In-situ carbon-coated vanadium oxide positive electrode sheet coating device and method for battery pack

Abstract

The invention relates to the technical field of positive electrode sheet coating, and in particular to an in-situ carbon-coated vanadium oxide positive electrode sheet coating device for a battery pack. The device comprises a support frame, a driving member arranged on the support frame, and a turntable driven by the driving member, wherein a plurality of stirring barrels are arranged on the turntable, a top cover is arranged on the upper end of the stirring barrel, a stirring assembly is arranged on the top cover, a magnetic stirring assembly is arranged in the stirring barrel, a support plate is arranged at the lower end of the turntable, a coater is arranged at the lower end of the support plate, a mixed slurry is stirred by stirring blades, a magnet a and a magnet b adsorb and release a stirring ball by continuous multiple switching on and off, and drive the stirring ball to move irregularly to stir the slurry; the problem that the uneven mixing of the used slurry leads to poor coating effect of the titanium foil, the slurry attached to the titanium foil is easy to fall off, the adhesion is poor, and thus the failure rate of the positive electrode sheet is increased is solved.

Description

Technical Field

[0001] The invention relates to the technical field of positive electrode sheet coating, in particular to an in-situ carbon-coated vanadium oxide positive electrode sheet coating device and method for a battery pack. Background Art

[0002] Among many positive electrode materials, vanadium oxide has attracted much attention due to its advantages such as large theoretical specific capacity, diverse crystal structure, abundant resources and low cost. However, pure phase vanadium oxide materials have problems such as poor cycle stability and complex performance modification process. Therefore, using a simple and efficient modification method to prepare a stable and high-capacity vanadium oxide positive electrode material is one of the problems to be solved. A Chinese invention patent with application announcement number CN112718377B discloses a coating machine for lithium battery production, including a box, a support column and a feeding component. By starting a rotating motor to drive the gear set to move, the material inside the coating tube adheres to the surface of the positive electrode sheet or the negative electrode sheet, and the positive electrode sheet or the negative electrode sheet that has been turned by the pulley is further dried. Finally, Simply place the dried positive or negative electrode sheets on the outer surface of the winding tube, which significantly reduces the time required for production and improves the quality of the product. A Chinese invention patent with application announcement number CN118287340A discloses a feeding device for coating lithium battery positive electrode sheet slurry, including a transfer tank, a liquid outlet pipe, a liquid pump, a base, a liquid inlet pipe and a processing tank. When the connecting block descends, it presses the lifting plate, causing the lifting plate to move downward through the sliders on both sides, driving the bottom rod to push the sealing rubber downward, and at the same time squeezing the slurry downward, so that the slurry can be discharged from the discharge hole to the coating machine head at a uniform speed to avoid slurry accumulation.

[0003] However, the inventors found that the uneven mixing of the slurry used in the actual production process resulted in poor coating effect on the titanium foil, and the slurry attached to the titanium foil was easy to fall off and the adhesion was poor, which led to an increase in the failure rate of the positive electrode sheets. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art. The mixed slurry is stirred by a stirring blade, and the magnets a and b adsorb and release the stirring ball by repeatedly switching on and off the magnetism, thereby driving the stirring ball to move irregularly to stir the slurry, thereby solving the problem that the uneven mixing of the slurry used leads to a poor coating effect of the titanium foil, the slurry attached to the titanium foil is easy to fall off, the adhesion is poor, and thus the failure rate of the positive electrode sheet is increased.

[0005] In view of the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] An in-situ carbon-coated vanadium oxide positive electrode sheet coating device for a battery pack comprises a support frame, a driving member arranged on the support frame and a turntable driven by the driving member, wherein a plurality of stirring barrels are arranged on the turntable, a top cover is arranged on the upper end of the stirring barrel, a stirring assembly is arranged on the top cover, a magnetic stirring assembly is arranged in the stirring barrel, a support plate is arranged at the lower end of the turntable, a coater is arranged at the lower end of the support plate, materials in the stirring barrel are stirred and mixed by the stirring assembly, and materials at the edge of the stirring barrel are fully stirred by the magnetic stirring assembly.

[0007] Preferably, the magnetic stirring assembly comprises a plurality of magnets a arranged on the side wall of the stirring barrel, a plurality of magnets b arranged on the top cover and a plurality of stirring balls arranged in the stirring barrel.

