JPWO2016002135A1 - Lead storage battery deterioration determination device, lead storage battery deterioration determination method, charge control device, and charge control method - Google Patents

Abstract

A lead-acid battery degradation determination device according to the present disclosure includes a lead-acid battery connected in parallel to each other and a secondary battery other than the lead-acid battery, a voltage detection part that detects the voltage of the power-supply part, and the interior of the secondary battery An acquisition unit for acquiring resistance, a storage unit for preliminarily storing an entire current value supplied from the power source unit to the starting motor when the engine is started by the starting motor, and a voltage of the power source unit when the engine is started by the starting motor Using the starting voltage, the internal resistance of the secondary battery, and the overall current value, the calculation unit that calculates the internal resistance of the lead storage battery is compared with the calculated internal resistance of the lead storage battery and a predetermined resistance threshold value. And when the internal resistance of a lead storage battery is higher than a resistance threshold value, the determination part which determines with a lead storage battery having deteriorated is provided.

Description

  The present disclosure relates to a deterioration determination device for a lead storage battery and a deterioration determination method for a lead storage battery that determine whether or not the lead storage battery is deteriorated, a charge control device that charges a lead storage battery and a secondary battery connected in parallel to each other, and charging Control method.

  A vehicle having an engine as a main power source includes a battery as a power source of a starter motor for starting the engine. As the battery, a lead storage battery is generally used.

  In recent years, a battery is charged with electric power generated by a generator using energy generated when the vehicle starts to decelerate by braking while traveling (energy regeneration). However, when energy is regenerated, rapid charging is performed. However, since lead-acid batteries cannot perform sufficient rapid charging, it is difficult to effectively regenerate energy.

  Therefore, a vehicle including a power source unit in which a secondary battery other than a lead storage battery such as a nickel metal hydride secondary battery or a lithium ion secondary battery capable of sufficient rapid charging is connected in parallel with the lead storage battery is known (Patent Literature). 1).

  However, in Patent Document 1, further improvement has been desired.

JP 2012-90404 A

  In order to solve the above-described problem, a first aspect of the present invention is a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery that are connected in parallel to each other, and a voltage detection that detects a voltage of the power supply unit. An acquisition unit that acquires an internal resistance of the secondary battery, a storage unit that stores in advance a total current value supplied from the power supply unit to the starter motor when the engine is started by the starter motor, and the starter A starting voltage which is a voltage of the power source when the engine is started by the motor for motor is detected by the voltage detector, the detected starting voltage, and an internal resistance of the secondary battery acquired by the acquiring unit; A calculation unit that calculates an internal resistance of the lead storage battery using the overall current value stored in the storage unit; an internal resistance of the lead storage battery calculated by the calculation unit; and a predetermined resistance threshold value And the ratio To, when the internal resistance of the lead-acid battery is higher than the threshold resistance value, the lead-acid battery in which and a determination unit to be deteriorated.

  According to this aspect, further improvement can be achieved.

1 is a block diagram schematically showing a configuration of a vehicle including a battery control unit according to a first embodiment. It is a figure which shows schematically the transition of the voltage of a power supply part. It is a figure which shows the equivalent circuit of ISG, lead acid battery, and nickel metal hydride battery. It is a flowchart which shows roughly operation | movement of a battery control part. It is a figure which shows roughly change of internal resistance of the lead storage battery and nickel hydride storage battery which are used for a vehicle. It is a block diagram which shows roughly the structure of the vehicle containing the battery control part and ECU of 2nd Embodiment. It is a figure which shows roughly an example of the table showing the relationship between the threshold value of the lead acid battery 50, and the SOC value of the nickel hydride storage battery at the time of charge start. 7 is a timing chart schematically showing a charging current when the power supply unit of FIG. 6 is charged at a constant voltage of 13.7V. It is a flowchart which shows the charge operation of 2nd Embodiment schematically. It is a figure which shows roughly an example of SOC of the lead storage battery and nickel hydride storage battery which increase by the charging operation of FIG. It is a flowchart which shows roughly the charge operation of 3rd Embodiment. It is a figure which shows roughly an example of SOC of the lead storage battery and nickel hydride storage battery which increase by the charging operation of FIG. 3 is a timing chart schematically showing the operation of a switch element. It is a timing chart which shows the output voltage of ISG schematically. It is a block diagram which shows roughly the structure of the vehicle containing the battery control part and ECU of 4th Embodiment. It is a flowchart which shows schematically the charge operation of 4th Embodiment. It is a figure which shows roughly an example of SOC of the lead storage battery and nickel hydride storage battery which increase by the charging operation of FIG. 3 is a timing chart schematically showing the operation of a switch element. It is a flowchart which shows roughly the charging operation of 5th Embodiment. It is a flowchart which shows roughly the charging operation of 5th Embodiment. It is a block diagram which shows roughly the structure of the vehicle containing the battery control part and ECU of 6th Embodiment. 16 is a timing chart schematically showing a charging current when the power supply unit of FIG. 15 is charged at a constant voltage of 13.7V. It is a timing chart which shows the output voltage of ISG schematically. It is a timing chart which shows roughly the charging current when carrying out the constant voltage charge of the power supply part comprised by mutually connecting a lead storage battery and a nickel metal hydride storage battery in parallel.

(Background to inventing the first aspect of the present disclosure)
First, the focus of the first aspect according to the present disclosure will be described.

  According to a first aspect of the present disclosure, in a configuration including a power source unit in which a secondary battery other than a lead storage battery is connected in parallel with the lead storage battery, the deterioration determination device for the lead storage battery and the lead capable of accurately determining the deterioration of the lead storage battery It aims at providing the deterioration determination method of a storage battery.

  In recent years, vehicles having an idle stop function are becoming popular in order to reduce exhaust gas from vehicles using an engine as a main power source. In a vehicle having an energy regeneration function as described above and an idle stop function, the lead storage battery is frequently charged and discharged. For this reason, we are anxious about deterioration of a lead storage battery. However, in the said patent document 1, it is not fully examined about determining whether the lead acid battery has deteriorated.

  Therefore, the present inventor has a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery (nickel metal hydride storage battery in the present embodiment) connected in parallel to each other as in the technique described in Patent Document 1. We examined the deterioration of lead-acid batteries when used in vehicles. As the battery deteriorates, the internal resistance of the battery increases.

  FIG. 5 is a diagram schematically showing changes in internal resistance between a lead storage battery and a nickel hydride storage battery used in a vehicle. The upper diagram in FIG. 5 shows changes in individual internal resistances of the lead storage battery and the nickel metal hydride storage battery. The lower diagram of FIG. 5 shows the transition of the combined internal resistance in which the internal resistances of the lead storage battery and the nickel metal hydride storage battery are combined.

  Lead acid batteries used in vehicles are generally replaced in three years. Therefore, as shown in the upper diagram of FIG. 5, the internal resistance Rpb of the lead-acid battery continues to increase for three years from the initial value Rpb0, but returns to the initial value Rpb0 for every replacement after three years. On the other hand, nickel-metal hydride storage batteries are designed with a lifespan of 9 years or more, similar to vehicles. Therefore, as shown in the upper diagram of FIG. 5, the internal resistance Rni of the nickel metal hydride storage battery continues to increase for nine years from the initial value Rni0.

  As a result, the combined internal resistance Rt of the lead storage battery and the nickel hydride storage battery continues to increase for three years from the initial value R0, and then decreases due to replacement of the lead storage battery after three years. However, since the internal resistance of the nickel metal hydride storage battery is increasing, the combined internal resistance Rt is reduced only to a resistance value R3 higher than the initial value R0. Similarly, even after six years, the combined internal resistance Rt decreases due to replacement of the lead storage battery, but only decreases to a resistance value R6 higher than the resistance value R3.

  Therefore, if the deterioration determination of the lead storage battery is performed by comparing the predetermined resistance threshold Rd with the combined internal resistance Rt, it can be determined that the deterioration has occurred at an appropriate timing after three years from the start of use of the vehicle. However, after replacement of the lead storage battery, the combined internal resistance Rt reaches the resistance threshold value Rd in Td year (3 <Td <6) from the start of use of the vehicle. For this reason, within 3 years from the replacement of the lead storage battery, it is determined that the lead storage battery has deteriorated even though it has not deteriorated. Therefore, it is necessary to determine the deterioration of the lead storage battery not by the combined internal resistance Rt but by the internal resistance Rpb of the lead storage battery alone.

  Therefore, it is conceivable to provide a current sensor that detects the current flowing in the lead storage battery and a voltage sensor that detects the terminal voltage of the lead storage battery, and calculate the internal resistance of the lead storage battery from the detected current and the terminal voltage. However, since a large current flows when the engine is started, an expensive and large current sensor is required to detect such a large current, resulting in an increase in cost and installation space.

  Based on the above examination, the present inventor has come up with the invention of each aspect included in the first aspect according to the present disclosure as follows.

  A first aspect according to the present disclosure includes a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel to each other, a voltage detection unit that detects a voltage of the power supply unit, and the secondary battery An acquisition unit for acquiring the internal resistance of the engine, a storage unit for preliminarily storing an entire current value supplied from the power supply unit to the starting motor when the engine is started by the starting motor, and starting the engine by the starting motor The starting voltage which is the voltage of the power supply unit at the time is detected by the voltage detecting unit, the detected starting voltage, the internal resistance of the secondary battery acquired by the acquiring unit, and stored in the storage unit The total current value is used to calculate the internal resistance of the lead storage battery, and the internal resistance of the lead storage battery calculated by the calculation section is compared with a predetermined resistance threshold value. Lead acid battery If the internal resistance is higher than the threshold resistance value, the lead-acid battery in which comprises a a determination unit has deteriorated, the.

  According to this aspect, the starting voltage which is the voltage of the power source when the engine is started by the starting motor is detected by the voltage detector. Using the detected starting voltage, the internal resistance of the secondary battery, and the total current value supplied to the starting motor from the power source when the engine is started by the starting motor, the internal resistance of the lead storage battery is Calculated. The total current value supplied from the power supply unit to the starting motor when the engine is started by the starting motor depends on the specifications of the starting motor and the engine. Therefore, when the starting motor and engine are determined, the overall current value is also determined. Therefore, the entire current value can be stored in the storage unit in advance.

  First, the combined internal resistance of the secondary battery and the lead storage battery connected in parallel with each other is calculated using the total current value stored in the storage unit and the detected starting voltage. Next, the internal resistance of the lead storage battery is calculated from the calculated combined internal resistance and the acquired internal resistance of the secondary battery. When the internal resistance of the lead storage battery is higher than the resistance threshold, the determination unit determines that the lead storage battery has deteriorated. Therefore, the deterioration of the lead storage battery can be accurately determined using the internal resistance of the lead storage battery alone.

  In the first aspect, for example, when the determination unit determines that the lead storage battery is deteriorated, the engine may be prohibited from being automatically stopped by idle stop control.

  According to this aspect, when the determination unit determines that the lead storage battery has deteriorated, the determination unit prohibits the automatic stop of the engine by the idle stop control. Therefore, it is possible to avoid a situation in which the engine that is automatically stopped cannot be started due to deterioration of the lead storage battery.

  In the first aspect, for example, the starting motor may be a motor that starts the engine that is automatically stopped by the idle stop control.

  In the first aspect, for example, the starting motor may be a motor that starts the engine by an operation of an ignition switch by a user.

  Another aspect according to the present disclosure is a deterioration determination method for a lead storage battery in a deterioration determination apparatus for a lead storage battery including a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel to each other, An acquisition step of acquiring an internal resistance of the secondary battery, a detection step of detecting a starting voltage that is a voltage of the power supply unit when the engine is started by the starting motor, and the starting voltage detected in the detecting step; Using the internal resistance of the secondary battery acquired in the acquisition step and the total current value supplied from the power supply unit to the starter motor when the engine is started by the starter motor, Comparing the calculation step of calculating the internal resistance, the internal resistance of the lead storage battery calculated in the calculation step and a predetermined resistance threshold, If the internal resistance of Kinamari battery is higher than the threshold resistance value, the lead-acid battery is intended to include, a determining step of determining to be deteriorated.

  According to this aspect, the starting voltage detected in the detecting step, the internal resistance of the secondary battery acquired in the acquiring step, and the total current supplied from the power supply unit to the starting motor when the engine is started by the starting motor. The internal resistance of the lead storage battery is calculated in the calculation step using the value. The total current value supplied from the power supply unit to the starting motor when the engine is started by the starting motor depends on the specifications of the starting motor and the engine. Therefore, when the starting motor and engine are determined, the overall current value is also determined. Therefore, a predetermined overall current value can be used.

  First, the combined internal resistance of the secondary battery and the lead storage battery connected in parallel is calculated using the total current value and the detected starting voltage. Next, the internal resistance of the lead storage battery is calculated from the calculated combined internal resistance and the internal resistance of the secondary battery. In the determination step, when the internal resistance of the lead storage battery is higher than the resistance threshold, it is determined that the lead storage battery has deteriorated. Therefore, the deterioration of the lead storage battery can be accurately determined using the internal resistance of the lead storage battery alone.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention. Moreover, in each figure, the same code | symbol is attached | subjected to the same element and description is abbreviate | omitted suitably.

  FIG. 1 is a block diagram schematically showing the configuration of the vehicle 1 including the battery control unit 80 of the first embodiment.

  The vehicle 1 is a hybrid electric vehicle having an engine as a main power source and a motor as an auxiliary power source. The vehicle 1 includes an engine 10, a starter motor 20, an integrated starter generator (ISG) 30, an electrical load 40, a power supply unit 45, an electronic control unit (ECU) 70, and the battery control unit 80 of the first embodiment.

  The power supply unit 45 includes a lead storage battery 50 and a battery pack 60. The battery pack 60 includes a nickel metal hydride storage battery 61 and a resistance detection unit 62. The lead storage battery 50 and the nickel metal hydride storage battery 61 are connected in parallel to each other. The starter motor 20 (an example of a starting motor) starts the engine 10 when the ignition switch is operated by the user.

  The ISG 30 (an example of a starting motor) has both a power generation function and an electric function. When a brake pedal (not shown) is operated while the vehicle 1 is traveling and starts to decelerate, torque is transmitted from the wheels to the ISG 30, and the ISG 30 generates power by the power generation function. When the generated power exceeds the electrical load of the electrical load 40, the lead storage battery 50 and the nickel hydride storage battery 61 of the power supply unit 45 are charged by the generated power. This regenerates energy. When the vehicle 1 stops, the engine 10 is automatically stopped by the idle stop control of the ECU 70. When the vehicle 1 starts, the vehicle 1 is driven by the electric function of the ISG 30 and the engine 10 is started.

