JP5888215B2 - Battery system - Google Patents

Description

  The present invention relates to a battery system that performs charge / discharge control of a storage battery according to the state of charge of the storage battery.

  The storage battery has a discharge limit point and a charge limit point in a state of charge (SOC). When the SOC falls below the discharge limit point during discharge, the storage battery is overdischarged, and the output voltage is rapidly reduced. For this reason, when the SOC of the storage battery falls below the discharge limit point, it is difficult to supply power to the external device. In addition, if the SOC of the storage battery exceeds the charging limit point during charging, the storage battery is overcharged, which causes deterioration of the storage battery, such as causing irreversible electrolysis of the storage battery electrolyte. Therefore, it is desirable to control the SOC of the storage battery so as to belong to the charge / discharge region from the discharge limit point to the charge limit point.

  When the size of the charge / discharge region is expressed by the discharge capacity, it is the usable capacity of the storage battery and corresponds to the full charge capacity. In this case, the full charge capacity can be calculated from the charge / discharge current flowing in the storage battery and the open-circuit voltage of the storage battery (Patent Document 1). By calculating the SOC using the full charge capacity and controlling the charge / discharge based on the SOC, the SOC can be controlled to belong to the reference charge / discharge region.

JP 2008-241358 A

  The full charge capacity becomes maximum when the temperature of the storage battery is a reference temperature (for example, 25 ° C.). This maximum value of the full charge capacity is called the rated capacity. When the temperature of the storage battery is higher or lower than the reference temperature, the discharge limit point is large, the charge limit point is small, and the charge / discharge region is narrowed. Further, the full charge capacity of the storage battery is smaller than the rated capacity.

  Here, for example, in the case of an in-vehicle storage battery, it is assumed that charging / discharging of the storage battery is started with an ON operation of the power switch. At the start of this charge / discharge, the use (charge / discharge) of the storage battery is discontinuous between this time and the previous time, so it is considered that the temperature change of the storage battery occurs during the standing period. And it can be considered that due to this, the charge / discharge region in the charged state changes to the side to be narrowed. In this case, although the battery is not overcharged or overdischarged before the power switch is turned off, the charging state of the storage battery at the start of charging / discharging is set based on the temperature of the storage battery. There is a disadvantage that the battery is out of the discharge region and erroneously determined that the storage battery is overcharged or overdischarged.

  The present invention has been made in view of the above problems, and an object thereof is to appropriately perform charge / discharge control of a storage battery in accordance with a temperature change.

  According to the first aspect of the present invention, the respective limit points at a predetermined reference temperature are determined for the discharge limit point (LL) and the charge limit point (LH) relating to the state of charge of the storage battery (10), and each of these limit points is determined. The battery system is provided with a control means (20) for controlling charging / discharging of the storage battery in the reference charging / discharging region.

  Furthermore, a charge state calculation means (20) for calculating the charge state of the storage battery, a temperature detection means (50) for detecting the temperature of the storage battery, and the temperature detection means at the start of charging / discharging of the storage battery. When the temperature of the stored battery is in a temperature range different from the reference temperature, the charge / discharge region in the charged state at the detected temperature is set to at least one of the discharge limit point and the charge limit point. The first setting means (20) that shifts and sets the reference charge / discharge region to the narrowing side, and the charge state calculated by the charge state calculation means at the start of charge / discharge of the storage battery is the reference charge / discharge. In order to include the state of charge in the charge / discharge area when it is within the area and outside the charge / discharge area set by the first setting means, the first setting means The set charge-discharge regions, and the second setting means for resetting extended to either discharge limit point side or charge limit point side (20), characterized in that it comprises a.

  According to the above configuration, when the charge / discharge of the storage battery is started, the charge state of the storage battery is within the reference charge / discharge area and outside the charge / discharge area set according to the battery temperature. The charge / discharge region set according to the battery temperature is expanded and reset to either the discharge limit point side or the charge limit point side. By this resetting, it is possible to avoid that the state of charge of the storage battery goes out of the charge / discharge region, so that it is possible to suppress inconveniences such as erroneous determination of overcharge or overdischarge of the storage battery.

  Further, in this case, the charge state is out of the region from the charge / discharge region set based on the temperature of the storage battery at that time, but the charge state is the charge / discharge region ( Reference charge / discharge region) is assumed to have been maintained, and it is considered that the battery is not in a state of charge that is overdischarged or overcharged. For this reason, even if the charge / discharge region is expanded and reset as described above, overcharge and overdischarge are not substantially overlooked.

The system block diagram concerning one Embodiment. The figure which shows the relationship between absolute SOC and OCV. The figure which shows the charging / discharging characteristic of a storage battery. The figure which shows the temperature characteristic of a discharge limit point and a charge limit point. The figure which shows the setting of a charging / discharging area | region. The flowchart which shows the charging / discharging area | region calculation process concerning the embodiment. The flowchart which shows the absolute SOC calculation process concerning the embodiment. The flowchart which shows the effective SOC calculation process concerning the embodiment. The flowchart which shows the charging / discharging control process concerning the embodiment. The timing chart which shows the operation | movement of the embodiment. The flowchart which shows the charging / discharging area | region calculation process in a modification.

