Lithium battery negative pole piece thinning area rolling device and pole piece rolling machine

Abstract

The invention discloses a rolling device for a thinning area of a negative pole piece of a lithium battery and a pole piece rolling machine. The lithium battery negative pole piece thinning area rolling device comprises a roller, and the roller is composed of a pole lug reinforcing roller used for forming a pole lug reinforcing rib in a pole piece pole lug area in a rolling mode and at least one thinning area roller connected with the pole lug reinforcing roller and used for conducting rolling thinning on the pole piece thinning area. And the thinning area roller and the tab reinforcing roller are coaxially arranged and are positioned at the end part of the tab reinforcing roller. In the actual production process, effective rolling of the lithium battery negative pole piece thinning area can be achieved through the rolling device for the lithium battery negative pole piece thinning area, materials in the thinning area are completely pressed, therefore, the material falling situation in the cutting, winding and ultrasonic welding process is reduced, the short circuit risk is reduced, and the yield and safety of lithium battery production are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery production, in particular to a lithium battery negative electrode sheet thinning area rolling device and an electrode sheet rolling machine. BACKGROUND

[0002] In the production process of lithium batteries, the rolling process of the negative electrode sheet is crucial. Currently, the negative electrode sheet has a thinning area, which cannot be effectively rolled in the traditional rolling process, and is prone to material dropping. The material dropping problem not only affects the production quality of lithium batteries, but also increases the risk of short circuit in the subsequent short circuit test process, seriously threatening the safety and stability of lithium batteries.

[0003] The CN2024102499662 patent file proposes an electrode sheet production process system, which sets a laser cleaning unit before and after the rolling process, uses a high-energy laser beam to remove active substances in the thinning area, and avoids subsequent welding and short circuit problems. After laser cleaning, the electrode sheet is compacted by rolling to enhance the bonding force. Laser cleaning of the thinning area relies on the thermal stripping effect of high-energy laser beams to remove surface substances, but the current collector of the negative electrode sheet is an ultra-thin copper foil which is extremely sensitive to heat. The periodic thermal shock of pulsed laser will cause uneven local thermal expansion of the copper foil, forming a wavy deformation, affecting the flatness of the electrode sheet, and increasing the process difficulty of subsequent rolling and winding.

[0004] Therefore, it is of great significance to design a device that can effectively roll the lithium battery negative electrode sheet thinning area during laser cutting production to improve the key quality of lithium battery production. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings and defects of the prior art, and to provide a lithium battery negative electrode sheet thinning area rolling device and an electrode sheet rolling machine. In actual production process, the lithium battery negative electrode sheet thinning area rolling device can effectively roll the lithium battery negative electrode sheet thinning area, so that the thinning area material is completely compacted, thereby reducing the material dropping during cutting, winding and ultrasonic welding, reducing the risk of short circuit, and improving the yield and safety of lithium battery production.

[0006] One purpose of the present application is to provide a lithium battery negative electrode sheet thinning area rolling device, which comprises a rolling mill, the rolling mill is composed of an ear strengthening roller for rolling the ear of the electrode sheet to form an ear strengthening rib, and at least one thinning area roller for rolling the thinning area of the electrode sheet, the thinning area roller is coaxially arranged with the ear strengthening roller and located at the end of the ear strengthening roller.

[0007] Preferably, the surface of the ear strengthening roller is uniformly arranged with strengthening rib strips, and the strengthening rib strips are arranged apart in the rotation direction.

[0008] Preferably, the two ends of the reinforcing rib have edge chamfers to prevent the thinning area from falling off or having poor indentation caused by rolling.

[0009] Preferably, the surface of the thinning area roller is a smooth surface.

[0010] Preferably, the thinning area compaction end of the thinning area roller has an edge chamfer for the transition between the compaction area and the non-compaction area to avoid causing poor indentation.

[0011] Preferably, the roller is provided with a guide shaft and two guide bearings, and the guide shaft is rotationally connected to the roller body.

[0012] Preferably, the guide bearing is provided with an over-roller positioning block, which includes two arc-shaped positioning blocks that embrace the guide shaft and are connected by screws.

[0013] Preferably, the diameter of the bearing top block of the guide bearing is greater than the diameter of the over-roller positioning block.

[0014] Preferably, the tab reinforcing roller is integrally formed with the thinning area roller, and the diameter of the roller is stepped down from the middle to the ends of the roller body.

[0015] Another object of the present application is to provide a tab roller press, which comprises the lithium battery negative tab thinning area roller press device.

[0016] The present application can precisely press the thinning area of the negative tab during the laser cutting process by the specially designed thinning area roller, which can completely press the thinning area material, greatly reduces the material falling phenomenon during cutting, winding, and ultrasonic welding, effectively solves the material falling problem, improves the integrity and consistency of the tab, reduces the short circuit risk, effectively avoids the short circuit problem caused by material falling in the subsequent process, significantly improves the safety and stability of the lithium battery, and improves the production yield. The present application can quickly and accurately press the thinning area of the negative tab without manual intervention, reduces the downtime adjustment time during production, can process more tabs per unit time compared to the traditional rolling method, and greatly improves the production efficiency of the lithium battery negative tab. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a use schematic diagram of the lithium battery negative tab thinning area roller press device of the present application.

