JP6750316B2 - Vehicle power supply system and automobile - Google Patents

Description

The present invention relates to a vehicle power supply system and a vehicle, and more particularly, to a vehicle power supply system including an electric storage device that can receive regenerative power supplied from an alternator and discharge into a discharge load, and a vehicle including the power supply system.

BACKGROUND ART Conventionally, in a moving body (vehicle) such as an automobile, the electric power supplied from the alternator is charged to a power storage device such as a lead storage battery during driving except when braking, so that the power storage device is almost fully charged. It was kept charged. In recent years, from the viewpoint of suppressing carbon dioxide emission, in such gasoline vehicles, vehicles having an idling stop system function (ISS vehicles) are gradually increasing.

In ISS vehicles, the engine is stopped when the vehicle is stopped (therefore, charging of the electricity storage device from the alternator is also stopped), and during that time, the electricity storage device supplies all power to auxiliary equipment such as lamps and electrical equipment. At the start after the 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 to improve fuel efficiency has been particularly high, helped by the rise in the retail price of gasoline, and the number of vehicles with high fuel efficiency has increased significantly. Based on such a situation, automobile (manufacturing) companies are developing an alternator regenerative vehicle that charges an electricity storage device with regenerative power supplied from the alternator during braking. Such an alternator regenerative vehicle includes a vehicle having the above-mentioned ISS function, and such a vehicle may be called a μHEV or a micro hybrid.

In an alternator regenerative vehicle, the electricity storage device is charged with regenerative power supplied from the alternator at the time of braking, which was consumed by ordinary gasoline vehicles, and the operation of the alternator is stopped in principle during driving except during braking (electricity storage). Reduce gasoline consumption by the engine to operate the alternator (by stopping charging the device). The electricity storage device supplies power to all the auxiliary devices while the alternator is stopped. When the state of charge (SOC) of the electricity storage device becomes less than or equal to a preset value, the alternator is activated during or before traveling to charge the electricity storage device in order to prevent overdischarging of the electricity storage device. To do.

In such a power supply system mounted on an alternator regenerative vehicle, various researches and developments such as a power storage device itself and a control technique have been conducted in order to receive regenerative electric power supplied from the alternator during braking. For example, Patent Document 1 discloses a power supply system including an electricity storage device including a water-based lead storage battery (main battery) and a non-aqueous lithium-ion battery (sub battery) having high charge acceptance. Further, in Patent Document 2, a power storage device having a lead storage battery (main battery) and a capacitor having high charge acceptance (electric double layer capacitor, electrolytic capacitor, lithium ion capacitor) and a generator (alternator) are supplied. A power supply system including a DC-DC converter for converting the voltage of regenerative power is disclosed.

Japanese Unexamined Patent Application Publication No. 2011-176958 (see FIG. 1, claim 1, paragraph “0071”) JP-A-2005-009790 (see FIG. 1, claim 1, paragraphs “0013” to “0019”)

By the way, the technique of Patent Document 1 has a problem that the life of the lead storage battery is shortened because the engine is mainly started by the lead storage battery (see paragraphs “0078” and “0081”). That is, since a large current is discharged from the lead acid battery to the starter when the engine is started, the deterioration is promoted (significantly compared with the case of a relatively small current discharged to the auxiliary machine). Further, the technique of Patent Document 2 has a problem that energy loss occurs during voltage conversion of regenerative power by the DC-DC converter.

In view of the above-mentioned case, it is an object of the present invention to provide a vehicle power supply system capable of suppressing the shortening of the life of the secondary battery while improving the utilization efficiency of regenerative power, and a vehicle equipped with the power supply system.

In order to solve the above problems, a first aspect of the present invention is a vehicle power supply system, which has a secondary battery and a lithium ion capacitor (LIC) and can receive regenerative power supplied from an alternator. And a composite electric storage device capable of discharging to a starter for starting an engine and an auxiliary device, a switch means for switching a charge/discharge current of the secondary battery and the LIC, and a control means for controlling the switch means based on the voltage of the LIC. And, when the power storage device receives the regenerative power, the control means charges the LIC to a preset use upper limit voltage V1 and then charges the secondary battery, and the power storage device is When discharging to the auxiliary machinery, after discharging from the LIC until the voltage reaches a preset voltage V2, the secondary battery discharges, and when the engine starts, the LIC discharges to the starter. And controlling the switch means.

In the first aspect, when the regenerative power is received by the control means, the LIC having a high charge acceptability is charged up to the use upper limit voltage V1 prior to the secondary battery, and the secondary battery is charged when the auxiliary device is discharged. The switch means is controlled so that the LIC is discharged to the set voltage V2 in advance. For this reason, the utilization efficiency of the regenerative power supplied from the alternator can be improved, and since the LIC is charged and discharged prior to the secondary battery, the number of opportunities for charging and discharging the secondary battery is reduced. It is possible to prevent deterioration. This set voltage V2 can be set to a voltage value equal to or higher than the lowest voltage at which the engine can be started by discharging the LIC to the starter. In that case, even if the LIC is discharged to the auxiliary device prior to the secondary battery, the LIC can maintain a voltage at which the engine can be started. Then, the control means controls the switch means so that the LIC, which is excellent in the large current discharge characteristic, is discharged to the starter when the engine is started. Therefore, the deterioration of the secondary battery due to the engine start can be prevented. Therefore, it is possible to improve the utilization efficiency of the regenerative power by receiving the regenerative power from the LIC, which has excellent charge acceptance before the secondary battery, and discharging the rechargeable power from the LIC to the starter and auxiliary equipment before the secondary battery. Since the discharge load (starter and auxiliary machine) of the secondary battery including the large current discharge to the starter at the time of starting is reduced, the deterioration of the secondary battery can be prevented and the life shortening can be suppressed.

In the first aspect, the control means may control the switch means so that the LIC discharges the starter and the auxiliary machine when the engine is started at the time of idling stop start. Further, it further comprises an acquisition means for acquiring vehicle state information, which means that the acquisition means acquires idling stop start information indicating that the vehicle will start and stop idling, and then indicates that the engine has started by idling stop start. The switch means may be controlled so as to maintain the switch state in which the LIC discharges the starter and the auxiliary machine until the engine start information is acquired. Further, the control means may control the switch means so that the secondary battery is discharged to the auxiliary machine when the acquisition means acquires the engine start information.

Further, the control means may control the switch means so as to connect the secondary battery and the LIC in parallel when charging/discharging is suspended. At this time, in order to prevent over-discharging of the LIC, the control means controls the voltage of the LIC to be less than a preset voltage V3 (provided that the lower limit voltage V4 of the LIC is less than the use voltage V4<the preset voltage V3<the preset voltage V2) and the secondary voltage. The switch means may be controlled so that the secondary battery and the LIC are connected in parallel when the battery voltage is equal to or higher than the set voltage V3. Further, in order to start the engine with the power of the LIC, the control means connects the secondary battery and the LIC in parallel when the voltage of the LIC is less than the set voltage V2 and the voltage of the secondary battery is the set voltage V2 or more. You may make it control a switch means like this.

Then, as the secondary battery, one kind selected from the group consisting of a lead storage battery, a nickel hydrogen battery, a nickel zinc battery and a lithium ion battery can be used.

In order to solve the above-mentioned subject, the 2nd mode of the present invention is an automobile provided with the power supply system for vehicles of the 1st mode.

According to the present invention, when the regenerative power is received by the control means, the LIC having a high charge acceptability is charged up to the use upper limit voltage V1 prior to the secondary battery, and the secondary battery is charged when the auxiliary device is discharged. Since the switch means is controlled so as to discharge the LIC to the set voltage V2 in advance, the utilization efficiency of the regenerative power supplied from the alternator can be improved, and the opportunity for charging/discharging the secondary battery can be reduced to start the engine. At this time, since the switch means is controlled so as to discharge from the LIC to the starter, it is possible to obtain an effect that the deterioration of the secondary battery can be prevented and the shortening of the life can be suppressed.

