Charging and discharging device

Abstract

A charging and discharging device is disclosed, aiming to charge and supply power simultaneously while reducing power cycling stress. As a charging and discharging ECU installed in an electric vehicle, used to control the charging and supply of power to an external power source, the charging and discharging ECU includes: a receiving unit that receives a charging and supply start time sent from a collector that manages the external power source; a prediction unit that predicts the charging and supply start time sent from the collector; and a setting unit that determines the charging start time and charging end time for timed charging. The setting unit determines the charging end time based on the charging and supply start time predicted by the prediction unit.

Description

Technical Field

[0001] This invention relates to a charging and discharging device. Background Technology

[0002] Patent Document 1 below discloses a vehicle-to-grid (V2G) system capable of bidirectional power transfer between an energy storage device installed in a transmission equipment and a power system. An on-board charging device is known that can supply power or charge based on the start time of a power supply request sent from an aggregator.

[0003] Patent Document 1: Japanese Patent No. 6393834 Summary of the Invention

[0004] In on-board charging devices, the unit experiences two power cycle stresses during the switch from charging to power supply. The repeated heating and cooling of components inside the on-board charging device due to these power cycle stresses is directly related to component stress. Therefore, in on-board charging devices capable of both charging and power supply, it is necessary to reduce the power cycle stresses described above.

[0005] The purpose of this invention is to reduce power cycling stress while charging and supplying power.

[0006] This invention provides a charging and discharging device mounted on an electric vehicle and controlling the charging and discharging of an external power supply device 14. The charging and discharging device includes: a receiving unit that receives a charging start time sent from a collector that manages the external power supply device; a prediction unit that predicts the charging start time sent from the collector; and a setting unit that determines the charging start time and charging end time for timed charging. The setting unit determines the charging end time based on the charging start time predicted by the prediction unit.

[0007] Invention Effects

[0008] According to the present invention, charging and power supply can be performed simultaneously while reducing power cycling stress. Attached Figure Description

[0009] Figure 1 This is a diagram showing the overall structure of the V2G system in this embodiment.

[0010] Figure 2 It indicates composition Figure 1 The diagram shows a portion of the V2G system, including the external power supply unit and the electric vehicle.

[0011] Figure 3 It is used for explanation Figure 2 The flowchart shown illustrates the operation of the charging and discharging ECU.

[0012] Figure 4This is a diagram used to illustrate the effects of this embodiment. Detailed Implementation

[0013] Hereinafter, this embodiment will be described with reference to the accompanying drawings. To facilitate understanding, the same reference numerals will be used as much as possible to refer to the same components in each drawing, and repeated descriptions will be omitted.

[0014] Vehicle-to-Grid (V2G) is a system that facilitates the exchange of electricity between an electric power system, including a commercial power grid, and electric vehicles. When an electric vehicle is not used as a means of transportation, the battery pack installed in the vehicle is used as an energy storage device. Therefore, bidirectional power transfer occurs between the electric vehicles participating in V2G and the power system.

[0015] Figure 1 This is a diagram showing the overall structure of a V2G system. For example... Figure 1 As shown, the V2G system includes: a power system 10, consisting of a power plant 11 that generates electricity using energy such as thermal power, wind power, nuclear power, or solar power, and a power transmission network 12 that includes the power plants 11 as power suppliers; a power demander 13 that needs and receives electricity; an external power supply unit 14 connected to the transmission network 12 via distribution equipment (not shown); an electric vehicle 15, such as an electric vehicle (EV) or a plug-in hybrid electric vehicle (PHEV) with chargeable and dischargeable batteries; a communication network 16; and an aggregator 17 that manages the charging and discharging of the batteries in the electric vehicles 15 via the external power supply unit 14 connected to the communication network 16. The aggregator 17, by managing the charging and discharging of multiple battery storage devices, including the batteries in the electric vehicles 15, can meet the requirements of the power company operating the power plant 11 or the transmission company operating the transmission network 12.

[0016] Figure 2 It indicates composition Figure 1 A block diagram showing an external power supply unit 14 and an electric vehicle 15, which are part of a V2G system. Figure 2 As shown, the external power supply unit 14 includes a connector 22 and a digital communication unit 23 located at the front end of the cable 21. The external power supply unit 14 is sometimes also configured as a charging rack.

