Battery charger

Abstract

A charger for a battery, in particular of a forklift truck, comprising a device body (18), a charging cable (22) of which one end is connected to the device body (18) and of which the other end has a charging plug (24), and a control unit designed for processing signals, wherein a holding device (26) with a charging plug detection is provided for the charging plug (24), which detects the charging plug in the holding device and reports it to the control unit, which generates a charging plug control signal, characterized in that the charger is designed as a charger (30) carried on the forklift truck and the charging plug (24) is provided for connection to an external voltage source and the charger, upon detection of the charging plug (24), releases an immobilizer provided for the forklift truck.

Description

[0001] The present invention relates to a charger for a battery, in particular for a battery of a forklift truck.

[0002] Electrically powered industrial trucks have one or more batteries carried on the vehicle. These batteries can remain in the operator's compartment for recharging. During the recharging process, the battery is connected to an external power source via an electrical connector. A charger is connected between the external power source and the battery, converting the voltage from the external power source into a charging voltage. A fundamental distinction is made between industrial trucks with an internal and those with an external charger. The internal charger is connected to an external power source for charging. The connection between the charger and the battery is located within the vehicle. With an external charger, the charger is also connected to the power source, but via a charging cable and plug, it is connected to a charging socket provided on the industrial truck.

[0003] From DE 10 2014 113 461 A1, a system for connecting a battery located in a vehicle to a preferably stationary charger is known. This system includes a contact unit attached to the battery with a charging connector that is electrically connected to the battery. A switching device can connect the battery to an electrical system in the industrial truck. An actuating mechanism is provided in the contact unit, which can be actuated by a section of the charging connector when a charging plug is inserted into the charging connector and the switching device is moved to the open position.

[0004] From DE 2015 109 081 A1, a forklift truck with a charging plug connection is known. The connection includes a plug element arranged behind at least one cover flap, which is accessible to a mating plug element of a charging cable when the cover flap is open. The cover flap is pre-tensioned into its closed position by a tensioning element and opens inwards towards the plug element with a rotational movement of the flaps when the mating plug element comes into contact with the cover flap.

[0005] A charging device with a lamellar closure for an electric vehicle is known from DE 10 2011 006 473 A1. In one embodiment, the charging device is closed by a pair of flaps which, during the charging process, rest against a charging plug or its cable to secure it.

[0006] US 2013 / 0300429 A1 discloses a charger with a charging plug for establishing a charging connection with electric vehicles. When not in use, the charging plug can be inserted into a holding device on the charger. An electrical test of the charging plug can be performed using a diagnostic unit.

[0007] DE 10 2011 010 774 A1 discloses a charging station and a charging plug arranged in a charging cable, which, when not in use, is inserted into a recess of a charger housing. A detector unit recognizes whether the charging plug has been moved into this resting position and reports this to a control unit. Depending on the detection of the charging plug, a protective switching element is activated by the control unit.

[0008] CN 106 097 890 A discloses a charger with a charging plug, wherein a holding device for the charging plug has a sensor for detecting the charging plug 3. When a plug is inserted into the holding device, information about a charging process is displayed on a screen.

[0009] DE 10 2009 017 089 A1 discloses a charging device with a plug wake-up signal which wakes the charging device from sleep mode when the charging plug is inserted into a vehicle to be charged.

[0010] JP 2013 046 477 A shows a charger and a charging plug, which can be inserted into a holding device of the charger.

[0011] DE 20 2018 000 487 U1 relates to a forklift truck with an interchangeable battery unit that also includes a charger. The unit can be connected to an external power source via a charging cable.

[0012] The invention is based on the objective of providing a battery charger that can be used particularly economically for industrial trucks.

[0013] According to the invention, the problem is solved by a charger for a battery having the features of claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0014] The charger according to the invention is designed or intended for use with a battery, in particular a battery in a forklift truck, for example a traction battery. The charger can also be designed for several batteries arranged in the forklift truck. The charger has a device body and a charging cable, one end of which is connected to the device body and the other end of which has a charging plug. The device body here refers to all components of the charger that are necessary for converting an external voltage for the charging process.

