JP5938633B2 - Battery chargeability determination device - Google Patents

Description

  The present invention relates to a battery chargeability determination device.

  EV (Electric Vehicle) and PHEV (Plug-in Hybrid Electric Vehicle) require charging work every two to three months when the vehicle is stored for a long period of time. In addition, in order to prevent the driving battery from becoming lower than the lower limit of use voltage due to self-discharge caused by leaving the vehicle for a long time or current flowing through the battery sensor, Vehicles are also prohibited.

JP 2007-228703 A JP 2009-254215 A JP 2006-340451 A

  When the voltage of the driving battery falls below the lower limit voltage due to overdischarge, in the worst case, even if it is charged, the battery function does not return, and as a result, the system does not start and the vehicle cannot be used. In many cases, however, the battery is often overcharged and can be charged without any problems even when the voltage drops below the lower limit of use voltage. Therefore, it is desired to accurately determine whether or not the overcharged driving battery can be recharged.

  The present invention has been made in view of the above problems, and an object thereof is to provide a battery chargeability determination device that determines whether or not a battery in an overdischarged state can be charged.

A battery chargeability determination device according to a first aspect of the present invention that solves the above problem is provided.
Voltage measuring means for measuring the voltage of the driving battery mounted on the electric vehicle;
Control means for controlling charging and discharging of the battery;
Determining means for determining whether or not the battery can be charged based on the displacement of the voltage measured by the voltage measuring means;
The control means, when the voltage of the battery is equal to or lower than the use lower limit voltage defined for the battery,
A charge check that measures the voltage displacement of the battery while charging the battery using a predetermined charge current value or a predetermined charge power value, and a predetermined discharge current value or a predetermined discharge power after the charge check. While discharging from the battery using a value, repeatedly with a discharge check that measures displacement of the voltage of the battery alternately several times,
The determination means includes
Whether or not the battery can be charged is determined based on a change in voltage of the battery in each of the charge check and the discharge check.

A battery chargeability determination device according to a second aspect of the present invention for solving the above-described problem is provided.
In the battery chargeability determination device according to the first invention,
The control means includes
The predetermined charging current value and the predetermined discharging current value, or the predetermined charging power value and the predetermined discharging power value are sequentially increased every time the charging check and the discharging check are repeated. .

An apparatus for determining whether or not a battery can be charged according to a third aspect of the present invention for solving the above problem is provided.
In the battery chargeability determination device according to the second invention,
A plurality of the batteries are mounted on the electric vehicle,
The determination means includes
When there is a battery in which the displacement of the battery voltage in each of the charge check and the discharge check is equal to or higher than a first determination value for determining abnormality, it is determined that charging is not possible,
The first determination value is
Each time the charge check and the discharge check are repeated, the value is sequentially set larger.

A battery chargeability determination device according to a fourth aspect of the present invention for solving the above-described problem is provided.
In the battery chargeability determination device according to the third invention,
The first determination value is
When the charge check and the discharge check are performed using the predetermined charge power value and the predetermined discharge power value, they are set smaller than when the predetermined charge current value and the predetermined discharge current value are used. It is characterized by.

A battery chargeability determination device according to a fifth aspect of the present invention for solving the above-described problem is provided.
In the battery chargeability determination device according to any one of the first to fourth inventions,
The control means includes
Using the device mounted on the vehicle, the battery current or power during the discharge check is consumed.

A battery chargeability determination device according to a sixth aspect of the present invention for solving the above-described problem is provided.
In the battery chargeability determination device according to the fifth aspect,
The control means includes
Using the current or electric power of the battery at the time of the discharge check, the operation of the device mounted on the vehicle is confirmed.

A battery chargeability determination device according to a seventh aspect of the present invention that solves the above problem is provided.
In the battery chargeability determination device according to any one of the first to sixth inventions,
The control means includes
After the charge check and after the discharge check, providing a rest time that becomes a stable time of the open circuit voltage of the battery, measuring the displacement of the battery voltage in the rest time,
The determination means includes
Whether or not the battery can be charged is determined based on a change in voltage of the battery during the pause time.

An apparatus for determining whether or not a battery can be charged according to an eighth aspect of the invention for solving the above-described problem is provided.
In the battery chargeability determination device according to the seventh invention,
The determination means includes
When there is a battery in which the displacement of the battery voltage during the pause time is equal to or higher than a second determination value for determining abnormality, it is determined that charging is not possible,
The second determination value is
Each time the charge check and the discharge check are repeated, the value is sequentially set larger.

  According to the first invention, since the charge check and the discharge check are repeatedly performed a plurality of times, even if the battery is susceptible to the environmental temperature of the battery and the deterioration variation for each battery (cell), the chargeability is accurately determined. Judgment can be made.

  According to the second invention, each time the charge check and the discharge check are repeated, the current value or the power value of the charge and discharge is sequentially increased, so that the load on the battery can be reduced.

  According to the third and eighth inventions, the determination value is increased in accordance with the current value or the power value of the charge and discharge that sequentially increase each time the charge check and the discharge check are repeated. Can do.

  According to the fourth invention, when the power value is used for the charge check and the discharge check, the determination value is made smaller than when the current value is used. Can do.

  According to the fifth aspect of the invention, since the battery current or power at the time of the discharge check is consumed using the device mounted on the vehicle, the discharge can be performed efficiently.

  According to the sixth aspect of the invention, since the operation check of the device mounted on the vehicle is performed using the battery current or power during the discharge check, the device operation check can be performed efficiently.

  According to the seventh aspect, after the charge check and after the discharge check, a pause time is provided as a stable time for the open circuit voltage of the battery, and the battery voltage displacement during the pause time is measured to determine whether or not the battery can be charged. Therefore, when the voltage drop during the downtime is excessive, it can be determined that the battery is affected by a fine short-circuit or foreign matter, and it is possible to accurately determine whether charging is possible.

