Battery powered industrial truck

Abstract

The invention relates to a battery powered industrial truck. Comprising at least one battery-powered drive, having a main battery carried for power supply and a battery charger via which the main battery can be charged and discharged, providing one or more plug-in batteries with at least one plug-in position having electrical contacts for connection to a control module for each plug-in battery, the control module is configured to control at least two of the following operations and / or charging modes on the industrial truck: a reduced power operation mode in which the control module is operated to extract power at a rate at which power extracted from the main battery is less than a maximum output power of the main battery, a power optimization operation mode in which the control module is operated to provide an amount of power such that the plug-in battery is additionally connected and supplied with energy, a plug-in battery charging mode in which the control module is operated to extract charging power from the plug-in battery to the main battery; and a charger charging mode of charging the plug-in battery from the battery charger.

Description

Technical Field

[0001] The invention relates to an industrial truck comprising at least one battery-powered drive, wherein the industrial truck is powered by a main battery carried with the truck. Background Art

[0002] DE 10 20 20 13 2 3 9 8 A1 discloses a forklift truck with an electric drive motor and a rechargeable lead-acid battery, by means of which the electric drive motor can be supplied with electrical energy via an electronic control device. The truck is provided with a covering device having first and second on-board connection contacts, which are connected to the electrodes of the rechargeable lead-acid battery. In addition, at the forklift truck, an auxiliary battery can be inserted into the holding device. The forklift truck uses a low-voltage switching circuit, which cuts off the circuit if the voltage of the auxiliary battery drops below the rated voltage of the lead-acid battery.

[0003] In the current situation, lead-acid batteries or lithium-ion batteries are applied to forklift trucks. The batteries can only be recharged inside or outside the vehicle using an external power source. The recharging process takes place when the truck is parked at an external charging device. Dynamic recharging during operation is possible by using the truck's inductive power supply. However, this technology is rather expensive, as the warehouse floor must be equipped with charging coils, which are usually sunken into the concrete to facilitate charging during operation. Summary of the invention

[0004] The technical problem of the present invention is to provide an industrial truck with a more flexible charging concept.

[0005] The invention solves this technical problem with an industrial truck comprising the features of claim 1. Further embodiments are subject matter of the independent claims.

[0006] The industrial truck according to the present invention comprises at least one battery-powered drive, the main battery being carried on the vehicle for power supply. In addition, the industrial truck comprises a battery charger, by which the main battery can be charged and discharged. At least one insertion position is provided on the industrial truck for one or more plug-in batteries on the truck. The insertion position has electrical contacts for connecting each of the at least one plug-in battery to a control module. The control module is adapted to control at least two of the following operating modes and charging modes of the industrial truck. The first operating mode refers to a reduced power operation, in which the control module is controlled so as to provide a power rate value at which the power extracted from the main battery is less than the maximum output power of the main battery. In this reduced power operating mode, the power extracted from the main battery is limited and is lower than the maximum output power value that can be extracted from the main battery. In addition, there is a power optimization operating mode, in which the control module is operated to provide an amount of power so that at least one plug-in battery additionally contributes to the power supply of the truck. In the power optimization operating mode, the plug-in battery supplies additional power to the industrial truck. In addition to these two operating modes, several charging modes involving plug-in batteries can be used for industrial trucks. In the plug-in battery charging mode, the control module is configured to extract charging power from the at least one plug-in battery to recharge the main battery. In other words, the plug-in battery at least partially charges the main battery in the plug-in battery charging mode. In addition, there is a charging mode in which the at least one plug-in battery is recharged from the battery charger. In particular, the plug-in battery is recharged when it is plugged in at the vehicle. According to the invention, at least two of the above four modes are provided on the truck according to the invention.

[0007] In a preferred embodiment, the control module switches to the plug-in battery charging mode when the industrial truck is stationary or traveling at a constant speed. In this plug-in battery charging mode, if the industrial truck is stationary or traveling at a constant speed, the plug-in battery contributes to charging the main battery. The constant speed results in a constant rate of power being drawn from the plug-in battery, so that the plug-in battery can also preferably recharge the main battery at a constant rate.

