Method and clamping device for clamping a vehicle battery

Abstract

Method for operating a clamping device (10) comprising a clamping unit (16) for clamping a vehicle battery (20) of a vehicle (30) by means of hydraulic fluid, a hydraulic tank (15) for storing the hydraulic fluid, a pump (12) for pumping the hydraulic fluid from the hydraulic tank (15), an electric motor (13) for driving the pump (12) by means of electrical energy, and a power transmission unit (14) operatively connected or connectable to a drive train of the vehicle (30) for driving the pump (12) by means of mechanical energy from the drive train, wherein a current and / or imminent operating state of the vehicle (30) is determined and the pump (12) for operating the clamping device (10) is driven by means of an electric motor (13) and / or by means of a power transmission unit (14), depending on the determined operating state of the vehicle (30).

Description

The present invention relates to a method and a clamping device for clamping a vehicle battery. The invention further relates to a computer program product for executing such a method by means of the clamping device, to a storage means on which such a computer program product is stored, and to a vehicle having a clamping device.In vehicles with an electric drive, vehicle drives are installed which change their volume over the service life of the vehicle battery during a charging process, during a discharging process and as a result of aging. The operating characteristic of lithium ion pouch cells is strongly dependent on external conditions, for example, because of their low mechanical stability. An external pressure that is as uniform as possible on the battery cells of the vehicle battery can be a decisive factor here for the performance, the service life and / or the structural stability of the vehicle battery or of a corresponding battery stack. A technical challenge with vehicle batteries is to compensate for a possible change in volume of up to 30% between the charged and discharged states of the vehicle battery.In order to always clamp the vehicle battery as uniformly as possible, methods and devices have been developed according to which the vehicle battery is clamped or pressurized depending on an operating state of the vehicle battery. German patent application DE 10 2009 028 986 A1 discloses, for example, a system for applying a pressure to a vehicle battery in order to reduce functional impairment that occurs due to different battery states of charge. The bracing of the vehicle battery is generally realized via a hydraulic system in which a hydraulically operated clamping unit braces the vehicle battery. The pressure for operating the clamping unit is usually generated via a hydraulic pump of the system. Hydraulic pumps of the generic type have a certain energy requirement for building up the desired pressure, which is taken from the vehicle battery. Energy taken from the vehicle battery for the bracing can consequently no longer be made available for driving the vehicle, as a result of which, for example, the maximum possible range of the vehicle is reduced. In other words, the gravimetric energy density of the vehicle battery is reduced in this way.It is an object of the present invention to at least partially take account of the above-described problems. In particular, it is an object of the present invention to clamp a vehicle battery as energy-efficiently as possible and nevertheless reliably.The above object is achieved by the claims. In particular, the above object is achieved by the method according to claim 1, the clamping device according to claim 10, the computer program product according to claim 11, the storage means according to claim 12 and the vehicle according to claim 13. Further advantages of the invention are evident from the dependent claims, the description and the figures. Features described in connection with the method naturally also apply in connection with the clamping device according to the invention, the computer program product according to the invention, the storage means according to the invention, the vehicle according to the invention and vice versa, so that with regard to the disclosure reference to the individual aspects of the invention is and / or can always be made mutually.According to a first aspect of the present invention, a method for operating a clamping device is proposed. The clamping device has a clamping unit for clamping a vehicle battery of a vehicle by means of hydraulic fluid, a hydraulic tank for storing the hydraulic fluid, a pump for pumping the hydraulic fluid from the hydraulic tank, an electric motor for driving the pump by means of electrical energy, and a force transmission unit, which is or can be operatively connected to a drive train of the vehicle, for driving the pump by means of mechanical energy from the drive train. To carry out the method, a current and / or imminent operating state of the vehicle is determined. For operating the clamping device, the pump is driven, depending on the determined operating state of the vehicle, by means of an electric motor and / or by means of a force transmission