Preparation method of high-rate charge-discharge composite titanium battery

Abstract

The invention discloses a preparation method of a high-rate charge-discharge composite titanium battery, and belongs to the technical field of battery preparation. The method comprises the following steps: S1, preparation of positive electrode slurry: uniformly mixing a solvent, a binder, a conductive agent and nickel cobalt lithium manganate, then adding conductive slurry, and stirring to obtain the positive electrode slurry; s2, preparation of negative electrode slurry: uniformly mixing a solvent, oxalic acid, a binder, a conductive agent and lithium titanate, then adding the conductive slurry, and stirring to obtain the negative electrode slurry; s3, coating a positive electrode: coating a carbon-coated aluminum foil with the positive electrode slurry, and compacting and slitting to obtain a positive plate; s4, coating a negative electrode: coating a carbon-coated aluminum foil with the negative electrode slurry, and compacting and slitting to obtain a negative plate; and S5, assembling: winding and welding the prepared positive and negative plates, then injecting liquid, and forming after the battery is well infiltrated to obtain the composite titanium battery. According to the preparation method of the high-rate charge-discharge composite titanium battery provided by the invention, the prepared composite titanium battery has ultrahigh-rate charge-discharge performance and long cycle life.

Description

Technical Field

[0001] The invention relates to the technical field of battery preparation, and in particular to a method for preparing a composite titanium battery with high-rate charge and discharge. Background Art

[0002] Faced with the increasingly serious energy crisis and environmental problems, the development of clean energy is an inevitable trend for sustainable development. Energy storage and conversion are the key to the development of clean energy and are increasingly valued by people. Various new energy batteries have emerged. Among the many batteries, lithium-ion batteries have become the most mature energy storage technology in recent years due to their many advantages such as high operating voltage, large capacity, good cycle performance and excellent environmental tolerance. Currently, lithium-ion batteries have been widely used in mobile communications, small electronic devices, energy storage power stations, electric vehicles, etc. In lithium-ion batteries, the negative electrode material is not only an indispensable part of the battery, but also has a vital impact on the performance of the battery. The research and development of various negative electrode materials for lithium-ion batteries has emerged in an endless stream. The research on negative electrode materials for lithium-ion batteries has shown a flourishing trend, with the emergence of silicon, graphite, graphene, oxides and Li4Ti5O 12 However, the current commercial applications are still dominated by graphite, and graphite as a negative electrode material has a low lithium insertion potential, and lithium dendrites may appear during the charge and discharge process, posing a risk of battery short circuit; at the same time, its gram capacity is small, and it is difficult to provide more lasting power; and its layered structure has poor stability, and it is easy to collapse after a long charge and discharge cycle, and the lithium ion diffusion rate is reduced, thus affecting its cycle stability and rate performance.

[0003] The existing lithium battery rate performance can only meet some normal market use, but it is temporarily unable to charge and discharge in special high-rate fields, or the high-rate charge and discharge affects the battery's own cycle life. In view of the above problems, the present invention aims to develop a method for preparing a composite titanium battery with high-rate charge and discharge, and apply it in the high-rate field. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a composite titanium battery with high-rate charge and discharge, so as to solve the problem that lithium batteries cannot be used in special ultra-high-rate fields.

[0005] To achieve the above object, the present invention provides a method for preparing a composite titanium battery with high rate charge and discharge, which specifically comprises the following steps:

[0006] S1. Preparation of positive electrode slurry: uniformly mix the solvent, binder, conductive agent and lithium nickel cobalt manganese oxide, then add the conductive slurry and stir to obtain the positive electrode slurry;

[0007] S2. Preparation of negative electrode slurry: uniformly mix the solvent, oxalic acid, binder, conductive agent and lithium titanate, then add the conductive slurry and stir to obtain negative electrode slurry;

[0008] S3, positive electrode coating: coating the positive electrode slurry on the carbon-coated aluminum foil, compacting and cutting to obtain the positive electrode sheet;

[0009] S4, negative electrode coating: coating the negative electrode slurry on the carbon-coated aluminum foil, compacting and cutting to obtain the negative electrode sheet;

[0010] S5. Assembly: Winding and welding the prepared positive and negative electrode sheets, and then injecting liquid. After the battery is well soaked, it is formed to obtain a composite titanium battery.

