JP2013002990A - Leak detection device and battery forklift including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leak detection device having improved leak detecting accuracy and safety, and a battery forklift including the same.SOLUTION: A leak detection device 1 includes a leak detecting resistance R, detecting means 4, and determining means 5A. The leak detecting resistance R is provided between a terminal of a battery 2 mounted on a vehicle, and a detection point P of a vehicle body frame F. The detecting means 4 detects detection voltages V in both ends of the leak detecting resistance R. The determining means 5A determines the leak state of the battery 2 on the basis of the detection voltages V detected by the detecting means 4, and includes a comparator 6 and a reference voltage variable setting part 7. The comparator 6 is configured to compare the detection voltages V with a preset reference voltage Vr and to output a leak signal representing a leak state when the detection voltages become the reference voltage Vr or more. The reference voltage variable setting part 7 is configured to variably set the reference voltage Vr in the comparator 6.

Description

  The present invention relates to a leakage detection device and a battery forklift having the same.

  2. Description of the Related Art Conventionally, in a vehicle such as a battery forklift equipped with a high voltage battery, a leakage detection device that determines a leakage state of the battery is known (see, for example, Patent Document 1).

As shown in FIG. 8A, this leakage detection device 1 ′ includes a leakage detection resistor R, detection means 4, and determination means 5 ′.
The leakage detection resistor R is provided between a terminal (for example, a minus terminal) on one side of the battery 2 and the detection point P of the vehicle body frame F. The positive terminal and the negative terminal of the battery 2 are connected to a driving device 3 for driving and controlling, for example, a traveling motor and an engine.
The detection means 4 detects a potential difference (hereinafter referred to as “detection voltage”) V generated at both ends of the resistor R due to a leakage current flowing through the leakage detection resistor R at the time of leakage. However, V represents a magnitude | size (absolute value).
The determination unit 5 ′ determines the leakage state of the battery 2 based on the detection voltage V detected by the detection unit 4, and includes a comparison unit. As shown at times t1 to t2 in FIGS. 8B and 8C, the comparison unit compares the detection voltage V with a preset reference voltage Vr, and the detection voltage V is equal to or higher than the reference voltage Vr. For example, an H level leakage signal indicating the leakage state is output. Then, a warning notification means (not shown) connected to the determination means 5 ′ receives this leakage signal and notifies the outside that the battery 2 is in a leakage state.

Incidentally, in the leakage detection device 1 ′, the detection voltage V includes noise. This is caused by noise other than leakage (for example, noise generated from the driving device 3 or external noise) propagating to the vehicle body frame F. In this leakage detection device 1 ′, since the reference voltage Vr to be compared with the detection voltage V is set to a constant value, a large noise as shown at times t3 to t4 in FIGS. 8B and 8C. As a result, there is a problem that the leakage detection accuracy is poor, for example, it is easy to cause erroneous detection such as determining that there is a leakage current even though there is no leakage.
In addition, in such a leakage detection device 1 ′, even if the leakage can be detected, the actual traveling function of the vehicle is not affected at all. For example, the vehicle may travel in the leakage state. There was a problem with its safety.
Further, the leakage does not always occur continuously. Even if the leakage detection device 1 ′ detects the leakage at a certain time, the leakage may not be detected at another time. This can be said to be a potentially dangerous situation where leakage can occur in the future. However, since this leakage detection device 1 ′ is configured only to detect the presence or absence of leakage, there is a possibility that such a dangerous state may be missed. For this reason, there has been a demand for a leakage detecting device with better safety.

Japanese Utility Model Publication No. 6-2901

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the leakage detection apparatus which improved leakage detection accuracy and safety, and a battery forklift provided with the same.

In order to solve the above problems, the present invention provides (1) a leakage detection resistor provided between a terminal of a battery mounted on a vehicle and a detection point of a vehicle body frame, and detection of both ends of the leakage detection resistor. In the leakage detection device, comprising: a detection unit that detects a voltage; and a determination unit that determines a leakage state of the battery based on the detection voltage detected by the detection unit. A comparison unit that compares the detected voltage with a preset reference voltage, and outputs a leakage signal indicating a leakage state when the detected voltage is equal to or higher than the reference voltage; And a reference voltage variable setting unit capable of variably setting the reference voltage.
According to this configuration, the reference voltage in the comparison unit is variably set by the reference voltage variable setting unit. Therefore, since the influence of noise can be eliminated by appropriately changing the reference voltage, the leakage detection accuracy can be improved as compared with the prior art in which the reference voltage is set to a constant value.

