JP7031301B2 - Power storage element management device and management method - Google Patents

Description

The technique disclosed in the present specification relates to a management device for a power storage element and a management method.

Conventionally, in a management device that manages an in-vehicle power storage element used for starting a vehicle engine and supplying electric power to an in-vehicle device, it operates in the normal mode while the engine is operating, and consumes more power than the normal mode when the engine is stopped. It is known that the mode shifts to less power saving mode (see, for example, Patent Document 1).
Specifically, the battery management device (BMS) described in Patent Document 1 operates in a normal mode while the engine is operating, and consumes less power than the normal mode when the engine is stopped (corresponding to a power saving mode). ). Then, when the battery management device receives the ignition on signal after receiving the engine start signal from the ECU of the vehicle during the sleep mode, it determines that the engine is operating and switches to the normal mode. That is, the battery management device shifts to the normal mode when the engine operates during the sleep mode.

Japanese Unexamined Patent Publication No. 2014-96975

Since power is supplied from the power storage element to the in-vehicle device in the power saving mode, the state of the power storage element changes significantly in a short time during the power saving mode depending on the power usage status of the in-vehicle device. However, conventionally, it has not been sufficiently studied that the state of the power storage element changes significantly in a short time during the power saving mode, and there is room for improvement in properly managing the power storage element.

This specification discloses a technique capable of appropriately managing a power storage element while suppressing power consumption of the power storage element.

The power storage element management device disclosed in the present specification is a power storage element management device used for starting a power source and supplying electric power to a device, and includes a measuring unit for measuring a physical quantity related to the state of the power storage element. The management unit includes a management unit that manages the power storage element, and the management device measures the physical quantity in a first mode in which the measurement unit measures the physical quantity in a predetermined cycle and a cycle longer than the predetermined cycle. It has a second mode, and when the first predetermined condition regarding the power source is satisfied, the management unit operates the management device in the second mode, and the storage element is related to the power storage element during the second mode. When the second predetermined condition is satisfied, the management device is shifted to the first mode even if the first predetermined condition is satisfied.

According to the above management device, the power storage element can be appropriately managed while suppressing the power consumption of the power storage element.

Schematic diagram showing a vehicle and a battery according to the first embodiment Battery perspective An exploded perspective view of the battery Battery schematic Circuit diagram of interrupt circuit Graph for explaining the relationship between time and voltage and the operation mode Schematic diagram for explaining the transition of the operation mode

(Outline of this embodiment)
The power storage element management device disclosed in the present specification is a power storage element management device used for starting a power source and supplying electric power to a device, and includes a measuring unit for measuring a physical quantity related to the state of the power storage element. The management unit includes a management unit that manages the power storage element, and the management device measures the physical quantity in a first mode in which the measurement unit measures the physical quantity in a predetermined cycle and a cycle longer than the predetermined cycle. It has a second mode, and when the first predetermined condition regarding the power source is satisfied, the management unit operates the management device in the second mode, and the storage element is related to the power storage element during the second mode. When the second predetermined condition is satisfied, the management device is shifted to the first mode even if the first predetermined condition is satisfied.

If the state of the power storage element estimated from the above-mentioned physical quantity changes significantly in a short time, if the cycle for measuring the physical quantity is long, the next measurement was performed even if there is no abnormality in the state of the power storage element at the time of this measurement. Occasionally, it may happen that the power storage element is already in an abnormal state. Therefore, when the state of the power storage element changes significantly in a short time during the second mode, in order to properly manage the power storage element, even if the first predetermined condition is satisfied, the first mode is selected. It is desirable to make the transition and measure the physical quantity in a short cycle.
In addition, if an abnormality in the power storage element is detected based on the above-mentioned physical quantity, it may be misjudged if the abnormality is detected once and then immediately determined to be an abnormality. It is desirable to judge. In that case, if the cycle for measuring the physical quantity is long, it takes time for the abnormality to be detected a plurality of times, and there is a possibility that the response to the abnormality is delayed. Therefore, when an abnormality of the power storage element is detected during the second mode, in order to determine at an early stage whether or not the power storage element is abnormal, in other words, in order to properly manage the power storage element, the first method is used. Even if the predetermined conditions are satisfied, it is desirable to shift to the first mode and measure the physical quantity in a short cycle.
As described above, even if the first predetermined condition is satisfied, it may be desirable to shift the management device to the first mode in order to appropriately manage the power storage element.
According to the above management device, when the first predetermined condition is satisfied, the operation is performed in the second mode, so that the power consumption of the power storage element can be suppressed. Then, when the second predetermined condition regarding the power storage element is satisfied during the second mode, the mode shifts to the first mode even if the first predetermined condition is satisfied, so that the power storage element can be appropriately managed. Therefore, according to the above management device, the power storage element can be appropriately managed while suppressing the power consumption of the power storage element.

The first predetermined condition may be that the power source is stopped.

