JP6337596B2 - 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 during braking and discharging to a discharge load, and the power supply system. It relates to automobiles.

  Conventionally, in mobile bodies such as automobiles (vehicles), as seen in ordinary gasoline cars, electric power supplied from an alternator is charged to an electricity storage device such as a lead-acid battery while 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 circumstances, an automobile (manufacturing) company is developing an alternator regenerative vehicle that charges an electricity storage device with regenerative power supplied from an alternator during braking. 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 electricity storage device is charged with regenerative power supplied during braking from an alternator, which was consumed by heat from a regular gasoline vehicle. Reduces gasoline consumption by the engine to activate the alternator (by stopping charging the device). All power supply to the auxiliary machine when 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 to accept regenerative power supplied from the alternator during braking. 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-described problem, a first aspect of the present invention is a power supply system that includes an electricity storage device that is mounted on a vehicle, can receive regenerative power supplied from an alternator during braking, and can discharge to a discharge load. A first power storage device; a second power storage device composed of a battery or a capacitor; switch means for switching charge / discharge currents of the first and second power storage devices; and a current switching operation by the switch means. Control means, and when the regenerative power is received by the power storage device, the control means first charges the second power storage device at a constant voltage for a preset first predetermined time , and then the second power storage device . when the first predetermined time has elapsed, the first power storage device to control said switch means to a constant voltage charging, from the storage device Controlling the switch means to discharge from the second power storage device to the discharge load first and then from the first power storage device to the discharge load when discharging to the discharge load. Features.

In the first aspect, in order to increase the utilization efficiency of the power storage device, the vehicle includes an acquisition unit that acquires braking start information indicating that the brake is stepped on from the vehicle side and braking end information indicating that the brake is released, The control means controls the switch means so as to immediately discharge the second power storage device to the discharge load when the acquisition means acquires the braking end information after the regenerative power is received by the second or first power storage device. It is preferable to do. 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. Alternatively, one selected from the group consisting of a lithium ion battery, a lithium ion capacitor, and an electric double layer capacitor may be used.

At this time, in order to prevent overcharging of the second power storage device, provided with a SOC estimating means for estimating the state of charge of the second power storage device (SOC), the control means, second power storage device by regenerative power The time until the use upper limit SOC set in advance is calculated based on the latest SOC of the second power storage device estimated by the SOC estimation means before or during charging to the first predetermined time. If the time is longer than the set time, the charging of the second power storage device by the regenerative power may be stopped at the calculated time, and the switch unit may be controlled to charge the first power storage device. Further, control means, when the acquisition unit has acquired the braking start information, controls the switch means to initiate a constant-voltage charging to the second power storage device by regenerative power, the acquisition means the braking end information When acquired, the switch means may be controlled so as to stop charging the second or first power storage device with regenerative power.

  Furthermore, the control means discharges the second power storage device to the discharge load for a preset second predetermined time when discharging from the power storage device to the discharge load, and when the second predetermined time has elapsed, The switch means may be controlled to discharge from one power storage device to a discharge load. At this time, in order to prevent overdischarge of the second power storage device, SOC estimation means for estimating the state of charge (SOC) of the second power storage device is provided, and the control means is connected to the discharge load from the second power storage device. The time until the use lower limit SOC set in advance is calculated based on the latest SOC of the second power storage device estimated by the SOC estimation means before or during the discharge of the second, and the second predetermined time is calculated. If the time is longer than the predetermined time, the discharge from the second power storage device to the discharge load may be stopped at the calculated time, and the switch means may be controlled to discharge from the first power storage device to the discharge load.

  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 means accepts the regenerative power by the power storage device, the control unit first charges the second power storage device at a constant voltage for a preset first predetermined time , and then the first predetermined time elapses. In this case, the switch means is controlled to charge the first power storage device at a constant voltage , and when discharging from the power storage device to the discharge load, the first power storage device is first discharged to the discharge load, and then the first Since the switch means is controlled so as to discharge from the power storage device to the discharge load, the power stored in the second power storage device can be discharged to the discharge load without waiting for the charging / discharging pause. It is possible to obtain an effect that the efficiency can be improved and the fuel efficiency improvement rate of the vehicle can be improved.