In order to solve the above-mentioned problems, the present invention also includes (2) a leakage detection resistor provided between a terminal of a battery mounted on a vehicle and a detection point of the vehicle body frame, and both ends of the leakage detection resistor. In the leakage detecting device, comprising: a detecting unit that detects a detection voltage of the battery; and a determining unit that determines a leakage state of the battery based on the detection voltage detected by the detecting unit. An amplifying unit that amplifies the detection voltage detected by the means with a preset gain and a detection voltage amplified by the amplifying unit are compared with a preset reference voltage, and the detected voltage becomes equal to or higher than the reference voltage. An earth leakage test comprising: a comparison unit that outputs an earth leakage signal indicating that an earth leakage state is present; and a gain variable setting unit that can variably set the gain in the amplification unit It is obtained by the apparatus.
According to this configuration, the gain in the amplifying unit is variably set by the gain variable setting unit. Therefore, since the influence of noise can be eliminated by appropriately changing the gain, the leakage detection accuracy can be improved.

In the configuration (2), it is preferable that (3) the determination unit further includes a reference voltage variable setting unit that can variably set the reference voltage in the comparison unit.
According to this configuration, the gain in the amplifying unit is variably set by the gain variable setting unit, and the reference voltage in the comparison unit is variably set by the reference voltage variable setting unit. Therefore, leakage detection accuracy can be further improved by appropriately changing and combining the reference voltage and the gain.

In the above configurations (1) to (3), (4) the determination unit is further configured to output the leakage signal output from the comparison unit when the leakage signal exceeds a preset detection time. It is preferable to include a leakage signal determination unit that outputs the leakage signal as an effective leakage signal, and a detection time variable setting unit that can variably set the detection time in the leakage signal determination unit.
According to this configuration, when the leakage signal continues to be output beyond the detection time, the leakage signal determination unit is configured to output the leakage signal as valid. Therefore, erroneous detection due to noise that occurs instantaneously in a time shorter than the detection time can be prevented.
Further, according to this configuration, the detection time in the leakage signal determination unit is variably set by the detection time variable setting unit. Therefore, since the influence of noise can be eliminated by appropriately changing the detection time, the leakage detection accuracy can be increased.

In the above configurations (1) to (4), (5) when the leakage signal is output from the determination means, the leakage signal is input to visually notify that the battery is in a leakage state. It is preferable to further include at least one of a warning display unit that performs warning and a warning sound generation unit that performs auditory notification.
According to this configuration, when the warning display means and / or the warning sound generation means receive a more reliable leakage signal input from which the influence of noise has been sufficiently eliminated, the leakage state is notified. Yes. Accordingly, erroneous notification of the determination result of the leakage state is prevented, and more reliable notification is possible.

In the above configurations (1) to (5), (6) when the leakage signal is output from the determination means, the traveling function of the vehicle can be reduced or stopped by receiving the input of the leakage signal. It is preferable to further include a travel function control means for controlling the drive device of the vehicle.
According to this configuration, the drive function control unit is configured to control the drive device so that the travel function of the vehicle can be reduced or stopped when it is determined that the leakage state has occurred. Therefore, since the traveling function of the vehicle can be reduced or stopped at the time of electric leakage, the safety can be further improved as compared with the prior art.

In the above configurations (1) to (6), (7) when the leakage signal is output from the determination unit, the leakage information on the leakage state determined by the determination unit is received by receiving the leakage signal. It is preferable to further include an external monitor for displaying.
According to this configuration, the leakage information is displayed on the external monitor. Therefore, it is possible to know the situation at the time of occurrence of a leakage, and to easily investigate the cause of the leakage, which leads to an increase in safety.

In the above configurations (1) to (7), (8) connection state detection means for detecting the connection state of the battery to the vehicle body, and once the leakage signal is output from the determination means, the connection state detection means It is preferable to further include a leakage signal holding unit that holds the output of the leakage signal until receiving a release signal indicating that the connection state of the battery is released.
According to this configuration, once the leakage signal is output from the determination unit, the leakage signal is held until the leakage signal holding unit receives the release signal from the connection state detection unit. Therefore, since it is possible to know a potentially dangerous state in which leakage can occur in the future, which could not be achieved by the conventional technology, safety can be further improved.

