JP7010187B2 - Vehicle power system control method, vehicle power system - Google Patents

Description

The present invention relates to a vehicle power supply system.

Currently, each automobile manufacturer is actively developing automatic braking systems and automatic driving technologies. Such a flow of vehicle electrification has further increased the importance of vehicle power supplies. As the power source for vehicles, the power supply by one lead battery and an alternator is still the mainstream. If the battery suddenly breaks down or the harness connected to the external terminal is disconnected, the power supply to the vehicle may be interrupted, so it is required to connect two batteries in parallel to provide redundancy. rice field. Document 1 below describes that a vehicle power supply device includes a control device, an electric load, a main relay, a starter, an alternator, a lead storage battery, a nickel hydrogen rechargeable battery, and the like. ..

Japanese Unexamined Patent Publication No. 2015-67042

In order to ensure safety, the battery may be provided with a current cutoff device that cuts off the current when overcharged. In a power supply system that connects two batteries in parallel, if one of the two batteries is overcharged, even if the current of one battery is cut off, the other battery will supply power to the vehicle. It is possible to continue.
However, if charging continues after the current of one battery is cut off, the voltage of the other battery rises. If the current is cut off when the other battery is overcharged, both batteries will be cut off and the power supply to the vehicle will be cut off.
Even if the two batteries are overcharged, it is desirable to secure a time until the vehicle can be stopped safely, and countermeasures have been required.

The present invention has been completed based on the above circumstances, and an object thereof is to secure a time until the vehicle can be safely stopped when two batteries connected in parallel are overcharged. And.

The control method of the vehicle power supply system includes a step of detecting the voltage of the first power storage unit connected to the vehicle load and detecting the voltage of the second power storage unit connected in parallel to the first power storage unit. When both the first storage unit and the second storage unit are overcharged, the current of the first storage unit and the second storage unit that cut off the current of the first storage unit is cut off. Includes a step of CLOSE both of the second current breakers.

The vehicle power supply system is connected in parallel to the first power storage unit connected to the vehicle load, the first current cutoff device that cuts off the current of the first power storage unit, and the first power storage unit. A second storage unit, a second current cutoff device that cuts off the current of the second storage unit, and a control unit are provided. In the control unit, both the first storage unit and the second storage unit are excessive. In the case of charging, both the first current cutoff device and the second current cutoff device are CLOSEd.

When two power storage units connected in parallel are overcharged, it is possible to secure a time until the vehicle can be safely stopped.

Side view of the vehicle in the first embodiment Power system block diagram Block diagram showing the electrical configuration of the battery An exploded perspective view of the battery Plan view of secondary battery FIG. 5A is a cross-sectional view taken along the line AA. The figure which shows the charge curve of a secondary battery Power system charge control sequence diagram Sequence diagram of charge control of power supply system in Embodiment 2. Block diagram of the power supply system according to the third embodiment Flow chart of the limitation process of the charge electric energy Q in the fourth embodiment Block diagram of power supply system in other embodiments

The control method of the vehicle power supply system includes a step of detecting the voltage of the first power storage unit connected to the vehicle load and detecting the voltage of the second power storage unit connected in parallel to the first power storage unit. When both the first storage unit and the second storage unit are overcharged, the current of the first storage unit and the second storage unit that cut off the current of the first storage unit is cut off. Includes a step of CLOSE both of the second current breakers.

When the power storage unit becomes overcharged, the general idea is to secure the safety of the power storage unit by opening the current cutoff device to cut off the current. In this method, contrary to the conventional idea of ensuring the safety of the power storage unit by cutting off the current, when both the first power storage unit and the second power storage unit are overcharged, the first current cutoff device and the second current are used. CLOSE the shutoff device. By CLOSE the current cutoff device, the first power storage unit and the second power storage unit are connected to the vehicle even after overcharging, so that it is possible to prepare for power supply due to sudden load fluctuation of the vehicle. .. By CLOSEing both the first current cutoff device and the second current cutoff device, when charging continues after overcharging, the charging current can be shared and received by the two power storage units. By sharing and accepting the charging current between the two storage units, the voltage rise of the first storage unit and the second storage unit becomes slower than when the charging current is received by only one storage unit. Therefore, it takes a long time for the first power storage unit and the second power storage unit to reach a voltage at which the battery performance is lost, so that it is possible to secure a time until the vehicle can be safely stopped.

As for the control method of the power supply system, when one of the first storage unit and the second storage unit is overcharged, the current cutoff device of the one storage unit that has reached overcharge opens. The current cutoff device of the other power storage unit that has not been overcharged may be maintained in CLOSE.

In this method, even after one of the power storage units is cut off, the other power storage unit can maintain the connection with the vehicle. By maintaining the connection with the vehicle, charging can be continued at the other power storage unit that has not reached overcharging.

The control method of the power supply system is that when the other power storage unit becomes overcharged, the current cutoff device of the one power storage unit is switched from OPEN to CLOSE, and the current cutoff device of the other power storage unit is switched. May include the step of maintaining CLOSE.