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 the state 0, (B) shows the state 1, (C) shows the state 2. It is explanatory drawing which shows typically SOC of the sub battery by regenerative electric power reception, (A) is SOC of the sub battery in the regular charge in this embodiment, (B) is in charge termination by brake release in this embodiment. The SOC of the sub battery, (C) the SOC of the sub battery when charging is terminated by the upper limit SOC in this embodiment, and (D) shows the SOC of the sub battery in another embodiment. It is explanatory drawing which shows typically SOC of the sub battery by the discharge to discharge load, (A) is SOC of the sub battery in the steady discharge in this embodiment, (B) is by use minimum SOC in this embodiment. The SOC of the sub battery in the discharge termination, (C) indicates the SOC of the sub battery in another embodiment.

  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 having an ISS function, including a power storage device that can accept regenerative power supplied from an alternator during braking and 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, and other vehicle states are grasped, and travel 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 brake operation information). The brake operation information includes braking start information indicating that the brake (pedal) has been depressed and braking end information indicating that the brake has been released.

<Alternator 12>
The alternator regenerative vehicle 20 is provided with an alternator 12 that converts the rotational force of the engine (not shown) mainly into (regenerative) power during braking. 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 during braking.

  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 during braking 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 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 a 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 during braking, the selector 5 serves as a switch connected to either the main battery 1 or the sub battery 2. At the same time, 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. The state “1” (see FIG. 3B) to be connected and the state “2” (see FIG. 3C) to which the alternator 12 / discharge load 14 is connected to the sub-battery 2 are taken.

  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 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.

  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 microcomputer (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, etc. 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 state information (IGN position information, brake operation information). The vehicle control unit 16 notifies the communication unit 6C of brake operation information at substantially the same timing as when the electromagnetic clutch described above is operated. The selector control unit 6B controls the selector 5 according to the brake operation information notified from the vehicle control unit 16 and the battery states of the main battery 1 and the sub battery 2 calculated by the state grasping unit 6A.

  In the present embodiment, the controllers 3 and 4, the 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 / discharging>
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 (the alternator 12 is generated to charge the power storage device). That is, for example, when the main battery 1 is close to the use upper limit voltage value, there is a possibility that the main battery 1 falls into an overcharge state, so that the electromagnetic clutch is controlled so that the alternator 12 is not operated. If it is close to the lower limit voltage value, the engine may not be restarted after idling stop. Therefore, the alternator 12 is operated during or before traveling the vehicle without waiting for regenerative charging by the driver's brake operation. The electromagnetic clutch is controlled so as to charge the battery 1.

2. Control during Regenerative Charging / Discharging One of the features of the present invention is that when the regenerative power from the alternator 12 is received by the power storage device, the sub battery 2 is charged first, and then the selector 5 is charged. When controlling and discharging from the electricity storage device to the discharge load 14, the selector 5 is controlled so that the sub battery 2 is first discharged to the discharge load 14 and then the main battery 1 is discharged to the discharge load 14. Below, control at the time of regenerative charging / discharging by CPU is explained in full detail.

2-1. Control during regenerative charging When receiving the brake start information indicating that the brake has been depressed from the vehicle control unit 16, the CPU, as a general rule, holds the sub-battery 2 for a preset first predetermined time T1. The selector 5 is controlled so as to be charged (see FIG. 4A) (the selector 5 is made to select the state “2”). Since the alternator 12 has a voltage regulator as described above, the sub battery 2 is charged at a constant voltage. However, (1) the brake is released from the vehicle control unit 16 before the first predetermined time T1 elapses after the CPU receives the brake start information indicating that the brake is depressed from the vehicle control unit 16. When the notification of the braking end information indicating that it has been received is received (see FIG. 4B), and (2) the sub battery 2 is charged at a constant voltage for the first predetermined time T1, the sub battery 2 There are two exceptions when charging exceeds the preset upper limit SOC and the sub-battery 2 may fall into an overcharged state (see FIG. 4C).

