JP6468104B2 - Power system - Google Patents

Description

  The present invention relates to a power supply system mounted on a vehicle.

  As a power supply system mounted on a vehicle, a configuration for supplying electric power to various on-vehicle electric loads while using a plurality of storage batteries is known.

  In the technique described in Patent Document 1, a power supply system in which two batteries, a main battery and a sub battery, are mounted as a power supply is disclosed. These two batteries are connected in parallel via a relay, a starter and a motor generator are connected to the main battery, and various electric loads that do not allow a voltage drop are connected to the sub-battery.

  With the above configuration, when driving the starter or motor generator, the relay is turned off, and the starter or motor generator is driven in a state where the main battery and the sub battery are electrically disconnected. Thereby, it is suppressed that the voltage fluctuation of the main battery reaches various electric loads connected to the sub battery.

  Further, in Patent Document 1, for the purpose of improving fuel consumption and reducing gas displacement, the engine is stopped when a predetermined stop condition is satisfied, and then the engine is restarted when a predetermined start condition is satisfied. Control is in progress. When the engine is restarted by idling stop control, the motor generator is driven using the power of the main battery.

JP 2013-252765 A

  After the engine is started for the first time by the power supply by the sub battery, when the idling stop control is performed regardless of the deterioration state of the main battery, there is a possibility that the engine is not restarted properly.

  The present invention has been made in view of the above, and provides a power supply system that can appropriately perform idling stop control in a power supply system that supplies electric power to various in-vehicle electric loads while properly using a plurality of storage batteries. Is the main purpose.

  The invention according to claim 1 is applied to a vehicle that automatically stops and restarts an engine in accordance with a predetermined condition, and is connected in parallel to a rotating electrical machine (10) having a power generation function, so that the engine is started for the first time. A first storage battery (11) used for power supply at the time, and a second storage battery (12) used for power supply when restarting after the automatic stop of the engine, An energization determining unit that determines that the second storage battery is in an energized state after a first start of the engine; and an internal resistance of the second storage battery when the second storage battery is in the energized state An internal resistance calculation unit that calculates the power, and a restart determination unit that determines whether or not to allow the restart due to use of power of the second storage battery based on the internal resistance calculated by the internal resistance calculation unit. , Be prepared And wherein the Rukoto.

  According to the first aspect of the present invention, the internal resistance of the second storage battery is calculated in a state where a predetermined current or more is supplied to the second storage battery after the engine is initially started by the first storage battery. And since the electric power supply by the 2nd storage battery is permitted on condition that the internal resistance of the 2nd storage battery is less than a predetermined threshold, restarting the engine appropriately according to the state of the 2nd storage battery Can do.

  According to a second aspect of the present invention, the energization determination unit enters the energized state when a predetermined current or more flows through the second storage battery and a current change amount per unit time at that time is a predetermined value or more. It is characterized by determining that it was.

  According to the second aspect of the present invention, the internal resistance can be calculated with high accuracy by calculating the internal resistance on the condition that the change in the energization current of the second storage battery is steep.

  According to a third aspect of the present invention, the rotating electrical machine performs regenerative power generation when the vehicle decelerates, while performing power assist when the vehicle travels, and the energization determining unit is configured to perform regenerative power generation by the rotating electrical machine. It is determined that the energized state is reached at the start of power or at the start of power assist.

  According to the third aspect of the present invention, the charging / discharging current of the lithium ion storage battery increases at a stroke when regenerative power generation by the rotating electrical machine is started or when power assist is started. By calculating the internal resistance at this time, the internal resistance can be calculated with high accuracy.

  According to a fourth aspect of the present invention, the internal resistance calculation unit performs a process of updating the internal resistance of the second storage battery as the second storage battery enters the energized state after the initial start. It is characterized by.

  According to the fourth aspect of the present invention, after the initial start of the engine, the internal resistance of the second storage battery is updated as the second storage battery is energized. Based on the internal resistance of the two storage battery, it can be determined whether to allow power supply by the second storage battery.

  According to a fifth aspect of the present invention, when it is determined that the internal resistance of the second storage battery is equal to or greater than a predetermined threshold, the power of the first storage battery is reduced when the engine is restarted after automatic stop. It is characterized by comprising a setting unit for setting to use.

