Inductively powered battery charger

• US 6,100,663 A
• Filed: 11/03/1998
• Issued: 08/08/2000
• Est. Priority Date: 05/03/1996
• Status: Expired due to Fees

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Boys, John Talbot, Green, Andrew William
• Primary Examiner(s): Riley, Shawn
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/180,189
• Time in Patent Office: 644 Days
• Field of Search: 320/119, 320/108, 320/116
• US Class Current: 320/108
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• 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 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/38 specially adapted for charging by inductive energy transfer
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• 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

Abstract

Loosely coupled inductive power for charging batteries is rectified from a first power pickup winding and the resulting current source is connected to a battery unit. Each current source is controlled by shorting a second resonant winding. Battery banks may be charged using multiple isolated position-tolerant pickups independently controlled according to the condition of the connected battery unit and by overall commands communicated over an isolated link. The battery unit may be a single cell. In a self-stabilizing bank or monoblock a primary inductive conductor is energized using all the cells, individual cells are separately monitored by control means and any below-average cell can be individually charged from the inductive conductor, thus correcting between-cell variations. The charge in all cells within a bank can be held within 30% to 70% of full charge and prevented from drifting towards full or empty during repetitive charge and discharge times.

Claims

1. A battery charger for a rechargeable battery having one or more cells, the charger inductively transferring power from at least one inductive conductor energized at a high frequency, the charger comprising:

a resonant inductive pickup unit providing to the battery a charging current that is inductively transferred from the at least one inductive conductor to whom said pickup unit is coupled, said pickup unit comprising a first control inductor and a second power-handling inductor, a resonating capacitor, and a rectifier;

said first and second inductors being inductively coupled with each other so that when said first inductor is short circuited said second inductor is substantially decoupled from the at least one inductive conductor;

said pickup unit further comprising a shorting switch varying the coupling between the at least one inductive conductor and said pickup unit by shorting said first inductor to control an amount of energy circulating in said pickup unit and an amount of current passed to the battery.

2. The charger of claim 1, wherein said pickup unit further comprises plural pickup windings and control means for controlling said shorting switch to vary the coupling between the at least one inductive conductor and one of said plural pickup windings.

3. The charger of claim 2, wherein said control means determines a charge of the battery and controls said shorting switch responsive to this determination.

4. The charger of claim 2 for charging a bank of a plurality of the batteries, wherein said control means determines a charge of each of the batteries and equalizes these charges.

5. The charger of claim 2 for separately charging each cell of the battery, wherein said control means determines a charge of each of the cells and equalizes these charges.

6. The charger of claim 5 physically located within the battery.

7. The charger of claim 2, wherein said control means controls the battery charge so that the battery is charged at 30% to 70% of full charge.

8. The charger of claim 2, wherein said control means detects a failure in the battery.

9. The charger of claim 2, wherein said control means records battery performance.

10. A vehicle powered by an electric motor, comprising the charger of claim 1 that provides the charging current to the rechargeable battery that powers the electric motor.

11. An electric power storage module that collects energy from an energy source, comprising the charger of claim 1 that provides the charging current to the rechargeable battery that stores the collected energy.