unit, and thus in particular by means of electrical energy from the vehicle battery and / or by means of mechanical energy from the drive train.Within the scope of the present invention, it has been recognized that the kinetic energy of the vehicle can be used for operating the clamping device and in particular for operating the pump. This means that electrical energy from the vehicle battery no longer has to be used (will be) exclusively for actuating the clamping unit according to the method, since, depending on the current and / or predicted operating state of the vehicle, the kinetic energy of the vehicle and in particular mechanical energy from the drive train of the vehicle is or can also be used. The electrical energy consumption of the clamping device or for clamping the vehicle battery can thus be reduced accordingly. At the same time, the operation of the clamping device can be carried out reliably and effectively without change. Consequently, the gravimetric energy density of the vehicle battery can also be increased.By driving or actuating the pump depending on the ascertained current and / or imminent operating state of the vehicle, strategic regulation of the hydraulic pressure in the clamping device is made possible. If the force transmission unit is used to drive the pump by means of directly used mechanical energy, at least a part of the efficiency chain between the electric motor and the power electronics can be avoided. That is, an initial conversion of the mechanical energy from the drive train into electrical energy of the vehicle battery can be dispensed with, since the energy is used directly for the pump.The pump is to be understood in particular as a hydraulic pump. The pump can also be understood, quite generally, as a means for actuating the clamping unit, in particular by means of the hydraulic fluid, so that the clamping unit clamps or pressurizes the vehicle battery. The pump can be connected via a clutch, in particular a magnetic clutch, to a shaft of the drive train and / or a transmission of the drive train, or can be connected for establishing the operative connection. The force transmission unit can therefore have a shaft and / or a shaft stub which can be brought into operative connection with the pump by means of the coupling. The kinetic energy of the vehicle can thus be converted into hydraulic pressure.If the vehicle is stationary, the pump for operating the clamping device or for generating the desired pressure on the vehicle battery is preferably driven by means of an electric motor. Once the vehicle is moving and other conditions are met, the pump may be powered from the powertrain using mechanical energy. According to the method, the clamping unit can be actuated or actuated directly or indirectly by hydraulic fluid and the pump can be actuated or operated by means of an electric motor and / or by means of a force transmission unit depending on the operating state of the vehicle, whereby hydraulic fluid is pumped to the clamping unit by means of an electric motor and / or by means of a force transmission unit in order to clamp the vehicle battery.The term "bracing" is understood to mean a generic pressure application of the vehicle battery in order to compensate changes in size of the vehicle battery or always to subject the vehicle battery to the same pressure as possible even during the change in size. The operating state also comprises a driving state of the vehicle and, for example, also environmental conditions which can be used and / or taken into account for ascertaining an imminent operating state of the vehicle. If it is detected, for example, on the basis of a travel route in a navigation system of the vehicle that the vehicle will travel downhill at a current speed of 100 km / h at a distance of 2,000 meters, a corresponding operating state can be predicted or determined, in which the vehicle will be located in approximately one minute and 12 seconds. When ascertaining the current and / or imminent operating state of the vehicle, a current operating state, an imminent operating state, a current driving state, an imminent driving state, current ambient conditions and / or imminent ambient conditions (for example on the basis of a weather forecast) can therefore be understood. The operating state of the vehicle can also be understood to mean the operating state of at least one functional component of the vehicle, optionally the vehicle battery-independent operating state of the vehicle and / or at least one functional component of the vehicle. Thus, the operating state of the vehicle can be understood, for example, as a function of the operating state of a crash sensor of the vehicle, so that the pump is driven by means of an electric motor and / or by means of a force transmission unit as a function of the ascertained operating state of the crash sensor, i.e., for example, as a function of whether a crash has been detected or not. If a crash has been detected, the pump is preferably driven by means of an electric motor, since the drive train may no longer be available as a supplier of mechanical energy and nevertheless the safeest possible operation