  According to invention of Claim 5, when the internal resistance of a 2nd storage battery becomes large, it replaces with a 2nd storage battery and uses the electric power of a 1st storage battery at the time of restart after an engine automatic stop. Therefore, even when the second storage battery is inappropriate for power supply, the engine can be restarted appropriately using the power of the first storage battery.

  The invention according to claim 6 includes a temperature detection unit that detects a temperature of the second storage battery, and a first correction unit that corrects the internal resistance based on a detection result of the temperature. .

  According to invention of Claim 6, the internal resistance of a 2nd storage battery changes according to temperature. Therefore, since the internal resistance is corrected based on the detection result of the temperature of the second storage battery, the internal resistance can be calculated with higher accuracy, and more appropriately whether or not the power supply by the second storage battery is permitted. Can be determined.

  In the seventh aspect of the invention, the energization determining unit determines whether the energization current of the second storage battery is a charge current or a discharge current, and the energization current of the second storage battery is the In the case of a charging current, a second correction unit is provided that corrects the internal resistance to the increase side as compared with the case where the energization current of the second storage battery is the discharge current.

  According to the seventh aspect of the present invention, there is a difference in the internal resistance between the case where the discharge current is supplied to the second storage battery and the case where the charge current is supplied to the second storage battery. In some cases, the internal resistance tends to increase. Also, the detection accuracy of the internal resistance tends to be higher in the discharge current. Therefore, when the charging current is applied to the second storage battery, the internal resistance is corrected to the increase side. In this case, the detection accuracy of the internal resistance when the charging current is supplied to the second storage battery can be increased.

  The invention according to claim 8 is characterized in that an internal resistance when the second storage battery is not used is smaller than an internal resistance when the first storage battery is not used.

  According to the eighth aspect of the present invention, the engine can be restarted more suitably by using the second storage battery having low internal resistance and high acceptability for restarting the engine.

The schematic block diagram of a power supply system. Explanatory drawing of internal resistance calculation. Explanatory drawing of the charging current at the time of internal resistance calculation. The flowchart of the determination process of the decision | availability of execution of idling stop control. The flowchart of the process sequence of idling stop control. The figure which shows correlation with internal resistance and the temperature of a storage battery.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. A vehicle on which the power supply system of this embodiment is mounted travels using an engine (internal combustion engine) as a drive source, and has a so-called idling stop function.

(First embodiment)
As shown in FIG. 1, the power supply system includes a rotating electrical machine 10, a lead storage battery 11, a lithium ion storage battery 12, a starter 13, an electric load 14, a current detection unit 15, a voltage detection unit 16, a first switch 21, and a second switch. 22 and a third switch 23 are provided. Among these, the lithium ion storage battery 12, the 1st switch 21, and the 2nd switch 22 are integrated by being accommodated in the housing | casing (accommodating case) which is not shown in figure, and is comprised as the battery unit U. The lead storage battery 11 corresponds to the first storage battery, and the lithium ion storage battery 12 corresponds to the second storage battery.

  The battery unit U is provided with a first terminal T1 and a second terminal T2 as external terminals. The lead storage battery 11 and the electrical load 14 are connected to the first terminal T1, and the rotating electrical machine 10 and the starter 13 are connected to the second terminal T2. The terminals T1 and T2 are both large current input / output terminals through which input / output currents of the rotating electrical machine 10 flow.

  The rotating shaft of the rotating electrical machine 10 is connected to an engine output shaft (not shown) by a belt or the like, and the rotating shaft of the rotating electrical machine 10 is rotated by the rotation of the engine output shaft, while the rotating shaft of the rotating electrical machine 10 is rotated. As a result, the engine output shaft rotates. In this case, the rotating electrical machine 10 includes a power generation function that generates power (regenerative power generation) by rotating the engine output shaft and the axle, and a power output function that applies rotational force to the engine output shaft. For the rotating electrical machine 10, for example, an ISG (Integrated Starter Generator) is used.

  The lead storage battery 11 and the lithium ion storage battery 12 are electrically connected in parallel to the rotating electrical machine 10, and the storage batteries 11, 12 can be charged by the generated power of the rotating electrical machine 10. The rotating electrical machine 10 is driven by power feeding from the storage batteries 11 and 12.