It is a schematic block diagram which shows an example of embodiment of the rechargeability judgment apparatus of the battery which concerns on this invention. FIG. 3 is a flowchart showing a determination procedure performed by the battery recharge permission determination device shown in FIG. 1, and mainly describes a procedure at the first level. FIG. FIG. 3 is a flowchart illustrating a determination procedure performed by the battery recharge permission determination device illustrated in FIG. 1, and mainly describes the procedures at the second and third levels. FIG. 3 is a flowchart illustrating a determination procedure performed by the battery recharge permission determination device illustrated in FIG. 1, and mainly describes a complete discharge and charge procedure after the first to third level procedures. It is the schematic explaining the working voltage of a battery. It is a map which shows the maximum electric current value with respect to battery temperature. It is a map which shows the charging time, rest time, and judgment value in each level, discharge time, rest time, and judgment value. It is a map which shows the combination of the apparatus of the discharge side in each level. It is a map which shows the correction coefficient based on battery temperature and a capacity | capacitance maintenance factor. It is a graph which shows the voltage displacement with respect to charge time in a 1st level, (a) is normal time, (b) shows the time of abnormality. It is a graph which shows the voltage displacement with respect to rest time in a 1st level, (a) is normal time, (b) shows the time of abnormality. It is a graph which shows the voltage displacement with respect to discharge time in a 1st level, (a) is normal time, (b) shows the time of abnormality. It is a graph which shows the voltage displacement with respect to charge time in a 2nd, 3rd level, (a) is normal time, (b) shows the time of abnormality. It is a graph which shows the voltage displacement with respect to a rest time in a 2nd, 3rd level, (a) is normal time, (b) shows the time of abnormality. It is a graph which shows the voltage displacement with respect to discharge time in a 2nd, 3rd level, (a) is normal time, (b) shows the time of abnormality.

  Hereinafter, with reference to FIGS. 1-15, embodiment of the rechargeability judgment apparatus of the battery which concerns on this invention is described. Here, EV (electric vehicle) is described as an example, but the present invention is applicable to an electric vehicle including PHEV.

Example 1
FIG. 1 is a schematic configuration diagram illustrating a battery rechargeability determination apparatus according to the present embodiment. First, a vehicle having the battery rechargeability determination device of this embodiment will be described. Note that “Fr” in FIG. 1 indicates the vehicle front direction.

  In this embodiment, the vehicle 10 is an EV, and includes a motor 11 serving as a power source, and a transmission 13 that transmits power from the motor 11 to the drive shaft 12, and a drive wheel attached to the drive shaft 12. 14 is driven to drive the vehicle 10. Electricity is supplied to the motor 11 from a battery unit 20 mounted on the vehicle 10 via an inverter 15 that performs electric DC / AC conversion, and the motor 11 is rotationally driven by the supplied electricity.

  The battery unit 20 includes a plurality of battery modules 21 including a plurality of cells (batteries), and each cell monitor unit (voltage measuring means) 22 performs battery temperature, battery voltage, etc. of each cell of each battery module 21. Is being monitored. Each cell monitor unit 22 is connected to a BMU (Battery Management Unit; control means, battery control means) 24 via a communication line 23 (for example, CAN (Controller Area Network)), and this BMU 24 is a battery unit. 20 charge / discharge control, for example, control of current value and power value during charging and discharging.

  In order to charge the battery unit 20, the vehicle 10 is provided with a quick charge connector 25 and a normal charge connector 26. When the power cable from the quick charger is connected to the quick charge connector 25, the three-phase 200V is converted into direct current by the quick charger and supplied to the battery unit 20 to charge each battery module 21 of the battery unit 20 in a short time. Like to do. Further, when a power cable from a household outlet is connected to the ordinary charging connector 26, AC 200V or 100V is converted into DC by the in-vehicle charger 27 and supplied to the battery unit 20 to each battery module 21 of the battery unit 20. I try to charge it.

  The DC power supplied from the battery unit 20 is mainly used by the motor 11 and the inverter 15, but is also used by the heater 31 and the air conditioner 32 (air conditioner compressor). In addition, a DC / DC converter 33 is provided together with the on-vehicle charger 27. The DC / DC converter 33 converts a high DC voltage supplied from the battery unit 20 into a low voltage, and a battery for an auxiliary machine 12V. (Not shown) is supplied for charging. The auxiliary battery 12V battery is connected to each device of the vehicle 10, for example, the brake negative piezoelectric pump 34 and the like. The brake negative piezoelectric pump 34 and the like are supplied with electric power supplied from the auxiliary battery 12V. It is operating.

  These devices are directly or indirectly controlled by an integrated ECU (Electronics Control Unit; control means, determination means) 35. For example, the brake negative piezoelectric pump 34 is directly controlled by the integrated ECU 35, and the heater 31 is indirectly controlled by the integrated ECU 35 via the communication line 36 (for example, CAN) and the heater ECU 37, The air conditioner 32 is also indirectly controlled by the integrated ECU 35 via the communication line 36 and the air conditioner ECU 38.

  The inverter 15, the on-vehicle charger 27, the DC / DC converter 33, and the like are indirectly controlled by the integrated ECU 35 via the communication line 36, and the battery unit 20 is connected via the communication line 36 and the BMU 24. It is indirectly controlled by the integrated ECU 35. For example, when there is an abnormality in the battery unit 20, the integrated ECU 35 displays an abnormality on the combination panel 39.

  In the above configuration, the integrated ECU 35 uses the BMU 24 and the cell monitor unit 22 to determine whether each cell of each battery module 21 can be recharged according to the following procedure.

