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 truck that is driven by a power storage device installed in its main body, and a charging system for the forklift truck. [Background technology]

[0002] Charging techniques that correct charging conditions according to the degree of deterioration of a secondary battery are 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 (CCCV) method. In this charging method, as deterioration of the secondary battery progresses, the target value of the charging current or the upper limit of the battery voltage is reduced, or the charge cut-off current value is increased. This prevents overcharging and the generation of excessive charging current according to a 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, such as a nickel-metal hydride battery or a lithium-ion battery. In this charging method, the power storage device is charged with electric power generated by a motor generator driven by the engine. During charging, an appropriate target charge amount is determined according to the battery's deterioration. This makes it possible to prevent overcharging and over-discharging. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-222427 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-119761 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, the quasi-constant voltage charging method is used to charge lead-acid batteries. In the quasi-constant voltage charging method, charging is performed with a large current at the beginning of charging. As charging progresses, the charging current automatically decreases, and at the end of charging, a finish charge is performed with a small charging current. The battery terminal voltage is monitored during charging, and when the terminal voltage reaches a predetermined timer operating voltage, the timer operates. Charging ends when the timer operating time has elapsed since the start of timer operation. As lead-acid batteries deteriorate, their internal resistance increases. If a deteriorated lead-acid battery is charged under the same conditions as when it was not deteriorated, optimal charging cannot be achieved.

[0006] The present invention aims to provide a forklift and charging system equipped with a charging device that can be manufactured at low cost and easily maintained. Another object of the present invention is to provide a charging device that can charge even a deteriorated power storage device under appropriate conditions. [Means for solving the problem]

[0007] In order to achieve the above object, the forklift of the present invention according to claim 1 is a forklift that is installed with a power storage device and is driven by power supplied from the power storage device, , charging the storage device the power storage device can be connected to a charging device by a connection cable, and the power storage device is charged by a current supplied from the charging device via the connection cable; the storage device stores storage device side identification information for identifying a manufacturer of the forklift, the charging device has a setting means for setting the identification information, and the charging device side identification information set by the setting means can be set to identification information that can take multiple values ​​for identifying the manufacturer of the forklift and an almighty value that allows charging of forklifts of all manufacturers, The charging device is The aforementioned charging device side knowledge Other information and before storage device Okiside knowledge Compare with other information, When the charging device side identification information matches the storage device side identification information, charging of the storage device is permitted, and when they do not match, charging of the storage device is prohibited. Control to prohibit, and further, The almighty value is set as the charging device side identification information When in a specific setting state, Regardless of the value of the storage device side identification information, It is characterized by performing control to permit charging. [Effects of the Invention]

[0009] This reduces manufacturing costs and simplifies maintenance. Specifically, it is possible to easily determine whether the charging device or the forklift is faulty.

[0010] At least one of the timer operating voltage and the timer operating time is set according to the degree of deterioration of the power storage device, so that even if the power storage device is severely deteriorated, it is possible to charge the power storage device under appropriate conditions. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1A is a block diagram of a charging device according to an embodiment and an electric vehicle charged by the charging device, and FIG. 1B is a side view of a forklift charged by the charging device according to an embodiment. [Figure 2] FIG. 2A is a functional block diagram of the control device, and FIG. 2B is a graph showing an example of fluctuations in terminal voltage and charging current during charging. [Figure 3] FIG. 3 is a graph showing an example of fluctuations in terminal voltage and charging current during charging in the embodiment shown in FIG. 2A, in comparison with a comparative example. [Figure 4] FIG. 4 is a functional block diagram of a charging device according to another embodiment. [Figure 5] FIG. 5 is a graph showing an example of fluctuations in terminal voltage and charging current during charging in the embodiment shown in FIG. 4, in comparison with a comparative example. [Figure 6] FIG. 6 is a functional block diagram of a charging device according to yet another embodiment. [Figure 7] FIG. 7 is a graph showing an example of fluctuations in terminal voltage and charging current during charging in yet another embodiment. [Figure 8] 10 is a graph showing an example of fluctuations in terminal voltage and charging current during charging in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0013] The charging device 20 includes a charging circuit 21, a control device 22, an AC plug 23, a DC plug 24, and a power supply. The charging device 20 includes a pressure 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 electric load 35. The AC plug 23 of the charging device 20 is connected to a commercial power source 15, and the DC plug 24 is connected to a DC plug 32 of the electric vehicle 30. The power storage device 31 is, for example, a secondary battery such as a lead storage battery. It should be noted that the power storage device 31 may be a nickel-metal hydride secondary battery, a lithium-ion secondary battery, an electric double layer capacitor, a lithium-ion capacitor, a A capacitor or the like may also be used.

