Energy storage vehicle interface for a forklift truck

Abstract

Method for operating a forklift truck with • at least one electrical energy storage device, • at least one electrical appliance and • an energy storage vehicle interface comprising an energy storage terminal, a first consumer terminal and a preferably rewritable data storage device on which energy storage information about the energy storage device is stored, • wherein the energy storage device is connected to the energy storage terminal, at least one consumer is connected to the first consumer terminal, the first consumer terminal may be open or closed, and the energy storage terminal is electrically connected to the first consumer terminal when the first consumer terminal is closed, comprehensively the steps: • Measuring an energy storage voltage applied to the energy storage terminal and preferably an energy storage current flowing through the energy storage terminal, • Determining an energy storage state parameter using the energy storage information and the energy storage voltage, and preferably the energy storage current, • Opening of the first consumer terminal depending on the energy storage state parameter, • preferably charging the energy storage device and • Re-closing of the first consumer terminal depending on the energy storage state parameter.

Description

[0001] Industrial trucks can be equipped with various electrical energy storage devices. While lead-acid batteries were commonly used in the past, more modern battery types, such as lithium-ion batteries, are increasingly being employed. Older batteries, in particular, often lack features that allow monitoring of their charge level and the transmission of a corresponding signal to the truck's control system. Newer batteries, on the other hand, are frequently equipped with a battery management system that can transmit relevant information to the truck's control system. This presents a challenge in the development of industrial trucks, as the control system and other energy storage devices must be individually adapted to the specific energy storage system.

[0002] Problems also arise during operation when using different types of energy storage. To prevent deep discharge of the energy storage system, the connected devices must be switched off in a timely manner. If the energy storage system has a battery management system that transmits relevant information about the remaining charge to the forklift's control unit, the forklift can ensure timely shutdown. This is not readily possible with energy storage systems without a battery management system.

[0003] This leads to the objective underlying the present invention, which is to simplify the development and operation of a forklift truck when using different types of energy storage.

[0004] The problem is solved by a method according to claim 1, an energy storage vehicle interface according to claim 9, a forklift truck according to claim 14, and a fleet of forklift trucks according to claim 21. The dependent claims and the following description present advantageous embodiments. Where the description explicitly refers to claims, this shall also include the corresponding further advantageous embodiments presented in the description. It should also be possible to use embodiments of the energy storage vehicle interface, the forklift truck, and the fleet of forklift trucks in carrying out the method.

[0005] The inventive method according to claim 1 serves to operate a forklift truck with at least one electrical energy storage device, at least one electrical consumer, and an energy storage vehicle interface. The energy storage vehicle interface comprises an energy storage terminal, a first consumer terminal, and preferably a rewritable data storage device on which energy storage information about the energy storage device is stored. The energy storage device is connected to the energy storage terminal, the at least one consumer is connected to the first consumer terminal, the first consumer terminal can be open or closed, and the energy storage terminal is electrically connected to the first consumer terminal when the first consumer terminal is closed.

[0006] In one step of the method, the energy storage voltage applied to the energy storage terminal and, preferably, the energy storage current flowing through the energy storage terminal are measured. An energy storage state parameter is determined in a further step of the method using the energy storage information, the energy storage voltage, and, preferably, the energy storage current. In additional steps, the first load terminal is opened depending on the energy storage state parameter, preferably the energy storage device is charged, and the first load terminal is closed again depending on the energy storage state parameter. The steps can be performed in the described sequence.

[0007] According to the procedure, the load terminal is opened or closed depending on the energy storage state parameter. When the load terminal is open, it prevents the at least one electrical load connected to it from drawing any further current. This prevents the energy storage system from being deeply discharged by the current consumption of the at least one electrical load.

[0008] To determine the energy storage state parameter, at least the energy storage voltage and the energy storage information are used. The energy storage voltage is applied to the energy storage terminal of the energy storage vehicle interface, in whose data storage the energy storage information is stored. The energy storage vehicle interface is a component that is separate from the electrical energy storage device. "Separate" can mean that there is a physical and / or electrical separation. A physical separation can exist, in particular, if the energy storage vehicle interface is not integrated into a housing of the energy storage device, but rather into a part of the rest of the vehicle system.Electrical isolation, for example in the form of galvanic isolation, can occur particularly when the energy storage vehicle interface is located downstream of the energy storage device's terminals in the direction of current flow. The energy storage vehicle interface is therefore a component of the industrial truck, but not of the energy storage device itself.

