A lithium battery coating defect elimination device and elimination method

Abstract

The application provides a lithium battery coating defect elimination device and method, which comprises a coating unit and an oven, and further comprises a defect detection device and a defect treatment device arranged in the oven in sequence along the transmission direction of the pole piece; the defect detection device is used for acquiring image information and position information of the surface defect of the pole piece; the defect treatment device comprises a translation assembly and a material supplement assembly arranged on the translation assembly, and the translation assembly and the material supplement assembly are electrically connected with the defect detection device; the translation assembly is used for driving the material supplement assembly to move above the surface defect point of the pole piece according to the position information of the pole piece defect; and the material supplement assembly is used for supplementing the surface defect point of the pole piece according to the image information of the surface defect of the pole piece. The application can detect the defect of the pole piece before drying, supplement the material at the defect point through the material supplement assembly, eliminate the surface defect of the pole piece, improve the surface quality of the pole piece after drying, and improve the electrical performance of the pole piece after coating and drying.

Description

Technical Field

[0001] This invention relates to the field of lithium battery production technology, and in particular to a device and method for eliminating coating defects in lithium batteries. Background Technology

[0002] Currently, lithium-ion batteries are pursuing high capacity and high rate performance. With the explosive growth of the lithium-ion battery market, overall production capacity pressure is also very high, requiring the production of high-quality lithium-ion batteries at high efficiency. Because bubbles and particles are easily generated in the slurry during production and transportation, after being transferred to the coating process and dried in the oven, issues such as metal leakage, decarburization, bubbles, bright spots, and black spots can easily occur on the surface. These abnormalities often appear as circular pits after the electrode sheets are dried. To address this, methods such as extending the defoaming time of the slurry, increasing the defoaming vacuum, and increasing the filtration capacity of the coating pipeline are used to reduce the occurrence of these abnormalities.

[0003] However, the aforementioned methods in the existing technology still have many problems. Extending the defoaming time of the slurry and increasing the defoaming vacuum cannot completely eliminate bubbles, and they also inadvertently prolong production efficiency. Increasing the filtration capacity can remove a small portion of incompletely dispersed particles, but excessive filtration capacity will increase the internal pressure of the pipeline, making the coating pressure unstable and causing uncontrollable fluctuations in areal density. In addition, patent CN107507956A discloses a lithium-ion battery slurry coating process that controls the surface tension of the aqueous slurry to reduce the phenomenon of depressions. Although this method can reduce the occurrence of surface depressions after electrode coating and drying to a certain extent, its slurry preparation process is complex, and the overall production cost remains high.

[0004] Currently, existing technologies and related patents mostly employ methods that control the slurry coating process to reduce the occurrence of surface depressions after electrode coating. However, this method is limited by the high requirements for process control and cannot minimize the occurrence of defects. In addition, when defects appear on the electrode surface during the coating process, they cannot be eliminated, leading to a decrease in electrode production yield. Summary of the Invention

[0005] In view of this, the present invention proposes a lithium battery coating defect elimination device and method, which can eliminate surface defects of electrode sheets during the lithium battery coating process, thereby improving the yield and electrical performance of the electrode sheets.

[0006] The technical solution of this invention is implemented as follows:

[0007] On one hand, the present invention provides a lithium battery coating defect elimination device, including a coating unit and an oven. The coating unit is used to coat the electrode sheet, and the oven is used to dry the electrode sheet from the coating unit. It also includes a defect detection device and a defect processing device arranged sequentially in the oven along the electrode sheet conveying direction.

[0008] The defect detection device is used to acquire image information and location information of defects on the electrode surface;

[0009] The defect handling device includes a translation component and a feeding component disposed on the translation component. Both the translation component and the feeding component are electrically connected to the defect detection device. The translation component is used to drive the feeding component to move above the defect point on the electrode surface according to the electrode defect location information. The feeding component is used to feed the defect point on the electrode surface according to the electrode surface defect image information.

[0010] Based on the above technical solution, preferably, the translation component includes a first linear module, a connecting plate, and a second linear module;

[0011] The first linear module is horizontally fixed outside the oven along the electrode conveying direction, and a through groove parallel to the first linear module is opened on the side wall of the oven above the first linear module.

[0012] One end of the second linear module passes horizontally through the through slot and extends into the oven. The other end of the second linear module is fixedly connected to the moving end of the first linear module through a connecting plate. The translation direction of the second linear module is perpendicular to the electrode transmission direction.

[0013] The feeding component is fixedly mounted on the moving end of the second linear module.

[0014] Further, preferably, the feeding assembly includes a feeding syringe and a storage tank. The upper end of the feeding syringe is fixedly connected to the moving end of the second linear module, and the lower end of the feeding syringe extends vertically downward toward the electrode surface. The storage tank is fixedly mounted on the connecting plate for storing slurry. The storage tank and the feeding syringe are connected by a feeding pipe.

