DEVICE AND METHOD FOR CONTROLLING THE TEMPERATURE OF AN ENERGY STORAGE DEVICE FOR ELECTRICAL ENERGY OF A MOTOR VEHICLE

Description

[0001] The invention relates to a device and a method for controlling the temperature of an energy storage device for electrical energy in a motor vehicle. The invention further relates to a motor vehicle, preferably a commercial vehicle, with such a device.

[0002] Motor vehicles that are at least partially electrically powered generally have an energy storage device for electrical energy, hereinafter also referred to as an electrical energy storage device. The electrical energy storage device can be a high-voltage (HV) motor vehicle battery. Various methods are known in practice for not only cooling but also heating a high-voltage battery. One possibility is the heating of water glycol using heating / cooling fins in the base of the HV battery. Other approaches include heating the cell or generating reactive power, e.g. via the arrester. However, motor vehicles are often only actively in use for a fraction of the time. There is therefore a possibility that the electrical energy storage device, in particular the individual battery cells, cools down when the vehicle is parked.It is known that temperatures that are too high or too low can adversely affect the service life, performance, and functionality of such a battery. In particular, the problem arises that below a critical minimum temperature, the battery cells of the energy storage unit are no longer able to provide sufficient power for starting operation when the vehicle is restarted. If the HV battery cools down too much, for example, only little or no current can be provided from the cells, especially for heating, since the current limits of the cells depend on the state of charge (SoC) and the temperature. Another disadvantage of known approaches to heating HV batteries is that they consume a lot of energy.

[0003] DE 11 2012 001739 discloses a device and a method for tempering an energy storage device in which only a predetermined portion of the tempering fluid is heated by a heating device.

[0004] It is therefore an object of the invention to provide a device for controlling the temperature of an electrical energy storage device that avoids the disadvantages of conventional techniques. The object of the invention is, in particular, to provide an approach for controlling the temperature of an energy storage device that prevents the electrical energy storage device from cooling down even when the vehicle is parked, and thus enables the electrical energy storage device to be heated as energy-efficiently as possible even when the vehicle is parked.

[0005] These objects are achieved by a device and a method having the features of the independent claims. Advantageous embodiments and applications of the invention are subject to the dependent claims and are explained in more detail in the following description, with partial reference to the figures.

[0006] According to a first general aspect of the invention, a device for controlling the temperature of an energy storage device for electrical energy of a motor vehicle is provided. The motor vehicle can be an electrically driven and / or powered motor vehicle. The device comprises an energy storage device for electrical energy, hereinafter also referred to as electrical energy storage device or simply as energy storage device.

[0007] The device further comprises a fluid circuit that is thermally coupled and / or coupled to the energy storage device for controlling the temperature of the energy storage device, wherein a temperature control fluid can be supplied to and removed from the energy storage device through the fluid circuit. The fluid circuit can comprise a pump device for transporting the temperature control fluid through the fluid circuit, a valve device, a cooling device for cooling the temperature control fluid, and a heating device for heating the temperature control fluid. The fluid circuit further comprises a subcircuit in which the heating device is arranged. This subcircuit is also referred to below as the first subcircuit. The fluid circuit can thus serve optionally as a cooling circuit and a heating circuit.

[0008] According to the invention, the device is designed to activate a heating operation of the heating device when the motor vehicle is parked and when a predetermined heating condition is met, wherein a fluidic coupling of the partial circuit with the fluid circuit and a supply and discharge of tempering fluid heated in the partial circuit to the energy storage device for electrical energy can be controlled by means of the valve device.

[0009] This prevents the energy storage device from cooling down even when the vehicle is parked. Furthermore, particularly energy-efficient heating of the temperature control fluid and thus energy-efficient heating of the energy storage device is possible, since the heating device arranged in the partial circuit can only heat a portion of the temperature control fluid, which can then be selectively fed to the energy storage device for local heat dissipation via the valve device. Thermal losses can be reduced accordingly. At the same time, a cost-effective implementation of the device is possible, since there is no separate heating circuit from the cooling circuit, but rather the latter is integrated into the cooling circuit.

[0010] Preferably, a parked vehicle should be understood as a parked and / or shut-off state of the motor vehicle, in particular a resting operating state of the motor vehicle, e.g. when the motor vehicle is parked.