It is a block circuit diagram of a power supply system of an embodiment to which the present invention is applicable. 5 is a flowchart of a charge/discharge control routine executed by the CPU of the microcontroller (MC) of the control unit of the power supply system of the embodiment. 6 is a flowchart of a pre-engine start charge/discharge processing subroutine showing details of step 108 of the charge/discharge control routine. 5 is a flowchart of an engine start processing subroutine showing details of step 114 of the charge/discharge control routine. 6 is a flowchart of a regenerative charge/discharge processing subroutine showing details of step 110 of the charge/discharge control routine. 9 is a flowchart of a charge/discharge pause processing subroutine showing details of step 116 of the charge/discharge control routine. 6 is a flowchart of a charge processing subroutine showing details of step 164 of the charge/discharge processing subroutine before engine start and step 246 of the regenerative charge/discharge processing subroutine. It is explanatory drawing which shows the device state of a composite energy storage device typically, (A) shows the voltage of a lithium ion capacitor (LIC), (B) shows the charge state of a main battery.

An embodiment in which the present invention is applied to a 14V vehicle power supply system that can be mounted on an alternator regenerative vehicle will be described below with reference to the drawings.

1. Configuration 1-1. Configuration on Vehicle Side First, before referring to the power supply system 10 of the present embodiment, a main configuration of an alternator regenerative vehicle (μHEV) 20 on which the power supply system 10 is mounted will be briefly described. Note that μHEV refers to a gasoline vehicle or a diesel vehicle that has an ISS function, is capable of receiving regenerative power supplied from an alternator, and is provided with a power storage device capable of discharging a discharge load (starter and auxiliary equipment).

(1) Ignition switch (IGN) 11
As shown in FIG. 1, the alternator regenerative vehicle 20 is provided with an ignition switch 11 (hereinafter, abbreviated as IGN 11) similarly to a normal gasoline vehicle. The IGN 11 is positioned by the driver at one of the OFF position, the ON/ACC position, and the START position. That is, the vehicle is positioned in the OFF position when the vehicle is parked, in the ON/ACC position before and after the vehicle travels, and in the START position when the engine is started. Note that “ACC” means an accessory, that is, an auxiliary machine (a position for supplying electric power from the composite power storage device 1 to the auxiliary machine). The IGN 11 notifies the vehicle control unit 15 every time its position is changed.

(2) Vehicle control unit 15
Further, the alternator regenerative vehicle 20 includes a vehicle control unit (ECU) 15 that controls the operation of the alternator regenerative vehicle 20 as a whole. The vehicle control unit 15 grasps the position information of the IGN 11, grasps the operating states of the accelerator, the brake, the engine, etc., the speed, the acceleration, and other vehicle states, and performs traveling control according to the grasped states.

In addition, the vehicle control unit 15 communicates with the control unit 7 of the power supply system 10 via the communication line 16 and is in the device state of the composite power storage device 1 (hereinafter, abbreviated as the power storage device 1) that constitutes the power supply system 10. In addition to receiving the notification, the control unit 7 is notified of the vehicle state information. The vehicle state information includes IGN position information, alternator operation information, and idling information (details will be described later), as shown in Table 1 below.

(3) 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 during braking or accelerator off. The (rotational) driving force of the engine is transmitted to the alternator 12 via an electromagnetic clutch (not shown). In this embodiment, the output voltage of the alternator 12 is set to 14.0 [V]. As will be described later, depending on the device state of the electricity storage device 1, power may be generated by the alternator 12 other than during regenerative power generation.

The alternator 12 includes a power generation unit including a stator and a rotor, a rectification unit that converts the AC power generated by the power generation unit into DC power, and a voltage that keeps the voltage of the DC power converted by the rectification unit constant. And a regulator. It should be noted that one end of the alternator 12 is connected to the ground (the same potential as the chassis of the vehicle; hereinafter abbreviated as GND), and the other end is connected to one end of a starter 13 and an auxiliary machine 14 described later and a switch 6 described later. Connected to a point.

(4) Starter 13
Further, the alternator regenerative vehicle 20 includes a starter 13 that starts the engine. The starter 13 is, as is well known, a DC series-wound motor (cell motor) having a field (excitation) coil and an armature (rotation) coil, a main contact for supplying electric power of the power storage device 1 to the motor, and a plunger. And a holding (holding) coil, which is arranged around the base and which advances and retracts and holds the plunger, and a conductor member fixed to the plunger. The other end of the starter 13 is connected to GND.

When the engine of the alternator regenerative vehicle 20 is started, electric power is supplied from the power storage device 1 to the pull-in coil and the holding coil, and the plunger is moved (pulled in and held) to be connected to the DC series-wound motor. And the other main contact connected to the electricity storage device 1 are electrically connected to each other by the above-described conductor member, whereby the motor rotates, and the rotational force of this motor causes the crankshaft to rotate. Therefore, when IGN 11 is positioned at the START position, electric power is supplied from power storage device 1 to starter 13 to rotate starter 13, and the rotational force of starter 13 is transmitted to the engine via the crankshaft to start the engine.

(5) Auxiliary machine 14
Further, various alternators (accessories) 14 are mounted on the alternator regenerative vehicle 20. Examples of the auxiliary device 14 include a lamp, a light, a power window, an engine pump (spark plug), an air conditioner, a fan, a radio, a television, a CD player, and a car navigation. The other end of the auxiliary machine 14 is connected to GND. The auxiliary device 14 may be supplied with an operating voltage equal to or higher than the minimum operating voltage (for example, 8 [V]) from the power storage device 1.

1-2. Configuration of Power Supply System Next, the configuration of the power supply system 10 of the present embodiment will be described. The power supply system 10 is mounted in, for example, the engine room of the alternator regenerative vehicle 20, but the present invention is not limited to this.

(1) Composite power storage device 1
As shown in FIG. 1, the power supply system 10 of the present embodiment can receive regenerative power supplied from the alternator 12 and discharges the starter 13 and the auxiliary machine 14 (hereinafter, both are collectively referred to as a discharge load). It comprises a possible electricity storage device 1. The electricity storage device 1 is configured as a composite electricity storage device including a main battery 2 (lead storage battery in this example) and a lithium ion capacitor 3 (hereinafter abbreviated as LIC3).

(1-1) Main battery 2
As the battery case of the main battery 2, a monoblock battery case that defines six cell chambers by partition walls that partition the inside is used. A sensor insertion hole is formed in the central partition of the monoblock battery case from the upper side to approximately the central part. A temperature sensor such as a thermistor for detecting the temperature of the central portion of the main battery 2 is inserted in the sensor insertion hole, and the temperature sensor is fixed in the sensor insertion hole with an adhesive.

Each cell chamber of the main battery 2 accommodates one set of electrode plates in which a plurality of positive electrode plates and negative electrode plates are stacked with a separator interposed therebetween, and dilute sulfuric acid that is an aqueous electrolytic solution is injected. .. Lead dioxide can be used for the positive electrode active material of the main battery 2, and spongy lead can be used for the negative electrode active material. In addition, in order to make it easy to receive regenerative power, the negative electrode active material mixture is mixed with a negative electrode additive containing lignin, carbon and the like in addition to the above-mentioned negative electrode active material.

Each cell chamber is sealed with a lid that integrally covers the opening of the monoblock battery case, and the cell chambers are connected in series by a conductive connecting member. A positive electrode terminal and a negative electrode terminal, which are external output terminals, are erected at diagonally upper positions of the main battery 2. The nominal voltage of the main battery 2 of this embodiment is 12 [V] (nominal voltage of each cell: 2 [V]). The capacity of the main battery 2 can be, for example, 30 to 70 Ah (32 Ah in this example), but the present invention is not limited to this. The negative terminal of the main battery 2 is connected to GND.

(1-2) LIC3
On the other hand, the LIC 3 of this embodiment has a single (unit) lithium-ion capacitor (hereinafter, abbreviated as a single capacitor. A group of capacitors (group capacitors) connected in series, each having a positive electrode terminal on the highest potential side and a negative electrode terminal on the lowest potential side. The capacity of the single capacitor can be, for example, 1000 F to 4000 F (1800 F in this example), but the present invention is not limited to this. The negative electrode terminal is connected to GND. A temperature sensor such as a thermistor is fixed to the surface of one of the four single capacitors by an adhesive. The upper limit voltage of the LIC 3 according to the present embodiment is 14.0 [V] (3.5 [V] x 4), and the lower limit voltage is 8.8 [V] (2.2 [V] x 4). ) Is set.