[0008] As a preference, the stirring ball is provided with a plurality of protrusions, the magnet a and the magnet b are both electromagnets with strong magnetic properties, and the magnet a and the magnet b can be switched on and off continuously for multiple times.

[0009] Preferably, the stirring assembly includes a fixing frame arranged on the top cover, a motor arranged in the fixing frame, and a stirring rod driven by the motor.

[0010] As a preference, the stirring rod is provided with a plurality of stirring blades, and the stirring blades are provided in at least two groups up and down.

[0011] As a preference, a discharge port is provided at the lower end of the mixing barrel, and a feed pipe is provided on the top cover.

[0012] As a preference, a feed discharge port is provided on the support plate.

[0013] As another preferred embodiment, the coating machine is provided with a material receiving pipe, and the material receiving pipe is connected to the material discharge port.

[0014] In addition, the present invention also provides a method for coating a positive electrode sheet of vanadium oxide in situ carbon for a battery pack, comprising the following steps:

[0015] a. Preparation process of positive electrode material, 0.5g of vanadium pentoxide is dissolved in a glass beaker filled with 20mL of deionized water under the action of magnetic stirring, 10mL of ethylene glycol and a certain amount of glucose are added to the obtained orange-yellow suspension according to the mass ratio of 10%, 20%, 30% and 50%, and stirring is continued for 20-30min, and the mixed solution is continuously heated at 180°C for 6h by a 50mL high-pressure reactor, and after it is naturally cooled to room temperature, it is centrifuged and washed three times with deionized water and anhydrous ethanol respectively, and the precipitate is collected and vacuum dried at 80°C for 12h to obtain vanadium dioxide with different carbon coating amounts;

[0016] b. In the feeding process, appropriate amounts of active materials, conductive carbon and polyvinylidene fluoride are weighed manually in a mass ratio of 7:2:1 and added into the feeding pipe, and an appropriate amount of N-methylpyrrolidone solution is added. The mixed slurry is stirred by the stirring blades. Magnets a and magnets b adsorb and release the stirring ball by continuous switching on and off, driving the stirring ball to move irregularly to stir the slurry. The stirring barrel is driven by the turntable to rotate to the discharge port, and the evenly mixed slurry falls into the receiving pipe and enters the coating machine;

[0017] c. Coating and drying process: the slurry is evenly coated on the titanium foil by a coating machine, and the coated electrode sheet is vacuum dried at 80°C for 12h;

[0018] d. Rolling and cutting process: the dried electrode sheets are rolled by a tablet press and cut into suitable sizes by a cutter.

[0019] Beneficial effects of the present invention:

[0020] 1. In the present invention, the mixed slurry is stirred by a stirring blade, and the magnets a and b adsorb and release the stirring ball by switching on and off the magnetism for multiple times continuously, driving the stirring ball to move irregularly to stir the slurry, which is beneficial to uniformly mix the slurry, improve the adhesion of the slurry, and thus improve the product qualification rate.

[0021] 2. In the present invention, readily available glucose is used as the carbon source, and a "one-step method" is used to successfully prepare carbon-coated vanadium dioxide with a tunnel structure. By comparing the electrochemical properties under different carbon coating amounts, the optimal carbon coating amount is obtained, which provides convenience for subsequent performance research. 30% carbon-coated vanadium dioxide has a high electrochemical performance at 0.5A g -1 At a current density of 2.5, the first discharge capacity is 268 mAh g -1 After 100 cycles, the discharge capacity is still 259 mAh g -1 , the battery exhibits good cycling stability.

[0022] In summary, the equipment has the advantages of improving the adhesion of the slurry and increasing the product qualification rate, and is particularly suitable for the field of positive electrode sheet coating technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of an in-situ carbon-coated vanadium oxide positive electrode coating device for a battery pack;

[0025] Figure 2 It is a structural schematic diagram of a positive electrode sheet coating device;

[0026] Figure 3 It is a cross-sectional schematic diagram of a mixing barrel;

[0027] Figure 4 is a cross-sectional schematic diagram of a stirring rod;

[0028] Figure 5 is a structural schematic diagram of a support plate;

[0029] Figure 6 A working state diagram of the in-situ carbon-coated vanadium oxide positive electrode coating device for a battery pack;

[0030] Figure 7 This is a working state diagram of the positive electrode coating device;

[0031] Figure 8 is the XRD pattern of the synthesized sample;

[0032] Fig. 9 The SEM and element distribution diagram of 30% carbon-coated vanadium dioxide;

[0033] Fig.10 Comparison of electrochemical performance under different carbon coating amounts.

