JP4771928B2 - Power supply - Google Patents

Description

  The present invention is charged by a low-voltage battery (for example, a lead storage battery) that is charged by electric power generated by an on-vehicle generator and supplies electric power to an electric load group, and is charged by a voltage obtained by boosting the generated voltage of the on-vehicle generator. The present invention relates to a power supply device including a high-voltage battery (for example, a lithium ion secondary battery) that supplies power to a plurality of other electric loads.

The number of electric loads mounted on a vehicle tends to increase year by year, and large-capacity electric loads are adopted. A lithium ion secondary battery (hereinafter referred to as a lithium battery) that can be charged and discharged at a higher voltage than a lead-acid battery in a conventional power supply device equipped with a lead-acid battery in response to such an increase in electric load and an increase in capacity. In addition, a power supply device has been proposed in which a boosting unit that boosts the power generation voltage of the on-vehicle generator is added.
This power supply device charges the lithium battery with the voltage boosted by the boosting means, and supplies the electric load with a higher voltage than the power output from the lead acid battery.

By the way, the lithium battery has a problem in that when it is left for a long time at a deep charge depth (SOC: State Of Charge), the deterioration proceeds and the chargeable capacity decreases.
In order to solve this problem, there has been proposed a method of forcibly discharging a lithium battery when the lithium battery is left for a long time at a deep charging depth (see Patent Document 1).
JP 2000-287372 A

However, the apparatus disclosed in Patent Document 1 consumes the power of the lithium battery to be discharged almost meaninglessly by supplying it to the motor of the cooling fan.
By the way, unlike a lithium battery that deteriorates when left for a long time at a deep charge depth, a lead storage battery has a problem that it deteriorates when it is over-discharged.
However, Patent Document 1 does not mention means for simultaneously solving the problems of both the lithium battery and the lead storage battery.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to supply a low-voltage first battery to a high-voltage second battery via a step-down means when the engine is stopped. By providing the power supply from the power supply, it is an object of the present invention to provide a power supply device that can suppress deterioration of both the first battery and the second battery without wasting power charged in the second battery.

  Another object of the present invention is to supply the first battery from the second battery while the vehicle is parked without deteriorating the usability of the first battery while driving the vehicle, by maintaining the charging depth of the first battery within a predetermined range. An object of the present invention is to provide a power supply device in which the first battery can accept the generated power.

  Another object of the present invention is to supply power from the second battery to the first battery when the charging depth of the second battery is deep, and to stop supplying power when the charging depth of the second battery becomes shallow. Accordingly, an object of the present invention is to provide a power supply device capable of adjusting the charging depth of the second battery to an appropriate charging depth.

  Still another object of the present invention is to stop power feeding when the charging depth of the first battery becomes deeper due to power feeding from the second battery, and further to resume power feeding after a predetermined time. An object of the present invention is to provide a power supply device capable of suppressing both overcharge and overdischarge of a battery.

A power supply apparatus according to a first aspect of the present invention includes an in-vehicle generator that generates power in conjunction with an engine, a first battery that is charged by electric power generated by the in-vehicle generator and supplies electric power to the electric load group, and the in-vehicle generator There a variable pressure means for boosting the generated electric voltage and / or voltage of the first battery is outputted, said variable pressure means is charged by the voltage boosted, 1 or 2 for supplying power to a plurality of other electrical loads in the power supply device and a battery, said transformer means, switching the step-up operation and step-down operation of the voltage, as well as operation and switching of inoperative Yes to be configured, if the engine is stopped, the second means for switching the variable pressure means to steps down voltage battery has output supplied to the first battery to the step-down operation, if said means is switched, the state of charge of the first battery, full charge A state of charge determination means for determining whether or not deep predetermined charging depth deeper than the depth of charge shallower predetermined range, if the charging depth determination means determines that the a predetermined charging depth deeper, said transformer means Means for switching to step-up operation and non-operation, means for starting timing when the means is switched, and means for switching the voltage-transforming means to step-down operation and operation when the means measures a predetermined time. It is characterized by.

A power supply apparatus according to a second aspect of the present invention is a power generation control means for controlling the voltage value of the power generated by the on-vehicle generator, a first voltage detection means for detecting a voltage value of the first battery, and / or the first. A first current detecting means for detecting a current value flowing into and out of the battery; and a detection result of the first battery obtained based on a detection result of the first voltage detection means and / or a detection result of the first current detection means. state of charge, the a charge range determining means for determining whether the state of charge of a predetermined range, the charging range determining means, when the Most determined depth than the charging depth of the predetermined range, the power generation control means has means to lower than the detection result of the voltage value of the generated power of the vehicle generator of the first voltage detecting unit, when the charge range determining means, intended judged shallow than the charging depth of the predetermined range , Said departure Control means, characterized in that it comprises means to be higher than a detection result of said vehicle generator of the first voltage detecting means a voltage value of the generated power.

