Forklift and charging system

Abstract

To provide a forklift and a charging system that are equipped with charging devices allowing reduced manufacturing costs and easier maintenance.SOLUTION: Charging devices (in an embodiment, a small charging device and a large charging device) are provided with an eight-bit DIP switch, which can take values from 0 to 15. A manufacturer of a forklift is assigned to each value of the DIP switch. For example, manufacturers T, N, M, K, A, D, and the like are assigned to DIP switch values 1, 2, 3, 4, 5, 6, and the like, respectively. If a 16-bit DIP switch is used, up to 256 manufacturers can be distinguished. In particular, DIP switch value 0 indicates an all-purpose setting, and when the DIP switch of the charging devices is set to 0, charging is possible for forklifts of all manufacturers.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a forklift in which a power storage device is installed in a main body and driven, and a charging system for the forklift.

Background Art

[0002] A charging technique for correcting charging conditions according to the degree of deterioration of a secondary battery is known (for example, Patent Documents 1 and 2). The charging method disclosed in Patent Document 1 is applied to charging a lithium-ion secondary battery using a constant current constant voltage method (CCCV method). In this charging method, when the deterioration of the secondary battery progresses, the target value of the charging current or the upper limit value of the battery voltage is reduced, or the charging termination current value is increased. Thereby, generation of overcharging and excessive charging current is avoided according to the decrease in battery capacity.

[0003] The charging method disclosed in Patent Document 2 is applied to a power storage device of a hybrid construction machine, for example, a nickel-hydrogen battery or a lithium-ion battery. In this charging method, the power storage device is charged by the power generated by a motor generator driven by an engine. At the time of charging, an appropriate target charge amount is obtained according to the deterioration of the battery. Thereby, generation of overcharging and over-discharging can be prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, a constant-voltage charging method is applied to the charging of a lead-acid battery. In the constant-voltage charging method, charging is performed with a large current at the initial stage of charging. As charging progresses, the charging current automatically decreases, and at the end of charging, finishing charging is performed with a small charging current. During charging, the voltage between the terminals of the battery is monitored, and when the voltage between the terminals reaches a predetermined timer operation voltage, the timer operates. Charging ends when the timer operation time has elapsed since the start of the operation of the timer. When a lead-acid battery deteriorates, its internal resistance increases. If a lead-acid battery with advanced deterioration is charged under the same conditions as when it has not deteriorated, optimal charging cannot be performed.

[0006] An object of the present invention is to provide a forklift and a charging system equipped with a charging device that facilitates manufacturing costs and maintenance. Another object of the present invention is to provide a charging device that can charge a power storage device with advanced deterioration under appropriate conditions.

Means for Solving the Problems

[0007] The forklift of the present invention according to claim 1 is a forklift in which a power storage device is installed and which is driven by electric power supplied from the power storage device, wherein the power storage device and the charging device can be connected by a connection cable, the power storage device is charged by a current supplied from the charging device via the connection cable, and the charging device controls whether or not to charge the charging device based on identification information including the charging device and the forklift.

[0008] The charging system of the present invention according to claim 2 is a charging system including a forklift and a charging device, wherein the forklift is driven by electric power supplied from a power storage device to be installed, the power storage device and the charging device can be connected by a connection cable, the power storage device is charged by a current supplied from the charging device via the connection cable, and the charging device controls whether or not to charge the charging device based on identification information including the charging device and the forklift. [Effect of the Invention]

[0009] This makes the manufacturing cost and maintenance easier. Specifically, it is possible to easily determine whether the charging device is defective or the forklift is defective.

[0010] Since at least one of the timer operation voltage and the timer operation time is set according to the degree of deterioration of the power storage device, it is possible to perform charging under appropriate conditions even if the deterioration of the power storage device progresses. [Brief Description of the Drawings]

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0012] Example 1 (Reference): FIG. 1A shows a block diagram of a charging device 20 according to an example and an electric vehicle 30 charged by this charging device 20. Examples of the electric vehicle 30 include an electric forklift, an automatic guided vehicle (AGV), an electric cleaning robot, and the like.