  The electrical load 40 includes a load such as an electrical component equipped in the vehicle 1 such as an air conditioner and a room light. The nominal voltages of the lead storage battery 50 and the nickel metal hydride storage battery 61 are, for example, 12V in the first embodiment. The electric power output from the power supply unit 45 is used to drive the starter motor 20 and the ISG 30 that start the engine 10 of the vehicle 1 and to power the electrical load 40.

  The resistance detector 62 of the battery pack 60 detects the internal resistance Rni of the nickel metal hydride storage battery 61. The resistance detection unit 62 includes, for example, a current detection unit including a shunt resistor and a voltage detection unit that detects a terminal voltage of the nickel metal hydride storage battery 61. The resistance detection unit 62 is provided to determine whether or not the nickel metal hydride storage battery 61 is abnormal and to protect the battery pack 60. The resistance detector 62 is configured to output a warning signal to the ECU 70 when detecting that the internal resistance Rni of the nickel metal hydride storage battery 61 is equal to or greater than a predetermined value, for example.

  The ECU 70 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) in which a predetermined control program is stored, a RAM (Random Access Memory) in which data is temporarily stored, these Peripheral circuits are provided. The ECU 70 is configured to be able to communicate with the battery control unit 80.

  The ECU 70 controls the overall operation of the vehicle 1 including the engine 10, starter motor 20, ISG 30, and electrical load 40. The ECU 70 automatically stops the engine 10 when a predetermined stop condition such as the vehicle 1 is stopped for a predetermined time at an intersection or the like, and again when a predetermined start condition such as release of operation of a brake pedal (not shown) is satisfied. Idle stop control for starting the engine 10 is performed. When the prohibition signal (described later) is notified from the battery control unit 80, the ECU 70 does not automatically stop the engine 10 by the idle stop control.

  The battery control unit 80 includes, for example, a CPU that executes predetermined arithmetic processing, a ROM that stores a predetermined control program, a RAM that temporarily stores data, and peripheral circuits thereof. The battery control unit 80 includes a storage unit 81 and a voltage detection unit 82 configured by, for example, a flash memory. The battery control unit 80 functions as the calculation unit 83 and the determination unit 84 by executing a control program stored in the ROM.

  The storage unit 81 stores in advance an overall current value It supplied from the power supply unit 45 to the starter motor 20 or ISG 30 when the starter motor 20 or ISG 30 starts the engine 10. The total current value It depends on the specifications of the engine 10, the starter motor 20, and the ISG 30. Therefore, when engine 10, starter motor 20, and ISG 30 are determined, overall current value It is also determined. In the first embodiment, when the starter motor 20 starts the engine 10, the total current value supplied from the power supply unit 45 to the starter motor 20 and when the ISG 30 starts the engine 10, the power supply unit 45 starts the ISG 30. Is approximately the same value as the total current value supplied to the. The total current value It is, for example, 500A.

  The storage unit 81 stores in advance a resistance threshold value Rth for determining whether or not the lead storage battery 50 is deteriorated. Storage unit 81 stores in advance a voltage threshold value Vth for determining whether or not engine 10 has been started.

  The voltage detector 82 detects the voltage Vt of the power supply unit 45. The voltage detection unit 82 outputs the detected voltage Vt to the calculation unit 83. The calculation unit 83 compares the voltage Vt of the power supply unit 45 detected by the voltage detection unit 82 with the voltage threshold value Vth stored in the storage unit 81, and determines whether the engine 10 is started by the starter motor 20 or the ISG 30. Determine whether or not.

  FIG. 2 is a diagram schematically showing the transition of the voltage Vt of the power supply unit 45. When the engine 10 is started by the starter motor 20 or the ISG 30, a large current (for example, 500A as described above) is supplied from the power supply unit 45 to the starter motor 20 or the ISG 30. For this reason, as shown in FIG. 2, when the engine 10 is started by the starter motor 20 or the ISG 30 at the time T0, the voltage Vt of the power supply unit 45 temporarily temporarily decreases to the minimum voltage Vmin (an example of the starting voltage). And then slowly returns to the original voltage.

  The calculation unit 83 determines that the engine 10 has been started when the voltage Vt of the power supply unit 45 falls below the voltage threshold value Vth stored in the storage unit 81. The calculation unit 83 acquires the minimum voltage Vmin detected by the voltage detection unit 82 from the voltage detection unit 82. The voltage threshold Vth is set to an appropriate value of about 10 V, for example, according to the specifications of the engine 10, the starter motor 20, the ISG 30, and the power supply unit 45, and is stored in the storage unit 81 in advance.

  Returning to FIG. 1, when the calculation unit 83 (an example of an acquisition unit) determines that the engine 10 has been started by the starter motor 20 or the ISG 30, the calculation unit 83 acquires the internal resistance Rni of the nickel-metal hydride storage battery 61 from the resistance detection unit 62. The calculation unit 83 (an example of the calculation unit) includes the minimum voltage Vmin detected by the voltage detection unit 82, the total current value It stored in the storage unit 81, and the nickel hydride storage battery 61 acquired from the resistance detection unit 62. Using the internal resistance Rni, the internal resistance Rpb of the lead storage battery 50 is calculated.

FIG. 3 is a diagram showing an equivalent circuit of the ISG 30, the lead storage battery 50, and the nickel hydride storage battery 61. In the equivalent circuit of FIG. 3, the following equation (1) is established.
Rt = Vmin / It (1)
However, Vmin is the minimum voltage detected by the voltage detection part 82, It is the whole electric current value memorize | stored in the memory | storage part 81, Rt is the synthesis | combination of the lead storage battery 50 and the nickel hydride storage battery 61 connected in parallel. Internal resistance. The combined internal resistance Rt of the lead storage battery 50 and the nickel metal hydride storage battery 61 connected in parallel is calculated by the equation (1).

In the equivalent circuit of FIG. 3, the following equation (2) is established.
1 / Rt = 1 / Rpb + 1 / Rni (2)
However, Rpb is an internal resistance of the lead storage battery 50, and Rni is an internal resistance of the nickel metal hydride storage battery 61.

From the above formulas (1) and (2), the following formula (3) is obtained.
1 / Rpb = It / Vmin−1 / Rni (3)
The internal resistance Rpb of the lead storage battery 50 is calculated by the above formula (3).

  Returning to FIG. 1, the calculation unit 83 outputs the calculated internal resistance Rpb of the lead storage battery 50 to the determination unit 84. The determination unit 84 compares the internal resistance Rpb of the lead storage battery 50 calculated by the calculation unit 83 with the resistance threshold Rth stored in the storage unit 81 to determine whether or not the lead storage battery 50 has deteriorated. To do. That is, the determination unit 84 determines that the lead storage battery 50 has deteriorated if the calculated internal resistance Rpb of the lead storage battery 50 exceeds the resistance threshold Rth. The resistance threshold Rth is set to an appropriate value according to the specifications of the lead storage battery 50 and is stored in the storage unit 81 in advance.

  If the determination part 84 determines with the lead acid battery 50 having deteriorated, it will output the prohibition signal which prohibits idle stop control to ECU70. When the deterioration determination of the lead storage battery 50 continues for a predetermined number of times, the determination unit 84 outputs an exchange signal for prompting the user to replace the lead storage battery 50 to the ECU 70.

  FIG. 4 is a flowchart schematically showing the operation of the battery control unit 80. First, the voltage detection part 82 detects the voltage Vt of the power supply part 45, and outputs it to the calculating part 83 (S1). The computing unit 83 determines whether or not the detected voltage Vt is less than the voltage threshold Vth (S2). If the detected voltage Vt is equal to or higher than the voltage threshold Vth (NO in S2), the process returns to S1. If the detected voltage Vt is less than the voltage threshold Vth (YES in S2), the voltage detection unit 82 detects the minimum voltage Vmin of the power supply unit 45, and the calculation unit 83 obtains the minimum voltage Vmin from the voltage detection unit 82. Obtain (S3, an example of a detection step).

  The calculation unit 83 acquires the internal resistance Rni of the nickel hydride storage battery 61 from the resistance detection unit 62 of the battery pack 60 (S4, an example of an acquisition step). The calculation unit 83 uses the total current value It stored in the storage unit 81, the detected minimum voltage Vmin, and the internal resistance Rni of the nickel-metal hydride storage battery 61 acquired from the resistance detection unit 62, 3), the internal resistance Rpb of the lead storage battery 50 is calculated, and the calculated internal resistance Rpb is output to the determination unit 84 (S5, an example of calculation step).

  The determination unit 84 determines whether or not the calculated internal resistance Rpb of the lead storage battery 50 exceeds the resistance threshold Rth (S6, an example of a determination step). If the internal resistance Rpb of the lead storage battery 50 does not exceed the resistance threshold Rth (NO in S6), the process returns to S1. If the internal resistance Rpb of the lead storage battery 50 exceeds the resistance threshold value Rth (YES in S6), the determination unit 84 notifies the ECU 70 of a prohibition signal for prohibiting the idle stop control (S7).

  The determination unit 84 increments the count value Cdg (S8). The determination unit 84 determines whether or not the count value Cdg exceeds a predetermined threshold value Cth (S9). If the count value Cdg does not exceed the threshold value Cth (NO in S9), the process returns to S1. If the count value Cdg exceeds the threshold Cth (YES in S9), the ECU 70 is notified of an exchange signal for prompting the user to replace the lead storage battery 50 (S10).

  The ECU 70 may prompt the user to replace the lead storage battery 50 by generating sound, displaying characters, or lighting a replacement LED.

  As described above, the battery pack 60 of the first embodiment includes the resistance detection unit 62 that detects the internal resistance Rni of the nickel metal hydride storage battery 61 in order to protect the nickel metal hydride storage battery 61. Therefore, the battery control unit 80 of the first embodiment uses the internal resistance Rni of the nickel hydride storage battery 61 detected by the existing resistance detection unit 62.

  Further, the total current value It supplied from the power supply unit 45 to the starter motor 20 or the ISG 30 when the engine 10 is started depends on the specifications of the engine 10, the starter motor 20, and the ISG 30. Therefore, when the engine 10, the starter motor 20, and the ISG 30 are determined, the overall current value It is also determined.

  Therefore, the battery control unit 80 of the first embodiment calculates the internal resistance Rpb of the lead storage battery 50 using these. Therefore, the internal resistance Rpb of the lead storage battery 50 can be obtained with a simple configuration without providing a large current sensor that detects the current flowing only in the lead storage battery 50. As a result, according to the first embodiment, it can be accurately determined whether or not the lead storage battery 50 is deteriorated.

  In the first embodiment, the internal resistance Rpb is calculated using the minimum voltage Vmin of the power supply unit 45 when the engine 10 is started (that is, when a large current of 500 A flows, for example). For example, when the engine 10 is stopped by idle stop control, a current of 10 to 20 A is supplied from the power supply unit 45 to the electrical load 40. In this case, since the current is small, the difference between the normal voltage of the power supply unit 45 and the minimum voltage Vmin is small. For this reason, the difference between the minimum voltage Vmin when the lead storage battery 50 is normal and the minimum voltage Vmin when the lead storage battery 50 is deteriorated becomes small.

  On the other hand, when a large current is supplied from the power supply unit 45, the difference between the normal voltage of the power supply unit 45 and the minimum voltage Vmin is large. For this reason, the difference between the minimum voltage Vmin when the lead storage battery 50 is normal and the minimum voltage Vmin when the lead storage battery 50 is deteriorated increases. As a result, according to the first embodiment, it can be accurately determined whether or not the lead storage battery 50 is deteriorated.

(Modification of the first embodiment)
The present invention is not limited to the first embodiment. Hereinafter, modifications of the first embodiment of the present invention will be described.

  (1) In the first embodiment, the calculation unit 83 of the battery control unit 80 starts the engine 10 by the starter motor 20 or the ISG 30 depending on whether or not the voltage Vt of the power supply unit 45 has dropped below the voltage threshold Vth. It is determined whether or not. Alternatively, the ECU 70 may be configured to notify the battery control unit 80 that the engine 10 has been started. In this case, the calculation unit 83 may acquire the minimum voltage Vmin from the voltage detection unit 82 when receiving a notification from the ECU 70 that the engine 10 has been started.

  (2) In the first embodiment, the vehicle 1 includes the battery control unit 80 separately from the ECU 70. Alternatively, the ECU 70 may be configured to include each functional block of the battery control unit 80, and the battery control unit 80 may be omitted. In this case, the ECU 70 may acquire the minimum voltage Vmin detected by the voltage detection unit 82 when controlling the start of the engine 10.

  (3) In the first embodiment, the battery pack 60 includes the nickel hydride storage battery 61. Alternatively, the battery pack 60 may include other secondary batteries such as a lithium ion secondary battery, a lithium ion polymer secondary battery, and a nickel zinc storage battery.

  (4) In the said 1st Embodiment, the starter motor 20 which starts the engine 10 by operation of the ignition switch by a user is provided. Alternatively, the starter motor 20 may be eliminated, and the ISG 30 may start the engine 10 by operating the ignition switch by the user.

  (5) In the first embodiment, the ECU 70 obtains the minimum voltage Vmin of the power supply unit 45 from the voltage detection unit 82 when the engine 10 is started by the starter motor 20 or the ISG 30, and the minimum voltage Vmin is obtained in advance. If it is less than a predetermined threshold value, automatic stop of the engine 10 by idle stop control may be prohibited. In this case, the ECU 70 may set different threshold values for when the engine 10 is started by the starter motor 20 and when the engine 10 is started by the ISG 30.

(Background to inventing the second aspect of the present disclosure)
First, the focus of the second aspect according to the present disclosure will be described.

  The second aspect of the present disclosure provides a charge control device and a charge control in which both the lead storage battery and the secondary battery are not insufficiently charged with a simple configuration when charging the lead storage battery and the secondary battery connected in parallel with each other. It aims to provide a method.

  In the vehicle described in Patent Document 1, the secondary battery other than the lead storage battery and the lead storage battery are charged with electric power output from a generator (alternator). In this case, since the secondary battery other than the lead storage battery and the lead storage battery are connected in parallel to each other, it is necessary to control the lead storage battery and the secondary battery so as not to be insufficiently charged when charging by the generator. There is. However, in Patent Document 1, when charging a secondary battery and a lead storage battery other than the lead storage battery connected in parallel with each other, both the lead storage battery and the secondary battery do not become insufficiently charged. It has not been fully examined.

  Therefore, the present inventor configures a power supply unit by connecting a lead storage battery and a secondary battery other than the lead storage battery (in this embodiment, a nickel metal hydride storage battery) in parallel to each other, as in the technique described in Patent Document 1 above. did. And this inventor examined the change of the charging current of each battery at the time of carrying out constant voltage charge of the power supply part comprised in this way.