[0034] 1. Support frame; 2. Driving part; 3. Turntable; 4. Stirring barrel; 5. Stirring assembly; 6. Magnetic stirring assembly; 7. Support plate; 8. Coater; 41. Top cover; 42. Discharge port; 43. Feed pipe; 51. Fixed frame; 52. Motor; 53. Stirring rod; 54. Stirring blade; 61. Magnet a; 62. Magnet b; 63. Stirring ball; 64. Bump; 71. Discharge port; 81. Feed pipe. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings.

[0036] Embodiment 1

[0037] like Figures 1 to 7As shown, an in-situ carbon-coated vanadium oxide positive electrode sheet coating device for a battery pack comprises a support frame 1, a driving member 2 arranged on the support frame 1, and a turntable 3 driven by the driving member 2, wherein a plurality of stirring barrels 4 are arranged on the turntable 3, a top cover 41 is arranged on the upper end of the stirring barrel 4, a stirring assembly 5 is arranged on the top cover 41, a magnetic stirring assembly 6 is arranged in the stirring barrel 4, a support plate 7 is arranged at the lower end of the turntable 3, a coater 8 is arranged at the lower end of the support plate 7, the material in the stirring barrel 4 is stirred and mixed by the stirring assembly 5, and the material at the edge of the stirring barrel 4 is fully stirred by the magnetic stirring assembly 6.

[0038] It is worth mentioning here that the mixed slurry is stirred by the stirring blade 54, and the magnet a61 and the magnet b62 adsorb and release the stirring ball 63 by continuously switching the magnet on and off, thereby driving the stirring ball 63 to move irregularly to stir the slurry, which is beneficial to uniformly mix the slurry, improve the adhesion of the slurry, and thus improve the product qualification rate.

[0039] like Figure 3 , Figure 4 As shown, the magnetic stirring assembly 6 includes a plurality of magnets a61 arranged on the side wall of the stirring barrel 4 , a plurality of magnets b62 arranged on the top cover 41 , and a plurality of stirring balls 63 arranged in the stirring barrel 4 .

[0040] In this example, the magnet a61 and the magnet b62 adsorb and release the stirring ball 63 by switching the magnets on and off repeatedly, thereby driving the stirring ball 63 to move irregularly to stir the slurry.

[0041] like Figure 3 As shown, a plurality of protrusions 64 are provided on the stirring ball 63, and the magnet a61 and the magnet b62 are both electromagnets with strong magnetic properties, and the magnet a61 and the magnet b62 can be switched on and off continuously for multiple times.

[0042] In this example, by providing the protrusion 64, the stirring ball 63 can bring up the slurry on the edge of the barrel wall of the stirring barrel 4, so that the slurry is mixed more evenly.

[0043] like Figure 3 As shown, the stirring assembly 5 includes a fixing frame 51 disposed on the top cover 41 , a motor 52 disposed in the fixing frame 51 , and a stirring rod 53 driven by the motor 52 .

[0044] like Figure 3 As shown, a plurality of stirring blades 54 are disposed on the stirring rod 53, and at least two groups of stirring blades 54 are disposed in the upper and lower parts.

[0045] In this embodiment, at least two groups of stirring blades 54 are provided in the upper and lower parts to make the slurry mixed more evenly.

[0046] like Figure 2 , Figure 3 As shown, a discharge port 42 is provided at the lower end of the mixing barrel 4 , and a feed pipe 43 is provided on the top cover 41 .

[0047] like Figure 5 As shown, a feed opening 71 is provided on the support plate 7 .

[0048] In this example, the upper surface of the support plate 7 is tightly fitted to the lower surface of the mixing barrel 4 .

[0049] like Figure 2 As shown, the coating machine 8 is provided with a material receiving pipe 81 , and the material receiving pipe 81 is connected to the material discharge port 71 .