[0011] Preferably, in step S1, by mass percentage, 30%-40% of solvent, 4-5% of binder, 2-3% of conductive agent, 35-50% of lithium nickel cobalt manganese oxide and 15-20% of conductive paste are included.

[0012] Preferably, in step S2, by mass percentage, the mixture includes 50-70% of solvent, 0.1-1% of oxalic acid, 3-5% of binder, 0.5-1.5% of conductive agent, 20-30% of negative electrode main material and 0.2-1% of conductive paste.

[0013] Preferably, the solvent in step S1 is N-methylpyrrolidone; the binder is polyvinylidene fluoride; the conductive agent is carbon black; and the conductive paste is CNT carbon nanotubes.

[0014] Preferably, the solvent in step S2 is N-methylpyrrolidone; the binder is polyvinylidene fluoride; the conductive agent is carbon black; and the conductive paste is Li435.

[0015] Preferably, in step S5, the formation temperature is 80° C., the upper limit voltage is 2.8V, and the lower limit voltage is 1.5V.

[0016] Therefore, the present invention provides a method for preparing a composite titanium battery with high-rate charge and discharge. The prepared composite titanium battery has ultra-high-rate charge and discharge performance and a long cycle life, solving the problem that existing lithium batteries cannot meet the application requirements in special high-rate fields.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a rate charging curve diagram of a battery prepared according to an embodiment of the present invention;

[0019] Figure 2 The figure is a rate discharge curve diagram of a battery prepared according to an embodiment of the present invention;

[0020] Figure 3 The charge and discharge curve of the battery prepared in the embodiment of the present invention at -45°C / 0.3C low temperature;

[0021] Figure 4 It is a rate charging curve diagram of the battery in the control group of the present invention;

[0022] Figure 5 The figure is a rate discharge curve diagram of the battery in the control group of the present invention;

[0023] Figure 6 This is a charge and discharge curve of the battery in the control group of the present invention at -45°C / 0.3C low temperature;

[0024] Figure 7 The graph is a cycle curve of the battery prepared in the embodiment of the present invention and the battery of the control group. DETAILED DESCRIPTION

[0025] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example

[0027] This embodiment provides a method for preparing a composite titanium battery with high rate charge and discharge, which specifically includes the following steps:

[0028] S1. Preparation of positive electrode slurry: ① Add 33.8% N-methylpyrrolidone to a stirring tank; ② Add 4.8% polyvinylidene fluoride, divide it into three equal parts, and add it three times to make it fully dispersed; ③ Add 2.3% carbon black, add it twice; ④ Add 41.8% lithium nickel cobalt manganese oxide and stir it thoroughly; ⑤ Add 17.3% CNT carbon nanotubes; Stir the above materials thoroughly to obtain positive electrode slurry;

[0029] S2. Preparation of negative electrode slurry: ① Add 65.3% N-methylpyrrolidone into a stirring tank; ② Add 0.2% oxalic acid; ③ Add 3.6% polyvinylidene fluoride; ④ Add 1% carbon black; ⑤ Add 29.3% lithium titanate; ⑥ Add 0.6% Li435; Mix them evenly to obtain negative electrode slurry;

[0030] S3. Positive electrode coating: The positive electrode slurry was coated on a 16um carbon-coated aluminum foil at a speed of 5m / min. The coating surface density was 268±3.9g / m 2 ; compaction is 3.3g / cm 3 , and then baked for 36 hours to obtain the positive electrode sheet;

[0031] S4. Negative electrode coating: The negative electrode slurry was coated on a 16um carbon-coated aluminum foil at a speed of 3.5m / min. The coating surface density was 214±3.9g / m 2 , compacted to 1.9g / cm 3 , and then baked for 48 hours to obtain the negative electrode sheet;

[0032] S5. Assembly: Wind the prepared positive and negative electrode sheets, the thickness of the isolation film is 16um*157mm wide, the positive electrode length is 5850mm, and the negative electrode length is 5730mm. After winding, weld and inject liquid (the injection amount is 103-105g). After the battery is well infiltrated, form the battery, the formation temperature is 80℃, the upper limit voltage is 2.8V, and the lower limit voltage is 1.5V.

