Intelligent serial battery charger and charging block

• US 6,822,423 B2
• Filed: 03/10/2003
• Issued: 11/23/2004
• 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, Li, Yiu Cheung, Bai, Long
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/383,613
• Publication Number:
  US 20030160593A1
• Time in Patent Office: 624 Days
• Field of Search: 320/122
• US Class Current: 320/122
• CPC Class Codes: H02J 7/0018 using separate charge circuits

Abstract

A battery charger including a plurality of battery charging sections which are connected in series and a charging current source, said charging section includes at least a first branch and a second branch which are connected in parallel, said first parallel branch includes an electronically controllable bypassing switch, said second parallel branch includes terminals for receiving the positive and negative terminals of a battery and a one-way electronic device which are connected in series, said bypassing switch has a very low impedance when activated or turned-on and a very high impedance when deactivated or turned-off, wherein said one-way electronic device is characterised by a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said bypassing switch is activated, the battery in the charging section in which said bypassing switch is activated is substantially isolated electrically from the charging current, the other charging sections and the other batteries by said one-way electronic device.

Claims

1. A battery charger including a plurality of battery charging sections which are connected in series and a charging current source, each said charging section including at least a first branch and a second branch which are connected in parallel, said first parallel branch including an electronically controllable bypassing switch, said second parallel branch includes terminals for receiving the positive and negative terminals of a battery and a one-way electronic device which are connected in series, said bypassing switch having a very low impedance when activated or turned-on and a very high impedance when deactivated or turned-off, wherein said one-way electronic device is characterized by a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said bypassing switch is activated, and wherein said one-way electronic device allows charging current to flow into said battery but substantially prevents discharge of said battery through said one-way electronic device, said bypassing switches of said plurality of battery charging sections being selectively activatable, said battery charger further comprising control means for selective activation of said bypassing switches and voltage measuring means for measuring terminal voltage of the batteries connected to said battery charging sections, whereby the voltage of a battery in a selected charging section is measured upon selective activation of said bypassing switches.

2. A battery charger according to claim 1, wherein said control and voltage measuring means are adapted so that when the voltage of a battery in a selected battery charging section is to be measured, the bypassing switches of the battery charging sections downstream of said selected battery charging section are activated during measurement of the battery terminal voltage, whereby the negative terminal of the battery in said selected battery charging section is connected to the reference ground of said battery charger.

3. A battery charger according to claim 2, wherein only the positive terminal voltage of the battery in said selected battery charging section is output to said voltage measuring means when the voltage of the battery in said selected battery charging section is being measured.

4. A battery charger according to claim 1, wherein said control and voltage measuring means are adapted so that when the voltage of a battery in a selected battery charging section is to be measured, bypassing switches of the battery charging sections downstream of said selected battery charging section are activated so that the negative terminal of the battery in said selected battery charging section is connected to the reference ground of said battery charger.

5. A battery charger according to claim 4, wherein only the positive terminal voltage of a battery in said selected battery charging section is measured when the voltage of said battery in said selected battery charging section is being measured.

6. A battery charger according to claim 1, wherein only the positive battery terminal voltage is output to said voltage measuring means when measuring the voltage of a battery in a selected battery charging section and only a single voltage output is needed for measuring the voltage of a battery in a selected battery charging section.

7. A battery charger according to claim 6, wherein the measurement of the voltage of a battery in a selected battery charging section comprises a single measurement of a single battery terminal voltage output.

8. A battery charger according to claim 1, wherein the voltage of a battery connected to a selected battery charging section is obtained by measuring the positive terminal voltage of said battery upon activation of the bypassing switches of the battery charging sections downstream of said selected battery charging section, whereby the negative terminal of the battery in said selected battery charging section is connected to the reference ground of said battery charger.

9. A battery charger according to claim 8, wherein the bypassing switch of said selected battery charging section is de-activated when the voltage of a battery in said selected battery charging section is being measured, whereby the batteries in battery charging sections downstream of said selected battery charging section are isolated from the charging current by said one-way electronic device of said selected battery charging section during voltage measurement.

10. A battery charger according to claim 1, wherein said control and voltage measuring means are adapted for high-frequency and repeated open-circuit voltage measurements, so that disruption to battery charging will be minimal.

11. A battery charger according to claim 1, wherein said control and voltage measuring means, said one-way electronic devices and said bypassing switches are adapted for open-circuit voltage measurements of the batteries connected to said battery charging sections.

12. A battery charger according to claim 11, wherein the bypassing switches of the battery charging sections downstream of said selected battery charging section are activated when the voltage of the battery connected to said selected battery charging section is being measured, whereby the batteries in said downstream battery charging sections are isolated from the charging current and other batteries during voltage measurement.

13. A battery charger according to claim 1, wherein said voltage measuring means comprises means for measuring a single voltage output from a charging section.

14. A battery charger according to claim 13, wherein said single voltage output is the positive terminal voltage of the battery in a selected battery charging section the voltage of which is being measured.

15. A battery charger according to claim 13, wherein a single voltage output connection is provided from each battery charging section for battery voltage measurements.

16. A battery charger according to claim 1, wherein the voltage of a battery connected to a selected battery charging section is obtained by measuring the terminal voltage of said battery upon isolation of the batteries immediately downstream of said selected battery charging section.

17. A battery charger according to claim 1, wherein said one-way electronic devices and said bypassing switches are both MOSFETS.

18. A battery charger according to claim 17, wherein the activation states of said bypassing switch and said one-way electronic device of the same battery charging section are opposite.

20. A method of measuring the voltage of a battery connected to a selected battery charging section of a battery charger of claim 1, comprising the steps of isolating said battery from said selected battery charging section, connecting the negative terminal of said battery to the ground of said battery charger by activating the bypassing switches of the battery charging sections downstream of said selected battery charging section so that the negative terminal of said battery in said selected battery charging section is connected to the reference ground of said battery charger, and measuring the battery terminal voltage.

19. A battery charger including a plurality of battery charging sections which are connected in series and a charging current source, each said charging section including at least a first branch and a second branch which are connected in parallel, said first parallel branch including an electronically controllable bypassing switch, said second parallel branch including terminals for receiving the positive and negative terminals of a battery and a one-way electronic device which are connected in series, said bypassing switch having a very low impedance when activated or turned-on and a very high impedance when deactivated or turned-off, wherein said one-way electronic device is characterized by a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said bypassing switch is activated, and wherein said one-way electronic device allows charging current to flow into said battery but substantially prevents discharge of said battery through said one-way electronic device, said one-way electronic device and said bypassing switch of said first and second branches of a charging section being configured so that no current will be discharged from a battery in a charging section either via first branch or said second branch and such that said first and second branches do not form a current loop when a bypassing switch is actuated.