Power System

Abstract

To provide a power system including multiple assembled batteries connected in parallel capable of accurately calculating the estimated value of SOC, for example, while charging all assembled batteries to full charge.SOLUTION: A power system P charges and discharges an external system. The power system P includes: a battery unit Bu including a battery pack 1 and a converter 2; and a control unit 3 that controls the battery unit Bu. Multiple battery units Bu are connected in parallel. The control unit 3 controls the converter 2 to charge the battery pack 1 until the same is fully charged after a specified time has passed since it was fully charged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power supply system, and more particularly to a power supply system in which a plurality of battery units, each including a battery pack and a converter, are connected in parallel. [Background technology]

[0002] JP 2014-103804 A (Patent Document 1) discloses a technology for equalizing the voltages of multiple battery packs in a battery system in which multiple battery packs are connected in parallel. In addition, JP 2020-60581 A (Patent Document 2) discloses the existence of a battery whose OCV (Open Circuit Voltage)-SOC (State Of Charge) characteristics show a flat region (voltage plateau region) over a wide range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-103804 A [Patent Document 2] JP 2020-60581 A Summary of the Invention [Problem to be solved by the invention]

[0004] For batteries with a voltage plateau region in the OCV-SOC characteristics, it is effective to charge the battery until it is fully charged and correct the estimated SOC value (calculate the SOC). However, in a power supply system in which multiple battery packs (batteries) are connected in parallel to a power conversion device, as in Patent Document 1, it is not possible to fully charge all of the battery packs due to differences in internal resistance among the battery packs, etc.

[0005] An object of the present disclosure is to enable, in a power supply system consisting of multiple battery packs connected in parallel, to charge all of the battery packs to full charge and, for example, to accurately calculate an estimated SOC value. [Means for solving the problem]

[0006] The power supply system disclosed herein is a power supply system that charges and discharges between an external system. The power supply system includes a battery unit including a battery pack and a converter, and a control device that controls the battery unit, and the battery units are connected in parallel. The control device controls the converter to charge the battery pack until it is fully charged after a predetermined period of time has passed since it was fully charged.

[0007] According to this configuration, the battery unit is composed of a battery pack and a converter. A power supply system is configured by connecting a plurality of battery units in parallel. Since the battery unit is composed of a battery pack and a converter, the converter can control charging and discharging of the battery pack, and controlling the converter makes it possible to charge the battery pack until it is fully charged. The control device controls the converter to charge the battery pack (battery unit) until it is fully charged after a predetermined period of time has passed since it was fully charged. As a result, since the battery pack is charged until it is fully charged every predetermined period of time, for example, it is possible to correct the estimated value of SOC (calculate SOC) when it is fully charged, and it is possible to calculate SOC with high accuracy. For example, the SOC calculation unit of the control device may set the SOC value to a fully charged value (for example, 100%) when the battery pack is fully charged.

[0008] The types of the assembled batteries constituting the battery unit do not have to be the same, and may include, for example, a first assembled battery composed of iron phosphate lithium ion batteries and a second assembled battery composed of ternary lithium ion batteries. In this case, the control device controls the converter to fully charge the first assembled battery that has been fully charged for a first predetermined period of time, and to fully charge the second assembled battery that has been fully charged for a second predetermined period of time, and may change the predetermined period of time depending on the type of the assembled batteries. Effect of the Invention

[0009] According to the present disclosure, in a power supply system consisting of multiple battery packs connected in parallel, it becomes possible to charge all of the battery packs until they are fully charged, and it becomes possible, for example, to accurately calculate an estimated SOC value. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an overall configuration of a power supply system according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a diagram illustrating an example of an electric vehicle. [Diagram 3] FIG. 2 is a diagram illustrating an example of the configuration of a control device of a power supply system. [Figure 4] 4 is a flowchart showing an example of a charging control process executed in a control device. [Diagram 5] FIG. 13 is a diagram showing an overall configuration of a power supply system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0012] Fig. 1 is a diagram showing the overall configuration of a power supply system P of this embodiment. The power supply system P includes a power supply subunit Su including three battery packs 1 and a converter 2, and a control device 3. In this embodiment, the power supply subunit Su is a battery pack and a PCU (Power Control Unit) mounted on an electric vehicle that have been converted for use in the power supply system P. An example of the configuration of an electric vehicle equipped with a battery pack and a PCU will be described.