[0008] In another preferred embodiment, the control module is activated during regenerative braking of the industrial truck so as to apply at least a portion of the generated electricity as charging power to at least one plug-in battery. Thus, such regenerative braking is used not only to recharge the main battery but also to recharge the plug-in battery, which increases the flexibility of the plug-in battery in use. Thus, the advantages of regenerative braking also work for the plug-in battery, not just for the main battery.

[0009] In a preferred embodiment, the control module also has an operating mode optimized for a predetermined operating period (e.g., for an operating period corresponding to an operating shift of the industrial truck), wherein power is drawn from the at least one plug-in battery according to the state of charge (SOC) of the main battery. The at least one plug-in battery and the main battery cooperate to enable the industrial truck to be operated throughout the shift.

[0010] In another preferred embodiment, the control module includes a DC / DC converter via which at least one plug-in battery is connected to an electrical grid or electrical bus connected to the electrical system of the vehicle. The electrical grid or system of the vehicle includes at least one battery-powered drive and other electrical loads, such as motors and devices. If necessary, the DC / DC converter adjusts the voltage of the plug-in battery to the rated voltage of the electrical grid of the vehicle.

[0011] In a preferred embodiment, the value of the power extracted from the main battery in the power reduction operating mode is less than a limit value. The limit value is selected so that in the event of an additional power demand of the further loads, the maximum power demanded together with the power already extracted from the main battery remains less than the maximum possible output power of the main battery. In this power reduction operating mode, the main battery always has sufficient capacity to meet the additional power demand of the further loads, at least for a short period of time.

[0012] In a preferred embodiment, the traction drive is fed by the main battery if the industrial truck is operated in the no-plug-in battery mode. In the no-plug-in battery mode, the main battery is used to power the traction drive of the industrial truck. Preferably, in the no-plug-in battery mode, the power load is reduced, for example in the case where the forklift is driven at a constant speed (without acceleration) and in the case where there is no additional power consumed by, for example, lifting operations.

[0013] In a preferred embodiment, the control module is configured to extract maximum power from the plug-in battery and the control module operates in a power optimization mode of operation. If the power demand exceeds the maximum power of the main battery, the additional power extracted from the plug-in battery is used. In this embodiment of the power optimization mode of operation, if the power supply of the main battery is insufficient, the plug-in battery is used as an additional power source.

[0014] In a preferred embodiment, an auxiliary operating mode is provided in which the control module is controlled to draw power only from the plug-in battery. This may occur when the main battery is not usable, for example, when the main battery overheats. In this case, the plug-in battery can fully power the industrial truck while the main battery is cooling down. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The specific embodiments of the present invention are described with reference to the following drawings:

[0016] Figure 1 A schematic diagram showing a modularly designed energy system for an industrial truck, and

[0017] Figure 2 A modularly designed lithium-ion battery system implemented in an industrial truck is shown. DETAILED DESCRIPTION

[0018] Figure 1 An energy management system 10 connected to a plug-in battery 12 and a rechargeable main battery 14 is shown. The energy management system 10 includes a control module that controls the batteries 12, 14 via lines 16 and 18. In addition, the control module receives the SOC value of the main battery 14 and other values ​​such as battery temperature via line 18. For the plug-in battery 12, line 16 provides the control module with information about the number of plug-in batteries and the corresponding SOC value. The main battery 14 is connected to a motor controller 20 to directly provide energy to a forklift motor 22. The forklift motor 22 can be a traction drive for an industrial truck (particularly, a steering traction wheel). In addition to the forklift motor 22, there are also on-board auxiliary loads 24 of the industrial truck. Energy for auxiliary loads (such as lights, refrigerated trucks, displays, etc.) is also provided by the main battery 14. A DC / DC converter 26 is required for appropriate voltage conversion. The motor controller 20 additionally includes a DC / AC converter that allows the motor controller 20 to convert the output voltage and current from the main battery 14 as DC into AC to meet the request current of the forklift motor 22.

[0019] The plug-in battery 12 is connected to a bidirectional DC / DC converter 28. The bidirectional DC / DC converter 28 allows charging and discharging of the plug-in battery 12 depending on the operating mode. Figure 1 As can be seen, energy from the plug-in battery may be directed to the motor controller 20 and converter 26 for the auxiliary load 24 , or to the rechargeable main battery 14 .