[0015] Based on the above technical solution, preferably, the defect handling device further includes an air blowing assembly for leveling the slurry at the replenishment location. The air blowing assembly includes an installation component, an air blowing syringe, and a sealing component.

[0016] The mounting component is fixedly disposed between the feeding syringe and the moving end of the second linear module, and one end of the mounting component in the horizontal direction has a mounting cavity.

[0017] The air-blowing syringe is coaxially inserted into the feeding syringe, and there is a flow chamber for slurry flow between the air-blowing syringe and the feeding syringe;

[0018] The sealing element is located between the outer wall of the upper end of the air blowing syringe and the inner wall of the feeding syringe;

[0019] The upper end of the air-blowing syringe extends upward and enters the mounting cavity. The upper end of the air-blowing syringe is provided with an air inlet tube for connecting to an air source.

[0020] Furthermore, preferably, the air blowing assembly further includes a lifting device, which is disposed within the mounting component and is used to drive the air blowing syringe to move downward relative to the feeding syringe, so that the bottom end of the air blowing syringe extends out of the bottom end of the feeding syringe and blocks the bottom outlet of the feeding syringe.

[0021] Furthermore, preferably, the lower end of the feeding syringe has a feeding nozzle with a conical structure, the blowing syringe has a blowing nozzle with a conical structure, and a plurality of blowing holes are equally spaced on the outer circumferential surface of the blowing nozzle, the axis of the blowing holes being inclined downward relative to the axis of the blowing syringe.

[0022] Based on the above technical solution, preferably, the defect detection device includes a first CCD image detection module and a controller. The first CCD image detection module is fixedly installed on the top surface of the oven near the coating unit and is used to acquire image information and location information of the defects on the electrode surface. The output end of the first CCD image detection module is electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the defect processing device.

[0023] Based on the above technical solution, preferably, the temperature range of less than 90°C in the front section of the oven is the movement range of the feeding component.

[0024] Based on the above technical solution, preferably, a bellows protective cover is provided in the through grooves on both sides of the second linear module, and an installation plate is fixedly installed on the top of the second linear module. One end of the installation plate is fixedly connected to the connecting plate, and the other end of the installation plate is slidably connected to the inner wall of the oven through a linear guide rail.

[0025] On the other hand, the present invention also discloses a method for eliminating coating defects in lithium batteries, which utilizes the aforementioned lithium battery coating defect elimination device and includes the following steps:

[0026] S1. The coated electrode sheet is horizontally transported into the oven after being coated by the coating unit, and the image information and location information of the defects on the surface of the electrode sheet are obtained by the defect detection device.

[0027] S2. Based on the location information of the electrode defect point, the translation component drives the feeding component to move directly above the electrode defect point. According to the size of the defect point area, the feeding syringe releases a certain amount of slurry to the defect point. Simultaneously, the air blowing syringe blows the slurry level directly above the defect point.

[0028] The present invention has the following advantages over the prior art:

[0029] (1) The lithium battery coating defect elimination device disclosed in this invention can detect the image information and position information of the defect on the surface of the coated electrode through the defect detection device. After the translation component obtains the position information of the electrode defect point, it can drive the feeding component to move horizontally to the defect position point of the electrode. After the translation component obtains the size of the electrode defect, it can drive the feeding component to feed material at the defect point to eliminate the electrode surface defect, improve the surface quality of the electrode after drying, and improve the electrical performance of the electrode after coating and drying.

[0030] (2) By coaxially setting an air-blowing syringe inside the filling syringe, and blowing air into the air-blowing syringe, the gas is blown vertically downward from the bottom of the air-blowing syringe. Thus, air can be blown into the center of the slurry surface at the defect, so that the raised part of the slurry surface is smoothed out to the surrounding area, and the slurry thickness at the defect is not too high.

[0031] (3) By aligning the bottom end of the air-blowing syringe with the bottom end of the feeding syringe, the slurry will be squeezed out from the gap between the bottom end of the air-blowing syringe and the bottom end of the feeding syringe when it flows downward in the flow chamber. The squeezed slurry drips downward in a ring shape. Since the feeding syringe is at a certain height from the electrode surface, the ring-shaped slurry will automatically condense into droplets due to the tension of the droplets during the falling process, and then drip onto the defect on the electrode surface. At this time, the slurry will not adhere to the opening at the bottom end of the air-blowing syringe. This ensures that the gas blown out from the bottom end of the air-blowing syringe does not contain slurry, and that the gas blown vertically downward can flatten the surface of the slurry in all directions.