In this method, even after the two power storage units are overcharged, the power storage units maintain the connection with the vehicle, so that it is possible to prepare for power supply against sudden load fluctuations of the vehicle. After the two storage units are overcharged, the charging current is shared and received by the two storage units, so it is possible to suppress the voltage rise of the storage units and secure the time until the vehicle can be stopped safely. Can be done.

The control method of the power supply system may further include a warning step for requesting the vehicle to stop when both the first power storage unit and the second power storage unit are overcharged.

In this method, it is possible to prevent the driver from continuing to run without noticing the abnormality after the two power storage units are overcharged, and to urge the driver to stop the vehicle.

Further, in the control method of the power supply system, when the engine is stopped after the vehicle is stopped, both the first current cutoff device and the second current cutoff device are opened to open the first power storage unit and the second power storage unit. It may include a step prohibiting the use of the unit.

In this method, even after the two power storage units are overcharged, the engine is stopped after the vehicle is stopped while maintaining the connection between the power storage units and the vehicle to secure the time until the vehicle stops safely. After that, the use of the overcharged first power storage unit and the second power storage unit can be prohibited.

The control method of the power supply system is that when the charging electricity amount of the first storage unit or the second storage unit exceeds the limit electricity amount after overcharging, the corresponding current cutoff device is opened and the limit electricity amount is exceeded. It may include a step of cutting off the current of the power storage unit.

In this method, when the amount of charging electricity exceeds the limit amount of electricity after overcharging, the current is cut off, so that it is possible to prevent the power storage unit from being charged in excess of the limit amount of electricity. By setting the limit amount of electricity within a range in which the power storage unit can maintain the battery performance, it is possible to prevent the power storage unit from losing the battery performance due to charging.

<Embodiment 1>
1. 1. Explanation of Vehicle Power System 30 As shown in FIG. 1, the vehicle 10 is an engine-driven vehicle, and includes an engine starting device 21 such as a starter motor and a power supply system 30. Although FIG. 1 is omitted, the vehicle 1 is equipped with an alternator 23, which is a vehicle generator, and an electric load 25, in addition to the engine starting device 21. The electric load 25 has a rating of 12 V, and can exemplify an air conditioner, audio, car navigation, and the like.

FIG. 2 is a block diagram showing an electrical configuration of the vehicle power supply system 30.
The power supply system 30 includes a first battery 50A, a second battery 50B, a vehicle ECU (Electronic Control Unit) 31, and a DC-DC converter 35. The vehicle ECU 31 is an example of a control unit.

The first battery 50A includes a first current cutoff device 53A, a first set battery 60A, and a first management device 100A, and the second battery 50B includes a second current cutoff device 53B, a second set battery 60B, and a second management device. Includes 100B. The first battery 50A and the second battery 50B are rated at 12V. The first set battery 60A is an example of the first power storage unit, and the second set battery 60B is an example of the second power storage unit.

The first battery 50A is connected to the power line 37. An engine starting device 21, an alternator 23, and an electric load 25 are connected to the first battery 50A via a power line 37. The engine starting device 21 and the electric load 25 are examples of the vehicle load.

The second battery 50B is connected to the first battery 50A via the DC-DC converter 35. The DC-DC converter 35 is a bidirectional DC-DC converter capable of controlling charging and discharging of the second battery 50B. The DC-DC converter 35 is an adjusting device that controls charging / discharging of the second battery 50B. The adjusting device may be other than the DC-DC converter.

The vehicle ECU 31 is communicably connected to the first battery 50A, the second battery 50B, and the DC-DC converter 35. The vehicle ECU 31 is a control unit of the power supply system 30, and includes a CPU 32 and a memory 33. The vehicle ECU 31 receives monitoring data from the batteries 50A and 50B at regular intervals. The CPU 32 controls the charge / discharge of the batteries 50A and 50B by controlling the DC-DC converter 35 according to the states of the batteries 50A and 50B. The memory 33 stores a program for executing charge / discharge control.

The vehicle ECU 31 can obtain information on the operating state of the engine and the running state of the vehicle 10 from another vehicle ECU that controls the engine (driving device) of the vehicle 10.

The DC-DC converter 35 can control the power supply from the battery 50B to the electric load 25 by controlling the voltage at point A on the load side. By raising the voltage at point A higher than the output voltage of the alternator 23, power is supplied to the electric load 25, and by lowering the voltage at point A than the output voltage of the alternator 23, the power to the electric load 25 is supplied. Supply can be stopped (discharge control).

The DC-DC converter 35 can control the power supply to the battery 50B by controlling the voltage at point B on the battery side. By making the voltage at point B higher than the output voltage of the second battery 50B, power is supplied from the alternator 23 to the second battery 50B via the power line 37, and the voltage is B higher than the output voltage of the second battery 50B. By lowering the voltage at the point, the power supply to the second battery 50B can be stopped (charge control).