[0011] According to the invention, only a portion of the temperature control fluid is heated by the heating device during heating operation. According to the invention, the device is designed, in a first step, to heat a portion, preferably a predetermined portion, of the temperature control fluid in the partial circuit by the heating device when heating operation is activated, wherein the partial circuit is fluidically separated from the remaining fluid circuit and / or the energy store by means of the valve device. According to the invention, the device is further designed, in a second step, to fluidically connect the partial circuit to the energy store by means of the valve device and to pump the heated predetermined portion to the energy store by means of the pump device.

[0012] In this case, in the first step and / or in the second step, a further, second sub-circuit, in which the cooling device is arranged, can be fluidically separated from the remaining fluid circuit, which comprises the first sub-circuit and the section with the energy storage device. The predetermined sub-quantity of the temperature control fluid can be determined by the size and / or fluid absorption capacity of the first sub-circuit and / or by the position of individual valves of the valve device for fluidically coupling the first sub-circuit with the fluid circuit. This enables particularly energy-efficient heating of the energy storage device because, on the one hand, it can be avoided that the entire quantity of temperature control fluid in the fluid circuit is heated during heating operation and that energy is consumed for this purpose. Thermal losses due to the thermal capacity of the fluid circuit can thus be reduced.This is particularly advantageous when a parked vehicle is not connected to an external power supply or charging station, and the energy of the energy storage unit is provided, for example, by the energy storage unit itself or another vehicle battery. Accordingly, the lower energy consumption prevents the energy storage unit from discharging too quickly during heating. Furthermore, a portion of the temperature control fluid can be heated faster than the entire amount, thus accelerating the overall heating process.

[0013] In an advantageous variant of this embodiment, the device can be configured to perform multiple sequences for heating the energy storage device when the heating mode is activated, wherein each sequence comprises the first and second steps, preferably such that sequential pulses of heated partial quantities of the temperature control fluid are pumped to the energy storage device instead of a continuous flow of temperature control fluid. In other words, multiple sequences with heated temperature control fluid are pumped into the energy storage device one after the other and / or in pulsed form. This allows the required quantity of heated temperature control fluid to be determined more precisely and / or the required quantity of temperature control fluid required to prevent the energy storage device from cooling down too much to be reduced.

[0014] According to the invention, in a first alternative, the device can be designed to control the valve device and the pump device in a second step such that the heated, predetermined partial quantity is pumped into the flow area of ​​the energy storage device and remains there for a minimum period of time by stopping the fluid flow. This achieves a particularly efficient thermal coupling with the energy storage device, since a large portion of the heat of the heated temperature control fluid can be transferred specifically to the energy storage device and only a smaller portion to other line segments. Furthermore, sequential pumping operation is more energy-efficient than continuous operation of the temperature control fluid.

[0015] Furthermore, the energy storage device can be thermally coupled to the fluid circuit via a flow-through region formed in a wall region, preferably in a base plate, of the energy storage device. Optionally, the predetermined portion of the temperature control fluid that is heated in the first step can correspond to a capacity of the flow-through region of the energy storage device. In other words, in heating mode, only as much fluid is heated as the wall region and / or the base plate of the energy storage device can absorb in terms of temperature control fluid for thermal coupling. This variant allows the energy required for heating mode to be reduced particularly efficiently, enabling particularly energy-efficient heating of the energy storage device.The fluid circuit can thus be used either as a cooling circuit (in cooling mode) or a heating circuit (in heating mode). However, particularly in heating mode, thermal losses are reduced due to the thermal capacity of the fluid circuit, since only the thermal capacity of the partial circuit and / or the partial amount of tempering fluid heated therein is used in heating mode. The device is preferably further configured such that the direction of the fluid mass flow in cooling mode is the same as in heating mode.

[0016] According to a second alternative of the invention, the predetermined portion of the temperature control fluid heated in the first step can be in the range of 80% - 200%, more preferably 90% - 130%, of the absorption capacity of the flow area. Practical tests have shown that good results can also be achieved with these ranges. It is therefore advantageous if the temperature control fluid is not heated over the entire length of the fluid circuit piping, but only a portion of it.