  The lead storage battery 11 is a well-known general-purpose storage battery. For example, lead dioxide (PbO2) is used for the positive electrode active material of the lead storage battery 11, and lead (Pb) is used for the negative electrode active material. In addition, sulfuric acid (H2SO4) is used as the electrolytic solution. And the lead storage battery 11 is comprised by connecting the some battery cell comprised from these electrodes in series. In the present embodiment, the storage capacity of the lead storage battery 11 is set to be larger than the storage capacity of the lithium ion storage battery 12.

  Compared to the lead storage battery 11, the lithium ion storage battery 12 has a smaller internal resistance in an unused state (new), less power loss during charging / discharging, and higher output density and energy density (high power acceptability). It is a high-density storage battery.

  For example, an oxide containing lithium (lithium metal composite oxide) is used for the positive electrode active material of the lithium ion storage battery 12. Specific examples include LiCoO2, LiMn2O4, LiNiO2, LiFePO4, and the like. As the negative electrode active material of the lithium ion storage battery 12, carbon (C), graphite, lithium titanate (for example, LixTiO2), an alloy containing Si or Su, or the like is used. An organic electrolyte is used as the electrolyte of the lithium ion storage battery 12. And the lithium ion storage battery 12 is comprised by connecting the some battery cell comprised from these electrodes in series.

  In addition, the codes | symbols 11a and 12a in FIG. 1 represent the battery cell assembly of the lead storage battery 11 and the lithium ion storage battery 12, and the codes | symbols 11b and 12b represent the internal resistance of the lead storage battery 11 and the lithium ion storage battery 12. Moreover, in the following description, the open voltage V0 of the storage battery is a voltage generated by the battery cell assemblies 11a and 12a.

  The battery unit U is provided with a first connection path L1 and a second connection path L2 that connect the terminals T1 and T2 and the lithium ion storage battery 12 to each other as an in-unit electrical path. Of these, the first switch 21 is provided in the first connection path L1 that connects the first terminal T1 and the second terminal T2, and the connection point N1 (battery connection point) on the first connection path L1 and the lithium ion storage battery. The second switch 22 is provided in the second connection path L <b> 2 that connects the terminal 12 and the second switch 22.

  For example, the first switch 21 and the second switch 22 are semiconductor switches such as a P-channel MOSFET and an N-channel MOSFET.

  Further, in the present power supply system, a bypass path L <b> 3 that allows the lead storage battery 11 and the rotating electrical machine 10 to be connected without using the first switch 21 is provided. The bypass path L3 bypasses the battery unit U and is connected to the first terminal T1 (path connected to the lead storage battery 11 and the like) and the electrical path connected to the second terminal T2 (to the rotating electrical machine 10). And a path to be connected).

  On the bypass path L3, the 3rd switch 23 which makes the connection between the lead storage battery 11 side and the rotary electric machine 10 side the interruption | blocking state or a conduction | electrical_connection state is provided. For the third switch 23, for example, a normally closed relay switch is used. The bypass path L3 and the third switch 23 can be provided so as to bypass the first switch 21 in the battery unit U.

  The starter 13 is a starting device that starts the engine. When the starter 13 is switched on, the engine is started with electric power supplied from the lead storage battery 11.

  The electric load 14 has a constant voltage required load that is required to be stable so that the voltage of the supplied power is substantially constant or at least varies within a predetermined range, and a general load other than the constant voltage load.

  The electric load 14 will be described in detail. The constant voltage request load includes a travel load related to vehicle travel and a load other than travel. Examples of the driving load include a brake device, an oil pump of an automatic transmission, a fuel pump, and an electric power steering. Examples of loads other than traveling include a navigation device, a display device that displays a meter, an audio device, and the like. The general load is a load that has a relatively wide voltage range that can be operated compared to the constant voltage required load, such as wipers such as headlights and front windshields, blower fans for air conditioners, heaters for defrosters for rear windshields, etc. Is mentioned.

  The current detector 15 is connected in series to the lithium ion storage battery 12 and detects a charge / discharge current flowing through the lithium ion storage battery 12. The voltage detection unit 16 is connected in parallel to the lithium ion storage battery 12 and detects a terminal voltage applied to the lithium ion storage battery 12.

