Low temperature fast charge of battery pack

• US 9,694,699 B2
• Filed: 11/21/2014
• Issued: 07/04/2017
• Est. Priority Date: 03/09/2012
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Inc.
• Inventors: Stewart, Sarah G., Kishiyama, Clay H., Kelty, Kurt R.
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US14/550,619
• Publication Number:
  US 20150077057A1
• Time in Patent Office: 956 Days
• Field of Search: 320107, 320116, 320118, 320119, 320125, 320150, 320160, 320162
• CPC Class Codes: B60L 1/02 to electric heating circuits
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/662 Temperature
• CPC Class Codes: B60L 53/00 Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
• CPC Class Codes: B60L 53/11 DC charging controlled by the charging station, e.g. mode 4
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/27 by heating
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

An automated charge preparation method periodically determines critical parameters for the set of relevant operating conditions, determines whether fast charging is possible, applies fast charging when possible, otherwise applies a dynamically scaled charging rate that is optimized based upon current critical parameters (while optionally heating the individual battery cells as long as fast charging is not available) to reduce/eliminate a risk of lithium-plating.

Claims

1. A method comprising:

(a) determining current parameter values for a set of predetermined operating conditions of a battery pack to be charged;

(b) determining a charge rate for the battery pack to be charged based on the current parameter values, wherein the charge rate is less than a maximum charge rate;

(c) applying the charge rate to the battery pack to be charged; and

dynamically scaling the charge rate based on the current parameter values by periodically looping through steps (a)-(c) until the maximum charge rate is reached and thereafter applying the maximum charge rate to the battery pack to be charged.

2. The method of claim 1, wherein the set of predetermined operating conditions include temperature and state of charge.

3. The method of claim 2, wherein the set of predetermined operating conditions further include cell history.

4. The method of claim 3, wherein cell history includes watt-hour throughput, age and usage.

5. The method of claim 1, wherein the step of determining the charge rate for the battery pack to be charged based on the current parameter values is based on accessing a lookup table using the current parameter values.

6. The method of claim 5, wherein the lookup table relates the current parameter values to the charge rate.

7. The method of claim 1, wherein the battery pack to be charged includes a plurality of battery cells, and further comprising the step of heating the plurality of battery cells.

8. The method of claim 7, wherein the step of heating the plurality of battery cells uses a temperature control system.

9. An apparatus comprising:

a battery pack to be charged;

a battery management system; and

a controller connected to the battery management system;

wherein the battery management system is operable to;

periodically determine current parameter values for a set of predetermined operating conditions of the battery pack to be charged;

and

wherein the controller is operable to;

determine a dynamically scaled charge rate for the battery pack to be charged based on the periodically determined current parameter values, wherein the dynamically scaled charge rate is less than a maximum charge rate; and

apply the dynamically scaled charge rate to the battery pack to be charged until the maximum charge rate is reached and thereafter apply the maximum charge rate to the battery pack to be charged.

10. The apparatus of claim 9, wherein the set of predetermined operating conditions include temperature and state of charge.

11. The apparatus of claim 10, wherein the set of predetermined operating conditions further include cell history.

12. The apparatus of claim 11, wherein cell history includes watt-hour throughput, age and usage.

13. The apparatus of claim 9, wherein the controller is further operable determine the dynamically scaled charge rate for the battery pack to be charged based on the periodically determined current parameter values by accessing a lookup table using the current parameter values.

14. The apparatus of claim 13, wherein the lookup table relates the current parameter values to the dynamically scaled charge rate.

15. The apparatus of claim 9, wherein the battery pack to be charged includes a plurality of battery cells, the apparatus further comprising a temperature control system operable to heat the plurality of battery cells.

16. The apparatus of claim 15, wherein the temperature control system comprises a pack heater and a fluid circulation system coupled to the controller.