JP6493167B2 - Power system controller - Google Patents

Description

  The present invention relates to a control device for a power supply system that calculates and learns a resistance component or a capacity component constituting an equivalent circuit of an internal resistance of a storage battery.

  A technique is known in which the internal resistance of a storage battery is calculated, and abnormality or deterioration of the storage battery is determined from the calculated value. For example, Patent Document 1 describes a technique for obtaining a resistance value of an internal resistance by supplying a constant current to a storage battery.

JP 2014-85118 A

  The technique described in Patent Document 1 describes a configuration in which power is supplied from an external power source to the storage battery, but cannot be applied to a configuration that does not have means for supplying power from the external power source to the storage battery. Patent Document 1 also describes a configuration in which the resistance value of the internal resistance is calculated from the charge / discharge current of the storage battery and the inter-terminal voltage when power is supplied from the storage battery to the motor. However, it is difficult to maintain a constant current during driving of the motor, and it is difficult to maintain a constant current, and the adverse effect on the current sensor and voltage sensor due to radiation noise accompanying driving of the motor becomes a problem.

  An equivalent circuit of the internal resistance of the storage battery can be expressed as having a parallel circuit of a resistance component and a capacity component. The configuration described in Patent Document 1 is a configuration that learns only the resistance component of the internal resistance.

  The present invention has been made in view of the above problems, and an equivalent circuit of an internal resistance of a storage battery having a resistance component and a capacity component is used to supply power from the external power source to the storage battery. The main object of the present invention is to provide a control device for a power supply system that can learn without any problems.

  This configuration includes a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery, and is mounted on a vehicle. The control device (20) of the power supply system that controls the in-vehicle power supply system, wherein the equivalent circuit of the internal resistance (11) of the first storage battery has a resistance component (R1, R2) and a capacity component (C1, C2). ) And a parallel circuit (P1, P2), a detection value of a charge / discharge current flowing through the first storage battery from a current detection unit (25), and a terminal of the first storage battery from a voltage detection unit (26) An acquisition unit that acquires a detection value of an inter-voltage, and when the vehicle is in a parked state, an electric current is generated between the first storage battery and the second storage battery by operating the switch from an off state to an on state. Switch the switch from on to off. A switch operation unit that stops current flowing between the first storage battery and the second storage battery, and the charge / discharge current in the on and off states of the switch, and the detected value of the voltage between the terminals. And a learning unit that calculates a value of the resistance component or the capacitance component and learns the calculated value as a learning value.

  In the parking state, a current is passed between the first storage battery and the second storage battery by turning on the switch, and then a current between the first storage battery and the second storage battery is turned off by turning the switch off. It was set as the structure which stops. Since the charge / discharge current value changes in the first storage battery, the capacity value of the internal resistance and the learning value of the resistance component are calculated based on the detected value of the charge / discharge current and the detected value of the voltage between the terminals before and after the change. It becomes possible to do. In this configuration, since the first storage battery and the second storage battery are both mounted on the vehicle, the capacity component or the resistance component of the equivalent circuit of the internal resistance is not charged and discharged from the external power source to the in-vehicle power supply system. It becomes possible to learn the value.

  Furthermore, since various electric loads mounted on the vehicle, for example, power steering, motors, and starters are stopped in the parked state, the current value of the charge / discharge current becomes stable. In addition, since driving of various electric loads is stopped, radiation noise accompanying driving of the various electric loads can be suppressed, so that adverse effects on the learning value of the capacitance component or resistance component constituting the equivalent circuit of the internal resistance can be suppressed. .

The electrical block diagram of a power supply system. The figure showing the equivalent circuit of a lithium ion storage battery. The figure showing the change of the voltage between terminals accompanying the change of the charging / discharging electric current of a lithium ion storage battery. The figure showing the SOC-open end voltage characteristic of a lithium ion storage battery and a lead storage battery. The flowchart showing the circuit constant learning process of this embodiment. The timing chart showing the change of the charging / discharging electric current at the time of implementing control of this embodiment.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. A vehicle on which the in-vehicle power supply system of this embodiment is mounted travels using an engine (internal combustion engine) as a drive source, and has a so-called idling stop function.

  As shown in FIG. 1, the power supply system includes a lithium ion storage battery 10 (first storage battery), a MOS switch 15, an SMR switch 16, a rotating electrical machine 40, a lead storage battery 41 (second storage battery), a starter 44, and various electric loads. 45. Among these, the lithium ion storage battery 10 and each switch 15 and 16 are integrated by being accommodated in the housing | casing (accommodating case) which is not shown in figure, and is comprised as the battery unit U. FIG. Further, the battery unit U has a control device 20 that controls the in-vehicle power supply system, and the switches 15 and 16 and the control device 20 are accommodated in the casing in a state of being mounted on the same substrate. .

  The battery unit U is provided with a first terminal T1 and a second terminal T2 as external terminals. A lead storage battery 41, a starter 44, and an electric load 45 are connected to the first terminal T1, and a second terminal T2 is connected to the second terminal T2. A rotating electrical machine 40 is connected. The terminals T1 and T2 are both large current input / output terminals through which input / output currents of the rotating electrical machine 40 flow.

  The rotating shaft of the rotating electrical machine 40 is connected to an engine output shaft (not shown) by a belt or the like, and the rotating shaft of the rotating electrical machine 40 is rotated by the rotation of the engine output shaft. As a result, the engine output shaft rotates. In this case, the rotating electrical machine 40 includes a power generation function for generating power (regenerative power generation) by rotation of the engine output shaft and the axle, and a power output function for applying rotational force to the engine output shaft, and an ISG (Integrated Starter Generator). It is what constitutes.

