charging and discharging device

Abstract

To reduce power cycle stress while charging and supplying power. [Solution] A charge / discharge ECU 107 mounted on an electric vehicle 15 controls the charging and supplying of power to an external power supply device 14, comprising: a receiving unit 107a that receives the charging and supply start time transmitted from an aggregator that manages the external power supply device 14; a prediction unit 107b that predicts the charging and supply start time transmitted from the aggregator; and a setting unit 107c that determines the charging start time and charging end time for timer charging. The setting unit 107c determines the charging end time based on the charging and supply start time predicted by the prediction unit 107b.

Description

Technical Field

[0001] The present disclosure relates to a charging and discharging device.

Background Art

[0002] Patent Document 1 below discloses V2G (Vehicle to Grid) that enables bidirectional power transfer between a capacitor provided in a transportation device and a power grid. In-vehicle charging devices capable of performing power supply and charging based on the power supply request start time from an aggregator are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an in-vehicle charging device, with the switch from charging to power supply, the power cycle stress of the unit is performed twice. Since the cold and heat of the component temperature inside the in-vehicle charging device are repeated due to the power cycle stress, which directly results in component stress, it is required to reduce the above-mentioned power cycle stress in an in-vehicle charging device capable of charging and power supply.

[0005] An object of the present disclosure is to perform charging and power supply while reducing power cycle stress.

Means for Solving the Problems

[0006] This disclosure relates to a charge / discharge device mounted on an electric vehicle that controls the charging and supplying of power to an external power supply unit 14, comprising: a receiving unit that receives a charging and supply start time transmitted from an aggregator that manages the external power supply unit; a prediction unit that predicts the charging and supply start time transmitted from the aggregator; and a setting unit that determines the charging start time and charging end time for timer charging. The setting unit determines the charging end time based on the charging and supply start time predicted by the prediction unit. [Effects of the Invention]

[0007] According to this disclosure, charging and power supply can be performed while reducing power cycle stress. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the overall configuration of the V2G system in this embodiment. [Figure 2] Figure 2 is a block diagram showing the external power supply unit and electric vehicle that constitute part of the V2G system shown in Figure 1. [Figure 3] Figure 3 is a flowchart illustrating the operation of the charge / discharge ECU shown in Figure 2. [Figure 4] Figure 4 is a diagram illustrating the effects of this embodiment. [Modes for carrying out the invention]

[0009] This embodiment will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0010] V2G (Vehicle to Grid) is a system that facilitates the exchange of electricity between electric vehicles and power grids, including the commercial power grid. When electric vehicles are not used as a means of transportation, the battery storage devices installed in them are utilized as power storage facilities. Therefore, bidirectional power exchange takes place between electric vehicles participating in V2G and the power grid.

[0011] Figure 1 shows the overall configuration of the V2G system. As shown in Figure 1, the V2G system comprises a power grid 10 consisting of a power plant 11 that generates electricity using energy such as thermal, wind, nuclear, or solar power, and a power transmission network 12 for the electricity generated by power suppliers including the power plant 11; power consumers 13 that require electricity and receive power supply; an external power supply unit 14 connected to the power transmission network 12 via distribution equipment (not shown); electric vehicles 15 such as EVs (Electrical Vehicles) and PHEVs (Plug-in Hybrid Electric Vehicles) that have rechargeable and dischargeable batteries; a communication network 16; and an aggregator 17 that manages the charging and discharging of batteries in the electric vehicles 15 via the external power supply unit 14 connected to the communication network 16. The aggregator 17 can meet the demands of power companies operating the power plant 11 or power transmission companies operating the power transmission network 12 by managing the charging and discharging of multiple batteries, including the batteries in the electric vehicles 15.

[0012] Figure 2 is a block diagram showing an external power supply unit 14 and an electric vehicle 15, which constitute part of the V2G system shown in Figure 1. As shown in Figure 2, the external power supply unit 14 includes a connector 22 provided at the end of a cable 21 and a digital communication unit 23. The external power supply unit 14 may also be provided as a charging station.

[0013] The electric vehicle 15 includes an inlet 101, a digital communication unit 102, a bidirectional charger 103, a main battery 104, a converter (CONV) 105, an auxiliary battery 106, a charge / discharge ECU 107, a battery ECU 108, and a wireless unit 109.