[0013] The charging device 20 includes a charging circuit 21, a control device 22, an AC plug 23, a DC plug 24, a voltage sensor 25, and a current sensor 26. The electric vehicle 30 includes a power storage device 31, a DC plug 32, a relay 33, and an electrical load 35. The AC plug 23 of the charging device 20 is connected to a commercial power supply 15, and the DC plug 24 is connected to the DC plug 32 of the electric vehicle 30. A secondary battery such as a lead storage battery is used for the power storage device 31. Note that a nickel-metal hydride secondary battery, a lithium-ion secondary battery, an electric double layer capacitor, a lithium-ion capacitor, or the like may be used for the power storage device 31.

[0014] Power, for example, three-phase AC power, is supplied from the commercial power supply 15 to the AC plug 23. The charging circuit 21 includes a relay, a transformer, a rectifier, etc., and converts an alternating current into a direct current. The direct current (charging current) output from the charging circuit 21 is supplied to the power storage device 31 via the DC plug 24. The voltage sensor 25 measures the voltage between the terminals of the power storage device 31. The current sensor 26 measures the charging current of the power storage device 31. The measurement results by the voltage sensor 25 and the current sensor 26 are input to the control device 22. The control device 22 controls the relay of the charging circuit 21 based on the measurement results by the voltage sensor 25 and the current sensor 26.

[0015] During operation of the electric vehicle 30, power is supplied from the power storage device 31 mounted on the electric vehicle 30 to the electrical load 35 via the relay 33. When the power storage device 31 is being charged, the relay 33 is turned off.

[0016] Figure 1B shows a side view of a forklift as an example of the electric vehicle 30. This forklift is a so-called counterbalanced forklift configured to balance the vehicle body by mounting a weight at the rear of the vehicle body. The driver sits on the driver's seat 10 and operates an operating device 14 such as a lever. The front wheels 12 are arranged in front of the driver's seat 10, and the rear wheels 13 are arranged behind the driver's seat 10. The front wheels 12 are driving wheels, and the rear wheels 13 are steering wheels. The forks 11 arranged in front of the driver's seat 10 raise and lower the load. A connector terminal 34 is provided on the vehicle body for connecting a charging cable having a DC plug 32 (FIG. 1A). Further, a power storage device 31 is mounted on the vehicle body. The electrical load 35 (FIG. 1A) corresponds to a traveling electric motor that drives the front wheels 12 and a lifting electric motor that raises and lowers the forks 11.

[0017] The charging device 20 may be mounted on the forklift. In this case, a connector terminal for connecting a charging cable having an AC plug 23 (FIG. 1A) is provided on the forklift.

[0018] FIG. 2A shows a functional block diagram of the control device 22. The control device 22 includes an internal resistance measurement block 40, an arrival time measurement block 41, a timer operation time calculation block 42, a charge start / stop control block 43, and a finish charging time calculation table 44. These functions may be realized by an electronic circuit or a computer program.

[0019] FIG. 2B shows an example of the variation of the inter-terminal voltage v and the charging current i during charging. The horizontal axis represents the elapsed time, the left vertical axis represents the inter-terminal voltage v, and the right vertical axis represents the charging current i. In FIG. 2B, the inter-terminal voltage v is represented by a thick solid line, and the charging current i is represented by a thin solid line. The operation of the charging device 20 according to the embodiment will be described with reference to FIGS. 2A and 2B.

