging is very high (approximately 95%). Nevertheless, the resulting waste heat is not insignificant. A loss of 5% results in a power loss of 3 KW for a traction output of, for example, 60 KW. In addition, outside temperatures which amount to 40° C. and more can, for example during the summer months or in warmer regions, lie outside of the admissible temperature range, so that the battery cells cannot reach a service life of, for example, ten years. 
         [0009]    In order to ensure the dependability, function and service life of the battery module or respectively battery system, it is therefore necessary to operate the battery cells within the predefined temperature range. On the one hand, heat arises, as described above, during the operation of the battery cells, which has to be removed, in order to prevent the battery cells from heating up above the critical maximum temperature. On the other hand, it may be necessary to heat up the battery cells to a minimum temperature in the case of very low temperatures. In order to adhere to the predefined temperature range, the battery module or respectively battery system is temperature-controlled, i.e cooled or heated according to need. 
         [0010]    To this end, the battery module or respectively battery system can comprise a fluid, for example a liquid such as alcohol, for example, propane-1,2,3-triol (glycerol, glycerin), oil or water, for example, salt water or a liquid mixture, as a temperature-control medium, for example coolant in a temperature-control medium circuit. 
         [0011]    The cooling of the battery cells can, for example, be achieved by cooling plates, on which the battery cells are mounted. In the cooling plates, either a cooling agent such as coolant (air-heat radiator) or a refrigerant, which evaporates due to the heat (evaporator), absorbs the heat of the battery cells and discharges said heat via a radiator to the surrounding environment or to an air conditioning system (AC). Besides the cooling plates or the evaporator and the radiator, a cooling system further comprises tubes and/or pipes, for example made from plastic or metal such as aluminum, for connecting the cooling plates, the evaporator and/or the radiator. The cooling system can furthermore comprise a device for shutting off and/or controlling the flow of the temperature-control medium, for example a shut-off device such as a shut-off cock, a shut-off valve or a shut-off slide, or a valve like a manually actuated valve, an electromotively actuated valve or an electromagnetically actuated valve. The cooling system can furthermore comprise a flow sensor, for example an oval wheel meter, roller or piston type flow meter, impeller flow meter, magnetically inductive flow sensor, inductive flow sensor, ultrasonic flow sensor or Coriolis mass flow sensor, for detecting defects or faults of the cooling system, such as blockages, defects or faults of the shut-off device or respectively control device, or leakages which lead to an interruption of the temperature-control medium flow. 
         [0012]    The European Patent Office application EP 1 309 029 A2 discloses a method and a device for controlling the cooling and detection of abnormalities in a battery pack system which comprises a plurality of battery pack blocks, which are connected to one another in series, in parallel or via a combination consisting of a series circuit and a parallel circuit, wherein each of the battery pack blocks is formed by connecting a plurality of cells in series, and each battery pack block contains a cooling unit for providing an air flow in the associated battery pack block, and a cooling mode of a battery pack block is changed if a difference in the state of charge between the battery pack block and another battery pack block exceeds a threshold value. 
         [0013]    In order to increase the fail-safe stability, reliability and the disposability of battery systems and to reduce the costs of said battery systems, it is therefore necessary to improve the monitoring of the temperature-control system. 
       SUMMARY OF THE INVENTION 
       [0014]    The inventive devices and methods have the advantage that the temperature-control medium flow monitors the cooling system, and faults or defects in said cooling system, such as blockages, component defects or leakages can be detected and signaled. As a result, the susceptibility to failure, reliability and disposability of energy stores or respectively battery systems can be improved. In addition, flow sensors can be eliminated. As a result, the design of the battery system can be simplified and the number of components of the battery system can be reduced. Hence, the susceptibility to failure can be further lowered. Furthermore, the costs, for example manufacturing costs, service costs or maintenance costs can be reduced and resources can be saved. 
         [0015]    In an advantageous manner, the temperature threshold value can correspond to a predetermined maximum temperature value. In so doing, a maximum admissible operating temperature of the energy store can be maintained. Thus, the dependability and the service life of the battery cells can be increased. 
