JP2011176958A - In-vehicle power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-vehicle power supply equipped with a high performance storage battery (the second storage battery) to prevent deterioration of a lead storage battery and reduce a cost, while eliminating a DC-DC converter which has been conventionally indispensable, to sufficiently reducing cost, and suppressing overdischarge or overcharge of a lead storage battery. <P>SOLUTION: The in-vehicle power supply including the lead storage battery and the lithium storage battery connected in parallel includes: a MOS-FET (first switching means and rectifying means) electrically connecting or disconnecting a generator to/from the lithium storage battery, and a relay (second switching means) which is electrically connected between the MOS-FET and the lithium storage battery to supply or cut off power to the lithium storage battery. An operation state of both the switching means and setting voltage Vreg by a regulator are controlled so that SOC (Pb) and SOC (Li) are within proper ranges W1 and W2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-vehicle power supply device applied to a vehicle including a generator capable of regenerative power generation by regenerative energy.

  In general, a vehicle using an internal combustion engine as a driving source is equipped with a lead storage battery for supplying electric power to various electric loads such as a starter motor. A lead storage battery is less expensive than a high output / high energy density storage battery (high performance storage battery) such as a nickel storage battery or a lithium storage battery, but has low durability against frequent charging / discharging (cumulative charging / discharging amount). Particularly in a vehicle having an idle stop function, the lead storage battery is frequently discharged, and there is a concern about early deterioration. Further, in a vehicle in which the alternator is generated by the regenerative energy of the vehicle and charged, the lead storage battery is frequently charged, so there is a concern about early deterioration. In response to these concerns, simply replacing the lead-acid battery with the above-described high-performance battery results in a significant cost increase.

  Therefore, Patent Documents 1 to 5 propose that both a high-performance storage battery (second storage battery) having high durability against frequent charge and discharge and an inexpensive lead storage battery are connected in parallel. That is, power supply and charging (especially regenerative charging) to the electric load during idle stop are performed preferentially by the high-performance storage battery, thereby reducing the deterioration of the lead storage battery. On the other hand, when powering a vehicle (dark current supply) required for a long time, such as when parking a vehicle, an inexpensive lead-acid battery is used to reduce the capacity of the high-performance battery and reduce costs. Plan.

JP 2007-46508 A JP 2007-131134 A JP 2008-29058 A JP 2008-155814 A JP 2009-126395 A

  By the way, if the storage battery is overcharged or overdischarged, there is a concern about early deterioration. Therefore, it is desirable to use the storage battery so that the SOC (State of charge: the ratio of the actual charge amount with respect to the charge amount at the time of full charge) is in a range (appropriate range) that does not cause overcharge / discharge. And although the open circuit voltage of a storage battery becomes a different value according to SOC, the open circuit voltage (for example, 12.7V-12.8V) in the appropriate range of a lead storage battery and the open circuit voltage in the appropriate range of a high performance storage battery do not correspond. It is normal.

  Then, since both the storage batteries are connected in parallel, at the time of discharging, current flows from the storage battery on the higher side of the terminal voltage Vd (see Equation 1 below) to the storage battery on the lower side, There is concern about overdischarge. When the discharge current is Id, the internal resistance of the storage battery is R, and the open voltage of the storage battery is V0, the terminal voltage Vd of the storage battery at the time of discharge is expressed by Equation 1 such as “Vd = V0−Id × R”.

  Therefore, in the power supply devices described in Patent Documents 1 to 5, a DCDC converter is provided between both storage batteries, and the terminal voltage of the storage battery (mainly a high performance storage battery) on the high voltage side is adjusted by the DCDC converter. In this case, current is prevented from flowing from the high-performance storage battery to the storage battery (mainly lead storage battery) on the low voltage side, thereby avoiding overcharging of the lead storage battery.

  However, since the DCDC converter is expensive, the above-described power supply apparatus in which it is essential to provide the DCDC converter cannot sufficiently reduce the cost. In response to this problem, the present applicant has applied for the following invention (prior invention) in Japanese Patent Application No. 2009-223947.

  That is, in a vehicle-mounted power supply device in which a lead storage battery and a high performance storage battery (second storage battery) electrically connected to an alternator are electrically connected in parallel, a MOS-FET (opening / closing means) is provided between the alternator and the second storage battery. The MOS-FET inevitably has a parasitic diode (rectifying means) due to its internal structure, and the MOS-FET is provided so that the direction of current flow from the lead storage battery to the second storage battery is the forward direction of the parasitic diode. Yes. In addition, in the appropriate remaining capacity range of the lead storage battery and the appropriate remaining capacity range of the second storage battery, the voltage obtained by subtracting the barrier voltage due to the parasitic diode from the open voltage of the lead storage battery matches the open voltage of the second storage battery ( The open-circuit voltage and internal resistance of the lead storage battery and the second storage battery are set so that there is a coincidence point).

  According to this prior application, at the time of discharging, the terminal voltage in the appropriate range of the remaining capacity of the lead storage battery and the terminal voltage in the appropriate range of the remaining capacity of the second storage battery are substantially the same, and a large potential difference between the two storage batteries is No longer occurs. Therefore, while abolishing the DCDC converter, which has been indispensable in the past, the amount of current flowing from the high voltage battery to the low voltage battery of both storage batteries can be minimized, so that each battery is overcharged or overdischarged. The risk of becoming a state can be suppressed. Therefore, the DCDC converter is not required and a sufficient cost reduction can be achieved.

  Furthermore, according to the prior application invention, when the MOS-FET is turned off, the coincidence point is shifted to the lower limit side by the amount of the barrier voltage. Therefore, the region on the upper limit side from the coincidence point in the appropriate range of the second storage battery can be expanded, and as a result, the chance of being discharged from the second storage battery in preference to the lead storage battery can be increased. Therefore, the free capacity (acceptance capacity) of the second storage battery that can be charged during regeneration can be increased, and the capacity for recovering regenerative power can be increased.

  Further, when the MOS-FET is turned off, the current flows from the second storage battery to the starter motor that is electrically connected to the MOS-FET on the opposite side of the second storage battery (the lead storage battery side). It can be blocked by the rectifying means of the FET.

  Here, if the lead storage battery and the second storage battery are overdischarged or overcharged beyond the appropriate range, there is a concern about early deterioration of these storage batteries. However, in the above-mentioned prior application invention, the circuit configuration and control for making it within the appropriate range have not been sufficiently studied, and there is room for improvement.

  This invention is made | formed in order to solve the said subject, The objective is providing coexistence with the suppression of deterioration of a lead storage battery, and cost reduction by providing a high performance storage battery (2nd storage battery) in addition to a lead storage battery. To provide a vehicle-mounted power supply device that can realize a sufficient cost reduction by eliminating the DCDC converter that has been required in the past in the vehicle-mounted power supply device that has been planned, and that suppresses overdischarge or overcharge of both storage batteries. It is in.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  In the invention of claim 1, a generator capable of regenerative power generation by regenerative energy, power generation control means for variably controlling the voltage of power output from the generator to a set voltage, and the power generator are electrically connected, A lead storage battery capable of charging the power of the set voltage controlled by the power generation control means, and the lead storage battery electrically connected in parallel to the power of the set voltage controlled by the power generation control means And a second storage battery having a higher output density or energy density than the lead storage battery.

  A first opening / closing means that is electrically connected between the generator, the lead storage battery, and the second storage battery, and that switches between energization and disconnection between the generator and the second storage battery; and in parallel with the first opening / closing means. And a rectifying unit that is arranged so that a direction in which a current flows from the lead storage battery to the second storage battery is a forward direction and has a barrier voltage with respect to the current flowing in the forward direction.

  Furthermore, the second opening / closing means that is electrically connected between the first opening / closing means and the second storage battery to switch between energization and interruption of the second storage battery, the first remaining capacity that is the remaining capacity of the lead storage battery, and the The operating state of the first opening / closing means and the second opening / closing means and the set voltage by the power generation control means are controlled so that the second remaining capacity, which is the remaining capacity of the second storage battery, falls within the appropriate range. And an optimization control means.

<Effects of first opening / closing means and rectifying means>
According to the above invention, since the first opening / closing means and the rectifying means are provided, the same effect as the above-mentioned prior invention is exhibited. First, the effect will be described with reference to FIG.

  The horizontal axis in FIG. 2 (b) shows the SOC of the lithium storage battery (second storage battery), and the solid line A2 in the figure is a voltage characteristic line showing the relationship between the SOC of the lithium storage battery and the open circuit voltage V0 (Li). . A solid line A1 in the figure is a voltage characteristic line showing a relationship between the SOC of the lead storage battery and the open circuit voltage V0 (Pb). The 0% position on the horizontal axis indicating the SOC of the lithium storage battery corresponds to SOC = 88% of the lead storage battery.

  2B indicates a point where the open-circuit voltages of both batteries match when the rectifying means is not provided, contrary to the above invention. When the SOC of the lithium storage battery is lower than the point Vds in the SOC usage range W2 (Li), the terminal voltage Vd (Pb) of the lead storage battery becomes higher than the terminal voltage Vd (Li) of the second storage battery. The second storage battery is discharged from the lead storage battery without being discharged. Therefore, in order to increase the chance of discharging from the second storage battery in preference to the lead storage battery, the point Vds may be positioned as close to the lower limit side of the SOC usage range W2 (Li) as possible.

  In the above invention in view of this point, by providing the rectifying means (for example, a diode), the point where the open-circuit voltages of the two storage batteries coincide with each other by the amount of the barrier voltage Vbar of the rectifying means is shifted to the lower limit side (see reference sign Vds ′). ). In other words, the voltage characteristic line A1 of the lead storage battery apparently shifts to the low voltage side as shown by the one-dot chain line in FIG. Therefore, in the SOC usage range W2 (Li) of the lithium storage battery, the area (discharge area W2d) on the upper limit side from the point Vds ′ can be expanded as indicated by reference sign W2d ′. The opportunity to be discharged from the second storage battery can be increased.

  Here, among the various electric loads mounted on the vehicle, the power required by the starter motor is extremely large. Thus, if it is going to supply electric power from a 2nd storage battery with respect to an electric load with large electric power, compared with a lead storage battery, it will become the hindrance of the small capacity reduction of a 2nd storage battery. Therefore, it is desirable to supply electric power from a lead storage battery for an electric load with high power consumption such as a starter motor.

  In the above invention in view of this point, since the rectifying means (for example, a diode) is arranged so that the direction in which the current flows from the lead storage battery to the second storage battery is the forward direction, the electric load (starter motor) to be supplied with power from the lead storage battery Is electrically connected to the rectifying means on the opposite side of the second storage battery (lead storage battery side), the rectifying means prevents current from flowing from the second storage battery to an electric load such as a starter motor. it can.

<Operational effects of the second opening / closing means and the optimization control means>
Here, when it is desired to avoid overcharging of the second storage battery so that no current flows from the generator to the second storage battery, the current is supplied to the second storage battery through the rectifying means only by shutting off the first opening / closing means. I am concerned that it will flow in. In particular, when the set voltage is increased to charge the lead storage battery, the set voltage is likely to be higher than the value obtained by adding the barrier voltage to the terminal voltage of the second storage battery, and the above-mentioned concern is significant. Become.

  According to the above-mentioned invention in view of this point, since the second opening / closing means is provided, when it is desired to prevent the current from flowing from the generator to the second storage battery, the second opening / closing means may be shut off. This can eliminate the above-mentioned concerns. Since the optimization control means is provided, the operating state and set voltage of the first opening / closing means and the second opening / closing means are controlled so that the first remaining capacity and the second remaining capacity are within the appropriate ranges. Moreover, it can suppress that SOC of a lead storage battery and a 2nd storage battery exceeds an appropriate range, and is overdischarged or overcharged, and can suppress early deterioration of these storage batteries.

  According to a second aspect of the present invention, when the second remaining capacity is lower than the appropriate range, the optimization control unit energizes the first opening / closing unit and the second opening / closing unit to energize the generator. To the second storage battery.

  According to this, when the second storage battery is in an overdischarged state, the second storage battery is charged to increase the second remaining capacity to an appropriate range, and the overdischarged state of the second storage battery can be quickly eliminated. .

