JP6772720B2 - Leakage detector - Google Patents

Description

The present invention relates to an earth leakage detection device for a vehicle provided with a battery power source for driving a motor.

Vehicles equipped with a motor as a power source For example, an electric vehicle or a hybrid vehicle is equipped with a battery power source (also referred to as a battery pack) for driving the motor, and supplies the output of the battery power source to the motor drive unit. The battery unit including the battery power supply and its peripheral portion is a so-called high-voltage circuit, and this high-voltage circuit is insulated from the ground of the vehicle body to prevent electric shock.

For high-voltage circuits, sufficient measures are required against electric leakage (also called insulation failure) caused by the ingress of water or dust.

As a countermeasure, an earth leakage detection device for detecting an earth leakage of a high voltage circuit is installed in the vehicle. This earth leakage detection device detects the resistance value of the insulation resistance between the high voltage circuit and the ground of the vehicle body, and when the resistance value of the insulation resistance drops below a predetermined set value, the high voltage circuit It is determined that there is an electric leakage in.

Japanese Patent No. 5382813 Japanese Unexamined Patent Publication No. 2014-202696

The earth leakage detection device only detects the presence or absence of an electric leakage, and cannot detect where the electric leakage site is. Leakage sites are manually detected by workers at dealers and service factories where vehicles are brought in. This work takes a lot of time and effort.

An object of the present invention is to provide an electric leakage detection device capable of detecting the presence or absence of an electric leakage in a battery unit including a battery power supply and its peripheral portion, and if there is an electric leakage, it can accurately and quickly detect the location of the electric leakage part. It is to be.

The earth leakage detecting device of the invention according to claim 1 of the present application is an earth leakage detecting device of a vehicle provided with a battery power source composed of a plurality of battery cells connected in series, and is an insulation resistance detecting means, an earth leakage determining means, and a battery. It is provided with a voltage measuring means, a potential difference measuring means, and an electric leakage site discriminating means. The insulation resistance detecting means detects the resistance value of the insulation resistance between the battery unit including the battery power supply and its peripheral portion and the ground of the vehicle. The electric leakage determining means determines the presence or absence of electric leakage in the battery unit according to the detection result of the insulating resistance detecting means. The battery voltage measuring means measures the battery voltage, which is the total value of the plurality of battery cells. The potential difference measuring means measures the potential difference between the battery unit and the ground when the determination result of the leakage determining means is that there is an electric leakage. The earth leakage site determination means determines an earth leakage site based on the measurement result of the battery voltage measuring means when the potential difference measuring means measures the potential difference and the potential difference measured by the potential difference measuring means. Further, the potential difference measuring means includes a voltmeter for measuring the potential difference between the battery unit and the ground, and the leakage site determining means includes a detection result of the insulating resistance detecting means and the voltage. The measurement result of the potential difference measuring means is corrected by the calculation based on the resistance value of the internal resistance of the meter, and the leakage portion is any of the battery cells in the battery power supply according to the measured result of the corrected potential difference measuring means. To determine.

The earth leakage detection device of the invention according to claim 2 of the present application is limited to the earth voltage measuring means and the earth leakage part determination means of the invention according to claim 1. The battery voltage measuring means measures individual cell voltages of the plurality of battery cells and calculates an average value of the plurality of cell voltages. The earth leakage part determination means determines which of the battery cells in the battery power source the earth leakage part is by dividing the measurement result of the potential difference measuring means by the average value of the plurality of cell voltages. ..

The earth leakage detection device of the invention according to claim 3 of the present application is limited to the earth leakage part determination means of the invention according to claim 1. The leakage site determining means divides the measurement result of the potential difference measuring means by the measurement result of the battery voltage measuring means when the potential difference measuring means measures the potential difference, thereby dividing the measurement result of the potential difference measuring means with respect to the battery voltage, thereby causing the battery unit and the ground. By calculating the ratio of the potential difference between the two and the above ratio and integrating the total number of cells constituting the battery power supply into the ratio, it is determined which of the battery cells in the battery power supply the leakage portion is. ..

The earth leakage detection device of the invention according to claim 4 of the present application is limited to the potentiometric titration measuring means of the invention according to any one of claims 1 to 3 . The potential difference measuring means is configured by connecting the voltmeter between either one of the positive power supply line and the negative power supply line derived from the battery power supply and the ground via a switch. The switch is turned off when the determination result of the leakage determination means is no leakage and turned on when there is leakage, and when the switch is turned on, either one of the positive power supply line and the negative power supply line and the ground are connected. The potential difference between the two is measured by the voltmeter as a discriminating factor for the leakage portion.