         [0016]    In an expedient manner, the temperature threshold value can be determined or codetermined by means of an average temperature value from the plurality of average temperature values. The battery cells of the energy store can thereby be compared with one another while taking into account the age thereof and the current load thereon. A provision and storage of predetermined reference values can furthermore be eliminated. 
         [0017]    In an expedient manner, the apparatus for determining can be designed as a decentralized pre-processing apparatus. As a result, the transmission of values and the stress on the central processing apparatus can be reduced. In addition, the number of connection lines can be reduced. 
         [0018]    In an expedient manner, the apparatus for determining and/or the apparatus for evaluating and determining can be designed as a central processing apparatus. As a result, the complexity of the monitoring device can be reduced. In addition, the flexibility and maintainability of the monitoring device can be increased. 
         [0019]    In an expedient manner, the battery groups can be designed as partial batteries, battery strings or battery modules. In so doing, the monitoring device can be adapted to the design of the energy store. 
         [0020]    The invention provides a battery system which comprises the previously described device. 
         [0021]    The invention further provides a vehicle, in particular a motor vehicle such as an electric vehicle, hybrid vehicle or electric motor bike (electric bike, E-bike), electric bicycle (pedal electric cycle, pedelec), a nautical vessel such as an electric boat or submarine (sub), an aircraft or a spacecraft, which comprises the device previously described and associated with the vehicle or the battery system previously described and associated with the vehicle. 
         [0022]    In an expedient manner, the temperature threshold value can correspond to a predetermined maximum temperature value. In this way, a maximum admissible operating temperature of the energy store can be maintained. In this way, the dependability and service life of the battery cells can be increased. 
         [0023]    In an expedient manner, the temperature threshold value can be determined or codetermined by means of an average temperature value from the plurality of average temperature values. As a result, the battery cells of the energy store can be compared with one another while taking into account the age thereof and the current load thereon. In addition, a provision and storage of predetermined reference values can be eliminated. 
         [0024]    In an expedient manner, the apparatus for determining can be designed as a decentralized pre-processing apparatus. As a result, the transmission of values and the stress on the central processing apparatus can be reduced. In addition, the number of connection lines can be reduced. 
         [0025]    In an expedient manner, the apparatus for determining and/or the apparatus for evaluating and determining can be designed as a central processing apparatus. As a result, the complexity of the monitoring device can be reduced. In addition, the flexibility and maintainability of the monitoring device can be increased. 
         [0026]    In an expedient manner, the battery groups can be designed as partial batteries, battery strings or battery modules. In so doing, the monitoring device can be adapted to the design of the energy store. 
         [0027]    The invention furthermore provides a computer program which is stored on a data carrier or in a memory of a computer and which comprises commands that can be read by the computer and are provided to carry out one of the previously described methods if the commands are executed on a computer. 
         [0028]    The invention furthermore provides for a computer program product which comprises the previously described computer program. 
         [0029]    It is within the scope of the invention for the steps of the method to not necessarily be carried out in the described sequence. In a further embodiment, the steps of the method can also be nested within one another (interleaving). 
         [0030]    It is furthermore possible for individual sections of the described method to be able to be designed as individual saleable units and for the remaining sections of the method to be able to be designed as other saleable units. The method according to the invention can therefore be carried out as a distributed system on different computer-based entities, for example client/server entities. Hence, it is, for example, possible that a module for itself comprises different sub-modules. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    Exemplary embodiments of the invention are depicted in the drawings and are explained in detail in the following description. 
           [0032]    In the drawings: 
           [0033]      FIG. 1  shows a schematic view of an energy store  10  according to the prior art; 
           [0034]      FIG. 2  shows a schematic view of an energy store  20  according to one embodiment of the invention; 
           [0035]      FIG. 3  shows a schematic view of an energy store  30  according to another embodiment of the invention; 
           [0036]      FIG. 4  shows an exemplary temporal temperature profile during a partial breakdown according to the embodiments of the invention; and 
           [0037]      FIG. 5  shows an exemplary temporal temperature profile during a total breakdown according to the embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]      FIG. 2  shows a schematic view of an energy store  20  according to one embodiment of the invention. 