In the above configurations (1) to (8), (9) a detection voltage provided between the detection means and the determination means, and a detection voltage detected by the detection means and a reference voltage are differentially input, and the difference value is obtained. It is preferable that the apparatus further includes a differential amplifier that amplifies and outputs to the determination unit, and the determination unit determines the leakage state of the battery based on the detection voltage output by the differential amplifier.
According to this configuration, the differential amplifier compares the detection voltage detected by the detection unit and the reference voltage, and the determination unit compares the detection voltage output by the differential amplifier and the reference voltage. It is configured as follows. Accordingly, since the leakage state is determined twice by the differential amplifier and the determination unit, the leakage state can be determined more accurately.

In particular, a battery forklift in a vehicle is equipped with a battery having a high voltage (for example, a voltage of 120 V DC or more) and includes a lot of noise included in the detection voltage V. Therefore, a leakage detection device with higher leakage detection accuracy and safety is required. Become.
Therefore, in order to realize this, it is preferable to mount the leakage detection device according to any one of the configurations (1) to (9) on the battery forklift.

  According to the present invention, it is possible to provide a leakage detection device with improved leakage detection accuracy and safety, and a battery forklift equipped with the leakage detection device.

(A) is a block diagram showing a schematic configuration of the leakage detection device according to the first embodiment of the present invention, (B) is a graph showing a temporal change of the detection voltage V, and (C) is a time of the leakage signal. It is a graph which shows a change. (A) is a block diagram showing a schematic configuration of a leakage detection device according to the second embodiment of the present invention, (B) is a graph showing a temporal change in detection voltage (V × G), and (C) is a leakage current. It is a graph which shows the time change of a signal. (A) is a block diagram showing a schematic configuration of a leakage detecting device according to a third embodiment of the present invention, (B) is a graph showing a temporal change in detected voltage (V × G), (C) and (D) ) Is a graph showing temporal changes in outputs of the comparison unit and the leakage signal determination unit when the detection time T is shortened, and (E) is a graph showing temporal changes in the detection voltage (V × G). , (F) and (G) are graphs showing temporal changes in outputs of the comparison unit and the leakage signal determination unit when the detection time T is increased. It is a block diagram which shows schematic structure of the leak detection apparatus by 4th Example of this invention. (A) is a block diagram showing a schematic configuration of a leakage detecting device according to a fifth embodiment of the present invention, (B) is a graph showing a temporal change in detected voltage (V × G), and (C) is a comparison. (D) is a graph showing the temporal change in the output of the leakage signal determination unit, (E) is a graph showing the temporal change in the output of the connection state detecting means, F) is a graph showing a temporal change in the output of the leakage signal holding means. (A) is a block diagram showing a schematic configuration of a leakage detecting device according to a sixth embodiment of the present invention, (B) is a graph showing a temporal change of the detection voltage V, and (B) is a detection voltage (V− Vr) is a graph showing the temporal change of Go, and (D) is a graph showing the temporal change of the leakage signal. It is a block diagram which shows schematic structure of the leak detection apparatus by 7th Example of this invention. (A) is a block diagram which shows schematic structure of the conventional leakage detection apparatus, (B) is a graph which shows the time change of the detection voltage V, (C) is a graph which shows the time change of a leakage signal. It is.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1A, the leakage detection device 1A of the first embodiment includes a leakage detection resistor R, detection means 4, and determination means 5A.
The leakage detection resistor R is provided between a terminal (for example, a minus terminal) on one side of the battery 2 and the detection point P of the vehicle body frame F. The positive terminal and the negative terminal of the battery 2 are connected to a driving device 3 for driving and controlling, for example, a traveling motor and an engine. The detection point P is preferably, for example, a conduction portion (a portion not coated with an insulating material) or an engagement portion (a portion fixed with a bolt or the like) of the vehicle body frame F. The battery 2 is connected to the vehicle body via a plug (not shown in FIG. 1).
The detecting means 4 detects a detection voltage V generated at both ends of the resistor R due to a leakage current flowing through the leakage detection resistor R at the time of leakage. Here, although the direction of the leakage current flowing through the leakage detection resistor R changes depending on the leakage state, the detection means 4 detects the magnitude (absolute value) of the detection voltage V for the sake of simplicity. .
The determination unit 5 </ b> A determines the leakage state of the battery 2 based on the detection voltage V detected by the detection unit 4. The determination unit 5 </ b> A includes a comparison unit 6 and a reference voltage variable setting unit 7.