[0009] In this context, it is particularly noteworthy that the energy storage information is stored on the data storage of the energy storage vehicle interface and only needs to be configured once the specific energy storage system to be used in the forklift truck has been determined. This allows the forklift truck to be designed, maintained, and / or operated independently of the energy storage system used. The energy storage vehicle interface thus ensures that the forklift truck can be operated modularly with various energy storage systems based on different energy storage technologies, such as lead-acid, fuel cell, or lithium-ion technology. In summary, this method ensures that the type of energy storage system used is irrelevant for a forklift truck equipped with an energy storage vehicle interface.The energy storage vehicle interface belonging to the industrial truck ensures that deep discharge is always avoided and that the consumers connected to the energy storage vehicle interface can be operated in the same way.

[0010] According to one embodiment of the method, the energy storage state indicator reflects a state of charge of the energy storage device, and the first consumer terminal is opened when the state of charge is less than a minimum standby residual charge value, and / or the first consumer terminal is closed when the state of charge is greater than a minimum standby charge value.

[0011] Opening the consumer terminal when the charge level is lower than a minimum standby residual charge value prevents the continued consumption of electricity by at least one electrical consumer when the residual charge of the energy storage device is too low, which could lead to deep discharge.

[0012] On the other hand, the first load terminal is closed again when the charge level reaches a minimum standby charge value. If the battery has been discharged to the point where the load terminal had to be opened, it will be closed again as soon as the battery is charged to the minimum standby charge value. Then, the electrical device, for example, to maintain standby functions such as powering up control units, can once again draw power from the energy storage device.

[0013] According to one embodiment of the method, the energy storage state indicator reflects a time period since the last use of the energy storage device, and the first load terminal is opened when this time period exceeds a standby time. Preferably, the time period is measured as a difference between the time of the last use and a present time, wherein, at the time of the last use, the measured energy storage current last corresponded to at least one current consumption of the first load connected to the first load terminal in its switched-on state.

[0014] Opening the first load terminal after the standby period prevents deep discharge if the forklift or the at least one electrical device connected to the first load terminal has not been used for an extended period and is therefore unlikely to be used again in the foreseeable future. It is advantageous that opening the first load terminal after the standby period occurs within the energy storage interface. This ensures that control, particularly regarding deep discharge protection, remains with the forklift via the energy storage interface.

[0015] According to one embodiment of the method, the industrial truck has at least two electrical consumers. Furthermore, the energy storage vehicle interface has a second consumer terminal, which can be open or closed. When the second consumer terminal is closed, the energy storage terminal is electrically connected to the second consumer terminal. At least one consumer is also connected to the second consumer terminal.

[0016] In additional steps of the process, the second load terminal is opened and closed depending on the energy storage state parameter. The opening and closing of the second load terminal can occur independently of the opening and closing of the first load terminal. This allows different types of electrical loads to be connected to the first or second load terminal, respectively. Depending on the functions performed by these two types of electrical loads and their power consumption, they can be connected to either the first or the second load terminal.

[0017] For example, high-power consumers can be connected to the first terminal, while lower-power consumers can be connected to the second terminal. The first terminal can then be opened after use, disconnecting high-power consumers from the energy storage system early and effectively preventing deep discharge. Meanwhile, the second terminal allows certain functions to remain available, such as the ability to reactivate the first terminal without direct operator intervention.

[0018] According to one embodiment of the method, the second load terminal is opened when the state of charge is less than a low-standby maximum discharge value, and / or the second load terminal is closed when the state of charge is greater than a low-standby minimum charge value. The low-standby maximum discharge value and / or the low-standby minimum charge value can be less than the standby maximum discharge value or the standby minimum charge value, respectively. In this case, the second electrical load can still be used even if the energy storage device is more discharged than the standby minimum residual charge value, or even used again when the energy storage device is even less charged than the standby minimum charge value.The at least one second electrical consumer can therefore be an electrical consumer that has a lower power consumption than the at least one electrical consumer connected to the first consumer terminal and can still be driven even if operating the at least one electrical consumer connected to the first consumer terminal would pose a risk of deep discharge.

[0019] According to one embodiment of the method, the energy storage vehicle interface has a communication interface. In an additional step of the method, a communication signal is provided that includes the energy storage state parameter. Preferably, the communication signal also includes an indication that the state of charge has fallen below a residual charge warning value, and / or an indication that the time since the last use has exceeded a standby activation time warning value.

[0020] The communication signal can be tapped from the at least one electrical device connected to the communication interface and used to execute a corresponding action. This could, for example, be the automatic switching off of the at least one electrical device connected to the first terminal before the terminal is opened. Using the communication signal allows for more flexible operation of the electrical devices connected to the energy storage vehicle interface.

[0021] Preferably, in an additional process step, the at least one electrical consumer connected to the first consumer terminal is put into a standby state before it is switched off and then the first consumer terminal is opened.