         [0039]    The energy store or respectively the battery system comprises a plurality of battery cells  500   1111  to  500   klmn . Each battery cell can, for example, have a voltage of 4.5 V and a capacity of 60-75 Ah. The plurality of battery cells  500   1111  to  500   klmn  is arranged in a plurality of battery modules  400   111  to  400   klmn , so that each battery module comprises n battery cells. Each battery module can, for example, comprise n=11 to 13 battery cells that are connected in series and therefore have a voltage of 50-60 V and a capacity of 60-75 Ah. The plurality of battery modules  400   111  to  400   klm  is arranged in a plurality of battery strings  300   11  to  300   kl , so that each battery string comprises m battery modules. Each battery string can, for example, comprise m=13 to 20 battery modules which are connected in series and thus have a voltage of 640-1170 V and a capacity of 60-75 Ah. The plurality of battery strings  300   11  to  300   kl  is arranged in a plurality of partial batteries  200   1  to  200   k  so that each partial battery comprises I battery strings. Each partial battery can, for example, can, for example, I=80 battery strings which are connected in parallel and thus have a voltage of 640-1170 V and a capacity 4800-6000 Ah. The plurality of partial batteries  200   1  to  200   k  is arranged as a battery  100  so that the battery k comprises partial batteries. The battery  100  can, for example, comprise k=2 to 4 partial batteries that are connected in parallel and thus have a voltage of 640-1170 V and a capacity of 9600-24000 Ah and comprise in total 22800-374400 battery cells. The battery  100  comprises lines  110   1 ,  110   2  for connecting the partial batteries  200   1  to  200   k ; thus enabling the electrical energy to be available at connections  120   1 ,  120   2 . 
         [0040]    The battery cells  500   1111  to  500   klmn  can be prismatic, for example ashlar-formed, and each comprise a cell housing and a cell cover having in each case two electrical cell connections, for example made of aluminum or copper. The electrical cell connections can each, for example, comprise a threaded hole for the purpose of electrical connection. In order to electrically connect the battery cells  500   1111  to  500   klmn  to the battery modules  400111  to  400   klmn , connection pieces, for example cell connectors, for example made of aluminum or copper, can be used which electrically connect the cell connections of the battery cells  500   1111  to  500   klmn  to one another according to the respective requirement. In order to manufacture a battery module  400111  to  400   klmn , the connection pieces can, for example, be welded to the cell connections, for example by means of a laser, in accordance with the spatial orientation of the battery cells  500   1111  to  500   klmn . 
         [0041]    The battery cells  500   1111    to 500   klmn  can be designed as primary cells or respectively primary elements which are not rechargeable or as secondary elements which are rechargeable. The secondary cells can, for example, be designed as a lithium-ion battery (lithium battery, lithium-ion battery, Li-ion battery, Li-ion secondary battery) or as a lithium-polymer accumulator (Li-poly battery, LiPo battery). The battery cells  500   1111  to  500   klmn  can be designed comprising an electrode coil (jelly roll, JR, Swiss roll), for example as a lithium-ion battery comprising an electrode coil (JR-Li-ion battery). The battery cells  500   1111  to  500   klmn , can be designed as a pouch cell. In so doing, a pouch, which is used to receive and accommodate an electrolyte, can comprise one, two, three or more electrode coils. In addition, a protective envelope can enclose the pouch or pouches. The protective envelope can comprise a resistant (shock-proof, bulletproof, ballistic, anti-ballistic) material, for example ballistic fabric, such as ballistic polyamide fabric (ballistic nylon fabric, ballistic nylon). Hence, the electrode coils can be protected against damage from the outside, for example in the event of an accident, and/or in the event of a thermal runaway of an electrode coil, which can exert considerable force on adjacent battery cells. 