The comparison unit 6 compares the detection voltage V with a preset reference voltage Vr, and outputs, for example, an H level leakage signal indicating a leakage state when the detection voltage V becomes equal to or higher than the reference voltage Vr. To do.
The reference voltage variable setting unit 7 includes a volume, a switch, or the like, and is configured to be able to variably set the reference voltage Vr in the comparison unit 6 continuously or discretely by adjusting these.

Next, the operation and effect of the leakage detection device 1A will be briefly described.
First, when there is no leakage, since the leakage current does not flow through the leakage detection resistor R, the detection voltage V detected by the detection means 4 becomes zero. For this reason, in the leakage detection apparatus 1 </ b> A, an L level leakage signal is output from the comparison unit 6.
When leakage occurs, as shown in FIGS. 1B and 1C, an H-level leakage signal is output from the comparison unit 6 at times t1 to t2 when the detection voltage V is equal to or higher than the reference voltage Vr. .

  Here, if the reference voltage Vr is set to a high value in advance, as is apparent from FIGS. 1B and 8B, the influence of noise is eliminated. Thus, the leakage detection accuracy can be increased by appropriately changing the reference voltage Vr. Since the influence of noise varies depending on the type of battery 2 and the usage environment, the reference voltage Vr is preferably set to an optimum value according to the type of battery 2 and the usage environment.

(Second embodiment)
As shown in FIG. 2A, the leakage detection device 1B of the second embodiment is different from the leakage detection device 1A of the first embodiment in that the determination unit 5B further includes an amplification unit 8 and a variable gain setting unit 9. Is different. Therefore, only this point will be described.

The amplifying unit 8 amplifies the detection voltage V detected by the detection means 4 with a preset gain G.
The gain variable setting unit 9 includes a volume, a switch, or the like, and is configured so that the gain G in the amplifying unit 8 can be variably set continuously or discretely by adjusting these. Here, it is assumed that the gain G is variably set in the range of 0 to 1.
The comparison unit 6 compares the detection voltage (V × G) amplified by the amplification unit 8 with a preset reference voltage Vr, and when the detection voltage (V × G) is equal to or higher than the reference voltage Vr, For example, an H level leakage signal indicating that the leakage state is present is output.

Next, the operation and effect of the leakage detection device 1B will be briefly described. It is assumed that the value of the gain G in the amplifying unit 8 is preset to 0.5.
First, when no leakage occurs, an L-level leakage signal is output from the comparison unit 6 as in the leakage detection device 1A.
When leakage occurs, as shown in FIGS. 2B and 2C, at time t1 to t2 when the detection voltage (V × G) is equal to or higher than the reference voltage Vr, the comparison unit 6 outputs an H level leakage signal. Is output.

Here, since the gain G is set to 0.5 (a value lower than 1), as apparent from FIGS. 1B and 8B, the influence of noise is eliminated. Thus, by appropriately changing the gain G, the leakage detection accuracy can be increased. Note that the gain G is also preferably set to an optimum value according to the type of battery 2 and the use environment, like the reference voltage Vr.
Furthermore, in addition to setting the gain G to be low, the influence of noise can be further eliminated by setting the reference voltage Vr to be high, and the leakage detection accuracy can be further increased.

(Third embodiment)
As shown in FIG. 3 (A), the leakage detection apparatus 1C of the third embodiment is that the determination means 5C further includes a leakage signal determination section 10 and a detection time variable setting section 11. It is different from the apparatus 1B. Therefore, only this point will be described.

The leakage signal determination unit 10 outputs the leakage signal as an effective leakage signal when the leakage signal output from the comparison unit 6 continues to be output even after the preset detection time T has been exceeded.
The detection time variable setting unit 11 includes a volume or a switch (for example, a rotary switch), and is configured such that the detection time T in the leakage signal determination unit 10 can be variably set continuously or discretely by adjusting these. Has been.

