JP6428086B2 - Power supply system and automobile - Google Patents

Description

  The present invention relates to a power supply system and an automobile, and more particularly, to a power supply system equipped with a power storage device mounted on a vehicle and capable of receiving regenerative power supplied from an alternator and capable of discharging to a discharge load, and an automobile equipped with the power supply system. .

  Conventionally, in mobile objects such as automobiles (vehicles), as is the case with ordinary gasoline cars, the electric power supplied from the alternator is charged to an electricity storage device such as a lead-acid battery during traveling except during braking, so that the electricity storage device is almost satisfied. The battery was kept charged. In recent years, from the viewpoint of suppressing carbon dioxide emissions, the number of vehicles (ISS vehicles) having an idling stop system (ISS) function is gradually increasing in such gasoline vehicles.

  In ISS vehicles, the engine is stopped when the vehicle is stopped (thus, charging from the alternator to the power storage device is also stopped), and all power supply to the auxiliary equipment such as lamps and electrical equipment in the meantime is covered by the power storage device. At the start after the stop, the engine is started by driving a starter (cell motor) with the electric power stored in the electric storage device. 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 economy has been particularly high thanks to the rise in the retail price of gasoline, and the number of vehicles with high fuel efficiency has increased 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 an alternator regenerative vehicle includes a vehicle having the above-described ISS function, and such a vehicle is sometimes called a μHEV or a micro hybrid.

  In an alternator regenerative vehicle, the energy storage device is charged with the regenerative power supplied from the alternator, which was consumed by heat from an ordinary gasoline vehicle, and the operation of the alternator is basically stopped during operation except during braking (power storage device). (To stop charging) to reduce gasoline consumption by the engine to operate the alternator and improve fuel efficiency. All power supply to the discharge load while the alternator is stopped is covered by the electricity storage device. When the state of charge (SOC) of the power storage device is equal to or lower than a predetermined set value, the power storage device is charged by operating the alternator during or before traveling in order to prevent overdischarge of the power storage 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 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.

Japanese Unexamined Patent Publication No. 2003-134589 (paragraphs “0030” to “0034”, see FIG. 1)

Takafumi Kondo et al., Development of battery for alternator regenerative vehicle, Shin-Kobe Technical Report No. 18 (2008-2)

  By the way, in the technique of Patent Document 1, when the voltage value of the regenerative power from the generator (motor generator) reaches the acceptance upper limit voltage value of the lithium ion battery (sub-battery), charging of the power storage device by the regenerative power is performed. Control is performed to switch from a lithium ion battery to a lead storage battery (main battery) (see paragraph “0032”). Here, even if the voltage value of the regenerative power reaches the acceptance upper limit voltage value of the sub battery, if the sub battery can be continuously charged with that voltage, the charging efficiency of the entire power storage device, and thus the vehicle The fuel efficiency improvement rate can be improved. Also, in a temperature environment exceeding -15 ° C, the electric power once stored in the lithium ion battery (sub battery) remains stored in the sub battery during charging / discharging (during traveling), and when charging / discharging is stopped (when the vehicle is parked) ) Is controlled to be moved to a lead storage battery (main battery) (see paragraphs “0033” and “0034”). Here, if the power stored in the sub-battery can be discharged to the discharge load without waiting for the charging / discharging pause, the utilization efficiency (discharge efficiency) of the entire power storage device, and thus the fuel efficiency improvement rate of the vehicle can be improved. Can be improved.

  An object of the present invention is to provide a power supply system capable of improving the fuel efficiency improvement rate and an automobile equipped with the power supply system.

In order to solve the above problems, a first aspect of the present invention is mounted on a vehicle, in the power supply system including a dischargeable power storage device to be the regenerative electric power receivable and discharge load supply from the alternator, the engine start a first power storage device use, the state of charge of the second power storage device and a switch means for switching the charging and discharging currents of the first and second power storage devices, said first and second power storage devices (SOC) And a control means for controlling a current switching operation by the switch means based on the SOC of the second power storage device estimated by the SOC estimation means, and the control means comprises: When regenerative power is received by the power storage device, the second power storage device is charged to the upper limit of use SOC, and then the first power storage device is charged. And, when a discharge in the discharge load from the electric storage device, after the second power storage device is discharged to the first SOC to a predetermined, discharged from said first power storage device, the first When the power storage device is discharged to a predetermined second SOC having an SOC of 70% or more, the first power storage device is determined to be a predetermined third SOC less than the upper limit SOC of the first power storage device. The switch means is controlled so as to charge the battery .