  The rotating electrical machine 10 also serves as a generator that generates electric power using rotational energy of the engine output shaft. Specifically, when the rotor is rotated by the engine output shaft in the rotating electrical machine 10, an alternating current is induced in the stator coil in accordance with the exciting current flowing in the rotor coil, and is converted into a direct current by a rectifier (not shown). Then, the exciting current flowing through the rotor coil in the rotating electrical machine 10 is adjusted by the regulator, so that the voltage of the generated direct current is adjusted to the predetermined voltage V.

  For example, when the vehicle performs steady running or is in an automatic stop state by idling stop control, power is not applied to the engine by driving the rotating electrical machine 10. Further, when the vehicle is assisted in power in an accelerated state or restarted from automatic stop by idling stop control, power is applied to the engine by driving the rotating electrical machine 10.

  The electric power generated by the rotating electrical machine 10 is supplied to the electric load 14 and to the lead storage battery 11 and the lithium ion storage battery 12. When the driving of the engine is stopped and the rotating electrical machine 10 is not generating electric power, electric power is supplied from the lead storage battery 11 and the lithium ion storage battery 12 to the electric load 14. The amount of discharge from the lead storage battery 11 and the lithium ion storage battery 12 to the electric load 14 and the amount of charge from the rotating electrical machine 10 are SOC (State of charge: charge state, the ratio of the actual amount of charge to the amount of charge at full charge). Is appropriately adjusted so as to be in a range in which overcharge / discharge does not occur (SOC usage range).

  The control unit 40 performs various processes in the power supply system. That is, when it is determined that there is an initial start request based on a signal from a starter switch (not shown), the control unit 40 drives the starter 13 to drive the engine.

  At this time, the control unit 40 drives the starter 13 by supplying power from the lead storage battery 11 with the first switch 21 turned on and the second switch 22 turned off. In this case, it is possible to suppress the voltage fluctuation of the lead storage battery 11 caused by the initial start of the engine from reaching the lithium ion storage battery 12 side.

  The control unit 40 performs idling stop control. In the idling stop control, as is well known, the engine is automatically stopped when a predetermined automatic stop condition is satisfied, and the engine is restarted when the predetermined restart condition is satisfied under the automatic stop state. When the engine 40 that has been automatically stopped is restarted, the control unit 40 is rotated by supplying power from the lithium ion storage battery 12 with the first switch 21 turned off and the second switch 22 turned on. The electric machine 10 is driven.

  As described above, in the power supply system including the two power sources of the lead storage battery 11 and the lithium ion storage battery 12, when the engine is started for the first time, the lead storage battery that can output a stable voltage against a large current discharge at the time of the initial start. Is used. On the other hand, when restarting the engine from the engine stop state by idling stop control, by using a lithium ion battery with good charge / discharge characteristics, lead acid battery with low durability against frequent charge / discharge (cumulative charge / discharge) The automatic restart of the engine can be suitably performed using a lithium ion storage battery having good charge / discharge characteristics while suppressing early deterioration.

  By the way, when the lithium ion storage battery 12 is in a deteriorated state, there is a possibility that the power shortage of the lithium ion storage battery 12 may occur. In particular, when the lead-acid battery 11 supplies power when the engine is started for the first time, the idling stop control may be performed even though the lithium-ion battery 12 is in a deteriorated state.

  Therefore, in this embodiment, after the engine is started for the first time, the deterioration state of the lithium ion storage battery 12 is confirmed. Specifically, after the engine is started for the first time, the rotating electrical machine 10 is driven as a generator, and the lithium ion storage battery 12 is energized with a current (charging current) flowing at that time. Then, the internal resistance is calculated as the deterioration state of the lithium ion storage battery 12 from the detection result of the electrical change (current, voltage) of the lithium ion storage battery 12 caused by energization.

  Calculation of the internal resistance of the lithium ion storage battery 12 will be described in detail with reference to FIGS. FIG. 2 is a diagram showing changes in current and voltage of the lithium ion storage battery 12. FIG. 3 is an explanatory diagram of a charge / discharge state.

