JP5533725B2 - Vehicle charging device - Google Patents

Description

The present invention relates to a vehicle for charging various batteries suitably mounted on a vehicle having an electric power source such as EV (Electric Vehicle), HV (hybrid Vehicle), or PHV (Plug-in Hybrid Vehicle). The present invention relates to the technical field of charging devices.

  As similar to this type of device, Patent Literature 1 discloses a cell balance correction device. The cell balance correction device measures a voltage value of each of a plurality of batteries constituting a series battery, compares the measured voltage values, and controls a complementary current that complements the charge / discharge currents of the plurality of batteries. It is said that the voltage difference between a plurality of batteries is eliminated.

  The remaining capacity of each cell is obtained, the cell having the maximum remaining amount Qmax is set as a target cell to be discharged, and the target remaining capacity after discharge of this target cell is set to the average value of the remaining capacity of all cells. A charging control device is also disclosed (see Patent Document 2).

JP 2005-151720 A JP 11-299122 A

  In a battery configured by connecting a plurality of cells in series, there is a variation in capacity (hereinafter, referred to as “capacity imbalance” as appropriate) that occurs mainly between cells. Here, the “capacity” means the maximum charge amount as the physical storage capacity of the cell. When capacity imbalance occurs, the SOC (State Of Charge) defined as the ratio of the actual charge amount to the capacity, etc. : Charge state or its index value) is a factor that varies from cell to cell.

  This SOC is an important index from the viewpoint of preventing overcharge and overdischarge in practical operation. More specifically, for example, a cell that has reached an upper limit value (for example, around 80 to 90%) at which the SOC can be appropriately set should be refrained from further charging, and the SOC should be set appropriately. Charging should be actively promoted for cells that have reached a lower limit value (for example, around 10 to 20%).

  When no control law is established that takes into account such SOC variation (hereinafter referred to as “SOC imbalance” as appropriate), the charge / discharge of the battery is relatively high in SOC among the individual cells. Or it becomes a form bound to a relatively low cell, and it becomes difficult to use a battery efficiently. In addition, temporary overcharge or overdischarge is likely to occur, and the battery is required to have high durability, which is likely to increase costs.

  Here, the voltage of each cell is not necessarily linearly related to the SOC. For example, in an intermediate voltage region sandwiched between certain upper and lower limits, the voltage change relative to the SOC change is not unambiguous and is slow. Therefore, as in the cell balance correction device disclosed in Patent Document 1, even if the charge amount is controlled by comparing the voltage values between the cells, the SOC imbalance generated between the cells is actually sufficient. It will not be resolved. Therefore, it is impossible to avoid various problems such as a decrease in battery utilization efficiency and an increase in battery load as described above.

  On the other hand, since the “remaining capacity” in the charge control device disclosed in Patent Document 2 means the above-described SOC, this device can be expected to eliminate the SOC imbalance. However, in this apparatus, since the relationship between the capacity and the SOC described above is not taken into account, variation in the change speed of the SOC due to the capacity imbalance causes the SOC imbalance. That is, in this apparatus, it is premised that SOC unbalance has occurred originally, and even though the SOC imbalance that has already occurred can be eliminated, the occurrence of SOC imbalance cannot be prevented.

  As described above, the conventional techniques including the devices disclosed in Patent Document 1 and Patent Document 2 sufficiently provide SOC imbalance generated between a plurality of cells in various batteries in which a plurality of cells are connected in series. There is a technical problem that it is difficult to solve.

  This invention is made | formed in view of the technical problem which concerns, and makes it a subject to provide the charging device of the vehicle which can eliminate suitably the SOC imbalance which arises between cells.

In order to solve the above-described problem, a charging device for a first vehicle according to the present invention is a charging device for charging a battery in a vehicle including a battery in which a plurality of cells are connected in series. an external power source, and selectively chargeable charging circuit for each cell in said plurality of cells a power supplied from an external power source, and a cell capacitance specifying means for specifying the capacity of each of said cells, said battery Control means for controlling the charging circuit so that the power is preferentially supplied to a cell having a relatively small specified capacity among the plurality of cells when the battery is in a discharged state. Features.

  Here, the “external power source” according to the present invention refers to all power sources capable of supplying power to the charging device, and preferably an independent energy source such as a solar cell is ideal. However, the power source is not necessarily limited to an energy source independent of the battery. For example, a part of the power from the battery may be supplied to the charging device after voltage conversion and potential separation are performed by the DC-DC converter. .

  The “battery” according to the present invention means a rechargeable power storage device in which a plurality of secondary battery cells such as nickel metal hydride batteries and lithium ion batteries are connected in series. It means a secondary battery having an output voltage of about several hundred volts, in which about a hundred to several hundreds of cells of this type having an output voltage of several volts are connected.

  According to the first vehicle charging apparatus of the present invention, during the operation, the capacity of each of the plurality of cells (that is, the maximum charge amount. Hereinafter, the cell capacity is appropriately referred to as “cell capacity” by the cell capacity specifying means. And the control means performs charge control based on the specified cell capacity. The practical aspect related to “specification” in the present invention includes, for example, detection, calculation, estimation, identification, selection, or acquisition, and is not limited in any way.

  The control means controls the charging circuit so that power is preferentially supplied to a cell having a relatively small specified capacity when the battery is in a discharging state (that is, a state where discharging amount> charging amount). To do.

  Here, “power is preferentially supplied” means that the charge amount is given an advantage, and preferably, the charge start timing in time series precedes others. Can be included. Therefore, various aspects are allowed as a practical aspect in giving an advantage to the charge amount. For example, depending on the specified cell capacity or cell capacity classification (in this case, “depending” means that the cell capacity corresponds to the magnitude of the charge, respectively), It may be changed continuously. Note that such a preferential power supply includes a control mode in which charging is not performed for some cells, but in practice, once or every turn, the capacity of the cell is small or large. It is preferred that some charge be made regardless of

  Note that whether or not a certain cell is a “capacity relatively small” cell may be determined, for example, by comparison with an appropriate reference capacity. For example, when an average cell capacity obtained by averaging the cell capacities for all cells is adopted as this type of reference capacity, a cell having a cell capacity smaller than the average cell capacity indicates that “the capacity is relatively small. May be treated as a cell.

  Therefore, it is possible to prevent a divergence between SOC in a cell having a relatively high charge capacity and a relatively small cell capacity and SOC in a cell having a relatively low charge capacity and a relatively large cell capacity. However, at least the degree can be relaxed. That is, the occurrence of SOC imbalance between cells can be prevented or alleviated, and the battery can be used effectively.

  Here, “SOC” means an index value corresponding to the ratio of the actual charge amount to the capacity. The “charge amount” means a charged amount of electricity or energy. The SOC is normally set to be 100 (%) in the fully charged state of the cell and 0 (%) in the fully discharged state, but as long as it is set or standardized according to a preset rule, There is no limit to its practical aspect.

  By the way, in view of the definition of SOC, the cell capacity affects the amount of change or the rate of change of the SOC of the cell (hereinafter referred to as “cell SOC” as appropriate). Specifically, when the battery is in a discharged state, the amount of change in the cell SOC decreases as the cell capacity increases, and increases as the cell capacity decreases. For this reason, the degree of SOC imbalance occurring between the large capacity cell and the small capacity cell increases as the battery is discharged. In particular, when such a process is followed and a cell having a small cell capacity approaches the SOC region near a complete discharge (for example, SOC = 0 (%)), a sufficient capacity remains in a cell having a relatively large cell capacity. However, from the viewpoint of preventing overdischarge of a cell having a relatively small cell capacity, a situation may arise in which it is necessary to give up further discharge control. When such a situation occurs, the entire capacity of the battery cannot be used effectively.

  For this reason, from the viewpoint of effective use of the battery, a control law that can prevent the occurrence of SOC imbalance itself is necessary, but conventional charging according to a control law that does not take into account the cell capacity at all. The main focus of the control is to eliminate the generated SOC imbalance when the SOC imbalance occurs as a real phenomenon, and it is almost impossible to suppress the occurrence of the SOC imbalance itself. is there.

  In order to overcome the technical problems of various conventional technologies not conceived of such a cell capacity, in the first vehicle charging device according to the present invention, as described above, the control means allows the battery to be discharged. In some cases, the charging circuit is controlled so that power is preferentially supplied to a cell having a relatively small specified capacity. Thereby, as described above, it is possible to prevent or alleviate the occurrence of SOC imbalance between cells.

  The practically beneficial effects achieved by the first vehicle charging apparatus according to the present invention are various effects related to the cancellation of the SOC imbalance that are activated after the occurrence of the SOC imbalance on the premise of the occurrence of the SOC imbalance. It is clearly superior to this measure.

  Note that the cell capacity for each cell can be obtained from the cell SOC and the amount of charge for each cell in a situation where the cell SOC is obtained, for example. In addition, since the cell capacity is unique for each cell generated in the cell manufacturing process or the like, it is substantially unchanged over time as compared with the cell SOC that changes drastically due to power running, regeneration, or the like in the process of running the vehicle. In view of this point, it is also preferable to obtain the cell capacity in advance as a part of the manufacturing process or the subsequent process, and store it as a control parameter in a storage device having a nonvolatile storage area such as a ROM, for example. It is possible. In other words, in the configuration in which the cell SOC is directly controlled, it is necessary to frequently identify the cell SOC in view of the fact that the cell SOC is greatly influenced by the driving conditions of the vehicle and increases and decreases with time. There is. On the other hand, in the present application, which considers whether or not the battery is in a discharged state, the change of the cell SOC itself can be suppressed without waiting for the change of the cell SOC, so that the quick response is excellent. is there.

  As described above, according to the first vehicle charging apparatus of the present invention, it is possible to prevent or alleviate the occurrence of SOC imbalance between cells, and to effectively use the battery. .

In order to solve the above-described problem, a charging device for a second vehicle according to the present invention is a charging device for charging a battery in a vehicle including a battery in which a plurality of cells are connected in series. an external power source, and selectively chargeable charging circuit for each cell in said plurality of cells a power supplied from an external power source, and a cell capacitance specifying means for specifying the capacity of each of said cells, said battery Control means for controlling the charging circuit so that the power is preferentially supplied to a cell having a relatively large specified capacity among the plurality of cells when the battery is in a charged state. Features.