[0032] (4) The air-blowing syringe is driven to move downward by the lifting device so that the lower end of the air-blowing syringe passes through the bottom end of the liquid-filling syringe. This allows the lower end of the air-blowing syringe to block the opening of the liquid-filling syringe, thereby preventing the slurry in the flow chamber from flowing downward when subjected to mechanical vibration. This makes it convenient to blow air onto the slurry surface by blowing air vertically downward through the air-blowing syringe, so that the slurry at the defective area can maintain a uniform thickness with the surrounding coating after smoothing.

[0033] (5) The air holes set at an angle on the outer periphery of the air nozzle can blow air around the surface of the slurry. Combined with the air blowing at the bottom of the air nozzle, the surface of the slurry can be flexibly spread out in all directions, so that the gas blown out of the air nozzle forms an umbrella-shaped air curtain structure, which improves the smoothing efficiency of the slurry surface and can also avoid the slurry splashing in all directions due to only vertical air blowing.

[0034] (6) The temperature range of less than 90° in the front section of the oven is the moving range of the feeding component. Since the temperature in this area is low, it does not reach the temperature required for slurry curing. Therefore, the surface defects of the electrode can be reliably eliminated in this area to avoid the slurry inside the feeding syringe from being unable to be squeezed out due to curing. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a three-dimensional structural schematic diagram of the lithium battery coating defect elimination device disclosed in this invention.

[0037] Figure 2 This is a three-dimensional structural diagram of the defect handling device disclosed in this invention;

[0038] Figure 3 This is a schematic diagram of the assembly structure of the feeding component and the blowing component disclosed in this invention;

[0039] Figure 4 for Figure 3 Enlarged view of a portion of point A in the middle;

[0040] Figure 5 This is a top view of the lithium battery coating defect elimination device disclosed in this invention;

[0041] Figure 6 for Figure 5 Plan view at point BB;

[0042] Figure 7 for Figure 5 Planar section view at point CC;

[0043] Figure 8 for Figure 6 Enlarged view of a section at point D;

[0044] Figure label:

[0045] S, Electrode; 1, Coating Unit; 2, Oven; 3, Defect Detection Device; 4, Defect Handling Device; 41, Translation Assembly; 42, Feeding Assembly; 411, First Linear Module; 412, Connecting Plate; 413, Second Linear Module; 21, Through Slot; 421, Feeding Syringe; 422, Storage Tank; 43, Air Blowing Assembly; 431, Mounting Component; 432, Air Blowing Syringe; 433, Sealing Component; 4311, Mounting Cavity; 4321, Air Inlet Pipe; Q, Flow Chamber; 434, Lifting Device; 4210, Feeding Nozzle; 4322, Air Blowing Nozzle; 4323, Air Blowing Hole; 31, First CCD Image Detection Module; 32, Controller; 5, Bellows Protective Cover; 414, Mounting Plate; 415, Linear Guide Rail; 6, Second CCD Image Detection Module. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] During the coating process of the electrode sheet, due to the air bubbles and particles in the slurry itself, the coated electrode sheet is prone to metal leakage, decarburization, air bubbles, bright spots, black spots and other abnormalities on the surface during the drying process in the oven. These abnormalities often appear as circular pits after the electrode sheet is dried, resulting in a depression on the surface of the electrode sheet. The surface density of the depression is low, which will lead to poor appearance on the one hand, and on the other hand, the pits on the surface of the electrode sheet will cause uneven electrical properties of the electrode sheet, affecting the overall performance of the battery.

[0048] Existing technologies often reduce surface depressions on electrode sheets by controlling the slurry coating process. However, this method is subject to high process control requirements and cannot minimize defects. Furthermore, when defects appear on the electrode sheet surface during the coating process, they cannot be eliminated, leading to a decrease in electrode sheet production yield.

[0049] To address the aforementioned problems, this embodiment proposes a lithium battery coating defect elimination device, comprising a coating unit 1 and an oven 2, as shown below. Figure 1 As shown, combined with Figure 2 The lithium battery coating defect elimination device includes a coating unit 1 and an oven 2. The coating unit 1 is used to coat the electrode sheets, and the oven 2 is used to dry the electrode sheets from the coating unit 1. The coating unit 1 and the oven 2 involved in this embodiment are prior art, and their working principles will not be described in detail.

[0050] To eliminate surface defects on the electrode sheets during the lithium battery coating process, the lithium battery coating defect elimination device in this embodiment is further equipped with a defect detection device 3 and a defect processing device 4. The defect detection device 3 and the defect processing device 4 are sequentially arranged inside the oven 2 along the electrode sheet transport direction.