  In FIG. 2, at time t1, after the engine is started for the first time, power assist is performed by driving the rotating electrical machine 10 as the vehicle accelerates. In this case, as shown in FIG. 3, a large current for driving flows from the lithium ion storage battery 12 to the rotating electrical machine 10. Therefore, at time t1 in FIG. 2, the energization current of the lithium ion storage battery 12 changes sharply toward the discharge side and falls below a predetermined threshold A (discharge current threshold). In the lithium ion storage battery 12, the terminal voltage changes to the decreasing side as the battery is discharged. At this time, since the terminal voltage of the lithium ion storage battery 12 decreases with an inclination depending on the magnitude of the internal resistance of the lithium ion storage battery 12, the internal state of the lithium ion storage battery 12 can be grasped by monitoring the change in the terminal voltage. .

  In the present embodiment, the internal resistance Rs is calculated using the current value detected by the current detection unit 15 and the voltage value detected by the voltage detection unit 16. Specifically, the internal resistance Rs is calculated from the current change amount before and after the sudden change of the energization current and the voltage change amount accompanying the sudden change in current.

  Although illustration is omitted, when power generation of the rotating electrical machine 10 accompanying deceleration deceleration of the vehicle is performed after the initial engine start, a large current for charging from the rotating electrical machine 10 to the lithium ion storage battery 12 Flows. In this case, the energization current of the lithium ion storage battery 12 sharply increases toward the charging side and exceeds a predetermined threshold value (discharge current threshold value). In the lithium ion storage battery 12, the terminal voltage changes to the increasing side with charging. At this time, the internal resistance Rs is calculated using the current value detected by the current detection unit 15 and the voltage value detected by the voltage detection unit 16 as in the case of discharging.

  Then, if the internal resistance Rs is less than the predetermined threshold, the control unit 40 allows the idling stop control thereafter, assuming that the lithium ion storage battery 12 is normal. On the other hand, if the internal resistance Rs is equal to or greater than a predetermined threshold value, it is determined that the lithium ion storage battery 12 is in a deteriorated state, and subsequent idling stop control is prohibited.

  As described above, it is possible to appropriately determine whether or not the idling stop control is performed by detecting the deterioration state (charge state) of the lithium ion storage battery 12 in advance after the engine is started for the first time.

  In addition, after detecting the deterioration state of the lithium ion storage battery 12 after the engine is started for the first time, the deterioration state (internal resistance) of the lithium ion storage battery 12 every time a predetermined or higher charge / discharge current is supplied to the lithium ion storage battery 12. ) Is repeatedly obtained, and the deterioration state (internal resistance) of the lithium ion storage battery 12 is preferably updated each time.

  For example, the internal resistance Rs of the lithium ion storage battery 12 is calculated using a discharge current flowing through the lithium ion storage battery 12 when the engine is restarted. Alternatively, the internal resistance Rs is calculated using the discharge current flowing through the lithium ion storage battery 12 when the rotating electrical machine 10 is driven by the power of the lithium ion storage battery 12. As described above, when the internal resistance Rs is updated every time a predetermined or higher charge / discharge current is supplied to the lithium ion storage battery 12, the idling stop control is performed in a state reflecting the current deterioration state of the lithium ion storage battery 12. The presence or absence of can be determined.

  Next, an execution example of the above process will be described. FIG. 4 is a flowchart of a process for determining whether or not the idling stop control can be executed, and FIG. 5 is a flowchart of a processing procedure of the idling stop control. These processes are repeatedly executed by the ECU 30 in a predetermined cycle under the condition that the starter 13 is turned on and the initial start of the engine has been executed.

  In FIG. 4, it is determined whether or not the lithium ion storage battery 12 is energized (S11). This process can be determined from the current detection result by the current detector 15. When S11 is affirmed, it is determined whether or not the current flowing through the lithium ion storage battery 12 is a large current and is in a sudden change state (S12). This process is affirmed when the energization current of the lithium ion storage battery 12 sharply increases toward the discharge side or the charge side and exceeds a predetermined threshold value (discharge current threshold value or charge current threshold value). Note that S12 may determine whether or not it is the time when the regenerative power generation by the rotating electrical machine 10 is started or when the power assist is started.

