Patent Publication Number: US-2011074354-A1

Title: Car power source apparatus, and capacity equalizing method for the car power source apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a car power source apparatus with many batteries connected in series to increase output voltage, and to a capacity equalizing method for the car power source apparatus. 
     2. Description of the Related Art 
     To achieve high output, a car power source apparatus has many batteries connected in series to increase the voltage. In this power source apparatus, each of the series-connected batteries is charged by the same charging current and discharged by the same discharging current. Therefore, if all the batteries have exactly the same electrical characteristics, battery voltage and remaining capacity non-uniformity will not occur. However, in actuality, batteries cannot be made with exactly the same electrical characteristics. When charging and discharging is performed repeatedly, disparity in battery electrical characteristics results in voltage and remaining capacity non-uniformities. Further, battery voltage non-uniformity can cause over-charging or over-discharging of a particular battery. To avoid this detrimental effect, a car power source apparatus has been developed that detects the voltage of each battery and eliminates non-uniformities. (Refer to Japanese Laid-Open Patent Publication 2004-31013 and 2004-229391.) 
     As shown in  FIG. 8 , the car power source apparatus cited in JP 2004-31013-A has a plurality of parallel blocks  81   a - 81   d  connected in series as a battery block. When battery block charging capacity is adjusted at the parallel block level, the cell open-circuit voltage of each parallel block is detected by a cell voltage detection section  83 . A depth-of-discharge corresponding to the cell open-circuit voltage for each parallel block is read from pre-stored data representing the depth-of-discharge versus cell open-circuit voltage characteristics. If a parallel block has a depth-of-discharge at or below a set value, battery block capacity adjustment at the parallel block level is prohibited. A necessary prerequisite for use of this method is that parallel-connected battery cells are in-turn connected in series. 
     However, practical configurations also include many battery cells connected in series to form battery units that are in-turn connected in parallel, and the previously described method cannot be applied to this connection scheme. As shown in  FIG. 9  for a car power source apparatus with battery units  10  connected in parallel, when equalization is performed between battery cells  11  in each battery unit  10 , there can be voltage differences between the individual parallel-connected battery units  10 . In this case, when the switch SW connecting each battery unit  10  is closed at the start of vehicle operation, surge currents can flow in response to voltage differences from the high voltage battery units  10  to the lower voltage battery units  10 . In particular, since connection resistance between battery units  10  is low, there is a tendency for the surge currents to be high. With these high surge currents, detrimental effects on the switches and battery cells are a concern. 
     The present invention was developed with the object of correcting these types of prior art drawbacks. Thus, it is a primary object of the present invention to provide a car power source apparatus, and capacity equalizing method for the car power source apparatus with a plurality of battery cells connected in series to form battery units and a plurality of battery units in-turn connected in parallel to form a battery block that can effectively eliminate non-uniformity between battery units. 
     SUMMARY OF THE INVENTION 
     To achieve the object stated above, a car power source apparatus for the first aspect of the present invention can be provided with a plurality of battery units having a plurality of series-connected battery cells, a battery block having a plurality of battery units connected in parallel, a unit switch connected in series with each battery unit, cell voltage detection circuits to detect the cell voltages of the battery cells that make up each battery unit, cell capacity equalizing circuits to suppress variation in the remaining capacities of the battery cells that make up each battery unit based on the cell voltages detected by the cell voltage detection circuits, unit voltage detection circuits to detect unit voltage that is the overall voltage of a battery unit, unit capacity equalizing circuits to suppress variation in the remaining capacities of the battery units based on the unit voltages detected by the unit voltage detection circuits, and a power source controller that controls the cell capacity equalizing circuits to equalize battery cell remaining capacities in each battery unit and subsequently controls the unit capacity equalizing circuits to equalize battery unit remaining capacities over the entire battery block. Accordingly, in a battery block with battery units having series-connected battery cells and with those battery units in-turn connected in parallel, non-uniformities in battery cell remaining capacities and non-uniformities in battery unit remaining capacities can be eliminated. 
