Fast charger for high capacity batteries

• US 20030102845A1
• Filed: 11/04/2002
• Published: 06/05/2003
• Est. Priority Date: 11/02/2001
• Status: Active Grant

• Current Assignee: Aker Wade Power Technologies LLC
• Original Assignee: Aker Wade Power Technologies LLC
• Inventors: Wade, James R., Aker, John F.
• Granted Patent: US 6,803,746 B2
• Time in Patent Office: Days
• US Class Current: 320/139
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A highly efficient fast charger for high capacity batteries and methods for fast charging high capacity batteries. The fast charger preferably comprises a rectified AC input of single or preferably three phases, with an optional power factor corrected input, minimally filtered with high frequency, high ripple current capacitors, which is switched with a power switching circuit in the “buck” configuration into an inductor/capacitor output filter. Metallized film capacitors are employed, to minimize the rectified 360 Hertz AC component filtering while providing transient switch protection and ripple current requirements for the buck regulator, to provide a high current fast charger with substantially improved power factor. High power, high frequency switching with minimized output filter size provides a highly filtered DC output. The fast charger is adapted to be constructed in a modular design for simple maintenance.

Claims

1. A fast charger for high capacity batteries, comprising:

an input power conditioner including an AC input rectifier yielding rectified input, and a film capacitor coupled with the AC input rectifier, wherein the film capacitor operates at frequency above about 2 kilohertz;

a power converter including a buck regulator coupled with the input power conditioner to receive rectified input therefrom, and including switching componentry operating at frequency above about 2 kilohertz, producing a power output; and

an inductive filter coupled in power output-receiving relationship to said power converter, to produce a filtered fast charging power output.

2. The fast charger of claim 1, wherein said filtered fast charging power output is at voltage in a range of from about 12 to about 300 volts.

3. The fast charger of claim 1, wherein said filtered fast charging power output has a AC ripple current of less than about 5% of maximum load current when said fast charger is coupled to a high capacity battery.

4. The fast charger of claim 1, wherein said filtered fast charging power output has a AC ripple current of less than about 2.5% of maximum load current when said fast charger is coupled to a high capacity battery.

5. The fast charger of claim 1, wherein said filtered fast charging power output has a voltage AC ripple of less than about 0.5% of maximum load voltage when said fast charger is coupled to a high capacity battery.

6. The fast charger of claim 1, having a charging rate of less than 1.5 hours for at least 80% SOC when said fast charger is coupled to a high capacity battery having 100 Ampere-hours capacity at 30% SOC.

7. The fast charger of claim 1, wherein said switching componentry comprises an insulated gate bipolar transistor (IGBT).

8. The fast charger of claim 1, wherein said switching componentry comprises a trench-gate insulated gate bipolar transistor (IGBT).

9. The fast charger of claim 1, wherein said switching componentry comprises a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

10. The fast charger of claim 1, wherein said switching componentry comprises a flywheel diode.

11. The fast charger of claim 1, wherein said switching componentry comprises a switch operating at a switching frequency in a range of from about 2 kilohertz to about 50 kilohertz and a switching voltage in a range of from about 100 to about 1400 volts.

12. The fast charger of claim 1, wherein said switching componentry comprises a switch operating at a switching frequency in a range of from about 2 kilohertz to about 50 kilohertz and a switching voltage in a range of from about 100 to about 1400 volts, with pulsed current in a range of from about 150 to about 2000 amperes.

13. The fast charger of claim 11, wherein said switching componentry comprises a bipolar transistor.

14. The fast charger of claim 1, wherein said switching componentry comprises an insulated gate bipolar transistor (IGBT) and a flywheel diode.

15. The fast charger of claim 1, wherein said fast charger produces said filtered fast charging power output without substantial capacitive filtering of rectified AC input frequency.

16. The fast charger of claim 1, wherein said power converter comprises PWM circuitry, arranged to modulate operation of said buck regulator.

17. The fast charger of claim 1, wherein said film capacitor comprises an array of capacitors.

18. The fast charger of claim 17, wherein said film capacitor comprises a polymeric film capacitor.

19. The fast charger of claim 18, wherein said polymeric film capacitor comprises a polypropylene film capacitor.

20. The fast charger of claim 1, wherein said film capacitor comprises a high ripple current film capacitor.

21. The fast charger of claim 1, wherein said filtered fast charging power output comprises ripple current not exceeding about 10% of peak current when said fast charger is coupled to a high capacity battery.

22. The fast charger of claim 1, wherein said inductive filter comprises an air core choke inductor.

23. The fast charger of claim 16, wherein said power converter is arranged to synchronously vary a duty cycle of said PWM circuitry in response to AC ripple voltage of said rectified input.

