A dry electrode preparation device for improving the consistency of a diaphragm

Abstract

The utility model discloses a kind of dry method electrode preparation devices for improving diaphragm consistency, including A face film-forming device and B face film-forming device;The A face film-forming device and B face film-forming device all include first diameter support roller and second diameter rolling mill, and the diameter of the first diameter support roller is greater than the diameter of second diameter rolling mill;The first diameter support roller includes left force support roller and right force support roller;Second diameter rolling mill sequentially includes film-forming roller, first thinning roller, second thinning roller, fixed roller and composite roller;The axis connecting line between second thinning roller and first thinning roller and fixed roller is acute angle included angle.The utility model applies support force through support roller on the back of work roll, solve deflection influence problem when work roll rolling;Subsection type misplacement arrangement is adopted, and the diameter of roll, arrangement position, angle are designed, reduce roller spacing fluctuation, solve uneven stress, the problem of poor film-forming consistency.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a dry electrode preparation device for improving film uniformity. Background Technology

[0002] With the rapid development of the new energy industry, lithium-ion batteries are playing an increasingly important role. Lithium-ion batteries possess numerous advantages, including a high voltage platform, high specific energy, long cycle life, and good rate performance. Currently, lithium-ion battery manufacturing processes are divided into two types: wet processing and dry processing. The wet process involves stirring and dispersing conductive agents, binders, and active materials in a solvent to meet coating requirements. The dry process, on the other hand, involves directly stirring, dispersing, and fibrillating the active materials, conductive agents, and binders before roll forming. Because no solvent is added during the dry processing, the binder is uniformly dispersed in a fibrillated state, coating the active materials, resulting in a tighter contact between the active materials and the conductive agents. Therefore, dry-process electrode films have advantages such as high energy density and long cycle life.

[0003] In the rolling process of lithium battery electrodes, the precision requirements for electrodes are becoming increasingly stringent due to the energy density of the batteries. Existing dry electrode preparation devices suffer from uneven force distribution and poor film formation consistency during material rolling. This is primarily because limited equipment space makes independent pressurization difficult; film formation pressure must be applied from both ends. During pressure transmission, the roller spacing cannot be precisely controlled, causing roller vibration and affecting film formation consistency. Excessive thickness uniformity alters the migration path of lithium ions during charging and discharging, increasing the battery's internal resistance and reducing its specific capacity and cycle stability. Furthermore, the properties of some materials make it difficult to achieve uniform pressure transmission during film formation, also leading to abnormal fluctuations in the roller spacing. Summary of the Invention

[0004] The purpose of this invention is to provide a dry electrode preparation device that improves the uniformity of film formation, effectively enhances the uniformity of dry electrode film formation, and extends the service life of the rollers.

[0005] To achieve the above objectives, the technical solution provided by this utility model is as follows: This application provides a dry electrode fabrication apparatus for improving film uniformity, comprising: an A-side film forming apparatus and a B-side film forming apparatus; both the A-side film forming apparatus and the B-side film forming apparatus include a first diameter support roller and a second diameter roller, wherein the diameter of the first diameter support roller is larger than the diameter of the second diameter roller. The first diameter support roller includes a left force-bearing support roller and a right force-bearing support roller; The second diameter roll comprises, in sequence, a film-forming roll, a first thinning roll, a second thinning roll, a fixed roll, and a composite roll; the fixed roll is a fixed, non-rotating roll, and the film-forming roll, the first thinning roll, the second thinning roll, and the composite roll are all rotating rolls; The line connecting the axis of the second thinning roller to the axis of the first thinning roller and the fixed roller forms an acute angle.

[0006] To optimize the above technical solution, the specific limitations also include: The diameter of the first diameter support roller is 1.5 to 2.5 times the diameter of the second diameter roller. The diameter of the first diameter support roller is 600~900mm; the width of the second diameter roller is 600~1000mm.