  According to a third aspect of the present invention, the optimization control means sets the set voltage when the second remaining capacity is lower than the appropriate range and the first remaining capacity is lower than the appropriate range. By making it higher than the terminal voltage of the lead storage battery, the lead storage battery is charged from the generator.

  According to this, when the second storage battery is in an overdischarged state and the lead storage battery is in an overdischarged state (see FIG. 6 (1)), the lead storage battery can be charged while charging the second storage battery as described above. The overdischarge state of the lead storage battery can also be canceled while the overdischarge state of the second storage battery is eliminated.

  In the invention according to claim 4, when the second remaining capacity is lower than the appropriate range and the first remaining capacity is higher than the appropriate range, the optimization control unit sets the set voltage. The lead storage battery is discharged by making it lower than the terminal voltage of the lead storage battery.

  According to this, when the second storage battery is in an overdischarged state and the lead storage battery is in an overcharged state (see FIG. 6 (3)), the second storage battery can be charged and discharged from the lead storage battery as described above. Therefore, the overcharged state of the lead storage battery can be resolved while the overdischarged state of the second storage battery is eliminated. In addition, when the above-mentioned “when the second storage battery is in an overdischarged state and the lead storage battery is in an overcharged state”, it is assumed that the terminal voltage of the second storage battery is sufficiently lower than the terminal voltage of the lead storage battery. Therefore, even if the set voltage is made lower than the terminal voltage of the lead storage battery in the above invention, since the terminal voltage of the second storage battery should be lower than the set voltage, the second storage battery is charged. .

  In the invention according to claim 5, when the second remaining capacity is lower than the appropriate range and the first remaining capacity is within the appropriate range, the optimization control unit sets the set voltage. Charging / discharging from the lead storage battery is suppressed by controlling to match the terminal voltage of the lead storage battery.

  According to this, when the second storage battery is in an overdischarged state and the lead storage battery is in an appropriate state of charging (see FIG. 6 (2)), the charging from the lead storage battery is performed while charging the second storage battery as described above. Since the discharge is suppressed, the remaining capacity of the lead storage battery can be maintained within an appropriate range while eliminating the overdischarge state of the second storage battery.

  According to a sixth aspect of the present invention, the optimization control unit is configured to perform the second opening / closing operation when the second remaining capacity is within the appropriate range and the first remaining capacity is higher than the appropriate range. The charging of the second storage battery from the generator is avoided by blocking the means, and the lead storage battery is discharged by making the set voltage lower than the terminal voltage of the lead storage battery. .

  According to this, in the case where the second storage battery is in a charged state in an appropriate range and the lead storage battery is in an overcharged state (see FIG. 6 (8)), the second opening / closing means is cut off to switch from the generator to the second storage battery. Therefore, it is possible to eliminate the concern that “the second storage battery is charged through the rectifying means only by blocking the first opening / closing means”. Moreover, since a lead storage battery is discharged by making a setting voltage lower than the terminal voltage of a lead storage battery, the remaining capacity of a 2nd storage battery can be maintained in an appropriate range, eliminating the overcharge state of a lead storage battery.

  When the second opening / closing means is shut off as described above, the first opening / closing means is energized, so that the first opening / closing means is electrically connected to the second storage battery side. It is desirable to supply power from a generator or lead acid battery.

  According to a seventh aspect of the present invention, the optimization control unit is configured to perform the second opening / closing operation when the second remaining capacity is within the appropriate range and the first remaining capacity is lower than the appropriate range. By interrupting the means, charging from the generator to the second storage battery is avoided, and charging from the generator to the lead storage battery is performed by making the set voltage higher than the terminal voltage of the lead storage battery. It is characterized by.

  According to this, in the case where the second storage battery is in an appropriate range of charge and the lead storage battery is in an overdischarged state (see FIG. 6 (7)), the second opening / closing means is cut off to switch from the generator to the second storage battery. Therefore, it is possible to eliminate the concern that “the second storage battery is charged through the rectifying means only by blocking the first opening / closing means”. Moreover, since a lead storage battery is charged by making a setting voltage higher than the terminal voltage of a lead storage battery, the remaining capacity of a 2nd storage battery can be maintained in an appropriate range, eliminating the overdischarge state of a lead storage battery.

  When the second opening / closing means is shut off as described above, the first opening / closing means is energized, so that the first opening / closing means is electrically connected to the second storage battery side. It is desirable to supply power from a generator or lead acid battery.

  In the invention according to claim 8, when the second remaining capacity is higher than the appropriate range, the optimization control means shuts off the first opening / closing means to switch the generator to the second storage battery. And the second storage battery is discharged by energizing the second opening / closing means.

  According to this, when the second storage battery is in an overcharged state, the second storage battery is discharged and the second remaining capacity is lowered to an appropriate range, so that the overcharged state of the second storage battery can be quickly eliminated. .

  According to a ninth aspect of the present invention, the optimization control unit is configured to provide the second remaining capacity when the second remaining capacity is higher than the appropriate range and the first remaining capacity is lower than the appropriate range. The set voltage is set to be equal to or higher than the terminal voltage of the lead storage battery and lower than the value obtained by adding the barrier voltage to the terminal voltage of the second storage battery until the capacity decreases to the appropriate range. The second storage battery is discharged while avoiding discharge from the lead storage battery.

  Here, in the hardware configuration of the invention, that is, the configuration including the generator, the power generation control means, the lead storage battery, the second storage battery, the first opening / closing means, the rectifying means, and the second opening / closing means, the overcharged lead storage battery is charged. If it is attempted to carry out simultaneously and discharging from the overcharged second storage battery, the following problems are concerned. That is, when the set voltage is increased to charge the lead storage battery, the generated power flows into the second storage battery through the rectifying means, and the second storage battery is charged.

  Therefore, in the optimization control means of the above invention, when the second storage battery is in an overcharged state and the lead storage battery is in an overdischarged state (see FIG. 6 (4)), “terminal voltage of the lead storage battery” ≦ “set voltage” < By controlling the set voltage so as to be “a value obtained by adding the barrier voltage to the terminal voltage of the second storage battery”, the second storage battery is discharged while avoiding the discharge from the lead storage battery. According to this, first, the second storage battery is discharged to eliminate the overcharged state, and then the lead storage battery is charged to an appropriate range. In other words, when both storage batteries are outside the proper range, discharging the second storage battery to return to the proper range has priority over charging the lead storage battery to return to the proper range. I can say that.

  In the first place, as mentioned above, when a vehicle is parked, etc., a high-performance storage battery (second storage battery) can be obtained by implementing an inexpensive lead storage battery for power supply (dark current supply) required for a long time. The background of the invention described above is to reduce the capacity and suppress the cost increase. Therefore, since the capacity of the second storage battery is much smaller than that of the lead storage battery, the time required to return the second storage battery outside the proper range to the proper range is the time required to return the lead storage battery to the proper range. It can be shorter than the time required.

  In the above-mentioned invention in view of this point, discharging the second storage battery to return to the proper range as described above is given priority over charging to return the lead storage battery to the proper range. It can be returned to the proper range. In addition, when the second storage battery is overcharged, the regenerative power cannot be recovered sufficiently, but in the above invention, the overcharged state of the second storage battery can be quickly eliminated, so that the state where the regenerative power cannot be recovered is quickly avoided. It is possible and suitable.

  In the invention according to claim 10, when the second remaining capacity is higher than the appropriate range and the first remaining capacity is higher than the appropriate range, the optimization control unit sets the set voltage. The lead storage battery is discharged by making it lower than the terminal voltage of the lead storage battery.

  According to this, when the second storage battery is overcharged and the lead storage battery is overcharged (see FIG. 6 (6)), the second storage battery is discharged by energizing the second opening / closing means as described above. On the other hand, since the lead storage battery can be charged, the overcharged state of the lead storage battery can also be canceled while the overcharged state of the second storage battery is eliminated.

  In the invention according to claim 11, when the second remaining capacity is higher than the appropriate range and the first remaining capacity is within the appropriate range, the optimization control unit sets the set voltage. Charging / discharging from the lead storage battery is suppressed by controlling to match the terminal voltage of the lead storage battery.

  According to this, when the second storage battery is in an overcharged state and the lead storage battery is in a charged state in an appropriate range (see FIG. 6 (5)), the second storage battery is turned on by energizing the second opening / closing means as described above. Since charging and discharging from the lead storage battery are suppressed while discharging, the remaining capacity of the lead storage battery can be maintained within an appropriate range while eliminating the overcharged state of the second storage battery.

  The invention according to claim 12 includes third open / close means that is electrically connected between the generator and the lead storage battery and switches between energization and shutoff of the lead storage battery, and the optimization control means includes the lead storage battery. The first opening / closing means, the second opening / closing means, and the third opening / closing means so that a first remaining capacity that is a remaining capacity and a second remaining capacity that is a remaining capacity of the second storage battery are within the appropriate ranges. And controlling the set voltage by the power generation control means.

  According to this, the remaining capacity of both storage batteries can be finely controlled. For example, if the third opening / closing means is shut off and the first and second opening / closing means are energized, power is supplied from the lead storage battery to the electrical load electrically connected to the lead storage battery side with respect to the first opening / closing means. And the power can be supplied from the second storage battery. Therefore, the discharge from the second storage battery can be promoted, and the second storage battery in an overcharged state can be quickly discharged to an appropriate range.

  The invention according to claim 13 includes third open / close means that is electrically connected between the generator and the lead storage battery and switches between energization and shutoff of the lead storage battery, and the optimization control means includes the second remaining battery. When the capacity is higher than the appropriate range, the second storage battery is discharged by energizing the second opening / closing means, and the first opening / closing means is energized while the third opening / closing means is shut off. Thus, the second storage battery is also discharged to the lead storage battery side with respect to the first opening / closing means.

  According to this, when the second storage battery is in an overcharged state, the power supply from the lead storage battery is shut off with respect to the electrical load electrically connected to the lead storage battery side with respect to the first opening / closing means. Electric power can be supplied from the storage battery. Therefore, the discharge from the second storage battery can be promoted, and the second storage battery in an overcharged state can be quickly discharged to an appropriate range.

  However, when energizing the first and second opening / closing means in this way, if the set voltage is higher than the terminal voltage of the second storage battery, there is a concern that current flows from the generator to the second storage battery. Is done.

  With respect to this concern, in the invention according to claim 14, when the second remaining capacity is higher than the appropriate range, the optimization control means sets the set voltage lower than the terminal voltage of the second storage battery. Thus, charging from the generator to the second storage battery is avoided. Therefore, discharge from the second storage battery can be promoted while eliminating the above-mentioned concerns.

  The invention according to claim 15 further comprises regenerative control means for energizing both the first opening and closing means and the second opening and closing means in order to recharge the electric power regenerated by the generator to the second storage battery, Even if the generator is in a state capable of regenerative power generation, if at least one of the first remaining capacity and the second remaining capacity is not within the appropriate range, the regenerative charging by the regenerative control means is prioritized, Control by the optimization control means is performed.

  According to the above invention, priority is given to setting the regenerative charge within the appropriate range rather than increasing the regenerative charge, and therefore it is possible to promote avoiding both storage batteries from being overcharged and discharged, which is preferable.

  In the invention according to claim 16, an optimal positive range is set as a range in which the first remaining capacity and the second remaining capacity are optimal in the appropriate range, and the first remaining capacity and the second remaining capacity are set. When the remaining capacity is within the proper range and outside the optimum positive range, the first opening and closing means and the second opening means and the second remaining capacity are set so that the first remaining capacity and the second remaining capacity are within the optimum positive range. (2) Optimizing correction control means for controlling the operating state of the opening / closing means and the set voltage by the power generation control means.

  According to the above invention, the optimum positive range is set as the optimum remaining capacity range in the appropriate range, and even if the first and second remaining capacities are in the appropriate range, Therefore, the frequency of going out of the proper range can be reduced, and the avoidance of both storage batteries being overcharged / discharged can be further promoted.

  The invention according to claim 17 comprises regenerative control means for energizing both the first opening and closing means and the second opening and closing means in order to recharge the power regenerated by the generator to the second storage battery, Even when at least one of the first remaining capacity and the second remaining capacity is not in the optimum positive range, if the generator is in a regenerative power generation state, it takes priority over the control by the optimum correction control means. The regenerative charging is performed by the regenerative control means.

