Preparation method of cylindrical sodium ion battery

Abstract

The invention discloses a preparation method of a cylindrical sodium ion battery. The preparation method comprises the following steps: firstly, respectively homogenizing, coating, drying, rolling and slitting a negative electrode material and a positive electrode material; carrying out tab welding and winding on the obtained pole piece, and welding a steel shell; then baking the naked battery cell, injecting liquid and standing; and finally performing formation, aging, capacity grading and performance testing on the obtained battery cell. According to the method for adding the water-based adhesive into the negative electrode provided by the invention, the conditions of battery performance collapse and inconsistent performance caused by powder falling and falling of an electrode material are avoided; according to the method for adding the organic acid into the positive electrode material provided by the invention, the situation that the battery performance is reduced or even collapsed due to overhigh resistance caused by overhigh moisture and collapse of the electrode material is avoided; according to the full-tab laser welding method provided by the invention, the electrochemical performance of the battery is improved. The method provided by the invention not only can produce the cylindrical sodium ion battery with uniform and stable performance, but also is simple in production process and relatively short in preparation flow.

Description

Technical Field

[0001] This invention relates to a method for preparing a battery, and more particularly to a method for preparing a cylindrical sodium-ion battery. Background Technology

[0002] With the development of electric vehicles and energy storage technologies, the standard for evaluating batteries is no longer solely focused on high capacity, leading to a significant expansion of the battery energy storage market. Limited by the scarcity and high cost of lithium resources, sodium-ion batteries, with their abundant sodium reserves and low cost, possess considerable market and economic value.

[0003] However, compared to lithium-ion batteries, sodium-ion batteries are slightly inferior in terms of capacity and energy density, but they have advantages in rate performance, low-temperature performance, and safety. Therefore, it is particularly important to develop sodium-ion batteries with high rate performance, excellent low-temperature performance, and high safety to compensate for the shortcomings of lithium-ion batteries in specific scenarios and to maximize the application areas of sodium-ion batteries. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a cylindrical sodium-ion battery, which can not only produce a cylindrical sodium-ion battery with uniform and stable performance, but also has a simple production process and a short preparation process.

[0005] The technical solution adopted in this invention is: a method for manufacturing a cylindrical sodium-ion battery, comprising the following steps:

[0006] (1) The negative electrode material is homogenized, coated, dried, rolled and slit. The negative electrode material is composed of hard carbon, conductive carbon black, binder, dispersant and solvent. The solvent is water solvent, the dispersant is CMC and the binder is one or more of SBR and PAA.

[0007] (2) The positive electrode material is homogenized, coated, dried, rolled and slit. The positive electrode material is composed of sodium nickel cobalt manganese oxide, conductive carbon black, binder, dispersant and solvent, wherein the solvent is NMP solvent, the dispersant is CMC and the binder is one or more of PVDF and SBR.

[0008] (3) The electrode sheets obtained in steps (1) and (2) are subjected to electrode tab welding, winding, and steel shell welding;

[0009] (4) The bare battery cell obtained in step (3) is baked, injected with electrolyte, and left to stand. The electrolyte is composed of sodium hexafluorophosphate and additives, wherein the additives include one or more of ethylamine, methylamine, and ethylamine.

[0010] (5) The cells obtained in step (4) after being left to stand are formed, aged, tested for capacity and performance.

[0011] One or more organic acids, such as acetic acid, oxalic acid, and acetic acid, were added to the homogenized material in step (2).

[0012] In the negative or positive electrode material, the proportion of hard carbon or sodium nickel cobalt manganese oxide is 90-96%, the proportion of conductive carbon black is 0.5-1.5%, and the proportion of binder is 1-3%; in the materials and solvents.

[0013] In step (3), the tab welding is full tab laser welding, the winding is automatic correction winding, and the diaphragm used is single-sided ceramic PP or PET.

[0014] The baking or drying temperature in steps (1), (2), and (4) is between 50 and 95°C, and the baking or drying time is between 24 and 72 hours.

[0015] The surface density of the coating on one side in step (1) is 40-70 g / m². 2 The surface density of the coating on one side in step (2) is 100-180 g / m². 2 .

