Power control device and power control method for measuring open-circuit voltage of battery

• US 9,331,512 B2
• Filed: 03/26/2013
• Issued: 05/03/2016
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tsukamoto, Yukari
• Primary Examiner(s): Fantu, Yalkew
• Assistant Examiner(s): HERNANDEZ, MANUEL J
• Application Number:
  US14/395,072
• Publication Number:
  US 20150077063A1
• Time in Patent Office: 1,134 Days
• US Class Current: 1/1
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 53/30 Constructional details of charging stations
• CPC Class Codes: B60L 53/63 in response to network capacity
• CPC Class Codes: B60L 53/64 Optimising energy costs, e.g. responding to electricity rates
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 8/003 Converting light into electric energy, e.g. by using photo-voltaic systems
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02S 50/00 Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 : the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

A power control device includes a relay switch, a controller, a sensor and a battery controller. The relay switch is configured to turn electricity on and off between a battery for supplying a load with electric power and the load. The controller predicts load power characteristics indicating characteristics of power consumed by the load over time, and predicts, based on the predicted load power characteristics, charge/discharge power characteristics indicating characteristics of charge/discharge power of the battery over time. The sensor detects voltage between the terminals of the battery. The controller specify a voltage detection period from the charge/discharge power characteristics that was predicted, over which the charge/discharge power of the battery is equal to or less than a prescribed power over a prescribed period. The battery controller turns off the relay switch and detects the voltage between the battery terminals during the voltage detection period.

Claims

1. A power control device comprising:

a relay switch configured to be connected between a battery for supplying a load with electric power and the load, the relay switch being configured to switch between turning electricity on and off from the battery;

a controller programmed to predict a load power characteristic indicating power consumed by the load over time, and to predict, based on the predicted load power characteristic, a charge/discharge power characteristic indicating power charged/discharged by the battery over time;

a sensor configured to detect voltage between terminals of the battery; and

a battery controller operatively coupled to the relay switch, and programmed to selectively control the relay switch,

the controller being programmed to specify a voltage detection period from the charge/discharge power characteristic that was predicted, over which the power charged/discharged by the battery is equal to or less than a prescribed power over a prescribed period, and

the battery controller being programmed to turn off the relay switch and to detect an open-circuit voltage based on the voltage between terminals of the battery during the voltage detection period.

2. The power control device according to claim 1, further comprising

power-generating means for generating electric power and charging the battery using the generated electric power;

the controller being further programmed to predict a generated-power characteristic indicating the electric power generated by the power-generating means over time, and

the controller being further programmed to predict the charge/discharge power characteristic from the generated-power characteristic and the load power characteristic.

3. The power control device according to claim 2, further comprising

an external power source capable of charging the battery;

the controller being further programmed to cause the battery to charge using the external power source during a period obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source.

4. The power control device according to claim 3, wherein

the external power source is a commercial power source;

and

the controller being further programmed to cause the battery to charge using electric power from a commercial power source during a midnight-power time slot.

5. The power control device according to claim 2, wherein

the controller is further programmed to predict a necessary state of charge for the battery from the load power characteristics;

and

the controller is further programmed to set a target value for charging the battery, in accordance with the necessary state of charge that was predicted.

6. The power control device according to claim 2, wherein

the controller is further programmed to set a charging time period, which is obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source;

and

the controller being further programmed to cause the battery to charge to a fully-charged state during the charging time period.

7. The power control device according to claim 2, wherein

the prescribed period is set to be equal to or greater than a period from when the relay switch is turned off until when the voltage between the terminals of the battery stabilizes.

8. The power control device according to claim 1, further comprising

an external power source capable of charging the battery;

the controller being further programmed to cause the battery to charge using the external power source during a period obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source.

9. The power control device according to claim 8, wherein

the external power source is a commercial power source;

and

the controller being further programmed to cause the battery to charge using electric power from a commercial power source during a midnight-power time slot.

10. The power control device according to claim 9, wherein

the controller is further programmed to predict a necessary state of charge for the battery from the load power characteristics;

and

the controller is further programmed to set a target value for charging the battery, in accordance with the necessary state of charge that was predicted.

11. The power control device according to claim 9, wherein

the controller is further programmed to set a charging time period, which is obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source;

and

the controller being further programmed to cause the battery to charge to a fully-charged state during the charging time period.

12. The power control device according to claim 9, wherein

the prescribed period is set to be equal to or greater than a period from when the relay switch is turned off until when the voltage between the terminals of the battery stabilizes.

13. The power control device according to claim 8, wherein

the controller is further programmed to predict a necessary state of charge for the battery from the load power characteristics;

and

the controller is further programmed to set a target value for charging the battery, in accordance with the necessary state of charge that was predicted.

14. The power control device according to claim 8, wherein

the controller is further programmed to set a charging time period, which is obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source;

and

the controller being further programmed to cause the battery to charge to a fully-charged state during the charging time period.

15. The power control device according to claim 8, wherein

the prescribed period is set to be equal to or greater than a period from when the relay switch is turned off until when the voltage between the terminals of the battery stabilizes.

16. The power control device according to claim 1, wherein

the controller is further programmed to predict a necessary state of charge for the battery from the load power characteristics;

and

the controller is further programmed to set a target value for charging the battery, in accordance with the necessary state of charge that was predicted.

17. The power control device according to claim 1, wherein

the controller is further programmed to set a charging time period, which is obtained by subtracting the voltage detection period from a period set in advance in which it is possible to charge the battery using electric power from the external power source;

and

the controller being further programmed to cause the battery to charge to a fully-charged state during the charging time period.

18. The power control device according to claim 1, wherein

the prescribed period is set to be equal to or greater than a period from when the relay switch is turned off until when the voltage between the terminals of the battery stabilizes.

19. A power control method for controlling electric power comprising:

predicting a load characteristic indicating electric power consumed by a load over time, the load being driven by electric power supplied from a battery;

predicting, based on the predicted load power characteristic, a charge/discharge power characteristic indicating power charged/discharged by the battery over time;

specifying a voltage detection period from the charge/discharge power characteristic that was predicted, over which the power charged/discharged by the battery is equal to or less than a prescribed power over a prescribed period; and

detecting an open-circuit voltage of the battery based on voltage between terminals of the battery during the voltage detection period in which a relay switch, which turns electricity on and off between the battery and the load, is turned off.