JP2020038782A - Power supply controller - Google Patents

Abstract

To provide a technique capable of suppressing an electric load from having a power supply defect when a plurality of storage batteries are used to supply electric power to the electric load.SOLUTION: A power supply controller 10 can drive an electric load with a first storage battery 51 and a second storage battery 52. The power supply controller comprises a temperature acquisition part, a switching determination part, a temperature determination part, and a storage battery switching part. The storage battery switching part outputs, when switching the drive battery, a switching signal after outputting a superposition signal. The superposition signal short-circuits the first storage battery and electric load to each other and also short-circuits the second storage battery and electric load to each other. The switching signal releases one storage battery and the electric load from each other and also short-circuits the other storage battery and electric load to each other. Here, the power supply controller outputs neither the superposition signal nor the switching signal if temperature conditions are not met in switching the drive battery.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a technique for supplying power to an electric load using a plurality of storage batteries.

  Patent Literature 1 proposes a technique in which a power supply device mounted on a vehicle uses a plurality of storage batteries and supplies power to an electric load mounted on the vehicle while properly using each of the storage batteries.

Japanese Patent No. 5488169

  The power supply device described in Patent Literature 1 includes two storage batteries. In the power supply device, the storage batteries are connected in parallel. In addition, each of the storage batteries is connected in series to the electric load, and a switch is provided in each of the connection paths, and these two switches are configured to be short-circuited or opened as appropriate.

  When switching the storage battery that supplies power to the electric load from one of the two storage batteries to the other storage battery, it is desirable that the supply of power to the electric load is not interrupted (hereinafter, also referred to as a power loss). . For example, in a power supply device as described in Patent Literature 1, it is considered that power loss can be suppressed by performing switching after a state in which the two switches are short-circuited together.

  However, in a state in which the two switches are short-circuited, there is a possibility that a failure occurs due to a rise in temperature in each switch due to an increase in current consumption, and a power supply defect may occur in an electric load due to the failure of the switch.

  One aspect of the present disclosure is to provide a technique capable of suppressing occurrence of a power supply defect in an electric load when power is supplied to the electric load using a plurality of storage batteries.

  One aspect of the present disclosure is a power supply control device (10) that can drive an electric load with a plurality of storage batteries. The plurality of storage batteries include a first storage battery (51) and a second storage battery (52). The power supply control device includes a temperature acquisition unit (S10), a switching determination unit (S20), a temperature determination unit (S30, S35), and a storage battery switching unit (S40-S80).

  The temperature acquisition unit is a switch that is switched to either short-circuit or open in accordance with an instruction signal from the power supply control device, a first connection switch that short-circuits or opens between the first storage battery and the electric load, and a second storage battery. The temperature of each of the second connection switches that shorts or opens between the electric loads is acquired.

  The switching determination unit is configured to switch the driving battery that is the storage battery that drives the electric load from the storage battery that is driving the electric load and that is not driving the electric load from one of the first storage battery and the second storage battery. It is determined whether there is a switching request for switching to the other one of the first storage battery and the second storage battery. The temperature determining unit determines whether the temperatures of the first connection switch and the second connection switch each satisfy a predetermined temperature condition.

  When it is determined that there is a switching request and the temperature condition is satisfied, the storage battery switching unit determines in advance at least an instruction signal that is a superimposition signal that short-circuits the first connection switch and short-circuits the second connection switch. And outputs the switching signal after outputting the superimposed signal. The storage battery switching unit does not output the superimposition signal and the switching signal when it is determined that there is a switching request and the temperature condition is not satisfied.

The switching signal is an instruction signal that opens one storage battery and the electric load and short-circuits the other storage battery and the electric load.
As described above, when there is a switching request, the power supply control device outputs the switching signal after outputting the superimposed signal. As a result, when power is supplied to the electric load using the plurality of storage batteries, it is possible to suppress occurrence of a power supply defect in the electric load.

  Further, when there is a switching request, the power supply control device switches only when the temperature of the first connection switch and the temperature of the second connection switch satisfy the temperature condition. That is, when the temperature condition is not satisfied, no superimposed signal for switching is output. For example, the temperature of the first connection switch and the temperature of the second connection switch are appropriately lower than a predetermined temperature. By appropriately setting such temperature conditions, the first connection switch and the second connection switch fail due to temperature rise. Is suppressed.

As a result, when power is supplied to the electric load using the plurality of storage batteries, it is possible to suppress occurrence of a power supply defect in the electric load.
Note that the reference numerals in parentheses described in this column and in the claims indicate a correspondence relationship with specific means described in the embodiment described below as one aspect, and the technical scope of the present disclosure will be described. It is not limited.

FIG. 1 is a block diagram illustrating a configuration of a vehicle power supply system according to a first embodiment. 9 is a flowchart of a switching process according to the first embodiment. FIG. 3 is an explanatory diagram illustrating temperature conditions according to the first embodiment. 9 is a flowchart of overlap time processing. 4 is a timing chart illustrating the operation of the vehicle power supply system according to the first embodiment. Explanatory drawing explaining the state of the vehicle power supply system at time t2. Explanatory drawing explaining the overlap state after time t2. Explanatory drawing explaining the state of the vehicle power supply system at time t3. Explanatory drawing explaining the overlap state after time t6. Explanatory drawing explaining the state of the vehicle power supply system at time t7. FIG. 9 is an explanatory diagram illustrating temperature conditions of Modification Example 1. 9 is a flowchart of a switching process according to a first modification. The figure explaining the connection state in the vehicle power supply system at the time of the deceleration driving | operation of the modification 2. FIG. 4 is a block diagram showing a configuration of a vehicle power supply system according to a second embodiment. 9 is a flowchart of a switching process according to the second embodiment. 9 is a timing chart illustrating the operation of the vehicle power supply system according to the second embodiment. Explanatory drawing explaining the state of the vehicle power supply system at time t11. Explanatory drawing explaining the state of the vehicle power supply system at time t13. Explanatory drawing explaining the overlap state after time t15. Explanatory drawing explaining the state of the vehicle power supply system at time t16.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
[1-1-1. overall structure]
The vehicle power supply system 1 shown in FIG. 1 is a system mounted on a vehicle. The vehicle here runs with an internal combustion engine (hereinafter, engine) as a drive source.

  The vehicle power supply system 1 includes an alternator 41, a starter 33, a first load 31 and a second load 32, which are electric components mounted on a vehicle, a plurality of storage batteries, a first switch 21 (hereinafter, a first switch), It includes a two-connection switch (hereinafter, a second switch) 22 and an electronic control unit (hereinafter, an ECU) 10. The plurality of storage batteries include a lead storage battery 51 and a lithium storage battery 52.

  The starter 33, the first load 31, the second load 32, the lead storage battery 51, and the lithium storage battery 52 are connected in parallel to the alternator 41. The first switch 21 is disposed between the lead storage battery 51 and the second load 32, and the second switch 22 is disposed between the lithium storage battery 52 and the second load 32.

