WO2017158765A1 - Power supply system and automobile - Google Patents

Abstract

Provided is a power supply system which is low-cost and has high utilization efficiency with respect to supplied power. The power supply system 10 is provided with: a combined electricity storage device 10 (Pb battery and NiZn battery); a switching unit 5 for switching the charge/discharge current of the device 10; and a control unit 6 for controlling the switching unit 5 on the basis of the SOC of the NiZn battery. The control unit 6 controls the switching unit 5 so as to, when receiving regenerative power from an alternator 12, charge the Pb battery after charging the NiZn battery up to a use limit SOC prior to and/or together with charging the Pb battery, and, when discharging to a discharge load 14, discharge the Pb battery after discharging the NiZn battery down to a first SOC.

Description

Power supply system and automobile

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system and an automobile, and more particularly, to a power supply system including an electricity storage device that can receive supplied power and discharge to a discharge load, and an automobile including the power supply system.

Conventionally, a power supply system equipped with an electricity storage device that can accept supplied power and can be discharged to a discharge load has been put to practical use in a wide range. This type of power supply system is roughly divided into a stationary type and a mobile type. In recent years, stationary power supply systems in wind power generation and solar power generation have attracted technical attention. On the other hand, mobile type power systems have a long history of development, and are currently more widely spread than stationary type power systems. Typically, a power supply system using a lead storage battery mounted on a moving body (vehicle) such as an automobile can be given. In the following, the recent background art will be described by taking a vehicular power supply system with significant technological competition as an example.

Regular gasoline vehicles charge power storage devices such as lead-acid batteries while power is being supplied from the alternator during traveling except during braking, and keep the power storage devices almost fully charged. In recent years, vehicles (ISS vehicles) having an idling stop system (ISS) function are gradually increasing in such gasoline vehicles from the viewpoint of suppressing carbon dioxide emissions.

In ISS vehicles, the engine is stopped when the vehicle stops. Accordingly, charging from the alternator to the power storage device is also stopped. In the meantime, all power supply to auxiliary equipment such as lamps and electrical equipment is covered by the electricity storage device. Furthermore, at the start after idling stop, the starter (cell motor) is driven by the electric power stored in the power storage device to start the engine. Therefore, in the ISS vehicle, the engine is stopped when the vehicle is stopped, so that the fuel consumption is improved as compared with the ordinary gasoline vehicle.

Recently, the need for fuel efficiency improvement is particularly high due to the increase in the retail price of gasoline. In addition, the number of vehicles with high fuel efficiency is increasing significantly. In accordance with such a situation, an automobile (manufacturing) company has been developing an alternator regenerative vehicle that charges an electricity storage device with regenerative power supplied from an alternator. Such alternator regenerative vehicles include vehicles having the above-described ISS function. Such vehicles are sometimes called μHEVs or microhybrids.

In the alternator regenerative vehicle, the electricity storage device is charged with regenerative power supplied from the alternator, which was consumed by heat in a regular gasoline vehicle. In addition, the operation of the alternator is basically stopped during traveling except during braking, that is, charging of the power storage device is stopped. Thereby, the gasoline consumption by the engine for operating the alternator is reduced, and the fuel consumption is improved. All power supply to the discharge load while the alternator is stopped is covered by the electricity storage device. In μHEV, when the state of charge (SOC) of the power storage device is equal to or lower than a preset value, the alternator is operated during or before traveling to store power in order to prevent overdischarge of the power storage device. Charge your device.

In such a power supply system mounted on an alternator regenerative vehicle, various researches and developments including the storage device itself and control technology have been made in order to receive regenerative power supplied from the alternator. For example, Non-Patent Document 1 discloses a technique for improving charge / discharge characteristics and extending the life of a lead storage battery. Patent Document 1 discloses a power supply system including a composite power storage device that includes a water-based lead storage battery (Pb battery) and a non-aqueous lithium ion battery. Furthermore, at the time of filing of the present application, a power supply system including a composite power storage device composed of a water-based Pb battery and a nickel hydride storage battery (NiMH battery) is mounted on the vehicle.

Japanese Patent Laid-Open No. 2003-13489

By the way, with a Pb battery alone, the chargeable current (about 120 A) is small (low charge acceptance), and it is difficult to recover all the regenerative power during braking. For this reason, in the technique of Patent Document 1, a composite power storage device in which a Pb battery and a lithium ion battery excellent in charge acceptability are combined is used. However, the lithium ion battery constituting the composite power storage device has problems in terms of cost and safety because it uses a non-aqueous electrolyte. In contrast, a composite power storage device combining a Pb battery and a NiMN battery is excellent in this respect. However, NiMN batteries have another problem of low energy density and large self-discharge.

On the other hand, a nickel zinc storage battery (NiZn battery) is conventionally known as a battery having excellent charge acceptance and high energy density and low self-discharge. Further, the NiZn battery is superior in cost to the lithium ion battery in the same manner as the NiMN battery, and is excellent in safety because an aqueous electrolyte is used. NiZn batteries have been lagging in popularity as storage batteries because they are inferior in terms of cycle life due to dendrites. Recently, research and development of NiZn batteries that suppress dendrite and have a long cycle life have been rapidly advanced. For this reason, if the power supply system provided with the composite electrical storage device of a Pb battery and a NiZn battery can be provided, the various subject mentioned above besides the fuel consumption improvement can also be solved.

In view of the above cases, an object of the present invention is to provide a power supply system that is low in cost, excellent in energy density and safety, and highly efficient in use with respect to supplied power, and an automobile equipped with the power supply system.

In order to solve the above-mentioned problems, a first aspect of the present invention is a power supply system, which has a lead storage battery (Pb battery) and a nickel zinc storage battery (NiZn battery), and can accept supply power and discharge load. A storage device that can be discharged at a time, a switching device that switches charging / discharging currents of the Pb battery and the NiZn battery, a state of charge (SOC) of the NiZn battery, and a control of the switching device based on the estimated SOC And when the power storage device accepts the supplied power, the controller charges the NiZn battery up to a use upper limit SOC prior to the Pb battery and / or with the Pb battery. When the battery is charged and the electricity storage device is discharged to the discharge load, the NiZn battery is After discharged to the SOC, discharged from the Pb battery, characterized in that said controlling the switching device to.

The first aspect includes a vehicle power supply system. That is, the supplied power is regenerative power supplied from an alternator, and the power supply system may be a vehicle power supply system.

In such a vehicle power supply system, when the power storage device accepts regenerative power, the controller either charges (a) the NiZn battery to the upper limit SOC and then charges the Pb battery, or (b) determines the NiZn battery in advance. And then charging both the NiZn battery and the Pb battery and charging the NiZn battery to the upper limit SOC and charging the Pb battery, or (c) charging both the NiZn battery and the Pb battery. You may make it control a switching device so that a Pb battery may be charged after charging a NiZn battery to use upper limit SOC.

At this time, it is preferable that the difference between the second SOC and the first SOC is set to 60% or more in order to increase the utilization efficiency of the regenerative power by the power storage device. For example, the first SOC may be set to be less than the second SOC and 10% or more, and the second SOC may be set to a range of 70% to 90%.

Further, the controller acquires regeneration start information indicating that the supply of regenerative power by the alternator starts from the vehicle side and regeneration end information indicating that supply of regenerative power by the alternator ends, and acquires the regeneration start information. In addition, when charging the NiZn battery or Pb battery with regenerative power is started and the regeneration end information is acquired, the charging of the NiZn battery or Pb battery with regenerative power is stopped and the NiZn battery is discharged to the discharge load. Alternatively, the switching device may be controlled.

Furthermore, a conversion device that is inserted between the switching device and the NiZn battery and converts the voltage of the regenerative power may be provided. At this time, the switching device includes a first switch for turning on / off the connection between the alternator and the discharge load and the Pb battery, and a second switch for turning on / off the connection between the alternator and the conversion device, You may have the 3rd switch for turning ON / OFF the connection of a discharge load and a NiZn battery.

