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KR-20260062629-A - FORMATION METHOD FOR SECONDARY BATTERY AND MANUFACTURING METHOD FOR SECONDARY BATTERY USING THE SAME

KR20260062629AKR 20260062629 AKR20260062629 AKR 20260062629AKR-20260062629-A

Abstract

A method for forming a secondary battery according to the present disclosure may include a first injection step of injecting a first electrolyte into a secondary battery cell in which an electrode assembly comprising a positive electrode, a negative electrode, and a separator is housed in a battery case; a charging step of charging the secondary battery cell into which the first electrolyte has been injected; a second injection step of injecting a second electrolyte into the secondary battery cell; and a discharging step of discharging the secondary battery cell into which the second electrolyte has been injected.

Inventors

  • 문주호

Assignees

  • 에스케이온 주식회사

Dates

Publication Date
20260507
Application Date
20241029

Claims (17)

  1. A first injection step of injecting a first electrolyte into a secondary battery cell in which an electrode assembly including a positive electrode, a negative electrode, and a separator is housed in a battery case; A charging step for charging a secondary battery cell into which a first electrolyte has been injected; A second injection step of injecting a second electrolyte into the secondary battery cell; and A discharge step for discharging a secondary battery cell into which a second electrolyte has been injected; comprising Method for forming a secondary battery.
  2. In paragraph 1, The first electrolyte above comprises a lithium salt, an organic solvent, and a first additive, and A method for forming a secondary battery, wherein the first additive comprises at least one selected from the group consisting of cyclic carbonate compounds, fluorine-substituted carbonate compounds, sulfone compounds, cyclic sulfate compounds, cyclic sulfite compounds, phosphate compounds, and borate compounds.
  3. In paragraph 2, A method for forming a secondary battery, wherein the first electrolyte comprises 2.0 to 3.0 weight percent of the first additive based on the total weight of the first electrolyte and the second electrolyte.
  4. In paragraph 2, A method for forming a secondary battery, wherein the organic solvent of the first electrolyte comprises at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethylmethyl carbonate (EMC).
  5. In paragraph 1, A method for forming a secondary battery, wherein the first injection step further comprises the step of injecting the first electrolyte into the secondary battery cell and then aging at a temperature of 20 to 30°C for 12 to 36 hours.
  6. In paragraph 1, A method for forming a secondary battery, wherein the charging step is to charge the secondary battery cell to a state of charge (SOC) of 50 to 100%.
  7. In paragraph 1, A method for forming a secondary battery, wherein the above charging step involves applying a current in a C-rate range of 0.1 to 0.5C.
  8. In paragraph 1, The second electrolyte above comprises a lithium salt, an organic solvent, and a second additive, and A method for forming a secondary battery, wherein the second additive comprises at least one of the compounds represented by the following chemical formula 1: [Chemical Formula 1] A x B y In the above chemical formula 1, A is one selected from the group consisting of Mg, V, Ti, Al, Mn, Fe, Ni, Co and Nb, B is one selected from the group consisting of O, NO3 and SO4 , 0<x≤2, and 0<y≤5.
  9. In paragraph 8, A method for forming a secondary battery, wherein the second additive further comprises at least one selected from the group consisting of vinylene carbonate (VC), 1,3-propane sultone, and 1,2-ethylene sulfate.
  10. In paragraph 8, A method for forming a secondary battery, wherein the organic solvent of the second electrolyte comprises at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethylmethyl carbonate (EMC).
  11. In paragraph 8, A method for forming a secondary battery, wherein the second electrolyte comprises 1.0 to 2.0 weight% of the second additive based on the total weight of the first electrolyte and the second electrolyte.
  12. In paragraph 1, A method for forming a secondary battery, wherein the second electrolyte is injected at a weight of 10 to 30% based on the total weight of the first electrolyte and the second electrolyte.
  13. In paragraph 1, A method for forming a secondary battery, wherein the second injection step further comprises the step of injecting the second electrolyte into the secondary battery cell and then aging at a temperature of 20 to 30°C for 6 to 12 hours.
  14. In paragraph 1, A method for forming a secondary battery, wherein the above discharge step is to discharge the secondary battery cell to an SOC of 0 to 0.1%.
  15. In paragraph 1, A method for forming a secondary battery, wherein the above discharge step involves applying a current in a C-rate range of 0.3 to 0.5C.
  16. In paragraph 1, A method for forming a secondary battery, wherein the above-mentioned positive electrode comprises a positive electrode active material, and the above-mentioned positive electrode active material comprises a lithium metal phosphate-based active material represented by the following chemical formula 2. [Chemical Formula 2] Li a M x P y O 4+z (In Chemical Formula 2, 0.9≤a≤1.2, 0.99≤x≤1.01, 0.9≤y≤1.2, -0.1≤z≤0.1, and M comprises at least one selected from the group consisting of Fe, Co, Ni, and Mn).
  17. A method for manufacturing a lithium secondary battery comprising a formation step performed by a formation method according to any one of claims 1 to 16.

