Forming an Electrode

Patent metadata

Field	Value
Publication number	US-2018131045-A1
Application number	US-201815862792-A
Country	US
Kind code	A1
Filing date	Jan 5, 2018
Priority date	Jul 6, 2015
Publication date	May 10, 2018
Grant date	—

Abstract

A method is provided for forming a negative electrode for a lithium-ion cell. The method include the steps of: carrying out first constant-current charging with a first charging current until a first half-cell potential with regard to a reference electrode is reached; carrying out first constant-voltage charging at the first half-cell potential with regard to the reference electrode until a second charging current is reached; carrying out AC voltage excitation or alternating current excitation over a frequency time period; carrying out second constant-current charging with a third charging current until a second half-cell potential with regard to the reference electrode is reached; and carrying out second constant-voltage charging at the second half-cell potential with regard to the reference electrode until a final charging current is reached or until a maximum constant-voltage charging duration is reached.

First claim

What is claimed is:

1 . A method for forming a negative electrode for a lithium-ion cell, comprising the steps of:
first constant-current charging with a first charging current until a first half-cell potential with regard to a reference electrode is reached; first constant-voltage charging at the first half-cell potential with regard to the reference electrode until a second charging current is reached; AC voltage excitation or alternating current excitation over a frequency time period; second constant-current charging with a third charging current until a second half-cell potential with regard to the reference electrode is reached; and second constant-voltage charging at the second half-cell potential with regard to the reference electrode until a final charging current is reached, or until a maximum constant-voltage charging duration is reached.

2 . The method as claimed in claim 1 , wherein
a resting voltage phase, over a relaxation time interval, is executed after the first constant-voltage charging and prior to AC voltage excitation or alternating current excitation.

3 . The method as claimed in claim 1 , wherein
the first charging current lies within a range of one hundredth to two times the one-hour current.

4 . The method as claimed in claim 1 , wherein
the first half-cell potential lies within a range of 500 mV to 1,200 mV, with respect to a Li/Li+ reference electrode.

5 . The method according to claim 1 , wherein
the second charging current is smaller than the first charging current.

6 . The method as claimed in claim 2 , wherein
the relaxation time interval is at least one minute.

7 . The method as claimed in claim 1 , wherein
the AC voltage excitation or alternating current excitation proceeds at a constant frequency.

8 . The method as claimed in claim 7 , wherein
the constant frequency lies within a range of 0.001 kHz to 1,000 kHz.

9 . The method as claimed in claim 1 , wherein
the AC voltage excitation or alternating current excitation involves sequential excitation at at least two frequencies, or excitation in the form of a frequency sweep.

10 . The method as claimed in claim 9 , wherein
each frequency of the at least two frequencies or the frequency sweep lies within a range of 0.001 kHz to 1,000 kHz.

11 . The method as claimed in claim 7 , wherein
the frequency time period lies within the range of 0.01 seconds to 120 minutes.

12 . The method as claimed in claim 9 , wherein
the frequency time period lies within the range of 0.01 seconds to 120 minutes.

13 . The method as claimed in claim 1 , wherein
the third charging current lies within a range of one hundredth to two times the one-hour current.

14 . The method as claimed in claim 1 , wherein
the second half-cell potential lies within a range of 5 mV to 300 mV with regard to the Li/Li+ reference electrode.

15 . The method as claimed in claim 1 , wherein
the final charging current is smaller than the third charging current.

16 . The method as claimed in claim 1 , wherein
the maximum constant voltage charging time is at least one minute.

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Antonopoulos Byron Konstantinos

Classifications

• H01M10/52

  Removing gases inside the secondary cell, e.g. by absorption (vent plugs or other mechanical arrangements for facilitating escape of gases H01M50/30) · CPC title

• H01M10/44 Primary

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• H01M4/0447

  of complete cells or cells stacks · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title