or at least safe storage of the vehicle battery is to be ensured.Operating the clamping device can be understood to mean that the clamping device is actuated for clamping or pressurizing the vehicle battery. The vehicle battery can be understood to mean a traction battery and / or high-voltage battery of the vehicle. For applying the desired pressure to the vehicle battery, the clamping device can have at least one hydraulic cylinder, wherein the required hydraulic pressure can be provided by means of the pump or at least one pump. The electric motor is preferably supplied with electrical energy by the vehicle battery. That is, the electric motor is preferably operated with electric power from the vehicle battery.According to a further embodiment of the present invention, it is possible that the clamping device has an accumulator and the pump is configured to charge the accumulator by means of the hydraulic fluid, wherein the pump is driven by means of an electric motor and / or by means of a force transmission unit to charge the accumulator, depending on the operating state of the vehicle determined. That is, the pressure in the pressure accumulator can be set to a predefined or pre-definable value depending on the ascertained current and / or imminent operating state. In other words, depending on the driving state, it is possible to decide which pressure is held in the pressure accumulator and / or to which value the pressure in the pressure accumulator is to be set. The pressure accumulator can thus preferably be charged by means of the force transmission unit during a vehicle deceleration and / or by braking of the vehicle and thus serve as a recuperation accumulator. The pressure accumulator is preferably charged by means of the force transmission unit as far as possible at every negative acceleration or at every deceleration of the vehicle, so that a degree of recuperation which is as high as possible is achieved. Alternatively or additionally, it is possible for the pressure accumulator to be charged or at least partially charged, for example, by means of the electric motor in driving states in which a particularly high internal noise or an internal noise above a predefined reference value is induced in the vehicle, as a result of which it is possible to prevent persons in the vehicle from acoustically perceiving the pump and / or the electric motor. In this case, it may be advantageous in terms of energy not to keep the pressure in the pressure accumulator constant at the currently required level, but instead, for example depending on one or at least one imminent operating state of the vehicle, to keep it variable in a predefined or predeterminable range, for example alternately in the manner of a sawtooth profile. The pressure build-up in the pressure accumulator can thus be carried out taking into account an energy consumption of the pump and / or of the clamping device and taking into account a noise emission value of the pump and / or of the clamping device. A bubble accumulator, a piston accumulator and / or a diaphragm accumulator can be used as the pressure accumulator for this purpose. The pressure accumulator can therefore be understood to mean a hydraulic pressure accumulator. For charging the pressure accumulator, a pressure value in the pressure accumulator can be determined, wherein the pressure accumulator is charged and / or even further charged depending on the determined pressure value. Charging the pressure accumulator can be understood to mean filling the pressure accumulator with hydraulic fluid and / or building up a pressure in the pressure accumulator. To carry out the method, the clamping device and / or various functional components of the clamping device, such as the pump, the electric motor, the force transmission unit, the hydraulic tank, the pressure accumulator and / or further components for ascertaining the current and / or imminent operating state of the vehicle, can be in signal communication with a computer, in particular within a vehicle control device which is configured to carry out the method. In addition, different functional components of the clamping device can be connected to one another in terms of signals.It is also possible that in a method according to the present invention a pressure value is determined in the pressure accumulator and for determining the operating state it is determined whether a negative acceleration of the vehicle, a downhill travel and / or a travel speed which is higher than a predefined travel speed are present, wherein the pump, depending on the determined pressure value, is mechanically driven by means of the force transmission unit for charging the pressure accumulator when a negative acceleration of the vehicle, a downhill travel and / or a travel speed which is higher than the predefined travel speed are determined. The vehicle battery can thus be saved as an energy supplier for bracing the vehicle battery in a correspondingly large number of different driving situations or operating states of the vehicle. Instead of the electrical energy, kinetic energy of the vehicle that is already available can be used to charge