  Each of the first switch 21 and the second switch 22 is a switch that can be switched between short circuit and open in accordance with an instruction signal from the ECU 10. The first switch 21 short-circuits or opens between the lead storage battery 51 and the second load 32. The second switch 22 short-circuits or opens between the lithium storage battery 52 and the second load 32.

  Although not shown, each of the first switch 21 and the second switch 22 is provided with a temperature sensor for measuring a temperature. Each temperature sensor outputs to the ECU 10 a signal indicating the temperature of the first switch 21 and a signal indicating the temperature of the second switch 22.

  The starter 33, the first load 31, and the second load 32 are electrical loads. The starter 33 is a motor that starts the engine. The first load 31 and the second load 32 are electrical components mounted on a vehicle.

  The first load 31 is a general electric load other than the starter 33 and a second load 32 described later. Specifically, the first load 31 may include a headlight, a wiper such as a front windshield, a fan of an air conditioner, a heater for a defroster of a rear windshield, and the like. Further, the first load 31 may include a driving mechanism such as a power steering and a power window.

  The second load 32 is an electric load that is required to have a substantially constant supply power voltage or to have a stable voltage fluctuation within a predetermined range. A lead storage battery 51 can be connected to the second load 32 via the first switch 21, and a lithium storage battery 52 can be connected via the second switch 22. Specifically, the second load 32 may include a vehicle-mounted navigation device, a vehicle-mounted audio device, and the like.

  The alternator 41 generates electric power by rotating energy of a crankshaft. The electric power generated by the alternator 41 can be supplied to the starter 33, the first load 31, the second load 32, the lead storage battery 51, and the lithium storage battery 52.

  Here, the alternator 41 and the lead storage battery 51 are located on the lead storage battery 51 side of the first switch 21 as shown in FIG. That is, the alternator 41 is a charging device that charges at least the lead storage battery 51 regardless of whether the first switch 21 and the second switch 22 are open or short-circuited. On the other hand, with respect to the alternator 41, the lithium storage battery 52 is located on the lithium storage battery 52 side of the first switch 21 and the second switch 22. That is, the alternator 41 is a charging device that charges the lithium storage battery 52 only when the first switch 21 and the second switch 22 are short-circuited.

  When the engine is stopped and power is not being generated by the alternator 41, power can be supplied to the starter 33, the first load 31, and the second load 32 from at least one of the lead storage battery 51 and the lithium storage battery 52.

  Here, the lead storage battery 51 supplies power to the starter 33 and the first load 31 regardless of whether the first switch 21 and the second switch 22 are open or short-circuited. The lead storage battery 51 supplies power to the second load 32 when at least the first switch 21 is short-circuited.

  On the other hand, the lithium storage battery 52 supplies power to the second load 32 when at least the second switch 22 is short-circuited. Further, when both the first switch 21 and the second switch 22 are short-circuited, the lithium storage battery 52 supplies power to the first load 31 and the second load 32.

  When the first switch 21 is short-circuited and the second switch 22 is short-circuited, the storage battery having the higher output voltage among the lead storage battery 51 and the lithium storage battery 52 is switched from the storage battery having the lower output voltage among the lead storage battery 51 and the lithium storage battery 52. Electric power can be supplied in the direction toward the storage battery.

  The lead storage battery 51 is a general-purpose storage battery. The storage capacity of the lead storage battery 51 is set larger than that of the lithium storage battery 52. In the present embodiment, the output voltage when the lead storage battery 51 is fully charged is set higher than the output voltage when the lithium storage battery 52 is fully charged.

  The lithium storage battery 52 is a high-density storage battery that has less power loss during charge and discharge and has a higher output density and energy density than the lead storage battery 51. In the lithium storage battery 52, a plurality of battery cells (not shown) are connected in series.

  The ECU 10 includes a microcomputer having a CPU 11 and a semiconductor memory (hereinafter, a memory 12) such as a RAM or a ROM. Each function of the ECU 10 is realized by the CPU 11 executing a program stored in the memory 12. When this program is executed, a method corresponding to the program is executed. Note that the ECU 10 may include one microcomputer or a plurality of microcomputers.

  The technique for realizing each function of the ECU 10 is not limited to software, and some or all of the functions may be realized using one or a plurality of hardware. For example, when the functions described above are implemented by an electronic circuit that is hardware, the electronic circuit may be implemented by a digital circuit, an analog circuit, or a combination thereof.

  The ECU 10 realizes at least control for enabling the second load 32 to be driven by a plurality of storage batteries such as the lead storage battery 51 and the lithium storage battery 52 by executing a switching process described later.

[1-1-2. Supply of power to second load]
In the vehicle power supply system 1, power is supplied to the second load 32 by appropriately short-circuiting or opening the first switch 21 and the second switch 22 according to the situation of the vehicle.

  For example, assume that only the second switch 22 is short-circuited and the storage battery that drives the second load 32 is the lithium storage battery 52. At this time, when the output voltage or the storage capacity of the lithium storage battery 52 decreases, the second switch 22 is opened and the first switch 21 is short-circuited, so that the lead storage battery 51 becomes the storage battery driving the second load 32. In addition, the lithium storage battery 52 becomes a storage battery while the second load 32 is not driven.

  Here, "during driving" refers to driving the electric load, that is, supplying power to the electric load. On the other hand, “not driving” means that the electric load is not driven, that is, power is not supplied to the electric load. The drive battery referred to below refers to a storage battery that drives the second load 32 that is an electric load.

  As described above, the drive battery can be switched from the lithium storage battery 52 to the lead storage battery 51 by opening the second switch 22 and short-circuiting the first switch 21. However, depending on the switching timing, it is instantaneous. In this case, the power supply to the second load 32 may be lost. A similar problem may occur when switching the drive battery from the lead storage battery 51 to the lithium storage battery 52.

  Therefore, in order to suppress power supply loss, switching may be performed after a state in which power is supplied to the second load 32 by two storage batteries such as the lead storage battery 51 and the lithium storage battery 52. That is, it is conceivable to switch after passing through the overlap state. The overlap state refers to a state where both the first switch 21 and the second switch 22 are short-circuited. In the following, the overlap time refers to the time during which the apparatus is in the overlap state.

  However, in the overlap state, the current consumption of the first switch 21 and the second switch 22 increases as compared with the case where only one of the first switch 21 and the second switch 22 is short-circuited.

  If the output voltage of the lead storage battery 51 is higher than that of the lithium storage battery 52, the internal resistance of the lithium storage battery 52 increases in addition to the second load 32 as an electrical load when viewed from the lead storage battery 51. If the output voltage of the lithium storage battery 52 is higher than that of the lead storage battery 51, the first load 31, the internal resistance of the lead storage battery 51, and the starter 33 are electrically connected to the second load 32 as viewed from the lithium storage battery 52. This is because the load increases.

  Therefore, there is a concern that the first switch 21 and the second switch 22 may increase in temperature and cause a failure due to the temperature increase. Any of an open fault and a short-circuit fault can occur as a fault. In any case, a power supply defect may occur in the second load 32. The ECU 10 executes a switching process described below in order to switch the driving battery while suppressing such power supply loss.

