Laboratory rolling device for reducing rebound of pole piece

Abstract

The utility model discloses a laboratory rolling device for reducing pole piece rebound, which relates to the technical field of lithium ion battery pole piece processing, and comprises a bottom frame and a driving component, one side of the bottom frame is rotatably connected with two small compaction rollers, and a large compaction roller is rotatably connected between two middle cross beams of the bottom frame. First supporting frames and second supporting frames are installed on the two sides of the bottom frame correspondingly, infrared heating plates are symmetrically installed between the two first supporting frames, discharging supports are installed at the upper ends of the two second supporting frames, an installation table is installed on the bottom frame, and the driving assembly is installed on the installation table and drives the small compaction roller and the large compaction roller to rotate. According to the utility model, the two infrared heating plates are firstly used for heating the two sides of the pole piece respectively, and then the small compaction roller is used for rolling the pole piece in a small rolling reduction, and the rolling reduction is 40%; and finally, a large compaction roller is used for carrying out large rolling reduction on the pole piece, the rolling reduction is 60%, rebound of the pole piece after rolling can be effectively reduced, and the thickness of the pole piece can keep good consistency.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion battery pole piece processing, in particular to a laboratory rolling device for reducing pole piece rebound. Background Art

[0002] The battery is composed of positive and negative electrodes, electrolyte, separator and shell, and the positive and negative plates play a very important role in the battery. After the coating and drying of the plate, the coating is thick and there may be burrs on the surface that can pierce the separator and cause a short circuit in the battery; at the same time, the contact between the active substances on the surface and the current collector is not tight, resulting in weak adhesion of the plate, and the battery plate will lose powder during the cycle. Therefore, it is necessary to roll the plate to ensure that the surface of the plate is smooth and flat to prevent the burrs of the plate from piercing the separator; to enhance the bonding strength between the active substance and the foil to prevent the active substance from peeling off during the immersion of the electrolyte and the use of the battery.

[0003] The compaction density of the pole piece needs to be controlled after rolling. The compaction density of the pole piece has a great influence on the electrochemical performance of the battery. Within a certain range, as the compaction density increases, the distance between the active material particles decreases, the contact area increases, and it is beneficial to ion conduction. In macroscopic terms, it is manifested as a decrease in the internal resistance of the battery. However, if the compaction density of the pole piece is too large, the contact between the active material particles is too close, and the electronic conductivity increases. However, the lithium ion channels are reduced or blocked, which is not conducive to the use of capacity. During charging and discharging, polarization increases, voltage decreases, and capacity decreases. When the compaction density is too small, the distance between the particles is large, the lithium ion movement channel is unobstructed, and the electrolyte has a strong liquid absorption capacity, which is conducive to the movement of lithium ions inside the battery. However, since the contact between the particles is not close enough, it is not conducive to the conduction of electrons. During discharge, it is easy to cause increased polarization.

[0004] At present, the laboratory usually uses a manual spiral pressurized pole piece rolling mill, which has no additional pressurizing device and only rolls the pole piece once at room temperature. Therefore, the actual pressure is generally small, the compaction density of the rolled pole piece is limited, and there is a large deformation resistance. The pole piece rebounds greatly after rolling, and the consistency of the pole piece thickness is poor. Utility Model Content

[0005] The utility model aims to provide a laboratory rolling device for reducing the rebound of pole pieces, so as to solve the above-mentioned multiple defects caused by the prior art.

[0006] A laboratory rolling device for reducing the rebound of electrode pieces comprises a base frame and a driving assembly, wherein two small horizontally arranged compacting rollers are rotatably connected between two upright posts on one side of the base frame, and the base frame is located between two middle cross beams and is rotatably connected with two large horizontally arranged compacting rollers, a first supporting frame is installed on one side of the two upright posts of the base frame located on the small compacting roller side, and a second supporting frame is installed on one side of the two upright posts of the base frame away from the small compacting roller side, an infrared heating plate for heating the electrode pieces is symmetrically installed between the two first supporting frames, a discharging bracket is installed on the upper ends of the two second supporting frames, a mounting platform is installed on the base frame, the driving assembly is installed on the mounting platform, and the driving assembly drives the small compacting roller and the large compacting roller to rotate.

[0007] Preferably, the driving assembly includes a motor and a reducer installed on a mounting platform, the output end of the motor is connected to the input end of the reducer, the output end of the reducer is connected to the rotating shaft of the large compaction roller, and the rotating shafts of the large compaction roller and the small compaction roller are respectively installed with an active synchronous wheel and a driven synchronous wheel, and the outer sides of the active synchronous wheel and the driven synchronous wheel are sleeved with a synchronous belt.