By connecting two batteries 50A and 50B in parallel, even if an abnormality occurs in one battery (for example, the first battery 50A: main battery), the other battery (for example, the second battery 50B: sub-battery) occurs. ), The power supply to the vehicle 10 can be continued, and the power supply of the vehicle 10 can be made redundant.

FIG. 3 is a block diagram showing an electrical configuration of the first battery 50A. The first battery 50A includes a first current cutoff device 53A, a first set battery 60A, a current sensor 54, a first management device 100A, a temperature sensor 115, and a connector 57.

The first current cutoff device 53A, the first set battery 60A, and the current sensor 54 are connected in series via the power lines 55P and 55N. The power line 55P is a power line that connects the external terminal 51 of the positive electrode and the positive electrode of the first set battery 60A. The power line 55N is a power line that connects the external terminal 52 of the negative electrode and the negative electrode of the first set battery 60A. The first current cutoff device 53A is located on the positive electrode side of the first set battery 60A and is provided on the power line 55P on the positive electrode side. The current sensor 54 is located on the negative electrode side of the first set battery 60A and is provided on the power line 55N of the negative electrode.

The first current cutoff device 53A can be configured by a contact switch (mechanical type) such as a relay or a semiconductor switch such as a FET or a transistor. By the OPEN of the first current cutoff device 53A, the first battery 50A is disconnected from the power line 37 of the vehicle 10 and the current is cut off. The first battery 50B is connected to the power line 37 by the CLOSE of the first current cutoff device 53A, and is in a state where power can be supplied to the vehicle 10.

The current sensor 54 measures the current I [A] of the first set battery 60A. The temperature sensor 115 is a contact type or a non-contact type, and measures the temperature [° C.] of the first set battery 60A.

The first management device 100A is provided in the circuit board unit 65. The first management device 100A includes a voltage detection circuit 110 and a processing unit 120. The voltage detection circuit 110 is connected to both ends of each secondary battery 62 by a signal line, and measures the battery voltage V [V] of each secondary battery 62 and the total voltage VB of the first set battery 60A. The total voltage VB [V] of the first set battery 60A is the total voltage of the four secondary batteries 62 connected in series.

The processing unit 120 includes a CPU 121 having a calculation function, a memory 123 as a storage unit, and a communication unit 125. From the outputs of the current sensor 54, the voltage detection circuit 110, and the temperature sensor 115, the processing unit 120 determines the current I of the first set battery 60A, the voltage V of each secondary battery 62, the total voltage VB of the first set battery 60A, and the temperature. To monitor.

The memory 123 is a non-volatile storage medium such as a flash memory or EEPROM. The memory 123 stores a monitoring program for monitoring the state of the first set battery 60A and data necessary for executing the monitoring program. The connector 57 is provided to connect the first battery 50A to the vehicle ECU 31.

As shown in FIG. 4, the first battery 50A includes an accommodating body 71. The housing 71 includes a main body 73 made of a synthetic resin material and a lid 74. The main body 73 has a bottomed tubular shape. The main body 73 includes a bottom surface portion 75 and four side surface portions 76. An upper opening 77 is formed at the upper end portion by the four side surface portions 76.

The accommodating body 71 accommodates the first set battery 60A and the circuit board unit 65. The first set battery 60A has 12 secondary batteries 62. The 12 secondary batteries 62 are connected in 3 parallels and 4 in series. The circuit board unit 65 is arranged on the upper part of the first set battery 60A. In the block diagram of FIG. 3, three secondary batteries 62 connected in parallel are represented by one battery symbol.

The lid 74 closes the upper opening 77 of the body 73. An outer peripheral wall 78 is provided around the lid 74. The lid body 74 has a protrusion 79 having a substantially T-shape in a plan view. Of the front portion of the lid 74, the external terminal 51 of the positive electrode is fixed to one corner, and the external terminal 52 of the negative electrode is fixed to the other corner.

As shown in FIGS. 5A and 5B, the secondary battery 62 has an electrode body 83 housed in a rectangular parallelepiped case 82 together with a non-aqueous electrolyte. The secondary battery 62 is, for example, a lithium ion secondary battery. The case 82 has a case body 84 and a lid 85 that closes an opening above the case body 84.

Although not shown in detail, the electrode body 83 is porous between the negative electrode element in which the active material is applied to the base material made of copper foil and the positive electrode element in which the active material is applied to the base material made of aluminum foil. A separator made of a resin film is arranged. All of these are band-shaped, and are wound flat so that they can be accommodated in the case body 84 with the negative electrode element and the positive electrode element displaced from each other on the opposite sides in the width direction with respect to the separator. ..