  When both the remaining capacities are not within the optimum positive range, unlike the case where they are not within the proper range, the urgency of discharging or charging the storage battery is not required. According to the above-mentioned invention in view of this point, priority is given to increasing the regenerative charge rather than to within the optimum positive range, which is preferable because the regenerative charge amount can be increased.

  According to an eighteenth aspect of the present invention, there is provided temperature detecting means for detecting the temperature of the rectifying means, and when the temperature detected by the temperature detecting means exceeds the upper limit temperature, the first opening / closing means is It is characterized by energizing and shutting off the second opening / closing means.

  When the first opening / closing means is shut off, the lead storage battery and the second storage battery are connected via the rectification means. However, when a current flows through the rectification means, energy loss (“barrier voltage Vbar × current ") Occurs as Joule heat. When a current continues to flow through the rectifying means, the rectifying means overheats due to heat generated as a loss, and there is a concern about thermal damage of the rectifying means (for example, MOS-FET).

  On the other hand, according to the above-described invention, when the rectifying means reaches the upper limit temperature or higher, the first opening / closing means connected in parallel to the rectifying means is energized. Thermal damage due to temperature rise can be prevented.

  However, when the first opening / closing means is energized, the barrier voltage Vbar disappears in the electrical connection between the lead storage battery and the second storage battery, so charging from the lead storage battery to the second storage battery occurs, and the second storage battery becomes overcharged. There is concern. With respect to this concern, in the above invention, since the first opening / closing means is energized and the second opening / closing means is shut off, the above-mentioned concern such as overcharging of the second storage battery can be solved.

The electric block diagram which shows the vehicle-mounted power supply device concerning 1st Embodiment of this invention. (A) shows the appropriate range of a lead acid battery, (b) is a figure which shows the appropriate range of a lithium storage battery. The figure explaining the difference in IV characteristic of a lead storage battery and a lithium storage battery. 5 is a flowchart for explaining conditions under which optimization control, optimal correction control, and normal control are performed in the first embodiment. The flowchart which shows the procedure of the normal control of FIG. The figure explaining the control content by the optimization control means of 1st Embodiment. The figure explaining the control content by the optimal correction | amendment control means of 1st Embodiment. The electric block diagram which shows the vehicle-mounted power supply device concerning 2nd Embodiment of this invention. The figure explaining the control content by the optimization control means of 2nd Embodiment. The electric block diagram which shows the vehicle-mounted power supply device concerning 3rd Embodiment of this invention. The electric block diagram which shows the vehicle-mounted power supply device concerning 4th Embodiment of this invention.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
A vehicle on which the in-vehicle power supply device according to the present embodiment is mounted is a vehicle that uses an internal combustion engine as a travel drive source. When a predetermined automatic stop condition is satisfied, the internal combustion engine is automatically stopped, and a predetermined automatic restart condition is established. The engine has an idle stop function that automatically restarts the internal combustion engine when the condition is satisfied. Although a starter motor that rotates the crankshaft at the start of the internal combustion engine is mounted, a travel motor that assists vehicle travel is not mounted.

  As shown in FIG. 1, the vehicle includes an alternator 10 (generator), a regulator 11 (power generation control means), a lead storage battery 20, a lithium storage battery 30 (second storage battery), various electric loads 41, which will be described below. 42, 43, MOS-FET 50 (first opening / closing means, rectifying means) and relay 60 (second opening / closing means) are mounted. These lead storage battery 20, lithium storage battery 30 and electrical loads 41-43 are connected to the alternator 10. Are electrically connected in parallel.

  The MOS-FET 50 is disposed between the alternator 10 and the lead storage battery 20 and the lithium storage battery 30, and is a first opening / closing that switches energization (on) and shutoff (off) of the lithium storage battery 30 to the alternator 10 and lead storage battery 20. Functions as a means.

  Further, it can be said that the MOS-FET 50 inevitably has a rectifying means because of its internal structure. That is, it can be said that the internal circuit of the MOS-FET 50 is equivalent to a circuit in which the semiconductor switch unit 52 (first opening / closing means) and the parasitic diode 51 (rectifying means) are connected in parallel. Note that an input signal to the gate of the semiconductor switch unit 52 is controlled by the microcomputer 70. That is, the on-operation (energization operation) and the off-operation (shut-off operation) of the MOS-FET 50 are controlled to be switched by the microcomputer (microcomputer 70).

  On the other hand, the relay 60 is an electromagnetic relay having a mechanical contact and does not have a rectifying means. The ON operation (energization operation) and OFF operation (shut-off operation) of the relay 60 are controlled to be switched by the microcomputer 70.

  The load indicated by reference numeral 43 among the electric loads 41 to 43 is a constant voltage required electric load 43 that is required to be stable so that the voltage of the supplied power is substantially constant or at least fluctuates within a predetermined range. The FET 50 is electrically connected to the lithium storage battery 30 side. Thereby, the lithium storage battery 30 shares the power supply to the constant voltage demand electric load 43.

  Specific examples of the constant voltage demand electric load 43 include a navigation device and an audio device. For example, when the voltage of the supplied power is not constant but fluctuates greatly, or fluctuates greatly beyond the predetermined range, the navigation device or the like is activated when the voltage instantaneously drops below the minimum operating voltage. Causes a problem of resetting. Therefore, the power supplied to the constant voltage required electrical load 43 is required to be stable at a constant value that does not drop below the minimum operating voltage.

  Among the electric loads 41 to 43, a load indicated by reference numeral 41 is a starter motor that starts the internal combustion engine, and a load indicated by reference numeral 42 is a general electric load other than the constant voltage required electric load 43 and the starter motor 41. Specific examples of the general electric load 42 include wipers such as a headlight and a front windshield, a blower fan for an air conditioner, a heater for a defroster for a rear windshield, and the like.

  The starter motor 41 and the general electric load 42 are electrically connected to the lead storage battery 20 side with respect to the MOS-FET 50. As a result, the lead storage battery 20 shares power supply to the starter motor 41 and the general electric load 42.

  The power supplied to the starter motor 41 is orders of magnitude greater than the power supplied to the other electric loads 42 and 43. For this reason, when power is supplied to the starter motor 41, the terminal voltage Vd (Pb) of the lead storage battery 20 rapidly decreases. However, the lithium storage battery 30 is provided with the MOS-FET 50 that switches between energization and interruption from the lithium storage battery 30 to the starter motor 41, thereby avoiding a rapid decrease in the terminal voltage Vd (Li).

  Specifically, during the period when power is supplied from the lead storage battery 20 to the starter motor 41, the MOS-FET 50 is turned off by the microcomputer 70, thereby preventing current from flowing from the lithium storage battery 30 to the starter motor 41. The voltage drop of the lithium storage battery 30 is avoided. Therefore, stable electric power with small voltage fluctuation can be supplied from the lithium storage battery 30 to the constant voltage required electrical load 43.

  In addition, when the lead storage battery 20 does not have a sufficient storage amount for starting the starter motor 41, the MOS-FET 50 may be turned on to supply power from the lithium storage battery 30 to the starter motor 41. . In short, when the SOC of the lead storage battery 20 is low, power is supplied from the lithium storage battery 30 to the starter motor 41 in preference to the power supply to the constant voltage required electrical load 43.

  Although the microcomputer 70 normally turns off the MOS-FET 50, the relay 60 is turned on when it is desired to charge a large amount of current into the lithium storage battery 30 or to discharge the lithium storage battery 30 to the lead storage battery 20. The MOS-FET 50 is turned on while being turned on. For example, based on information such as the SOC of the lithium storage battery 30, the SOC of the lead storage battery 20, and the vehicle speed, when it is desired to efficiently charge the lithium storage battery 30 with a large current such as regenerative power generation during deceleration, the lead storage battery 20 is overdischarged. When it is desired to charge the lead storage battery 20 from the lithium storage battery 30, the microcomputer 70 turns on the MOS-FET 50 and the relay 60.

  When the MOS-FET 50 is turned off and the relay 60 is turned on, the current charged / discharged from the lithium storage battery 30 is rectified by the parasitic diode 51. That is, when the MOS-FET 50 is turned off and the relay 60 is turned on, a current may flow from the alternator 10 or the lead storage battery 20 to the lithium storage battery 30, but a current flows from the lithium storage battery 30 to the alternator 10 or the lead storage battery 20. There is nothing.

  In addition, since the parasitic diode 51 has a barrier voltage Vbar (voltage necessary for causing electric conduction at a junction of two different materials such as a pn junction), the power flowing through the parasitic diode 51 is equivalent to the barrier voltage Vbar. A voltage drop occurs. Therefore, when the MOS-FET 50 is turned off and the relay 60 is turned on, the voltage obtained by subtracting the barrier voltage Vbar from the voltage of the power generated by the alternator 10 or the terminal voltage Vd (Pb) of the lead storage battery 20 is the lithium storage battery 30. When the terminal voltage Vd (Li) is higher, current flows into the lithium storage battery 30 through the parasitic diode 51, and the lithium storage battery 30 is charged.

  However, if the MOS-FET 50 is turned off when the alternator 10 is generated and charged by the regenerative energy of the vehicle, a large current flows into the lithium storage battery 30 through the parasitic diode 51, so that the generated current flows through the parasitic diode 51. The energy loss (electric power corresponding to “barrier voltage Vbar × generated current”) that occurs at the time becomes extremely large. Therefore, in the present embodiment, when the alternator 10 is generated by regenerative energy and charged by the lithium storage battery 30, the MOS-FET 50 and the relay 60 are turned on. As a result, the generated current flows into the lithium storage battery 30 by bypassing the parasitic diode 51. Therefore, since the loss due to the barrier voltage Vbar can be eliminated, the loss of power generated by the alternator 10 can be reduced.

  Further, when it is desired to charge the lead storage battery 20 by supplying power from the lithium storage battery 30 or when the lead storage battery 20 has a small SOC, the power supply from the lead storage battery 20 to the general electric load 42 and the starter motor 41 is insufficient. Even when it is desired to supply power from the lithium storage battery 30, the MOS-FET 50 and the relay 60 are turned on. When the terminal voltage Vd (Pb) of the lead storage battery 20 is lower than the terminal voltage Vd (Li) of the lithium storage battery 30, when the MOS-FET 50 and the relay 60 are turned on, power is supplied from the lithium storage battery 30 to the lead storage battery 20. In addition, the power supply to the general electric load 42 or the starter motor 41 can be supplemented.

  The alternator 10 generates electric power using the rotational energy of the crankshaft. Specifically, when the rotor of the alternator 10 is rotated by the crankshaft, an alternating current is induced in the stator coil according to the exciting current flowing through the rotor coil 10a, and is converted into a direct current by a rectifier (not shown). Then, the regulator 11 adjusts the exciting current flowing through the rotor coil 10a, thereby adjusting the voltage of the generated direct current to the set voltage Vreg.

  The electric power generated by the alternator 10 is supplied to various electric loads 41 to 43 and also supplied to the lead storage battery 20 and the lithium storage battery 30. When the drive of the internal combustion engine is stopped and the alternator 10 is not generating power, electric power is supplied from the lead storage battery 20 and the lithium storage battery 30 to the electric loads 41 to 43. The discharge amount from the lead storage battery 20 and the lithium storage battery 30 to the electric loads 41 to 43 and the charge amount from the alternator 10 are overcharged by SOC (State of charge: the ratio of the actual charge amount to the full charge amount). The set voltage Vreg is adjusted and the operation of the MOS-FET 50 and the relay 60 is controlled by an optimization control unit that will be described in detail later so that the range (appropriate range) is not discharged.

  Moreover, in this embodiment, the deceleration regeneration which performs the electric power generation of the alternator 10 with the regenerative energy of a vehicle and makes both storage batteries 20 and 30 (mainly lithium storage battery 30) charge is performed. This deceleration regeneration is performed when a condition such as that the vehicle is in a decelerating state or that the fuel injection to the internal combustion engine is cut is satisfied.