the pressure accumulator and thus store energy for bracing the vehicle battery. If it is determined, for example, that the pressure value in the pressure accumulator is below a maximum permissible pressure value and the vehicle is decelerated or accelerated negatively, the kinetic energy of the vehicle or at least a part of this energy can be stored hydraulically in the pressure accumulator via the force transmission unit and by means of the pump which is operated by the force transmission unit.Furthermore, it is possible that in a method according to the invention a pressure value is determined in the pressure accumulator and it is determined for determining the operating state whether the vehicle battery is electrically charged at a charging station, wherein the pump, depending on the determined pressure value, is electrically driven by means of the electric motor for charging the pressure accumulator if it is determined that the vehicle battery is electrically charged at a charging station. That is, it is determined or established that the vehicle battery is electrically charged at a charging station and that the pressure accumulator is not yet fully charged, said accumulator is charged by means of electrical energy from the charging station or by the electric motor, which converts said energy into mechanical energy. This allows the charging operation to be configured efficiently and vehicle components to be saved. If the pressure accumulator has already been fully charged, no charging process takes place, of course.According to a further variant of a method according to the invention, a pressure value in the pressure accumulator and, for ascertaining the operating state, a current travel speed of the vehicle can be ascertained, wherein the ascertained travel speed is compared with a reference travel speed and the pressure accumulator, depending on the ascertained pressure value, is charged to a minimum pressure value which is below a maximum pressure value at which the pressure accumulator is fully charged if the ascertained current travel speed is lower than the reference travel speed. In other words, it is determined or established that the determined travel speed is lower than the predefined reference travel speed because the vehicle travels through a locality, for example, and that the pressure accumulator is not yet fully charged, said accumulator can be charged or pressurized to the minimum pressure value by means of electrical energy from the vehicle battery or by the electric motor which converts said energy into mechanical energy. This means that the pressure accumulator is only charged to a necessary minimum pressure value in this case in order to avoid the driver and / or persons in the vehicle being disturbed, or only as little as possible, by noises from the electric motor, the pump and / or from further functional components of the clamping device. Further preconditions for operation by means of an electric motor at low travel speed could be that the vehicle is currently not braking or negatively accelerating and / or is currently or imminent not travelling downhill. If the vehicle travels down a curved mountain road at low speed, for example, pump operation by means of a force transmission unit would be more appropriate. The operating parameters to be taken into account for this can be input and / or changed in a vehicle control device, for example manually by means of an input unit for the driver and / or a service worker.Furthermore, it is possible that in a method according to the present invention for determining the operating state, a current and / or imminent travel speed of the vehicle is determined and the pump is driven by means of an electric motor and / or by means of a force transmission unit for operating the clamping device, depending on the determined travel speed. This also allows energy-efficient operation of the clamping device to be achieved. If it is determined, for example, that the vehicle is travelling at a high travel speed, the pump for bracing the vehicle battery and / or for charging the pressure accumulator can be operated preferably by means of the force transmission unit, in particular exclusively by means of the force transmission unit. If it is determined that the vehicle is travelling at a low travel speed, the pump for bracing the vehicle battery and / or for charging the pressure accumulator can preferably be operated by means of the electric motor. An imminent driving speed can be determined in particular by means of navigation data from a navigation device, for example by virtue of imminent freeway travel being determined and / or detected. Accordingly, an imminent operating and / or driving state of the vehicle can also be determined.In a method according to the present invention, it is also possible that navigation data of a navigation device of the vehicle are ascertained for ascertaining the operating state, in particular the imminent operating state, and the pump is driven by means of an electric motor and / or by means of a force transmission unit depending on the ascertained navigation data for operating the clamping device. This also allows