The positive electrode terminal 87 is connected to the positive electrode element via the positive electrode current collector 86, and the negative electrode terminal 89 is connected to the negative electrode element via the negative electrode current collector 88. The positive electrode current collector 86 and the negative electrode current collector 88 include a flat plate-shaped pedestal portion 90 and leg portions 91 extending from the pedestal portion 90. A through hole is formed in the pedestal portion 90. The leg 91 is connected to a positive electrode element or a negative electrode element. The positive electrode terminal 87 and the negative electrode terminal 89 include a terminal main body portion 92 and a shaft portion 93 protruding downward from the center portion of the lower surface thereof. Among them, the terminal body portion 92 and the shaft portion 93 of the positive electrode terminal 87 are integrally molded of aluminum (single material). In the negative electrode terminal 89, the terminal body portion 92 is made of aluminum and the shaft portion 93 is made of copper, and these are assembled. The terminal main body 92 of the positive electrode terminal 87 and the negative electrode terminal 89 is arranged at both ends of the lid 85 via a gasket 94 made of an insulating material, and is exposed to the outside from the gasket 94.

The lid 85 has a pressure release valve 95. As shown in FIG. 5A, the pressure release valve 95 is located between the positive electrode terminal 87 and the negative electrode terminal 89. When the internal pressure of the case 82 exceeds the limit value, the pressure release valve 95 is opened to reduce the internal pressure of the case 82.

The second battery 50B includes a second set battery 60B, a second current cutoff device 53B, a current sensor 54, a second management device 100B, and a temperature sensor 115, and includes the first battery 50A. It has the same structure.

FIG. 6 shows a charging curve when the secondary battery 62 is charged at a predetermined rate, with the horizontal axis representing time and the vertical axis representing voltage. Va is a threshold voltage (upper limit voltage at which the secondary battery can be safely used) that opens the first current cutoff device 53A and the second current cutoff device 53B, and is 4 V as an example. Vb is a limit voltage at which the secondary battery 62 loses battery performance, and is 5.8V as an example. Vc is the voltage at which the pressure release valve 95 operates, and is 7V as an example. Losing battery performance means that it cannot be charged or discharged. Equation (1) shows the magnitude relationship of Va, Vb, and Vc.

Va <Vb <Vc ... (1)

2. 2. Charge control The first management device 100A monitors the state of the first battery 50A, and when an abnormality such as overcharge or overdischarge occurs in the first battery 50A, the first current cutoff device 53A is opened to generate current. Cut off. By cutting off the current, the safety of the first battery 50A can be ensured.

The second management device 100B also monitors the state of the second battery 50B, and if the second battery 50B has an abnormality such as overcharge or overdischarge, the second current cutoff device 53B is opened to cut off the current.

Since the first battery 50A and the second battery 50B are connected in parallel, even if one of the batteries 50A and 50B is overcharged and the current is cut off, the other battery 50A and 50B can be used in the vehicle 10. It is possible to prepare for power supply due to sudden load fluctuations.

However, if charging continues due to a failure of the alternator or the like even after one of the batteries 50A and 50B is overcharged and the current is cut off, the other battery 50A and 50B will be overcharged when the other battery is overcharged. It is necessary to open the current cutoff devices 53A and 53B of the batteries 50A and 50B. As a result, the current of both the two batteries 50A and 50B is cut off, and the two batteries are separated from the vehicle 10. From the viewpoint of the safety of the vehicle 10, even if the two batteries 50A and 50B are overcharged, it is possible to maintain the connection with the vehicle 10 and secure the time until the vehicle 10 can be safely stopped. desirable. For example, it is preferable to secure a time of about 2 minutes.

When both the first battery 50A and the second battery 50B are overcharged, the power supply system 30 controls both the first current cutoff device 53A and the second current cutoff device 53B to CLOSE. As a result, even after overcharging, the first battery 50A and the second battery 50B are in a state of being connected to the vehicle 10, so that it is possible to prepare for power supply due to a sudden load fluctuation of the vehicle 10.

By CLOSE both the first current cutoff device 53A and the second current cutoff device 53B, when charging continues after overcharging, the charging current can be shared and accepted by the two batteries 50A and 50B. By sharing and accepting the charging current between the two batteries 50A and 50B, the voltage rise of the batteries 50A and 50B becomes slower than when the charging current is received only by one of the batteries 50A and 50B. Therefore, for example, when the use of the battery is continued up to the limit voltage Vb, the time Tab until the batteries 50A and 50B reach the limit voltage Vb from the threshold voltage Va becomes long.

After the two batteries 50A and 50B are overcharged, the time for the batteries 50A and 50B to maintain the connection to the vehicle 10 can be secured, so that the time until the vehicle 10 can make an emergency stop can be secured.

FIG. 7 is a sequence diagram of charge control of the power supply system 30. In FIG. 7, A1 to A8 show the processes executed by the first battery 50A. B1 to B7 indicate processes executed by the second battery 50B, and C1 to C4 indicate processes executed by the vehicle ECU 31.

The first current cutoff device 53A and the second current cutoff device 53B are controlled by the first management device 100A and the second management device 100B, respectively, except when there is an abnormality such as overcharging or overdischarging.

“Ta” indicates a period during which both the first current cutoff device 53A and the second current cutoff device 53B are CLOSEd. “Tb” indicates a period during which the first current cutoff device 53A is OPEN and the second current cutoff device 53B is CLOSE. “Tc” indicates a period during which both the first current cutoff device 53A and the second current cutoff device 53B are CLOSEd.