         [0042]    The energy store  20  further comprises a temperature-control device for controlling the temperature, i.e. cooling or heating, of the battery cells  500   1111  to  500   klmn  by means of a temperature-control medium, for example a liquid like alcohol, for example propane-1,2,3-triol (glycerol, glycerin), oil or water, for example salt water or a liquid mixture. A cooling agent such as a coolant (air-heat radiator) or a refrigerant which evaporates due to the heat (evaporator) can, for example, absorb the heat of the battery cells  500   1111  to  500   klmn  and discharge said heat via a radiator or heat exchanger  800  to the surrounding environment or to an air conditioning system (AC). The temperature control device comprises heat exchangers for exchanging the heat between the battery cells  500   1111  to  500   klmn  and the temperature-control medium that flows through the temperature-control device. The heat exchangers can, for example, be designed as cooling plates. Each battery module  400   111  to  400   klm , can, for example, comprise a cooling plate or a plurality of cooling plates. The battery cells  500   1111  to  500   klmn  can be mounted on the cooling plates. 
         [0043]    The temperature-control device further comprises connection devices such as inflow lines  150 ,  150   1 - 150   k ,  150   11 - 150   kl  and outflow lines  170 ,  170   1 - 170   k  for connecting the components of the temperature-control device. The connection devices can be designed as tubes and/or pipes and comprise, for example, plastic or metal such as aluminum, iron or steel. As is shown by way of example in  FIG. 2 , the inflow of the temperature-control medium in the direction of the battery cells  500   1111  to  500   klmn  can, for example, take place via a main inflow line  150 , partial battery inflow lines  150   1 - 150   k , which branch off from the main inflow line  150  and battery string inflow lines  150   11 - 150   kl , which in each case branch off from the partial battery inflow lines  150   1 - 150   k . After the heat exchange with the battery cells  500   1111  to  500   klmn , the outflow of the temperature-control medium, as shown by way of example in  FIG. 2 , can take place via battery string outflow lines  170   11 - 170   kl , which each open into partial battery outflow lines  170   1 - 170   k  that open into a main outflow line  170 . 
         [0044]    The temperature-control device can furthermore comprise actuating devices for blocking and/or controlling the temperature-control medium flow. The actuating devices can, for example, be designed as shut-off devices such as shut-off cocks, shut-off valves or shut-off slides or as valves such as manually actuated valves, electromotively actuated valves or electromagnetic valves. The inflows of the temperature-control medium in the direction of the battery cells  500   1111  to  500   klmn  can, for example, as shown by way of example in  FIG. 2 , be discretely or respectively individually controlled by means of battery string inflow valves  160   11 - 160   kl  which in each case are disposed in battery string inflow lines  150   11 - 150   kl . After the heat exchange with the battery cells  500   1111  to  500   klmn , the outflows of the temperature-control medium, as shown by way of example in  FIG. 2 , can be discretely or respectively individually controlled by means of battery string outflow valves  180   11 - 180   kl , which are disposed in each case in the battery string outflow lines  170   11 - 170   kl . In order to control or shut-off the flow, the inflow valves  160   11 - 160   kl  and the respectively corresponding outflow valves  180   11 - 180   kl  can be controlled in pairs. 
         [0045]    The temperature-control device can comprise the heat exchanger  800  which is connected to the main inflow line  150  and the main outflow line  170 ; thus enabling the temperature-control device to have a (closed) temperature-control medium circuit. The temperature-control device can furthermore comprise a delivery apparatus  900  such as a pump that is connected to the main inflow line 150  or to the main outflow line  170 ; thus enabling the temperature-control medium flow to be reinforced or controlled. 