[0013] Fig. 2 is a diagram illustrating an example of an electric vehicle. In Fig. 2, the electric vehicle V is a hybrid vehicle that uses both a rotating electric machine and an engine to drive the vehicle. The electric vehicle V includes a battery pack 1, a PCU 20, an engine 30, motor generators MG1 and MG2 as rotating electric machines, a power split mechanism 40, and drive wheels 50.

[0014] The battery pack 1 includes a battery 10 and a system main relay (SMR) 11. The battery 10 is an assembled battery in which single cells (battery cells) made of secondary batteries such as nickel-metal hydride batteries and lithium-ion batteries are electrically connected in series. The output terminals (positive terminal, negative terminal) of the battery pack 1 are connected to a battery connection terminal 25 of the PCU 20. When the SMR 11 is closed, the battery 10 and the PCU 20 are connected, and when the SMR 11 is opened, the connection between the battery 10 and the PCU 20 is cut off. The battery pack 1 is provided with a monitoring unit 15, which detects the voltage VB of the battery 10, the input / output current IB of the battery 10, the temperature of the battery 10, etc.

[0015] The PCU 20 includes a boost converter 21, an inverter 22, and an inverter 23. The boost converter 21 boosts the battery voltage VB input from the battery pack 1 and outputs it to the inverter 22 and the inverter 23. The inverter 22 converts the DC power boosted by the boost converter 21 into three-phase AC power, and drives the motor generator MG1 to start the engine 30, for example. The inverter 22 also converts AC power generated by the motor generator MG1 using the power transmitted from the engine 30 into DC power and returns it to the boost converter 21. At this time, the boost converter 21 is controlled to operate as a step-down circuit. The inverter 23 converts the DC power output from the boost converter 21 into three-phase AC power and outputs it to the motor generator MG2.

[0016] The power split mechanism 40 is a mechanism that is connected to the engine 30 and the motor generators MG1, MG2 and distributes power therebetween. A planetary gear mechanism can be used as the power split mechanism 40, and for example, the engine 30 is connected to a planetary carrier, the motor generator MG1 is connected to a sun gear, and the motor generator MG2 is connected to a ring gear. The rotor of the motor generator MG2 (and the rotating shaft of the ring gear of the power split mechanism 40) is connected to the drive wheels 50 via a reduction gear, a differential gear, and a drive shaft (not shown).

[0017] The boost converter 21 of the PCU 20 includes a reactor and switching elements Q1a, Q1b, Q2a, and Q2b. The switching elements Q1a to Q2b are, for example, IGBT (Insulated Gate Bipolar Transistor) elements, and include diodes connected in anti-parallel to the IGBT elements.

[0018] Inverter 22 is a three-phase inverter and includes a U-phase arm made up of switching elements Q3 and Q4 connected in series between positive electrode line Pl and negative electrode line Nl, a V-phase arm made up of switching elements Q5 and Q6 connected in series between positive electrode line Pl and negative electrode line Nl, and a W-phase arm made up of switching elements Q7 and Q8 connected in series between positive electrode line Pl and negative electrode line Nl. Similar to switching element Q1a, switching elements Q3 to Q8 are switching elements including diodes connected in anti-parallel to IGBT elements.

[0019] The midpoint of the arm of each phase is connected to the coil of each phase of motor generator MG1 via MG1 connection terminal 26. Motor generator MG1 is a three-phase permanent magnet synchronous motor, and may be, for example, an IPM (Interior Permanent Magnet) synchronous motor.

