JP2021145422A - Power storage device - Google Patents

Abstract

To suppress the power consumption of a battery by a control unit that monitors the battery status.SOLUTION: A power storage device 1 includes a battery B, a control unit 41 that switches between a normal mode and a power saving mode, first and second paths L1 and L2 connected to a positive electrode terminal of the battery B, a first filter F1 connected to the first path L1, a second filter F2 that is connected to the second path L2 and has a larger time constant than the first filter F1, and comparators Comp1 and Comp2 that output start signals s1 and s2 when the first path L1 is connected to one of the input terminals via the first filter F1, the second path L2 is connected to the other input terminal via the second filter F2, and a difference between the voltage input to the one input terminal and the voltage input to the other input terminal is greater than or equal to a threshold value. When the start signal is input in the power saving mode, the control unit 41 switches from the power saving mode to the normal mode.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power storage device that monitors the state of a battery.

Some power storage devices include a control unit that monitors the state of the battery. Patent Document 1 is a related technique.

By the way, even when the ignition of the vehicle is off, there is a possibility that the electric power of the battery of the power storage device mounted on the vehicle is consumed by the electrical components such as lights and heaters, and the battery is charged by the external charger. Therefore, the battery may be over-discharged or over-charged.

Therefore, in the above-mentioned power storage device, when the state of the battery is constantly monitored so that the battery does not become over-discharged or over-charged, there is a concern that the power consumption of the battery by the control unit may increase.

JP 2015-197998

An object of one aspect of the present invention is to provide a power storage device capable of suppressing power consumption of a battery by a control unit that monitors the state of the battery.

The power storage device according to the present invention is connected to a battery, a control unit that switches between a normal mode for monitoring the state of the battery and a power saving mode that consumes less power than the normal mode, and a positive terminal of the battery. The first and second paths to be processed, the first filter connected to the first path, and the second filter connected to the second path and having a larger time constant than the first filter, one of them. The first path is connected to the input terminal of the above via the first filter, the second path is connected to the other input terminal via the second filter, and the voltage input to one input terminal and the other. When the difference from the voltage input to the input terminal of is equal to or greater than the threshold value, it is equipped with a comparator that outputs a start-up signal. Switch to mode.

As a result, the control unit can be operated in the normal mode only when the difference exceeds the threshold value due to the current flowing through the battery and it is necessary to monitor the state of the battery. Therefore, the control unit is always operated in the normal mode. Compared with the case, the power consumption of the battery can be suppressed.

Further, the power storage device according to the present invention has a first battery group in which a plurality of batteries are connected in series, and a second battery group in which a plurality of batteries are connected in series and connected in parallel to the first battery group. A first diode connected between the batteries of the first battery group and between the batteries of the first battery group and the first filter, and between the batteries of the first battery group and the second filter. Between the second diode, the third diode connected between the batteries of the second battery group and the first filter, and between the batteries of the second battery group and the second filter. It may be configured to include a fourth diode to be connected.

As a result, when a current flows through one of the battery groups, the power saving mode can be switched to the normal mode even when the difference corresponding to the battery group becomes equal to or larger than the threshold value.

Further, the control unit switches from the power saving mode to the normal mode after a predetermined time elapses in the power saving mode and when the start signal is not input, and in the normal mode, the battery voltage is set to the predetermined voltage. When the following occurs, it may be configured to prohibit the supply of electric power from the battery to the load.

This makes it possible to prevent the battery from being over-discharged when a weak current flows from the battery to the load or the battery spontaneously discharges in the power saving mode.

Further, when the control unit determines that the battery is not used in the normal mode, the control unit switches from the normal mode to the power saving mode.

As a result, the control unit can be operated in the power saving mode when the battery is not used, so that the control unit is always operated in the normal mode regardless of whether the battery is used or not. Battery power consumption can be reduced.

According to the present invention, it is possible to suppress the power consumption of the battery by the control unit that monitors the state of the battery.

It is a figure which shows an example of the power storage device of 1st Embodiment. It is a figure which shows an example of the voltage output from a filter. It is a flowchart which shows an example of the operation of a control part. It is a figure which shows an example of the power storage device of 2nd Embodiment.

Hereinafter, embodiments will be described in detail based on the drawings.

<First Embodiment>
FIG. 1 is a diagram showing an example of a power storage device according to the first embodiment.

The power storage device 1 shown in FIG. 1 is mounted on an industrial vehicle such as an electric forklift or a vehicle Ve such as an electric vehicle, and includes a battery B, an ammeter 2, a voltmeter 3, switches SW1 to SW3, and a battery control ECU ( It is equipped with an Electronic Control Unit) 4.