The lead storage battery 20 is a well-known general-purpose storage battery. Specifically, the positive electrode active material is lead dioxide (PbO ₂ ), the negative electrode active material is lead (Pb), and the electrolytic solution is sulfuric acid (H ₂ SO ₄ ). And the some battery cell comprised from these electrodes is connected in series, and is comprised. The storage capacity of the lead storage battery 20 is set larger than the storage capacity of the lithium storage battery 30.

On the other hand, an oxide containing lithium (lithium metal composite oxide) is used for the positive electrode active material of the lithium storage battery 30, and specific examples include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO _{4, and the} like. Can be mentioned. As the negative electrode active material of the lithium storage battery 30, carbon (C), graphite, lithium titanate (for example, Li _x TiO ₂ ), an alloy containing Si or Su, or the like is used. An organic electrolyte is used as the electrolyte of the lithium storage battery 30. And the some battery cell comprised from these electrodes is connected in series, and is comprised. In particular, in the present embodiment, lithium titanate is adopted as the negative electrode active material of the lithium storage battery 30.

In addition, the codes | symbols 21 and 31 in FIG. 1 represent the battery cell aggregate | assembly of the lead storage battery 20 and the lithium storage battery 30, and the codes | symbols 22 and 32 represent the internal resistance of the lead storage battery 20 and the lithium storage battery 30. In the following description, the open voltage V0 of the storage battery is a voltage generated by the battery cell assemblies 21 and 31, and the terminal voltages Vd and Vc of the storage battery are expressed by the following expressions 1 and 2. Voltage.
Vd = V0−Id × R (Formula 1)
Vc = V0 + Ic × R (Formula 2)
The discharge current is Id, the charging current is Ic, the internal resistance of the storage battery is R, and the open voltage of the storage battery is V0. As shown in these equations 1 and 2, the terminal voltage Vd during discharge becomes smaller as the internal resistance R increases, and the terminal voltage Vc during charging becomes larger as the internal resistance R increases.

  Here, since both the storage batteries 20 and 30 are connected in parallel, when charging from the alternator 10, the electromotive current of the alternator 10 flows into the storage battery having a lower terminal voltage Vc. On the other hand, when power is supplied (discharged) to the electrical load 40, the storage battery having the higher terminal voltage Vd is discharged to the electrical load.

  During regenerative charging, the lithium storage battery 30 is given priority over the lead storage battery 20 so that the terminal voltage Vc (Li) of the lithium storage battery 30 becomes lower than the terminal voltage Vc (Pb) of the lead storage battery 20. It is set to be charged. At the time of discharging, the terminal voltage Vd (Li) of the lithium storage battery 30 is higher than the terminal voltage Vd (Pb) of the lead storage battery 20 (more precisely, the voltage obtained by subtracting the barrier voltage Vbar of the parasitic diode 51 from Vd (Pb)). As a result, the lithium storage battery 30 is set to be discharged to the constant voltage required electrical load 43 in preference to the lead storage battery 20.

  These settings can be realized by setting the open circuit voltage V0 and the internal resistance value R of both the storage batteries 20, 30. The open circuit voltage V0 can be set by the positive electrode active material, the negative electrode active material, and the electrolytic solution of the lithium storage battery 30. This can be realized by selecting.

  The details of the setting to increase the chance of Vc (Li) <Vc (Pb) during regenerative charging and Vd (Li)> Vd (Pb) −Vbar during discharging will be described below with reference to FIGS.

  The horizontal axis in FIG. 2A indicates the SOC of the lead storage battery 20, and the solid line A1 in the figure is a voltage characteristic line indicating the relationship between the SOC of the lead storage battery 20 and the open circuit voltage V0 (Pb). The open circuit voltage V0 (Pb) also increases in proportion to the increase in the amount of charge and the SOC. The horizontal axis in FIG. 2B indicates the SOC of the lithium storage battery 30, and the solid line A2 in the figure is a voltage characteristic line indicating the relationship between the SOC of the lithium storage battery 30 and the open circuit voltage V0 (Li). As the amount of charge increases and the SOC increases, the open circuit voltage V0 (Li) also increases. However, the gradient of the increase is small between the inflection points P1 and P2 (see FIG. 2A).

  When the storage batteries 20, 30 are overcharged or overdischarged, there is a concern about early deterioration. Accordingly, the charge / discharge amount of the storage batteries 20 and 30 is managed by the above-described optimization control means so that the range (appropriate range) is not overcharged / discharged, and the appropriate range W1 (Pb) of the lead storage battery 20 is SOC 88%. The appropriate range W2 (Li) of the lithium storage battery 30 is, for example, SOC 35% to 80%. The upper limit of the appropriate range W2 (Li) is smaller than the upper limit of the appropriate range W1 (Pb), and the lower limit of the appropriate range W2 (Li) is smaller than the lower limit of the appropriate range W1 (Pb).

  Therefore, in the lead storage battery 20, SOC 0% to 88% is a range that causes early deterioration. 2B is also an enlarged view of the dotted line portion (portion indicating the appropriate range W1 (Pb)) of FIG. 2A, and the SOC of the lithium storage battery 30 shown on the horizontal axis of FIG. 2B. The position of 0% corresponds to a value of 88% of the appropriate range W1 (Pb).

  And the lithium storage battery 30 is set so that it may become the voltage characteristic A2 of the lithium storage battery 30 which satisfy | fills the following conditions (a) (b) (c) (d) (e). Specifically, by selecting a combination of the positive electrode active material, the negative electrode active material, and the electrolyte solution of the lithium storage battery 30, the voltage characteristic A2 that satisfies the conditions (a) to (e) can be created.

<Condition (a)>
The point at which the open voltage V0 (Pb) of the lead storage battery 20 and the open voltage V0 (Li) of the lithium storage battery 30 coincide with each other in the proper range W1 (Pb) of the lead storage battery 20 and the proper range W2 (Li) of the lithium storage battery 30 VdS exists. In addition, the coincidence point VdS is present in a region (shelf regions P1 to P2) between the inflection points P1 and P2 where the inclination is small in the voltage characteristic line A2 of the lithium storage battery 30. However, the point at which the open-circuit voltages of the batteries 20 and 30 coincide with each other by the amount of the barrier voltage Vbar shifts to the lower limit side (see the symbol Vds ′ in FIG. 2B). In other words, the voltage characteristic line A1 of the lead storage battery 20 apparently shifts to the low voltage side as shown by the one-dot chain line in FIG.

<Condition (b)>
In the appropriate range W2 (Li) of the lithium storage battery 30, on the upper side of the coincidence point Vds ′, the open voltage V0 (Li) of the lithium storage battery 30 is obtained by subtracting the barrier voltage Vbar from the open voltage V0 (Pb) of the lead storage battery 20. Higher than the voltage in minutes. More specifically, when the coincidence point Vds ′ is present in the shelf areas P1 to P2, the coincidence point Vds ′ is present on the lower limit side of the upper limit (80%) of the appropriate range W2 (Li). The slope of the voltage characteristic line A2 of the lithium storage battery 30 is larger than the slope of the voltage characteristic line A1 of the lead storage battery 20 on the upper limit side of the coincidence point Vds ′ in the appropriate range W2 (Li).

<Condition (c)>
The terminal voltage Vc (Li) when the maximum charging current flows through the lithium storage battery 30 is smaller than the set voltage Vreg controlled by the regulator 11. In other words, the terminal voltage Vc (Li) of the lithium storage battery 30 at the time of charging (see the solid line A3 in FIG. 2B) and the terminal voltage Vc at the upper limit (80%) of the appropriate range W2 (Li). The value of (Li) is smaller than the set voltage Vreg. 2B indicates the voltage drop due to the internal resistance 32 at the upper limit (80%), and corresponds to the term (Ic × R) in the above-described equation 2.

<Condition (d)>
In the appropriate range W2 (Li) of the lithium storage battery 30, the open circuit voltage V0 (Li) of the lithium storage battery 30 is lower than the open circuit voltage V0 (Pb) of the lead storage battery 20 on the lower limit side of the coincidence point Vds ′. More specifically, when the coincidence point Vds ′ is present in the shelf areas P1 to P2, the coincidence point Vds ′ is present on the upper limit side of the lower limit value (35%) of the appropriate range W2 (Li). The slope of the voltage characteristic line A2 of the lithium storage battery 30 is larger than the slope of the voltage characteristic line A1 of the lead storage battery 20 on the lower limit side of the coincidence point Vds ′ in the appropriate range W2 (Li).

<Condition (e)>
In the appropriate range W2 (Li) of the lithium storage battery 30, the range on the upper limit side from the coincidence point Vds ′ is wider than the range on the lower limit side. More specifically, when the coincidence point Vds ′ is present in the shelf areas P1 to P2, the coincidence point Vds ′ is present on the lower limit side of the SOC from the center of the area between the P1 and P2. Therefore, Vd (Li)> Vd (Pb) −Vbar in most of the appropriate range W2 (Li).

  The solid line B1 in FIG. 3 indicates the IV characteristics of the storage battery 20, the solid line B2 indicates the IV characteristics of the lithium storage battery 30, the solid line B3 indicates the set voltage Vreg, and the horizontal axis in FIG. 3 indicates the current values Ic, Id and the vertical axis. Indicates terminal voltages Vc and Vd. In addition, the current Ic at the time of charging is represented by plus, and the current Id at the time of discharging is represented by minus.

  In these IV characteristics B1 and B2, the terminal voltage Vc increases (SOC increases) in proportion to the increase of the charging current Ic, and the terminal voltage Vd decreases (SOC decreases) in proportion to the decrease of the discharge current Id. It represents the situation. The slopes of the IV characteristics B1 and B2 indicate the internal resistance value R. The lithium storage battery 30 has the same internal resistance value R (Li) during charging and discharging, but the lead storage battery 20 is charged. The internal resistance value R (Pb) at the time is larger than the internal resistance value R (Pb) at the time of discharge.

  Then, R (Li) <R (Pb) is set during charging, and R (Li) ≦ R (Pb) is set during discharging. Further, at the time of discharging when the MOS-FET 50 is turned off and the relay 60 is turned on, Vd (Li)> Vd (Pb) −Vbar (Vd (Li)> Vd (Pb) at the time of on operation). When charging is performed when the MOS-FET 50 and the relay 60 are turned on, Vc (Li)> Vc (Pb) is obtained when Ic is in the vicinity of zero, but Vc (Li ) <Vc (Pb) (Vc (Li) + Vbar <Vc (Pb) in the off operation). Such a setting can be realized when the internal resistance value R (Li) of the lithium storage battery 30 at the time of charging is smaller than the internal resistance value R (Pb) of the lead storage battery 20.

  The microcomputer 70 limits the amount of charge to both the storage batteries 20 and 30 so that the actual SOC of the lead storage battery 20 and the lithium storage battery 30 falls within the above-described appropriate ranges W1 (Pb) and W2 (Li). In addition to overcharge protection, both storage batteries 20 and 30 also function as optimization control means for controlling the overdischarge protection by limiting the discharge amount to the second storage battery.

  More specifically, the microcomputer 70 always obtains the detected values of the terminal voltages Vc, Vd or the open voltage V0 (Li) of both the storage batteries 20, 30 and detects them by the current detecting means 71, 72 (see FIG. 1). The current value flowing through both storage batteries 20 and 30 is always acquired. And, for example, when the terminal voltage Vd of the lithium storage battery 30 at the time of discharge is lower than the lower limit voltage, the alternator 10 and the lead storage battery 20 in which the SOC is not reduced by turning on the MOS-FET 50 and the relay 60. What is necessary is just to aim at the overdischarge protection of the lithium storage battery 30 by charging. The lower limit voltage may be set based on a voltage corresponding to the SOC lower limit value (35%) in FIG. Further, when the terminal voltage Vc of the lithium storage battery 30 rises above the upper limit voltage, the MOS-FET 50 is turned off to provide overcharge protection, and the relay 60 is turned on to request a constant voltage from the lithium storage battery 30. What is necessary is just to aim at the discharge promotion to the electric load 43. The upper limit voltage may be set based on a voltage corresponding to the SOC upper limit value (80%) in FIG.