[0020] The inverter 23 is a three-phase inverter similar to the inverter 22, except that the switching elements of the arms of each phase are arranged in parallel. Switching elements Q9a and Q9b correspond to switching element Q3, and switching elements Q10a and Q10b correspond to switching element Q4, forming a U-phase arm. Switching elements Q11a and Q11b correspond to switching element Q5, and switching elements Q12a and Q12b correspond to switching element Q6, forming a V-phase arm. Switching elements Q13a and Q13b correspond to switching element Q7, and switching elements Q14a and Q14b correspond to switching element Q8, forming a W-phase arm.

[0021] The midpoint of the arm of each phase is connected to the coil of each phase of motor generator MG2 via MG2 connection terminal 27. Motor generator MG2 may also be an IPM synchronous motor.

[0022] The electric vehicle V includes, as control devices, a hybrid ECU (Electronic Control Unit) (HV-ECU) 200, a motor generator ECU (MG-ECU) 210, a battery ECU (BT-ECU) 220, and an engine ECU (EG-ECU) 230. Each ECU includes a CPU (Central Processing Unit), a memory, and a buffer (none of which are shown).

[0023] The monitoring unit 15 includes a voltage detection circuit VB that detects the voltage (battery voltage) VB and the cell voltage (single cell voltage) Vb of the battery 10, a current sensor IB that detects the input / output current IB, etc. The BT-ECU 220 calculates the SOC of the battery 10 based on the voltage VB and the input / output current IB detected by the monitoring unit 15, and transmits the SOC to the HV-ECU 200.

[0024] For driving control of electric vehicle V, HV-ECU 200 calculates target engine rotation speed Ne, target engine torque Te, command torque Tm1 for motor generator MG1, and command torque Tm2 for motor generator MG2.

[0025] The MG-ECU 210 performs PWM (Pulse Width Modulation) control on each switching element of the inverter 22 so that the command torque Tm1 is output from the motor generator MG1. The MG-ECU 210 also performs PWM control on each switching element of the inverter 23 so that the command torque Tm2 is output from the motor generator MG2.

[0026] The EG-ECU 230 controls the engine 30 so that the engine 30 is operated at a target engine speed Ne and a target engine torque Te.

[0027] Referring again to FIG. 1, in the power supply system P, the battery pack 1 and the converter 2 are repurposed battery packs 1 and PCU 20 mounted on an electric vehicle V. The positive terminals of the output terminals of the three battery packs 1 (1-1-1, 1-1-2, 1-1-3) are connected to an MG2 connection terminal 27 to which the midpoints of the phase arms (U-phase arm, V-phase arm, W-phase arm) of an inverter 23 (three-phase inverter) of the PCU 20 are connected, via a coil (inductor) 5. The power line between the positive terminal of the battery pack 1 and the coil 5 is connected to the negative terminal of the output terminal of the battery pack 1, via a capacitor 6. The negative terminal of the battery pack 1 is connected to the negative line Nl of the PCU 20 by a power line Nl1. For convenience, the monitoring unit 15 is partially omitted in FIG. 1.

[0028] 1, switching elements Q4, Q5, and Q7 of inverter 22 of PCU 20 are short-circuited. In MG1 connection terminal 26 to which the midpoints of the arms of each phase of inverter 22 are connected, a terminal to which the U-phase arm is connected is connected to the negative terminal of battery connection terminal 25 by power line Nl2. The negative terminal of battery connection terminal 25 is connected to negative terminal 28b of power supply subunit Su. In MG1 connection terminal 26, a terminal to which the V-phase arm and W-phase arm are connected is connected to positive terminal 28a of power supply subunit Su by power line Pl1.

[0029] In this way, by connecting each phase arm of the inverter 23 of the PCU 20 to the battery pack 1, shorting some of the switching elements of the inverter 22, and connecting the MG1 connection terminal 26 to the positive terminal 28a and negative terminal 28b of the power supply subunit Su, the PCU 20 is converted into a converter 2 that controls the voltage of the battery pack 1 (battery 10) connected to each phase arm of the inverter 23.