[0050] Embodiment 2

[0051] like Figures 1 to 10 As shown, a method for coating a positive electrode sheet of vanadium oxide with in-situ carbon coating for a battery pack, using the positive electrode sheet coating device of vanadium oxide with in-situ carbon coating for a battery pack, comprises the following steps:

[0052] a. Preparation process of positive electrode materials: 0.5 g of vanadium pentoxide is dissolved in a glass beaker containing 20 mL of deionized water under magnetic stirring, 10 mL of ethylene glycol and a certain amount of glucose (10%, 20%, 30% and 50% by mass) are added to the obtained orange-yellow suspension, and stirring is continued for 20-30 min. The mixed solution is continuously heated at 180°C for 6 h in a 50 mL high-pressure reactor. After it is naturally cooled to room temperature, it is centrifuged and washed three times with deionized water and anhydrous ethanol respectively, and the precipitate is collected and vacuum dried at 80°C for 12 h to obtain vanadium dioxide with different carbon coating amounts;

[0053] b. Loading process, manually weigh appropriate amounts of active material, conductive carbon and polyvinylidene fluoride in a mass ratio of 7:2:1 and add them into the feed pipe 43, and add an appropriate amount of N-methylpyrrolidone solution, stir the mixed slurry through the stirring blade 54, and the magnet a61 and the magnet b62 adsorb and release the stirring ball 63 by continuous switching on and off, driving the stirring ball 63 to move irregularly to stir the slurry, and the stirring barrel 4 is driven by the turntable 3 to rotate to the discharge port 71, and the evenly mixed slurry falls into the receiving pipe 81 and enters the coating machine 8;

[0054] c. coating and drying process, the slurry is evenly coated on the titanium foil by a coater 8, and the coated electrode sheet is vacuum dried at 80°C for 12h;

[0055] d. Rolling and cutting process: the dried electrode sheets are rolled by a tablet press and cut into suitable sizes by a cutter.

[0056] It is worth mentioning that the carbon-coated vanadium dioxide with a tunnel structure was successfully prepared by a one-step method using readily available glucose as the carbon source. By comparing the electrochemical properties under different carbon coating amounts, the optimal carbon coating amount was obtained, which facilitated the subsequent performance research. The 30% carbon-coated vanadium dioxide had a good electrochemical performance at 0.5A g -1 At a current density of 2.5, the first discharge capacity is 268 mAh g -1 After 100 cycles, the discharge capacity is still 259 mAh g -1 , the battery exhibits good cycling stability.

[0057] The working process is as follows:

[0058] Under the action of magnetic stirring, 0.5 g of vanadium pentoxide was dissolved in a glass beaker filled with 20 mL of deionized water, 10 mL of ethylene glycol and a certain amount of glucose (10%, 20%, 30% and 50% by mass) were added to the obtained orange-yellow suspension, and stirring was continued for 20-30 min. The mixed solution was heated continuously at 180° C. for 6 h in a 50 mL high-pressure reactor, and after it was naturally cooled to room temperature, it was centrifuged and washed three times with deionized water and anhydrous ethanol respectively, and the precipitate was collected and vacuum dried at 80° C. for 12 h to obtain vanadium dioxide with different carbon coating amounts;

[0059] An appropriate amount of active material, conductive carbon and polyvinylidene fluoride are weighed manually in a mass ratio of 7:2:1 and added into the feed pipe 43, and an appropriate amount of N-methylpyrrolidone solution is added, and the stirring rod 53 is driven to rotate by the motor 52, thereby driving the stirring blade 54 to rotate, and the mixed slurry is stirred by the stirring blade 54, and the magnet a61 and the magnet b62 adsorb and release the stirring ball 63 by repeatedly switching on and off the magnet, driving the stirring ball 63 to move irregularly to stir the slurry, and when the stirring ball 63 falls after the magnet is disconnected, the stirring blade 54 drives it to stir the slurry, and when the magnet is turned on, the stirring ball 63 is sucked up and moves irregularly to stir the slurry, and the turntable 3 is driven to rotate by the driving member 2, and the stirring barrel 4 is driven to rotate to the discharge port 71 by the turntable 3, and the evenly mixed slurry falls into the receiving pipe 81 and enters the coating machine 8;

[0060] The slurry is evenly coated on the titanium foil by a coating machine 8, and the coated electrode sheet is vacuum dried at 80° C. for 12 hours, rolled by a tablet press, and cut into a suitable size by a sheet cutter.