When the power source is stopped, the power storage element is not charged, so if the physical quantity is measured in a short cycle, the power of the power storage element is consumed quickly. According to the above management device, when the power source is stopped, the operation is performed in the second mode, so that the power consumption of the power storage element can be suppressed.

The second predetermined condition is at least one of the measurement of the physical quantity equal to or higher than the first reference value by the measuring unit and the measurement of the physical quantity equal to or lower than the second reference value. good.

Some physical quantities related to the state of the power storage element are proportional to the amount of change in the state of the power storage element per unit time. For example, the current value is an example. In the case of such a physical quantity, when a physical quantity equal to or higher than the first reference value is measured, it is desirable to measure the physical quantity in a short cycle, assuming that the state of the power storage element changes significantly in a short time.
In the case of a physical quantity that is not proportional to the amount of change in the state of the power storage element per unit time, when a physical quantity equal to or higher than the first reference value is measured or when a physical quantity equal to or lower than the second reference value is measured. It may be desirable to measure the physical quantity in a short cycle because an abnormality in the power storage element is foreseen. For example, voltage value and temperature are examples.
According to the above management device, in the case of a physical quantity proportional to the amount of change in the state of the power storage element per unit time, the state of the power storage element changes significantly in a short time when a physical quantity equal to or higher than the first reference value is measured. By shifting to the first mode, the power storage element can be appropriately managed. In the case of a physical quantity that is not proportional to the amount of change in the state of the power storage element per unit time, it is abnormal if a physical quantity equal to or higher than the first reference value is measured or a physical quantity equal to or lower than the second reference value is measured. By shifting to the first mode on the assumption that is foreseen, the power storage element can be appropriately managed.

The management unit estimates the state of the power storage element based on the physical quantity, and the second predetermined condition may be that the amount of change in the state per unit time is equal to or greater than the third reference value. ..

According to the above management device, when the amount of change in the state of the power storage element per unit time is larger than the third reference value, it is assumed that the state of the power storage element has changed significantly in a short time, and the mode shifts to the first mode. Therefore, the power storage element can be appropriately managed.

The management unit may detect an abnormality in the power storage element based on the physical quantity, and the second predetermined condition may be that the abnormality is detected.

According to the above management device, when an abnormality is detected, the mode shifts to the first mode even if the first predetermined condition is satisfied, so that the next physical quantity can be measured at an early stage. Therefore, it can be determined at an early stage whether or not it is abnormal, and the abnormality can be dealt with at an early stage.

The physical quantity is a current value of a current flowing through the power storage element, and the second predetermined condition may be that a current value equal to or higher than the first reference value is measured by the measuring unit.

Since the current value is highly related to the state of the power storage element, such as being used for estimating the charge state of the power storage element, the power storage element can be appropriately managed by using the current value as a physical quantity.

The management device includes a circuit breaker connected in series with the power storage element, has a third mode of opening the circuit breaker to cut off the current, and the physical quantity is the current value of the current flowing through the power storage element. , And the voltage value of the power storage element, and when the control unit measures a voltage value equal to or less than the fourth reference value by the measurement unit during the second mode, the management unit uses the management device as the third. You may shift to the mode of.

According to the above management device, the physical quantity used for determining the transition differs between when the second mode is changed to the first mode and when the second mode is changed to the third mode, so the mode is changed. Whether or not it can be appropriately determined according to the mode of the migration destination.

The management unit may shift the management device to the first mode when the charger is connected to the power storage element during the third mode.

When the management device is in the third mode, the circuit breaker is open and the power source cannot be started. In that case, for example, it is conceivable that the management device is provided with a switch and the driver of the power source operates the switch to shift the management device to the first mode. However, not all drivers know that the switch should be operated, and a driver who does not know this may not be able to start the power source and may be confused. On the other hand, since many drivers know that a charger should be connected when the battery is dead, it is more likely that the power source can be started than when operating a switch.

The method of managing a power storage element disclosed in the present specification is a method of managing a power storage element using a power storage element management device used for starting a power source and supplying electric power to an apparatus, and the management device is the above-mentioned management device. It has a first mode for measuring a physical quantity related to a state of a power storage element in a predetermined cycle and a second mode for measuring the physical quantity in a cycle longer than the predetermined cycle, and the management method relates to the power source. When the first predetermined condition is satisfied, the first step of operating the management device in the second mode, and when the second predetermined condition regarding the power storage element is satisfied during the second mode, the first. The present invention includes a second step of shifting the management device to the first mode even if the predetermined condition of the above is satisfied.

According to the above management method, the power storage element can be appropriately managed while suppressing the power consumption of the power storage element.

The invention disclosed herein can be realized in various aspects such as a control device, a control method, a computer program for realizing the functions of these methods or devices, a recording medium on which the computer program is recorded, and the like. ..

<Embodiment 1>
The first embodiment will be described with reference to FIGS. 1 to 7. In the following description, when referring to FIGS. 2 and 3, the vertical direction of the battery case 11 in a state where the battery case 11 is placed horizontally without tilting with respect to the installation surface is the Y direction, and the long side of the battery case 11 is used. The direction along the direction will be described as the X direction, and the depth direction of the battery case 11 will be described as the Z direction.