In the first aspect, in order to increase the utilization efficiency of the power storage device by regenerative power, the control means discharges until the second power storage device reaches the use lower limit SOC when discharging from the power storage device to the discharge load. The switch unit may be controlled to discharge from one power storage device .

  Further, the control means includes an acquisition means for acquiring regeneration start information indicating that the supply of regenerative power by the alternator starts from the vehicle side and regeneration end information indicating that the supply of regenerative power by the alternator ends. When the acquisition means acquires the regeneration start information, the switch means is controlled to start charging the second power storage device with the regenerative power, and when the acquisition means acquires the regeneration end information, the second to th The switch means may be controlled so that the charging of the first power storage device is discontinued and the second power storage device is discharged to the discharge load.

  The first power storage device is one selected from the group consisting of a lead storage battery, a nickel metal hydride battery, a nickel zinc battery, and a lithium ion battery, and the second power storage device is a lead storage battery, a nickel metal hydride battery, and a nickel zinc battery. , One selected from the group consisting of a lithium ion battery, a lithium ion capacitor, and an electric double layer capacitor.

  Moreover, in order to solve the said subject, the 2nd aspect of this invention is a motor vehicle provided with the power supply system of the 1st aspect.

According to the present invention, when the control unit accepts the regenerative power by the power storage device, after charging the second power storage device to the use upper limit SOC, the first power storage device is charged and discharged from the power storage device to the discharge load. At this time, after the second power storage device is discharged until the first SOC is reached, the first power storage device is discharged, and the first power storage device is discharged to a predetermined second SOC with an SOC of 70% or more. The switching means is controlled so as to charge the first power storage device to a predetermined third SOC lower than the upper limit SOC of the first power storage device, so that it is possible to wait for the charge / discharge pause without waiting. Since the electric power stored in the electric storage device 2 can be discharged to the discharge load, the utilization efficiency of the entire electric storage device can be improved, and the fuel efficiency improvement rate of the vehicle can be improved. It is possible to obtain.

1 is a block circuit diagram of a power supply system according to an embodiment to which the present invention is applicable. It is explanatory drawing which shows typically the mounting position of the power supply system of this embodiment in an alternator regeneration vehicle. It is explanatory drawing which shows the connection state of a selector typically, (A) shows state "0", (B) shows state "1", (C) shows state "2". It is a flowchart of the charging / discharging control routine which CPU of the microcontroller of a control part 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 this embodiment, (A) shows the charge state of a sub battery, (B) shows the charge state of the main battery.

  Hereinafter, an 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, and includes an accelerator, a brake, an engine, and the like. The operation state, speed, acceleration and other vehicle states are grasped, and traveling control is performed according to the grasped state. In addition, 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. 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. In the present embodiment, the upper limit of the output voltage of the alternator 12 is set to 14V. One end of the alternator 12 is connected to the ground (the same potential as the vehicle chassis; hereinafter abbreviated as GND), and the other end is connected to one end of a discharge load 14 and one side end of the selector 5 which will be described later. ing.

<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.

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

(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 an electricity storage device that can accept regenerative power supplied from an alternator 12 and can discharge to a discharge load 14. The power storage device includes a main battery 1 (first power storage device) composed of an aqueous or non-aqueous battery, and a sub battery 2 (second power storage device) composed of an aqueous or non-aqueous battery or a capacitor. It is configured. In the present embodiment, the “main battery” refers to a battery for starting the engine, and the “sub battery” refers to any other battery or capacitor.