Further, in order to suppress the deterioration of the electricity storage device, the NiZn battery is configured by connecting a plurality of single cells in series, and the controller is configured to configure a plurality of NiZn batteries when the electricity storage device is discharged to a discharge load. The switching device may be controlled to discharge from the Pb battery after any of the single cells is discharged until reaching the first SOC. At this time, it is desirable that the first SOC is set to be less than the use upper limit SOC and 10% or more.

Further, the Pb battery is a storage battery for starting the engine, and the controller estimates the SOC of the Pb battery and switches the Pb battery to charge the Pb battery when the Pb battery is discharged to a predetermined third SOC. May be controlled. At this time, it is desirable that the third SOC is set to be less than the upper limit SOC and 70% or more.

Further, in the vehicle power supply system, the conversion device may have a DC step-down circuit or a DC step-up circuit. The NiZn battery may be, for example, an assembled battery in which single cells are connected in 7 series or 8 series.

In order to solve the above-mentioned problem, a second aspect of the present invention is an automobile provided with the power supply system of the first aspect.

According to the present invention, since the electricity storage device is composed of the Pb battery and the NiZn battery, the controller is excellent in energy density and safety at low cost. When the electricity storage device accepts the supplied power, the controller uses the NiZn battery as the upper limit SOC. Until the Pb battery is charged prior to and / or with the Pb battery, the Pb battery is charged, and the NiZn battery is discharged to a predetermined first SOC when the electricity storage device is discharged to a discharge load. Since the switching device is controlled so that it discharges from the battery, the power stored in the NiZn battery can be discharged to the discharge load without waiting for the charging / discharging pause, thus improving the utilization efficiency of the supplied power with respect to the supplied power The effect of being able to be obtained can be obtained.

1 is a block circuit diagram of a power supply system according to a first embodiment to which the present invention is applicable. It is explanatory drawing which shows typically the mounting position of the power supply system of 1st Embodiment in an alternator regeneration vehicle. It is explanatory drawing which shows the detail of the charging / discharging switching part of the power supply system of 1st Embodiment. It is a flowchart of the charging / discharging control routine which CPU of the microcontroller of the control part of the power supply system of 1st Embodiment performs. 6 is a flowchart of a main battery charging process subroutine showing details of step 216 in FIG. 4. It is explanatory drawing which shows typically the charge condition of the electrical storage device which comprises the power supply system of 1st Embodiment, FIG. 6 (A) shows the charge state of a sub battery, FIG.6 (B) shows the charge state of a main battery. . It is a flowchart of the charging / discharging control routine which CPU of the microcontroller of the control part of the power supply system of 2nd Embodiment performs. It is a flowchart of the charging / discharging control routine which CPU of the microcontroller of the control part of the power supply system of 3rd Embodiment performs.

[First Embodiment]
Hereinafter, a first embodiment in which the present invention is applied to a power supply system that can be mounted on an alternator regenerative vehicle will be described with reference to the drawings.

(Vehicle side configuration)
First, before referring to the power supply system of the present embodiment, the main configuration of an alternator regenerative vehicle (μHEV) related to the power supply system will be briefly described. Note that μHEV refers to a gasoline vehicle or a diesel vehicle that has an ISS function, can receive regenerative power supplied from an alternator, and includes an electricity storage device that can discharge to a discharge load.

<Vehicle control unit 16>
As shown in FIG. 1, the alternator regenerative vehicle 20 includes a vehicle control unit (ECU) 16 that controls the operation of the alternator regenerative vehicle 20 as a whole. The vehicle control unit 16 grasps whether an ignition switch (not shown) (hereinafter abbreviated as IGN) is located in an OFF position, an ON / ACC position, or a START position. Moreover, the vehicle control part 16 grasps | ascertains operating states, such as an accelerator, a brake, an engine, speed, acceleration, and other vehicle states, and performs traveling control according to the grasped state.

Further, the vehicle control unit 16 communicates with the control unit of the power supply system via the communication line 18 to receive notification of the state information of the power storage device that constitutes the power supply system, and the vehicle state information ( IGN position information and alternator operation information). The operation information of the alternator includes regeneration start information, regeneration end information, and alternator start information, as will be described later.

<Alternator 12>
The alternator regenerative vehicle 20 includes an alternator 12 that converts the rotational force of the engine (not shown) into (regenerative) electric power when braking or when the accelerator is off. In the present embodiment, the output voltage of the alternator 12 is set to 14V. As will be described later, depending on the state of the power storage device (main battery 1 described later), the alternator 12 may generate power other than when regenerative power is received.

The alternator 12 includes a power generation unit composed of a stator and a rotor, a rectification unit that converts AC power generated by the power generation unit into DC power, and a voltage for making the voltage of the DC power converted by the rectification unit constant. And a regulator. Note that one end of the alternator 12 is connected to a ground (the same potential as the vehicle chassis; hereinafter abbreviated as GND). The other end is connected to one end of a discharge load 14 to be described later and one end of the charge / discharge switching unit 5.

<Discharge load 14>
Further, the alternator regenerative vehicle 20 has a discharge load 14 composed of a starter (cell motor) and an auxiliary machine (not shown). Examples of the auxiliary machine include a lamp (light), an engine pump (spark plug), an air conditioner, a fan, a radio, a television, a CD player, and a car navigation system. The other end of the discharge load 14 is connected to GND. The auxiliary machine may be supplied with a minimum voltage (for example, 8V) for operation from the main battery or the sub battery.

In addition, when the engine of the alternator regenerative vehicle 20 is started, if the IGN is positioned at the START position, electric power is supplied from the power storage device (main battery 1 described later) to the starter, and the starter rotates. The rotation driving force of the starter is transmitted to the rotation shaft of the engine via a clutch mechanism (not shown) to start the engine.

(Power system configuration)
Next, the power supply system 10 of this embodiment is demonstrated. For example, as shown in FIG. 2, the power supply system 10 is mounted in the engine room of the alternator regenerative vehicle 20, but the present invention is not limited to this.

As shown in FIG. 1, the power supply system 10 of the present embodiment includes a power storage device that can accept regenerative power supplied from an alternator 12 and can discharge to a discharge load 14. The power storage device is configured as a composite power storage device of a main battery 1 (Pb battery) and a sub battery 2 (NiZn battery), and constitutes a 14V system power supply system. In the present embodiment, “main battery” refers to a battery for starting the engine, and “sub battery” refers to other batteries.

<Main battery 1>
As the battery case of the main battery 1, a monoblock battery case is used in which six cell chambers are defined by partition walls that partition the inside. A sensor insertion hole is formed in the central partition of the monoblock battery case from the upper side to the substantially central part. A temperature sensor such as a thermistor for detecting the temperature of the central portion of the main battery 1 is inserted into the sensor insertion hole. The temperature sensor is fixed in the sensor insertion hole with an adhesive.

Each cell chamber of the main battery 1 accommodates one set of electrode plates in which a plurality of positive and negative electrode plates are stacked via a separator, and is poured with dilute sulfuric acid as an aqueous electrolyte. . Lead dioxide can be used for the positive electrode active material of the main battery 1, and spongy lead can be used for the negative electrode active material. Further, in order to make the structure easy to accept regenerative power, as disclosed in Non-Patent Document 1, the negative electrode active material mixture includes a negative electrode containing lignin and carbon in addition to the negative electrode active material described above. The agent is mixed.

Each cell chamber is sealed with a lid that integrally covers the opening of the monoblock battery case. The cell chambers are connected in series by a conductive connecting member. At the upper diagonal position of the main battery 1, a positive terminal and a negative terminal that are external output terminals are provided upright. The nominal voltage of each cell is 2V, for example, and the nominal voltage of the main battery 1 is 12V, for example. Note that the negative terminal of the main battery 1 is connected to GND.