(1) Battery Configuration In FIG. 1, vehicle 2 is an engine vehicle having a gasoline engine or a diesel engine. The battery 1 is mounted on the vehicle 2, and is charged by a generator (alternator) powered by the engine of the vehicle 2 (an example of a power source) to start an engine, such as a starter or an in-vehicle device (headlight or audio). , Air conditioner, etc.). In-vehicle equipment is an example of equipment.

As shown in FIG. 2, the battery 1 includes a block-shaped battery case 11. The battery case 11 has a box-shaped case main body 13 that opens upward, an inner lid 15 that is attached to the upper part of the case main body 13, and an upper lid 16 that is attached to the upper part of the inner lid 15. As shown in FIG. 3, the battery case 11 has a battery module 20 in which a plurality of battery cells 21 (an example of a power storage element) are connected in series, a positioning member 14 for positioning the plurality of battery cells 21, and a management unit 31 (described later). A control board 18 or the like on which (see FIG. 4) is mounted is housed.

In the case main body 13, a plurality of cell chambers 13A in which each battery cell 21 is individually housed are provided side by side in the X direction. A plurality of bus bars 17 are arranged on the upper surface of the positioning member 14, and the plurality of battery cells 21 are positioned by arranging the positioning member 14 on the upper portion of the plurality of battery cells 21 housed in the cell chamber 13A. At the same time, a plurality of battery cells 21 are connected in series by a plurality of bus bars 17.

The inner lid 15 has a substantially rectangular shape in a plan view, and has a height difference in the Y direction. A positive electrode external terminal 12P and a negative electrode external terminal 12N to which a harness terminal (not shown) is connected are provided at both ends of the inner lid 15 in the X direction. The control board 18 is housed inside the inner lid 15, and the battery module 20 and the control board 18 are connected by mounting the inner lid 15 on the case body 13.

(2) Electrical Configuration of Battery The electrical configuration of the battery 1 will be described with reference to FIG. The battery 1 includes a battery module 20 and a battery management device 30 (BMS: Battery Management System) that manages the battery module 20. In the following description, the battery management device 30 will be referred to as a BMS 30. The BMS 30 is an example of a power storage element management device.

As described above, the battery module 20 has a plurality of battery cells 21 connected in series. Each battery cell 21 is a rechargeable secondary battery, specifically, for example, a lithium ion battery. The battery module 20 may be one in which a plurality of battery cells 21 are connected in parallel, or may be one in which a plurality of battery cells 21 are connected in combination of series and parallel. The connection form of the plurality of battery cells 21 can be appropriately determined.

The BMS 30 is operated by the electric power supplied from the battery cell 21, and includes a management unit 31, a current sensor 32 (an example of a measurement unit), a voltage sensor 33, a temperature sensor 34, and a relay 35 (an example of a circuit breaker). I have.
The management unit 31 includes a CPU 31A, a ROM 31B, a RAM 31C, a communication unit 31D, an interrupt circuit 31E, and the like. Various programs and data are stored in the ROM 31B. The CPU 31A controls each part of the battery 1 by executing a program stored in the ROM 31B.

The communication unit 31D is for communicating with the ECU mounted on the vehicle 2. The signals received from the ECU by the management unit 31 include the ignition on signal transmitted when the ignition switch of the vehicle 2 is in the ignition on position, the engine start signal transmitted when the engine start position is in the engine start position, and the accessory position. Includes accessory signals sent when, lock signals sent when in the locked position, and so on.

The interrupt circuit 31E is a circuit that applies a starting voltage to the CPU 31A when an external charger is connected to the battery 1. As shown in FIG. 5, one end of the interrupt circuit 31E is connected to the current path 36, and the other end is grounded. The interrupt circuit 31E has a relay 41, a voltage dividing resistor 42, and a voltage dividing resistor 43 connected in series, and a signal line 44 branched from between the two voltage dividing resistors 42 and 43 is a predetermined input port of the CPU 31A. It is connected to the.

The relay 41 is a latch type that maintains the switched state even when the power supply is stopped, and is opened and closed by the CPU 31A. As will be described in detail later, the operation mode of the BMS 30 includes a deep sleep mode. In the deep sleep mode, the CPU 31A stops operating. The CPU 31A closes the relay 41 when shifting to the deep sleep mode, resumes operation when a starting voltage is applied to the input port during the deep sleep mode, and opens the relay 41.

As shown in FIG. 4, the current sensor 32 is provided in series with the battery module 20. The current sensor 32 determines the current value I [A] of the charging current flowing from the alternator to the battery module 20 during charging, and the current value I [A] of the discharging current flowing from the battery module 20 to the starter of the vehicle 2 or the in-vehicle device during discharging. It measures and outputs to the management unit 31. In the following description, when the charge current and the discharge current are not distinguished, they are called charge / discharge currents. The current value is an example of a physical quantity.