The power system 30 is activated, for example, when the ignition switch is turned on or the start button is pressed. After starting the power supply system 30, the first management device 100A and the second management device 100B perform a process of monitoring the state of each of the batteries 50A and 50B based on the outputs of the voltage detection circuit 110, the current sensor 54, and the temperature sensor 115. Start (A1, B1). Specifically, the voltage V of each secondary battery 62, the total voltage VB of the assembled batteries 60A and 60B, the current I of the assembled batteries 60A and 60B, and the temperature are monitored. The first management device 100A and the second management device 100B determine the presence or absence of overcharging by comparing the voltage V of each secondary battery 62 with the threshold voltage Va. A1 and B1 correspond to steps for detecting the voltages of the first battery 50A and the second battery 50B.

The first management device 100A and the second management device 100B execute a process of monitoring the state of each of the batteries 50A and 50B at a fixed cycle, and transmit the result to the vehicle ECU 31 (A2, B2).

When the engine of the vehicle 10 is driven, the alternator 23 starts power generation. When the amount of power generated by the alternator 23 is less than the electric load 25, the charging current flows through the two batteries 50A and 50B, and the two batteries 50A and 50B are charged (A3 and B3).

When the voltage of any of the secondary batteries 62 exceeds the threshold voltage Va in the first battery 50A due to charging, the first management device 100A detects overcharging (A4). The threshold voltage Va is 4V as an example. Overcharging may be determined by the total voltage VB of the assembled battery 60A.

When the first management device 100A detects the overcharge, the first management device 100A notifies the vehicle ECU 31 of the overcharge (A5). Upon receiving the notification of overcharge from the first battery 50A, the vehicle ECU 31 notifies the first battery 50A of the OPEN command of the first current cutoff device 53A (C1).

When the first management device 100A receives the OPEN command from the vehicle ECU 31, the first management device 100A OPENs the first current cutoff device 53A (A6). The current of the first battery 50A is cut off by the OPEN of the first current cutoff device 53A. After that, the charging current flows only to the second battery 50B which has a vacant capacity and has not reached overcharging, and the second battery 50B is further charged.

The voltage of the second battery 50B rises due to charging, and when the voltage of any of the secondary batteries 62 exceeds the threshold voltage Va, the second management device 100B detects overcharging (B4). When the second management device 100B detects the overcharge, the second management device 100B notifies the vehicle ECU 31 of the overcharge (B5). Both the first battery 50A and the second battery 50B can exemplify the failure of the alternator 23 as a factor of overcharging.

When the vehicle ECU 31 receives a notification of overcharge from the second battery 50B in addition to the first battery 50A, the vehicle ECU 31 sends a CLOSE command to CLOSE the first current cutoff device 53A to the first battery 50A, and sends a CLOSE command to the second battery 50B. A CLOSE command for maintaining the second current cutoff device 53B as CLOSE is sent to (C2).

Upon receiving the CLOSE command from the vehicle ECU 31, the first management device 100A switches the first current cutoff device 53A from OPEN to CLOSE (A7). Further, when the second management device 100B receives the CLOSE command from the vehicle ECU 31, the second current cutoff device 53B is maintained as the CLOSE (B6).

As a result, after the two batteries 50A and 50B are overcharged, both the first battery 50A and the second battery 50B are connected to the power line 37 of the vehicle 10, so that the vehicle 10 is suddenly charged. It is possible to prepare for power supply due to load fluctuation. Further, when charging is continued after overcharging, the charging current is shared and accepted by the two batteries 50A and 50B.

When the vehicle ECU 31 receives a notification of overcharge from the second battery 50B in addition to the first battery 50A, the vehicle ECU 31 executes a warning process at the same time as a CLOSE command to the batteries 50A and 50B (C3).

The warning process is a process for warning the driver of an emergency stop of the vehicle 10. For example, the vehicle ECU 31 lights an abnormality notification light (not shown) mounted on the vehicle 10. By lighting the abnormality notification light, it is possible to notify the driver of the abnormality of the vehicle 10 and urge the driver to make an emergency stop. A warning sound may be emitted. When overcharging occurs, such as a failure of the alternator 23, it is considered that the behavior of the vehicle 10 is abnormal. In that case, it is difficult for the driver to notice the abnormality notification light, but by prompting the driver to make an emergency stop by voice, it becomes easier for the driver to recognize the abnormality.

When the emergency stop of the vehicle 10 is completed and then the engine of the vehicle 10 (not shown) is stopped, the vehicle ECU that controls the engine tells the vehicle ECU 31 that the vehicle 10 has made an emergency stop and the engine has stopped. Notice. Upon receiving the notification, the vehicle ECU 31 sends an OPEN command to open the first current cutoff device 53A and the second current cutoff device 53B to the batteries 50A and 50B (C4).

When the first management device 100A and the second management device 100B receive the OPEN command from the vehicle ECU 31, they open the first current cutoff device 53A and the second current cutoff device 53B, respectively, to cut off the current (A8, B7). .. By doing so, it is possible to prohibit the use of the first battery 50A and the second battery 50B after the vehicle is stopped urgently.