In addition to the power storage device 1, the vehicle Ve controls the operation of the motor M for traveling of the vehicle Ve, the inverter circuit Inv for driving the motor M, and the inverter circuit Inv, and the charger Ch provided outside the vehicle Ve. It is provided with a vehicle ECU 5 that communicates with.

The inverter circuit Inv includes a switch, and when the switch is repeatedly turned on and off, the DC power supplied from the battery B is converted into AC power and supplied to the motor M. Further, the inverter circuit Inv converts the AC power (regenerated power) supplied from the motor M into DC power and supplies it to the battery B by repeatedly turning the switch on and off.

The vehicle ECU 5 is configured to include a processor, a storage unit, and the like, and by changing the duty ratio of the control signal that controls the on / off of the switch of the inverter circuit Inv, the electric power supplied from the inverter circuit Inv to the battery B or The electric power supplied from the battery B to the inverter circuit Inv is changed. The function of the vehicle ECU 5 may be included in the function of the battery control ECU 4 to integrate the battery control ECU 4 and the vehicle ECU 5, and the battery control ECU 4 after the integration may be provided in the power storage device 1 or the vehicle Ve.

Battery B is composed of one or more secondary batteries such as a lithium ion battery or a nickel metal hydride battery. For example, the battery B may be composed of secondary batteries connected in parallel with each other. The positive terminal of the battery B is connected to the positive input terminal of the inverter circuit Inv. The negative terminal of the battery B is connected to the negative input terminal of the inverter circuit Inv via the ammeter 2 and the switches SW1 and SW2. Further, when the charger Ch is connected to the vehicle Ve via a charging cable or the like, the positive terminal of the battery B is connected to the positive terminal of the charger Ch, and the negative terminal of the battery B is the ammeter 2 and the switch SW1. It is connected to the negative terminal of the charger Ch via SW3.

The ammeter 2 is composed of a shunt resistor, an operational amplifier, a Hall element, or the like, detects a voltage corresponding to the current flowing through the battery B, and outputs the voltage to the battery control ECU 4. The battery control ECU 4 measures the current flowing through the battery B based on the voltage output from the ammeter 2.

The voltmeter 3 is composed of a voltage dividing resistor, an IC (Integrated Circuit), or the like, detects a voltage corresponding to the voltage across the battery B, and outputs the voltage to the battery control ECU 4. The battery control ECU 4 measures the voltage across the battery B based on the voltage output from the voltmeter 3.

The switches SW1 to SW3 are each composed of a semiconductor switch (for example, MOSFET (Metal Oxide Semiconductor Field Effect Transistor)), an electromagnetic relay, or the like. The switches SW1 to SW3 may be connected to the positive terminal side of the battery B.

When the switches SW1 and SW2 are electrically connected and the switch SW3 is cut off, the inverter circuit Inv can supply electric power to the battery B, and the battery B can supply electric power to the inverter circuit Inv. become. Further, when the charger Ch is connected to the vehicle Ve, the switches SW1 and SW3 are electrically connected, and when the switch SW2 is cut off, the battery B can be supplied with electric power from the charger Ch. When power is supplied to the battery B from the inverter circuit Inv or the charger Ch, the battery B is charged, the charge rate of the battery B (the ratio of the capacity of the battery B to the full charge capacity of the battery B) and the voltage increase, and the battery When power is supplied from B to the inverter circuit Inv, the battery B is discharged and the charge rate and voltage of the battery B decrease.

The battery control ECU 4 includes a first path L1, a second path L2, a filter F1 (first filter), a filter F2 (second filter), a comparator Comp1, a comparator Comp2, and a control unit 41. And.

One terminal of the first path L1 is connected to the positive terminal of the battery B, and the other terminal of the first path L1 is connected to the positive input terminal of the comparator Comp1 and the negative input terminal of the comparator Comp2 via the filter F1. ..

One terminal of the second path L2 is connected to the positive terminal of the battery B, and the other terminal of the second path L2 is connected to the negative input terminal of the comparator Comp1 and the positive input terminal of the comparator Comp2 via the filter F2. ..