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

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

[0016] FIG. 1B shows a side view of a forklift as an example of an electric vehicle 30. This forklift is a so-called counter-load forklift, which is configured to balance the vehicle body by mounting a weight on the rear of the vehicle body. A driver sits in a driver's seat 10 and operates a control device 14 such as a lever. Front wheels 12 are located in front of the driver's seat 10, and rear wheels 13 are located behind the driver's seat 10. The front wheels 12 are driving wheels, and the rear wheels 13 are steering wheels. Forks 11, located in front of the driver's seat 10, lift and lower cargo. A connector terminal 34 for connecting a charging cable having a DC plug 32 (FIG. 1A) is provided on the vehicle body. Furthermore, an electricity storage device 31 is mounted on the vehicle body. An electric load 35 (FIG. 1A) corresponds to an electric motor for driving the front wheels 12 and an electric motor for raising and lowering the forks 11.

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

[0018] 2A shows a functional block diagram of the control device 22. The control device 22 includes an internal resistance measurement block 40, a reaching time measurement block 41, a timer operation time calculation block 42, a charge start / stop control block 43, and a top-up charge time calculation table 44. These functions may be realized by electronic circuits or by computer programs.

[0019] FIG. 2B shows an example of fluctuations in terminal voltage v and charging current i during charging. The horizontal axis represents elapsed time, the left vertical axis represents terminal voltage v, and the right vertical axis represents charging current i. In FIG. 2B, the 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 this embodiment will be described with reference to FIGS. 2A and 2B.

[0020] At the charging start time Ts, the charging start / stop control block 43 turns on the relay 27 of the charging circuit 21, and the charging current i starts to flow. The measured value Vs of the inter-terminal voltage v immediately before the charging start time Ts, and the measured value Vs0 of the inter-terminal voltage v and the measured value Is of the charging current i immediately after the charging start time Ts are input to the internal resistance measurement block 40. The internal resistance measurement block 40 calculates the internal resistance Ri of the power storage device 31 (FIG. 1A) based on the input measured values ​​Vs, Vs0, and Is. Specifically, the internal resistance Ri is calculated using the following equation (1): It can be put out.

[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 are used to measure physical quantities that depend on the degree of deterioration of the power storage device 31. The voltage sensor 25 measures the voltage between the terminals of the power storage device 31 and also functions as a degradation sensor. The current sensor 26 measures the charging current of the power storage device 31 and also functions as a degradation sensor.

[0022] When charging starts at charging start time Ts, as time passes, 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 operating voltage Vt, and measures the elapsed time Tb from the charging start time Ts to the time Tt when the inter-terminal voltage v reaches the timer operating voltage Vt.

[0023] 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 formula (2).

[0024] Ta = A × Tb + C (2) A finish charging time calculation table 44 defines the relationship between the internal resistance Ri and the coefficients A and C. The timer operating 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. Once the values ​​of the coefficients A and C are determined, the timer operating 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 time Te, when the timer operation time Ta has elapsed since time Tt, when the inter-terminal voltage v reached the timer operation voltage Vt. This stops charging. When the charging current i stops flowing, the voltage drop due to the internal resistance Ri becomes 0 V, and the inter-terminal voltage v drops by the amount of the voltage drop caused by the internal resistance Ri. Generally, the internal resistance Ri increases rapidly after time Tt. Therefore, the drop in the inter-terminal voltage v at the charge completion time Te is greater than the increase in the inter-terminal voltage v at the charge start time Ts. At the end of charging, the open-circuit voltage of the storage device 31 (FIG. 1A) becomes approximately equal to the rated value Vf of the full charge voltage. The inter-terminal voltage v drops with a time constant specific to lead-acid batteries.