[0017] The term "partial circuit" in this context is to be understood as meaning that the fluid circuit has a sub-segment in which only a portion of the temperature control fluid of the fluid circuit can circulate and / or be heated by the heating device. According to one embodiment, the partial circuit can have a capacity for temperature control fluid that is less than 50%, more preferably less than 30%, or less than 20%, of the capacity of the entire fluid circuit. This offers the advantage that, for heating operation when the vehicle is parked, a relatively small amount of temperature control fluid can be heated in order to keep the energy consumption for heating as low as possible, while, in cooling operation, the entire amount of temperature control fluid is preferably available in order to reliably prevent overheating of the energy storage device, particularly when the vehicle is in motion.

[0018] According to a further aspect, the device for controlling the temperature of the energy storage device can comprise an electrical sub-system of the motor vehicle, which is and / or can be supplied with electrical voltage when the ignition is switched off and / or the battery main switch of the motor vehicle is pulled. In this way, when the vehicle is parked, it is not necessary to supply the entire vehicle electrical system with power, but rather only an electrical sub-system, which supplies electrical energy to the heating device for heating operation and optionally to other components, such as sensor devices for monitoring the predetermined heating condition, for example, the energy storage temperature.Such partial network operation is particularly advantageous for trucks, where it is common practice today for truck drivers to pull the battery main switch (of the 24V starter battery) when parking or leaving the vehicle overnight or over the weekend, thus deactivating the on-board network functions. Accordingly, one embodiment of the invention provides that even when the vehicle is parked and / or the battery main switch is pulled, the partial on-board network in which the heating device for the energy storage device is located can still be supplied with power.

[0019] The supply of electrical energy can be provided by the energy storage device itself, with the heating device being an electrically operated heating device located in the sub-vehicle electrical system. Alternatively or additionally, the energy storage device can also be supplied with electrical energy via another battery of the motor vehicle and / or via an external power supply, for example, if the vehicle is parked at a charging station.

[0020] According to a further aspect, the fluid circuit can comprise two parallel lines in which the heating device and the cooling device are arranged fluidically parallel to one another. The valve device can be used to control which of the parallel lines a fluid flow can be and / or is supplied to the energy storage device. This offers the advantage that the fluid flows for the heating and cooling modes of the device can be controlled accordingly.

[0021] For example, the device can be designed to fluidically decouple a line section having the cooling device from a line section having the energy storage device by means of the valve device in the second step described above, so that heated tempering fluid is conveyed directly to the energy storage device and not to the cooling device.

[0022] A predetermined heating condition is understood to be a predefined condition or a predefined criterion that indicates or can be derived from when, particularly when the vehicle is parked, the energy storage device is at risk of cooling down too much and proper functioning can no longer be guaranteed and / or would result in excessive aging effects on the energy storage device. The predetermined heating condition can be met, for example, if a temperature of the energy storage device falls below a predetermined threshold value. A suitable threshold value for the respective energy storage device can be determined and set experimentally. For this purpose, the device can have a sensor device, for example at least one temperature sensor, which monitors the energy storage device temperature and / or the temperature of one or more storage cells of the energy storage device.Instead of the energy storage temperature, another variable can be monitored alternatively or additionally as part of the heating condition monitoring, for example, the ambient temperature and / or the temperature of the temperature control fluid in the fluid circuit. The temperature of the energy storage device can also be estimated from the course of these variables, e.g., using a previously experimentally determined characteristic curve.

[0023] According to a further aspect, the pump device can comprise a first pump arranged in the partial circuit for conveying the temperature control fluid within the partial circuit. Alternatively or additionally, the pump device can comprise a second pump arranged outside the partial circuit for conveying temperature control fluid to the energy storage device.

[0024] According to a further aspect, the device can be configured to deactivate the first pump, as described above, only after a follow-up time after deactivation of the heating device in order to avoid cavitation effects. Such a follow-up operation avoids or at least reduces disruptive cavitation effects during heating operation.

[0025] The device may further comprise a control device which is designed to control the components of the fluid circuit, in particular the heating device, the cooling device and / or the valve device.

[0026] As stated above, the device is designed to control one or more components of the fluid circuit to implement heating operation. This can be achieved, for example, by appropriately designing the control device. The control device can comprise one or more control units or be implemented as part of such control units. Part of the functionality of the control device can also be implemented, for example, in the battery management system (BMS), e.g., to monitor the temperature of the energy storage device.

[0027] According to a further embodiment, thermal insulation can be provided on or adjacent to the heating device. This can reduce heat radiation losses and improve energy efficiency during heating.