  Next, the flowcharts shown in FIGS. 2 to 4 will be described with reference to FIGS. 5 to 15 together with FIG. 1 described above.

  Here, FIGS. 2 to 4 are flowcharts showing a determination procedure performed by the battery rechargeability determination device shown in FIG. 1, and FIG. 2 mainly explains the procedure at the first level. FIG. 3 mainly explains the procedure at the second and third levels, and FIG. 4 mainly shows the procedure of complete discharge and charging after the procedures at the first to third levels. Explain. FIG. 5 is a schematic diagram for explaining the operating voltage of the battery, FIG. 6 is a map showing the maximum current value with respect to the battery temperature, and FIG. 7 shows the charging time, the rest time and the judgment value at each level, FIG. 8 is a map showing a combination of devices on the discharge side at each level, and FIG. 9 is a map showing a correction coefficient based on the battery temperature and the capacity maintenance rate. It is.

  10 to 12 are graphs showing the voltage displacement at the first level, FIG. 10A is a graph when the voltage displacement with respect to the charging time is normal, and FIG. 10B is the graph with respect to the charging time. FIG. 11A is a graph when the voltage displacement is abnormal, FIG. 11A is a graph when the voltage displacement with respect to the pause time is normal, FIG. 11B is a graph when the voltage displacement with respect to the pause time is abnormal, and FIG. FIG. 12A is a graph when the voltage displacement with respect to the discharge time is normal, and FIG. 12B is a graph when the voltage displacement with respect to the discharge time is abnormal. 13 to 15 are graphs showing the voltage displacement at the second and third levels, FIG. 13A is a graph when the voltage displacement with respect to the charging time is normal, and FIG. 14A is a graph when the voltage displacement with respect to the charging time is abnormal, FIG. 14A is a graph when the voltage displacement with respect to the pause time is normal, and FIG. 14B is a graph when the voltage displacement with respect to the pause time is abnormal, FIG. 15A is a graph when the voltage displacement with respect to the discharge time is normal, and FIG. 15B is a graph when the voltage displacement with respect to the discharge time is abnormal. 10 to 15 exemplify the voltage displacement of three cells instead of all the cells in order to make the graph easy to see.

(Step S1)
The power cable is connected to the quick charge connector 25 or the normal charge connector 26 (plug-in). The determination procedure described later can be performed regardless of whether the power cable is connected to either the quick charge connector 25 or the normal charge connector 26.

(Step S2)
The battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22.

(Step S3)
It is checked whether the detected battery voltage is equal to or lower than the use lower limit voltage. If it is not less than the use lower limit voltage, the process proceeds to step S4. As shown in FIG. 5, the battery module 21 has a use lower limit voltage and a use upper limit voltage that prescribe the use voltage range in advance, and the battery voltage is not lower than the use lower limit voltage. If it is within, the process proceeds to step S4, and if it is equal to or lower than the use lower limit voltage, that is, if it is out of the use voltage range, the process proceeds to step S5 to determine whether recharge is possible as described later.

(Step S4)
If the battery voltage is not less than or equal to the use lower limit voltage, that is, within the use voltage range, the process proceeds to step S4, and if normal power control, for example, the power cable is connected to the quick charge connector 25, rapid When charging is performed and a power cable is connected to the normal charging connector 26, charging from a household power source is performed.

(Step S5)
If the battery voltage is equal to or lower than the use lower limit voltage, that is, if it is in an overdischarged state, the battery temperature of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22.

(Step S6)
Based on the detected battery temperature, the maximum current value at the maximum level is determined, and then the current values used for charging and discharging at a plurality of levels are determined. For example, the maximum current value of the maximum level is determined based on a map showing the maximum current value with respect to the battery temperature shown in FIG. Specifically, when the battery temperature is lower than −25 ° C. (column −35 in FIG. 6), the maximum current value of charging at the maximum level is determined as i _C1 [A], and the battery temperature is −25 to 35. In the case of ° C. (the column of −25 to 35 in FIG. 6), the maximum current value of charging at the maximum level is determined as i _C2 [A] (hereinafter, the maximum current value of charging at the maximum level is collectively referred to as i _C. ). Further, the maximum current value of the discharge at the maximum level is determined as i _D [A]. In FIG. 6, as the battery temperature decreases, the internal resistance value of the battery increases, so the maximum current value for charging is set smaller (i _C1 <i _C2 ). On the other hand, the maximum discharge current value is not affected by the battery temperature so much and is constant regardless of the battery temperature. A map showing the maximum current value with respect to the battery temperature as shown in FIG. 6 may be set as appropriate according to the type and capacity of the battery used.

  Thereafter, for example, when three levels are implemented as a plurality of levels, the current values used for charging and discharging at the first to third levels are determined as shown in Table 1 below.

  Here, Table 1 will be described. For example, when implementing three levels, based on the maximum current value at the maximum level, the current value at the third level is 1/1, the current value at the second level is 1/2, The current value shown in Table 1 is determined by setting the current value of the level to 1/4. The number of levels is preferably plural (two or more). In this case, the current value of the first level is the lowest, and the current value to be used is increased as shown in Table 1 as the level increases. Here, the constant current values shown in Table 1 are used at each level, but a constant power value (unit: W) may be used instead of the constant current value. Even in this case, as in Table 1, the power value at the first level is the lowest, and the power value to be used increases as the level increases.

As for the number of levels used for the charge / discharge check, it is desirable to perform the charge / discharge check at a plurality of levels for the following reasons.
(1) Although the battery has deteriorated due to long-term vehicle storage, the exact degree of deterioration cannot be read with only one level.
(2) The measurement data is greatly affected by the environmental temperature of the battery.
(3) There is variation in deterioration of single cells (cell arrangement position, individual difference, etc.).