[1-2. processing]
[1-2-1. Switching process]
Next, a switching process executed by the ECU 10 will be described with reference to a flowchart of FIG. The switching process is a process for driving the second load 32 using a plurality of storage batteries such as the lead storage battery 51 and the lithium storage battery 52. The switching process is repeatedly executed at a predetermined switching cycle. The switching period may be, for example, about several msec to several hundred msec.

ECU10 is in S10, acquires the temperature T _SW1 and the temperature T _SW2 of the second switch 22 of the first switch 21, respectively. Further, the overlap time stored in the memory 12 is obtained. The overlap time is a time during which both the first switch 21 and the second switch 22 are short-circuited. The overlap time is counted by an overlap time process which is executed by the ECU 10 and which is different from the main switching process, which will be described later. Note that the initial value of the overlap time is 0.

  In S20, the ECU 10 determines whether there is a switching request. The switching request means that the driving battery is a storage battery that is driving the second load 32 and is a storage battery that is not driving the second load 32 from one of the lead storage battery 51 and the lithium storage battery 52. This is a request for switching to the other of the lead storage battery 51 and the lithium storage battery 52, and is a request for the ECU 10.

  In the present embodiment, the ECU 10 is configured to determine whether a predetermined switching condition is satisfied, and to determine that there is a switching request when it is determined that the switching condition is satisfied. . When the ECU 10 determines that the switching condition is satisfied, the ECU 10 shifts the processing to S30, and when it determines that the switching condition is not satisfied, ends the switching processing.

  The switching condition means that the driving battery is a storage battery that is driving the second load 32 and is a storage battery that is not driving the electric load from the lithium storage battery 52 or one of the lithium storage batteries 52 and is a lead storage battery. This is a condition for switching to the other one of the storage battery 51 and the lithium storage battery 52.

  Here, the ECU 10 determines whether or not the switching condition, that is, the switching condition for switching the driving battery from the lithium storage battery 52 as one storage battery to the lead storage battery 51 as the other storage battery is satisfied. You may.

  The switching condition referred to here is that when only the second switch 22 of the first switch 21 and the second switch 22 is short-circuited and the power is supplied to the second load 32 by the lithium storage battery 52, Has changed from within a predetermined appropriate range to outside the appropriate range. SOC is an abbreviation of State of charge, and represents the ratio of the actual charge amount to the charge amount at full charge.

  Specifically, in the present embodiment, the ECU 10 acquires the output voltage of the lithium storage battery 52. The ECU 10 switches the output voltage of the lithium storage battery 52 when the output voltage of the lithium storage battery 52 changes from a voltage threshold value that is a predetermined voltage value to a voltage threshold value or less and the drive battery is not switched after the change. It is determined that the condition is satisfied.

  The voltage threshold (hereinafter, also referred to as an out-of-range threshold) is stored in the memory 12 in advance. Here, the switching of the driving battery is not performed when the second switch 22 connecting the lithium storage battery 52 as one storage battery and the second load 32 is still short-circuited, that is, not being open. Say.

  The ECU 10 calculates the SOC of the lithium storage battery 52, and changes the SOC of the lithium storage battery 52 from a percentage threshold, which is a predetermined percentage, to a percentage threshold, and then switches the driving battery after the change. If not, it may be determined that the switching condition is satisfied. The ratio threshold may be stored in the memory 12 in advance.

  On the other hand, the ECU 10 determines whether or not a switching condition, that is, a switching condition for switching the drive battery from the lead storage battery 51 as one storage battery to the lithium storage battery 52 as the other storage battery, is satisfied. Is also good.

  The switching condition referred to here is that when only the first switch 21 of the first switch 21 and the second switch 22 is short-circuited and the power is supplied to the second load 32 by the lead storage battery 51, the lithium storage battery 52 May have changed from outside the predetermined appropriate range to within the appropriate range.

  Specifically, in the present embodiment, the ECU 10 acquires the output voltage of the lithium storage battery 52. The ECU 10 switches the output voltage of the lithium storage battery 52 when the output voltage has changed from less than the predetermined voltage value, that is, the voltage threshold value to the voltage threshold value or more, and the drive battery has not been switched since the change. It is determined that the condition is satisfied.

  The voltage threshold (hereinafter, also referred to as a threshold in a range) is stored in the memory 12 in advance. The in-range threshold value may be the same value as the out-of-range threshold value which is the voltage threshold value under the above-described switching condition for switching the drive battery from the lithium storage battery 52 to the lead storage battery 51, or may be a different value. Here, the driving battery is not switched when the first switch 21 connecting the lead storage battery 51 and the second load 32, which is one of the storage batteries, is still short-circuited, that is, not opened. Say.

  The ECU 10 calculates the SOC of the lithium storage battery 52, and changes the SOC of the lithium storage battery 52 from less than a predetermined ratio, which is a ratio threshold, to a value equal to or higher than the ratio threshold. If not, it may be determined that the switching condition is satisfied.

  The ECU 10 may determine whether the switching condition is satisfied in the main switching process or in a process different from the main switching process. In addition, the ECU 10 may obtain a determination result as to whether the switching condition is satisfied from another ECU mounted on the vehicle.

In S30, the ECU 10 determines whether the temperatures T _SW1 and T _{SW2 of} the first switch 21 and the second switch 22 respectively satisfy the temperature condition. Here, the temperature condition is a condition that the temperature T _SW1 of the first switch 21 is lower than a predetermined temperature threshold and the temperature T _SW2 of the second switch 22 is lower than the temperature threshold.

The ECU 10 shifts the processing to S40 when the temperature condition is satisfied, and shifts the processing to S70 when the temperature condition is not satisfied.
In the present embodiment, the temperature threshold is a predetermined value, which is set to the same value for each of the first switch 21 and the second switch 22 and is stored in the memory 12 in advance. However, the temperature threshold may be set to a different value for each of the first switch 21 and the second switch 22.

As shown in FIG. 3, the temperature threshold value SW _TH is the maximum value H _M temperature variation that may be raised by both the first switch 21 and second switch 22 is short-circuited, the first switch 21 or is a value obtained by subtracting from the allowable maximum temperature SW _M of the second switch 22. The temperature threshold value SW _TH can be set by an experiment or the like based on the time during which both the first switch 21 and the second switch 22 are short-circuited, current consumption, and the like.

  In S40, the ECU 10 determines whether or not the vehicle is in the overlap state. Here, the ECU 10 shifts the processing to S70 when the overlap state is already present, and shifts the processing to S50 when the overlap state is not satisfied.

  In S50, the ECU 10 brings the first switch 21 and the second switch 22 into the overlap state. Specifically, the ECU 10 outputs an overlap signal to each of the first switch 21 and the second switch 22. The overlap signal is an instruction signal for short-circuiting the first switch 21 and short-circuiting the second switch 22.