  For the main battery 1, for example, one type selected from the group consisting of a lead storage battery, a nickel hydride battery, a nickel zinc battery, and a lithium ion battery (LIB) can be used. One type selected from the group consisting of a lead storage battery, a nickel metal hydride battery, a nickel zinc battery, a lithium ion battery, a lithium ion capacitor (LIC), and an electric double layer capacitor can be used. In the present embodiment, the sub battery 2 receives regenerative power prior to the main battery 1 and discharges it to the discharge load 14. Therefore, the sub battery 2 has charge acceptability equal to or higher than the charge acceptability for the regenerative power of the main battery 1. (The internal resistance of the sub battery 2 is smaller than the internal resistance of the main battery 1). In the following, in order to simplify the description, an example in which a lead storage battery is used for the main battery 1 and a lithium ion battery is used for the sub battery 2 will be described. In addition, the power supply system 10 of this embodiment comprises the 14V type | system | group power supply system.

<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, and 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, and 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 has a positive electrode terminal on the highest potential side and a negative electrode terminal on the lowest potential side by connecting, for example, a plurality of (four in this example) 4V lithium ion batteries in series. The negative terminal is connected to GND. Alternatively, a plurality of 5V lithium ion batteries that have been recently researched and developed may be connected in series. Further, a plurality of 2-3V lithium ion batteries using lithium titanate as the negative electrode active material may be connected in series. The number of lithium ion batteries constituting the sub battery 2 is determined by the specifications of the lithium ion battery and the output voltage of the alternator 12. Among these lithium ion batteries, a temperature sensor such as a thermistor is fixed to the surface of the battery can of one lithium ion battery arranged at the center by an adhesive.

Each lithium ion battery has an electrode group in which a positive electrode obtained by applying a positive electrode active material to an aluminum foil and a negative electrode obtained by applying a negative electrode active material to a copper foil are wound or laminated via a microporous separator. The electrode group has a cylindrical shape, a flat cylindrical shape, or a rectangular shape infiltrated with a nonaqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a mixed solvent such as ethylene carbonate and dimethyl carbonate. It is housed in a battery can of the type. A lithium transition metal composite oxide such as lithium manganese composite oxide can be used for the positive electrode active material of the lithium ion battery, and a carbon material or lithium titanate can be used for the negative electrode active material. In addition, the nominal voltage of each lithium ion battery of this embodiment is 3.8V, and the nominal voltage of the sub battery 2 is 15.2V.

<Selector 5>
As shown in FIG. 1, the power supply system 10 includes a selector 5 (switch means) that switches charging / discharging currents of the main battery 1 and the sub battery 2, and the other end and the other end of the selector 5 are respectively connected to the main battery 1. And connected to the positive terminal of the sub-battery 2. The selector 5 is composed of a plurality of switching elements (for example, power MOSFETs) capable of passing a large current. Here, the function of the selector 5 will be described. When the regenerative power supplied from the alternator 12 is received by the power storage device, the selector 5 serves as a switch connected to either the main battery 1 or the sub battery 2 from the alternator 12. 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. The selector 5 is in a state “0” where the alternator 12 / discharge load 14 is not connected to either the main battery 1 or the sub battery 2 (see FIG. 3A), and the alternator 12 / discharge load 14 is connected to the main battery 1. One of the state “1” (see FIG. 3B) to be connected and the state “2” (see FIG. 3C) in which the alternator 12 / discharge load 14 is connected to the sub-battery 2 is adopted (see FIG. 3C). (The main battery 1 and the sub battery 2 are not connected in parallel.)

  In a state “0” that is not connected to either the main battery 1 or the sub battery 2, a state in which no power is supplied to the discharge load 14 occurs for a moment. Examples of methods that can supply power even in the case of the state “0” that is not connected to either the main battery 1 or the sub battery 2 include the following (1) to (3). (1) A capacitor is arranged in parallel with the main battery 1. (2) A state “3” in which the main battery 1 and the sub battery 2 are simultaneously connected for a moment is provided. (3) A primary battery or a secondary battery other than the main battery 1 and the sub battery 2 is disposed.

When the method (1) is adopted, the voltages of the main battery 1 and the sub battery 2 are 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 + selector switching time) = X [μs] and the 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)
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 Is preferred.