24. The fast charger of claim 23, wherein said power converter is arranged to continuously monitor said ripple voltage and adjust driving of said PWM circuitry on a pulse-by-pulse basis.

25. The fast charger of claim 23, wherein said power converter is arranged to remove 360 Hertz AC ripple component so that said power output comprises constant DC voltage.

26. The fast charger of claim 23, wherein said power converter is arranged to monitor voltage of said power output and to (i) adjust same in relation to a first voltage setpoint, and to further adjust same in relation to current in said power output at a second voltage setpoint.

27. The fast charger of claim 23, wherein said power converter is arranged to monitor voltage and current of said power output and to adjust same in relation to setpoint(s) therefor, while allowing passage of 360 Hertz AC ripple current and voltage to said power output.

28. The fast charger of claim 27, wherein said power converter is arranged to adjust said power output while analog filtering power therein and time averaging same to damp adjustment of said power output.

29. The fast charger of claim 27, wherein said power converter is arranged to adjust said power output while damping adjustment of said power output by at least one of (i) numerical methods technique and (ii) constraining adjustment frequency by a predetermined constraint thereon.

30. The fast charger of claim 1, further comprising a programmable controller programmably arranged to control time-varying charging at a fixed charging variable condition, wherein said charging variable is selected from the group consisting of charging voltage and charging current.

31. The fast charger of claim 30, wherein said programmable controller is programmably arranged to control time-varying charging according to an IVI charging profile.

32. The fast charger of claim 31, wherein said IVI charging profile comprises a first constant current charging to about 50% of battery capacity, a second constant voltage charging until the battery reaches the charge rate of 5A/100 Ahr of capacity, and a third constant current charging to rated battery Ahrs capacity.

33. The fast charger of claim 1, further comprising a programmable controller programmably arranged to control charging current below a predetermined current set point.

34. The fast charger of claim 33, wherein said predetermined current set point is in vicinity of about 30 amperes.

35. The fast charger of claim 33, wherein said charging current is maintained below a predetermined current set point by pulse width switching of said switching componentry.

36. The fast charger of claim 1, further comprising thermal management element(s) for maintaining temperature of a battery during charging by the fast charger.

37. The fast charger of claim 36, wherein said thermal management elements comprise at least one of (i) a fluid flow source for cooling of the battery and (ii) thermally conductive dissipation element(s) for thermally contacting and conductively dissipating heat from said battery.

49. The fast charger of claim 1, constructed and arranged to deliver energy at a voltage in a range of from about 12 to about 300 volts.

50. The fast charger of claim 1, coupled to a high capacity lead-acid battery for delivery of said filtered fast charging power output to said battery.

38. A battery charger comprising a battery charging power transmission member, and a programmable controller programmably arranged to control time-varying charging at a fixed charging variable condition, wherein said charging variable is selected from the group consisting of charging voltage and charging current, and wherein said programmable controller is programmably arranged to control time-varying charging according to an IVI charging profile.

39. A battery charger comprising a battery charging power transmission member, and a housing having disposed therein power management circuitry for producing battery charging power, wherein said battery charging power transmission member comprises a charging cable arranged with a retractor enabling said charging cable to be retracted toward the housing from an extended use position to a retracted non-use position, and to be extensibly drawn away from said housing for battery charging.

96. The battery charger of claim 39, wherein said retractor comprises a tensioning reel.

97. The battery charger of claim 39, wherein said retractor comprises a pulley coupled with a counterweight to effect retraction of said charging cable.

40. A battery charging meter, comprising a selectively illuminatable array of illuminating elements, and circuitry for electrically coupling said array to a battery charger, arranged to actuate a progressively increasing number of said illuminating elements for emission of illumination therefrom in correspondence to a state of charge of a battery when connected to the battery charger and during charging of the battery by the battery charger.

41. The battery charging meter of claim 40, wherein the array of illuminating elements is linear, and its end points are demarcated by indicia of respective low/no-charged state and fully charge state of said battery.

42. The battery charging meter of claim 41, wherein the indicia comprise “

E” and

“

F”

indicia.

43. A battery charger comprising a battery charging power transmission member, and a housing having disposed therein power management circuitry for producing battery charging power, said housing including an openable/closable member for selective access to an interior region of said housing, wherein said openable/closeable member is coupled with a member for producing an open circuit condition in said power management circuitry when said openable/closeable member is opened.