[0051] A defect detection device 3 is used to acquire image and location information of defects on the electrode surface. In some preferred embodiments, the defect detection device 3 includes a first CCD image detection module 31 and a controller 32. The first CCD image detection module 31 is fixedly mounted on the top surface of the oven 2 near the coating unit 1, and is used to acquire image and location information of defects on the electrode surface. The output terminal of the first CCD image detection module 31 is electrically connected to the input terminal of the controller 32, and the output terminal of the controller 32 is electrically connected to the defect processing device 4. The first CCD image detection module 31 can collect quality information of the electrode surface, such as metal leakage, decarburization, bubbles, bright spots, and black spots. The detection conditions are: length ≥ 2mm, width ≥ 2mm, and area ≥ 4mm². 2 When any one of the above-mentioned defects such as metal leakage, decarburization, bubbles, bright spots, and black spots meets the judgment conditions, the first CCD image detection module 31 locates the defect point and takes a picture of the defect location, and transmits the above information to the controller 32, which then controls the defect processing device 4 to process the electrode surface defects.

[0052] The defect handling device 4 includes a translation component 41 and a feeding component 42 disposed on the translation component 41. Both the translation component 41 and the feeding component 42 are electrically connected to the defect detection device 3. The translation component 41 is used to drive the feeding component 42 to move above the defect point on the electrode surface according to the electrode defect location information. The feeding component 42 is used to feed the defect point on the electrode surface according to the electrode surface defect image information.

[0053] Using the above technical solution, when the first CCD image detection module 31 detects a defect on the electrode surface that meets the conditions, the translation component 41 drives the feeding component 42 to move to the corresponding defect point to perform the feeding operation.

[0054] Specifically, after the first CCD image detection module 31 acquires the electrode defect point, it sends the defect point coordinates to the translation component 41 via the controller 32. The translation component 41 then drives the feeding component 42 to move horizontally to the defect location on the electrode. Simultaneously, after the first CCD image detection module 31 acquires the electrode defect image, the controller 32 controls the feeding component 42 to extrude a certain amount of slurry to coat the defect based on the area and depth of the defect, thereby eliminating the surface defect of the electrode.

[0055] It is worth noting that the coating material loaded in the feeding component 42 in this embodiment has the same composition as the slurry used in the coating unit 1. This allows for the feeding of materials to the defective points on the electrode surface, so that the feeding material at the defective point is integrated with the surrounding slurry. This ensures that after the electrode is dried, the surface density of the coating at the defective point is consistent with the surface density of the surrounding coating after subsequent rolling.

[0056] The present invention adopts the above-mentioned technical solution. The defect detection device 3 can detect the image information and position information of the defect on the surface of the coated electrode. After the translation component 41 obtains the position information of the defect point of the electrode, it can drive the feeding component 42 to move horizontally to the defect position point of the electrode. After obtaining the size of the defect, the translation component 41 can drive the feeding component 42 to feed material at the defect point to eliminate the surface defect of the electrode, improve the surface quality of the electrode after drying, and improve the electrical performance of the electrode after coating and drying.

[0057] Since the electrode sheets are continuously transported within the oven 2, the feeding component 42 needs to translate along the transport direction of the electrode sheets when feeding the surface defects of the electrode sheets. At the same time, since the electrode sheets have a certain width, the feeding component 42 needs to translate along the width direction of the electrode sheets. Therefore, in order to enable the translation component 41 to translate the feeding component 42 along both the electrode sheet transport direction and the electrode sheet width, this embodiment shows a preferred implementation of the translation component 41.

[0058] For details, please refer to the appendix. Figure 1 and 2 As shown, the translation component 41 includes a first linear module 411, a connecting plate 412, and a second linear module 413.

[0059] The first linear module 411 is horizontally fixed on the outside of the oven 2 along the electrode conveying direction. Placing the first linear module 411 on the outside of the oven 2 can prevent the high temperature inside the oven 2 from damaging the electrical components of the first linear module 411.

[0060] A through slot 21, parallel to the first linear module 411, is provided on the side wall of the oven 2 above the first linear module 411. One end of the second linear module 413 passes horizontally through the through slot 21 and extends into the oven 2. The other end of the second linear module 413 is fixedly connected to the moving end of the first linear module 411 via a connecting plate 412. The translational direction of the second linear module 413 is perpendicular to the electrode transfer direction. This configuration allows the second linear module 413 to pass horizontally through the through slot 21 into the oven 2. The moving end of the first linear module 411 is driven by the connecting plate 412 to translate the second linear module 413 along the length of the through slot 21.

[0061] The feeding component 42 is fixedly mounted on the moving end of the second linear module 413. As such, the second linear module 413 can drive the feeding component 42 to move horizontally along the width direction of the electrode sheet inside the oven 2. When the first linear module 411 drives the second linear module 413 to move horizontally, it can drive the feeding component 42 to move horizontally along the electrode sheet transmission direction.

[0062] In this embodiment, the first linear module 411 and the second linear module 413 are preferably lead screw linear modules. This configuration ensures translational accuracy, allowing the feeding assembly 42 to accurately align with the electrode defect point. When the first linear module 411 and the second linear module 413 are configured as lead screw linear modules, their moving ends are slides. Of course, in some other embodiments, the first linear module 411 and the second linear module 413 can also be selected from pulley transmission mechanisms or other modules capable of linear movement.