[0014] Next, the components of the external power supply unit 14 will be described. The connector 22, when connected to the inlet 101 of the electric vehicle 15, exchanges power between the external power supply unit 14 and the electric vehicle 15. The digital communication unit 23 is connected to the communication network 16 via the home gateway 18 and superimposes the signals obtained from the aggregator 17 onto the electricity exchanged between the external power supply unit 14 and the electric vehicle 15 using power line communication technology. Therefore, the control signals from the aggregator 17 are sent to the electric vehicle 15 when the connector 22 is connected to the inlet 101 of the electric vehicle 15.

[0015] Next, the components of the electric vehicle 15 will be described. The connector 22 of the external power supply unit 14 can be attached to and detached from the inlet 101. When the connector 22 of the external power supply unit 14 is attached to the inlet 101, the digital communication unit 102 receives a signal superimposed on the electricity from the external power supply unit 14 using power line communication (digital communication) technology, and when the electric vehicle 15 participates in V2G, it performs an operation according to the command indicated by this signal. Note that the connection method between the electric vehicle 15 and the external power supply unit 14 is not limited to a physical connection between the inlet 101 and the connector 22, but may also be an electromagnetic connection such as contactless charging and discharging when the inlet 101 and the connector 22 are in close proximity.

[0016] The bidirectional charger 103 converts the AC voltage obtained from the external power supply unit 14 via the inlet 101 and the digital communication unit 102 into a DC voltage. The main battery 104 is charged by the power converted to DC voltage by the bidirectional charger 103. The bidirectional charger 103 also converts the DC voltage discharged from the main battery 104 into an AC voltage. The power converted to AC voltage by the bidirectional charger 103 is sent to the external power supply unit 14 via the inlet 101. The main battery 104 is a secondary battery that outputs a high DC voltage, such as 100-200V, and supplies power to an electric motor (not shown), which is the drive source of the electric vehicle 15.

[0017] Converter 105 steps down the output voltage of main battery 104 to a constant voltage while keeping it DC. The auxiliary battery 106 is charged by the power stepped down by converter 105. The auxiliary battery 106 is a secondary battery that outputs a low DC voltage such as 12V, and supplies power to accessories etc. of the electric vehicle 15.

[0018] The charge / discharge ECU 107, battery ECU 108, and wireless unit 109 enclosed by the dotted line in Fig. 2 are activated or deactivated according to the commands indicated by the signals received by the digital communication unit 102 even when the electric vehicle 15 is parked. The charge / discharge ECU 107 controls the operation of the bi-directional charger 103. By the charge / discharge ECU 107 controlling the operation of the bi-directional charger 103, charging or discharging of the main battery 104 is performed. The battery ECU 108 derives the remaining capacity (SOC: State of Charge) of the main battery 104, and performs control according to the power storage state etc. of the main battery 104.

[0019] The wireless unit 109 wirelessly transmits information such as whether the electric vehicle 15 participates in V2G or not, the degree of enthusiasm when participating in V2G, the time zone when it is possible to participate in V2G, and the discharge state of the main battery 104 to the aggregator 17. Note that whether to participate in V2G or not, the degree of enthusiasm when participating in V2G, and the time zone when it is possible to participate in V2G are preset by the owner of the electric vehicle 15. Also, it is assumed that the owner of the electric vehicle 15 understands that the higher the degree of enthusiasm for participating in V2G, the more opportunities and amount of discharge of the main battery 104.

[0020] As shown in Fig. 2, the charge / discharge ECU 107 includes a receiving unit 107a, a prediction unit 107b, and a setting unit 107c. The receiving unit 107a is a part that receives the charging / discharging start time transmitted from the aggregator 17 that manages the external power supply device 14. The prediction unit 107b is a part that predicts the charging / discharging start time transmitted from the aggregator 17. The setting unit 107c is a part that determines the charging start time and charging end time of timer charging. The setting unit 107c determines the charging end time based on the charging / discharging start time predicted by the prediction unit 107b.