The filter F1 includes a resistor R1 and a capacitor C1. That is, one terminal of the resistor R1 is connected to the positive terminal of the battery B, and the other terminal of the resistor R1 is connected to the one terminal of the capacitor C1, the positive terminal of the comparator Comp1, and the negative terminal of the comparator Comp2. The other terminal of the capacitor C1 is connected to the negative terminal of the battery B. When the current flowing from the inverter circuit Inv or the charger Ch to the battery B flows to the resistor R1 and the capacitor C1, or when the current flowing from the battery B to the inverter circuit Inv flows to the resistor R1 and the capacitor C1, the voltage V1 is released from the filter F1. It shall be output.

The filter F2 includes a resistor R2 and a capacitor C2. That is, one terminal of the resistor R2 is connected to the positive terminal of the battery B, and the other terminal of the resistor R2 is connected to the one terminal of the capacitor C2, the negative terminal of the comparator Comp1, and the positive terminal of the comparator Comp2. The other terminal of the capacitor C2 is connected to the negative terminal of the battery B. When the current flowing from the inverter circuit Inv or the charger Ch to the battery B flows to the resistor R2 and the capacitor C2, or when the current flowing from the battery B to the inverter circuit Inv flows to the resistor R1 and the capacitor C1, the voltage V2 is released from the filter F2. It shall be output. Further, the time constant of the filter F2 is larger than the time constant of the filter F1. Further, as long as the time constant of the filter F2 is larger than the time constant of the filter F1, the circuit configurations of the filters F1 and F2 are not particularly limited.

Here, FIG. 2 is a diagram showing an example of the voltage V1 output from the filter F1 and the voltage V2 output from the filter F2. The horizontal axis of the two-dimensional coordinates shown in FIG. 2 indicates time, the vertical axis indicates voltage, and the solid line indicates from the filter F1 when current starts to flow from the inverter circuit Inv or the charger Ch to the battery B at time t. The output voltage V1 is shown, and the broken line indicates the voltage V2 output from the filter F2 when a current starts to flow from the inverter circuit Inv or the charger Ch to the battery B at time t.

As described above, since the time constant of the filter F2 is larger than the time constant of the filter F1, the ratio of the change width of the voltage V2 per unit time is temporarily the change width of the voltage V1 per unit time after the time t. It becomes smaller than the ratio, and the difference ΔV between the voltage V1 and the voltage V2 becomes large.

The comparator Comp1 shown in FIG. 1 has a difference ΔV between the voltage V1 input to the positive input terminal and the voltage V2 input to the negative input terminal when a current is flowing from the inverter circuit Inv or the charger Ch to the battery B. When the threshold value becomes th1 or more, the start signal s1 is output from the output terminal to the input terminal in1 of the control unit 41. For example, the voltage V1 input to the positive input terminal of the comparator Comp1 when the current in the direction of charging the battery B flows through the first path L1 and the second path L2 is the voltage input to the negative input terminal of the comparator Comp1. When it becomes higher than V2, the start signal s1 output from the output terminal of the comparator Comp1 to the input terminal in1 of the control unit 41 changes from low level to high level. The control unit 41 determines that the start-up signal s1 has been input when the start-up signal s1 goes from Robel to a high level.

Comparator Comp2 is an output terminal when the difference ΔV between the voltage V1 input to the positive input terminal and the voltage V2 input to the negative input terminal becomes the threshold th2 or more when a current is flowing from the battery B to the inverter circuit Inv. Outputs the start signal s2 to the input terminal in2 of the control unit 41. For example, the voltage V1 input to the negative input terminal of the comparator Comp1 when the current in the direction of discharging the battery B flows through the first path L1 and the second path L2 is the voltage input to the positive input terminal of the comparator Comp1. When it becomes higher than V2, the start signal s2 output from the output terminal of the comparator Comp2 to the input terminal in2 of the control unit 41 changes from low level to high level. The control unit 41 determines that the start-up signal s2 has been input when the start-up signal s2 goes from Robel to a high level.

Either one of the comparators Comp1 and Comp2 may be omitted.

The control unit 41 is composed of a CPU (Central Processing Unit) or a programmable device (FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device)).

Further, in the normal mode, the control unit 41 measures the current flowing through the battery B based on the voltage output from the ammeter 2, and sets the voltage of the battery B based on the voltage output from the voltmeter 3. measure. That is, the control unit 41 monitors the state of the battery B in the normal mode.

Further, in the normal mode, the control unit 41 transmits the measured voltage and current to the vehicle ECU 5 by using CAN (Controller Area Network) communication or the like.

