CN-121990531-A - Recycling method of lithium ion battery

Abstract

The invention aims to suppress the influence of sulfur components originating from salts of an electrolyte when a positive electrode active material is recovered from a positive electrode mixture. A method for recycling a lithium ion battery using LiFSI as a salt of an electrolyte solution, comprising a treatment agent mixing step of mixing lithium carbonate into a positive electrode mixture recovered from a waste lithium ion battery, and a heating step of heating a mixture obtained by mixing lithium carbonate into the positive electrode mixture to a heating temperature equal to or higher than the melting point of LiFSI and equal to or lower than the melting point of lithium carbonate.

Inventors

• Hengshan Mountain friend is grand

Assignees

• 丰田自动车株式会社

Dates

Publication Date

20260508

Application Date

20251105

Priority Date

20241108

Claims (3)

1. 1. A method for recycling a lithium ion battery using LiFSI as a salt of an electrolyte, comprising: a mixing step of mixing lithium carbonate into a positive electrode mixture recovered from the waste lithium ion battery, and And a heating step of heating a mixture obtained by mixing the lithium carbonate with the positive electrode mixture to a heating temperature equal to or higher than the melting point of the LiFSI and equal to or lower than the melting point of the lithium carbonate.
2. 2. The method for recycling lithium-ion battery according to claim 1, wherein, In the mixing step, the inorganic salt mixed in the positive electrode mixture is only the lithium carbonate.
3. 3. The method for recycling lithium-ion battery according to claim 2, wherein, The heating temperature in the heating step is a temperature equal to or higher than the thermal decomposition temperature of LiFSI.

Description

Recycling method of lithium ion battery Technical Field The invention relates to a recycling method of a lithium ion battery. Background Patent document 1 discloses a method for recycling a lithium ion battery, in which an active material is recovered using an electrode mixture obtained from a waste electrode, the method including a mixing step of mixing an activation treatment agent into a positive electrode mixture, and a heating step of heating the mixture to a temperature equal to or higher than the melting start temperature of the activation treatment agent. The structure described in patent document 1 includes an active material recovery step of recovering an active material from a mixture after the heating step. The active material recovery step uses a slurrying solid-liquid separation method for separating and recovering an active material from a mixture subjected to a heating step, and includes a slurrying step, a solid-liquid separation step, a drying step, and a re-calcination step. Patent document 1 Japanese patent application laid-open No. 2021-140996 Disclosure of Invention In the structure described in patent document 1, the activation treatment agent in a molten state is brought into contact with the fluorine compound derived from the electrolyte, so that the fluorine component is stabilized to an alkali metal fluoride, and the generation of hydrogen fluoride can be prevented, and deterioration of the crystal structure of the active material can be suppressed. In lithium ion batteries, it is known to use an electrolyte comprising LiFSI (lithium bis (fluorosulfonyl) imide). In the structure described in patent document 1, liPF 6 (lithium hexafluorophosphate) is used as a salt of the electrolyte. In a lithium ion battery using LiFSI as a salt of an electrolyte, a sulfur component remains in a positive electrode mixture after charge and discharge. In the structure described in patent document 1, it is assumed that the fluorine component derived from the electrolyte is contained in the mixture after heating, and the deterioration of the active material due to the fluorine component is suppressed, but the influence by the sulfur component derived from the electrolyte is not considered. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for recycling a lithium ion battery capable of suppressing the influence of sulfur components originating from salts of an electrolyte when a positive electrode active material is recovered from a positive electrode mixture. The invention provides a method for recycling a lithium ion battery, which is characterized by comprising a mixing step of mixing lithium carbonate into a positive electrode mixture recovered from a waste lithium ion battery, and a heating step of heating a mixture obtained by mixing the lithium carbonate into the positive electrode mixture to a heating temperature which is higher than the melting point of LiFSI and lower than the melting point of lithium carbonate. Effects of the invention In the present invention, the influence of the sulfur component of the salt derived from the electrolyte can be suppressed when the positive electrode active material is recovered from the positive electrode mixture. Drawings Fig. 1 is a flowchart showing a method for recycling a lithium ion battery according to an embodiment. Fig. 2 is a graph showing the sulfur concentration in the recovered product with respect to the combination of the type of the treating agent and the treating temperature. Detailed Description Hereinafter, a method for recycling a lithium ion battery according to an embodiment of the present invention will be specifically described. The present invention is not limited to the embodiments described below. The method for recycling a lithium ion battery in the embodiment is directed to a lithium ion battery using LiFSI as a salt of an electrolyte. The reuse method is a method for removing sulfur components contained in a positive electrode mixture and regenerating a positive electrode active material when the positive electrode active material is recovered from a waste lithium ion battery. The positive electrode active material may be either of an olivine type and a layered type. The method for recycling a lithium ion battery according to the embodiment is a material recycling method in direct recycling in which an active material is regenerated without being recovered as a raw material. If the sulfur component contained in the electrolyte remains in the recovered active material by direct reuse, the capacity, performance and quality of the battery may be reduced. Since LiFSI contained in the electrolyte is dissolved in water, it should be easily removed by water washing, but easily remain in the regenerated active material, and the sulfur component cannot be reduced to the same level as that of the new active material by water washing or ultrasonic cleanin