[0020] Figure 2 An industrial truck is shown, which includes a plug-in battery module 12, a bidirectional DC / DC converter 28, a main battery 14 and a motor controller 20 including a DC / AC converter and a forklift motor 22. In addition, for the above-mentioned energy management system, an on-board / off-board charging device 30 can be set to charge the main battery 14 and the plug-in battery 12 when the truck is stationary. The energy management system controls the plug-in battery, the bidirectional DC / DC converter and the main battery. Depending on the power requirements of the forklift, there are different operating modes for the truck. In the reduced power operating mode, the power extracted from the main battery always provides a reserve for the additional load. In the power optimization operating mode, the additional power from the plug-in battery can be used.

[0021] There are also different kinds of charging modes for industrial trucks. In the plug-in battery charging mode, the control module controls the charging power for the main battery from the plug-in battery. In the plug-in battery charging mode, the plug-in battery is charged from the battery charger 30 while the plug-in battery is on board.

[0022] The advantage of the above industrial truck is that flexible charging can be performed while the truck is working. The plug-in battery can be standardized and modularized to be shared among different truck systems. In addition, the plug-in battery can be used in very different operating modes and charging modes to provide an overall very flexible system.

[0023] 10Energy Management System

[0024] 12 plug-in modular batteries

[0025] 14 Main battery

[0026] 16 lines

[0027] 18 lines

[0028] 20Motor controller including DC / AC controller

[0029] 22 Forklift Motor

[0030] 24 Auxiliary load

[0031] 26 Bidirectional DC / DC Converter

[0032] 28 DC / DC converter for auxiliary load

[0033] 30 Charging equipment

Claims

1. An industrial truck comprising at least one battery-powered drive, having a main battery (14) carried for power supply and also comprising a battery charger (30), the main battery (14) being able to be charged and discharged via the battery charger (30), characterized in that At least one insertion location is provided for one or more plug-in batteries (12), the insertion location having electrical contacts for connecting to a control module for each plug-in battery, the control module being configured to control at least two of the following operating modes and / or charging modes on the industrial truck: a reduced power operating mode in which the control module is operated to extract power from the main battery (14) at a rate that is less than the maximum output power of the main battery (14), a power optimization operating mode, in which the control module is operated to provide an amount of power such that at least one plug-in battery is additionally connected and supplies energy, - a plug-in battery charging mode, wherein the control module is operated to draw charging power from at least one plug-in battery as a main battery (14); and - a charger charging mode, in which at least one plug-in battery is charged from a battery charger (30).

2. The industrial truck according to claim 1, characterized in that When the industrial truck is stationary or traveling at a constant speed, the control module switches to the plug-in battery charging mode.

3. The industrial truck according to claim 1 or 2, characterized in that: The control module is activated during regenerative braking of the industrial truck to apply at least a portion of the generated power as charging power to the at least one plug-in battery.

4. The industrial truck according to any one of claims 1 to 3, characterized in that The control module also has an operating mode optimized for a determined operating period and drawing power from the at least one plug-in battery based on the state of charge (SOC) of the main battery (14).

5. Industrial truck according to one of claims 1 to 4, characterized in that The control module comprises a DC / DC (26) converter via which at least one plug-in battery is connected to the electrical network of the vehicle.

6. Industrial truck according to one of claims 1 to 5, characterized in that The value of the power extracted from the main battery in the power reduction operating mode is less than a limit value, which is selected so that in the event of additional power demand from another load, the maximum power demanded together with the power already extracted from the main battery remains less than the maximum output power of the main battery (14).

7. Industrial truck according to one of claims 1 to 6, characterized in that In the non-plug-in battery mode, the traction drive is fed by the main battery (14).

8. Industrial truck according to one of claims 1 to 7, characterized in that In the power optimization mode of operation, if the power demand exceeds the maximum output power of the main battery (14), the control module is controlled to draw power from the plug-in battery.

9. Industrial truck according to one of claims 1 to 8, characterized in that An auxiliary operating mode is provided in which the control module is controlled to draw power only from the plug-in battery (12).

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