[0017] The electric vehicle 15 includes a charging interface 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.

[0018] Next, the components of the external power supply unit 14 will be described. When the connector 22 is connected to the charging interface 101 of the electric vehicle 15, it facilitates the transfer of 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 uses power line communication technology to overlap the power transferred between the external power supply unit 14 and the electric vehicle 15 obtained from the aggregator 17. Therefore, as long as the connector 22 is connected to the charging interface 101 of the electric vehicle 15, control signals from the aggregator 17 are sent to the electric vehicle 15.

[0019] Next, the constituent components of the electric vehicle 15 will be described. The charging interface 101 is detachable from the connector 22 of the external power supply device 14. When the connector 22 of the external power supply device 14 is installed on the charging interface 101, the digital communication unit 102 receives a signal superimposed on the power from the external power supply device 14 via power line communication (digital communication) technology. When the electric vehicle 15 participates in V2G (Vehicle-to-Everything) communication, it performs actions corresponding to the commands indicated by the signal. Furthermore, the connection method between the electric vehicle 15 and the external power supply device 14 is not limited to a physical connection based on the charging interface 101 and the connector 22; it can also be an electromagnetic connection such as non-contact charging and discharging when the charging interface 101 and the connector 22 are in close proximity.

[0020] The bidirectional charger 103 converts the AC voltage obtained from the external power supply unit 14 via the charging interface 101 and the digital communication unit 102 into DC voltage. The main battery 104 is charged using the DC voltage generated by the bidirectional charger 103. Furthermore, the bidirectional charger 103 converts the DC voltage discharged from the main battery 104 into AC voltage. The AC voltage generated by the bidirectional charger 103 is then sent to the external power supply unit 14 via the charging interface 101. The main battery 104 is, for example, a secondary battery that outputs a high DC voltage of 100-200V, and supplies power to an electric motor (not shown), which serves as the drive source for the electric vehicle 15.

[0021] The converter 105 steps down the output voltage of the main battery 104 from DC to a constant voltage. The power stepped down by the converter 105 is used to charge the auxiliary battery 106. The auxiliary battery 106 is, for example, a secondary battery with a low DC output voltage of 12V, which supplies power to auxiliary equipment of the electric vehicle 15.

[0022] Figure 2The charging / discharging ECU 107, battery ECU 108, and wireless unit 109, enclosed by dashed lines, start or stop according to commands indicated by signals received by the digital communication unit 102, even when the electric vehicle 15 is parked. The charging / discharging ECU 107 controls the operation of the bidirectional charger 103. By controlling the operation of the bidirectional charger 103, the charging / discharging ECU 107 charges or discharges the main battery 104. The battery ECU 108 outputs the remaining capacity (State of Charge: SOC) of the main battery 104 and performs control corresponding to the charge storage state of the main battery 104.

[0023] The wireless unit 109 wirelessly transmits information such as whether the electric vehicle 15 participates in V2G, the level of enthusiasm when participating in V2G, the time period during which it can participate in V2G, and the discharge state of the main battery 104 to the aggregator 17. Furthermore, the participation in V2G, the level of enthusiasm when participating in V2G, and the time period during which it can participate in V2G are preset by the owner of the electric vehicle 15. It is also assumed that the owner of the electric vehicle 15 understands that the higher the level of enthusiasm for participating in V2G, the greater the opportunity and amount of discharge of the main battery 104.

[0024] like Figure 2 As shown, the charge / discharge ECU 107 includes a receiving unit 107a, a prediction unit 107b, and a setting unit 107c. The receiving unit 107a receives the charging start time sent from the aggregator 17, which manages the external power supply device 14. The prediction unit 107b predicts the charging start time sent from the aggregator 17. The setting unit 107c determines the charging start time and charging end time for timed charging. The setting unit determines the charging end time based on the charging start time predicted by the prediction unit.

[0025] Next, refer to Figure 3 The processing flow of the charge / discharge ECU 107 will be described below. In step S01, the charge / discharge ECU 107 begins charging according to the instruction from the user. In step S02, following step S01, the prediction unit 107b predicts the V2G charging / power supply start time. The charging / power supply start time is sent from the aggregator 17. The prediction unit 107b can make predictions based on the times of charging / power supply start requests sent from the aggregator 17 in the past. For example, the prediction unit 107b predicts the charging / power supply start time by averaging past time data within a specified range on a weekly basis. The charging / power supply start requests sent from the aggregator 17 are sent when there is an excess or deficiency of power on the system side, so it is inferred that there is a deviation in the time of excess or deficiency of power, and therefore this characteristic can be used for prediction.