[0026] 1A to 2B will be described in comparison with a comparative example with reference to Fig. 3. Fig. 3 shows the change over time in the inter-terminal voltage v. The inter-terminal voltage v indicated by the thin dashed line in Fig. 3 is the same as the change over time in the inter-terminal voltage v shown in Fig. 2B.

[0027] In FIG. 3, the thick solid line indicates the change over time in the inter-terminal voltage v when the degradation of the power storage device 31 is advanced. As the degradation 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 charging start time Ts is the same, as the internal resistance Ri increases, the increase in the inter-terminal voltage v increases. Therefore, the increase in the inter-terminal voltage v at the charging start time Ts is greater than the increase in the inter-terminal voltage v when degradation is not advanced. Therefore, the measured value Vs1 of the inter-terminal voltage v immediately after the charging start time Ts is higher than the measured value Vs0 when degradation is not advanced. The inter-terminal voltage v increases over time.

[0028] Even during charging, the terminal voltage v is higher than the terminal voltage v indicated by the dashed line. At time Tt1, the terminal voltage v reaches the timer operating voltage Vt. The time Tb1 that has elapsed until the time Tt1 at which the voltage v reaches the timer operating voltage Vt is shorter than the time Tb that has elapsed when degradation is not advanced.

[0029] In the comparative example, the timer operation time calculation block 42 (FIG. 2A) calculates the timer operation time Ta using the same values ​​as the coefficients A and C used when the deterioration is not advanced. Because Tb1 is shorter than the elapsed time Tb, the calculated timer operation time Tac will be equal to or shorter than the value of the timer operation time Ta when degradation is not advanced. Charging stops at time Tec, when the timer operation time Tac has elapsed since time Tt1, when the timer operation voltage Vt was reached. Because the sum of elapsed time Tb1 and timer operation time Tac is shorter than the sum of elapsed time Tb and timer operation time Ta, charging ends before full charge is achieved. Thus, if the charging time is set based on the measurement results of the inter-terminal voltage v, which is affected by the internal resistance Ri, full charge may not be achieved.

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

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

[0032] Next, another embodiment will be described with reference to Figures 4 and 5. Below, differences from the embodiment shown in Figures 1A to 3 will be described, and a description of the same configuration will be omitted.

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

[0034] The timer operating voltage calculation block 45 calculates the timer operating voltage Vt based on the internal resistance Ri and an operating voltage calculation table 46. The operating voltage calculation table 46 defines in advance the relationship between the internal resistance Ri and the timer operating voltage Vt. The arrival time measurement block 41 measures the elapsed time Tb based on the timer operating voltage Vt calculated by the timer operating 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 in calculating the timer operation time Ta are fixed values.

[0036] The effects of the embodiment shown in Fig. 4 will be described in comparison with the comparative example with reference to Fig. 5. Fig. 5 shows the change over time in the inter-terminal voltage v. The inter-terminal voltage v indicated by the thin dashed line in Fig. 5 is the same as the change over time in the inter-terminal voltage v shown in Fig. 2B.

[0037] In FIG. 5, the terminal voltage v of the power storage device 31 (FIG. 1A) in a state where the deterioration has progressed is shown as a thick line. The operating voltage calculation table 46 is defined so that as degradation progresses and the internal resistance Ri increases, the timer operating voltage Vt calculated by the timer operating voltage calculation block 45 increases. When the degradation of the power storage device 31 progresses, the inter-terminal voltage v reaches the timer operating voltage Vt when degradation is not progressing at time Tt1, when the elapsed time Tb1 has elapsed since the start of charging. In the comparative example in which a fixed value is used as the timer operating voltage Vt, as shown in FIG. 3 As explained above, charging ends at time Tec before the battery is fully charged.

[0038] In this embodiment, a voltage Vt1, which is higher than the timer operating voltage Vt when degradation is not advanced, is used as the timer operating voltage. Therefore, the time Tb2 elapsed from the charging start time Ts to the time Tt2 when the inter-terminal voltage v reaches the timer operating voltage Vt1 is longer than the time Tb1 elapsed until the timer operating voltage Vt is reached. The timer operating time calculation block 42 (FIG. 4) calculates the timer operating time Ta2. At the time Te2 when the timer operating time Ta2 has elapsed since the time Tt2, charging ends.