Each unit capacitor has a positive electrode in which a positive electrode active material containing activated carbon is applied to an aluminum foil with a large number of through holes, and a negative electrode active material capable of absorbing and releasing lithium ions in a copper foil with a large number of through holes. It has an electrode group in which a negative electrode coated with a substance (for example, amorphous carbon) and a negative electrode are wound or laminated via a microporous separator. The electrode group is infiltrated with a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a mixed solvent such as ethylene carbonate (EC), dimethyl carbonate (DMC) and diethyl carbonate (DEC). It is housed in a cylindrical, flat cylindrical, or rectangular container.

For example, when each single capacitor is a cylindrical type, the LIC 3 has a resin holder for holding four single capacitors collectively at the upper and lower positions, and these single capacitors are connected in series to each holder. A conductor for connection and a positive electrode terminal or a negative electrode terminal are built in by insert molding, and each single capacitor is a single single capacitor in which the positive and negative electrodes are arranged diagonally in the opposite direction in the vertical direction with two adjacent single capacitor It may be held by the holder in the same direction as the capacitor.

(2) Switch 6
As shown in FIG. 1, the power supply system 10 includes a switch 6 that switches charge/discharge currents of the main battery 2 and the LIC 3. The switch 6 is composed of two switches connected in series, a switch SW1 and a switch SW2. The connection point between the switch SW1 and the switch SW2 is connected to one end of the discharge load and the other end of the alternator 12. The other ends of the switches SW1 and SW2 are connected to the positive terminals of the main battery 2 and the LIC 3, respectively. The switches SW1 and SW2 are composed of switching elements (for example, power MOSFETs) capable of passing a large current.

Here, the function of the switch 6 will be described. When the regenerative power supplied from the alternator 12 is received by the power storage device 1, the switch 6 serves as a switch that connects the alternator 12 to either the main battery 2 or the LIC 3. When discharging from the electricity storage device 1 to the discharge load, it plays a role of a switch that connects the main battery 2 or the LIC 3 to the discharge load.

As shown in Table 2 below, the switch 6 has a state 0 in which the alternator 12 and the discharge load are not connected to the main battery 2 and the LIC 3, a state 1 in which the alternator 12 and the discharge load are connected to the LIC 3, the alternator 12 and the discharge. Either the state 2 in which the load is connected to the main battery 2 or the state 3 in which the main battery 2 and the LIC 3 are connected in parallel are adopted.

(3) Compensation capacitor C
When discharging from the electricity storage device 1 to the auxiliary device 14, for example, when switching from the state 1 to the state 2, there is a possibility that an electric power is not supplied to the auxiliary device 14 from either the main battery 2 or the LIC 3 for a moment. For this reason, a compensation capacitor C (electrolytic capacitor) for compensating and supplying this instantaneous power to the auxiliary device 14 is inserted between the connection point of the switches SW1 and SW2 and GND.

(4) Controllers 4, 5
The power supply system 10 also includes a main battery controller 4 and a LIC controller 5 (hereinafter, both are collectively referred to as controllers 4 and 5) that detect the states of the main battery 2 and the LIC 3, respectively. The controllers 4 and 5 detect the states of the main battery 2 and the LIC 3, such as temperature, voltage, and current, during charging/discharging (during vehicle traveling and before vehicle traveling), respectively.

That is, in the present embodiment, the temperature sensor of the main battery 2 described above is connected to the main battery controller 4, and the main battery controller 4 samples the voltage of the temperature sensor at predetermined time intervals (for example, at 10 ms intervals). The sampling result is stored in the RAM. Further, in order to detect the total voltage of the main battery 2, the positive electrode terminal and the negative electrode terminal of the main battery 2 are connected to the main battery controller 4.

Further, in order to detect the charging/discharging current flowing through the main battery 2, a current sensor 8 such as a hall element or a shunt resistor is arranged between the switch SW2 and the positive terminal of the main battery 2, and the current sensor 8 is the main battery. It is connected to the controller 4. The main battery controller 4 samples the voltage of the main battery 2 and the current flowing through the main battery 2 at predetermined time intervals (for example, at 2 ms intervals), and stores the sampling result in the RAM. Further, the main battery controller 4 detects the open circuit voltage (hereinafter, abbreviated as OCV) of the main battery 2 and the temperature at that time when charging/discharging is stopped (when the vehicle is parked).

On the other hand, the LIC controller 5 also has the same configuration as the main battery controller 3 described above (the charge/discharge current flowing through the LIC3 is detected by the current sensor 9 arranged between the switch SW1 and the positive terminal of the LIC3). , LIC3, in addition to detecting the total voltage of the LIC3, it also detects the voltage of each single capacitor in order to monitor over-discharging/over-charging. In addition, the LIC controller 5 may have a voltage adjustment circuit that adjusts (aligns) the voltages of the individual capacitors forming the LIC 3.

The controllers 4 and 5 are connected to the control unit 7 (state grasping unit 7A), and configure the temperature, voltage, current, and LIC3 of the main battery 2 and LIC3 temporarily stored in the RAM during charging/discharging. The voltage of each single capacitor is output to the control unit 7, and the detected OCV and the temperature at that time are output to the control unit 7 when charging/discharging is stopped.

(5) Control unit 7
Further, the power supply system 10 includes a control unit 7 that calculates the device states of the main battery 2 and the LIC 3, and controls the switching operation of the charging/discharging current by the switch 6. The control unit 7 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, the role of the control unit 7 is clear. The details are shown by function in order to.

The MC is a CPU that grasps (calculates) the device states of the main battery 2 and the LIC 3, a ROM that stores a basic control program and program data, a RAM that serves as a work area for the CPU and temporarily stores various data, and these. It consists of an internal bus to connect to. The internal bus is connected to the external bus, and the external bus is connected to the controllers 4 and 5 described above via the input port. Further, an output port for outputting a signal to the switch 6 and a communication IC for communicating with the vehicle control unit 15 via the I/O and the communication line 16 are connected to the external bus.

Therefore, the MC and the input port of the control unit 7 correspond to the state grasping unit 7A in FIG. 1, the MC and the output port correspond to the switch control unit 7B, and the communication IC and I/O correspond to the communication unit 7C. The control unit 7 also has other functions (for example, a function for shifting to an energy saving mode described later), but it is omitted in FIG. The switch 6 and the output port are connected by a control line, and a resistor is inserted in the control line in order to prevent the MC constituting the control unit 7 from being damaged. 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 unit of the control unit 7 will be described with reference to FIG. 1. The state grasping unit 7A temporarily stores the data output from the controllers 4 and 5 in the RAM of the MC (hereinafter, abbreviated as RAM), and then the main. The current device states (state of charge (SOC), voltage, etc.) of the battery 2 and the LIC 3 are calculated (estimated). The communication unit 7C informs the vehicle control unit 15 of the current device states of the main battery 2 and the LIC 3 calculated by the state grasping unit 7A every predetermined time (for example, 2 ms), and as described above, the vehicle control unit 15 Receives notification of vehicle status information from. The switch control unit 7B controls on/off of the switches SW1 and SW2 forming the switch 6 according to the vehicle state information notified from the vehicle control unit 15 and the device states of the main battery 2 and the LIC 3 calculated by the state grasping unit 7A. To do.

In the present embodiment, the control system constituent members (the controllers 4, 5, the switch 6, the control unit 7, the vehicle control unit 15, etc.) are operated by the electric power supplied from the main battery 2.

2. Features of Power Supply System 10 Next, features of the power supply system 10 of the present embodiment will be described.

2-1. During regenerative charging/discharging (1) When the power storage device 1 receives the regenerative power supplied from the alternator 12, the LIC 3 is charged to the use upper limit voltage V1 (see FIG. 8A, 14.0 [V] in this example). After that, the main battery 2 is charged.

(2) When the electricity storage device 1 is discharged to the auxiliary device 14, the electricity is discharged from the LIC 3 until the voltage reaches the preset voltage V2, and then the main battery 2 is discharged. The set voltage V2 is set to a voltage value equal to or higher than the lowest voltage at which the engine can be started by discharging the starter 13 from the LIC 3 (see FIG. 8A, 11.8 [V] in this example).

That is, at the time of regenerative charging/discharging, the LIC3 is charged/discharged prior to charging/discharging of the main battery 2, and at the time of regenerative discharging, the electric power of the LIC3 starts the engine, so that the voltage of the LIC3 is maintained at the set voltage V2 or higher. The machine 14 is discharged only up to the set voltage V2).