         [0046]    The energy store  20  further comprises a monitoring device for monitoring the energy store  20  and the battery cells  500   1111  to  500   klm . The monitoring device comprises a plurality of sensor apparatuses  720  for sensing temperature measurement values of the battery cells  500   1111  to  500   klmn  and a processing apparatus  740  for processing the sensed temperature measurement values. The processing apparatus  740  can comprise an interface  746  for transmitting or receiving the sensed temperature measurement values, a store  744  such as a read-write memory (random access memory, RAM) for storing the received temperature measurement values and a processor such as a microprocessor or microcontroller for processing the stored temperature measurement values by means of the stored commands. The sensor apparatuses  720  are disposed in such a way that said apparatuses can sense the temperatures of the battery cells  500   1111  to  500   klmn  and are connected via lines  730 , directly or indirectly, to the interface  760 . A sensor apparatus  720  is preferably associated with each battery cell  500   1111  to  500   klmn ; thus enabling the temperature of each battery cell  500   1111  to  500   klmn  to be sensed. 
         [0047]    The monitoring device can further comprise a plurality of pre-processing apparatuses for pre-processing the sensed temperature measurement values, a number of the plurality of sensor apparatuses  720  being associated with each pre-processing apparatus  710 . The pre-processing apparatuses  710  can, as is shown by way of example in  FIG. 3 , each be associated with a battery string  300   11 - 300   kl . Alternatively, the pre-processing apparatuses  710  can each be associated with a battery module  400   111 - 400   klmn  or a partial battery  200   1 - 200   k . The pre-processing apparatuses  710  are however associated in accordance with the structure of the inflow lines  150 ,  150   1 - 150   k ,  150   11 - 150   kl  and/or outflow lines  170 ,  170   1 - 170   k ; thus enabling the battery cells  500   1111  to  500   klmn  associated with the number of sensor apparatuses  720  to be temperature-controlled by a (partial) flow of the temperature-control medium. The pre-processing apparatuses  710  can, similar to the pre-processing apparatus  740 , process temperature measurement values sensed by the number of associated sensor apparatuses  720 ; thus enabling the pre-processing of all of the sensed temperature measurement values to be parallelized and/or the transmission of the temperature measurement values to be simplified. An averaging can, for example, already take place in the respective pre-processing apparatuses  710 . A monitoring method can thus be carried out distributed over the processing apparatus  740  and the plurality of pre-processing apparatuses  710 . 
         [0048]    A monitoring method for monitoring the energy store  20 , in particular the temperature thereof, and therefore also the temperature-control device of said energy store comprises initially a sensing of the temperatures of each battery cell  500   1111  to  500   klmn  by means of the sensor apparatuses  720  as sensed temperature measurement values and if need be a repetition of the sensing. The monitoring method can further comprise selecting temperature measurement values from the sensed temperature measurement values. The monitoring method can further comprise determining average temperature values (averaging) in each case from the selected temperature measurement values, wherein the selected temperature measurement values can in each case be associated with a group of battery cells  500   111 - 500   klm (battery group), such as a partial battery  200   1 - 200   k , a battery string  300   11 - 300   kl  or a battery module  400   111 - 400   klnm , so that the average temperature values for each partial battery  200   1 - 200   k  (partial battery average temperature), each battery string  300   11 - 300   kl  (battery string average temperature) and/or each battery module  400   111 - 400   klmn  (battery module average temperature) can be determined. The monitoring method can furthermore comprise determining of temperature maximum values in each case from the selected temperature measurement values, wherein the selected temperature can in each case be associated with a partial battery  200   1 - 200   k , a battery string  300   11 - 300   kl  or a battery module  400   111 - 400   klmn  , thus enabling the temperature maximum values to be determined for each partial battery  200   1 - 200   k  (partial battery maximum temperature), each battery string  300   11 - 300   kl  (battery string maximum temperature) and/or each battery module  400   111 - 400   klmn  (battery module maximum temperature). The monitoring method can accordingly comprise determining temperature minimum values in each case from the selected temperature measurement values. Determining the average temperature value from the selected temperature measurement values, determining the temperature maximum values and/or determining the temperature minimum values preferably takes place in each case by means or the pre-processing apparatuses  710 . 