[0028] The temperature control fluid can be a glycol-water mixture in a conventional manner.

[0029] The electrical energy storage device can be a high-voltage battery, an electrical traction energy storage device and / or a lithium-ion accumulator energy storage device.

[0030] The invention further relates to a motor vehicle with a device for controlling the temperature of an energy storage device as disclosed in this document. The motor vehicle can be an electrically driven and / or powered motor vehicle. The motor vehicle can be a commercial vehicle, such as a truck or bus.

[0031] According to a second general aspect of the invention, a method for controlling the temperature of an energy storage device for electrical energy of a motor vehicle is provided, wherein the energy storage device is and / or can be thermally coupled to a fluid circuit for controlling the temperature of the energy storage device, and wherein a temperature control fluid can be supplied to and discharged from the energy storage device through the fluid circuit. The fluid circuit comprises a pump device for transporting the temperature control fluid through the fluid circuit, a valve device, a cooling device for cooling the temperature control fluid, and a heating device for heating the temperature control fluid. The fluid circuit has a sub-circuit in which the heating device is arranged.

[0032] The method comprises monitoring a predetermined heating condition when the motor vehicle is parked and, when a predetermined heating condition is met, activating a heating operation of the heating device, wherein the valve device controls a fluidic coupling of the partial circuit to the fluid circuit and a supply and discharge of tempering fluid heated in the partial circuit to the energy storage device for electrical energy.

[0033] To avoid repetition, features disclosed purely in accordance with the device shall also be deemed to be disclosed in accordance with the method and shall be claimable. The aforementioned aspects and features of the invention, particularly with regard to the design of the device, the fluid circuit, and the functional implementation of the device, thus also apply to the method.

[0034] The above-described preferred embodiments and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. They show: Figure 1 shows a highly schematic view of a device for controlling the temperature of an energy storage device in a first step of the heating operation according to an embodiment of the invention; Figure 2 shows the device from Figure 1 in a second step of the heating operation according to an embodiment of the invention; and Figure 3 shows a flowchart illustrating the mode of operation of the temperature control device and a method for temperature control of the energy storage device according to an embodiment of the invention.

[0035] Identical or equivalent elements are designated by the same reference numerals in all figures and some are not described separately.

[0036] Figure 1shows a device 1 for controlling the temperature of an energy storage device 5 for electrical energy of a motor vehicle according to an embodiment of the invention. The motor vehicle can be an electrically powered motor vehicle, for example, a truck. The energy storage device 5 is an HV energy storage device and supplies an electric machine (not shown) of the motor vehicle with electrical traction energy and absorbs recuperated energy.

[0037] The device 1 further comprises a fluid circuit 3 thermally coupled to the energy storage device 5 for controlling the temperature of the energy storage device 5. A temperature control fluid, e.g., water-glycol, can be supplied to and removed from the energy storage device 5 through the fluid circuit. For this purpose, a flow-through region 6 is provided in the bottom region of the energy storage device, through which the temperature control fluid can flow. In the flow-through region, the temperature control fluid can optionally flow around fins serving as heating or cooling fins to achieve thermal coupling with the energy storage device 5.

[0038] The fluid circuit 3 comprises a pump device, which in this case comprises a first pump 10 and a second pump 11 for transporting the temperature control fluid through the fluid circuit 3. The fluid circuit 3 further comprises a valve device 12, which in this case comprises a plurality of solenoid valves 12a to 12d.

[0039] A cooling device 8 for cooling the temperature control fluid is arranged in line section 14. The cooling device 8 can be designed in a conventional manner and is therefore not described in detail here. In cooling mode, the cooling device 8 cools the temperature control fluid flowing through it.

[0040] In a line section 15 parallel to the line section 14, a heating device 9 for heating the tempering fluid is arranged. The heating device 9 is arranged in a fluidic subcircuit 4, in which the first pump 10 is also arranged. The heating device is at least partially encased by thermal insulation 17, which in Figure 1 is only presented in a very schematic manner.

[0041] Furthermore, the device 1 comprises a control device 2, which is signal-connected to the individual components of the fluid circuit 3 via signal lines, which are shown in dashed lines. The control device 2 is configured to control the individual components of the fluid circuit 3. Part of the functionality of the control device 2 is also implemented in the battery management system (BMS) 5a of the energy storage device, wherein the BMS is used to monitor the temperature of the energy storage device 5.