The voltage sensor 33 is connected in parallel to both ends of each battery cell 21. The voltage sensor 33 measures the voltage value V [V], which is the terminal voltage of each battery cell 21, and outputs it to the management unit 31.
The temperature sensor 34 is provided in any one battery cell 21, measures the temperature [° C.] of the battery cell 21, and outputs the temperature [° C.] to the management unit 31. The temperature sensor 34 may be provided in each of two or more battery cells 21. Further, a plurality of temperature sensors 34 may be provided in one battery cell 21.

The relay 35 is provided in series with the battery module 20. The relay 35 is for cutting off the current path 36 when the battery cell 21 is foreseen to be overcharged or overdischarged, or when the deep sleep mode described later is entered. The relay 35 is a latch type and is opened and closed by the management unit 31.

(3) Management of battery cell There are various types of management of the battery cell 21, such as protection of the battery and response to an abnormality. Here, protection of the battery will be described.
The management unit 31 estimates the charge state (SOC: State Of Charge) of the battery cell 21, and if overcharge or overdischarge is predicted, the relay 35 is opened to protect the battery cell 21 from overcharge or overdischarge. Here, the current integration method will be described as an example as a method for estimating SOC.

The current integration method is a method of measuring the amount of electric power flowing in and out of the battery cell 21 by constantly measuring the charge / discharge current of the battery cell 21, and estimating the SOC by adding or subtracting this from the initial capacity. The current integration method has the advantage that the SOC can be estimated even while the battery cell 21 is in use, but on the other hand, since the current is constantly measured and the charge / discharge power amount is integrated, the measurement error of the current sensor 32 may accumulate and become gradually inaccurate. There is.

Therefore, the management unit 31 utilizes the fact that there is a relatively accurate correlation between the voltage across the battery cell 21 (OCV: Open Circuit Voltage) and the SOC when the current value is equal to or less than the reference value. The SOC estimated by the current integration method is reset based on the voltage across the battery cell 21.
Specifically, the management unit 31 measures the OCV of the battery cell 21 and identifies the SOC corresponding to the measured OCV by referring to the correlation between the OCV and the SOC stored in advance. Then, the management unit 31 resets the SOC estimated by the current integration method with the specified SOC. When the SOC is reset, the accumulation of errors in the current integration method is cut off, so that the estimation accuracy of the SOC can be improved.

The voltage across the above-mentioned voltage is not limited to the voltage across the voltage when the current value is equal to or less than the reference value, and the amount of voltage change per unit time of the battery module 20 when the current value is equal to or less than the reference value is equal to or less than a predetermined specified amount. It may be the voltage across the battery module 20 when the condition is satisfied.

(4) BMS operation mode and switching of operation mode Next, with reference to FIG. 6, the operation mode of the BMS 30 and the switching of the operation mode will be described. In FIG. 6, the solid line 45 shows the change in the voltage of the battery cell 21. The non-reusable voltage value (for example, 0.5 V) is a voltage at which reuse of the battery cell 21 is prohibited when the voltage drops further.

As shown in FIG. 6, the operation modes of the BMS 30 include a normal mode (an example of a first mode), a sleep mode (an example of a second mode), and a deep sleep mode (an example of a third mode). .. The management unit 31 appropriately manages the battery cell 21 while suppressing a decrease in the voltage of the battery cell 21 (in other words, the power consumption of the battery cell 21). Switch between these modes according to the above. Hereinafter, a specific description will be given.

The normal mode is a mode in which the current value is measured in a short cycle (for example, a cycle of several hundred msec to several seconds) by operating the BMS 30 at a predetermined clock frequency. A short cycle is an example of a predetermined cycle. In the normal mode, the current value is measured in a short cycle, so the SOC can be estimated accurately. As a result, the battery cell 21 can be appropriately managed.

The sleep mode is a mode in which the voltage drop of the battery cell 21 is suppressed by lowering the clock frequency of the BMS 30 than the normal mode. In the sleep mode, the clock frequency of the BMS 30 is low, so that the cycle for measuring the current value is longer than in the normal mode (for example, a cycle of several tens of seconds). Therefore, the power consumption of the battery cell 21 by the BMS 30 is suppressed. In other words, the voltage drop of the battery cell 21 is suppressed.

The deep sleep mode is a mode in which the relay 35 is turned off to cut off the current flow from the battery 1 to the vehicle 2, and the BMS 30 is stopped to further suppress power consumption as compared with the sleep mode.

Since the battery 1 is charged by the alternator when the engine of the vehicle 2 is operating, the power consumed by the BMS 30 does not matter. Therefore, the management unit 31 operates the BMS 30 in the normal mode in order to appropriately manage the battery cell 21 when the engine of the vehicle 2 is operating.

When the engine of the vehicle 2 is stopped, the battery cell 21 is not charged. Therefore, when the engine of the vehicle 2 is stopped (an example of the first predetermined condition), the management unit 31 puts the BMS 30 into sleep mode in order to suppress the power consumption by the BMS 30. To migrate to. In other words, the management unit 31 operates the BMS 30 in the sleep mode. Specifically, for example, when the management unit 31 receives a lock signal from the ECU of the vehicle 2 during the normal mode, it determines that the engine is stopped and shifts the BMS 30 to the sleep mode.

