Slit type coating die head for preparing micro-structure battery pole piece

Abstract

The invention relates to the technical field of battery pole piece coating, in particular to a slit type coating die head for preparing a micro-structure battery pole piece, which comprises a coating die head for coating a current collector with slurry and a feeding device connected with the coating die head in a penetrating manner and used for providing the slurry for the coating die head, the coating die head comprises an upper die head, a coating limiting gasket and a lower die head which are fixedly arranged in an overlapped mode, a microstructure gasket used for conducting microstructure coating on a current collector is further arranged between the coating limiting gasket and the upper die head, and a microstructure flow channel used for discharging slurry is further formed in the side, close to the coating limiting gasket, of the microstructure gasket. Compared with the prior art that the slurry is firstly coated and then the microstructure coating is formed on the slurry through a laser etching method or a template method, the process steps of slurry coating are reduced, coating of the microstructure can be synchronously completed in the conventional slurry base layer coating process, and equipment is easy to operate and convenient to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of microstructure battery pole piece coating, and in particular to a slit-type coating die head for coating battery pole pieces to prepare microstructure battery pole pieces. Background Art

[0002] The battery pole piece is one of the core components of the battery, which mainly includes a metal current collector and a slurry fixed on the surface of the metal current collector after coating. The design of its structure and the characteristics of the slurry will directly affect the electrochemical reaction, energy density, and cycle life of the battery, and then affect the performance, stability and application range of the battery. Specifically, first, the structure of the battery pole piece can affect the efficiency of the electrochemical reaction inside the battery. For example, in lithium-ion batteries, the reasonable design of the electrode structure can provide larger electron and ion conduction channels, thereby improving the charge and discharge rate and efficiency of the battery. Secondly, the structure of the battery pole piece can affect the energy density of the battery, that is, the energy stored per unit volume or mass. The optimized pole piece structure can accommodate more active materials, thereby improving the energy storage capacity of the battery. Thirdly, the structure and material selection of the battery pole piece can also affect the cycle life of the battery. A reasonable pole piece structure will reduce the expansion and contraction of the electrode material, thereby reducing the loss of the electrode material and extending the service life of the battery. Finally, the optimized pole piece structure can provide a larger surface area and better conductivity, allowing the battery to charge and discharge faster, which is very important for applications that require fast charging. In summary, the design and optimization of battery pole piece structure is a key factor that cannot be ignored in the process of battery R&D and manufacturing. A reasonable pole piece structure can improve battery performance while meeting different application requirements and help promote further innovation and development of battery technology.

[0003] Microstructured battery pole pieces are specially designed battery pole pieces with tiny size and specific shape, which can optimize the electronic conductivity, ion diffusion performance and reaction activity of the battery, thereby improving the performance and function of the battery. The design and optimization of the microstructure of the battery pole piece can bring many advantages to the battery, such as: the microstructure can increase the surface area of ​​the battery pole piece, promote better contact between the active material and the electrolyte, thereby improving the electrochemical reaction efficiency and energy density; the microstructure can increase the reaction rate of the battery, so that the battery can be charged and discharged faster, which is suitable for applications with high power output requirements; the microstructure provides a faster electron conduction channel, reduces resistance, thereby reducing internal energy loss in the battery and improving battery performance; the microstructure provides more ion channels, accelerates the diffusion of electrolytes in the battery, thereby increasing the charge and discharge rate of the battery; the optimized microstructure can reduce the expansion, loss and mechanical stress of the electrode material, which helps to improve the cycle life of the battery.