Further, the control unit 41 determines whether or not the voltage of the battery B is equal to or lower than the predetermined voltage in the normal mode. When the control unit 41 determines that the voltage of the battery B is equal to or lower than the predetermined voltage, the control unit 41 transmits a power stop instruction to the vehicle ECU 5 in order to prohibit the power from being supplied from the battery B to the load such as the inverter circuit Inv. When the power stop instruction is input, the vehicle ECU 5 shuts off the switch SW1 or stops the operation of the inverter circuit Inv. The predetermined voltage is the voltage of the battery B immediately before the battery B is in the over-discharged state. As a result, when the voltage of the battery B becomes equal to or lower than the predetermined voltage, the switch SW2 is cut off, or the operation of the inverter circuit Inv is stopped, it is prohibited to supply power from the battery B to the load such as the inverter circuit Inv. Therefore, it is possible to prevent the battery B from being over-discharged.

Further, the control unit 41 determines whether or not the battery B is used in the normal mode. For example, the control unit 41 determines that the battery B is used when the current flowing through the battery B is equal to or greater than the predetermined current, and when the current flowing through the battery B is smaller than the predetermined current, the battery B is not used. Judge.

In the normal mode, at least, a function for measuring the current flowing through the battery B, a function for measuring the voltage of the battery B, a function for determining whether or not the voltage of the battery B is equal to or lower than a predetermined voltage, and a function for determining whether or not the voltage of the battery B is equal to or lower than a predetermined voltage, and It is assumed that the battery B consumes the electric power for executing the function for determining whether or not the battery B is used in the control unit 41.

Further, the control unit 41 does not measure the current flowing through the battery B and the voltage of the battery B in the power saving mode. That is, the control unit 41 does not monitor the state of the battery B in the power saving mode.

Further, the control unit 41 switches from the power saving mode to the normal mode when the start signal s1 or the start signal s2 is input in the power saving mode.

Further, the control unit 41 repeatedly determines whether or not a predetermined time has elapsed in the power saving mode.

In the power saving mode, at least the power for operating the comparators Comp1 and Comp2, the function of determining whether or not the start signals s1 and s2 have been input, and whether or not a predetermined time has elapsed are repeatedly determined. It is assumed that the electric power for executing the function in the control unit 41 is consumed in the battery B.

Further, in the normal mode, various functions other than the above functions are executed by the control unit 41, so that the power of the battery B consumed in the power saving mode is the battery consumed in the normal mode. It shall be smaller than the power of B. Therefore, when the normal mode and the power saving mode are alternately and repeatedly executed, the power consumption of the battery B can be suppressed as compared with the case where only the normal mode is executed.

FIG. 3 is a flowchart showing an example of the operation of the control unit 41.

First, when the ignition of the vehicle Ve is turned off, the control unit 41 sets a normal mode as the operation mode of the control unit 41 (step S1).

Next, when the control unit 41 determines that the voltage of the battery B is equal to or lower than the predetermined voltage (step S2: Yes), the control unit 41 transmits a power stop instruction to the vehicle ECU 5 (step S3).

On the other hand, when the control unit 41 determines that the voltage of the battery B is larger than the predetermined voltage (step S2: No), the control unit 41 determines whether or not the battery B is used (step S4).

Next, when the control unit 41 determines that the battery B is being used (step S4: Yes), the control unit 41 continuously sets the normal mode as the operation mode of the control unit 41 (step S1).

On the other hand, when the control unit 41 determines that the battery B is not being used (step S4: No), the control unit 41 switches from the normal mode to the power saving mode as the operation mode of the control unit 41 (step S5).

Next, the control unit 41 switches from the normal mode to the power saving mode, and when the start signals s1 and s2 are not input (step S6: No) and the predetermined time has not elapsed (step). S7: No), the power saving mode is continuously set as the operation mode of the control unit 41 (step S5).

On the other hand, when one of the start signals s1 and s2 is input (step S6: Yes), or when the predetermined time elapses when the start signals s1 and s2 are not input, the control unit 41 (step S6). : No, step S7: Yes), the operation mode of the control unit 41 is switched from the power saving mode to the normal mode (step S1).

As described above, according to the power storage device 1 of the first embodiment, the difference ΔV between the voltage V1 output from the filter F1 and the voltage V2 output from the filter F2 due to the current flowing through the battery B is the thresholds th1 and th2. Only when it is necessary to monitor the state of the battery B as described above, the control unit 41 can be operated in the normal mode to consume the power of the battery B. Therefore, the control unit 41 is always operated in the normal mode to consume the battery. Compared with the case where the power of B is consumed, the power consumption of the battery B can be suppressed.