[0061] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art under the technical guidance of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An in-situ carbon-coated vanadium oxide positive electrode coating device for a battery pack, comprising a support frame (1), a driving member (2) arranged on the support frame (1), and a rotating disk (3) driven by the driving member (2), characterized in that: A plurality of stirring barrels (4) are arranged on the turntable (3); a top cover (41) is arranged on the upper end of the stirring barrel (4); a stirring assembly (5) is arranged on the top cover (41); a magnetic stirring assembly (6) is arranged in the stirring barrel (4); the magnetic stirring assembly (6) comprises a plurality of magnets a (61) arranged on the side wall of the stirring barrel (4); a plurality of magnets b (62) arranged on the top cover (41); and a plurality of stirring balls (63) arranged in the stirring barrel (4); a plurality of protrusions (64) are arranged on the stirring balls (63); the magnets a (61) and the magnets b (62) are arranged on the top cover (41); b (62) all use electromagnets with strong magnetic properties, and the magnets a (61) and b (62) can be switched on and off for multiple times in succession. The magnets a (61) and b (62) adsorb and release the stirring ball (63) by switching on and off for multiple times in succession, thereby driving the stirring ball (63) to move irregularly to stir the slurry. A support plate (7) is provided at the lower end of the turntable (3), and a coating machine (8) is provided at the lower end of the support plate (7). The material in the stirring barrel (4) is stirred and mixed by the stirring component (5), and the material at the edge of the stirring barrel (4) is fully stirred by the magnetic stirring component (6).

2. The in-situ carbon-coated vanadium oxide positive electrode sheet coating device for battery pack according to claim 1, characterized in that: The stirring assembly (5) comprises a fixing frame (51) arranged on the top cover (41), a motor (52) arranged in the fixing frame (51), and a stirring rod (53) driven by the motor (52).

3. The in-situ carbon-coated vanadium oxide positive electrode sheet coating device for battery pack according to claim 2, characterized in that: The stirring rod (53) is provided with a plurality of stirring blades (54), and the stirring blades (54) are provided in at least two groups at the top and the bottom.

4. The in-situ carbon-coated vanadium oxide positive electrode sheet coating device for battery pack according to claim 1, characterized in that: The lower end of the mixing barrel (4) is provided with a discharge port (42), and the top cover (41) is provided with a feed pipe (43).

5. The in-situ carbon-coated vanadium oxide positive electrode sheet coating device for battery pack according to claim 1, characterized in that: The support plate (7) is provided with a material discharge opening (71).

6. The in-situ carbon-coated vanadium oxide positive electrode sheet coating device for battery pack according to claim 1, characterized in that: The coating machine (8) is provided with a material receiving pipe (81), and the material receiving pipe (81) is connected to the material discharge port (71).

7. A method for coating a positive electrode sheet of vanadium oxide in situ carbon coating for a battery pack, using the positive electrode sheet coating device of vanadium oxide in situ carbon coating for a battery pack according to claim 1, comprising the following steps: a. Preparation process of positive electrode materials: 0.5g of vanadium pentoxide is dissolved in a glass beaker containing 20mL of deionized water under magnetic stirring, 10mL of ethylene glycol and a certain amount of glucose are added to the obtained orange-yellow suspension, and stirring is continued for 20-30min. The mixed solution is continuously heated at 180°C for 6h in a 50mL high-pressure reactor. After it is naturally cooled to room temperature, it is centrifuged and washed three times with deionized water and anhydrous ethanol respectively, the precipitate is collected, and vacuum dried at 80°C for 12h to obtain vanadium dioxide with different carbon coating amounts; b. Loading process: appropriate amounts of active materials are weighed manually according to a mass ratio of 7:2:1 , conductive carbon and polyvinylidene fluoride are added into the feed pipe (43), and an appropriate amount of N-methylpyrrolidone solution is added, and the mixed slurry is stirred by the stirring blade (54), and the magnet a (61) and the magnet b (62) adsorb and release the stirring ball (63) by repeatedly switching the magnets on and off, driving the stirring ball (63) to move irregularly to stir the slurry, and the stirring barrel (4) is driven by the turntable (3) to rotate to the discharge port (71), and the evenly mixed slurry falls into the receiving pipe (81) and enters the coating machine (8); c. coating and drying process, the slurry is evenly coated on the titanium foil by the coating machine (8), and the coated electrode sheet is vacuum dried at 80°C for 12 hours; d. Rolling and cutting process: the dried electrode sheets are rolled by a tablet press and cut into suitable sizes by a sheet cutter.

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