  The lead storage battery 41 and the lithium ion storage battery 10 are electrically connected in parallel to the rotating electrical machine 40, and the storage batteries 10 and 41 can be charged by the generated power of the rotating electrical machine 40. The rotating electrical machine 40 is driven by power feeding from the storage batteries 10 and 41.

  The lead storage battery 41 is a known general-purpose storage battery. On the other hand, the lithium ion storage battery 10 is a high-density storage battery with less power loss in charge / discharge and higher output density and energy density than the lead storage battery 41.

  Specifically, the lead storage battery 41 is configured such that the positive electrode active material is lead dioxide (PbO2), the negative electrode active material is lead (Pb), and the electrolytic solution is sulfuric acid (H2SO4). And the some battery cell comprised from these electrodes is connected in series, and is comprised. In the present embodiment, setting is made such that the charge capacity of the lead storage battery 41 is larger than the charge capacity of the lithium ion storage battery 10.

  On the other hand, an oxide containing lithium (lithium metal composite oxide) is used for the positive electrode active material of the lithium ion storage battery 10, and specific examples include LiCoO2, LiMn2O4, LiNiO2, LiFePO4, and the like. As the negative electrode active material of the lithium ion storage battery 10, carbon (C), graphite, lithium titanate (for example, LixTiO2), an alloy containing Si or Sn, or the like is used. An organic electrolyte is used as the electrolyte of the lithium ion storage battery 10. And the some battery cell comprised from these electrodes is connected in series, and is comprised.

  In addition, the codes | symbols 12 and 43 in FIG. 1 represent the battery cell assembly of the lithium ion storage battery 10 and the lead storage battery 41, and the codes | symbols 11 and 42 represent the internal resistance of the lithium ion storage battery 10 and the lead storage battery 41.

  The electric load 45 includes a constant voltage required load that is required to be stable so that the voltage of the supplied power is substantially constant or varies at least within a predetermined range. Specific examples of the constant voltage request load include a navigation device and an audio device. In this case, stable operation of each of the above devices can be realized by suppressing voltage fluctuation. If the voltage input to the constant voltage request load fluctuates, the operation of the constant voltage request load stops and then restarts. The electrical load 45 includes an ECU 30 described later.

  In addition, examples of the electric load 45 include wipers such as a headlight and a front windshield, a blower fan for an air conditioner, and a heater for a defroster for a rear windshield. For these headlights, wipers, blower fans, etc., if the power supply voltage changes, the headlight blinks, the wiper operating speed changes, and the blower fan rotation speed changes (fan noise change). A constant voltage is required.

  The battery unit U is provided with connection paths 21 and 22 for connecting the terminals T1 and T2 and the lithium ion storage battery 10 to each other as an in-unit electrical path. Of these, a MOS switch 15 as an opening / closing means is provided in the first connection path 21 connecting the first terminal T1 and the second terminal T2, and a connection point N1 (battery connection point) on the first connection path 21 is provided. The SMR switch 16 is provided in the second connection path 22 that connects the lithium ion storage battery 10. Each of these switches 15 and 16 includes 2 × n MOSFETs (semiconductor switches) and is connected in series so that the parasitic diodes of the pair of MOSFETs are opposite to each other. When the switches 15 and 16 are turned off, the parasitic diode completely cuts off the current flowing through the path where the switches are provided.

  Further, in the present power supply system, a bypass path 23 is provided that enables the lead storage battery 41 and the rotating electrical machine 40 to be connected without using the MOS switch 15. Specifically, the bypass path 23 bypasses the battery unit U and is connected to the first terminal T1 (path connected to the lead storage battery 41 and the like) and the electrical path connected to the second terminal T2. It is provided so as to be electrically connected to the (path connected to the rotating electrical machine 40). On the bypass path 23, a bypass switch 24 is provided that switches the connection between the lead storage battery 41 side and the rotating electrical machine 40 side to a cut-off state or a conductive state. The bypass switch 24 is a normally closed relay switch. Note that the bypass path 23 and the bypass switch 24 may be provided so as to bypass the MOS switch 15 in the battery unit U.

  The control device 20 switches the switches 15 and 16 between on (closed) and off (open). In this case, the control device 20 is at the time of discharging (load driving) for supplying power to the electric load 45, charging at the time of charging by supplying power from the rotating electrical machine 40, or by idling stop control. The on / off state of the MOS switch 15 is controlled depending on whether the engine is automatically restarted by the rotating electrical machine 40 when the engine is stopped. The SMR switch 16 is basically maintained in an on (closed) state when the vehicle is running, and is turned off (opened) when any abnormality occurs in the battery unit U, the rotating electrical machine 40, or the like. .

  The control device 20 is connected to an ECU 30 outside the battery unit. That is, the control device 20 and the ECU 30 are connected via a communication network such as CAN and can communicate with each other, and various data stored in the control device 20 and the ECU 30 can be shared with each other. The ECU 30 is an electronic control device having a function of performing idling stop control. As is well known, the idling stop control is to automatically stop the engine when a predetermined automatic stop condition is satisfied, and to restart the engine when the predetermined restart condition is satisfied under the automatic stop state.

  The rotating electrical machine 40 generates power using the rotational energy of the engine output shaft. Specifically, when the rotor is rotated by the engine output shaft in the rotating electrical machine 40, an alternating current is induced in the stator coil according to the exciting current flowing in the rotor coil, and is converted into a direct current by a rectifier (not shown). Then, the excitation current flowing through the rotor coil in the rotating electrical machine 40 is adjusted by the regulator, so that the voltage of the generated direct current is adjusted to be a predetermined adjustment voltage Vreg.