[0020] When the relay 27 of the charging circuit 21 is turned on by the charge start / stop control block 43 at the charge start time Ts, a charging current i starts to flow. The measured value Vs of the inter-terminal voltage v immediately before the charge start time Ts, the measured value Vs0 of the inter-terminal voltage v immediately after the charge start time Ts, and the measured value Is of the charging current i are input to the internal resistance measurement block 40. Based on the input measured values Vs, Vs0, and Is, the internal resistance Ri of the power storage device 31 (FIG. 1A) is calculated by the internal resistance measurement block 40. Specifically, the internal resistance Ri can be calculated by the following mathematical formula (1). It can be calculated.

[0021] Vs0 - Vs = Ri × Is ··· (1) As the deterioration of the power storage device 31 (FIG. 1A) progresses, the internal resistance Ri increases. The voltage sensor 25 and the current sensor 26 serve as deterioration sensors that measure physical quantities depending on the degree of deterioration of the power storage device 31. The voltage sensor 25 measures the inter-terminal voltage of the power storage device 31 and realizes part of the function of the deterioration sensor. The current sensor 26 measures the charging current of the power storage device 31 and realizes part of the function of the deterioration sensor. When charging starts at the charge start time Ts, as time elapses, the inter-terminal voltage v increases and the charging current i decreases. The arrival time measurement block 41 compares the current inter-terminal voltage v with a predetermined timer operation voltage Vt, and measures the elapsed time Tb from the charge start time Ts until the inter-terminal voltage v reaches the timer operation voltage Vt.

[0022] The timer operation time calculation block 42 calculates the timer operation time Ta based on the internal resistance Ri, the elapsed time Tb, and the finish charging time calculation table 44. The timer operation time Ta is calculated, for example, by the following mathematical formula (2).

[0023] Ta = A × Tb + C ··· (2)

[0024] Ta = A × Tb + C ··· (2) The finish charging time calculation table 44 defines the relationship between the internal resistance Ri and the coefficients A and C. The timer operation time calculation block 42 determines the values of the coefficients A and C by searching the finish charging time calculation table 44 using the internal resistance Ri as a key. When the values of the coefficients A and C are determined, the timer operation time Ta can be calculated from the coefficients A and C and the elapsed time Tb.

[0025] The charge start / stop control block 43 turns off the relay 27 at the time Te when the timer operation time Ta has elapsed since the time Tt when the inter-terminal voltage v reaches the timer operation voltage Vt. Thereby, the charging is stopped. When the charging current i stops flowing, the voltage drop due to the internal resistance Ri becomes 0V, so the inter-terminal voltage v drops by the amount of the voltage drop caused by the internal resistance Ri. Generally, the internal resistance Ri rapidly increases after passing the time Tt. For this reason, the decrease width of the inter-terminal voltage v at the charge end time Te is larger than the increase width of the inter-terminal voltage v at the charge start time Ts. At the end of charging, the open circuit voltage of the power storage device 31 (FIG. 1A) becomes almost equal to the rated value Vf of the full charge voltage. Note that the inter-terminal voltage v decreases with a time constant peculiar to the lead storage battery.

[0026] Referring to FIG. 3, the effects of the embodiments shown in FIGS. 1A to 2B will be described while comparing with a comparative example. FIG. 3 shows the time change of the inter-terminal voltage v. The inter-terminal voltage v shown by the thin broken line in FIG. 3 is the same as the time change of the inter-terminal voltage v shown in FIG. 2B.

[0027] In FIG. 3, the time variation of the inter-terminal voltage v in the state where the deterioration of the power storage device 31 has progressed is indicated by a thick solid line. As the deterioration of the power storage device 31 (FIG. 1A) progresses, the internal resistance Ri increases. As can be seen from the above formula (1), under the condition that the charging current i at the start time Ts of charging is the same, when the internal resistance Ri increases, the rising width of the inter-terminal voltage v increases. For this reason, the rising width of the inter-terminal voltage v at the start time Ts of charging becomes larger than the rising width of the inter-terminal voltage v in the state where no deterioration has occurred. Therefore, the measured value Vs1 of the inter-terminal voltage v immediately after the start time Ts of charging is higher than the measured value Vs0 in the state where no deterioration has occurred. As time passes, the inter-terminal voltage v rises.