     A car power source apparatus for the second aspect of the present invention can be configured to allow the power source controller to receive a start signal from the vehicle-side. When the power source controller detects the start signal from the vehicle-side showing an inactive state, each unit switch is turned OFF and battery cells within each battery unit are equalized by the cell capacity equalizing circuits. As a result, equalization is established at the battery cell level, unit remaining capacity equalization can be independently performed on each battery unit, and the flow of high surge currents in some battery cells at unit equalization can be avoided. 
     In a power source apparatus for the third aspect of the present invention, the power source controller can determine if equalization among the battery cells in each battery unit is necessary based on the battery cell voltages detected by the cell voltage detection circuits. For a battery unit judged to require equalization, the power source controller can issue a cell remaining capacity equalization instruction to the cell capacity equalizing circuit of the applicable battery unit to equalize the remaining capacities of the battery cells in that battery unit. As a result, battery units requiring cell remaining capacity equalization can be selected, and suitable cell remaining capacity equalization can be performed for the applicable battery units. 
     In a power source apparatus for the fourth aspect of the present invention, when completion of cell remaining capacity equalization is detected, the power source controller can determine if equalization among the battery units is necessary based on the battery unit voltages detected by the unit voltage detection circuits. For battery units judged to require equalization, the power source controller can issue unit remaining capacity equalization instructions to the unit capacity equalizing circuits of the applicable battery units to equalize remaining battery capacities among the battery units. As a result, a plurality of battery units requiring unit remaining capacity equalization can be selected, and suitable unit remaining capacity equalization can be performed for the applicable battery units. 
     In a power source apparatus for the fifth aspect of the present invention, the power source controller can detect completion of cell remaining capacity equalization by receiving of an equalization-completed signal from the applicable battery unit. As a result, the time at completion of cell remaining capacity equalization can be reliably communicated to the power source controller. 
     In a power source apparatus for the sixth aspect of the present invention, the power source controller can detect completion of cell remaining capacity equalization based on the battery cell voltages detected by the cell voltage detection circuit. As a result, the time at completion of cell remaining capacity equalization can be appropriately recognized by the power source controller. 
     In a power source apparatus for the seventh aspect of the present invention, the power source controller can detect completion of unit remaining capacity equalization based on the battery unit voltages detected by the unit voltage detection circuit in each battery unit. As a result, the time at completion of unit remaining capacity equalization can be appropriately recognized by the power source controller. 
     A car power source apparatus for the eighth aspect of the present invention can be provided with battery block power output terminals, and an output switch connected between the power output terminals and the battery block. When the power source controller receives a key-OFF signal from the vehicle-side, the power source controller can turn the output switch OFF and leave the unit switches ON for a given time period. After the given time period, the power source controller can turn the unit switches OFF. Accordingly, since the series connected batteries are allowed to be connected in parallel for a given time period, unit remaining capacity equalization can take place during that time interval. By performing this operation at the end of driving each time the vehicle is operated, equalization among battery units can be consistently maintained. 
     In a power source apparatus for the ninth aspect of the present invention, the start signal can be the key-ON signal. 
     In a capacity equalizing method for the car power source apparatus for the eleventh aspect of the present invention, the car power source apparatus is provided with a plurality of battery units having a plurality of series-connected battery cells; a battery block having a plurality of battery units connected in parallel; cell voltage detection circuits to detect the cell voltages of the battery cells that make up each battery unit; a unit switch connected in series with each battery unit; unit voltage detection circuits to detect the overall unit voltage of a battery unit; cell capacity equalizing circuits to suppress disparity in the remaining capacities of battery cells that make up each battery unit; unit capacity equalizing circuits to suppress disparity in the remaining capacities of the battery units; and a power source controller that can receive signals from the vehicle-side, controls the cell capacity equalizing circuits to equalize battery cell remaining capacities in each battery unit, and controls the unit capacity equalizing circuits to equalize battery unit remaining capacities over the entire battery block. The capacity equalizing method can include a step to determine if the start signal from the vehicle-side indicates an inactive state, a step to turn all the unit switches OFF when the start signal indicates an inactive state, a step for the power source controller to determine if equalization of the battery cells is necessary in each battery unit based on battery cell voltages detected by the cell voltage detection circuits, a step for applicable cell capacity equalizing circuits to equalize the remaining capacity of each battery cell within the applicable battery units when equalization is determined necessary, a step for the power source controller to determine if cell remaining capacity equalization has been completed for all applicable battery units, a step for the power source controller to determine if equalization between battery units is necessary based on battery unit voltages detected by the unit voltage detection circuits when completion of cell remaining capacity equalization is determined, and a step for applicable unit capacity equalizing circuits to equalize remaining battery capacity between applicable battery units when equalization is determined necessary. 
