Intelligent serial battery charger and charging block

• US RE41,676 E1
• Filed: 07/02/2004
• Issued: 09/14/2010
• Est. Priority Date: 09/03/2001
• Status: Expired due to Fees

• Current Assignee: GPE International Limited (Gold Peak Industries Limited)
• Original Assignee: GPE International Limited (Gold Peak Industries Limited)
• Inventors: Yau, Kwok Wong, Bai, Long, Li, Yiu Cheung
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Berhanu; Samuel
• Application Number:
  US10/883,193
• Time in Patent Office: 2,265 Days
• Field of Search: 320119-122
• US Class Current: 320/122
• CPC Class Codes: H02J 7/0022 Management of charging with batteries permanently connected to charge circuit H02J7/0014 takes precedence

Abstract

A serial battery charger including a number of serially connected battery charging sections in which the battery charging section is characterized by a first and second parallelly connected branches. The first branch includes terminals for connecting to the battery to be charged and a current blocking device and the second branch includes a by-passing switch which shunts across the terminals of the first branch when activated. The blocking device in the first branch prevents adverse reverse current flow from the battery to the charger when there is no power supply and also functions as a current block to prevent adverse flow of current from the battery into the shunting by-passing switch when the power supply to the charging section is in operation. This invention provides a simple solution to fulfil the conflicting requirements of an intelligent serial battery charger.

Claims

1. A serial battery charger including a charging section which includes at least first and second parallelly connected branches, said first parallel branch includes an electronically controllable by-passing switch and said second parallel branch includes positive and negative terminals for receiving respectfully the positive and negative terminals of a battery and an one-way electronic device connected in series, said by-passing switch has a very low impedance when turned-on and a very high impedance when turned-off, said one-way electronic device is characterised in that it has a very low-impedance when current flows from said charging section into said battery terminals and it has a high-impedance when said by-passing switch is turned on.

2. A battery charger according to claim 1, further including a micro-controller to monitor at least one parameter of the battery being charged and activate said by-passing switch by forming a low-impedance shunting across said first parallel branch when one or more of said measured battery parameters satisfies a pre-determined condition.

3. A battery charger according to claim 2, wherein said battery parameter include any one or more of the following parameters:

-open-circuit voltage, close-circuit voltage and the temperature of said battery.

5. A battery charger according to claim 1 15, wherein said one-way electronic device is a diode.

6. A battery charger according to claim 1 15, wherein said by-passing switch is a field-effect-transistor (“

FET”

), including a MOSFET.

7. A battery charger according to claim 6, wherein said gate terminal of said FET is connected to said micro-controller for activating and de-activating said by-passing switch.

8. A charging block for use in a serial battery charger including at least first and second parallelly connected branches, said first parallel branch includes an electronically controllable by-passing switch and said second parallel branch includes positive and negative terminals for receiving respectfully the positive and negative terminals of a battery and an one-way electronic device connected in series, said by-passing switch has a very low impedance when turned-on and a very high impedance when turned-off, said one-way electronic device is characterised in that it has a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said by-passing switch is turned on.

9. A charging block according to claim 8, further including a micro-controller to monitor at least one parameter of the battery being charged and activate said by-passing switch by forming a low-impedance shunting across said first parallel branch when one or more said measured battery parameters satisfies a pre-determined condition.

10. A serial battery charger including a battery charging section which includes at least first and second parallely connected branches, wherein said first branch includes a diode serially connected with the terminals for connecting the battery to be charged and said second branch includes a MOSFET by-passing switch, said by-passing switch is connected across said first branch and provides low-impedance shunting when activated, said blocking diode has a low-impedance when current flows into said battery to be charged and has a high-impedance when there is no power supply from said battery charger or when said by-passing switch is turned on.