Thereby, the lead storage battery 51 and the second load 32 are short-circuited, and the lithium storage battery 52 and the second load 32 are short-circuited.
In subsequent S60, the ECU 10 sets a count request flag. The count request flag is a flag that is set while counting the overlap time. The count request flag is reset when it is not necessary to count the overlap time, that is, when it is necessary to clear the overlap time. Clearing the overlap time means resetting the overlap time to zero. While the count request flag is set, the overlap time continues to be counted in the overlap time processing described later.

  In S70, the ECU 10 determines whether or not an overlap time of a predetermined length has elapsed. Specifically, if the overlap time is equal to or longer than the predetermined duration threshold, the ECU 10 determines that the predetermined length of overlap time has elapsed. The duration threshold value can be set to, for example, about several msec to several hundred msec.

  The duration threshold value can be set by experiments and calculations based on power consumption, etc., to such a time that even if the first switch 21 and the second switch 22 are continuously short-circuited, these switches do not fail due to a rise in temperature. The duration threshold is stored in the memory 12 in advance.

The ECU 10 shifts the processing to S80 if the overlap time is equal to or greater than the duration threshold, and ends the switching processing if the overlap time is less than the duration threshold.
In S80, the ECU 10 switches the driving battery. That is, the driving battery that is the storage battery that drives the second load 32 is the storage battery that is driving the second load 32 in a state before the overlap, and the storage battery is one of the lithium storage battery 52 and the lithium storage battery 52. In the state before the overlap, the electric load is switched to the other one of the lead storage battery 51 and the lithium storage battery 52 while the electric load is not being driven.

  Here, when the switching condition for switching the driving battery from the lithium storage battery 52 to the lead storage battery 51 is satisfied in S20 described above, the ECU 10 opens the connection between the lithium storage battery 52 and the second load 32, and And a switching signal for short-circuiting between the second loads 32.

  On the other hand, when the switching condition for switching the drive battery from the lead storage battery 51 to the lithium storage battery 52 is satisfied in S20 described above, the ECU 10 opens the space between the lead storage battery 51 and the second load 32, and A switching signal for short-circuiting between the second loads 32 is output.

In the following S90, the ECU 10 resets the count request flag. Thereby, the overlap time is cleared by the overlap time processing described later.
Thus, the ECU 10 ends the switching process.

[1-2-2. Overlap time processing]
The overlap time process will be described with reference to the flowchart shown in FIG. The ECU 10 executes the overlap time process at a predetermined execution cycle. The execution cycle may be, for example, about several milliseconds to several tens of milliseconds.

  In S110, ECU 10 determines whether or not it is required to count the overlap time. Specifically, when the above-described count request flag is set, the ECU 10 determines that counting is requested. Here, when counting is requested, the ECU 10 shifts the processing to S120, counts up the overlap time, and ends the overlap time processing. On the other hand, when the counting is not requested, the ECU 10 clears the overlap time and ends the overlap time processing. Clearing the overlap time means setting the overlap time to zero.

[1-2-3. Operation]
The operation of the vehicle power supply system 1 will be described with reference to a time chart shown in FIG. 5 and FIGS. In the present embodiment, the output voltage of the lead storage battery 51 is set to 12 V when fully charged, and the output voltage of the lithium storage battery 52 is set to about 12 V when fully charged. As described above, the output voltage of the lead storage battery 51 when fully charged is higher than the output voltage of the lithium storage battery 52 when fully charged.

  Further, in the present embodiment, under the switching condition for switching the driving battery from the lithium storage battery 52 to the lead storage battery 51, the out-of-range threshold that is the voltage threshold in the switching condition is set to 11V. In the switching condition for switching the drive battery from the lead storage battery 51 to the lithium storage battery 52, the threshold in the range, which is the voltage threshold in the switching condition, is set to 11.5V. Note that the output voltage and the voltage threshold are not limited to these, and may be set to arbitrary values.

  At time t1, the first switch 21 is open and the second switch 22 is short-circuited. That is, the lithium storage battery 52 is a driving battery. After time t1, the output voltage of lithium storage battery 52 decreases with time.

At time t2, as shown in FIG. 6, the output voltage of lithium storage battery 52 is less than 11V. That is, the output voltage of the lithium storage battery 52 changes from the voltage threshold or more to the voltage threshold or less and the switching condition for switching the driving battery from the lithium storage battery 52 to the lead storage battery 51 is satisfied. Subsequently, the ECU 10 determines whether the temperature condition is satisfied. Here, ECU 10, the temperature T _SW2 each temperature T _SW1 and the second switch 22 of the first switch 21 is less than a temperature threshold value SW _TH, it shall be identified.

  Therefore, as shown in FIG. 7, the ECU 10 first outputs an instruction signal for bringing the first switch 21 and the second switch 22 into the overlap state. Thus, the lithium storage battery 52 is charged by the lead storage battery 51. Since the lithium storage battery 52 is a storage battery with high charging efficiency, the remaining battery capacity can be increased with time and the output voltage can be increased by charging the lead storage battery 51 with time.

  Time t3 represents the time when the duration threshold has elapsed from time t2. At time t3, as shown in FIG. 8, the ECU 10 then causes the first switch 21 and the second switch 22 to open the space between the lithium storage battery 52 and the second load 32, and to open the space between the lead storage battery 51 and the second load 32. Output a switching signal for short-circuiting. In this way, the drive battery is switched from the lithium storage battery 52 to the lead storage battery 51.

At time t3, the output voltage V _Li of the lithium storage battery 52 is 11.5 V, and has increased from less than the voltage threshold to more than the voltage threshold. That is, after time t3, the switching condition for switching the drive battery from the lead storage battery 51 to the lithium storage battery 52 is satisfied. However, the temperature T _SW2 each temperature T _SW1 and the second switch 22 of the first switch 21 is not less than a temperature threshold value SW _TH, the temperature conditions are not met. Therefore, the ECU 10 does not switch the driving battery.

At the following time t4, the temperature condition is not satisfied. Therefore, the ECU 10 does not switch the driving battery. At time t4, if the first switch 21 and the second switch 22 are in the overlap state in order to switch the driving battery, as shown by a dotted line in the figure, the time when the duration threshold has elapsed from time t4. in t5, a temperature T _SW1 and the temperature T _SW2 of the second switch 22 of the first switch 21 may exceed the maximum allowed temperature SW _M.

At time t6, the temperature T _SW1 of the first switch 21 is _lower than the temperature threshold SW _TH and the temperature T _SW2 of the second switch 22 is _lower than the temperature threshold SW _TH , and the temperature condition is satisfied. That is, the switching condition for switching the drive battery from the lithium storage battery 52 to the lead storage battery 51 is satisfied, and the temperature condition is satisfied.

Therefore, as shown in FIG. 9, the ECU 10 outputs an instruction signal for bringing the first switch 21 and the second switch 22 into the overlap state.
Subsequently, at time t7 after the duration threshold has elapsed from time t6, the ECU 10 short-circuits the lithium storage battery 52 and the second load 32 to the first switch 21 and the second switch 22, as shown in FIG. Then, a switching signal for opening between the lead storage battery 51 and the second load 32 is output. In this way, the drive battery is switched from the lead storage battery 51 to the lithium storage battery 52.