<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, and the main battery controller 3 samples the voltage of the temperature sensor every predetermined time (for example, at intervals of 10 ms) The sampling result is stored 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 arranged between the main battery 1 and the selector 5 in order to detect a charging / discharging current flowing through the main battery 1, and the current sensor 7 is connected to the main battery controller 3. It is connected. 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 has the same configuration as the main battery controller 3 described above (the charge / discharge current flowing through the sub battery 2 is detected by the current sensor 8), but in addition to the detection of the total voltage of the sub battery 2 In addition, voltage detection other than that detected by the main battery controller 3 is also performed in that the voltage of each lithium ion battery is also detected in order to monitor overdischarge / overcharge. Further, the sub battery controller 4 may have a capacity adjustment circuit that adjusts the capacity of each lithium ion 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 lithium ion battery 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 (control means) that calculates battery states of the main battery 1 and the sub battery 2 and controls a current switching operation by the selector 5. The control unit 6 is configured as a microprocessor having a microcontroller (hereinafter referred to as a microcomputer), a communication IC, an I / O, an input port, and an output port. In FIG. 1, the role of the control unit 6 is clarified. Therefore, details are shown by function.

  That is, the microcomputer functions as a CPU for grasping (calculating) the battery state 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 a work area for the CPU, and temporarily stores various data. It is composed of a RAM for storing the data and an internal bus connecting them. The internal bus is connected to the external bus, and the external bus is connected to the above-described controllers 3 and 4 via input ports. Further, an output port for outputting a signal to the selector 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 microcomputer and the input port of the control unit 6 correspond to the state grasping unit 6A in FIG. 1, the microcomputer and the output port correspond to the selector control unit 6B, and the communication IC and I / O correspond to the communication unit 6C. 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 selector 5 and the output port are connected by a control line, and a resistor is inserted in the control line in order to prevent the microcomputer constituting the control unit 6 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 part of the control unit 6 will be described with reference to FIG. 1. The state grasping unit 6A temporarily stores the detection data output from the controllers 3 and 4 in the RAM, and the current battery of the main battery 1 and the sub battery 2 Calculate (estimate) the state and the like. 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), and from the vehicle control unit 16 to the vehicle. Receives notification of status information (IGN position information, alternator operation information). The vehicle control unit 16 notifies the communication unit 6C of the operation information of the alternator at almost the same timing as when the electromagnetic clutch described above is operated. The selector control unit 6B controls the selector 5 according to the operation information of the alternator notified from the vehicle control unit 16 and the battery status of the main battery 1 and the sub battery 2 calculated by the status grasping unit 6A.

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

(Operation)
Next, the operation of the power supply system 10 of the present embodiment will be described with a microcomputer 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 selector 5 is set to the above-described state “0”, the controllers 3 and 4 are stopped from detecting and outputting the temperature, voltage, current, etc. of the main battery 1 and sub battery 2, and the CPU itself is also connected to the main battery 1 and sub battery 2. The calculation of the battery state and the notification to the vehicle control unit 16 are stopped, and it is determined whether or not a predetermined time has elapsed since the notification that the IGN is positioned at the OFF position from the vehicle control unit 16. Only timekeeping 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 of the main battery 1 and the sub battery 2 (hereinafter abbreviated as SOC) from the OCV of the main battery 1 and the sub battery 2, and is stored in advance in the ROM as program data and expanded in the RAM. The SOC calculated by referring to the table or the mathematical formula is corrected to the SOC at the reference temperature (for example, 25 ° C.), and the reference SOC of 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 controller 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 controller 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 during 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, and is further positioned from the ON / ACC position to the START position. After that, it is 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 travel), the CPU 3 and 4 detect the voltage values of the main battery 1 and the sub battery 2 detected every predetermined time (each lithium ion battery constituting the sub battery 2). And the current values detected at predetermined intervals by the controllers 3 and 4 based on the reference SOC and the battery capacities (known) of the main battery 1 and the sub battery 2 described above are integrated. Then, the current SOCs of the main battery 1 and the sub battery 2 are 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 electromagnetic clutch is controlled so as not to operate the alternator 12 because there is a possibility of falling into an overcharge state. In the case of SOC (and / or lower limit voltage value) that promotes the deterioration of the main battery 1, the alternator can be used while the vehicle is running or before the vehicle is run without waiting for regenerative charging by the driver's brake operation or accelerator operation. 12 is operated to control the electromagnetic clutch so as to charge the main battery 1. This specific control content will be described later.