44. A method of fast charging high capacity batteries, comprising:

conditioning input power by AC input rectification thereof yielding rectified input, in a circuit including a film capacitor coupled with an AC input rectifier, wherein the film capacitor operates at frequency above about 2 kilohertz;

converting power from said conditioning step in a circuit including a buck regulator and switching componentry operating at frequency above about 2 kilohertz, to produce a power output; and

inductively filtering the power output, to produce a filtered fast charging power output.

46. The method of claim 44, wherein said IVI charging profile comprises a first constant current charging to about 50% of battery capacity, a second constant voltage charging until the battery reaches a charge rate of 5A/100 Ahr capacity, and a third constant current charging to rated battery Ahrs capacity.

45. A method of charging a battery, comprising transmitting charging energy to said battery according to an IVI charging profile.

47. A method of recharging a high capacity battery having a depleted state of charge, comprising:

charging said battery at a rate of greater than 30 Amperes per 100 Ampere-hours of battery capacity, to bring the state of charge of said battery from 30% to 80% of full charge in less than about 1.5 hours; and

maintaining temperature of said battery below 125°

F. during said charging.

48. The method of claim 47, wherein the step of maintaining temperature of said battery below 125°

F. during said charging, comprises thermistically monitoring temperature of electrolyte in said battery, and varying charge rate during said charging.

51. A fast charger for high capacity batteries, comprising:

(a) an AC input;

(b) means for rectifying AC power from said AC input to produce a rectified output;

(c) means for converting said rectified output to a converted DC output for charging a high capacity battery, said means comprising high frequency, high ripple current capacitors switched with a power switching circuit in a buck configuration into an inductor/capacitor output filter; and

(d) cabling for transmission of the rectified output to the high capacity battery.

52. The fast charger of claim 51, wherein said means (b) and (c) are contained in a unitary housing.

53. The fast charger of claim 52, wherein said housing includes an access door.

54. The fast charger of claim 53, wherein the access door is coupled with a circuit breaker to said AC input so that opening of the door interrupts power availability to the fast charger.

55. The fast charger of claim 51, wherein said means (c) comprise a first electronic switch driven by a pulse width modulation circuit and a second electronic switch providing a current path when the first switch is off in a pulse width modulation cycle of the first switch.

56. The fast charger of claim 55, wherein said first electronic switch comprises at least one high ripple current film capacitor.

57. The fast charger of claim 55, wherein said second electronic switch comprises a flywheel diode.

58. The fast charger of claim 55, wherein said wherein said means (c) provide no substantial capacitive filtering of said rectified output in converting same to said converted DC output.

59. A method of fast charging a high capacity battery, comprising generating output charging power with rectification and pulse width modulation of an AC input, modulating the output charging power in response to the rectified AC input waveform, and synchronously varying the pulse width modulation duty cycle in proportion and response to the AC ripple voltage of the rectified AC input waveform, to provide a substantially constant DC voltage output charging power.

60. A battery charger comprising a battery charging power transmission member, and a programmable controller programmably arranged to control time-varying charging at a fixed charging variable condition, wherein said charging variable is selected from the group consisting of charging voltage and charging current, and wherein said programmable controller is programmably arranged to control time-varying charging according to a predetermined charging profile.

61. A fast charger for a high capacity battery, comprising:

an input section including a transformer for voltage adjustment of inputted AC voltage and a rectifier for producing a rectified bus voltage;

a conditioning section arranged to receive the rectified bus voltage, including a first electronic switch, a pulse width modulation circuit driving said first electronic switch, and a second electronic switch providing a current path with the first electronic switch is off in a pulse width modulation cycle of said pulse width modulation circuit, and at least one film capacitor filtering the first electronic switch and output filter circuitry while minimally filtering the bus voltage, said conditioning section producing a conditioned power output; and

an output filter comprising said output filter circuitry, arranged to receive the conditioned power output and produce a charging power output.

62. The fast charger of claim 61, wherein the first switch comprises a power transistor.

63. The fast charger of claim 62, wherein the power transistor is constructed and arranged for switching voltage in a range of from about 100 V to about 1400 V and switching frequency at frequencies of at least 2 kilohertz.

64. The fast charger of claim 62, wherein the power transistor comprises an IGBT.

65. The fast charger of claim 61, wherein the second switch comprises a flywheel diode.

66. The fast charger of claim 61, wherein said output filter comprises an inductor and a high frequency, high ripple current capacitor.

67. The fast charger of claim 61, wherein the pulse width modulation circuit comprises output transducers monitoring the charging power output, a controller circuit reading the transducers, and a controller regulating output of the pulse width modulation circuit.

68. The fast charger of claim 61, wherein said at least one film capacitor comprises a polypropylene film capacitor.

69. The fast charger of claim 61, further comprising a thermistor sensor for sensing battery temperature, and a charging program stored in the fast charger and operatively arranged to vary charging conditions in response to battery temperature sensed by the thermistor sensor.