The earth leakage detection device of the invention according to claim 5 of the present application is limited to the potentiometric titration measuring means of the invention according to any one of claims 1 or 4 . The potentiometric titration measuring means measures the potentiometric titration when the determination result of the electric leakage determining means is an electric leakage and the vehicle stops traveling.

According to the electric leakage detection device of the present invention, it is possible to detect the presence or absence of electric leakage in the battery part including the battery power supply and its peripheral part, and if there is an electric leakage, it is possible to accurately and quickly detect where the electric leakage part is.

The block diagram which shows the structure of 1st and 2nd Embodiment of this invention. The flowchart which shows the control of 1st Embodiment of this invention. The flowchart which shows the control of the 2nd Embodiment of this invention.

[1] First Embodiment
The first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a main part of a vehicle equipped with a battery power source for driving a motor, for example, an electric vehicle or a hybrid vehicle.
The battery power supply (also referred to as a battery pack) 1 is derived from a plurality of assembled batteries (also referred to as battery modules) 2a to 2n connected in series with each other, and from the positive side terminal and the negative side terminal of the series circuit of these assembled batteries 2a to 2n, respectively. The positive side power supply line P and the negative side power supply line N, and the positive side contact (relay contact) 5 and the negative side contact (relay contact) 6 inserted and connected to the positive side power supply line P and the negative side power supply line N, respectively. The perimeter is covered with an insulating case.

The assembled batteries 2a to 2n are formed by connecting a plurality of battery cells 3a to 3n in series to each other, and each includes a voltage measuring unit (battery voltage measuring means) 4. The voltage measuring unit 4 measures and measures the individual voltage (called cell voltage) Vcell of the battery cells 3a to 3n and the assembled battery voltage (also referred to as battery voltage) Vm which is the total value of each cell voltage Vcell. The average value of the cell voltage Vcell is calculated. The total value of the assembled battery voltage Vm measured by each voltage measuring unit 4 corresponds to the voltage Vb of the battery power supply 1.

The number of battery power sources 1 is appropriately selected according to the traveling performance and size of the vehicle. Further, a fuse for overcurrent protection, a service plug for connecting maintenance equipment, and the like are arranged between the assembled batteries 2a to 2n in the battery power supply 1.

The motor drive unit 10 which is a high voltage device is connected to the positive power supply line P and the negative power supply line N derived from the battery power supply 1. The motor drive unit 10 includes an inverter that converts the voltage Vb of the battery power supply 1 into an AC voltage having a frequency according to a command from the vehicle control unit 60, which will be described later, and the AC voltage converted by the inverter is used as driving power for the motor 11. Output as. This output causes the motor 11 to operate, and its power is transmitted to the drive shaft of the vehicle.

Further, a DC / DC converter 12 which is a high voltage device and a charger 13 which is also a high voltage device are connected to the positive power supply line P and the negative power supply line N derived from the battery power supply 1. The DC / DC converter 12 converts the voltage Vb of the battery power supply 1 into a DC voltage at a level necessary for the operation of various electric devices of the vehicle and outputs the DC / DC converter 12. The charger 13 includes a generator that generates electricity in response to the rotation of the drive shaft of the vehicle, converts the output voltage (AC voltage) of the generator into a DC voltage of a predetermined level, and charges the battery power supply 1 as regenerative energy. To do. Further, when the vehicle control unit 60, which will be described later, executes control for an electric leakage state, the charger 13 stops the charging operation in response to a command from the vehicle control unit 60.

A so-called high voltage circuit is formed by a battery unit including a positive power supply line P and a negative power supply line N of the battery power supply 1 and its peripheral portion, a motor drive unit 10, a DC / DC converter 12, a charger 13, and the like. .. This high-voltage circuit is insulated from the ground G by being held away from the ground (chassis) G of the vehicle body or by being held via an insulator in order to prevent electric shock. Due to this insulation, an insulating resistor exists between the high voltage circuit and the ground G, and the resistance value R of the insulating resistor is usually an infinite value.

For high-voltage circuits, in addition to such insulation measures, it is necessary to give due consideration to the possibility of electric leakage (also called insulation failure) caused by the ingress of water or dust. If an electric leakage occurs in the high-voltage circuit, the resistance value R of the insulation resistance between the high-voltage circuit and the ground G decreases. For example, when an electric leakage occurs in the negative power supply line N, the resistance value R of the insulation resistance 100 between the negative power supply line N and the ground G decreases as shown by the broken line in FIG.