2. Regenerative charge / discharge control In short, the charge / discharge control of the present invention is characterized by charging the main battery 1 after charging the sub-battery 2 to the upper limit SOC when the regenerative power from the alternator 12 is received by the power storage device. When the selector 5 is controlled to discharge from the power storage device to the discharge load 14, the selector 5 is controlled to discharge from the main battery 1 after discharging until the sub battery 2 reaches a predetermined SOC. The details are as follows.

2-1. Control at the time of regenerative charge When the CPU receives (receives) regenerative start information indicating that the supply of regenerative power by the alternator 12 starts from the vehicle control unit 16, in principle, the sub battery 2 is used up to the upper limit SOC. The selector 5 is controlled so as to be charged (the selector 5 is allowed to select the state “2”). Since the alternator 12 has the voltage regulator as described above, the sub battery 2 is charged at a constant voltage up to the upper limit SOC. However, when the battery control unit 16 receives (receives) the regeneration end information indicating that the supply of the regenerative power by the alternator 12 is terminated before the sub battery 2 reaches the use upper limit SOC, the regenerative power Is not supplied, the charging to the sub-battery 2 is stopped at that time, and the selector 5 is controlled to immediately discharge from the sub-battery 2 to the discharge load 14 (the state in which the selector 5 is left in the state “2” selected) And).

  The vehicle control unit 16 controls the alternator 12 so as to output regenerative power when the brake is stepped on or when the accelerator is released (accelerator is off), and the control unit 6 (CPU). Is notified of the regeneration start information via the communication line 18, and the operation of the alternator 12 is stopped when the brake is released or when the acceleration of the vehicle becomes 0 as a result of the accelerator off, and the controller 6 (CPU) Is notified of 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 selector 5 is controlled so that the main battery 1 is charged up to the use upper limit SOC (the selector 5 is made to select the state “1”). Thereby, the main battery 1 is charged to the use upper limit SOC. 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 selector 5 is controlled to discharge from the battery 2 to the discharge load 14 (the selector 5 is made to select the state “2”).

  Further, when the main battery 1 is charged up to the use upper limit SOC, the selector 5 is controlled to stop charging the main battery 1 in order to avoid overcharging of the main battery 1 (the selector 5 is set to the state “0”). Let them choose.)

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). However, the selector 5 is controlled so as to discharge until the first SOC ≧ the lower limit of use of SOC) (the selector 5 selects the state “2”). In order to increase the utilization efficiency of regenerative power, the first SOC may be used as the lower limit SOC of the sub-battery 2 (an example of discharging to the lower limit SOC will be described below). However, when the regeneration start information is received from the vehicle control unit 16 before the sub battery 2 reaches the use lower limit SOC, regenerative electric power is supplied, and at that time, the discharge from the sub battery 2 to the discharge load 14 is performed. Is turned off and immediately controls the selector 5 to charge the sub-battery 2 with regenerative power (the state where the selector 5 is left in the state “2” is selected).

  The use upper limit SOC and the use lower limit SOC of the sub battery 2 vary greatly depending on the type, capacity, and the like of the sub battery 2, but in general, for the use upper limit SOC, an arbitrary value in the range of 90% to 98% is selected. As for the lower limit SOC, any value in the range of 0% to 40% can be selected. Here, the use lower limit SOC is preferably a state that is equal to or higher than the minimum voltage for operating the auxiliary equipment, and the voltage range is used at a voltage higher than the standard voltage 8V at which audio is cut off. It is preferable that the SOC corresponding to the lower limit voltage becomes the use lower limit SOC.

  Further, when sub battery 2 is discharged to the lower limit SOC, in principle, selector 5 is controlled to discharge main battery 1 to a predetermined second SOC (see FIG. 6B) (see FIG. 6B). Let the selector 5 select the state “1”). However, if the regeneration start information is received from the vehicle control unit 16 before the main battery 1 becomes the second SOC, charging to the main battery 1 is stopped at that time, and the discharge load 14 is immediately discharged from the sub battery 2. The selector 5 is controlled so as to be discharged (the selector 5 selects the state “2”).