According to a third aspect of the present invention, there is provided a power supply device comprising: a second voltage detecting means for detecting a voltage value of the second battery; and / or a second current detecting means for detecting a current value flowing into and out of the second battery; Whether the charging depth of the second battery obtained based on the detection result of the second voltage detection unit and / or the detection result of the second current detection unit is deeper than the first charging depth when the engine is stopped First determination means for determining whether or not, second determination means for determining whether or not the charging depth of the second battery is shallower than the second charging depth, and the first determination means are the first charging depth. If it is determined that the deeper, a means for switching the variable pressure means to step-down operation, after switching the said means, when the second determination means has determined that the said second charge depth shallower than the varying pressure hand to switch the means to step-up operation Characterized Rukoto with and.

In the first invention, if the engine is stopped, by the variable pressure means may switch to the step-down operation, the first battery side through the variable pressure means is fed from the second battery side.
The case where the engine is stopped is a case where the vehicle is not driven, and the first battery and the second battery may be left for a long time. In addition, since the in-vehicle generator that generates power in conjunction with the engine stops power generation when the engine is stopped, the first battery is not charged by the electric power generated by the in-vehicle generator, Discharge gradually due to dark current, self-discharge, etc. caused by power supply.

In order to suppress deterioration of the first battery that deteriorates due to overdischarge and the second battery that deteriorates when left for a long time at a deep charge depth, power is supplied from the second battery to the first battery.
The electric power charged in the first battery in this way is fed from the first battery to the electric load group and is effectively used. The power charged in the first battery, varying pressure through the unit, there is also fed to one or more other electrical loads effectively utilized the fact. That is, the power discharged from the second battery is not wasted.

Here, the second battery, the power of the high voltage is varying pressure means power was boosted low voltage vehicle generator is generating is charged. On the other hand, the first battery is charged with low-voltage power. Since between the first battery and the second battery has a voltage difference, the power of the low voltage supplied from the second battery from being stepped down by varying pressure means is switched to the step-down operation, it is supplied to the first battery The In this case, because the boosting operation stopped, never second battery is powered from the first battery side is charged.

In the second invention, when the engine is operating, the charging from the in-vehicle generator for the first battery is controlled to maintain the charging depth of the first battery within a predetermined range.
If the charging depth of the first battery when the engine is operating is too deep, the first battery cannot accept the power supplied from the second battery when the engine is stopped, and the second battery The electric power that cannot be discharged or discharged from the second battery is wasted.
In addition, if the charging depth of the first battery is too shallow when the engine is operating, it is difficult to supply power from the first battery to the electric load, and deterioration of the first battery due to overdischarge is difficult. Sometimes it goes.

  In order to suppress the above problems, when the charging depth of the first battery is deeper than the charging depth in a predetermined range shallower than the full charge, the power generation control means sets the voltage value of the generated power of the in-vehicle generator to the first voltage. The charging of the first battery is limited by making it lower than the detection result of the detecting means (that is, the voltage value of the first battery). On the other hand, when the charging depth of the first battery is shallower than the charging depth in a predetermined range shallower than full charging, the power generation control means makes the voltage value of the generated power of the on-vehicle generator higher than the detection result of the first voltage detecting means. Thus, the first battery is actively charged.

  Here, the charging depth of the first battery is the detection result of the first voltage detection means and / or the detection result of the first current detection means (that is, the current value flowing into and out of the first battery. Specifically, The charging range determination means determines whether or not the determined charging depth of the first battery is a predetermined range of charging depth.

In the third invention, when the engine is stopped, the charging depth of the second battery is adjusted to an appropriate charging depth.
Therefore, the second battery when it is first charged depth deeper, Ete switch the variable pressure means to buck operation, power to the first battery from the second battery to be supplied. As a result, the second battery having a deep charge depth is discharged.
On the other hand, when the second battery shallower than the first charging depth, because it does not switch the variable pressure means to buck operation, no power is supplied to the first battery from the second battery having a sufficiently shallow depth of charge.

Then, after switching the variable pressure means to buck operation, that is after to be powered for the first battery from the second battery, if the second battery is a second charging depth shallower than is the variable pressure means by switch between the step-up operation, the power to the first battery from the second battery having a sufficiently shallow depth of charge to not be supplied.
On the other hand, the second battery when deeper than the second state of charge is, because it does not switch the variable pressure means boosting operation, power is supplied to the first battery from the second battery. As a result, the second battery still having a relatively deep charge depth is discharged.

  Here, the charging depth of the second battery flows into and out of the detection result of the second voltage detection means (that is, the voltage value of the second battery) and / or the detection result of the second current detection means (that is, the second battery). Current value (specifically, an integrated value of current flowing into and out of the second battery is desirable). Further, the first determination means determines whether or not the obtained charging depth of the second battery is deeper than the first charging depth, and whether or not the obtained charging depth of the second battery is shallower than the second charging depth. The second determination means determines whether or not.

  As the first charging depth and the second charging depth, it is preferable to use appropriate charging depths when the second battery is left for a long time. Note that in the case of a lithium battery, the problem of overdischarge hardly occurs, and therefore, the first charging depth and the second charging depth may be approximately 0%.