[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. Therefore, 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 comparative example. As a result, charging to a state closer to full charge is possible compared to the comparative example. The operating voltage calculation table 46 defines the relationship between the internal resistance Ri and the timer operating voltage Vt so that a sufficient charging time can be ensured to fully charge the power storage device 31 even if the internal resistance Ri of the power storage device 31 increases.

[0040] Another embodiment will be described with reference to Fig. 6. In the embodiment shown in Figs. 1A to 3, the timer operating voltage Vt is fixed, and the coefficients A and C for calculating the timer operating time Ta are changed based on the internal resistance Ri. In the embodiment shown in Figs. 4 and 5, the timer operating voltage Vt is changed based on the internal resistance Ri, and the coefficients A and C for calculating the timer operating time Ta are fixed.

[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, a timer operation voltage calculation block 45 calculates the timer operation voltage Vt based on the internal resistance Ri and an operation voltage calculation table 46. Furthermore, a timer operation time calculation block 42 calculates the timer operation time Ta based on the internal resistance Ri and a finish-up charge time calculation table 44. The embodiment shown in Fig. 6 allows for greater flexibility in setting the charging conditions compared to the embodiments shown in Figs. 1A to 3 and 4 to 5.

[0042] Another embodiment will be described with reference to Fig. 7. Differences from the embodiment shown in Figs. 1A to 3 will be described below, and descriptions of the same configurations will be omitted. In the embodiment shown in Figs. 1A to 3, the internal resistance Ri was calculated based on measured values ​​of the inter-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 calculated during the charging period.

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

[0044] When the charging current i is set to 0, the voltage drop due to the internal resistance Ri of the power storage device 31 (FIG. 1A) no longer occurs, and the inter-terminal voltage v drops by the amount of the voltage drop that occurred 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 magnitude I1, I2, I3 of the charging current i and the fluctuation range V1, V2, V3 of the terminal voltage v at the time when the supply of the charging current i is resumed.

[0045] If the supply of charging current i is stopped multiple times, the internal In this case, the average value of the calculated internal resistances Ri is adopted as the current internal resistance Ri of the power storage device 31 (FIG. 1A). After the internal resistance Ri is calculated, charging is performed in the same manner as in any of the embodiments of FIGS. 1A to 3, the embodiments of FIGS. 2 to 5, and the embodiment of FIG. 6.

[0046] When the charging current i is set to 0, the terminal voltage v drops with a certain time constant. It is preferable to stop the supply of the charging current i for a time that is 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. This allows the magnitude of the voltage drop caused by the internal resistance Ri to be measured with high accuracy.

[0047] In the embodiment shown in FIGS. 1A to 3, the embodiment shown in FIGS. 4 and 5, and the embodiment shown in FIG. 6, the internal resistance Ri of the energy 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 energy storage device 31 was measured during the charging period. Alternatively, 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 charging end time Te (FIG. 2B) and the fluctuation range of the terminal voltage v at time Te. The calculated value of internal resistance Ri is used to determine the charging conditions for the next charging. Note that, as described above, the present invention has been described based on the embodiments, but the present invention is not limited to these. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible.

[0048] Important Examples: As basic constituent elements, the new and inventive technical concept of the forklift and the charging system for charging the forklift configured as described above will be described in detail below.

[0049] The applicant of the present application manufactures, sells, and supplies charging systems including lithium-ion batteries (power storage devices installed on forklifts) and charging devices to multiple manufacturers (e.g., Company T, Company N, Company M, Company K, Company A, Company D, etc.).

[0050] Each company's forklift truck is powered by electricity supplied from a power storage device. The power storage device and charging device can be connected by a connection cable. The power storage device is charged by current supplied from the charging device via the connection cable. Basically, the power storage device is installed in the forklift truck and electricity is stored in the power storage device from the charging device. However, when charging, the power storage device can also be removed from the forklift truck and charged separately.

[0051] Charging devices are available in multiple voltages, including 24V, 36V, 48V, 72V, 80V, and 115V, but 24V, 36V, and 48V can all be charged using the same small charging device. Similarly, 72V, 80V, and 115V can all be charged using the same large charging device. In other words, small charging devices are compatible with three voltages: 24V, 36V, and 48V, while large charging devices are compatible with three voltages: 72V, 80V, and 115V. Naturally, other voltages are also possible.