In the above, an example in which the first battery 50A is overcharged first is shown. Which of the two batteries 50A and 50B is overcharged first depends on how the two batteries 50A and 50B are used. For example, when the SOC of the second battery 50B having redundancy is set higher than that of the first battery 50A, the second battery 50B tends to be overcharged before the first battery 50A, and the second battery 50B When the SOC is set lower than the first battery 50A, the second battery 50B is likely to be overcharged later than the first battery 50A. SOC (state of charge) is the ratio of the remaining capacity to the actual capacity (available capacity) of the battery.

Even if the second battery 50B is overcharged first, the connection with the vehicle 10 is maintained by CLOSE the two current cutoff devices 53A and 53B when the first battery 50A is overcharged. can do. The same applies when the two batteries 50A and 50B are overcharged at the same time.

3. 3. Effect In this method, when both the first battery 50A and the second battery 50B are overcharged, the first current cutoff device 53A and the second current cutoff device 53B are CLOSEd. As a result, even after overcharging, the first battery 50A and the second battery 50B maintain the connection with the vehicle 10, so that it is possible to prepare for the power supply due to the sudden load fluctuation of the vehicle 10.

By CLOSE both the first current cutoff device 53A and the second current cutoff device 53B, when charging continues after overcharging, the charging current can be shared and accepted by the two batteries 50A and 50B. By sharing and accepting the charging current between the two batteries 50A and 50B, the voltage rise of the batteries 50A and 50B becomes slower than when the charging current is received only by one of the batteries 50A and 50B. Therefore, since the time until the secondary battery 62 reaches the limit voltage Vb that loses the battery performance can be secured, the vehicle 10 can be stopped urgently with a sufficient time.

<Embodiment 2>
In the first embodiment, information regarding the states of the batteries 50A and 50B is transmitted from the first battery 50A and the second battery 50B to the vehicle ECU 31. The vehicle ECU 31 grasped the states of the two batteries 50A and 50B, and decided whether to open or CLOSE the first current cutoff device 53A and the second current cutoff device 53B.

In the second embodiment, the vehicle ECU 31 notifies each of the batteries 50A and 50B of the information of the other battery 50A and 50B. Each of the batteries 50A and 50B receives information about the state of the other battery 50A and 50B from the vehicle ECU 31 and determines whether to open or CLOSE the first current cutoff device 53A and the second current cutoff device 53B.

FIG. 8 is a sequence diagram of charge control of the power supply system 30. In FIG. 8, A1 to A8 show the processes executed by the first battery 50A. B1 to B7 indicate processes executed by the second battery 50B, and C5 to C8 indicate processes executed by the vehicle ECU 31. The charge control sequence shown in FIG. 8 differs from the charge control sequence shown in FIG. 7 in the steps C5 to C8.

After starting the power supply system 30, the first management device 100A and the second management device 100B start the process of monitoring the status of the batteries 50A and 50B (A1, B1).

The first management device 100A and the second management device 100B execute a process of monitoring the state of each of the batteries 50A and 50B at a fixed cycle, and transmit the result to the vehicle ECU 31 (A2, B2).

When the voltage of the secondary battery 62 exceeds the threshold voltage Va in the first battery 50A due to charging, the first management device 100A detects overcharging (A4).

When the first management device 100A detects the overcharge, the first management device 100A notifies the vehicle ECU 31 of the overcharge (A5). Upon receiving the overcharge notification from the first battery 50A, the vehicle ECU 31 notifies the first battery 50A that the second battery 50B is not overcharged (C5).

When the first battery 50A receives from the vehicle ECU 31 that the second battery 50B is not overcharged, the first battery 50A OPENs the first current cutoff device 53A (A6). The current of the first battery 50A is cut off by the OPEN of the first current cutoff device 53A. After that, when charging continues, the charging current flows only to the second battery 50B, and the second battery 50B is further charged.

When the voltage of the secondary battery 62 exceeds the threshold voltage Va in the second battery 50B, the second management device 100B detects overcharging (B4). When the second management device 100B detects the overcharge, it notifies the vehicle ECU 31 of the overcharge (B5).

When the vehicle ECU 31 receives a notification of overcharge from the second battery 50B in addition to the first battery 50A, the vehicle ECU 31 notifies each battery 50A and 50B of the state of the other battery 50A and 50B (C6). In this case, the vehicle ECU 31 notifies the first battery 50A that the second battery 50B is overcharged, and notifies the second battery 50A that the first battery 50B is overcharged.

When the first management device 100A receives the information that the second battery 50B from the vehicle ECU 31 is overcharged, the first management device 100A switches the first current cutoff device 53A from OPEN to CLOSE (A7). Further, when the second management device 100B receives the information that the first battery 50A is overcharged from the vehicle ECU 31, the second current cutoff device 53B is maintained in the CLOSE (B6).

