Electrically powered industrial truck equipped with a safety locking function

Abstract

An electrically powered industrial truck (10) comprises: - actuator means (16, 17) configured to perform primary functions of the industrial truck; - an electricity storage system (18) configured to supply the actuator means (16, 17) with electricity; - control means (20) configured to control the actuator means (16, 17); said control means (20) being configured to acquire a state of health, SOH, of the electricity storage system (18). The control means (20) are configured to compare the acquired state of health, SOH, of the electricity storage system (18) with a pre-established threshold and to determine whether the state of health, SOH, of the acquired electricity storage system (18) is below the pre-established threshold; said control means (20) being further configured to prevent the supply of electricity from the electricity storage system (18) to the actuator means (16, 17) when, based on the comparison, the state of health, SOH, is determined to be below the pre- established threshold.

Description

[0001] TITLE: Electrically powered industrial truck equipped with a safety locking function

[0002] Field of the invention

[0003] The present invention relates to an electrically powered industrial truck, in particular equipped with a safety locking function.

[0004] Technical background

[0005] It is known in the art to make industrial trucks equipped with material handling means, such as a forklift truck, which can be used on an industrial site, a warehouse, a port or the like. Recently, electrically powered industrial trucks have spread, i.e. equipped with a battery capable of powering the main functions of the industrial truck such as locomotion and / or material handling.

[0006] Over time, as a result of repeated work cycles, the battery of an industrial truck deteriorates, reducing its capacity, reducing the maximum energy that can be stored in the battery. This leads to reduced performance, for example due to a reduction in the time of use of the industrial truck between one recharging and the next one.

[0007] Systems are known that aim to adjust the allocation of power supplied by the battery as a function of an ageing state of the battery. These systems aim to adjust the power to meet a pre-established expectation of battery life. However, the inventors have observed that, most frequently, the industrial truck users are willing to maintain reduced performance of the industrial truck even for extended periods that go beyond the expected life of the battery, without replacing the battery for cost reasons, or because the industrial truck is assigned to a function that requires lower performance (both in terms of power delivered and duration of a work cycle that can be performed with a recharge). In this case, the state of health (SOH) of the battery can be excessively reduced and give rise to dangerous situations. For example, in the case of a lithium-ion battery (or lithium battery), cells with reduced SOH have lower values of thermal runaway temperature; there is a risk under these circumstances that dendrite formations penetrate the separating membrane of the battery cell, causing a short circuit. This situation can lead to a high risk of fire and dangers for the user of the industrial truck.

[0008] The problem can be even all the more accentuated when the energy sources are fully integrated with the machine and not interchangeable (as in a more common use). In these cases, if the life of the machine exceeds that of the battery, the probability of more dangerous situations connected to a too low SOH is greater.

[0009] Summary of the invention

[0010] It is an object of the present disclosure to obviate the above-mentioned problems, in particular to increase the safety in the use of an electrically powered industrial truck. In light of this object, the present disclosure provides an electrically powered industrial truck comprising:

[0011] -actuator means configured to perform primaryfunctionsof the industrial truck; - an electricity storage system configured to supply the actuator means with electricity;

[0012] - control means configured to control the actuator means;

[0013] said control means being configured to acquire a state of health, SOH, of the electricity storage system,

[0014] characterized in that the control means are configured to compare the acquired state of health, SOH, of the electricity storage system with a pre-established threshold and to determine whether the acquired state of health, SOH, of the electricity storage system is below the pre-established threshold;

[0015] said control means being further configured to prevent the supply of electricity from the electricity storage system to the actuator means when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

[0016] Preferably, the electricity storage system includes a lithium battery.

[0017] Preferably, the pre-established threshold is comprised in a range between 40% and 60%, preferably between 45% and 55%, more preferably between 48% and 52%, or about 50%.

[0018] Preferably, the actuator means comprise one or more electric motors for the locomotion of the industrial truck.

[0019] Preferably, the actuator means comprise one or more actuators configured to actuate material handling means of the industrial truck.