  FIG. 24 is a timing chart schematically showing a charging current when a power supply unit configured by connecting a lead storage battery and a nickel metal hydride storage battery in parallel to each other is subjected to constant voltage charging. In FIG. 24, the charging current Ipb indicates the charging current flowing through the lead storage battery, the charging current Ini indicates the charging current flowing through the nickel hydride storage battery, and the charging current It indicates the sum of the charging currents Ipb and Ini.

  Charging in FIG. 24 was performed under the following conditions. As the lead acid battery, a lead acid battery having a nominal voltage of 12 V in which six cell lead acid batteries are connected in series was used. As the nickel-metal hydride storage battery, a nickel-metal hydride storage battery having a nominal voltage of 10 V, in which 10 cells of nickel-metal hydride storage batteries are connected in series, is the same as the lead storage battery. Assuming a generator (alternator) used in the vehicle, charging was performed at a constant voltage of 14.5V.

  As a result, as shown in FIG. 24, it was found that Ipb> Ini during the initial period T0 (about 5 seconds) at the beginning of charging, but Ini> Ipb after the initial period T0. . Moreover, although illustration is abbreviate | omitted, when the lead acid battery and the lithium ion secondary battery were mutually connected in parallel, it turned out that the same charging characteristic is shown.

  About this cause, this inventor guessed that it originates in the difference in the charge characteristic of a lead acid battery, a nickel metal hydride storage battery, or a lithium ion secondary battery.

  First, the present inventor inferred that the following phenomenon occurred in each battery immediately after the start of charging. In the dissolution and precipitation type lead-acid battery, when the supply of the charging current is started, the chemical reaction of charging is immediately started between the electrode and the electrolytic solution on the electrode surface.

  In contrast, in a nickel metal hydride storage battery that uses a hydrogen storage alloy for the negative electrode, even when the supply of charging current is started, water is reduced and hydrogen atoms generated on the surface of the hydrogen storage alloy are stored in the hydrogen storage alloy. The reaction to metal hydride does not start immediately. Also in the positive electrode, it takes time to start the reaction in which nickel hydroxide is oxidized to produce nickel oxyhydroxide and water. For this reason, in the nickel metal hydride storage battery, the chemical reaction of charging is not started immediately.

  In addition, in an intercalation type lithium ion secondary battery in which the electrode is composed of a crystal of a layer structure, even if the supply of charging current is started, the interlayer of the crystal first spreads and lithium ions can easily enter the electrode. It takes time to reach such a state. For this reason, in the lithium ion secondary battery, the chemical reaction of charging is not started immediately. Therefore, during the initial period T0 (about 5 seconds) at the beginning of charging, the charging current of the lead storage battery is larger than the charging current of the nickel hydride storage battery or the lithium ion secondary battery.

  Next, the inventor has inferred that after the initial period T0 at the beginning of charging, the chemical reaction proceeds in each battery as follows. In lead-acid batteries, when the chemical reaction between the electrode and the electrolyte solution on the electrode surface is completed, it becomes a state of full charge in a pseudo state, and it takes time for the chemical reaction to proceed from the electrode surface to the lower layer. .

  On the other hand, in the nickel-metal hydride storage battery in which the hydrogen storage alloy once starts storing hydrogen atoms and nickel oxyhydroxide and water are generated from nickel hydroxide, the chemical reaction of charging proceeds smoothly. In addition, in a lithium ion secondary battery once in a state where lithium ions can easily enter the electrode, the chemical reaction of charging proceeds smoothly. Therefore, after the initial period T0 at the beginning of charging, the charging current of the nickel hydride storage battery or the lithium ion secondary battery becomes larger than the charging current of the lead storage battery.

  Here, charge control for the nickel metal hydride storage battery mounted on the vehicle will be described. If the state of charge (SOC) of the nickel-metal hydride storage battery is too high, the regenerative energy of the engine cannot be stored, so that the energy efficiency decreases. On the other hand, if the SOC of the nickel-metal hydride storage battery is too low, it will hinder the supply of a large current required when starting the engine or restarting the engine stopped by the idle stop control.

  For this reason, generally, in a nickel metal hydride storage battery mounted on a vehicle, an upper limit value (for example, 80%) and a lower limit value (for example, 20%) of the SOC are set. Charging and discharging of the nickel metal hydride storage battery are controlled so that the SOC of the nickel metal hydride storage battery is maintained within this range. Therefore, when the SOC of the nickel metal hydride storage battery reaches the upper limit during charging, the charging is stopped. In this case, the nickel metal hydride storage battery mounted on the vehicle is set to have a smaller capacity than the lead storage battery. For this reason, even with the same amount of charged electricity, the SOC of the nickel metal hydride storage battery varies greatly compared to the SOC of the lead storage battery. As a result, the SOC of the nickel metal hydride storage battery reaches the upper limit relatively quickly.

  Therefore, if the normal constant voltage charging is simply performed, the charging proceeds with the charging current as shown in FIG. 24. Therefore, before the lead storage battery is fully charged, the SOC of the nickel metal hydride storage battery reaches the upper limit value. Charging will be stopped. As a result, when the charge control is not devised, the lead storage battery continues to be in a state of insufficient charge that is not fully charged.

  On the other hand, it is conceivable to configure the charge control circuit of the power supply unit so that the lead storage battery and the nickel hydride storage battery can be charged separately. With this configuration, charging can be controlled so that both the lead storage battery and the nickel metal hydride storage battery do not become insufficiently charged. However, in the charge control circuit configured as described above, the circuit configuration becomes complicated and large, and thus the cost and installation space are increased.

  Therefore, the present inventor has come up with the invention of each aspect included in the second aspect according to the present disclosure as follows based on the above examination.

  According to a second aspect of the present disclosure, there is provided a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel to each other, and the power supply unit by constant voltage charging at a predetermined voltage value determined in advance. A charge control unit that charges the lead storage battery and the secondary battery, and the predetermined voltage value is an initial period at the beginning of charging at the predetermined voltage value, based on the charge current of the secondary battery. The charging current is increased, and after the initial period, the charging current of the secondary battery is predetermined to be larger than the charging current of the lead storage battery.

  In this aspect, the lead storage battery and the secondary battery of the power supply unit including the lead storage battery and the secondary battery other than the lead storage battery connected in parallel with each other are charged by constant voltage charging at a predetermined voltage value determined in advance. The predetermined voltage value is set in advance to a value at which the charging current of the lead storage battery is larger than the charging current of the secondary battery during the initial period at the beginning of charging at the predetermined voltage value. For this reason, insufficient charging of the lead storage battery is avoided. In addition, after the initial period, the charging current of the secondary battery is predetermined to be larger than the charging current of the lead storage battery. For this reason, insufficient charging of the secondary battery is avoided. As a result, according to this aspect, it is possible to avoid both the lead storage battery and the secondary battery from being insufficiently charged with a simple configuration.

  2nd aspect WHEREIN: The 1st SOC acquisition part which acquires SOC of the said lead acid battery, The memory | storage part which preserve | saves the SOC threshold value of 100% or less predetermined as SOC of the said lead acid battery, Charge voltage is the said predetermined voltage A voltage adjustment unit that adjusts the value or a predetermined low voltage value lower than the predetermined voltage value, and the charge control unit controls the voltage adjustment unit to acquire the lead acquired by the first SOC acquisition unit The charging voltage is adjusted to the predetermined low voltage value until the SOC of the storage battery reaches the SOC threshold, and the charging voltage is adjusted to the predetermined voltage value after the SOC of the lead storage battery reaches the SOC threshold. The lead storage battery and the secondary battery of the power supply unit are charged by two-stage constant voltage charging. The predetermined low voltage value is such that the charging current of the lead storage battery is larger than the charging current of the secondary battery. It may be determined in advance to become a value.

  In this aspect, the lead storage battery and the secondary battery are charged at a constant voltage at a predetermined low voltage value until the SOC of the lead storage battery reaches the SOC threshold. The predetermined low voltage value is set in advance to a value at which the charging current of the lead storage battery is larger than the charging current of the secondary battery. For this reason, until the SOC of the lead storage battery reaches the SOC threshold, the lead storage battery is charged faster than the secondary battery. Therefore, according to this aspect, it is possible to avoid insufficient charging such that the SOC of the lead storage battery is less than the SOC threshold.

  Further, in this aspect, after the SOC of the lead storage battery reaches the SOC threshold, the lead storage battery and the secondary battery are charged at a constant voltage with a predetermined voltage value. The predetermined voltage value is such that the charging current of the lead-acid battery is larger than the charging current of the secondary battery during the initial period of the start of charging at the predetermined voltage value, and after the initial period, the charging current of the lead-acid battery is secondary The value is predetermined to increase the charging current of the battery. For this reason, after the SOC of the lead storage battery reaches the SOC threshold, charging of the secondary battery proceeds faster than the lead storage battery. Therefore, according to this aspect, the secondary battery can be prevented from being insufficiently charged. As a result, according to this aspect, it is possible to avoid both the lead storage battery and the secondary battery from being insufficiently charged with a simple configuration.

  In the second aspect, for example, a second SOC acquisition unit that acquires the SOC of the secondary battery is further provided, and the storage unit is a first SOC upper limit value less than 100% that is predetermined as the SOC of the secondary battery. The charge control unit may stop the two-stage constant voltage charging when the SOC of the secondary battery acquired by the second SOC acquisition unit reaches the first SOC upper limit value.

  According to this aspect, the two-stage constant voltage charging is stopped when the SOC of the secondary battery reaches a predetermined first SOC upper limit value of less than 100%. Therefore, the secondary battery can be prevented from being overcharged.

  In the second aspect, for example, the charge control unit may increase the SOC threshold value as the SOC of the secondary battery at the start of charging acquired by the second SOC acquisition unit increases.

  In this aspect, charging is stopped when the SOC of the secondary battery reaches a first SOC upper limit value less than a predetermined 100%. Therefore, the larger the SOC of the secondary battery at the start of charging, the shorter the constant voltage charging time at the second voltage value. For this reason, the possibility that the lead storage battery becomes insufficiently charged increases as the SOC of the secondary battery at the start of charging increases. On the other hand, according to this aspect, the SOC threshold value is set to a larger value as the SOC of the secondary battery at the start of charging is larger. Accordingly, the constant voltage charging time at the first voltage value becomes longer. As a result, it is possible to reduce the possibility of the lead storage battery becoming insufficiently charged.

  In the second aspect, for example, the storage unit stores a second SOC upper limit value that exceeds a predetermined 100% as the SOC of the lead storage battery, and the charge control unit stores the SOC of the lead storage battery in the first mode. When the 2SOC upper limit value is reached, the two-stage constant voltage charging may be stopped.

  In this aspect, when the SOC of the lead storage battery reaches a second SOC upper limit value that exceeds a predetermined value of 100%, the two-stage constant voltage charging is stopped. Therefore, when charging is continued until the SOC of the lead storage battery reaches the second SOC upper limit value, it is possible to suppress excessive sulfation that occurs in the lead storage battery due to insufficient charging.

  In the second aspect, for example, the storage unit stores an SOC lower limit value lower than the SOC threshold value that is predetermined as the SOC of the lead storage battery, and the charge control unit is configured so that the SOC of the lead storage battery is the SOC. When the value falls below the lower limit value, the number of times of reduction is counted, and the number of times counted is charged at a predetermined number of times by charging the lead storage battery and the secondary battery of the power supply unit by the two-stage constant voltage charging, and the counting When the number of times of the charging is less than the predetermined number of times, the charging voltage may be adjusted to the second voltage value, and the lead storage battery and the secondary battery of the power supply unit may be charged at a constant voltage.

  In this aspect, when the SOC of the lead storage battery falls below the SOC lower limit value, the number of times of reduction is counted. Each battery of the power supply unit is charged by two-stage constant voltage charging every predetermined number of times. Therefore, when charging is continued until the SOC of the lead storage battery reaches the second SOC upper limit value, it is possible to suppress excessive sulfation that occurs in the lead storage battery due to insufficient charging.

  On the other hand, when the counted number is less than the predetermined number, the charging voltage is adjusted to the second voltage value, and each battery of the power supply unit is charged by constant voltage charging at the second voltage value. For this reason, the overcharge such that the SOC of the lead storage battery reaches the second SOC upper limit value is performed every predetermined number of times, and is not performed when it is less than the predetermined number of times. As a result, it is possible to avoid excessive deterioration of the lead storage battery due to overcharge.

  In the second aspect, for example, in the two-stage constant voltage charging, the charging control unit may adjust the charging voltage to the second voltage value when the SOC of the lead storage battery reaches the SOC threshold value. The lead storage battery and the secondary battery of a part may be pulse-charged with an on period having a length equal to or shorter than the initial period.

  In this aspect, when the SOC of the lead storage battery reaches the SOC threshold value and the charging voltage is adjusted to the second voltage value, each battery of the power supply unit is pulse-charged with an on-period that is shorter than the initial period. Since the on period is equal to or shorter than the initial period, the charging current of the lead storage battery is larger than the charging current of the secondary battery in the on period. Therefore, although the charging voltage is adjusted to the second voltage value, in the charge charging, the lead storage battery is charged faster than the secondary battery. As a result, it is possible to avoid the lead storage battery from being insufficiently charged.

  In the second aspect, a secondary battery SOC acquisition unit that acquires the SOC of the secondary battery, and a storage unit that stores a first SOC upper limit value less than 100% predetermined as the SOC of the secondary battery; The charge control unit further includes the power supply by constant voltage charging at the predetermined voltage value while the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is less than the first SOC upper limit value. When the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is equal to or higher than the first SOC upper limit value, the lead storage battery and the secondary battery of the unit are charged in advance. You may switch to the pulse charge which repeats an ON period and an OFF period alternately.

  In this aspect, while the SOC of the secondary battery is less than the first SOC upper limit value, the lead storage battery and the secondary battery are charged at a constant voltage with a predetermined voltage value. The predetermined voltage value is such that the charging current of the lead-acid battery is larger than the charging current of the secondary battery during the initial period of the start of charging at the predetermined voltage value, and after the initial period, the charging current of the lead-acid battery is secondary It is set to a value that increases the charging current of the battery. For this reason, in the constant voltage charging, the charging of the secondary battery proceeds faster than the lead storage battery. Therefore, according to this aspect, the secondary battery can be prevented from being insufficiently charged.

  Further, in this aspect, when the SOC of the secondary battery becomes equal to or higher than the first SOC upper limit value, the charging is switched to pulse charging that alternately repeats a predetermined on period and off period. In pulse charging, the charging current of the lead storage battery is larger than the charging current of the secondary battery. For this reason, charge of a lead storage battery progresses quickly compared with a secondary battery. Therefore, according to this aspect, the lead storage battery can be prevented from being insufficiently charged. As a result, according to this aspect, it is possible to avoid both the lead storage battery and the secondary battery from being insufficiently charged with a simple configuration.