[0008] Preferably, a cover covering the driving assembly is installed on the base frame.

[0009] Preferably, guide rollers are rotatably connected between the two first support frames and the two second support frames.

[0010] Preferably, a plurality of supporting legs are installed on the bottom side of the base frame.

[0011] The advantages of the utility model are as follows: the utility model first heats the two sides of the pole piece respectively through two infrared heating plates, and then uses a small compaction roller to roll the pole piece with a small reduction amount of 40%; finally, uses a large compaction roller to roll the pole piece with a large reduction amount of 60%. After rolling, the pole piece can effectively reduce rebound, and the thickness of the pole piece can maintain good consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0013] Figure 2 , Figure 3 It is a schematic diagram of the structure of the utility model from different viewing angles without the pole piece installed.

[0014] Figure 4 It is a schematic diagram of the structure inside the cover of the utility model.

[0015] Figure 5 This is a curve chart of the measured data of the equally spaced thickness on the negative electrode sheet after rolling with different devices.

[0016] Figure 6This is a bar chart of the rebound thickness of the anode electrode after rolling for different times.

[0017] Figure 7 This is a curve chart of the measured data of the equally spaced thickness on the positive electrode sheet after rolling with different devices.

[0018] Figure 8 This is a bar chart of the rebound thickness of the cathode electrode after rolling for different times.

[0019] Among them: 1-base frame; 2-drive assembly; 3-small compacting roller; 4-large compacting roller; 5-first support frame; 6-second support frame; 7-pole piece; 8-infrared heating plate; 9-discharging bracket; 10-mounting table; 11-motor; 12-reducer; 13-active synchronous wheel; 14-driven synchronous wheel; 15-synchronous belt; 16-cover; 17-guide roller; 18-support leg. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0021] like Figures 1 to 8 As shown, a laboratory rolling device for reducing the rebound of electrode pieces comprises a base frame 1 and a driving assembly 2, two small horizontally arranged compacting rollers 3 are rotatably connected between two columns on one side of the base frame 1, and two large horizontally arranged compacting rollers 4 are rotatably connected to the base frame 1 between two middle beams, a first support frame 5 is installed on one side of the two columns of the base frame 1 located on the side of the small compacting roller 3, a second support frame 6 is installed on one side of the two columns of the base frame 1 away from the side of the small compacting roller 3, an infrared heating plate 8 for heating the electrode piece 7 is symmetrically installed between the two first support frames 5, and a discharging bracket 9 is installed on the upper ends of the two second support frames 6, a mounting platform 10 is installed on the base frame 1, and the driving assembly 2 is installed on the mounting platform 10, and the driving assembly 2 drives the small compacting roller 3 and the large compacting roller 4 to rotate. The infrared heating plate 8 is electrically connected to the on-site power supply, and the infrared heating plate 8 adjusts the heating temperature through an independent control unit installed on the chassis 1. The infrared heating plate 8 is used to adjust the temperature of the battery pole piece 7 during rolling. The heated pole piece 7 can reduce the deformation resistance and plastic deformation of the pole piece 7 during the rolling process. The small compaction roller 3 has a roller diameter of 4 cm, and the pole piece 7 is rolled with a small amount of pressure. The other pair is a large compaction roller 4 with a roller diameter of 12 cm, which is rolled with a large amount of pressure. The small compaction roller 3 has a faster rotation speed, and the large compaction roller 4 has a slower speed. The linear speeds of the two pairs of compaction rollers will remain consistent. The rollers are loaded with pressure on the pole piece 7 through the roller gap. By setting up double rollers, the rebound of the pole piece 7 can be reduced and the thickness consistency of the pole piece after rolling is high.

[0022] In this embodiment, the driving assembly 2 includes a motor 11 and a reducer 12 mounted on a mounting platform 10, the output end of the motor 11 is connected to the input end of the reducer 12, the output end of the reducer 12 is connected to the rotating shaft of the large compaction roller 4, and the rotating shafts of the large compaction roller 4 and the small compaction roller 3 are respectively mounted with a driving synchronous wheel 13 and a driven synchronous wheel 14, and the outer sides of the driving synchronous wheel 13 and the driven synchronous wheel 14 are sleeved with a synchronous belt 15. The ratio of the diameters of the driving synchronous wheel 13 and the driven synchronous wheel 14 is the same as the ratio of the diameters of the large compaction roller 4 and the small compaction roller 3, and the driving synchronous wheel 13 and the driven synchronous wheel 14 are connected by a synchronous belt 15, so as to ensure that the linear speeds of the driving synchronous wheel 13 and the driven synchronous wheel 14 are the same, thereby ensuring that the linear speeds of the large compaction roller 4 and the small compaction roller 3 are the same.