  The electric power generated by the rotating electrical machine 40 is supplied to the electric load 45 and also supplied to the lead storage battery 41 and the lithium ion storage battery 10. When the driving of the engine is stopped and no electric power is generated by the rotating electrical machine 40, electric power is supplied from the lead storage battery 41 and the lithium ion storage battery 10 to the electric load 45. The discharge amount from the lead storage battery 41 and the lithium ion storage battery 10 to the electric load 45 and the charge amount from the rotating electrical machine 40 are ranges in which the SOC (the ratio of the actual charge amount to the full charge capacity, the charge rate) does not cause overcharge / discharge. It adjusts suitably so that it may become (SOC use field).

  In this case, the control device 20 limits overcharge protection to the lithium ion storage battery 10 by limiting the amount of charge to the lithium ion storage battery 10 so that the SOC of the lithium ion storage battery 10 is in a predetermined usage region (FIG. 4 described later). Protection control is performed so that the discharge amount from 10 is limited and overdischarge protection is performed. Specifically, the control device 20 constantly acquires the detected value of the charge / discharge current I of the lithium ion storage battery 10 from the current sensor 25 (current detection unit), and also acquires the detection value of the lithium ion storage battery 10 from the voltage sensor 26 (voltage detection unit). The detection value of the inter-terminal voltage V is always obtained. And the control apparatus 20 implements protection control based on the detected value of the voltage V between the terminals and the charging / discharging current I.

  When the voltage V between terminals of the lithium ion storage battery 10 is lower than the lower limit voltage, the control device 20 performs overdischarge protection of the lithium ion storage battery 10 by charging from the rotating electrical machine 40. The lower limit voltage may be set based on a voltage corresponding to the lower limit value of the SOC use region. Moreover, the control apparatus 20 implements overcharge protection by instructing variable setting of the adjustment voltage Vreg so that the inter-terminal voltage V of the lithium ion storage battery 10 does not rise above the upper limit voltage. The upper limit voltage may be set based on a voltage corresponding to the upper limit value of the SOC usage region.

  In addition, about the lead storage battery 41, the same protection control is implemented by another battery control apparatus which is not shown in figure. The control device 20 acquires the detected value of the inter-terminal voltage Vp of the lead storage battery 41 from the battery control device that controls the lead storage battery 41. The control device 20 may be configured to acquire a detection value from a voltage sensor that detects the inter-terminal voltage Vp of the lead storage battery 41.

  Further, in the present embodiment, the decelerating regeneration is performed in which the rotating electrical machine 40 is generated by the regenerative energy of the vehicle and is charged in both the storage batteries 10 and 41 (mainly the lithium ion storage battery 10). This deceleration regeneration is performed when conditions such as that the vehicle is decelerating and that fuel injection to the engine is cut are satisfied.

  In this embodiment, charging / discharging is performed by using the lithium ion storage battery 10 preferentially among the storage batteries 10 and 41. Specifically, at the time of regenerative power generation of the rotating electrical machine 40, the control device 20 turns off the MOS switch 15 and turns on the SMR switch 16, so that the generated power in the rotating electrical machine 40 is preferentially lithium. The ion storage battery 10 is charged. Further, when the rotating electrical machine 40 is driven, the control device 20 turns off the MOS switch 15 and turns on the SMR switch 16, so that the power consumption of the rotating electrical machine 40 is preferentially reduced from the lithium ion storage battery 10. Discharged.

  Here, the control device 20 of the present embodiment is configured based on the detection value of the charge / discharge current I of the lithium ion storage battery 10 and the detection value of the inter-terminal voltage V. The resistance components Rs, R1, R2 and the capacitance components C1, C2) are learned.

  An equivalent circuit of the lithium ion storage battery 10 is shown in FIG. The equivalent circuit of the lithium ion storage battery 10 includes an internal resistor 11 and a voltage source 12 excluding the internal resistor 11.

  The output voltage of the voltage source 12 is equal to the inter-terminal voltage V of the lithium ion storage battery 10 when no current flows in the lithium ion storage battery 10 in a steady state, that is, the open-circuit voltage. The internal resistance 11 includes a direct current resistance (Rs), a first reaction resistance (R1, C1) representing reaction resistance at the positive electrode and the negative electrode, and a second reaction resistance (R2) representing a reaction resistance different from the first reaction resistance. , C2) is configured as a series connection body of three sets of circuit constants. The first reaction resistance is represented as a parallel circuit P1 having a resistance component R1 and a capacitance component C1, and the second reaction resistance is represented as a parallel circuit P2 having a resistance component R2 and a capacitance component C2. In other words, the lithium ion storage battery 10 has resistance components Rs, R1, R2 and capacity components C1, C2 as circuit constants.

The value Rt of the internal resistance 11 of the lithium ion storage battery 10 can be calculated using the circuit constants Rs, R1, R2, the time constant τ1 of the first reaction resistance and the time constant τ2 of the second reaction resistance. Specifically, when the detected value of the current I flowing through the lithium ion storage battery 10 increases or decreases from a predetermined constant current Ia (for example, −10 A) to another constant current I0 (for example, 0 A), the start of the current change The internal resistance value Rt when the time t has elapsed from the time point is
Rt = Rs + R1 (1-exp (−t / τ1)) + R2 (1-exp (−t / τ2))
... (1)
Can be calculated as

  Here, the time constants τ1 and τ2 are τ1 = R1 · C1, τ2 = R2 · C2, and for example, τ1 is about 0.01 sec and τ2 is about 10 sec. Since the DC resistance has no capacitance component, the DC resistance time constant τs is 0 sec.