         [0049]    The monitoring method can furthermore comprise determining an average temperature value (averaging) from the determined average temperature values, i.e. from the partial battery average temperatures, the battery string average temperatures or the module average temperatures. The monitoring method can furthermore comprise determining a maximum average temperature value from the average temperature values; thus enabling the maximum partial battery average temperature (the “hottest” partial battery), the maximum battery string average temperature (the “hottest” battery string) or the maximum battery module average temperature (the “hottest” battery module) to be determined. The monitoring method can furthermore comprise determining a minimum average temperature value from the determined average temperature values; thus enabling the minimum partial battery average temperature value (the “coolest” partial battery), the minimum battery string average temperature (the “coolest” battery string) or the minimum battery module average temperature (the “coolest” battery module) to be determined. Determining the average temperature value, the maximum average temperature value and/or the minimum average temperature value from the determined average temperature values takes place preferably by means of the processing apparatus  740 . 
         [0050]    The monitoring method can furthermore comprise comparing the determined average temperature values to one another or respectively among one another. As a result, this comparing of the determined average temperature values can comprise comparing the determined average temperature values to the determined average temperature value (of the determined average temperature values). If the comparison of the determined average temperature values with one another results in a significant difference of one of the determined average temperature values, the monitoring method can recognize a defect of the temperature-control device, the position of which corresponds to the different determined average temperature value, in particular if the charging or respectively discharging of the energy store  20  takes place within the scope of the electrical specification. 
         [0051]    The monitoring method can furthermore comprise a comparison of the determined average temperature values, the determined average temperature value and/or the maximum average temperature value with a predetermined temperature value T k , which corresponds to the critical operating temperature of the energy store  20 , and an outputting of a command for the maximum operation of the temperature-control device. The comparison and output of the command for maximum operation preferably takes place by means of the processing apparatus  740 . 
         [0052]    The monitoring method can furthermore comprise a comparison of the determined average temperature values, the determined average temperature value and/or the maximum average temperature value with a predetermined maximum temperature value T max , which corresponds to the maximally admissible operating temperature of the energy store  20 , and an outputting of a command to deactivate the energy store  20 . If the comparison of the determined average temperature values or the determined average temperature value with the predetermined maximum temperature value T max  results in the maximum temperature value T. being exceeded, the monitoring method can detect a defect of the temperature-control device, for example along the inflow lines  150 ,  150   1 ,  150   11 - 150   kl  and the main flow line  170 ,  170   1 ,  170   11 - 170   kl , in particular if the charging or discharging of the energy store takes place within the scope of the electrical specification. A determined battery string average temperature of the battery string  300   12  being exceeded can, for example, identify or respectively detect and signal a blockage of the battery string inflow line  150   12  or respectively the battery string outflow line  170   12  or a breakdown of the inflow valve  160   12  or respectively outflow valve  180   12  in a closed position. A determined partial battery average temperature of the partial battery  200   k  being exceeded can correspondingly identify or respectively detect and signal a blockage of the partial battery inflow line  150   k  or respectively the partial battery outflow line  170   k . In addition, a plurality of determined average temperature values being jointly exceeded, for example of determined battery string average temperatures of the battery strings  300   12 - 300   11 , can identify or respectively detect a blockage of the partial battery inflow line  150   1  and limit said blockage to a section between the battery string inflow lines  150   11  and  150   12  because the determined battery string average temperature of the battery string  300   11  not being exceeded signals a free partial battery outflow line  170   1 . The comparison and outputting of the command for deactivation preferably takes place by means of the processing apparatus  740 . 
         [0053]      FIG. 3  shows a schematic view of an energy store  30  according to another embodiment of the invention. 
         [0054]    The energy store  30  shown in  FIG. 3  corresponds substantially to the energy store  20  described with reference to  FIG. 2 . The inflows of the temperature-control medium in the direction of the battery cells  500   1111  to  500   klmn  can, as shown by way of example in  FIG. 3 , be controlled by means of partial battery inflow valves  160   1 - 160   k  which are disposed in the partial battery inflow lines  150   1 - 150   k . After the heat exchange with the battery cells  500   1111  to  500   klmn , the outflows of the temperature-control medium, as shown by way of example in  FIG. 3 , can be controlled by means of partial battery outflow valves  180   1 - 180   k  which are disposed in the partial battery outflow lines  170   1 - 170   k . 