[0042] The heating device 9 is designed as an electrical high-voltage (HV) heater, which is supplied with electrical energy from the energy storage device 6 via an electrical sub-network 7, shown here only very schematically by the dot-dash line. The special feature here is that this sub-network 7 is supplied with power even when the vehicle is parked and the ignition key is removed, while other parts of the vehicle's electrical system are deactivated. The control device 2 and the energy storage device 9 are supplied with electrical energy via this sub-network 7, even when the vehicle is parked. Furthermore, electrical control of the magnetic valve device 12 is enabled.

[0043] The fluid circuit 3 can be used either for cooling the energy storage device 6 or for heating the energy storage device 6, depending on whether cooled tempering fluid is conveyed to the energy storage device 6 via the cooling device 8 or heated tempering fluid is conveyed to the energy storage device 6 via the heating device 9. The direction of circulation of the mass flow is the same in heating and cooling mode.

[0044] During normal driving operation of the motor vehicle, the energy storage device 6 generally needs to be cooled, so that during driving operation, the partial circuit 4 is normally fluidically decoupled from the remaining fluid circuit 3 by means of the valve device 12. For this purpose, the valves 12c and 12d can be switched by the control device 12 such that the fluid line 14 is fluidically connected to the fluid line 16 and the fluid line 15 is not fluidically connected to the fluid lines 14 and 16. Tempering fluid cooled by the cooling device 8 thus flows through a fluid circuit formed by the lines 14 and 16 into the flow area 6 of the energy storage device 5 and back to the cooling device.

[0045] However, as already mentioned above, when the vehicle is not in operation and the outside temperature is cold, the problem may arise that the energy storage device 6 cools down too much. This may adversely affect the service life, performance, and functionality of the energy storage device and may result in the energy storage device no longer being able to provide sufficient power for starting operation when the vehicle is restarted.

[0046] Accordingly, the temperature control device 1 is also used, if necessary, to heat the energy storage device 5 when the vehicle is parked, which is explained below.

[0047] For this purpose, the control device 2 is designed to monitor whether a predetermined heating condition is met when the vehicle is parked. For example, the temperature of the energy storage device 6 is monitored, with this temperature monitoring being carried out by the battery management system (BMS) 5a of the energy storage device 5, which also monitors the temperature of the energy storage device during driving operation using temperature sensors in the energy storage device 5. The BMS can use the so-called cell module controller (CMC) to monitor the voltage and the temperature sensor installed in each cell module. This temperature monitoring when the vehicle is parked corresponds to step S1 according to the flowchart from Figure 3 .

[0048] At a specific time t, the BMS measures the temperature. If the temperature falls below a specific limit, this is considered fulfillment of the heating condition, and the control device 2 controls the partial circuit 4 and the heating device 9 to start heating operation. This is described as step S2 in Figure 3 shown.

[0049] To start heating operation, in a first step S3, the control device 2 first controls the valves 12a and 12b so that fluid can circulate in the partial circuit 4 but cannot leave it, and activates the pump 10 and the heating device 9 in the partial circuit 4. A small partial quantity 20 of the temperature control fluid thus circulates in the partial circuit 4 and is heated by the heating device 9. The partial circuit 4 is designed such that the partial quantity 20 approximately corresponds to the amount of fluid that the energy storage device 6 can absorb in its base plate in the flow area.

[0050] The temperature of the heated tempering fluid is measured in the heating device 9. Once the tempering fluid in the partial circuit 4 has reached a certain temperature, the control device, in a second step S4, controls the pumps 10 and 11 and the valves 12a to 12d such that the partial quantity 20 of the heated tempering fluid 20 is conveyed from the partial circuit to the flow area 6 of the energy storage device. This conveyance of the heated partial quantity 20 of the tempering fluid is Figure 2 schematically illustrated by the arrows and the moving box 20.

[0051] Here, the valves 12c and 12d are switched such that the fluid lines 15 and 16 are fluidically connected to one another. In other words, in the second step S4, the valve device 12 and the pumps 10, 11 are controlled such that the heated partial quantity 20 of the temperature control fluid is pumped into the flow area 9 and, by stopping the fluid flow, remains there for a minimum period of time to transfer the heat to the energy storage device 6.