[0022] Furthermore, the at least one electrical load connected to the second load terminal can preferably be designed to switch on a switched-off electrical load connected to the first load terminal. If, following a charging process, the energy storage device is charged sufficiently that its state of charge exceeds the minimum standby charge level, the at least one electrical load connected to the first load terminal can be automatically switched on in this way by the at least one electrical load connected to the second load terminal. As explained above, the at least one electrical load connected to the second load terminal can be characterized by a particularly low power consumption, allowing it to remain switched on for longer periods without risking deep discharge.

[0023] A state in which at least one electrical device connected to the first terminal is switched on but not actively being used can be described as a standby state. If at least one electrical device connected to the first terminal is switched off, but at least one device connected to the second terminal remains switched on, this can be described as a low standby state. Accordingly, the at least one electrical device connected to the first terminal can be described as a standby device, and the at least one electrical device connected to the second terminal can be described as a low standby device.

[0024] According to one embodiment of the method, in an additional step, a closing signal is provided to the energy storage vehicle interface by the at least one consumer connected to the second consumer terminal via the communication interface. In a further process step, the first consumer terminal is closed. In this way, a consumer connected to the second consumer terminal can control the switching state of the first consumer terminal. This is particularly advantageous if at least one consumer is connected to the first consumer terminal that can switch itself back on from a switched-off state or is automatically switched on as soon as the first consumer terminal is reconnected to the energy storage system.This implements a wake-up function for at least one consumer connected to the first consumer terminal, whereby a consumer connected to the second consumer terminal does not need to be able to communicate directly with the at least one consumer connected to the first consumer terminal.

[0025] According to one embodiment of the method, in an additional step, energy storage information is determined for the energy storage device, wherein the energy storage information preferably relates to the type of energy storage device, its capacity, and its voltage-discharge curve. In a further step, the energy storage information is stored in the data memory of the energy storage vehicle interface. These steps can take place before the energy storage device is installed in the industrial truck or when the energy storage device is replaced. They enable the industrial truck to operate in the same manner regardless of the energy storage device used.

[0026] As mentioned above, the problem is also solved by an energy storage vehicle interface according to claim 9. The energy storage vehicle interface is designed for use in a forklift truck with at least one electrical energy storage device and at least one electrical consumer. The energy storage vehicle interface comprises an energy storage terminal for connecting the energy storage device, a first consumer terminal for connecting the at least one electrical consumer, a measuring device, and a control device. The first consumer terminal can be open or closed, and when closed, it is conductively connected to the energy storage terminal. The measuring device is designed to measure an energy storage voltage applied to the energy storage terminal or an energy storage current flowing through the energy storage terminal.The control unit has a rewritable data memory in which energy storage information about the energy storage device is stored. Furthermore, the control unit is designed to calculate an energy storage state parameter from the energy storage voltage and / or the energy storage current using the energy storage information and to close or open the first load terminal depending on the energy storage state parameter.

[0027] The energy storage vehicle interface according to claim 9 is suitable for use in the method according to claim 1. The effects and advantages described above with respect to the method also apply to the energy storage vehicle interface to the extent that they pertain to it. This also applies to the specific embodiments of the energy storage vehicle interface described above with respect to the method and according to claims 2 to 8. As also described above, the use of an energy storage vehicle interface according to the invention allows, in particular, the prevention of deep discharge of the energy storage device and the combination of different types of energy storage devices with the same industrial truck system architecture.

[0028] According to one implementation of the energy storage vehicle interface, the energy storage state indicator reflects the state of charge of the energy storage system. In this implementation, the first consumer terminal is opened when the state of charge is less than a minimum standby residual charge value, and / or the first consumer terminal is closed when the state of charge is greater than a minimum standby charge value.

[0029] According to one embodiment, the energy storage state indicator reflects the time elapsed since the last use of the energy storage device. The first load terminal is opened when this time elapsed exceeds the standby time. Preferably, this time elapsed is limited by the date of the last use and a present time, whereby at the time of the last use, the measured energy storage current corresponded to at least the current consumption of the first load connected to the first load terminal in its switched-on state.

[0030] According to one embodiment, the energy storage vehicle interface has a second consumer terminal for connecting an electrical consumer of the industrial truck. The second consumer terminal can be open or closed, and when closed, it is conductively connected to the energy storage terminal. The control device is configured to open or close the second consumer terminal depending on the energy storage state parameter. An energy storage vehicle interface according to this embodiment is particularly suitable for carrying out a method according to claim 4.

[0031] The corresponding technical effects and advantages described above also apply to the energy storage vehicle interface according to this embodiment, insofar as they relate to the energy storage vehicle interface. This includes, in particular, the fact that a second consumer terminal enables the connection of at least one electrical consumer that has a lower power consumption than the at least one consumer connected to the first consumer terminal and can be configured to switch the at least one consumer connected to the first consumer terminal on or off.