  An embodiment in which a battery system is applied to a hybrid vehicle as a power supply device will be described with reference to the drawings. FIG. 1 shows a system configuration according to the present embodiment.

  The illustrated storage battery 10 is a secondary battery such as a lithium ion storage battery. The storage battery 10 is, for example, an assembled battery in which battery cells are connected in series. Storage battery 10 is connected to first motor generator 12 via main relay MR and inverter 11. The rotor of the first motor generator 12 is mechanically coupled to the crankshaft of the engine 13 that is an internal combustion engine. The first motor generator 12 functions as a generator that converts the power of the crankshaft into electric energy, and functions as an initial rotation imparting means (starter) that imparts initial rotation to the crankshaft when the engine 13 is stopped. Have

  The storage battery 10 is connected to the second motor generator 15 via the main relay MR and the inverter 14. The second motor generator 15 is an in-vehicle main machine, and its rotor is mechanically coupled to the drive wheels.

  In the present embodiment, the first motor generator 12, the second motor generator 15, and the engine 13 are controlled by a control device (not shown) that controls them, so that the HV mode for driving the engine 13 and the engine 13 are stopped. The EV mode in which the vehicle travels in the state is selected as appropriate.

  A voltage sensor 30 that detects the output voltage is connected to the storage battery 10. The voltage sensor 30 detects the output voltage and outputs a detection signal Sv. The detection signal Sv is input to the control device 20 that controls the storage battery 10. The storage battery 10 is connected to a current sensor 40 that detects an output current that is the charge / discharge current. The current sensor 40 detects the output current and outputs a detection signal Si. The detection signal Si is input to the control device 20.

  The storage battery 10 is connected to a temperature sensor 50 that detects the temperature. Here, the temperature sensor 50 measures the surface temperature of the cell case that houses the battery cell in the outer case of the storage battery 10. In addition, you may measure the temperature of the internal solution of a battery cell. The temperature sensor 50 detects the temperature of the storage battery 10 and outputs a detection signal St. The detection signal St is input to the control device 20.

  The control device 20 acquires detected values of the output voltage, output current, and temperature of the storage battery 10 based on the input detection signals Si, Sv, St. The control device 20 calculates the SOC of the storage battery 10 based on the acquired voltage value of the output voltage of the storage battery 10 and the current value of the output current, and controls charging / discharging of the storage battery 10 according to the calculated SOC.

  A method for calculating the SOC of the storage battery 10 by the control device 20 will be described below. Here, the discharge capacity that can be used in the storage battery 10 is referred to as a full charge capacity Ahf. The full charge capacity Ahf varies depending on the temperature and becomes maximum at the reference temperature (25 ° C.). The maximum value of the full charge capacity Ahf is referred to as the rated capacity Ah0. The ratio of the current charge amount of the storage battery 10 to the rated capacity Ah0 is called absolute SOC, and the ratio of the current charge amount of the storage battery 10 to the full charge capacity Ahf is called effective SOC.

  FIG. 2 shows the relationship between the open-circuit voltage (OCV) and the absolute SOC. The OCV is an output voltage of the storage battery when no charge / discharge current flows through the storage battery. As shown in the figure, the OCV and the absolute SOC have a one-to-one relationship. The control device 20 holds the relationship between the OCV and the absolute SOC as a map. The control device 20 acquires the OCV of the storage battery 10 by acquiring the output voltage of the storage battery 10 in a state where no current flows from the detection signal Sv. The control device 20 calculates the absolute SOC of the storage battery 10 using the OCV-absolute SOC map based on the acquired OCV voltage value.

  Further, by integrating the current value I of the charge / discharge current flowing through the storage battery 10 with time, the change amount ΔAh of the charge amount can be calculated (ΔAh = ∫Idt). The change amount ΔAh of the charge amount, the change amount ΔSOC of the absolute SOC, and the rated capacity Ah0 have a relationship of “ΔAh = Ah0 × ΔSOC”. Therefore, the change amount ΔSOC of the absolute SOC can be calculated as “ΔSOC = ΔAh / Ah0”. When the current flows through the storage battery 10, the current value of the absolute SOC can be calculated by adding the absolute SOC change ΔSOC to the absolute SOC calculated based on the OCV.

  As shown in FIG. 1, a cooling fan 60 that cools the storage battery 10 is connected to the control device 20. The control device 20 operates as a temperature control unit, changes the rotational speed of the cooling fan 60 based on the input detection signal St, and sets the temperature of the storage battery 10 to a temperature suitable for charging / discharging the storage battery 10. Control close to temperature (25 ° C.) is performed.