[0020] Preferably, the material handling means include a substantially vertical upright and a load lifting device configured to slide along the upright underthe action of the one or more actuators.

[0021] Preferably, the control means are configured to preclude the switching on of the industrial truck when the state of health, SOH, is determined to be below the pre-established threshold.

[0022] Preferably, the control means are configured to immobilize the industrial truck when the state of health, SOH, is determined to be below the pre-established threshold.

[0023] Preferably, the control means are configured to completely preclude the locomotion of the industrial truck and the handling of the material handling means when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

[0024] Preferably, the state of health, SOH, of the electricity storage system is determined based on one or more of the following parameters: the maximum residual capacity of the electricity storage system, the total cumulative energy output by the electricity storage system over its life cycle, an internal impedance of the electricity storage system, a number of charging / discharging cycles of the electricity storage system, the age of the electricity storage system.

[0025] Preferably, the industrial truck further comprises a user interface, wherein the control means are configured to enable the powering of the user interface when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold, said control means being further configured to control the user interface so as to emit a safety notification to the user when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold. According to one aspect, there is provided a method for controlling an electrically powered industrial truck comprising:

[0026] acquiring a state of health, SOH, of electricity storage system of the industrial truck,

[0027] comparing the acquired state of health, SOH, of the electricity storage system with a pre-established threshold and determining whether the state of health, SOH, of the acquired electricity storage system is below the pre-established threshold;

[0028] preventing the supply of electricity from the electricity storage system to actuator means of the industrial truck when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

[0029] In a preferred embodiment, the method for controlling an electrically powered industrial truck comprises any step described in the present disclosure as performed by the control means of the industrial truck.

[0030] According to one aspect, a computer program is provided which, when executed by a processor of the computer, causes the processor to perform the operations of a method according to the present disclosure.

[0031] Brief description of the drawings

[0032] The present invention will be illustrated with reference to exemplary embodiments described with reference to the accompanying drawings.

[0033] In the drawings:

[0034] - figure 1 illustrates a view of an industrial truck according to the present disclosure;

[0035] -figure 2 illustrates a schematicview ofthe control means, the electricity storage system and the actuators of the industrial truck;

[0036] -figure 3 illustrates a view of a process implemented by the control means ofthe industrial truck;

[0037] -figure 4 illustrates a view of a further process implemented by the control means of the industrial truck; -figure 5 illustrates a schematic view of an implementation of the control means.

[0038] Detailed description

[0039] With reference to the figures, an electrically driven, or electrically powered, industrial truck 10 according to the present disclosure is shown in figure 1. The industrial truck 10 may for example be a forklift truck. The industrial truck 10 could advantageously be a counterbalanced truck. Another type of industrial truck could also be realized according to the present disclosure. In general, the industrial truck may include material handling means; the material handling means may for example include an upright 21 along which a material gripping device 22, such as a fork (as shown in the figure), a gripper, or other known devices, can slide in a substantially vertical direction. In general, the material handling means 12 may be configured to move a load relative to a frame 11 of the industrial truck, for example a frame associated with the axles of the industrial truck. In other words, the material handling means 12 can move a load while the industrial truck 10 is not translating.

[0040] For example, the industrial truck 10 can be used in industrial sites, warehouses, ports, airports, logistic hubs or the like. The electrically powered industrial truck 10 can be of the hybrid type (i.e. equipped with a traction or drive system that includes at least one electric motor and at least one combustion engine), or it could be completely electric (therefore with a traction system that does not include a combustion engine and instead includes only one or more electric motors). The electrically powered industrial truck 10 is provided with an electrical electricity storage system 18 intended to supply electrical power to a primary function of the industrial truck, such as for example the locomotion function and / or the material handling function.

[0041] In a preferred embodiment, the electricity storage system 18 is integrated into the industrial truck irremovably from the industrial truck. The electricity storage system 18 may be housed in a frame 11 of the industrial truck 10. Preferably, the electricity storage system 18 is positioned below a user station 13, made for example in the form of a booth as depicted in figure l.The present disclosure may also be applied to the case where the electricity storage system 18 is removable from the industrial truck (e.g. for replacement), e.g. via a side opening in the truck frame.