  Further, the microcomputer 70 variably controls the value of the set voltage Vreg of the regulator 11 by outputting a command signal for instructing the value of the set voltage Vreg to the regulator 11 according to the voltage of the lithium storage battery 30. Thereby, overdischarge protection and overcharge protection of the lithium storage battery 30 are achieved. That is, when the voltage of the lithium storage battery 30 is lower than the lower limit voltage, the set voltage Vreg is increased to increase the amount of charge to the lithium storage battery 30 to implement overdischarge protection. Further, when the voltage of the lithium storage battery 30 rises above the upper limit voltage, the overcharge protection is performed by reducing the set voltage Vreg and suppressing the amount of charge to the lithium storage battery 30.

  Next, optimization control and optimum correction to make the SOC (Pb) (first remaining capacity) of the lead storage battery 20 and the SOC (Li) (second remaining capacity) of the lithium storage battery 30 fall within the appropriate ranges. The control will be described with reference to FIGS. The flowcharts of FIGS. 4 and 5 are repeatedly executed by the microcomputer 70 at a predetermined cycle (for example, the calculation cycle performed by the CPU described above or every predetermined crank angle). Also, it is executed on condition that the engine is not stopped.

  First, in step S10 shown in FIG. 4, it is determined whether SOC (Pb) and SOC (Li) are within appropriate ranges W1 and W2. If it is determined that at least one of SOC (Pb) and SOC (Li) is outside the appropriate ranges W1 and W2 (S10: NO), the process proceeds to step S20 (optimization control means), and optimization control (see FIG. 6) is performed so as to be within the appropriate ranges W1 and W2.

  If it is determined that both SOC (Pb) and SOC (Li) are within the appropriate ranges W1 and W2 (S10: YES), the process proceeds to step S30, and SOC (Pb) and SOC (Li) are shown in FIG. It is determined whether or not it is within the optimum positive range W10, W20 shown. The optimal positive ranges W10 and W20 are more optimal ranges of SOC (Pb) and SOC (Li) set in the appropriate ranges W1 and W2, and the lower limits of the optimal positive ranges W10 and W20 are those of the appropriate ranges W1 and W2. The value is higher than the lower limit, and the upper limits of the optimal positive ranges W10 and W20 are set to values lower than the upper limits of the appropriate ranges W1 and W2. In the example of FIG. 7, the optimal positive range W10 is set to 89% to 91%, and the optimal positive range W20 is set to 40% to 60%.

  If it is determined that at least one of SOC (Pb) and SOC (Li) is outside the optimal positive range W10, W20 (S30: NO), step S50 (maximum) is performed on condition that regenerative control is not being performed (S40: NO). The process proceeds to optimization control means) and performs optimal correction control (see FIG. 7), which will be described later, so as to be within the optimal positive ranges W10 and W20.

  When it is determined that both SOC (Pb) and SOC (Li) are within the optimum positive ranges W10 and W20 (S30: YES), or it is determined that regenerative control is being performed (S40: YES), Proceeding to step S60, the normal control shown in FIG. 5 is performed.

  In the normal control of FIG. 5, first, in step S61, it is determined whether or not the above-described deceleration regeneration conditions (the vehicle speed is in a deceleration state, the fuel injection is cut off, etc.) are satisfied. If it is determined that the deceleration regeneration condition is satisfied (S61: YES), in the subsequent step S62 (regeneration control means), the MOS-FET 50 and the relay 60 are turned on so as to charge the regenerative power to the lithium storage battery 30. Note that the set voltage Vreg at this time is set higher than when the regeneration is not performed (for example, Vreg = 14.5 V). As a result, the recovery amount of regenerative power is increased.

  On the other hand, if it is determined that the deceleration regeneration condition is not satisfied (S61: NO), such as during acceleration running or steady running (NO in S61), the SOC (Pb) of the lead storage battery 20 is maintained in the subsequent step S63. Control (SOC (Pb) maintenance control). Specifically, the set voltage Vreg is variably controlled according to the SOC (Pb) of the lead storage battery 20. That is, the set voltage Vreg is lowered when the SOC (Pb) becomes high within the optimum positive range W10, and the set voltage Vreg is raised when the SOC (Pb) becomes low.

  Further, the relay 60 is turned on to supply power from the lithium storage battery 30 to the constant voltage requesting electric load 43. Further, by turning off the MOS-FET 50, as described above with reference to FIG. 2B, the upper limit side region (discharge region) from the point Vds ′ in the SOC usage range W2 (Li) of the lithium storage battery. W2d) can be expanded as indicated by reference symbol W2d ′, and thus the chance of discharging from the lithium storage battery 30 in preference to the lead storage battery 20 can be increased, and the capacity of receiving the lithium storage battery 30 during regeneration is increased. I am trying.

  However, since the alternator 10 is charged from the alternator 10 to the lithium storage battery 30 through the parasitic diode 51 when the set voltage Vreg exceeds the upper limit (for example, 13.5 V), the charging to the lithium storage battery 30 should be avoided. When the set voltage Vreg is variably controlled according to SOC (Pb), the set voltage Vreg is controlled so as not to exceed the upper limit.

  Next, the optimization control executed in step S20 of FIG. 4 will be described using FIG.

  The horizontal axis of FIG. 6 indicates SOC (Li), and the vertical axis indicates SOC (Pb). Regarding SOC (Li) of the lithium storage battery 30, (1), (2), and (3) in the figure are when the SOC (Li) is lower than the appropriate range W2 (SOC (Li) <W2), (4) (5) (6) is when SOC (Li) is higher than the appropriate range W2 (SOC (Li)> W2), and (7), (8) and (9) are when SOC (Li) is within the appropriate range W2 (SOC ( Li) = W2).

  Further, regarding the SOC (Pb) of the lead storage battery 20, (1), (4), and (7) in the figure are when the SOC (Pb) is lower than the appropriate range (SOC (Pb) <W1), (3) (6 ) (8) when SOC (Pb) is higher than the appropriate range (SOC (Pb)> W1), (2) (5) and (9) when SOC (Pb) is within the appropriate range (SOC (Pb ) = W1). Therefore, in step S10 of FIG. 4, in the case of (9), an affirmative determination is made that it is within the appropriate ranges W1, W2, and in the cases of (1) to (8), a negative determination is made that it is not in the appropriate ranges W1, W2.

  First, the cases (1), (2), and (3) where SOC (Li) <W2 will be described. In these cases, the lithium storage battery 30 is charged from the alternator 10 by turning on the MOS-FET 50 and the relay 60.

  In the case of (1), the set voltage Vreg is made higher than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 14 V), so that the lead storage battery 20 is charged from the alternator 10. Since the lead storage battery 20 is selected to have a capacity much larger than that of the lithium storage battery 30, in the case of (1), when charging of both storage batteries 20, 30 is started by the above control, the lithium storage battery There is a high possibility that 30 is charged to an appropriate range before the lead storage battery 20. In that case, the state (7) in FIG. 6 is followed.

  In the case of (3), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), thereby discharging the lead storage battery 20 to the general electric load 42. Since the lead storage battery 20 has a much larger capacity than the lithium storage battery 30, when charging to the lithium storage battery 30 and discharging from the lead storage battery 20 are started by the above control in the case of (3), the lithium storage battery 30 is There is a high possibility that the lead storage battery 20 is within the proper range before the lead storage battery 20. In that case, the state (8) in FIG.

  In the case of (2), the set voltage Vreg is variably controlled so as to coincide with the terminal voltage Vc of the lead storage battery 20 that changes each time. For example, the set voltage Vreg may be variably controlled so that the current value detected by the current detection means 71 becomes zero. Thus, by adjusting to Vreg = Vc (Pb), the lead storage battery 20 is not charged and discharged, and the SOC (Pb) within the proper range is maintained. Incidentally, in the above (1) and (2), the set voltage Vreg is controlled to a preset value (14V or 12.5V).

  Next, the case of (4) (5) (6) where SOC (Li)> W2 will be described. In these cases, the MOS-FET 50 is turned off to avoid charging of the lithium storage battery 30 from the alternator 10. In the cases of (4), (5), and (6), the relay 60 is turned on to discharge from the lithium storage battery 30 to the constant voltage required electric load 43.

  However, strictly speaking, when the set voltage Vreg is larger than the value obtained by adding the barrier voltage Vbar to the terminal voltage Vc (Li) of the lithium storage battery 30 (Vreg> Vc (Li) + Vbar), the alternator 10 to the parasitic diode 51 A current flows into the lithium storage battery 30 through the battery and is charged. Therefore, in the cases (4), (5), and (6), the set voltage Vreg is controlled so that Vreg <Vc (Li) + Vbar.

  In the case of (4), when the set voltage Vreg is made higher than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 14V) in the same manner as in the case of (1), the alternator 10 tries to charge the lead storage battery 20. There is a concern that the lithium storage battery 30 may be charged because the condition “Vreg <Vc (Li) + Vbar” cannot be satisfied. Therefore, in the case of (4), the set voltage Vreg is controlled so as to satisfy “Vreg <Vc (Li) + Vbar” in order to discharge the lithium storage battery 30 with priority over charging the lead storage battery 20. For example, the set voltage Vreg may be variably controlled so that Vreg = Vc (Pb), as in the case of (2).

  Therefore, when the above control is performed in the case of (4), the lithium storage battery 30 is discharged without being charged to the lead storage battery 20, and the state of (7) in FIG. 6 is thereafter performed.

  In the case of (6), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), thereby discharging the lead storage battery 20 to the general electric load 42. Since the lead storage battery 20 has a much larger capacity than the lithium storage battery 30, when charging to the lithium storage battery 30 and discharging from the lead storage battery 20 are started by the above control in the case of (6), the lithium storage battery 30 is more There is a high possibility that the lead storage battery 20 is within the proper range before the lead storage battery 20. In that case, the state (8) in FIG.

  In the case of (5), similarly to the case of (2), the set voltage Vreg is variably controlled so that Vreg = Vc (Pb), so that the lead storage battery 20 is not charged and discharged. Thus, SOC (Pb) within the proper range is maintained. Incidentally, in the above (6), the set voltage Vreg is controlled to a preset value (12.5 V).

  Next, the cases of (7) and (8) where SOC (Li) = W2 will be described. In these cases, by turning off the relay 60, charging from the alternator 10 to the lithium storage battery 30 is avoided, and discharging from the lithium storage battery 30 to the constant voltage requesting electric load 43 is also avoided. Thereby, SOC (Li) of the lithium storage battery 30 is maintained within an appropriate range. Further, in the cases (7) and (8), the MOS-FET 50 is turned on to supply power to the constant voltage required electrical load 43 from the higher voltage of the alternator 10 and the lead storage battery 20.

  In the case of (7), the set voltage Vreg is made higher than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 14V), so that the alternator 10 charges the lead storage battery 20, thereby the state of (9) And later. In the case of (7), electric power is supplied from the alternator 10 to the general electric load 42 and the constant voltage required electric load 43.

  In the case of (8), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), whereby the general electric load 42 and the constant voltage required electric load 43 are changed from the lead storage battery 20. To the state of (9).

  As described above, by executing the optimization control of FIG. 6 in the states (1) to (8) described above, both SOC (Pb) (Li) are set within the appropriate ranges W1 and W2 shown in (9). Can do.

  Next, the optimal correction control executed in step S50 of FIG. 4 will be described using FIG.

  The horizontal axis of FIG. 7 indicates SOC (Li), and the vertical axis indicates SOC (Pb). Regarding SOC (Li) of the lithium storage battery 30, (10), (20), and (30) in the figure are when the SOC (Li) is within the appropriate range W2 but lower than the optimum positive range W20 (SOC (Li) <W20 ), (40), (50), and (60) when SOC (Li) is within the appropriate range W2 but higher than the optimum positive range W20 (SOC (Li)> W20), (70) (80) (90) Indicates a case where SOC (Li) is within the optimum positive range W20 (SOC (Li) = W20).