As a result, after the two batteries 50A and 50B are overcharged, both the first battery 50A and the second battery 50B are connected to the power line 37 of the vehicle 10, so that the vehicle 10 is suddenly charged. It is possible to prepare for power supply due to load fluctuation. Further, when charging is continued, the charging current is shared and accepted by the two batteries 50A and 50B.

When the vehicle ECU 31 receives a notification of overcharge from the second battery 50B in addition to the first battery 50A, the vehicle ECU 31 notifies the respective batteries 50A and 50B of the status of the other batteries 50A and 50B, and at the same time, performs a warning process. Is executed (C7). The warning process is a process for warning the driver of an emergency stop of the vehicle 10.

When the emergency stop of the vehicle 10 is completed and then the engine is stopped, the vehicle ECU 31 notifies the batteries 50A and 50B that the emergency stop is completed (C8).

When the first management device 100A and the second management device 100B receive the emergency stop completion notification from the vehicle ECU 31, they open the first current cutoff device 53A and the second current cutoff device 53B, respectively, to cut off the current (A8). , B7). By doing so, it is possible to suppress the prohibition of the use of the first battery 50A and the second battery 50B after the emergency stop of the vehicle.

In this way, even with the method of receiving the state of the other batteries 50A and 50B from the vehicle ECU 31, the states of the two batteries 50A and 50B can be grasped by each of the batteries 50A and 50B.

Therefore, when the two batteries 50A and 50B are overcharged in the batteries 50A and 50B, the current cutoff devices 53A and 53B can be CLOSEd to perform the same charge control as in the first embodiment. You can. That is, even after overcharging, by connecting the first battery 50A and the second battery 50B to the vehicle 10, it is possible to prepare for power supply due to a sudden load change to the vehicle 10. Further, by sharing and accepting the charging current after overcharging between the first battery 50B and the second battery 50B, the voltage rise of the batteries 50A and 50B is suppressed, and the secondary battery 62 loses the battery performance limit voltage Vb. It is possible to secure the time to reach.

<Embodiment 3>
As shown in FIG. 9, the power supply system 200 of the third embodiment includes a first battery 50A, a second battery 50B, a vehicle ECU 31, and a DC-DC converter 35. The first battery 50A and the second battery 50B are different from the first and second embodiments in that they do not have a communication function with the vehicle ECU 31.

The first battery 50A and the second battery 50B are connected by a signal line 210, and information regarding the state of the batteries 50A and 50B such as the presence or absence of overcharging is communicated and shared between the batteries. That is, the first battery 50A grasps whether or not the second battery 50B is overcharged, and the second battery 50B grasps whether or not the first battery 50A is overcharged.

Therefore, when the two batteries 50A and 50B are overcharged in the batteries 50A and 50B, the current cutoff devices 53A and 53B are CLOSEd to perform the same charge control as in the first and second embodiments. Can be done.

<Embodiment 4>
In the fourth embodiment, the amount of charging electricity Q [C] charged by each of the batteries 50A and 50B after overcharging is limited. The charge electricity amount Q [C] can be obtained from the charge current I [A] and the charge time t [S].

FIG. 10 is a flowchart of the charging electricity amount Q limiting process. The charging electricity amount Q limiting process is individually executed by each of the batteries 50A and 50B after being overcharged. Hereinafter, the battery 50A will be described as an example.

When the management device 100A switches the first current cutoff device 53A to CLOSE in response to a command from the vehicle ECU 31 after the battery 50A is overcharged, the current sensor for the subsequent period (for example, the period Tc in FIG. 7). From the charging current I and the charging time t measured by 54, the amount of charging electricity Q1 charged per secondary battery is calculated (S11).

The management device 100A compares the calculated charge electric energy Q1 with the critical electric energy Qab (S13). The limit electric energy Qab is an electric energy corresponding to the voltage difference ΔVab between the threshold voltage Va and the limit voltage Vb (see FIG. 6).

The management device 100A maintains the first current cutoff device 53A in CLOSE when the charging electric energy Q1 is equal to or less than the critical electric energy Qab (S13: NO) (S15).

When the charge electric energy Q1 exceeds the limit electric energy Qab (S13: YES), the management device 100A opens the first current cutoff device 53A to cut off the current of the battery 50A (S17).

After the overcharge is reached, by limiting the charge electricity amount Q1 per secondary battery to the limit electricity amount Qab or less, it is possible to charge the secondary battery 62 within the range in which the battery performance can be maintained. ..

<Other embodiments>
The present invention is not limited to the embodiments described above and the drawings, and for example, the following embodiments are also included in the technical scope of the present invention.

(1) In the first embodiment, the assembled batteries 60A and 60B are exemplified as an example of the power storage unit. The power storage unit may be a single cell (one secondary battery 62). The power storage unit is not limited to the secondary battery 62, and may be a power storage element such as a capacitor. Although the DC-DC converter 35 is included in the power supply system 30, the DC-DC converter 35 may not be included. For example, when there is no difference in the usage of the first battery 50A and the second battery 50B, it is less necessary to adjust the charge / discharge of the second battery 50B independently, and the DC-DC converter 35 may be omitted. When there is an adjusting device such as a DC-DC converter 35, the rated voltages of the two batteries 50A and 50B may be the same or different. Further, the threshold voltage Va that opens the first current cutoff device 53A of the first battery 50A and the threshold voltage Va that opens the second current cutoff device 53B of the second battery 50B may be different.