[0030] In FIG. 1, the battery pack 1 or the battery 10 included in the battery pack 1 corresponds to an example of the "battery pack" of the present disclosure. A chopper circuit consisting of each phase arm, a coil 5, and a capacitor 6 corresponding to one battery pack 1 (connected to one battery pack 1) corresponds to the "converter" of the present disclosure. In FIG. 1, for convenience, three converters are collectively labeled with the reference symbol 2. A configuration including the battery pack 1 and one converter 2 corresponds to the "battery unit" of the present disclosure. For example, in FIG. 1, the battery pack 1-1-1, the U-phase arm (switching elements Q9a, Q9b, Q10a, Q10b), the coil 5 connected to the midpoint of the U-phase arm, and the capacitor 6 provided in the power line between the positive terminal of the battery pack 1-1-1 and the coil 5 correspond to the "battery unit" of the present disclosure. In the description of the present embodiment, the battery units are denoted by the reference symbol Bu without distinguishing between the battery units.

[0031] The power supply subunit Su is composed of three battery units Bu including a converter 2 that is a repurposed PCU 20. In the power supply subunit Su, the battery units Bu are connected in parallel. The power supply system P includes a plurality of power supply subunits Su, and each power supply subunit Su is connected in parallel to a PCS (Power Conditioning System) 100. In this embodiment, the power supply subunit Su includes n (n is a positive integer) power supply subunits Su, and may include, for example, 20 power supply subunits Su. Three battery units Bu (battery packs 1) are connected in parallel to the power supply subunit Su, and in the power supply system P including the 20 power supply subunits Su, 60 battery units Bu (battery packs 1) are connected in parallel. In FIG. 1, n in the symbol Su-n indicates that it is the n-th power supply subunit Su. n in the symbols 1-n-1, 1-n-2, and 1-n-3 indicates the battery pack 1 included in the n-th power supply subunit Su.

[0032] The positive terminal 28a of each power supply subunit Su is connected via a positive line PL to an input / output terminal of the PCS 100. The negative terminal 28b of each power supply subunit Su is connected via a negative line NL to an input / output terminal of the PCS 100.

[0033] The PCS100 is connected to a power system P, a power grid PG, a photovoltaic power generation device 650, and a load (electrical load) 300. The power system PG is, for example, a commercial power source formed from a power plant or a power transmission network. The PCS100 includes a power conversion device, and supplies power generated by the photovoltaic power generation device 650 to the load 300 and performs reverse power flow. The PCS100 converts AC power of the power system PG to DC power and charges the power system P (battery unit Bu). The PCS100 converts discharge power (output power) of the power system P (battery unit Bu) to AC power and supplies it to the load 300 and performs reverse power flow. The load 300 may be a household load (home appliance) or an electrical load in an office or factory.

[0034] 3 is a diagram showing an example of the configuration of the control device 3 of the power supply system P. The control device 3 utilizes the HV-ECU 200, the MG-ECU 210, and the BT-ECU 220 of the electric vehicle V. The H / HV-ECU 220a, and the HV-ECU(1) 220a-1 to the HV-ECU(3) 220a-3 utilize the HV-ECU 200. The MG-ECU 210a utilizes the MG-ECU 210. The BT-ECU 220a1 to the BT-ECU 220a-3 utilize the BT-ECU 220.

[0035] In FIG. 3, the PCS-ECU 500 is a control device that controls the PCS 100, and outputs a power command RP that is a required value of power output from the power supply system P (battery unit Bu) or a required value of power input to the power supply system P, and a voltage command RV that is a command value of the voltage output from the power supply system P. An interface ECU (I / F-ECU) 600 connects the PCS-ECU 500 and a control device 3 (H / HV-ECU 200a), and performs matching between the communication protocol of the PCS-ECU 500 and the communication protocol of the control device 3. The H / HV-ECU 200a calculates a power command RP for each battery unit Bu from the power command RP, voltage command RV, etc. received from the PCS-ECU 500 via the I / F-ECU 600. The H / HV-ECU 200a also outputs a command for charging control of the battery unit Bu (battery 10).