[0052] When the heating operation is activated, several such sequences are carried out to heat the energy storage device 9, each sequence comprising the first (S3) and second (S4) step, so that sequential pulses of heated partial quantities 20 of the temperature control fluid are pumped to the energy storage device 9 instead of a continuous temperature control fluid flow.

[0053] This is repeated until the temperature of the cell modules exceeds a certain temperature. Heating operation is then terminated and heating device 9 is deactivated. To avoid cavitation effects, pump 10 is deactivated only after a certain run-on time.

[0054] Although the invention has been described with reference to specific embodiments, it will be apparent to a person skilled in the art that various changes can be made and equivalents can be used as substitutes without departing from the scope of the invention. By way of example only, it should be mentioned that the described configuration of the fluid circuit 3 and in particular of the valve device 12 is merely exemplary and, of course, more or fewer valves in different designs and configurations can be used. Consequently, the invention is not intended to be limited to the disclosed embodiments, but is intended to include all embodiments that fall within the scope of the appended claims. In particular, the invention also claims protection for the subject matter and features of the subclaims, independent of the claims referred to. List of reference symbols

[0055] 1Temperature control device 2Control device 3Fluid circuit 4Subcircuit 5Electrical energy storage 5aBattery management system (BMS) 6Flow area 7Sub-vehicle power supply 8Cooling device 9Heating device 10First pump 11Second pump 12Valve device 12a, 12b, 12c, 12dValves 14Fluid line 15Fluid line 16Fluid line 17Thermal insulation 20Partial quantity of the temperature control fluid

Claims

1. Device (1) for temperature control of an electric energy storage (5) of a motor vehicle, comprising an electric energy storage device (5), preferably a high-voltage energy storage battery; a fluid circuit (3) which can be thermally coupled and / or is coupled to the energy storage device (5) for tempering the energy storage device (5), wherein a tempering fluid can be supplied to and discharged from the energy storage device (5) through the fluid circuit; wherein the fluid circuit (3) comprises a pump device (10, 11) for transporting the temperature control fluid through the fluid circuit (3), a valve device (12), a cooling device (8) for cooling the temperature control fluid and a heating device (9) for heating the temperature control fluid, wherein the fluid circuit (3) comprises a sub-circuit (4) in which the heating device (9) is arranged; wherein the device (1) is configured to activate a heating operation of the heating device (9) when the motor vehicle is parked and when a predetermined heating condition is fulfilled, wherein a fluidic coupling of the partial circuit with the fluid circuit and a supply and discharge of temperature control fluid heated in the partial circuit to the electric energy storage (5) can be controlled by means of the valve device (12); wherein the device (1) is configured such that, when heating mode is activated in a first step (S3), to heat a predetermined partial quantity (20) of the temperature control fluid in the partial circuit (4) by the heating device (9), wherein the partial circuit (4) is fluidically separated from the remaining fluid circuit (3) and / or the energy storage device (5) by means of the valve device (12) and, in a second step (S4), the partial circuit (4) is fluidically connected to the energy storage device (5) by means of the valve device (12) and the heated predetermined partial quantity (20) is pumped to the energy storage device by means of the pump device (10, 11); wherein a) the energy storage (5) is thermally coupled to the fluid circuit (3) via a flow-through region (6) configured in a wall region, preferably in a base plate, of the energy storage (5), wherein the predetermined partial quantity (20) of the temperature control fluid which is heated in the first step corresponds to an absorption capacity of the flow-through region (6) of the energy storage, or is in the portion of 80 % - 200 %, further preferably 90 % - 130 % of the absorption capacity of the flow-through region (6); and / or b) the device is configured to control the valve device (12) and the pump device (10, 11) in the second step (S4) in such a way that the heated predetermined partial quantity (20) is pumped into the flow area (9) and remains there for a minimum period of time by stopping the fluid flow.

2. Device (1) according to claim 1, wherein the device is configured to perform several sequences for heating the energy storage (9) when the heating mode is activated, wherein each sequence comprises the first (S3) and second (S4) step, preferably such that sequential pulses of heated partial quantities (20) of the temperature control fluid are pumped to the energy storage (9) instead of a continuous temperature control fluid flow.

3. Device according to one of the preceding claims, wherein the partial circuit (4) comprises a holding capacity for tempering fluid which is less than 50 %, further preferably less than 30 % or less than 20 % of the holding capacity of the fluid circuit (3).

