Manufacturing method of lithium ion battery and lithium ion battery

Abstract

The invention discloses a manufacturing method of a lithium ion battery and the lithium ion battery, and the manufacturing method of the lithium ion battery comprises the following steps: injecting a titanium metal solution in the process of manufacturing the lithium ion battery to improve the impedance of the lithium ion battery; wherein the titanium metal solution comprises titanium metal and a hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8 wt%. According to the manufacturing method of the lithium ion battery, the impedance of the lithium ion battery can be reduced, so that the capacity of the lithium ion battery is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for manufacturing a lithium ion battery and a lithium ion battery. Background Art

[0002] In the process of new energy battery research and development in current technology, the existence of interface side reactions during the cycle of lithium-ion batteries will lead to continuous decomposition of electrolyte at the positive and negative electrode interfaces, as well as phase change of the positive electrode active material interface, thereby causing loss of active Li and increase in lithium-ion battery impedance. Therefore, it is very necessary to provide a method for manufacturing a lithium-ion battery and a lithium-ion battery that can reduce the impedance of a lithium-ion battery. Summary of the invention

[0003] The purpose of the present invention is to solve the above problems and provide a method for manufacturing a lithium ion battery and a lithium ion battery. The method for manufacturing a lithium ion battery of the present invention can reduce the impedance of the lithium ion battery and thereby increase the capacity of the lithium ion battery.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a method for manufacturing a lithium-ion battery, comprising the steps of: injecting a titanium metal solution during the process of manufacturing the lithium-ion battery to improve the impedance of the lithium-ion battery; wherein the titanium metal solution comprises titanium metal and a hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%.

[0006] Optionally, the ratio of the amount of the titanium metal solution injected into the lithium ions to the amount of the electrolyte is 1:3-1:5, measured in parts by mass.

[0007] Optionally, the hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0 wt % of the total amount of the hydrofluoric acid solution.

[0008] Optionally, the lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

[0009] Optionally, the electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate.

[0010] In a second aspect, the present invention provides a lithium-ion battery, which is prepared by the manufacturing method as described above; a titanium metal solution is injected into the lithium-ion battery to improve the impedance of the lithium-ion battery; wherein the titanium metal solution includes titanium metal and hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%.

[0011] Optionally, the ratio of the amount of the titanium metal solution injected into the lithium ions to the electrolyte is 1:3-1:5, measured in parts by mass.

[0012] Optionally, the hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0 wt % of the total amount of the hydrofluoric acid solution.

[0013] Optionally, the lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

[0014] Optionally, the electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate.

[0015] The beneficial effects produced by the present invention include at least:

[0016] In the manufacturing method of the lithium ion battery described in the present invention, a titanium metal solution is injected into the lithium ion battery, and the titanium metal in the titanium metal solution reacts with hydrofluoric acid and sulfuric acid to generate titanium complex ion compounds, thereby producing more current collectors and reducing impedance; and the formed titanium metal solution is integrated into the electrolyte, and electrons are actively accelerated during charging and discharging, and the conductivity is fast and the impedance is small, thereby forming a reduced impedance battery; in addition, in the manufacturing method described in the present invention, the titanium metal solution is injected into the lithium ion battery, and from the overall point of view, the original volume of the lithium battery is not changed, and it can even reduce the volume, increase the capacity, and improve the production efficiency. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively in conjunction with specific embodiments below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in the present invention. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] Unless otherwise specified, the raw materials involved in the present invention can be obtained from suppliers known in the art or prepared by known methods.

[0020] In a first aspect, the present invention provides a method for manufacturing a lithium-ion battery, comprising the steps of: injecting a titanium metal solution during the manufacturing process of the lithium-ion battery to improve the impedance of the lithium-ion battery; wherein the titanium metal solution comprises titanium metal and a hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%. Specifically, the mass percentage of the titanium metal solution can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt% or 0.8wt%.

[0021] In the manufacturing method of the lithium ion battery described in the present invention, a titanium metal solution is injected into the lithium ion battery, and the titanium metal in the titanium metal solution reacts with hydrofluoric acid and sulfuric acid to generate titanium complex ion compounds, thereby generating more current collectors and reducing impedance. Specifically, the titanium in the titanium metal solvent reacts with a hydrofluoric acid aqueous solution to generate complex ions and hydrogen: Ti(ls)+4HF(aq)→TiF4(aq)+2H2(aq), and titanium reacts with sulfuric acid: 2Ti+2H2SO4=Ti2(SO4)2+2H2↑. During the charge and discharge process, the reaction temperature inside the lithium ion battery is between 30 and 60°C, the lithium ions change rapidly, and the heat generated generates trivalent titanium. The ions are active to generate more current collectors, thereby reducing impedance. At the same time, the formed titanium metal solution is integrated into the electrolyte, and the electron activity is accelerated during charging and discharging, thereby improving the diffusion efficiency of the electrolyte, fast conductivity and low impedance, forming a reduced impedance battery; in addition, in the manufacturing method described in the present invention, the titanium metal solution is injected into the lithium-ion battery, which does not change the original volume of the lithium battery as a whole, and can even reduce the volume, increase the capacity, and improve production efficiency.