     As a result, appropriate cell remaining capacity equalization and unit remaining capacity equalization can be performed for battery units that require cell remaining capacity equalization and for battery units that require unit remaining capacity equalization. Further, when equalization is performed, the flow of excessive surge current in the battery cells can be avoided. 
     A capacity equalizing method for the car power source apparatus for the twelfth aspect of the present invention can include a step when the power source controller receives a key-OFF signal from the vehicle-side, the power source controller turns the output switch connected between the power output terminals and the battery block OFF while leaving the unit switches in the ON state for a given time period, and subsequently turns the unit switches OFF after the given time interval. Accordingly, since the series connected batteries are allowed to be connected in parallel for a given time period, unit remaining capacity equalization can take place during that time interval. By performing this operation at the end of driving each time the vehicle is operated, equalization among battery units can be consistently maintained. 
     The above and further objects of the present invention as well as the features thereof will become more apparent from the following detailed description to be made in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing an embodiment of the car power source apparatus; 
         FIG. 2  is a circuit diagram showing an example of a cell capacity equalizing circuit; 
         FIG. 3  is a circuit diagram showing a unit capacity equalizing circuit example; 
         FIG. 4  is a block diagram showing an alternative embodiment of the car power source apparatus; 
         FIG. 5  is a flowchart showing an example of a capacity equalizing method; 
         FIG. 6  is a block diagram showing an example of the power source apparatus installed on-board a hybrid car driven by both an engine and an electric motor; 
         FIG. 7  is a block diagram showing an example of the power source apparatus installed on-board an electric automobile (electric vehicle) driven only by an electric motor; 
         FIG. 8  is a block diagram showing a prior art car power source apparatus having series-connected battery units; 
         FIG. 9  is a block diagram showing a car power source apparatus having battery units connected in parallel; 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     The following describes embodiments of the present invention based on the figures. 
     An embodiment of a car power source apparatus and capacity equalizing method is described based on  FIGS. 1-5 .  FIG. 1  shows a block diagram of an embodiment of a power source apparatus,  FIG. 2  shows a circuit diagram of an example of a cell capacity equalizing circuit,  FIG. 3  shows a circuit diagram for a unit capacity equalizing circuit example of,  FIG. 4  shows a block diagram of an alternative embodiment of a power source apparatus, and  FIG. 5  shows a flowchart of an example of a capacity equalizing method. The car power source apparatus  100  shown in these figures has battery units  10  with a plurality of battery cells  11  that can be charged connected in series to supply power to an electric motor that drives the vehicle. The battery units  10  are configured with a circuit module  12  connected in parallel with each battery unit  10  to farm battery array elements  13 . Further, the power source apparatus  100  has a battery block  15  formed by connecting a plurality of the battery array element  13  battery units  10  in parallel, and a unit switch  16  is connected in series with each battery unit  10 . By selectively turning the unit switches  160 N or OFF, it is possible to disconnect each individual battery unit  10  from the battery block  15 . Suitable circuit breakers and relays (contactors) can be used as the unit switches  16 . 
     Further, the power source apparatus  100  is provided with a power source controller  30  to control the power source apparatus  100 , and battery block  15  power output terminals  50 . The power source controller  30  can receive vehicle key signals from the vehicle-side car controller CC, and can selectively control each circuit module  12  for equalization based on signals from the car controller CC. This power source apparatus  100  makes up the battery system that supplies power to an electric motor that drives the vehicle, and that power is supplied from the power output terminals  50 . 