  For this reason, when the CPU receives the brake start information notification from the vehicle control unit 16, as shown in FIG. 4C, the charging time T1 '' from the estimated current SOC (estimated SOC) to the use upper limit SOC. Is calculated, and it is determined whether or not the first predetermined time T1 is longer than the calculated charging time T1 ″. For such calculation of the charging time T <b> 1 ″, for example, a table or a mathematical expression that represents the relationship between the SOC and the time to the upper limit of use SOC that is stored in advance in the ROM and expanded in the RAM is used. In the present embodiment, the CPU calculates the charging time T1 ″ when receiving the brake start information notification from the vehicle control unit 16 (during regenerative charging of the sub battery 2), but calculates the current SOC. At the same time, the charging time T1 ″ may be calculated in advance (calculated before regenerative charging of the sub battery 2).

  When the charging time T1 ″ calculated by the first predetermined time T1 is shorter (refer to FIG. 4A when the determination is negative), the state “2” is selected for the first predetermined time T1. The selector 5 is controlled as described above, and when the first predetermined time T1 has elapsed, the selector 5 is controlled to select the state “1”. On the other hand, when the first predetermined time T1 is longer than the calculated charging time T1 ″ (when the determination is affirmative, refer to FIG. 4C), the state “2” is changed during the calculated charging time T1 ″. The selector 5 is controlled to select, and when the calculated charging time T1 ″ has elapsed, the selector 5 is controlled to select the state “1”. However, during the first predetermined time T1 or the calculated charging time T1 ″ (T1 ″ <T1) (during charging of the sub-battery 2 with regenerative power), the CPU receives braking end information from the vehicle control unit 16. When the notification is received, the regenerative charging to the sub battery 2 is terminated at that time. FIG. 4B shows that the process is terminated when T1 'elapses from the start of charging. In this case, regenerative charging to the main battery 1 is not performed. In addition, CPU will perform control which stops the charge to the main battery 1, if the notification of braking completion information is received from the vehicle control part 16 in the main battery 1 by regenerative electric power.

2-2. Control at the time of regenerative discharge After receiving regenerative power from the alternator 12 by the sub battery 2 or the main battery 1, the CPU immediately receives the brake end information notification from the vehicle control unit 16 to the discharge load 14 from the sub battery 2. Then, the selector 5 is controlled so as to discharge for a preset second predetermined time T2 (see FIG. 5A). However, if the sub-battery 2 discharges to the discharge load 14 during the second predetermined time T2, the sub-battery 2 may be over-discharged due to discharge exceeding the preset lower limit SOC of the sub-battery 2. There are exceptions to the case (see FIG. 5B).

  For this reason, when receiving the notification of the braking end information from the vehicle control unit 16, the CPU calculates the discharge time T2 ′ from the estimated current SOC (estimated SOC) to the use lower limit SOC as shown in FIG. It is calculated and it is determined whether or not the second predetermined time T2 is longer than the calculated discharge time T2 ′. For the calculation of the discharge time T <b> 2 ′, a table or a mathematical expression representing the relationship between the SOC and the time until the use lower limit SOC is used. In the present embodiment, the CPU calculates the discharge time T2 ′ when receiving the brake end information notification from the vehicle control unit 16 (during discharging of the sub battery 2), but when calculating the current SOC. In addition, the discharge time T2 ′ may be calculated in advance (calculated before the sub battery 2 is discharged).

  When the discharge time T2 ′ calculated by the second predetermined time T2 is shorter (refer to FIG. 5A when the determination is negative), the CPU changes the state “2” for the second predetermined time T2. The selector 5 is controlled to select, and when the second predetermined time T2 has elapsed, the selector 5 is controlled to select the state “1”. On the other hand, when the second predetermined time T2 is longer than the calculated discharge time T2 ′ (when the determination is affirmative, see FIG. 5B), the state “2” is selected during the calculated discharge time T2 ′. The selector 5 is controlled as described above, and when the calculated discharge time T2 ′ has elapsed, the selector 5 is controlled to select the state “1”. When charging of the sub battery 2 is stopped during charging of the sub battery 2 with regenerative power according to the braking end information from the vehicle control unit 16 (see FIG. 4B), the sub battery 2 immediately discharges from the discharge load. 14, the selector 5 remains in the state of selecting the state “2”.

  The use upper limit SOC and the use lower limit SOC described above vary greatly depending on the type, capacity, and the like of the sub-battery 2. In general, for example, an arbitrary value in the range of 90% to 98% can be selected for the use upper limit SOC. The lower limit SOC can be selected from any value within the range of 5% to 40%. 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. The SOC corresponding to the lower limit voltage is preferably the lower limit SOC.