[0015] The device body does not necessarily need to be enclosed in a housing. The charging cable connects to the forklift truck, or, in the case of an external charger, from the forklift truck to an external power source. A control unit is provided to process received and transmitted signals, thereby controlling the operation of the charger and exchanging data and signals with external devices, such as a forklift truck, via the communication interface. According to the invention, a holding device with plug detection is provided for the charging plug. When a charging plug is detected in the charging plug detection device or the holding device, the charger's control unit generates a charging plug control signal.The charging plug control signal can subsequently be evaluated in various ways. For example, the charger can be switched to an energy-saving mode, or a measurement of the electrical properties of the charging plug and / or the cable can be triggered. The charger according to the invention thus provides a configuration in which the charging plug can be stored in the holding device when not in use. This alone results in better utilization of the charger, as a defined storage space is provided for the charging plug. Furthermore, advantageous functionalities on the vehicle can be triggered in response to the charging plug control signal, such as an energy-saving mode and / or an electrical check.

[0016] In a preferred embodiment, the charger switches to energy-saving mode when the charging plug is inserted into the holding device. In this energy-saving mode, all or almost all of the charger's electrical components can be switched off or reduced, thus preventing unnecessary energy consumption. In particular, energy consumption during the charger's standby operation and its control unit can also be avoided. The particular advantage of the charger according to the invention is that the holding device fulfills a dual function. On the one hand, it serves as a defined storage position for the charging plug; on the other hand, it serves to switch the charger into energy-saving mode.

[0017] In a particularly preferred embodiment, the holding device with charging plug detection is provided on the device body. The spatial proximity between the holding device and the device body makes the assignment of the holding device to the charger unambiguous.

[0018] In a preferred further development of the inventive method, the charging plug detection system includes a switch for detecting the charging plug. Switches for detecting a charging plug are already known in the area of ​​charging sockets. In the embodiment according to the invention, however, the switch is arranged on the charger and is configured to generate a charging plug control signal via the control unit for the functionality of the charger and / or the industrial truck. This distinguishes the intended switch from other known switches that, for example, switch upon electrical connection or trigger a locking mechanism for the charging plug in its inserted position. The switch can, for example, be designed mechanically, inductively, capacitively, magnetically, optically, or as a reed switch.

[0019] Another significant advantage of the plugged-in charging connector is that the connector detection system can perform an electrical test of both the connector and the charging cable. When plugged in, both the charging cable and the connector are connected to the charger. This creates a closed connection, allowing for an electrical test of the connector and cable. This electrical test is preferably performed before the charger switches to its energy-saving mode. The electrical test of the charging connector preferably involves measuring its contact resistance. The contact resistance of the charging connector provides information about any contamination or mechanical and / or chemical damage to the connector. Damage to the charging cable can also be detected and recorded in this way.Such self-testing of the mechanically stressed parts of the charger offers a particular advantage, especially during extended use, where, for example, arcing occurring at the charging contacts during the charging process can lead to material abrasion and / or oxidation of the plug contacts, thus negatively impacting the contact resistance. This eliminates the need for additional testing steps of the charging plug and cable. The control unit also serves to process signals, preferably internal ones. The generated charging plug control signal can be exchanged with a resistance measurement of the charging plug, power electronics, a communication module, and a human-machine interface (HMI). This signal exchange preferably takes place via a communication interface.

[0020] According to the invention, the charger is designed as a charger carried on the vehicle. In this case, the charging plug is provided for connection to an external voltage source. The external voltage source can supply two-phase alternating current or three-phase alternating current, with the charging plug being designed accordingly. When using a vehicle-mounted charger, power is drawn from the external voltage source, converted into power for charging the battery, and thus supplies the industrial truck and its battery accordingly.

[0021] The charger can be designed to automatically retract the charging cable, so that when the charging plug is in its holder, no cable is left loose on the forklift. When using an internal charger, it is advantageous and in accordance with the invention if, upon detection of the charging plug, the immobilizer on the forklift is deactivated. It is generally known that a forklift's control system activates an immobilizer precisely when charging is in progress. This ensures that the vehicle is not moved during charging. By reinserting the charging plug into its holder on the charger, the vehicle is signaled that the charging process is complete and that the charging plug and cable are stowed away.This is particularly advantageous with internal chargers, as simply completing the charging process does not reliably indicate that the forklift can safely continue driving. However, even with external chargers, such a deactivation of the immobilizer helps to prevent premature starting.