2-2. When starting the engine at idling stop start (1) At the time of idling stop start, the engine is (re)started by discharging the starter 13 from the LIC 3.

(2) Immediately after starting the engine, the main battery 2 discharges the auxiliary equipment 14. The LIC 3 is then charged with the regenerative electric power supplied from the alternator 12 (above 2-1 (1)).

2-3. During charge/discharge pause During main charge/discharge pause, the main battery 2 and the LIC 3 are connected in parallel. The main purpose of such parallel connection is to prevent over-discharging of the LIC3, but the LIC3 may be connected in parallel for the purpose of holding the voltage value equal to or higher than the set voltage V2 at which the engine can be started.

3. Operation Next, regarding the operation (charge/discharge control) of the power supply system 10 of the present embodiment, the CPU of the MC of the control unit 7 (hereinafter, abbreviated as CPU) is mainly used to perform the above “2. Features of the power supply system 10”. The contents will be specifically described.

3-1. Information sharing The vehicle control unit 15 and the control unit 7 (CPU) perform cooperative control. That is, the vehicle control unit 15 controls the vehicle according to the vehicle state and the device state of the power storage device 1, and the control unit 7 (CPU) turns on and off the switch 6 according to the vehicle state and the device state of the power storage device 1. Control. Therefore, the CPU needs the vehicle state information, and the vehicle control unit 15 needs to grasp the device state of the power storage device 1. The vehicle state information and the device state of the electricity storage device 1 are shared between the two via the above-described communication line 16. Hereinafter, shared information will be described as a premise before referring to charge/discharge control by the CPU.

(1) Vehicle status information (1-1) IGN position information Before the vehicle travels after parking the vehicle, the driver inserts an ignition key into the IGN 11, and the IGN 11 is positioned from the OFF position to the ON/ACC position, and further ON. After the engine is started by being positioned from the /ACC position to the START position, it is positioned again at the ON/ACC position. As a result, the alternator regenerative vehicle 20 is in a traveling state (while the vehicle is traveling). When the IGN 11 is first positioned in the ON/ACC position, the vehicle control unit 15 notifies the control unit 7 of that fact. Upon receiving this notification, the CPU shifts (awakens) the controllers 4 and 5 and the control unit 7 from the sleep state (energy saving mode) to the operating state.

When the vehicle is parked after traveling, the driver positions IGN 11 from the ON/ACC position to the OFF position, and the ignition key is pulled out of IGN 11. When the IGN 11 is positioned at the OFF position, the vehicle control unit 15 notifies the control unit 7 of that fact. The CPU that has received this notification shifts the controllers 4 and 5 and the control unit 7 from the awake state (operating state) to the sleep state.

The vehicle control unit 15 monitors the output of the IGN 11 and informs the control unit 7 of which position the IGN 11 is positioned as IGN position information. As shown in Table 1, the IGN position information includes OFF information indicating that the IGN 11 is located at the OFF position, ON/ACC information indicating that the IGN 11 is located at the ON/ACC position, and IGN 11 indicating that the IGN 11 is located at the START position. It includes START information indicating that it is located.

(1-2) Alternator Operation Information Since the alternator regenerative vehicle 20 has a regenerative power generation function, the vehicle control unit 15 controls the vehicle controller 15 when the brake is pressed (during braking) or when the accelerator is released (accelerator). (When it is turned off), the alternator 12 is controlled so as to shift the electromagnetic clutch to the on state to convert the driving force of the engine into regenerative electric power and supply the regenerative electric power to the power storage device 1, and notify the CPU to that effect. To do. Further, when the brake is released, or when the acceleration of the vehicle becomes 0 as a result of accelerator off, the electromagnetic clutch described above is controlled to be turned off and the operation of the alternator 12 is stopped. Notify the CPU to that effect.

That is, as shown in Table 1, when shifting the electromagnetic clutch to the ON state, the CPU is informed of the regeneration start information indicating that the supply of the regenerative electric power is started, and the electromagnetic clutch is set to the OFF state (from the ON state). When making the transition, the CPU is notified of the regeneration end information indicating that the supply of the regenerative power is finished. The alternator operation information also includes alternator start information, which will be described later.

(1-3) Idling Information Further, since the alternator regenerative vehicle 20 has the ISS function, the vehicle control unit 15 refers to the vehicle state such as brake, speed, acceleration, etc. and the device state of the power storage device 1 for idling. Determine whether to stop. Therefore, the alternator regenerative vehicle 20 is controlled by the vehicle-side control unit 15 even if the IGN 11 is positioned at the ON/ACC position while the vehicle is traveling (even if the driver does not position the IGN 11 at the OFF position or the START position). When the vehicle stops, the engine stops (idling stop), and when the accelerator is stepped on, the engine starts (re)starting (idling stop start).

As shown in Table 1, the idling information includes ISS information indicating that the alternator regenerative vehicle 20 is idling stop/start (hereinafter abbreviated as ISS), and the engine of the alternator regenerative vehicle 20 is (re)started by the ISS. Engine start information indicating that the operation has been performed is included. The vehicle control unit 15 checks the (re)starting of the engine by observing the rotation speed of the engine (crankshaft).

(2) Device State of Power Storage Device 1 The CPU configures data of the main battery 2 and LIC3 (configures LIC3) detected by the controllers 4 and 5 at predetermined time intervals during charging/discharging (before and during vehicle running). (Including the voltage value of each single capacitor), and based on the reference SOC (described later) of the main battery 2 and the LIC 3 and the capacities (known) of the main batteries 2 and LIC 3, the controllers 4 and 5 at predetermined time intervals. The current values detected are integrated to estimate (calculate) the current device states of the main battery 2 and the LIC 3. The voltage value and current value are temperature-corrected to values at a reference temperature (for example, room temperature). Then, the vehicle control unit 15 is notified of the current device states of the main battery 2 and the LIC 3 every predetermined time.

On the other hand, the vehicle control unit 15 that has received this notification refers to the current SOC and voltage value of the main battery 2 and the LIC 3, and determines whether or not to transmit the driving force of the engine to the alternator 12. For example, when the electricity storage device 1 is close to the upper limit SOC and the upper limit voltage to be used, the electromagnetic clutch is controlled so as not to operate the alternator 12 because it may fall into an overcharged state. When the SOC and the lower limit voltage for use are accelerated, the alternator 12 is operated to charge the power storage device 1 before or during the vehicle traveling without waiting for regenerative charging by the driver's brake operation or accelerator operation. To control the electromagnetic clutch.

In the case where the deterioration of the power storage device 1 is promoted, the vehicle control unit 15 should drive the engine (or stop the engine to save fuel consumption) in order to prevent the deterioration of the power storage device 1. However, the drive is continued) and the electromagnetic clutch described above is operated to connect the driving force of the engine to the alternator 12. When supplying the generated power of the alternator 12 to the electricity storage device 1 in this way, the vehicle control unit 15 uses the alternator start information (see Table 1) that indicates that the alternator 12 starts at the timing of operating the alternator 12 as the CPU. To inform. It should be noted that such power generation is a power generation method involving gasoline consumption, which is also used in conventional ordinary gasoline vehicles and the like.

3-2. Overall operation (charge/discharge control)
Next, the charge/discharge control executed by the CPU will be described with reference to the flowchart. First, an overall image of charge/discharge control executed by the CPU will be described with reference to FIG.

As shown in FIG. 2, in the charge/discharge control routine, first, in step (hereinafter, abbreviated as S) 102, the IGN position information is waited until the IGN position information is received. It is determined whether the IGN position information is ON/ACC information.

If an affirmative decision is made in S104, then in the next S106, START information has been received in order to decide whether the vehicle is in a state after traveling (before engine starting) or after traveling (after engine starting). Determine whether or not. Whether or not the START information has been received can be determined, for example, by referring to a START information reception flag described later.

If the determination in S106 is negative, the pre-engine start charge/discharge process for controlling the charge/discharge of the power storage device 1 before the engine start (before the vehicle travels) is executed (S108), and if the determination is affirmative, the engine start is performed. A regenerative charging/discharging process for controlling charging/discharging of the electricity storage device 1 afterward (while the vehicle is traveling) is executed (S110).