  If S12 is affirmed, it is determined whether or not it is before acquisition of the internal resistance Rs (S13). When S13 is affirmed, the internal resistance Rs is calculated from the detection result of the current value and the voltage value of the lithium ion storage battery 12 (S14). Next, it is determined whether or not the internal resistance Rs is less than a predetermined threshold Th (S16). When S16 is affirmed, the permission flag is turned on (S17). On the other hand, when S17 is denied, the permission flag is turned off (S18).

  On the other hand, when S13 is denied, that is, when the internal resistance Rs has been acquired, the internal resistance Rs is updated (S15). For example, the previous value of the internal resistance Rs is updated to the current value of the internal resistance Rs. Alternatively, the current value of the internal resistance Rs may be reflected at a predetermined annealing rate with respect to the previous value of the internal resistance Rs, and the internal resistance Rs may be updated with the value. Then, the process proceeds to S16.

  Next, in FIG. 5, it is determined whether or not the internal resistance Rs of the lithium ion storage battery 12 has been acquired (S31). If S31 is affirmed, it is determined whether or not the idling stop control permission flag is ON (S32). When S32 is affirmed, it is determined whether or not automatic stop by idling stop control is being performed (S33). When S33 is denied, it is determined whether the engine automatic stop condition is satisfied (S34). When S34 is affirmed, the engine is automatically stopped (S35).

  On the other hand, if it is determined in S33 that the engine is being automatically stopped, it is determined whether or not an engine restart condition is satisfied (S36). When S36 is affirmed, the rotary electric machine 10 is driven by the power supply from the lithium ion storage battery 12, and the engine is restarted by the power supplied thereby (S37). In addition, a process is complete | finished when negative determination is carried out by S31, S32, S34, and S35. In these cases, idling stop control is not performed.

  According to the above, the following excellent effects can be achieved.

  A lead storage battery 11 (first storage battery) used for power supply when the engine is started for the first time, and a lithium ion storage battery 12 (second storage battery) used for power supply when restarting after the engine is automatically stopped In the power supply system provided, if the engine is automatically stopped regardless of the internal state of the lithium ion storage battery 12 after the engine is started for the first time by the power supply of the lead storage battery 11, there is a possibility that the engine is not restarted properly. There is. Therefore, after the engine is initially started by the lead storage battery 11, the internal resistance Rs of the lithium ion storage battery 12 is calculated in a state where a predetermined current or more is passed through the lithium ion storage battery 12. The power supply by the lithium ion storage battery 12 is permitted on condition that the internal resistance Rs of the lithium ion storage battery 12 is less than a predetermined threshold. As described above, the engine can be restarted appropriately according to the state of the lithium ion storage battery 12.

  The internal resistance Rs can be calculated with high accuracy by calculating the internal resistance Rs on the condition that the change in the energization current of the lithium ion storage battery 12 is steep.

  -When regenerative power generation by the rotating electrical machine 10 is started or when power assist is started, the charging / discharging current of the lithium ion storage battery 12 increases at a stretch. At this time, the internal resistance Rs can be calculated with high accuracy by calculating the internal resistance Rs.

  Since the internal resistance Rs of the lithium ion storage battery 12 is updated as the lithium ion storage battery 12 is energized after the engine is started for the first time, the internal resistance Rs of the current lithium ion storage battery 12 is Based on the above, it can be determined whether or not the power supply by the lithium ion storage battery 12 is permitted.

  -When the state of charge (SOC) of the battery is low, in a configuration that limits power assist (torque assist) by the rotating electrical machine after engine restart, engine stall may occur due to insufficient output after engine restart . On the other hand, according to the present embodiment, when the internal resistance of the battery is low, idling stop control is prohibited, so that it is possible to suppress inconvenience that power shortage occurs after the engine is restarted.

  -When determining the deterioration state of the battery based on the cumulative travel distance of the vehicle, there is a concern about the influence of the difference in the usage state of the battery. On the other hand, according to the present embodiment, since the internal resistance when the battery is energized is used, the state of the battery can be detected with high accuracy.

  ・ Calculate the integrated amount of charge / discharge current of the battery, and on the condition that the idling stop control is permitted on condition that the integrated amount of charge / discharge current is equal to or greater than the predetermined amount, Until this happens, there may be a disadvantage that idling stop control cannot be permitted. On the other hand, according to the present embodiment, it is possible to determine whether or not the idling stop control can be performed by performing battery energization at least once after the engine is started for the first time.