  The control device 20 has a function of opening and closing the main relay MR based on ON / OFF of an IG (ignition) switch and the SOC of the storage battery 10. The control device 20 controls the main relay MR to be in an on state during a period in which the IG switch is in an on state, and performs charge / discharge in the storage battery 10. Further, when the SOC of the storage battery 10 is small, the control device 20 controls the main relay MR to connect the first motor generator 12 and the storage battery 10, and the electric power generated in the first motor generator 12 is stored in the storage battery 10. To charge. In addition, when the SOC of the storage battery 10 is large, the control device 20 controls the main relay MR to cut off the connection between the first motor generator 12 and the storage battery 10, thereby supplying power from the first motor generator 12. Stop. Note that, instead of controlling the main relay MR by the control device 20, the control device 20 controls the inverters 11 and 14 based on the SOC of the storage battery 10 to control charging / discharging of the storage battery 10. Good.

  FIG. 3 shows the relationship between the absolute SOC of the storage battery 10, the output voltage, and the temperature.

  At the reference temperature (25 ° C.), the absolute SOC of the storage battery 10 changes in the charge / discharge region where LL0 (0%) is the lower limit and LH0 (100%) is the upper limit as the storage battery is charged and discharged. When the absolute SOC of the storage battery 10 approaches LL0 (0%) during discharging, the output voltage rapidly decreases. When the absolute SOC reaches LL0 (0%), it becomes difficult to drive the second motor generator 15 and the first motor generator 12 as the output voltage of the storage battery 10 decreases. An absolute SOC at which the output voltage becomes lower than a predetermined voltage during discharge is called a discharge limit point LL. When the temperature of the storage battery 10 becomes lower than the reference temperature (25 ° C.), the discharge limit point LL shifts in a direction of increasing from LL0 (0%).

  In addition, when the absolute SOC rises from LH0 (100%) during charging, irreversible electrolysis of the electrolyte of the storage battery 10 increases, leading to deterioration of the storage battery 10. The absolute SOC at which this irreversible electrolysis increases from a predetermined amount during charging is referred to as a charging limit point LH. When the temperature of the storage battery 10 becomes lower than the reference temperature (25 ° C.), the charging limit point LH shifts in a direction of decreasing from LH0 (100%).

  The size of the charge / discharge region becomes maximum at the reference temperature (25 ° C.), and the charge / discharge region at the reference temperature (25 ° C.) is referred to as a reference charge / discharge region. When the temperature of the storage battery 10 is the reference temperature (25 ° C.), charging and discharging can be performed in all regions where the absolute SOC is 0% to 100%.

  The charge / discharge region shifts to a side narrower than the reference charge / discharge region when the temperature of the storage battery 10 becomes lower than the reference temperature. As shown in the figure, when the temperature of the storage battery 10 is low (−10 ° C.), the discharge limit point LL is LL1 (20%) and the charge limit point LH is LH1 (80%). That is, when the temperature of the storage battery 10 is low (−10 ° C.), a region where the absolute SOC is LL1 or more and LH1 or less is a charge / discharge region. Here, a region where the absolute SOC is smaller than the discharge limit point LL is called an overdischarge region, and a region larger than the charge limit point LH is called an overcharge region.

  FIG. 4 shows a temperature characteristic diagram of the discharge limit point LL and the charge limit point LH. In the illustrated example, a region in which the temperature of the storage battery 10 is 10 ° C. to 35 ° C. including the reference temperature 25 ° C. is defined as the reference temperature region. The lower temperature side is the lower temperature range and the higher temperature side is the higher temperature range than the reference temperature range.

  In the reference temperature range, the discharge limit point LL is 0% and the charge limit point LH is 100%. In the reference temperature region, the charge / discharge region A1 is a reference charge / discharge region. Further, in the low temperature range where the temperature of the storage battery 10 is 10 ° C. or less, the discharge limit point LL is shifted to a larger side and the charge limit point LH is shifted to a smaller side. That is, the charge / discharge region A1 shifts to a side narrower than the reference charge / discharge region.

  Moreover, if charging / discharging is performed from the storage battery 10 in the region where the temperature of the storage battery 10 is higher than the reference temperature (25 ° C.) (35 ° C. or more), the storage battery 10 becomes overheated and the progress of deterioration of the storage battery 10 is accelerated. Therefore, in the region (35 ° C. to 50 ° C.) in which the temperature of the storage battery 10 is higher than the reference temperature (25 ° C.), the control device 20 shifts the charging limit point LH in a direction to decrease from LH0 (100%), The discharge limit point LL is shifted in a direction increasing from LL0 (0%).

  Here, in the low temperature region and the high temperature region, the region where the absolute SOC is the discharge limit point LL to the charge limit point LH is the charge / discharge region A1, the region where the absolute SOC is 0% to the discharge limit point LL is the overdischarge region A2, and the charge limit point. The region where LH to 100% is the overcharge region A3. The control device 20 holds the temperature characteristics of the discharge limit point LL and the charge limit point LH shown in FIG. 4 as a map and uses it for the charge / discharge region setting process of the storage battery 10.

  FIG. 5 shows the setting of the charge / discharge area A1, the overdischarge area A2, and the overcharge area A3 in the present embodiment. In the example shown in FIG. 5A, the temperature of the storage battery 10 is low (−10 ° C.), the discharge limit point LL is LL1 (20%), and the charge limit point LH is LH1 (80%).