A voltage change Vt occurs in the internal resistance 11 by changing the current flowing through the internal resistance 11. The voltage change Vt (t) at time t generated in the internal resistance 11 of the lithium ion storage battery 10 with the current change is calculated using the internal resistance value Rt and the current change amount ΔI (ΔI = I0−Ia).
Vt (t)
= ΔI · Rt
= ΔI (Rs + R1 (1-exp (−t / τ1)) + R2 (1-exp (−t / τ2)))
= Vs + V1 (1-exp (-t / τ1)) + V2 (1-exp (-t / τ2))
... (2)
Can be expressed as

  In the above equation (2), Vs is a voltage change caused by a DC resistance (Vs = ΔI · Rs), V1 is a voltage change caused by a first reaction resistance in a steady state (V1 = ΔI · R1), and V2 is a steady state 2 Voltage change caused by reaction resistance (V2 = ΔI · R2).

  FIG. 3 shows the change over time of the detected value V (t) of the inter-terminal voltage when the detected value I (t) of the current flowing through the lithium ion storage battery 10 increases from Ia to I0. The voltage change Vt (t) is a value of the detected value V (t) of the inter-terminal voltage with respect to the reference voltage with the detected value V0a before the current change of the inter-terminal voltage at the start point (t = 0) of the current change as a reference voltage. The amount of change can be calculated (Vt (t) = V (t) −V0a).

  When the detected value I (t) of the current flowing through the lithium ion storage battery 10 increases from Ia to I0 as shown in FIG. 3, the circuit constant Rs of the equivalent circuit of the lithium ion storage battery 10 is based on the voltage change Vt (t). , R1, C1, R2, and C2 can be calculated. The calculation method is described below.

First, a calculation method of Rs, R1, and C1 among circuit constants Rs, R1, C1, R2, and C2 will be described. In the vicinity of time t1 when the time corresponding to the time constant τ1 has elapsed from the start time t = 0 of the current increase / decrease change, t << τ2. Therefore, the voltage change Vt (t) in the vicinity of time t1 is
Vt (t) = Vs + V1 (1-exp (−t / τ1)) (3)
And can be approximated.

  Here, a time range (0 to t1) starting from the current change start time t = 0 and ending at the time t = t1 when the time corresponding to the time constant τ1 has elapsed from the current change start time t = 0 is sampled. Set as period. Then, a voltage change Vt (t) at each time point is calculated from the detected value V (t) of the inter-terminal voltage acquired at each time point during the sampling period. Vs and V1 can be calculated by fitting the calculated voltage change Vt (t) to the above equation (3) and fitting.

  Using the calculated Vs, the learning value of the circuit constant Rs can be calculated as Rs = Vs / ΔI. Also, using the calculated V1, the learning value of the resistance component R1 in the first reaction resistance can be calculated as R1 = V1 / ΔI, and the learning value of the capacitance component C1 of the first reaction resistance is C1 = It can be calculated as τ1 / R1.

Next, a method for calculating the circuit constants R2 and C2 will be described. In the vicinity of time t2 when a time corresponding to the time constant τ2 has elapsed from the start time t = 0 of the current increase / decrease change, t >> τ1. Therefore, the voltage change Vt (t) in the vicinity of time t2 is
Vt (t) = Vs + V1 + V2 (1-exp (−t / τ2)) (4)
And can be approximated.

  Here, a predetermined time range t3 to t4 in the vicinity of the time t2 when the time corresponding to the time constant τ2 has elapsed from the start point t = 0 of the current change (for example, t3 = τ2 / 2, t4 = 3 · τ2 / 2). Is set as the sampling period. Then, the voltage change Vt (t) at each time point is calculated from the detected value V (t) of the inter-terminal voltage of the lithium ion storage battery 10 acquired in the sampling period. Then, V2 can be calculated by fitting the voltage change Vt (t) to the above equation (3) and fitting.

  Using the calculated V2, the learning value of the resistance component R2 of the second reaction resistance can be calculated as R2 = V2 / ΔI, and the learning value of the capacitance component C2 of the second reaction resistance is C2 = τ2 / It can be calculated as R2.

  When fitting the voltage change Vt (t), a non-linear least square method such as a differential correction method may be used.

  The control device 20 in the present embodiment learns the circuit constants Rs, R1, R2, C1, and C2 of the internal resistance 11 described above when the vehicle is parked. When the vehicle is parked, both the MOS switch 15 and the SMR switch 16 are turned on. When the lithium ion storage battery 10 and the lead storage battery 41 are connected by turning on the switches 15 and 16, the lithium ion storage battery 10 is caused by the potential difference between the open end voltage of the lithium ion storage battery 10 and the open end voltage of the lead storage battery 41. Charge / discharge current I flows between the lead battery 41 and the lead storage battery 41. Here, the parking state is a state where the vehicle is continuously stopped. In the parking state, the operations of the rotating electrical machine 40 and the starter 44 are stopped. Moreover, the operation | movement of the drive load driven according to driver's operation among the electric loads 45 is stopped. The control device including the ECU 30 is in a power saving state and periodically monitors the state of the vehicle. More specifically, the vehicle parking state is a state in which the ignition switch of the vehicle is turned off.

  The control device 20 turns off both the MOS switch 15 and the SMR switch 16 after flowing the charge / discharge current I between the lithium ion storage battery 10 and the lead storage battery 41. By turning off the switches 15 and 16, the connection between the lithium ion storage battery 10 and the lead storage battery 41 is cut off, and the charge / discharge current I is stopped between the lithium ion storage battery 10 and the lead storage battery 41.