     [Circuit Modules  12 ] 
     Each circuit module  12  is provided with a cell voltage detection circuit  25  to detect the cell voltages of the battery cells  11  that make up the battery unit  10 , a unit voltage detection circuit  45  to detect the overall voltage of the battery unit  10 , a cell capacity equalizing circuit  20  to suppress variation in the remaining capacities of battery cells  11  that make up the battery unit  10 , and a unit capacity equalizing circuit  40  to suppress variation in the remaining capacities of the battery units  10 , 
     [Battery Block  15 ] 
     A plurality of individual secondary (rechargeable) battery cells  11 , which can be charged and discharged, can be connected in series and parallel and used as a battery block  15 . Batteries such as lithium-ion batteries, nickel-hydride batteries, and nickel-cadmium batteries can be appropriately used as the rechargeable batteries. 
     [Cell Capacity Equalizing Circuit  20 ] 
     Each cell capacity equalizing circuit  20  equalizes battery cell  11  voltages to eliminate non-uniformities. A circuit diagram of one example of a cell capacity equalizing circuit  20  is shown in  FIG. 2 . Here, only one of the three cell capacity equalizing circuits  20  is shown and described below. This cell capacity equalizing circuit  20  discharges high voltage battery cells  11  through cell discharging resistors  22  to eliminate non-uniformities. However, the cell capacity equalizing circuit of the present invention is not limited specifically to a circuit that discharges battery cells through cell discharging resistors. For example, a cell capacity equalizing circuit could also discharge high voltage battery cells into a charge storage device such as a capacitor or battery, and discharge the charge stored in that charge storage device to low voltage battery cells to eliminate battery voltage differences. 
     The cell capacity equalizing circuit  20  of  FIG. 2  is provided with cell discharge circuits  21  having cell switching devices  23  connected in series with the cell discharging resistors  22 . The cell capacity equalizing circuit  20  has a cell control circuit  24  to control each cell switching device  230 N and OFF, and a cell voltage detection circuit  25  connected to detect the voltage of each battery cell  11 . The cell discharging resistor  22  and cell switching device  23  of each cell discharge circuit  21  are connected in parallel with each battery cell  11 . In this cell capacity equalizing circuit  20 , when the voltage of a battery cell  11  becomes high, the cell control circuit  24  switches the cell switching device  23  ON to discharge the battery cell  11  through the cell discharging resistor  22  to reduce the battery cell  11  voltage and equalize battery cells  11 . 
     Further, the cell capacity equalizing circuit  20  operates via power supplied from the battery unit  10 . The cell capacity equalizing circuit  20  of the figure operates off output voltage (Vcc) from a power supply circuit  26  that receives power from the battery unit  10 . For example, battery unit  10  voltage can be stepped-down by a power supply circuit  26  that is a direct-current-to-direct-current (DC-DC) converter to supply power to the cell capacity equalizing circuit  20 . With this circuit configuration, proper operating voltage can be supplied to the cell capacity equalizing circuit  20  even when battery unit  10  voltage is high. 
     The cell voltage detection circuit  25  has input terminals  28  of voltage detection sub-circuits  27  connected to each battery cell  11  to detect the voltage of each battery cell  11 . However, a plurality of battery cell voltages can also be detected with a single voltage detection sub-circuit by providing a switching circuit (not illustrated) at the input-side of the voltage detection sub-circuit to switch the connected battery cell. Output signals from the voltage detection sub-circuits  27  are multiplexed by a multiplexer  29  and input to the cell control circuit  24 . The multiplexer  29  consecutively switches the output from each voltage detection sub-circuit  27  into the cell control circuit  24 . 