[0052] Let's call the product from company T forklift T, the product from company N forklift N, the product from company M forklift M, the product from company K forklift K, the product from company A forklift A, the product from company D forklift D, and the product from any company X forklift X (X is an arbitrary value).

[0053] The charging device (in the embodiment, the small charging device and the large charging device) is provided with an 8-bit DIP switch that can take on a value between 0 and 15. The manufacturer of the forklift is assigned to the value of this DIP switch. For example, DIP switch value 1 is assigned to Company T, value 2 is assigned to Company N, value 3 is assigned to Company M, value 4 is assigned to Company K, value 5 is assigned to Company A, value 6 is assigned to Company D, and so on. Note that if a 16-bit DIP switch is used, 256 different manufacturers can be distinguished. In particular, DIP switch value 0 means almighty, and setting the DIP switch value of the charging device to 0 will enable charging of forklifts from all manufacturers.

[0054] Similarly, a manufacturer identification code is stored in the memory of the power storage device, and the manufacturer identification code value for a power storage device made by company T is assigned as 1, value 2 for company N, value 3 for company M, value 4 for company K, value 5 for company A, value 6 for company D, etc. The manufacturer identification code is stored in a memory such as a ROM, but a dip switch may also be provided so that the code can be identified by its value.

[0055] Each company's charging device and power storage device are connected by a connection cable. In other words, the power storage device and charging device can be connected by the connection cable, and the power storage device is charged by the current supplied from the charging device via the connection cable. Naturally, Company T's charging device, power storage device, and connection cable have the Company T logo printed on them, making it possible to distinguish between the companies. Similarly, Company N's products have the Company N logo printed on them, and the same is true for other companies.

[0056] If the charging device of each company's identification information matches the identification information of the power storage device (identification information of the charging device and the forklift), it determines that charging is permitted and begins charging. On the other hand, if they do not match, charging does not occur. That is, the charging device controls whether or not to charge the charging device based on the identification information of the charging device and the forklift. Also, if it determines that charging is possible, it begins charging, but if it determines that charging is not possible, it does not begin charging. Note that these charging devices, the power storage device carried by the forklift, and the connection cable are common to all companies. For example, if a charging device from Company T is connected to a power storage device attached to a forklift from Company N using a connection cable from Company M, charging will not be possible because the identification information of the charging device and the forklift differ. However, if the dip switch value of Company T's charging device is set to 0, charging will occur without any problems. This reduces manufacturing costs and simplifies maintenance. Specifically, in the case of Company T, if there is an abnormality in the charging of Company T's charging device and Company T's forklift, a maintenance worker can bring an almighty charging device (dip switch value 0) and an almighty connection cable to the site and connect them to Company T's forklift, and depending on whether charging is possible or not, it can be determined whether Company T's charging device or Company T's forklift is faulty. [Explanation of symbols]

[0057] 10 Driver's seat 11. Fork 12 Front wheels 13 rear wheel 14 Controller 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 Vehicles 31 Energy storage device 32 DC plug 33 Relay 35 Electrical Load 40 Internal resistance measurement block 41 Arrival time measurement block 42 Timer operation time calculation block 43 Charging start / stop control block 44 Finishing charge time calculation table 45 Timer operating voltage calculation block 46 Operating voltage calculation table

Claims

[Claim 1] A forklift truck that is equipped with a power storage device and is driven by power supplied from the power storage device, the power storage device and a charging device that charges the power storage 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; the storage device stores storage device side identification information for identifying a manufacturer of the forklift, the charging device has a setting means for setting the identification information, and the charging device side identification information set by the setting means can be set to identification information that can take multiple values ​​for identifying the manufacturer of the forklift and an almighty value that allows charging of forklifts of all manufacturers, the charging device compares the charging device side identification information with the power storage device side identification information, and when the charging device side identification information matches the power storage device side identification information, permits charging of the power storage device, and when they do not match, performs control to prohibit charging of the power storage device, and further, when the charging device is in a specific setting state in which the almighty value is set as the charging device side identification information, performs control to permit charging of the power storage device regardless of the value of the power storage device side identification information; A forklift characterized by:

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