[0021] Next, referring to FIG. 3, the processing flow of the charge / discharge ECU 107 will be described. In step S01, the charge / discharge ECU 107 starts charging based on an instruction from the user. In step S02 following step S01, the prediction unit 107b predicts the V2G charging start time. The charging start time is transmitted from the aggregator 17. The prediction unit 107b can predict from the time of the charging start request transmitted from the aggregator 17 in the past. For example, the prediction unit 107b predicts the charging start time by a method such as averaging the time data within a predetermined past range for each day of the week. Since the charging start request transmitted from the aggregator 17 is transmitted when there is an excess or deficiency in the grid-side power, it is estimated that there is a bias in the time when the excess or deficiency of power occurs, so it can be predicted by utilizing this characteristic.

[0022] In step S03 following step S02, the setting unit 107c sets timer charging. The setting unit 107c sets the timer charging so that charging ends at the charging start time predicted by the prediction unit 107b in step S02. By setting the timer charging so that charging ends at the charging start time predicted by the prediction unit 107b, V2G charging can be started in a state where the temperature of the internal components of the charger is high. For example, even if there is a deviation between the charging start time predicted by the prediction unit 107b and the actual charging start time transmitted by the aggregator 17, charging can be started before the temperature of the internal components of the charger drops, which can contribute to stress relaxation. Since the prediction unit 107b predicts the charging start time while performing machine learning based on the accumulation of the deviated data, the prediction accuracy can be improved as the number of data increases.

[0023] In step S04 following step S03, the setting unit 107c determines whether the charging end time has arrived. If it is determined that the charging end time has arrived (step S04: YES), the process proceeds to step S05. If it is determined that the charging end time has not arrived (step S04: NO), the process repeats step S04.

[0024] In step S05, the charge / discharge ECU 107 stops charging. In step S06, following step S05, the receiver 107a determines whether or not it has received a charge / supply start instruction from the aggregator 17. If it determines that it has received a charge / supply start instruction from the aggregator 17 (step S06: YES), the process proceeds to step S07. If it does not determine that it has received a charge / supply start instruction from the aggregator 17 (step S06: NO), the process repeats step S06.

[0025] In step S07, the charge / discharge ECU 107 starts V2G charging and power supply. In step S08, following step S07, the charge / discharge ECU 107 stops V2G charging and power supply. In step S09, following step S08, the charge / discharge ECU 107 stops all operations of the onboard charger. The onboard charger is also called an OBC (On Board Charger). In this embodiment, the onboard charger includes an inlet 101, a digital communication unit 102, a bidirectional charger 103, and a charge / discharge ECU.

[0026] Figure 4 illustrates the stress image of an on-board charger. As shown in Figure 4, the internal components of the on-board charger are subjected to heating and cooling only once, thus reducing stress.

[0027] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0028] [Note] [Note 1] A charge / discharge device 107 mounted on an electric vehicle 15 that controls the charging and supplying of power to an external power supply device 14, A receiving unit 107a receives the charging and power supply start time transmitted from the aggregator 17 that manages the external power supply unit 14, A prediction unit 107b predicts the charging and power supply start time transmitted from the aggregator 17, It includes a setting unit 107c that determines the start time and end time of charging for timer charging, The setting unit 107c determines the charging completion time based on the charging start time predicted by the prediction unit 107b, and is a charge / discharge ECU 107 as a charge / discharge device.

[0029] According to Appendix 1, power cycle stress can be reduced by half by shortening the timing of the switch from charging to power supply. The power supply request start time is predicted from past V2G power supply history, but it may also be predicted by other means. [Explanation of Symbols]

[0030] 14: External power supply 15: Electric vehicles 17: Aggregator 107: Charge / discharge ECU (charge / discharge device) 107a: Receiver 107b: Prediction section 107c: Setting section

Claims

[Claim 1] A charge / discharge device mounted on an electric vehicle that controls the charging and supplying of power to an external power supply device, A receiving unit that receives the charging and power supply start time transmitted from the aggregator 17 that manages the external power supply device, A prediction unit predicts the charging and power supply start time transmitted from the aggregator 17, It includes a setting unit that determines the start time and end time of charging for timer charging, The setting unit determines the charging completion time based on the charging / discharging start time predicted by the prediction unit, in a charge / discharge device.

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