energy-efficient operation of the clamping device to be achieved. If it is determined, for example, that the vehicle is driving down a mountain road in the foreseeable future, it is possible to wait until then for the pressure accumulator to be charged and / or for the vehicle battery to be braced. As soon as the vehicle brakes or accelerates negatively on the gradient of the mountain road, the kinetic energy of the vehicle now present can be used by means of a force transmission unit, in particular exclusively by means of a force transmission unit, for bracing the vehicle battery and / or for charging the pressure accumulator, and the pump can be operated accordingly. If it is established or determined by means of the navigation data that the vehicle is expected to travel for a long time on level ground at a relatively low speed, while the pressure value in the pressure accumulator is already relatively low and / or the bracing force on the vehicle battery is too low or lower than a predefined value, the pump is driven using electrical energy from the vehicle battery by means of an electric motor, in particular exclusively by means of an electric motor, in order to apply the desired bracing force to the vehicle battery and / or to raise the pressure in the pressure accumulator to a desired value, for example the above-described minimum pressure value.In addition, in a method according to the present invention, for ascertaining the operating state, ambient conditions in an environment of the vehicle and / or a battery state of the vehicle battery can be ascertained, wherein the pump is driven by means of an electric motor and / or by means of a force transmission unit depending on the ascertained ambient conditions and / or depending on the ascertained battery state for operating the clamping device. Taking into account the ambient conditions and / or the battery state, it is likewise possible to operate the clamping device in a particularly energy-efficient manner. If it is determined that the ambient temperature is low or will fall into a mountain as a result of imminent travel and / or through an imminent snow storm over a longer period of time, as a result of which it is possible for a corresponding pressure requirement to be produced at the vehicle battery, the pressure accumulator can already be charged as maximally as possible beforehand by means of a force transmission unit and / or by means of an electric motor. The clamping device can thus be operated accordingly in a predictive and strategic manner. The battery state can be understood to mean a state of charge (SOC) and / or a state of health (SOH) of the vehicle battery. For example, the pump can be operated preferably by means of the force transmission unit or by means of mechanical energy and in particular exclusively by means of the force transmission unit if it is determined that the state of charge of the vehicle battery or a corresponding charge value is below a predefined or pre-definable reference charge value.According to a further aspect of the present invention, a clamping device for carrying out a method as described above is proposed. The clamping device has a clamping unit for clamping a vehicle battery of a vehicle by means of hydraulic fluid, a hydraulic tank for storing the hydraulic fluid and a pump for pumping the hydraulic fluid from the hydraulic tank and in particular for charging a pressure accumulator and / or for clamping the vehicle battery. The clamping device further comprises an electric motor for driving the pump by means of electrical energy and a force transmission unit, which can be operatively connected to a drive train of the vehicle, for driving the pump by means of mechanical energy from the drive train. Thus, the clamping device according to the invention provides the same advantages as have been described in detail with reference to the method according to the invention. The clamping device can be understood to mean the essential component of a system for carrying out a method according to the invention. The pump is in particular designed in the form of a hydraulic pump and the pressure accumulator can be configured accordingly as a hydraulic accumulator, in particular in the form of a diaphragm accumulator. The clamping device can have a computer, in particular in the form of a vehicle control device and / or as part of the vehicle control device, wherein the computer can be configured to determine a current and / or imminent operating state of the vehicle and to drive and / or actuate the pump for operating the clamping device, depending on the determined operating state of the vehicle, by means of an electric motor and / or by means of a force transmission unit. For this purpose, within the scope of the invention, a computer program product is also provided which comprises instructions which, when the computer program product is executed by a computer, cause the computer program product to execute a method as described above with the described clamping device. Although the clamping device is preferably configured for use in a vehicle, it can also be used in other systems in which a battery, in