On the other hand, a battery management unit, so-called BMU (Battery Management Unit) 20, is arranged in the vicinity of the battery power supply 1. The BMU 20 includes a main control unit 21, an insulation resistance detection unit (insulation resistance detection means) 30, a potential difference measurement unit (potentiometric titration measurement means) 40, an earth leakage determination unit 50, and a memory 51.

The main control unit 21 controls the opening and closing of the positive contact 5 and the negative contact 6 in the battery power supply 1 in response to a command from the vehicle control unit 60 that controls the running of the vehicle, and controls the opening and closing of the positive contact 5 and the negative contact 6 in the assembled batteries 2a to 2n, respectively. Each cell voltage Vcell and each assembled battery voltage Vm measured by the voltage measuring unit 4 are monitored, and the temperatures of the assembled batteries 2a to 2n are monitored by a temperature sensor. If these monitoring results are abnormal, the battery power supply 1 is used. The protection control for forcibly opening the positive contact 5 and the negative contact 6 regardless of the command from the vehicle control unit 60 is executed. Further, the main control unit 21 notifies the vehicle control unit 60 of the determination result of the leakage determination unit 50.

The insulation resistance detection unit 30 includes an AC power supply 31 that outputs an AC voltage Vc at a fixed cycle, a resistor 32 that is wired and connected between one end of the AC power supply 31 and the negative power supply line N, and an insulating coupling capacitor 33. , A voltage detection unit 34 that detects the voltage V1 generated between the interconnection point of the resistor 32 and the insulating coupling capacitor 33 and the ground G, and a high voltage circuit based on the detection voltage V1 of this voltage detection unit. A calculation unit 35 for calculating the resistance value R of the insulation resistance between the ground G and the ground G is included. The other end of the AC power supply 31 is connected to ground G. The calculation unit 35 notifies the leakage determination unit 50 of the calculated resistance value R as the detection result of the insulation resistance detection unit 30.

The voltage V1 detected by the voltage detection unit 34 is represented by the following equation using the AC voltage Vc, the resistance value Ra of the resistor 32, and the resistance value R of the insulation resistance.
V1 = Vc × R / (Ra + R)
When there is no electric leakage in the high-voltage circuit, the resistance value R of the insulation resistance between the high-voltage circuit and the ground G is in an infinite state and is much larger than the resistance value Ra of the resistor 32. At this time, the voltage V1 detected by the voltage detection unit 34 becomes the same value as the voltage Vc of the AC power supply 31 (V1 = Vc).

When water, dust, or the like infiltrates the high-voltage circuit and an electric leakage occurs in the high-voltage circuit due to the infiltration, the resistance value R of the insulation resistance between the leakage portion and the ground G decreases. At this time, the voltage V1 detected by the voltage detection unit 34 becomes a value lower than the voltage Vc of the AC power supply 31 by the amount of the voltage drop due to the resistor 32 (V1 <Vc).

The calculation unit 35 holds the voltage Vc of the AC power supply 31 and the resistance value Ra of the resistor 32 as known data in the internal memory, and these known data (Vc, Ra) and the detection voltage V1 of the voltage detection unit 34. Is calculated by back-calculating the resistance value R of the insulation resistance between the leakage site and the ground G by applying the above equation.

The potential difference measuring unit 40 includes a switch (relay contact) 41 having one end connected to the negative power supply line N by wiring, and a voltmeter 42 connected between the other end of the switch 41 and the ground G, and the switch 41. When is turned on, the difference V2 between the potential of the negative power supply line N, which is the battery unit, and the potential of the ground G is measured by the voltmeter 42 as a discriminating element for discriminating the leakage portion. The switch 41 operates in response to a command from the leakage determination unit 50, which will be described later, and is turned off when the determination result of the leakage determination unit 50 is no leakage, and the determination result of the leakage determination unit 50 is leakage and the above. Turns on when the vehicle stops running.

The earth leakage determination unit 50 includes the following earth leakage determination means, an earth leakage site determination means, and a storage means.
The electric leakage determining means determines the presence or absence of electric leakage in the high voltage circuit (battery unit) according to the resistance value R detected by the insulating resistance detecting unit 30. Specifically, the leakage determination means compares the resistance value R with the predetermined set value Rx, and if the resistance value R is equal to or greater than the set value Rx, determines that there is no leakage in the high voltage circuit, and the resistance value R is If it is less than the set value Rx, it is determined that there is an electric leakage in the high voltage circuit, and these determination results are notified to the main control unit 21.