In the above description, the SOC of the sub battery 2 has been mainly described in order to briefly describe the control during regenerative charging / discharging. However, in the present embodiment, in addition to the upper limit SOC and lower limit SOC of the sub battery 2, The upper limit voltage V _U and the lower limit voltage V _{L for} use of the sub battery 2 and the upper limit voltage and the lower limit voltage for use of each lithium ion battery constituting the sub battery 2 are also set in advance. when it reaches the voltage V _U, as in the case shown in FIG. 4 (C), the charging of the sub-battery 2 by regenerative power to charge the truncation main battery 1, the sub-battery 2 is used lower limit voltage V _L When reaching the value, the control is performed to stop the discharge from the sub battery 2 to the discharge load 14 and to discharge from the main battery 1 to the discharge load 14 as in the case shown in FIG. In the present embodiment, similarly to the sub battery 1, the main battery 1 has a use upper limit SOC, a use lower limit SOC, a use upper limit voltage, and a use lower limit voltage.

3. Other processing 3-1. Relationship with ISS Since the brake is stepped on at the time of idling stop in the μHEV, the same control as in the above case 2 is performed as in the ISS vehicle. Further, when the vehicle is stopped at the time of idling stop, the sub-battery 2 or the main battery 1 is discharged to the discharge load 14. When the engine is restarted, power is supplied from the main battery 1 to the starter as in the case of starting the engine, and the engine is started.

  Since power is supplied from the main battery 1 to the starter when the engine is restarted after idling is stopped, the main battery 1 needs to be maintained at a value equal to or higher than the above-described use lower limit SOC and use lower limit voltage. This is the same even before the vehicle travels. Since the vehicle control unit 16 receives a notification of the current SOC estimated value and voltage value of the main battery 1 from the control unit 6 every predetermined time, the main battery 1 uses the lower limit SOC, lower limit voltage value, or When discharged to a value close to that, the engine is started and the main battery 1 is charged as described above. At that time, the CPU receives a notification from the vehicle control unit 16 and causes the selector 5 to select the state “1” according to the notification.

3-2. 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 control unit 6 controls the selector 5 so that the sub battery 2 is charged first and then the main battery 1 is charged. Then, when discharging from the electricity storage device to the discharge load 14, the selector 5 is controlled so that the sub battery 2 is first discharged to the discharge load 14 and then the main battery 1 is discharged to the discharge load 14. 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.

  Further, in the power supply system 10 of the present embodiment, the control unit 6 receives the regenerative power from the alternator 12 by the sub battery 2 or the main battery 1 and immediately discharges from the sub battery 2 to the discharge load 14 so that the selector 5 To control. Since the regenerative power stored in the sub-battery 2 can be immediately discharged to the discharge load 14, high utilization efficiency can be ensured.

  In the power supply system 10 of the present embodiment, the charging time T1 (see FIG. 4 (A)) and the discharging time T2 (see FIG. 5 (A)) are set as preset fixed times, and the charging time until the upper limit SOC is used. Since only T1 '' (see FIG. 4C) and discharge time T2 ′ (see FIG. 5B) to the lower limit of use SOC are calculated and compared with charge time T1 and discharge time T2, the calculation of control unit 6 Load (power consumption) can be reduced. The voltage value output from the sub battery controller 4 is monitored, and when the voltage value of the sub battery 2 reaches a voltage value corresponding to the upper limit SOC and the lower limit SOC, the sub battery 2 is charged with regenerative power. If the control is terminated, the calculation of the charging time T1 ″ and the discharging time T2 ′ and the comparison with the charging time T1 and the discharging time T2 are not required, so that the calculation load of the control unit 6 can be further reduced.

  In the present embodiment, the example in which the charging time T1 and the discharging time T2 are set as preset fixed times has been described, but the present invention is not limited to this. For example, instead of the charging time T1 shown in FIG. 4A, as shown in FIG. 4D, the charging time T ′ from the estimated current SOC (estimated SOC) to the use upper limit SOC is calculated each time. Instead of the discharge time T2 shown in FIG. 5 (A), as shown in FIG. 5 (C), the discharge time T ″ from the estimated current SOC (estimated SOC) to the use lower limit SOC is calculated each time. You may do it. Such charging time T ′ and discharging time T ″ are considered variable times.