11. A battery charger according the claim 10, wherein the gate of said by-passing MOSFET is connected to a micro-controller which controls the gate voltage of said MOSFET to turn on or turn off said MOSFET such that when said MOSFET is turned on, the impedance across the drain-source terminals of said MOSFET is low, thereby activating the by-passing function, and, when said MOSFET is turned off, the impedance across the drain-source terminals is very high, thereby de-activating the by-passing function.

12. A battery charger including a plurality of battery charging sections which are connected in series, wherein each said charging section includes at least first and second parallelly connected branches, said first parallel branch includes an electronically controllable by-passing switch and said second parallel branch includes positive and negative terminals for receiving respectfully the positive and negative terminals of a battery and an one-way electronic device connected in series, said by-passing switch has a very low impedance when turned-on and a very high impedance when turned-off, said one-way electronic device is characterised in that it has a very low-impedance when current flows from said charging section into said battery terminals and it has a high-impedance when said by-passing switch is turned on.

13. A battery charger according to claim 12, further including a micro-controller to monitor at least one parameter of the battery being charged and activate said by-passing switch by forming a low-impedance shunting across said first parallel branch when one or more of said measured battery parameters satisfies a pre-determined condition.

14. A battery charger according to claim 12, wherein said one-way electronic device is a diode.

15. A serial battery charger for charging a plurality of discrete batteries, the battery charger comprising:

a charging current source,

a plurality of battery charging sections connected in series for charging a corresponding plurality of discrete batteries, and

a micro-controller;

wherein each one of said battery charging sections comprises first and second branches which are connected in parallel,

said first parallel branch including an electronically controllable bypassing switch, and

said second parallel branch comprising a positive terminal and a negative terminal for receiving respectively the positive and negative terminals of a battery and a one-way electronic device connected in series;

wherein each said bypassing switch has a very low impedance when turned-on and a very high impedance when turned-off,

wherein each said one-way electronic device has a very low impedance to a battery charging current which flows from said current source into the positive battery terminal, and said one-way electronic device has a very high impedance when said bypassing switch is turned on, and

wherein said micro-controller is configured so that the bypassing switch of a battery charging section is activated to form a low-impedance shunt across that battery charging section upon physical removal of a battery from that battery charging section to permit charging of other batteries in other battery charging sections of said battery charger to continue.

4. A battery charger according to claim 3 15, wherein said battery parameters further include the detection of the type and presence of a battery.

16. A serial battery charger according to claim 15, wherein the bypassing switches of said plurality of charging sections are repeatedly activated during a battery charging process for assessing charging parameters of a battery.

17. A serial battery charger according to claim 16, wherein said bypassing switches are repeatedly activated by said micro-controller at a high frequency.

18. A serial battery charger according to claim 16, wherein said micro-controller and said bypassing switches of said plurality of battery charging sections are adapted so that said bypassing switches are repeatedly and individually actuatable during battery charging to enable the charging conditions of batteries connected to said plurality of battery charging sections to be assessed.

19. A serial battery charger according to claim 15, wherein said micro-controller and said bypassing switches of said plurality of battery charging sections are configured so that said bypassing switches are repeatedly actuated during battery charging, to assess charging conditions of batteries connected to said plurality of battery charging sections.

20. A serial battery charger according to claim 19, wherein said bypassing switches of said plurality of battery charging sections are selectively actuatable during a battery charging process, for individually monitoring the charging conditions of batteries connected to said plurality of battery charging sections.

21. A serial battery charger according to claim 19, wherein said micro-controller and said bypassing switches are adapted so that the bypassing switch of a battery charging section is activated when one parameter of a battery connected to said battery charging section satisfies a pre-determined condition.

22. A serial battery charger according to claim 19, wherein, upon actuation of a bypassing switch of a selected battery charging section, said one-way electronic device of said selected battery charging section becomes current blocking, whereby a battery connected to said selected battery charging section is effectively isolated from both said first and second parallel branches.

23. A serial battery charger according to claim 19, wherein said micro-controller and said bypassing switches are adapted so that, when a battery is removed from a battery charging section, or when the terminal voltage of a battery is to be measured, the bypassing switch of said battery charging section is actuated.