The earth leakage part determination means discriminates an earth leakage part based on the measurement result of each voltage measurement unit 4 when the potential difference measurement unit 40 measures the potential difference V2 and the potential difference V2 measured by the potential difference measurement unit 40. Specifically, the leakage site determining means obtains the average value Vcell'of all the cell voltages Vcell in the battery power supply 1 from the average value calculated by each voltage measuring unit 4 in the battery power supply 1, and this average value. The potential difference V2 measured by the potential difference measuring unit 40 is divided by Vcell', and the division result (= V2 / Vcell') is used as an element for determining which of the battery cells in the assembled batteries 3a to 3n is the leakage site. To do.

The storage means uses the potential difference V2 measured by the potential difference measuring unit 40 as a discriminating element as to whether the leakage portion is the positive power supply line P, the negative power supply line N, or the assembled batteries 2a to 2n. It is stored in the memory 51. Further, the storage means obtains the division result (= V2 / Vcell') of the leakage portion determination means among all the battery cells 3a to 3n, 3a to 3n, ... The leakage portion is in the assembled batteries 2a to 2n. It is stored in the memory 51 as a discriminating element as to whether it is the third battery cell. The memory 51 retains the stored contents regardless of the operation stop due to the ignition switch 61 being turned off, which will be described later.

The vehicle control unit 60 includes an ignition switch 61 for instructing the driver to start and stop driving the vehicle, an accelerator opening sensor 62 for detecting the amount of operation of the accelerator operation by the driver as the accelerator opening, and a vehicle running. A vehicle speed sensor 63 for detecting the speed and a warning lamp (light emitting diode) 64 for notifying an abnormality such as leakage of a high voltage circuit are connected.

The vehicle control unit 60 includes the following first control means and second control means as main functions.
The first control means opens and closes the positive contact 5 and the negative contact 6 in the battery power supply 1 according to the operation of the ignition switch 61, the detection opening of the accelerator opening sensor 62, the detected vehicle speed of the vehicle speed sensor 63, and the like. It controls via the main control unit 21 of the above, and also controls the output of the motor drive unit 10 and the operation of the charger 13.

When the main control unit 21 notifies that there is an electric leakage, the second control means notifies that there is an electric leakage by turning on the warning lamp 64, and as a control for the electric leakage state, for example, the traveling ability of the vehicle. To limit. The limitation of the traveling ability is a control that limits the output of the motor drive unit 10 to keep the traveling speed of the vehicle below a certain level. Due to the lighting of the warning lamp 64 and the limitation of the driving ability, the driver of the vehicle can visually and drivingly detect that some abnormality has occurred in the driving vehicle.

The leakage detection device of the present embodiment is configured by the insulation resistance detection unit 30, the potential difference measurement unit 40, the leakage determination unit 50, the main control unit 21, the second control means of the vehicle control unit 60, and the like.

Next, the control executed by the leakage determination unit 50 will be described with reference to the flowchart of FIG.
The leakage determination unit 50 compares the resistance value R detected by the insulation resistance detection unit 30 with the set value Rx (step S1). When the resistance value R is equal to or greater than the set value Rx (NO in step S1), the leakage determination unit 50 determines that there is no leakage (step S2), and returns to the first step S1.

When the resistance value R is less than the set value Rx (YES in step S1), the electric leakage determination unit 50 determines that there is an electric leakage (step S3). Along with this determination, the earth leakage determination unit 50 lights (turns on) the warning lamp 64 (step S4), and controls the running ability of the vehicle via the main control unit 21 and the vehicle control unit 60 as control for the earth leakage state. It limits and prohibits charging of the charger 13 (step S5). Then, the electric leakage determination unit 50 monitors the running stop (stop) of the vehicle via the vehicle control unit 60 (step S6).

The driver of the vehicle visually detects the occurrence of an abnormality by turning on the warning lamp 64, and also senses that an abnormality has occurred in the vehicle due to the limitation of the driving ability. To do. With this detection, the driver moves the vehicle to a nearby safe place such as a shoulder or a parking lot and stops (stops).

When the vehicle stops (YES in step S6), the earth leakage determination unit 50 turns on the switch 41 of the potentiometric titration unit 40 (step S7). The potential difference measuring unit 40 operates by turning on the switch 41, and measures the difference V2 between the potential of the negative power supply line N and the potential of the earth G.