  The charging device for the second vehicle according to the present invention is the same as the charging device for the first vehicle according to the present invention described above except for the configuration of the control means, and has a configuration in which the operation of the control means is different.

  As described above, the cell capacity affects the change amount or change speed of the cell SOC. Specifically, when the battery is in a charged state (that is, a state where the discharge amount <the charge amount), the change amount of the cell SOC decreases as the cell capacity increases, and increases as the cell capacity decreases. For this reason, the degree of SOC imbalance occurring between the large capacity cell and the small capacity cell increases as the battery is charged. In particular, when a cell having a small cell capacity approaches a SOC region near a physical full charge (for example, SOC = 100 (%)) by following such a process, a cell having a relatively large cell capacity has a sufficient capacity. In spite of remaining, there may be a situation where it is necessary to give up further charge control from the viewpoint of preventing overcharge of a cell having a relatively small cell capacity. When such a situation occurs, the entire capacity of the battery cannot be used effectively.

  For this reason, from the viewpoint of effective use of the battery, a control law that can prevent the occurrence of SOC imbalance itself is necessary, but conventional charging according to a control law that does not take into account the cell capacity at all. The main focus of the control is to eliminate the generated SOC imbalance when the SOC imbalance occurs as a real phenomenon, and it is almost impossible to suppress the occurrence of the SOC imbalance itself. is there.

  In order to overcome the technical problems of various conventional technologies not conceived of such cell capacity, in the second vehicle charging device according to the present invention, the control means is specified when the battery is in a charged state. The charging circuit is controlled so that power is preferentially supplied to a cell having a relatively large capacity.

  Note that whether or not a certain cell is a “capacity relatively large” cell may be determined, for example, by comparison with an appropriate reference capacity. For example, when an average cell capacity obtained by averaging the cell capacities for all cells is adopted as this type of reference capacity, a cell having a cell capacity larger than the average cell capacity indicates that “the capacity is relatively large. May be treated as a cell.

  Therefore, it is possible to prevent a divergence between SOC in a cell having a relatively high charge capacity and a relatively small cell capacity and SOC in a cell having a relatively low charge capacity and a relatively large cell capacity. However, at least the degree can be relaxed. That is, the occurrence of SOC imbalance between cells can be prevented or alleviated, and the battery can be used effectively.

  The practically beneficial effects achieved by the second vehicle charging apparatus according to the present invention are various effects related to the cancellation of the SOC imbalance that are activated after the occurrence of the SOC imbalance on the premise of the occurrence of the SOC imbalance. It is clearly superior to this measure.

  The action of the control means related to the charging device of the first vehicle and the action of the control means related to the charging device of the second vehicle are coordinated with each other to suppress the occurrence of SOC imbalance. The effect can be more remarkable.

  In one aspect of the charging device for a first or second vehicle according to the present invention, the control means sets the battery in a charged state based on an estimated value acquired from an external device as an input / output current of the battery. It is determined whether there is a discharge state.

  According to this aspect, the control means estimates the future battery input / output current based on various information obtained from an external device such as a car navigation device, for example, so that the near future battery charge / discharge state Is estimated. Therefore, generation | occurrence | production of future SOC imbalance can be suppressed.

In one aspect of the first or second vehicle charging device according to the present invention, the battery SOC specifying means for specifying the SOC of the battery and the cell SOC specifying means for specifying the SOC of each cell are further provided. And the control means controls the charging circuit so that the power is preferentially supplied to a cell in which the SOC of each of the specified cells is less than the SOC of the specified battery among the plurality of cells. Control.

  According to this aspect, the battery SOC specifying means specifies the battery SOC (that is, the battery SOC), the cell SOC specifying means specifies the cell SOC for each cell, and the specified cell SOC is less than the battery SOC. Power is preferentially supplied to the cell. Therefore, in the case where an SOC imbalance has occurred for some reason despite the measures for preventing the occurrence of the SOC imbalance by the charging device of the first or second vehicle according to the present invention, the cell SOC Using the value itself as a reference value, it is possible to accurately correct the SOC imbalance.

  Here, “SOC of the battery” means the SOC of the entire battery. As a preferred form, the charge amount of the entire battery (the charge of each cell) relative to the capacity of the entire battery (the sum of the capacities of the cells). Mean SOC as a ratio of the sum of the amounts), or an average SOC equivalent value obtained by appropriately correcting the averaged SOC according to various practical requirements. The battery SOC is not necessarily a value that prescribes the state of the battery at that time, but may be a value that prescribes the state of the battery in the future (for example, after several seconds to several minutes). The battery SOC may be specified by a technique such as map matching based on the output voltage, output current, temperature, or the like of the battery or cell, or by various known calculations. Alternatively, when the input / output current of the battery can be grasped, the amount of change in the battery SOC from a certain point in time is estimated from information on various time transitions such as the time integrated value and the time integrated value of the input / output current, The battery SOC may be appropriately used for specifying the battery SOC.

  In practical operation, the control cycle of the charging circuit by the control means is sufficiently fast with respect to the change rate of the SOC promoted by charging in each cell. Therefore, it is rare that the SOC of each cell changes during the execution period of one control cycle. At that point, the SOC imbalance changes in the direction of convergence basically by the action of the control means. .

In one aspect of the charging device of the first or second vehicle according to the present invention including the battery SOC specifying means, based on a deviation between the specified battery SOC and a reference value set for the battery SOC. And a first distribution determining means for determining the distribution of the charge amount for each of the cells , wherein the control means controls the charging circuit so that each of the cells is charged according to the determined distribution. .

  According to this aspect, the distribution of the charge amount for each cell is determined based on the deviation between the battery SOC and the reference value by the action of the first distribution determining means. The control means controls the charging circuit so that the individual cells are sequentially charged according to the determined distribution.

  Here, “distribution of charge amount” broadly includes weighting of the charge amount of each cell in one control cycle when the control means controls the charging circuit, and does not necessarily mean the charge amount itself. (For example, it may be a charging time), but the magnitude relationship between the amounts of charge between cells is uniquely defined by this distribution.

  Therefore, according to this aspect, the SOC imbalance between cells can be corrected more suitably.

  Note that the “reference value” is a fixed or variable value that can be established experimentally, empirically, or theoretically in advance, and it is obvious that limiting the numerical range does not fall within the spirit of the present application. .

  In one aspect of the first or second vehicle charging device according to the present invention including the first distribution determining means, the first distribution determining means includes the specified capacity and the battery in addition to the deviation. The distribution is determined based on an input / output current of the battery related to an input / output of electric power to / from an electric load of the vehicle excluding the external power source.

  The charge / discharge balance of the battery during charging from an external power source is not necessarily zero. In particular, when the vehicle is traveling, for example, discharge control required to power drive an electric load such as a motor, and charge control for absorbing regenerative power from the electric load are required regardless of the scale. There are many cases.

  Here, when the charge / discharge balance of the battery is inclined toward the discharge side as a whole (that is, the relationship of charge amount <discharge amount is established), the rate of decrease in SOC increases as the capacity of the cell decreases. When the balance is inclined to the charging side as a whole (that is, the relationship of charge amount> discharge amount is established), the rate of increase in SOC increases as the capacity of the cell decreases.

  In view of these points, when the battery inputs / outputs electric power to / from the electric load provided in the vehicle, an unexpected large change in the SOC occurs in the future (in the process of running the vehicle). It is a time region that can be reached without delay before, for example, after a few seconds to several minutes, it is more effective to correct the occurrence of SOC imbalance between cells. It is. According to this aspect, in addition to the deviation between the battery SOC and the reference value, the distribution of the charge amount is determined in consideration of the cell capacity and the input / output current of the battery. As a result, it is possible to more effectively correct the SOC imbalance.

  For example, in the case of a vehicle that can predict a near-futuristic travel route of a vehicle, such as a car navigation device, the above-mentioned near future is based on vehicle position information, a set travel route, a destination, or the like. It is also possible to estimate a typical change in the battery SOC. When such a near-future change in the battery SOC is taken into consideration, it is possible to more suitably suppress the occurrence of a future SOC imbalance. Is possible.

In another aspect of the charging device of the first or second vehicle according to the present invention including the battery SOC specifying means, based on a deviation between the SOC of each specified cell and the SOC of the specified battery. The apparatus further comprises second distribution determining means for determining distribution of charge amount for each cell , and the control means controls the charging circuit so that each cell is charged according to the determined distribution.

  According to this aspect, the distribution of the charge amount for each cell is determined according to the deviation between the cell SOC and the battery SOC for each cell by the action of the second distribution determining means. The control means controls the charging circuit so that the individual cells are sequentially charged according to the determined distribution.

  Therefore, according to this aspect, the SOC imbalance that has already occurred can be suitably corrected.

  In one aspect of the charging device of the first or second vehicle according to the present invention including the second distribution determining means, the second distribution determining means includes the specified capacity and the battery in addition to the deviation. The distribution is determined based on an input / output current of the battery related to an input / output of electric power to / from an electric load of the vehicle excluding the external power source.

  According to this aspect, the distribution of the charge amount is determined based on the specified cell capacity and the input / output current of the battery. Therefore, the SOC imbalance that has already occurred can be corrected while predicting future changes in the cell SOC, which is extremely useful in practice.

  At this time, as in the case of the first distribution determination means, it is also possible to use an estimated value acquired from a car navigation device or the like as the input / output current of the battery.

In another aspect of the first or second vehicle charging device according to the present invention including the first or second distribution determining means, the plurality of cells are charged in accordance with the determined distribution. Further, a dividing unit that divides the cells into a plurality of groups is provided, and the control unit controls the charging circuit so that charging is performed for each of the divided groups.

  When the output voltage of the external power supply and the output voltage of each cell are greatly different, for example, a load required for power conversion in a DC-DC converter or the like increases. Such an increase in load leads to power loss, and there is room for improvement from the viewpoint of protecting the charging circuit. In particular, in a battery configured by connecting several hundreds of cells having an output voltage of about several volts in series, the tendency is likely to be remarkable.