On the other hand, when a negative determination is made in S104, it is determined in S112 whether the received IGN position information is START information. If the determination in S112 is affirmative, for example, the START information reception flag, which was set to "0" before the engine was started, is changed to "1", and the engine is started by discharging the electricity storage device 1 to the starter 13. When the engine start process is executed (S114) and the determination in S112 is negative, that is, when the received IGN position information is OFF information, the charge/discharge pause process for suspending the charge/discharge of the electricity storage device 1 is executed. (S116).

3-3. Individual Operation (1) Charge/Discharge Processing Before Engine Start FIG. 3 is a flowchart of a charge/discharge processing subroutine before engine start showing the details of S108 of the charge/discharge control routine shown in FIG. In S152, the CPU determines whether or not the voltage of the LIC3 exceeds the set voltage V2 (see FIG. 8A). When the determination is affirmative, the switch 6 is set to the state 1 (SW1: ON, SW2: OFF). (S154). As a result, power is supplied (discharged) from the LIC 3 to the auxiliary device 14 after the vehicle is parked and before the engine is started. The determination in S152 is to keep the voltage of the LIC3 at a voltage at which the engine can be started. In the next step S156, it is determined whether or not the IGN position information is received. If the determination is negative, the process returns to step S152 to continue the power supply to the auxiliary machine 14, and if the determination is affirmative, the charge/discharge before engine start The process subroutine is terminated and the process returns to S104 of the charge/discharge control routine shown in FIG.

On the other hand, when the negative determination is made in S152, it is determined in S158 whether the SOC of the main battery 2 is the first SOC at which the engine can be started (see FIG. 8B, 70% in this example), When the determination is affirmative, the switch 6 is set to state 2 (SW1: OFF, SW2: ON) (S160). As a result, the main battery 2 supplies electric power to the auxiliary equipment 14 after the vehicle is parked and before the engine is started. In the next step S162, it is determined whether or not the IGN position information is received. If the determination is negative, the process returns to step S158 to continue the power supply from the main battery 2 to the auxiliary device 14, and if the determination is positive, the engine is The pre-start charge/discharge processing subroutine is ended and the process returns to S104 in FIG.

When a negative determination is made in S158, a charging process for charging the electricity storage device 1 is executed (S164). As described above, the vehicle-side control unit 15 determines whether to operate the alternator 12 to charge the power storage device 1. The CPU notifies the vehicle-side control unit 15 of the device state at predetermined time intervals for use in this determination. However, when a negative determination is made in S158, for example, in order to synchronize the control timing with the vehicle control unit 15, In addition to the device state, the vehicle control unit 15 may be notified that the power storage device 1 needs to be charged.

FIG. 7 is a flowchart of the charging processing subroutine showing the details of S164. The vehicle control unit 15 notifies the CPU of alternator start information at the timing of operating the alternator 12. In the following, the electric power generated by the alternator 12 in this way (in S164) is referred to as generated electric power in order to distinguish it from the regenerative electric power described above.

The CPU waits until the alternator start information is received from the vehicle control unit 15 (S302), and when receiving the alternator start information from the vehicle control unit 15, sets the switch 6 to the state 1 (S304). As a result, the LIC 3 is charged at a constant voltage with the power generated by the alternator 12. In the next step S306, it is determined whether or not the voltage of the LIC3 has been charged to the use upper limit voltage V1 (see FIG. 8A), and if the determination is negative, the LIC3 waits until it is charged to the use upper limit voltage V1. .. If IGN position information is received during this time (S308), the charging process subroutine is ended, the jump to the jump node J shown in FIG. 3 is performed, the pre-engine start charge/discharge process subroutine is also ended, and the process returns to S104 in FIG.

On the other hand, when the affirmative judgment is made in S306, the switch 6 is brought into the state 2 (S310). As a result, the main battery 2 is charged at a constant voltage with the power generated by the alternator 12. In next step S312, it is determined whether or not the main battery 2 is charged up to the second SOC (see FIG. 8B, upper limit SOC>second SOC>first SOC, 85% in this example). When the determination is negative, the main battery 2 waits until it is charged to the second SOC. If the IGN position information is received during this time (S314), the charging process subroutine is ended, the jump to the jump node J shown in FIG. 3 is performed, the pre-engine start charge/discharge process subroutine is also ended, and the process returns to S104 in FIG.

As will be described later, when charging the main battery 2 with regenerative electric power, the main battery 2 is stored with as much regenerative electric power as possible. Therefore, the main battery 2 has an upper limit SOC (see FIG. 8B, in this example, 97). %). On the other hand, when charging the main battery 2 in order to prevent deterioration of the main battery 2, it is necessary to operate the alternator 12. As described above, the operation of the alternator 12 involves gasoline consumption because the driving force of the engine is connected to the alternator 12. Therefore, it may be charged from the first SOC (70%) to the upper limit SOC (97%), but if it is charged up to the preset second SOC (85%), then the main battery is regenerated by the regenerative power. Since the 2 may be charged further, gasoline consumption can be saved (fuel consumption can be improved).

When an affirmative determination is made in S312 (when the main battery 2 is charged to the second SOC), the charging process subroutine is ended and the process returns to S152 of the pre-engine start charge/discharge process subroutine shown in FIG.

(2) Engine Starting Process As described above, after the IGN 11 is positioned at the ON/ACC position, it is positioned at the START position and the engine is started. FIG. 4 is a flowchart of an engine start processing subroutine showing the details of S114 of the charge/discharge control routine shown in FIG.

As shown in FIG. 4, in S182, the CPU determines whether or not the voltage of the LIC3 is equal to or higher than the set voltage V2 at which the engine can be started. When the determination is affirmative, the switch 6 is set to the state 1 and the LIC3 is changed to the starter 13. Electric power is supplied (discharged) (S184), and when the determination is negative, the switch 6 is set to state 2 and electric power is supplied from the main battery 2 to the starter 13 (S186) to start the engine. As described above, the driver positions the IGN 11 at the ON/ACC position after the IGN 11 is positioned at the START position and starts the engine (exceptionally, the IGN 11 may be positioned at the OFF position). In the next step S188, the IGN position information is waited until it is received. When the IGN position information is received, the engine start subroutine is terminated and the process returns to step S104 in FIG.

Therefore, when the engine is started after the vehicle is parked and before traveling of the vehicle, (a) when the voltage of the LIC3 is equal to or higher than the set voltage V2, the engine is started by discharging the starter 13 from the LIC3, and (b) of the LIC3. The voltage is less than the set voltage V2, and the SOC of the main battery 2 is discharged from the main battery 2 to the starter 13 so that the engine can be started (the first SOC in FIG. 8B, 70% in this example). In the above case, the engine is started by discharging the starter 13 from the main battery 2, and (c) when the voltage of the LIC 3 is less than the set voltage V2 and the SOC of the main battery 2 is less than the first SOC, the LIC 3 and After charging the main battery 2 with the power generated by the alternator 12 (see S164 in FIG. 3), the engine is started by discharging the LIC 3 to the starter 13. That is, the LIC 3 discharges the starter 13 as much as possible.

(3) Regenerative charging/discharging control Since the control content of the regenerative charging/discharging control is a little complicated, the points of the regenerative charging/discharging control are summarized below ((3-1) and (3-2) below), then the regenerative charging/discharging control is performed. The discharge process (S110 of FIG. 2) will be described ((3-3) below).

(3-1) Regenerative charging control When the CPU receives the regeneration start information from the vehicle control unit 15, the CPU controls the switch 6 so that the LIC 3 is charged up to the use upper limit voltage V1 (the switch 6 is set to state 1). ..). As a result, the LIC3 is charged with a constant voltage up to the use upper limit voltage V1. However, if regenerative end information is received from the vehicle control unit 15 before the LIC3 reaches the use upper limit voltage V1, regenerative power is not supplied, and at that point, charging of the LIC3 is terminated and the LIC3 immediately terminates the auxiliary equipment. The switch 6 is controlled so as to be discharged to 14 (the switch 6 remains in the state 1).

When the LIC 3 is charged up to the use upper limit voltage V1, the CPU controls the switch 6 so that the main battery 2 is charged up to the use upper limit SOC in principle (the switch 6 is in the state 2). As a result, the main battery 2 is charged up to the upper limit SOC. However, when regenerative end information is received from the vehicle control unit 15 before the main battery 2 reaches the upper limit SOC, regenerative power is not supplied, so that charging of the main battery 2 is stopped at that point and the LIC3 is immediately released. The switch 6 is controlled so as to be discharged from the auxiliary device 14 to the auxiliary device 14 (the switch 6 is set to the state 1).