  Thus, the control apparatus 20 changes the charging / discharging current I which flows into the lithium ion storage battery 10 by switching the ON / OFF state of the switches 15 and 16. And the charging / discharging current of the lithium ion storage battery 10 before and after the current change and the detected value of the inter-terminal voltage V are acquired in time series, and based on the detected value V (t), the above circuit constants Rs, R1, Learning of R2, C1, and C2 is performed.

  As shown in FIG. 4, the lithium ion storage battery 10 has a larger change amount of the open-circuit voltage with respect to the change of the SOC than the lead storage battery 41. Therefore, even if the SOCs of the lithium ion storage battery 10 and the lead storage battery 41 are substantially equal, if the SOC is high, the open-circuit voltage of the lithium ion storage battery 10 is high, and if the SOC is low, The open end voltage of the ion storage battery 10 is lowered.

  Moreover, the use area | region is defined about the lithium ion storage battery 10, and when SOC exceeds the upper limit of a use area (overcharge state), or when it falls below the lower limit of a use area (overdischarge state), There is a concern that the deterioration of the lithium ion storage battery 10 is accelerated.

  When the control device 20 turns on the switches 15 and 16 in the parking state of the vehicle, the charge moves from the lithium ion storage battery 10 to the lead storage battery 41 when the lithium ion storage battery 10 is overcharged. When the lithium ion storage battery 10 is excessively discharged, the charge moves from the lead storage battery 41 to the lithium ion storage battery 10. The SOC of the lithium ion storage battery 10 is used while learning the circuit constants Rs, R1, R2, C1, and C2 of the equivalent circuit of the lithium ion storage battery 10 based on the detected value of the inter-terminal voltage V during the charge transfer. It can be within the area. Here, since regenerative power generation is often performed before the vehicle is parked, it is assumed that the SOC of the lithium ion storage battery 10 is close to the upper limit value of the SOC usage region when the vehicle is parked.

  FIG. 5 shows a timing chart representing the switch operation processing. This switch operation process is performed by the control device 20 at predetermined intervals.

  In step S01, it is determined whether or not the vehicle is parked. If the vehicle is not parked (S01: NO), the process is terminated. When the vehicle is in a parked state (S01: YES), in step S02, the detected values of the terminal voltage V and the charge / discharge current I of the lithium ion storage battery 10 are acquired, and the acquired values are stored in time series. Next, in step S03, it is determined whether the standby time has elapsed. Here, the standby time starts from the time when the vehicle is parked, and is provided in order to eliminate the polarization associated with charging / discharging of the lithium ion storage battery 10 associated with traveling of the vehicle. If the standby time has not elapsed (S03: NO), the switches 15 and 16 are turned off in step S04, and the process is terminated. When the switches 15 and 16 are already in the off state, the off state is continued.

  When the standby time has elapsed (S03: YES), in step S05, the SOC is calculated based on the detected values of the inter-terminal voltage V and the charge / discharge current I of the lithium ion storage battery 10 acquired in step S02. . Here, at the time when the standby time has elapsed (immediately before the switches 15 and 16 are turned on), the voltage V between the terminals of the lithium ion storage battery 10 can be acquired as an open-ended voltage that is not affected by polarization. Therefore, the detected value of the inter-terminal voltage V of the lithium ion storage battery 10 immediately before the switches 15 and 16 are turned on is acquired, and the SOC is calculated based on the detected value. Specifically, the control device 20 has a map that associates the open-circuit voltage with the SOC, and calculates the SOC using the map.

  In step S06, it is determined whether or not the state of the power supply system is not a polarization relaxation state (circuit constant calculation period). When the polarization is not relaxed (S06: YES), in step S07, the difference ΔV = | V−Vp | between the terminal voltage V of the lithium ion storage battery 10 and the terminal voltage Vp of the lead storage battery 41 is larger than a predetermined threshold Th1. It is determined whether or not. When the difference ΔV is equal to or smaller than the threshold Th1 (S07: NO), the operation of the battery unit U including the control device 20 is stopped in step S08, and the process is terminated.

  When the difference ΔV is larger than Th1 (S07: YES), the switches 15 and 16 are turned on in step S09. When the switches 15 and 16 are already in the on state, the on state is continued. In step S10, it is determined whether the charging / discharging current I of the lithium ion storage battery 10 is a substantially constant value (constant current) over a predetermined period. Here, the determination as to whether or not the charge / discharge current I is maintained at a substantially constant value over a predetermined period is made based on whether or not the width of the change in the charge / discharge current I during the predetermined period is within a predetermined value. If the charge / discharge current I has not maintained a substantially constant value over a predetermined period (S10: NO), the process is terminated.

  When the charge / discharge current I is maintained at a constant current for a predetermined period (S10: YES), the switches 15 and 16 are turned off in step S11. In step S12, the state of the power supply system is set to the polarization relaxation state (circuit constant calculation period), and the process ends.

  When the state of the power supply system is a polarization relaxation state (S06: NO), it is determined in step S13 whether or not the current lithium ion storage battery 10 is in a steady state based on the detected value of the inter-terminal voltage V. . Specifically, when the difference between the previous value and the current value of the detected value of the inter-terminal voltage V is within a predetermined value, it is determined that the lithium ion storage battery 10 is in a steady state. If it is not a steady state (S13: NO), the process is terminated.