  According to this aspect, a plurality of cells are grouped into a plurality of groups by the dividing means, and charging is executed for each group.

  Here, the charge amount of cells belonging to a plurality of groups inevitably increases, and the charge amount of cells not belonging to any group becomes zero. Therefore, if the dividing unit appropriately changes the division pattern of this group, the distribution determined by the determining unit can be realized. That is, it is possible to suppress the SOC imbalance while reducing the power loss when supplying power from the external power source, which is preferable from the viewpoint of efficiently using the battery.

  In another aspect of the charging device for a first or second vehicle according to the present invention, the external power source is a solar battery.

  According to this aspect, since the solar cell is mounted as the external power source, efficient power generation using sunlight is possible, and the battery can be effectively charged. For example, while generating power while the vehicle is parked, the battery is charged, and when appropriate charging is performed, or in synchronization with the return of the driver from the outside of the vehicle, power is supplied from the charged battery as appropriate. Control such as operating an air conditioner is also possible.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

1 is a block diagram conceptually showing a configuration of a vehicle according to a first embodiment of the present invention. FIG. 2 is a circuit diagram conceptually showing a configuration of a charging system in the vehicle of FIG. 1. FIG. 2 is a diagram illustrating a relationship between a battery charge rate SOCmean and a cell charge rate SOCn in the battery provided in the vehicle of FIG. 1. It is another figure which concerns on the effect of 1st Embodiment and illustrates the relationship between a battery charging rate and a cell charging rate. It is a flowchart of the charge control which concerns on 1st Embodiment. It is a flowchart of the charge time determination process in the charge control of FIG. It is a flowchart of the cell capacity estimation process in the charging time determination process of FIG. It is a flowchart of the SOCt determination process in the charge time determination process of FIG. It is a flowchart of the charge process in the charge control of FIG. It is a flowchart of the charge control which concerns on 2nd Embodiment of this invention. It is a flowchart of the distribution ratio determination process in the charge control of FIG. It is a flowchart of the charge process in the charge control of FIG. It is a flowchart of the charge control which concerns on 3rd Embodiment of this invention. 14 is a flowchart of distribution ratio determination processing in the charging control of FIG. 13. It is a circuit diagram which represents notionally the structure of the charging system which concerns on 4th Embodiment of this invention. It is a circuit diagram which represents notionally the structure of the charging system which concerns on 5th Embodiment of this invention. It is a conceptual diagram which illustrates one state of the charging system when the charging process which concerns on 6th Embodiment of this invention is performed. It is a conceptual diagram which illustrates the other state of the charging system when the charging process which concerns on 6th Embodiment of this invention is performed. It is a block diagram showing notionally the composition of the vehicles concerning a 7th embodiment of the present invention. It is a flowchart of the charge control which concerns on 7th Embodiment. It is a flowchart of the distribution ratio determination process in the charge control of FIG. It is a flowchart of the SOCt calculation process in the distribution ratio determination process of FIG. It is a figure showing the relationship between the average vehicle speed v and the running resistance estimated value D in connection with acquisition of the running resistance in the SOCt calculation process of FIG. It is a figure showing the relationship between the estimated output Pmean for vehicle travel, and the estimated engine output Pe in connection with acquisition of the estimated engine output in the SOCt calculation process of FIG.

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram conceptually showing the configuration of the vehicle 10.

  In FIG. 1, a vehicle 10 is a hybrid vehicle that is an example of a “vehicle” according to the present invention, which includes an ECU 100, a hybrid drive device 200, a battery 300, an electric auxiliary machine 400, a solar battery 500, and a charging system 600.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown) and is configured to be able to control the operation of the vehicle 10. The ECU 100 is configured to be able to execute charge control described later in accordance with a control program stored in the ROM.

  Note that the ECU 100 is configured to function as an example of each of the “battery SOC specifying unit”, “cell capacity specifying unit”, and “control unit” according to the present invention in executing the charging control.

  The hybrid drive device 200 is a power train of the vehicle 10. The hybrid drive device 200 includes an engine (not shown) and a plurality of motors as a power source of the vehicle 10, and also has a two-degree-of-freedom differential mechanism for transmitting a drive force supplied from these power sources to a drive shaft. A transmission mechanism including a (planetary gear unit) is provided.

  The hybrid drive device 200 can select a plurality of travel modes, and the vehicle 10 can travel in a travel mode in which the system efficiency is always maximum according to the driving conditions. Under the control of the ECU 100, the hybrid drive apparatus 200 causes the vehicle 10 to travel only with the engine output, causes the vehicle 10 to travel only with the motor output, and makes the engine output and the motor output cooperate with each other. The vehicle 10 can also be run. That is, the vehicle 10 is a so-called series / parallel hybrid vehicle.

  The detailed configuration of the hybrid drive device 200 has a low correlation with the essence of the present invention, and is omitted here for the purpose of preventing the explanation from being complicated. As the configuration of the hybrid drive device 200 and its control mode, Of course, various known modes are applicable. Further, the “vehicle” according to the present invention is not limited to this type of hybrid vehicle, and may be an electric vehicle (EV) that can be driven only by a motor. Alternatively, the power source of the vehicle 10 is only an internal combustion engine as a concept that encompasses an engine that can extract the combustion energy of fuel into kinetic energy and extract it as power (the engine is also a form of the internal combustion engine). It may be.

  The battery 300 has an output voltage of about 300 V, in which N (for example, about N = 200) lithium-ion battery cells CLn (n means a cell number) having an output voltage of 1.5 V inside or outside are connected in series. A high power battery having a voltage. The output voltage Vn (n = 1, 2,..., N) of the cell CLn (n = 1, 2,..., N) of the battery 300 is detected by a voltage sensor or the like (not shown) and is constant by the ECU 100. Or it becomes the structure grasped | ascertained with an indefinite period.

  The electric auxiliary machine 400 is an electric drive type auxiliary machine that operates with power supplied from the battery 300, and refers to, for example, an air conditioner, a power window, or a headlight.

  The solar cell 500 is a solar cell as an example of an “external power source” according to the present invention, in which a plurality of unit cells that generate electromotive force from irradiated light by the photovoltaic effect are connected in series. The external power source according to the present invention is not limited to such a solar cell, and various power sources can be used. However, since the solar cell can generate power by itself using sunlight, it can be mounted on a vehicle. Is suitable as an external power source.

  The charging system 600 is a system configured to charge the battery 300 with the power generated by the solar battery 500. The charging system 600 is electrically connected to the ECU 100, and the operation is controlled by the ECU 100.

  Here, a detailed configuration of the charging system 600 will be described with reference to FIG. FIG. 2 is a block diagram conceptually showing the configuration of the charging system 600. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  2, the charging system 600 includes a DC-DC converter 610, a discharge relay C1, an input ammeter 620, a charging circuit 630, and an output ammeter 640.

  The DC-DC converter 610 is a transformer that steps down the output voltage of the solar cell 500 to a voltage suitable for each cell CLn of the battery 300.

  The input ammeter 620 is a sensor configured to be able to detect the input current Iin of the battery 300. The detected input current Iin is configured to be referred to by the ECU 100 at a constant or indefinite period.

  The charging circuit 630 includes a first relay An (n = 1, 2,..., N) and a second relay Bn (n) connected to each cell CLn (n = 1, 2,..., N). n = 1, 2,..., N), and according to the switching state of each relay, the generated power of the solar battery 500 can be selectively supplied to each cell. It is an example.

  For example, when charging only the cell CL1 with the power generated by the solar battery 500, the ECU 100 controls the first relay A1 and the second relay B1 to be in an on state. As a result, a closed loop including the first relay A1, the cell CL1, the second relay B1, and the discharge relay C1 is formed, and charging of the cell CL1 is realized. The ECU 100 is configured to control the charging time of each cell CLn, that is, the charging amount, by controlling the ON time of the first relay An and the second relay Bn. This control of the charge amount is realized by charge control described later.

  The discharge relay C1 is a relay for discharging the output of the solar cell 500 when the battery 300 is in a charge restriction state, and the terminal is an open-side terminal in the figure (a terminal on the connected side in the figure). The output of the solar cell 500 is consumed by the load resistance indicated by hatching in the figure. In the present embodiment, the discharge relay C1 is basically maintained in the contact state shown in the figure.

<Operation of Embodiment>
The operation of the present embodiment will be described below with reference to the drawings as appropriate.

<Outline of charge control>
First, an outline of charge control executed by the ECU 100 will be described.

  First, the cell charge rate SOCn (n = 1, 2,..., N) in the cell CLn (n = 1, 2,..., N) of the battery 300 will be described with reference to FIG. FIG. 3 is a diagram illustrating the relationship between the battery charge rate SOCmean and the cell charge rate SOCn. The “charge rate” means the ratio of the charge amount (charge amount) to the capacity. The battery charge rate SOCmean is a charge rate averaged over the entire battery 300, and is an example of the “battery SOC” according to the present invention and the “battery SOC” described above. The cell charging rate SOCn is the charging rate of each cell CLn, and is an example of “each SOC” and the above-described “cell SOC” according to the present invention.

  In FIG. 3, the horizontal axis represents the average charging rate SOCmean and the vertical axis represents the output voltage.

  The cells CLn (n = 1, 2,..., N) of the battery 300 have capacity imbalances with each other mainly due to variations in the manufacturing process. Here, in FIG. 3, from the viewpoint of simplifying the description, cell charge rates are illustrated for three types of cells having cell capacities CP1, CP2 (CP1> CP2) and CP3 (CP3 <CP2), respectively. It looks like a solid line, a broken line, and a chain line.

  In particular, when the cells are charged evenly even though capacity imbalance occurs, as shown in the drawing, the cell charge rate also becomes imbalanced (that is, SOC imbalance). For example, in FIG. 3, when the battery charge rate SOCmean is 20 (%), the cell charge rate of the cell having the cell capacity CP1 (ie, the cell having the maximum capacity) is 30 (%) and the cell having the capacity CP3 (ie, the cell having the capacity CP3). The cell charging rate of the cell having the smallest capacity is 5 (%). When the battery charge rate SOCmean is 70 (%), the cell charge rate of the cell with the cell capacity CP1 is 60 (%), and the cell charge rate of the cell with the cell capacity CP3 is 90 (%).