In time t7, the temperature T _SW2 temperature T _SW1 and the second switch 22 of the first switch 21 is respectively less than the allowable maximum temperature SW _M. In this way, the ECU 10 can switch the drive battery without causing the first switch 21 and the second switch 22 to fail due to a rise in temperature.

[1-3. effect]
According to the first embodiment described in detail above, the following effects can be obtained.
(1a) In S40-S80, when it is determined that there is a switching request and that the temperature condition is satisfied, the ECU 10 outputs the overlap signal for the duration threshold and continues for the duration threshold. After outputting the overlap signal, the switching signal is output. When it is determined that there is a switching request and the temperature condition is not satisfied, no overlap signal and no switching signal are output. The switching signal is a signal that opens one of the two storage batteries and the second load 32 and short-circuits the other storage battery and the second load 32.

  As described above, when there is a switching request, the ECU 10 performs switching only when the temperature of the first switch 21 and the temperature of the second switch 22 satisfy predetermined temperature conditions. At the time of switching, the switching signal is output after outputting the overlap signal.

  As a result, when power is supplied to the electric load using the plurality of storage batteries, when the driving batteries are switched, the occurrence of a power supply defect in the second load 32 can be suppressed due to the overlap state.

  Further, by appropriately setting the temperature condition such as, for example, that the temperature is lower than a predetermined temperature, if the temperature condition is not satisfied, the overlap signal is not output, so that the first switch 21 and the second switch 22 Failure is suppressed. As a result, when power is supplied to the electric load by using the plurality of storage batteries, when the driving battery is switched, it is possible to suppress the occurrence of a power supply defect due to a switch failure in the second load 32.

  (1b) In S30, the ECU 10 may determine whether the temperature condition, that is, the condition that the temperature of each of the first switch 21 and the second switch 22 is lower than the temperature threshold, is satisfied. When the temperature of the first switch and the temperature of the second switch are each equal to or higher than the temperature threshold, no overlap signal is output. By setting the temperature threshold value to an upper limit value at which these switches do not fail, it is possible to prevent these switches from failing due to a rise in temperature. As a result, the same effect as (1a) can be obtained.

  (1c) In S20, the ECU 10 changes the drive battery that is the storage battery that drives the second load 32 from the storage battery that is driving the second load 32 and is one of the lead storage battery 51 and the lithium storage battery 52. It is determined whether or not a switching condition for switching the second load 32 to the other one of the lead storage battery 51 and the lithium storage battery 52 while the second load 32 is not being driven is satisfied, and the switching condition is satisfied. It is determined that there is a switching request to the ECU 10 in the case where it is performed.

  As a result, the ECU 10 performing the switching determines whether or not the switching condition is satisfied. Therefore, the time lag at the time of the determination is shorter than when the determination is performed by a device other than the ECU 10 and the result is obtained. Can be suppressed.

  (1d) In S20, the ECU 10 determines whether or not a switching condition for switching the driving battery from the lithium storage battery 52 as one storage battery to the lead storage battery 51 as the other storage battery is satisfied, and determines whether the switching condition is satisfied. Is satisfied, it is determined that there is a switching request. After outputting the overlap signal, the ECU 10 opens a connection signal between the lithium storage battery 52 and the second load 32 as one storage battery, and outputs a switching signal for short-circuiting the lead storage battery 51 and the second load 32 as the other storage battery. May be.

As a result, the drive battery can be switched from the lithium storage battery 52 to the lead storage battery 51, and at the time of the switching, the same effect as (1a) can be obtained.
(1e) In S20, the ECU 10 determines whether or not a switching condition for switching the driving battery from the lead storage battery 51, which is one storage battery, to the lithium storage battery 52, which is the other storage battery, is satisfied. If it is satisfied, it is determined that there is a switching request. After outputting the overlap signal, the ECU 10 outputs a switching signal that opens the space between the lead storage battery 51 and the second load 32 as one storage battery and short-circuits the lithium storage battery 52 and the second load 32 as the other storage battery. May be.

As a result, the drive battery can be switched from the lead storage battery 51 to the lithium storage battery 52, and the same effect as (1a) can be obtained when switching.
(1f) In the vehicle power supply system 1, the lead storage battery 51 is connected to the alternator 41, which is a charging device that can charge at least the lead storage battery 51.

  As a result, the lead storage battery 51 can be charged by the alternator 41 regardless of the connection state of the first switch 21 and the second switch 22. The first load 31 is connected to the lead storage battery 51. That is, power can be supplied to the first load 31 regardless of the connection state of the first switch 21 and the second switch 22.

  (1g) The output voltage of the lead storage battery 51 is always higher than the output voltage of the lithium storage battery 52. As a result, in the overlap state in which the second load 32 and the lithium storage battery 52 are connected to the lead storage battery 51, the lithium storage battery 52 can be charged by the lead storage battery 51.

[1-4. Modification]
Next, a modified example of the first embodiment will be described.
[1-4-1. Modification 1]
As shown in FIG. 11, the ECU 10 estimates a predicted temperature, which is a temperature after a lapse of a duration threshold of each of the first switch 21 and the second switch 22, based on the temperature of each of the first switch 21 and the second switch 22. It may be configured as follows.

  Here, the predicted temperature is calculated by adding a predicted rise value to the current switch temperature. The rise prediction value is a value obtained by calculating power consumption based on a conduction current in each switch and a duration threshold value that is a time during which the conduction current flows, and predicting a temperature rise from the power consumption. The conduction current in each switch is based on the difference between the output voltage of the lead storage battery 51 and the output voltage of the lithium storage battery 52, the resistance value of each switch when a short circuit occurs, and the internal resistance of the lead storage battery 51 and the lithium storage battery 52. Can be calculated.

Then, the ECU 10 determines that the predicted temperature P _SW1 of the first switch 21 is _lower than the predetermined predicted threshold SW _PTH and that the predicted temperature P _SW2 of the second switch 22 is _lower than the predetermined predicted threshold SW _PTH. , May be configured to determine whether the temperature condition is satisfied. Here, the prediction threshold value SW _PTH can be set to at least a temperature higher than the prediction temperature. For example, the prediction threshold may be set to a temperature that is higher than the predicted temperature by a predetermined temperature. The predetermined temperature can be set to a smaller value as the calculation accuracy of the predicted temperature is higher.

  Note that the prediction threshold value for the first switch 21 and the prediction threshold value for the second switch 22 may be set to the same value or different values. In the present embodiment, the prediction threshold for the first switch 21 and the prediction threshold for the second switch 22 are set to the same value.

As shown in FIG. 12, the switching process in the first modification is different from FIG. 2 in that S25 is added and S30 is replaced with S35.
Specifically, in the switching process, in S10-S20, the ECU 10 executes the same process as S10-S20 in FIG.

ECU10 is the S25, based on the respective temperature of the temperature and the second switch 22 of the first switch 21, a predicted temperature P _SW2 predicted temperature P _SW1 and the second switch 22 of the first switch 21.