[0007] Furthermore, in the A-side film forming apparatus, the second diameter rollers from left to right are: A-side film forming roller, A-side first thinning roller, A-side second thinning roller, A-side fixing roller, and A-side composite roller; the left side of the A-side film forming roller is pressed by the first left force-bearing support roller, and the right side of the A-side composite roller is pressed by the first right force-bearing support roller. In the B-side film forming apparatus, the second diameter rollers from left to right are: B-side composite roller, B-side fixed roller, B-side second thinning roller, B-side first thinning roller, and B-side film forming roller; the left side of the B-side composite roller is pressed by the second left force-bearing support roller, and the right side of the B-side film forming roller is pressed by the second right force-bearing support roller.

[0008] Furthermore, an A-side loading bin is provided above the A-side film-forming roller and the A-side first thinning roller, and a B-side loading bin is provided above the B-side film-forming roller and the B-side first thinning roller.

[0009] The area between the A-side fixed roller and the A-side composite roller is the film exit position of the A-side film forming device, and the area between the B-side composite roller and the B-side fixed roller is the film exit position of the B-side film forming device.

[0010] Preferably, a first film detection device is provided on the outside of the film exit position of the A-side film forming device, and a second film detection device is provided on the outside of the film exit position of the B-side film forming device.

[0011] The angle between the second thinning roller and the axis connecting the first thinning roller and the fixed roller is 10°~45°.

[0012] It also includes a current collector unwinding mechanism and a dry electrode winding mechanism. The current collector unwinding mechanism is used to unwind the current collector to form a dry electrode with composite front and back films through the B-side film forming device and the A-side film forming device. The dry electrode winding mechanism is used to wind up the obtained dry electrode.

[0013] The bottom of the fixed roller is equipped with a cutting mechanism.

[0014] Compared with the prior art, the beneficial effects of this utility model are: This invention employs a segmented, staggered arrangement, with large rollers supporting small rollers. The diameter, arrangement, and angle of the rollers are carefully designed to effectively apply pressure to each roller and make them easily controllable, reducing roller spacing fluctuations and solving problems of uneven stress and poor film formation consistency. Furthermore, a detection device is installed to monitor and control the film-forming electrode effect in real time, as detailed below: (1) This utility model adds a support roller with greater rigidity and larger diameter to the back of the work roll. The support roller applies a supporting force to the work roll, which suppresses the bending deformation of the work roll under the rolling pressure and solves the deflection problem generated during the rolling of the work roll.

[0015] (2) In this utility model, the axis connecting the second thinning roller and the first thinning roller and the fixed roller forms an acute angle. By arranging the rollers at such an angle, the independent control of the roller spacing is formed, which makes the control accuracy better, the roller jump smaller, and the film thickness uniformity higher.

[0016] (3) The present invention also provides a film detection device at the film outlet of the segmented film forming device. By adopting the corresponding segmented detection method, the film thickness and surface density can be controlled and adjusted online. The control process does not require machine shutdown, which improves the overall utilization rate of the preparation device and increases the product yield. Attached Figure Description

[0017] Figure 1 : A schematic diagram of the dry electrode preparation device for improving film uniformity according to this utility model.

[0018] In the diagram: 1-A-side film forming device, 2-B-side film forming device, 3-first diameter support roller, 4-second diameter roller, 5-A-side film forming roller, 6-A-side first thinning roller, 7-A-side second thinning roller, 8-A-side fixed roller, 9-A-side composite roller, 10-first left force-bearing support roller, 11-first right force-bearing support roller, 12-B-side composite roller, 13-B-side fixed roller, 14-B-side second thinning roller, 15-B-side first thinning roller, 16-B-side film forming roller, 17-second left force-bearing support roller, 18-second right force-bearing support roller, 19-A-side loading bin, 20-B-side loading bin, 21-first film detection device, 22-second film detection device, 23-current collector unwinding mechanism, 24-dry electrode winding mechanism. Detailed Implementation

[0019] The present invention will be further described in detail below through specific embodiments. However, it should not be construed as the scope of the present invention being limited to the following embodiments. All technologies implemented based on the present invention fall within the scope of the present invention.