[0063] It is worth noting that the translation speed of the first linear module 411 is consistent with the transmission speed of the electrode sheet in the oven 2. Therefore, when the defect detection device 3 detects a defect on the surface of the electrode sheet, the first linear module 411 drives the second linear module 413 and the material feeding assembly to quickly locate the defect point of the electrode sheet. Then, the translation speed of the first linear module 411 will be consistent with the transmission speed of the electrode sheet until the material feeding assembly completes the material feeding operation for the current defect point. Immediately afterwards, the first linear module 411 will drive the second linear module 413 to drive the material feeding assembly 42 to reset so as to carry out the material feeding and elimination operation for the next defect point.

[0064] This embodiment illustrates a preferred implementation of the feeding assembly 42. For details, please refer to the attached document. Figure 3 and 4 As shown, the feeding assembly 42 includes a feeding syringe 421 and a storage tank 422. The upper end of the feeding syringe 421 is fixedly connected to the moving end of the second linear module 413. The lower end of the feeding syringe 421 extends vertically downward toward the electrode surface. The storage tank 422 is fixedly mounted on the connecting plate 412 for storing slurry. The storage tank 422 and the feeding syringe 421 are connected by a feeding pipe. Using the above technical solution, the slurry can be transported to the feeding syringe 421 through the storage tank 422 via the feed pipe. In some embodiments, a suction pump or peristaltic pump can be installed in the storage tank 422 to transport the slurry in the storage tank 422 to the feeding syringe 421. In this embodiment, an inlet connected to the feed pipe is opened on the upper side wall of the feeding syringe 421. After the slurry enters the inner cavity of the feeding syringe 421 through the inlet, it can be discharged from the bottom of the feeding syringe 421. By controlling the slurry delivery speed and flow rate, the volume of slurry discharged can be controlled, thereby satisfying the feeding operation at the electrode defect.

[0065] In this embodiment, the lower end of the feeding syringe 421 has a feeding nozzle 4210 with a conical structure. The diameter of the feeding nozzle 4210 is smaller than the outer diameter of the feeding syringe 421. Therefore, the slurry can be extruded through the feeding nozzle 4210, thereby controlling the amount of slurry extruded more precisely.

[0066] It is worth noting that the vertical distance between the above-mentioned feeding syringe 421 and the electrode surface is 2-4cm. This distance can prevent the slurry from splashing onto other surfaces after it falls vertically into the electrode defect point.

[0067] As the slurry is squeezed from the bottom of the feeding syringe 421 and falls into the electrode defect location, there is tension on the slurry surface. The slurry surface is in a raised state at the depression. As a result, after drying, the thickness of the electrode defect location will be higher than other surfaces, making the electrode thickness at the defect location slightly larger. This makes the overall thickness of the electrode uneven, causing the current carrying capacity at the electrode defect location to be inconsistent with the current carrying capacity at other surfaces, thus affecting the battery's charge and discharge performance.

[0068] Therefore, the defect handling device 4 in this embodiment is also provided with an air blowing assembly 43, as shown in the attached drawing. Figure 3-8 As shown, it is used to level the slurry at the feeding location.

[0069] Specifically, the air blowing assembly 43 includes a mounting part 431, an air blowing syringe 432, and a sealing part 433.

[0070] Mounting component 431 is fixedly disposed between the feeding syringe 421 and the moving end of the second linear module 413. The upper end of the feeding syringe 421 is fixedly connected to the bottom surface of the mounting component 431, and the top surface of the mounting component 431 is fixedly connected to the moving end of the second linear module 413.

[0071] Mounting component 431 has a mounting cavity 4311 at one horizontal end, which is open at one end to facilitate the installation of the lifting device 434 described below.

[0072] The air-blowing syringe 432 is coaxially inserted into the feeding syringe 421. There is a flow chamber Q between the air-blowing syringe 432 and the feeding syringe 421 for the flow of slurry. The slurry is inside the flow chamber Q and can flow out through the gap between the bottom of the feeding syringe 421 and the air-blowing syringe 432 along the flow chamber Q.

[0073] The seal 433 is disposed between the outer wall of the upper end of the air blowing syringe 432 and the inner wall of the feeding syringe 421. This arrangement can prevent the slurry in the flow chamber Q from flowing upward and leaking between the air blowing syringe 432 and the feeding syringe 421. The seal 433 is made of rubber, which provides good sealing performance.

[0074] The upper end of the air-blowing syringe 432 extends upward and enters the mounting cavity 4311. An air inlet pipe 4321 for connecting to an air source is provided at the upper end of the air-blowing syringe 432. With this configuration, an external air source is connected to the air inlet pipe 4321 via an air guide pipe, thereby blowing air into the air-blowing syringe 432. The gas is blown vertically downward from the bottom end of the air-blowing syringe 432. This allows air to be blown onto the center of the slurry surface at the defect location, smoothing out any protruding parts of the slurry surface and preventing excessive slurry thickness at the defect location.