[0016] In step (1), the roller pressing pressure is between 3-7T, the roller pressing speed is between 5-20cm / s, and the resulting compacted density is between 0.6-1.0g / cm³. 3 The rolling pressure in step (2) is between 3-7T, the rolling speed is between 10-30cm / s, and the resulting compacted density is between 2.5-3.5g / cm³. 3 between.

[0017] In step (4), the moisture content of the bare battery cell after baking is between 100-500 ppm; the amount of additive added to the electrolyte in step (4) is between 1-5%; the water and oxygen content of the injected electrolyte in step (4) is required to be between 0-0.5 ppm for oxygen content and between 0-0.5 ppm for water content; the static activation temperature in step (4) is between 30-60℃ and the static time is between 24-72 hours.

[0018] In step (5), the chemical conversion is carried out at different rates of constant current and constant voltage to 60-80%; the aging temperature in step (5) is between 60-95℃ and the time is between 24-72 hours; in step (5), the constant current and constant voltage charge and discharge are carried out.

[0019] In steps (1)-(5), the temperature is between 15-25℃ and the humidity is between 1-10%.

[0020] The technical effects of this invention are:

[0021] 1. The method proposed in this invention can not only produce cylindrical sodium-ion batteries with uniform and stable performance, but also has a simple production process and a short preparation process, providing a solution for the rapid production of cylindrical sodium-ion batteries.

[0022] 2. The method of adding water-based adhesive to the negative electrode proposed in this invention allows the negative electrode material to adhere tightly to the current collector, avoiding the collapse of battery performance and inconsistent performance caused by electrode material shedding or falling off.

[0023] 3. The method of adding organic acid to the positive electrode material proposed in this invention can effectively prevent the positive electrode material from absorbing water, thereby avoiding excessive resistance caused by excessive moisture and the collapse of the electrode material, which would lead to a decrease in battery performance or even collapse.

[0024] 4. The all-tab laser welding method proposed in this invention can effectively reduce the internal resistance of the battery, thereby improving the electrochemical performance of the battery. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the coating process in the method for preparing a cylindrical sodium-ion battery according to the present invention.

[0026] Figure 2 This is a schematic diagram of the winding process in the method for preparing a cylindrical sodium-ion battery according to the present invention.

[0027] Figure 3 The rate performance diagram of the cylindrical sodium-ion battery prepared according to the present invention is shown.

[0028] Figure 4 The capacity retention rate of the cylindrical sodium-ion battery prepared according to the present invention at different rates. Detailed Implementation

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] See Figure 1 This is a schematic diagram of coating the prepared negative and positive electrode materials. Figure 2 This is a schematic diagram of the electrode winding. Figure 3 , Figure 4 This is a schematic diagram illustrating the performance of the battery obtained by the preparation method of the present invention. The following description includes three embodiments.

[0031] Example 1

[0032] (1) Dissolve hard carbon, conductive carbon black, dispersant CMC and binder SBR in water solvent in a ratio of 90:4:3:3 and disperse evenly;

[0033] (2) The slurry obtained in step (1) is applied on a coating machine, with a single-sided surface density of 40 g / m². 2;

[0034] (3) The electrode obtained in step (2) is baked at 80°C for 36 hours;

[0035] (4) The dried electrode obtained in step (3) is rolled at a pressure of 4T and a rolling speed of 10cm / s, resulting in a compaction density of 0.6g / cm³. 3 ;

[0036] (5) Dissolve sodium nickel cobalt manganate, conductive carbon black, PVDF binder and acetic acid in NMP solvent in a ratio of 92:3:4:1 and disperse evenly.

[0037] (6) The slurry obtained in step (5) is applied on a coating machine, with a single-sided surface density of 100 g / m². 2 ;

[0038] (7) The electrode obtained in step (6) is baked at 80°C for 36 hours;

[0039] (8) The dried electrode sheet obtained in step (3) is rolled at a pressure of 5T and a rolling speed of 15cm / s, resulting in a compaction density of 2.8g / cm³. 3 .

[0040] (9) The electrode sheets obtained in steps (4) and (8) are subjected to electrode tab welding, winding, and steel shell welding. The electrode tab welding is full electrode tab laser welding, the winding is automatic correction winding, and the diaphragm used is single-sided ceramic PP.