In S35, in S35, the temperature condition is such that the predicted temperature _PSW1 of the first switch 21 is _lower than the predicted threshold _SWPTH , and the predicted temperature _PSW2 of the second switch 22 is _lower than the predicted threshold _SWPTH . It is determined whether the temperature condition is satisfied. The ECU 10 shifts the processing to S40 if the temperature condition is satisfied, and shifts the processing to S70 if the temperature condition is not satisfied. After S40, the ECU 10 executes the same processing as that after S40 in FIG.

As a result, in the first modification, the prediction threshold SW _PTH can be set near the maximum allowable temperature SW _M by increasing the estimation accuracy of the prediction temperature. That is, the first switch 21 and the second switch 22 can be in the overlap state for a longer period.

[1-4-2. Modification 2]
In the vehicle power supply system 1, the alternator 41 may be configured to perform deceleration regeneration in which the lead storage battery 51 and the lithium storage battery 52 are charged by power generation when the vehicle is decelerated.

  As shown in FIG. 13, during deceleration operation of the vehicle, the first switch 21 and the second switch 22 are both short-circuited, and the alternator 41 performs regenerative charging of the lead storage battery 51 and the lithium storage battery 52, and performs the first load 31 and the second load. Power is supplied to the two loads 32. Since the lithium storage battery 52 is a storage battery with high charging efficiency, the remaining capacity of the lithium storage battery 52 can be increased by regenerative charging during deceleration operation of the vehicle.

  The ECU 10 sends an instruction signal to the first switch 21 and the second switch 22 so that both the first switch 21 and the second switch 22 are short-circuited only when the above-mentioned temperature condition is satisfied even during the deceleration operation of the vehicle. May be configured to be output.

[2. Second Embodiment]
[2-1. Constitution]
The second embodiment has the same basic configuration as that of the first embodiment, and therefore, differences will be described below. The same reference numerals as in the first embodiment denote the same components, and refer to the preceding description.

  In the present embodiment, as shown in FIG. 14, the vehicle power supply system 2 includes an ISG 42 instead of the alternator 41, and further includes a third switch 23 and a fourth switch 24 in addition to the first switch 21 and the second switch 22. The first embodiment differs from the first embodiment in that the first embodiment is provided. ISG is an abbreviation for Integrated Starter Generator.

  The lithium storage battery 52 and the first to fourth switches 21 to 24 are housed and integrated in a housing, and are configured as the switch unit 20. Like the first switch 21 and the second switch 22, the third switch 23 and the fourth switch 24 are switched between short circuit and open according to an instruction signal from the ECU 10.

  The switch unit 20 is provided with a first terminal P1, a second terminal P2, and a third terminal P3 as external terminals. The external terminal is a terminal for connecting the switch unit 20 to the outside of the switch unit 20. The lead-acid battery 51, the starter 33, and the first load 31 are connected to the first terminal P1. The ISG 42 is connected to the second terminal P2. The second load 32 is connected to the third terminal P3.

The ISG 42 has a power generation function of generating power by rotating the crankshaft of the engine, and a power output function of applying a rotational force to the crankshaft.
Specifically, the ISG 42 has a rotating machine (not shown). The rotating machine is drivably connected to a crankshaft of the engine by a belt or the like. The rotating shaft of the rotating machine rotates by the rotation of the crankshaft, and the crankshaft rotates by the rotation of the rotating shaft of the rotating machine. . That is, the ISG 42 realizes a power generation function and a power output function by the rotating machine. Note that the ISG 42 may have a function of performing regenerative power generation.

  The lead storage battery 51 and the lithium storage battery 52 are connected in parallel to the ISG 42, and the lead storage battery 51 and the lithium storage battery 52 can be charged by the power generated by the ISG 42. The ISG 42 is connected to the lead storage battery 51 via the fourth switch. ISG 42 is connected to lithium storage battery 52 via third switch 23. The ISG 42 can be driven by being supplied with power from the lead storage battery 51 and the lithium storage battery 52.

[2-2. processing]
[2-2-1. Switching process]
In the switching process of this embodiment, the ISG 42 charges the lower output voltage of the lithium storage battery 52 and the lead storage battery 51 to reduce the difference between the output voltage of the lead storage battery 51 and the output voltage of the lithium storage battery 52. It differs from the first embodiment in that the drive battery is switched. Specifically, as shown in FIG. 15, the switching process of the present embodiment differs from the switching process of the first embodiment shown in FIG. 2 in that S10 is replaced with S15, and S22-S24 are added. They are different in that respect.

In the switching process of the present embodiment, in S15, the ECU 10 further obtains the output voltage V _Pb of the lead storage battery 51 and the output voltage V _Li of the lithium storage battery 52 in addition to the process of S10 shown in FIG.

  In subsequent S20, the ECU 10 executes the same processing as in FIG. However, if it is determined in S20 that there is a switching request, that is, if it is determined that the switching condition is satisfied, the ECU 10 shifts the processing to S22.

In S22, the ECU 10 determines whether or not the absolute value of the difference between the output voltage V _Pb of the lead storage battery 51 and the output voltage V _Li of the lithium storage battery 52 is equal to or greater than a predetermined difference threshold. The ECU 10 shifts the processing to S30 when the absolute value of the difference between these output voltages is less than the difference threshold, and shifts the processing to S24 when the absolute value of the difference between these output voltages is equal to or greater than the difference threshold. .

  The difference threshold may be set to a value less than 1V, for example, 0.5V. However, the present invention is not limited to this, and the difference threshold may be set to an arbitrary value. The difference threshold is stored in the memory 12 in advance.

In S24, the ECU 10 uses the ISG 42 to charge the lower storage voltage of the two storage batteries for a predetermined time.
Here, when the switching condition for switching the drive battery from the lithium storage battery 52 to the lead storage battery 51 is satisfied in S20, the ECU 10 determines that the output voltage V _Li of the lithium storage battery 52 is higher than the output voltage V _Pb of the lead storage battery 51. If it is low, an instruction signal for short-circuiting the third switch is output to the switch unit 20, and the lithium storage battery 52 is charged by the ISG 42 for a predetermined time.

On the other hand, when the switching condition for switching the drive battery from the lead storage battery 51 to the lithium storage battery 52 is satisfied in S20, the ECU 10 determines that the output voltage _VPb of the lead storage battery 51 is lower than the output voltage V _Li of the lithium storage battery 52. In such a case, an instruction signal for short-circuiting the fourth switch may be output to the switch unit 20, and the lead storage battery 51 may be charged by the ISG 42 for a predetermined time.

After S30, the ECU 10 performs the same processing as that after S30 in FIG.
[2-2-2. Operation]
The operation of the vehicle power supply system 2 will be described with reference to a time chart shown in FIG. 16 and FIGS. In the present embodiment, the output voltage when the lead storage battery 51 is fully charged and the output voltage when the lithium storage battery 52 is fully charged are set to 12V. The threshold outside the range as the voltage threshold in the switching condition is set to 11V, and the threshold inside the range is set to 12V. The difference threshold is set to 0.5V. Note that the output voltage, voltage threshold, and difference threshold at the time of full charge are not limited to these, and may be set to arbitrary values.