particular in the form of a high-voltage battery, has to be pressurized and various energy sources are available.The clamping device can have a determination unit for determining the current and / or imminent operating state of the vehicle and for determining the information required for this purpose, such as, for example, the pressure in the pressure accumulator, the travel speed, the presence of a negative acceleration of the vehicle, the downhill travel of the vehicle, the charging and / or health state of the vehicle battery and / or the environmental conditions in the environment of the vehicle. For this purpose, the determination unit can have suitable arithmetic units, sensor elements and / or comparison units.The computer program product may be implemented as computer readable instruction code in any suitable programming language and / or machine language such as JAVA, C++, C#, and / or Python. The computer program product can be stored on a computer-readable storage medium such as a data disk, a removable drive, a volatile or non-volatile memory, or a built-in memory / processor. The instruction code may program a computer or other programmable devices such as a vehicle controller to perform the desired functions. Further, the computer program product may be provided and / or reside on a network such as the Internet from which it may be downloaded by a user as needed. The computer program product can be and / or be realized both by means of software and by means of one or more special electronic circuits, that is to say in hardware or in any hybrid form, that is to say by means of software components and hardware components.According to a further aspect of the present invention, a computer-readable storage means is proposed on which a computer program product as described above is stored. The storage means is preferably configured in the form of a non-volatile storage means. Furthermore, a vehicle is provided having a vehicle battery, a clamping device as described above and a computer, wherein the computer and the clamping device are configured to carry out the described method. In such a vehicle, the clamping device is thus configured such that the pump is driven by means of an electric motor and / or by means of a force transmission unit, depending on the current and / or imminent operating state of the vehicle, and / or charges the pressure accumulator by means of an electric motor and / or force transmission unit, depending on the current and / or imminent operating state of the vehicle. The vehicle is preferably designed in the form of a road vehicle, in particular in the form of a passenger car or truck, but can also be designed as a watercraft, aircraft, rail vehicle or robot.Further measures which improve the invention will become apparent from the following description of various exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages emerging from the claims, the description or the figures, including structural details and spatial arrangements, can be essential to the invention both alone and in the various combinations.They show in each case schematically: FIG. 1 is a diagram for explaining a lockup device of a vehicle according to a preferred embodiment of the present invention, FIG. 2 shows a detail of the clamping device shown in FIG. 1, FIG. 3 shows a storage means with a computer program product stored thereon, and FIG. 4 shows a flow chart for explaining a method according to the invention.Elements with the same function and mode of operation are provided with the same reference numerals in each of the figures.FIG. 1 shows a clamping device 10 for strategic clamping or pressurization of a vehicle battery 20 of a vehicle 30 according to a preferred embodiment. The clamping device 10 has a clamping unit 16 for clamping the vehicle battery 20 by means of hydraulic fluid. That is to say that battery cells of the vehicle battery 20 in a battery housing of the vehicle battery 20 can be pressurized in a targeted manner, in particular depending on a battery state of the vehicle battery 20, by means of the clamping unit 16. The clamping device 10 further comprises a hydraulic tank 15 for storing the hydraulic fluid and a pump 12 for pumping the hydraulic fluid from the hydraulic tank 15 to the clamping unit 16 and to a pressure accumulator 11 of the clamping device 10. Furthermore, the clamping device 10 has an electric motor 13 for driving the pump 12 by means of electrical energy, in particular from the vehicle battery 20. In addition, the clamping device 10 has a force transmission unit 14 in the form of a shaft stub, which can be operatively connected to a drive train of the vehicle 30, said transmission unit being shown in FIG. 2 for driving the pump 12 by means of mechanical energy from the drive train. For switching between an operation in which the pump 12 is operated to operate the clamping unit 16 and an operation in which the pump 12 is operated to charge the accumulator 11, the clamping device 10 includes a proportional valve 17, a pressure limiting valve 18 and a pressure regulating valve 19.For operating the clamping device 10, it also has a computer 50 in the form of