  In the second aspect, for example, the charging control unit may predetermine the on period to be equal to or shorter than the initial period.

  In this aspect, the on period is set to a length equal to or shorter than the initial period. For this reason, in the ON period, the charging current of the lead storage battery is larger than the charging current of the secondary battery. Therefore, in the pulse charging, the lead storage battery is charged faster than the secondary battery. Therefore, according to this aspect, it is possible to avoid the lead storage battery from being insufficiently charged.

  In the second aspect, for example, the storage unit stores, as the SOC of the secondary battery, a predetermined SOC protection threshold value that is less than 100% and exceeds the first SOC upper limit value. The control unit may stop the pulse charging when the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit becomes equal to or higher than the SOC protection threshold during the pulse charging.

  In the pulse charging, charging of the lead storage battery proceeds faster than the secondary battery, but charging of the secondary battery proceeds while being slower than the lead storage battery. However, according to this aspect, during the pulse charging, when the SOC of the secondary battery is less than 100% and exceeds the first SOC upper limit value, the pulse charging is stopped. The Therefore, it is possible to avoid the SOC of the secondary battery from becoming excessive.

  In the second aspect, for example, the storage unit stores a predetermined first SOC lower limit value lower than the first SOC upper limit value as the SOC of the secondary battery, and the charge control unit performs the pulse charging. In addition, when the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit becomes less than the first SOC lower limit value, the pulse charging may be switched to the constant voltage charging.

  In this aspect, when the SOC of the secondary battery becomes less than the first SOC lower limit value set in advance below the first SOC upper limit value during pulse charging, the pulse charge is switched to constant voltage charging. In the constant voltage charging, the charging of the secondary battery proceeds faster than the lead storage battery. Therefore, according to this aspect, it is possible to avoid that the SOC of the secondary battery is maintained below the first SOC lower limit value.

  In the second aspect, for example, a lead storage battery SOC acquisition unit that acquires the SOC of the lead storage battery is further provided, and the storage unit has a second SOC upper limit value that is predetermined as 100% or more as the SOC of the lead storage battery. The charging control unit may stop the pulse charging when the SOC of the lead storage battery acquired by the lead storage battery SOC acquisition unit is equal to or higher than the second SOC upper limit value during the pulse charging.

  In this aspect, when the SOC of the lead-acid battery becomes equal to or higher than the second SOC upper limit value set in advance to 100% or higher during pulse charging, the pulse charging is stopped. Therefore, even if the SOC of the lead storage battery becomes equal to or higher than the second SOC upper limit value, charging can be continued and the lead storage battery can be prevented from being overcharged.

  In the second aspect, for example, the storage unit stores 100% and a value exceeding 100% as the second SOC upper limit value, and is preset to less than 100% as the SOC of the lead storage battery. 2SOC lower limit value is stored, and when the SOC of the lead storage battery falls below the second SOC lower limit value, the charging control unit counts the number of times of decrease and starts the constant voltage charging, and the counted number of times is predetermined. For each number of times, a value exceeding 100% may be used as the second SOC upper limit value, and when the counted number is less than the predetermined number, 100% may be used as the second SOC upper limit value.

  In this aspect, when the SOC of the lead storage battery falls below the SOC lower limit value, the number of drops is counted and constant voltage charging is started. A value exceeding 100% is used as the second SOC upper limit value every predetermined number of times. Therefore, in the case where charging is continued until the SOC of the lead storage battery becomes equal to or higher than the second SOC upper limit value, it is possible to suppress excessive advancement of sulfation generated in the lead storage battery due to insufficient charging.

  On the other hand, when the counted number is less than the predetermined number, 100% is used as the second SOC upper limit value. For this reason, the overcharge that the SOC of the lead storage battery exceeds 100% is performed every predetermined number of times, and is not performed when it is less than the predetermined number of times. As a result, it is possible to avoid excessive deterioration of the lead storage battery due to overcharge.

  Another aspect according to the present disclosure includes a lead storage battery connected in parallel to each other and a power supply unit including a secondary battery other than the lead storage battery, and charging that controls charging of the lead storage battery and the secondary battery of the power supply unit A charge control method for a control device, comprising: a predetermined voltage charging step of performing constant voltage charging of the lead storage battery and the secondary battery of the power supply unit at a predetermined voltage value, wherein the predetermined voltage value is: In the initial period at the beginning of charging at the predetermined voltage value, the charging current of the lead storage battery is larger than the charging current of the secondary battery, and after the initial period, the charging current of the lead storage battery is more than the secondary current. The value is predetermined to increase the charging current of the secondary battery.

  In the other aspect, a lead storage battery SOC acquisition step for acquiring the SOC of the lead storage battery, and a predetermined low value lower than the predetermined voltage value until the SOC of the lead storage battery reaches a predetermined SOC threshold value of 100% or less. A low voltage charging step of charging the lead storage battery and the secondary battery of the power supply unit at a constant voltage with a voltage value, wherein the predetermined voltage charging step has reached the SOC threshold of the lead storage battery The predetermined low voltage value may be executed later, and may be set in advance to a value at which a charging current of the lead storage battery is larger than a charging current of the secondary battery.

  In the other aspect, the secondary battery SOC acquisition step for acquiring the SOC of the secondary battery, and the secondary battery SOC acquired in the secondary battery SOC acquisition step is less than a predetermined 100% SOC. A pulse charging step of charging the lead storage battery and the secondary battery of the power supply unit by pulse charging that repeats a predetermined on-period and off-period when the SOC exceeds the upper limit of 1 SOC, and the predetermined voltage charging step May be executed while the SOC of the secondary battery acquired in the secondary battery SOC acquisition step is less than the first SOC upper limit value.

(Second Embodiment)
FIG. 6 is a block diagram schematically showing the configuration of the vehicle 1 including the battery control unit 180 and the ECU 70 of the second embodiment.

  The vehicle 1 is a hybrid electric vehicle having an engine as a main power source and a motor as an auxiliary power source. The vehicle 1 includes an engine 10, a starter motor 20, an integrated starter generator (ISG) 30, a voltage adjustment unit 31, a switch element 35, an electrical load 40, a power supply unit 45, an electronic control unit (ECU) 70, and a battery control unit 180. .

  The power supply unit 45 includes a lead storage battery 50, current sensors 51 and 63, and a nickel metal hydride storage battery (Ni-MH) 61. The lead storage battery 50 and the nickel metal hydride storage battery 61 are connected in parallel to each other. The connection point K2 on the negative electrode side of the lead storage battery 50 and the nickel hydride storage battery 61 is grounded. The starter motor 20, ISG 30, and electrical load 40 are connected in parallel with the power supply unit 45. A power supply voltage Vcc is supplied from the power supply unit 45 to the battery control unit 180 and the ECU 70.

  The lead storage battery 50 includes a 6-cell lead storage battery connected in series. With this configuration, the nominal voltage of the lead storage battery 50 is 12V. The nickel hydride storage battery 61 includes 10 cells of nickel hydride storage batteries connected in series. With this configuration, the nominal voltage of the nickel metal hydride storage battery 61 is 12V. The electric power output from the power supply unit 45 is used to drive the starter motor 20 and the ISG 30 that start the engine 10 of the vehicle 1 and to power the electrical load 40.

  The current sensor 51 detects a charging current or a discharging current flowing through the lead storage battery 50. The current sensor 51 is attached on the branch line L1 branched from the connection point K1 on the positive electrode side of the lead storage battery 50 and the nickel metal hydride storage battery 61. The current sensor 51 is provided for calculating the charge electricity amount and the discharge electricity amount of the lead storage battery 50.

  The current sensor 63 detects a charging current or a discharging current flowing through the nickel metal hydride storage battery 61. The current sensor 63 is attached on the branch line L2 branched from the connection point K1 on the positive electrode side of the lead storage battery 50 and the nickel hydride storage battery 61. The current sensor 63 is provided for calculating the charge electricity amount and the discharge electricity amount of the nickel metal hydride storage battery 61.

  The current sensors 51 and 63 are, for example, Hall effect type current sensors including Hall elements. Alternatively, the current sensors 51 and 63 may include a shunt resistor and detect a current based on a voltage drop of the shunt resistor.

  The starter motor 20 starts the engine 10 when the ignition switch is operated by the user.

  The ISG 30 has both a power generation function and an electric function. When the engine 10 of the vehicle 1 is operating, the ISG 30 is driven by the engine 10 and generates power by a power generation function. When the generated power exceeds the electrical load of the electrical load 40, the lead storage battery 50 and the nickel hydride storage battery 61 of the power supply unit 45 are charged by the generated power. Further, when a brake pedal (not shown) is operated while the vehicle 1 is traveling and starts decelerating, torque is transmitted from the wheels to the ISG 30, and the ISG 30 generates power by a power generation function. The lead-acid battery 50 and the nickel-metal hydride storage battery 61 of the power supply unit 45 are charged by the generated power. This regenerates energy. When the vehicle 1 stops, the engine 10 is automatically stopped by the idle stop control of the ECU 70. When the vehicle 1 starts, the vehicle 1 is driven by the electric function of the ISG 30 and the engine 10 is started.

  The voltage adjustment unit 31 adjusts the output voltage of the ISG 30. If the output voltage by the power generation function of the ISG 30 is not adjusted, it changes depending on the rotation speed of the engine 10, the current value of the load current, and the field current. The voltage adjustment unit 31 adjusts the output voltage of the ISG 30 to a constant value by increasing or decreasing the field current, for example. The voltage adjustment unit 31 includes, for example, a semiconductor circuit in which a power transistor and a voltage detection circuit are integrated. In the second embodiment, the voltage adjustment unit 31 adjusts the output voltage of the ISG 30 in two stages, for example, DC 13.7V (an example of a first voltage value) and DC 15.0V (an example of a second voltage value). To do.

  The switch element 35 is provided between the ISG 30 and the power supply unit 45. The switch element 35 is turned on when the engine 10 is stopped. The switch element 35 is turned off when charging of the lead storage battery 50 and the nickel metal hydride storage battery 61 is stopped. On / off of the switch element 35 is controlled by the battery control unit 180. The switch element 35 may be a mechanical relay. Alternatively, the switch element 35 may be a semiconductor switch such as a power MOSFET or an insulated gate bipolar transistor. The electrical load 40 includes a load such as an electrical component equipped in the vehicle 1 such as an air conditioner and a room light.

  The ECU 70 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) in which a predetermined control program is stored, a RAM (Random Access Memory) in which data is temporarily stored, these Peripheral circuits are provided. The ECU 70 is configured to be able to communicate with the battery control unit 180.

  The ECU 70 controls the overall operation of the vehicle 1 including the engine 10, the starter motor 20, the ISG 30, the voltage adjustment unit 31, and the electrical load 40. The ECU 70 receives the control signal SG output from the battery control unit 180 and controls the voltage adjustment unit 31.

  The battery control unit 180 includes, for example, a CPU that executes predetermined arithmetic processing, a ROM that stores a predetermined control program, a RAM that temporarily stores data, and peripheral circuits thereof. The battery control unit 180 includes a storage unit 181 composed of, for example, a flash memory. The battery control unit 180 functions as a first SOC calculation unit 182, a second SOC calculation unit 183, a voltage control unit 184, and a switch control unit 185 by executing a control program stored in the ROM.

  Storage unit 181 stores in advance a table 88 representing a relationship between SOC threshold value Spb1 of 100% or less, which is predetermined as the SOC of lead storage battery 50, and SOC value Sni1 of nickel metal hydride storage battery 61 at the start of charging.

  FIG. 7 is a diagram schematically showing an example of the table 88. In the second embodiment, as shown in FIG. 7, when the SOC value Sni1 of the nickel metal hydride storage battery 61 at the start of charging is Sni1 <30, the SOC threshold value Spb1 is 97, and 30 ≦ Sni1 <40. In this case, the SOC threshold value Spb1 is 98. When 40 ≦ Sni1 <50, the SOC threshold value Spb1 is 99. When 50 ≦ Sni1, the SOC threshold value Spb1 is 100. As shown in FIG. 7, the larger the SOC value Sni1 of the nickel metal hydride storage battery 61 at the start of charging, the larger the SOC threshold Spb1 of the lead storage battery 50 is used. The reason for this will be described later with reference to FIG.

  Returning to FIG. 6, the storage unit 181 includes an SOC upper limit value Sni2 (an example of the first SOC upper limit value) that is predetermined as the upper limit value of the SOC of the nickel metal hydride storage battery 61, and an SOC lower limit value Sni3 that is predetermined as the lower limit value. Are stored in advance. In the second embodiment, for example, Sni2 = 80% and Sni3 = 20%.

  Storage unit 181 stores in advance an SOC upper limit value Spb2 (an example of a second SOC upper limit value) that exceeds 100% that is predetermined as the upper limit value of the SOC of lead-acid battery 50. In the second embodiment, for example, Spb2 = 105%.

  Storage unit 181 stores in advance a SOC lower limit value Spb3 determined in advance as the lower limit value of the SOC of lead-acid battery 50. The SOC lower limit Spb3 is set to be less than the SOC threshold Spb1, for example. In the second embodiment, for example, Spb3 = 80%.

  The battery control unit 180 controls the charging and discharging of the nickel-metal hydride storage battery 61 so that the SOC of the nickel-metal hydride storage battery 61 is maintained within the range between the SOC upper limit value Sni2 and the SOC lower limit value Sni3. The battery control unit 180 controls the charging and discharging of the lead storage battery 50 so that the SOC of the lead storage battery 50 is maintained at the SOC lower limit Spb3 or more.

  The first SOC calculation unit 182 calculates the charge electricity amount and the discharge electricity amount of the lead storage battery 50 using the current value detected by the current sensor 51. The first SOC calculation unit 182 calculates the SOC of the lead storage battery 50 using the calculated amount of charge and discharge of the lead storage battery 50. The first SOC calculation unit 182 calculates the SOC every 100 msec, for example. The first SOC calculation unit 182 and the current sensor 51 correspond to an example of a first SOC acquisition unit.

  The second SOC calculation unit 183 calculates the charge electricity amount and the discharge electricity amount of the nickel-metal hydride storage battery 61 using the current value detected by the current sensor 63. The second SOC calculation unit 183 calculates the SOC of the nickel metal hydride storage battery 61 using the calculated charge electricity amount and discharge electricity amount of the nickel metal hydride storage battery 61. The second SOC calculation unit 183 calculates the SOC every 100 msec, for example. The second SOC calculation unit 183 and the current sensor 63 correspond to an example of a second SOC acquisition unit.