Subsequently, the leakage determination unit 50 obtains the average value Vcell'of all the cell voltage Vcells from the average value calculated by each voltage measuring unit 4 in the battery power supply 1, and the potential difference V2 measured by the potential difference measuring unit 40. Is divided by the above-obtained average value Vcell'(step S8).

Then, the leakage determination unit 50 determines whether the leakage portion (the portion where the resistance value R is lowered) is the positive power supply line P or the negative power supply line N for the potential difference V2 measured by the potential difference measurement unit 40. The memory 51 is stored as a discriminating factor as to whether or not the assembled batteries are 2a to 2n, and the above division result (= V2 / Vcell') is stored in all the battery cells 3a to 3n, 3a whose leakage sites are in the assembled batteries 2a to 2n. The battery cell is stored in the memory 51 as a discriminating factor as to which battery cell is of ~ 3n, ... (Step S9).

If the leakage site is the positive power supply line P, the difference (= Vb) between the potential of the positive power supply line P and the potential of the negative power supply line N is the voltmeter 42 of the potential difference measuring unit 40 via the insulation resistor. Join in. In this case, the potential difference V2 measured by the potential difference measuring unit 40 has the same value as the voltage Vb of the battery power supply 1 (V2 = Vb).

When the leakage site is the negative power supply line N, the difference (= zero) between the potential of the negative power supply line N and the potential of the same negative power supply line N is the potential difference measuring unit 40 via the insulation resistance (insulation resistance 100). Joins the voltmeter 42 of. In this case, the potential difference V2 measured by the potential difference measuring unit 40 naturally becomes zero (V2 = zero).

When the leakage site is any one of the battery cells in the assembled batteries 2a to 2n, the difference between the potential at the position of the battery cell and the potential of the negative power supply line N is the voltage of the potential difference measuring unit 40 via the insulation resistance. Join a total of 42. In this case, the potential difference V2 measured by the potential difference measuring unit 40 is lower than the voltage Vb of the battery power supply 1 and higher than zero (Vb> V2> zero). Specifically, if the leakage site is one battery cell in the middle position of all the battery cells 3a to 3n, 3a to 3n, ... In the assembled batteries 2a to 2n, the position of the battery cell in the middle position is The difference between the potential and the potential of the negative power supply line N is applied to the voltmeter 42 of the potential difference measuring unit 40 via the insulation resistor. In this case, the potential difference V2 measured by the potential difference measuring unit 40 is half the value of the voltage Vb of the battery power supply 1 (V2 = Vb / 2).

Following the storage process in step 9, the earth leakage determination unit 50 turns off the switch 41 of the potential difference measurement unit 40 (step S10). When the switch 41 is turned off, the operation of the potentiometric titration unit 40 is stopped. This is the end of the determination process.

The potentiometric titration unit 40 and the earth leakage determination unit 50 start operation and processing immediately when the vehicle stops running, and even if the time until the ignition switch 61 is turned off by the driver is short, within that time. Has sufficient ability to complete operation and processing.

After that, when the vehicle is brought to a store, a service factory, or the like, the worker connects a terminal such as a personal computer to the main control unit 21 or the vehicle control unit 60 of the BMU 20, and determines that it is stored in the memory 51. The element (potential difference V2 and division result (= V2 / Vcell')) is read into the terminal. The discriminant element read into the terminal is displayed on the display of the terminal.

The worker determines whether the leakage portion is the positive power supply line P, the negative power supply line N, or the assembled batteries 2a to 2n based on the magnitude of the potential difference V2 displayed on the display of the terminal. .. Further, depending on the size of the division result (= V2 / Vcell') displayed on the display of the terminal, the leakage site is among all the battery cells 3a to 3n, 3a to 3n, ... In the assembled batteries 2a to 2n. Determine which battery cell it is. The number of the battery cell where the leakage portion is located is the position counted from the negative power supply line N.

Therefore, the worker can recognize the presence or absence of an electric leakage in the high-voltage circuit without requiring labor and time-consuming work, and if there is an electric leakage, accurately and quickly recognize the location of the electric leakage site. Can be done.

[2] Second Embodiment
Depending on the voltage division ratio between the resistance value R of the insulation resistance and the resistance value r of the internal resistance of the voltmeter 42, the effect of the voltage drop at the resistance value R may not be negligible.