[0032] According to one embodiment, the energy storage vehicle interface has a communication interface from which a communication signal can be tapped and to which at least one electrical consumer can be connected. Such an energy storage vehicle interface is particularly suitable for carrying out a method according to claim 6.

[0033] The corresponding technical effects and advantages described above also apply to the energy storage vehicle interface according to this embodiment, insofar as they relate to the energy storage vehicle interface. This includes, for example, that a connected consumer receives information about the current value of the energy storage state indicator via the communication signal and, based on this information, independently performs an action, such as switching off. For this purpose, the communication signal can preferably include the energy storage state indicator, preferably an indication that the state of charge has fallen below a residual charge warning value, and preferably an indication that the time since the last use has fallen below a standby activation duration warning value.

[0034] According to one embodiment of the energy storage interface, the communication interface is configured to receive a closing signal, and the control unit is configured to close the first consumer terminal after receiving such a signal. This allows the energy storage interface to close the first consumer terminal again if it was previously open, via a closing signal provided by one of the consumers. The corresponding consumer can thus control the energy storage interface to a certain extent. Such an energy storage interface is particularly suitable for implementing the method according to claim 7.This also offers the advantage that a consumer connected to the first consumer terminal and designed to switch itself back on when the first consumer terminal is closed after having been previously opened can be easily switched back on.

[0035] According to one embodiment, the energy storage vehicle interface comprises a housing that surrounds the measuring device and the control unit, and which has an outer surface on which the energy storage connection terminal, the first consumer terminal, and preferably the second consumer terminal and / or the communication interface are arranged. The housing holds these components together so that they form a single unit that can be installed in or removed from the industrial truck. The arrangement of the terminals and the communication interface on the outer surface allows the energy storage vehicle interface to be used as an encapsulated device in an industrial truck.

[0036] Preferably, the energy storage information is transferred to the data storage of the control unit of an energy storage vehicle interface according to the invention using a method comprising the steps of claim 8. For this purpose, information about the energy storage device, such as the type of energy storage device, its capacity and voltage-discharge curve, is determined and stored in the data storage device.

[0037] As previously mentioned, the problem is also solved by a forklift truck according to claim 14. Such a forklift truck has an electrical load and an electrical energy storage device. Furthermore, it comprises an energy storage vehicle interface according to any one of claims 9 to 13. The energy storage device is connected to the energy storage terminal, the at least one electrical load to the first load terminal, and, if the energy storage vehicle interface has a communication interface according to claim 11, to the communication interface. Such a forklift truck is particularly suitable for use in carrying out a method according to claims 1 to 8.The previously explained technical effects and advantages that result from carrying out the method and / or using the energy storage vehicle interface according to the invention also apply to the corresponding industrial trucks according to the invention, insofar as they relate to the industrial truck according to the invention and / or its operation.

[0038] According to one embodiment, the at least one electrical load connected to the first load terminal is a control unit, preferably designed to control a drive motor or a lifting device motor. It can, in particular, be a central control unit of the industrial truck. Such a control unit can be in a switched-on, standby, or switched-off state. In the switched-on state, all functions of the control unit are available, while in a standby state fewer functions are available, but power consumption is reduced.

[0039] Advantageously, the control unit automatically enters a standby state after a period of inactivity. Ideally, it also switches itself off automatically when it receives a communication signal indicating that the first load terminal is about to be opened. This staggered provision of the control unit's functions ensures that all functions relevant to the operator are available for as long as possible while minimizing energy consumption.

[0040] According to one embodiment, the industrial truck has at least one second electrical consumer and an energy storage vehicle interface according to claim 10 or 11, which is characterized by a second consumer terminal. At least one electrical consumer is connected to the second consumer terminal and preferably to the communication interface. The at least one consumer connected to the second consumer terminal can, in particular, be a consumer that has a lower power consumption than the at least one consumer connected to the first consumer terminal and that is intended to remain switched on even when the at least one consumer connected to the first consumer terminal is already switched off.The second terminal block ensures that the at least one device connected to it continues to receive power without risking deep discharge of the energy storage system due to the power consumption of the at least one device connected to the first terminal block. This is achieved by opening the first terminal block while keeping the second terminal block closed.