Further, according to the power storage device 1 of the first embodiment, in the power saving mode and when the start signals s1 and s2 are not input, when a predetermined time elapses, the power saving mode is switched to the normal mode. In the normal mode, when the voltage of the battery B becomes equal to or lower than the predetermined voltage, the battery B is prohibited from supplying power to the load such as the inverter circuit Inv. Therefore, in the power saving mode, the load is loaded from the battery B. It is possible to prevent the battery B from being over-discharged when a weak current flows through the battery or the battery B is spontaneously discharged.

Further, according to the power storage device 1 of the first embodiment, when it is determined that the battery B is not used in the normal mode, the battery B is not used because the configuration is such that the normal mode is switched to the power saving mode. At this time, since the control unit 41 can be operated in the power saving mode, the power consumption of the battery B can be reduced as compared with the case where the control unit 41 is always operated in the normal mode regardless of whether the battery B is used or not. It can be suppressed.

Further, according to the power storage device 1 of the first embodiment, it is not necessary to provide a high-performance battery control ECU with low power consumption, so that the manufacturing cost of the power storage device 1 can be suppressed.

<Second Embodiment>
FIG. 4 is a diagram showing an example of the power storage device of the second embodiment. In the power storage device 1 shown in FIG. 4, the same reference numerals are given to the same configurations as those shown in FIG. 1, and the description thereof will be omitted.

The power storage device 1 shown in FIG. 4 differs from the power storage device 1 shown in FIG. 1 in that a plurality of batteries B (batteries B1 to B4), a plurality of ammeters 2 (ammeters 21 and 22), and a plurality of voltages. A total of 3 (voltmeters 31 and 32) and a plurality of diodes D (voltmeters D1 to D4) are provided. When the batteries B1 to B4 are not particularly distinguished, they are simply referred to as batteries B. Further, when the ammeters 21 and 22 are not particularly distinguished, the ammeter 2 is simply used. Further, when the voltmeters 31 and 32 are not particularly distinguished, the voltmeter 3 is simply used. Further, the configurations of the ammeters 21 and 22, the voltmeters 31 and 32, the switches SW1 to SW3, and the battery control ECU 4 shown in FIG. 4 are the ammeter 2, the voltmeter 3, the switches SW1 to SW3, and the battery shown in FIG. The configuration is the same as that of the control ECU 4.

Like the battery B shown in FIG. 1, the batteries B1 to B4 are composed of one or more secondary batteries such as a lithium ion battery or a nickel hydrogen battery. The battery B1 and the battery B2 are connected in series with each other to form a first battery group. Further, the battery B3 and the battery B4 are connected in series with each other to form a second battery group. Further, the first battery group and the second battery group are connected to each other in parallel. That is, the positive terminal of the battery B1 is connected to the positive terminal of the battery B3 and the positive input terminal of the inverter circuit Inv, and the negative terminal of the battery B1 is connected to the positive terminal of the battery B2. The negative terminal of the battery B2 is connected to the negative terminal of the battery B4 via the ammeter 21 and the ammeter 22, and is also connected to the negative input terminal of the inverter circuit Inv via the ammeter 21 and the switches SW1 and SW2. .. The negative terminal of the battery B3 is connected to the positive terminal of the battery B4. Further, when the charger Ch is connected to the vehicle Ve via a charging cable or the like, the positive terminal of the battery B1 and the positive terminal of the battery B3 are connected to the positive terminal of the charger Ch, and the negative terminal of the battery B2 is the current. The negative terminal of the charger Ch is connected to the negative terminal of the charger Ch via the total 21 and the switches SW1 and SW3, and the negative terminal of the battery B4 is connected to the negative terminal of the charger Ch via the current meter 22 and the switches SW1 and SW3. The number of batteries B connected in series with each other and the number of battery groups connected in parallel with each other are not particularly limited. Further, the numbers of the ammeter 2, the voltmeter 3, and the diode D shall be determined according to the number of battery groups connected in parallel to each other.