     The cell control circuit  24  compares the voltages of the individual battery cells  11 , and controls the cell switching devices  23  to equalize the voltages of all the battery cells  11 . For a battery cell  11  with too high a cell voltage, the cell control circuit  24  switches the cell discharge circuit  21  cell switching device  230 N to discharge that battery cell  11 . Battery cell  11  voltage decreases with discharging. When the battery cell  11  voltage decreases and becomes equal to the voltage of the other battery cells  11 , the cell switching device  23  is switched from ON to OFF. When the cell switching device  23  is turned OFF, discharge of that battery cell  11  stops. In this manner, the cell control circuit  24  discharges high voltage battery cells  11  to equalize the cell voltages of all the battery cells  11 . 
     [Unit Capacity Equalizing Circuit  40 ] 
     A cell capacity equalizing circuit  20  as shown in  FIG. 2  is provided for each of the three battery units  10 A,  106 ,  10 C in the power source apparatus of  FIG. 1  to equalize the battery cells  11  in each battery unit  10 A,  10 B,  10 C. Meanwhile, unit capacity equalizing circuits  40  are provided to eliminate non-uniformities between the battery units  10 .  FIG. 3  shows a unit capacity equalizing circuit  40  example. Here, the three unit capacity equalizing circuits  40  and unit voltage detection circuits  45  shown as circuit module  12  components associated with the three battery units  10 A,  108 ,  10 C in  FIG. 1  are alternately depicted as single distributed circuits in  FIG. 3 . The unit capacity equalizing circuit  40  shown in  FIG. 3  has a unit voltage detection circuit  45  and a unit control circuit  44  connected to the battery block  15 . Further, the unit capacity equalizing circuit  40  is provided with unit discharge circuits  41  having a series-connected unit discharging resistor  42  and unit switching device  43  connected in parallel with each battery unit  10 . The battery units  10  can be equalized via these unit discharge circuits  41 . The total unit voltage is detected for each battery unit  10 , and the unit switching devices  43  of the unit discharge circuits  41  are controlled ON and OFF by the unit control circuit  44 . The unit voltage of each battery unit  10  is detected by the unit voltage detection circuit  45 , and the unit control circuit  44  switches ON the switching device  43  of unit discharge circuits  41  connected to battery units  10  with high unit voltage to discharge those battery units  10  and equalize the battery units  10 . 
     Further, the power source apparatus of  FIG. 1  is provided with a power source controller  30  that controls cell remaining capacity equalization by the cell capacity equalizing circuits  20  and unit remaining capacity equalization by the unit capacity equalizing circuits  40 . The cell capacity equalizing circuits  20  begin equalizing cell remaining capacities in each battery unit  10  upon receipt of a cell remaining capacity equalization signal input from the power source controller  30 . When cell remaining capacity equalization has been completed for all the battery units  10 , next a unit remaining capacity equalization signal is issued from the power source controller  30  to the unit capacity equalizing circuits  40  to begin equalizing remaining capacity between the battery units  10 . The power source controller  30  sets the timing for battery block  15  equalization by the cell capacity equalizing circuits  20  based on vehicle operating conditions and the state of the ignition switch. When it is time for the cell capacity equalizing circuits  20  to perform cell remaining capacity equalization, the power source controller  30  issues a cell remaining capacity equalization signal to the cell capacity equalizing circuits  20 . Conversely, when it is time for the unit capacity equalizing circuits  40  to perform unit remaining capacity equalization, the power source controller  30  issues a unit remaining capacity equalization signal to the unit capacity equalizing circuits  40 . 
     For example, the power source controller  30  detects that the ignition switch is OFF and the vehicle is stopped to output a cell remaining capacity equalization signal to the cell capacity equalizing circuits  20 . The ignition switch can be detected in the OFF state by receipt of a key-OFF signal from the vehicle-side car controller CC. Alternatively, the system can be configured to detect a start signal indicating an inactive state. Further, when cell remaining capacity equalization is performed, the unit switches  16  for all the battery units  10  are turned OFF. As a result, cell remaining capacity equalization can be performed independently within each battery unit  10 , and in particular, when equalization between battery units is performed after cell remaining capacity equalization, high surge current flow into low voltage battery units can be avoided. 