[0022] Optionally, the ratio of the amount of the titanium metal solution injected into the lithium ions to the amount of the electrolyte is 1:3-1:5 by mass. Specifically, the ratio of the amount of the titanium metal solution injected to the amount of the electrolyte added is 1:3, 1:4 or 1:5.

[0023] Optionally, the hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0wt% of the total amount of the hydrofluoric acid solution. Specifically, the amount of sulfuric acid added is 3.5wt% or 4.0wt% of the total amount of the hydrofluoric acid solution.

[0024] Optionally, the lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

[0025] Optionally, the electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate. The positive electrode material is lithium iron phosphate, the negative electrode material is graphite, and the diaphragm is a polypropylene diaphragm.

[0026] In a second aspect, the present invention provides a lithium-ion battery, which is prepared by the manufacturing method as described above; a titanium metal solution is injected into the lithium-ion battery to improve the impedance of the lithium-ion battery; wherein the titanium metal solution includes titanium metal and hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%.

[0027] Optionally, the ratio of the amount of the titanium metal solution injected into the lithium ions to the electrolyte is 1:3-1:5, measured in parts by mass.

[0028] Optionally, the hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0 wt % of the total amount of the hydrofluoric acid solution.

[0029] Optionally, the lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

[0030] Optionally, the electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate. The positive electrode material is lithium iron phosphate, the negative electrode material is graphite, and the diaphragm is a polypropylene diaphragm.

[0031] Example 1: A lithium-ion battery is manufactured by the above-mentioned manufacturing method. The ratio of the amount of titanium metal solution injected into the lithium-ion battery to the electrolyte is 1:3, the solubility of the titanium metal solution is 0.2-0.5wt%, and the amount of sulfuric acid added to the hydrofluoric acid solution is 3.6wt%. When used, the titanium metal is dissolved in the hydrofluoric acid solution, stirred evenly, and then injected into the lithium-ion battery.

[0032] Comparative Example 1: Compared with Example 1, the specifications of the lithium-ion battery provided in Comparative Example 1 are the same, except that the titanium metal solution of the present invention is injected into Comparative Example 1.

[0033] After testing, the resistivity of the lithium ion battery obtained in Example 1 at a temperature of 20°C is 42*10mΩ, which is 5% mΩ lower than that of the lithium ion battery provided in Comparative Example 1. This indicates that the impedance of the lithium ion battery is reduced by injecting a titanium metal solution using the lithium ion battery manufacturing method of the present invention.

[0034] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for manufacturing a lithium-ion battery, characterized in that: The method comprises the following steps: injecting a titanium metal solution during the process of manufacturing a lithium ion battery to improve the impedance of the lithium ion battery; wherein the titanium metal solution comprises titanium metal and a hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%.

2. The method for manufacturing a lithium-ion battery according to claim 1, characterized in that: In terms of mass fraction, the ratio of the amount of the titanium metal solution injected into the lithium ions to the electrolyte is 1:3-1:

5.

3. The method for manufacturing a lithium-ion battery according to claim 1, characterized in that: The hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0 wt % of the total amount of the hydrofluoric acid solution.

4. The method for manufacturing a lithium-ion battery according to claim 1, characterized in that: The lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

5. The method for manufacturing a lithium-ion battery according to claim 2, characterized in that: The electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate.

6. A lithium ion battery, characterized in that: The lithium-ion battery is prepared by the manufacturing method according to any one of claims 1 to 5; a titanium metal solution is injected into the lithium-ion battery to improve the impedance of the lithium-ion battery; wherein the titanium metal solution includes titanium metal and hydrofluoric acid solution, and the mass percentage of the titanium metal solution is 0.2-0.8wt%.

7. The lithium-ion battery according to claim 6, characterized in that: In terms of mass fraction, the ratio of the amount of the titanium metal solution injected into the lithium ions to the electrolyte is 1:3-1:

5.

8. The lithium-ion battery according to claim 6, characterized in that The hydrofluoric acid solution includes hydrofluoric acid and sulfuric acid, and the amount of sulfuric acid added is 3.5-4.0 wt % of the total amount of the hydrofluoric acid solution.

9. The lithium-ion battery according to claim 6, characterized in that: The lithium-ion battery also includes a positive electrode material, a negative electrode material, an electrolyte, a diaphragm and a shell; the positive electrode material, the negative electrode material, the diaphragm and the electrolyte are all contained in the shell, the diaphragm is arranged between the positive electrode material and the negative electrode material, and the electrolyte is filled in the shell.

10. The lithium ion battery according to claim 7, characterized in that: The electrolyte includes one or more of ethylene carbonate, propylene carbonate or diethyl carbonate.