[0022] In an alternative configuration, the charger is designed as an external charger with a connection to an external power source. The charging plug connects the charger to a charging socket located on the vehicle side, through which the batteries are then charged. The process of placing the charging plug in a holder and simultaneously switching the charger into an energy-saving mode is particularly important for the external charger. The designated storage location for the charging plug prevents it from being stored incorrectly or left lying around near the charger. The latter poses a particular danger when handling forklifts or other industrial trucks, should they run over and damage the charging plug.

[0023] It is also preferable to record the time period during which the charging plug is not inserted into the holding device. This allows, for example, an analysis of how the charger and / or the connected industrial truck is used. In particular, this also allows conclusions to be drawn about the time period during which the industrial truck was not charged, which, together with the data from the operation of the industrial truck, allows conclusions to be drawn about the time period during which the vehicle was neither moved nor charged.

[0024] Two preferred embodiments are explained in more detail below. It shows: Fig. 1. A forklift truck with a non-inventive external charger in a schematic side view, Fig. 2 the forklift truck Fig. 1, with an internal charger in a schematic side view and Fig. 3 A schematic view of the charger with its components.

[0025] Fig. Figure 1 schematically shows an electrically powered industrial truck in the form of a counterbalance forklift, equipped with a charging socket 10 on a battery compartment 12. In the example shown, the battery compartment 12 is located below an operator station 8. Other positions for the battery compartment 12 and the charging socket 10 are also possible. The vehicle shown in the side view has a base body 2 with a front and rear axle. A lifting mast 3 with a height-adjustable load carriage 4 is provided on the base body 2. The load carriage 4 moves a load fork 14. The base body 2 of the industrial truck shown has a driver's cab 1, which is equipped with a protective roof 5. An operator station 8 is provided above the battery compartment 12. A non-inventive, external charger 16 is schematically shown in close proximity to the industrial truck.The charger 16 has a device body 18, which is exemplified in . Fig. Figure 1 shows the external charger 16. This external charger does not necessarily require a housing with a defined shape, but can also be, for example, built into a wall. Nevertheless, the electrical components of the charger, which convert an external supply voltage into a charging voltage, are collectively referred to as the device body. The charger 16 shown also has a display 20, which can show information about the status of the charger, the battery, and other information relating to the charging process. The device body 18 also has a charging cable 22, one end of which is connected to the charger 16 and its device body 18, and the other end of which terminates in a charging plug 24. Fig. 1 The charging plug 24 is arranged in a schematically depicted holding device 26. In this arrangement, there is an electrically closed connection via the charging cable 22 and the charging plug 24 from the charger 16 and back to this charger.

[0026] For charging, the charging plug 24 is pulled out of the holding device 26 and connected to the charging socket 10. In this connected state, the forklift's battery is charged, and the charging process is monitored by the charger. The charger's power supply from an external voltage source is not shown in the schematic diagram. When the charging process is complete or has not yet started, the charging plug 24 is in the holding device 26. In this state, the charger 16 is in an energy-saving mode in which most of its components are switched off. Furthermore, the charging plug 24 in the holding device 26 allows for electrical testing of the charging plug 24 and charging cable 22. This allows, for example, the contact resistance of the charging plug to be measured in order to detect mechanical damage or contamination.Mechanical damage to the charging cable can also be detected by checking the total resistance.

[0027] Fig. Figure 2 also shows a counterbalance forklift in a schematic side view. The same reference symbols denote the same parts, as with the counterbalance forklift from [reference missing]. Fig. 1. The counterbalance forklift made of Fig. 2 is equipped with an internal charger 30 according to the invention. The internal charger 30 is located in a compartment 28 below the operator station 8. The compartment 28, which can also accommodate, for example, the battery, has a cover 31, which is shown in a broken view to allow a view into the compartment 28. The charger 30 has a display 32, which, for example, displays status messages about the charger. Furthermore, the charger has a charging cable 24 and a charging plug 36, which is attached to the charger 30 in a holding device. For the charging process, the charging plug 36 is removed from the holding device and connected to a voltage source. This voltage source can be a conventional AC voltage or a three-phase voltage; the charging plug is designed accordingly. The charger 30, thus supplied with voltage, initiates the charging process, taking into account battery-specific parameters.