[0041] (10) The bare battery cell obtained in step (9) is baked at 80°C for 36 hours; the moisture content of the bare battery cell after baking is less than 200ppm.

[0042] (11) The dried battery cell from step (10) is injected with an electrolyte containing 3% acetamide in a sealed environment filled with nitrogen; the filling is completed in three stages.

[0043] (12) The battery cell obtained in step (11) is placed at 45°C for 36 hours to activate it.

[0044] (13) Charge the activated battery cell obtained in step (12) to 80% using constant current and constant voltage.

[0045] (14) The formed battery cell obtained in step (13) is aged at 80°C for 48 hours;

[0046] (15) Perform constant current and constant voltage charging and discharging on the aged cells from step (14) to classify the capacity of the battery.

[0047] Example 2

[0048] (1) Dissolve hard carbon, conductive carbon black, dispersant CMC and binder SBR in water in a ratio of 94:3:1.5:1.5 and disperse evenly;

[0049] (2) The slurry obtained in step (1) is applied on a coating machine, with a single-sided surface density of 50 g / m². 2 ;

[0050] (3) The electrode obtained in step (2) is baked at 85°C for 48 hours;

[0051] (4) The dried electrode obtained in step (3) is rolled at a pressure of 6T and a speed of 8cm / s, resulting in a compaction density of 0.58g / cm³. 3 ;

[0052] (5) Dissolve sodium nickel cobalt manganate, conductive carbon black, PVDF binder and acetic acid in NMP solvent in a ratio of 94:3:2:1 and disperse evenly.

[0053] (6) The slurry obtained in step (5) is applied on a coating machine, with a single-sided surface density of 130 g / m². 2 ;

[0054] (7) The electrode obtained in step (6) is baked at 70°C for 48 hours;

[0055] (8) The dried electrode sheet obtained in step (7) is rolled at a pressure of 7T and a rolling speed of 12cm / s, resulting in a compacted density of 3.0g / cm³. 3 .

[0056] (9) The electrode sheets obtained in steps (4) and (8) are subjected to electrode tab welding, winding, and steel shell welding. The electrode tab welding is full electrode tab laser welding, the winding is automatic correction winding, and the diaphragm used is single-sided ceramic PET.

[0057] (10) The bare battery cell obtained in step (9) is baked at 70°C for 48 hours; the moisture content of the bare battery cell after baking is less than 150ppm.

[0058] (11) The dried battery cell from step (10) is injected with an electrolyte containing 2% acetylmethylamine in a nitrogen-filled sealed environment; the filling is done in three stages.

[0059] (12) The battery cell obtained in step (11) is placed at 45°C for 48 hours to activate it.

[0060] (13) Charge the activated battery cell obtained in step (12) to 70% using constant current and constant voltage.

[0061] (14) The formed battery cell obtained in step (13) is aged at 85°C for 48 hours;

[0062] (15) Perform constant current and constant voltage charging and discharging on the aged cells from step (14) to classify the capacity of the battery.

[0063] Example 3

[0064] (1) Dissolve hard carbon, conductive carbon black, dispersant CMC and binder SBR in water in a ratio of 95:1.5:2:1.5 and disperse evenly;

[0065] (2) The slurry obtained in step (1) is applied on a coating machine, with a single-sided surface density of 55 g / m². 2 ;

[0066] (4) The electrode obtained in step (2) is baked at 70°C for 72 hours;

[0067] (4) The dried electrode sheet obtained in step (3) is rolled at a pressure of 7T and a rolling speed of 7cm / s, resulting in a compaction density of 0.62g / cm³. 3 ;

[0068] (5) Dissolve sodium nickel cobalt manganese oxide, conductive carbon black, PVDF binder, and acetic acid in NMP solvent in a ratio of 95:2:1.5:1.5 and disperse evenly;

[0069] (6) The slurry obtained in step (5) is applied on a coating machine, with a single-sided surface density of 150 g / m². 2 ;

[0070] (7) The electrode obtained in step (6) is baked at 70°C for 72 hours;

[0071] (8) The dried electrode sheet obtained in step (3) is rolled at a pressure of 7T and a rolling speed of 15cm / s, resulting in a compacted density of 3.2g / cm³. 3 .