When the main battery 2 is charged to the upper limit SOC, the CPU controls the switch 6 so as to stop the charging of the main battery 2 in order to avoid overcharging the main battery 2 (set the switch 6 to the state 0). ..).

(3-2) Regenerative Discharge Control (3-2-1) During Regenerative Discharge When the CPU receives the regeneration end information from the vehicle control unit 15, the LIC3 is set in the auxiliary device 14 as a rule, the LIC3 is set in advance. The switch 6 is controlled so as to be discharged until the voltage becomes V2 (see FIG. 6A) (the switch 6 is set to the state 1). However, if regenerative start information is received from the vehicle control unit 15 before the LIC3 reaches the set voltage V2, regenerative electric power is supplied, and at that time, the discharge from the LIC3 to the auxiliary device 14 is stopped and immediately. The switch 6 is controlled so that the LIC 3 is charged with the regenerative electric power (the switch 6 is kept in the state 1).

When the LIC3 is discharged to the set voltage V2, the CPU controls the switch 6 so that the main battery 2 is discharged to the first SOC (see FIG. 6B) in principle (the switch 6 is in the state 2). And). However, when the regeneration start information is received from the vehicle control unit 15 before the main battery 2 becomes the first SOC, regenerative electric power is supplied, so that the main battery 2 transfers to the auxiliary device 14 at that time. The discharge is stopped, and the switch 6 is controlled so that the LIC 3 is immediately charged with the regenerative power (the switch 6 is set to the state 1). The reason why the LIC3 is discharged only to the set voltage V2 (not to the use lower limit voltage V4) is to keep the LIC3 at a voltage at which the engine can be started in preparation for the ISS.

(3-2-2) At ISS When the CPU receives the ISS information, the LIC3 is maintained at the voltage equal to or higher than the set voltage V2 even during the regenerative discharge (during ISS, the idling stop immediately before that is performed. Unless there is a large discharge to the auxiliary machine 14 due to the regenerative power, the LIC3 has a voltage near the upper limit voltage of use V1.), and the LIC3 discharges the starter 13 to start the engine. During the period from the reception of the ISS information to the reception of the next engine start information, the engine start by the power of the LIC3 is prioritized, and the switching control of the switches SW1 and SW2 forming the switch 6 is not performed. Therefore, the ISS information functions as information for the CPU to prohibit the switching of the switch 6 (command to continue the switch state).

When the engine start is successful, the vehicle control unit 15 notifies the CPU of the engine start information. Upon receiving the engine start information, the CPU controls the switch 6 so that the main battery 2 is discharged to the auxiliary device 14 (the switch 6 is set to the state 2). The reason for this is to prevent the LIC3 from deteriorating because the voltage of the LIC3 has dropped due to the large current discharge to the starter 13 when the engine is started, and to switch the discharge to the auxiliary machine 14 from the LIC3 to the main battery 2. This is to suppress the capacity of the LIC 3 and prevent an increase in cost. The LIC 3 is charged by the regenerative power of the alternator 12 thereafter.

Here, with reference to FIG. 8A, the amount of electric power of the LIC 3 necessary for starting the engine of the ISS will be described.

The closer the set voltage V2 is to the lower limit voltage of use V1, the higher the utilization efficiency of regenerative power can be. On the other hand, the closer the set voltage V2 is to the lower limit voltage V1, the larger the capacity of the LIC3 is required for starting the engine, and the cost of the power supply system 10 increases. Therefore, in the power supply system 10 of the present embodiment, the voltage drop (on the lowest voltage side) due to the discharge to the starter 13 (and the auxiliary machine 14) of the LIC 3 at the time of engine start of ISS is set to 3.0 [V]. Is designed. As described above, since the use lower limit voltage V4 of the LIC3 is set to 8.8 [V], the minimum voltage required for starting the engine of the LIC3 is 11.8 [V]. 8 [V] is set voltage V2.

If the average voltage of the LIC3 at the time of engine start during ISS is set to an intermediate value between the set voltage V2 (11.8 [V]) and the use lower limit voltage V1 (8.8 [V]), the LIC3 at engine start The voltage is 10.3 [V]. Although it is affected by the displacement of the engine used and the specifications of the starter, for example, if the current flowing through the starter 13 at engine start is about 300 [A] and the time at engine start is about 1 [s], the minimum The electric energy of the LIC3 necessary for starting the engine on the voltage side is 300 [A]×10.3 [V]×(1 [s]/3600)≈0.86 [Wh]. Each unit capacitor shares this amount of electric power (0.22 [Wh] of 1/4).

Further, when the engine is started, the switch 6 is set to the state 1, and electric power is also supplied from the LIC 3 to the auxiliary machine 14 (in particular, the engine pump). Therefore, it is necessary to consider the allowance. Furthermore, it is preferable to have an amount of power that can be retried even if the engine start fails. From such a background, in the present embodiment, the single capacitor is set to the above-mentioned capacitance from the safety side.

(3-3) Regenerative Charge/Discharge Processing Based on the above, the regenerative charge/discharge control by the CPU will be described with reference to the regenerative charge/discharge processing subroutine shown in FIG. The contents overlapping with the control contents described in (3-1) and (3-2) above will be described as briefly as possible.

As shown in FIG. 5, in the regeneration charge/discharge processing subroutine, the process waits until the regeneration start information (S202) or the regeneration end information (S224) is received from the vehicle control unit 15.

When the determination in S202 is affirmative (when the regeneration start information is received), the switch 6 is set to state 1 (S204). As a result, the LIC 3 is charged with a constant voltage by regenerative power. Next, in S206, it is determined whether or not the IGN position information is received. If the determination is affirmative, the regenerative charge/discharge processing subroutine is terminated and the process returns to S104 in FIG. 2, and if the determination is negative, In the next step S208, it is determined whether or not the regeneration end information is received. If the determination is affirmative, the process proceeds to step S226 (charging to the LIC3 is terminated). If the determination is negative, the voltage of the LIC3 is determined in the next step S210. It is determined whether or not the usage upper limit voltage V1 is reached. When the determination in S210 is negative, the process returns to S206 in order to continue the reception of the regenerative power by the LIC 3, and when the determination is affirmative, the switch 6 is set to state 2 (S212). As a result, the main battery 2 is charged at a constant voltage with regenerative power.

Next, in S214, it is determined whether or not the IGN position information is received. If the determination is affirmative, the regenerative charging/discharging processing subroutine is terminated and the process returns to S104 in FIG. 2, and if the determination is negative, the next S216 is performed. , Determines whether or not the regeneration end information has been received. If the determination is affirmative, the process proceeds to S226 (charging to the main battery 2 is terminated), and if the determination is negative, the main battery 2 is used at the next S218. It is determined whether or not the upper limit SOC (see FIG. 8B) is reached.

When the determination in S218 is negative, the process returns to S214 to continue the reception of the regenerative power by the main battery 2, and when the determination is affirmative, the switch 6 is set to the state 0 (to prevent overcharge of the main battery 2). SW1: OFF, SW2: OFF) (S222). As a result, the main battery 2 is no longer charged with regenerative power. Next, in S222, it is determined whether or not the IGN position information is received. If the determination is negative, the process returns to S202, and if the determination is affirmative, the regenerative charging/discharging process subroutine is terminated and the process returns to S104 in FIG.

On the other hand, when an affirmative determination is made in S224 (when the regeneration end information is received), the switch 6 is set to state 1 (S226). As a result, the electric power of the LIC 3 is supplied to the auxiliary device 14. Next, in S228, it is determined whether or not the IGN position information is received. If the determination is affirmative, the regenerative charge/discharge processing subroutine is ended and the process returns to S104 in FIG. 2, and if negative, the next S230. At, it is determined whether or not the regeneration start information is received.

When the determination in S230 is affirmative, the process returns to S204 (discharging from the LIC 3 to the auxiliary device 14 is terminated), and when the determination is negative, it is determined in the next S232 whether ISS information is received. When the determination in S232 is affirmative, the process stands by until the engine start information is received in S236 (during which the LIC 3 discharges the starter 13 and the engine is (re)started), and when the engine start information is received, the process proceeds to S238. .. On the other hand, when the determination in S232 is negative, it is determined in the next S234 whether or not the voltage of the LIC3 has become the set voltage V2. When the determination is negative, the voltage of the LIC3 can be maintained at the set voltage V2 at which the engine can be started even if the auxiliary device 14 is discharged from the LIC3. Therefore, the process returns to S228, and when the determination is affirmative, the voltage of the LIC3 is set to the set voltage. In order to maintain V2, the process proceeds to S238 (the discharge from LIC3 to auxiliary device 14 is stopped).