(2) In the first embodiment, the first current cutoff device 53A and the first management device 100A are provided inside the first battery 50A, and the second current cutoff device 53B and the second management device 100B are inside the second battery 50B. It was installed in. The first battery 50A and the second battery 50B need only have at least the assembled batteries 60A and 60B, and the first current cutoff device 53A and the first management device 100A are provided outside the first battery 50A. May be. Similarly, the second current cutoff device 53B and the second management device 100B may be provided outside the second battery 50B.

(3) In the first embodiment, when the emergency stop of the vehicle 10 is completed and the engine is stopped, the first current cutoff device 53A and the second current cutoff device 53B are opened to prohibit the use of the batteries 50A and 50B. .. The timing for prohibiting the use of the batteries 50A and 50B may be after a predetermined period has elapsed from the engine stop. By setting the timing for prohibiting the use of the batteries 50A and 50B after a predetermined time has elapsed from the engine stop, it is possible to secure a time for notifying the outside that the vehicle 10 is in an emergency stop state by lighting the hazard lamp or the like. You can.

(4) As shown in FIG. 11, the first current cutoff device 53A and the second current cutoff device 53B may be FETs (field effect transistors) incorporating a parasitic diode D whose forward direction is the discharge direction (C direction). .. By using FET, it is possible to allow discharge while prohibiting charging.

(5) This technology can be applied to the control program of the power supply system of the vehicle. The control program of the power supply system of the vehicle tells the computer a first current cutoff device that cuts off the current of the first power storage unit and the second power storage unit when both the first power storage unit and the second power storage unit are overcharged. This is a program for executing a process of CLOSE the second current cutoff device that cuts off the current of the unit. This technology can be applied to a recording medium in which a control program of a vehicle power supply system is recorded. The computer is, for example, the vehicle ECU 31.

10 ... Vehicle 21 ... Engine starter (vehicle load)
23 ... Alternator 25 ... Electric load (vehicle load)
30 ... Power supply system 31 ... Vehicle ECU (control unit)
35 ... DC-DC converter 50A, 50B ... 1st battery, 2nd battery 53A, 53B ... 1st current cutoff device, 2nd current cutoff device 60A, 60B ... 1st set battery (1st set battery) 1 storage unit), 2nd set battery (2nd storage unit)
100A, 100B ... 1st management device, 2nd management device

Claims (7)

It is a control method of the power supply system of the vehicle.
The step of detecting the voltage of the first storage unit connected to the vehicle load, and
A step of detecting the voltage of the second storage unit connected in parallel to the first storage unit, and
When both the first power storage unit and the second power storage unit are overcharged, the first current cutoff device that cuts off the current of the first power storage unit and the second current cutoff that cuts off the current of the second power storage unit. A method of controlling a vehicle power system, including a step of CLOSE both of the devices. The method for controlling a vehicle power supply system according to claim 1.
When one of the first storage unit and the second storage unit is overcharged, the current cutoff device of the one storage unit that has reached overcharge is OPEN, and the other that has not reached overcharge. A method of controlling a vehicle power system, including the step of maintaining the current cutoff device of the power storage unit in CLOSE. The method for controlling a vehicle power supply system according to claim 2.
When the other storage unit is overcharged, the current cutoff device of the one storage unit is switched from OPEN to CLOSE, and the current cutoff device of the other storage unit maintains CLOSE. How to control the vehicle's power system, including. The method for controlling a vehicle power supply system according to any one of claims 1 to 3.
A method for controlling a power supply system of a vehicle, which comprises a warning step for requesting the vehicle to stop when both the first power storage unit and the second power storage unit are overcharged. The method for controlling a vehicle power supply system according to claim 4.
When the engine is stopped after the vehicle is stopped, the step includes opening both the first current cutoff device and the second current cutoff device to prohibit the use of the first power storage unit and the second power storage unit. , How to control the vehicle power system. The method for controlling a vehicle power supply system according to any one of claims 1 to 5.
After overcharging, when the charge electricity amount of the first power storage unit or the second power storage unit exceeds the limit electricity amount, the corresponding current cutoff device is opened to cut off the current of the power storage unit exceeding the limit electricity amount. How to control the vehicle's power system, including steps. It ’s a vehicle power system.
The first power storage unit connected to the vehicle load,
A first current cutoff device that cuts off the current of the first power storage unit,
A second storage unit connected in parallel to the first storage unit,
A second current cutoff device that cuts off the current of the second power storage unit,
With a control unit,
The control unit is a vehicle power supply system that CLOSEs both the first current cutoff device and the second current cutoff device when both the first power storage unit and the second power storage unit are overcharged.

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