     (Power Source Controller  30 ) 
     As described above, the power source controller  30  issues cell remaining capacity equalization signals to the cell capacity equalizing circuits  20  and unit remaining capacity equalization signals to the unit capacity equalizing circuits  40  according to a specified timing scheme. In addition to recurring time events such as ignition switch key-OFF and key-ON events, equalization operations can also performed at random times when equalization is judged to be necessary. For example, the necessity for equalization between battery cells  11  can be judged for each battery unit  10  based on the cell voltages detected by each cell voltage detection circuit  25 . A cell remaining capacity equalization directive to equalize remaining capacity between battery cells  11  is issued only to the cell capacity equalizing circuits  20  of battery units  10  judged to require equalization. Accordingly, only the battery units  10  that require cell remaining capacity equalization are equalized at times when that equalization becomes necessary. 
     After cell remaining capacity equalization has been completed, the power source controller  30  can conduct unit remaining capacity equalization. In this case as well, the system configuration is not limited to performing unit remaining capacity equalization on all the battery units  10 . For example, the necessity for unit equalization can be judged based on the unit voltage detected by the unit voltage detection circuit  45  for each battery unit. A unit remaining capacity equalization directive is issued only to the unit capacity equalizing circuits of battery units judged to require equalization. Further, the power source controller can also be configured to receive equalization-completed signals to detect completion of cell remaining capacity equalization for applicable battery units. For example, a cell voltage detection circuit or cell capacity equalizing circuit can issue an equalization-completed signal to the power source controller. Or, completion of cell remaining capacity equalization can be judged at the power source controller based on the cell voltages detected by the cell voltage detection circuits. In addition, it is also possible for the power source controller to judge completion of unit remaining capacity equalization based on the unit voltage detected by the unit voltage detection circuit  45  for each battery unit. 
     The power source apparatus can also be provided with a charging and discharging controller (not illustrated) to control battery block  15  charging and discharging, a current detector (not illustrated) to detect charging and discharging current flow in the battery block  15 , a battery capacity computation section (not illustrated) to calculate battery block  15  remaining capacity based on the charging and discharging current detected by the current detector, and a power source-side communication section (not illustrated) to send charging and discharging current limits based on battery block  15  remaining capacity calculated by the battery capacity computation section to the vehicle-side that is being supplied with power. In the example of  FIG. 1 , the power source controller  30  is powered by vehicle electrical system storage (auxiliary) battery. 
     The power output terminals  50  are connected to power input terminals on the vehicle-side to supply power from the battery block  15  to the vehicle-side. Further, as shown in the alternative embodiment car power source apparatus  200  of  FIG. 4 , an output switch  51  can be provided between the power output terminals  50  and the battery block  15 . For this case, at the completion of vehicle operation when the power source controller  30  receives a key-OFF signal from the car controller CC, the power source controller  30  turns the output switch  51  OFF and leaves the unit switches  16  ON for a set time period. Since the series-connected battery units are connected in parallel under these conditions, unit remaining capacity equalization can take place among the battery units. In particular, by performing this operation each time vehicle driving is completed, equalization between battery units can be consistently maintained. 
     The procedure for car power source apparatus cell remaining capacity equalization and unit remaining capacity equalization is described based on the flowchart of  FIG. 5 . First in step S 1 , the start signal from the vehicle-side is judged to determine if it indicates an inactive state. In the example of  FIG. 1 , an inactive state can be judged by the power source controller  30  receiving a key-OFF signal from the car controller CC. For a state that is not inactive, namely for a key-ON state, the power source apparatus procedure is terminated. 
