BATTERY STRING MONITORING SYSTEM

• US 20170102435A1
• Filed: 10/03/2016
• Published: 04/13/2017
• Est. Priority Date: 10/07/2015
• Status: Active Grant

• Current Assignee: Canara Incorporated (Capitol Power Group LLC)
• Original Assignee: Canara Incorporated (Capitol Power Group LLC)
• Inventors: Hanking, Brian J.
• Granted Patent: US 10,120,034 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Aspects of the present disclosure involve a monitoring system for a plurality of batteries connected in series. In one example, the monitoring system includes a monitoring circuit to be coupled across each of a plurality of distinct contiguous subsets of the batteries as a unit. The monitoring circuit includes at least one test signal generation circuit to generate a test signal and apply the test signal to each subset of the batteries, and at least one response measurement circuit to measure a response of each subset of the batteries to the test signal. The monitoring system also includes a control circuit to identify at least one of the subsets of the batteries as including a failing battery based on the measured response of each subset of the batteries.

Claims

1. A monitoring system, comprising:

a monitoring circuit electrically connected to each of a plurality of distinct contiguous subsets of a plurality of batteries connected in series, the monitoring circuit comprising;

at least one test signal generation circuit which generates a test signal and applies the test signal to each subset of the plurality of batteries; and

at least one response measurement circuit which measures a response of each subset of the plurality of batteries to the test signal; and

a control circuit identifying at least one of the subsets of the plurality of batteries as including a failing battery based on the response of each subset of the plurality of batteries.

2. The monitoring system of claim 1, the monitoring circuit further comprising:

a plurality of monitor nodes, each of the plurality of monitor nodes coupled across a separate one of the subsets of the plurality of batteries, each of the monitor nodes comprising;

one of the at least one test signal generation circuit to generate the test signal and apply the test signal to the subset of the plurality of batteries; and

one of the at least one response measurement circuit to measure the response of the subset of the plurality of batteries to the test signal.

3. The monitoring system of claim 1, further comprising:

a measurement database storing the response of each subset of the plurality of batteries over time, wherein the control circuit identifies at least one failing battery based on the responses stored in the measurement database.

4. The monitoring system of claim 1, wherein:

the response comprises a voltage of the subset of the plurality of batteries; and

the control circuit identifies an impending thermal runaway condition in at least one of the plurality of batteries in response to the voltage of the subset increasing over a first period of time.

5. The monitoring system of claim 4, wherein:

the response comprises a first measured voltage of a first subset of the plurality of batteries; and

the control circuit identifies the impending thermal runaway condition based on the measured voltage decreasing over a second period of time following the first period of time while a second measured voltage of a second subset of the plurality of batteries increases over the second period of time.

6. The monitoring system of claim 1, wherein:

the response comprises a measured voltage and a measured current for the subset of the plurality of batteries; and

the control circuit determines an ohmic value for each subset of the plurality of batteries based on the measured voltage and the measured current for each subset of the plurality of batteries, and identifies each subset of the plurality of batteries having a rising ohmic value as having the failing battery.

7. A method comprising:

receiving, via a processor, a plurality of N voltage signals, wherein each voltage signal in the plurality of N voltage signals represents a respective voltage across a respective battery string subset of a plurality of battery string subsets making up a battery string, the battery string comprising M batteries, where M is greater than N;

performing, via the processor, an analysis on the plurality of N voltage signals; and

identifying, based on the analysis, one of a failing battery in the battery string and a failing battery string subset.

8. The method of claim 7, wherein each of the battery string subsets are distinct from one another.

9. The method of claim 7, wherein N equals four, to yield four voltage signals.

10. The method of claim 9, wherein the analysis identifies the one of the failing battery and the failing battery string subset based on mirroring behavior between the four voltage signals.

11. The method of claim 10, wherein the mirroring occurs between a second subset of the battery string paired to a third subset of the battery string, the second subset being contiguous to the third subset, and further occurs between a first subset of the battery string paired to a fourth subset of the battery string, the first subset being contiguous to the second subset and not the fourth subset, the fourth subset being contiguous to the third subset.

12. The method of claim 7, wherein the analysis comprises generating a test signal and receiving, from each respective battery string subset, a respective response from the each respective battery string subset.

13. The method of claim 12, wherein the analysis further comprises identifying an ohmic measurement of the each respective battery string subset based on the respective response from the each respective battery string subset.

14. The method of claim 7, further comprising:

generating a notification for a user to inspect the one of a failing battery in the battery string and a failing battery string subset.

15. A battery monitoring system, comprising:

a processor;

a test signal generator;

a signal response receiver; and

a plurality of battery connections, wherein;

each battery connection in the plurality of battery connections is connected to a respective subset in a battery string;

the test signal generator generates a test signal and applies the test signal to the each respective subset via the plurality of battery connections;

the signal response receiver receives a response from the each respective subset in response to the test signal, to yield a plurality of responses; and

the processor identifies an error in the battery string based on the plurality of responses.

16. The battery monitoring system of claim 15, wherein the plurality of battery connections comprises at least four.

17. The battery monitoring system of claim 15, wherein at least one subset in the battery string having a battery connection has at least two batteries connected in series.

18. The battery monitoring system of claim 15, wherein the processor identifies the error based on mirroring in the plurality of responses.

19. The battery monitoring system of claim 15, wherein the plurality of responses comprise voltage responses and current responses.

20. The battery monitoring system of claim 15, wherein the processor generates an error report for a user describing the error.