  The voltage control unit 184 outputs a control signal SG to the ECU 70 to control the charging voltage during charging of the lead storage battery 50 and the nickel metal hydride storage battery 61. The voltage controller 184 acquires the SOC of the lead storage battery 50 from the first SOC calculator 182. The voltage control unit 184 outputs a control signal SG to the ECU 70 so that the charging voltage is controlled to 13.7 V until the obtained SOC of the lead storage battery 50 reaches the SOC threshold value Spb1. When the control signal SG is input, the ECU 70 controls the voltage adjusting unit 31 to set the output voltage of the ISG 30 to 13.7V.

  The voltage control unit 184 outputs a control signal SG to the ECU 70 so as to control the charging voltage to 15.0 V after the SOC of the lead storage battery 50 calculated by the first SOC calculation unit 182 reaches the SOC threshold value Spb1. . When the control signal SG is input, the ECU 70 controls the voltage adjusting unit 31 to set the output voltage of the ISG 30 to 15.0V. Thus, the voltage control unit 184 and the ECU 70 charge the lead storage battery 50 and the nickel hydride storage battery 61 by two-stage constant voltage charging.

  FIG. 8 is a timing chart schematically showing a charging current when the power supply unit 45 of FIG. 6 is charged at a constant voltage of 13.7V.

  In FIG. 8, unlike FIG. 24 described above, the charging current Ini of the nickel-metal hydride storage battery 61 does not exceed the charging current Ipb of the lead storage battery 50. The cause of this is estimated as follows. In the dissolution / precipitation type lead-acid battery 50, even when the voltage is 13.7 V, the chemical reaction of charging proceeds although the speed is low. However, in the nickel metal hydride storage battery 61, since the voltage is too low at 13.7 V, the hydrogen storage alloy does not easily store hydrogen, so that the chemical reaction of charging hardly proceeds. Therefore, when the power supply unit 45 of FIG. 6 is charged at a constant voltage of 13.7 V, the charging current Ipb of the lead storage battery 50 becomes larger than the charging current Ini of the nickel metal hydride storage battery 61.

  As can be seen from a comparison between FIG. 8 and FIG. 24, the total charging current It is about half that of FIG. 24 in FIG. For this reason, it takes time to charge the lead storage battery 50 and the nickel metal hydride storage battery 61. However, by adjusting the output voltage of the ISG 30 to 13.7 V, the charging of the lead storage battery 50 can be advanced faster than the nickel metal hydride storage battery 61.

  Returning to FIG. 6, the voltage control unit 184 determines the SOC threshold value Spb1 using the SOC of the nickel-metal hydride storage battery 61 at the time when the supply of the charging current from the ISG 30 is started and the table 88 shown in FIG. .

  The voltage control unit 184 counts the number of times the SOC of the lead storage battery 50 calculated by the first SOC calculation unit 182 has decreased to the SOC lower limit value Spb3 or less. Every time the count value is N (N = 5 in the second embodiment, for example), the voltage control unit 184 performs the two-stage constant voltage control. When the count value is 1 to (N−1) times, that is, when the count value is less than N times, the voltage control unit 184 does not perform the above-described two-stage constant voltage control, and outputs the output voltage of the ISG 30 to 15. Control to 0 V to perform normal constant voltage charging.

  The switch control unit 185 controls on / off of the switch element 35. The switch control unit 185 turns on the switch element 35 when the engine 10 is stopped. When the SOC of the nickel metal hydride storage battery 61 calculated by the second SOC calculation unit 183 increases to the SOC upper limit value Sni2 or more during charging, the switch control unit 185 turns off the switch element 35 and stops charging.

  When the SOC of the lead storage battery 50 calculated by the first SOC calculation unit 182 increases to the SOC upper limit value Spb2 or more during charging, the switch control unit 185 turns off the switch element 35 and stops charging.

  FIG. 9 is a flowchart schematically showing the charging operation of the second embodiment. FIG. 10 is a diagram schematically showing an example of the SOC of the lead storage battery 50 and the nickel metal hydride storage battery 61 that are increased by the charging operation of FIG. 9. The vertical axis in FIG. 10 represents the SOC of the lead storage battery 50, and the horizontal axis represents the SOC of the nickel metal hydride storage battery 61. In FIG. 10, charging periods Tch1 and Tch11 represent periods in which constant voltage charging at 13.7V is performed, and charging periods Tch2 and Tch12 represent periods in which constant voltage charging at 15.0V is performed.

  In the second embodiment, the SOC of the lead storage battery 50 and the nickel metal hydride storage battery 61 changes as represented by the charging periods Tch1 and Tch2. The SOC of the lead storage battery 50 and the nickel metal hydride storage battery 61 represented by the charging periods Tch11 and Tch12 represents a comparative example described later. In the normal state (that is, when the operation of FIG. 9 is started), the switch element 35 is turned on.

  In S101 of FIG. 9 (an example of a lead storage battery SOC acquisition step), first, the voltage control unit 184 acquires the SOC value of the lead storage battery 50 from the first SOC calculation unit 182. Voltage control unit 184 determines whether or not the obtained SOC value of lead storage battery 50 is less than SOC lower limit value Spb3. If the SOC value of lead storage battery 50 is less than SOC lower limit Spb3 (YES in S101), voltage control unit 184 increases count value Ct by 1 in S102.

  In S103, the voltage control unit 184 determines whether the count value Ct is less than N (N = 5 in the second embodiment). If the count value Ct is greater than or equal to N (NO in S103), the voltage control unit 184 resets the count value Ct to 0 in S104. In S105, the voltage control unit 184 obtains the SOC value Sni1 of the nickel metal hydride storage battery 61 from the second SOC calculation unit 183. The voltage control unit 184 refers to the table 88 and extracts the SOC threshold value Spb1 of the lead storage battery 50 corresponding to the obtained SOC value Sni1 of the nickel metal hydride storage battery 61.

  In S106 (an example of a low voltage charging step), the voltage control unit 184 outputs a control signal SG requesting to adjust the output voltage of the ISG 30 to 13.7 V to the ECU 70. When the ECU 70 receives the control signal SG, the ECU 70 controls the voltage adjusting unit 31 to adjust the output voltage of the ISG 30 to 13.7V. Thereby, the lead storage battery 50 and the nickel metal hydride storage battery 61 of the power supply unit 45 are charged at a constant voltage of 13.7V.

  In S <b> 107, the voltage control unit 184 acquires the SOC value of the lead storage battery 50 from the first SOC calculation unit 182. The voltage control unit 184 determines whether or not the obtained SOC value of the lead storage battery 50 is equal to or higher than the SOC threshold value Spb1. If the SOC value of lead storage battery 50 is less than SOC threshold value Spb1 (NO in S107), the process returns to S107, and constant voltage charging at 13.7 V is continued.

  As described with reference to FIG. 8, when the voltage is 13.7 V, the charging current of the lead storage battery 50 is larger than the charging current of the nickel metal hydride storage battery 61. Therefore, as shown in FIG. 10, the SOC of the lead storage battery 50 increases faster than the SOC of the nickel metal hydride storage battery 61 in the charging period Tch1. In FIG. 10, the SOC value Sni1 of the nickel-metal hydride storage battery 61 obtained in S5 of FIG. 9 is 20 ≦ Sni1 <30. For this reason, the SOC threshold value Spb1 extracted from the table 88 (FIG. 7) in S5 of FIG. 9 is 97 as shown in FIG.

  Returning to FIG. 9, in S107 (an example of the lead storage battery SOC acquisition step), if the SOC value of the lead storage battery 50 is equal to or greater than the SOC threshold value Spb1 (YES in S107), the voltage control unit 184 determines whether the SOC is S108 (predetermined voltage charging). In an example of a step, a control signal SG that requests to adjust the output voltage of the ISG 30 to 15.0 V is output to the ECU 70. When the ECU 70 receives the control signal SG, the ECU 70 controls the voltage adjustment unit 31 to adjust the output voltage of the ISG 30 to 15.0V. As a result, the lead storage battery 50 and the nickel hydride storage battery 61 of the power supply unit 45 are charged at a constant voltage of 15.0V.

  As described with reference to FIG. 24, when the voltage is 15.0 V, the charging current of the nickel-metal hydride storage battery 61 is larger than the charging current of the lead storage battery 50 except for the initial period T0 at the beginning of charging. Therefore, as shown in FIG. 10, the SOC of the nickel-metal hydride storage battery 61 increases faster than the SOC of the lead storage battery 50 in the charging period Tch2.

  Returning to FIG. 9, in S <b> 109, the switch control unit 185 acquires the SOC value of the nickel metal hydride storage battery 61 from the second SOC calculation unit 183. The switch control unit 185 determines whether or not the acquired SOC value of the nickel metal hydride storage battery 61 is equal to or higher than the SOC upper limit value Sni2. If the SOC value of nickel-metal hydride storage battery 61 is less than SOC upper limit value Sni2 (NO in S109), switch control unit 185 acquires the SOC value of lead storage battery 50 from first SOC calculation unit 182 in S110. The switch control unit 185 determines whether or not the SOC value of the lead storage battery 50 is equal to or higher than the SOC upper limit value Spb2. If the SOC value of lead storage battery 50 is less than SOC upper limit value Spb2 (NO in S110), the process returns to S109, and constant voltage charging at 15.0 V is continued.

  In S109, if the SOC value of the nickel-metal hydride storage battery 61 is equal to or higher than the SOC upper limit value Sni2 (YES in S109), in S110, the switch control unit 185 turns off the switch element 35 to stop the charging, and FIG. The process ends. In S110, if the SOC value of lead storage battery 50 is equal to or higher than SOC upper limit Spb2 (YES in S110), the process proceeds to S111.

  If the SOC value of the lead storage battery 50 is equal to or higher than the SOC lower limit value Spb3 in S101 (NO in S101), the voltage control unit 184 acquires the SOC value of the nickel metal hydride storage battery 61 from the second SOC calculation unit 183 in S112. . The voltage control unit 184 determines whether or not the acquired SOC value of the nickel metal hydride storage battery 61 is less than the SOC upper limit value Sni2. If the SOC value of nickel-metal hydride storage battery 61 is greater than or equal to SOC upper limit value Sni2 (NO in S112), the process proceeds to S11.

  In S112, if the SOC value of nickel metal hydride storage battery 61 is less than SOC upper limit value Sni2 (YES in S112), the process proceeds to S108. In S103, if the count value Ct is less than N (YES in S103), the process proceeds to S108. As a result, normal constant voltage charging at 15.0 V is performed in S108.

  As shown in S109 and S110 of FIG. 9, when either the SOC value of the nickel hydride storage battery 61 or the SOC value of the lead storage battery 50 increases to the SOC upper limit value or more, the switch element 35 is turned off and the charging is stopped. Is done. In the example of FIG. 10, the charging is stopped when the SOC value of the nickel-metal hydride storage battery 61 reaches the SOC upper limit value Sni2.

  Thus, every time the SOC value of the lead storage battery 50 decreases to N times or less than the SOC lower limit value Spb3, the constant voltage charging at a voltage of 13.7 V and the constant voltage charging at a voltage of 15.0 V are included. Step constant voltage charging is performed. When the SOC value of the lead storage battery 50 exceeds the SOC lower limit value Spb3, and when the SOC value of the lead storage battery 50 decreases to the SOC lower limit value Spb3 or less (N-1) times, the voltage The normal constant voltage charging at 15.0V is performed.

  According to this 2nd Embodiment, as FIG. 10 shows, the overcharge which the SOC value of the lead storage battery 50 exceeds 100% is performed. Thereby, it is possible to suppress the sulfation generated in the insufficiently charged lead storage battery 50 from proceeding excessively. The overcharge is not performed every time the SOC value of the lead storage battery 50 decreases to the SOC lower limit value Spb3 or less, but the N (this first value) decreases the SOC value of the lead storage battery 50 to the SOC lower limit value Spb3 or less. In the second embodiment, for example, N = 5). For this reason, the lead storage battery 50 does not deteriorate excessively due to overcharging.

  As shown in FIG. 7, the larger the SOC value Sni1 of the nickel hydride storage battery 61 at the start of charging, the larger the SOC threshold value Spb1 of the lead storage battery 50 is used. The reason for this will be described with reference to FIG.

  In FIG. 10, the SOC value Sni1 of the nickel metal hydride storage battery 61 at the start of charging in the charging period Tch1 is Sni1 <30. Therefore, as described using FIG. 7, the SOC threshold value Spb1 of the lead storage battery 50 is set to 97%. As shown in FIG. 10, when the SOC value of the lead storage battery 50 reaches the SOC threshold value Spb1 (97% in FIG. 10) (that is, at the end of the charging period Tch1), the SOC value of the nickel hydride storage battery 61 is 50%. Not reached.

  Therefore, since it takes time for the SOC value of the nickel metal hydride storage battery 61 to reach 80%, there is sufficient time for constant voltage charging (charging period Tch2) at 15.0V. For this reason, as shown in FIG. 10, when the SOC value of the nickel-metal hydride storage battery 61 reaches 80%, the SOC value of the lead storage battery 50 exceeds 100%. Therefore, insufficient charging of the lead storage battery 50 can be resolved.

  On the other hand, in the comparative example of FIG. 10, the SOC value Sni1 of the nickel metal hydride storage battery 61 at the start of charging in the charging period Tch11 is 50%. In this case, when the SOC value of the lead storage battery 50 reaches 97%, the SOC value of the nickel metal hydride storage battery 61 is close to 70%. For this reason, since the SOC value of the nickel-metal hydride storage battery 61 reaches 80% in a short time, the charging period Tch12 is shortened. Therefore, the SOC value of the lead storage battery 50 does not exceed 100% at the end of the charging period Tch12 when the SOC value of the nickel hydride storage battery 61 has reached 80%.

  Therefore, in the second embodiment, as shown in FIG. 7, the SOC threshold value Spb1 of the lead storage battery 50 is set to a larger value as the SOC value of the nickel metal hydride storage battery 61 at the start of charging is larger. Therefore, at the end of the constant voltage charging time (charging period Tch1) at 13.7 V, the SOC value of the lead storage battery 50 is close to 100%. Thereby, even if the time of constant voltage charging at 15.0 V (charging period Tch2) is short, the SOC value of the lead storage battery 50 exceeds 100%. As a result, it is possible to suppress the sulfation that occurs in the insufficiently charged lead storage battery 50 from proceeding excessively.