[0004] The so-called coating refers to the process of evenly coating the lithium-ion battery slurry on the surface of the metal current collector to form a microstructured battery pole piece. According to incomplete statistics, in the battery manufacturing process, battery failures caused by the metal current collector coating process account for more than 10% of all lithium battery failures caused by all reasons. It can be seen that the coating of lithium-ion battery slurry on the metal current collector is a very critical technology, which will directly affect the overall performance, efficiency and life of the battery pole piece. At present, the following two preparation methods are mainly used for the production of microstructured battery pole pieces: Laser etching method, the so-called laser etching method refers to the directional etching of a metal current collector uniformly coated with a layer of lithium-ion battery slurry by a laser beam, so that a corresponding concave-convex structure is formed in the lithium-ion battery slurry on the surface of the metal current collector to obtain a microstructure coating. This preparation method makes full use of the high energy of the laser beam, and can heat the surface of the lithium-ion battery slurry in a short time to melt, evaporate or peel it. Specifically, when the lithium-ion battery slurry is irradiated by the laser beam, the molecules on its surface will be activated to form a local area of ​​high temperature and high pressure, which will cause it to undergo physical or chemical changes. These changes will cause it to evaporate, burn, dissolve and other processes, thereby forming a tiny structure. Its advantages are: high precision, high-resolution and high-precision processing can be achieved, and it is suitable for the production of fine patterns and structures; high quality, this method adopts non-contact processing, so the laser does not directly contact the material during the processing process, which can avoid physical damage; high controllability, adjusting the laser parameters can accurately control the processing depth, morphology, etc.; wide adaptability, suitable for a variety of materials, and can produce different types of microstructures. Its disadvantages are: there is a thermal effect. Laser etching may cause local heating of lithium-ion battery slurry, produce a heat-affected zone, and ultimately affect the performance of lithium-ion battery slurry; the processing speed is slow. For some materials, the processing speed is relatively slow and it takes a long time to complete the processing; professional laser equipment and technology are required, and the processing cost is relatively high. In addition, this technology can only perform subtractive manufacturing, which will generate processing dust, causing battery pole piece contamination, requiring post-cleaning treatment, and causing certain quality risks.

[0005] Template method, the preparation of microstructured battery pole pieces by template method mainly includes the following steps: template selection, select a template with the required microstructure. Template coating, place the template on a metal current collector coated with a layer of lithium-ion battery slurry, and ensure that the template is in contact with the surface of the lithium-ion battery slurry. Then, apply the lithium-ion battery slurry again to fill the concave and convex structure of the template. Compacting and post-processing, according to the properties of the lithium-ion battery slurry, appropriate pressure, temperature or chemical treatment can be applied to make the lithium-ion battery slurry fill the microstructure of the template. Separation of template, when the lithium-ion battery slurry is solidified or filled, the template needs to be separated from its surface. During the template separation process, the microstructure of the template will be transferred to the electrode material to form the required microstructure and obtain a microstructured battery pole piece. The advantage of this method for preparing microstructured battery pole pieces is that the structure of the template can be designed according to the requirements of the battery pole piece, such as micropores, microgrooves, etc.; and by selecting different templates and adjusting the preparation parameters, the geometric shape, size and distribution of the microstructure can be precisely controlled. However, this preparation method also has some fatal shortcomings: when separating the template, the microstructure will inevitably be damaged to a certain extent, so the consistency between the microstructures may be affected, so the performance of the microstructure battery electrode is often difficult to meet the ideal expectations; the battery electrode production efficiency is low and mass production is not possible.

[0006] At present, the improvement of the overall performance of battery electrodes is in line with the needs of battery development. Therefore, microstructured battery electrodes have become a hot spot in battery electrode research and application. However, the two preparation processes of microstructured battery electrodes mentioned above - laser etching method or template method are difficult to meet the market demand for microstructured battery electrodes, and the overall preparation time is too long, the preparation cost is high, and it is difficult to achieve rapid and mass production of microstructured battery electrodes. Summary of the invention

[0007] The present invention provides a slit coating die head for rapid and mass production of microstructured battery pole pieces, which is specifically achieved through the following technical solutions: A slit-type coating die comprises a coating die for coating a current collector with a slurry, and a feeding device which is connected to the coating die and is used to provide the coating die with slurry. The coating die comprises an upper die, a coating limit gasket, and a lower die which are fixedly arranged in a stacked manner. A microstructure gasket for microstructure coating of the current collector is also provided between the coating limit gasket and the upper die. The microstructure gasket is also provided with a microstructure flow channel for discharging the slurry on the side close to the coating limit gasket.

[0008] The present invention can form a discharge slit structure with a microstructure between the microstructure gasket, the coating limit gasket, and the lower die head by arranging a microstructure gasket between the coating limit gasket and the upper die head, and arranging a microstructure flow channel on the microstructure gasket. Therefore, compared with the technology of first coating the slurry and then forming a microstructure coating on the slurry by laser etching or template method in the prior art, the present invention reduces the process steps of slurry coating, and can simultaneously complete the microstructure coating during the conventional slurry base coating process. The equipment is simple to operate and easy to implement, and can be used for the efficient production of microstructure battery pole pieces, providing a new method and idea for the preparation of microstructure battery pole pieces. Specifically, while the feeding device of the present invention continuously provides slurry to the coating die head, the slurry in the coating die head will flow out along the discharge slit structure, so after the coating step, a coating corresponding to the shape of the discharge slit structure will be formed on the surface of the current collector.