  If it is determined that the current state is a steady state (S13: YES), calculation of each circuit constant constituting the internal resistance 11 is performed in step S14. Specifically, as described above, the voltage change Vt (t) is calculated from the detected value V (t) of the inter-terminal voltage stored in time series in step S02. Vs and V1 are calculated by fitting the voltage change Vt (t) calculated in time series to Equation (3), and learning values of the circuit constants Rs, R1 and C1 are calculated using the calculated values. Further, V2 is calculated by fitting the voltage change Vt (t) calculated in time series to the equation (4), and the learning value of the circuit constants R2 and C2 is calculated using the calculated value.

  In step S15, the calculated value of the circuit constant calculated in step S14 is compared with the previously learned value, and whether or not the calculated value is learned based on the difference between the calculated value and the learned value. Determine whether. Specifically, it is determined that learning is possible when the difference between the calculated value of the circuit constant calculated in step S14 and the previously learned learning value is within a predetermined value. If it is determined that learning is possible (S15: YES), the calculated value of the circuit constant is learned in step S16. Here, the learning value of the circuit constant is stored in association with the SOC calculated in step S05. If it is determined in step S15 that learning is not possible (S15: NO), or after the process of step S16, the polarization relaxation state is canceled in step S17, and the process ends.

  Steps S04, S09, and S11 correspond to “switch operation unit”, steps S14 to 16 correspond to “learning unit”, step S05 corresponds to “charge rate calculation unit”, and step S02. Corresponds to an “acquisition unit”.

  The timing chart showing the change of the charging / discharging current I of the lithium ion storage battery 10 at the time of implementing control of this embodiment in FIG. 6 is shown. At time t10, the vehicle is stopped and the switches 15 and 16 are turned off. Thereafter, at time t <b> 11 after the predetermined standby time has elapsed, the switches 15 and 16 are turned on, and the charge / discharge current I flows through the lithium ion storage battery 10. Thereafter, at time t3, during the period from time t12 to time t13 between times t11 and t13, it is determined that charge / discharge current I is substantially constant at current Ia. Accordingly, at time t13, the switches 15 and 16 are turned off. Thereafter, it is determined that the polarization has relaxed, and the charge / discharge current I is stopped until time t14 when the circuit constant calculation process is performed. After the time t14, when the difference ΔV is equal to or greater than Th1, the switches 15 and 16 are turned on again.

  When the constant current Ia flows through the lithium ion storage battery 10 from time t12 to time t13, the capacity components C1 and C2 are saturated. After that, at time t13, the charge / discharge current I flowing through the lithium ion storage battery 10 is stopped, so that the polarization relaxation state in which the charges accumulated in the capacity components C1 and C2 are discharged. The resistance components Rs, R1, R2, and the capacitance components C1, C2 can be calculated based on the time change of the inter-terminal voltage V from time t13 to time t14.

  The effects of this embodiment will be described below.

  In the parking state, the switches 15 and 16 are turned on to pass a current between the lithium ion storage battery 10 and the lead storage battery 41, and then the switch is turned off to switch the lithium ion storage battery 10 and the lead storage battery 41 between It was set as the structure which stops the electric current between. Since the value of the charging / discharging current I changes in the lithium ion storage battery 10, the capacitance components C1, C2 of the internal resistor 11 are based on the detected value of the charging / discharging current I and the detected value of the inter-terminal voltage V before and after the change. It is possible to calculate learning values of the resistance components Rs, R1, and R2. In this configuration, since the lithium ion storage battery 10 and the lead storage battery 41 are both mounted on the vehicle, the capacity component C1, which constitutes an equivalent circuit of the internal resistance 11, without charging / discharging the in-vehicle power supply system from an external power source. It becomes possible to learn the value of C2 or the resistance components Rs, R1, and R2.

  Further, since various electric loads mounted on the vehicle, for example, the rotating electric machine 40 and the starter 44 are stopped in the parked state, the current value of the charging / discharging current I becomes stable. Further, since the driving of the various electric loads is stopped, radiation noise accompanying the driving of the various electric loads can be suppressed. Therefore, the capacitance components C1, C2 or the resistance components Rs, R1, R2 constituting the equivalent circuit of the internal resistance 11 The adverse effect on the learning value can be suppressed.

  When the switches 15 and 16 (especially the SMR switch 16) are turned off, charging / discharging of the lithium ion storage battery 10 is stopped. That is, the charge / discharge current I of the lithium ion storage battery 10 becomes 0, and the charges accumulated in the capacity components C1 and C2 of the internal resistance 11 of the lithium ion storage battery 10 are stably discharged. For this reason, it becomes possible to improve the accuracy of the learning values of the capacitance components C1, C2 and the resistance components Rs, R1, R2.

  When a constant current flows through the lithium ion storage battery 10 for a predetermined time, the capacity components C1 and C2 of the internal resistance 11 of the lithium ion storage battery 10 are saturated. This makes it possible to accurately acquire the voltage change Vt (t) accompanying the change in the current flowing through the lithium ion storage battery 10 and improve the accuracy of the learned values of the capacity components C1, C2 and the resistance components Rs, R1, R2. It becomes possible to make it.

  By providing a standby time before learning of the capacitance components C1, C2 and the resistance components Rs, R1, R2, the influence of polarization due to charging / discharging of the lithium ion storage battery 10 during traveling of the vehicle is eliminated. Thereby, it becomes possible to improve the accuracy of the learned values of the resistance components Rs, R1, R2 and the capacitance components C1, C2.