  ・ Battery voltage drop value and discharge electricity amount that fluctuates according to the deterioration state of the starter, and capacity characteristics that are defined by the discharge electricity amount that is required to rise by a predetermined voltage of the battery that fluctuates according to the deterioration state of the battery Based on this, in the configuration in which the idling stop control permission voltage is changed in order to prevent the engine from being unable to restart after automatic stop, it is assumed that the engine is restarted with the starter. Without this, it is impossible to determine whether or not the idling stop control is permitted. On the other hand, according to the present embodiment, since it is determined whether or not the idling stop control is permitted using the calculated value of the internal resistance of the battery, even when the engine is restarted using the rotating electrical machine 10, the idling stop control is performed. Acceptance / rejection determination can be performed.

  You may change the said embodiment as follows, for example. In addition, in the following description, the same figure number is attached | subjected about the same structure as the above-mentioned structure, and detailed description is abbreviate | omitted.

  In the above, the current flowing through the lithium ion storage battery 12 includes a charging current and a discharging current as described above. It is known that an error occurs in the calculated value of the internal resistance Rs of the lithium ion storage battery 12 depending on whether the current flowing through the lithium ion storage battery 12 is a charging current or a discharging current. That is, the internal resistance Rs calculated at the time of charging current tends to be smaller than that at the time of discharging current.

  Therefore, the internal resistance Rs calculated when the charging current flows through the lithium ion storage battery 12 may be corrected based on the state where the discharge current flows through the lithium ion storage battery 12. For example, the correlation between the current value acquired when the discharge current flows through the lithium ion storage battery 12 and the internal resistance, and the correlation between the current value acquired when the charging current flows and the internal resistance The internal resistance Rs of the lithium ion storage battery 12 acquired when the charging current is applied is corrected. As described above, the internal resistance Rs can be obtained more accurately regardless of the type of charge / discharge current flowing through the lithium ion storage battery 12.

  In the process of FIG. 5 described above, idling stop control may be permitted when the internal resistance Rs of the lithium ion storage battery 12 is equal to or greater than the threshold value. In this case, when the permission flag is OFF in S <b> 32, the rotating electrical machine 10 is driven by the power supply from the lead storage battery 11. As described above, the idling stop control can be appropriately performed even in the deteriorated state of the lithium ion storage battery 12.

  The internal resistance Rs and the temperature T of the lithium ion storage battery 12 have a correlation shown in FIG. Therefore, in FIG. 1, a temperature detection unit that detects the temperature of the lithium ion storage battery 12 may be provided, and the calculated value of the internal resistance Rs may be corrected based on the temperature detection result by the temperature detection unit. That is, the internal resistance Rs is corrected to the decreasing side as the temperature T of the lithium ion storage battery 12 increases. As described above, when the internal resistance Rs is calculated in consideration of the temperature T, the calculation accuracy of the internal resistance Rs can be increased, and thus the idling stop control permission / rejection determination can be performed more appropriately.

  In the above, an example in which the lead storage battery 11 (first storage battery) is used for the initial start of the engine and the lithium ion storage battery 12 (second storage battery) is used when the engine is restarted. In addition to this, when the engine is started for the first time, a storage battery that can output a stable voltage against a large current discharge at the time of the initial start may be used. A high storage battery may be used. For example, a nickel hydride storage battery may be used as the second storage battery. Further, the first storage battery and the second storage battery may be the same type of storage battery.

  In the above description, the internal resistance Rs of the lithium ion storage battery 12 is calculated when regenerative power generation by the rotating electrical machine 10 is started after the engine is started for the first time or when power assist is started. In addition to this, before the start of regenerative power generation by the rotating electrical machine 10 or before the start of power assist, the power generation by the rotating electrical machine 10 is forcibly performed, and the current flowing through the lithium ion storage battery 12 is increased at a time. The resistance Rs may be calculated.

  -In the above, the case where the alternator which has only a power generation function is used as the rotary electric machine 10 among a power generation function and a power output function is assumed. In this case, the internal resistance Rs of the lithium ion storage battery 12 may be calculated using the start of regenerative power generation by the alternator as the rotating electrical machine 10.

  In the above, the calculation result of the internal resistance Rs of the lithium ion storage battery 12 may be used for control other than the idling stop control.

