Charge equalizer or series of connected battery strings

• US 6,008,623 A
• Filed: 03/16/1999
• Issued: 12/28/1999
• Est. Priority Date: 11/30/1998
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chen, Tshaw-Chuang, Guey, Zen-Jey
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/270,651
• Time in Patent Office: 287 Days
• Field of Search: 320/116, 320/118, 320/119, 320/121, 320/127, 320/128, 320/139, 320/140, 320/141
• US Class Current: 320/118
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A charge equalizer adapted a battery charger to equally charge series of connected battery strings, comprising battery voltage sensing circuits, a microcontroller, logic and driving circuits, and flyback converters, operates to prevent the batteries of the series of connected battery strings from overcharging by activating the flyback converters to draw out the overcharging currents of the batteries in the series of connected battery strings and charging the whole battery strings by recharging currents which proportion to said drawn out currents as detecting each of the battery voltages in the battery strings being higher than a pre-determined voltage value during charging and digitizing the detected battery voltage signals; so as to achieve the purposes of equal charge in each battery and hence to improve the life of the battery strings as a whole.

Claims

1. A charge equalizer adapting a battery charger to an equally charged series of connected battery strings, comprising:

a battery voltage sensing means for detecting each of the battery voltage in the series of connected battery strings and scaling the detected battery voltages to a proper voltage level to output;

a microcontroller for receiving the output voltage signals scaled to a proper voltage level from the battery voltage sensing means and digitizing the output voltage signals and comparing them with a pre-determined voltage value, if any one of the digitized voltage signals from the batteries of the series of connected battery is higher than the pre-determined voltage value, to output a corresponding digital signal; and

for producing a set of pulse-width-modulated (PWM) signals to output;

a logic and driving means for receiving the digital signals and the pulse-width-modulated signals from the microcontroller and enhancing the driving capability of these signals after a logic process, then to output; and

a flyback converter means for receiving the signals from the logic and driving means then to draw out the currents of the batteries in the series of connected battery strings as the digitized voltage signals are higher than the pre-determined voltage value, and then to charge the whole battery strings by recharging currents which proportion to said drawn out currents.

2. A charge equalizer of claim 1, wherein said flyback converter means comprises multiples of flyback converters.

3. A charge equalizer of claim 2, wherein said battery voltage sensing means comprises multiples of battery voltage sensing circuits.

4. A charge equalizer of claim 3, wherein said multiples of flyback converters and said multiples of battery voltage sensing circuits utilize said microcontroller in common.

5. A charge equalizer of claim 2, wherein said a set of pulse-width-modulated (PWM) signals produced by said microcontroller can control the operation of said multiples of flyback converters simultaneously.

6. A charge equalizer of claim 2, wherein said microcontroller controls said flyback converters to draw out the currents of corresponding said batteries in the series of connected battery strings as the voltages of said batteries being higher than the pre-determined voltage respectively by programmable changing the duty cycles of pulse-width-modulated signals, so that it controllably draws out the currents from the batteries as well as controlling to charge the whole battery strings by recharging currents which proportion to said drawn out currents.