[0036] The sub-control device 3a1 is a control device that controls the power supply subunit Su, which is composed of the MG-ECU 210a, the HV-ECU(1) 220a-1 to the HV-ECU(3) 220a-3, and the BT-ECU 220a1 to the BT-ECU 220a-3. In Fig. 3, the sub-control device 3a1-1 is a control device that controls the power supply subunit Su-1 in Fig. 1, and a sub-control device 3a1 is provided for each power supply subunit Su. That is, the control device 3a has n sub-control devices 3a1, namely, the sub-control device 3a1-1 to the sub-control device 3a1-n.

[0037] In Fig. 3, the BT-ECU(1) 220a-1 monitors the voltage VB, input / output current IB, temperature, etc. of the battery 10 of the battery pack 1-1-1 of the power supply subunit Su-1, and calculates the SOC of the battery 10 (battery pack). The HV-ECU(1) 200a-1 controls the opening and closing of the SMR 11 of the battery pack 1-1-1 based on the power command RP and the voltage command RV. The HV-ECU 200(1) 200a-1 also detects the degree of deterioration of the battery 10 of the battery pack 1-1-1. The BT-ECU(2) 220a-2 and the HV-ECU(2) 200a-2 perform the same processing as the BT-ECU(1) 220a-1 and the HV-ECU(1) 200a-1 for the battery pack 1-1-2. The BT-ECU(3) 220a-3 and the HV-ECU(3) 200a-3 perform the same processing as the BT-ECU(1) 220a-1 and the HV-ECU(1) 200a-1 for the battery pack 1-1-3. The MG-ECU 210a controls the converter 2 (drives the switching elements of each phase arm of the inverter 23) based on the voltage command RV, the power command RP, etc., or based on a charge control command from the H / HV-ECU 200a.

[0038] Sub-controllers 3a1-2 to 3a1-n also perform the same processing as sub-controller 3a1-1 with respect to power supply subunits Su-2 to Su-n.

[0039] In this embodiment, the battery pack 1 (battery 10) is an assembled battery made of lithium ion batteries, and is made up of multiple types of lithium ion batteries. One type of lithium ion battery is a lithium iron phosphate battery (LFP battery). Hereinafter, the battery pack 1 (battery 10) made up of LFP batteries will also be referred to as a first assembled battery. Other types of lithium ion batteries may include ternary lithium ion batteries, manganese lithium ion batteries, NCA lithium ion batteries, etc., and the battery pack 1 (battery 10) made up of these lithium ion batteries will also be referred to as a second assembled battery.

[0040] 4 is a flowchart showing an example of the charging control process executed by the control device 3. This flowchart is repeatedly processed at predetermined time intervals during the operation of the power supply system P. In step (hereinafter, step is abbreviated as "S") 10, the H / HV-ECU 200a determines whether or not there is a battery unit Bu including a first assembled battery (battery pack 1 made of LPF batteries) for which a first predetermined period α has elapsed since the previous battery was fully charged. Also, it determines whether or not there is a battery unit Bu including a second assembled battery (battery pack 1 made of ternary lithium ion batteries, for example) for which a second predetermined period β has elapsed since the previous battery was fully charged. The first predetermined period α may be, for example, one week, and the second predetermined period β may be, for example, 30 days.

[0041] If there is no battery unit Bu including the first assembled battery for which the first predetermined period α has elapsed since the previous full charge and there is no battery unit Bu including the second assembled battery for which the second predetermined period β has elapsed since the previous full charge, a negative determination is made in S10 and the current routine is terminated. If there is a battery unit Bu including the first assembled battery for which the first predetermined period α has elapsed since the previous full charge, or if there is a battery unit Bu including the second assembled battery for which the second predetermined period β has elapsed since the previous full charge, a positive determination is made in S10 and the routine proceeds to S12.