[0042] Wheels, for example 3 or 4 wheels, are mounted on the frame 11. Advantageously, the wheels are arranged on two axles, one front and one rear of the industrial truck, although other configurations are also possible.

[0043] Referring to Figure 2, the industrial truck 10 comprising the electricity storage system 18, operating means (or actuator means) 16-17 which can be powered by the electricity storage system 18, control means 20, and a user interface 15 is schematically shown. The control means 20 (which in the present disclosure may also be referred to as control unit 20) are connected with the actuator means 16, 17 and the user interface 15 so as to be able to send signals (e.g. control signals to the actuator means) and receive signals (e.g. command signals input by the driver of the industrial truck via the user interface 15).

[0044] The electricity storage system 18 may comprise, or consist of, any battery system or electrical electricity storage system, such as for example a lithium, lead acid, or other types of battery, or a combination of a plurality of battery modules or packs of any type according to the known art. Preferably, in the present disclosure, the electricity storage system comprises a lithium battery (or lithium-ion battery).

[0045] The actuator means 16, 17 (which in the present disclosure may also be referred to as one or more actuator units 16, 17) are configured to perform primary functions of the industrial truck, such as the locomotion function and / or the material handling function. The actuator means 16 may include a locomotion system of the industrial truck; the actuator means 17 include a load handling system. In particular, the actuator means 16 preferably comprise one or more electric motors for the locomotion of the industrial truck. Each wheel or, alternatively, each axle could be equipped with an electric motor for locomotion. Alternatively, a single electric motor could be provided for locomotion of the industrial truck.

[0046] In one embodiment, the actuator means 17 comprise one or more actuators configured to actuate material handling means 12 of the industrial truck 10. For example, the actuator means may include electric or electro-hydraulic drives for moving the handling (or lifting) device 22 of the load 12 along the upright 21. The actuator means may also include an electric or electro-hydraulic drive for swinging the upright 21 about a substantially horizontal axis. In a preferred embodiment, the actuator means 16, 17 are controlled by the control means 20. The electricity storage system 18 is configured to supply the actuator means 16, 17 with electricity, for example by means of suitable power wiring.

[0047] The user interface 15 may include one or more of the following components: a touchscreen, a keypad, a steering wheel, a joystick, a touchpad, an acoustic emitter, a microphone, or the like. The user interface 15 is configured to receive in input commands from the user and / or to emit notifications to the user. The user interface 15 may be powered by the electricity storage system 18 or by a dedicated auxiliary power system (not shown in the figure).

[0048] The control means 20 are configured to acquire a state of health, SOH, of the electricity storage system 18. The control means 20 may acquire the SOH from a management system of the electricity storage system 18. The SOH can be determined by the control means 20 using known logic, on the basis of measured electrical quantities relating to the electricity storage system 18 or on the basis of time and / or consumption meters and / or a number of recharges. The state of health, SOH, of the electricity storage system may be determined in different ways by the control means 20 or by a management system of the electricity storage system. According to one embodiment, the SOH is based on (i.e. may be determined based on) one or more of the following parameters: the maximum residual capacity of the electricity storage system, the total cumulative energy output by the electricity storage system over its life cycle, an internal impedance of the electricity storage system, a number of charging / discharging cycles of the electricity storage system, the age of the electricity storage system.

[0049] The control means 20 are configured to compare the acquired state of health, SOH, with a pre-established threshold and to determine whether the state of health, SOH, of the electricity storage system 18 is below the pre-established threshold. This threshold is determined in order to identify a state of health below which there is a danger in case of use of the electricity storage system. For example, the pre-established threshold is comprised in a range between 40% and 60%, preferably between 45% and 55%, more preferably between 48% and 52%, or about 50%. The value of SOH is expressed in percentage terms to indicate the current value with respect to an ideal value; for example, in the case where the SOH is based on (or corresponds to) the value of the maximum storable energy, the percentage indicates the ratio of the current maximum storable energy value to the value of the maximum storable energy of the electricity storage system at the time of its production (or at the time of BoL, "Beginning of Life"). The value of the threshold may depend on the type of cell used in the electricity storage system. The inventors have identified values of the pre-established threshold that are particularly suitable for the case of cells of a lithium-ion battery. The pre-established threshold value is preferably below an SOH value that corresponds to an End of Life (EoL) value of the battery. For example, the SOH value corresponding to the end of life (EoL) of the battery could be in the range 70%-80%. When the SOH is below the pre-established threshold, there is a risk when using the electricity storage system 18, for example a risk associated with a possible short circuit due to dendrite formations that can penetrate the membrane of a lithium cell.