[0075] In some embodiments, in the initial state, the bottom end of the air-blowing syringe 432 is higher than the bottom end of the feeding syringe 421, so that the slurry in the flow chamber Q flows downward to the bottom end of the air-blowing syringe 432 and is squeezed out from the opening at the bottom end of the feeding syringe 421, so that the slurry flows out of the opening at the bottom end of the feeding syringe 421 in the form of droplets.

[0076] In the above embodiment, since the slurry flows along the flow chamber Q to the bottom of the blowing syringe 432 and then flows out from the opening at the bottom of the feeding syringe 421, the blowing syringe 432 will blow the slurry adhering to the bottom of the blowing syringe 432 to the surface of the slurry during the blowing process. This will increase the volume of the slurry at the defect location, causing more slurry at the defect location to overflow to the surrounding area. After blowing through the blowing syringe 432, there will be a phenomenon of excessive slurry thickness around the electrode defect location, which affects the appearance and also affects the electrode flow capacity.

[0077] Therefore, a preferred solution in this embodiment is to align the bottom ends of the air-blowing syringe 432 and the feeding syringe 421. With this arrangement, when the slurry flows downward in the flow chamber Q, it will be squeezed out from the gap between the bottom ends of the air-blowing syringe 432 and the feeding syringe 421. The squeezed slurry drips downward in a ring shape. Since the feeding syringe 421 is at a certain height from the electrode surface, the ring-shaped slurry will automatically agglomerate into a droplet shape due to the tension of the droplets during the falling process, and thus drip onto the defective area on the electrode surface. At this time, the slurry will not adhere to the opening at the bottom end of the air-blowing syringe 432. This ensures that the gas blown out from the bottom end of the air-blowing syringe 432 is not mixed with slurry, and that the gas blown vertically downward can flatten the slurry surface in all directions.

[0078] After the feeding component 42 is completed, it will move along with the first linear module 411. Due to the influence of mechanical movement, the slurry between the bottom end of the air blowing syringe 432 and the bottom end of the feeding syringe 421 will be vibrated and fall onto the electrode surface, resulting in excessive slurry thickness on the electrode surface. Therefore, the following technical solution is adopted in this embodiment to solve the problem.

[0079] Specifically, the air blowing assembly 43 also includes a lifting device 434, which is disposed within the mounting component 431. The lifting device 434 drives the air blowing syringe 432 downward relative to the replenishing syringe 421, so that the bottom end of the air blowing syringe 432 extends beyond the bottom end of the replenishing syringe 421 and seals the bottom outlet of the replenishing syringe 421. Using the above technical solution, after the replenishing syringe 421 has replenished the electrode defect, the lifting device 434 drives the air blowing syringe 432 downward, allowing its lower end to pass through the bottom end of the replenishing syringe. This seals the opening of the replenishing syringe through the lower end of the air blowing syringe 432, preventing the slurry in the flow chamber Q from flowing downward when subjected to mechanical vibration. This facilitates surface blowing of the slurry using only the air blowing syringe 432, achieving a smoothing operation of the slurry surface and ensuring that the slurry at the defect is smoothed and maintains a uniform thickness with the surrounding coating.

[0080] In this embodiment, the air-blowing syringe 432 has a conical air-blowing nozzle 4322, which is fitted inside the feeding nozzle 4210. The bottom end of the air-blowing nozzle 4322 is flush with the bottom end of the feeding nozzle 4210. A gap of 0.1mm-1mm is provided between the air-blowing nozzle 4322 and the feeding nozzle 4210 for slurry supply. When the lifting device 434 drives the air-blowing syringe 432 to move downward relative to the feeding syringe 421, the air-blowing nozzle 4322 extends out of the bottom end of the feeding nozzle 4210. The outer surface of the air-blowing nozzle 4322 and the inner surface of the feeding nozzle 4210 abut against each other, thereby sealing the bottom opening of the feeding syringe 421. It is worth noting that because the gap between the air-blowing nozzle 4322 and the feeding nozzle 4210 is small, the amount of slurry squeezed out in the gap during the sealing process is small and can be ignored.

[0081] As a preferred embodiment, the lifting device 434 in this embodiment is preferably a push-pull electromagnet. This structure can be used in a small space of the mounting cavity 4311, and at the same time, this structure is not affected by the temperature of the oven 2.