a vehicle control device, on which a correspondingly configured computer program product 40 is installed. FIG. 2 shows a detail of the clamping device 10 shown in FIG. 1. More precisely, FIG. 2 shows the pump 12 to which the electric motor 13 and the force transmission unit 14 for driving the pump 12 can be coupled in order to charge the pressure accumulator 11. FIG. 3 shows a non-transitory and computer readable storage means 60 having a computer program product 40 stored thereon.With reference to FIG. 4, a method for operating the clamping device 10 shown in FIGS. 1 and 2 will be explained below. According to a first step S 1, a current and an imminent operating state of the vehicle 30 are first ascertained using suitable arithmetic units and sensor elements. In a second step S 2, depending on the ascertained current and imminent operating state of the vehicle 30, the pump 12 is now driven by means of the electric motor 13 and / or by means of the force transmission unit 14, in order thereby to operate the clamping device 10 accordingly. Depending on various influencing parameters, the clamping device 10 can therefore be operated strategicly or differently to the effect that electrical energy and / or mechanical energy or kinetic energy of the vehicle 30 are used by means of the electric motor 13 and / or by means of the force transmission unit 14 for the operation of the pump 12 or a corresponding delivery unit for delivering the hydraulic fluid.Thus, the pump 12 can be driven by means of an electric motor 13 and / or by means of a force transmission unit 14 for charging the pressure accumulator 11, depending on the operating state of the vehicle 30 determined. Furthermore, depending on a determined pressure value in the pressure accumulator 11, the pump 12 can be mechanically driven by means of the force transmission unit 14 for charging the pressure accumulator 11 if a negative acceleration of the vehicle 30, a downhill travel and / or a travel speed which is higher than the predefined travel speed are determined. In addition, it is possible that the pump 12, depending on the ascertained pressure value, is electrically driven for charging the pressure accumulator 11 by means of the electric motor 13 if it is ascertained that the vehicle battery 20 is electrically charged at a charging station. For ascertaining the operating state, a current travel speed of the vehicle 30 can be ascertained, wherein the ascertained travel speed is compared with a reference travel speed and the pressure accumulator 11, depending on the ascertained pressure value, is charged to a minimum pressure value which is below a maximum pressure value at which the pressure accumulator 11 is completely charged, if the ascertained current travel speed is lower than the reference travel speed. That is, for example, the vehicle 30 is traveling through an orthosis at a low speed below the reference traveling speed, and if no mechanical energy is to be used to charge the pressure accumulator 11, the pressure accumulator 11 can be charged by means of electrical energy from the vehicle battery 20 and using the electric motor 13, but only to the minimum required minimum pressure value.In the context of the method, it is also possible that, in order to ascertain the operating state, a current and / or imminent driving speed of the vehicle 30, navigation data of a navigation device of the vehicle 30, ambient conditions in the environment of the vehicle 30 and / or a battery state of the vehicle battery 20 are ascertained, and the pump 12 is driven accordingly as a function of the ascertained driving speed, of the ascertained navigation data, of the ascertained ambient conditions and / or of the ascertained battery state by means of an electric motor 13 and / or by means of a force transmission unit 14, in order to operate the clamping device 10 for clamping the vehicle battery 20.In addition to the embodiments shown, the invention allows further design principles. That is, the invention should not be considered limited to the exemplary embodiments explained with reference to the figures.List of reference characters10 Clamping device 11 Pressure accumulator 12 Pump 13 Electric motor 14 Force transmission unit 15 Hydraulic tank 16 Clamping unit 17 Proportional valve 18 Pressure limiting valve 19 Pressure regulating valve 20 Vehicle battery 30 Vehicle 40 Computer program product 50 Computer 60 Storage means

Claims