In the first aspect of the present invention, the overcharge of the first battery is further suppressed when the engine is stopped.
For this, the engine is stops, if the second battery is powered for the first battery, i.e. after switching the variable pressure it means to step-down operation, the state of charge of the first battery, predetermined charging If a depth deeper, Ete switch the variable pressure means boosting operation and non-operation, so that no power is exchanged with each other between the second battery and the first battery.

  By the way, when the engine is operating, the charging depth of the first battery is maintained at a charging depth within a predetermined range, but the predetermined charging depth used as a criterion for determination here is more than the charging depth within the predetermined range. It is deeper (for example, a charge depth indicating full charge).

Since the first battery whose charging has been stopped is gradually discharged by dark current, self-discharge, or the like, there is a possibility that the first battery may be over-discharged when left for a long period of time. In addition, even after the charging of the first battery is stopped, when the second battery still has a deep charging depth, the second battery deteriorates due to being left for a long period of time. To suppress the inconvenience as described above, when a predetermined time has elapsed after switching the variable pressure means deactivated, Ete switch the variable pressure means to the step-down operation and operation with respect to the first battery from the second battery Power to be supplied.

Here, the predetermined time used as a criterion for determination is based on the time when the first battery is sufficiently discharged due to dark current, self-discharge, etc., the time when the second battery starts to deteriorate due to being left at a deep charging depth, and the like. Are set in advance.
Further, the charge depth determination means determines whether or not the charge depth of the first battery is deeper than a predetermined charge depth based on the detection result of the first voltage detection means and / or the detection result of the first current detection means.

According to the power supply device of the first invention, when the first battery and the second battery are likely to be left for a long time, the power discharged from the second battery can be charged to the first battery.
As a result, since the electric power charged in the second battery can be supplied to various electric loads via the first battery, useless discharge of the electric power charged in the second battery can be suppressed. .
Further, since the second battery that deteriorates when discharged for a long time at a deep charge depth is discharged and the first battery that deteriorates when overdischarged is charged, it is possible to suppress deterioration of both the first battery and the second battery. it can.

In the case of the power supply device according to the second aspect of the invention, the first battery can sufficiently receive the electric power supplied from the second battery while the vehicle is parked by maintaining the charging depth of the first battery during driving of the vehicle within a predetermined range. it can. For this reason, it can be suppressed that the second battery is sufficiently discharged and the electric power discharged by the second battery is consumed wastefully.
In addition, during the driving of the vehicle, the necessary power supply from the first battery to the electric load can be sufficiently performed.

In the case of the power supply device according to the third aspect of the invention, when the second battery is deeply charged while the vehicle is parked, power is supplied from the second battery to the first battery. As a result, it is possible to suppress the second battery from being left for a long time at a deep charging depth.
In addition, when the charging depth of the second battery becomes shallow due to power feeding from the second battery while the vehicle is parked to the first battery, power feeding to the first battery is stopped.

Furthermore, in the case of the power supply device according to the first aspect of the present invention, when the charging depth of the first battery becomes deeper due to power feeding from the second battery while the vehicle is parked, power feeding to the first battery is stopped. As a result, overcharge of the first battery can be suppressed.
In addition, when a predetermined time has elapsed since the power supply to the first battery is stopped from the second battery parked in the vehicle, power is supplied from the second battery to the first battery. As a result, overdischarge of the first battery and long-time leaving of the second battery at a deep charging depth can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

FIG. 1 is a block diagram showing a configuration of a power supply device 1 according to an embodiment of the present invention.
The power supply device 1 is mounted on a vehicle including an engine E, and includes a lead storage battery (first battery) 11, a lithium battery (second battery) 12, and a DC / DC converter ( transformer means; hereinafter, step-up means or step-down means). ( Also referred to as means) 13 and an alternator (on-vehicle generator) 14.
The power supply device 1 includes a first voltage sensor (first voltage detection means) 51, a second voltage sensor (second voltage detection means) 52, a first current sensor (first current detection means) 61, And a two-current sensor (second current detection means) 62.

  Furthermore, the power supply apparatus 1 includes a first control unit 21 and a second control unit 22 each using a microcomputer, and the first control unit 21 includes an alternator 14, a second control unit 22, a first voltage sensor 51, The second control unit 22 is connected to the first current sensor 61 and the engine E through a signal line. The second control unit 22 includes the DC / DC converter 13, the first control unit 21, the second voltage sensor 52, and the second current sensor 62. Connected with signal lines.

  The first control unit 21 mainly performs control related to charging / discharging of the lead storage battery 11. The second control unit 22 mainly performs control related to charging / discharging of the lithium battery 12. A signal (for example, a rotation speed signal) indicating whether the engine E is operating or stopped is given from the engine E to the first control unit 21 and also given to the second control unit 22 via the first control unit 21. It is done. The 1st control part 21 and the 2nd control part 22 judge the operation / stop of engine E based on whether this signal is given. As described above, various signals (for example, a full charge signal described later) are output from the first control unit 21 to the second control unit 22.