[0018] Fig. 2 is the roll end local schematic view of the lithium battery negative electrode sheet thinning area roll pressing device of the present application.

[0019] Fig. 3 is the assembly schematic view of the guide shaft and guide bearing and the over roll positioning roll of the lithium battery negative electrode sheet thinning area roll pressing device of the present application.

[0020] Fig. 4 is the assembly schematic view of the guide shaft and guide bearing of the lithium battery negative electrode sheet thinning area roll pressing device of the present application. DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] In the exemplary embodiments of the present application, the lithium battery negative electrode sheet thinning area roll pressing device adopts the way of adding smooth rollers on the tab reinforcing rib device to form thinning area rollers, so as to realize the synchronous processing of the roll pressing of the negative electrode sheet thinning area and the tab reinforcing rib.

[0023] Referring to Figs. 1 to 4 In the exemplary embodiments of the present application, the lithium battery negative electrode sheet thinning area roll pressing device includes a roll, which is composed of a tab reinforcing roll for roll pressing the tab ear area 3 of the processed sheet 1 to form a tab reinforcing rib and at least one thinning area roll 6 for roll pressing the sheet thinning area 2, the thinning area roll is coaxially arranged with the tab reinforcing roll and located at the end of the tab reinforcing roll.

[0024] The lithium battery negative electrode sheet thinning area roll pressing device of the present application can simultaneously process the thinning area 2 and the reinforcing rib of the tab ear area 3 in the sheet 1, and the reinforcing rib formed in the tab ear area is a parallel arranged rib, so that the tab ear area forms a convex-concave groove and a convex-concave surface.

[0025] The thinning area roll 6 and the tab reinforcing roll 7 of the present application are both made of high-strength alloy steel, and the surface is specially treated, which has high hardness, high wear resistance and good surface finish.

[0026] In the present application, the surface of the tab reinforcing roll is uniformly arranged with reinforcing rib strips, and the reinforcing rib strips are arranged apart along the rotation direction. Preferably, the two ends of the reinforcing rib strip have edge chamfers, such as R0.5mm, to prevent the thinning area from dropping and causing poor indentation during roll pressing.

[0027] In the embodiment of the present application, the surface of the thinning area roller is a smooth surface, and preferably, the thinning area compression end of the thinning area roller has an edge chamfer, such as R0.5mm, for the transition of the compression area and the non-compression area to avoid causing undesirable pressure marks.

[0028] In the embodiment of the present application, the roller is provided with a guide shaft and guide bearings 3.1, the guide bearings 3.1 are two, and the guide shaft is rotationally connected through the roller body. The double-bearing design is used to adapt to the radial and axial loads in two directions, which is different from the single-row bearing composed of a group of rolling elements; preferably, the guide shaft is made of No. 20 steel material with good mechanical properties, can not be deformed under high-speed rotation and vibration, and has high tensile strength which remains unchanged under a certain pressure.

[0029] In the embodiment of the present application, the guide bearing is arranged with an over-roller positioning block 5, the over-roller positioning block includes two arc-shaped positioning blocks 2.2, and a 1mm assembly gap 2.3 is left in the middle, the two arc-shaped positioning blocks are clamped on the guide shaft and connected by two M3 internal hexagonal screws 2.2, which can fix the two arc-shaped positioning blocks 2.2 on one hand, and make the positioning block tightly clamp the guide shaft to prevent the guide bearing from shaking during movement on the other hand.

[0030] In the embodiment of the present application, the diameter of the bearing top block of the guide bearing is greater than the diameter of the over-roller positioning block, such as the bearing ring top block 2.4 is 0.5mm higher than the over-roller positioning block, and this avoidance design effectively reduces the wear of the bearing and can prevent metal dust from polluting the material area.

[0031] In the embodiment of the present application, the tab reinforcing roller is integrally formed with the thinning area roller, the thinning area roller and the tab reinforcing rib roller are an integral mechanism, and are installed on the upper part of the rack through the guide bearing and the guide shaft, can freely rotate around the axis, and are driven to move through the movement of the pole piece to form the tab reinforcing rib on the surface of the pole piece and form the thinning area.

[0032] In the embodiment of the present application, the diameter of the tab reinforcing roller is greater than the diameter of the thinning area roller, and the diameter of the roller is stepped reduced from the middle part to the two ends of the roller body. In the embodiment of the present application, the two ends of the lithium ion battery pole piece roller are set to be stepped reduced by improving the roller, so that the main diameter of the roller gradually decreases towards the two ends, which can leave enough space at the two ends to prevent overpressure when the roller is elastically bent, make the stress of the thinning area more uniform, and achieve good thinning area rolling effect.