  As shown in FIG. 5 (A), the control device 20 sets the region where the absolute SOC is the discharge limit point LL to the charge limit point LH as the charge / discharge region A1, and the region where the absolute SOC is 0% to the discharge limit point LL as the overdischarge region. A2 is set as the overcharge region A3, and the region where the charge limit point LH is 100% is set. That is, the upper limit value A1_MAX of the charge / discharge region A1 is equal to the charge limit point LH, and the lower limit value A1_MIN is equal to the discharge limit point LL. And charging / discharging control is performed so that absolute SOC belongs to the charging / discharging area | region A1. The full charge capacity Ahf of the storage battery 10 corresponds to the charge / discharge area A1, and the rated capacity Ah0 corresponds to the reference charge / discharge area including all of the charge / discharge area A1, the overdischarge area A2, and the overcharge area A3. To do.

  If the control device 20 controls charging / discharging of the storage battery 10 so that the absolute SOC of the storage battery 10 always belongs to the charge / discharge area A1, the absolute SOC of the storage battery 10 belongs to the overdischarge area A2 or the overcharge area A3. Absent. However, if the control device 20 is turned off as the vehicle travels stopped, and the temperature of the storage battery 10 has changed during that time, the absolute SOC may belong to the overdischarge region A2 or the overcharge region A3.

  Even if the outside air temperature is low (−10 ° C.), when charging / discharging is performed in the storage battery 10, the storage battery 10 generates heat with power consumption at the internal resistance of the storage battery 10, and the temperature of the storage battery 10 is the reference temperature ( 25 ° C). Further, the temperature of the storage battery 10 is maintained at the reference temperature (25 ° C.) by the cooling by the cooling fan 60. When the IG switch is turned off and left in this state, the temperature of the storage battery 10 decreases to the outside air temperature (−10 ° C.).

  Even when the outside air temperature is close to the reference temperature (25 ° C.), if the temperature of the vehicle body increases due to sunlight or the like, the temperature of the storage battery 10 may rise to a high temperature (50 ° C.). When the IG switch is turned on, the control device 20 uses the cooling fan 60 to control the temperature of the storage battery 10, thereby maintaining the temperature of the storage battery 10 at the reference temperature (25 ° C.). However, when the IG switch is turned off, the control device 20 and the cooling fan 60 stop operating. When left in this state, the temperature of the storage battery 10 becomes high (50 ° C.).

  That is, at the timing when the IG switch is turned off, the temperature of the storage battery 10 is set to the reference temperature (25 ° C.), but during the period when the IG switch is turned off and left unattended, the temperature of the storage battery 10 is set as a reference. The temperature may be lower (−10 ° C.) or higher (50 ° C.) than the temperature (25 ° C.). In such a case, the charge / discharge region A1 at the timing when the IG switch is turned on again after being left is shifted to a side narrower than the charge / discharge region A1 at the timing when the IG switch is turned off.

  When the storage battery 10 is charged to near the charging limit point LH (LH0) at the timing when the IG switch is turned off, the absolute SOC of the storage battery 10 is as shown in the figure at the timing when the IG switch is turned on. It belongs to the overcharge area A3. Further, when the storage battery 10 is discharged to near the discharge limit point LL (LL0) at the timing when the IG switch is turned off, the absolute SOC of the storage battery 10 is overdischarged at the timing when the IG switch is turned on. It belongs to A2. In such a case, there is an inconvenience that the control device 20 erroneously determines that the storage battery 10 is in an overcharged state or an overdischarged state.

  Therefore, when the absolute SOC belongs to the overcharge region A3, as shown in FIG. 5B, the control device 20 resets the current value of the absolute SOC as the upper limit value A1_MAX of the charge / discharge region A1. Thereby, the current value of the absolute SOC belongs to the charge / discharge region A1, and the inconvenience that the storage battery 10 is erroneously determined to be in the overcharge state by the control device 20 can be suppressed.

  When the absolute SOC belongs to the overdischarge area A2, the control device 20 resets the current value of the absolute SOC as the lower limit value A1_MIN of the charge / discharge area A1. Thereby, the current value of the absolute SOC belongs to the charge / discharge region A1, and the inconvenience that the storage battery 10 is erroneously determined to be in the overdischarge state by the control device 20 can be suppressed.

  FIG. 6 shows a charge / discharge region setting process in the present embodiment. This charge / discharge region setting process is performed by the control device 20 at a predetermined cycle.

  In step S <b> 10, the temperature of the storage battery 10 is acquired from the temperature sensor 50. In step S11, the absolute SOC of the storage battery 10 calculated by the absolute SOC calculation process is acquired. FIG. 7 shows the absolute SOC calculation process in this embodiment. The absolute SOC calculation process is performed by the control device 20 with a period Δt.

  In step S30, it is determined whether or not the IG switch has just been switched from the off state to the on state. When a positive determination is made in step S30, the OCV of the storage battery 10 is detected in step S31. The process of step S31 is performed immediately after the IG switch is switched from the off state to the on state. For this reason, the charging / discharging current does not flow through the storage battery 10 at the timing of performing the process of step S31, and the OCV of the storage battery 10 can be detected by detecting the output voltage of the storage battery 10. In step S32, the current value of the absolute SOC is calculated based on the OCV, and the process ends.