The high-voltage side terminal of the lead storage battery 11 is connected to the low-voltage side terminal of the DC / DC converter 13, and is further connected to the alternator 14 and the loads 41, 41,. Moreover, the low voltage | pressure side terminal of the lead storage battery 11 is connected to the ground terminal.
Here, the loads 41, 41,... Are a low voltage electric load group such as a vehicle lamp. Moreover, the 1st control part 21, the 2nd control part 22, etc. are also contained in an electrical load group.
On the other hand, the high voltage side terminal of the lithium battery 12 is connected to the high voltage side terminal of the DC / DC converter 13, and is further connected to an electric motor 42, which is an electric load, via a motor driver 43. The low voltage side terminal of the lithium battery 12 is connected to the ground terminal. The high voltage side terminal of the lithium battery 12 may be connected to a plurality of electric loads including the electric motor 42.

The DC / DC converter 13 as the boosting means boosts the low voltage (specifically, about 14V) power on the lead storage battery 11 side including the power generated by the alternator 14 to a high voltage (specifically, about 42V). To the lithium battery 12 side (in FIG. 1, white arrow direction). Further, the DC / DC converter 13 as the step-down means steps down the power of about 42 V on the lithium battery 12 side to about 14 V and gives it to the lead storage battery 11 side (the arrow direction indicated by the two-dot chain line in FIG. 1). .
The step-up operation and the step-down operation of the DC / DC converter 13 are executed exclusively, and switching between the step-up operation and the step-down operation is controlled by the second control unit 22.
The second control unit 22 also controls the output voltage and output current of the DC / DC converter 13.

  The alternator 14 is an AC on-vehicle generator that generates power in conjunction with the engine E, starts power generation in conjunction with the operation of the engine E, and stops power generation in conjunction with the stop of the engine E. In the alternator 14 of the present embodiment, the voltage value of the generated power is higher than about 14 V which is the charging voltage of the lead storage battery 11 and lower than the discharge voltage of the lead storage battery 11 and higher than 0 V (that is, the power generation stopped state). The voltage value can be switched to at least two stages. The first control unit 21 controls switching of the voltage value of the generated power of the alternator 14 between high and low.

  The lead storage battery 11 is charged with the applied electric power of about 14 V and supplies electric power to each of the plurality of loads 41, 41,... As an electric load group. However, the load 41, 41,... May be supplied with about 14 V of power generated and rectified by the alternator 14 or with about 14 V reduced by the DC / DC converter 13.

The lead storage battery 11 is supplied with approximately 14 V of power generated and rectified by the alternator 14. That is, the first control unit 21 controls the charge / discharge of the lead storage battery 11 by controlling the voltage value of the generated power of the alternator 14.
Further, the lead storage battery 11 may be supplied with electric power that is stepped down to about 14 V by the DC / DC converter 13.

The lithium battery 12 is charged with the supplied electric power of about 42 V and supplies electric power to the electric motor 42 via the motor driver 43. However, the electric motor 42 may be supplied with electric power boosted to about 42 V by the DC / DC converter 13 via the motor driver 43.
The motor driver 43 converts the direct current supplied from the power supply device 1 into an alternating current and supplies the alternating current to the electric motor 42.

  The lithium battery 12 is supplied with electric power generated by an alternator 14 and boosted to about 42 V by a DC / DC converter 13. Further, the low voltage power output from the lead storage battery 11 may be boosted to about 42 V by the DC / DC converter 13 and supplied to the lithium battery 12.

Here, when low-voltage power is boosted and applied to the lithium battery 12 side, the lithium battery 12 is charged. Conversely, when high voltage power is stepped down and applied to the lead storage battery 11 side, the lithium battery 12 is discharged.
That is, the second control unit 22 performs control related to charging / discharging of the lithium battery 12 by switching between the step-up operation and the step-down operation of the DC / DC converter 13.

The first voltage sensor 51 detects the voltage value of the lead storage battery 11 and supplies it to the first control unit 21, and the first current sensor 61 detects the current value flowing into and out of the lead storage battery 11, 1 is given to the control unit 21.
The second voltage sensor 52 detects the voltage value of the lithium battery 12 and supplies it to the second control unit 22, and the second current sensor 62 detects the current value flowing into and out of the lithium battery 12, 2 is given to the control unit 22.
Hereinafter, the current value in the outflow (discharge) direction is a positive value, and the current value in the inflow (charge) direction is a negative value.

By the way, the lead storage battery 11 deteriorates when it is overdischarged, and the lithium battery 12 deteriorates when left for a long time at a deep charge depth, and the rechargeable capacity decreases.
For this reason, in the power supply device 1 of this Embodiment, before leaving the lead storage battery 11 and the lithium battery 12 for a long time, the lithium battery 12 is discharged, and also the lead storage battery 11 is charged. Then, the power discharged from the lithium battery 12 is used as the power to charge the lead storage battery 11.

However, if the lead storage battery 11 is substantially fully charged at the start of discharge of the lithium battery 12, the lead storage battery 11 cannot accept the power discharged from the lithium battery 12, and if it is accepted, it is overcharged. A malfunction occurs. On the contrary, if the lead storage battery 11 is largely discharged before the start of the discharge of the lithium battery 12, the power discharged from the lithium battery 12 is accepted, but power supply from the lead storage battery 11 to the loads 41, 41,. There is a problem that it is not performed sufficiently.
In order to suppress the above problems, the charge depth of the lead storage battery 11 is maintained at a charge depth within a predetermined range shallower than the charge depth indicating full charge.