[0041] According to one embodiment, the at least one load connected to the second load terminal is configured to switch on the at least one load connected to the first load terminal when the latter is switched off. Preferably, this is a remote control, radio and / or telematics unit, or an operating unit with a display. Such a load connected to the second load terminal enables the at least one load connected to the first load terminal to be switched on again when the first load terminal is closed, after it had previously been opened and, consequently, the at least one load connected to the first load terminal had been switched off.A device connected to the second terminal block in this way also allows the at least one device connected to the first terminal block to be switched on without requiring direct intervention by an operator at the device connected to the first terminal block. If such a device connected to the second terminal block is a remote, radio, and / or telematics unit, switching on is achieved by sending a corresponding radio signal to this unit from an external source. In the case of an operating unit with a display, this unit can be designed in such a way that, as a result of appropriate operation of the preferably touch-sensitive display by an operator, it triggers the switching on of the at least one device connected to the first terminal block.

[0042] According to one embodiment, the at least one consumer connected to the second consumer terminal is connected to the communication interface and configured to provide a closing signal. Preferably, the at least one consumer configured to provide the closing signal is also configured to provide the closing signal as a result of operation by an operator. In this embodiment, the industrial truck has an energy storage vehicle interface with the features of claim 12, which, in particular, can receive the closing signal and, after receiving it, close the first consumer terminal. Such an industrial truck is particularly suitable for carrying out the method according to claim 7. The same technical effects and advantages apply as described above with regard to the method and the energy storage vehicle interface for the closing signal.

[0043] According to one embodiment, the at least one device connected to the second terminal has an operating device and is designed to be switched on by an operator using this device. After the second terminal is closed again, having previously been opened, the at least one device connected to the second terminal can also be switched on again. Because the electrical devices of the industrial truck are switched off in this state, there is no way to switch them on without operator interaction. The aforementioned operating device provides such a switching option, and this device can be, for example, a switch, a presence sensor such as a motion detector, or a capacitive sensor.

[0044] According to one embodiment, the at least one electrical load connected to the energy storage vehicle interface is designed to switch on when the terminal to which it is connected is closed again after having been previously open, and / or when a charging process of the energy storage system is initiated. For this purpose, it can, for example, be equipped with appropriate sensors, particularly for measuring an applied voltage supplied by an additional, battery-powered energy supply, even when the load itself is switched off. Switching on following the start of a charging process can be achieved by sending a corresponding wake-up signal to the at least one electrical load connected to the energy storage vehicle interface via the communication interface.The at least one electrical consumer connected to the energy storage vehicle interface is ready for use again after the terminal to which it is connected has been closed or a charging process has been completed, without any further action being required by an operator.

[0045] According to one embodiment, the energy storage device is a lead-acid battery, a lithium-ion battery, a fuel cell, or another high-performance battery. A high-performance battery can, in particular, be a solid-state battery or another battery with a comparably high energy density of, for example, more than 250 Wh / kg. The energy storage vehicle interface can be used with these types of energy storage devices, whereby the at least one electrical consumer is always supplied with power and information in the same way by the energy storage vehicle interface, regardless of the type of energy storage device used. In this way, the energy storage vehicle interface mediates between the energy storage device and the at least one electrical consumer, so that the latter does not need to be specifically adapted depending on the energy storage device before it can be used in the industrial truck.

[0046] The problem is also solved by a fleet of industrial trucks according to claim 21, comprising at least two industrial trucks according to claim 20, wherein at least two of the industrial trucks have different energy storage devices. Because the industrial trucks are all equipped with an energy storage vehicle interface according to one of claims 9 to 13, as described in the invention, they can be operated in the same way, even though they have at least partially different types of energy storage devices. In particular, a method according to claims 1 to 8 can be used for this purpose.

[0047] The invention is explained in more detail below with reference to the accompanying drawing. The drawing shows Fig. 1 A schematic representation of a forklift truck with an energy storage vehicle interface.

[0048] Fig.Figure 1 shows a schematic representation of the industrial truck 1. The industrial truck 1 comprises the energy storage unit 2 and the vehicle system 3.

[0049] The vehicle system 3 includes, among other things, high-current consumers 4, which include a drive motor 5 and other consumers indicated by a box with three dots. The high-current consumers 4 are connected to the switchable terminal 6, which in turn is connected to the energy storage unit 2.

[0050] The industrial truck 1 also includes low-power consumers 7, such as a foot pedal 8, and other consumers, which are also indicated by a box with three dots. The low-power consumers 7 are connected to the switchable terminal 9, which is also connected to the energy storage device 2.

[0051] In addition to the high-current consumers 4 and low-current consumers 7, the vehicle system 3 has an energy storage vehicle interface 10. It is physically and electrically separated from the energy storage device 2. In particular, it can be housed in its own enclosure.

[0052] The energy storage vehicle interface 10 has an energy storage terminal 11, a first consumer terminal 12, and a second consumer terminal 13. The first and second consumer terminals 12 and 13 are switchable and conductively connected to the energy storage terminal 11 when the terminals are closed.