[0020] In the description of this utility model, it should also be noted that: The orientations or positional relationships described herein are based on the relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In this embodiment, for the sake of description, to illustrate... Figure 1 The left is the direction to the left of the center.

[0021] Furthermore, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise expressly specified and limited, the specific meanings of the above terms in this utility model can be understood by those skilled in the art based on the specific circumstances.

[0022] This invention provides a dry electrode fabrication apparatus that improves film uniformity, such as... Figure 1 As shown, it includes: A-side film forming device 1 and B-side film forming device 2; both A-side film forming device 1 and B-side film forming device 2 include a first diameter support roller 3 and a second diameter roller 4, the diameter of the first diameter support roller 3 is larger than the diameter of the second diameter roller 4; The first diameter support roller 3 includes a left force-bearing support roller and a right force-bearing support roller; The second diameter roll 4 includes a film-forming roll, a first thinning roll, a second thinning roll, a fixed roll, and a composite roll; the fixed roll is a fixed, non-rotating roll, while the film-forming roll, the first thinning roll, the second thinning roll, and the composite roll are all rotating rolls; The axis connecting the second thinning roller, the first thinning roller, and the fixed roller forms an acute angle.

[0023] The film outlet positions of the A-side film forming device 1 and the B-side film forming device 2 of this utility model are arranged in a corresponding manner.

[0024] During the rolling (compacting, calendering) process of dry electrodes, two relatively rotating work rolls apply enormous linear pressure to the electrode powder or electrode sheet, which is distributed along the axial direction of the roll surface. Ideally, the pressure should be uniform across the entire width of the roll surface. However, since the roll itself is a slender cylinder, it will undergo deflection deformation under the enormous linear pressure. The consequence of this deformation is that the electrode material experiences less pressure in the middle of the roll surface and greater pressure at both ends, resulting in uneven pressure distribution. This leads to inconsistent thickness and areal density of the dry electrode film, which in turn affects battery performance.

[0025] Specifically, in some dry electrode systems, the powder particle size is too small and the material is brittle and hard, resulting in uneven pressure transmission during the powder film formation process and increased fluctuations in the roller spacing. Using a small-diameter film-forming roller can better achieve film formation. Based on the characteristic that small-diameter powders require greater linear pressure for film formation, the diameter of the film-forming roller should not be too large. As the equipment capacity is gradually increased, a wider width is needed to improve production efficiency. Therefore, the length-to-diameter ratio increases, and the equipment deflection deformation increases, which will affect the consistency of the film. Under the same width conditions, by utilizing the principle that the larger the roller diameter, the smaller the deformation, adding large rollers at both ends to support the force can reduce the deformation of the film-forming roller.

[0026] Most current dry preparation equipment uses an integrated horizontal rolling mill, which has extremely high requirements for equipment capacity. The consistency of the film formation improves with the increase of thinning times. The more pressure is transmitted through the rollers at both ends, the more difficult it is to control the roller spacing, which greatly affects the consistency between the film and the electrode. By arranging the thinning rollers in segments and staggering them, and adding independent roller drive mechanisms, precise control of the roller spacing can be achieved. At the same time, online detection, adjustment and control functions of areal density and thickness can also be realized.

[0027] This invention adds one or more support rollers with greater rigidity and larger diameter to the non-working side (back side) of the work roll, which are in close contact with the work roll. The support rollers apply a supporting force to the work roll, effectively suppressing the bending deformation of the work roll under rolling pressure. This significantly reduces the impact of deflection deformation during rolling, maintaining a high degree of parallelism or near-ideal parallelism within the effective roll width. The thickness deviation of the final compacted dry electrode sheet is significantly reduced, and the consistency of thickness / area density is greatly improved, enhancing the performance of the final battery product. At the same time, the uniform pressure distribution also helps to extend the service life of the work roll and enables the equipment to adapt to the production needs of higher rolling pressure, faster production speed, and wider electrode width.