  The SOC, the resistance components R1 and R2, and the capacitance components C1 and C2 have a predetermined relationship. For example, the deterioration state of the lithium ion storage battery 10 can be estimated based on the relationship between the SOC, the resistance components R1 and R2, and the capacity components C1 and C2. Therefore, the control device 20 of the present embodiment stores the SOC, the resistance components R1 and R2, and the capacitance components C1 and C2 in association with each other. In this embodiment, the standby time is provided before learning of the capacity components C1 and C2 and the resistance components R1 and R2, thereby eliminating the influence of polarization due to charging and discharging of the lithium ion storage battery 10 while the vehicle is running. By removing the influence of polarization, the SOC can be accurately calculated from the open-circuit voltage of the lithium ion storage battery 10.

  The accuracy of the learned value can be improved by performing the learning of the capacity components C1 and C2 and the resistance components Rs, R1 and R2 a plurality of times in one parking period. Further, by learning the capacitance components C1, C2 and the resistance components Rs, R1, R2 a plurality of times, the voltage V between terminals of the lithium ion storage battery 10 (open-end voltage) and the voltage Vp between terminals of the lead storage battery 41 ( The difference from the open-circuit voltage) decreases. Thereby, SOC of the lithium ion storage battery 10 becomes in the use region, and it is possible to suppress the deterioration of the lithium ion storage battery 10 due to overdischarge or overcharge.

  When the voltage difference ΔV between the lithium ion storage battery 10 and the lead storage battery 41 is equal to or greater than a predetermined value, learning of the resistance components Rs, R1, R2 and the capacitance components C1, C2 is performed. Since the voltage difference ΔV between the lithium ion storage battery 10 and the lead storage battery 41 is equal to or greater than a predetermined value, the current flowing between the lithium ion storage battery 10 and the lead storage battery 41 when the switch is turned on is equal to or greater than the predetermined value. For this reason, since the current change when the switches 15 and 16 are changed from the ON state to the OFF state becomes a predetermined value or more, the change amount Vt of the inter-terminal voltage V accompanying the relaxation of the polarization becomes a predetermined value or more. For this reason, it becomes possible to learn the resistance components Rs, R1, R2 and the capacitance components C1, C2 with high accuracy.

  If the calculated value is significantly different from the previous learned value, it is determined that an abnormality has occurred in the calculation of the circuit constants (resistance components Rs, R1, R2 and capacitance components C1, C2), and the current calculated value is learned. Not configured. By adopting such a configuration, it is possible to suppress learning of an abnormal value and improve the accuracy of the learned value.

(Other embodiments)
A configuration in which one of the MOS switch 15 and the SMR switch 16 is omitted may be employed.

  In the configuration in which the SMR switch 16 is omitted, an electric load may be connected to the lithium ion storage battery 10 side from the MOS switch 15. Furthermore, in a parking state, the structure which a dark current flows with respect to the electric load by the side of the lithium ion storage battery 10 from the lithium ion storage battery 10 may be sufficient. Even with such a configuration, the charging / discharging current I of the lithium ion storage battery 10 changes as the ON / OFF state of the MOS switch 15 changes. Therefore, it is possible to calculate the circuit constant based on the current change. It is.

  An equivalent circuit model having only the first reaction resistance may be used as the internal resistance of the lithium ion storage battery 10.

  -It is good also as a structure which abbreviate | omits the process of step S03 of FIG. That is, immediately after the vehicle is parked, the switches 15 and 16 may be turned on so that a current flows between the lithium ion storage battery 10 and the lead storage battery 41.

  -In step S13 of FIG. 5, based on the detected value of the voltage V between terminals, determination whether the present lithium ion storage battery 10 was a steady state was implemented. It is good also as a structure which changes this and determines that the lithium ion storage battery 10 is a steady state, when predetermined time passes since the state of a power supply system was set to the polarization relaxation state. Here, the predetermined time may be set to a time sufficiently larger than the larger one (τ2) of the time constants τ1, τ2 of the internal resistance of the lithium ion storage battery 10.

  In Steps S10 to S12 in FIG. 5, when the charging / discharging current I is a constant current over a predetermined time, the switches 15 and 16 are turned off and the power supply system is set in the polarization relaxation state. By changing this, when a predetermined time elapses after the switches 15 and 16 are turned on, the switches 15 and 16 may be turned off to set the power supply system in the polarization relaxation state. In such a configuration, the voltages V1 and V2 of the parallel circuits P1 and P2 at the time when the switches 15 and 16 are turned off are estimated based on the detected value of the charge / discharge current I, and the estimated values are calculated. It is preferable that the circuit constants are calculated by using them.

  The learning process is repeated until the difference ΔV between the inter-terminal voltage V of the lithium ion storage battery 10 and the inter-terminal voltage Vp of the lead storage battery 41 is less than a predetermined value, but this is changed and the vehicle is parked. In this case, the learning process may be performed only once.

  -About the storage battery used as the calculation object of a circuit constant, you may be other than a lithium ion storage battery. For example, a lead storage battery or a nickel hydride storage battery may be used. Here, in charge / discharge control of a lithium ion storage battery and a nickel metal hydride storage battery, it is necessary to accurately acquire the SOC in order to suppress overcharge and overdischarge. For this reason, when the structure of the said embodiment is applied with respect to a lithium ion storage battery and a nickel hydride storage battery, it becomes possible to perform suitable charging / discharging control.

  DESCRIPTION OF SYMBOLS 10 ... Lithium ion storage battery, 11 ... Internal resistance, 15 ... MOS switch, 16 ... SMR switch, 20 ... Control apparatus, 25 ... Current sensor, 26 ... Voltage sensor, 41 ... Lead storage battery, C1, C2 ... Capacity component, P1, P2: Parallel circuit, R1, R2: Resistance component.