[0042] In S12, the converter 2 of a battery unit Bu for which the first predetermined period α or the second predetermined period β has elapsed (hereinafter, the battery unit Bu is also referred to as the target battery unit Bu) is controlled to charge the battery pack 1 (battery 10) of the target battery unit Bu. The target battery unit Bu may be charged by power supplied from the power system PG, or may be charged by power supplied from another battery unit Bu.

[0043] Next, in S14, it is determined whether the target battery unit Bu is fully charged. The charging of the target battery unit Bu in S12 is CV (Constant Voltage) charging, at least when it is close to full charge. For example, CCCV (Constant Current, Constant Voltage) charging is performed, charging at a constant current until the battery 10 reaches a predetermined voltage, and when the voltage VB of the battery 10 reaches a specified value, charging at a constant voltage is performed. In S14, when the charging current during CV charging becomes equal to or lower than a set value, it is determined that the battery is fully charged. Note that CV charging is not limited to CCCV charging, and CV charging may be performed from the start of charging, or CPCV (Constant Power, Constant Voltage) charging may be performed.

[0044] When the charging current falls below the set value and it is determined in S14 that all the target battery units Bu are fully charged (positive determination), the process proceeds to S16. If all the target battery units Bu are not fully charged, a negative determination is made in S14, the process returns to S12, and charging is continued until all the target battery units Bu are fully charged.

[0045] In S16, the SOC of the fully charged target battery unit Bu is set to 100% (a value indicating a fully charged state), and the current routine is then terminated. In the battery unit Bu (battery 10) whose SOC has been set to 100%, the control device 3 (BT-ECU(1)-(3) 220a-1-220a-3) then estimates (calculates) the SOC using the current integration method. Note that in addition to the current integration method, the SOC may be calculated (corrected) using the OCV-SOC characteristics.

[0046] According to this embodiment, the power supply system P is composed of a plurality of battery units Bu connected in parallel. Since the battery unit Bu is composed of a battery pack 1 (battery 10) and a converter 2, the charging and discharging of the battery pack 1 (battery 10) can be controlled by the converter 2, and the battery 10 can be charged to full charge by controlling the converter 2. The control device 3 controls the converter 2 to charge the battery unit Bu (battery 10) to full charge after a predetermined period has elapsed since it was fully charged. As a result, the battery unit Bu (battery 10) is charged to full charge at predetermined intervals, and the estimation accuracy (calculation accuracy) of the SOC is improved by setting the SOC value to 100% (full charge value) when the battery is fully charged.

[0047] In this embodiment, the first assembled battery composed of LFP batteries is charged to full charge every time a first predetermined period α has elapsed since the previous full charge, and the second assembled battery composed of ternary lithium ion batteries or the like is charged to full charge every time a second predetermined period β has elapsed since the previous full charge. In an LFP battery having a voltage plateau region in the OCV-SOC characteristic, the SOC estimation accuracy (calculation accuracy) is low, and the SOC quickly deviates from the actual value. In this embodiment, the first predetermined period α is set shorter than the second predetermined period β, so that the frequency of correcting the SOC of the LFP battery can be increased, the SOC can be calculated with high accuracy, and the frequency of charging to full charge can be appropriately set for each battery unit Bu.

[0048] In this embodiment, the converter 2 of the battery unit Bu is a repurposed inverter 23 (three-phase inverter) included in the PCU 20 of the electric vehicle V. In addition, the battery pack 1 of the electric vehicle V is used as the battery pack 1 of the battery unit Bu. This can promote the reuse of batteries and PCUs that are collected when the electric vehicle V is replaced or dismantled. In addition, the control device 3 utilizes the HV-ECU 200, MG-ECU 210, and BT-ECU 220 of the electric vehicle V, and can also promote the reuse of these ECUs.

[0049] In the above embodiment, the frequency of charging to full charge was changed depending on the type of lithium ion battery in the battery pack 1 (battery 10). However, regardless of the type of lithium ion battery, all battery units Bu may be charged to full charge every time the first predetermined period α has elapsed since the previous full charge.