  Further, regarding the SOC (Pb) of the lead storage battery 20, (10), (40), and (70) in the figure are when the SOC (Pb) is within the appropriate range W1 but lower than the optimum positive range W10 (SOC (Pb) <W10), (30), (60), and (80) are when SOC (Pb) is within the appropriate range W1, but higher than the optimal positive range W10 (SOC (Pb)> W10), (20), (50) ( 90) shows a case where SOC (Pb) is within the optimum positive range W10 (SOC (Pb) = W10). Therefore, in step S30 in FIG. 4, in the case of (90), an affirmative determination is made that it is within the optimal positive range W10, W20, and in the cases of (10) to (80), a negative determination is made that the current is not in the optimal positive range W10, W20. To do.

  First, the case of (10) (20) (30) where SOC (Li) <W20 will be described. In these cases, the same control as in FIGS. 6 (1), (2), and (3) is performed. That is, the lithium storage battery 30 is charged from the alternator 10 by turning on the MOS-FET 50 and the relay 60.

  In the case of (10), the alternator 10 charges the lead storage battery 20 by setting the set voltage Vreg higher than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 14V). In the case of (30), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), thereby discharging the lead storage battery 20 to the general electric load 42. In the case of (20), the set voltage Vreg is variably controlled so as to match the terminal voltage Vc of the lead storage battery 20 that changes each time, so that charging and discharging from the lead storage battery 20 are not performed properly. Maintain SOC (Pb) within range. Incidentally, in the above (10) and (20), the set voltage Vreg is controlled to a preset value (14V or 12.5V).

  Next, the case of (40) (50) (60) where SOC (Li)> W20 will be described. In these cases, the same control as in FIGS. 6 (4), (5) and (6) is performed. That is, by turning off the MOS-FET 50, charging from the alternator 10 to the lithium storage battery 30 is avoided. Further, the relay 60 is turned on to discharge from the lithium storage battery 30 to the constant voltage required electric load 43.

  In the case of (40), the set voltage Vreg is controlled so as to satisfy “Vreg <Vc (Li) + Vbar” in order to discharge the lithium storage battery 30 with priority over the charging of the lead storage battery 20. As a result, the lithium storage battery 30 is discharged without being charged to the lead storage battery 20, and the state (70) in FIG. In the case of (60), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), thereby discharging the lead storage battery 20 to the general electric load 42. In the case of (50), as in the case of (20), the set voltage Vreg is variably controlled so that Vreg = Vc (Pb), so that the lead storage battery 20 is not charged and discharged. Maintain SOC (Pb) within the proper range. Incidentally, in the above (60), the set voltage Vreg is controlled to a preset value (12.5 V).

  Next, the case of (70) (80) where SOC (Li) = W20 will be described. In these cases, the same control as in FIGS. 6 (7) and 6 (8) is performed. That is, by turning off the relay 60, charging from the alternator 10 to the lithium storage battery 30 is avoided, and discharging from the lithium storage battery 30 to the constant voltage required electric load 43 is also avoided. Thereby, SOC (Li) of the lithium storage battery 30 is maintained within an appropriate range. In the cases (70) and (80), the MOS-FET 50 is turned on to supply power to the constant voltage required electric load 43 from the higher voltage of the alternator 10 and the lead storage battery 20.

  In the case of (70), the set voltage Vreg is made higher than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 14V), so that the alternator 10 charges the lead storage battery 20 and thereby the state of (9) And later. In the case of (80), the set voltage Vreg is made lower than the terminal voltage Vc of the lead storage battery 20 (for example, Vreg = 12.5 V), whereby the general electric load 42 and the constant voltage required electric load 43 are changed from the lead storage battery 20. To the state (90).

  As described above, by executing the optimal correction control of FIG. 7 in the states (10) to (80) described above, both SOC (Pb) (Li) are within the optimal positive ranges W10 and W20 shown in (9). can do.

  According to the embodiment described above in detail, the following effects [1] to [16] can be obtained.

  [1] When SOC (Pb) and SOC (Li) deviate from the appropriate ranges W1 and W2 (in the cases (1) to (8) in FIG. 6), the MOS-FET 50 is based on the optimization control in FIG. Since the operations of the relay 60 and the regulator 11 are controlled, it is possible to quickly realize that both SOC (Pb) (Li) are within the appropriate ranges W1 and W2 shown in (9). Therefore, the early deterioration of the lead storage battery 20 and the lithium storage battery 30 resulting from SOC (Pb) and SOC (Li) being outside the appropriate ranges W1 and W2 can be suppressed.

  [2] In the present embodiment, a relay 60 for switching between energization and interruption of the lithium storage battery 30 is added to the configuration of the prior application of Japanese Patent Application No. 2009-223947. According to this, as in the case of FIG. 6 (7), the relay 60 is turned off for both the charging of the lead storage battery 20 from the alternator 10 and the avoidance of the charging of the lithium storage battery 30. Can be realized. That is, even if Vreg−Vbar> Vc (Li) is caused by increasing the set voltage Vreg to charge the lead storage battery 20, charging of the lithium storage battery 30 is avoided by turning off the relay 60. Can be realized.

  [3] When SOC (Li)> appropriate range W2 and SOC (Pb) <appropriate range W1 (see FIG. 6 (4)), charging the lead storage battery 20 and discharging from the lithium storage battery 30 simultaneously. It is difficult to implement. In the case of FIG. 6 (4), first, the lithium storage battery 30 is discharged to eliminate the overcharged state to the state of FIG. 6 (70), and then the lead storage battery 20 is charged. Can be quickly returned to within the appropriate range W2, and as a result, a state where regenerative power cannot be recovered can be quickly avoided.

  [4] Even when SOC (Pb) and SOC (Li) are within the appropriate ranges W1 and W2, they are out of the optimum positive ranges W10 and W20 (in (10) to (80) of FIG. In this case, since the operations of the MOS-FET 50, the relay 60, and the regulator 11 are controlled based on the optimal correction control of FIG. 7, both SOC (Pb) (Li) are set to the optimal positive ranges W10 and W20 shown in (90). It can be realized quickly. Therefore, the frequency at which SOC (Pb) and SOC (Li) deviate from the appropriate ranges W1 and W2 can be reduced.

  [5] When SOC (Li)> optimal positive range W20 and SOC (Pb) <optimal positive range W10 (see FIG. 7 (40)), charging the lead storage battery 20 and discharging from the lithium storage battery 30 It is difficult to implement simultaneously. In the case of FIG. 7 (40), first, the lead storage battery 20 is charged to the state shown in FIG. 7 (50), and then the lithium storage battery 30 is discharged, so that the SOC (Pb) is rapidly increased. As a result, the opportunity to stop the engine automatically and idle can be increased.

  [6] The voltage characteristic A2 of the lithium storage battery 30 is set so as to satisfy the above condition (a) (the coincidence point Vds exists (Vds ′ exists when the MOS-FET 50 is turned off)) with respect to the voltage characteristic A1 of the lead storage battery 20. It ’s built. Thus, during discharge, the terminal voltage Vd (Pb) in the proper range W1 of the lead storage battery 20 and the terminal voltage Vd (Li) in the proper range W2 of the lithium storage battery 30 are as shown in FIG. Substantially coincides with each other, and no large potential difference occurs between the two storage batteries. Therefore, even if the DCDC converter, which has been conventionally required, is abolished and the MOS-FET 50 is turned on, the amount of current flowing from a battery having a high voltage to a battery having a low voltage can be minimized. Therefore, it is possible to suppress the possibility that each of the batteries 20 and 30 will be in an overcharged state or an overdischarged state, while eliminating the DCDC converter that has been conventionally required. Therefore, a sufficient cost reduction can be realized as much as the DCDC converter can be eliminated.

  [7] By creating the voltage characteristic A2 so as to satisfy the condition (b) (Vd (Li)> Vd (Pb) −Vbar on the upper limit side of the coincidence point Vds ′) with respect to the voltage characteristic A1, the lithium storage battery 30 Is charged to a constant voltage required electric load 43 from the lithium storage battery 30 whose open circuit voltage is higher than that of the lead storage battery 20 in a state where the battery is charged more than the coincidence point Vds ′ within the appropriate range W2. Therefore, since the chance of discharging from the lithium storage battery 30 to the constant voltage required electrical load 43 is given priority over the lead storage battery 20, the cumulative discharge amount from the lead storage battery 20 with low durability against frequent discharge (cumulative discharge amount). Therefore, deterioration of the lead storage battery 20 can be suppressed.

  [8] By creating the voltage characteristic A2 so as to satisfy the above condition (c) (Vc (Li) <Vreg at the maximum charging current) with respect to the voltage characteristic A1, it has priority over the lead storage battery 20 for the following reason. Thus, the opportunity to be charged with the lithium storage battery 30 can be increased. Therefore, the amount of regenerative power recovered can be increased.

  If the lithium storage battery 30 is abolished and the regenerative power is charged by the lead storage battery 20, the internal resistance 22 of the lead storage battery 20 is larger than the internal resistance 32 of the lithium storage battery 30 as shown in FIG. The terminal voltage Vc (Pb) reaches the set voltage Vreg at the time when the voltage rises to the point where it cannot be charged. On the other hand, the lithium storage battery 30 according to this embodiment can be charged because Vc (Li) <Vreg is satisfied even when the charging current becomes maximum. In the example of FIG. 3, the terminal voltage Vc (Li) reaches the set voltage Vreg when the charging current rises to Ib larger than the maximum charging current Imax.

  [9] A voltage characteristic A2 is created so as to satisfy the above condition (d) (Vd (Li) <Vd (Pb) −Vbar on the lower limit side of the coincidence point Vds ′) with respect to the voltage characteristic A1. According to this, when the SOC of the lithium storage battery 30 falls below the coincidence point Vds ′ as a result of preferential discharge from the lithium storage battery 30 to the electrical load 40, the electrical load from the lead storage battery 20 replaces the lithium storage battery 30. 40 will be discharged. In addition, a current flows from the lead storage battery 20 to the lithium storage battery 30, and the lithium storage battery 30 is charged and the SOC is raised toward the coincidence point Vds'. Therefore, it can suppress that the lithium storage battery 30 becomes overdischarged.

  [10] The voltage characteristic A2 is created so as to satisfy the above condition (e) with respect to the voltage characteristic A1 (the upper limit range is wider than the lower limit range from the coincidence point Vds'). According to this, since the range of Vd (Li)> Vd (Pb) −Vbar according to the condition (b) can be secured sufficiently wide, it is possible to sufficiently increase the chances of preferential discharge from the lithium storage battery 30. It is possible to improve the effect of suppressing the deterioration of the lead storage battery 20.

  [11] In the present embodiment, by providing the MOS-FET 50, the point at which the open voltages of both the batteries 20, 30 match is shifted to the lower limit side by the amount of the barrier voltage Vbar of the parasitic diode 51 (Vds → Vds). '). In other words, the voltage characteristic line A1 of the lead storage battery 20 apparently shifts to the low voltage side as shown by the one-dot chain line in FIG. Therefore, in the appropriate range W2 (Li) of the lithium storage battery 30, the upper limit area (discharge area W2d) from the point Vds ′ can be expanded as indicated by reference sign W2d ′, and therefore, the lead storage battery 20 is prioritized. Thus, the chance of discharging from the lithium storage battery 30 to the constant voltage required electric load 43 can be increased.

  [12] Here, among the various electric loads 41 to 43 mounted on the vehicle, the electric power required for the starter motor 41 is extremely large. When power is supplied from the lithium storage battery 30 to an electric load having a large power in this way, the capacity of the lithium storage battery 30 that is more expensive than the lead storage battery 20 is hindered. Thus, in the present embodiment, the power supply to the starter motor 41 with large power consumption is shared by the lead storage battery 20 to reduce the capacity of the lithium storage battery 30. Since the direction of the parasitic diode 51 of the MOS-FET 50 is arranged so that the direction in which current flows from the lead storage battery 20 to the lithium storage battery 30 is the forward direction, it is possible to prevent current from flowing from the lithium storage battery 30 to the starter motor 41. . Moreover, since the MOS-FET 50 is turned off during the operation period of the starter motor 41, it is possible to reliably prevent current from flowing from the lithium storage battery 30 to the starter motor 41.