  For the above reason, in the case of data of only one level, there is a possibility that the measurement has a great influence. Therefore, the accuracy of measurement data can be improved by implementing a plurality of levels.

(Step S7)
Next, 1 is set to the level number n.

(Step S8)
Whether the level number n is 2 or more is checked. If it is not 2 or more, that is, if n = 1, the process proceeds to step S9, and if it is 2 or more, the process proceeds to step S21.

(Step S9)
If the level number n is not 2 or more, n = 1, that is, the first level, and charging is performed using the constant charging current value i _C / 4 [A] of the first level as shown in Table 1. To start. For example, when the battery temperature is 10 ° C., charging is started at i _C1 / 4 [A].

(Step S10)
While detecting the battery voltage of each cell of each battery module 21 via the BMU 24 and the cell monitor unit 22, the battery voltage is equal to or higher than the lower limit voltage and charging for 10% of the capacity at the lower limit voltage is completed. Continue charging until However, if the battery voltage may reach the use upper limit voltage shown in FIG. 5, the charging is immediately stopped.

  Here, charging is continued until charging for 10% of the capacity at the use lower limit voltage is completed, but this starts current integration from the use lower limit voltage, and 10% of the capacity at the use lower limit voltage. If you charge the minute, it means to stop charging. In addition, here, the charging time is 10% of the capacity at the lower limit of use voltage, but this takes into account the charging capacity at which the subsequent charge / discharge check can be performed without problems, and the charging capacity according to the battery temperature. May be appropriately changed. Here, the charge capacity is determined in advance. However, in the subsequent charge / discharge check, the charge / discharge capacity is not determined in advance, but the charge / discharge time is determined in advance as shown in FIG. Yes.

(Step S11)
When the battery voltage is equal to or higher than the use lower limit voltage and charging for 10% of the capacity at the use lower limit voltage is completed, the battery voltage displacement of each cell of each battery module 21 is changed via the BMU 24 and the cell monitor unit 22. Detect and confirm whether there is any abnormality in the voltage displacement. If there is no abnormality, the process proceeds to step S12, and if there is an abnormality, the process proceeds to step S19. At this time, the determination value of the voltage displacement for determining the presence or absence of abnormality is determined using the determination value v _C1 [mV] based on, for example, the map shown in FIG.

  Here, FIG. 7 will be described. FIG. 7 defines the charging time / the rest time after charging and the discharging time / the rest time after discharging and the respective determination values at each level. The determination value is a voltage difference for determining abnormality in the charging time, discharging time, and resting time. If the variation in the battery voltage of each cell is within the range of the voltage difference, it is determined that there is no abnormality. . This determination value is appropriately set according to the battery temperature and the charge / discharge current value. In the case of a plurality of levels, the determination value of the first level is the lowest, and the determination value to be used is increased as the level increases. Note that both the determination value at the charge time and the determination value at the discharge time correspond to the first determination value, and both the determination value at the rest time after charging and the determination value at the rest time after discharge correspond to the second determination value. To do.

  The pause time is a stable time of OCV (open voltage), and is preferably as long as possible in order to completely stabilize the open voltage, but is set in consideration of time reduction. For example, the rest time after charging is set to a fixed time, and the rest time after charging is set longer than the rest time after discharging. This is because the lower the battery temperature and the higher the charging current value, the longer the OCV stabilization time. Therefore, in particular, it is desirable to appropriately change the pause time after charging in accordance with the battery temperature and the charging current value. Further, the rest time after discharge may be changed as appropriate in accordance with the battery temperature and the discharge current value.

  Here, the charge / discharge check is performed at a constant current value at each level. However, when the charge / discharge check is performed at a constant power value, the magnitude of the voltage displacement per unit time is constant. Since the current value is smaller than in the case of the current value, the determination value shown in FIG. 7 is also set to a value smaller than that in the case of a constant current value. In the case of a plurality of levels, as in the case of a constant current value, the determination value at the first level is the lowest and the determination value to be used is increased as the level increases.

  Then, with reference to FIGS. 10A and 10B, the determination of normality and abnormality of the voltage displacement due to the first level charging will be described.

When charging at the first level is started for each cell of the battery module 21 after overdischarge, if there is no abnormality in each cell of the battery module 21, as time passes, as shown in FIG. The battery voltage rises from the charging start voltage, and becomes a battery voltage that is equal to or higher than the lower limit voltage. Then, after the charging for 10% of the capacity at the use lower limit voltage is completed, the battery voltage of each cell falls within the range of the determination value (first level determination value v _C1 [mV]). In this way, it is only necessary that the battery voltages of all the cells rise uniformly.

On the other hand, when there is an abnormality in the cells of the battery module 21, as shown in FIG. 10B, the battery voltage increases from the charging start voltage with the passage of time, and the battery voltage is equal to or higher than the lower limit voltage. However, after charging for 10% of the capacity at the lower limit of use voltage is completed, the battery voltage of each cell does not fall within the range of the judgment value (first level judgment value v _C1 [mV]), The battery voltage varies, and it can be determined that there is an abnormality. In the case of such an abnormality, battery deterioration is significant due to long-term storage of the vehicle 10, the internal resistance is extremely high, and there is a possibility that charging is impossible. Therefore, it is determined that the battery module 21 cannot be reused.

  Here, normality / abnormality is determined based on the variation in battery voltage after the end of charging, but due to variation in battery voltage difference before and after charging, variation in displacement per unit time of battery voltage during charging, etc. Normal or abnormal may be determined.

(Step S12)
If there is no abnormality in the voltage displacement, stop charging.