At time t11, the first switch 21 is opened, the second switch 22 is short-circuited, the third switch 23 is opened, and the fourth switch 24 is opened. That is, the lithium storage battery 52 is a driving battery. After time t11, the output voltage V _Li of the lithium storage battery 52 decreases with time.

At time t12, as shown in FIG. 17, the output voltage V _Li of the lithium storage battery 52 is less than 11V. That is, the output voltage V _Li of the lithium storage battery 52 changes from the out-of-range threshold or more to less than the out-of-range threshold, and before the switching of the driving battery is performed. The switching condition is satisfied. Here, in the present embodiment, the ECU 10 determines that the absolute value of the difference between the output voltage of the lithium storage battery 52 and the output voltage of the lead storage battery 51 is equal to or greater than the difference threshold.

  At time t13, the ECU 10 further short-circuits the third switch, as shown in FIG. That is, at time t13, the first switch 21 is short-circuited, the second switch 22 is short-circuited, the third switch 23 is short-circuited, and the fourth switch 24 is opened. The ECU 10 thereby charges the lithium storage battery 52 by the ISG 42 for a predetermined time.

  Time t14 is a predetermined time after the time t13. The ECU 10 opens the third switch and ends the charging of the lithium storage battery 52 by the ISG 42. That is, at this point, the connection state is the same as in FIG. At this point, as shown in FIG. 16, the absolute value of the difference between the output voltage of the lithium storage battery 52 and the output voltage of the lead storage battery 51 is less than the difference threshold.

At time t15, the ECU 10 determines whether the temperature condition is satisfied. Here, ECU 10, the temperature T _SW2 each temperature T _SW1 and the second switch 22 of the first switch 21 is less than a temperature threshold value SW _TH, it shall be identified. Therefore, the ECU 10 first outputs to the switch unit 20 an instruction signal for bringing the first switch 21 and the second switch 22 into the overlap state.

  That is, as shown in FIG. 19, the first switch 21 is short-circuited, the second switch 22 is short-circuited, the third switch 23 is opened, and the fourth switch 24 is opened. As a result, the first switch 21 and the second switch 22 are in the overlap state, and the lithium storage battery 52 is charged by the lead storage battery 51. Since the lithium storage battery 52 is a storage battery with high charging efficiency, the remaining battery capacity can be increased with time and the output voltage can be increased by charging the lead storage battery 51 with time.

  Time t16 represents the time when the duration threshold has elapsed from time t15. At time t16, as shown in FIG. 20, the ECU 10 causes the switch unit 20 to open the second switch 22 provided between the lithium storage battery 52 and the second load 32, and to switch between the lead storage battery 51 and the second load 32. And a switching signal for short-circuiting the first switch provided. As a result, the drive battery is switched from the lithium storage battery 52 to the lead storage battery 51.

  The ECU 10 may be configured to charge the lithium storage battery 52 that is not driving the second load 32 by the ISG 42 when the drive battery is switched from the lithium storage battery 52 to the lead storage battery 51. That is, as shown in FIG. 20, the first switch 21 may be short-circuited, the second switch 22 may be opened, the third switch 23 may be short-circuited, and the fourth switch 24 may be opened.

Thereby, while the second load 32 is being driven by the lead storage battery 51, the lithium storage battery 52 can be charged so as to approach the voltage value at the time of full charge.
[2-3. effect]
According to the second embodiment described in detail above, the effects (1a)-(1b) and (1d) of the above-described first embodiment can be obtained, and further, the following effects can be obtained.

  (2a) The lead storage battery 51 is connected to the ISG 42 that can charge at least one of the lead storage battery 51 and the lithium storage battery 52 via the fourth switch 24 that is switched between short circuit and open in accordance with an instruction signal from the ECU 10. You. The lithium storage battery 52 is connected to the ISG 42 via the third switch 23 that switches between short circuit and open in accordance with an instruction signal from the ECU 10.

As a result, the lead storage battery 51 and the lithium storage battery 52 can be charged at an appropriate timing by the ISG 42.
(2b) When it is determined that the switching condition is satisfied, the ECU 10 determines whether or not the absolute value of the difference between the output voltage of the lead storage battery 51 and the output voltage of the lithium storage battery 52 is equal to or greater than a predetermined difference threshold. It may be configured to determine. If the absolute values of these differences are equal to or greater than the difference threshold, the ECU 10 short-circuits the switch unit 20 between the lead battery 51 and the lithium battery 52 having a lower output voltage and the ISG 42 for a predetermined period. It may be configured to output an instruction signal. That is, the ECU 10 may be configured to short-circuit one of the fourth switch 24 and the third switch 23 that is connected to the storage battery having a low output voltage.

  After outputting the instruction signal for a predetermined period, the ECU 10 determines whether or not the temperature condition is satisfied. If the temperature condition is satisfied, the ECU 10 switches the driving battery via the overlap state. May be configured.

  As a result, by charging the battery with the ISG 42, the drive battery is switched after the voltage difference between the lead storage battery 51 and the lithium storage battery 52 is reduced. Therefore, it is possible to suppress the flow of an excessive current in the overlap state. it can. Further, by setting the overlap state, it is not necessary to charge the storage battery having the lower output voltage, so that the overlap time can be reduced.

  (2c) When the switching signal is output, the ECU 10 outputs the switching signal of the lead storage battery 51 and the lithium storage battery 52 to the switch unit 20 together with the switching signal, so that the second load 32 is not driven. It may be configured to output an instruction signal so that the storage battery to be charged by the ISG 42. That is, the ECU 10 may be configured to short-circuit the switch connected to the storage battery that is not driving the second load 32 among the fourth switch 24 and the third switch 23. The instruction signal may be continuously output until the output voltage of the storage battery that is not driven becomes equal to or higher than the threshold value within the range.

  As a result, the drive battery can be switched and the storage battery that is newly not driven can be charged. In addition, this makes it unnecessary to recharge the storage battery which is newly not driven by setting the overlap state, so that the overlap time can be reduced. In addition, by charging in this manner, the output voltage of the storage battery that is newly non-driven can be set to be equal to or higher than the threshold value within the range, and the charged non-driven storage battery can be newly switched as the drive battery.

  (2d) The ECU 10 determines the difference between the output voltage of the lead storage battery 51 and the output voltage of the lithium storage battery 52 when it is determined that the switching condition for switching the driving battery from the lithium storage battery 52 to the lead storage battery 51 is satisfied. May be configured to determine whether or not is greater than or equal to a predetermined difference threshold. When these differences are equal to or greater than the difference threshold, the ECU 10 sends an instruction signal to the switch unit 20 to short-circuit the third switch 23, which is a switch provided between the lithium storage battery 52 and the ISG 42, for a predetermined period. It may be configured to output.

  Further, when outputting the switching signal, the ECU 10 sends to the switch unit 20 the switching signal for switching the driving battery from the lithium storage battery 52 to the lead storage battery 51 and the lithium storage battery 52 that is not driving the second load 32. It may be configured to output an instruction signal for short-circuiting the third switch 23 so as to be charged by the ISG 42. The instruction signal may be continuously output until the output voltage of the non-driven storage battery becomes equal to or higher than the threshold value in the range.