[0028] Even during charging, the inter-terminal voltage v is higher than the inter-terminal voltage v indicated by the broken line. At time Tt1, the inter-terminal voltage v reaches the timer operation voltage Vt. From the start time Ts of charging, the elapsed time Tb1 until the inter-terminal voltage v reaches the timer operation voltage Vt is shorter than the elapsed time Tb when no deterioration has occurred.

[0029] In the comparative example, in the timer operation time calculation block 42 (FIG. 2A), the timer operation time Ta is calculated using the same values as the coefficients A and C used when no deterioration has occurred. Since the elapsed time Tb1 is shorter than the elapsed time Tb, the calculated timer operation time Tac becomes equal to or less than the value of the timer operation time Ta when no deterioration has occurred. Charging is stopped at time Tec when the timer operation time Tac has elapsed from time Tt1 when the timer operation voltage Vt is reached. Since the sum of the elapsed time Tb1 and the timer operation time Tac is shorter than the sum of the elapsed time Tb and the timer operation time Ta, charging ends before full charge is reached. Thus, when the charging time is set based on the measurement result of the inter-terminal voltage v affected by the internal resistance Ri, there is a case where full charge is not achieved.

[0030] In the embodiment, based on the internal resistance Ri, the coefficients A and C are determined by referring to the finish charging time calculation table 44 (FIG. 2A). In the finish charging time calculation table 44, the relationship between the internal resistance Ri and the coefficients A and C is defined such that the power storage device 31 is charged to almost a fully charged state. Specifically, the relationship between the internal resistance Ri and the coefficients A and C is defined such that as the internal resistance Ri increases, the timer operation time Ta becomes longer. For example, the coefficient A is constant and does not depend on the internal resistance Ri, and the coefficient C increases as the internal resistance Ri increases.

[0031] Therefore, the timer operation time Ta1 calculated when the deterioration has progressed is longer than the timer operation time Ta calculated when the deterioration has not progressed. The time Te1 when charging ends is later than the time Tec when charging ends in the comparative example. Therefore, even when the deterioration of the power storage device 31 has progressed and the internal resistance Ri has increased, it is possible to charge to a state close to full charge compared to the comparative example.

[0032] Next, referring to FIGS. 4 and 5, another embodiment will be described. Hereinafter, differences from the embodiment shown in FIGS. 1A to 3 will be described, and descriptions of the same configurations will be omitted.

[0033] FIG. 4 shows a functional block diagram of the charging device 20 according to the present embodiment. In the embodiment shown in FIG. 2A, the timer operation voltage Vt is a fixed value, and the timer operation time Ta is calculated based on the internal resistance Ri. In contrast, in the embodiment shown in FIG. 4, the timer operation voltage Vt is determined based on the internal resistance Ri.

[0034] The timer operation voltage calculation block 45 calculates the timer operation voltage Vt based on the internal resistance Ri and the operation voltage calculation table 46. In the operation voltage calculation table 46, the relationship between the internal resistance Ri and the timer operation voltage Vt is defined in advance. The elapsed time measurement block 41 measures the elapsed time Tb based on the timer operation voltage Vt obtained by the timer operation voltage calculation block 45.

[0035] The timer operation time calculation block 42 calculates the timer operation time Ta based on the elapsed time Tb. In this embodiment, the coefficients A and C used for calculating the timer operation time Ta are fixed values.

[0036] Referring to FIG. 5, the effects of the embodiment shown in FIG. 4 will be described while comparing with a comparative example. FIG. 5 shows the time change of the inter-terminal voltage v. The inter-terminal voltage v shown by the thin broken line in FIG. 5 is the same as the time change of the inter-terminal voltage v shown in FIG. 2B.