Claims (14)

On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Based on the charging / discharging current before and during the change of the current flowing between the first storage battery and the second storage battery accompanying the switching of the on / off state of the switch , and the detected value of the voltage between the terminals, And a learning unit that calculates a value of the resistance component or the capacitance component and learns the calculated value as a learning value. The switch operating unit is in a state in which a current flows between the first storage battery and the second storage battery by operating the switch to an on state, and the charge / discharge current is a substantially constant value over a predetermined time. control device according to claim 1, characterized in that operating in the oFF state the switch from the oN state when. On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Learning to calculate the value of the resistance component or the capacitance component based on the charge / discharge current in the ON state and the OFF state of the switch and the detected value of the voltage between the terminals, and to learn the calculated value as a learning value And
The switch operating unit is in a state in which a current flows between the first storage battery and the second storage battery by operating the switch to an on state, and the charge / discharge current is a substantially constant value over a predetermined time. In some cases, the control device operates the switch from an on state to an off state.   The switch operation unit operates the switch to an off state when the vehicle is in a parked state, and operates the switch from an off state to an on state when a standby time has elapsed, thereby allowing the first storage battery to operate. 4. The control device according to claim 1, wherein a current is passed between the second storage battery and the second storage battery. 5. On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Learning to calculate the value of the resistance component or the capacitance component based on the charge / discharge current in the ON state and the OFF state of the switch and the detected value of the voltage between the terminals, and to learn the calculated value as a learning value And
The switch operation unit operates the switch to an off state when the vehicle is in a parked state, and operates the switch from an off state to an on state when a standby time has elapsed, thereby allowing the first storage battery to operate. And a control device, wherein a current is passed between the second storage battery and the second storage battery. The control device includes a charging rate calculation unit that calculates a charging rate of the first storage battery from a detected value of the voltage between the terminals immediately before the standby time has elapsed and the switch is turned on.
The learning unit, the control device according to claim 4 or 5, characterized in that learning in association with the learning value of the said charge rate resistance component or the capacitance component. The acquisition unit acquires a detection value of a voltage between terminals of the second storage battery from a voltage detection unit,
Calculation of the value of the resistance component or the capacity component by the learning unit until the difference between the detected value of the inter-terminal voltage of the first storage battery and the detected value of the inter-terminal voltage of the second storage battery is less than a predetermined value. control device according to any one of claims 1 to 6, characterized in that repeated. On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Learning to calculate the value of the resistance component or the capacitance component based on the charge / discharge current in the ON state and the OFF state of the switch and the detected value of the voltage between the terminals, and to learn the calculated value as a learning value And
The acquisition unit acquires a detection value of a voltage between terminals of the second storage battery from a voltage detection unit,
Calculation of the value of the resistance component or the capacity component by the learning unit until the difference between the detected value of the inter-terminal voltage of the first storage battery and the detected value of the inter-terminal voltage of the second storage battery is less than a predetermined value. The control apparatus characterized by repeating. The acquisition unit acquires a detection value of a voltage between terminals of the second storage battery from a voltage detection unit,
In the switch operation unit, the vehicle is in a parked state, and the difference between the detected value of the inter-terminal voltage of the first storage battery and the detected value of the inter-terminal voltage of the second storage battery is a predetermined value or more. , the control according to any one of claims 1 to 8, characterized in that a current flows between the first battery and the second battery by operating the switch from the oFF state to the oN state apparatus. On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Learning to calculate the value of the resistance component or the capacitance component based on the charge / discharge current in the ON state and the OFF state of the switch and the detected value of the voltage between the terminals, and to learn the calculated value as a learning value And
The acquisition unit acquires a detection value of a voltage between terminals of the second storage battery from a voltage detection unit,
In the switch operation unit, the vehicle is in a parked state, and the difference between the detected value of the inter-terminal voltage of the first storage battery and the detected value of the inter-terminal voltage of the second storage battery is a predetermined value or more. In addition, a control device is characterized in that a current flows between the first storage battery and the second storage battery by operating the switch from an OFF state to an ON state. The learning unit compares the calculated value of the resistance component or the capacitance component with a previously learned value, and determines whether to learn the calculated value based on a difference between the calculated value and the learned value. control device according to any one of claims 1 to 10, wherein the determining. On-board power supply mounted on a vehicle, comprising a first storage battery (10), a second storage battery (41), and switches (15, 16) provided between the first storage battery and the second storage battery A power supply system control device (20) for controlling the system,
The equivalent circuit of the internal resistance (11) of the first storage battery has a parallel circuit (P1, P2) of a resistance component (R1, R2) and a capacity component (C1, C2),
An acquisition unit that acquires a detection value of a charge / discharge current flowing in the first storage battery from a current detection unit (25), and acquires a detection value of a voltage between terminals of the first storage battery from a voltage detection unit (26);
When the vehicle is in a parked state, by operating the switch to an on state, a current is passed between the first storage battery and the second storage battery, and then the switch is operated from an on state to an off state. A switch operation unit for stopping the current flowing between the first storage battery and the second storage battery,
Learning to calculate the value of the resistance component or the capacitance component based on the charge / discharge current in the ON state and the OFF state of the switch and the detected value of the voltage between the terminals, and to learn the calculated value as a learning value And
The learning unit compares the calculated value of the resistance component or the capacitance component with a previously learned value, and determines whether to learn the calculated value based on a difference between the calculated value and the learned value. A control device characterized by determining. Wherein the first storage battery, when the switch is turned off, the control device according to any one of claims 1 to 12 charge and discharge is characterized in that to be stopped. Wherein the first battery is a lithium ion battery, or control device according to any one of claims 1 to 13, characterized in that the nickel-hydrogen storage battery.