         [0055]      FIG. 4  shows an exemplary temporal temperature profile during a partial breakdown according to the embodiments of the invention. 
         [0056]    The points in time t 40  to t 42  are marked along a horizontal time axis t. An admissible temperature range comprising a predetermined minimum temperature T min , for example +25° C., and a predetermined maximum temperature T max , for example +40° C., and a critical temperature T k , for example +35° C., for activating the maximum operation of the temperature-control device are marked along a vertical temperature axis T. Certain battery string average temperatures T 300(12) , T 300(xy)  of the battery strings  300   12 - 300   kl  of the energy store depicted in  FIG. 2  and the average temperature value T mittel  obtained therefrom are plotted by way of example in the temporal profile. 
         [0057]    A defect occurs in the temperature control device with regard to the battery string  300   12  at the point in time t 40 , for example a blockage of the battery string inflow line  150   12  or the battery string outflow line  170   12  or a breakdown of the inflow valve  160   12  or the outflow valve  180   12  in a closed position. As a result of the partial breakdown of the cooling process, the determined battery string average temperature T 300(12)  of the battery string  300   12  and thereby also proportionally the determined average temperature value T mittel  increase. 
         [0058]    The determined battery string average temperature T 300(12)  of the battery string  300   12  reaches the critical temperature T k  at the point in time t 41 , and the monitoring device induces the maximum operation of the temperature-control device. The determined battery string average temperature T 300(12)  of the battery string  300   12  and also the determined average temperature value T mittel  continue to rise. 
         [0059]    The determined battery string average temperature T 300(12)  of the battery string  300   12  reaches the maximum temperature T max  at the point in time t 42 , and the monitoring device induces a deactivation of the energy store  20 . Prior to this event or alternatively, the monitoring device can deactivate the affected battery string  300   12 . 
         [0060]      FIG. 5  shows an exemplary temporal temperature profile when a total breakdown occurs pursuant to the embodiments of the invention. 
         [0061]    The points in time t 50  to t 52  are marked along a horizontal time axis t. The admissible temperature range, comprising the predetermined minimum temperature T min  and the predetermined maximum temperature T max , and the critical temperature T k  are marked along a vertical temperature axis T, as was already described with regard to  FIG. 4 . Certain battery string average temperatures T 300(xy)  of the battery strings  300   12 - 300   kl  of the energy store depicted in  FIG. 2  and the average temperature value T mittel  obtained therefrom are plotted by way of example in the temporal profile. 
         [0062]    For example, a blockage of the battery inflow line  150  or the battery outflow line  170  or a breakdown of the pump  900  occurs in the temperature-control device at the point in time t 50 . As a result of the of the total breakdown of the cooling process, the determined battery string average temperatures T 300(xy)  of the battery strings  300   12 - 300   kl  and thereby also the determined average temperature value T mattel  rise. 
         [0063]    The determined battery string average temperatures T 300(xy)  of the battery strings  300   12 - 300   kl  or respectively the determined average temperature value T mittel  reach the critical temperature T k  at the point in time t 51 , and the monitoring device induces the maximum operation of the temperature-control device. The determined battery string average temperatures T 300(xy)  of the battery strings  300   12 - 300   kl  and also the determined average temperature value T mittel  continue to rise. 
         [0064]    The determined battery string average temperatures T 300(xy)  of the battery strings  300   12 - 300   kl  or respectively the average temperature value T mittel  reach the maximum temperature T max  at the point in time t 52 , and the monitoring device induces a deactivation of the energy store  20 . 
         [0065]    The features of the energy store  20 ;  30 , for example of the valves shown in  FIGS. 2 and 3 , can be combined with one another.