The batteries B1 and B2 of the first battery group and the filter F1 (first filter) are connected via a diode D1 (first diode), and the batteries B1 and B2 of the first battery group and the filter F2 are connected. (Second filter) is connected via diode D2 (second diode), and between batteries B3 and B4 of the second battery group and filter F1 (first filter) is diode D3 (third filter). It is connected via a diode), and the batteries B3 and B4 of the second battery group and the filter F2 (second filter) are connected via a diode D4 (fourth diode). That is, the anode terminal of the diode D1 is connected to the connection point between the negative terminal of the battery B1 and the positive terminal of the battery B2, and the cathode terminal of the diode D1 is connected to one terminal of the resistor R1 of the filter F1. Further, the anode terminal of the diode D2 is connected to the connection point between the negative terminal of the battery B1 and the positive terminal of the battery B2, and the cathode terminal of the diode D2 is connected to one terminal of the resistor R2 of the filter F2. Further, the anode terminal of the diode D3 is connected to the connection point between the negative terminal of the battery B3 and the positive terminal of the battery B4, and the cathode terminal of the diode D3 is connected to one terminal of the resistor R1 of the filter F1. Further, the anode terminal of the diode D4 is connected to the connection point between the negative terminal of the battery B3 and the positive terminal of the battery B4, and the cathode terminal of the diode D4 is connected to one terminal of the resistor R2 of the filter F2. By connecting the batteries B and the filters F1 and F2 via the diodes D1 to D4 in this way, the current flowing through the first battery group and the current flowing through the second battery group do not merge. , Since the current flowing through the first and second battery groups can be passed through the filter F1 or the filter F2, respectively, whether or not the current is flowing through the first battery group and whether the current is flowing through the second battery group Whether or not it can be determined individually. The position between the batteries B to which the anode terminal of the diode D is connected is not particularly limited as long as the diode D can be turned on when a current flows between the batteries B.

The comparator Comp1 outputs a start signal s1 when the difference ΔV becomes the threshold value th1 or more when a current is flowing from the inverter circuit Inv or the charger Ch to at least one of the first and second battery groups. When the start signal s1 is input in the power saving mode, the control unit 41 switches from the power saving mode to the normal mode.

The comparator Comp2 outputs a start signal s2 when the difference ΔV becomes the threshold value th2 or more when a current is flowing through the inverter circuit Inv from at least one of the first and second battery groups. When the start signal s2 is input in the power saving mode, the control unit 41 switches from the power saving mode to the normal mode.

Either one of the comparators Comp1 and Comp2 may be omitted. Further, the diodes D1 to D4 may be omitted, and the power storage device 1 may be provided with comparators Comp1 and Comp2 corresponding to the first and second battery groups, respectively.

The control unit 41 monitors the status of the batteries B1 to B4 (first and second battery groups) in the normal mode. That is, in the normal mode, the control unit 41 measures the current flowing through the batteries B1 and B2 (first battery group) based on the voltage output from the current meter 21, and sets the voltage output from the current meter 22. Based on this, the current flowing through the batteries B3 and B4 (second battery group) is measured. Further, the control unit 41 measures the voltage of the batteries B1 and B2 based on the voltage output from the voltmeter 31, and measures the voltage of the batteries B3 and B4 based on the voltage output from the voltmeter 32.

Further, the control unit 41 determines whether or not the voltage of at least one battery B among the batteries B1 to B4 is equal to or lower than a predetermined voltage in the normal mode. When the control unit 41 determines that the voltage of at least one battery B among the batteries B1 to B4 is equal to or lower than a predetermined voltage, the control unit 41 prohibits the supply of electric power from the battery B to a load such as the inverter circuit Inv. The power stop instruction is transmitted to the vehicle ECU 5. When the power stop instruction is input, the vehicle ECU 5 shuts off the switch SW1 or stops the operation of the inverter circuit Inv. The predetermined voltage is the voltage of the battery B immediately before the battery B is in the over-discharged state. As a result, when the voltage of at least one battery B among the batteries B1 to B4 becomes equal to or lower than a predetermined voltage and the switch SW2 is shut off or the operation of the inverter circuit Inv is stopped, the inverter circuit Inv or the like from the batteries B1 to S4 or the like. Since it is prohibited to supply electric power to the load of the above, it is possible to prevent the batteries B1 to B4 from being over-discharged.

Further, the control unit 41 determines whether or not the first and second battery groups are used in the normal mode. For example, when the current flowing through the first battery group is equal to or greater than a predetermined current, the control unit 41 determines that the first battery group is being used, and the current flowing through the first battery group is smaller than the predetermined current. In this case, it is determined that the first battery group is not used. Further, when the current flowing through the second battery group is equal to or greater than the predetermined current, the control unit 41 determines that the second battery group is being used, and the current flowing through the second battery group is smaller than the predetermined current. In this case, it is determined that the second battery group is not used.

In the normal mode, at least the function for measuring the current flowing through the first and second battery groups, the function for measuring the voltage of the batteries B1 to B4, and the voltage of the batteries B1 to B4 are equal to or less than the predetermined voltage. The batteries B1 to B4 consume power for executing the function of determining whether or not the batteries are present and the function of determining whether or not the first and second battery groups are used in the control unit 41. Shall be.