Here, the charging depth of the lead storage battery 11 is calculated by the first control unit 21 based on the detection result of the first voltage sensor 51 and / or the detection result of the first current sensor 61. Specifically, the charge depth of the lead storage battery 11 is calculated based on the integrated value of the detection result of the first current sensor 61 (that is, the integrated value of the charge / discharge current of the lead storage battery 11). That is, assuming that the charging capacity of the fully charged lead storage battery 11 is A ₀ and the integrated value of the charge / discharge current of the lead storage battery 11 from the fully charged state is A, the charging depth of the lead storage battery 11 = (A ₀ −A) / A ₀ × 100 [%].
For this reason, in this embodiment, the integrated value A of the charge / discharge current of the lead storage battery 11 (that is, the integrated value A of the detection result of the first current sensor 61) is used as a parameter indicating the charging depth of the lead storage battery 11.

The minimum depth of the state of charge of a predetermined range of the aforementioned (predetermined SOC range of FIG. 2 to be described later) (hereinafter, referred to as the shallowest depth of charge) the integrated value indicating the shallowest integrated value A _1, the predetermined range of the aforementioned integrated value indicating the maximum depth of the state of charge (hereinafter, referred to as the deepest depth of charge) and deepest integrated value a ₂ a. However, the shallowest charge depth [%] <the deepest charge depth [%] and the shallowest integrated value A ₁ > the deepest integrated value A ₂ , and the integrated value A is maintained in the range of A ₂ ≦ A ≦ A _1. Is done.
The shallowest integrated value A ₁ corresponds to a charging depth at which power is sufficiently supplied from the lead storage battery 11 to the loads 41, 41,..., And the deepest integrated value A ₂ is the electric power supplied from the lithium battery 12. 11 corresponds to a fully acceptable charge depth.

  On the other hand, the charging depth of the lithium battery 12 is calculated based on the detection result of the second voltage sensor 52 and / or the detection result of the second current sensor 62. Since the charging depth of the lithium battery 12 corresponds to the detection result of the second voltage sensor 52 (that is, the voltage value of the lithium battery 12), in the present embodiment, the lithium battery 12 is used as a parameter indicating the charging depth of the lithium battery 12. Voltage value V (that is, the detection result V of the second voltage sensor 52) is used.

When the charging depth is sufficiently shallow, there is no problem even if the lithium battery 12 is left for a long time. Therefore, when the charging depth is deeper than the predetermined first charging depth, the lithium battery 12 is transferred to the lead storage battery 11. Supply power.
Then, by supplying power from the lithium battery 12 to the lead storage battery 11, the power from the lithium battery 12 to the lead storage battery 11 when the charging depth of the lithium battery 12 becomes shallower than a predetermined second charging depth is sufficiently shallow. Stop supplying.

Hereinafter, the voltage value of the lithium battery 12 corresponding to the first charging depth is referred to as a first voltage value V _1, and the voltage value of the lithium battery 12 corresponding to the second charging depth is referred to as a second voltage value V ₂ .
It is desirable that the first voltage value V ₁ and the second voltage value V ₂ are sufficiently small voltage values of V ₁ ≧ V ₂ . If the first voltage value V ₁ and the second voltage value V ₂ are too large, the lithium battery 12 is not sufficiently discharged and the lithium battery 12 deteriorates.

FIG. 2 is a characteristic diagram showing the change over time in the charge depth of the lead storage battery 11, and FIG. 3 is a characteristic diagram showing the change over time in the charge depth of the lithium battery 12.
The horizontal axis in FIG. 2 indicates the time elapsed from the start of operation of the engine E, and the horizontal axis in FIG. Moreover, the vertical axis | shaft of FIG. 2 has shown the charge depth of the lead storage battery 11, and the vertical axis | shaft of FIG.
The unit of the charge depth is [%], where 0% indicates the charge depth in a fully discharged state, and 100% indicates the fully charged charge depth.

  As shown in FIG. 2, the electric power generated by the alternator 14 is charged into the lead storage battery 11 from the start of driving of the vehicle, that is, the operation of the engine E, and the charge depth of the lead storage battery 11 is deepened (that is, the lead storage battery). 11 and the integrated value A of the charge / discharge current decreases). At this time, in order to charge the lead storage battery 11 efficiently, the voltage value of the generated power of the alternator 14 is kept high.

  When the lead storage battery 11 reaches full charge, the voltage value of the generated power of the alternator 14 is kept low in order to protect the lead storage battery 11 from overcharging. While the voltage value of the power generated by the alternator 14 is low, the lead storage battery 11 is hardly charged from the alternator 14, and the lead storage battery 11 and the alternator 14 supply power to the loads 41, 41,. Therefore, the lead storage battery 11 is discharged, and the charge depth of the lead storage battery 11 becomes shallow (that is, the integrated value A of the charge / discharge current of the lead storage battery 11 increases).