  This second SOC can be set to an SOC for preventing deterioration of the main battery 1 (lead storage battery). In the lead storage battery, since it is generally considered that the deterioration is accelerated when the SOC falls below 70%, the second SOC can be selected from any value within the range of SOC 70 to 90%, for example. In the following description, it is assumed that the second SOC is set to 70%. In the present embodiment, the second 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, in order to store as much regenerative power as possible in the main battery 1, it is preferable to charge the main battery 1 to the upper limit SOC. On the other hand, when the main battery 1 is discharged to the second 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 second SOC to the upper limit SOC, but a predetermined third SOC (see FIG. 6B, (second SOC) <(third 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. However, in order to prevent the deterioration of the main battery 1, the value is kept larger than the second SOC. Need to be. The above-described third SOC is, for example, (third SOC) = (second SOC) + {(SOC for supplying power to the discharge load 14 at the time of idling stop + SOC for engine restart after idling stop) )}.

  When the main battery 1 is discharged to the second SOC, the CPU charges the main battery 1 to the third SOC by cooperative control with the vehicle control unit 16 in order to prevent deterioration of the main battery 1. The selector 5 is controlled (the selector 5 is made to select the state “1”).

  Next, the above-described charge / discharge control will be further described with reference to a flowchart with the CPU as a 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, standby is performed until regeneration start information (step 102) or 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), at step 104, the selector 5 is made to select the state “2”. Thereby, the sub battery 2 is charged at a constant voltage with regenerative power. Next, in step 106, 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 terminated). If the determination is negative, the next step 108 is determined. It is determined whether the sub battery 2 has reached the upper limit SOC. If the determination in step 108 is negative, the process returns to step 106. If the determination is affirmative, the selector 5 is made to select the state “1” in the next step 110. Thereby, the main battery 1 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 main battery 1 is terminated). If the determination is negative, the next step 114 is performed. It is determined whether or not the main battery 1 has reached the use upper limit SOC. If the determination in step 114 is negative, the process returns to step 112. If the determination is affirmative, the selector 5 is caused to select the state “0” in the next step 116, 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 at step 202 (when regeneration end information is received), the selector 5 is made to select the state “2” at step 204. Thereby, the electric power of the sub battery 2 is supplied to the discharge load 14. Next, in step 206, it is determined whether or not regeneration start information has been received. If the determination is affirmative, the process returns to step 104 (discharging from the sub battery 2 to the discharge load 14 is terminated), and if the determination is negative, In the next step 208, it is determined whether or not the sub battery 2 has reached the use lower limit SOC. If the determination in step 208 is negative, the process returns to step 206. If the determination is affirmative, the selector 5 is caused to select the state “1” 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 (discharging from the main battery 1 to the discharge load 14 is terminated), and if the determination is negative, In the next step 214, it is determined whether the main battery 1 has reached the second SOC. 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 the sleep state upon receiving notification from the vehicle control unit 16 that the IGN is positioned at the OFF position. At that time, the selector 5 is in the state “0”. Returned to

  As shown in FIG. 5, in the main battery charging process subroutine, in step 232, the vehicle control unit 16 is notified that the main battery 1 has reached the second SOC. Receiving this notification, the vehicle control unit 16 controls the alternator start information indicating that the alternator 12 is started by starting the alternator 12 by operating the electromagnetic clutch described above and transmitting the rotational force of the engine (not shown) to the alternator 12. Notify 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 second SOC described above. In order to prevent the SOC of the main battery 1 from becoming smaller than the second SOC, the vehicle control unit 16 informs the vehicle controller 16 that the main battery 1 reaches the second SOC before the main battery 1 reaches the second SOC. What is necessary is just to inform.

  When an affirmative determination is made in step 234 (when the alternator start information is received from the vehicle control unit 16), the CPU causes the selector 5 to select the state “1” in the next step 236. As a result, the main battery 1 is charged, but this charging is not based on regenerative power at the time of braking or the like, but is a charging method similar to that of a conventional gasoline vehicle or the like.