[0053] Furthermore, the energy storage interface 10 comprises a control unit 14 and a measuring unit 15. The control unit 14 is configured to switch the first and second load terminals 12 and 13. The measuring unit 15, in turn, is configured to measure the energy storage voltage applied to the energy storage terminal 11 and any energy storage current flowing through the energy storage terminal 11. The measuring unit 15 is also configured to determine a time period that measures when a current last flowed through the energy storage terminal 11 corresponding to the current consumption of a load in a switched-on state, which is connected to the first or second load terminal 12 or 13.

[0054] The control unit 14 and the measuring unit 15 are connected via a data link, through which the measurement results of the measuring unit 15 can be transmitted to the control unit 14. Based on the measured energy storage voltage and current, the control unit 14 calculates an energy storage state indicator. For this purpose, the control unit accesses energy storage information stored in its data memory. The energy storage state indicator can, in particular, reflect the state of charge of the energy storage device. Depending on the energy storage state indicator, the control unit 14 switches the first and second load terminals 12 and 13. Furthermore, the energy storage state indicator can be accessed by other loads via the data interface 16.

[0055] Consumers 17 of a first group are connected to the first consumer terminal 12. This group includes, among other things, a control unit 18 and others indicated by a box with three dots. For example, this could be an air conditioning system. In the present embodiment, the control unit 18 is configured to control the drive motor 5, for which it receives data from the accelerator pedal 8.

[0056] The loads 17 connected to the first load terminal 12 can be in a switched-on state, a standby state, or a switched-off state. In a standby state, a load 17 can provide limited functions and therefore has lower power consumption.

[0057] The first load terminal 12 can be opened, thus preventing the loads 17 connected to the first load terminal 12 from consuming any further current. This prevents deep discharge of the energy storage device 2. The first load terminal 12 is opened by the control unit 14 as soon as the state of charge falls below a minimum standby residual charge value. Once the minimum standby residual charge value has been undershot, the energy storage device 2 should be recharged. When it is sufficiently charged again after a corresponding charge and a minimum standby charge value is exceeded, the first load terminal 12 is closed again.

[0058] Consumers 19 from a second group are connected to the second consumer terminal 13. These include, among other things, a control unit with display 20 and further consumers indicated by the box with the three dots. These could be, for example, a radio, remote, or telematics unit.

[0059] The control unit with display 20 is designed to switch the control unit 18 back on when it is switched off. An operator can use the display for this purpose. Switching the control unit 18 back on via the control unit with display 20 may be necessary, in particular, if the first consumer terminal 12 was previously opened, causing the control unit 18 to be switched off.

[0060] To prevent the loads 19 connected to the second load terminal 13 from causing deep discharge of the energy storage device, the control unit 14 can open the second load terminal 13. It opens the second load terminal 13 specifically as soon as the state of charge falls below a minimum low-standby residual charge value. Once the energy storage device has been recharged to a state of charge greater than a minimum low-standby charge value, the control unit 14 closes the second load terminal 13 again. A load 19 connected to the second load terminal 13 can then be switched on again by operating a corresponding control unit.

[0061] In a state where the charge value is greater than the low-standby minimum residual charge value but less than the standby minimum residual charge value, the first load terminal 12 is open, while the second load terminal 13 is closed. Consequently, only the loads 19 connected to the second load terminal 13 can be switched on. This state is referred to as low-standby.

[0062] If, following a low-standby state, the first load terminal 12 is subsequently closed, at least some of the loads 17 connected to the first load terminal 12 may remain switched off. However, they can be switched on again at any time. For example, an operator can operate a suitably trained load 19 connected to the second load terminal 13, such as the control unit with display 20. Alternatively, there may be loads 17 connected to the first load terminal 12 that are switched on directly after the load terminal 12 is closed, or that switch themselves back on reliably without requiring any further interaction with other loads or an operator.

[0063] A state in which both the first and second consumer terminals 12, 13 are closed, the consumers 17 connected to the first consumer terminal 12 are in a standby state and the consumers 18 connected to the second consumer terminal 13 are switched on, can be called standby.

[0064] Furthermore, a load 17 connected to the first load terminal 12 can be connected to the communication interface 16. The control unit 14 can, for example, inform the loads 17 connected to the first load terminal 12 whether the charge level is approaching the minimum standby residual charge value. Using such information, one of the loads 17 connected to the first load terminal 12 can switch itself off before the first load terminal 12 is opened.

[0065] In principle, one of the consumers 19 connected to the second consumer terminal 13 can also be connected to the communication interface 16. This is particularly useful if one of the consumers 19 can provide a closing signal and the control unit 14 is configured to close the first consumer terminal 12 upon receiving the closing signal. If there is also a consumer 17 connected to the first consumer terminal 12 that can switch itself back on after being switched off, the corresponding consumer 17 can simply be switched on by sending a closing signal, without requiring a communication link between a consumer 19 connected to the second consumer terminal 13 and a consumer 17 connected to the first consumer terminal 12.