[0028] Disconnecting the charging plug 36 and placing it in the holding device on the internal charger switches the charger 30 into an energy-saving mode. This is particularly advantageous with an internal charger, as the charger's components must be powered by the onboard battery. Therefore, the energy-saving mode on the charger also increases the operating range of the electric battery. Furthermore, placing the charging plug 36 in the holding device ensures that the charging cable 24 is stowed back on board the forklift and thus does not pose a hazard or obstruction to its operation. Another significant advantage of placing the charging plug 36 in the holding device is that it allows the forklift to be deactivated if an immobilizer is normally in place during the charging process.

[0029] Fig.Figure 3 shows a schematic view of a charger 38. The charger 38 is designed as an external charger that is connected to a voltage source via the terminal 40. The charger 38 has a charging cable 42 with a charging plug 44, which is held in a retaining device 46. The retaining device 46 holds the charging plug when it is not connected to the vehicle for charging. A plug detection device 48 is provided via the retaining device 46, which detects whether the charging plug 44 is positioned in the retaining device 46. A resistance sensor 50 also interacts with the retaining device 46 and serves to detect electrical resistance in the charging cable and / or the charging plug.

[0030] A control unit 52 is also centrally located in the charger 38. The control unit 52 plays a key role in the charging process, as it establishes the electrical connection between the mains connection 40 and the charging plug 44 via the power electronics 54. During the charging process, the control unit 52 controls the power electronics to carry out the charging process according to the battery and its requirements. The control unit 52 also has a communication interface 56, which can be configured, for example, as a CAN bus. The control unit 52 receives signals via the communication interface 56, such as those indicating to the battery that it is ready for charging. The charger 38 is also equipped with an operating and / or display unit 58, which allows settings for the charger 38 to be configured.

[0031] For charging, the charging plug 44 is inserted into a corresponding socket on the industrial truck. The charging process is initiated. Additional information, such as details about the battery being charged, can be provided at the communication interface 56 during the charging process. For this purpose, the communication interface 56 can be connected, for example, to signal lines in the charging cable 42. Once the charging process is complete, when the charging plug 44 is placed back in the holding device 46, the control unit 52 triggers a charging cable control signal. This signal can, for example, trigger the charger 38 to switch to an energy-saving mode. Alternatively or additionally, it can also be provided that a test of the charging cable 42 and the charging plug 44 is performed. Reference symbol list 1 driver's cab 2 basic shapes 3 Lifting frame 4 load sleds 5 Driver protection roof 8 operator stations 10 charging socket 12 Battery compartment 14 load fork 16 external charger 18 device bodies 20 ads 22 charging cables 24 charging plugs 26 Holding device 28-fold 30 internal charger 31 Cover 32 Display for status messages 34 charging cables 36 charging plugs 38 charger 40 network connection 42 charging cables 44 charging plugs 46 Holding device 48 Plug identification 50 resistance sensor 52 Control unit 54 Power Electronics 56 Communication interface 58 Control or display unit

Claims

A charger for a battery, in particular of a forklift truck, comprising a device body (18), a charging cable (22) of which one end is connected to the device body (18) and of which the other end has a charging plug (24), and a control unit designed for processing signals, wherein a holding device (26) with a charging plug detection is provided for the charging plug (24), which detects the charging plug in the holding device and reports it to the control unit, which generates a charging plug control signal, characterized in that the charger is designed as a charger (30) carried on the forklift truck and the charging plug (24) is provided for connection to an external voltage source and the charger, when the charging plug (24) is detected, releases an immobilizer provided for the forklift truck. Charger according to claim 1, characterized in that, in response to the charging plug control signal, the charger switches to an energy saving mode. Charger according to claim 1 or 2, characterized in that the holding device (26) with the charging plug detection is provided on the device body (18). Charger according to claim 1 or 2, characterized in that the charging plug detection has a switch for detecting the charging plug (24). Charger according to one of claims 1 to 4, characterized in that the charging plug detection performs an electrical test of the charging plug (24) and / or the charging cable (22). Charger according to one of claims 1 to 5, characterized in that the charging plug detection measures the electrical contact resistance of the charging plug (24). Charger according to claim 5 or 6, characterized in that the control unit sends a signal about values ​​of the electrical test of the charging plug to a communication interface. Charger according to one of claims 1 to 7, characterized in that the charger is designed as an external charger (16) with a connection for an external voltage source and the charging plug (24) for connection to a charging socket (10) on the industrial truck. Charger according to one of claims 1 to 8, characterized in that the control unit is designed to detect a period of time during which the charging plug is not inserted into the holding device.

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