(Step S13)
After the charging is stopped, a predetermined rest time (OCV stabilization time) is provided, and during the rest time, the battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22, and the predetermined rest time. It is confirmed whether there is no abnormality in the voltage displacement after the lapse of time. If there is no abnormality, the process proceeds to step S14, and if there is an abnormality, the process proceeds to step S19. At this time, for example, based on the map shown in FIG. 7, the predetermined pause time is the pause time t _CS1 [seconds], and the determination value is determined using the determination value v _C1 [mV].

  Here, with reference to FIG. 11 (a), (b), the normal / abnormal judgment is demonstrated about the voltage displacement by the rest after 1st level charge.

After completion of charging at the first level, when a predetermined pause time is provided and the voltage displacement of each cell of the battery module 21 is confirmed, if there is no abnormality in each cell of the battery module 21, FIG. As shown in a), even if time passes, the battery voltage of each cell does not change, and the battery voltage of each cell after the elapse of a predetermined pause time is determined as a determination value (first-level determination value v _C1 [MV]).

On the other hand, when the cell of the battery module 21 is abnormal, as shown in FIG. 11 (b), there is a cell in which the battery voltage decreases as time elapses, and each cell after a predetermined pause time elapses. The battery voltage does not fall within the range of the determination value (first-level determination value v _C1 [mV]), and the battery voltage varies, so that it can be determined as abnormal. In the case of such an abnormality, particularly when the voltage drop is excessive, it is considered that the cell is affected by a fine short circuit or a foreign substance.

  In this case as well, normality / abnormality is determined by the variation in battery voltage after the lapse of the quiescent time, but the variation in battery voltage difference before and after the quiescent time and the amount of displacement per unit time of the battery voltage during the quiescent time Normality or abnormality may be determined based on variations in the

(Step S14)
When there is no abnormality in the voltage displacement, as shown in Table 1, the discharge is started using the first level constant discharge current value i _D / 4 [A]. At this time, the discharge is performed by operating an in-vehicle device that generates an electrical load installed in the vehicle 10. For example, as shown in the combination map of FIG. 8, at the first level, the DC / DC converter 33 is operated to discharge i _D / 4 [A]. In order to increase the load on the DC / DC converter 33, a headlamp connected to the battery for the auxiliary machine 12V, the brake negative piezoelectric pump 34, etc. may be operated in combination. As described above, since the current is consumed by the in-vehicle device at the time of the discharge check, the discharge check can be performed easily and efficiently. Furthermore, as will be described in step S33, which will be described later, if the operation check of each device of the vehicle 10 is performed together, the efficiency is further improved.

(Step S15)
While detecting the battery voltage of each cell of each battery module 21 via the BMU 24 and the cell monitor unit 22, the discharge is continued until a predetermined discharge time elapses. At this time, the predetermined discharge time is, for example, discharge time t _D1 [seconds] based on the map shown in FIG.

(Step S16)
After elapse of a predetermined discharge time, the battery voltage displacement of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22 to check whether there is any abnormality in the voltage displacement. The process proceeds to S17, and if there is an abnormality, the process proceeds to Step S19. At this time, the determination value is determined using the determination value v _D1 [mV] based on, for example, the map shown in FIG.

  Here, with reference to FIGS. 12A and 12B, the normality / abnormality determination of the voltage displacement due to the first level discharge will be described.

When discharge at the first level is started in each cell of the battery module 21 after the suspension, when there is no abnormality in each cell of the battery module 21, as shown in FIG. Although the battery voltage decreases, even after a predetermined discharge time has elapsed, the battery voltage of each cell is a battery voltage that is equal to or higher than the use lower limit voltage, and a determination value (first-level determination value v). _D1 [mV]). In this way, it is only necessary that the battery voltages of all the cells are lowered uniformly.

On the other hand, when there is an abnormality in the cell of the battery module 21, the battery voltage decreases with the passage of time as shown in FIG. After a predetermined discharge time, the battery voltage of each cell is a battery voltage that is equal to or higher than the use lower limit voltage, but does not fall within the range of the judgment value (first level judgment value v _D1 [mV]), The battery voltage varies, and it can be determined that there is an abnormality.

  In this case as well, normality / abnormality is determined by the variation in battery voltage after the end of discharge, but due to variations in the battery voltage difference before and after the discharge, variations in the amount of displacement per unit time of the battery voltage during discharge, etc. Normal or abnormal may be determined.

(Step S17)
If there is no abnormality in the voltage displacement, the discharge is stopped.

(Step S18)
After the discharge is stopped, a predetermined rest time (OCV stabilization time) is provided again. During the rest time, the battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22, and the predetermined time. If there is no abnormality in the voltage displacement after elapse of the rest time, the process proceeds to step S20. If there is an abnormality, the process proceeds to step S19. At this time, for example, based on the map shown in FIG. 7, the predetermined pause time is the pause time t _DS1 [second], and the determination value is determined using the determination value v _D1 [mV]. The normal / abnormal determination here is the same as the above-described FIGS. 11A and 11B except for the pause time and the determination value. Therefore, the description is omitted here together with the illustration. .

(Step S19)
In the above-described steps S11, S13, S16, and S18, when it is determined that there is an abnormality, for example, the abnormality is displayed on the combination panel 39 or a warning sound is sounded to notify the driver of the battery abnormality. . Furthermore, even when it is determined that there is an abnormality in steps S23, S25, S28, and S30 described later, the battery abnormality is notified to the driver using the same method.

(Step S20)
1 is added to the level number n (n = n + 1), and the process returns to step S8. In step S8, it is confirmed whether the level number n is 2 or more. In this case, since n = 2, the process proceeds to step S21.

  In the following steps S21 to S30, the difference between n = 2, that is, the second level, and n = 3, that is, the third level is only the setting of time and determination value. Therefore, in steps S21 to S30, the third level will be described together with the second level.