Then, the state of charge of the lead-acid battery 11 by the discharge of the lead-acid battery 11 has become shallower than the shallowest depth of charge predetermined SOC range (i.e. the integrated value A is exceeded shallowest integrated value A ₁₎ time, the alternator 14 The voltage value of the generated power is kept high, and the lead storage battery 11 is charged. Next, when the charging depth of the lead storage battery 11 becomes deeper than the deepest charging depth in the predetermined SOC range by charging the lead storage battery 11 (that is, the integrated value A is lower than the deepest integrated value A ₂ ), the power generation of the alternator 14 is performed. The voltage value of electric power is kept low, and the lead storage battery 11 is discharged.
In this way, the charging depth (that is, the integrated value A) of the lead storage battery 11 is maintained within the predetermined SOC range (that is, the range of A ₂ ≦ A ≦ A ₁ ).

As shown in FIGS. 2 and 3, the power generation of the alternator 14 is stopped when the vehicle is parked, that is, when the engine E is stopped. At this time, the charging depth of the lithium battery 12 is set to the first voltage value V ₁ . If it is deeper than the corresponding charging depth, instead of the electric power generated by the alternator 14, the electric power discharged from the lithium battery 12 is charged into the lead storage battery 11, the charging depth of the lead storage battery 11 is increased, and the lithium battery 12 is charged. The depth becomes shallow (that is, the voltage value V decreases).

When the lead storage battery 11 reaches full charge, power supply from the lithium battery 12 to the lead storage battery 11 is stopped in order to protect the lead storage battery 11 from overcharging. In this case, the lead storage battery 11 is not charged, and the charging depth gradually decreases due to dark current, self-discharge, or the like.
On the other hand, the lithium battery 12 gradually becomes shallower in charging depth due to dark current, self-discharge, etc., but the degree of reduction (that is, the degree of reduction) is less than the degree of reduction when the lead storage battery 11 is fed. Is also small.

When the predetermined time T ₀ has elapsed from the time when the power supply from the lithium battery 12 to the lead storage battery 11 is stopped, the charging depth of the lead storage battery 11 can accept the power supply from the lithium battery 12 again due to dark current, self-discharge, etc. Shallow to the depth of charge. For this reason, the electric power discharged from the lithium battery 12 is again charged in the lead storage battery 11, the charge depth of the lead storage battery 11 is increased, and the charge depth of the lithium battery 12 is decreased.
Finally, when the state of charge of the lithium battery 12 becomes charged depth shallower than that corresponding to the second voltage value V _2, power supply to the lead-acid battery 11 is stopped from the lithium battery 12.

4 and 5 are flowcharts showing the procedure of the lead storage battery control process executed by the first control unit 21. The lead storage battery control process is executed when the engine E is operating. As the operation of the engine E starts, the alternator 14 starts generating power regardless of the control of the first control unit 21.
First, the first control unit 21 controls the alternator 14 so that the voltage value of the generated power of the alternator 14 is kept higher than the detection result of the first voltage sensor 51 (S11).

Next, the 1st control part 21 calculates the charge depth of the lead storage battery 11 (S12), and determines whether the calculation result in S12 is the charge depth which shows a full charge (S13).
When the calculation result in S12 is not the charge depth indicating full charge (NO in S13), that is, when the lead storage battery 11 is not yet fully charged, the first control unit 21 returns the process to S12.

  When the calculation result in S12 is the charge depth indicating full charge (YES in S13), that is, when the lead storage battery 11 is fully charged, the first control unit 21 determines that the voltage value of the generated power of the alternator 14 is first. The alternator 14 is controlled so as to be kept lower than the detection result of the one voltage sensor 51 (S14).

Next, the first control unit 21 calculates the integrated value A of the charge / discharge current of the lead storage battery 11 from the fully charged state (S15).
The first controller 21 determines that the integrated value A as a calculation result in S15, whether above the shallowest integrated value A ₁ (S16).
When A> A ₁ (YES in S16), since the charging depth is too shallow, the first control unit 21 determines that the voltage value of the generated power of the alternator 14 is the first voltage sensor. The alternator 14 is controlled so as to be kept higher than the detection result 51 (S19), and the process returns to S15. In this case, the lead storage battery 11 whose charging depth has become too shallow is charged from the alternator 14.

When A ≦ A ₁ (NO in S16), the first control unit 21 determines whether or not the integrated value A as the calculation result in S15 is less than the deepest integrated value A ₂ (S17).
When A <A ₂ (YES in S17), since the charging depth is too deep, the first control unit 21 returns the process to S14, and the voltage value of the generated power of the alternator 14 is the first voltage sensor 51. The alternator 14 is controlled so as to be kept lower than the detection result. In this case, the lead storage battery 11 whose charging depth has become too deep is discharged.