  Such SOC imbalance between cells is not desirable from the viewpoint of stable operation of battery 300 (avoidance of overcharge and overdischarge and reduction of a charge / discharge restriction region). Further, as shown in the figure, as the cell has a relatively small capacity, the sensitivity of the cell charge rate with respect to the charge / discharge amount is high (that is, the change width is large), and the cell charge rate is relatively easily depleted on the discharge side. The charging side tends to be relatively saturated. For this reason, when actually correcting the SOC imbalance, it is necessary to consider the cell capacity.

  As shown in the figure, the output voltage is very slow with respect to the change of the cell charge rate SOCn in the most area of the cell charge rate SOCn. Therefore, when the charge amount is controlled by monitoring the output voltage, it is practically impossible to correct the SOC imbalance between cells. Further, overdischarge in the SOC region close to the complete discharge region (SOC = 5% in FIG. 3) and overcharge in the SOC region close to the full charge region (SOC = 90% in FIG. 3) are prevented. From a viewpoint, it is not desirable that such SOC imbalance occurs.

  In the present embodiment, the charge control executed by the ECU 100 is based on the cell capacity Cn (n = 1, 2,..., N) and the battery charge rate SOCmean. It is the control to suppress. Although the practical control flow of the charge control will be described later, the charge control qualitatively supplies the generated power of the solar cell 500 to a cell having a large capacity when the battery charge rate SOCmean is large, and the battery In the case where the charging rate SOCmean is small, the generated power of the solar battery 500 is preferentially supplied to a small capacity cell.

  Before describing the details of the charge control, the practically beneficial effects achieved by the charge control will be described with reference to FIG. FIG. 4 is another diagram illustrating the relationship between the battery charge rate SOCmean and the cell charge rate SOCn. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof will be omitted as appropriate.

  In FIG. 4, FIG. 4 (a) is a diagram corresponding to a case where a large capacity cell (cell of capacity CP1) is preferentially charged when the battery charge rate SOCmean is high. When the battery charge rate SOCmean is high and charging is performed in preference to the relatively large capacity cell, the increase in the cell charge rate in the small capacity cell (capacity CP3 cell) having a relatively high sensitivity to the charge amount is slow. Thus, the deviation from the cell charge rate in a large-capacity cell having relatively low sensitivity to the charge amount is suppressed. As a result, in FIG. 4A, when the battery charge rate SOCmean is 70 (%), the cell charge rate of the large capacity cell having the capacity CP1 is 65 (%) and the cell charge of the small capacity cell having the capacity CP3. The rate is 75 (%), and the occurrence of the large-scale SOC imbalance as illustrated in FIG. 3 is suppressed.

  Further, in FIG. 4, FIG. 4B is a diagram corresponding to a case where a small capacity cell (a cell having the capacity CO3) is preferentially charged when the battery charge rate SOCmean is low. When the battery charge rate SOCmean is low and charging is performed in preference to a relatively small capacity cell, the cell charge rate declines slowly in a small capacity cell (capacity CP3 cell) that is relatively sensitive to the charge amount. Thus, the deviation from the cell charge rate in a large capacity cell (capacity CP1 cell) having relatively low sensitivity to the charge amount is suppressed. As a result, in FIG. 4B, when the battery charging rate SOCmean = 20 (%), the cell charging rate of the large capacity cell having the capacity CP1 is 25 (%), and the cell charging of the small capacity cell having the capacity CP3 is performed. The rate is 15 (%), and the occurrence of the large-scale SOC imbalance as illustrated in FIG. 3 is suppressed.

<Details of charge control>
Next, details of the charge control according to the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart of the charging control.

  In FIG. 5, the ECU 100 executes a charging time determination process (step S100), and determines the distribution ratio of the charge amount to each cell as the charging time. Thereafter, a charging process is executed (step S200), and charging to each cell is sequentially executed via the drive control of the charging circuit 630 according to the charging time determined by the charging time determination process. Charging control is established by repeating these steps. The execution time (cycle) of one control routine including steps S100 and S200 is sufficiently faster than the rate of change of the battery charge rate SOCmean and the cell charge rate of each cell due to charging.

  Next, the charging time determination process will be described with reference to FIG. FIG. 6 is a flowchart of the charging time determination process.

  In FIG. 6, first, the battery charge rate SOCmean is estimated (step S101). The battery charge rate SOCmean is an averaged SOC (charge rate) in the battery 300, and various estimation methods are known, and therefore the details thereof are omitted here. For example, the battery charge rate SOCmean is an approximate value selected from a map using the output voltage of the battery 300 as a parameter, and a charge / discharge amount (charged positively) obtained by integrating the charge / discharge current value of the battery 300. Based on this, it may be obtained at a constant cycle. In the configuration in which the cell capacity Cn (n = 1, 2,..., N) of each cell is obtained, the battery charge rate SOCmean may be estimated from these and the charge / discharge amount of the battery 300.

  When the battery charge rate SOCmean is estimated, a cell capacity estimation process is further executed (step S300), and then an SOCt determination process is executed (step S400).

  Here, the cell capacity estimation process will be described with reference to FIG. FIG. 7 is a flowchart of the cell capacity estimation process.

  In FIG. 7, the ECU 100 determines whether or not initialization has been completed (step S301). If the initialization is not completed (step S301: NO), the ECU 100 sets the cell capacity Cn (n = 1, 2,..., N) to a preset initial value (step S302). If initialization has been completed (step S301: YES) or if initialization has been executed in step S302, the ECU 100 sets "0" to the counter n and sets the counter to a reset state (step S303). Subsequently, the ECU 100 increments the counter by “1” (step S304). Thereafter, individual processing for the cell defined by the counter n is started.

  The ECU 100 acquires the cell voltage Vn of the nth cell CLn (step S305). Subsequently, the charge amount Qn of the cell CLn is estimated (step S306). Note that the charge amount Qn is a time integral value of the charge / discharge power amount until then, and is a value that the ECU 100 manages while constantly updating.

  Subsequently, the ECU 100 determines whether or not the acquired cell voltage Vn is equal to or lower than the upper limit voltage Vh (step S307). When cell voltage Vn is larger than upper limit voltage Vh (step S307: NO), ECU 100 calculates cell charge rate SOCn in nth cell CLn according to the following equation (1) (step S308).

  Here, SOCh in the equation (1) is an upper limit value (%) of the SOC, and SOCho is a reference value (%) of the upper limit value of the SOC. Each of these is a preset constant.

  When the cell charging rate SOCn is calculated for the nth cell, the ECU 100 defines the following equation (2) defined by the calculated cell charging rate SOCn and the previously obtained charge amount Qn of the nth cell. Thus, the cell capacity Cn is calculated (step S309). When the cell capacity Cn is calculated for the nth cell, the process proceeds to step S314.

  On the other hand, when the acquired cell voltage Vn is equal to or lower than the upper limit voltage Vh in step S307 (step S307: YES), the ECU 100 determines whether or not the cell voltage Vn is equal to or higher than the lower limit voltage Vl (step S310). . When cell voltage Vn is less than lower limit voltage Vl (step S310: NO), ECU 100 calculates cell charge rate SOCn of nth cell CLn according to the following equation (3) (step S311).

  Here, SOCl in the formula (3) is a lower limit value (%) of the SOC, and SOClo is a reference value (%) of the lower limit value of the SOC. Each of these is a preset constant.

  When the cell charging rate SOCn is calculated for the nth cell, the ECU 100 formulas (2) defined by the calculated cell charging rate SOCn and the previously obtained charging amount Qn of the nth cell. Accordingly, the capacitance Cn is calculated (step S312). When the cell capacity Cn is calculated for the nth cell, the process proceeds to step S314.

  On the other hand, if the acquired cell voltage Vn is equal to or higher than the lower limit voltage Vl in step S310 (step S310: YES), that is, the cell voltage Vn is in a voltage region defined by the lower limit voltage Vl and the upper limit voltage Vh. In this case, as illustrated in FIG. 3, the correlation between the voltage and the cell charge rate is ambiguous. Thus, ECU 100 uses the previous updated value as the value of cell capacity Cn for the nth cell, and calculates cell charge rate SOCn for the nth cell according to the following equation (4) (step S313). When step S313 is executed, the process proceeds to step S314.

  In step S314, it is determined whether or not the value of the counter n is equal to or greater than the number N of cells, that is, whether or not the cell capacity Cn and the cell charge rate SOCn have been calculated for all cells. When the counter n is less than N (step S314: NO), the process returns to step S304, and a series of processes is repeated. If the counter n is greater than or equal to N (step S314: YES), the cell capacity estimation process ends. Note that the latest values of the calculated cell capacity Cn and cell charge rate SOCn are always stored in the RAM so that the ECU 100 can refer to them.

  Next, the SOCt determination process will be described with reference to FIG. FIG. 8 is a flowchart of the SOCt determination process. Note that SOCt represents a future change amount of the battery charge rate SOCmean, and serves as a correction factor for more accurately determining the charge amount distribution ratio of each cell in the charge time determination process.

  In FIG. 8, the ECU 100 acquires an input current Iin (step S401). As already described, in this embodiment, the input current Iin supplied from the solar cell 500 to the battery 300 is detected by the input ammeter 620. However, the value of the input current Iin used for determining the battery charge rate change amount SOCt does not necessarily need to be the detected input current Iin itself. For example, it may be a time average value of the input current Iin detected in the past fixed time range. In addition to the detected input current Iin, a fixed value determined in advance may be used. Alternatively, in view of the fact that the external power source is the solar battery 500, the input current Iin used for determining the SOCt may be an estimated value calculated from the amount of solar radiation correlated with time.