(Step S21)
In the case of the second level, as shown in Table 1, charging is started using a constant charging current value i _C / 2 [A] of the second level. Further, in the case of the third level, as shown in Table 1, charging is started using a constant charging current value i _C [A] of the third level. For example, when the battery temperature is 10 ° C., in the second level i _C1 / 2 [A], in the third level to start charging in i _C1 [A].

(Step S22)
While detecting the battery voltage of each cell of each battery module 21 via the BMU 24 and the cell monitor unit 22, charging is continued until a predetermined charging time elapses. At this time, the predetermined charging time is, for example, charging time t _C2 [seconds] at the second level and charging time t _C3 [seconds] at the third level based on the map shown in FIG. However, if the battery voltage may reach the use upper limit voltage shown in FIG. 5, the charging is immediately stopped.

(Step S23)
After elapse of a predetermined charging time, the battery voltage displacement of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22 to check whether there is any abnormality in the voltage displacement. The process proceeds to S24, and if there is an abnormality, the process proceeds to Step S19. At this time, the determination value is determined using, for example, the determination value v _C2 [mV] at the second level and the determination value v _C3 [mV] at the third level based on the map shown in FIG.

  Here, with reference to FIGS. 13A and 13B, the determination of normality and abnormality of the voltage displacement due to the second level and third level charging will be described.

When each cell of the battery module 21 starts charging at the second level and the third level, if there is no abnormality in each cell of the battery module 21, as time passes, as shown in FIG. After the predetermined charging time elapses, the battery voltage of each cell is determined as a determination value (second level determination value v _C2 [mV] or third level determination value v _C3 [mV]). ).

On the other hand, when there is an abnormality in the cells of the battery module 21, as shown in FIG. 13 (b), the battery voltage increases as time elapses. Battery voltage does not fall within the range of the judgment value (the second level judgment value v _C2 [mV] or the third level judgment value v _C3 [mV]). Can be determined.

  In this case as well, normality / abnormality is determined based on variations in battery voltage after charging, but due to variations in battery voltage difference before and after charging, variations in battery voltage displacement during charging, etc. Normal or abnormal may be determined.

(Step S24)
If there is no abnormality in the voltage displacement, stop charging.

(Step S25)
After the charging is stopped, a predetermined rest time (OCV stabilization time) is provided, and during the rest time, the battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22, and the predetermined rest time. It is confirmed whether there is no abnormality in the voltage displacement after the lapse of time. If there is no abnormality, the process proceeds to step S26, and if there is an abnormality, the process proceeds to step S19. At this time, the predetermined pause time is, for example, based on the map shown in FIG. 7, the pause times are t _CS2 [seconds] and t _CS3 [seconds] in the second level and the third level, respectively. In the level, the determination value v _C2 [mV] is used, and in the third level, the determination value v _C3 [mV] is used.

  Here, with reference to FIGS. 14A and 14B, the determination of normality and abnormality of the voltage displacement due to the suspension after charging at the second level and the third level will be described.

After completion of charging at the second level and the third level, when a predetermined pause time is provided and the voltage displacement of each cell of the battery module 21 is checked, if there is no abnormality in each cell of the battery module 21 As shown in FIG. 14 (a), the battery voltage of each cell does not change even if time elapses, and the voltage displacement after elapse of a predetermined rest time is determined as a determination value (second-level determination value v). _C2 [mV] or the third level judgment value v _C3 [mV]).

On the other hand, when there is an abnormality in the cells of the battery module 21, as shown in FIG. 14 (b), there is a cell in which the battery voltage decreases with the passage of time, and each cell after a predetermined pause time has elapsed. The voltage displacement does not fall within the range of the judgment value (second level judgment value v _C2 [mV] or third level judgment value v _C3 [mV]), and the battery voltage varies and is judged to be abnormal. can do.

  In this case as well, normality / abnormality is determined by the variation in battery voltage after the lapse of the quiescent time, but the variation in battery voltage difference before and after the quiescent time and the amount of displacement per unit time of the battery voltage during the quiescent time Normality or abnormality may be determined based on variations in the

(Step S26)
When there is no abnormality in voltage displacement, as shown in Table 1, the second level has a constant discharge current value i _D / 2 [A] at the second level, and the third level has a constant at the third level. Discharge is started using the discharge current value i _D [A].

At this time, for example, based on the combination map shown in FIG. 8, at the second level, the cooling of the DC / DC converter 33 and the air conditioner 32 is operated to discharge at i _D / 2 [A]. At the third level, the DC / DC converter 33, the heating of the air conditioner 32, and the heater 31 (defroster heater) are operated to discharge at i _D [A]. The electric discharge is performed by operating an on-vehicle device that generates an electric load mounted on the vehicle 10, but when a large load is required such that the electric current value of the discharge becomes i _D [A], the air conditioner 32 is 3 Since about 5 kW, the heater 31 is about 5 kW, and the DC / DC converter 33 is about 1 kW, the discharge at i _D [A] can be performed by using all of them in combination.

(Step S27)
While detecting the battery voltage of each cell of each battery module 21 via the BMU 24 and the cell monitor unit 22, the discharge is continued until a predetermined discharge time elapses. At this time, the predetermined discharge time is, for example, the discharge time t _D2 [seconds] at the second level and the discharge time t _D3 [seconds] at the third level based on the map shown in FIG.

(Step S28)
After elapse of a predetermined discharge time, the battery voltage displacement of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22 to check whether there is any abnormality in the voltage displacement. The process proceeds to S29, and if there is an abnormality, the process proceeds to Step S19. At this time, the determination value is determined using, for example, the determination value v _D2 [mV] at the second level and the determination value v _D3 [mV] at the third level based on the map shown in FIG.