  In step S30, when it is determined that the IG switch is not immediately after being switched from the off state to the on state (S30: NO), the current value I of the charge / discharge current of the storage battery 10 is acquired from the detection signal Si in step S33. . In step S34, based on the current value I, a change amount ΔSOC of the absolute SOC from the previous value is calculated. Specifically, the change amount of the charge / discharge capacity is calculated as the product of the current value I and the period Δt, and the change amount ΔSOC of the absolute SOC from the previous value is calculated by dividing the change amount of the charge / discharge capacity by the rated capacity Ah0. Is calculated (ΔSOC = I · Δt / Ah0). In step S35, the current value of the absolute SOC is calculated by adding the amount of change ΔSOC from the previous value of the calculated absolute SOC to the previous value of the absolute SOC, and the process ends.

  In step S12 in the charge / discharge region setting process shown in FIG. 6, the effective SOC of the storage battery 10 calculated by the effective SOC calculation process is acquired. FIG. 8 shows the effective SOC calculation process in the present embodiment. This effective SOC calculation process is performed by the control device 20 at a predetermined cycle.

  In step S40, the upper limit value A1_MAX of the charge / discharge region A1 is acquired. In step S41, the lower limit value A1_MIN of the charge / discharge region A1 is acquired. In step S42, the absolute SOC is acquired. In step S43, the effective SOC is calculated based on the upper limit value A1_MAX and lower limit value A1_MIN of the charge / discharge region A1 and the absolute SOC. Specifically, it is calculated as “effective SOC = (absolute SOC−A1_MIN) / (A1_MAX−A1_MIN)”.

  In step S13 in the charge / discharge region setting process shown in FIG. 6, it is determined whether or not it is immediately after the IG switch is switched to the on state. When an affirmative determination is made in step S13, a setting process for the charge / discharge region A1 at the start is performed in step S15 and subsequent steps.

  In step S15, the discharge limit point LL and the charge limit point LH are calculated based on the temperature of the storage battery 10 using the map shown in FIG. Next, in step S16, the discharge limit point LL is set as the lower limit value A1_MIN of the charge / discharge region A1, and the charge limit point LH is set as the upper limit value A1_MAX of the charge / discharge region A1. At this time, when the temperature of the storage battery 10 belongs to a high temperature region or a low temperature region, the charge / discharge region A1 is set to be shifted to the side where the reference charge / discharge region is narrowed. As a result, the lower limit value A1_MIN of the charge / discharge area A1 does not become LL0 (0%), and the overdischarge area A2 occurs. Further, the lower limit value A1_MAX of the charge / discharge region A1 does not become LH0 (100%), and the overcharge region A3 occurs.

  After setting the charge / discharge region A1 once in steps S15 and S16, in step S17, it is determined whether or not the temperature of the storage battery 10 belongs to a high temperature region or a low temperature region. In step S17, when the temperature of the storage battery 10 belongs to the reference temperature region (S17: NO), the charge / discharge region A1 is a reference charge / discharge region, and the overdischarge region A2 and the overcharge region A3 do not exist. For this reason, a process is complete | finished, without performing the reset process of charging / discharging area | region A1 in step S18-S21. When it is determined in step S17 that the temperature of the storage battery 10 belongs to the high temperature region or the low temperature region (S17: YES), the charge / discharge region A1 is reset in steps S18 to S21.

  In step S18, it is determined whether or not the absolute SOC is greater than the charging limit point LH. When it is determined that the absolute SOC is greater than the charging limit point LH (S18: YES), it means that the absolute SOC is outside the charge / discharge region A1, and the absolute SOC belongs to the overcharge region A3. In this case, in step S19, the charge / discharge area is expanded to the charge limit point LH side and reset to include the absolute SOC in the charge / discharge area A1. Specifically, the current value of the absolute SOC is reset as the upper limit value A1_MAX of the charge / discharge region A1, and the process ends.

  If it is determined that the absolute SOC is equal to or lower than the charging limit point LH (S18: NO), it is determined in step S20 whether or not the absolute SOC is smaller than the discharging limit point LL. When it is determined that the absolute SOC is smaller than the discharge limit point LL (S20: YES), it means that the absolute SOC is outside the charge / discharge area A1 and belongs to the overdischarge area A2. In this case, in step S21, the charge / discharge region is expanded to the discharge limit point LL side and reset to include the absolute SOC in the charge / discharge region A1. Specifically, the current value of the absolute SOC is reset as the lower limit value A1_MIN of the charge / discharge region A1. Thereafter, the process ends. Moreover, when it determines with absolute SOC being more than the discharge limit point LL (S20: NO), it means belonging to charging / discharging area | region A1. In this case, the process ends without resetting the charge / discharge region A1.