(Third embodiment)
FIG. 11 is a flowchart schematically showing the charging operation of the third embodiment. FIG. 12 is a diagram schematically showing an example of the SOC of the lead storage battery 50 and the nickel metal hydride storage battery 61 that are increased by the charging operation of FIG. 11. FIG. 13 is a timing chart schematically showing the operation of the switch element 35. The configuration of the third embodiment is the same as that of the second embodiment shown in FIG. Hereinafter, the third embodiment will be described focusing on differences from the second embodiment.

  In FIG. 11, S101 to S107 are the same as S101 to S107 of FIG. 9 of the second embodiment. Due to the constant voltage charging at 13.7 V in S106 and S107, the SOC of the lead storage battery 50 is higher than the SOC of the nickel metal hydride storage battery 61 in the charging period Tch1 in FIG. 12, as in the second embodiment (FIG. 10). However, it increases quickly.

  In S107, if the SOC value of lead storage battery 50 is equal to or higher than SOC threshold value Spb1 (YES in S107), in S115, voltage control unit 184 requests a control signal to adjust the output voltage of ISG 30 to 15.0V. SG is output to ECU70. When the ECU 70 receives the control signal SG, the ECU 70 controls the voltage adjustment unit 31 to adjust the output voltage of the ISG 30 to 15.0V. Further, the switch control unit 185 controls the switch element 35 to alternately repeat the on period Ton and the off period Toff of the switch element 35 (for example, Ton = Toff = 5 seconds in the third embodiment). Thereby, the lead storage battery 50 and the nickel metal hydride storage battery 61 of the power supply unit 45 are pulse-charged at a voltage of 15.0V. S109 to S112 are the same as S109 to S112 of FIG. 9 of the second embodiment.

  As described with reference to FIG. 24, in constant voltage charging with a voltage of 15.0 V, the charging current of the lead storage battery 50 is larger than the charging current of the nickel hydride storage battery 61 in the initial period T0 at the beginning of charging. . On the other hand, in the third embodiment, as shown in FIG. 13, the on period Ton and the off period Toff are alternately repeated to turn on and off the switch element 35.

  In the off period Toff of the switch element 35, the voltage is zero. In both the lead storage battery 50 and the nickel metal hydride storage battery 61, the state in the vicinity of the electrode returns to the initial state in about 5 seconds when the application of voltage is stopped. For this reason, for every ON period Ton of the switch element 35, it will be in the same state as the initial period T0 at the beginning of charge of FIG. Therefore, in the ON period Ton of the switch element 35, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61. Therefore, as shown in FIG. 12, in the charging period Tch3, the SOC of the nickel metal hydride storage battery 61 hardly increases and the SOC of the lead storage battery 50 mainly increases. When the SOC value of the lead storage battery 50 reaches the SOC upper limit value Spb2 (eg, Spb2 = 105% in the third embodiment) (YES in S110 of FIG. 11), the switch element 35 is turned off (S111 of FIG. 11). ) Charging is stopped.

  Thus, also in 3rd Embodiment, as FIG. 12 shows, the overcharge which the SOC value of the lead storage battery 50 exceeds 100% is performed. Thereby, also in 3rd Embodiment, it can suppress that the sulfation which arises in the lead storage battery 50 with insufficient charge progresses similarly to 2nd Embodiment. Moreover, also in 3rd Embodiment, the lead storage battery 50 does not deteriorate excessively by overcharge similarly to 2nd Embodiment.

(Modification of the second and third embodiments)
The present invention is not limited to the second and third embodiments. Hereinafter, modifications of the second and third embodiments of the present invention will be described.

  (1) In the third embodiment, in S115 of FIG. 11, the switch control unit 185 of the battery control unit 180 turns on and off the switch element 35 to perform pulse charging. Alternatively, in S115 of FIG. 11, the switch control unit 185 may switch the output voltage of the ISG 30 in a pulsed manner, as shown in FIG.

  FIG. 14 is a timing chart schematically showing the output voltage of the ISG 30. In the operation illustrated in FIG. 14, the voltage control unit 184 sends a control signal SG requesting the ECU 70 to alternately repeat the first period T1 of the output voltage 15.0V and the second period T2 of the output voltage 13.7V. Output. When the ECU 70 receives the control signal SG, the ECU 70 controls the voltage adjusting unit 31 to control the output voltage of the ISG 30 as shown in FIG.

  The second period T2 is, for example, 5 seconds. In the second period T2 where the charging voltage is 13.7 V, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61 as described with reference to FIG. Therefore, in the second period T2, the SOC of the lead storage battery 50 increases faster than the SOC of the nickel metal hydride storage battery 61, as in the charging period Tch1 of FIG. The second period T2 is not limited to 5 seconds, and may be 10 seconds, for example.

  The first period T1 is, for example, 4 seconds. Unlike the off period Toff of the third embodiment (FIG. 13), in the second period T2, the charging voltage is not 0 but 13.7V. Therefore, the period during which the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61 is considered to be shorter than the initial period T0 shown in FIG. Therefore, in the operation of FIG. 14, the first period T1 is set to 4 seconds, for example, and is shorter than the initial period T0 of about 5 seconds.

  Accordingly, even in the first period T1, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61. For this reason, even in the first period T1, the SOC of the lead storage battery 50 increases faster than the SOC of the nickel metal hydride storage battery 61. As a result, also in the operation of FIG. 14, the SOC of the lead storage battery 50 can be charged to the SOC upper limit value Spb2 (for example, Spb2 = 105%), as in the third embodiment (FIG. 12).

  In the charging of FIG. 14, the charging is continued at 13.7 V even in the second period T2, and the on / off of the charging is not repeated alternately as in FIG. Therefore, strictly speaking, the charging in FIG. 14 is not pulse charging. However, in this specification, charging as shown in FIG. 14 is also included in pulse charging.

  (2) In the second embodiment, the output voltage of the ISG 30 is adjusted to 13.7 V in S6 of FIG. In the operation shown in FIG. 14, the output voltage of the ISG 30 in the second period T2 is adjusted to 13.7V. However, it is not limited to 13.7V. The output voltage of the ISG 30 may be adjusted to a voltage at which the hydrogen storage alloy of the negative electrode of the nickel hydride storage battery 61 does not easily store hydrogen, and the lead storage battery 50 is charged. For example, the upper limit may be 1.38 to 1.39 V per cell of the nickel metal hydride storage battery 61. In other words, in this 2nd Embodiment, since the nickel hydride storage battery 61 contains the nickel hydride storage battery of 10 cells connected in series, what is necessary is just to make the output voltage of ISG30 into 13.8-13.9V an upper limit.

  (3) In the second embodiment, the output voltage of the ISG 30 is adjusted to 15.0 V in S8 of FIG. In the operation shown in FIG. 14, the output voltage of the ISG 30 in the first period T1 is adjusted to 15.0V. However, it is not limited to 15.0V. The output voltage of the ISG 30 may be 14.5V, for example. The output voltage of the ISG 30 may be a high voltage at which the ISG 30 can output and the lead storage battery 50 and the nickel metal hydride storage battery 61 are not damaged or failed.

  (4) In the second and third embodiments, the vehicle 1 includes the battery control unit 180 separately from the ECU 70. Alternatively, the ECU 70 may be configured to include each functional block of the battery control unit 180, and the battery control unit 180 may be omitted.

  (5) In the second and third embodiments, the nickel metal hydride storage battery 61 is connected in parallel with the lead storage battery 50. Alternatively, another secondary battery such as a lithium ion secondary battery, a lithium ion polymer secondary battery, or a nickel zinc storage battery may be connected in parallel with the lead storage battery 50.

  (6) In the second and third embodiments, the vehicle 1 includes the ISG 30. Alternatively, a normal alternator may be provided instead of the ISG 30. In this case, the voltage adjustment unit 31 adjusts the output voltage of the alternator.

(Fourth embodiment)
FIG. 15 is a block diagram schematically showing the configuration of the vehicle 1 including the battery control unit 280 and the ECU 70 of the fourth embodiment.

  The vehicle 1 is a hybrid electric vehicle having an engine as a main power source and a motor as an auxiliary power source. The vehicle 1 includes an engine 10, a starter motor 20, an integrated starter generator (ISG) 30, a voltage adjustment unit 31, a switch element 35, an electrical load 40, a power supply unit 45, an electronic control unit (ECU) 70, and a battery control unit 280. .

  The power supply unit 45 includes a lead storage battery 50, current sensors 51 and 63, and a nickel metal hydride storage battery (Ni-MH) 61. The lead storage battery 50 and the nickel metal hydride storage battery 61 are connected in parallel to each other. The connection point K2 on the negative electrode side of the lead storage battery 50 and the nickel hydride storage battery 61 is grounded. The starter motor 20, ISG 30, and electrical load 40 are connected in parallel with the power supply unit 45. A power supply voltage Vcc is supplied from the power supply unit 45 to the battery control unit 280 and the ECU 70.

  The lead storage battery 50 includes a 6-cell lead storage battery connected in series. With this configuration, the nominal voltage of the lead storage battery 50 is 12V. The nickel hydride storage battery 61 includes 10 cells of nickel hydride storage batteries connected in series. With this configuration, the nominal voltage of the nickel metal hydride storage battery 61 is 12V. The electric power output from the power supply unit 45 is used to drive the starter motor 20 and the ISG 30 that start the engine 10 of the vehicle 1 and to power the electrical load 40.

  The current sensor 51 detects a charging current or a discharging current flowing through the lead storage battery 50. The current sensor 51 is attached on the branch line L1 branched from the connection point K1 on the positive electrode side of the lead storage battery 50 and the nickel metal hydride storage battery 61. The current sensor 51 is provided for calculating the charge electricity amount and the discharge electricity amount of the lead storage battery 50.

  The current sensor 63 detects a charging current or a discharging current flowing through the nickel metal hydride storage battery 61. The current sensor 63 is attached on the branch line L2 branched from the connection point K1 on the positive electrode side of the lead storage battery 50 and the nickel hydride storage battery 61. The current sensor 63 is provided for calculating the charge electricity amount and the discharge electricity amount of the nickel metal hydride storage battery 61.

  The current sensors 51 and 63 are, for example, Hall effect type current sensors including Hall elements. Alternatively, the current sensors 51 and 63 may include a shunt resistor and detect a current based on a voltage drop of the shunt resistor.

  The starter motor 20 starts the engine 10 when the ignition switch is operated by the user.

  The ISG 30 has both a power generation function and an electric function. When the engine 10 of the vehicle 1 is operating, the ISG 30 is driven by the engine 10 and generates power by a power generation function. When the generated power exceeds the electrical load of the electrical load 40, the lead storage battery 50 and the nickel hydride storage battery 61 of the power supply unit 45 are charged by the generated power. Further, when a brake pedal (not shown) is operated while the vehicle 1 is traveling and starts decelerating, torque is transmitted from the wheels to the ISG 30, and the ISG 30 generates power by a power generation function. The lead-acid battery 50 and the nickel-metal hydride storage battery 61 of the power supply unit 45 are charged by the generated power. This regenerates energy. When the vehicle 1 stops, the engine 10 is automatically stopped by the idle stop control of the ECU 70. When the vehicle 1 starts, the vehicle 1 is driven by the electric function of the ISG 30 and the engine 10 is started.

  The voltage adjustment unit 31 adjusts the output voltage of the ISG 30. If the output voltage by the power generation function of the ISG 30 is not adjusted, it changes depending on the rotation speed of the engine 10, the current value of the load current, and the field current. The voltage adjustment unit 31 adjusts the output voltage of the ISG 30 to a constant value by increasing or decreasing the field current, for example. The voltage adjustment unit 31 includes, for example, a semiconductor circuit in which a power transistor and a voltage detection circuit are integrated. In the fourth embodiment, the voltage adjusting unit 31 adjusts the output voltage of the ISG 30 to, for example, DC 14.5 V (an example of a charging voltage value).

  The switch element 35 is provided between the ISG 30 and the power supply unit 45. The switch element 35 is turned on when the engine 10 is stopped. The switch element 35 is turned off when charging of the lead storage battery 50 and the nickel metal hydride storage battery 61 is stopped. On / off of the switch element 35 is controlled by the battery control unit 280. The switch element 35 may be a mechanical relay. Alternatively, the switch element 35 may be a semiconductor switch such as a power MOSFET or an insulated gate bipolar transistor. The electrical load 40 includes a load such as an electrical component equipped in the vehicle 1 such as an air conditioner and a room light.

  The ECU 70 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) in which a predetermined control program is stored, a RAM (Random Access Memory) in which data is temporarily stored, these Peripheral circuits are provided. The ECU 70 is configured to be able to communicate with the battery control unit 280.

  The ECU 70 controls the overall operation of the vehicle 1 including the engine 10, the starter motor 20, the ISG 30, the voltage adjustment unit 31, and the electrical load 40.

  The battery control unit 280 includes, for example, a CPU that executes predetermined arithmetic processing, a ROM that stores a predetermined control program, a RAM that temporarily stores data, and peripheral circuits thereof. The battery control unit 280 includes a storage unit 281 configured with, for example, a flash memory. The battery control unit 280 functions as a first SOC calculation unit 282, a second SOC calculation unit 283, and a switch control unit 285 by executing a control program stored in the ROM.

  Storage unit 281 stores in advance an SOC upper limit value Sni2 (an example of a first SOC upper limit value) that is set in advance as the upper limit value of the SOC of nickel-metal hydride storage battery 61. In the fourth embodiment, for example, Sni2 = 80%. The SOC upper limit value Sni2 is not limited to 80%, and may be 75%, for example. As described above, when the SOC upper limit value Sni2 is too high, the nickel-metal hydride storage battery 61 cannot store the regenerative energy of the engine 10. Therefore, the SOC upper limit value Sni2 may be an SOC value that can store the regenerative energy of the engine 10.

  Storage unit 281 stores in advance an SOC lower limit value Sni3 (an example of a first SOC lower limit value) that is set in advance as the lower limit value of the SOC of nickel-metal hydride storage battery 61. In the fourth embodiment, for example, Sni3 = 20%. The SOC lower limit value Sni3 is not limited to 20%, and may be 25%, for example. As described above, if SOC lower limit value Sni3 is too low, it will hinder the supply of a large current required when starting engine 10 or when restarting engine 10 that is stopped by idle stop control. Therefore, the SOC lower limit value Sni3 may be an SOC value that can supply a large current when the engine 10 is started or restarted.

  Storage unit 281 stores in advance a SOC protection threshold value Sni4 that is set to a value that exceeds SOC upper limit value Sni2. In the fourth embodiment, for example, Sni4 = 90%. Note that the SOC protection threshold Sni4 is not limited to 90%, and may be 85%, for example. The SOC protection threshold value Sni4 may be determined so that the SOC value of the nickel metal hydride storage battery 61 does not become excessive.