<Sub battery 2>
On the other hand, the sub-battery 2 is composed of an assembled battery in which seven nickel zinc single batteries (for example, a nominal voltage of 1.65 V and a full charge voltage of 1.9 V) are connected in series. The sub battery 2 has a positive electrode terminal on the highest potential side and a negative electrode terminal on the lowest potential side, and the negative electrode terminal is connected to GND. The nominal voltage of the sub-battery 2 of this embodiment is 11.55V ((1.65V / cell) × 7), and the full charge voltage is 13.3V ((1.9V / cell) × 7). . Instead of this, an assembled battery in which eight unit cells are connected in series may be used.

It is preferable that the full charge voltage of the sub battery 2 is in a range of about ± 10% with respect to the full charge voltage of the main battery 1. Within this range, even if the selector 5 switches between the sub battery 2 and the main battery 1, it is possible to prevent a sense of incongruity due to, for example, a change in radio volume or a change in light brightness. Among these single cells, a temperature sensor such as a thermistor is fixed to the surface of the single battery cell arranged at the center by an adhesive.

Each cell has an electrode group in which a negative electrode mainly composed of zinc and a positive electrode mainly composed of nickel hydroxide are laminated or wound via a microporous separator. The electrode group is infiltrated with an aqueous electrolyte such as potassium hydroxide and is accommodated in a rectangular, cylindrical, or flat cylindrical battery can. Details of such a single cell are disclosed in, for example, Japanese Patent Application Laid-Open No. 7-6758, Japanese Patent Application Publication No. 2008-539559, Japanese Patent Application Publication No. 2013-507752, and the like.

In order to extend the cycle life, it is necessary to change the shape of the negative electrode, agglomerate, suppress dendrite, improve the conductivity of the negative electrode, and the like. For example, to suppress morphological change, aggregation, and dendrite, calcium, hydroxide, fluoride, phosphoric acid is added to the negative electrode active material, or phosphoric acid, fluoride, carbonate is added to the electrolyte. This can be dealt with by using a polyolefin microporous membrane for the separator. The improvement of the conductivity of the negative electrode can be dealt with by adding bismuth, lead, carbon or the like to the negative electrode active material.

<Charge / discharge switching unit 5>
As shown in FIG. 1, the power supply system 10 includes a charge / discharge switching unit 5 (switch means) as a switching device that switches charge / discharge currents of the main battery 1 and the sub battery 2. The other first end of the charge / discharge switching unit 5 is connected to the main battery 1, the other second end is connected to the input side of the voltage converter 9, and the other third end is connected to the positive terminal of the sub battery 2. . The charge / discharge switching unit 5 includes a plurality of switching elements (for example, power MOSFETs) that can be energized with a large current.

As shown in FIG. 3, the charge / discharge switching unit 5 includes a first switch SW <b> 1 for turning on / off the connection between the alternator 12 and the discharge load 14 and the positive terminal of the main battery 1, the alternator 12, and the voltage conversion unit. 9 has a second switch SW2 for turning on / off the connection with the battery 9, and a third switch SW3 for turning on / off the connection between the discharge load 14 and the positive terminal of the sub battery 2. Hereinafter, these switches are collectively referred to as switches SW1 to SW3.

Here, the function of the charge / discharge switching unit 5 will be described. When the charge / discharge switching unit 5 receives the regenerative power supplied from the alternator 12 by the power storage device, either the main battery 1 or the sub-battery 2 from the alternator 12 (this embodiment) or both (second, which will be described later). It plays the role of a switch connected to the third embodiment). Further, when discharging from the electricity storage device to the discharge load 14, it plays a role of a switch connected to the discharge load 14 from either the main battery 1 or the sub battery 2.

In the present embodiment, as shown in Table 1 below, the charge / discharge switching unit 5 takes five states. That is, all of the switches SW1 to SW3 are turned off, and the alternator 12 / discharge load 14 is not connected to any of the main battery 1, the voltage converter 9 and the sub battery 2, and the first switch SW1 is On state, second switch SW2 and third switch SW3 are turned off and alternator 12 is connected to main battery 1, state "1", second switch SW2 is on, first switch SW1 and first switch SW1 3 in which the switch SW3 is turned off and the alternator 12 is connected to the sub-battery 2 via the voltage converter 9, the third switch SW3 is turned on, the first switch SW1 and the second switch The state “4” in which SW2 is turned off and the sub battery 2 is connected to the discharge load 14, the first switch SW1 is turned on, and the second switch is turned on. Chi SW2 and the third switch SW3 is take one of the states "5" main battery 1 is turned off is connected to the discharge load 14.

Note that the state “1” and the state “5” are different between charging and discharging, but the on / off states of the switches SW1 to SW3 are the same. In this embodiment, as is clear from Table 1, control is performed so that any one of the switches SW1 to SW3 is turned on and any two are turned off during charging and discharging.

When switching the switches constituting the charge / discharge switching unit 5, a state where power is not supplied to the discharge load 14 occurs momentarily. Even in such a case, the following methods (1) to (3) can be cited as methods for supplying power to the discharge load 14. (1) A capacitor is arranged in parallel with the main battery 1 (see FIG. 1). (2) A state in which the main battery 1 and the sub battery 2 are simultaneously connected for a moment is provided (the first switch SW1 and the third switch SW3 are turned on for a moment at the time of discharging). (3) A primary battery or a secondary battery other than the main battery 1 and the sub battery 2 is disposed.

When adopting the above method (1), the voltage of the main battery 1 and the sub battery 2 is set to be equal to or higher than the minimum voltage for operating the auxiliary machine. Here, the capacitance of the capacitor to be used is preferably larger than, for example, a value calculated as follows.

For example, when the time when the main battery 1 and the sub battery 2 are switched (control time by the microcontroller + switching time of the charge / discharge switching unit 5) = X [μs] and load current = Y [A]
I × t = Y × X × 10 ⁻⁶ [C]
From Q = CV,
Y × X × 10 ⁻⁶ = C (Voltage of main battery 1 or sub battery 2 (battery connected before switching) −minimum voltage because the auxiliary machine operates)
Therefore, C = Y × X × 10 ⁻⁶ / (Voltage of main battery 1 or sub battery 2 (battery connected before switching) −minimum voltage because the auxiliary machine operates) Use a capacitor of [F] or more It is preferable to do.

<Voltage conversion unit 9>
For example, a DC-DC converter with high conversion efficiency can be used for the voltage conversion unit 9 as the conversion device. As is well known, the DC-DC converter includes a switching element, a choke coil, a diode, an electrolytic capacitor, and the like. In general, a conversion device including a DC-DC converter has a smaller power loss due to conversion as the voltage difference before and after the conversion is smaller. In other words, the utilization efficiency of regenerative power can be increased as the voltage difference before and after conversion is smaller.

In this embodiment, since the output voltage of the alternator 12 is 14V and the fully charged voltage of the sub battery 2 is 13.3V, a DC step-down circuit (buck converter) whose input voltage is higher than the output voltage is used. . On the other hand, when the sub battery 2 is composed of an assembled battery in which eight unit cells are connected in series, the full charge voltage is 15.2 V (1.9 V / unit cell × 8 units). When the output voltage of the alternator 12 is 14V, a DC booster circuit (boost converter) whose input voltage is lower than the output voltage is used. Therefore, the voltage conversion unit 9 is determined by the number of single cells constituting the sub battery 2 and the output voltage of the alternator 12. The output side of the voltage conversion unit 9 is connected to the positive terminal of the sub battery 2.

< Controllers 3 and 4>
As shown in FIG. 1, the power supply system 10 includes a main battery controller 3 and a sub battery controller 4 that detect battery states of the main battery 1 and the sub battery 2, respectively (hereinafter, the controllers 3, 4 Is provided.) The controllers 3 and 4 detect battery states such as temperature, voltage, and current of the main battery 1 and the sub battery 2 during charging and discharging (during vehicle traveling and before vehicle traveling), respectively.