[0028] In this invention, the force-bearing support rollers on both sides are used for support and do not participate in the feeding, film formation, thinning, and lamination processes; only one roller is fixed in each film-forming device and is regarded as the reference position.

[0029] In some embodiments, a cutting mechanism is provided at the bottom of the fixed roller. This invention improves the uniformity of dry electrode film formation and extends the service life of the rollers by adding a force-bearing roller and changing the arrangement of various mechanisms.

[0030] The diameter of the first diameter support roller 3 is 1.5 to 2.5 times the diameter of the second diameter roller 4. In some embodiments, the diameter of the first diameter support roller 3 is 600 to 900 mm, and the width of the second diameter roller 4 is preferably 600 to 1000 mm.

[0031] This invention uses a large-diameter first-diameter support roller 3 to support a small-diameter second-diameter roller 4.

[0032] In some implementation methods: In the A-side film forming apparatus 1, the second diameter rollers 4 are arranged from left to right as follows: A-side film forming roller 5, A-side first thinning roller 6, A-side second thinning roller 7, A-side fixing roller 8, and A-side composite roller 9; the left side of the A-side film forming roller 5 is pressed by the first left force support roller 10, and the right side of the A-side composite roller 9 is pressed by the first right force support roller 11. In the B-side film forming apparatus 2, the second diameter rollers 4 are arranged from left to right as follows: B-side composite roller 12, B-side fixed roller 13, B-side second thinning roller 14, B-side first thinning roller 15, and B-side film forming roller 16; the left side of the B-side composite roller 12 is pressed by the second left force support roller 17, and the right side of the B-side film forming roller 16 is pressed by the second right force support roller 18.

[0033] Above the A-side film forming roller 5 and the A-side first thinning roller 6, there is an A-side loading bin 19, and above the B-side film forming roller 16 and the B-side first thinning roller 15, there is a B-side loading bin 20.

[0034] The area between the A-side fixed roller 8 and the A-side composite roller 9 is the film exit position of the A-side film forming device 1, and the area between the B-side composite roller 12 and the B-side fixed roller 13 is the film exit position of the B-side film forming device 2.

[0035] This invention also examines the influence of the arrangement angle of each roller in the second diameter roll 4. Preferably, the angle between the axis connecting the second thinning roll 7 and the first thinning roll 6 on the A side and the fixed roll 8 on the A side is 10°~45°; the angle between the axis connecting the second thinning roll 14 and the fixed roll 13 on the B side and the first thinning roll 15 on the B side is 10°~45°.

[0036] The angular arrangement of the rolls allows for independent control of the roll spacing, resulting in better control precision, less roll runout, and high consistency in diaphragm thickness, which is then combined with the current collector for thermal bonding.

[0037] In some embodiments, the current collector unwinding mechanism 23 and the dry electrode winding mechanism 24 are also included. The current collector of the current collector unwinding mechanism 23 passes through the exit position of the film forming device 2 on the B side and the film forming device 1 on the A side to form the dry electrode of the composite film on both sides, which is then wound up by the dry electrode winding mechanism 24.

[0038] In some embodiments, a first film detection device 21 is provided on the outside of the film exit position of the A-side film forming device 1, and a second film detection device 22 is provided on the outside of the film exit position of the B-side film forming device 2.

[0039] This invention uses a current collector (carbon-coated current collector) as a carrier to achieve segmented membrane composite. A detection device is used to monitor and control the membrane deposition effect in real time. The composite and real-time detection method is as follows: A-side membrane composite is performed using an A-side membrane deposition device 1. The thickness and areal density of the A-side membrane are detected by a first membrane detection device 21 located outside the membrane exit position of the A-side membrane deposition device 1. This calculation process requires subtracting the carbon-coated current collector data. Then, the membrane is thermally composited with the B-side membrane to form an electrode. The B-side membrane thickness and areal density data are obtained by internal calculation and analysis using an online detection device and subtracting the measured A-side data.