Method for operating a clamping device (10), which has a clamping unit (16) for clamping a vehicle battery (20) of a vehicle (30) by means of hydraulic fluid, a hydraulic tank (15) for storing the hydraulic fluid, a pump (12) for pumping the hydraulic fluid from the hydraulic tank (15), an electric motor (13) for driving the pump (12) by means of electrical energy and a force transmission unit (14), which is or can be operatively connected to a drive train of the vehicle (30), for driving the pump (12) by means of mechanical energy from the drive train, wherein a current and / or imminent operating state of the vehicle (30) is determined and the pump (12) for operating the clamping device (10) is driven by means of electric motor (13) and / or by means of force transmission unit (14), depending on the determined operating state of the vehicle (30).Method according to Claim 1, characterized in that the clamping device (10) has a pressure accumulator (11), and the pump (12) is configured for charging the pressure accumulator (11) by means of the hydraulic fluid, wherein the pump (12) is driven by means of an electric motor (13) and / or by means of a force transmission unit (14) for charging the pressure accumulator (11), depending on the operating state of the vehicle (30) determined.Method according to Claim 2, characterized in that a pressure value is determined in the pressure accumulator (11), and for determining the operating state it is determined whether there is a negative acceleration of the vehicle (30), a downhill travel and / or a travel speed which is higher than a predefined travel speed, wherein the pump (12), depending on the determined pressure value, is mechanically driven by means of the force transmission unit (14) for charging the pressure accumulator (11) if a negative acceleration of the vehicle (30), a downhill travel and / or a travel speed which is higher than the predefined travel speed are determined.Method according to one of Claims 2 to 3, characterized in that a pressure value is determined in the pressure accumulator (11), and it is determined for determining the operating state whether the vehicle battery (20) is electrically charged at a charging station, wherein the pump (12), depending on the determined pressure value, is electrically driven by means of the electric motor (13) for charging the pressure accumulator (11) if it is determined that the vehicle battery (20) is electrically charged at a charging station.Method according to one of Claims 2 to 4, characterized in that a pressure value is determined in the pressure accumulator (11), and a current travel speed of the vehicle (30) is determined for determining the operating state, wherein the determined travel speed is compared with a reference travel speed and the pressure accumulator (11), depending on the determined pressure value, is charged to a minimum pressure value which is below a maximum pressure value at which the pressure accumulator (11) is fully charged if the determined current travel speed is lower than the reference travel speed.Method according to one of the preceding claims, characterized in that, in order to determine the operating state, a current and / or imminent travel speed of the vehicle (30) is determined and the pump (12) is driven by means of an electric motor (13) and / or by means of a force transmission unit (14) in dependence on the determined travel speed in order to operate the clamping device (10).Method according to one of the preceding claims, characterized in that navigation data of a navigation device of the vehicle (30) are determined in order to determine the operating state, and the pump (12) is driven by means of an electric motor (13) and / or by means of a force transmission unit (14) in dependence on the navigation data determined in order to operate the clamping device (10).Method according to one of the preceding claims, characterized in that, in order to determine the operating state, ambient conditions in the environment of the vehicle (30) are determined and the pump (12) is driven by means of an electric motor (13) and / or by means of a force transmission unit (14) in dependence on the determined ambient conditions in order to operate the clamping device (10).Method according to one of the preceding claims, characterized in that a battery state of the vehicle battery (20) is determined in order to determine the operating state, and the pump (12) is driven by means of an electric motor (13) and / or by means of a force transmission unit (14) in dependence on the determined battery state in order to operate the clamping device (10).Clamping device (10) for carrying out a method according to one of the preceding claims, having a clamping unit (16) for clamping a vehicle battery (20) of a vehicle (30) by means of hydraulic fluid, a hydraulic tank (15) for storing the hydraulic fluid, a pump (12) for pumping the hydraulic fluid from the hydraulic tank (15), an electric motor (13) for driving the pump (12) by means of electrical energy, and a force transmission unit (14), which can be operatively connected to a drive train of the vehicle (30), for driving the pump (12) by means of mechanical energy from the drive train.A computer program product (40) comprising instructions which, when the computer program product (40) is executed by a computer (50), cause the computer program product to carry out the method according to any one of the preceding claims with a clamping device (10) according to claim 10.A computer readable storage means (60) having stored thereon a computer program product (40) according to claim 11.A vehicle (30) comprising a vehicle battery (20), a chuck (10) according to claim 10 and a computer (50), wherein the computer (50) and the chuck (10) are configured to perform a method according to any one of claims 1 to 9.

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