That is, in the present embodiment, the temperature sensor of the main battery 1 described above is connected to the main battery controller 3. The main battery controller 3 samples the voltage of the temperature sensor every predetermined time (for example, at intervals of 10 ms), and stores the sampling result in the RAM. Further, the positive terminal and the negative terminal of the main battery 1 are connected to the main battery controller 3 in order to detect the total voltage of the main battery 1.

Further, a current sensor 7 such as a Hall element or a shunt resistor is disposed between the main battery 1 and the charge / discharge switching unit 5 in order to detect a charge / discharge current flowing through the main battery 1. The current sensor 7 is connected to the main battery controller 3. The main battery controller 3 samples the voltage of the main battery 1 and the current flowing through the main battery 1 every predetermined time (for example, at intervals of 2 ms), and stores the sampling result in the RAM. The main battery controller 3 detects the open circuit voltage (hereinafter abbreviated as OCV) of the main battery 1 and the temperature at that time when charging / discharging is stopped (when the vehicle is parked).

On the other hand, the sub battery controller 4 also has the same configuration as the main battery controller 3 described above. The sub battery controller 4 detects the charge / discharge current flowing through the sub battery 2 with a current sensor 8 disposed between the voltage converter 9 and the charge / discharge switching unit 5 and the positive terminal of the sub battery 2. Further, in addition to the detection of the total voltage of the sub-battery 2, voltage detection other than that detected by the main battery controller 3 is also performed in that the voltage of each single cell is also detected in order to monitor overdischarge / overcharge. The sub battery controller 4 may have a capacity adjustment circuit that adjusts the capacity of each single battery constituting the sub battery 2.

The controllers 3 and 4 are connected to the control unit 6 (state grasping unit 6A), and at the time of charging / discharging, the temperature, voltage, current of the main battery 1 and the sub battery 2 stored in the RAM, and each of the sub batteries 2 are configured. The voltage of the unit cell is output to the control unit 6, and the detected OCV and the temperature at that time are output to the control unit 6 when charging / discharging is stopped.

<Control unit 6>
As shown in FIG. 1, the power supply system 10 includes a control unit 6 as a controller that calculates battery states of the main battery 1 and the sub battery 2 and controls a current switching operation by the charge / discharge switching unit 5. The control unit 6 is configured as a microprocessor having a microcontroller (hereinafter abbreviated as MC), a communication IC, an I / O, an input port, and an output port. In FIG. 1, details are shown by function in order to clarify the role of the control unit 6.

The MC serves as a work area for the CPU, a CPU for grasping (calculating) the battery status of the main battery 1 and the sub battery 2, a ROM for storing program data such as a basic control program and a table to be described later, and temporarily stores various data. RAM and an internal bus connecting them. The internal bus is connected to the external bus. The external bus is connected to the controllers 3 and 4 described above via an input port. In addition, an output port for outputting a signal to the charge / discharge switching unit 5 and a communication IC for communicating with the vehicle control unit 16 via the I / O and communication line 18 are connected to the external bus. .

Therefore, the MC and the input port of the control unit 6 correspond to the state grasping unit 6A in FIG. 1, the MC and the output port correspond to the switching control unit 6B, and the communication IC and I / O correspond to the communication unit 6C, respectively. Although the control part 6 also has other functions (for example, the function for shifting to the energy saving mode mentioned later), it is discarded in FIG. The charge / discharge switching unit 5 and the output port are connected by a control line. In order to prevent the MC constituting the control unit 6 from being damaged, a resistor is inserted in the control line. A high level signal (H) or a low level signal (L) is output to the control line via the output port.

The function of each part of the control unit 6 will be described with reference to FIG. The state grasping unit 6A temporarily stores the detection data output from the controllers 3 and 4 in the RAM, and calculates (estimates) the current battery state and the like of the main battery 1 and the sub battery 2. The communication unit 6C notifies the vehicle control unit 16 of the current battery state of the main battery 1 and the sub battery 2 calculated by the state grasping unit 6A every predetermined time (for example, 2 ms). Further, the communication unit 6C receives notification of vehicle state information (IGN position information, alternator operation information) from the vehicle control unit 16. The vehicle control unit 16 notifies the communication unit 6C of the operation information of the alternator 12 at substantially the same timing as when the electromagnetic clutch described above is operated. The switching control unit 6B controls the charging / discharging switching unit 5 according to the operation information of the alternator 12 notified from the vehicle control unit 16 and the battery status of the main battery 1 and the sub battery 2 calculated by the state grasping unit 6A.

In the present embodiment, the controllers 3 and 4, the charge / discharge switching unit 5, the control unit 6, the vehicle control unit 16, and the like are operated with electric power supplied from the main battery 1.

(Operation)
Next, the operation of the power supply system 10 according to the present embodiment will be described with the MC CPU (hereinafter abbreviated as CPU) of the control unit 6 as a main component.

<When charging / discharging is suspended (when the vehicle is parked)>
At the start of vehicle parking after the vehicle travels, the driver positions the IGN from the ON / ACC position to the OFF position, and the ignition key is withdrawn from the IGN. The vehicle control unit 16 monitors the IGN, and notifies the control unit 6 when the IGN is positioned at the OFF position.

The CPU that has received notification from the vehicle control unit 16 that the IGN has been positioned at the OFF position performs control to place the controllers 3 and 4 and the control unit 6 in the sleep state (energy saving mode). That is, the charge / discharge switching unit 5 is set to the above-described state “0”, and the controllers 3 and 4 are stopped from detecting and outputting the temperature, voltage, current, and the like of the main battery 1 and the sub battery 2.

Further, when the CPU itself stops the calculation of the battery state of the main battery 1 and the sub battery 2 and the notification to the vehicle control unit 16 and receives a notification from the vehicle control unit 16 that the IGN is positioned at the OFF position. Only the time counting process for determining whether or not a predetermined time has elapsed since the first time is performed. This predetermined time can be set to, for example, 6 hours when the polarization state of the negative electrode of the main battery 1 is considered to be eliminated.

When the CPU determines that a predetermined time has elapsed since the notification that the IGN is positioned at the OFF position from the vehicle control unit 16, the CPU awakes (shifts to the operating state) the controllers 3 and 4, and as described above. In addition, after the OCV of the main battery 1 and the sub battery 2 and the temperature at that time are detected and output, the controllers 3 and 4 are put into the sleeve state again.

Next, the CPU calculates the state of charge (hereinafter abbreviated as SOC) of the main battery 1 and the sub battery 2 from the OCV of the main battery 1 and the sub battery 2. Next, with reference to a table or mathematical expression stored in advance in the ROM as program data and expanded in the RAM, the calculated SOC is temperature-corrected to an SOC at a reference temperature (for example, 25 ° C.), and the main battery 1 and the sub battery 2 Is calculated (calculated).

In this case, the health state (hereinafter abbreviated as SOH) of the main battery 1 and the sub battery 2 may also be calculated and the SOC may be corrected according to the SOH. If the predetermined time does not elapse, the polarization state of the main battery 1 is not canceled and the reference SOC becomes inaccurate. Therefore, the OCV is detected by the controllers 3 and 4 in such a state, and the reference by the CPU. The SOC is not calculated, and the most recently acquired reference SOC is handled as the reference SOC.

Next, the CPU notifies the vehicle control unit 16 of the reference SOC and the voltage value, and then makes the control unit 6 sleep again. In other words, the control unit 6 is activated only when the controllers 3 and 4 detect and output the OCV and temperature, when calculating the reference SOC, and when notifying the vehicle control unit 16. When the IGN is positioned at the OFF position after the vehicle travels, the vehicle control unit 16 also performs a predetermined process (data storage, etc.) and then enters a sleep state, and is activated only when the control unit 6 notifies the OCV and temperature. It becomes.