[0023] In this embodiment, a cover 16 for covering the driving assembly 2 is installed on the base frame 1. The cover 16 plays the role of dust prevention and protection of the driving assembly 2.

[0024] In this embodiment, guide rollers 17 are rotatably connected between the two first support frames 5 and the two second support frames 6 .

[0025] In this embodiment, a plurality of support legs 18 are installed on the bottom side of the base frame 1. The support legs 18 are installed on the base frame 1 through nuts, and the height of the support legs 18 can be adjusted through the nuts, so as to facilitate the leveling operation of the base frame 1.

[0026] The specific experimental steps are as follows:

[0027] Prepare single-sided pole pieces, the slurry ratio is respectively, negative electrode powder: SP: CMC: binder = 92:3:3:2, positive electrode powder: SP: PVDF = 96.5:1.5:2, and after coating and drying, the pole piece 7 to be tested is cut into a rectangular size of about 5cm×10cm. Use different roller presses to roll the pole pieces to prepare pole pieces 7 with different compaction densities, use a micrometer to measure the equal spacing thickness of the pole piece 7 after rolling and the thickness of the rebound after different shelf time, and draw a curve graph.

[0028] Embodiment 1:

[0029] Prepare the negative electrode slurry with the above ratio, and the coating height is 400μm. After coating and drying, cut the electrode to be tested into rectangular sizes of about 5cm×10cm, which are recorded as A1, B1, C1 and A2, B2, C2 respectively. A1, B1, and C1 are rolled into electrode sheets with compaction densities of 1.3g / cm3, 1.45g / cm3, and 1.6g / cm3 respectively using a single roller machine. At the same time, use this device to roll A2, B2, and C2 into electrode sheets with compaction densities of 1.3g / cm3, 1.45g / cm3, and 1.6g / cm3 respectively. Measure the equally spaced thickness of the electrode sheets after rolling and the rebound thickness after 0.5h, 1h, and 2h (as shown in Tables 1 and 2), and draw a curve graph (as shown in the attached figure). Figure 5 shown).

[0030] Table 1: Statistics of anode pole piece thickness at different measuring points after rolling

[0031]

[0032]

[0033] Table 2: Statistics of the rebound thickness of anode pole pieces at different times after rolling

[0034]

[0035]

[0036] Attached Figure 5 The graph is a data curve of the thickness measurement of the negative electrode sheet 7 after rolling by different devices. It can be seen from the figure that under three different compaction densities, the thickness uniformity of the electrode sheet 7 rolled by the present device is better than that of the electrode sheet rolled by a single roller, and the thickness difference at different points is small, and the standard deviation is within 0.5%, indicating that the present device can improve the consistency of the thickness of the negative electrode sheet after rolling; and by attaching Figure 6 It can be found that the rebound thickness of the electrode sheet 7 rolled by the present device after 0.5h, 1h and 2h is smaller than the rebound thickness of the electrode sheet 7 rolled by a single roller, indicating that the present device can effectively reduce the rebound of the negative electrode sheet 7 after rolling.

[0037] Embodiment 2:

[0038] Prepare the positive electrode slurry with the above ratio, and apply it with a thickness of 300μm. After coating and drying, cut the electrode to be tested into rectangular sizes of about 5cm×10cm, which are recorded as A1, B1, C1 and A2, B2, C2 respectively. A1, B1, and C1 are rolled into electrode pieces 7 with compaction densities of 2.0g / cm3, 2.1g / cm3, and 2.2g / cm3 respectively using a single roller machine. At the same time, use this device to roll A2, B2, and C2 into electrode pieces 7 with compaction densities of 2.0g / cm3, 2.1g / cm3, and 2.2g / cm3 respectively. Measure the equally spaced thickness of the electrode pieces 7 after rolling and the thickness that rebounds after 0.5h and 1h (as shown in Tables 3 and 4), and draw a curve graph (as shown in the attached figure). Figure 8 shown).