[0050] The control means 20 are configured to prevent the supply of electricity from the electricity storage system 18 to the actuator means 16, 17 when the state of health, SOH, is determined to be below the pre-established threshold. For example, if the SOH is determined to be below a threshold of 50%, the control means 20 prevent the power supply the electricity storage system 18 to the actuators 16, 17, by actually completely preventing the actuation of the actuator means. Preferably, the control means 20 prevent any movement of the industrial truck, in particular both a translation (locomotion) and a movement of the material handling means 12. In one embodiment, the control means 20 are configured to preclude the switching on of the industrial truck 10 when the state of health, SOH, is determined to be below the pre-established threshold.

[0051] In one embodiment, when the state of health is determined to be below the pre-established threshold, the control means 20 may allow the user interface 15 and / or electronic control boards of the industrial truck to be powered, for example to allow an error or alarm message to be displayed via the user interface 15. In this case, only the actuators 16, 17 that move the industrial truck can be disconnected.

[0052] Alternatively, access to the control means 20 and to the state of the industrial truck 10 and / or the electricity storage system 18 could only be allowed through a "service tool", for example by connecting the industrial truck to a reader device suitable for diagnosing the state of the machine.

[0053] The control means 20 can be powered by the electricity storage system 18 or by a dedicated auxiliary power supply system (not shown in the figure).

[0054] According to a possible operation of the industrial truck 10, the control means 20 are configured to perform the following steps, as shown in figure 3:

[0055] Sil: in this step the control means 20 are started;

[0056] S12: following the switching on, the control means 20 acquire a current value SOH relating to the electricity storage system 18;

[0057] S13: subsequently the control means 20 compare the acquired SOH with a pre-established threshold;

[0058] S14: in this step the control means 20 determine whether the acquired SOH is below or above the pre-established threshold; if SOH is not below the pre-established threshold, the truck can operate normally and energy is supplied to the main functions of the industrial truck through the system 18; further checks S12-S13 can be carried out on the SOH repeatedly, for example at regular intervals of time; if SOH is below the threshold, it is continued with step S15.

[0059] S15:the industrial truck 10 is secured by disconnecting the primary functions, for example of locomotion and movement of a load; for example, this step can be achieved by disconnecting the actuators 16 for locomotion and the actuators 17 for material handling, so that the electricity storage system 18 does not supply energy to these actuators.

[0060] The comparison of the SOH with a threshold can take place at each start (switching on) of a truck; alternatively, the comparison of the SOH with the threshold can take place at the end of a work cycle when the industrial truck is switched off. Preferably, the comparison of the SOH with the threshold can take place only once during a work cycle. If the control means determine that SOH is below the threshold during a work cycle (for example corresponding to a work cycle between one recharging and the next one), they can preclude the switching on of the industrial truck in a subsequent work cycle. Alternatively, if the control means determine that SOH is below the threshold during a work cycle (e.g. corresponding to a work cycle between one recharging and a next one), it may prevent a subsequent recharge of the electricity storage system.

[0061] Figure 4 shows a further embodiment of the present invention in terms of actions that the control means 20 of the industrial truck 10 are configured to perform. Steps S11-S14 correspond to steps S11-S14 already described with reference to Figure 3. In step S15', the control means are configured to immobilize the industrial truck when it is determined that the acquired SOH is below the threshold. For example, this step may be accomplished by disconnecting the actuators 16 for locomotion and the actuators 17 for material handling. In step S15', the control means keep the user interface 15 of the industrial truck, for example a touchscreen, powered. At the next step S16, the control means control the user interface 15 so as to emit a safety notification to the user. The safety notification may for example include a message displayed on a touchscreen that is part of the user interface 15, or it could be an acoustic signal emitted via the user interface 15. The safety notification may include a message indicating the danger that would arise if the battery were used further. The safety notification may include a message to replace the battery.