  Storage unit 281 stores in advance an SOC upper limit value Spb2 (an example of a second SOC upper limit value) that is predetermined as 100% or more as the upper limit value of the SOC of lead-acid battery 50. In the fourth embodiment, for example, Spb2 = 100%.

  Storage unit 281 stores in advance an SOC lower limit value Spb3 (an example of a second SOC lower limit value) that is set in advance as the lower limit value of the SOC of lead-acid battery 50. In the fourth embodiment, for example, Spb3 = 80%. The SOC lower limit value Spb3 is not limited to 80%, and may be 75%, for example. When the SOC value of the lead storage battery 50 becomes excessively low, the deterioration of the lead storage battery 50 is accelerated. Therefore, the SOC lower limit value Spb3 only needs to be determined so that the deterioration of the lead storage battery 50 is not accelerated.

  Battery control unit 280 controls charging and discharging of nickel-metal hydride storage battery 61 such that the SOC of nickel-metal hydride storage battery 61 is maintained within the range of SOC upper limit value Sni2 and SOC lower limit value Sni3. Battery control unit 280 controls charging and discharging of lead storage battery 50 such that the SOC of lead storage battery 50 is maintained at or above SOC lower limit Spb3.

  The first SOC calculation unit 282 calculates the charge electricity amount and the discharge electricity amount of the lead storage battery 50 using the current value detected by the current sensor 51. The first SOC calculation unit 282 calculates the SOC of the lead storage battery 50 using the calculated amount of charge and discharge of the lead storage battery 50. The first SOC calculation unit 282 calculates the SOC every 100 msec, for example. The first SOC calculation unit 282 and the current sensor 51 correspond to an example of a lead storage battery SOC acquisition unit.

  The second SOC calculation unit 283 calculates the charge electricity amount and the discharge electricity amount of the nickel metal hydride storage battery 61 using the current value detected by the current sensor 63. The second SOC calculation unit 283 calculates the SOC of the nickel-metal hydride storage battery 61 using the calculated amount of charge and discharge of the nickel-metal hydride storage battery 61. The second SOC calculation unit 283 calculates the SOC every 100 msec, for example. The second SOC calculation unit 283 and the current sensor 63 correspond to an example of a secondary battery SOC acquisition unit.

  The switch control unit 285 controls on / off of the switch element 35. The switch control unit 285 turns on the switch element 35 when the engine 10 is stopped. When the SOC of the nickel metal hydride storage battery 61 calculated by the second SOC calculation unit 283 increases to the SOC upper limit value Sni2 or more during charging, the switch control unit 285 turns off the switch element 35 and stops charging.

  When the SOC of the lead storage battery 50 calculated by the first SOC calculation unit 282 increases to the SOC upper limit value Spb2 or more during charging, the switch control unit 285 turns off the switch element 35 and stops charging.

  The switch control unit 285 turns on the switch element 35 while the SOC of the nickel-metal hydride storage battery 61 calculated by the second SOC calculation unit 283 is less than the SOC upper limit value Spb2. When the SOC of the nickel metal hydride storage battery 61 calculated by the second SOC calculation unit 283 increases to the SOC upper limit value Spb2 or more during charging, the switch control unit 285 turns on and off the switch element 35 to change from constant voltage charging to pulse charging. Switch.

  FIG. 16 is a flowchart schematically showing the charging operation of the fourth embodiment. FIG. 17 is a diagram schematically showing an example of the SOCs of the lead storage battery 50 and the nickel metal hydride storage battery 61 that are increased by the charging operation of FIG. FIG. 18 is a timing chart schematically showing the operation of the switch element 35.

  The vertical axis in FIG. 17 represents the SOC of the lead storage battery 50, and the horizontal axis represents the SOC of the nickel metal hydride storage battery 61. In FIG. 17, a charging period Tch1 represents a period during which constant voltage charging is performed, and a charging period Tch2 represents a period during which pulse charging is performed. The charging period Tch3 represents a period during which pulse charging is performed in a fifth embodiment to be described later. In the normal state (that is, when the operation of FIG. 16 is started), the switch element 35 is turned on.

  In S201 of FIG. 16, first, the switch control unit 285 acquires the SOC value of the lead storage battery 50 from the first SOC calculation unit 282. The switch control unit 285 determines whether or not the obtained SOC value of the lead storage battery 50 is less than the SOC lower limit value Spb3. If the SOC value of lead storage battery 50 is less than SOC lower limit value Spb3 (YES in S201), switch control unit 285 keeps switch element 35 on in S202 (an example of a predetermined voltage charging step). Thereby, constant voltage charging is performed.

  As described with reference to FIG. 24, when the voltage is 14.5 V, the charging current of the nickel-metal hydride storage battery 61 is larger than the charging current of the lead storage battery 50 except for the initial period T0 at the beginning of charging. Therefore, as shown in FIG. 17, the SOC of the nickel-metal hydride storage battery 61 increases faster than the SOC of the lead storage battery 50 in the charging period Tch1.

  In S203 (an example of a secondary battery SOC acquisition step), the switch control unit 285 acquires the SOC value of the nickel-metal hydride storage battery 61 from the second SOC calculation unit 283. The switch control unit 285 determines whether or not the obtained SOC value of the nickel metal hydride storage battery 61 is equal to or higher than the SOC upper limit value Sni2. If the SOC value of nickel metal hydride storage battery 61 is less than SOC upper limit value Sni2 (NO in S203), the process returns to S202, and constant voltage charging is continued.

  In S203, if the SOC value of the nickel-metal hydride storage battery 61 is greater than or equal to the SOC upper limit value Sni2 (YES in S203), the switch control unit 285 controls the switch element 35 in S204 (an example of a pulse charging step), The on period Ton and the off period Toff of the switch element 35 are alternately repeated (for example, Ton = Toff = 5 seconds in the fourth embodiment). As a result, the lead storage battery 50 and the nickel hydride storage battery 61 of the power supply unit 45 are pulse-charged at a voltage of 14.5V.

  As described with reference to FIG. 24, in constant voltage charging with a voltage of 14.5 V, the charging current of the lead storage battery 50 is larger than the charging current of the nickel metal hydride storage battery 61 in the initial period T0 at the beginning of charging. . On the other hand, in S4, as shown in FIG. 18, the ON period Ton and the OFF period Toff are alternately repeated to turn on and off the switch element 35.

  In the off period Toff of the switch element 35, the voltage is zero. In both the lead storage battery 50 and the nickel metal hydride storage battery 61, the state in the vicinity of the electrode returns to the initial state in about 5 seconds when the application of voltage is stopped. For this reason, for every ON period Ton of the switch element 35, it will be in the same state as the initial period T0 at the beginning of charge of FIG. Therefore, in the ON period Ton of the switch element 35, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61. For this reason, as shown in FIG. 17, in the charging period Tch2, the SOC of the nickel-metal hydride storage battery 61 hardly increases and the SOC of the lead storage battery 50 mainly increases.

  Returning to FIG. 16, in S <b> 205, the switch control unit 285 acquires the SOC value of the nickel-metal hydride storage battery 61 from the second SOC calculation unit 283. The switch control unit 285 determines whether or not the obtained SOC value of the nickel metal hydride storage battery 61 is less than the SOC lower limit value Sni3. If the SOC value of nickel-metal hydride storage battery 61 is equal to or greater than SOC lower limit value Sni3 (NO in S205), in S206, switch control unit 285 determines whether the SOC value of nickel-metal hydride storage battery 61 is greater than or equal to SOC protection threshold value Sni4. Determine whether.

  If the SOC value of the nickel metal hydride storage battery 61 is less than the SOC protection threshold value Sni4 (NO in S206), the switch control unit 285 acquires the SOC value of the lead storage battery 50 from the first SOC calculation unit 282 in S207. Switch control unit 285 determines whether or not the SOC value of lead storage battery 50 is equal to or higher than SOC upper limit Spb2. If the SOC value of lead storage battery 50 is less than SOC upper limit Spb2 (NO in S207), the process returns to S204, and pulse charging is continued.

  In S205, if the SOC value of nickel-metal hydride storage battery 61 is less than SOC lower limit value Sni3 (YES in S205), the process returns to S202. Accordingly, the switch control unit 285 turns on the switch element 35 and switches from pulse charging to constant voltage charging. As a result, the SOC value of the nickel metal hydride storage battery 61 that has decreased below the SOC lower limit value Sni3 increases.

  If the SOC value of the nickel metal hydride storage battery 61 is equal to or greater than the SOC protection threshold value Sni4 in S206 (YES in S206), the switch control unit 285 turns off the switch element 35 and stops pulse charging in S208.

  In S207, when the SOC value of the lead storage battery 50 reaches the SOC upper limit value Spb2 (eg, Spb2 = 100% in the fourth embodiment) (YES in S207), the process proceeds to S208.

  If the SOC value of the lead storage battery 50 is equal to or higher than the SOC lower limit value Spb3 in S201 (NO in S201), the switch control unit 285 acquires the SOC value of the nickel metal hydride storage battery 61 from the second SOC calculation unit 283 in S209. . The switch control unit 285 determines whether or not the obtained SOC value of the nickel metal hydride storage battery 61 is less than the SOC upper limit value Sni2. If the SOC value of nickel-metal hydride storage battery 61 is greater than or equal to SOC upper limit value Sni2 (NO in S209), the process proceeds to S208.

  In S209, if the SOC value of nickel metal hydride storage battery 61 is less than SOC upper limit value Sni2 (YES in S209), the process proceeds to S202.

  As shown in S206 and S207 of FIG. 16, when the SOC value of the nickel-metal hydride storage battery 61 is greater than or equal to the SOC protection threshold Sni4 or the SOC value of the lead storage battery 50 is greater than or equal to the SOC upper limit value, the switch element 35 is turned off. Pulse charging is stopped. In the example of FIG. 17, pulse charging is stopped when the SOC value of the lead storage battery 50 reaches the SOC upper limit Spb2 or more.

  As described above, in the fourth embodiment, as shown in FIG. 17, constant voltage charging is performed until the SOC value of the nickel-metal hydride storage battery 61 reaches 80% in the charging period Tch1, and the lead storage battery 50 in the charging period Tch2. The battery is pulse charged until the SOC value reaches 100%. Thus, according to the fourth embodiment, both the lead storage battery 50 and the nickel metal hydride storage battery 61 can be prevented from being insufficiently charged.

(Fifth embodiment)
19 and 20 are flowcharts schematically showing the charging operation of the fifth embodiment. The configuration of the fifth embodiment is the same as that of the fourth embodiment shown in FIG. Hereinafter, the fifth embodiment will be described focusing on differences from the fourth embodiment.

  In the fifth embodiment, the storage unit 281 stores in advance two values of 100% and a value exceeding 100% (for example, 105% in the fifth embodiment) as the SOC upper limit value Spb2.

  The switch control unit 285 counts the number of times that the SOC of the lead storage battery 50 calculated by the first SOC calculation unit 282 has fallen below the SOC lower limit value Spb3. Every time the count value is N (N = 5, for example, in the fifth embodiment), the switch control unit 285 uses a value exceeding 100% (for example, 105% in the fifth embodiment) as the SOC upper limit value Spb2. . When the count value is 1 to (N−1) times, that is, less than N times, the switch control unit 285 uses 100% as the SOC upper limit value Spb2. The value exceeding 100% is not limited to 105%, and may be 110%, for example, and may be set to an appropriate value according to the characteristics of the lead storage battery 50.

  In FIG. 19, S201 is the same as S201 of FIG. 16 of the fourth embodiment. If the SOC value of the lead storage battery 50 is less than the SOC lower limit value Spb3 (YES in S201), the switch control unit 285 increases the count value Ct by 1 in S211.

  In S212, the switch control unit 285 determines whether or not the count value Ct is less than N (N = 5 in the fifth embodiment). If the count value Ct is less than N (YES in S212), in S213, the switch control unit 285 sets the SOC upper limit value Spb2 to 100%. Subsequently, the process proceeds to S202.

  On the other hand, if the count value Ct is greater than or equal to N in S212 (NO in S212), the switch control unit 285 resets the count value Ct to 0 in S14. In S215, the switch control unit 285 sets the SOC upper limit value Spb2 to 105%. Subsequently, the process proceeds to S202. S202 to S209 are the same as S202 to S209 of FIG. 16 of the fourth embodiment.

  In this way, every time the SOC value of the lead storage battery 50 decreases to less than the SOC lower limit value Spb3 N times, the SOC upper limit value Spb2 is set to 105%. Therefore, if NO in S5 of FIG. 20 and NO in S6, pulse charging is continued until YES in S7. Therefore, as shown in FIG. 17, the lead storage battery 50 has a charge period Tch3 as shown in FIG. The battery is charged until the SOC value reaches 105%.

  According to the fifth embodiment, as shown in the charging period Tch3 of FIG. 17, the lead storage battery 50 is overcharged with an SOC value exceeding 100%. Thereby, it is possible to suppress the sulfation generated in the insufficiently charged lead storage battery 50 from proceeding excessively. The overcharge is not performed every time the SOC value of the lead storage battery 50 falls below the SOC lower limit value Spb3, but the SOC value of the lead storage battery 50 falls to less than the SOC lower limit value Spb3. In the fifth embodiment, for example, N = 5). For this reason, the lead storage battery 50 does not deteriorate excessively due to overcharging.

(Sixth embodiment)
FIG. 21 is a block diagram schematically showing the configuration of the vehicle 1 including the battery control unit 280 and the ECU 70 of the sixth embodiment. Hereinafter, the sixth embodiment will be described focusing on differences from the fourth embodiment.

  In the sixth embodiment, the voltage adjustment unit 31 adjusts the output voltage of the ISG 30 in, for example, two stages of DC 15.0V and DC 13.7V.

  In the sixth embodiment, the battery control unit 280 further includes a voltage control unit 284. The voltage control unit 284 outputs a control signal SG to the ECU 70 to control the charging voltage during charging of the lead storage battery 50 and the nickel metal hydride storage battery 61. The ECU 70 receives the control signal SG output from the battery control unit 280 and controls the voltage adjustment unit 31.

  FIG. 22 is a timing chart schematically showing a charging current when the power supply unit 45 of FIG. 15 is charged at a constant voltage of 13.7V.

  In FIG. 22, unlike FIG. 24 described above, the charging current Ini of the nickel metal hydride storage battery 61 does not exceed the charging current Ipb of the lead storage battery 50. The cause of this is estimated as follows. In the dissolution / precipitation type lead-acid battery 50, even when the voltage is 13.7 V, the chemical reaction of charging proceeds although the speed is low. However, in the nickel metal hydride storage battery 61, since the voltage is too low at 13.7 V, the hydrogen storage alloy does not easily store hydrogen, so that the chemical reaction of charging hardly proceeds. Therefore, when the power supply unit 45 in FIG. 15 is charged at a constant voltage of 13.7 V, the charging current Ipb of the lead storage battery 50 becomes larger than the charging current Ini of the nickel metal hydride storage battery 61.