     If the start signal is judged to indicate an inactive state, control proceeds to step S 2  and the power source controller  30  turns all the unit switches  16  OFF. Next, control proceeds to step S 3  and the power source controller  30  judges if equalization between battery cells is necessary for each battery unit based on the cell voltages detected by the cell voltage detection circuits  25 . If equalization is judged unnecessary, control proceeds directly to step S 4 . Otherwise, if cell remaining capacity equalization is judged necessary, control proceeds to step S 3 - 2 . In step S 3 - 2 , the cell capacity equalizing circuit  20  of a battery unit  10  judged to require cell remaining capacity equalization performs equalization between battery cells within the applicable battery unit  10 . Next, control proceeds to step S 4  and the power source controller  30  judges if cell remaining capacity equalization has been completed for all applicable battery units  10 . If cell remaining capacity equalization has not been completed, control returns to repeat step S 3 . When cell remaining capacity equalization is judged to be complete for all the battery units  10 , control proceeds to step S 5 . 
     Next in step S 5 , the power source controller  30  judges if equalization between battery units is necessary based on the battery unit voltages detected by the unit voltage detection circuits  45 . If equalization is judged unnecessary, control proceeds directly to step S 6 . Otherwise, if unit remaining capacity equalization is judged necessary, control proceeds to step S 5 - 2 , in step S 5 - 2 , the unit capacity equalizing circuit  40  for the applicable battery unit  10  performs unit remaining capacity equalization among the battery units  10  and subsequently control proceeds to step S 6 . 
     Finally in step S 6 , the power source controller  30  judges if unit remaining capacity equalization has been completed for all battery units  10 . If unit remaining capacity equalization has not been completed, control returns to repeat step S 5 . When unit remaining capacity equalization is judged to be complete for all the battery units  10 , the power source apparatus procedure is terminated. In this manner, cell remaining capacity equalization and unit remaining capacity equalization are successively executed to eliminate all non-uniformities. 
     The power source apparatus described above can be used as a battery system installed on-board a vehicle. A vehicle with this power source apparatus on-board can be an electric-powered vehicle such as a hybrid car (hybrid vehicle, HV) or plug-in hybrid car that is driven by both an engine and an electric motor, or an electric automobile (electric vehicle, EV) that is driven only by an electric motor. The power source apparatus is used as a power source in these types of vehicles. 
     In  FIG. 6 , an example is shown of the power source apparatus installed on-board a hybrid car that is driven by both an engine and an electric motor. The vehicle HV with an on-board power source apparatus shown in this figure is provided with an engine  96  and a motor  93  that drive the vehicle HV, a battery system  100 B that supplies power to the motor  93 , and a generator  94  that charges the battery system  100 B batteries. The battery system  100 B is connected to the motor  93  and generator  94  via a DC/AC inverter  95 . The vehicle HV is driven by both the motor  93  and the engine  96  while charging and discharging the battery system  100 B batteries. The motor  93  is activated to drive the vehicle during inefficient modes of engine operation such as during acceleration and slow speed driving. The motor  93  is operated by power supplied from the battery system  100 B. The generator  94  is driven by the engine  96  or by regenerative braking during vehicle deceleration to charge the battery system  100 B batteries. 
       FIG. 7  shows and example of an electric vehicle driven only by an electric motor and having a battery system installed on-board. The vehicle EV shown in this figure is provided with a motor  93  that drives the vehicle EV, a battery system  100 C that supplies power to the motor  93 , and a generator  94  that charges the battery system  100 C batteries. The motor  93  is operated by power supplied from the battery system  100 C. The generator  94  is driven by energy from regenerative braking of the vehicle EV to charge the battery system  100 C batteries. 
     The car power source apparatus, car with the power source apparatus installed, and capacity equalizing method for the car power source apparatus of the present invention can be used appropriately as a method of equalizing capacity in vehicles such as a plug-in hybrid electric vehicle that can switch between an electric vehicle (EV) mode and a hybrid electric vehicle (HEV) mode, a hybrid car (hybrid electric vehicle), and an electric automobile (electric vehicle). 
     It should be apparent to those with an ordinary skill in the art that while various preferred embodiments of the invention have been shown and described, it is contemplated that the invention is not limited to the particular embodiments disclosed, which are deemed to be merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention, and which are suitable for all modifications and changes falling within the spirit and scope of the invention as defined in the appended claims. The present application is based on Application No. 2009-222576 filed in Japan on Sep. 28, 2009, the content of which is incorporated herein by reference.