70. The fast charger of claim 69, wherein the thermistor sensor is arranged for contacting with electrolyte of a battery during charging thereof.

71. The fast charger of claim 69, wherein the thermistor sensor is arranged for contacting of post structure of a battery during charging thereof.

72. The fast charger of claim 69, wherein the thermistor sensor is arranged for contacting of interconnects coupled with a battery during charging thereof.

73. The fast charger of claim 69, wherein the program is operatively arranged to vary charging voltage.

74. The fast charger of claim 69, wherein the program is operatively arranged to vary charging current.

75. The fast charger of claim 69, wherein the program is operatively arranged to shut down the fast charger if battery temperature exceeds a predetermined value.

76. The fast charger of claim 61, wherein the output filter circuitry comprises a magnetic core inductor constructed to prevent occurrence of saturation.

77. The fast charger of claim 76, wherein said magnetic core inductor comprises an open-ended laminated I-core high frequency choke.

98. The fast charger of claim 61, further comprising a charging program stored in the fast charger and operatively arranged to adjust the pulse width modulation cycle of said pulse width modulation circuit in response to AC ripple voltage of the rectified AC input waveform.

99. The fast charger of claim 61, further comprising a program stored in the fast charger, arranged to control said conditioning section to produce a predetermined charging power output, and to adjust operation of the fast charger for at least one variable operating parameter selected from the group consisting of (1) battery voltage, (2) battery capacity, (3) maximum charging rate, (4) charging algorithm and (5) set point times for finishing and equalizing battery charging.

100. The fast charger of claim 61, further comprising a program stored in the fast charger, and arranged for selective control of charging operation steps of the fast charger, wherein said charging operation steps include (a) battery parameter set-up, (b) finish and equalize battery charge, (c) set time and date, (d) delayed start, (e) battery temperature sensing (yes/no), (f) calibration factor, and (g) exit/reversion to normal charging program.

78. A method of fast charging of a high capacity battery, comprising:

rectifying an input AC voltage to produce a rectified bus voltage;

conditioning the rectified bus voltage, by conditioning circuitry including a first electronic switch, a pulse width modulation circuit driving said first electronic switch, and a second electronic switch providing a current path with the first electronic switch is off in a pulse width modulation cycle of said pulse width modulation circuit, and at least one film capacitor filtering the first electronic switch and output filter circuitry while minimally filtering the bus voltage, to produce a conditioned power output; and

filtering said conditioned power output to produce a charging power output for fast charging of the high capacity battery.

79. The method of claim 78, wherein said input AC voltage is a three-phase power input voltage, and the pulse width modulation cycle is modulated in response to AC ripple voltage of the rectified AC input waveform.

80. The method of claim 79, wherein AC ripple component is substantially removed from the charging power output.

81. The method of claim 78, wherein said fast charging is controlled in accordance with a control technique according to the flow chart of FIG. 11.

82. The method of claim 78, wherein said fast charging is controlled in accordance with a control technique according to the flow chart of FIG. 12.

83. The method of claim 78, wherein said fast charging is controlled in accordance with a control technique according to the flow chart of FIG. 14.

84. The method of claim 78, comprising conducting said fast charging in a staged progression of steps including at least one constant current step and at least one constant voltage step.

85. The method of claim 84, including a first constant current step, a second constant voltage step and a third constant current step.

86. The method of claim 85, wherein the first step comprises charging the battery at constant current to about 50% of its capacity.

87. The method of claim 86, wherein the second step comprises charging the battery at constant voltage until the battery reaches a charge rate of about 5A/100 Ahrs. of battery capacity.

88. The method of claim 87, wherein the third step comprises charging the battery at constant current to its rated Ahr. capacity.

89. The method of claim 87, wherein the battery has a state of charge at the conclusion of the second step that is about 90% SOC.

90. The method of claim 78, further comprising maintaining temperature of the battery during fast charging thereof below 125°

F.

91. The method of claim 90, wherein said maintaining temperature comprises flow of coolant air over the battery.

92. The method of claim 90, wherein said maintaining temperature comprises modulating charging conditions to maintain temperature rise incident to charging below a level that would raise battery temperature above 125°

F.

93. The method of claim 90, wherein said maintaining temperature comprises monitoring temperature of electrolyte in said battery, and responsively modulating charging conditions to maintain battery temperature below 125°

F.

94. The method of claim 78, wherein more than one battery is concurrently charged.

95. The method of claim 78, wherein the battery is selected from the group consisting of flooded lead-acid batteries and sealed batteries.