Battery monitor and open circuit protector

• US 6,388,423 B1
• Filed: 02/23/2001
• Issued: 05/14/2002
• Est. Priority Date: 02/23/2001
• Status: Expired due to Fees

• Current Assignee: John W. Schilleci Jr
• Original Assignee: John W. Schilleci Jr
• Inventors: Schilleci, John W. Jr.
• Primary Examiner(s): Toatley, Gregory
• Application Number:
  US09/792,515
• Time in Patent Office: 445 Days
• Field of Search: 320/116, 320/122, 320/120, 320/118
• US Class Current: 320/122
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]

Abstract

A battery open circuit protector for an electrical power distribution system which consists of a number of back-biased diodes in series/parallel arrangement across segments of individual battery cells in a battery. Each diode is back-biased across a segment of individual cells number about 10% to about 15% of the total number of cells making up the battery. Additionally, a voltage divider network analogous to a Wheatstone bridge is connected to the battery and a system distribution control panel wherein the network is connected to the midpoint of the battery cells and includes voltage/current divider resistors to establish monitoring circuits and precision resistors to measure the currents.

Claims

1. A battery bank including a plurality of serially connected battery cells making up a bank of standby batteries coupled in parallel with a battery charger and a DC powered load comprising:

a plurality of back-biased diodes, each of said diodes connected in parallel with a predetermined number of said battery cells forming designated successive segments of said serially connected battery cells, each segment of cells having a diode connected in parallel with the cells of the segment, the predetermined number of diodes being a whole number divisor of the total number of battery cells,

whereby, when at least one of a battery cell in a designated segment becomes an open cell, the diode associated with the segment including the open cell becomes forward biased such that the series connection between the adjacent segments is closed through said diode and the serially connected segments of battery cells remains conductive.

2. The battery bank of claim 1 wherein said predetermined number is between about 5% and about 15% of the total number of individual battery cells.

3. In an electric power distribution system, a battery open circuit monitor for detecting abnormalities in a plurality of serially connected battery cells making up a bank of standby batteries coupled in parallel with a battery charger and a DC powered load and including a circuit for bypassing battery cells experiencing electrical abnormalities in the plurality of serially connected battery cells making up the bank of standby batteries comprising:

a plurality of back-biased diodes, each of said diodes connected in parallel with a predetermined number of said battery cells for forming designated segments of said serially connected battery cells having a diode connected in parallel with the cells of the designated segment;

whereby, when one of a battery cell in a segment becomes an open cell, the diode associated with the segment including the open cell becomes forward biased such that the series connection between the adjacent designated segments is closed through said diode and the plurality of serially connected segments of battery cells remains conductive;

a voltage divider network including a first leg connected to the electrical mid-point of said plurality of serially connected battery cells, said first leg being connected to a galvanometer, and said voltage divider network further including a second leg and a third leg, each of said second and third legs being connected to said galvanometer and respectively, the positive terminal and the negative terminal of said bank of standby batteries;

said second and said third legs each having included therein a resistor to electrically balance said voltage divider network during normal operation of the bank of standby batteries;

whereby said galvanometer provides an indication of electrical imbalance relative to said second leg and said third leg and their associated battery cells when a cell experiences an electrical abnormality.

4. The monitor of claim 3 wherein said selected electrical value is voltage.

5. The monitor of claim 3 wherein said galvanometer is connected to the control system of an electrical power distribution system whereby said galvanometer provides an input of the selected electrical value to the control system.

6. The monitor of claim 4 wherein said galvanometer is connected to the control system through an isolation amplifier.

7. The monitor of claim 3 wherein said galvanometer is connected to the control system by means of a radio frequency transmission.

8. The monitor of claim 3 wherein said first leg said galvanometer is connected in series with a precision resistor and a switch and said voltage divider network includes a fourth leg and a fifth leg, each of said legs each of said fourth and fifth legs are connected to said galvanometer and respectively, the positive terminal and the negative terminal of said bank of standby batteries;

whereby said galvanometer provides an indication of a selected electrical value relative to said fourth leg and said fifth leg and their associated battery cells.

9. In an electric power distribution system having a substation with a station battery, the battery including a plurality of serially connected battery cells making up a battery bank of standby batteries coupled in parallel with a battery charger and a DC powered load comprising:

a plurality of back-biased diodes, each of said back-biased diodes connected in parallel with a selected number of said successive serially connected battery cells, each being back-biased by the voltage across said successive serially connected cells, thereby forming successive designated segments of said serially connected battery cells, each designated segment of cells having a diode connected in parallel with the cells of the designated segment;

whereby, when a battery cell in a designated segment becomes an open cell, the diode associated with the segment including the open cell becomes forward biased such that the series connection between the adjacent segments is closed through said diode and the serially connected segments of battery cells remains conductive.

10. The battery bank of claim 9 wherein each designated segment includes an equal number of cells.

11. The battery bank of claim 9 wherein the number of diodes is a whole number divisor of the total number of serially connected cells.

12. The battery bank of claim 11 wherein the number of diodes is between about 5% and about 15% of the total number of individual battery cells.

13. The battery bank of claim 12 further including a voltage divider network comprising a first leg connected to the electrical mid-point of said plurality of serially connected battery cells, said first leg being connected to a galvanometer, and said voltage divider network further including a second leg and a third leg, each of said second and third legs being connected to said galvanometer and respectively, the positive terminal and the negative terminal of said bank of standby batteries;

said second and said third legs each having included therein a resistor to electrically balance said voltage divider network during normal operation of the bank of standby batteries;

whereby said galvanometer provides an indication of electrical imbalance relative to said second leg and said third leg and their associated battery cells when a cell experiences an electrical abnormality.

14. The battery bank of claim 13 wherein said voltage divider network includes a fourth leg and a fifth leg, each of said legs at one end being connected respectively to the positive terminal of said bank of batteries and the negative terminal of said bank of batteries, and each of said legs at their other end being connected respectively to one of the poles of a double pole, single throw switch, and the throw of said switch being connected through a voltage drop resistor to said galvanometer and said first leg of said voltage divider whereby the voltage of the cells respectively between the midpoint of said band and the positive terminal and the negative terminal of said battery may be measured.

15. The battery bank of claim 13 wherein said galvanometer is connected to the control system of the electrical power distribution system whereby said galvanometer provides an input of the selected electrical value to the control system.

16. The battery bank of claim 15 wherein said galvanometer is connected to the control system through an isolation amplifier.

17. The battery bank of claim 15 wherein said galvanometer is connected to the control system by means of a radio frequency transmission.

18. The battery bank of claim 14 wherein said galvanometer is connected to the control system of the electrical power distribution system whereby said galvanometer provides an input of the selected electrical value to the control system.

19. The battery bank of claim 18 wherein said galvanometer is connected to the control system through an isolation amplifier.

20. The battery bank of claim 18 wherein said galvanometer is connected to the control system by means of a radio frequency transmission.