US 12,222,401 B2
Method of diagnosing degradation of electrode active material for lithium secondary battery
Su Won Jee, Daejeon (KR); Hyo Jung Yoon, Daejeon (KR); Young Deok Kim, Daejeon (KR); Ji Yeon Kim, Daejeon (KR); and Dae Soo Kim, Daejeon (KR)
Assigned to LG Energy Solution, Ltd., Seoul (KR)
Appl. No. 17/774,666
Filed by LG Energy Solution, Ltd., Seoul (KR)
PCT Filed Jan. 12, 2021, PCT No. PCT/KR2021/000411
§ 371(c)(1), (2) Date May 5, 2022,
PCT Pub. No. WO2021/149960, PCT Pub. Date Jul. 29, 2021.
Claims priority of application No. 10-2020-0007495 (KR), filed on Jan. 20, 2020.
Prior Publication US 2022/0397613 A1, Dec. 15, 2022
Int. Cl. G01R 31/392 (2019.01); G01R 31/36 (2020.01); G01R 31/385 (2019.01); H01M 4/38 (2006.01); H01M 4/485 (2010.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 10/052 (2010.01); H01M 10/44 (2006.01); H01M 4/02 (2006.01)
CPC G01R 31/392 (2019.01) [G01R 31/3646 (2019.01); G01R 31/3865 (2019.01); H01M 4/386 (2013.01); H01M 4/485 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 10/052 (2013.01); H01M 10/446 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method of diagnosing degradation by beta phase formation of an electrode active material for a secondary battery, comprising:
preparing a lithium secondary battery which includes a positive electrode including a positive electrode active material of a lithium transition metal oxide containing nickel (Ni) in an amount of 60 mol % or more based on a total number of moles of transition metals except lithium, and a negative electrode facing the positive electrode;
performing first charging and first discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, measuring an initial charge/discharge curve of the lithium secondary battery, and then differentiating the initial charge/discharge curve to obtain a first differential curve (dQ/dV) of the lithium secondary battery;
performing second charging and second discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, measuring a second charge/discharge curve of the lithium secondary battery, and then differentiating the second charge/discharge curve to obtain a second differential curve (dQ/dV) of the lithium secondary battery, and
diagnosing that a beta phase of the positive electrode active material has been formed by determining when spaced-apart peaks are observed at 4.0 V or more with a maximum discharge peak value of the second differential curve at 4.0 V or more compared to a maximum discharge peak value of at 4.0 V or more of the first differential curve is spaced apart within a range of 0.01 V to 0.1 V.