  Next, in step 238, the process waits until the main battery 1 is charged to the third SOC. When the main battery 1 is charged up to the third SOC, in the next step 240, the vehicle control unit 16 is notified that the main battery 1 has been charged up to the third 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 the above description, in order to explain the control contents in an easy-to-understand manner, an example in which the main battery 1 has reached the second and third SOCs in steps 232 and 240 has been shown. As described above, since 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, it is not always necessary to perform such notification. For example, the vehicle control unit 16 monitors the SOC of the main battery 1 every predetermined time and controls the alternator 12 to start when the main battery 1 reaches the second SOC or immediately before the main battery 1 reaches the second SOC. You may make it alert | report start information.

  Further, for the charging of the main battery 1, the same processing as 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 or not the main battery 1 has reached the second SOC, whereas before the vehicle travels, since the CPU has just awakened, the main battery 1 is self-discharged or the like. It is different in that it is determined whether or not the second SOC or lower is reached.

Furthermore, in the above description, the SOC has been mainly described in order to briefly explain the charge / discharge control. However, in the present embodiment, in addition to the upper limit SOC and the lower limit SOC of the sub battery 2, the upper limit of the sub battery 2 is used. When the voltage V _U , the use lower limit voltage V _L , the use upper limit voltage and the use lower limit voltage of each lithium ion battery constituting the sub battery 2 are set in advance, and the sub battery 2 reaches the use upper limit voltage V _U In this case, the charging of the sub battery 2 by regenerative power is stopped and the main battery 1 is charged. When the sub battery 2 reaches the lower limit voltage _VL , the discharge from the sub battery 2 to the discharge load 14 is stopped. Control of discharging from the battery 1 to the discharge load 14 is also performed. The main battery 1 also has a use upper limit voltage and a use lower limit voltage set in the same manner as the sub battery 2, and, similarly to the sub battery 2, according to the use upper limit voltage and the use lower limit voltage, and further, the second SOC. The charging / discharging control of the main battery 1 is also performed according to the voltage corresponding to.

3. Abnormality processing The CPU monitors whether or not the voltage value of each lithium ion battery constituting the sub battery 2 is within a predetermined range and the temperature of the sub battery 2. When the voltage value of each lithium ion battery or the temperature of the sub-battery 2 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 selector 5 to select the 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.

(Effects etc.)
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 the control unit 6 accepts the regenerative power from the alternator 12 by the power storage device, the selector 5 is charged so as to charge the main battery 1 after charging the sub battery 2 to the upper limit SOC. And the selector 5 is controlled to discharge from the main battery 1 after discharging until the sub battery 2 reaches the first SOC. For this reason, according to the power supply system 10, since the regenerative electric power stored in the sub battery 2 can be discharged to the discharge load 14 without waiting for the charging / discharging pause as in the power supply system of Patent Document 1, the entire power storage device Can improve the efficiency of use. Therefore, the alternator regenerative vehicle 20 equipped with the power supply system 10 can improve the fuel efficiency improvement rate.

  Moreover, in the power supply system 10 of this embodiment, when the control part 6 discharges from the electrical storage device to the discharge load 14, it discharges from the main battery 1 after discharging until the sub battery 2 becomes the use lower limit SOC. The selector 5 is controlled. Since the electric power in the range from the use upper limit SOC stored in the sub-battery 2 to the use lower limit SOC can be discharged to the discharge load 14, high utilization efficiency can be ensured for the regenerative power generated by the alternator 12.

  Further, in the power supply system 10 of the present 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, and the main battery 1 is the second SOC (this embodiment). Since the selector 5 is controlled so as to charge the main battery 1 when discharged to 70%), deterioration of the main battery 1 can be prevented. At this time, the control unit 6 controls the selector 5 so as to charge the main battery 1 to the third SOC lower than the upper limit SOC of the main battery 1, so that the fuel consumption can be improved as described above.

  In the present embodiment, an example is shown in which the current SOC of the main battery 1 and the sub battery 2 is estimated by calculating the reference SOC from the OCV and integrating the charge / discharge current with respect to the reference SOC. It is not limited to this, A well-known SOC estimation means can be used. For example, when the sub battery 2 is a lead storage battery, the specific gravity of the electrolyte may be measured and the SOC may be estimated from the specific gravity.

  In the present embodiment, the main battery controller 3, the sub battery controller 4, and the control unit 6 have been described so as to make it easier to grasp the configuration of the power supply system 10, but these may be configured integrally. . Furthermore, in this 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 selector control unit 6B and the communication unit 6C.