In S238, the switch 6 is set to state 2. As a result, the power of the main battery 2 is supplied to the auxiliary device 14 (the power supply to the auxiliary device 14 is switched from the LIC 3 to the main battery 2). Next, in S214, it is determined whether or not the IGN position information is received. If the determination is affirmative, the regenerative charging/discharging process subroutine is terminated and the process returns to S104 in FIG. 2, and if the determination is negative, In the next step S242, it is determined whether or not the regeneration end information is received. If the determination is affirmative, the process returns to step S204 (discharging from the main battery 2 to the auxiliary device 14 is terminated), and if the determination is negative, the next In S244, it is determined whether the main battery 2 has become the first SOC (see FIG. 8B). If the determination is negative, the process returns to S240 to continue discharging from the main battery 2 to the auxiliary device 14, and if the determination is positive, the charging process for charging the power storage device 1 is executed in S246. The details of S246 are as already described with reference to FIG.

(4) Charge/Discharge Pause Processing FIG. 6 is a flowchart of the charge/discharge pause processing subroutine showing the details of S116 of the charge/discharge control routine shown in FIG. In this state, the alternator regenerative vehicle 20 is parked, and the CPU that has received the OFF information from the vehicle control unit 15 sets the switch 6 to the state 0 (SW1: OFF, SW2: OFF) to set the controllers 4, 5 and the control unit 7. Is controlled to a sleep state (energy saving mode) (S282). That is, the controllers 4 and 5 are made to stop the detection/output of the temperature, voltage, current, etc. of the main battery 2 and LIC 3, and the CPU itself is also made to stop the calculation of the device state of the main battery 2 and LIC 3 and the notification to the vehicle control unit 15. To do.

The power storage device 1 is charged with the regenerative electric power by the alternator 12 immediately before the vehicle is parked, and the LIC 3 has a voltage near the use upper limit voltage V1. In S282, the START information reception flag described above is changed from "1" to "0".

Next, it waits until a predetermined time has elapsed since the OFF information was received (S284). This predetermined time can be set to, for example, 6 hours when it is considered that the polarization state of the negative electrode of the main battery 2 has been eliminated. During this time, when the IGN position information is received (S286), the charge/discharge pause processing subroutine is ended and the process returns to S104 in FIG.

When the CPU determines that the predetermined time has elapsed, it awakens the controller 4, 5 and the control unit 7 (shifts to the operating state) to detect and output the OCV of the main battery 2 and the LIC 3 and the temperature at that time. Then, the SOC and voltage of the main battery 2 and the LIC 3 are calculated from the OCV of the main battery 2 and the LIC 3, and the SOC and the voltage calculated by referring to the table or the formula stored in the ROM in advance as the program data and expanded in the RAM are used as the reference. The SOC at the temperature (for example, room temperature) is temperature-corrected to calculate (calculate) the reference SOC of the main battery 2 and the LIC 3, and the calculated reference SOC and voltage are notified to the vehicle control unit 15 (S228).

In this case, the health status (SOH) of the main battery 2 and the LIC 3 may also be calculated, and the SOC may be corrected according to the SOH. If the above-mentioned predetermined time does not elapse, the polarization state of the main battery 2 is not resolved and the reference SOC becomes inaccurate. Therefore, in such a state, the OCV is detected by the controllers 4 and 5 and the reference by the CPU is determined. The SOC is not calculated, and the reference SOC that was most recently grasped is treated as the reference SOC when grasping the current device state.

Next, the CPU determines whether the voltage of the LIC3 is equal to or higher than a preset voltage V3 (see FIG. 8A, use lower limit voltage V4<set voltage V3<set voltage V2, 9.3 [V] in this example). Determine whether or not. When the determination is affirmative, the controllers 4 and 5 and the control unit 7 are put into the sleep state, and it is determined in S298 whether or not the IGN position information is received. When the determination is affirmative, the charge/discharge pause processing subroutine is terminated and the process returns to S104 in FIG. 2, and when the determination is negative, the process returns to S284.

On the other hand, when a negative determination is made in S290 (strictly speaking, the SOC of which the voltage of the LIC3 is less than the set voltage V3 and the voltage of the main battery 2 is V3 or more and the main battery 2 can charge the LIC3 (see, for example, FIG. (When the SOC is equal to or higher than the first SOC shown in B)), the switch 6 is set to the state 3 (SW1: ON, SW2: ON) in order to prevent over-discharging of the LIC 3 (S292). As a result, the main battery 2 and the LIC 3 are connected in parallel, and the LIC 3 is charged with the power of the main battery 2.

When the voltage of the LIC3 becomes the set voltage V3 due to the parallel connection with the main battery 2 (S296), the CPU puts the controllers 4 and 5 and the control unit 7 in the sleep state and returns to S282. During this time, when the IGN position information is received (S294), the charge/discharge pause processing subroutine is ended and the process returns to S104 of FIG.

When the IGN 11 is positioned at the OFF position after the vehicle has run, the vehicle control unit 15 also performs predetermined processing (data storage, etc.) and then enters a sleep state, and operates only when the control unit 7 notifies the OCV and the temperature. It becomes a state.

In the above description, the voltage of the LIC3 is mainly described in order to briefly describe the charge/discharge control by the CPU. However, in the present embodiment, the upper limit/lower limit SOC of the LIC3 and the upper limit/use limit of each single capacitor forming the LIC3 are used. The lower limit voltage and the use upper limit/lower limit SOC are also preset, and when the LIC 3 reaches the use upper limit SOC, the LIC 3 is terminated and the main battery 2 is charged, and the LIC 3 uses the use lower limit SOC and each single capacitor. When the SOC reaches the lower limit SOC, the discharge from the LIC 3 to the auxiliary device 14 is stopped, and the control to discharge from the main battery 2 to the auxiliary device 14 is also performed. The upper limit voltage and lower limit voltage of the main battery 2 are set similarly to the LIC 3, and the charging/discharging control of the main battery 2 is also performed according to the upper limit voltage and the lower limit voltage of use like the LIC 3. ..

4. Effects, etc. 4-1. Functions and Effects Next, functions and effects of the power supply system 10 of the present embodiment will be described.

In the power supply system 10 of the present embodiment, when regenerative power is received, the LIC 3 having a high charge acceptability is charged up to the use upper limit voltage V1 prior to the main battery 2 (S210), and when the auxiliary battery 14 is discharged, the main battery 2 is discharged. Prior to No. 2, the LIC3, which has an excellent large current discharge characteristic, is discharged until the voltage reaches the set voltage V2 at which the engine can be started (S234). For this reason, the utilization efficiency of the regenerative electric power supplied from the alternator 12 can be improved, and the fuel consumption of the alternator regenerative vehicle 20 can be improved.

Further, in the power supply system 10 of the present embodiment, when the engine is started, the LIC 3 discharges the starter 13 (S226, S232). In addition to this, as described above, when the regenerative power is received, the LIC 3 is charged prior to the main battery 2, and when the auxiliary device 14 is discharged, the LIC 3 is discharged before the main battery 2. The charge and discharge opportunities of are reduced. Therefore, the deterioration of the main battery 2 can be prevented and the shortening of the life can be suppressed.

Furthermore, in the power supply system 10 of the present embodiment, when the engine start information is received, the discharge to the auxiliary device 14 is switched from the LIC 3 to the main battery 2 (S238). Therefore, it is possible to prevent the deterioration of the LIC3, suppress the capacity of the LIC3, and prevent the cost increase of the power supply system 10.

Further, in the power supply system 10 of the present embodiment, at the time of ISS, the LIC 3 having excellent large current discharge characteristics is discharged to the starter 13 (S226, S232, S236). Therefore, the certainty of engine restart can be enhanced, and the driver's anxiety about the inability to restart the engine when idling is stopped can be eliminated.

Further, in the power supply system 10 of the present embodiment, the main battery 2 and the LIC 3 are connected in parallel when charging/discharging is suspended (S292). Therefore, it is possible to prevent deterioration of the LIC3 due to over-discharge.