24. A serial battery charger according to claim 19, wherein the bypassing switch of a selected battery charging section is actuated upon detection of a battery terminal voltage exceeding the supply voltage of said selected battery charging section.

25. A serial battery charger according to claim 19, wherein said one-way electronic device is disposed against discharge of a battery through said second parallel branch.

26. A battery charger according to claim 15, wherein the current rating of said charging current source is at a rate of 1C or above, and wherein said micro-controller and said bypassing switches of said plurality of charging sections are arranged for high-frequency switching and are selectively activatable.

27. A battery charger according to claim 26, wherein said bypassing switch, comprises a MOSFET, and said one-way electronic device comprises a blocking diode, said blocking diode having a low-impedance when current flows into the battery being charged and a high-impedance when there is no power supply from said battery charger.

28. A battery charger according to claim 15, wherein said bypassing switches of said plurality of battery charging sections are individually activatable and deactivatable, and wherein a battery connected to a battery charging section with the bypassing switch activated is effectively isolated from the circuitry of said charging section.

29. A battery charger according to claim 28, wherein said one-way electronic device is a blocking diode and said bypassing switching is controlled by said micro-controller.

30. A battery charger according to claim 28, further comprising voltage measuring means, wherein said micro-controller, said voltage measuring means, said one-way electronic devices and said bypassing switches are adapted for high-frequency and repeated voltage measurements of batteries connected to said battery charging sections.

31. A battery charger according to claim 30, wherein the voltage of a battery connected to a selected battery charging section is measured upon isolation of said battery from said selected battery charging section by activation of the bypassing switch of said selected battery charging section.

32. A serial battery charger according to claim 16, wherein said charging current source is adapted for charging batteries at a charging current rate of 1C and above, said bypassing switches are individually controllable by said micro-controller, and said bypassing switches are adapted for high-frequency switching so that the charging conditions of a battery can be monitored during the entire battery charging process.

33. A battery charger according to claim 15, wherein said micro-controller is also configured for monitoring at least one parameter of a battery being charged in a battery charging section and for activating the bypassing switch of a battery charging section by forming a low-impedance shunting across the first parallel branch of that battery charging section when one of said parameters of the battery connected to that battery charging section satisfies a pre-determined condition, said battery parameters including open-circuit voltage, close-circuit voltage and the temperature of said battery.

34. A battery charger according to claim 15, wherein each charging section is for charging an AA or an AAA battery.

35. A battery charger according to claim 15, wherein said bypassing switch is activated to form a low-impedance shunt across one of the battery charging sections upon detection of overheating of a battery from that battery charging section of the battery charger so that charging of batteries in other battery charging sections of said battery charger continues.

36. A battery charger according to claim 15, wherein said bypassing switch activated to form a low-impedance shunt across one of the battery charging sections upon detection of a defective battery in that battery charging section of the battery charger so that charging of batteries in other battery charging sections of said battery charger continues.

37. A battery charger according to claim 15, wherein said bypassing switch is activated to form a low-impedance shunt across one of the battery charging sections upon detection of a fully charged battery in that battery charging section of the battery charger so that charging of batteries in other battery charging sections of said battery charger continues.

38. A battery charger according to claim 15, wherein said bypassing switch is repeatedly activated to form a low-impedance shunt across one of the battery charging sections for battery voltage measurements during a battery charging process.

39. A battery charger according to claim 15, wherein said battery charger comprises a constant current source.

40. A battery charger according to claim 15, wherein said micro-controller is further configured so that the bypassing switch of a battery charging section is activated to form a low-impedance shunt across that battery charging section when a defective or an overheated battery is present in that battery charging section to permit charging of other batteries in other battery charging sections of said battery charger to continue.

41. A battery charger according to claim 15, wherein said micro-controller is further configured so that the bypassing switch of a battery battery charging section is operated to permit charging of said battery when said battery is inserted into that battery charging section.