  Next, the ECU 100 determines a reference time Δt (step S402). The reference time Δt is a time deviation from the time corresponding to the battery charge rate change amount SOCt. In other words, the battery charge rate change amount SOCt is defined as the change amount of the battery charge rate SOCmean after Δt seconds from that time point. Here, the reference time Δt is a value that can be freely set. However, if the reference time Δt is too small or too large, the practical significance is lowered. Therefore, the solar cell 500 is experimentally, empirically, or theoretically beforehand. Is set to a value that is considered to have some influence on the battery charge rate SOCmean.

For control, the reference time Δt is expressed by the following equation (5). In equation (5), a ₀ (%) is the reference SOC change rate that represents the above-mentioned “some degree of influence”, and Ib (A) is an adjustment constant for adjusting the sensitivity to the input current Iin. It is. These values are determined in advance.

  Next, the ECU 100 acquires the output current Iout of the battery 300 (step S403).

  Note that the output current Iout is an actual value detected by the output ammeter 640, but it is also preferable to use a predicted value in the future in view of the fact that the reference time Δt is a near future time value. When predicting the future output current Iout, for example, based on the difference (elevation difference) between the altitude of the current location and the altitude of the point predicted to arrive after Δt seconds, and the average vehicle speed (movement speed), An average current value after Δt seconds may be predicted. Such prediction of the output current can be realized relatively easily when the vehicle 10 is provided with various car navigation systems as a positioning system using GPS.

  When the output current Iout is acquired, the ECU 100 calculates a battery charge rate change amount SOCt, which is a change amount of the battery charge rate SOCmean after Δt seconds, according to the following equation (6) (step S404). When the battery charge rate change amount SOCt is calculated, the SOCt calculation process ends.

  In addition, the calculation process of said Formula (6) is supplementarily illustrated.

  First, the relationship between the battery charge rate SOCmean and the output current Iout is defined by the following equation (7).

  Here, Cmean in the equation is an average cell capacity that is an average value of the cell capacities Cn, and is defined by the following equation (8) using the cell capacity Cn that has already been obtained in the cell capacity estimation process.

  Next, SOCmean (t + Δt), which is the battery charge rate SOCmean after the reference time Δt seconds, is estimated as shown in the following equation (9) using Taylor expansion related to time.

  Since the second term on the right side of the equation (9) corresponds to the battery charge rate change amount SOCt, the following equation (10) is established.

  As a result, the above equation (6) is derived. Such a calculation method is an example.

  Returning to FIG. 6, when the SOCt calculation process ends, the ECU 100 sets the counter n to “0” and the average charge request value Fmean to “0” as parameter initialization processes (step S102). When the parameter initialization is completed, the counter n is incremented by “1” (step S103), and thereafter the calculation of the charge request value Fn for the nth cell CLn is started. The charge request value Fn is a parameter that gives a weight to the charge time for each cell, and represents a charge request with a positive value.

  ECU 100 calculates charge request value Fn related to cell CLn according to the following equation (11) (step S104). Note that SOCo in the equation is a reference value of the battery charge rate SOCmean and is an example of the “reference value” according to the present invention.

  Here, it supplements about the meaning of (11) Formula. As described above, since the charge request value Fn is a positive value and means a charge request, in order for a certain cell to be charged, the first term and the first term on the right side that are mutually multiplied in the equation (11) All of the two terms must be positive values or negative values.

  In order for the first term on the right side to be a positive value, a value obtained by adding the battery charge rate change amount SOCt to the battery charge rate SOCmean (that is, the near-future battery charge rate SOCmean) is a preset reference value SOCo. It is a condition that it is larger than. In order for the second term on the right side to be a positive value, the cell capacity is required to be larger than the average cell capacity Cmean.

  When these two conditions are combined, when the battery charge rate SOCmean is larger than the reference value “SOCo−SOCt”, or when the battery charge rate “SOCmean + SOCt” including future prediction is larger than the reference value SOCo (these are synonymous) In other words, a cell having a cell capacity larger than the average cell capacity (that is, an example of a “cell having a relatively large capacity” according to the present invention) is charged. Further, the charge amount distribution increases as the absolute value of the deviation of the battery charge rate increases and as the absolute value of the deviation of the cell capacity increases. This is equivalent to the operation of the “first distribution determining unit” according to the present invention.

  On the other hand, in order for the first term on the right side to be a negative value, a value obtained by adding the battery charge rate change amount SOCt to the battery charge rate SOCmean (that is, the near-future battery charge rate SOCmean) is set in advance. The condition is that it is less than the value SOCo. In order for the second term on the right side to be a negative value, the cell capacity is required to be less than the average cell capacity Cmean.

  When these two conditions are combined, when the battery charge rate SOCmean is less than the reference value “SOCo−SOCt”, or when the battery charge rate “SOCmean + SOCt” including the future prediction is less than the reference value SOCo (these are synonymous In other words, a cell having a cell capacity less than the average cell capacity (that is, an example of a “cell having a relatively small capacity” according to the present invention) is charged. Further, the charge amount distribution increases as the absolute value of the deviation of the battery charge rate increases and as the absolute value of the deviation of the cell capacity increases. This is equivalent to the operation of the “first distribution determining unit” according to the present invention.

  Further, from the above equation (6) relating to the definition of the battery charge rate change amount SOCt, when the output current Iout of the battery 300 takes a positive value (that is, the charge / discharge balance is inclined toward the discharge side), the battery charge rate change The quantity SOCt takes a negative value. When the battery charge rate change amount SOCt takes a negative value, the added value of the battery charge rate SOCmean and the battery charge rate change amount SOCt in the equation (11) is difficult to exceed the reference value SOCo. As a result, it is easy to take a negative value, and inevitably preferential charging to a relatively small capacity cell is promoted.

  On the other hand, when the output current Iout of the battery 300 takes a negative value (that is, the charge / discharge balance is inclined toward the charging side), the battery charge rate change amount SOCt takes a positive value. When the battery charge rate change amount SOCt takes a positive value, the added value of the battery charge rate SOCmean and the battery charge rate change amount SOCt in the equation (11) is likely to exceed the reference value SOCo. As a result, it becomes easy to take a positive value, and inevitably preferential charging to a relatively large capacity cell is promoted.

  When the required charging value Fn is calculated, the ECU 100 updates the average required charging value Fmean according to the following equation (12) (step S105). When the average charge request value Fmean is updated, the process proceeds to step S106.

  In step S106, it is determined whether or not the counter n is greater than or equal to N, that is, whether or not the charge request value Fn has been calculated for all cells. If counter n is less than N (step S106: NO), the process returns to step S103, and a series of processes is repeated. If the counter n is greater than or equal to N (step S106: YES), the process proceeds to step S107.

  In step S107, as parameter initialization processing, the counter n is set to “0”, and the average deviation dFmean of the charge request value is set to “0”. When the parameter initialization process ends, the counter n is incremented by “1” (step S108), and the process proceeds to step S109.

  In step S109, the average deviation dFmean of the charge request value is updated according to the following equation (13).

  When the average deviation dFmean of the charge request value is updated, the ECU 100 determines whether or not the counter n is greater than or equal to N, that is, whether or not the charge request value Fn has been calculated for all the cells (step S110). If the counter n is less than N (step S110: NO), the process returns to step S108, and a series of processes is repeated. If the counter n is greater than or equal to N (step S110: YES), the process proceeds to step S111.

  In step S111, as a preparatory process for calculating the charging time, the counter n is set to “0”, and the square root of the average deviation dFmean of the required charging value is newly set as the average deviation dFmean of the required charging value. When the preparation process ends, the counter n is incremented by “1” (step S112), and the process proceeds to step S113.

  In step S113, the ECU 100 determines a charging time Tn for the cell CLn according to the following equation (14). Note that To in the equation is a charging cycle time, which is approximately 10 milliseconds to several seconds. Further, T1 in the equation is a preset charging time adjustment parameter.

  When the charging time Tn for the cell CLn is determined, the ECU 100 determines whether or not the counter n is greater than or equal to N, that is, whether or not the charging time Tn has been calculated for all cells (step S114). If counter n is less than N (step S114: NO), the process returns to step S112, and a series of processes is repeated. When the counter n is greater than or equal to N (step S114: YES), the charging time determination process ends. The charging time of each cell determined in the charging time determination process is used in the subsequent charging process.

  Next, the charging process (step S200) will be described with reference to FIG. FIG. 9 is a flowchart of the charging process.

  In FIG. 9, the ECU 100 sets the relay C1 to the charging side (step S201).

  When relay C1 is set to the charging side, ECU 100 resets counter n (step S202), and then increments counter n by “1” (step S203).

  The ECU 100 turns on the nth first relay An (step S204) and simultaneously turns on the nth second relay Bn (step S205). When both relays are on-controlled, current is supplied to the cell CLn and only the cell CLn is charged.

  The ECU 100 holds this state for the charging time Tn of the cell CLn previously determined (step S206). When the charging time Tn elapses, the ECU 100 controls to turn off the nth first relay An (step S207) and simultaneously controls to turn off the nth second relay Bn (step S208). In this way, charging for the nth cell CLn is completed.

  When the charging for the nth cell is completed, it is determined whether or not the counter n is equal to or greater than N, that is, whether or not charging has been completed for all the cells in one charging cycle (step S209). If the counter n is less than N (step S209: NO), the process returns to step S203, and a series of processes is repeated. If the counter n is greater than or equal to N (step S209: YES), that is, when all the cells are charged in one charging cycle, the charging process ends.

  As described above, according to the charge control according to the present embodiment, when the sum of the battery charge rate SOCmean and the battery charge rate change amount SOCt corresponding to the future change amount is larger than the reference value SOCo, Charging time is preferentially allocated to cells having a large capacity, and when the sum is less than the reference value SOCo, charging time is preferentially allocated to cells having a relatively small capacity.

  Therefore, as illustrated in FIG. 4, charging to each cell can be performed without delay while preventing the occurrence of SOC imbalance between the cells. That is, as a result, the charge / discharge area of the battery 300 can be expanded and its capacity can be used effectively. In addition, since a situation where some cells are overcharged or overdischarged is prevented, the life of the battery 300 can be extended.