4-2. Modifications In the present embodiment, an example in which the power supply system 10 is integrated and mounted in the engine room is shown, but the present invention is not limited to this. For example, the main battery 2 forming the power storage device 1 may be arranged in the engine room, and the LIC 3 forming the power storage device 1 may be divided and arranged under the seat. Further, the switches SW1 and SW2 forming the control unit 7 and the switch 6 may be divided and arranged according to the arrangement of the electricity storage device 1 as described above.

Further, in the present embodiment, an example is shown in which the main battery 2 and the LIC 3 are connected in parallel at the time of charging/discharging suspension in order to prevent over-discharging of the LIC 3 (S292), but the present invention is not limited to this. Absent. For example, when charging/discharging is stopped, the voltage of the LIC3 is less than the set voltage V2 and the voltage of the main battery 2 is V2 or more (and the SOC by which the main battery 2 can charge the LIC3 (for example, the SOC of the third SOC or more) is determined). In the case of having), the main battery 2 may charge the LIC 3 until the voltage of the main battery 2 is reached. In such control, the engine can be started by discharging the starter 13 from the LIC 3 in the engine starting process before the vehicle travels, so that deterioration of the main battery 1 is prevented (since the main battery 1 is not used for engine starting). be able to.

Furthermore, in the present embodiment, since the LIC3 has high charge acceptability and can be charged in a short time, the LIC3 is used when the main battery 2 is charged even if the LIC3 has the set voltage V2 at which the engine can be started. Although an example of charging up to the upper limit voltage V1 has been shown (S306 in S164 and S246), only the main battery 2 may be charged without charging the LIC3.

Furthermore, in the present embodiment, the lead battery is illustrated as the main battery 2, but the present invention is not limited to this. For example, a nickel-hydrogen battery, a nickel-zinc battery, or a lithium-ion battery can be used instead of the lead storage battery. It should be noted that the lithium-ion capacitor is generally superior to the lithium-ion battery in large-current discharge characteristics (when the ISS is started) for structural reasons.

Further, in the present embodiment, the compensation capacitor C is illustrated in order to prevent the auxiliary device 14 from being supplied with power from neither the main battery 2 nor the LIC 3, but the present invention is not limited to this. .. For example, the switches SW1 and SW2 may be simultaneously turned on (state 3) for a moment, or a primary battery or a secondary battery may be used instead of the compensation capacitor C.

Further, in the present embodiment, an example in which the current SOC of the main battery 2 and the LIC 3 is estimated by calculating the reference SOC from the OCV and integrating the charge/discharge current with respect to the reference SOC has been described. It is not limited, and a known SOC estimating means can be used.

Further, in the present embodiment, the main battery controller 4, the LIC controller 5, and the control unit 7 are separately described so that the configuration of the power supply system 10 can be easily grasped, but these may be integrally configured. Further, in the present embodiment, an example in which the control unit 7 calculates the device states of the main battery 2 and the LIC 3 according to the data of the main battery 2 and the LIC 3 output from the controllers 4 and 5 has been described. May be performed by the vehicle control unit 15. In such an aspect, the main functions of the control unit 7 are the switch control unit 7B and the communication unit 7C.

Furthermore, in the present embodiment, an example in which the OCV of the main battery 2 and the LIC 3 is measured 6 hours after receiving the OFF information according to the lead storage battery constituting the main battery 2 has been shown, but the present invention is not limited to this. Not something. In addition, in the present embodiment, an example in which the CPU of the control unit 7 measures 6 hours has been described, but the vehicle control unit 15 may measure the time and awaken the control unit 7 and the controllers 4 and 5 from the sleep state. Good.

Further, in the present embodiment, the control unit 7 shows an example in which the alternator operation information and the IGN information are acquired via the vehicle control unit 15, but the present invention is not limited to this, and for example, brake control for controlling a brake. Alternatively, the brake operation information, the alternator operation information, the IGN position information, and the like may be directly acquired from the IGN 11 and the alternator control unit that controls the alternator.

Further, in the present embodiment, the operating voltage of each member constituting the power supply system 10 and the like, the set voltages V2 and V3 of the LIC3, the upper limit SOC of the main battery 2 and the first and second SOCs are illustrated in FIG. However, the present invention is not limited to this.

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

The present invention provides a vehicle power supply system capable of suppressing the shortening of the life of the secondary battery while improving the utilization efficiency of regenerative power, and a vehicle equipped with the power supply system. It has industrial applicability as it contributes to sales.

1 Composite power storage device 2 Main battery (secondary battery)
3 Lithium Ion Capacitor (LIC)
6 switches (switch means)
7 Control unit (control means)
7C communication unit (acquisition means)
10 Power Supply System 11 Ignition Switch 12 Alternator 13 Starter (Starter for Engine Start)
14 Auxiliary equipment 20 Alternator regenerative vehicle (automobile)

Claims (10)

A composite power storage device having a secondary battery and a lithium ion capacitor (LIC), capable of receiving regenerative power supplied from an alternator, and capable of discharging a starter for starting an engine and an auxiliary machine,
Switch means for switching charging/discharging current of the secondary battery and the LIC;
Control means for controlling the switch means based on the voltage of the LIC;
Equipped with
The control means is
When the power storage device receives the regenerated power, the LIC is charged to a preset use upper limit voltage V1, and then the secondary battery is charged.
When the electricity storage device discharges to the auxiliary device, after discharging from the LIC until the voltage reaches a preset setting voltage V2, then discharging from the secondary battery,
When starting the engine, discharge from the LIC to the starter ,
Controlling the switch means to discharge from the LIC to the starter and the auxiliary machine at the time of engine start at the time of idling stop start ,
The set voltage V2 is set to a voltage value higher than a preset lower limit voltage of use V4 of the LIC by a voltage drop caused by discharge of the LIC to the starter and the auxiliary machine.
Vehicle power supply system. The vehicle power supply system according to claim 1, wherein the LIC has an amount of electric power that can be retried even if the engine start fails . The control means is
When the electricity storage device receives the regenerated electric power, after charging the LIC to a preset upper limit of use voltage V1, the secondary battery is charged to a preset upper limit of use charge state,
When the electricity storage device discharges to the auxiliary device, after discharging from the LIC until the voltage reaches a preset setting voltage V2, then discharging from the secondary battery,
When the state of charge of the secondary battery is lowered to a preset first state of charge, the discharge to the auxiliary machine is stopped, and the LIC is charged to a preset use upper limit voltage V1 before the secondary battery is charged. The switch means is controlled so as to charge up to a preset second charging state (where the first charging state<the second charging state<the use upper limit charging state) .
The power supply system for a vehicle according to claim 1 or 2. Further comprising an acquisition means for acquiring vehicle state information,
From the time the acquisition means acquires the idling stop start information indicating that the vehicle starts idling stop to the time when the control means acquires the engine start information indicating that the engine has started by the idling stop start. The vehicle power supply system according to claim 4, wherein the switch means is controlled so as to maintain a switch state in which the LIC discharges the starter and the auxiliary machine. The vehicle according to claim 4, wherein the control unit controls the switch unit so that the secondary battery is discharged to the auxiliary device when the acquisition unit acquires the engine start information. Power system. The vehicle according to any one of claims 1 to 5, wherein the control unit controls the switch unit so that the secondary battery and the LIC are connected in parallel when charging/discharging is suspended. Power system. The control means is configured such that the voltage of the LIC is less than a preset voltage V3 (however, the lower limit voltage V4 of the LIC is less than the use lower limit voltage V4<the set voltage V3<the set voltage V2) and the voltage of the secondary battery is the set voltage V3. 7. The vehicle power supply system according to claim 6, wherein the switch means is controlled so that the secondary battery and the LIC are connected in parallel at the above time. The control means controls the switch means to connect the secondary battery and the LIC in parallel when the voltage of the LIC is less than the set voltage V2 and the voltage of the secondary battery is the set voltage V2 or more. The power supply system for vehicles according to claim 6 or 7, which is controlled. 9. The secondary battery according to claim 1, wherein the secondary battery is one kind selected from the group consisting of a lead storage battery, a nickel hydrogen battery, a nickel zinc battery and a lithium ion battery. The vehicle power supply system described. An automobile comprising the vehicle power supply system according to any one of claims 1 to 9.

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