[0037] In FIG. 5, the inter-terminal voltage v in the state where the deterioration of the power storage device 31 (FIG. 1A) has progressed is shown by a thick solid line. When the deterioration progresses and the internal resistance Ri increases, the operation voltage calculation table 46 is defined so that the timer operation voltage Vt calculated by the timer operation voltage calculation block 45 becomes higher. In the state where the deterioration of the power storage device 31 has progressed, at the time Tt1 when the elapsed time Tb1 has elapsed from the start of charging, the inter-terminal voltage v reaches the timer operation voltage Vt when the deterioration has not progressed. In the case of the comparative example in which a fixed value is used as the timer operation voltage Vt, as described in FIG. 3, the charging ends at the time Tec before full charge is reached. In the embodiment, a voltage Vt1 higher than the timer operation voltage Vt when the deterioration has not progressed is used as the timer operation voltage. Therefore, the elapsed time Tb2 from the start time Ts of charging until the inter-terminal voltage v reaches the timer operation voltage Vt1 is longer than the elapsed time Tb1 until the inter-terminal voltage v reaches the timer operation voltage Vt. In the timer operation time calculation block 42 (FIG. 4), the timer operation time Ta2 is obtained. Charging ends at the time Te2 when the timer operation time Ta2 has elapsed from the time Tt2.

[0038]

[0039] ​​In the embodiment shown in FIG. 4, the time Tt2 at which the timer operation starts is later than the time Tt1 at which the timer operation starts in the comparative example. For this reason, the charging time from the charging start time Ts to the charging end time Te2 is longer than the charging time from the charging start time Ts to the charging end time Tec in the case of the comparative example. As a result, it becomes possible to charge to a state closer to full charge than in the comparative example. In the operation voltage calculation table 46, the relationship between the internal resistance Ri and the timer operation voltage Vt is defined so that a sufficient charging time for achieving a full charge state can be ensured even when the internal resistance Ri of the power storage device 31 increases.

[0040] With reference to FIG. 6, still another embodiment will be described. In the embodiments shown in FIGS. 1A to 3, the timer operation voltage Vt is set to a fixed value, and the coefficients A and C for calculating the timer operation time Ta are changed based on the internal resistance Ri. In the embodiments shown in FIGS. 4 to 5, the timer operation voltage Vt is changed based on the internal resistance Ri, and the coefficients A and C for calculating the timer operation time Ta are set to fixed values.

[0041] In the embodiment shown in FIG. 6, both the coefficients A and C for calculating the timer operation time Ta and the timer operation voltage Vt vary based on the internal resistance Ri. Specifically, the timer operation voltage calculation block 45 calculates the timer operation voltage Vt based on the internal resistance Ri and the operation voltage calculation table 46. Further, the timer operation time calculation block 42 calculates the timer operation time Ta based on the internal resistance Ri and the finish charging time calculation table 44. In the embodiment shown in FIG. 6, the degree of freedom in setting the charging conditions can be increased as compared with the embodiments shown in FIGS. 1A to 3 and the embodiments shown in FIGS. 4 to 5.

[0042] With reference to FIG. 7, still another embodiment will be described. Hereinafter, differences from the embodiments shown in FIGS. 1A to 3 will be described, and descriptions of the same configurations will be omitted. In the embodiments shown in FIGS. 1A to 3, the internal resistance Ri was obtained based on the measured values of the terminal voltage v and the charging current i immediately before and after the charging start time Ts. In the embodiment shown in FIG. 7, the internal resistance Ri is obtained during the charging period.

[0043] In the upper part of FIG. 7, the time change of the inter-terminal voltage v is shown, and in the lower part, the time change of the charging current i is shown. During the charging period from the charging start time Ts to the time Tt when the inter-terminal voltage v reaches the timer operating voltage Vt, the supply of the charging current i is temporarily stopped at least once. FIG. 7 shows an example in which the supply of the charging current i is stopped three times during the charging period.