When A ≧ A ₂ (NO in S17), since the charging depth of the lead storage battery 11 is maintained within the predetermined SOC range, the first control unit 21 determines whether or not the engine E has stopped (S18). ) If not stopped (NO in S18), the process returns to S15.
When the engine E is stopped (YES in S18), the alternator 14 stops the power generation regardless of the control of the first control unit 21 with the operation stop of the engine E, and the first control unit 21 performs the process of S15. Similarly, the integrated value A is calculated (S21). Next, the first control unit 21 determines whether or not the integrated value A as the calculation result in S21 is an integrated value indicating full charge (that is, the charge capacity A _{0 of the} fully charged lead storage battery 11) (S22). ).

When the calculation result in S21 is not an integrated value indicating full charge (NO in S22), that is, when the lead storage battery 11 is not yet fully charged, the first control unit 21 determines whether or not the engine E has operated. (S23), if the engine E is not operating (NO in S23), the process returns to S21.
When engine E operates (YES in S23), first control unit 21 returns the process to S11.

When the calculation result in S21 is an integrated value indicating full charge (YES in S22), that is, when the lead storage battery 11 is fully charged, the first control unit 21 sends the second control unit 22 to the lead storage battery 11. A full charge signal indicating that is fully charged is output (S24), and the process returns to S21. In this case, the lead storage battery 11 is not supplied with power from the lithium battery 12 and is discharged by dark current, self-discharge, or the like. However, when the charging time of the lead storage battery 11 becomes moderately shallow after a lapse of the predetermined time T ₀ , power is again supplied from the lithium battery 12 and the lead storage battery 11 is charged.

6 and 7 are flowcharts showing the procedure of the lithium battery control process executed by the second control unit 22. The lithium battery control process is executed when the engine E is operating, and the DC / DC converter 13 is switched to the boost side by the second control unit 22. With the start of operation of engine E, alternator 14 starts power generation, and lithium battery 12 is charged with high voltage power obtained by boosting DC / DC converter 13 with low voltage power generated by alternator 14.
The second control unit 22 determines whether or not the engine E has stopped (S31), and if not stopped (NO in S31), repeats the process of S31.

When the engine E stops (YES in S31), the alternator 14 stops generating power as the operation of the engine E stops, and the charging of the lithium battery 12 from the alternator 14 stops.
Here, the second control unit 22 detects the voltage value V of the lithium battery 12 (S32), the voltage value V as a detection result of S32, determines whether a first voltage value V ₁ or more (S33).

When V <V ₁ (NO in S33), the charging depth of the lithium battery 12 is sufficiently shallow, and therefore the second control unit 22 moves the process to S52 described later without executing the process after S34.
When V ≧ V ₁ (YES in S33), since the charging depth of the lithium battery 12 is deep, the second control unit 22 switches the DC / DC converter 13 to the step-down side (S34). In this case, low voltage power obtained by stepping down the high voltage power supplied from the lithium battery 12 by the DC / DC converter 13 is supplied to the lead storage battery 11, and the lead storage battery 11 is charged.

Then, the second control unit 22 detects the voltage value V of the lithium battery 12 (S35), the voltage value V as a detection result of S35, determines whether or not the second voltage value V ₂ less ( S36).
When V> V ₂ (NO in S36), the charging depth of the lithium battery 12 is still sufficiently deep, so the second control unit 22 receives a full charge signal indicating that the lead storage battery 11 is fully charged. It is determined whether or not (S41).
If the full charge signal has not been input (NO in S41), the lead storage battery 11 can still receive power sufficiently, and the second control unit 22 returns the process to S35. For this reason, the lithium battery 12 continues to be discharged, and the lead storage battery 11 continues to be charged.

  When the full charge signal is input (YES in S41), since the lead storage battery 11 has not already received power, the second control unit 22 switches the DC / DC converter 13 to the boost side (S42). In this case, since the high voltage power supplied from the lithium battery 12 is not stepped down by the DC / DC converter 13, the lithium battery 12 is not discharged and the lead storage battery 11 is not charged.

After the processing of S42 is completed, the second control unit 22 starts counting elapsed time using a timer (not shown) (S43), and charges the lead storage battery 11 until the charging depth at which power from the lithium battery 12 can be accepted again. It is determined whether or not a predetermined time T ₀ when the depth becomes shallower has passed (S44).
If the predetermined time T ₀ has not elapsed (NO in S44), the lead storage battery 11 has not yet received power, so the second control unit 22 repeats the process of S44. For this reason, the lithium battery 12 is not discharged and the lead storage battery 11 is not charged.

When the predetermined time T ₀ has elapsed (YES in S44), since the lead storage battery 11 has already been able to accept power, the second control unit 22 moves the process to S34 and switches the DC / DC converter 13 to the step-down side. . In this case, low voltage power obtained by stepping down the high voltage power supplied from the lithium battery 12 by the DC / DC converter 13 is supplied to the lead storage battery 11, and the lead storage battery 11 is charged.

On the other hand, when V ≦ V ₂ (YES in S36), since the lithium battery 12 has been sufficiently discharged, the second control unit 22 switches the DC / DC converter 13 to the boost side (S51). In this case, since the high voltage power supplied from the lithium battery 12 is not stepped down by the DC / DC converter 13, the lithium battery 12 is not discharged and the lead storage battery 11 is not charged.