When the management unit 31 shifts to the sleep mode, it measures the voltage value in addition to the current value. Then, when a voltage value equal to or lower than a predetermined voltage value (for example, 2.5 V) higher than the non-reusable voltage value is measured, the management unit 31 deepens the BMS 30 in order to extend the period until the non-reusable voltage value is reached. Move to sleep mode. The predetermined voltage value is an example of the fourth reference value.

In FIG. 6, the dotted line 46 shows the change in voltage when the relay 35 is opened in the deep sleep mode but not stopped for the BMS 30 as a comparative example. In the present embodiment, since the BMS 30 is also stopped during the deep sleep mode, the period until the non-reusable voltage value is reached can be extended as compared with the comparative example.

However, even in this embodiment, the voltage drop of the battery cell 21 cannot be completely suppressed, and the voltage drops, albeit more slowly, than in the comparative example. Therefore, if the vehicle 2 is parked for a long period of time, the battery cell 21 may drop to a non-reusable voltage value, and the engine may not be able to start.

The transition from the sleep mode to the normal mode and the transition from the deep sleep mode to the normal mode will be described with reference to FIG. 7.
First, the transition from the sleep mode to the normal mode will be described. There are multiple triggers for shifting from the sleep mode to the normal mode, but here, the following two triggers will be described.

The first opportunity is when the management unit 31 receives the engine start signal from the ECU of the vehicle 2 via the communication unit 31D. When starting the engine, the ECU of the vehicle 2 transmits an engine start signal to the battery 1 before starting the start of the engine. Upon receiving the engine start signal, the management unit 31 immediately shifts the BMS 30 to the normal mode. That is, the first opportunity is when the start of the engine is confirmed.

Since the management unit 31 shifts the BMS 30 to the normal mode immediately after receiving the engine start signal, the BMS 30 can measure the current value of the current flowing from the battery 1 to the starter at a short cycle when the engine is started. As a result, the current value of the current flowing when the engine is started can be accurately reflected in the SOC.

The second trigger is when the SOC changes significantly in a short time during the sleep mode. Since power is supplied from the battery 1 to the vehicle-mounted device while the engine is stopped (in other words, during the sleep mode), the SOC of the battery cell 21 changes significantly in a short time depending on the power usage status of the vehicle-mounted device. If the SOC changes significantly in a short period of time, if the current value measurement cycle is long, the SOC is already abnormal the next time it is measured, even if there is no abnormality (for example, overdischarge) in the SOC when this time is measured. It can happen that you are in a state.

Therefore, when the SOC changes significantly in a short time during the sleep mode, the management unit 31 shifts the BMS 30 to the normal mode even when the engine is stopped in order to properly manage the battery cell 21. .. That is, the second opportunity is when the SOC changes significantly in a short time even if the start of the engine is not confirmed.

Whether or not the SOC changes significantly in a short time can be determined from the current value measured by the current sensor 32. Specifically, since the SOC is estimated from the integrated value of the current value, the current value measured at a certain time point is proportional to the amount of change in the SOC per unit time (hereinafter referred to as the amount of change in SOC) at that time point.
Therefore, when the management unit 31 measures a current value equal to or higher than a predetermined current value (an example of the first reference value) during the sleep mode (an example of the second predetermined condition), the SOC becomes large in a short time. It is determined that the BMS 30 has changed, and the BMS 30 is shifted to the normal mode. The predetermined current value is, for example, 100 mA. The current value of the current flowing from the battery 1 to the starter when the engine is started is, for example, 300 A, and 100 mA is a value smaller than the current value of the current flowing when the engine is started.

Whether or not the SOC changes significantly in a short period of time can be directly determined from the SOC. For example, the amount of SOC change per unit time (SOC change amount per unit time) by dividing the absolute value | ΔSOC | of the difference between the SOC estimated when the previous current value was measured and the SOC estimated when the current value was measured this time by the measurement cycle. An example of the amount of change in the state per unit time) is calculated, and when the calculated amount of change in SOC is greater than or equal to a predetermined reference value (an example of a third reference value) (an example of a second predetermined condition), the SOC is short. It may be judged that the time has changed significantly.

The transition from the deep sleep mode to the normal mode will be described. As described above, since the BMS 30 is stopped in the deep sleep mode, the management unit 31 cannot determine the timing of shifting to the normal mode by itself. Therefore, the management unit 31 shifts the BMS 30 to the normal mode when the driver (or mechanic) of the vehicle 2 connects the charger to the battery 1.

Specifically, since the relay 35 is open when the BMS 30 is in the deep sleep mode, the starter of the vehicle 2 does not rotate even if the driver tries to start the engine. Therefore, the driver determines that the battery is dead and connects an external charger to the battery 1. When the charger is connected to the battery 1, a starting voltage is applied from the interrupt circuit 31E to the CPU 31A, the management unit 31 is started, and the operation is restarted.