Next, the operation and effect of the leakage detection device 1C will be briefly described.
For example, as shown in FIGS. 3B to 3G, the detection voltage (V × G) output from the amplifying unit 8 is increased and the leakage signal is output from the comparing unit 6 at times t1 to t3. Think about the case. In this case, it is not clear whether this leakage signal is due to leakage or noise.
Here, if the detection time T (T = t2−t1) is set to be short in advance, the leakage signal determination unit 10 determines the detection time T as apparent from FIGS. 3B and 3C. It is determined that the leakage signal continues to be output from the comparison unit 6, and the leakage signal is output as valid (output as H level) at times t2 to t3. That is, it is determined that the change in the detected voltage at times t1 to t3 is due to electric leakage instead of noise.
On the other hand, if the detection time T (T = t4-t1) is set to be long in advance, the leakage signal determination unit 10 exceeds the detection time T, as is apparent from FIGS. 3 (F) and 3 (G). Therefore, it is determined that the leakage signal is not output from the comparison unit 6, and the leakage signal is invalidated (output as L level). That is, it is determined that the change in the detected voltage at times t1 to t3 is due to noise, not leakage.

  As described above, by appropriately changing the detection time T, it is possible to easily distinguish between leakage and noise, and thus leakage detection accuracy can be increased. In particular, by setting the detection time T to be long, erroneous detection due to noise that occurs instantaneously can be prevented.

(Fourth embodiment)
As shown in FIG. 4, the leakage detection device 1D of the fourth embodiment is further provided with a warning display means 12, a warning sound generation means 13, a traveling function control means 14, and an external monitor 15. This is different from the leakage detection device 1C of the third embodiment. Therefore, only this point will be described.

When the leakage signal (effective leakage signal) is output from the determination unit 5D, the warning display unit 12 receives the leakage signal and visually notifies that the battery 2 is in a leakage state. is there. The warning display means 12 consists of an LED display device, for example.
When the leakage signal is output from the determination unit 5D, the warning sound generation unit 13 receives the leakage signal and audibly notifies that the battery 2 is in a leakage state. The warning sound generating means 13 is composed of an alarm sound generating device, for example.
When the leakage signal is output from the determination unit 5D, the traveling function control unit 14 receives the leakage signal and receives a control signal from the driving device 3 of the vehicle so that the traveling function of the vehicle can be reduced or stopped. Send. The drive device 3 receives this control signal, for example, reduces the speed of the motor or prohibits starting of the engine of the vehicle that is stopped.
When the leakage signal is output from the determination unit 5D, the external monitor 15 receives the leakage signal and receives the leakage information on the leakage state determined by the determination unit 5D (for example, V, G, V × G, Vr, T, etc. and leakage occurrence time etc.) are displayed.

Next, the operation and effect of this leakage detection device 1D will be briefly described.
Since the warning display means 12 and / or the warning sound generation means 13 receives an input of a leakage signal in which the influence of noise is sufficiently eliminated, more reliable notification can be performed.
Moreover, since the traveling function control means 14 reduces or stops the traveling function of the vehicle at the time of electric leakage, the safety can be further improved as compared with the prior art.
Furthermore, since the external monitor 15 displays the leakage information, it is possible to know the situation at the time of occurrence of the leakage and to easily investigate the cause of the leakage. This results in increased safety.

(5th Example)
As shown in FIG. 5A, the leakage detection apparatus 1E of the fifth embodiment is further provided with a connection state detection means 17 and a leakage signal holding means 18 in that the leakage detection apparatus 1C of the third embodiment. Is different. Therefore, only this point will be described.

As shown in FIG. 5A, the battery 2 is connected to the vehicle body and the driving device 3 via a plug 16 when used.
The connection state detection means 17 detects the connection state of the battery 2 to the vehicle body. The connection state detection means 17 outputs a release signal when the connection state of the battery 2 is released.
The leakage signal holding means 18 is composed of, for example, a latch circuit. The leakage signal holding unit 18 holds the output of the leakage signal after the leakage signal (valid) is output from the determination unit 5E. This held leakage signal remains held (not reset) until a release signal is received from the connection state detection means 17.

Next, the operation and effect of the leakage detection device 1E will be briefly described.
First, as shown in FIGS. 5B to 5D, an effective leakage signal is output from the leakage signal determination unit 10 at the time of leakage at times t1 to t3 (see times t2 to t3 in FIG. 5). The leakage signal holding means 18 receives this leakage signal and holds the output of the leakage signal from the time t2. Then, as shown in FIG. 5 (E), when the connection of the battery 2 is released at time t4, the connection state detection means 17 that detects this outputs a release signal, and the leakage signal holding means 18 receives the release signal. To reset the leakage signal to L level.