[0066] In the embodiment shown here, a different setup is demonstrated. There is a direct connection between the loads 19 connected to the second load terminal 13 and the loads 17 connected to the first load terminal 12, via which the loads 17 connected to the first load terminal 12 can be switched on.

[0067] The energy storage device 2 can have different characteristics. For example, it could be a lead-acid battery or a lithium-ion battery. The loads 17 and 19 connected to the first or second load terminal are not directly connected to the energy storage device 2. Rather, they are connected to it via the energy storage vehicle interface 10, from which they also receive an energy storage status parameter such as the state of charge. Such information is typically only provided by a modern battery with a battery management system, such as a lithium-ion battery. However, due to the indirect connection of the loads 17 and 19 connected to the first or second load terminal, it is irrelevant whether it is actually such an energy storage device.They can always be operated in the same way regardless of the type of energy storage, because the energy storage vehicle interface 10 provides the relevant information by means of the energy storage state parameter and switches off terminals 12, 13, as a modern energy storage device would do.

[0068] It is also conceivable that the energy storage device 2 is indeed a lithium-ion battery, but that it originates from a different manufacturer than the industrial truck 3. Since the battery management systems that typically provide battery status information do not have a standardized bus communication system that allows cross-manufacturer communication between the energy storage device and the vehicle, the use of an energy storage interface 10 according to the invention can also be advantageous in this case, i.e., for operating energy storage devices 2 from a first manufacturer with industrial trucks 3 from a second manufacturer. Reference symbol: 1 forklift truck 2 Energy storage 3 Vehicle system 4 high-voltage consumers 5 Drive motor 6 terminals 7 Low-energy consumers 8 Accelerator pedal 9 terminal 10 Energy storage vehicle interface 11 Energy storage terminal 12 First consumer terminal 13 Second consumer terminal 14 Control unit 15 Measuring device 16 Communication interface 17 Consumers connected to the first consumer terminal 18 Control unit 19 Consumers connected to the second consumer terminal 20 Display