When the operation is resumed, the management unit 31 shifts the BMS 30 to the normal mode. However, as described above, if the parking period of the vehicle 2 is long, the voltage of the battery cell 21 may drop to less than the non-reusable voltage value. Since it is not desirable to close the relay 35 in a state where the voltage drops below the non-reusable voltage value, the management unit 31 does not close the relay 35 yet at this point.

When the management unit 31 shifts to the normal mode, the voltage sensor 33 measures the voltage value. Then, the management unit 31 determines whether or not the measured voltage value is equal to or higher than the non-reusable voltage value, and closes the relay 35 if the measured voltage value is equal to or higher than the non-reusable voltage value. On the other hand, if the voltage value is less than the non-reusable voltage value, the management unit 31 does not close the relay 35. This prevents the battery 1 from being reused.

(5) Effect of the Embodiment According to the BMS 30 according to the first embodiment, since the operation is performed in the sleep mode when the first predetermined condition is satisfied, the power consumption of the battery cell 21 by the BMS 30 can be suppressed. Then, when the second predetermined condition is satisfied during the sleep mode, the mode shifts to the normal mode even if the first predetermined condition is satisfied, so that the battery cell 21 can be appropriately managed. Therefore, according to the BMS 30, the battery cell 21 can be appropriately managed while suppressing the power consumption of the battery cell 21.

According to the BMS 30, the first predetermined condition is that the engine of the vehicle is stopped. That is, according to the BMS 30, when the engine of the vehicle is stopped, the sleep mode is entered, so that the power consumption of the battery cell 21 can be suppressed.

According to the BMS 30, the physical quantity is a current value, and the second predetermined condition is that the current sensor 32 measures a current value equal to or higher than the first reference value. When the second predetermined condition is satisfied, it is determined that the SOC has changed significantly in a short time, and the battery cell 21 can be appropriately managed by shifting to the normal mode. Since the current value is highly related to the state of the battery cell 21, such as being used for estimating the SOC of the battery cell 21, the battery cell 21 can be appropriately managed by using the current value as a physical quantity.

According to the BMS 30, the second predetermined condition is that the amount of change in SOC per unit time is equal to or greater than the third reference value. When the second predetermined condition is satisfied, it is determined that the SOC has changed significantly in a short time, and the battery cell 21 can be appropriately managed by shifting to the normal mode.

According to the BMS 30, the transition from the sleep mode to the normal mode is determined by the current value, and the transition from the sleep mode to the deep sleep mode is determined by the voltage value. That is, the physical quantity used for judgment differs between the transition from the sleep mode to the normal mode and the transition to the deep sleep mode. As a result, it is possible to appropriately determine whether or not to shift the operation mode according to the operation mode of the migration destination.

According to the BMS 30, when the charger is connected to the battery 1 during the deep sleep mode, the mode shifts to the normal mode. When the BMS 30 is in the deep sleep mode, the relay 35 is open and the engine cannot be started. In that case, for example, it is conceivable that the BMS 30 is provided with a switch for closing the relay 35, and the driver operates the switch to close the relay 35. However, not all drivers know that the switch should be operated, and a driver who does not know this may not be able to start the engine and may be confused. On the other hand, many drivers know that the charger should be connected when the battery is dead, so the possibility of starting the engine is higher than when operating the switch.

<Embodiment 2>
In the first embodiment described above, as the second predetermined condition, it has been described as an example that the current value equal to or higher than the reference value is measured by the current sensor 32 and the SOC change amount per unit time is equal to or higher than the reference value. .. On the other hand, the second predetermined condition may be that an abnormality in the battery cell 21 is detected.

Here, a temperature abnormality of the battery 1 will be described as an example. As described above, the battery 1 is provided with a temperature sensor 34 that measures the temperature of the battery cell 21. The BMS 30 measures the temperature by the temperature sensor 34 at a cycle corresponding to the normal mode or the sleep mode, and if a temperature equal to or higher than a predetermined reference temperature is measured, it is determined that the temperature is abnormal. As a result, a temperature abnormality is detected.
However, since the temperature sensor 34 also has a measurement error, it may be misjudged if it is determined that the temperature is abnormal immediately after detecting a temperature equal to or higher than the reference temperature once. Therefore, it is desirable to determine that the temperature is abnormal when a temperature above the reference temperature is detected multiple times.

However, since the cycle for measuring the temperature is longer in the sleep mode than in the normal mode, it takes time for the temperature to be measured a plurality of times, and there is a possibility that the response will be delayed if the temperature is actually abnormal. Therefore, when a temperature higher than the reference temperature is measured during the sleep mode, it is desirable to shift to the normal mode in order to measure the next temperature as soon as possible.