In the present embodiment, the cell capacity Cn is estimated based on the cell charge rate SOCn. However, when the cell capacity Cn is acquired, it is not always necessary to estimate the cell charge rate SOCn. The cell capacity Cn is a specific physical property value for each cell, which is mainly determined in the cell manufacturing process. Therefore, the cell capacity Cn can be measured or estimated, for example, after the manufacturing process is completed, before the vehicle is mounted, or after the vehicle is mounted, and before the vehicle is put into actual travel. For this reason, the cell capacity Cn is substantially unchanged as compared with the cell charge rate SOCn, and once obtained, it can be stored as a fixed value in a ROM or the like. In this case, in the previous cell capacity estimation process, it is only necessary to read the value from the ROM, and the control load is alleviated. Further, even if a method of estimating based on the cell charge rate SOCn as in the present embodiment is adopted, the cell capacity Cn remains unchanged over time, so the cell capacity estimation process is performed once. In this case, the cell capacity estimation process becomes unnecessary for a considerably long time. From this point of view, the charge control based on the cell capacity has better responsiveness compared to the SOC imbalance correction measure using the cell charge rate SOCt that is greatly influenced by the operating state of the hybrid drive apparatus 200 as a control parameter. It can be said that it has.
Second Embodiment
Next, charging control according to the second embodiment of the present invention will be described. In the charge control according to the second embodiment, the SOC error generated for some reason depends on the deviation between the cell charge rate SOCn and the battery charge rate SOCmean of each cell of the battery 300, the cell capacity Cn, and the charge / discharge state of the battery 300. This is a control to correct the balance. The charge control according to the second embodiment is not incompatible with the control according to the first embodiment, and is a control that can contribute to the suppression of the SOC imbalance more in cooperation with the charge control according to the first embodiment. .

  The charging control according to the first embodiment prevents the occurrence of SOC imbalance, and the charging control according to the second embodiment corrects the SOC imbalance that has already occurred. The charge control according to the form has a larger effect in practice. However, in the battery 300 mounted on the vehicle 10, the battery charge rate SOCmean and the cell charge rate SOCn change relatively violently according to the traveling conditions of the vehicle 10. Therefore, even if the charge control according to the first embodiment is performed, a corresponding SOC imbalance can occur at a frequency that is not low.

  On the other hand, since the charge control according to the second embodiment is based on the cell charge rate SOCn, the SOC imbalance can be corrected more closely than the charge control according to the first embodiment. Therefore, it can be more effective than the charge control according to the first embodiment when the SOC imbalance once generated is reached.

  Here, with reference to FIG. 10, the detail of the charge control which concerns on 2nd Embodiment is demonstrated. FIG. 10 is a flowchart of the charging control.

  In FIG. 10, the ECU 100 executes a distribution ratio determination process (step S500), and determines the distribution ratio of the charge amount to each cell. When the distribution ratio is determined, a charging process is executed (step S600), and charging of each cell is executed via drive control of the charging circuit 630. Charging control is established by repeating these steps.

  Next, the details of the distribution ratio determination process, which is a subroutine for charge control, will be described with reference to FIG. FIG. 11 is a flowchart of the distribution ratio determination process. In the figure, the same reference numerals are given to the same portions as those in the above-described drawings, and the description thereof will be omitted as appropriate.

  In FIG. 11, ECU 100 estimates battery charge rate SOCmean (step S101), and executes a cell capacity estimation process (step S300). The battery charge rate SOCmean may be estimated after the cell capacity estimation process. In this case, since the cell capacity Cn and the charge amount Qn are estimated for all cells, the ECU 100 can easily obtain the battery charge rate SOCmean from the total capacity and the total charge amount of the battery 300.

  When the cell capacity estimation process ends, the ECU 100 initializes parameters (step S501). Specifically, the counter n, the corrected charge request value integrated value Xint, and the corrected forward transfer request value minimum value Xmin are each set to “0”. When the parameter initialization is completed, the counter n is incremented by “1” (step S502), and thereafter the calculation of the charge amount distribution ratio Sn for the nth cell CLn is started.

  That is, the ECU 100 first determines the current correction value a according to the following equation (15) (step S503).

  When current correction value a is determined, ECU 100 calculates an SOC deviation ΔSOCn according to the following equation (16) (step S504). The SOC deviation ΔSOCn is a value whose positive value indicates a charge request.

  When SOC deviation ΔSOCn is calculated, ECU 100 calculates corrected charging request value Xn according to the following equation (17) (step S505). The corrected charge request value Xn corresponds to the SOC deviation corrected by the cell capacity and the output current of the battery.

  Here, the current correction value a will be described.

  First, the relationship shown in the following formula (18) and the above-described formulas (7) and (8) is established between the charge amounts SOCn and SOCmean and the output current Iout of the battery 300.

  On the other hand, when predicting the future value ΔSOCn (t + Δt) after Δt seconds of the SOC deviation ΔSOCn defined by the above equation (16), the following equation (19) can be applied.

  When the above formula (18) and formula (7) are used for the formula (19), the following formula (20) is obtained.

Finally, the above equations (17) and (15) are calculated from these equations. That is, the (17) the correction charge request value Xn of the formula is in the (16) SOC deviation ΔSOCn calculated by the formula, after a lapse of time to the manifestation of effects of about _{a o} the SOC in the charging by the solar cell 500 Means a value plus a value. Here, the output current Iout detected by the output current sensor 640 is used as the output current Iout, but a predicted value of the future output current may be used instead.

  Returning to the description of FIG. 11, when the corrected charging request value Xn is calculated, the ECU 100 calculates an integrated value Xint of the corrected charging request value according to the following equation (21) (step S506).

  Subsequently, the ECU 100 determines whether or not the corrected charge request value Xn is less than the minimum value Xmin of the corrected charge request value Xn (step S507). If it is less than the minimum value Xmin (step S507: YES), the minimum The value Xmin is set to the corrected charge request value Xn (step S508), and the process proceeds to step S509. On the other hand, if the corrected charge request value Xn is equal to or greater than the minimum value Xmin (step S507: NO), the process directly proceeds to step S509.

  In step S509, it is determined whether or not the counter n is greater than or equal to N, that is, whether or not the corrected charge request value Xn has been calculated for all cells. If the counter n is less than N (step S509: NO), the process returns to step S502, and a series of processes is repeated. If the counter n is greater than or equal to N (step S509: YES), the process proceeds to step S510.

  In step S510, the counter n is reset again, and then the counter n is incremented by “1” again (step S511).

  Next, the ECU 100 calculates the charge amount distribution ratio Sn according to the following equation (22) (step S512). Xb is a distribution ratio adjustment parameter that has a role of preventing division by zero, and is a value experimentally determined in advance.

  When the charge amount distribution ratio Sn is calculated for the cell CLn defined by the counter n, whether or not the counter n is N or more, that is, whether or not the charge amount distribution ratio Sn is calculated for all the cells. It is determined (step S513). If the counter n is less than N (step S513: NO), the process returns to step S511, and a series of processes are repeated. If the counter n is greater than or equal to N (step S513: YES), that is, when the charge amount distribution ratio Sn is determined for all the cells of the battery 300, the distribution ratio determination process ends. The determined charge amount distribution ratio Sn is referred to in the subsequent charging process.

  Next, the charging process will be described with reference to FIG. FIG. 12 is a flowchart of the charging process. In the figure, the same reference numerals are given to the same portions as those in FIG. 9, and the description thereof will be omitted as appropriate.

  In FIG. 12, the ECU 100 resets the counter n (step S202), and then increments the counter n by “1” (step S203).

  Next, the ECU 100 calculates a charging time Tn per cycle for the nth cell CLn according to the following equation (23) (step S601).

  Here, To is the aforementioned charging cycle time. In addition, since the weighting of the charge amount between cells is held by the charge amount distribution ratio Sn, the charge cycle time To does not necessarily need to be a fixed value.

  When the charging time Tn is calculated, the ECU 100 turns on the nth first relay An (step S204) and simultaneously turns on the nth second relay Bn (step S205). When both relays are on-controlled, current is supplied to the cell CLn and only the cell CLn is charged. When the ECU 100 holds this state for the charging time Tn (step S206), it turns off the nth first relay An (step S207), and simultaneously turns off the nth second relay Bn (step S208). In this way, charging for the nth cell is completed.

  When the charging for the nth cell is completed, it is determined whether or not the counter n is equal to or greater than N, that is, whether or not charging has been completed for all the cells in one charging cycle (step S209). If the counter n is less than N (step S209: NO), the process returns to step S203, and a series of processes is repeated. If the counter n is greater than or equal to N (step S209: YES), that is, when all the cells are charged in one charging cycle, the charging process ends.

  As described above, according to the variation correction control according to the present embodiment, charging is performed for each cell in the charging process according to the charge amount distribution ratio Sn determined by the distribution ratio determination process. At this time, the charge amount distribution ratio Sn is preferentially charged in a cell having a smaller SOCn than the SOCmean based on the SOC deviation ΔSOCn which is a deviation between the cell charge rate SOCn and the battery charge rate SOCmean. It is determined. Therefore, it is possible to effectively correct the SOC variation between the cells, and the overcharge and overdischarge of each cell can be prevented, and the operating area of the battery 300 can be expanded.

  Furthermore, in the distribution ratio determination process according to the present embodiment, the charge amount distribution ratio Sn is corrected based on the SOC deviation SOCn, the cell capacity Cn, and the charge / discharge state of the battery 300 (here, the output current Iout). It is calculated based on the corrected charge request value Xn. More specifically, in consideration of the fact that the size of the cell capacity corresponds to the change rate of the cell charge rate SOCCn, if the battery 300 is in a discharged state, taking into account the charge / discharge state of the battery 300 The corrected charge request value Xn is determined so that a large amount of charging is performed on a cell having a small capacity, and so that a large amount of charging is performed on a cell having a large capacity if the battery 300 is in a charged state. That is, when the battery 300 is in a discharged state, the generated power of the solar cell 500 is preferentially supplied to a cell having a small capacity, and when the battery 300 is in a charged state, the solar cell is preferentially given to a cell having a large capacity. 500 generated power is supplied.