  [13] When the lithium storage battery 30 is charged from the alternator 10, the MOS-FET 50 is turned on, so that the parasitic diode 51 is bypassed and the generated current is supplied to the lithium storage battery 30 for charging. Therefore, since the loss due to the barrier voltage Vbar of the parasitic diode 51 can be eliminated, the loss of power generated by the alternator 10 can be reduced. In particular, since it is turned on when the lithium storage battery 30 is charged with regenerative power, it is excellent in that power loss due to a large current flowing through the parasitic diode 51 can be reduced.

  [14] As a combination of the positive electrode material and the negative electrode material of the lithium storage battery 30, by using lithium iron phosphate for the positive electrode and graphite for the negative electrode, the above conditions (a), (b), and (c) are satisfied. Since the internal resistance of lithium iron phosphate is higher than that of other materials, the electrode area must be increased in order to satisfy the above conditions (a), (b), and (c). In this embodiment, lithium cobaltate, lithium manganate, lithium nickelate compound, and the like are used as the positive electrode material and lithium titanate is used as the negative electrode material. In this embodiment, the condition (a ) (B) (c) can be satisfied, and the lithium storage battery 30 can be reduced in size and cost.

  However, when lithium titanate is used as the negative electrode material, there is a new problem that the point Vds at which the open-circuit voltages of both batteries match is located on the upper limit side as compared with the case where graphite is used as the negative electrode material. This problem can be solved by shifting the point to the lower limit side (Vds → Vds ′) by providing the MOS-FET 50 as described above. Therefore, according to the present embodiment, it is possible to achieve both the elimination of the problem that the point Vds is positioned on the upper limit side and the reduction of the electrode area.

  [15] The lithium storage battery 30 shares power supply to the constant voltage demand electric load 43, and the lead storage battery 20 shares power supply to the starter motor 41. Since the MOS-FET 50 is turned off during the period in which power is supplied from the lead storage battery 20 to the starter motor 41, stable power with small voltage fluctuation can be supplied to the constant voltage request electric load 43.

  [16] In the present embodiment, the first opening / closing means and the rectifying means according to the present invention are embodied by the MOS-FET 50. Therefore, since the parasitic diode 51 that the MOS-FET 50 necessarily has in its internal structure can be used as the rectifying means, it is unnecessary to provide a diode (rectifying means) separately from the MOS-FET 50.

(Second Embodiment)
In the present embodiment shown in FIG. 8, in addition to the configuration shown in FIG. 1, a relay 61 (third opening / closing means) that is electrically connected between the alternator 10 and the lead storage battery 20 and switches between energization and shutoff of the lead storage battery 20 is provided. . The relay 61 is desirably an electromagnetic relay similar to the second opening / closing means (relay 60). Note that the microcomputer 70 is controlled to switch between the ON operation (energization operation) and the OFF operation (shut-off operation) of the relay 61.

  Also in this embodiment, the same control as in FIGS. 4 and 5 is performed. However, since different control is performed in the cases (4), (5), and (6) when the optimization control shown in FIG. 6 is performed, the difference will be described below with reference to FIG.

  FIG. 9 is a diagram showing the contents of the optimization control according to the present embodiment. In the case of (1) (2) (3) (7) (8) (9), the relay 61 is turned on, and the relay 60, the MOS-FET 50, and the set voltage Vreg are controlled in the same manner as in FIG. Therefore, the same function as in the case of FIG. 6 is exhibited.

  On the other hand, in the cases of (4), (5) and (6), the power supply from the lead storage battery 20 to the general electric load 42 is interrupted by turning off the relay 61. Then, by turning on the MOS-FET 50 and the relay 60, electric power is supplied from the lithium storage battery 30 to the general electric load 42. Thus, according to the present embodiment including the relay 61, the power supply from the lead storage battery 20 to the general electric load 42 can be cut off by turning off the relay 61. Therefore, the MOS-FET 50 and the relay 60 are connected to each other. Discharging from the lithium storage battery 30 to the general electric load 42 can be realized by turning it on. Therefore, the discharge of the lithium storage battery 30 can be promoted, and the lithium storage battery 30 in an overcharged state can be quickly brought into the appropriate range W2.

  In these cases (4), (5), and (6), the set voltage Vreg is controlled to be lower than the terminal voltage Vc (Li) of the lithium storage battery 30. Thereby, it is avoided that an electric current flows into the lithium storage battery 30 from the alternator 10 and is charged. For example, the set voltage Vreg may be set to a value (for example, 11.8 V) higher than the terminal voltage Vc (Li) when SOC (Li) is the lower limit of the appropriate range W2.

  As described above, according to the present embodiment including the relay 61, in addition to the effect of the first embodiment, the effect that the discharge from the lithium storage battery 30 in the overcharged state can be promoted is exhibited. .

(Third embodiment)
In the first embodiment, the present invention is applied to a vehicle having an idle stop function. However, in the present embodiment, the present invention is applied to a vehicle having no idle stop function.

  And in the said 1st Embodiment, although the constant voltage request | requirement electric load 43 is electrically connected by the side of the lithium storage battery 30 with respect to MOS-FET50, in this embodiment shown in FIG. 43 is electrically connected to the lead-acid battery 20 side with respect to the MOS-FET 50. Thereby, all the electric loads supplied with electric power from the lead storage battery 20 and the lithium storage battery 30 among the electric loads 41, 42, 43 mounted on the vehicle are electrically connected to the lead storage battery 20 side with respect to the MOS-FET 50. The Rukoto.

  According to this, a lithium storage battery is added to an existing in-vehicle power supply device (configuration shown by a one-dot chain line in FIG. 8) configured to include the alternator 10, the regulator 11, various electric loads 41, 42, 43, and the lead storage battery 20. 30, the addition of the MOS-FET 50 and the relay 60 can be changed to an in-vehicle power supply device in which a lithium storage battery 30 is connected in parallel to a lead storage battery 20.

  That is, in the case of the in-vehicle power supply device according to the first embodiment, it is necessary to replace the power supply wiring of the existing constant voltage required electric load 43. In the case of the in-vehicle power supply device according to the present embodiment, Wiring replacement work can be made unnecessary. Therefore, it is possible to reduce the number of changes that require a hardware design change for the existing in-vehicle power supply device.

  Note that, also in the hardware configuration of the present embodiment shown in FIG. 10, the same optimization control and optimum correction control as in the first embodiment are performed. Therefore, the same operations and effects as those of the first embodiment are also exhibited by this embodiment.

(Fourth embodiment)
In this embodiment shown in FIG. 11, instead of the MOS-FET 50 according to each of the above embodiments, an electromagnetic relay 52R and a diode 51a connected in parallel are employed. In this case, the electromagnetic relay 52R corresponds to the first opening / closing means, and the diode 51a corresponds to the rectifying means. The diode 51a has the barrier voltage Vbar in the same manner as the parasitic diode 51 has the barrier voltage Vbar.

  The operation of the switch unit 52a of the electromagnetic relay 52R is controlled by controlling the current flowing to the electromagnetic coil 52b of the electromagnetic relay 52R by the microcomputer 70. In the present embodiment, when a current is passed through the electromagnetic coil 52b, the switch unit 52a is turned on by electromagnetic force, and the alternator 10 and the lead storage battery 20 are energized with the lithium storage battery 30. On the other hand, when the current to the electromagnetic coil 52b is cut off, the switch unit 52a is turned off to cut off the energization of the lithium storage battery 30 to the alternator 10 and the lead storage battery 20.

  Note that, also in the hardware configuration of the present embodiment shown in FIG. 11, the same optimization control and optimum correction control as in the first embodiment are performed. Therefore, the same operations and effects as those of the first embodiment are also exhibited by this embodiment. Further, the first embodiment employing the MOS-FET 50 and the present embodiment employing the electromagnetic relay 52R and the diode 51a have advantages and disadvantages described below.

  That is, when the MOS-FET 50 is employed, the first opening / closing means and the rectifying means can be configured with one electronic component, so that the number of components can be reduced as compared with the case where the electromagnetic relay 52R and the diode 51a are employed. Miniaturization can be achieved. Further, when the MOS-FET 50 is employed, the response of the operation of the semiconductor switch unit 52 to the output of the operation command (gate voltage or excitation current) by the microcomputer 70 is enhanced as compared with the case where the electromagnetic relay 52R is employed. Can do.

  Further, when the MOS-FET 50 is employed, the control terminal (gate terminal) and the controlled terminals (source terminal and drain terminal) of the MOS-FET 50 are not in an insulated state, so that the operating voltage applied to the control terminal Is a voltage obtained by adding a control voltage to the voltage of the controlled terminal, and is generally a high voltage. Therefore, a circuit (not shown) for creating a high voltage for the operating voltage is required. On the other hand, when the electromagnetic relay 52R is employed, since the switch portion 52a and the electromagnetic coil 52b of the electromagnetic relay 52R are in an insulated state, the operating voltage applied to the electromagnetic coil 52b of the electromagnetic relay 52R is high. No voltage is required. Therefore, the high voltage generation circuit for the operating voltage required for the MOS-FET 50 can be eliminated, and the on / off control by the microcomputer 70 can be simplified.

(Fifth embodiment)
In the optimization control of FIG. 7 according to the first embodiment, the set voltage Vreg is controlled to a preset value or to match the terminal voltage Vc of the lead storage battery 20. On the other hand, in the present embodiment, the SOC (Pb) is controlled by variably controlling the set voltage Vreg in accordance with the SOC (Pb) in the same manner as the SOC (Pb) maintenance control performed in step S63 of FIG. The optimum positive range W10 may be set.

  However, it is desirable that the upper limit of the set voltage Vreg when performing this variable control is set higher as the SOC (Pb) is lower. For example, the upper limit is set to 14V in the case of (10), 13.5V in the case of (20), and 12.5V in the case of (30) (60) (80). In the states of (10), (20), and (30), the terminal voltage Vc (Li) of the lithium storage battery 30 should be sufficiently lower than the terminal voltage Vc (Pb) of the lead storage battery 20, so SOC ( If the set voltage Vreg is variably controlled according to (Pb), the MOS-FET 50 and the relay 60 are turned on, so that the lithium storage battery 30 is charged from the alternator 10 regardless of the upper limit value. .

  In the case of (40), it is difficult to simultaneously charge the lead storage battery 20 and discharge the lithium storage battery 30 as in the case of FIG. 6 (4). In the case of (4), the lithium storage battery 30 is discharged with priority over the charging of the lead storage battery 20, whereas in the case of (40), the lead storage battery has priority over the discharge of the lithium storage battery 30. Charge to 20.

  The purpose of the priority will be described below. In the case of (40), although SOC (Li) is outside the optimum positive range W20, but within the proper range W2, the urgency to discharge the lithium storage battery 30 is lower than in the case of (4). On the other hand, if the SOC (Pb) is less than or equal to a predetermined value, the idle stop condition for automatically stopping the engine is not satisfied, and the frequency of idle stop decreases. Therefore, in the case of the above (40), the idling stop frequency is increased by charging the lead storage battery 20 in preference to the discharge of the lithium storage battery 30 with low urgency.

  In the cases of (40), (50), and (60), as in the cases of (10), (20), and (30), the set voltage Vreg is variably controlled according to the SOC (Pb), so that the SOC (Pb) is set to the optimum positive range W10. However, charging of the lithium storage battery 30 is avoided by setting the upper limit of the set voltage Vreg when performing this variable control so as not to satisfy Vd (Pb) −Vbar> Vd (Li). The lower the SOC (Pb), the higher the upper limit is set. For example, the upper limit is set to 14V in the case of (40), 13.5V in the case of (50), and 12.5V in the case of (60). It is desirable.

  In the cases of (70) and (80), as in the cases of (10), (20), and (30), the set voltage Vreg is variably controlled according to the SOC (Pb), so that the SOC (Pb) is The optimum positive range W10 is set. The upper limit of the set voltage Vreg when performing this variable control is set to 14V in the case of (70) and 12.5V in the case of (80).

(Sixth embodiment)
In the present embodiment, the optimum correction control means, when the second remaining capacity is higher than the optimum positive range and the first remaining capacity is lower than the optimum positive range, the first remaining capacity. The set voltage is set higher than the terminal voltage of the lead storage battery until the capacity rises to the optimum positive range, so that the lead storage battery is charged from the generator, and the second opening / closing By blocking the means, charging from the generator to the second storage battery is avoided.