For example, when the leakage portion is the positive power supply line P, the difference (= Vb) between the potential of the positive power supply line P and the potential of the negative power supply line N is the potential difference measuring unit 40 via the insulation resistance of the leakage portion. It is in a state of being added to the voltmeter 42. At this time, if the resistance value R of the insulation resistance is not negligible with respect to the resistance value r of the internal resistance of the voltmeter 42, the potential difference V2 measured by the potential difference measuring unit 40 is the resistance value as shown in the following equation. The voltage drop at R deviates from the originally desired value. That is, the potential difference V2 does not become the same value as the voltage Vb of the battery power supply 1.
V2 = Vb × r / (R + r) ≠ Vb
When the leakage portion is the positive power supply line P, the difference (= Vb) between the potential of the positive power supply line P and the potential of the negative power supply line N passes through the insulation resistance (insulation resistance 100) of the leakage portion. It participates in the voltmeter 42 of the potential difference measuring unit 40. At this time, if the resistance value R of the insulation resistance is a size that cannot be ignored with respect to the resistance value r of the internal resistance of the voltmeter 42, the measured potential difference V2 deviates from the originally desired value by the voltage drop at the resistance value R. To do. That is, the potential difference V2 does not become Vb (V2 ≠ Vb).

If the leakage site is one of all the battery cells 3a to 3n, 3a to 3n, ... In the assembled batteries 2a to 2n, the potential of the battery cell position and the negative power supply line. The difference from the potential of N is applied to the voltmeter 42 of the potential difference measuring unit 40 via the insulation resistance of the leakage portion. At this time, if the resistance value R of the insulation resistance is not negligible with respect to the resistance value r of the internal resistance of the voltmeter 42, the potential difference V2 measured by the potential difference measuring unit 40 is the voltage drop at the resistance value R. Only deviates from the value you originally wanted to know. That is, the potential difference V2 is not half the value of the voltage Vb of the battery power supply 1 (V2 ≠ Vb / 2).

The internal resistance of the battery cells 3a to 3n and the wiring resistance of the positive power supply line P, the negative power supply line N, and the like are negligible because they are resistance values on the order of mΩ.

When the leakage portion is the negative power supply line N, the potential difference V2 is always zero regardless of the magnitude of the resistance value R, so that the determination of the leakage portion is not affected. However, when the leakage site is the positive power supply line P or any one battery cell in the assembled batteries 2a to 2n (when V2 ≠ zero), the deviation of the voltage drop at the resistance value R is the potential difference V2. If it is included in, it may not be possible to accurately determine which battery cell the leakage site is.

Therefore, in the second embodiment of the present invention, attention is paid to the point that the resistance value R of the insulation resistance is detected by the insulation resistance detection unit 30 and the point that the resistance value r of the internal resistance of the voltmeter 25 can be grasped in advance. , The leakage determination unit 50 measures the potential difference V2 measured by the potential difference measuring unit 40, the resistance value R detected by the insulating resistance detecting unit 30, and the resistance value r stored in advance by the potential difference measuring unit 40. By correcting the generated potential difference V2, the actual potential difference V2x between the leakage portion and the earth G is calculated, and the calculated potential difference V2x is stored in the memory 51 as a discriminating element of the leakage portion, and the calculated potential difference V2x is stored. Divide by the average value Vcell'of the cell voltage Vcell, and store the division result (= V2x / Vcell') in the memory 51 as a discriminating factor as to which battery cell the leakage site is.
That is, the earth leakage part determination means of the earth leakage determination unit 50 calculates the average value Vcell'of all the cell voltage Vcells measured by each voltage measurement unit 4 in the battery power supply 1, and is measured by the potential difference measurement unit 40. The actual potential difference V2x between the leakage site and the earth G is calculated by the calculation based on the potential difference V2, the resistance value R detected by the insulation resistance detection unit 30, and the resistance value r stored in advance, and this potential difference V2x is calculated. By dividing by the average value Vcell'calculated above, a discriminating factor as to which of the battery cells in the assembled batteries 2a to 2n is the leakage site is obtained.
The storage means of the earth leakage determination unit 50 determines whether the electric leakage portion is the positive power supply line P, the negative power supply line N, or the assembled batteries 2a to 2n in the potential difference V2x calculated by the earth leakage portion determination means. It is stored in the memory 51 as a discriminating element. Further, the storage means of the earth leakage determination unit 50 outputs the division result (= V2x / Vcell') of the earth leakage part determination means to all the battery cells 3a to 3n, 3a to 3n in which the earth leakage part is in the assembled batteries 2a to 2n. The battery cell is stored in the memory 51 as a discriminating element as to which battery cell it is.
Other configurations are the same as in the first embodiment.

The control executed by the leakage determination unit 50 is shown in the flowchart of FIG. Since the processing of steps S1 to S7 is the same as the control of the first embodiment, the description thereof will be omitted.