[0082] Based on the above technical solution, the air blown vertically downwards from the bottom opening of the air-blowing syringe 432 can easily cause the slurry surface to become concave and splash, making it difficult to control the smoothing of the slurry surface. Therefore, in this embodiment, a plurality of air-blowing holes 4323 are evenly spaced on the outer peripheral surface of the air-blowing nozzle 4322, and the axis of the air-blowing holes 4323 is inclined downwards relative to the axis of the air-blowing syringe 432. With this configuration, the air-blowing holes 4323 inclined on the outer peripheral surface of the air-blowing nozzle 4322 can blow air around the slurry surface. Combined with the air blowing from the bottom of the air-blowing nozzle 4322, the slurry surface can be flexibly spread outwards, so that the gas blown out by the air-blowing nozzle 4322 forms an umbrella-shaped air curtain structure, improving the smoothing efficiency of the slurry surface and avoiding the slurry splashing outwards due to only vertical air blowing.

[0083] Since the slurry needs a certain temperature to solidify, the temperature in the front section of the oven 2 is lower and the temperature is higher in the later section during the drying process. If the feeding component 42 moves to the rear section of the oven 2, the slurry in the feeding syringe 421 may solidify due to the excessive temperature of the oven 2, making it impossible to extrude and causing feeding failure.

[0084] Therefore, in this embodiment, the temperature range of less than 90°C in the front section of the oven 2 is the moving range of the feeding component 42. Since the temperature in this area is lower, it does not reach the temperature required for slurry curing. Therefore, in this area, the surface defects of the electrode can be reliably eliminated, and the slurry inside the feeding syringe cannot be squeezed out due to curing.

[0085] As some other implementations, accordion covers 5 are respectively provided in the through slots 21 on both sides of the second linear module 413. With this configuration, when the second linear module 413 moves in the through slots 21, the accordion covers 5 can be horizontally pulled, so that the flexible through slots 21 of the accordion covers 5 can be used to block the internal temperature of the oven 2, preventing the internal temperature of the oven 2 from leaking through the through slots 21 and ensuring that the internal temperature of the oven 2 is at a suitable level.

[0086] Since the second linear module 413 is horizontally positioned inside the oven 2, to ensure smoother and more stable translation of the second linear module 413, this embodiment includes a mounting plate 414 fixedly installed above the second linear module 413. One end of the mounting plate 414 is fixedly connected to the connecting plate 412, and the other end of the mounting plate 414 is slidably connected to the inner wall of the oven 2 via a linear guide rail 415. This configuration creates an L-shaped structure where one end of the overall structure is connected to the translation end of the first linear module 411, and the other end is slidably connected within the oven 2 via the linear guide rail 415, thus ensuring smooth and reliable translation of the second linear module 413 inside the oven 2.

[0087] As one of the other implementations, the oven 2 is also equipped with a second CCD image detection module 6, which is used to re-photograph and detect the defective parts of the electrode sheet to confirm whether the defective position is well filled. If the filling is not good, the position is marked and then marked in the subsequent production process.

[0088] This invention also discloses a method for eliminating coating defects in lithium batteries, which utilizes the aforementioned lithium battery coating defect elimination device and includes the following steps:

[0089] S1. The electrode sheet coated by the coating unit 1 is horizontally transported into the oven 2, and the image information and location information of the defect on the surface of the electrode sheet are obtained by the defect detection device 3.

[0090] S2. Based on the location information of the electrode defect point, the translation component 41 drives the feeding component 42 to move directly above the electrode defect point. According to the size of the defect point area, the feeding syringe 421 releases a certain amount of slurry to the defect point. Simultaneously, the blowing syringe 432 blows the slurry flat directly above the defect point.

[0091] Specifically, after the first CCD image detection module 31 acquires the electrode defect point, it sends the defect point coordinates to the translation component 41 via the controller 32. The translation component 41 then drives the feeding component 42 to move horizontally to the defect location on the electrode. Simultaneously, after the first CCD image detection module 31 acquires the electrode defect image, the controller 32 controls the feeding component 42 to extrude a certain amount of slurry and coat it onto the defect based on the area and depth of the defect. Then, the air blowing component 43 blows air vertically downwards to flatten the slurry surface at the electrode defect, making the slurry surface at the defect as flush as possible with the surrounding surface.