[0062] Figure 5 shows a possible implementation of the control means 20. In one embodiment, the control means 20 include a processor 42, a memory 43, and an input / output (I / O) interface 41. The processor is configured to execute control software stored on the memory 43 to perform any of the functions of the control unit 20 as described above. When executing the control software, the processor 42 receives as input information received from sensors of the industrial truck or user commands via the input / output (I / O) interface 41 and emits control signals to the actuators 16-17 also using the input / output (I / O) interface 41. Still other possible implementations of the control unit may be devised, including for example a plurality of distributed processors or the like. The control means 20 can be realized with a control device, for example connected to buses on board the machine. However, even a plurality of distributed control devices (or control boards) could perform the above-described functions of the control means. For example, one or more functions described above as being performed by the control means could be performed by a management system of the electricity storage system.

[0063] While various exemplary embodiments of the present invention have been described, it is intended that they have been presented by way of non-limiting example. It is apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made in this context. Therefore, the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only on the basis of the following claims and equivalents thereof.

Claims

CLAIMS1. An electrically powered industrial truck (10) comprising:-actuator means (16, 17) configured to perform primary functions of the industrial truck;-an electricity storage system (18) configured to supply the actuator means (16, 17) with electricity;-control means (20) configured to control the actuator means (16, 17); said control means (20) being configured to acquire a state of health, SOH, of the electricity storage system (18),characterized in that the control means (20) are configured to compare the acquired state of health, SOH, of the electricity storage system with a pre-established threshold and to determine whetherthe acquired state of health, SOH, of the electricity storage system is below the pre-established threshold;said control means (20) being further configured to prevent the supply of electricity from the electricity storage system (18) to the actuator means (16, 17) when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

2. An industrial truck according to claim 1, wherein the electricity storage system (18) includes a lithium battery, preferably integrated into the industrial truck so as not to be removable from the industrial truck.

3. An industrial truck according to claim 1 or 2, wherein the pre-established threshold is comprised in a range between 40% and 60%, preferably between 45% and 55%, more preferably between 48% and 52%, or about 50%.

4. An industrial truck according to one of the preceding claims, wherein the value of the pre-established threshold is below an SOH value that corresponds to an end-of-life value, EoL, of the electricity storage system (18).

5. An industrial truck according to one or more of the preceding claims, wherein the actuator means (16, 17) comprise one or more electric motors for the locomotion of the industrial truck, and / or one or more actuators configured to actuate material handling means (12) of the industrial truck.

6. An industrial truck according to claim 5, wherein the control means (20) are configured to completely preclude the locomotion of the industrial truck and the movement of the material handling means when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

7. An industrial truck according to one of the preceding claims, further comprising a user interface (15), wherein the control means (20) are configured to enable the powering of the user interface (15) when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold, said control means being further configured to control the user interface (15) so as to emit a safety notification to the user when, based on the comparison, the state of health, SOH, is determined to be below the pre-established threshold.

8. An industrial truck according to one or more of the preceding claims, wherein the control means (20) are configured to preclude the switching on of the industrial truck (10) when the state of health, SOH, is determined to be below the pre-established threshold.

9. An industrial truck according to one or more of the preceding claims, wherein the control means (20) are configured to immobilize the industrial truck (10) when the state of health, SOH, is determined to be below the pre-established threshold.

10. An industrial truck according to one or more of the preceding claims, wherein the state of health, SOH, of the electricity storage system is based on one or more of the following parameters: the maximum residual capacity of the electricity storage system, the overall cumulative energy output by the electricity storage system in its life cycle, an internal impedance of the electricity storage system, a number of charging / discharging cycles of the electricity storage system, and the age of the electricity storage system.

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