Therefore, it is possible to effectively correct the SOC imbalance that has already occurred while suppressing or avoiding the occurrence of a future SOC imbalance. That is, the SOC imbalance between cells becomes more robust with respect to changes in the running state and operating conditions of the vehicle 10, and a battery state suitable for practical operation of the vehicle 10 is more stably ensured.
<Third Embodiment>
The distribution ratio determination process according to the second embodiment is based on the premise that the battery 300 is basically charged to some extent. However, a sufficient effect can be obtained when the capacity imbalance between cells is large (necessarily, the SOC imbalance tends to increase), or when the generated power of the solar cell 500 as an external power source is not sufficient. There may not be. In particular, in the case of an external power source such as the solar cell 500 in which the generated power can change greatly depending on the sunshine conditions and temperature conditions, such a problem is likely to be manifested.

  Here, with reference to FIG. 13, as a third embodiment of the present invention, charge control including a distribution ratio determination process capable of appropriately selecting a cell to be charged will be described from such a viewpoint. FIG. 13 is a flowchart of the charging control according to the third embodiment. In the figure, the same reference numerals are assigned to the same parts as those in FIG. 10, and the description thereof is omitted as appropriate.

  In FIG. 13, the ECU 100 executes a distribution ratio determination process (step S700), and determines a charge amount distribution ratio Sn to which the concept of cell selection is applied. Thereafter, the charging process is executed according to the determined charge amount distribution ratio Sn (step S600).

  Here, with reference to FIG. 14, the distribution ratio determination process according to step S700 will be described. FIG. 14 is a flowchart of the distribution ratio determination process according to the third embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 11, and the description thereof will be omitted as appropriate.

  In FIG. 14, when the cell capacity estimation process ends, the ECU 100 initializes the parameters (step S701). In step S701, the counter n, the minimum value Xmin of the correction charge request value, and the maximum value Xmax of the correction charge request value. Are reset respectively.

  On the other hand, when the corrected charge request value Xn is calculated for each cell (step S505) and steps S507 and S508 are executed, the ECU 100 determines whether or not the calculated corrected charge request value Xn is greater than the maximum value Xmax. In step S702, if the corrected charging request value Xn is larger than the maximum value Xmax (step S702: YES), the corrected charging request value Xn is limited to the maximum value Xmax (step S703). If corrected charge request value Xn is equal to or smaller than maximum value Xmax (step S702: NO) or corrected charge request value Xn is limited to maximum value Xmax, the process proceeds to step S509.

  If it is determined in step S509 that the corrected charge request value Xn has been calculated for all cells (step S509: YES), the ECU 100 resets the counter n and the integrated value Xint of the corrected charge request value (step S509). In step S704, the charging request reference value Xs is calculated according to the following equation (24) (step S705). Note that c and d in the formula are reference values for determining the correction charge amount, and the larger c / d has the meaning that the cell to be charged is limited.

  After calculating the charge request reference value Xs, the ECU 100 increments the counter n by “1” (step S706), and calculates a new corrected charge request value Xdn according to the following equation (25) (step S707).

  Subsequently, the ECU 100 determines whether or not the calculated new correction charge request value Xdn is a negative value (step S708). If it is a negative value (step S708: YES), the new corrected charge request value Xdn is reset to “0” (step S709).

  When the new corrected charge request value Xdn is reset to “0” or the new corrected charge request value Xdn calculated in step S707 is a positive value (step S708: NO), the ECU 100 corrects the correction charge. The integrated value Xint of the required values is calculated according to the following equation (26) (step S710).

  When step S710 is executed, it is determined whether or not the counter n is greater than or equal to N, that is, whether or not the integrated value Xint of the corrected charge request values has been calculated for all the cells in one cycle (step S711). ). If counter n is less than N (step S711: NO), the process returns to step S706, and a series of processes is repeated. If the counter n is greater than or equal to N (step S711: YES), the process proceeds to step S510, and the charge amount distribution ratio Sn is determined for each cell as in the first embodiment (step S512).

As described above, according to the distribution ratio determination process according to the third embodiment, by setting the charging request reference value Xs, it is possible to avoid charging a cell whose corrected charging request value Xn is equal to or less than the charging request reference value Xs. Can do. Therefore, the charge amount distribution ratio Sn that can always be expected to have a certain effect or more can be determined according to the scale of capacity imbalance between cells, the power generation state of the external power supply, etc., which is useful in practice.
<Fourth embodiment>
The configuration of the charging system is not limited to that of the first to third embodiments. Here, a fourth embodiment of the present invention based on such a purpose will be described with reference to FIG. FIG. 15 is a block diagram conceptually showing the structure of the charging system 601 according to the fourth embodiment of the present invention. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof is omitted as appropriate.

  In FIG. 15, the charging system 601 is different from the first and second embodiments in that the charging system 601 includes a charging circuit 631 instead of the charging circuit 630 and further includes a high-voltage DC-DC converter 650.

  The charging circuit 631 is different from the charging circuit 630 in that it includes relays D1 and E1 for simultaneous charging of all cells. That is, when the relays D1 and E1 are on-controlled, all the cells CLn are charged.

Here, the relays D1 and E1 are connected to the DC-DC converter 650. The DC-DC converter 650 is a high-voltage output converter as compared with the DC-DC converter 610 that reduces the output of the solar cell 500 to the equivalent of the output voltage of one cell, and when the generated power of the solar cell 500 is relatively high, etc. The converter specialized for the high voltage side requires less power loss.
<Fifth Embodiment>
The configuration of the charging system is not limited to that of the first to third embodiments. Here, a fifth embodiment of the present invention based on such a purpose will be described with reference to FIG. FIG. 16 is a block diagram conceptually showing the structure of the charging system 602 according to the fifth embodiment of the present invention. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof is omitted as appropriate.

In FIG. 16, charging system 602 is different from charging system 600 in that it includes a DC-DC converter 660. The DC-DC converter 660 is a converter for redistributing the power once stored in the battery 300 to each cell again. That is, in this configuration, in addition to the solar cell 500, the battery 300 functions as a kind of external power source. According to such a configuration, it is possible to correct the SOC imbalance more finely.
<Sixth Embodiment>
The practical aspect of the distribution process according to the charge amount distribution ratio Sn is not limited to the charge process of FIG. Here, with reference to FIG.17 and FIG.18, the other aspect which concerns on distribution of charge amount is demonstrated as 6th Embodiment of this invention. FIG. 17 is a diagram illustrating one state of the charging system 600 when the charging process according to the sixth embodiment is executed. FIG. 18 is a diagram illustrating another state of the charging system 600 when the distribution process according to the sixth embodiment is executed. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof is omitted as appropriate. In FIGS. 17 and 18, only five cells CL1 to CL5 are shown for the purpose of preventing the explanation from becoming complicated, but the configuration of the charging system is the same as that of the first to third embodiments. Suppose there is.

  In FIG. 17, it is assumed that the charge amount distribution ratio of the cell CL3 is twice that of the other cells. In this case, as illustrated in FIG. 17A, the ECU 100 turns on the first relay A1 and the second relay B3. As a result, the cells CL1, CL2, and CL3 are charged. Next, as illustrated in FIG. 17B, the ECU 100 turns on the first relay A3 and the second relay B5. As a result, the cells CL3, CL4 and CL5 are charged. Therefore, in any case, only the cell CL3 to be charged is doubled in charge compared to the others.

  On the other hand, in FIG. 18, it is assumed that only the charge amount distribution ratio of the cell CL3 is zero. In this case, as illustrated in FIG. 18A, the ECU 100 turns on the first relay A1 and the second relay B2. As a result, the cells CL1 and CL2 are charged. Next, as illustrated in FIG. 18B, the ECU 100 turns on the first relay A4 and the second relay B5. As a result, the cells CL4 and CL5 are charged. Therefore, charging is avoided only in the cell CL3 that is not the target of charging in any case.

If the principle illustrated in FIGS. 17 and 18 is applied, the SOC imbalance between cells is corrected by calculating a grouping pattern and its switching pattern that can realize a given charge distribution ratio Sn. be able to.
<Seventh embodiment>
As described in the first and second embodiments, in calculating the charging time or the charge distribution ratio for each cell, the future SOC current is considered in consideration of the future change in the battery charging rate SOCmean and the output current Iout. It is very useful in practice because it can suppress the occurrence of balance. Such a future change in the state of the battery 300 may be estimated based on the output current Iout of the battery 300 at that time. However, if the near-future driving condition of the vehicle 10 can be grasped, it is more accurate. Estimation can be possible. A seventh embodiment of the present invention based on such a purpose will be described.

  First, the configuration of the vehicle 11 according to the seventh embodiment will be described with reference to FIG. FIG. 19 is a block diagram conceptually showing the configuration of the vehicle 11. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  In FIG. 19, a vehicle 11 is different from the vehicle 10 according to the various embodiments described above in that it includes a car navigation device (hereinafter, referred to as “car navigation device” as appropriate) 700.

  The car navigation device 700 is mounted on the vehicle 11, position information of the vehicle 11, road information around the vehicle 11 (road type, road width, number of lanes, speed limit, road shape, etc.), traffic signal information, and surroundings of the vehicle 11. Is a device configured to be able to provide various types of navigation information including information on various facilities installed in the vehicle, traffic jam information, environmental information, and the like to the driver. The car navigation device 700 includes a navigation processing device 710, a GPS antenna 720, a VICS antenna 730, and a display device 740.

  The navigation processing device 710 is a control unit that is electrically connected to the ECU 100 and is controlled by the ECU 100 so that the entire operation of the car navigation device 700 can be controlled. The navigation processing device 710 is configured to analyze data acquired via the GPS antenna 720 and the VICS antenna 730 and to supply necessary data to the ECU 100, and to provide various navigation information to the display device 740 described later. Can be displayed.

  The GPS antenna 720 is a communication unit configured to be able to receive a GPS signal supplied from a GPS satellite. The GPS signal obtained via the GPS antenna 720 is appropriately converted into position data of the vehicle 11 that can be referred to by the ECU 100 by the navigation processing device 710.