Therefore, when the temperature equal to or higher than the reference temperature is measured during the sleep mode, the management unit 31 according to the second embodiment shifts the BMS 30 to the normal mode even when the engine is stopped. Therefore, the next temperature can be measured at an early stage, and whether or not the temperature is abnormal can be determined at an early stage. As a result, it is possible to deal with temperature abnormalities at an early stage.

<Embodiment 3>
In the above-described first and second embodiments, a battery mounted on an engine vehicle and used for starting an engine and supplying electric power to an in-vehicle device has been described as an example. On the other hand, the battery according to the third embodiment is a battery for an auxiliary machine used for starting a drive battery mounted on a hybrid vehicle and supplying electric power to an in-vehicle device (here, referred to as an auxiliary machine).

Generally, a hybrid vehicle is equipped with a drive battery and an auxiliary battery that supply electric power to an electric motor that generates vehicle driving force. The drive battery is started by the electric power supplied from the auxiliary battery, and the electric motor is supplied with the electric power by the started drive battery.

The management unit 31 of the BMS 30 included in the auxiliary battery operates the BMS 30 in the sleep mode when the engine of the hybrid vehicle is stopped (an example of the first predetermined condition). Since the hybrid vehicle may be driven by an electric motor, the management unit 31 according to the third embodiment operates the BMS 30 in the sleep mode if the engine is stopped even when the vehicle is running.

Then, when the second predetermined condition is satisfied during the sleep mode, the management unit 31 shifts the BMS 30 to the normal mode even if the engine is stopped. Since the second predetermined condition is the same as that of the first embodiment and the second embodiment, the description thereof will be omitted.

According to the BMS 30 according to the third embodiment, the battery cell 21 can be appropriately managed while suppressing the power consumption of the battery cell 21 included in the auxiliary battery.

<Other embodiments>
The techniques disclosed herein are not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included in the technical scope disclosed herein.

(1) Although the current value has been described as an example of the physical quantity in the first embodiment, the physical quantity is not limited to the current value.
For example, the physical quantity may be the voltage value of the battery cell 21. Specifically, for example, if the voltage value is equal to or less than a predetermined lower limit voltage value, it is considered to be over-discharge (an example of abnormality). In this case, if the voltage drops to a predetermined voltage value higher than the lower limit voltage value (an example of the second reference value), even if the overdischarge is not yet reached, even if the overdischarge is foreseen and the mode shifts to the normal mode. good.

The physical quantity may be the temperature of the battery cell 21. For example, if the temperature is equal to or higher than a predetermined reference temperature (an example of the first reference value), it is assumed that the temperature is abnormal. In this case, when the temperature rises to a predetermined temperature lower than the reference temperature, the temperature may be shifted to the normal mode as the temperature abnormality is foreseen even if the temperature abnormality has not yet occurred.

(2) In the first embodiment, if the amount of change in SOC per unit time is equal to or greater than the reference value, the case of shifting to the normal mode has been described as an example, but whether or not to shift to the normal mode is determined from the SOC itself. May be good. For example, if the SOC is less than a predetermined lower limit value, it is assumed to be over-discharged. In this case, if the SOC drops to a predetermined SOC higher than the lower limit, the mode may be shifted to the normal mode assuming that the overdischarge is foreseen even if the overdischarge has not yet been reached.

(3) Although SOC has been described as an example of the state of the battery cell 21 in the first embodiment, the state of the battery cell 21 is not limited to this.
For example, the state of the battery cell 21 may be a voltage. Specifically, for example, the management unit 31 calculates and calculates the amount of voltage change per unit time by dividing the absolute value of the difference between the voltage value measured last time and the voltage value measured this time by the measurement cycle. If the amount of voltage change is equal to or greater than the reference value, it may be determined that the state of the battery cell 21 has changed significantly in a short time.

Further, the state of the battery cell 21 may be the temperature. Specifically, for example, the management unit 31 calculates the amount of temperature change per unit time by dividing the absolute value of the difference between the temperature measured last time and the temperature measured this time by the measurement cycle, and the calculated temperature change. If the amount is equal to or greater than the reference value, it may be determined that the state has changed significantly in a short period of time.

The state of the battery cell 21 may be the temperature of the entire battery 1 estimated from the local temperature measured by the temperature sensor 34. Specifically, for example, data representing the relationship between the local temperature measured by the temperature sensor 34 and the temperature of the entire battery 1 is stored in the ROM 31B, and the management unit 31 stores the battery 1 corresponding to the local temperature. The temperature of the entire battery 1 may be estimated by specifying the overall temperature from the data. Then, the management unit 31 determines the amount of change in the temperature of the entire battery 1 per unit time during the sleep mode, and if the amount of change is equal to or greater than the reference value, the state of the battery cell 21 is significantly changed in a short time. You may judge.

The state of the battery cell 21 may be SOH (State Of Charge). SOH may be used in two ways. One is the capacity retention rate. The capacity retention rate indicates the ratio of the charge capacity at a certain point in time to the initial charge capacity of the battery cell 21, and becomes smaller as the battery cell 21 deteriorates. Therefore, if the capacity retention rate drops significantly in a short time during the sleep mode, the mode may be shifted to the normal mode. The other is the rate of increase in resistance. The resistance increase rate indicates the ratio of the resistance value at a certain time point to the initial resistance value of the battery cell 21, and increases as the battery cell 21 deteriorates. Therefore, if the resistance increase rate greatly increases in a short time during the sleep mode, the normal mode may be entered.