There is the following relationship between the potential difference V2 measured by the potential difference measuring unit 40 and the actual potential difference V2x between the leakage site and the earth G.
V2 = V2xxr / (R + r)
After turning on the switch in step S7, the earth leakage determination unit 50 is based on the potential difference V2 measured by the potential difference measurement unit 40, the resistance value R detected by the insulation resistance detection unit 30, and the resistance value which is known data. The actual potential difference V2x between the leakage site and the earth G is calculated by the calculation of the equation (step S7a).
V2x = V2x (R + r) / r
Subsequently, the leakage determination unit 50 calculates the average value Vcell'of all the cell voltage Vcells measured by each voltage measurement unit 4 in the battery power supply 1, and divides the calculated potential difference V2x by the average value Vcell'. (Step S8).

Then, the leakage determination unit 50 determines whether the leakage portion (the portion where the resistance value R is lowered) is the positive power supply line P or the negative power supply line N, or the assembled batteries 2a to 2n, based on the calculated potential difference V2x. The above division result (= V2x / Vcell') is stored in the memory 51 as a discriminating factor as to whether or not the leakage is true, and the leakage portion of all the battery cells 3a to 3n, 3a to 3n, ... It is stored in the memory 51 as an element for determining which battery cell it is (step S9).

Following this memory, the earth leakage determination unit 50 turns off the switch 41 of the potential difference measurement unit 40 (step S10). When the switch 41 is turned off, the operation of the potentiometric titration unit 40 is stopped. The judgment process ends.

As described above, the resistance is obtained by calculating the actual potential difference V2x that does not include the influence of the voltage drop due to the insulation resistance, and storing the calculated potential difference V2x and the division result (= V2x / Vcell') as the discrimination element of the leakage portion. Even if there is a voltage drop at the value R, it is possible to more accurately determine which battery cell the leakage site is, without being affected by it.

[3] Modification example
(1) In each of the above embodiments, the case where one end of the switch 41 of the potential difference measuring unit 40 is connected to the negative power supply line N has been described as an example, but one end of the switch 41 of the potential difference measuring unit 40 is connected to the positive power supply line P. Even when connected to, it is possible to accurately detect the presence or absence of an electric leakage and where the electric leakage site is.

In this case, if the leakage portion is the positive power supply line P, the potential difference V2 measured by the potential difference measuring unit 40 becomes zero (V2 = zero). If the leakage portion is the negative power supply line N, the potential difference V2 measured by the potential difference measuring unit 40 becomes the same value as the voltage Vb of the battery power supply 1 (V2 = Vb). If the leakage site is a battery cell of any of the assembled batteries 2a to 2n, the measured potential difference V2 measured by the potential difference measuring unit 40 is lower than the voltage Vb of the battery power supply 1 and higher than zero (Vb> V2>. zero). The number of the battery cell where the leakage portion is located is the position counted from the positive power supply line P.

(2) In each of the above embodiments, the switch 41 of the potential difference measuring unit 40 is turned on (the operation of the potential difference measuring unit 40 is started) on the condition that there is an electric leakage and the vehicle is stopped (YES in step S6). The switch 41 of the potential difference measuring unit 40 may be turned on under the three conditions of leakage, stopping the running of the vehicle, and turning off the ignition switch 61 (YES in step S6).

When the ignition switch 61 is turned off, the positive contact 5 and the negative contact 6 in the battery power supply 1 are opened by the vehicle control unit 60, so that the potential difference measuring unit 40 is in a state where the output of the battery power supply 1 is cut off. Starts working.

Even if the vehicle is stopped, as long as the ignition switch 61 is on, the power supply from the battery power supply 1 to the load continues via the DC / DC converter 12, so that the voltage Vb of the battery power supply 1 may fluctuate. However, by adding the off operation of the ignition switch 61 as a condition, the potential difference V2 can be measured in a state where the voltage Vb of the battery power supply 1 is stable. As a result, the leakage site can be detected more accurately.

(3) In each of the above embodiments, the potential difference V2 and the division result (= V2 / Vcell') or the potential difference V2x and the division result (= V2x / Vcell') are stored as a discrimination element of the leakage portion, and the actual discrimination is performed by the worker. Although the configuration is left to the determination of the above, the leakage determination unit 50 may automatically determine the leakage portion based on the discrimination element, and the determination result may be stored in the memory 51.

The worker can directly and easily recognize the leakage portion only by reading the determination result stored in the memory 51. You don't have to think about it. Even an inexperienced worker can accurately know the leakage site.