[0026] In step S03, following step S02, the setting unit 107c sets a timer for charging. The setting unit 107c sets the timer to end charging at the charging start time predicted by the prediction unit 107b in step S02. By setting the timer to end charging at the charging start time predicted by the prediction unit 107b, V2G charging can begin when the internal components of the charger are at a high temperature. 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 sent by the aggregator 17, charging can begin before the temperature of the internal components of the charger drops, thus helping to alleviate stress. The prediction unit 107b predicts the charging start time by performing machine learning based on the accumulation of deviation data, thus improving prediction accuracy as the amount of data increases.

[0027] In step S04 following step S03, the setting unit 107c determines whether it is the end time of charging. If it is determined to be the end time of charging (step S04: Yes), the process proceeds to step S05. If it is determined not to be the end time of charging (step S04: No), the process repeats step S04.

[0028] In step S05, the charge / discharge ECU 107 stops charging. Following step S05, in step S06, the receiving unit 107a determines whether it has received a charging start indication from the aggregator 17. If it is determined that a charging start indication has been received from the aggregator 17 (step S06: Yes), the process proceeds to step S07. If it is determined that no charging start indication has been received from the aggregator 17 (step S06: No), the process repeats step S06.

[0029] In step S07, the charge / discharge ECU 107 begins V2G charging. In step S08, following step S07, the charge / discharge ECU 107 stops V2G charging. In step S09, following step S08, the charge / discharge ECU 107 stops all operations of the on-board charger. The on-board charger is also called an OBC (On-Board Charger). In this embodiment, the on-board charger includes a charging interface 101, a digital communication unit 102, a bidirectional charger 103, and a charge / discharge ECU.

[0030] exist Figure 4 The image below shows a stress diagram of an on-board charger. (Example:) Figure 4 As shown, the internal components of the vehicle charger are subjected to heating and cooling only once, thus alleviating stress.

[0031] The embodiments described above have been illustrated with reference to specific examples. However, the present invention is not limited to these specific examples. Those skilled in the art can make appropriate design modifications to these specific examples, and as long as they possess the features of the present invention, they are also included within the scope of the present invention. The elements, their configurations, conditions, shapes, etc., of the aforementioned specific examples are not limited to the illustrated elements and can be appropriately modified. As long as no technical contradiction arises, the elements of the aforementioned specific examples can be appropriately combined and changed.

[0032] [Postscript]

[0033] [Postscript 1]

[0034] A charging and discharging device 107 is mounted on an electric vehicle 15 and controls the charging and discharging power supply to an external power supply device 14. The charging and discharging device 107 includes:

[0035] The receiving unit 107a receives the charging start time sent from the aggregator 17 that manages the external power supply device 14;

[0036] Prediction unit 107b predicts the start time of charging / power supply transmitted from aggregator 17; and

[0037] The setting unit 107c determines the charging start time and charging end time of the timer charging.

[0038] The setting unit 107c determines the charging end time based on the charging and power supply start time predicted by the prediction unit 107b, which serves as the charging and discharging ECU 107 of the charging and discharging device.

[0039] According to Note 1, by shortening the switching time from charging to supplying power, the power cycle stress can be reduced by half. The prediction of the power request start time is based on past V2G power supply history, but it can also be predicted using other methods.

[0040] Symbol Explanation

[0041] 14-External power supply unit, 15-Electric vehicle, 17-Aggregator, 107-Charging and discharging ECU (charging and discharging device), 107a-Receiver, 107b-Prediction unit, 107c-Setting unit.

Claims

1. A charging and discharging device mounted on an electric vehicle and controlling the charging and discharging of an external power supply device, characterized in that it comprises: The receiving unit receives the charging start time sent from the aggregator that manages the external power supply device; The prediction unit predicts the start time of the charging / power supply sent from the aggregator; and The setting unit determines the charging start time and charging end time of the timer charging. The setting unit determines the charging end time based on the charging start time predicted by the prediction unit.

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