[0044] When the charging current i becomes 0, the voltage drop due to the internal resistance Ri of the power storage device 31 (FIG. 1A) does not occur, so the inter-terminal voltage v drops by the amount of the voltage drop that was occurring due to the internal resistance Ri. When the supply of the charging current i is resumed, the inter-terminal voltage v rises by the amount of the voltage drop. The internal resistance Ri can be calculated by measuring the magnitudes I1, I2, I3 of the charging current i and the fluctuation widths V1, V2, V3 of the inter-terminal voltage v at the time when the supply of the charging current i is resumed.

[0045] When the supply of the charging current i is stopped a plurality of times, the internal resistance Ri is calculated each time the supply of the charging current i is stopped. In this case, the average value of the plurality of calculated internal resistances Ri is adopted as the internal resistance Ri of the current power storage device 31 (FIG. 1A). The processing after the internal resistance Ri is obtained is the same as any of the embodiments of FIGS. 1A to 3, the embodiments of FIGS. 2 to 5, and the embodiment of FIG. 6, and charging is performed.

[0046] When the charging current i becomes 0, the inter-terminal voltage v drops with a certain time constant. The time for which the supply of the charging current i is stopped is preferably made sufficiently longer than this time constant. For example, it is preferable to stop the supply of the charging current i for 10 seconds or more. Thereby, the magnitude of the voltage drop due to the internal resistance Ri can be accurately measured.

[0047] In the embodiments shown in FIGS. 1A to 3, the embodiments shown in FIGS. 4 to 5, and the embodiment shown in FIG. 6, the internal resistance Ri of the power storage device 31 (FIG. 1A) was measured before and after the charging start time Ts. In the embodiment shown in FIG. 7, the internal resistance of the power storage device 31 was measured during the charging period. As another method, the internal resistance Ri may be measured at the end of charging. For example, the internal resistance Ri can be calculated based on the charging current i immediately before the time Te (FIG. 2B) when charging ends and the fluctuation range of the terminal voltage v at the time Te. The calculated value of the internal resistance Ri is used when determining the charging conditions for the next charging. As described above, the present invention has been described along with the embodiments, but the present invention is not limited to these. For example, it is obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

[0048] Important Embodiment: As basic components, for the forklift configured as described above and the charging system for charging the forklift, a novel and inventive technical idea will be detailed below.

[0049] The applicant of the present application manufactures, sells, and supplies a charging system including a lithium-ion battery (a power storage device installed in a forklift) and a charging device mounted on a forklift to a plurality of manufacturers (for example, Company T, Company N, Company M, Company K, Company A, Company D, etc.).

[0050] Each company's forklift is driven by the power supplied from the power storage device. The power storage device and the charging device can be connected by a connection cable. The power storage device is charged by the current supplied from the charging device via the connection cable. Basically, with the power storage device installed in the forklift, power is stored from the charging device into the power storage device. Note that it is also possible to charge the power storage device individually with the power storage device removed from the forklift during charging.

[0051] The charging device has multiple corresponding voltages of 24V, 36V, 48V, 72V, 80V, and 115V. Charging for 24V, 36V, and 48V can be done with the same small charging device. Similarly, charging for 72V, 80V, and 115V can be done with the same large charging device. That is, the small charging device is for three voltages of 24V, 36V, and 48V, and the large charging device is for three voltages of 72V, 80V, and 115V. Naturally, it can also support other voltages.

[0052] Let the product of Company T be Forklift T, the product of Company N be Forklift N, the product of Company M be Forklift M, the product of Company K be Forklift K, the product of Company A be Forklift A, the product of Company D be Forklift D, and the product of any company X be Forklift X (X is any value).