[0072] (9) The electrode sheets obtained in steps (4) and (8) are subjected to electrode tab welding, winding, and steel shell welding. The electrode tab welding is full electrode tab laser welding, the winding is automatic correction winding, and the diaphragm used is single-sided ceramic PET.

[0073] (10) The bare battery cell obtained in step (9) is baked at 70°C for 72 hours; the moisture content of the bare battery cell after baking is less than 100ppm;

[0074] (11) The dried battery cell from step (10) is injected with an electrolyte containing 1.5% acetylmethylamine in a nitrogen-filled sealed environment; the filling is done in three stages.

[0075] (12) The battery cell obtained in step (11) is placed at 45°C for 72 hours to activate it.

[0076] (13) Charge the activated battery cell obtained in step (12) to 75% under constant current and constant voltage.

[0077] (14) The formed battery cell obtained in step (13) is aged at 85°C for 72 hours;

[0078] (15) Perform constant current and constant voltage charging and discharging on the aged cells from step (14) to classify the capacity of the battery.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for manufacturing a cylindrical sodium-ion battery, characterized in that: Includes the following steps: (1) The negative electrode material is homogenized, coated, dried, rolled and slit. The negative electrode material is composed of hard carbon, conductive carbon black, binder, dispersant and solvent. The solvent is water-based, the dispersant is CMC and the binder includes one or more of SBR and PAA. (2) The positive electrode material is homogenized, coated, dried, rolled and slit. The positive electrode material is composed of sodium nickel cobalt manganese oxide, conductive carbon black, binder, dispersant and solvent. The solvent is NMP solvent, the dispersant is CMC and the binder includes one or more of PVDF and SBR. (3) The electrode sheets obtained in steps (1) and (2) are subjected to electrode tab welding, winding, and steel shell welding; (4) The bare battery cell obtained in step (3) is baked, injected with electrolyte, and left to stand. The electrolyte is composed of sodium hexafluorophosphate and additives, wherein the additives include one or more of ethylamine, methylamine, and ethylamine. (5) The cells obtained in step (4) are formed, aged, tested for capacity and performance.

2. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: One or more organic acids, such as acetic acid, oxalic acid, and acetic acid, were added to the homogenized material in step (2).

3. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: in In the negative or positive electrode material, the proportion of hard carbon or sodium nickel cobalt manganese oxide is 90-95%, conductive carbon black is 1.5-4%, dispersant is 1.5-3%, and binder is 1.5-3%.

4. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: In step (3), the tab welding is full tab laser welding, the winding is automatic correction winding, and the diaphragm used is single-sided ceramic PP or PET.

5. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: The surface density of the coating on one side in step (1) is 40-55 g / m². 2 The surface density of the coating on one side in step (2) is 100-150 g / m². 2 .

6. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: The drying temperature in steps (1), (2), and (4) is between 50 and 95°C, and the baking or drying time is between 24 and 72 hours.

7. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: In step (1), the roller pressing pressure is between 3-7T, the roller pressing speed is between 5-20cm / s, and the resulting compacted density is between 0.6-1.0g / cm³. 3 The rolling pressure in step (2) is between 3-7T, the rolling speed is between 10-30cm / s, and the resulting compacted density is between 2.5-3.5g / cm³. 3 between.

8. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: In step (4), the moisture content of the bare battery cell after baking is between 100-500 ppm; the amount of additive added to the electrolyte in step (4) is between 1-5%; the water and oxygen content of the injected electrolyte in step (4) is required to be between 0-0.5 ppm for oxygen content and between 0-0.5 ppm for water content; the static activation temperature in step (4) is between 30-60℃ and the static time is between 24-72 hours.

9. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: In step (5), the chemical conversion is carried out at different rates of constant current and constant voltage to 60-80%; the aging temperature in step (5) is between 60-95℃ and the time is between 24-72 hours; in step (5), the constant current and constant voltage charge and discharge are carried out.

10. The method for manufacturing a cylindrical sodium-ion battery as described in claim 1, characterized in that: In steps (1)-(5), the temperature is between 15-25℃ and the humidity is between 1-10%.

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