[0040] This invention employs segmented detection, enabling online control and adjustment of film thickness and areal density. The control process requires no machine shutdown, which not only improves the overall utilization rate of the preparation device but also greatly improves product yield.

[0041] The technical solution of this utility model will be further described in detail below with reference to specific embodiments: Example 1 The film-forming devices on both sides of the second diameter roll are selected with a width of 900mm, a film-forming roll diameter of 300mm, a thinning roll diameter of 300mm, a composite roll diameter of 300mm, and a first diameter support roll diameter of 600mm. The film is prepared using an LMFP system (lithium manganese iron phosphate) and raw materials such as conductive agents and binders, after dispersion, homogenization, mixing, and fibrillation. The film-forming temperature is 60-150℃; the applied pressure is 10-50T; the circular runout of the film-forming roll is ≤5μm; the film thickness error is ±1μm (film thickness >100μm); and the areal density error is controlled within 3%. The angle between the axis connecting the second thinning roller 7 and the first thinning roller 6 on side A and the fixed roller 8 on side A is 30°; the angle between the axis connecting the second thinning roller 14 and the fixed roller 13 on side B and the first thinning roller 15 on side B is 30°.

[0042] In this embodiment, the film outlet positions of the A-side film forming device and the B-side film forming device are arranged correspondingly.

[0043] Since the device is basically mirror-shaped except for the fixed rollers, the number of compounding operations can be increased. The compounding method is always counter-rotating rollers at the same speed. Increasing the number of operations does not affect the performance of the device.

[0044] Online detection device: Since some of the energy of beta rays is absorbed by the electrode when they penetrate a material, the intensity of the rays decreases. The intensity of the decrease is negatively exponentially related to the surface density of the electrode. Therefore, non-destructive, non-contact measurement of the surface density of the electrode can be achieved.

[0045] Under interference-free conditions, since the greater the surface density of the material through which X-rays penetrate, the faster the intensity of the X-rays attenuates, the surface density of the electrode can be calculated by measuring the intensity of the X-rays before and after penetrating the electrode. However, this measurement method is not applicable to films with copper foil as the carrier.

[0046] The laser thickness gauge utilizes the interaction between a laser beam and the surface of the object being measured. When the laser beam strikes the surface of the membrane, part of the laser light is reflected. This reflected light is captured and analyzed by the receiver of the laser thickness gauge. By analyzing the characteristics of the reflected light (such as time, angle, and intensity), the thickness of the object being measured can be calculated.

[0047] Areal density and thickness measurement can be integrated into a single device. First, areal density data needs to be measured. Then, through built-in calculation logic, the relationship between thickness and areal density is analyzed to obtain thickness data. This type of device is relatively mature and can be used directly. After measurement and data analysis by the online detection device, the data is fed back to the film formation and thinning areas to control parameters such as temperature, pressure, roller speed, and roller spacing of the device, thereby realizing the online adjustment function of electrode thickness and areal density.

[0048] Through testing, Example 1 can produce a uniform electrode sheet with excellent film consistency. Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that: the first thinning roller 6 and the second thinning roller 7 on surface A are in a straight line with the fixed roller 8 on surface A, that is, the angle between the axis connecting the second thinning roller 7 and the first thinning roller 6 on surface A and the fixed roller 8 on surface A is 5°; the fixed roller 13 and the second thinning roller 14 on surface B are in a straight line with the first thinning roller 15 on surface B, that is, the angle between the axis connecting the second thinning roller 14 and the fixed roller 13 on surface B and the first thinning roller 15 on surface B is 5°.

[0049] Test results show that the film thickness uniformity and areal density control are significantly worse than those in Example 1.

