Current separation method, prediction method, system and like of nonaqueous lithium power storage element

Patent metadata

Field	Value
Publication number	US-12580137-B2
Application number	US-202218025506-A
Country	US
Kind code	B2
Filing date	May 30, 2022
Priority date	Dec 10, 2021
Publication date	Mar 17, 2026
Grant date	Mar 17, 2026

Abstract

The present disclosure relates to a current separation method and the like of a nonaqueous lithium power storage element. In the current separation method, the nonaqueous lithium power storage element includes a cell including: a positive electrode precursor that includes a positive electrode active material layer containing lithium carbonate and activated carbon; a negative electrode that includes a negative electrode active material layer containing a negative electrode active material capable of occluding and releasing lithium; a separator arranged between the positive electrode precursor and the negative electrode; and an electrolyte solution. The current separation method includes the step of calculating a capacitor current I C and an electrode reaction current I d of the cell based on voltage and current of the cell that are measured during doping of the cell.

First claim

The invention claimed is:

1 . A method for predicting performance of a nonaqueous lithium power storage element, wherein the nonaqueous lithium power storage element comprises a cell comprising: a positive electrode precursor that comprises a positive electrode active material layer comprising lithium carbonate and activated carbon; a negative electrode that comprises a negative electrode active material layer comprising a negative electrode active material capable of occluding and releasing lithium; a separator arranged between the positive electrode precursor and the negative electrode; and an electrolyte solution, wherein the method comprises:
(1) a doping condition setting step of setting doping conditions including input current or input voltage; (2) a measurement step of measuring a positive electrode potential E (V) and a bulk current density i (A/m 2 ) of the cell while applying the input current or the input voltage to the cell; (3) a current calculation step of, with an assumed positive electrode potential E (V) assumed at the time of modifying the system time by Δt based on the measured positive electrode potential E (V) of the cell, calculating a capacitor current I C (A) of the cell by the following equation, calculating a capacitor current density i C (A/m 2 ) of the cell by dividing the capacitor current I C (A) by a positive electrode precursor area (m 2 ), and calculating, based on the Butler-Volmer equation and the diffusion equation, a current density i R1 (A/m 2 ) of an electrode reaction 1 which is a main reaction in which lithium carbonate is decomposed to release lithium ions and electrons, as well as current densities i R2 (A/m 2 ) to i RN (A/m 2 ) of electrode reactions 2 to N (wherein, N represents an integer of 3 or larger) which are side reactions:

[

Math
.

2

]

I
C

=

C
⁢

dE
dt

{wherein, I C represents the capacitor current (A); C represents a capacitor capacity (F/m 2 ) of the cell; E represents the assumed positive electrode potential E (V); and t represents time(s)};
(4) a positive electrode potential correction step of correcting the assumed positive electrode potential E (V) such that a total current density of the capacitor current density i C and the current densities i R1 to i RN of the respective electrode reactions is equal to the bulk current density i, and thereby obtaining a corrected positive electrode potential E (V); and
(5) a current separation step of repeating the steps (3) and (4) while modifying the system time such that the total current density converges to the bulk current density i,
(6) a parameter calculation step of calculating at least one parameter selected from the group of parameters consisting of an integrated capacity parameter of the capacitor current I C (A), a positive electrode potential change parameter of a current capacity Q (mAh) of the capacitor current I C (A), and a temporal change parameter of the positive electrode potential E (V), in a constant-current (CC) charged region; and
(7) a prediction step of inputting the thus calculated parameter to a learned model which has learned the correlations between the group of parameters and the performance of the nonaqueous lithium power storage element, and outputting the performance of the nonaqueous lithium power storage element, which performance includes at least one selected from the group consisting of cell capacity, cell resistance, and self-discharge performance,
wherein
in the parameter calculation step, at least one parameter selected from the group of parameters is calculated based on the capacitor current I C (A) calculated from the assumed positive electrode potential E (V), or based on the corrected positive electrode potential E (V).

2 . The prediction method according to claim 1 , wherein parameters of the group of parameters are each calculated in a positive electrode potential E (V) range of x (V) to y (V) {wherein, x and y are each independently 3.3 V to 3.8 V and satisfy x<y} in the constant-current (CC) charged region.

3 . The prediction method according to claim 1 , wherein the calculations in the step (3) are performed based on the following standards:
(i) in a case where the measured positive electrode potential E (V) is lower than an onset potential of an electrode reaction x (wherein, x corresponds to 1 to N), the current density i Rx of the electrode reaction x is not generated (0 A/m 2 ); (ii) in a case where the measured positive electrode potential E (V) is equal to or higher than the onset potential of the electrode reaction x, the current density of the electrode reaction x is determined by the Butler-Volmer equation and, when the thus determined current density is lower than a limiting current density of the electrode reaction x, this current density is defined as the current density i Rx of the electrode reaction x; and (iii) in a case where the current density determined based on the above-described (ii) is equal to or higher than the limiting current density of the electrode reaction x, a current density determined by the diffusion equation and the Butler-Volmer equation is defined as the current density i Rx of the electrode reaction x.

4 . A method of producing a nonaqueous lithium power storage element, the method comprising predicting at least one performance selected from the group consisting of cell capacity, cell resistance, and self-discharge performance by the prediction method according to claim 1 at the time of doping the nonaqueous lithium power storage element, and not performing an inspection of the thus predicted performance.

5 . A method for predicting durability performance of a nonaqueous lithium power storage element, wherein the nonaqueous lithium power storage element comprises a cell comprising: a positive electrode precursor that comprises a positive electrode active material layer comprising lithium carbonate and activated carbon; a negative electrode that comprises a negative electrode active material layer comprising a negative electrode active material capable of occluding and releasing lithium; a separator arranged between the positive electrode precursor and the negative electrode; and an electrolyte solution, wherein the method comprises:
(1) a doping condition setting step of setting doping conditions including input current or input voltage; (2) a measurement step of measuring the positive electrode potential E (V) and a bulk current I (A) of the cell while applying the input current or the input voltage to the cell; (3) a current calculation step of, with an assumed positive electrode potential E (V) assumed at the time of modifying the system time by Δt based on the measured positive electrode potential E (V) of the cell, calculating a capacitor current I C (A) and a electrode reaction current I d (A) of the cell by the following equations, calculating a bulk current density i (A/m 2 ) and a capacitor current density i C (A/m 2 ) by dividing the bulk current I (A) and the capacitor current I C (A) by a positive electrode precursor area (m 2 ), respectively, and calculating, based on the Butler-Volmer equation and the diffusion equation, a current density i R1 (A/m 2 ) of an electrode reaction 1 which is a main reaction in which lithium

Assignees

• Asahi Chemical Ind

Inventors

• Hiraoka Koichi
• Nakamura Fumiya
• Okoshi Ryusuke
• Morikawa Yusuke

Classifications

• H01G11/86

  specially adapted for electrodes (carbonisation or activation of carbon for the manufacture of electrodes H01G11/34) · CPC title

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title

• H01G11/08

  Structural combinations, e.g. assembly or connection, of hybrid or EDL capacitors with other electric components, at least one hybrid or EDL capacitor being the main component · CPC title

• H01G11/06

  with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC] · CPC title

• G06N20/00

  Machine learning · CPC title