Further, the control unit 41 does not measure the current flowing through the first and second battery groups and the voltages of the batteries B1 to B4 in the power saving mode. That is, the control unit 41 does not monitor the status of the batteries B1 to B4 in the power saving mode.

Further, when the start signal s1 or the start signal s2 is input, the control unit 41 switches from the power saving mode to the normal mode.

In the power saving mode, the control unit 41 executes at least a function for operating the comparators Comp1 and Comp2 and a function for determining whether or not the start signals s1 and s2 have been input. It is assumed that the power of the batteries B and Ba is consumed in order to execute the function.

Further, it is assumed that the power of the battery B consumed in the power saving mode is smaller than the power of the battery B consumed in the normal mode. Therefore, when the normal mode and the power saving mode are alternately and repeatedly executed, the power consumption of the battery B can be suppressed as compared with the case where only the normal mode is executed.

As described above, according to the power storage device 1 of the second embodiment, since the batteries B and the filters F1 and F2 are connected to each other via the diodes D1 to D4, the first and second battery groups When a current flows through one of the battery groups, the power saving mode can be switched to the normal mode even when the difference ΔV corresponding to the current flowing through the battery group becomes the thresholds th1 and th2 or more.

Further, according to the power storage device 1 of the second embodiment, the control unit 41 is operated in the normal mode only when the difference ΔV becomes the thresholds th1 and th2 or more and it is necessary to monitor the state of the battery group. Since the power of the second battery group can be consumed, the first and second battery groups are consumed as compared with the case where the control unit 41 is always operated in the normal mode and the power of the first and second battery groups is consumed. The power consumption of the battery group can be suppressed.

Further, the power storage device 1 of the second embodiment switches from the power saving mode to the normal mode after a predetermined time elapses when the power saving mode is in the power saving mode and the start signals s1 and s2 are not input, and the normal mode is set. At this time, when the voltage of at least one of the batteries B1 to B4 becomes equal to or lower than a predetermined voltage, the electric power is prohibited from being supplied from the batteries B1 to B4 to the load such as the inverter circuit Inv. Therefore, in the power saving mode, it is possible to prevent the batteries B1 to B4 from being over-discharged when a weak current flows from the batteries B1 to B4 to the load or the batteries B1 to B4 spontaneously discharge. can.

Further, the power storage device 1 of the second embodiment has a configuration of switching from the normal mode to the power saving mode when it is determined that the first and second battery groups are not used in the normal mode. Therefore, when the first and second battery groups are not used, the control unit 41 can be operated in the power saving mode, and control is performed regardless of whether or not the first and second battery groups are used. Compared with the case where the unit 41 is always operated in the normal mode, the power consumption of the batteries B1 to B4 can be suppressed.

Further, according to the power storage device 1 of the second embodiment, unlike the power storage device 1 of the first embodiment, it is not necessary to provide a high-performance battery control ECU with low power consumption, so that the manufacturing cost of the power storage device 1 can be reduced. It can be suppressed.

Further, according to the power storage device 1 of the second embodiment, at least a relatively low voltage capable of turning on the diode D can be input to the comparators Comp1 and Comp2 via the filters F1 and F2, so that the cost is low. Comparator Comp1 and Comp2 can be adopted, and the manufacturing cost of the power storage device 1 can be suppressed.

<Other operations of the control unit 41 and the vehicle ECU 5 in FIG. 1 or 4>
When the control unit 41 receives a signal indicating that the ignition is switched from the ignition off to the ignition on by the operation of the ignition switch by the user, the control unit 41 sends the input power command value Win or the output power command value Wout according to the charge rate of the battery B to the vehicle ECU 5. Send. Further, when the vehicle ECU 5 switches from the ignition off to the ignition on by the operation of the ignition switch by the user, the switches SW1 and SW2 are switched from the cutoff state to the conduction state, and the switch SW3 is left in the cutoff state.

Further, when the charge rate of the battery B becomes equal to or less than the first lower limit threshold value, the control unit 41 transmits the limited output power command value Wout to the vehicle ECU 5, and when the charge rate becomes equal to or higher than the first upper limit threshold value. The input power command value Win after the limitation is transmitted to the vehicle ECU 5. The vehicle ECU 5 controls the operation of the inverter circuit Inv so that the power corresponding to the output power command value Wout is supplied from the battery B to the inverter circuit Inv, and the power corresponding to the input power command value Win is supplied from the inverter circuit Inv. The operation of the inverter circuit Inv is controlled so as to be supplied to the battery B. When the output power command value Wout or the input power command value Win is limited, the vehicle ECU 5 reduces the duty ratio of the control signal that controls the on / off of the switch of the inverter circuit Inv, thereby reducing the duty ratio of the control signal from the battery B to the inverter circuit Inv. The power supplied to the battery B or the power supplied from the inverter circuit Inv to the battery B is limited.