  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 2. 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, the accuracy of grasping the reference SOC of the sub-battery 2 can be increased, and this becomes an issue 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 action | operation information of a brake via the vehicle control part 16 in this embodiment, this invention is not restricted to this, For example, from the brake control part which controls a brake The brake operation information may be acquired directly.

  Further, in the present embodiment, the 14V power supply system 10 is exemplified, but 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.

  In this embodiment, the case where the charging time T1 (see FIG. 4A) and the discharging time T2 (see FIG. 5A) are set to different values has been described. However, the charging time T1 = discharging. Time T2 may be set. Therefore, in the power supply system including the power storage device mounted on the vehicle and capable of receiving the regenerative power supplied from the alternator during braking and discharging to the discharge load, the first power storage device, A second power storage device composed of a battery or a capacitor, switch means for switching charge / discharge currents of the first and second power storage devices, and control means for controlling a current switching operation by the switch means, When the regenerative power is received by the power storage device, the control means charges the second power storage device at a constant voltage for a first predetermined time, and when the first predetermined time has elapsed, When controlling the switch means to charge the first power storage device at a constant voltage and discharging from the power storage device to the discharge load, The second power storage device is discharged to the discharge load for a second predetermined time set in advance, and when the second predetermined time has elapsed, the first power storage device is discharged to the discharge load. The power supply system is characterized in that the switch means is controlled, and the first predetermined time and the second predetermined time are set to an equal fixed time value. "

  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)
T1 charging time (first predetermined time)
T2 discharge time (second predetermined time)

Claims (8)

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 during braking and discharging to a discharge load,
A first power storage device;
A second power storage device composed of a battery or a capacitor;
Switch means for switching charge / discharge currents of the first and second power storage devices;
Control means for controlling the current switching operation by the switch means;
With
The control means includes
When the regenerative power is received by the power storage device, the second power storage device is first charged at a constant voltage for a preset first predetermined time, and then when the first predetermined time has elapsed, Controlling the switch means to charge one power storage device at a constant voltage,
When discharging from the power storage device to the discharge load, the switch means is controlled to discharge first from the second power storage device to the discharge load and then from the first power storage device to the discharge load. To
A power supply system characterized by that. Obtaining means for obtaining braking start information indicating that the brake is depressed from the vehicle side and braking end information indicating that the brake is released;
After the regenerative power is received by the second or first power storage device, the control means immediately discharges from the second power storage device to the discharge load when the acquisition means acquires the braking end information. The power supply system according to claim 1, wherein the switch unit is controlled to do so. SOC estimation means for estimating a state of charge (SOC) of the second power storage device,
The control means is configured to use a preset upper limit based on the most recent SOC of the second power storage device estimated by the SOC estimation means before or during charging of the second power storage device with the regenerative power. When the time until the SOC is calculated and the first predetermined time is longer than the calculated time, charging the second power storage device by the regenerative power is terminated at the calculated time, power system according to 請 Motomeko 2 shall be the controls said switching means so as to charge the first power storage device.   The control means controls the switch means to start constant voltage charging to the second power storage device by the regenerative power when the acquisition means acquires the braking start information, and the acquisition means 4. The switch unit according to claim 2, wherein when the braking end information is acquired, the switch unit is controlled to stop charging the second to first power storage devices by the regenerative power. 5. Power system.   The control means discharges the second power storage device to the discharge load for a preset second predetermined time when discharging from the power storage device to the discharge load, and the second predetermined time has elapsed. 3. The power supply system according to claim 1, wherein the switch unit is controlled to discharge from the first power storage device to the discharge load. SOC estimation means for estimating a state of charge (SOC) of the second power storage device,
The control means is a use lower limit preset based on the most recent SOC of the second power storage device estimated by the SOC estimation means before or during discharge from the second power storage device to the discharge load. When calculating the time until the SOC is reached and the second predetermined time is longer than the calculated time, the discharge from the second power storage device to the discharge load is interrupted at the calculated time, The power supply system according to claim 5, wherein the switch unit is controlled to discharge from the first power storage device 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, nickel The power supply system according to any one of claims 1 to 6, 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 7.

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