[0009] The microstructured flow channel includes a plurality of grooves equidistantly arranged on one side of the microstructured gasket close to the coating limiting gasket. Therefore, after coating, a plurality of microstructured coatings protruding from the surface of the slurry base layer and arranged at intervals will be formed on the surface of the slurry base layer.

[0010] Preferably, the lower die head is formed with a plurality of equally spaced diversion units along the length direction, one end of the diversion unit is connected to a feeding device, and the end of the diversion unit away from the feeding device is provided with a feeding cavity connecting a plurality of diversion units, and the feeding cavity is connected to the microstructure flow channel.

[0011] The characteristic of the slit coating die is that it requires continuous feeding pressure from the feeding device to squeeze out the slurry stored in the discharge slit structure, so that the slurry is coated on the surface of the metal current collector to form a slurry coating. However, in the process of using the microstructure flow channel to coat the slurry, due to the small structure of the microstructure flow channel itself, it is difficult to evenly fill multiple microstructure flow channels in the length direction of the coating die with slurry, which will inevitably cause the technical problem of unsatisfactory uniformity of multiple microstructure coatings on the surface of the slurry base. Based on this, this technical solution forms a number of equally spaced diversion units on the lower die along the length direction, so that the coating die can be fed evenly along the length direction, and then the multiple diversion units connected to the length direction of the feed cavity will evenly feed the feed cavity. At this time, the slurry in the feed cavity will also be evenly pressed into the discharge slit structure and fill the entire microstructure flow channel. Therefore, after coating, a microstructure coating with high uniformity will be formed on the surface of the slurry base.

[0012] As a further preference, the microstructure gasket is further provided with a material transfer cavity which is through-connected with the microstructure flow channel, and the material transfer cavity is arranged corresponding to the material supply cavity.

[0013] In principle, the coating of the microstructure can be achieved by setting a microstructure flow channel for discharging slurry on the microstructure gasket. However, in this technical solution, by setting a transfer cavity, the transfer effect when the feed cavity directly provides slurry to the microstructure flow channel can be further optimized, so the consistency of the microstructure coating obtained after coating will be higher. Specifically, by setting a transfer cavity corresponding to the feed cavity, part of the slurry in the feed cavity will flow into the transfer cavity under the extrusion of the feeding device, and accumulate in the transfer cavity. Part of the accumulated slurry will flow out along the microstructure flow channel to form a microstructure coating, and the other part will remain in the transfer cavity to provide a guarantee for the stable discharge of the microstructure flow channel.

[0014] As a further preference, the coating die head further comprises a pressure sensor for measuring the pressure of the slurry in the feed cavity corresponding to the diversion unit.

[0015] The stability of coating slurry discharge is mainly related to the pressure in the feed chamber. In order to further optimize the uniformity of slurry filling in multiple microstructure flow channels, this technical solution, on the basis of setting up a diversion unit, also equips multiple diversion units with corresponding pressure sensors respectively, so that the slurry pressure in the feed chamber corresponding to each diversion unit can be measured. Therefore, by controlling the feed pressure of the feeding device connected to the diversion unit, the slurry pressure in the feed chamber along the length direction can be unified, which means that the slurry filling in the microstructure flow channel will be more uniform, and the uniformity between the formed microstructure coatings will be higher.

[0016] As a further preference, the feeding device comprises a feeding diversion pipeline connected to the diversion unit, and the feeding diversion pipeline is also provided with a proportional flow valve for controlling the flow rate of the slurry flowing into the diversion unit, and the proportional flow valve is electrically connected to the pressure sensor.