  Here, with reference to FIGS. 15A and 15B, the determination of normality and abnormality of the voltage displacement due to the second level and third level discharge will be described.

When the discharge at the second level and the third level is started in each cell of the battery module 21 after the suspension, if there is no abnormality in each cell of the battery module 21, as shown in FIG. As the battery voltage decreases, the battery voltage of each cell is equal to or higher than the use lower limit voltage and the determination value (second level) even after a predetermined discharge time has elapsed. The determination value v _D2 [mV] or the third level determination value v _D3 [mV]).

On the other hand, when there is an abnormality in the cell of the battery module 21, the battery voltage decreases as time passes, as shown in FIG. 15 (b). Then, after a predetermined discharge time has elapsed, the battery voltage of each cell is a battery voltage that is equal to or higher than the use lower limit voltage, but the determination value (the second level determination value v _D2 [mV] or the third level determination value v). _D3 [mV]), the battery voltage varies, and it can be determined that there is an abnormality.

  In this case as well, normality / abnormality is determined by the variation in battery voltage after the end of discharge, but due to variations in the battery voltage difference before and after the discharge, variations in the amount of displacement per unit time of the battery voltage during discharge, etc. Normal or abnormal may be determined.

(Step S29)
If there is no abnormality in the voltage displacement, the discharge is stopped.

(Step S30)
After the discharge is stopped, a predetermined rest time (OCV stabilization time) is provided again. During the rest time, the battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22, and the predetermined time. If there is no abnormality in the voltage displacement after the elapse of the rest time, the process proceeds to step S31. If there is an abnormality, the process proceeds to step S19. At this time, for example, based on the map shown in FIG. 7, the predetermined pause time is set to t _DS2 [seconds] and t _DS3 [seconds] for the second level and the third level, respectively. The determination value v _D2 [mV] is used at the level, and the determination value v _D3 [mV] is used at the third level. The normal / abnormal determination here is performed in the same manner as in FIGS. 14A and 14B described above except for the downtime and the determination value. Therefore, the description thereof is omitted here. .

(Step S31)
It is determined whether or not n = 3. If n = 3, the process proceeds to step S32. That is, if the determination procedure from the first level to the third level is completed and there is no abnormality, the process proceeds to step S32. On the other hand, if n = 3 is not true, the process returns to step S20, 1 is further added to the level number n (n = n + 1), and the process returns to step S8. In step S8, it is confirmed whether or not the level number n is 2 or more. In this case, since n = 3, the process proceeds to step S21, and the above-described steps S21 to S30 are performed.

  Even if the vehicle 10 is left unattended for a long time, even if each cell of each battery module 21 is in an overdischarged state and is below the lower limit voltage (see FIG. 5), the above steps S1 to S31 will be described. As described above, charging is performed at current values of multiple levels, and the battery voltage displacement at that time is confirmed. Similarly, discharging is performed at current levels of multiple levels, and the battery voltage displacement at that time is changed. As a battery function, it is possible to determine whether or not all cells are normal and to determine whether or not the cells can be recharged. As described above, by performing the check at a plurality of levels, it is possible to accurately determine whether or not recharging is possible even in a situation where the battery is easily influenced by the environmental temperature of the battery or the deterioration variation for each cell.

  In addition, here, since the charge / discharge check is performed with the current value of a plurality of levels, with a low current value at the beginning and a higher current value as the level becomes higher, the load on the battery that may be deteriorated is reduced. In addition, it is possible to determine whether or not recharging is possible with higher accuracy.

  In addition to the battery voltage displacement, the battery temperature displacement (increase) can be detected and the presence or absence of abnormality can be determined by the amount of heat generated. However, the battery temperature is usually not the temperature inside the battery but the outside Since it is the temperature of the surface (case or electrode), and the detected temperature is slower in response than the voltage (sensitivity is dull), the battery temperature may be used as a reference value to determine whether it is possible.

(Step S32)
When the first to third level determination procedures described above are completed and there is no abnormality, discharging is started. For example, on the basis of the combination map shown in FIG. 8, the devices used at the third level, specifically, the DC / DC converter 33, the heating of the air conditioner 32, the heater 31 (defroster heater), etc. are actuated to start discharging. To do.

(Step S33)
Check each device of the vehicle using the discharge current. For example, the operation check of the device shown in FIG. 8 may be performed. In particular, an operation check of an essential device at the time of traveling, for example, a defroster heater among the heaters 31 or a brake negative piezoelectric pump 34 is performed. Is desirable. In addition, you may perform the check of each apparatus not only at this step but at the time of the discharge check in a 1st level-a 3rd level (refer step S15, S27).

(Step S34)
After checking the operation of each device, the battery voltage of each cell of each battery module 21 is detected via the BMU 24 and the cell monitor unit 22, and discharging is continued until the battery voltage reaches the lower limit voltage. Here, in order to calculate the battery capacity more accurately in a later procedure, complete discharge is performed (state of charge (SOC) 0% state). When the battery voltage reaches the use lower limit voltage, the process proceeds to step S35.

(Step S35)
Discharge is stopped when the battery voltage reaches the lower limit voltage.

(Step S36)
Normal charge control is started from the SOC 0% state. For example, when the power cable from the quick charger is connected to the quick charge connector 25, each battery module 21 of the battery unit 20 is charged with a large current in a short time of about 30 minutes. When a power cable from a household outlet is connected to the normal charging connector 26, each battery module 21 of the battery unit 20 is charged with a normal current (for example, about 15 A) over several hours to several tens of hours. Like to do.