  In step S13, when it is determined that the IG switch is not immediately after being turned on (S13: NO), in step S14, it is determined whether the setting condition of the charge / discharge region at the time of non-starting is satisfied. . Here, the setting conditions of the charge / discharge region include that the difference between the temperature of the storage battery 10 when the IG switch is turned on and the current temperature of the storage battery 10 is a predetermined value or more, and that the effective SOC is an upper limit value. This includes approaching 100% and the effective SOC approaching the lower limit of 0%.

  If any one of the above conditions is satisfied (S14: YES), a charge / discharge area setting process at the time of non-starting is performed. That is, in step S22, the discharge limit point LL and the charge limit point LH are calculated based on the temperature of the storage battery 10 using the map shown in FIG. Next, in step S23, the discharge limit point LL is set as the lower limit value A1_MIN of the charge / discharge region A1, the charge limit point LH is set as the upper limit value A1_MAX of the charge / discharge region A1, and the process ends. In step S14, when it is determined that none of the setting conditions of the charge / discharge region is satisfied (S14: NO), the process is ended as it is.

  FIG. 9 shows the charge / discharge control process in this embodiment. The charge / discharge control process is performed by the control device 20 at a predetermined cycle. The control device that performs the charge / discharge region setting process, the absolute SOC calculation process, and the effective SOC calculation process, and the control device that performs the charge / discharge control process may be provided separately.

  In step S50, it is determined whether or not the effective SOC has reached 0%, that is, whether or not the lower limit value A1_MIN of the charge / discharge region A1 has been reached. If it is determined that the effective SOC has reached 0% (S50: YES), in step S51, the main relay MR is controlled to disconnect the connection between the second motor generator 15 and the storage battery 10, and from the storage battery 10 Discharging the second motor generator 15 is prohibited. In step S52, it is determined whether or not the effective SOC has reached 100%, that is, whether or not the upper limit value A1_MAX of the charge / discharge region A1 has been reached. If it is determined that the effective SOC has reached 100% (S52: YES), the main relay MR is controlled to disconnect the connection between the first motor generator 12 and the storage battery 10 in step S53, so that the first Charging the storage battery from the motor generator 12 is prohibited.

  The charge / discharge control of the storage battery 10 in this embodiment is demonstrated using the timing chart shown in FIG.

  Before the time Ta when the IG switch is turned off, the temperature of the storage battery 10 is maintained at the reference temperature (25 ° C.) by the heat generated by the charging and discharging of the storage battery 10 and the cooling fan 60 by the control device 20. For this reason, the upper limit value A1_MAX of the charge / discharge region A1 is set to 100%, and the lower limit value A1_MIN is set to 0%. And the absolute SOC of the storage battery 10 is 90% close to the upper limit value A1_MAX of the charge / discharge region A1.

  At time Ta, the IG switch is turned off and the main relay MR is turned off. As a result, no current flows through the storage battery 10, and charging / discharging in the storage battery 10 is stopped. As a result of stopping the charging / discharging in the storage battery 10, the heat generation of the storage battery 10 is stopped, and the temperature of the storage battery 10 decreases so as to approach the outside air temperature (for example, −10 ° C.).

  At time Tb, the IG switch is turned on, and the control device 20 acquires the temperature of the storage battery 10 from the temperature sensor 50. Using the temperature (−10 ° C.), the charge limit point LH and the discharge limit point LL of the storage battery 10 are calculated (LHb, LLb in the figure). Then, the charge limit point LH is set as the upper limit value A1_MAX of the charge / discharge region A1, and the discharge limit point LL is set as the lower limit value A1_MIN of the charge / discharge region A1. Further, immediately after the IG switch is turned on, the OCV of the storage battery 10 is acquired from the voltage sensor 30, and the absolute SOC of the storage battery 10 is calculated based on the acquired OCV (SOCb in the figure). This SOCb is the same as the absolute SOC (SOCa in the figure) when the IG switch is turned off at time Ta.

  Further, control device 20 compares the calculated absolute SOC with charge limit point LH and discharge limit point LL. At time Tb in the example shown in FIG. 10, the absolute SOC of the storage battery 10 is larger than the charging limit point LH, and the absolute SOC belongs to the overcharge region A3. Therefore, control device 20 resets upper limit value A1_MAX of charge / discharge region A1 for battery 10 to the absolute SOC at time Tb. Thereafter, the main relay MR is turned on, and the storage battery 10 is discharged to the MG2. As the battery discharges, the absolute SOC of the storage battery 10 decreases. The control device 20 acquires the current value I of the current flowing from the current sensor 40 to the storage battery 10 while the storage battery 10 is being charged / discharged, and calculates the absolute SOC of the storage battery 10 based on the integrated amount of the current value I. .