Further, instead of steps S2 and S3 shown in FIG. 3, the control unit 41 causes the charge rate of the battery B to be smaller than the first lower limit threshold and equal to or less than the second lower limit threshold, or the charge rate is the first. When the power exceeds the second upper limit threshold, which is larger than the upper limit threshold, power is supplied from the battery B to the inverter circuit Inv by shutting off the switches SW1, SW2, and SW3, and power is supplied from the inverter circuit Inv to the battery B. It may be configured to transmit a power stop instruction to the vehicle ECU 5 in order to prohibit the power from being supplied to the battery B from the charger Ch. The second lower threshold value is the charge rate of the battery B immediately before the battery B is in the overcharged state, and the second upper limit threshold value is the charge rate of the battery B immediately before the battery B is in the overcharged state. .. As a result, it is possible to prevent the battery B from being in an overcharged state or an overdischarged state.

Further, in the control unit 41, instead of steps S2 and S3 shown in FIG. 3, when the switch SW1 and the switch SW2 or the switch SW1 and the switch SW3 are conducting, the voltage output from the ammeter 2 is equal to or higher than the overcurrent threshold. When the voltage becomes equal to or higher than the overvoltage threshold value, or when the voltage output from the voltmeter 3 becomes equal to or higher than the overvoltage threshold value, it may be determined that an abnormality has occurred in the battery B, and a power stop instruction may be transmitted to the vehicle ECU 5.

Further, when the vehicle ECU 5 receives the fact that the ignition is switched from the ignition on to the ignition off by the operation of the ignition switch by the user, the switches SW1 and SW2 are switched from the conductive state to the cutoff state, and the switch SW3 is left in the cutoff state.

Further, when the vehicle ECU 5 receives the charging start instruction of the battery B after the charger Ch and the vehicle Ve are connected via the charging cable, the switches SW1 and SW3 are made conductive and the switch SW2 is cut off to shut off the battery. A current command value corresponding to the charging rate of B is transmitted to the charger Ch.

The present invention is not limited to the above embodiments, and various improvements and changes can be made without departing from the gist of the present invention.

1 Power storage device 2, 21, 22 Ammeter 3, 31, 32 Voltmeter 4 Battery control ECU
41 Control unit 5 Vehicle ECU
Ve Vehicle Inv Inverter Circuit M Motor Ch Charger SW1, SW2, SW3 Switch B, B1-B4 Battery F1, F2 Filter R1, R2 Resistance C1, C2 Capacitor Comp1, Comp2 Comparator

Claims (4)

Batteries and
A control unit that switches between a normal mode for monitoring the state of the battery and a power saving mode that consumes less power than the normal mode.
The first and second paths connected to the positive terminal of the battery,
With the first filter connected to the first path,
A second filter connected to the second path and having a larger time constant than the first filter,
The first path is connected to one input terminal via the first filter, the second path is connected to the other input terminal via the second filter, and the second path is connected to the one input terminal. When the difference between the input voltage and the voltage input to the other input terminal is equal to or greater than the threshold value, a comparator that outputs a start signal and a comparator that outputs a start signal,
With
The control unit is a power storage device that switches from the power saving mode to the normal mode when the start signal is input in the power saving mode. The power storage device according to claim 1.
A first battery group in which a plurality of the batteries are connected in series, and
A second battery group in which a plurality of the batteries are connected in series and connected in parallel to the first battery group,
A first diode connected between the batteries of the first battery group and between the first filter,
A second diode connected between the batteries of the first battery group and between the second filter,
A third diode connected between the batteries of the second battery group and between the first filter,
A power storage device including a fourth diode connected between the batteries of the second battery group and between the second filter. The power storage device according to claim 1 or 2.
The control unit switches from the power saving mode to the normal mode when a predetermined time elapses in the power saving mode and when the start signal is not input, and in the normal mode, the battery A power storage device characterized in that when the voltage of the battery falls below a predetermined voltage, power is prohibited from being supplied to the load from the battery. The power storage device according to any one of claims 1 to 3.
A power storage device characterized in that the control unit switches from the normal mode to the power saving mode when it determines that the battery is not used in the normal mode.

Images