Description

Formation method for secondary battery and manufacturing method for secondary battery using the same The present disclosure relates to a method for forming a secondary battery and a method for manufacturing a secondary battery using the same. Recently, rechargeable secondary batteries are being widely used as energy sources or auxiliary power devices for wireless mobile devices. Furthermore, secondary batteries are attracting attention as a power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (Plug-In HEVs), which are being proposed as solutions to address air pollution caused by conventional gasoline and diesel vehicles that use fossil fuels. These secondary batteries can be manufactured through a formation process that stabilizes the battery structure and makes it usable by charging and discharging the assembled battery. In this regard, due to the recent trend toward higher capacity and performance in secondary batteries, the formation method used in the process is also becoming increasingly important. Therefore, research on formation methods for secondary batteries that can improve their performance and stability is required. FIG. 1 is a flowchart of a method for forming a secondary battery according to one embodiment of the present disclosure. Hereinafter, the technology disclosed in this specification and its embodiments are described in detail. However, the embodiments of the technology may be modified in various different forms, and their scope is not limited to the embodiments described below. Furthermore, the technology disclosed in this specification may not only be applied in a limited manner to the configurations of the embodiments described below, but may also be configured by selectively combining all or part of each embodiment to allow for various modifications. As described above, research is required on a formation method for secondary batteries that can improve the performance and stability of the secondary battery. According to one embodiment, to improve the performance of the secondary battery, various performance-enhancing additives are added to the electrolyte, and after sealing or temporarily sealing the cell, a formation process can be carried out. When additives are introduced all at once in this manner, they may be simultaneously applied to both the cathode and anode active materials during the initial stage of the formation process (charge formation). In this case, problems may arise where unintended reactions occur and resulting products are formed. Consequently, the products resulting from the reactions intended by the additives are formed relatively less, which can significantly reduce the effectiveness achievable through the additives. On the other hand, a method for forming a secondary battery according to one embodiment of the present disclosure involves injecting an electrolyte containing an additive capable of improving the performance of the negative electrode before a charging step in which electrons move to the negative electrode, and then proceeding with charging; and injecting an electrolyte containing an additive capable of improving the performance of the positive electrode before a discharging step in which electrons move to the positive electrode, and then proceeding with discharging. Accordingly, a Solid Electrolyte Interphase (SEI) layer can be effectively formed on the surface of the negative electrode through charging, and a Cathode Electrolyte Interphase (CEI) layer can be effectively formed on the surface of the positive electrode through discharging, or the performance of the positive electrode can be effectively improved by coating or doping a positive electrode active material. Specifically, a method for forming a secondary battery according to one embodiment of the present disclosure may include: a first injection step of injecting a first electrolyte into a secondary battery cell in which an electrode assembly comprising a positive electrode, a negative electrode, and a separator is housed in a battery case; a charging step of charging the secondary battery cell into which the first electrolyte has been injected; a second injection step of injecting a second electrolyte into the secondary battery cell; and a discharging step of discharging the secondary battery cell into which the second electrolyte has been injected. FIG. 1 is a flowchart of a formation method according to one embodiment of the present disclosure. Hereinafter, a formation method for a secondary battery according to the present disclosure will be described in more detail with reference to FIG. 1. First injection stage The formation method according to the present disclosure may include a first injection step (S10) of injecting a first electrolyte into a secondary battery cell in which an electrode assembly comprising a positive electrode, a negative electrode, and a separator is housed in a battery case. The first electrolyte ma