4. Device (1) according to one of the preceding claims, comprising an electrical sub-board network (7) of the motor vehicle, which is supplied and / or can be supplied with electrical voltage when the ignition is switched off and / or the battery main switch of the motor vehicle is pulled, preferably via the energy storage (6), wherein the heating device (9) is an electrically operated heating device arranged in the electrical sub-board network (7).

5. Device (1) according to one of the preceding claims, wherein the fluid circuit (3) comprises two lines (14, 15) connected in parallel, in which the heating device (9) and the cooling device (8) are arranged fluidically parallel to one another, wherein it is controllable by means of the valve device (12) via which of the lines (14, 15) connected in parallel a fluid flow can be supplied and / or is supplied to the energy storage device (9).

6. Device (1) according to claim 5, wherein the device (1) is configured, in the second step (S4), to fluidically decouple a line section (14) comprising the cooling device (8) from a line section (16) comprising the energy storage (6) by means of the valve device (12).

7. Device (1) according to any one of the preceding claims, wherein the predetermined heating condition is fulfilled if a temperature of the energy storage falls below a predetermined threshold value.

8. Device (1) according to one of the preceding claims, wherein the pump device (10, 11) comprises a first pump (10) arranged in the subcircuit for conveying the temperature control fluid within the subcircuit (4) and / or a second pump (11) arranged outside the subcircuit for conveying temperature control fluid to the energy storage (9).

9. Device (1) according to claim 8, wherein the device is configured to deactivate the first pump (10) only after a run-on period following deactivation of the heating device, in order to avoid cavitation effects.

10. Device (1) according to any of the preceding claims, a) wherein a thermal insulation (17) is provided on or adjacent to the heating device; and / or b) wherein the temperature control fluid is a glycol-water mixture; and / or c) wherein the energy storage device (5) is a lithium-ion accumulator energy storage device and / or a high-voltage energy storage device.

11. A motor vehicle, preferably a utility vehicle, such as a lorry or bus, comprising a device (1) according to one of the preceding claims.

12. Method for temperature control of an energy storage device (5) for electric energy of a motor vehicle, wherein the energy storage device (5) can be thermally coupled and / or is coupled to a fluid circuit (3) for temperature control of the energy storage device (5), wherein a temperature control fluid can be supplied to and discharged from the energy storage device (5) through the fluid circuit and wherein the fluid circuit (3) comprises a pump device (10,11) for transporting the temperature control fluid through the fluid circuit (3), a valve device (12), a cooling device (8) for cooling the temperature control fluid and a heating device (9) for heating the temperature control fluid, wherein the fluid circuit (3) comprises a subcircuit (4) in which the heating device (9) is arranged; wherein the method comprises: a) monitoring a predetermined heating condition when the vehicle is parked; and b) upon fulfilment of a predetermined heating condition, activation of a heating operation of the heating device (9), wherein a fluidic coupling of the partial circuit with the fluid circuit and a supply and discharge of temperature control fluid heated in the partial circuit to the electric energy storage (5) is controlled by means of the valve device (12); wherein a predetermined partial quantity (20) of the temperature control fluid in the partial circuit (4) is heated by the heating device (9) in a first step (S3) when heating mode is activated, wherein the partial circuit (4) is fluidically separated from the remaining fluid circuit (3) and / or the energy storage device (5) by means of the valve device (12) and in a second step (S4) the partial circuit (4) is fluidically connected to the energy storage device (5) by means of the valve device (12) and the heated predetermined partial quantity (20) is pumped to the energy storage device by means of the pump device (10, 11); wherein i the energy storage (5) is thermally coupled to the fluid circuit (3) via a flow-through region (6) configured in a wall region, preferably in a base plate, of the energy storage (5), wherein the predetermined partial quantity (20) of the temperature control fluid which is heated in the first step corresponds to an absorption capacity of the flow-through region (6) of the energy storage, or is in the portion of 80 % - 200 %, further preferably 90 % - 130 % of the absorption capacity of the flow-through region (6); and / or ii) in the second step (S4), the valve device (12) and the pump device (10, 11) are actuated in such a way that the heated predetermined partial quantity (20) is pumped into the flow area (9) and remains there for a minimum period of time by stopping the fluid flow.