As a result, when the driving battery is switched from the lithium storage battery 52 to the lead storage battery 51, the effects (2b) and (2c) can be obtained.
[2-4. Modification]
Next, a modification of the second embodiment will be described.

[2-4-1. Modification 3]
In the third modification, the ECU 10 may be configured to execute the same switching processing as in the first embodiment. That is, the ECU 10 may be configured to perform control to short-circuit and open the first switch 21 and the second switch 22 in the switch unit 20, as in the first embodiment.

[2-4-2. Modification 4]
In the fourth modification, the ECU 10 may be configured to determine whether the temperature condition is satisfied based on the temperature condition shown in the first modification.

[3. Other Embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and can be implemented with various modifications.

  (3a) In the above embodiment, the ECU 10 is configured to determine that there is a switching request when the switching condition is satisfied, but the present invention is not limited to this. The switching request may be output from another ECU mounted on the vehicle. That is, another ECU may be configured to determine whether the switching condition is satisfied, and may be configured to output a switching request to the ECU 10 when the switching condition is satisfied.

The ECU 10 may be configured to acquire a switching request output from another ECU, and may be configured to determine that there is a switching request when the switching request is acquired.
(3b) A plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. . Also, a plurality of functions of a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of another above-described embodiment. Note that all aspects included in the technical idea specified by the language described in the claims are embodiments of the present disclosure.

  (3c) The present disclosure is provided in various forms such as the above-described vehicle power supply systems 1 and 2, the ECU 10, a program for causing the ECU 10 to function, a non-changeable recording medium such as a semiconductor memory storing the program, a switching method, and the like. It can also be achieved.

  The ECU 10 corresponds to a power supply control device, the lead storage battery 51 corresponds to a first storage battery, the lithium storage battery 52 corresponds to a first storage battery, the first switch 21 corresponds to a first connection switch, and the second switch 21 corresponds to a second connection switch. The switch 22 corresponds to a second connection switch, the third switch 23 corresponds to a second charging switch, and the fourth switch 24 corresponds to a first charging switch. Further, the second load 32 corresponds to an electric load.

  Further, S10 corresponds to a process as a temperature obtaining unit, S20 corresponds to a process as a switching determining unit, S25 corresponds to a process as a temperature estimating unit, and S30 and S35 correspond to processes as a temperature determining unit. I do. Also, S40 to S80 correspond to the processing as the storage battery switching unit.

  The overlap signal corresponds to the superimposition signal, and the duration threshold corresponds to the superposition time.

  10 ECU, 21 1st switch, 22 2nd switch 22, 23 2nd charge switch 23, 24 1st charge switch 24, 32 2nd load, 51 lead storage battery, 52 lithium storage battery.

Claims (8)

A power supply control device (10) capable of driving an electric load by a plurality of storage batteries,
The plurality of storage batteries include a first storage battery (51) and a second storage battery (52),
The power control device,
A switch that switches between short-circuit and open in accordance with an instruction signal from the power supply control device, a first connection switch that short-circuits or opens between the first storage battery and the electric load, a second storage battery and the electric load A temperature acquisition unit (S10) for acquiring the respective temperatures of the second connection switch that short-circuits or opens the interval,
A storage battery that drives the electric load, a storage battery that is driving the electric load, and a storage battery that is not driving the electric load from one of the first storage battery and the second storage battery. A switching determination unit (S20) for determining whether there is a switching request for switching to the other storage battery of the first storage battery and the second storage battery;
A temperature determination unit (S30, S35) for determining whether the temperature of each of the first connection switch and the second connection switch satisfies a predetermined temperature condition;
When it is determined that the switching request is present and the temperature condition is satisfied, at least a superimposition signal that short-circuits the first connection switch and short-circuits the second connection switch, which is the instruction signal, is predetermined. And outputs a switching signal after outputting the superimposition signal. When it is determined that the switching request is present and the temperature condition is not satisfied, the superposition signal and the switching signal are not output. A storage battery switching unit (S40-S80);
With
The power supply control device, wherein the switching signal is the instruction signal, which is a signal that opens between the one storage battery and the electric load and short-circuits the other storage battery and the electric load. The power supply control device according to claim 1,
The temperature determination unit (S30) determines whether or not the temperature condition is satisfied, that is, the temperature of each of the first connection switch and the second connection switch is lower than a predetermined temperature threshold. Power control device to judge. The power supply control device according to claim 1,
A temperature estimating unit that estimates a predicted temperature that is the temperature of each of the first connection switch and the second connection switch after the lapse of the superimposition period, based on the temperatures of the first connection switch and the second connection switch; )
Further comprising
The temperature determination unit (S35) is configured to determine whether the temperature condition satisfies a condition that the predicted temperature of each of the first connection switch and the second connection switch is less than a predetermined prediction threshold. Power control device to determine whether. The power supply control device according to any one of claims 1 to 3, wherein
The switching determination unit is configured to change a drive battery that is a storage battery that drives the electric load from a storage battery that is driving the electric load and is one of the first storage battery and the second storage battery. It is determined whether or not a switching condition for switching to the other one of the first storage battery and the second storage battery, which is a non-operating storage battery, is satisfied, and if the switching condition is satisfied, the switching is performed. Power control unit that determines that there is a request. The power supply control device according to claim 4, wherein
The switching determination unit satisfies, as the switching condition, a switching condition for switching the drive battery from the second storage battery that is the one storage battery to the first storage battery that is the other storage battery. Judge whether or not
When it is determined that the switching condition is satisfied and the temperature condition is satisfied, the storage battery switching unit outputs the superimposition signal, and then outputs the superimposition signal and outputs the superimposition signal. A power supply control device that outputs a switching signal that opens between a storage battery and the electric load and short-circuits the first storage battery and the electric load that are the other storage battery. The power supply control device according to claim 4 or claim 5,
The switching determination unit satisfies, as the switching condition, a switching condition for switching the drive battery from the first storage battery as the one storage battery to the second storage battery as the other storage battery. Judge whether or not
When it is determined that the switching condition is satisfied and the temperature condition is satisfied, the storage battery switching unit outputs the superimposition signal, and then outputs the superimposition signal and outputs the switching signal. A power supply control device for opening a connection between a storage battery and the electric load and outputting a switching signal for short-circuiting between the second storage battery as the other storage battery and the electric load. The power supply control device according to any one of claims 1 to 6, wherein
A power supply control device, wherein the first storage battery is connected to at least a charging device capable of charging the first storage battery. The power supply control device according to any one of claims 1 to 7, wherein
The first storage battery is connected to a charging device capable of charging at least one of the first storage battery and the second storage battery, and a first charging switch (switchable between a short circuit and an open circuit according to an instruction signal from the power supply control device). 24), and the second storage battery is connected to the charging device via a second charging switch (23) that switches to either short circuit or open in accordance with an instruction signal from the power supply control device. Power control device.