[0039] Table 3: Statistics of cathode electrode thickness at different measuring points after rolling

[0040]

[0041]

[0042] Table 4: Statistics of cathode pole piece rebound thickness at different times after rolling

[0043]

[0044]

[0045] Attached Figure 7 The graph is a data curve of the thickness measurement of the positive electrode sheet 7 after rolling by different devices. It can be seen from the figure that under three different compaction densities, the thickness uniformity of the electrode sheet 7 rolled by the present device is better than that of the electrode sheet rolled by a single roller, the curve fluctuation is small, and the standard deviation is within 0.5%, indicating that the present device can improve the uniformity of the thickness of the positive electrode sheet 7 after rolling; and by attaching Figure 8 It can be found that the rebound thickness of the electrode sheet after rolling using the present device after 0.5h and 1h is smaller than the rebound thickness of the electrode sheet 7 after rolling using a single roller machine, indicating that the present device can effectively reduce the rebound of the positive electrode sheet 7 after rolling.

[0046] Result analysis: Based on the test results of Example 1 and Example 2, it can be seen that the device for rolling the electrode sheet for buckle power provided in this patent can reduce the adverse effect of the electrode sheet rebounding after rolling, and at the same time improve the uniformity of the compaction density of the electrode sheet 7 after rolling.

[0047] The working principle of the utility model is as follows: the device is placed on the experimental table through the supporting legs 18, and then the infrared heating plate 8 and the motor 11 are started. The motor 11 drives the active synchronous wheel 13 to rotate through the reducer 12, and the rotating active synchronous wheel 13 drives the driven synchronous wheel 14 to rotate through the synchronous belt 15, so that the small compaction roller 3 and the large compaction roller 4 rotate synchronously, and the pole piece 7 is abutted against the guide roller 17 on the side of the first support frame 5, and the pole piece 7 is passed between the two infrared heating plates 8, so that one end of the pole piece 7 contacts the small compaction roller 3 and is rolled by the two small compaction rollers 3, and the pole piece 7 after rolling contacts the large compaction roller 4 and is rolled by the two large compaction rollers 4, and the pole piece 7 rolled by the two large compaction rollers 4 abuts against the discharging bracket 9 and is discharged from the guide roller 17 on the side of the second support frame 6.

[0048] The utility model first heats the two sides of the pole piece 7 respectively through two infrared heating plates 8, and then uses a small compaction roller 3 to roll the pole piece 7 with a small reduction amount of 40%; finally, uses a large compaction roller 4 to roll the pole piece 7 with a large reduction amount of 60%. After rolling, the pole piece 7 can effectively reduce rebound, and the thickness of the pole piece 7 can maintain good consistency.

[0049] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the embodiments disclosed above are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. A laboratory rolling device for reducing pole piece rebound, characterized in that: The invention comprises a base frame (1) and a driving assembly (2), wherein two small compacting rollers (3) arranged horizontally are rotatably connected between two columns on one side of the base frame (1), and two large compacting rollers (4) arranged horizontally are rotatably connected between the two middle cross beams of the base frame (1), and a first support frame (5) is installed on the side walls of the two columns of the base frame (1) located on the side of the small compacting roller (3), and a second support frame (6) is installed on the side walls of the two columns of the base frame (1) away from the small compacting roller (3), and an infrared heating plate (8) for heating the electrode (7) is symmetrically installed between the two first support frames (5), and a discharging bracket (9) is installed on the upper ends of the two second support frames (6), and a mounting platform (10) is installed on the base frame (1), and the driving assembly (2) is installed on the mounting platform (10), and the driving assembly (2) drives the small compacting roller (3) and the large compacting roller (4) to rotate.

2. A laboratory rolling device for reducing pole piece rebound according to claim 1, characterized in that: The driving assembly (2) comprises a motor (11) and a reducer (12) mounted on a mounting platform (10); the output end of the motor (11) is connected to the input end of the reducer (12); the output end of the reducer (12) is connected to the rotating shaft of the large compaction roller (4); a driving synchronous wheel (13) and a driven synchronous wheel (14) are respectively mounted on the rotating shafts of the large compaction roller (4) and the small compaction roller (3); and a synchronous belt (15) is sleeved on the outer sides of the driving synchronous wheel (13) and the driven synchronous wheel (14).

3. A laboratory rolling device for reducing pole piece rebound according to claim 1, characterized in that: A cover (16) for covering the driving assembly (2) is installed on the base frame (1).

4. A laboratory rolling device for reducing pole piece rebound according to claim 1, characterized in that: A material guide roller (17) is rotatably connected between the two first support frames (5) and the two second support frames (6).

5. A laboratory rolling device for reducing pole piece rebound according to claim 1, characterized in that: A plurality of supporting legs (18) are installed on the bottom side of the base frame (1).

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