<During charging and discharging (during vehicle travel and before vehicle travel)>
1. General control at the time of charge / discharge Before the vehicle travels after parking the vehicle, an ignition key is inserted into the IGN by the driver. The IGN is positioned from the OFF position to the ON / ACC position, is further positioned from the ON / ACC position to the START position, and is then positioned again at the ON / ACC position. When the IGN is first positioned at the ON / ACC position, the vehicle control unit 16 notifies the control unit 6 to that effect. Upon receiving the notification, the CPU shifts the controllers 3 and 4 and the control unit 6 to the operating state.

During charge / discharge (during vehicle travel and before vehicle travel), the CPU 3 and 4 detect voltage values of the main battery 1 and the sub battery 2 detected by the controllers 3 and 4 (for each cell constituting the sub battery 2). Voltage value is included). Further, based on the reference SOC and the battery capacities (known) of the main battery 1 and the sub battery 2, the current values detected at predetermined time intervals by the controllers 3 and 4 are integrated to determine the main battery 1 and the sub battery 2. The current SOC is estimated (calculated). Note that the voltage value and current value are temperature-corrected to the reference temperature described above. Then, the vehicle control unit 16 is notified of the current SOC and voltage values of the main battery 1 and the sub battery 2 at predetermined time intervals.

On the other hand, the vehicle control unit 16 that has received this notification refers to the current SOC and voltage values of the main battery 1 and the sub-battery 2 to operate the electromagnetic clutch described above and transmit the rotational force of the engine (not shown) to the alternator 12. It is determined whether or not (alternator 12 is operated to charge the electricity storage device).

That is, for example, when the main battery 1 is close to the use upper limit SOC (and / or the use upper limit voltage value), the vehicle control unit 16 may be in an electromagnetic clutch so that the alternator 12 is not operated. To control. Conversely, in the case of SOC (and / or lower limit voltage value) in which deterioration of the main battery 1 is promoted, the vehicle is traveling or traveling without waiting for regenerative charging by the driver's brake operation or accelerator operation. The electromagnetic clutch is controlled so as to charge the main battery 1 by operating the alternator 12 before. This specific control content will be described later.

2. Regenerative Charging / Discharging Control Here, the charging / discharging control of the present invention is briefly described. (I) When the power storage device accepts the regenerative power from the alternator 12, the sub battery 2 is used up to the upper limit SOC before the main battery 1 is reached. And / or after charging together with the main battery 1, after charging the main battery 1 alone, and (II) discharging the sub battery 2 to the first SOC described later when discharging from the power storage device to the discharge load 14, The main battery 1 is discharged.

The above (I) has various modes. Typical examples include the following three. The control unit 6
(A) Charging the main battery 1 after charging the sub battery 2 to the upper limit SOC,
(B) After charging the sub battery 2 to a second SOC, which will be described later, the sub battery 2 and the main battery 1 are both charged and the sub battery 2 is charged to the use upper limit SOC and then the main battery 1 is charged, or
(C) Charging the main battery 1 after charging both the sub battery 2 and the main battery 1 and charging the sub battery 2 to the upper limit SOC.
Thus, the charge / discharge switching unit 5 is controlled. Among these, the power supply system 10 of the present embodiment performs the charge / discharge control of the above (I), (a), and (II), and details are as follows.

2-1. Control at the time of regenerative charge When the CPU receives the regenerative start information indicating that the supply of regenerative power by the alternator 12 starts from the vehicle control unit 16, as a general rule, the CPU charges the sub battery 2 to the upper limit SOC. The charge / discharge switching unit 5 is controlled (the state “2” is selected by the charge / discharge switching unit 5). Thereby, the sub-battery 2 is charged at a constant voltage up to the use upper limit SOC with regenerative power.

However, when the regeneration end information indicating that the supply of regenerative power by the alternator 12 is terminated from the vehicle control unit 16 before the sub battery 2 reaches the use upper limit SOC, the regenerative power is not supplied. At that time, the charging of the sub-battery 2 is stopped, and the charge / discharge switching unit 5 is controlled so that the sub-battery 2 is immediately discharged from the sub-battery 2 to the discharge load 14 (the charge / discharge switching unit 5 selects state “4”).

Note that the vehicle control unit 16 controls the alternator 12 to output regenerative power when the brake is depressed or the accelerator is released (accelerator is off). Further, the controller 6 (CPU) is notified of the regeneration start information via the communication line 18. On the other hand, when the brake is released or when the acceleration of the vehicle becomes 0 as a result of the accelerator off, the operation of the alternator 12 is stopped. Further, the controller 6 (CPU) is notified of the regeneration end information via the communication line 18.

Further, when the sub battery 2 is charged up to the use upper limit SOC, in principle, the charge / discharge switching unit 5 is controlled to charge the main battery 1 to the use upper limit SOC (the state “1” is set in the charge / discharge switching unit 5). Let them choose.) As a result, the main battery 1 is charged at a constant voltage up to the upper limit SOC using regenerative power.

However, if the regeneration end information is received from the vehicle control unit 16 before the main battery 1 reaches the use upper limit SOC, the regenerative power is not supplied. The charge / discharge switching unit 5 is controlled to discharge from the battery 2 to the discharge load 14 (the state “4” is selected by the charge / discharge switching unit 5).

Further, when the main battery 1 is charged up to the upper limit SOC, in order to avoid overcharging of the main battery 1, the charging / discharging switching unit 5 is controlled so as to stop charging the main battery 1 (charging / discharging switching unit 5). To select the state “0”).

2-2. Control at the time of regenerative discharge When the CPU receives regenerative end information from the vehicle control unit 16, the sub-cell 2 is, in principle, a first SOC in which the sub-battery 2 is predetermined (FIG. 6A). The charge / discharge switching unit 5 is controlled so as to discharge until (see) (the state “4” is selected by the charge / discharge switching unit 5).

However, when the regeneration start information is received from the vehicle control unit 16 before the sub battery 2 becomes the first SOC, regenerative power is supplied, and at that time, the sub battery 2 is connected to the discharge load 14. The charge / discharge switching unit 5 is controlled so as to charge the sub battery 2 with regenerative power immediately after the discharge is stopped (the charge / discharge switching unit 5 selects the state “2”).

It is preferable to set the first SOC described above within a range in which the use efficiency of regenerative power can be increased and the deterioration of the sub battery 2 can be suppressed (for example, 10% to 80%). In the present embodiment, the first SOC is set to 10% less than the second SOC, which will be described later, and discharging is performed until any one of the single cells constituting the sub battery 2 becomes the first SOC. Therefore, in the present embodiment, the first SOC is the practical lower limit SOC of the sub battery 2. On the other hand, the upper limit SOC of the sub-battery 2 varies greatly depending on the capacity of the sub-battery 2 and the like, but generally any value in the range of 90% to 98% can be selected.

The first SOC can theoretically be set to 0% or more. The reason why the first SOC is set to 10% in the present embodiment is that even if there is a cumulative error in the SOC estimation (for example, when the above-mentioned reference SOC cannot be acquired during the latest vehicle parking), the sub SOC due to overdischarge This is to suppress the deterioration of the battery 2.

In addition, when any of the cells constituting sub battery 2 is discharged to the first SOC, in principle, main battery 1 is discharged to a predetermined third SOC (see FIG. 6B). The charge / discharge switching unit 5 is controlled as described above (the state “5” is selected by the charge / discharge switching unit 5).

However, if the regeneration start information is received from the vehicle control unit 16 before the main battery 1 becomes the third SOC, charging to the main battery 1 is stopped at that time, and the sub battery 2 is immediately regenerated with regenerative power. The charge / discharge switching unit 5 is controlled so as to be charged (the state “2” is selected by the charge / discharge switching unit 5).