[0033] The battery prepared in this embodiment was tested at low temperature and rate, and the results are as follows: Figure 1-3 As shown, the existing battery was used as the control group for low temperature and rate tests, and the results are as follows Figure 4-6 shown.

[0034] Depend on Figure 1-2 and Figure 4-5 By comparison, the 10C charging capacity retention rate of the control group is 97.0%, and the discharge capacity retention rate is 95.8%, while the 30C charging capacity retention rate of the experimental group is 84.7%, and the discharge capacity retention rate is 72.6%, which is significantly better than the control group.

[0035] Depend on Figure 3 and Figure 6 By comparison, at the same temperature and charge rate (-45℃ / 0.3C), the charge capacity retention rate of the control group was 67.37%, which was 21.35% lower than that of the experimental group (88.72%); the discharge capacity retention rate was 59.89%, which was 34.81% lower than that of the experimental group (94.7%).

[0036] The battery prepared in this embodiment was tested for cycle performance, and the existing battery was used as a control group. The cycle curve is shown in the following figure: Figure 7 shown.

[0037] Depend on Figure 7 It can be seen that in the 2C / 2C room temperature cycle process, the capacity retention rate of the experimental group after 20,000 cycles is 90.05%, and the capacity retention rate of the control group after 10,000 cycles is 81.21%. The results show that the cycle life of the experimental group is significantly better than that of the control group.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a composite titanium battery with high rate charge and discharge, characterized in that: The specific steps include: S1. Preparation of positive electrode slurry: uniformly mix the solvent, binder, conductive agent and lithium nickel cobalt manganese oxide, then add the conductive slurry and stir to obtain the positive electrode slurry; S2. Preparation of negative electrode slurry: uniformly mix the solvent, oxalic acid, binder, conductive agent and lithium titanate, then add the conductive slurry and stir to obtain negative electrode slurry; S3, positive electrode coating: coating the positive electrode slurry on the carbon-coated aluminum foil, compacting and cutting to obtain the positive electrode sheet; S4, negative electrode coating: coating the negative electrode slurry on the carbon-coated aluminum foil, compacting and cutting to obtain the negative electrode sheet; S5. Assembly: Winding and welding the prepared positive and negative electrode sheets, and then injecting liquid. After the battery is well soaked, it is formed to obtain a composite titanium battery.

2. The method for preparing a high-rate charge-discharge composite titanium battery according to claim 1, characterized in that: In the step S1, by mass percentage, 30%-40% of solvent, 4-5% of binder, 2-3% of conductive agent, 35-50% of lithium nickel cobalt manganese oxide and 15-20% of conductive paste are included.

3. The method for preparing a high-rate charge-discharge composite titanium battery according to claim 1, characterized in that: In the step S2, by mass percentage, the mixture includes 50-70% of solvent, 0.1-1% of oxalic acid, 3-5% of binder, 0.5-1.5% of conductive agent, 20-30% of negative electrode main material and 0.2-1% of conductive paste.

4. The method for preparing a composite titanium battery with high rate charge and discharge according to claim 1, characterized in that: The solvent in step S1 is N-methylpyrrolidone; the binder is polyvinylidene fluoride; the conductive agent is carbon black; and the conductive paste is CNT carbon nanotubes.

5. The method for preparing a high-rate charge-discharge composite titanium battery according to claim 1, characterized in that: The solvent in step S2 is N-methylpyrrolidone; the binder is polyvinylidene fluoride; the conductive agent is carbon black; and the conductive paste is Li435.

6. The method for preparing a high-rate charge-discharge composite titanium battery according to claim 1, characterized in that: In step S5, the formation temperature is 80° C., the upper limit voltage is 2.8V, and the lower limit voltage is 1.5V.

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