  Furthermore, in this embodiment, although the example which performs engine starting with the main battery 1 was shown, this invention is not restrict | limited to this, You may make it perform engine starting with the sub battery 2. FIG. In the present embodiment, the operation power of the controllers 3 and 4, the control unit 6, and the vehicle control unit 16 is supplied from the main battery 1, but may be supplied from the sub battery 2, In addition, the main battery 1 and the sub battery 2 may supply the operating power to the controllers 3 and 4, the control unit 6, and the vehicle control unit 16 in cooperation or sharing. 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.

  Further, in the present embodiment, an example is shown in which the OCV of the main battery 1 and the sub battery 2 is measured after 6 hours of vehicle parking in accordance with the lead storage battery constituting the main battery 1, but the present invention is limited to this. It is not something. When LIB or LIC is used for the sub-battery 2, the polarization elimination of the sub-battery 2 is shorter than 6 hours. Therefore, the OCV may be measured for the sub-battery 2 at a time different from that of the main battery 1. Good. In such an aspect, since the accuracy of grasping the reference SOC of the sub battery 2 can be increased, it becomes a problem to be examined as the battery capacity of the sub battery 2 increases and the power supply to the discharge load 14 increases. In the present embodiment, the CPU of the control unit 6 counts 6 hours. However, the vehicle control unit 16 counts time, and the control unit 6 and the controllers 3 and 4 are awakened (from the sleep state). You may make it make it.

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

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

  Since the present invention provides a power supply system capable of improving the fuel efficiency improvement rate and a vehicle equipped with the power supply system, it contributes to the manufacture and sale of the power supply system and the vehicle, and thus has industrial applicability.

1 Main battery (first power storage device)
2 Sub battery (second power storage device)
5 Selector (switch means)
6 Control unit (control means, SOC estimation means)
10 Power System 12 Alternator 14 Discharge Load 20 Alternator Regenerative Vehicle (Vehicle, Automobile)

Claims (5)

In a power supply system equipped with a power storage device mounted on a vehicle and capable of receiving regenerative power supplied from an alternator and capable of discharging to a discharge load,
A first power storage device for starting the engine ;
A second power storage device;
Switch means for switching charge / discharge currents of the first and second power storage devices;
SOC estimation means for estimating a state of charge (SOC) of the first and second power storage devices;
Control means for controlling a current switching operation by the switch means based on the SOC of the second power storage device estimated by the SOC estimation means;
With
When the regenerative power is received by the power storage device, the control unit charges the second power storage device to a use upper limit SOC, and then charges the first power storage device and discharges the power from the power storage device to the discharge load. In this case, after the second power storage device is discharged until reaching a first predetermined SOC, the first power storage device is discharged , and the first power storage device has a predetermined SOC of 70% or more. And controlling the switch means to charge the first power storage device to a predetermined third SOC lower than the upper limit SOC of the first power storage device when discharged to the second SOC. A power supply system characterized by that.   The control means controls the switch means to discharge from the first power storage device after discharging until the second power storage device reaches a lower limit of use SOC when discharging from the power storage device to the discharge load. The power supply system according to claim 1, wherein: Retrieving start information indicating that the supply of regenerative power by the alternator starts from the vehicle side and acquisition end information indicating that the supply of regenerative power by the alternator ends, and
The control means controls the switch means to start charging the second power storage device with the regenerative power when the acquisition means acquires the regeneration start information, and the acquisition means Controlling the switch means to stop charging the second or first power storage device by the regenerative power and to discharge the second power storage device to the discharge load when the end information is acquired. the power supply system according to claim 1 or claim 2, characterized. The first power storage device is one selected from the group consisting of a lead storage battery, a nickel metal hydride battery, a nickel zinc battery, and a lithium ion battery, and the second power storage device is a lead storage battery, a nickel metal hydride battery, nickel The power supply system according to any one of claims 1 to 3 , wherein the power supply system is one selected from the group consisting of a zinc battery, a lithium ion battery, a lithium ion capacitor, and an electric double layer capacitor. . An automobile provided with the power supply system according to any one of claims 1 to 4 .

Images