  Accordingly, since the leakage signal is held unless the connection of the battery 2 is released, it can be known from this that the leakage has occurred before. That is, since it is possible to know a potentially dangerous state in which leakage can occur in the future, which could not be achieved by the conventional technology, safety can be further improved.

(Sixth embodiment)
As shown in FIG. 6 (A), the leakage detection apparatus 1F of the fifth embodiment is different from the leakage detection apparatus 1A of the first embodiment in that a differential amplifier 19 is further provided. Therefore, only this point will be described.

The differential amplifier 19 is provided between the detection unit 4 and the determination unit 5F. The differential amplifier 19 is configured to differentially input the detection voltage V detected by the detection means 4 and the reference voltage Vr, amplify the difference value with a predetermined gain Go, and output it to the determination means 5F. Yes.
The comparison unit 6 compares the detection voltage (V−Vr) × Go output by the differential amplifier 19 with the reference voltage Vr, and when the detection voltage (V−Vr) × Go becomes equal to or higher than the reference voltage Vr. For example, an H level leakage signal indicating that the leakage state is present is output. Here, the gain Go is set to Go = 1.

Next, the operation and effect of the leakage detection device 1F will be briefly described.
When a leakage occurs, as shown in FIGS. 6B and 6C, at time t1 to t2 when the detected voltage (V−Vr) × Go is equal to or higher than the reference voltage Vr, the comparator 6 outputs an H level leakage signal. Is output.

  As is apparent from a comparison between FIGS. 6B and 6C, the differential amplifier 19 compares the detection voltage V with the reference voltage Vr, thereby eliminating the influence of noise to some extent. Further, the comparison unit 6 of the determination means 5F compares the detection voltage (V−Vr) × Go output by the differential amplifier 19 with the reference voltage Vr, and thereby the influence of noise is almost eliminated. That is, since the leakage state is determined twice by the differential amplifier 19 and the determination unit 5F, the leakage state can be determined more accurately. Here, although the common reference voltage Vr is used in the differential amplifier 19 and the comparison unit 6, it goes without saying that different first reference voltage and second reference voltage may be used.

(Seventh embodiment)
As shown in FIG. 7, the leakage detecting device 1G of the seventh embodiment is configured such that the leakage detection resistor R, the detection means 4 and the comparison unit 6 are all N (here, N = 3), and The point provided with the leakage signal determination unit 10 is different from the leakage detection apparatus 1A of the first embodiment. Therefore, only this point will be described.

Each leakage detection resistor R is provided between one terminal (for example, a minus terminal) of the battery 2 and each detection point P1 to P3 of the vehicle body frame F. Each detection point P1-P3 is arrange | positioned at the front part of the vehicle body frame F, respectively, the intermediate part, and the rear part, for example.
Each of the three detection means 4 is connected to the corresponding leakage detection resistor R and detects the detection voltages V1 to V3. The detection voltages V <b> 1 to V <b> 3 are compared with the reference voltage Vr in each comparison unit 6, and a leakage signal is output from the comparison unit 6. The leakage signal determination unit 10 outputs the leakage signal determined to be leakage when two or more leakage signals among the leakage signals output from the comparison units 6 are at the H level.

  Therefore, the leakage signal determination unit 10 of the determination unit 5G is configured not to output a leakage signal unless leakage is detected at a detection point at a predetermined position or more among a plurality of detection points. The state can be determined. Here, in each comparison unit 6, the common reference voltage Vr by one reference voltage variable setting unit 7 is used. However, each comparison unit 6 includes a reference voltage variable setting unit 7 corresponding to each reference voltage variable setting unit 7. Needless to say, different first to third reference voltages may be used according to 7.

  As mentioned above, although preferable embodiment of this invention was described, the structure of this invention is not limited to these embodiment.

In the first to seventh embodiments described above, the leakage detection resistor R is provided between the negative terminal of the battery 2 and the detection point P (P1 to P3) of the vehicle body frame F, but is not limited thereto. For example, the leakage detection resistor R may be provided between the positive terminal of the battery 2 and the detection points P (P1 to P3) of the vehicle body frame F.
In the determination means 5A to 5G, the processing may be executed by the CPU or the like until the leakage signal is output based on the detection voltage V.
The reference voltage Vr in the comparison unit 6 and the differential amplifier 19, the gains G and Go in the amplification unit 8 and the differential amplifier 19, and the detection time T in the leakage signal determination unit 10 are set to various values. Needless to say.