(4) In the second embodiment, the temperature abnormality is described as an example of the abnormality of the battery cell 21, but the abnormality is not limited to the abnormal temperature. For example, the abnormality may be an over-discharge of the battery cell 21. Specifically, for example, when a voltage value equal to or lower than a predetermined lower limit voltage value is measured, it may be determined to be over-discharged and the mode may be shifted to the normal mode. Alternatively, when the SOC estimated from the current value or the voltage value becomes equal to or less than a predetermined lower limit value, it may be determined as over-discharge and the mode may be shifted to the normal mode.

(5) In the above embodiment, the battery for starting the engine mounted on the engine vehicle and the battery for the auxiliary machine mounted on the hybrid vehicle have been described as an example, but the battery is used as a backup battery mounted on these vehicles 2. It may be a battery.

(6) In the above embodiment, a battery mounted on a vehicle such as an engine vehicle or a hybrid vehicle has been described as an example, but the battery may be used for a device other than the vehicle as long as it is a device having a power source. ..
For example, the battery may be one used in construction machinery. The battery may be used in a fixed power storage system installed in a home or business. Specifically, some fixed power storage systems are equipped with an engine for charging the battery cell 21. The battery may be one used in such a power storage system.

(7) In the above embodiment, the case where the management unit 31 has one CPU has been described as an example, but the management unit 31 has a configuration including a plurality of CPUs, an ASIC (Application Specific Integrated Circuit), and an FPGA (Field). -A configuration including a hard circuit such as a Programmable Gate Array) or a configuration including both a hard circuit and a CPU may be used.

21 ... Battery cell (example of power storage element), 30 ... Battery management device (example of management device), 31 ... Management unit, 31E ... Interrupt circuit (example of voltage application unit), 32 ... Current sensor (example of measurement unit) , 33 ... Voltage sensor (example of measurement unit), 34 ... Temperature sensor (example of measurement unit)

Claims (7)

It is a management device for power storage elements used for starting a power source and supplying electric power to equipment.
A measuring unit that measures physical quantities related to the state of the power storage element, and
A management unit that manages the power storage element and
Equipped with
The management device has a first mode in which the physical quantity is measured by the measuring unit in a predetermined cycle, and a second mode in which the physical quantity is measured in a cycle longer than the predetermined cycle.
When the first predetermined condition regarding the power source is satisfied, the management unit operates the management device in the second mode, and when the second predetermined condition regarding the power storage element is satisfied during the second mode. Moves the management device to the first mode even if the first predetermined condition is satisfied.
The second predetermined condition is a management device for a power storage element, in which an overdischarge of the power storage element is foreseen . The management device for a power storage element according to claim 1.
The first predetermined condition is that the power source is stopped, which is a management device for a power storage element. The management device for a power storage element according to claim 1 or 2.
The physical quantity includes the voltage value of the power storage element, and includes the voltage value.
When the voltage of the power storage element drops to a predetermined voltage value higher than the predetermined lower limit voltage value during the second mode, the management unit determines that over-discharge of the power storage element is predicted, and manages the power storage element. Device. The management device for a power storage element according to claim 1 or 2.
The physical quantity includes the current value of the current flowing through the power storage element.
The management unit estimates the charging state of the power storage element based on the current value measured by the measuring unit, and when the charging state drops to a predetermined charging state higher than a predetermined lower limit value during the second mode. , A management device for a power storage element that determines that an overdischarge of the power storage element has been foreseen. The management device for a power storage element according to any one of claims 1 to 4 .
The management device includes a circuit breaker connected in series with the power storage element, and has a third mode in which the circuit breaker is opened to cut off the current.
The physical quantity includes the voltage value of the power storage element, and includes the voltage value .
The management unit is a storage element management device that shifts the management device to the third mode when a voltage value equal to or lower than the fourth reference value is measured by the measurement unit during the second mode. The management device for a power storage element according to claim 5 .
The management unit is a storage element management device that shifts the management device to the first mode when a charger is connected to the power storage element during the third mode. It is a method of managing a power storage element using a power storage element management device used for starting a power source and supplying electric power to a device.
The management device has a first mode for measuring a physical quantity related to the state of the power storage element in a predetermined cycle, and a second mode for measuring the physical quantity in a cycle longer than the predetermined cycle.
The management method is
The first step of operating the management device in the second mode when the first predetermined condition regarding the power source is satisfied, and
When the second predetermined condition regarding the power storage element is satisfied during the second mode, the second step of shifting the management device to the first mode even if the first predetermined condition is satisfied. ,
Including
The second predetermined condition is a method for managing a power storage element, wherein an overdischarge of the power storage element is foreseen .

Images