  DESCRIPTION OF SYMBOLS 10 ... Rotary electric machine, 11 ... Lead storage battery, 12 ... Lithium ion storage battery, 15 ... Current detection part, 16 ... Voltage detection part, 40 ... Control part.

Claims (9)

This is applied to a vehicle that automatically stops and restarts an engine according to a predetermined condition, is connected in parallel to a rotating electrical machine (10) having a power generation function, and is used for power supply when the engine is started for the first time. A power storage system comprising a first storage battery (11) and a second storage battery (12) used for power supply at the time of restart after the engine is automatically stopped,
An energization determination unit for determining that the second storage battery is in an energized state after a first start of the engine;
An internal resistance calculator that calculates an internal resistance of the second storage battery when the second storage battery is in the energized state;
Restart determination means for determining whether or not to allow the restart due to the use of electric power of the second storage battery based on the internal resistance calculated by the internal resistance calculation unit;
Equipped with a,
The energization determining unit determines that the energized state has been established when a predetermined current or more flows through the second storage battery and a current change amount per unit time at that time is equal to or greater than a predetermined value. system. The rotating electrical machine generates power while performing power assist when the vehicle is running,
The power supply system according to claim 1, wherein the energization determining unit determines that the energized state has been reached at the start of power generation or at the start of power assist. This is applied to a vehicle that automatically stops and restarts an engine according to a predetermined condition, is connected in parallel to a rotating electrical machine (10) having a power generation function, and is used for power supply at the time of initial engine start. A power storage system comprising a first storage battery (11) and a second storage battery (12) used for power supply at the time of restart after the engine is automatically stopped,
An energization determination unit for determining that the second storage battery is in an energized state after a first start of the engine;
An internal resistance calculator that calculates an internal resistance of the second storage battery when the second storage battery is in the energized state;
Restart determination means for determining whether or not to allow the restart due to the use of electric power of the second storage battery based on the internal resistance calculated by the internal resistance calculation unit;
With
The rotating electrical machine generates power while performing power assist when the vehicle is running,
The power supply system according to claim 1, wherein the power supply determination unit determines that the power supply state has been reached at the start of power generation or power assist. The energization determination unit determines whether the energization current of the second storage battery is a charge current or a discharge current,
When the energization current of the second storage battery is the charging current, a second correction unit is provided that corrects the internal resistance to the increase side compared to the case where the energization current of the second storage battery is the discharge current. The power supply system according to any one of claims 1 to 3 . This is applied to a vehicle that automatically stops and restarts an engine according to a predetermined condition, is connected in parallel to a rotating electrical machine (10) having a power generation function, and is used for power supply at the time of initial engine start. A power storage system comprising a first storage battery (11) and a second storage battery (12) used for power supply at the time of restart after the engine is automatically stopped,
An energization determination unit for determining that the second storage battery is in an energized state after a first start of the engine;
An internal resistance calculator that calculates an internal resistance of the second storage battery when the second storage battery is in the energized state;
Restart determination means for determining whether or not to allow the restart due to the use of electric power of the second storage battery based on the internal resistance calculated by the internal resistance calculation unit;
With
The energization determination unit determines whether the energization current of the second storage battery is a charge current or a discharge current,
When the energization current of the second storage battery is the charging current, a second correction unit that corrects the internal resistance to the increase side as compared to the case where the energization current of the second storage battery is the discharge current is provided. And power system. The internal resistance calculation unit, after the initial start, with the said second battery becomes the conductive state, claims 1 to 5 which comprises carrying out the updating of the internal resistance of the second battery The power supply system according to any one of the above. A setting unit configured to set the power of the first storage battery to be used when restarting after the automatic stop of the engine when it is determined that the internal resistance of the second storage battery is equal to or greater than a predetermined threshold; power system according to any one of claims 1 to 6, characterized in that it comprises. A temperature detector for detecting the temperature of the second storage battery;
A first correction unit for correcting the internal resistance based on the detection result of the temperature;
The power supply system according to any one of claims 1 to 7 , further comprising: The power supply system according to any one of claims 1 to 8 , wherein an internal resistance of the second storage battery when not in use is smaller than an internal resistance of the first storage battery when not in use.

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