The third SOC can be set to an SOC for preventing deterioration of the main battery 1 (Pb battery). In the Pb battery, it is generally considered that the deterioration is accelerated when the SOC is lower than 70%. Therefore, for the third SOC, for example, an arbitrary value in the range of SOC 70 to 90% can be selected. In the following description, it is assumed that the third SOC is set to 70%. In the present embodiment, the third SOC is the practical lower limit SOC of the main battery 1.

2-3. Relationship with ISS (charge control of main battery 1)
When charging the main battery 1 with regenerative power, it is preferable to charge the main battery 1 to the upper limit SOC (for example, 90% to 98%) in order to store the regenerative power as much as possible in the main battery 1. On the other hand, when the main battery 1 is discharged to the third SOC (70%), the alternator 12 needs to be operated when the main battery 1 is charged in order to prevent deterioration. The operation of the alternator 12 is accompanied by gasoline consumption because the power of an engine (not shown) is connected to the alternator 12. Therefore, charging may be performed from the third SOC to the upper limit SOC, but a predetermined fourth SOC (see FIG. 6B, (third SOC) <(fourth SOC) <( If the battery is charged up to the upper limit of use (SOC)), the main battery 1 may be further charged by regenerative power thereafter, so that fuel efficiency can be improved.

When the engine is restarted after idling is stopped, a large current is supplied from the main battery 1 to the starter. Even in this case, in order to prevent the deterioration of the main battery 1, it is necessary to maintain a value larger than the third SOC. For this reason, the above-described fourth SOC is, for example, (fourth SOC) = (third SOC) + {(SOC corresponding to the power supply to the discharge load 14 when idling is stopped + engine restart after idling is stopped) Min SOC)}.

When the main battery 1 is discharged to the third SOC, the CPU controls the main battery 1 to the fourth SOC by cooperative control with the vehicle control unit 16 as described above in order to prevent deterioration of the main battery 1. The charging / discharging switching unit 5 is controlled so as to be charged (the state “1” is selected for the charging / discharging switching unit 5).

Next, the above-described charge / discharge control will be further described with reference to a flowchart with the CPU as the main component. Note that the content (processing) that overlaps the content of the charge / discharge control already described will be described as briefly as possible.

As shown in FIG. 4, in the charge / discharge control routine, the process waits until the regeneration start information (step 102) or the regeneration end information (step 202) is received from the vehicle control unit 16.

When an affirmative determination is made at step 102 (when regeneration start information is received), the charge / discharge switching unit 5 is made to select the state “2” at step 104. Thereby, the sub battery 2 is charged at a constant voltage with regenerative power. Next, in step 112, it is determined whether or not regeneration end information has been received. If the determination is affirmative, the process proceeds to step 204 (charging to the sub-battery 2 is discontinued). If the determination is negative, it is determined in the next step 114 whether the sub-battery 2 has reached the upper limit SOC. If the determination in step 114 is negative, the process returns to step 112. If the determination is affirmative, the charge / discharge switching unit 5 is made to select the state “1” so that the main battery 1 is charged with regenerative power in the next step 116. Thereby, the main battery 1 is charged at a constant voltage with regenerative power.

Next, in step 118, it is determined whether or not regeneration completion information has been received. If the determination is affirmative, the process proceeds to step 204 (charging to the main battery 1 is discontinued). If the determination is negative, it is determined in the next step 120 whether the main battery 1 has reached the upper limit SOC. If the determination in step 120 is negative, the process returns to step 118. If the determination is affirmative, the charge / discharge switching unit 5 is selected to be in state “0” in the next step 122, and the process returns to step 102. As a result, the charging of the main battery 1 with regenerative power is discontinued.

On the other hand, when an affirmative determination is made in step 202 (when regeneration completion information is received), in step 204, the charge / discharge switching unit 5 is made to select the state “4”. Thereby, the electric power of the sub battery 2 is supplied to the discharge load 14. Next, in step 206, it is determined whether regeneration start information has been received. If the determination is affirmative, the process returns to step 104 (the discharge from the sub battery 2 to the discharge load 14 is terminated). If the determination is negative, it is determined in the next step 208 whether the sub battery 2 has reached the first SOC. To do. If the determination in step 208 is negative, the process returns to step 206. If the determination is affirmative, the charge / discharge switching unit 5 is made to select the state “5” in the next step 210. Thereby, the power of the main battery 1 is supplied to the discharge load 14.

Next, in step 212, it is determined whether or not regeneration end information has been received. If the determination is affirmative, the process returns to step 104 (the discharge from the main battery 1 to the discharge load 14 is terminated). If the determination is negative, it is determined in the next step 214 whether the main battery 1 has reached the third SOC. To do. If the determination in step 214 is negative, the process returns to step 212. If the determination is affirmative, main battery charging processing for charging the main battery 1 is executed in the next step 216. The charge / discharge control routine is terminated when the control unit 6 enters a sleep state upon receiving a notification from the vehicle control unit 16 that the IGN is positioned at the OFF position. Returned to "0".

As shown in FIG. 5, in the main battery charging processing subroutine, in step 232, the vehicle control unit 16 is notified that the main battery 1 has reached the third SOC. Receiving this notification, the vehicle control unit 16 starts the alternator 12 by operating the electromagnetic clutch described above and transmitting the rotational force of the engine (not shown) to the alternator 12. Then, alternator start information indicating that the alternator 12 is started is notified to the control unit 6 (CPU). On the other hand, the CPU waits until the alternator start information is received from the vehicle control unit 16 (step 234). During this time, since the main battery 1 is still discharged to the discharge load 14, the SOC of the main battery 1 is smaller than the above-described third SOC. In order to prevent the SOC of the main battery 1 from becoming smaller than the third SOC, the vehicle controller 16 informs the vehicle control unit 16 that the main battery 1 reaches the third SOC before the main battery 1 reaches the third SOC. What is necessary is just to alert | report.

If the CPU makes an affirmative determination in step 234 (receives alternator start information from the vehicle control unit 16), it causes the charge / discharge switching unit 5 to select the state "1" in the next step 236. As a result, the main battery 1 is charged at a constant voltage, but as described above, this charging is not based on regenerative electric power, and is a charging method similar to that of a conventional gasoline vehicle or the like.

In the next step 238, the process waits until the main battery 1 is charged to the fourth SOC. When the main battery 1 is charged up to the fourth SOC, in the next step 240, the vehicle control unit 16 is notified that the main battery 1 has been charged up to the fourth SOC, and the main battery charging process subroutine is terminated. Return to step 102 in FIG. Thereby, the vehicle control part 16 stops the transmission to the alternator 12 of the rotational force of the engine which is not shown in figure by the electromagnetic clutch mentioned above.

In addition, in the above, in order to explain the contents of control in an easy-to-understand manner, an example in which the main battery 1 has reached the third and fourth SOCs in steps 232 and 240 has been shown (see FIG. 5). However, as described above, the control unit 6 notifies the vehicle control unit 16 of the SOCs of the main battery 1 and the sub battery 2 every predetermined time, and thus it is not always necessary to perform such notification. For example, the vehicle control unit 16 monitors the SOC of the main battery 1 notified every predetermined time, and controls the control unit so that the alternator 12 starts when the main battery 1 reaches the third SOC or immediately before that. Alternatively, the alternator start information may be notified to 6.

Further, for the charging of the main battery 1, the same processing as in steps 214 and 216 in FIG. 4 is performed before the vehicle travels. However, while the vehicle travels, it is determined in step 214 whether the main battery 1 has reached the third SOC, whereas before the vehicle travels, since the CPU has just awakened, the main battery 1 is subject to the third due to self-discharge or the like. The difference is that it is determined whether or not the SOC is equal to or lower than the SOC.