[0033] When the lithium battery negative pole piece rolling device of the present application is used, the following operations are performed: Preparation work before rolling: check the range, thickness and base of the negative electrode sheet thinning area, ensure that the base is flat and free of impurities, and confirm that it meets the rolling requirements; check whether there are impurities on the surface of the thinning area roll and the tab reinforcing rib over roll, check the equipment state to reach the processing standard.

[0034] Thinning and reinforcing rib synchronous processing: test processing 1m to 2m to check the rolling effect, synchronize the calibration of the thickness sensor value, ensure that the actual value is consistent with the thickness sensor value, set the thickness alarm range such as (150-155μm), and continuously run the equipment to ensure that the rolling (flatness, thickness) reaches the index.

[0035] Key technical parameters: the thinning and rolling pressure and the tab reinforcing rib pressure are set to the same 0.2MPa, the thinning area roll and the tab reinforcing rib cleaning frequency is once per shift, and the thickness sensor calibration is once a day (calibration method 200μm standard block verification error ±1μm).

[0036] Rolling condition requirements: a) environmental cleanliness: it needs to be carried out in a clean workshop to avoid dust pollution of the surface of the electrode sheet, which may cause micro-short circuit of the battery. b) environmental humidity: control in 30%-50%RH, too high humidity may cause the electrode sheet to absorb moisture, and too low humidity may cause static adsorption of dust.

[0037] The device of the present application combines the tab reinforcing rib device and the roll thinning area device, and through high-precision positioning sensors and displacement sensors, the roll thinning area of the lithium battery negative electrode sheet can be rolled, the risk of negative electrode thinning area dropping is effectively reduced, and the product qualification rate is improved.

[0038] In addition, by adopting an automatic control system, the operator only needs to input related parameters, and the device can automatically complete the positioning, roll thinning area of the negative electrode sheet and other operations, reducing manual intervention, improving production efficiency and reducing production cost. In the embodiment of the present application, the rolls are arranged in an upper and lower spaced manner with parallel axes to form a roll pair for rolling the negative electrode sheet, wherein the rolls of the rolling mechanism are made of special materials and surface treatment processes, which improves the wear resistance and service life of the rolls, and at the same time ensures the surface quality of the negative electrode sheet.

[0039] The embodiment of the present application also provides a negative electrode sheet rolling machine comprising the lithium battery negative electrode sheet thinning area rolling device.

[0040] The above shows and describes the basic principles and main features of the present application and the advantages of the present application, and it is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be considered as exemplary and non-limiting, the scope of the application being defined by the appended claims and not by the above description, therefore all variations falling within the meaning and the scope of the equivalent elements of the claims are intended to be encompassed by the application.

[0041] Furthermore, it should be understood that although the present specification describes only one embodiment for carrying out the application, not every embodiment need contain only one independent technical solution, and the present specification is described in this way only for the sake of clarity, and the skilled person should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that the skilled person can understand.

Claims

1. A rolling device for thinning the negative electrode sheet of a lithium battery, characterized in that, It includes a roll consisting of an electrode reinforcing roll for forming electrode reinforcing ribs in the electrode tab area and at least one thinning roll connected to the electrode reinforcing roll for thinning the electrode tab thinning area. The thinning roll is coaxially arranged with the electrode reinforcing roll and located at the end of the electrode reinforcing roll.

2. The lithium battery negative electrode sheet thinning roll forming device according to claim 1, characterized in that, The surface of the reinforcing roller of the electrode tab is uniformly arranged with reinforcing ribs, which are spaced apart along the direction of rotation.

3. The lithium battery negative electrode sheet thinning area rolling device according to claim 2, characterized in that, The reinforcing ribs have chamfered edges at both ends to prevent material loss and poor indentation in the thinning area caused by roller pressing.

4. The lithium battery negative electrode sheet thinning roll forming device according to claim 1, characterized in that, The surface of the thinning zone roller is a smooth surface.

5. The lithium battery negative electrode sheet thinning roll forming device according to claim 1, characterized in that, The thinning zone roller has a chamfered edge at the compaction end of the thinning zone, which is used for the transition between the compaction zone and the non-compaction zone to avoid causing undesirable indentations.

6. The lithium battery negative electrode sheet thinning roll forming device according to claim 1, characterized in that, The roll is equipped with a guide shaft and two guide bearings. The guide shaft is rotatably connected to the roll body of the roll.

7. The lithium battery negative electrode sheet thinning roll forming device according to claim 6, characterized in that, The guide bearing is arranged with roller positioning blocks, which include two arc-shaped positioning blocks. The two arc-shaped positioning blocks are mounted on the guide shaft and connected by screws.

8. The lithium battery negative electrode sheet thinning area rolling device according to claim 7, characterized in that, The diameter of the bearing top block of the guide bearing is larger than the diameter of the roller positioning block.

9. The lithium battery negative electrode sheet thinning area rolling device according to claim 1, characterized in that, The reinforcing roller and the thinning zone roller are integrally formed. Preferably, the diameter of the roller is reduced in a multi-step manner from the middle of the roller body to both ends.

10. An electrode roll press, characterized in that, The lithium battery negative electrode sheet thinning area rolling device includes any one of claims 1-9.

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