  By the way, battery forklifts, in particular, are equipped with a battery with a high voltage (for example, a voltage of 120 V DC or more), and there is a lot of noise included in the detection voltage. become. Therefore, in order to realize this, it is very useful to mount the above leakage detection device on a battery forklift.

1A to 1G, 1 'Leakage detection device 2 Battery 3 Drive device 4 Detection means 5A to 5G, 5' Determination means 6 Comparison unit 7 Reference voltage variable setting unit 8 Amplification unit 9 Variable gain setting unit 10 Leakage signal determination unit 11 Detection time Variable setting section 12 Warning display means 13 Warning sound generation means 14 Travel function control means 15 External monitor 16 Plug 17 Connection state detection means 18 Leakage signal holding means 19 Differential amplifier F Body frame G, Go gains P, P1 to P3 Detection points R, R1 to R3 Leakage detection resistance T Detection time V, V1 to V3 Detection voltage Vr Reference voltage

Claims (10)

A leakage detection resistor provided between a battery terminal mounted on the vehicle and a detection point of the vehicle body frame;
Detecting means for detecting a detection voltage at both ends of the leakage detection resistor;
In the leakage detection device comprising: a determination unit that determines a leakage state of the battery based on the detection voltage detected by the detection unit;
The determination means includes
A comparison unit that compares the detection voltage with a preset reference voltage and outputs a leakage signal indicating a leakage state when the detection voltage is equal to or higher than the reference voltage;
And a reference voltage variable setting unit capable of variably setting the reference voltage in the comparison unit. A leakage detection resistor provided between a battery terminal mounted on the vehicle and a detection point of the vehicle body frame;
Detecting means for detecting a detection voltage at both ends of the leakage detection resistor;
In the leakage detection device comprising: a determination unit that determines a leakage state of the battery based on the detection voltage detected by the detection unit;
The determination means includes
An amplifying unit for amplifying the detection voltage with a preset gain;
A comparison unit that compares the detection voltage amplified by the amplification unit with a preset reference voltage, and outputs a leakage signal indicating a leakage state when the detection voltage becomes equal to or higher than the reference voltage;
And a gain variable setting unit capable of variably setting the gain in the amplification unit. The determination means further includes:
The leakage detecting device according to claim 2, further comprising a reference voltage variable setting unit that can variably set the reference voltage in the comparison unit. The determination means further includes:
When the leakage signal output from the comparison unit continues to be output even after exceeding a preset detection time, the leakage signal determination unit outputs the leakage signal as an effective leakage signal;
The leakage detection device according to claim 1, further comprising: a detection time variable setting unit capable of variably setting the detection time in the leakage signal determination unit.   When the leakage signal is output from the determination means, a warning display means for visually informing that the battery is in a leakage state upon receiving the leakage signal and a warning sound generation means for audibly notification The leakage detecting device according to claim 1, further comprising at least one of the above.   When the leakage signal is output from the determination unit, a traveling function control unit that receives the leakage signal and controls the driving device of the vehicle so that the traveling function of the vehicle can be reduced or stopped. The leakage detecting device according to claim 1, further comprising:   When the leakage signal is output from the determination unit, the device further includes an external monitor that receives the input of the leakage signal and displays leakage information regarding the leakage state determined by the determination unit. The leakage detection device according to any one of claims 1 to 6. Connection state detection means for detecting a connection state of the battery to the vehicle body;
Once the leakage signal is output from the determination means, the leakage current that keeps the output of the leakage signal held until receiving a release signal indicating that the connection state of the battery is released from the connection state detection means. The leakage detecting device according to claim 1, further comprising a signal holding unit. A differential amplifier provided between the detection means and the determination means, wherein a detection voltage detected by the detection means and a reference voltage are differentially input, a differential value thereof is amplified and output to the determination means; In addition,
The leakage detection device according to claim 1, wherein the determination unit determines a leakage state of the battery based on a detection voltage output by the differential amplifier.   A battery forklift comprising the leakage detecting device according to any one of claims 1 to 9.

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