Furthermore, in the above description, the SOC has been mainly described in order to briefly explain the charge / discharge control. In the present embodiment, in addition to the use upper limit SOC of the sub battery 2, the use upper limit voltage V _U , the use lower limit voltage V _{L of} the sub battery 2, the use upper limit voltage of each cell constituting the sub battery 2, and the use lower limit voltage Is also preset. When the sub-battery 2 has reached the upper limit operating voltage V _U charges the discontinuation main battery 1 to charge the sub battery 2 due to regenerative power. On the other hand, when the sub battery 2 reaches the use lower limit voltage V _L , the use lower limit voltage of each single battery, and a voltage that is predetermined in correspondence with the first SOC, the sub battery 2 transfers to the discharge load 14. Control is also performed so that the main battery 1 is discharged and discharged to the discharge load 14. Similarly to the sub battery 2, the main battery 1 has a use upper limit voltage and a use lower limit voltage set. Similar to the sub battery 2, the main battery 1 further has a third SOC according to the use upper limit voltage and the use lower limit voltage. The charging / discharging control of the main battery 1 is also performed according to a voltage determined in advance.

3. Abnormal Processing The CPU also monitors whether the voltage and temperature of the main battery 1 are within a predetermined range, whether the voltage of each single cell constituting the sub battery 2 is within a predetermined range, and the temperature of the sub battery 2. When the voltage or temperature is out of a predetermined range set in advance, this is also notified to the vehicle control unit 16. Such an abnormality is preferably processed in different stages, and the vehicle control unit 16 displays the fact on the installation panel as necessary. The CPU may cause the charge / discharge switching unit 5 to select a state so that only one of the main battery 1 and the sub battery 2 is used instead of the other depending on the abnormal state.

[Second Embodiment]
Next, a second embodiment in which the present invention is applied to a power supply system that can be mounted on an alternator regenerative vehicle will be described. In this embodiment, when the electricity storage device (I) receives regenerative power from the alternator 12, (b) the sub battery 2 and the main battery 1 are charged together after the sub battery 2 is charged to the second SOC. The charge / discharge switching unit 5 is controlled to charge the main battery 1 after charging the battery 2 to the upper limit SOC. In the following embodiments, the same configurations and operations as those of the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

In the second embodiment, as shown in Table 2 below, the charge / discharge switching unit 5 adds the first switch SW1 and the states “0” to “2”, “4”, “5” shown in Table 1 By setting the second switch SW2 to the on state and the third switch SW3 to the off state, the alternator 12 is in the state “3” connected in parallel to the sub battery 2 via the main battery 1 and the voltage converter 9. However, when the main battery 1 has a battery voltage higher than that of the sub battery 2 and is connected in parallel when discharging to the discharge load 14, the sub battery 2 may be charged by the main battery 1. 2 is not connected to the discharge load 14 together. This also applies to a third embodiment described later.

Next, charge / discharge control of the power supply system 10 of the second embodiment will be described with reference to FIG. FIG. 7 differs in that steps 106 to 110 are inserted between step 104 and step 112 in FIG. 4, and only this difference will be described below.

In step 106 following step 104, it is determined whether or not regeneration end information has been received. If the determination is affirmative, the process proceeds to step 204 (charging to the sub-battery 2 is discontinued). If the determination is negative, it is determined in the next step 108 whether the sub-battery 2 has reached the second SOC.

For the second SOC, for example, an arbitrary value in the range of 70% to 90% can be selected (see also FIG. 6A). In the present embodiment, the second SOC is set to 80%. Therefore, in this embodiment, in order to increase the utilization efficiency of the regenerative power by the sub battery 2, the difference between the second SOC (80%) and the first SOC (10%) is set to 70%. This difference is preferably as large as possible for the power supply system, and is desirably at least 60% or more. That is, there is a tradeoff between the certainty of preventing the deterioration of the sub battery 2 (both on the overcharge side and the over discharge side) and improving the utilization efficiency of the regenerative power by the sub battery 2.

If the determination in step 108 is negative, the process returns to step 106. If the determination is affirmative, the charge / discharge switching unit 5 is selected in state “3” in the next step 110, and the process proceeds to step 112. Thereby, the sub battery 2 and the main battery 1 are connected in parallel (parallel charging), and both are charged at a constant voltage by regenerative power.

[Third Embodiment]
Next, a third embodiment in which the present invention is applied to a power supply system that can be mounted on an alternator regenerative vehicle will be described. In the present embodiment, when the electricity storage device of (I) receives regenerative power from the alternator 12, (c) the sub battery 2 and the main battery 1 are both charged and the sub battery 2 is charged to the upper limit SOC and then the main battery The charge / discharge switching unit 5 is controlled to charge 1.

In the third embodiment, as shown in Table 3 below, the charge / discharge switching unit 5 turns on the first switch SW1 and the second switch SW2 instead of the state “2” shown in Table 1, When the switch SW3 is turned off, the alternator 12 is connected in parallel to the sub battery 2 via the main battery 1 and the voltage converter 9.

The charge / discharge control of the power supply system 10 of the third embodiment will be described with reference to FIG. FIG. 8 differs in that step 105 is executed instead of step 104 in FIG. That is, when the determination in step 102 is affirmative, the charge / discharge switching unit 5 is selected in the state “3” in step 105, and the process proceeds to step 112. Thereby, the sub battery 2 and the main battery 1 are connected in parallel (parallel charging), and both are charged at a constant voltage by regenerative power.

(Effects etc.)
Next, functions and effects of the power supply system 10 according to the first to third embodiments will be described.

In the power supply system 10 of the above embodiment, the Pb battery main battery 1 and the NiZn battery sub-battery 2 constitute a composite power storage device. Therefore, the Pb battery and the lithium ion battery composite power storage device or Pb battery mentioned as the prior art As compared with the case of using a NiMH battery composite power storage device, it is possible to provide a power supply system that is low in cost and excellent in energy density and safety.

In the power supply system 10 of the above embodiment, when the regenerative power of (I) is received, the charge / discharge switching is performed so that the sub battery 2 or the main battery 1 is charged by any of the above (a) to (c). When controlling the unit 5 to discharge to the discharge load 14 of the above (II), the charge / discharge switching unit 5 is controlled so that the sub battery 2 is discharged to the first SOC and then discharged from the main battery 1. . For this reason, since the regenerative electric power stored in the sub-battery 2 can be immediately discharged to the discharge load 14 without waiting for the charging / discharging pause as in the power supply system of Patent Document 1, for example, the use efficiency of the entire power storage device is increased. The fuel consumption improvement rate can be improved.

Moreover, in the power supply system 10 of the said embodiment, when the control part 6 discharged from the electrical storage device to the discharge load 14, it discharged until one of each single battery which comprises the subcell 2 became 1st SOC. Later, the charge / discharge switching unit 5 is controlled to discharge from the main battery 1. In order to suppress the discharge of the sub battery 2 with the first SOC, the deterioration of the sub battery 2 can be prevented, and the power stored in the sub battery 2 within the range from the upper limit SOC to the first SOC is discharged to the discharge load 14. Therefore, high utilization efficiency can be ensured for the regenerative power generated by the alternator 12.

Further, in the power supply system 10 of the second and third embodiments, the sub battery 2 and the main battery 1 are charged in parallel with regenerative power, so that the main battery 1 is substantially third SOC while improving the utilization efficiency of the sub battery 2. The above SOC can be maintained. For this reason, it is possible to prevent a decrease in fuel efficiency due to gasoline consumption. In the second embodiment, since the sub battery 2 and the main battery 1 are charged in parallel after the sub battery 2 is charged to the second SOC (80%) first, the utilization efficiency of the sub battery 2 is higher than that of the third embodiment. Can be increased.

Furthermore, in the power supply system 10 of the above embodiment, the main battery 1 is an electric storage device for starting the engine, and the control unit 6 also estimates the SOC of the main battery 1. Since the CPU controls the charge / discharge switching unit 5 to charge the main battery 1 when the main battery 1 is discharged to the third SOC (70%), the deterioration of the main battery 1 can also be prevented. . At this time, since the CPU controls the charge / discharge switching unit 5 so as to charge the main battery 1 to the fourth SOC less than the upper limit SOC, the fuel consumption can be improved as described above.