[0050] Comparative Example 2 Comparative Example 1 is basically the same as Example 1, except that: the angle between the axis connecting the second thinning roller 7 and the first thinning roller 6 on the A side and the fixed roller 8 on the A side is 60°; the angle between the axis connecting the second thinning roller 14 and the fixed roller 13 on the B side and the first thinning roller 15 on the B side is 60°.

[0051] Test results showed that an excessively large angle led to poor material flow, uncontrolled tension, and uneven stress distribution, resulting in slightly lower product quality.

[0052] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the present utility model's technical solution and based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A dry electrode fabrication apparatus for improving film uniformity, characterized in that, include: A-side film forming device and B-side film forming device; both the A-side film forming device and the B-side film forming device include a first diameter support roller and a second diameter roller, wherein the diameter of the first diameter support roller is larger than the diameter of the second diameter roller; The first diameter support roller includes a left force-bearing support roller and a right force-bearing support roller; The second diameter roll comprises, in sequence, a film-forming roll, a first thinning roll, a second thinning roll, a fixed roll, and a composite roll; the fixed roll is a fixed, non-rotating roll, and the film-forming roll, the first thinning roll, the second thinning roll, and the composite roll are all rotating rolls; The line connecting the axis of the second thinning roller to the axis of the first thinning roller and the fixed roller forms an acute angle.

2. The dry electrode fabrication apparatus for improving film uniformity according to claim 1, characterized in that: The diameter of the first diameter support roller is 1.5 to 2.5 times the diameter of the second diameter roller.

3. The dry electrode fabrication apparatus for improving film uniformity according to claim 1, characterized in that: The diameter of the first diameter support roller is 600~900mm; the width of the second diameter roller is 600~1000mm.

4. The dry electrode fabrication apparatus for improving film uniformity according to claim 1, characterized in that: In the A-side film forming apparatus, the second diameter rollers from left to right are: A-side film forming roller, A-side first thinning roller, A-side second thinning roller, A-side fixing roller, and A-side composite roller; the left side of the A-side film forming roller is pressed by the first left force-bearing support roller, and the right side of the A-side composite roller is pressed by the first right force-bearing support roller. In the B-side film forming apparatus, the second diameter rollers from left to right are: B-side composite roller, B-side fixed roller, B-side second thinning roller, B-side first thinning roller, and B-side film forming roller; the left side of the B-side composite roller is pressed by the second left force-bearing support roller, and the right side of the B-side film forming roller is pressed by the second right force-bearing support roller.

5. The dry electrode fabrication apparatus for improving film uniformity according to claim 4, characterized in that: An A-side loading bin is provided above the A-side film-forming roller and the A-side first thinning roller, and a B-side loading bin is provided above the B-side film-forming roller and the B-side first thinning roller.

6. The dry electrode fabrication apparatus for improving film uniformity according to claim 4, characterized in that: The area between the A-side fixed roller and the A-side composite roller is the film exit position of the A-side film forming device, and the area between the B-side composite roller and the B-side fixed roller is the film exit position of the B-side film forming device.

7. The dry electrode fabrication apparatus for improving film uniformity according to claim 6, characterized in that: A first film detection device is provided on the outside of the film exit position of the A-side film forming device, and a second film detection device is provided on the outside of the film exit position of the B-side film forming device.

8. The dry electrode fabrication apparatus for improving film uniformity according to claim 1, characterized in that: The angle between the second thinning roller and the axis connecting the first thinning roller and the fixed roller is 10°~45°.

9. The dry electrode fabrication apparatus for improving film uniformity according to claim 7, characterized in that: It also includes a current collector unwinding mechanism and a dry electrode winding mechanism. The current collector unwinding mechanism is used to unwind the current collector to form a dry electrode with composite front and back films through the B-side film forming device and the A-side film forming device. The dry electrode winding mechanism is used to wind up the obtained dry electrode.

10. The dry electrode fabrication apparatus for improving film uniformity according to claim 1, characterized in that: The bottom of the fixed roller is equipped with a cutting mechanism.

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