  Then, after the first remaining capacity has risen to the optimum positive range, the second storage battery is discharged by energizing the second opening / closing means, and the set voltage is set to the terminal of the lead storage battery. The charging and discharging from the lead storage battery is suppressed by controlling the voltage to match the voltage and shutting off the first opening / closing means.

  Here, in the configuration including the generator, the power generation control means, the lead storage battery, the second storage battery, the first opening / closing means, the rectifying means, the second opening / closing means, and the third opening / closing means, the overcharged lead storage battery is charged. When trying to simultaneously discharge from the overcharged second storage battery, there are concerns about the following problems. That is, when the set voltage is increased to charge the lead storage battery, the generated power flows into the second storage battery through the rectifying means, and the second storage battery is charged.

  Therefore, in the optimal correction control means according to the present embodiment, when the SOC of the second storage battery is higher than the optimal positive range and the SOC of the lead storage battery is lower than the optimal positive range (see FIG. 7 (40)), first of all. The lead storage battery is charged to increase the first remaining capacity, and then the second storage battery is discharged to the optimum positive range. In short, when both storage batteries are outside the optimum positive range, charging to return the lead storage battery to the optimum positive range is prioritized over discharging to return the second storage battery to the optimum positive range.

  Here, in the idle stop control in which the engine is automatically stopped, the automatic stop is generally prohibited when the first remaining capacity is a predetermined value or less. In this embodiment in view of this point, since the charge of the lead storage battery is prioritized over the discharge of the second storage battery as described above, the SOC (first remaining capacity) of the lead storage battery can be quickly increased. Therefore, it is possible to increase the opportunity to automatically stop the engine.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  -If the MOS-FET 50 is equipped with a temperature sensor (temperature detection means) and the temperature detected by the temperature sensor exceeds the upper limit temperature, it takes precedence over the above-described optimization control and optimum correction control. Then, the MOS-FET 50 is energized. According to this, it is possible to prevent the MOS-FET 50 from being thermally damaged by energizing the MOS-FET 50.

  However, when the MOS-FET 50 is energized in this way, the barrier voltage Vbar disappears in the electrical connection between the lead storage battery 20 and the lithium storage battery 30, so that charging from the lead storage battery 20 to the lithium storage battery 30 is promoted, and the lithium storage battery There is concern that 30 will be overcharged. Therefore, when the MOS-FET 50 is energized as described above, it is desirable to avoid overcharging of the lithium storage battery 30 by cutting off the relay 60.

  In each of the above embodiments, both the optimization control and the optimal correction control are performed. However, if at least the optimization control is performed, the control is simplified without performing the optimal correction control. It may be. That is, in the first embodiment, the normal control of FIG. 5 is performed when it is within the optimal positive range W10, W20 (in the case of FIG. 7 (90)), but the normal control is performed within the appropriate range W1, W2. If it is in the case (in the case of FIG. 6 (9)), it is carried out.

  In each of the above embodiments, when the optimization control is performed, the set voltage Vreg is fixed to a preset value (for example, fixed to 14 V in the case of (1) in FIG. 6), but the lead storage battery 20 The value may be variably controlled according to the terminal voltage.

  In each of the above embodiments, the MOS-FET 50 is employed as an opening / closing means for switching between energization and interruption from the lithium storage battery 30 to the starter motor 41. However, instead of the MOS-FET 50, another semiconductor switch (electric field) such as an IGBT is used. Effect transistor). However, unlike the MOS-FET, the IGBT has a current flowing through the switch only in the direction opposite to the forward direction of the parasitic diode. Therefore, another bypass means is provided to reduce the loss due to the barrier voltage of the parasitic diode. There is a need to. On the other hand, the use of the MOS-FET 50 is advantageous in that the bypass means can be dispensed with.

  -In each above-mentioned embodiment, although the non-aqueous-electrolyte type lithium storage battery 30 is adopted as the 2nd storage battery used as voltage characteristic A2, the 2nd storage battery of the present invention is not limited to lithium storage battery 30, For example, a nickel storage battery using a nickel compound for the electrode may be employed as long as the conditions (a) to (e) are satisfied.

  In each of the above embodiments, the matching point Vds ′ is present on the upper limit side of the lower limit value (35%) of the appropriate range W2 of the lithium storage battery 30, but the matching point Vds ′ is present on the lower limit value. Also good.

  In each of the above embodiments, a vehicle having a regeneration function is targeted, but the present invention can also be applied to a vehicle that does not have a regeneration function. However, in a vehicle having a regenerative function, charging by regeneration is frequently performed. For example, “reducing the accumulated charge amount of the lead storage battery 20 with low durability and suppressing the deterioration of the lead storage battery 20”. An effect is exhibited suitably.

  DESCRIPTION OF SYMBOLS 10 ... Alternator (generator), 11 ... Regulator (power generation control means), 20 ... Lead storage battery, 30 ... Lithium storage battery (2nd storage battery), 51 ... Parasitic diode (rectification means) of MOS-FET, 51a ... Diode (rectification) Means), 52... MOS-FET semiconductor switch section (first opening / closing means), 52R. Electromagnetic relay (first opening / closing means), 60 ... relay (second opening / closing means), 61 ... relay (third opening / closing means), S20: Optimization control means, S50: Optimal correction control means, S62: Regeneration control means.

Claims (18)

A generator capable of regenerative power generation using regenerative energy;
Power generation control means for variably controlling the voltage of the power output from the generator to a set voltage;
A lead storage battery that is electrically connected to the generator and is capable of charging the power of the set voltage controlled by the power generation control means;
A second storage battery that is electrically connected in parallel to the lead storage battery, can be charged with the power of the set voltage controlled by the power generation control means, and has a higher output density or energy density than the lead storage battery. When,
A first opening / closing means that is electrically connected between the generator and the lead storage battery and the second storage battery, and switches between energization and disconnection of the generator and the second storage battery;
Rectifying means connected in parallel with the first opening / closing means, arranged so that the direction of current flow from the lead storage battery to the second storage battery is the forward direction, and having a barrier voltage with respect to the current flowing in the forward direction;
A second opening / closing means that is electrically connected between the first opening / closing means and the second storage battery and switches between energization and interruption of the second storage battery;
The operating states of the first opening / closing means and the second opening / closing means so that the first remaining capacity which is the remaining capacity of the lead storage battery and the second remaining capacity which is the remaining capacity of the second storage battery are within appropriate ranges. And optimization control means for controlling the set voltage by the power generation control means,
A vehicle-mounted power supply device comprising:   The optimization control unit charges the second storage battery from the generator by energizing the first switching unit and the second switching unit when the second remaining capacity is lower than the appropriate range. The in-vehicle power supply device according to claim 1.   When the second remaining capacity is lower than the appropriate range and the first remaining capacity is lower than the appropriate range, the optimization control unit sets the set voltage higher than the terminal voltage of the lead storage battery. The vehicle-mounted power supply device according to claim 2, wherein the lead storage battery is charged from the generator.   When the second remaining capacity is lower than the appropriate range and the first remaining capacity is higher than the appropriate range, the optimization control unit sets the set voltage to be lower than the terminal voltage of the lead storage battery. The in-vehicle power supply device according to claim 2, wherein the lead storage battery is discharged by the operation.   When the second remaining capacity is lower than the appropriate range and the first remaining capacity is within the appropriate range, the optimization control unit matches the set voltage with the terminal voltage of the lead storage battery. The in-vehicle power supply device according to any one of claims 2 to 4, wherein charging and discharging from the lead storage battery are suppressed by controlling the power consumption to be performed.   When the second remaining capacity is within the appropriate range and the first remaining capacity is higher than the appropriate range, the optimization control means shuts off the second opening / closing means to cut off the power generation. The lead storage battery is discharged by causing charging of the second storage battery from a machine to be avoided and making the set voltage lower than a terminal voltage of the lead storage battery. The vehicle-mounted power supply device as described in one.   When the second remaining capacity is within the appropriate range and the first remaining capacity is lower than the appropriate range, the optimization control means shuts off the second opening / closing means to cut off the power generation. The charging from the generator to the lead storage battery is performed by avoiding charging from the generator to the second storage battery and making the set voltage higher than the terminal voltage of the lead storage battery. The vehicle-mounted power supply device according to any one of 6.   When the second remaining capacity is higher than the appropriate range, the optimization control unit suppresses charging from the generator to the second storage battery by blocking the first opening / closing unit, and The in-vehicle power supply device according to any one of claims 1 to 7, wherein the second storage battery is discharged by energizing the second opening / closing means. The optimization control means includes
When the second remaining capacity is higher than the appropriate range and the first remaining capacity is lower than the appropriate range, a period until the second remaining capacity decreases to the appropriate range, The second voltage while avoiding discharge from the lead storage battery by making the set voltage equal to or higher than the terminal voltage of the lead storage battery and lower than the value obtained by adding the barrier voltage to the terminal voltage of the second storage battery. The in-vehicle power supply device according to claim 8, wherein the storage battery is discharged.   When the second remaining capacity is higher than the appropriate range and the first remaining capacity is higher than the appropriate range, the optimization control unit sets the set voltage to be lower than the terminal voltage of the lead storage battery. The in-vehicle power supply device according to claim 8 or 9, wherein the lead storage battery is discharged by the operation.   When the second remaining capacity is higher than the appropriate range and the first remaining capacity is within the appropriate range, the optimization control unit matches the set voltage with the terminal voltage of the lead storage battery. The in-vehicle power supply device according to any one of claims 8 to 10, wherein charging and discharging from the lead storage battery is suppressed by controlling the power consumption. A third opening / closing means that is electrically connected between the generator and the lead-acid battery and switches between energization and interruption of the lead-acid battery;
The optimization control means includes the first opening / closing means so that a first remaining capacity that is a remaining capacity of the lead storage battery and a second remaining capacity that is a remaining capacity of the second storage battery are within the appropriate ranges, The in-vehicle power supply device according to any one of claims 1 to 11, wherein an operation state of the second opening / closing means and the third opening / closing means and the set voltage by the power generation control means are controlled. A third opening / closing means that is electrically connected between the generator and the lead-acid battery and switches between energization and interruption of the lead-acid battery;
When the second remaining capacity is higher than the appropriate range, the optimization control unit discharges the second storage battery by energizing the second opening / closing unit and shuts off the third opening / closing unit. However, by energizing the first opening / closing means, the lead storage battery is also discharged from the second storage battery to the first opening / closing means. The in-vehicle power supply device described in 1.   When the second remaining capacity is higher than the appropriate range, the optimization control unit charges the second storage battery from the generator by setting the set voltage lower than the terminal voltage of the second storage battery. The in-vehicle power supply device according to claim 13, wherein Regenerative control means for energizing both the first opening and closing means and the second opening and closing means to regeneratively charge the electric power regenerated by the generator to the second storage battery;
Even if the generator is in a state where regenerative power generation is possible, if at least one of the first remaining capacity and the second remaining capacity is not within the appropriate range, the regeneration charge by the regeneration control means is prioritized, The in-vehicle power supply device according to claim 1, wherein the control by the optimization control unit is performed. In the appropriate range, an optimal positive range is set as a range in which the first remaining capacity and the second remaining capacity are optimal,
When the first remaining capacity and the second remaining capacity are within the appropriate range and outside the optimum positive range, the first remaining capacity and the second remaining capacity are within the optimum positive range. 16. An optimum correction control means for controlling operating states of the first opening / closing means and the second opening / closing means and the set voltage by the power generation control means. The vehicle-mounted power supply device described in 1. Regenerative control means for energizing both the first opening and closing means and the second opening and closing means to regeneratively charge the electric power regenerated by the generator to the second storage battery;
Even if at least one of the first remaining capacity and the second remaining capacity is not in the optimum positive range, if the generator is in a regenerative power generation state, it takes priority over the control by the optimum correction control means. The in-vehicle power supply device according to claim 16, wherein the regenerative charging is performed by the regeneration control unit. Temperature detecting means for detecting the temperature of the rectifying means,
The first opening / closing means is energized and the second opening / closing means is shut off when the temperature detected by the temperature detecting means becomes higher than an upper limit temperature. The vehicle-mounted power supply device according to any one of 17.

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