  At time Tc, since the effective SOC of the storage battery 10 decreases and changes to 20% or less, the control device 20 determines that the charge / discharge region setting condition is satisfied, and resets the charge / discharge region A1. That is, the control device 20 acquires the temperature of the storage battery 10 from the temperature sensor 50, calculates the charge limit point LH and the discharge limit point LL of the storage battery 10 using the temperature (LHc, LLc in the figure), and charges The discharge area A1 is set. Thereafter, the storage battery 10 continues to discharge, and the absolute SOC of the storage battery 10 reaches the lower limit value A1_MIN of the charge / discharge region A1. The control device 20 controls the main relay MR, connects the first motor generator 12 and the storage battery 10, and charges the storage battery 10. As the battery is charged, the absolute SOC of the storage battery 10 increases. At time Td, since the effective SOC of storage battery 10 increases and changes to 80% or more, control device 20 determines that the charging / discharging region setting condition is satisfied, and sets charging / discharging region A1. At time Td, since the temperature of the storage battery 10 has reached the normal temperature range (10 ° C. to 35 ° C.), the discharge limit point LL is LLd (0%) and the charge limit point LH is LHd (100%). The upper limit value A1_MAX of the charge / discharge area A1 is set as LHd (100%), the lower limit value A1_MIN is set as LLd (0%), and the charge / discharge area A1 becomes the reference charge / discharge area.

  The effects achieved by this embodiment will be described below.

  At the start of charging / discharging of the storage battery 10 in which the IG switch is switched from the off state to the on state, the charge / discharge region A1 is set according to the battery temperature. When the absolute SOC of the storage battery 10 is 0% to 100% and outside the charge / discharge region A1, the charge / discharge region A1 is on the discharge limit point LL side or the charge limit point LH. Extended to one of the sides and reset. By this resetting, it is possible to avoid that the actual absolute SOC of the storage battery 10 is outside the charge / discharge region A1, so that it is possible to suppress inconveniences such as erroneous determination of overcharge or overdischarge of the storage battery 10.

  Further, in this case, the absolute SOC is out of the range from the charge / discharge region A1 set based on the temperature of the storage battery 10 at that time, but the absolute SOC is charged / discharged during the previous charge / discharge period. It is assumed that it is maintained in the region A1 (reference charge / discharge region), and is not an absolute SOC that is overdischarged or overcharged. For this reason, even if the charge / discharge area A1 is expanded and reset as described above, overcharge and overdischarge are not substantially overlooked.

  Moreover, in the said structure, the area | region determination of absolute SOC is performed at the time of the start of charging / discharging of the storage battery 10 by which the IG switch was switched from the OFF state to the ON state. At the start of charging / discharging of the storage battery 10, no current flows through the storage battery 10. For this reason, since polarization does not occur in the storage battery 10, the OCV can be detected with high accuracy and the absolute SOC can be calculated with high accuracy. For this reason, determination of whether the absolute SOC of the storage battery 10 exists in the area | region of charging / discharging area | region A1 can be implemented suitably.

  When the absolute SOC belongs to the overcharge region A3, the region above the discharge limit point LL and above the absolute SOC when the region determination is made is reset as the charge / discharge region A1. By setting the charging / discharging area A1 in this way, it is possible to use the electric power suitably charged in the storage battery 10 without being in an overdischarged state at the time of discharging.

  When the absolute SOC belongs to the overdischarge area A2, the area above the absolute SOC and the charge limit point LH when the area determination is made is reset as the charge / discharge area A1. By setting the charging / discharging region A1 in this way, the storage battery 10 can be suitably charged without being overcharged during charging.

  The control device 20 performs control to bring the temperature of the storage battery 10 close to the reference temperature by the cooling fan 60. Thereby, at the time when the IG switch was previously turned off, it is assumed that the charge / discharge region A1 is maximized and becomes the reference charge / discharge region. And it is assumed that the control apparatus 20 is controlling so that the absolute SOC of the storage battery 10 belongs to the reference | standard charge / discharge area | region. For this reason, even when the absolute SOC of the storage battery 10 does not belong to the charge / discharge region A1 when the IG switch is turned on, if the temperature of the storage battery 10 is brought close to the reference temperature by the control of the control device 20, The absolute SOC of the storage battery 10 is considered to be within the charge / discharge area A1 again.

  The discharge limit point LL and the charge limit point LH change based on temperature. Therefore, the charge / discharge region A1 is set again on the condition that the temperature difference between the temperature of the storage battery 10 at the previous calculation of both limit points and the current temperature of the storage battery 10 exceeds a predetermined value. Thereby, the shift | offset | difference of the actual value and calculated value of both limit points can be reduced.

(Other embodiments)
-The control apparatus 20 may perform the charging / discharging area | region setting process shown in FIG. 11 instead of the charging / discharging area | region setting process shown in FIG. The charging / discharging area setting process shown in FIG. 11 adds the following processes (steps S60 and S61) between step S16 and step S17 in the charging / discharging area setting process shown in FIG.

  In step S60, the control device 20 compares the absolute SOC at the previous end of charge / discharge of the storage battery 10 with the absolute SOC of the storage battery at the start of charge / discharge of the storage battery 10, and the difference between the absolute SOCs is a predetermined value α. It is determined whether it is smaller. Specifically, the absolute SOC (SOCa) when the IG switch in FIG. 10 is turned off (time Ta) is compared with the absolute SOC (SOCb) when the IG switch is turned on (time Tb). It is determined whether the difference is larger than a predetermined value α. When the difference between SOCa and SOCb is equal to or smaller than the predetermined value α (S60: NO), the resetting process of the charge / discharge region A1 after step S17 is executed.