[0050] (Modification) 5 is a diagram showing an overall configuration of a power supply system Pa in a modified example. In the above embodiment, an example has been described in which PCU 20 including boost converter 21, inverter 22, and inverter 23 is diverted to converter 2 of power supply system P. In the above embodiment, in particular, inverter 23 having switching elements provided in parallel is used as the switching element of converter 2 in order to enable the passage of large power. However, some PCUs mounted on electric vehicles are provided with one inverter, and some PCUs are not provided with a boost converter.

[0051] The power supply system Pa in the modified example is a PCU equipped with only one inverter, or a circuit in which the inverter portion is extracted from the PCU and used as the converter 2A of the power supply system Pa.

[0052] In FIG. 5, the converter 2A is a repurposed inverter (three-phase inverter) of a PCU mounted on an electric vehicle. In FIG. 5, SR1 and SR2 of the battery pack 1 are system main relays (SMR). As in the above embodiment, the positive terminals of the output terminals of the three battery packs 1 (1-1-1, 1-1-2, 1-1-3) are connected to the midpoints of the phase arms (U-phase arm 2A1, V-phase arm 2A2, W-phase arm 2A3) of the three-phase inverter of the PCU via coils (inductors) 5. The power line between the positive terminal of the battery pack 1 and the coil 5 is connected to the negative terminal of the output terminal of the battery pack 1 via a capacitor 6. The upper arms of the phase arms (U-phase arm 2A1, V-phase arm 2A2, W-phase arm 2A3) of the three-phase inverter are connected to a positive line PL and are connected to the input / output terminals of the PCS 100. The lower arms of each phase arm (U-phase arm 2A1, V-phase arm 2A2, W-phase arm 2A3) of the three-phase inverter are connected to a negative line NL and are connected to an input / output terminal of the PCS 100. The negative terminal of the battery pack 1 is connected to the negative line NL. Note that the monitoring unit 15 is not shown in the figure. In this way, in the power supply system Pa in the modified example, each phase arm of the three-phase inverter of the PCU is connected to the battery pack 1, and the three-phase inverter is diverted to the converter 2A to configure a power supply subunit Sua having three battery units Bu.

[0053] In the above embodiment and modified example, a power supply system in which a three-phase inverter is converted into a converter has been described. However, the converter constituting the battery unit Bu does not have to be a three-phase inverter, and each battery unit Bu may be provided with an independent chopper circuit (converter).

[0054] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 1 battery pack, 2,2A converter, 3,3a control device, 5 coil (inductor), 6 capacitor, 10 battery, 11 SMR, 15 monitoring unit, 20 PCU, 21 boost converter, 22,23 inverter, 25 battery connection terminal, 26 MG1 connection terminal, 27 MG2 connection terminal, 28a positive terminal, 28b negative terminal, 30 engine, 40 power split mechanism, 50 drive wheel, 100 PCS, 200 HV-ECU, 210 MEG-ECU, 220 BT-ECU 230 EG-ECU, 300 load, 500 PCS-ECU, 600 I / F-ECU, 650 solar power generation device, Bu battery unit, MG1 motor generator, MG2 motor generator, Su,Sua power supply subunit, P,Pa power supply system, PG power system, V electric vehicle.

Claims

1. A power supply system that charges and discharges between an external system, a battery unit including a battery pack and a converter; A control device that controls the battery unit, A plurality of the battery units are connected in parallel, the battery pack includes a first battery pack including iron phosphate lithium ion batteries and a second battery pack including ternary lithium ion batteries; the control device controls the converter to charge the first assembled battery until it is fully charged when a first predetermined period has elapsed since it was fully charged, and to charge the second assembled battery until it is fully charged when a second predetermined period has elapsed since it was fully charged; The first predetermined period is set to be shorter than the second predetermined period, The control device includes an SOC calculation unit that calculates an SOC of the battery pack, The SOC calculation unit sets the value of the SOC to a fully charged value when the battery pack is fully charged.

2. 2. The power supply system according to claim 1, wherein the converter is a converted three-phase inverter, and the assembled battery is connected to each phase arm of the three-phase inverter.

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