In the above embodiment, an example in which the present invention is applied to a vehicle power supply system is shown. However, the present invention is not limited to the illustrated vehicle power supply system. That is, the present invention can be applied to a moving body other than a vehicle, and can also be applied to a stationary power supply system.

Moreover, in the said embodiment, although the electrical storage device which has one main battery 1 and one sub battery 2 comprised by the cell 7 series or 8 series was illustrated, this invention is restrict | limited to this. It is not a thing. For example, a plurality of Pb batteries and one or a plurality of NiZn batteries may be combined (for example, connected in series and parallel) to form a high voltage / large capacity power storage device. At that time, several Pb batteries and several NiZn batteries are respectively or simultaneously contained in one casing to constitute one battery group unit, and a plurality of battery group units constitute an electricity storage device. May be. With such a configuration, for example, it can be applied as a home / business power supply system in an electric vehicle, a ship, wind power / solar power generation. At this time, the power supply system may further include a DC-AC converter in order to supply power from the power storage device to the discharge load.

Furthermore, in the said embodiment, the example which estimated current SOC of the main battery 1 and the sub battery 2 by calculating reference | standard SOC from OCV, and integrating | accumulating charging / discharging electric current with respect to this reference | standard SOC was shown. However, the present invention is not limited to this, and a known SOC estimation means can be used.

In the above embodiment, an example in which three switching elements are used for the charge / discharge switching unit 5 as a switching device is shown, and a DC-DC converter is illustrated as the voltage conversion unit 9 as a conversion device. However, the present invention is not limited to this, and various devices having functions similar to those of the charge / discharge switching unit 5 and the voltage conversion unit 9 may be used as appropriate.

In the above embodiment, the main battery controller 3, the sub battery controller 4, and the control unit 6 are described separately so that the configuration of the power supply system 10 can be easily grasped. However, these may be configured integrally. Furthermore, in the said embodiment, although the control part 6 calculated the battery state of the main battery 1 and the sub battery 2 according to the detection data of the main battery 1 and the sub battery 2 output from the controllers 3 and 4 was shown. Such calculation may be performed by the vehicle control unit 16. In such an aspect, the main functions of the control unit 6 are the switching control unit 6B and the communication unit 6C.

Furthermore, in the said embodiment, the example which performs engine starting with the main battery 1 was shown. However, the present invention is not limited to this, and the engine may be started by the sub battery 2. Moreover, in the said embodiment, the example in which the operating electric power of the controllers 3 and 4, the control part 6, and the vehicle control part 16 was supplied from the main battery 1 was shown. However, it may be supplied from the sub-battery 2, and the main battery 1 and the sub-battery 2 cooperate or share the operating power to the controllers 3, 4, the control unit 6, and the vehicle control unit 16. You may make it do. Therefore, in the present invention, the battery capacity of the main battery 1 may be larger, smaller, or the same as the battery capacity of the sub battery 2.

Moreover, in the said embodiment, although the example which performs OCV measurement of the main battery 1 and the sub battery 2 after 6 hours of vehicle parking according to the Pb battery which comprises the main battery 1 was shown, this invention is restrict | limited to this. It is not something. In the above embodiment, the CPU of the control unit 6 counts six hours. However, the vehicle control unit 16 counts the time and causes the control unit 6 and the controllers 3 and 4 to wake from the sleep state. Good.

Furthermore, in the said embodiment, although the control part 6 showed the example which acquires the operation information of an alternator via the vehicle control part 16, this invention is not limited to this. For example, brake operation information and alternator operation information may be obtained directly from a brake control unit that controls the brake and an alternator control unit that controls the alternator.

And in this embodiment, the 14V type | system | group power supply system 10 was illustrated. However, the present invention is not limited to this, and can be applied to a power supply system other than a 14V power supply system such as a 42V power supply system.

The present invention provides a power supply system that is low in cost, excellent in energy density and safety, and highly efficient in use with respect to supplied power, and a vehicle equipped with the power supply system. For this reason, since this invention contributes to manufacture and sale of a power supply system or a motor vehicle, it has industrial applicability.

Claims (15)

1. An electricity storage device having a lead storage battery (Pb battery) and a nickel zinc storage battery (NiZn battery), capable of receiving supplied power and discharging to a discharge load;
   A switching device for switching charge / discharge currents of the Pb battery and the NiZn battery;
   A controller that estimates a state of charge (SOC) of the NiZn battery and controls the switching device based on the estimated SOC;
   With
   The controller is
   When the power storage device accepts the supplied power, the NiZn battery is charged to the upper limit SOC before the Pb battery and / or together with the Pb battery, and then the Pb battery is charged,
   When the electricity storage device is discharged to the discharge load, after discharging the NiZn battery to a predetermined first SOC, discharging from the Pb battery,
   A power supply system that controls the switching device as described above.
2. The power supply system according to claim 1, wherein the supplied power is regenerative power supplied from an alternator, and the power supply system is a vehicle power supply system.
3. The controller, when the storage device accepts the regenerative power,
   (A) charging the Pb battery after charging the NiZn battery to the upper limit SOC;
   (B) charging the NiZn battery to a predetermined second SOC and then charging both the NiZn battery and the Pb battery and charging the NiZn battery to the upper limit SOC, or charging the Pb battery, or ,
   (C) Charging the NiZn battery and the Pb battery together, charging the NiZn battery to the upper limit SOC, and then charging the Pb battery.
   The power supply system according to claim 2, wherein the switching device is controlled as described above.
4. The power supply system according to claim 3, wherein a difference between the second SOC and the first SOC is set to 60% or more.
5. 5. The power supply system according to claim 4, wherein the first SOC is set to be less than the second SOC and 10% or more, and the second SOC is set to a range of 70% to 90%. .
6. The controller is
   Regenerative start information indicating that supply of regenerative power by the alternator starts from the vehicle side and regeneration end information indicating that supply of regenerative power by the alternator ends,
   When acquiring the regeneration start information, start charging the NiZn battery or the Pb battery with the regenerative power,
   When the regeneration end information is acquired, the charging of the NiZn battery or the Pb battery with the regenerative power is stopped and discharged from the NiZn battery to the discharge load.
   The power supply system according to claim 2, wherein the switching device is controlled as described above.
7. The power supply system according to claim 2, further comprising a conversion device that is inserted between the switching device and the NiZn battery and converts the voltage of the regenerative power.
8. The switching device includes a first switch for turning on / off the connection between the alternator and the discharge load and the Pb battery, and a second switch for turning on / off the connection between the alternator and the conversion device. The power supply system according to claim 6, further comprising: a switch; and a third switch for turning on / off the connection between the discharge load and the NiZn battery.
9. The NiZn battery is configured by connecting a plurality of single cells in series,
   When the electric storage device is discharged to the discharge load, the controller discharges from the Pb battery after discharging any of the plurality of single cells constituting the NiZn battery to the first SOC. To control the switching device,
   The power supply system according to claim 7.
10. The power supply system according to claim 9, wherein the first SOC is set to be less than the upper limit SOC and 10% or more.
11. The Pb battery is a storage battery for starting an engine,
    The controller further estimates the SOC of the Pb battery, and controls the switching device to charge the Pb battery when the Pb battery is discharged to a predetermined third SOC.
    The power supply system according to claim 7.
12. The power supply system according to claim 11, wherein the third SOC is set to be less than the upper limit SOC and 70% or more.
13. The power supply system according to claim 7, wherein the conversion device includes a DC step-down circuit or a DC step-up circuit.
14. 8. The power supply system according to claim 7, wherein the NiZn battery is an assembled battery in which single cells are connected in 7 series or 8 series.
15. An automobile equipped with the power supply system according to claim 1.

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