  If an affirmative determination is made in step S60, the absolute SOC of the storage battery at the start of charging / discharging of the storage battery 10 is compared with the discharge limit point LL in step S61, and the absolute SOC is equal to or greater than the discharge limit point LL. It is determined whether or not. Specifically, SOCb in FIG. 10 is compared with discharge limit point LL (LLb) at time Tb to determine whether SOCb is equal to or greater than LLb. When SOCb is LLb or more (S61: YES), a resetting process for the charge / discharge region A1 after step S17 is performed.

  If a positive determination is made in step S60 and a negative determination is made in step S61, that is, if the difference between SOCa and SOCb is larger than a predetermined value α and SOCb is smaller than LLb, step The charge / discharge area resetting process after S17 is not performed.

  When the IG switch is turned off and the storage battery 10 is left unattended for a long time, the absolute SOC of the storage battery 10 may be reduced to nearly 0% due to natural discharge during the storage period. In this case, even if the IG switch is turned on and the temperature control process of the storage battery 10 is performed by the control device 20, the storage battery 10 remains in the overdischarged state even when the temperature of the storage battery 10 approaches the reference temperature. Even in such a case, it is inconvenient to expand and reset the charge / discharge area A1. Therefore, the above inconvenience can be solved by adding the processes of steps S60 and S61.

  -In above-mentioned embodiment, when absolute SOC belongs to the overcharge area | region A3, you may set the area | region more than the discharge limit point LL and absolute SOC = 100% or less as the charging / discharging area | region A1. When the absolute SOC belongs to the overdischarge region A2, a region where the absolute SOC is 0% or more and the charge limit point LH or less may be set as the charge / discharge region A1. Even in such a case, it is possible to suppress inconveniences such as erroneous determination of overcharge or overdischarge.

  The setting of the charge / discharge area A1 may be performed every predetermined time on condition that a current flows through the storage battery 10. Thereby, charging / discharging area | region A1 can be set according to the temperature change by the heat_generation | fever in the internal resistance of the storage battery 10. FIG.

  DESCRIPTION OF SYMBOLS 10 ... Storage battery, 20 ... Control apparatus (charging condition calculation means, control means, 1st setting means, 2nd setting means), 50 ... Temperature sensor (temperature detection means).

Claims (6)

Regarding the discharge limit point (LL) and the charge limit point (LH) relating to the state of charge of the storage battery (10), the respective limit points at a predetermined reference temperature are determined, and the reference charge / discharge region is between these limit points. A battery system comprising control means (20) for controlling charge / discharge of the storage battery within the reference charge / discharge region,
Charging state calculation means (20) for calculating the charging state of the storage battery;
Temperature detecting means (50) for detecting the temperature of the storage battery;
At the start of charging / discharging of the storage battery, when the temperature of the storage battery detected by the temperature detection means is in a temperature range different from the reference temperature, the charge / discharge region of the charged state at the detected temperature is First setting means (20) for shifting and setting at least one of the discharge limit point and the charge limit point to a side narrowing the reference charge / discharge region;
Similarly, at the start of charging / discharging of the storage battery, the charging state calculated by the charging state calculating means is within the reference charging / discharging area and outside the charging / discharging area set by the first setting means. In order to include the state of charge in the charge / discharge region, the charge / discharge region set by the first setting means is expanded and reset to either the discharge limit point side or the charge limit point side. And a second setting means (20). The second setting means includes
When the charge state is smaller than the discharge limit point of the charge / discharge region set by the first setting means at the start of charge / discharge of the storage battery, the charge / discharge region is expanded to the charge state, 2. The battery system according to claim 1, wherein the charge / discharge area set by the one setting means is reset. The second setting means includes
At the start of charging / discharging of the storage battery, when the charging state is larger than the charging limit point of the charging / discharging region set by the first setting means, the charging / discharging region is expanded to the charging state, The battery system according to claim 1 or 2, wherein the charge / discharge region set by the one setting means is reset. A cooling fan (60) for supplying cooling air to the storage battery to cool the storage battery;
The battery system according to any one of claims 1 to 3, further comprising temperature control means (20) for controlling the temperature of the storage battery to approach the reference temperature using the cooling fan. . Said second setting means,
And the state of charge of the battery at the time of previous times of charge and discharge end, the difference between the state of charge of the battery at the start of this charging and discharging rather greater than the predetermined value, and, at the start of charging and discharging of the storage battery The charging / discharging area set by the first setting means is not reset when the state of charge of the storage battery is smaller than the discharge limit point of the charging / discharging area set by the first setting means. Item 5. The battery system according to any one of Items 1 to 4. The first setting means includes
Detected by the temperature detecting means on condition that the difference between the current detected temperature of the storage battery detected by the temperature detecting means and the detected temperature when the charge / discharge area was previously set is equal to or greater than a predetermined value. The battery system according to any one of claims 1 to 5, wherein a charge / discharge region is set based on a current detected temperature of the storage battery.

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