  As can be seen from a comparison between FIG. 22 and FIG. 24, the total charging current It is about half that of FIG. 24 in FIG. For this reason, it takes time to charge the lead storage battery 50 and the nickel metal hydride storage battery 61. However, when the output voltage of the ISG 30 is adjusted to 13.7 V, the lead storage battery 50 can be charged faster than the nickel metal hydride storage battery 61.

  In S204 in FIG. 16 in the fourth embodiment and in S204 in FIG. 20 in the fifth embodiment, the switch control unit 285 of the battery control unit 280 performs pulse charging by turning on and off the switch element 35. Alternatively, in the sixth embodiment, the voltage control unit 284 switches the output voltage of the ISG 30 in a pulse form as shown in FIG.

  FIG. 23 is a timing chart schematically showing the output voltage of the ISG 30. In the operation shown in FIG. 23, the voltage control unit 284 sends the control signal SG requesting the ECU 70 to alternately repeat the first period T1 of the output voltage 15.0V and the second period T2 of the output voltage 13.7V. Output. When the ECU 70 receives the control signal SG, the ECU 70 controls the voltage adjusting unit 31 to control the output voltage of the ISG 30 as shown in FIG.

  The second period T2 is, for example, 5 seconds. In the second period T2 where the charging voltage is 13.7 V, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61 as described with reference to FIG. Therefore, in the second period T2, the SOC of the lead storage battery 50 increases faster than the SOC of the nickel metal hydride storage battery 61, as in the charging period Tch2 of FIG. The second period T2 is not limited to 5 seconds, and may be 10 seconds, for example.

  The first period T1 is, for example, 4 seconds. Unlike the off period Toff in the fourth embodiment (FIG. 18), the charging voltage is not 0 but 13.7 V in the second period T2. Therefore, the period during which the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61 is considered to be shorter than the initial period T0 shown in FIG. Therefore, in the operation of FIG. 23, the first period T1 is set to 4 seconds, for example, and is shorter than the initial period T0 of about 5 seconds.

  Accordingly, even in the first period T1, the charging current Ipb of the lead storage battery 50 is larger than the charging current Ini of the nickel metal hydride storage battery 61. For this reason, even in the first period T1, the SOC of the lead storage battery 50 increases faster than the SOC of the nickel metal hydride storage battery 61. As a result, also in the operation of FIG. 23, the SOC of the lead storage battery 50 is set to the SOC upper limit value Spb2 (Spb2 = 100% in the fourth embodiment, Spb2 = 105 in the fifth embodiment), as in the fourth and fifth embodiments. %) Can be charged.

  In the charging of FIG. 23, the charging is continued at 13.7 V even in the second period T2, and the on / off of the charging is not repeated alternately as shown in FIG. Therefore, strictly speaking, the charging in FIG. 23 is not pulse charging. However, in this specification, charging as shown in FIG. 23 is also included in pulse charging.

(Modification of the fourth to sixth embodiments)
The present invention is not limited to the fourth to sixth embodiments. Hereinafter, modified embodiments of the fourth to sixth embodiments of the present invention will be described.

  (1) In the sixth embodiment, the output voltage of the ISG 30 in the second period T2 is adjusted to 13.7V. However, it is not limited to 13.7V. The output voltage of the ISG 30 may be adjusted to a voltage at which the hydrogen storage alloy of the negative electrode of the nickel hydride storage battery 61 does not easily store hydrogen, and the lead storage battery 50 is charged. For example, the upper limit may be 1.38 to 1.39 V per cell of the nickel metal hydride storage battery 61. In other words, in this 4th Embodiment, since the nickel hydride storage battery 61 contains the nickel hydride storage battery of 10 cells connected in series, what is necessary is just to make the output voltage of ISG30 into 13.8-13.9V an upper limit.

  (2) In the fourth embodiment, the output voltage of the ISG 30 is adjusted to 14.5V. In the sixth embodiment, the output voltage of the ISG 30 in the first period T1 is adjusted to 15.0V. However, it is not limited to these voltage values. The output voltage of the ISG 30 may be a high voltage at which the ISG 30 can output and the lead storage battery 50 and the nickel metal hydride storage battery 61 are not damaged or failed.

  (3) In the fourth to sixth embodiments, the vehicle 1 includes the battery control unit 280 separately from the ECU 70. Alternatively, the ECU 70 may be configured to include each functional block of the battery control unit 280, and the battery control unit 280 may be omitted.

  (4) In the fourth to sixth embodiments, the nickel hydride storage battery 61 is connected in parallel with the lead storage battery 50. Alternatively, another secondary battery such as a lithium ion secondary battery, a lithium ion polymer secondary battery, or a nickel zinc storage battery may be connected in parallel with the lead storage battery 50.

  (5) In the fourth to sixth embodiments, the vehicle 1 includes the ISG 30. Alternatively, a normal alternator may be provided instead of the ISG 30. In this case, the voltage adjustment unit 31 adjusts the output voltage of the alternator.

The degradation determination apparatus for a lead storage battery and the degradation determination method for a lead storage battery according to the present disclosure are useful as an apparatus and a method that can suitably determine the degradation of the lead storage battery. In addition, the charging control device and the charging control method according to the present disclosure are useful as a device and a method that can suitably charge lead storage batteries and secondary batteries connected in parallel to each other.

Claims (21)

A power supply unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel with each other;
A voltage detection unit for detecting a voltage of the power supply unit;
An acquisition unit for acquiring an internal resistance of the secondary battery;
A storage unit for preliminarily storing an entire current value supplied from the power supply unit to the starter motor when the engine is started by the starter motor;
The voltage detecting unit detects a starting voltage, which is a voltage of the power supply unit when the engine is started by the starting motor, and the detected starting voltage and the inside of the secondary battery acquired by the acquiring unit A calculation unit that calculates an internal resistance of the lead-acid battery using a resistance and the overall current value stored in the storage unit;
When the internal resistance of the lead storage battery calculated by the arithmetic unit is compared with a predetermined resistance threshold, and the internal resistance of the lead storage battery is higher than the resistance threshold, the lead storage battery is deteriorated. A determination unit for determining;
Comprising
Lead storage battery deterioration judgment device. When the determination unit determines that the lead storage battery is deteriorated, the automatic stop of the engine by idle stop control is prohibited.
The deterioration determination apparatus for a lead storage battery according to claim 1. The starting motor is a motor that starts the engine that is automatically stopped by the idle stop control.
The deterioration determination apparatus for a lead storage battery according to claim 2. The starting motor is a motor that starts the engine by an operation of an ignition switch by a user.
The deterioration determination apparatus for a lead storage battery according to claim 1. A deterioration determination method for a lead storage battery in a deterioration determination apparatus for a lead storage battery including a power supply unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel with each other,
An obtaining step for obtaining an internal resistance of the secondary battery;
A detection step of detecting a starting voltage which is a voltage of the power source when the engine is started by the starting motor;
The starting voltage detected in the detecting step, the internal resistance of the secondary battery acquired in the acquiring step, and the starting motor is supplied from the power supply unit to the starting motor when the engine is started. A calculation step for calculating an internal resistance of the lead storage battery using an overall current value,
When the internal resistance of the lead storage battery calculated in the calculation step is compared with a predetermined resistance threshold, and the internal resistance of the lead storage battery is higher than the resistance threshold, the lead storage battery is deteriorated. A determination step for determining;
including,
Deterioration judgment method of lead acid battery. A power supply unit including a lead-acid battery and a secondary battery other than the lead-acid battery connected in parallel with each other;
A charge control unit for charging the lead storage battery and the secondary battery of the power supply unit by constant voltage charging at a predetermined voltage value determined in advance;
With
In the initial period at the beginning of charging at the predetermined voltage value, the predetermined voltage value is such that the charge current of the lead storage battery is larger than the charge current of the secondary battery, and after the initial period, the lead storage battery The charging current of the secondary battery is preset to a value that is larger than the charging current of
Charge control device. A first SOC acquisition unit for acquiring the SOC of the lead storage battery;
A storage unit for storing an SOC threshold value of 100% or less predetermined as the SOC of the lead storage battery;
A voltage adjustment unit for adjusting a charging voltage to the predetermined voltage value or a predetermined low voltage value lower than the predetermined voltage value;
Further comprising
The charge control unit controls the voltage adjustment unit to adjust the charge voltage to the predetermined low voltage value until the SOC of the lead storage battery acquired by the first SOC acquisition unit reaches the SOC threshold value. Then, after the SOC of the lead storage battery reaches the SOC threshold, the lead storage battery and the secondary battery of the power supply unit are charged by two-stage constant voltage charging for adjusting the charging voltage to the predetermined voltage value,
The predetermined low voltage value is predetermined to a value at which the charging current of the lead storage battery is larger than the charging current of the secondary battery,
The charge control device according to claim 6. A second SOC acquisition unit for acquiring the SOC of the secondary battery;
The storage unit stores a first SOC upper limit value less than 100%, which is predetermined as the SOC of the secondary battery,
The charge control unit stops the two-stage constant voltage charging when the SOC of the secondary battery acquired by the second SOC acquisition unit reaches the first SOC upper limit value.
The charge control device according to claim 7. The charging control unit increases the SOC threshold value as the SOC of the secondary battery at the start of charging acquired by the second SOC acquisition unit increases.
The charge control device according to claim 8. The storage unit stores a second SOC upper limit value exceeding 100% predetermined as the SOC of the lead storage battery,
The charge control unit stops the two-stage constant voltage charging when the SOC of the lead storage battery reaches the second SOC upper limit value.
The charge control device according to any one of claims 7 to 9. The storage unit stores an SOC lower limit value lower than the SOC threshold predetermined as the SOC of the lead storage battery,
The charge controller is
When the SOC of the lead storage battery falls below the lower limit of the SOC, the number of times of reduction is counted,
Charge the lead storage battery and the secondary battery of the power supply unit by the two-stage constant voltage charging every predetermined number of times counted,
When the counted number is less than the predetermined number, the charging voltage is adjusted to the predetermined voltage value, and the lead storage battery and the secondary battery of the power supply unit are charged at a constant voltage.
The charge control device according to claim 10. In the two-stage constant voltage charging, the charge control unit adjusts the charge voltage to the predetermined voltage value when the SOC of the lead storage battery reaches the SOC threshold value, and the lead storage battery and the secondary battery of the power supply unit A pulse charge with an on period of a length equal to or shorter than the initial period
The charge control device according to any one of claims 7 to 11. A secondary battery SOC acquisition unit for acquiring the SOC of the secondary battery;
A storage unit for storing a first SOC upper limit value less than 100% predetermined as the SOC of the secondary battery;
Further comprising
The charge control unit is configured to charge the lead of the power supply unit by constant voltage charging at the predetermined voltage value while the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is less than the first SOC upper limit value. When the storage battery and the secondary battery are charged, and the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is equal to or higher than the first SOC upper limit value, a predetermined ON period and OFF from the constant voltage charging Switching to pulse charging that repeats the period alternately,
The charge control device according to claim 6. The charging control unit predetermines the on period to a length equal to or shorter than the initial period.
The charge control device according to claim 13. The storage unit stores a predetermined SOC protection threshold value that is less than 100% and exceeds the first SOC upper limit value as the SOC of the secondary battery,
The charge control unit stops the pulse charging when the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is equal to or higher than the SOC protection threshold value during the pulse charging.
The charge control device according to claim 13 or 14. The storage unit stores a predetermined first SOC lower limit value lower than the first SOC upper limit value as the SOC of the secondary battery,
The charge control unit switches the pulse charge to the constant voltage charge when the SOC of the secondary battery acquired by the secondary battery SOC acquisition unit is less than the first SOC lower limit value during the pulse charge.
The charge control device according to any one of claims 13 to 15. A lead storage battery SOC acquisition unit for acquiring the SOC of the lead storage battery;
The storage unit stores a second SOC upper limit value that is predetermined as 100% or more as the SOC of the lead storage battery,
When the SOC of the lead storage battery acquired by the lead storage battery SOC acquisition unit is equal to or higher than the second SOC upper limit value during the pulse charge, the charge control unit stops the pulse charge.
The charge control device according to any one of claims 13 to 16. The storage unit stores 100% and a value exceeding 100% as the second SOC upper limit value, and stores a second SOC lower limit value that is predetermined as less than 100% as the SOC of the lead storage battery,
The charge controller is
When the SOC of the lead storage battery falls below the second SOC lower limit value, the number of times of reduction is counted and the constant voltage charging is started.
Using the value exceeding 100% as the second SOC upper limit value for each predetermined number of times counted,
When the counted number is less than the predetermined number, 100% is used as the second SOC upper limit value.
The charge control device according to claim 17. A charge control method for a charge control device comprising a power storage unit including a lead storage battery and a secondary battery other than the lead storage battery connected in parallel to each other, and controlling charging of the lead storage battery and the secondary battery of the power supply unit. ,
A predetermined voltage charging step of charging the lead storage battery and the secondary battery of the power supply unit at a constant voltage with a predetermined voltage value determined in advance;
Including
In the initial period at the beginning of charging at the predetermined voltage value, the predetermined voltage value is such that the charge current of the lead storage battery is larger than the charge current of the secondary battery, and after the initial period, the lead storage battery The charging current of the secondary battery is preset to a value that is larger than the charging current of
Charge control method. A lead storage battery SOC acquisition step for acquiring the SOC of the lead storage battery;
Until the SOC of the lead storage battery reaches a predetermined SOC threshold value of 100% or less, the lead storage battery and the secondary battery of the power supply unit are charged at a constant voltage with a predetermined low voltage value lower than the predetermined voltage value. A low voltage charging step;
Further including
The predetermined voltage charging step is performed after the SOC of the lead storage battery reaches the SOC threshold,
The predetermined low voltage value is predetermined to a value at which the charging current of the lead storage battery is larger than the charging current of the secondary battery,
The charge control method according to claim 19. A secondary battery SOC acquisition step for acquiring the SOC of the secondary battery;
When the SOC of the secondary battery acquired in the secondary battery SOC acquisition step is equal to or higher than a predetermined first SOC upper limit value of less than 100%, the power source is supplied by pulse charging that repeats a predetermined ON period and OFF period. Pulse charging step of charging the lead storage battery and the secondary battery,
Further including
The predetermined voltage charging step is executed while the SOC of the secondary battery acquired in the secondary battery SOC acquisition step is less than the first SOC upper limit value.
The charge control method according to claim 19.

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