[0053] The charging device (in the embodiment, a small charging device and a large charging device) is provided with an 8-bit dip switch, which can take values from 0 to 15. Corresponding to the value of this dip switch, a forklift manufacturer is assigned. For example, the value 1 of the dip switch is assigned to Company T, the value 2 is assigned to Company N, the value 3 is assigned to Company M, the value 4 is assigned to Company K, the value 5 is assigned to Company A, the value 6 is assigned to Company D... If a 16-bit dip switch is used, 256 companies can be distinguished. In particular, the value 0 of the dip switch means all-mighty. When the value of the dip switch of the charging device is set to 0, it can charge forklifts of all manufacturers.

[0054] Similarly, the power storage device stores a manufacturer identification code in the memory. The value of the manufacturer identification code of the power storage device of Company T is assigned as 1, the value 2 is assigned to Company N, the value 3 is assigned to Company M, the value 4 is assigned to Company K, the value 5 is assigned to Company A, the value 6 is assigned to Company D... The manufacturer identification code is stored in a memory such as a ROM, but a dip switch can also be provided to identify it by its value.

[0055] The charging device and the energy storage device of each company are connected by a connection cable. That is, the energy storage device and the charging device can be connected by a connection cable, and the energy storage device is charged by the current supplied from the charging device via the connection cable. Naturally, the charging device, the energy storage device, and the connection cable of Company T have the logo of Company T printed on them, and each company can be distinguished. Similarly, Company N has the logo of Company N printed on it, and the same is true for other companies.

[0056] When the identification information of its own charging device matches the identification information on the energy storage device side (the identification information consisting of the charging device and the forklift), the charging device determines that charging is permitted and starts charging. On the other hand, if they do not match, charging is not performed. That is, the charging device controls whether to charge the charging device based on the identification information consisting of the charging device and the forklift. Also, while starting charging when it is determined that charging is possible, charging is not performed when it is determined that charging is impossible. Note that these charging devices, the energy storage device on which the forklift is placed, and the connection cable are common devices for each company. For example, when connecting the charging device of Company T and the energy storage device provided by the forklift of Company N with the connection cable of Company M, charging cannot be performed because the identification information of the charging device and the forklift is different. However, if the value of the dip switch of the charging device of Company T is set to 0, charging can be performed without problems. This facilitates manufacturing costs and maintenance. Specifically, in the case of Company T, when there is an abnormality in the charging of the charging device of Company T and the forklift of Company T, if the maintenance worker brings an all - mighty charging device (the value of the dip switch is 0) and an all - mighty connection cable to the site and connects them to the forklift of Company T, it is possible to determine whether the charging device of Company T is defective or the forklift of Company T is defective according to whether charging is possible or not.

Explanation of Signs

[0057] 10 Driver's seat 11 Fork 12 Front wheel 13 Rear wheel 14 Operator 15 Commercial power supply 20 Charging device 21 Charging Circuit 22 Control Device 23 AC Plug 24 DC Plug 25 Voltage Sensor 26 Current Sensor 27 Relay 30 Electric Vehicle 31 Energy Storage Device 32 DC Plug 33 Relay 35 Electrical Load 40 Internal Resistance Measurement Block 41 Arrival Time Measurement Block 42 Timer Operating Time Calculation Block 43 Charging Start / Stop Control Block 44 Finish Charging Time Calculation Table 45 Timer Operating Voltage Calculation Block 46 Operating Voltage Calculation Table

Claims

1. A forklift in which a power storage device is installed and which is driven by electric power supplied from the power storage device, wherein the power storage device and the charging device can be connected by a connection cable, the power storage device is charged by a current supplied from the charging device via the connection cable, and the charging device controls whether to charge the charging device based on identification information including the charging device and the forklift, characterized by the forklift.

2. A charging system comprising a forklift and a charging device, wherein the forklift is driven by electric power supplied from an installed power storage device, the power storage device and the charging device can be connected by a connection cable, the power storage device is charged by a current supplied from the charging device via the connection cable, and the charging device controls whether to charge the charging device based on identification information including the charging device and the forklift, characterized by the charging system.

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