After the completion of the process of S51 or when NO in S33, the second control unit 22 determines whether or not the engine E is operated (S52). When the engine E is not operated (NO in S52), The process of S52 is repeated. In this case, the lead storage battery 11 and the lithium battery 12 are gradually discharged by dark current, self-discharge, or the like.
When engine E operates (YES in S52), second control unit 22 returns the process to S31.

  In the power supply device 1 as described above, even if the vehicle is stopped and the lead storage battery 11 and the lithium battery 12 are left unattended for a long time, the lithium battery 12 is discharged and the discharged power is charged into the lead storage battery 11. The deterioration of both the lead storage battery 11 and the lithium battery 12 is suppressed simultaneously. Moreover, since the power once charged in the lithium battery 12 is transferred to the lead storage battery 11 and is effectively consumed by the loads 41, 41,..., Waste of the charged power is suppressed.

It is a block diagram which shows the structure of the power supply device which concerns on embodiment of this invention. It is a characteristic view which shows the time change of the charge depth of the lead acid battery as a 1st battery with which the power supply device which concerns on embodiment of this invention is equipped. It is a characteristic view which shows the time change of the charge depth of the lithium battery as a 2nd battery with which the power supply device which concerns on embodiment of this invention is provided. It is a flowchart which shows the procedure of the lead storage battery control process which the 1st control part of the power supply device which concerns on embodiment of this invention performs. It is a flowchart which shows the procedure of the lead storage battery control process which the 1st control part of the power supply device which concerns on embodiment of this invention performs. It is a flowchart which shows the procedure of the lithium battery control process which the 2nd control part of the power supply device which concerns on embodiment of this invention performs. It is a flowchart which shows the procedure of the lithium battery control process which the 2nd control part of the power supply device which concerns on embodiment of this invention performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply device 11 Lead acid battery (1st battery)
12 Lithium battery (second battery)
13 DC / DC converter (strange圧手stage)
14 Alternator (in-vehicle generator)
21 1st control part (power generation control means, charge range determination means, charge depth determination means)
22 2nd control part (1st determination means, 2nd determination means)
41 Load (electric load group)
42 Electric motor (electric load)
51 1st voltage sensor (1st voltage detection means)
52 Second voltage sensor (second voltage detection means)
61 First current sensor (first current detection means)
62 2nd current sensor (2nd current detection means)
E engine

Claims (3)

An in-vehicle generator that generates power in conjunction with the engine;
A first battery charged with electric power generated by the in-vehicle generator and supplying electric power to the electric load group;
A variable pressure means for the vehicle generator is to boost the voltage of power generation and / or voltage, wherein the first battery and outputs,
The variable pressure means is charged by the voltage boosted the power supply apparatus and a second battery for supplying power to one or more other electrical loads,
The transformer means is configured to be capable of switching between voltage step-up operation and step-down operation, and switching between operation and non-operation,
Means for switching if the engine has stopped, the variable pressure means to steps down the voltage to the second battery has output supplied to the first battery to the step-down operation,
A charging depth determination means for determining whether or not the charging depth of the first battery is greater than or equal to a predetermined charging depth deeper than a charging depth in a predetermined range shallower than full charging when the means is switched ;
A means for switching the voltage transforming means to a step-up operation and a non-operation when the charge depth determination means determines that it is deeper than the predetermined charge depth;
Means for starting timing when the means switches;
Means for switching the voltage transforming means to step-down operation and operation when the means counts a predetermined time;
Power supply, characterized in that it comprises a. Power generation control means for controlling the voltage level of the generated power of the on-vehicle generator; and
First voltage detection means for detecting a voltage value of the first battery and / or first current detection means for detecting a current value flowing into and out of the first battery;
The detection result and / or state of charge of the first battery is determined based on a detection result of the first current detection means of the first voltage detecting means, the charging is determined whether the a predetermined range of charge A range determination means, and
The charging range judging means, if the intended determined depth than the charging depth of the predetermined range, the power generation control means lower than the detection result of the first voltage detecting means a voltage value of the generated power of the vehicle generator Having means,
The charge range determining means, when it is the intention determination shallow than the charging depth of the predetermined range, the power generation control means is set higher than the detection result of the first voltage detecting means a voltage value of the generated power of the vehicle generator The power supply apparatus according to claim 1, further comprising: means. Second voltage detection means for detecting a voltage value of the second battery and / or second current detection means for detecting a current value flowing into and out of the second battery;
When the engine is stopped, the charging depth of the second battery obtained based on the detection result of the second voltage detection means and / or the detection result of the second current detection means is deeper than the first charging depth. First determination means for determining whether or not,
Second determination means for determining whether or not the charging depth of the second battery is shallower than the second charging depth ;
When the first determination means has determined that the first state of charge or deeper, and means for switching the variable pressure means to the step-down operation,
After switching said means, said second determination means, when it is determined that the second state of charge shallower, and means for switching the variable pressure means boosting operation
The power supply device according to claim 1 or 2, characterized in Rukoto equipped with.

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