Capacity Independent Fast Charging of Batteries

• US 20170149256A1
• Filed: 03/28/2016
• Published: 05/25/2017
• Est. Priority Date: 11/24/2015
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Srinivasan, Rengaswamy, Carkhuff, Bliss G., Srinivasan, Lakshminarayan
• Granted Patent: US 9,966,769 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery charging monitor is provided including a non-invasive sensor electrically connected to at least one battery cell of at least one battery, which is configured to measure an internal temperature of the at least one battery cell. The non-invasive internal temperature sensor is connected to the microcontroller that is configured to determine a rate of change of the internal temperature of the at least one battery cell based on the internal temperature of the at least one battery cell, determine a state of charge of the at least one battery cell based on the rate of change of the internal temperature, and cause a charging rate to be applied, by a battery charger, to the at least one battery cell based on the determined state of charge.

Claims

1. A battery charging monitor comprising:

a sensor electrically connected to at least one battery cell of at least one battery, wherein the sensor is configured to measure an internal temperature of the at least one battery cell; and

a microcontroller configured to;

determine a rate of change of the internal temperature of the at least one battery cell based on the internal temperature of the at least one battery cell;

determine a state of charge of the at least one battery cell based on the rate of change of the internal temperature; and

cause a charging rate to be applied, by a battery charger, to the at least one battery cell based on the determined state of charge.

2. The battery charging monitor of claim 1, wherein the determined state of charge comprises a determined state transition.

3. The battery charging monitor of claim 1, wherein the internal temperature of the at least one battery cell comprises at least an anode temperature of the at least one battery cell.

4. The battery charging monitor if claim 1, wherein measuring the internal temperature of the at least one battery cell comprises:

applying a current across the at least one battery cell at a first alternating current (AC) frequency,

measuring a resultant AC voltage across the battery cell

measuring a first phase shift between the applied AC current and the resultant AC voltage across the at least one battery cell, and

determining the temperature of an anode of the at least one battery cell based on the first phase shift.

5. The battery charging monitor of claim 3, wherein measuring the internal temperature of the at least one battery comprises:

applying a voltage across the at least one battery cell at a second (AC) frequency,

measuring a resultant AC current across the battery cell,

measuring a second phase shift between the applied AC voltage and the resultant AC current across the at least one battery cell, and

determining the temperature of a cathode of the at least one battery cell based on the second phase shift.

6. The battery charging monitor of claim 1 further comprising:

a multiplexor,

wherein the at least one battery cell comprises a plurality of battery cells electrically connected to the sensor by the multiplexor, and

wherein the sensor is configured to measure an internal temperature of each battery cell of the plurality of battery cells.

7. The battery charging monitor of claim 1, wherein the electrical connection to the at least one battery cell comprises a connection to each terminal of the at least one battery, and no portion of the sensor is within the at least one battery cell.

8. The battery charging monitor of claim 1, wherein the microcontroller is further configured to:

compare the internal temperature of the at least one battery cell to a temperature threshold; and

cause the charging rate to be reduced in an instance in which the internal temperature exceeds the temperature threshold.

9. The battery charging monitor of claim 1, wherein the sensor is further configured to measure a cell voltage of the at least one battery cell, and

wherein the microcontroller is further configured to:

compare the cell voltage to a voltage threshold, and

cause the charging rate to be reduced in an instance in which the cell voltage exceeds the voltage threshold.

10. The battery charging monitor of claim 1, wherein causing the charging rate to be applied to the at least one battery cell based on the determined state of charge comprises:

applying a first charging rate in an instance in which the state of charge is below a first state of charge threshold, and

applying a second charging rate in an instance in which the state of charge is equal to or above the state of charge threshold.

11. The battery charging monitor of claim 10, wherein the state of charging threshold is about 60 percent.

12. The battery charging monitor of claim 10, wherein the first charging rate is less than or about 0.7 of a capacity of the at least one battery.

13. The battery charging monitor of claim 10, wherein the second charging rate is greater than about 0.7 of a charging capacity of the at least one battery.

14. The battery charging monitor of claim 1, wherein the at least one battery comprises a lithium ion battery.

15. A battery charging monitor comprising:

a sensor electrically connected to at least one battery cell of at least one battery, wherein the sensor is configured to measure an internal temperature of the at least one battery cell; and

a microcontroller configured to;

compare the internal temperature of the at least one battery cell to one or more charging temperature thresholds; and

cause a charging rate to be applied, by a battery charger, to the at least one battery cell based on the comparison of the internal temperature to the one or more charging temperature thresholds.

16. The battery charging monitor of claim 15, wherein the internal temperature of the at least one battery cell comprises at least an anode temperature of the battery.

17. The battery charging monitor of claim 15, wherein causing the charging rate to be applied to the at least one battery cell based on the comparison of the internal temperature to the one or more charging temperature thresholds comprises:

applying a first charging rate in an instance in which the state of charge is below a first charging temperature threshold,

reducing the charging rate, and

applying a second charging rate in an instance in which the first charging temperature threshold has been met.

18. The battery charging monitor of claim 15, wherein the sensor is further configured to measure a cell voltage of the at least one battery cell, and

wherein the microcontroller is further configured to:

compare the cell voltage to a charging voltage threshold, and

apply a constant voltage charging rate in an instance in which the cell voltage satisfies the charging voltage threshold.

19. The battery charging monitor if claim 15, wherein measuring the internal temperature of the at least one battery cell comprises:

applying a current across the at least one battery cell at a first alternating current (AC) frequency,

measuring a resultant AC voltage across the battery cell

measuring a first phase shift between the applied AC current and the resultant AC voltage across the at least one battery cell, and

determining the temperature of an anode of the at least one battery cell based on the first phase shift.

20. The battery charging monitor of claim 19, wherein measuring the internal temperature of the at least one battery comprises:

applying a voltage across the at least one battery cell at a second (AC) frequency,

measuring a resultant AC current across the battery cell,

measuring a second phase shift between the applied AC voltage and the resultant AC current across the at least one battery cell, and

determining the temperature of a cathode of the at least one battery cell based on the second phase shift.