(4) In each of the above embodiments, the result of dividing the potential difference V2 or V2x by the average value Vcell'of all cell voltages Vcell is used as the discriminant element (V2 / Vcell'or V2x / Vcell') of the leakage site. , The ratio of the potential difference V2 or V2x to the voltage Vb of the battery power supply 1 is calculated by dividing the potential difference V2 or V2x by the voltage Vb of the battery power supply 1 (= V2 / Vb or V2x / Vb), and the battery power supply is divided into this ratio. By integrating the total number of constituent cells, it is possible to obtain a discriminating element of the leakage site. As a result, the leakage portion can be specified even for a vehicle in which the individual voltage V cells of the battery cells 3a to 3n are not measured.

(5) In addition, the above-described embodiments and modifications are presented as examples, and are not intended to limit the scope of the invention. This novel embodiment and modification can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the gist of the invention. These embodiments and modifications are included in the gist of the invention as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... Battery power supply (battery pack), 2a to 2n ... Batteries, 3a to 3n ... Battery cell, P ... Positive power supply line, N ... Negative power supply line, 5 ... Positive side contact, 6 ... Negative side contact, 10 ... Motor drive unit, 11 ... Motor, 12 ... DC / DC converter, 13 ... Charger, 20 ... Battery management unit (BMU), 21 ... Main control unit, 30 ... Insulation resistance detection unit (detection means), 31 ... AC Power supply, 34 ... Voltage detection unit, 40 ... Potential difference measurement unit (measurement means), 41 ... Switch, 42 ... Voltage meter, 50 ... Leakage determination unit, 51 ... Memory, 60 ... Vehicle control unit, 61 ... Ignition switch

Claims (5)

An earth leakage detection device for vehicles equipped with a battery power supply composed of a plurality of battery cells connected in series.
An insulation resistance detecting means for detecting the resistance value of the insulation resistance between the battery unit including the battery power supply and its peripheral portion and the ground of the vehicle, and
An electric leakage determining means for determining the presence or absence of electric leakage in the battery unit according to the detection result of the insulating resistance detecting means,
A potential difference between a battery voltage measuring means for measuring a battery voltage which is a total value of a plurality of battery cells and a potential difference for measuring a potential difference between the battery unit and the ground when the judgment result of the leakage determining means is leakage. Measuring means and
It is provided with a leakage site determining means for determining a leakage site based on the measurement result of the battery voltage measuring means when the potential difference measuring means measures the potential difference and the potential difference measured by the potential difference measuring means.
The potentiometric titration means includes a voltmeter for measuring the potentiometric titration between the battery unit and the ground.
The earth leakage portion determining means corrects the measurement result of the potential difference measuring means by calculation based on the detection result of the insulating resistance detecting means and the resistance value of the internal resistance of the voltmeter, and the measured result of the corrected potential difference measuring means. To determine which of the battery cells in the battery power source the leakage site is.
An earth leakage detection device characterized by this. The battery voltage measuring means measures individual cell voltages of the plurality of battery cells and calculates an average value of the plurality of cell voltages.
The earth leakage part determination means determines which of the battery cells in the battery power source the earth leakage part is by dividing the measurement result of the potential difference measuring means by the average value of the plurality of cell voltages. The leakage detection device according to claim 1. The leakage site determining means divides the measurement result of the potential difference measuring means by the measurement result of the battery voltage measuring means when the potential difference measuring means measures the potential difference, thereby dividing the measurement result of the potential difference measuring means with respect to the battery voltage, thereby causing the battery unit and the ground. By calculating the ratio of the potential difference between the two and the above ratio and integrating the total number of cells constituting the battery power supply into the ratio, it is determined which of the battery cells in the battery power supply the leakage portion is. The electric leakage detection device according to claim 1, wherein the leakage detection device is characterized. The potential difference measuring means is configured by connecting the voltmeter to the ground between either one of the positive power supply line and the negative power supply line derived from the battery power supply via a switch. The switch is turned off when the determination result of the leakage determination means is no leakage and turned on when there is leakage, and when the switch is turned on, either one of the positive power supply line and the negative power supply line and the ground are connected. The leakage detection device according to any one of claims 1 to 3 , wherein the potential difference between the two and the leakage portion is measured by the voltmeter as a discriminating element for the leakage portion. The potential difference measuring means according to any one of claims 1 to 4 , wherein the potential difference measuring means measures the potential difference when the determination result of the leakage determining means is leakage and the vehicle stops traveling. Leakage detector.

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