[0092] As some examples, when the defect meets the following conditions: length 2-3mm, width 2-3mm, area 4-5mm² 2 At any point, the feeding syringe 421 squeezes out 1.5ml of slurry to the defect location, and the blowing syringe 432 applies an air velocity of 3-4m / s for 3-5s to level the feeding location; when the defect length is >3mm, width is >3mm, and area is >9mm². 2 When any defect is met, squeeze out 2-3 ml of slurry to the defect location and then apply a 6-7 m / s wind speed for 4-6 seconds to level the filling location.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium battery coating defect elimination device, comprising a coating unit (1) and an oven (2), wherein the coating unit (1) is used for coating electrode sheets, and the oven (2) is used for drying the electrode sheets from the coating unit (1), characterized in that: It also includes a defect detection device (3) and a defect processing device (4) arranged sequentially in the oven (2) along the electrode conveying direction; The defect detection device (3) is used to acquire image information and location information of defects on the surface of the electrode sheet; The defect handling device (4) includes a translation component (41) and a feeding component (42) disposed on the translation component (41). Both the translation component (41) and the feeding component (42) are electrically connected to the defect detection device (3). The translation component (41) is used to drive the feeding component (42) to move above the defect point on the electrode surface according to the electrode defect location information. The feeding component (42) is used to feed the defect point on the electrode surface according to the electrode surface defect image information. The temperature area below 90°C in the front section of the oven (2) is the moving range of the feeding component (42). The translation component (41) includes a first linear module (411), a connecting plate (412), and a second linear module (413); The first linear module (411) is horizontally fixed outside the oven (2) along the electrode conveying direction. A through groove (21) parallel to the first linear module (411) is opened on the side wall of the oven (2) above the first linear module (411). One end of the second linear module (413) passes horizontally through the through slot (21) and extends into the oven (2). The other end of the second linear module (413) is fixedly connected to the moving end of the first linear module (411) through the connecting plate (412). The translation direction of the second linear module (413) is perpendicular to the electrode transmission direction. The feeding assembly (42) is fixedly mounted on the moving end of the second linear module (413); The feeding assembly (42) includes a feeding syringe (421) and a storage tank (422). The upper end of the feeding syringe (421) is fixedly connected to the moving end of the second linear module (413). The lower end of the feeding syringe (421) extends vertically downward toward the electrode surface. The storage tank (422) is fixedly mounted on the connecting plate (412) for storing slurry. The storage tank (422) and the feeding syringe (421) are connected by a feeding pipe. The defect handling device (4) further includes an air blowing assembly (43) for leveling the slurry at the feeding position. The air blowing assembly (43) includes a mounting part (431), an air blowing syringe (432), and a sealing part (433). The mounting component (431) is fixedly disposed between the feeding syringe (421) and the moving end of the second linear module (413), and the mounting component (431) has a mounting cavity (4311) at one end in the horizontal direction; An air-blowing syringe (432) is coaxially inserted into a feeding syringe (421), and there is a flow chamber (Q) between the air-blowing syringe (432) and the feeding syringe (421) for supplying slurry flow; The sealing element (433) is disposed between the outer wall of the upper end of the air blowing syringe (432) and the inner wall of the feeding syringe (421); The upper end of the blowing syringe (432) extends upward and enters the mounting cavity (4311). The upper end of the blowing syringe (432) is provided with an air inlet pipe (4321) for connecting to an air source. The blowing assembly (43) also includes a lifting device (434), which is disposed in the mounting component (431) and is used to drive the blowing syringe (432) to move downward relative to the feeding syringe (421) so that the bottom end of the blowing syringe (432) extends out of the bottom end of the feeding syringe (421) and blocks the bottom outlet of the feeding syringe (421); The lower end of the feeding syringe (421) has a feeding nozzle (4210) with a conical structure, and the blowing syringe (432) has a blowing nozzle (4322) with a conical structure. A plurality of blowing holes (4323) are evenly spaced on the outer circumferential surface of the blowing nozzle (4322), and the axis of the blowing holes (4323) is inclined downward relative to the axis of the blowing syringe (432).

2. The lithium battery coating defect elimination device as described in claim 1, characterized in that: The defect detection device (3) includes a first CCD image detection module (31) and a controller (32). The first CCD image detection module (31) is fixedly installed on the top surface of the oven (2) near the coating unit (1) to acquire image information and location information of the defects on the electrode surface. The output end of the first CCD image detection module (31) is electrically connected to the input end of the controller (32), and the output end of the controller (32) is electrically connected to the defect processing device (4).

3. The lithium battery coating defect elimination device as described in claim 1, characterized in that: The second linear module (413) is provided with bellows protective covers (5) in the through slots (21) on both sides. The second linear module (413) is fixedly provided with a mounting plate (414). One end of the mounting plate (414) is fixedly connected to the connecting plate (412), and the other end of the mounting plate (414) is slidably connected to the inner wall of the oven (2) through a linear guide rail (415).

4. A method for eliminating coating defects in lithium batteries, which utilizes the lithium battery coating defect elimination device as described in any one of claims 1-3, characterized in that, The steps include the following: S1. The coated electrode sheet is horizontally transported to the oven (2) after being coated by the coating unit (1), and the image information and location information of the defect on the surface of the electrode sheet are obtained by the defect detection device (3). S2. Based on the location information of the electrode defect point, the translation component (41) drives the feeding component (42) to move directly above the electrode defect point. According to the size of the defect point area, the feeding syringe (421) releases a certain amount of slurry to the defect point. Simultaneously, the blowing syringe (432) blows the slurry flat directly above the defect point.

Images