(Steps S37 to S39)
Along with the start of charging, the BMU 24 and the cell monitor unit 22 are used to start current capacity integration in which the current used for charging is integrated over the charging time, and when charging is completed, the integrated capacity is calculated. Further, the battery temperature at this time is detected using the BMU 24 and the cell monitor unit 22.

(Step S40)
Based on the calculated integrated capacity and the detected battery temperature, the usable capacity of each cell of each battery module 21 is corrected.

  Specifically, in each cell, the calculated integrated capacity is divided by its initial capacity to calculate the current capacity maintenance ratio, that is, the capacity maintenance ratio in a state where the capacity is reduced due to deterioration due to overdischarge. Based on the calculated capacity maintenance rate and the detected battery temperature, the correction coefficient can be obtained from the correction coefficient map based on the battery temperature and the capacity maintenance rate shown in FIG. Then, the maximum usable capacity that becomes the maximum (100%) can be obtained by dividing the calculated integrated capacity by the correction coefficient obtained from the map of FIG. By dividing the integrated capacity accumulated during normal charging control by the maximum usable capacity based on the maximum usable capacity obtained in this way, the usable capacity at that time can be calculated. By performing such calculation, the remaining battery level of the battery unit 20 can be grasped more accurately. The correction coefficient map based on the battery temperature and the capacity maintenance ratio as shown in FIG. 9 may be set as appropriate according to the type and capacity of the battery used.

In this embodiment, the charging times t _C2 [seconds] and t _C3 [seconds] in the charging check and the discharging times t _D1 [seconds], t _D2 [seconds] and t _D3 [seconds] in the discharging check are, for example, The battery is set to several tens of seconds to several hundred seconds, and the voltage displacement of the battery during that time is measured and determined to determine whether recharging is possible. When the voltage displacement at the time of charging or discharging the battery is checked in detail, it is suddenly displaced immediately after the start of charging or discharging (for example, within 0.1 [second]), and thereafter, it is gradually displaced. When the battery is progressively deteriorated, the amount of voltage displacement immediately after the start of charging or discharging becomes larger. Accordingly, whether or not the battery can be recharged is determined based on the voltage displacement of the battery within a predetermined time (for example, within 0.1 [second]) immediately after the start of each charge check and discharge check. Good. This makes it possible to determine whether or not the battery can be recharged in a short time. Further, since the voltage displacement within the predetermined time increases as the battery temperature decreases, the determination value of the voltage displacement that is determined to be abnormal may be increased as the battery temperature decreases.

  The present invention determines whether or not a battery can be recharged, and is particularly suitable for determining whether or not a battery can be recharged after overdischarge.

10 Vehicle 20 Battery Unit 21 Battery Module 22 Cell Monitor Unit 24 Battery Management Unit (BMU)
25 Fast Charging Connector 26 Normal Charging Connector 27 Car Charger 31 Heater 32 Air Conditioner 33 DC / DC Converter 34 Brake Negative Piezoelectric Pump 35 Integrated ECU

Claims (8)

Voltage measuring means for measuring the voltage of the driving battery mounted on the electric vehicle;
Control means for controlling charging and discharging of the battery;
Determining means for determining whether or not the battery can be charged based on the displacement of the voltage measured by the voltage measuring means;
The control means, when the voltage of the battery is equal to or lower than the use lower limit voltage defined for the battery,
A charge check that measures the voltage displacement of the battery while charging the battery using a predetermined charge current value or a predetermined charge power value, and a predetermined discharge current value or a predetermined discharge power after the charge check. While discharging from the battery using a value, repeatedly with a discharge check that measures displacement of the voltage of the battery alternately several times,
The determination means includes
A battery chargeability determination device that determines whether or not the battery can be charged based on a change in voltage of the battery in each of the charge check and the discharge check. The battery chargeability determination device according to claim 1,
The control means includes
The predetermined charging current value and the predetermined discharging current value, or the predetermined charging power value and the predetermined discharging power value are sequentially increased every time the charging check and the discharging check are repeated. Battery chargeability determination device. In the battery chargeability determination device according to claim 2,
A plurality of the batteries are mounted on the electric vehicle,
The determination means includes
When there is a battery in which the displacement of the battery voltage in each of the charge check and the discharge check is equal to or higher than a first determination value for determining abnormality, it is determined that charging is not possible,
The first determination value is
An apparatus for determining whether or not a battery can be charged is set to be larger each time the charge check and the discharge check are repeated. In the battery chargeability determination device according to claim 3,
The first determination value is
When the charge check and the discharge check are performed using the predetermined charge power value and the predetermined discharge power value, they are set smaller than when the predetermined charge current value and the predetermined discharge current value are used. An apparatus for determining whether or not a battery can be charged. In the battery chargeability determination device according to any one of claims 1 to 4,
The control means includes
An apparatus for determining whether or not a battery can be charged is characterized in that the current or power of the battery during the discharge check is consumed using a device mounted on the vehicle. In the battery chargeability determination device according to claim 5,
The control means includes
An apparatus for determining whether or not a battery can be charged is characterized in that an operation of a device mounted on the vehicle is confirmed using current or electric power of the battery at the time of the discharge check. In the battery chargeability determination device according to any one of claims 1 to 6,
The control means includes
After the charge check and after the discharge check, providing a rest time that becomes a stable time of the open circuit voltage of the battery, measuring the displacement of the battery voltage in the rest time,
The determination means includes
An apparatus for determining whether or not a battery can be charged based on whether or not the battery is charged based on a change in voltage of the battery during the pause time. In the battery chargeability determination device according to claim 7,
The determination means includes
When there is a battery in which the displacement of the battery voltage during the pause time is equal to or higher than a second determination value for determining abnormality, it is determined that charging is not possible,
The second determination value is
An apparatus for determining whether or not a battery can be charged is set to be larger each time the charge check and the discharge check are repeated.

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