Claims

[1] Method for operating a forklift truck (1) with • at least one electrical energy storage device (2), • at least one electrical appliance (17, 18, 19, 20) and • an energy storage vehicle interface (10) comprising an energy storage terminal (11), a first consumer terminal (12) and a preferably rewritable data storage on which energy storage information about the energy storage device (2) is stored, • wherein the energy storage device (2) is connected to the energy storage terminal (11), at least one consumer (17, 18) is connected to the first consumer terminal (12), the first consumer terminal (12) may be open or closed, and the energy storage terminal (11) is electrically connected to the first consumer terminal (12) when the first consumer terminal (12) is closed, comprising the steps: • Measuring an energy storage voltage applied to the energy storage terminal (11) and preferably an energy storage current flowing through the energy storage terminal (11), • Determining an energy storage state parameter using the energy storage information and the energy storage voltage, and preferably the energy storage current, • Opening of the first consumer terminal (12) depending on the energy storage state parameter, • preferably charging the energy storage device and • Re-closing of the first consumer terminal (12) depending on the energy storage state parameter. [2] Method according to claim 1, characterized by , that • the energy storage state indicator reflects a state of charge of the energy storage (2) and • the first consumer terminal (12) is opened when the state of charge is less than a minimum standby residual charge value, and / or • the first consumer terminal is closed when the state of charge is greater than a minimum standby charge value. [3] Method according to claim 1 or 2, characterized by , that • the energy storage state indicator reflects a time period since the last use of the energy storage (2), • the first consumer terminal (12) is opened when the time duration is greater than a standby duration. [4] Method according to any one of claims 1 to 3, characterized by , that • the industrial truck (1) has at least two electrical consumers (17, 18, 19, 20), • the energy storage vehicle interface (10) has a second consumer terminal (13) which can be open or closed, • the energy storage terminal (11) is electrically connected to the second consumer terminal (13) when the second consumer terminal (13) is closed, • at least one consumer (19, 20) is connected to the second consumer terminal (13) and • the following additional steps take place: ◯ Opening of the second consumer terminal (13) depending on the energy storage state parameter, ◯ Re-closing of the second consumer terminal (13) depending on the energy storage state parameter. [5] Method according to claim 4, characterized by , that • the second consumer terminal (13) is opened when the state of charge is less than a low-standby minimum residual charge value, and / or • the second consumer terminal (13) is closed when the state of charge is greater than a low standby minimum charge value. [6] Method according to any one of claims 1 to 5, characterized by , that • the energy storage vehicle interface (10) has a communication interface (16), • and an additional step takes place: providing a communication signal that includes the energy storage state indicator, preferably an indication that the state of charge has fallen below a residual charge warning value, and preferably an indication that the time since last use has exceeded a standby activation time warning value. [7] Method according to claim 6, characterized by the additional steps: • Providing a closing signal to the energy storage vehicle interface (10) by the at least one consumer (19, 20) connected to the second consumer terminal (13) via the communication interface, • Closing the first consumer terminal (12). [8] Method according to any one of claims 1 to 7, characterized by the additional steps: • Determining energy storage information for the energy storage device (2), wherein the information preferably relates to a type of energy storage device (2), its capacity and voltage-discharge curve, and • Storing the energy storage information in the data storage of the energy storage vehicle interface (10). [9] Energy storage vehicle interface (10) for a forklift truck (1) comprising at least one electrical energy storage device (2) and at least one electrical consumer (17, 18, 19, 20) • an energy storage terminal (11) for connecting the energy storage device (2), • a first consumer terminal (12) for connecting the at least one electrical consumer (17, 18, 19, 20), which can be open or closed, being conductively connected to the energy storage terminal (11) when it is closed, • a measuring device (15) designed to measure an energy storage voltage applied to the energy storage terminal (11) or an energy storage current flowing through the energy storage terminal, • a control device (14) which has a preferably rewritable data storage in which energy storage information for the energy storage device (2) is stored, and which is configured to calculate an energy storage state characteristic value from the energy storage voltage and / or the energy storage current using the energy storage information and to close or open the first consumer terminal (12) depending on the energy storage state characteristic value. [10] Energy storage vehicle interface (10) according to claim 9, characterized bya second consumer terminal (13) for connecting an electrical consumer (19, 20) of the industrial truck (1), which can be open or closed, being conductively connected to the energy storage terminal (11) when it is closed, and the control device (14) is configured to close or open the second consumer terminal (13) depending on the energy storage state parameter. [11] Energy storage vehicle interface (10) according to one of claims 9 to 10, characterized by a communication interface (16) from which a communication signal can be tapped and to which at least one electrical consumer (17, 18, 19, 20) can be connected. [12] Energy storage vehicle interface (10) according to one of claims 9 to 11, characterized by, that the communication interface (16) is configured to receive a closing signal, and the control device (14) is configured to close the first consumer terminal (12) after receiving a closing signal. [13] Energy storage vehicle interface (10) according to any one of claims 9 to 12, characterized by a housing that surrounds the measuring device (15) and the control device (14) and that has an outer surface on which the energy storage terminal (11), the first consumer terminal (12) and preferably the second consumer terminal (13) and / or the communication interface (16) are arranged. [14] Industrial truck (10) comprising an electrical energy storage device (2), at least one electrical consumer (17, 18, 19, 20) and an energy storage vehicle interface (10) according to one of claims 9 to 13, wherein the energy storage device (2) is connected to the energy storage terminal (11), the at least one electrical consumer (17, 18) is connected to the first consumer terminal (12) and preferably to the communication interface (16). [15] Industrial truck (1) according to claim 14, characterized by , that the at least one electrical consumer (17, 19) connected to the first consumer terminal (12) is a control unit (18) which is preferably designed to control a drive motor (5) or a lifting device motor. [16] Industrial truck (1) according to claim 14 or 15, characterized byat least one second electrical consumer (19, 20) and an energy storage vehicle interface (10) according to one of claims 10 or 11, wherein at least one electrical consumer (19, 20) is connected to the second consumer terminal (13). [17] Industrial truck (1) according to claim 16, characterized by , that the at least one consumer (19, 20) connected to the second consumer terminal (13) is designed to switch on the at least one consumer (17, 18) connected to the first consumer terminal (12) and is preferably a remote, radio and / or telematics unit or an operating unit with display (20). [18] Industrial truck (1) according to one of claims 16 or 17 and an energy storage vehicle interface (12) according to one of claims 12 to 14, characterized by, that the at least one consumer (19, 20) connected to the second consumer terminal (13) is connected to the communication interface (16) and is designed to provide a closing signal. [19] Industrial truck (1) according to any one of claims 16 to 18, characterized by , that the at least one consumer (19, 20) connected to the second consumer terminal (13) has an operating device and is designed to be switched on by an operator using the operating device. [20] Industrial truck (1) according to any one of claims 14 to 19, characterized by , that the energy storage device (2) is a lead-acid battery, a fuel cell, a lithium-ion battery or another high-performance battery. [21] Fleet of industrial trucks comprising at least two industrial trucks (1) according to claim 20, wherein at least two industrial trucks (1) have energy storage devices (2) of different types.

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