  The VICS antenna 730 is a road-to-vehicle communication means configured to be able to acquire data related to VICS information including road information, traffic signal information, and traffic jam information from various known radio wave beacons and optical beacons installed as infrastructure equipment on the road. is there. Data relating to the VICS information obtained via the VICS antenna 730 is appropriately converted by the navigation processing device 710 into travel route data of the vehicle 11 that can be referred to by the ECU 100.

  The display device 740 is a liquid crystal display device installed on the front console panel of the vehicle 11, for example. The display device 740 is configured to be able to display the various navigation information described above as visual information (that is, image information) to the driver according to the drive control of the navigation processing device 710.

  Charging control in the vehicle 11 having such a configuration will be described with reference to FIG. FIG. 20 is a flowchart of the charging control according to the seventh embodiment. In the figure, the same reference numerals are assigned to the same parts as those in FIG. 10, and the description thereof is omitted as appropriate.

  In FIG. 20, the ECU 100 executes a distribution ratio determination process (step S800) and determines the charge amount distribution ratio Sn. Thereafter, the charging process is executed according to the determined charge amount distribution ratio Sn (step S600).

  Here, with reference to FIG. 21, the distribution ratio determination processing according to the seventh embodiment will be described. FIG. 21 is a flowchart of the distribution ratio determination process according to the seventh embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 11, and the description thereof will be omitted as appropriate.

  In FIG. 21, when the cell capacity estimation process ends (step S300), the ECU 100 executes an SOCt calculation process (step S900). Similar to the SOCt determination process according to the first embodiment, the SOCt calculation process calculates the battery charge rate change amount SOCt, which means the change amount of the battery charge rate SOCmean after Δt seconds (the above-described reference time) from the present time. It is processing to do.

  Here, the SOCt calculation process will be described in detail with reference to FIG. FIG. 22 is a flowchart of the SOCt calculation process.

  In FIG. 22, the ECU 100 acquires auxiliary machine power consumption Ph that is power consumption of the electric auxiliary machine 400 (step S901). Moreover, the average vehicle speed v of the vehicle 11 is acquired (step S902). Furthermore, the running resistance estimated value D of the vehicle 11 is acquired (step S903). At this time, the auxiliary power consumption Ph is selected from a power consumption map in which the operating state of the electric auxiliary machine 400 and the auxiliary power consumption Ph are associated with each other. The average vehicle speed v is an average value of vehicle speeds in a past fixed period, and is obtained by time-processing the vehicle speed.

  On the other hand, the running resistance estimated value D is acquired by referring to a running resistance map in which the average vehicle speed v and the running resistance estimated value D are associated in advance. Here, the running resistance map will be described with reference to FIG. FIG. 23 is a diagram showing the relationship between the average vehicle speed v and the running resistance estimation value D.

  In FIG. 23, the horizontal axis and the vertical axis represent the average vehicle speed v and the running resistance estimated value D, respectively. As shown in the figure, the running resistance estimation value D takes a constant value even when the average vehicle speed v = 0, and increases linearly as the average vehicle speed v increases. In the running resistance map, the relationship illustrated in FIG. 23 is described in numerical form.

  Returning to FIG. 22, when the estimated running resistance value D is acquired, the ECU 100 requests the navigation processing device 710 for data regarding the current altitude ho and the altitude ht after the lapse of Δt seconds (step S904). In response, data provided from the navigation processing device 710 is acquired (step S905).

  When data is acquired from the navigation processing device 710, the ECU 100 determines whether or not the acquired data is valid data (step S906). When the acquired data is not valid data (step S906: NO), the ECU 100 calculates SOCt by another method (step S911).

  The calculation of SOCt by another method means determination of SOCt by the SOCt determination process of FIG. In this case, although the prediction accuracy of the future battery output current Iout is slightly reduced, the concept of predicting the amount of change in the future battery charge rate SOCmean is secured, and the future state of the battery 300 is estimated. Is possible without problems.

When the acquired data is valid data (step S906: YES), the ECU 100 calculates an altitude difference Δh (Δh = ht−ho) (step S907), and according to the following equation (27), an estimated output for vehicle travel Pmean is calculated (step S908). In the equation, m is a vehicle weight (kg), and g is a gravitational acceleration (m / sec ² ).

  Subsequently, the ECU 100 calculates an engine estimated output Pe (step S909).

  Here, the estimated engine output Pe is calculated by acquiring a corresponding value from an engine output map in which the estimated vehicle travel output Pmean and the estimated engine output Pe are associated in advance. Here, the engine output map will be described with reference to FIG. FIG. 24 is a diagram showing the relationship between the vehicle travel estimated output Pmean and the engine estimated output Pe.

  In FIG. 24, the horizontal axis and the vertical axis represent the vehicle travel estimated output Pmean and the engine estimated output Pe, respectively. As shown in the figure, the estimated engine output Pe is zero when the vehicle travel estimated output Pmean is less than a predetermined value, and increases linearly from a certain initial value (> 0) when the estimated value Pmean is greater than or equal to the predetermined value. The estimated engine output Pe is zero when the estimated vehicle travel output Pmean is less than the predetermined value. In the region where the output required to drive the vehicle is relatively low, the motor power is not used. This is because so-called EV (Electric Vehicle) traveling can be performed by an electrical load such as the above. In the engine output map, the relationship illustrated in FIG. 24 is described in numerical form.

  When engine estimated output Pe is calculated, ECU 100 finally calculates battery charge rate change amount SOCt according to the following equation (28) (step S910). Note that V in the formula is the voltage of the battery 300. When the battery charge rate change amount SOCt is calculated, the SOCt calculation process ends.

  Returning to FIG. 21, when the current correction value a is determined in step S503, the ECU 100 calculates the SOC deviation ΔSOCn (step S801). Here, the SOC deviation ΔSOCn is calculated by replacing SOCmean with SOCmean ′ in the above equation (16). Here, the SOCmean ′ is a value obtained by adding the battery charge rate change SOCt calculated in the SOCt calculation process to the battery charge rate SOCmean (that is, SOCmean ′ = SOCmean + SOCt), and a future battery charge rate. This is the SOC of the entire battery 300 in which a change in the SOCmean is considered in a predictive manner.

  When the SOC deviation ΔSOCn is calculated in step S801, the charge amount distribution ratio Sn is finally calculated as in the second embodiment (step S512), and in the subsequent charging process, the cell CLn according to the charge amount distribution ratio Sn. Are sequentially charged.

  Thus, according to the present embodiment, instead of the battery charge rate SOCmean, the battery charge rate SOCmean ′ based on the future battery charge rate change amount SOCt estimated with high accuracy using the car navigation device 700 is obtained as the SOC. This is used for calculating the deviation ΔSOC. For this reason, it becomes possible to correct the SOC imbalance between cells in the battery 300 more stably.

  Of course, instead of the SOCt determination process in the first embodiment, it is possible to use the prediction of the future battery state (that is, the SOCt calculation process) using the car navigation device 700 illustrated in the present embodiment. .

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. The apparatus is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 100 ... ECU, 200 ... Hybrid drive device, 300 ... Battery, 400 ... Electric auxiliary machine, 500 ... Solar cell (external power supply), 600 ... Charging system, 610 ... DC-DC converter, 630 ... Switching relay circuit , A1 to An: first relay, B1 to Bn: second relay.

Claims (10)

A charging device for charging a battery in a vehicle equipped with a battery in which a plurality of cells are connected in series,
An external power supply,
And selectively chargeable charging circuit for each of the cell power supplied from the external power source in the plurality of cells,
Cell capacity specifying means for specifying the capacity of each cell ;
Control means for controlling the charging circuit so that the power is preferentially supplied to a cell having a relatively small specified capacity among the plurality of cells when the battery is in a discharged state. A vehicle charging device. A charging device for charging a battery in a vehicle equipped with a battery in which a plurality of cells are connected in series,
An external power supply,
And selectively chargeable charging circuit for each of the cell power supplied from the external power source in the plurality of cells,
Cell capacity specifying means for specifying the capacity of each cell ;
Control means for controlling the charging circuit so that the power is preferentially supplied to a cell having a relatively large specified capacity among the plurality of cells when the battery is in a charged state. A vehicle charging device. The said control means determines whether the said battery is in a charge state or a discharge state based on the estimated value acquired from an external device as an input-output current of the said battery. The vehicle charging device described in 1. Battery SOC specifying means for specifying the SOC of the battery;
Cell SOC specifying means for specifying the SOC of each cell ; and
The control means controls the charging circuit so that the power is preferentially supplied to a cell in which the SOC of each specified cell of the plurality of cells is less than the SOC of the specified battery. The vehicle charging device according to any one of claims 1 to 3, wherein A first distribution determining means for determining distribution of the charge amount for each of the cells based on a deviation between the SOC of the specified battery and a reference value set for the SOC of the battery ;
The vehicle charging device according to claim 4, wherein the control unit controls the charging circuit so that each of the cells is charged according to the determined distribution. The first distribution determining means is based on the input / output current of the battery related to the input / output of electric power between the specified capacity and the battery and an electric load of the vehicle excluding the external power source in addition to the deviation. The vehicle charging device according to claim 5, wherein the distribution is determined. A second distribution determining means for determining a distribution of charge amount for each of the cells based on a deviation between the SOC of each of the specified cells and the SOC of the specified battery;
The vehicle charging device according to claim 4, wherein the control unit controls the charging circuit so that each of the cells is charged according to the determined distribution. In addition to the deviation, the second distribution determining means is based on the input / output current of the battery related to the specified capacity and input / output of electric power between the battery and an electric load of the vehicle excluding the external power source. The vehicle charging device according to claim 7, wherein the distribution is determined. Dividing means for dividing the plurality of cells into a plurality of groups so that each of the cells is charged according to the determined distribution;
The vehicle charging device according to any one of claims 5 to 8, wherein the control unit controls the charging circuit so that charging is performed for each of the divided groups. The vehicle external charging apparatus according to any one of claims 1 to 9, wherein the external power source is a solar battery.

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