[0017] This technical solution can more flexibly and accurately adjust the pressure of the slurry in the feed chamber dynamically by setting up multiple feed diversion pipelines that match multiple diversion units, and connecting the pressure sensor that measures the slurry pressure in the feed chamber with the proportional flow valve used to control the flow rate of the slurry flowing from the feed diversion pipeline into the diversion unit, and further ensure the uniformity of the slurry pressure in the feed chamber along the length direction. Specifically, multiple pressure sensors test the slurry pressure in the feed chamber corresponding to multiple diversion units respectively to obtain multiple groups of pressure values. In order to keep the slurry pressure uniform along the length direction of the feed chamber, the present invention can analyze the multiple groups of pressure values ​​and adjust the multiple proportional flow valves connected to the diversion units in whole or in part accordingly, so as to reduce the difference in slurry pressure at different positions in the feed chamber and achieve uniform slurry pressure.

[0018] As a further preference, the feeding device also includes a quick-connect chuck and a feeding diverter block connected to the quick-connect chuck; the feeding diverter block includes a main pipeline and sealing plugs arranged at both ends of the main pipeline; the main pipeline is also provided with a diverter hole for connecting the feeding diverter pipeline.

[0019] At present, the slurry used to coat the current collector mainly includes active materials, binders, conductive agents, etc., which are non-Newtonian fluids. Based on its functional requirements, the slurry itself needs to have a certain viscosity so that the slurry can be more firmly attached to the surface of the current collector after drying. The feed diverter block is a slurry feeding pipeline with a certain viscosity. Its convenience of disassembly will directly affect its service life and cleaning difficulty. Therefore, this technical solution sets sealing plugs that can be easily disassembled at both ends of its main pipeline, which is convenient for quick cleaning of the main pipeline and has high practicality.

[0020] Application of any of the above-mentioned slot coating dies in current collector coating.

[0021] Compared with the prior art, the slit coating die of the present invention reduces the process steps of slurry coating when coating the current collector, and can simultaneously complete the coating of the microstructure during the conventional slurry base coating process. The equipment is simple to operate and easy to implement, which meets the current development needs of microstructure battery electrodes.

[0022] Preferably, the application of any of the above-mentioned slot coating die heads comprises the following steps: S1. The monitoring probe of the pressure sensor collects the pressure data of the slurry in the feeding chamber, and then the communication module of the pressure sensor uploads the pressure data to the controller; S2. The controller analyzes and calculates the pressure data, and controls the flow rate of the slurry flowing into the diversion unit by controlling the proportional flow valve according to the analysis and calculation results.

[0023] The pressure sensor of the present invention can accurately measure the slurry pressure in the feed chamber in real time and dynamically; the controller analyzes and calculates multiple pressure data uploaded by the pressure sensor, and adjusts the corresponding proportional flow valves respectively, so as to reduce the slurry pressure difference in the feed chamber as a whole. Therefore, the slurry pressure in the feed chamber is more consistent, and it is easier to evenly pass through the discharge slit structure to form a slurry coating with better coating effect.

[0024] A microstructured battery electrode produced by any of the above-mentioned slit coating dies.

[0025] Preferably, the current collector of the microstructured battery pole piece is coated with a slurry base layer, and microstructure coatings are equidistantly arranged on the surface of the slurry base layer.

[0026] The present invention can complete the microstructure coating simultaneously during the conventional slurry base coating process by designing a discharge slit structure with a microstructure between the microstructure gasket, the coating limit gasket, and the lower die head. It is worth mentioning that compared with the technical solution of first coating the slurry base and then forming a microstructure coating on the slurry base by laser etching or template method in the prior art, the present invention effectively solves the technical problem of poor connection between the slurry base and the microstructure coating, and the obtained slurry base and microstructure coating have uniform thickness and high microstructure consistency. In addition, the microstructure battery pole piece prepared by the present invention has a larger surface area, can meet the needs of high power output, and has low resistance, and the overall comprehensive performance of the microstructure battery pole piece has been significantly improved.

[0027] Compared with the prior art, the present invention has the following beneficial effects: The present invention forms a microstructured discharge slit structure between the microstructured gasket, the coating limiting gasket, the upper die head, and the lower die head by arranging a microstructured gasket between the coating limiting gasket and the upper die head. Therefore, compared with the prior art, the present invention can simultaneously complete the coating of the microstructure during the coating of the conventional slurry base layer, reducing the coating process steps, and the equipment is simple to operate and easy to implement. It can be used for the efficient production of microstructured battery pole pieces, providing a new method and idea for the coating of microstructured battery pole pieces.

[0028] The present invention configures a plurality of feed shunt pipelines for the same coating die head, so that the coating die head can be fed evenly along the length direction, which solves the problem that the feeding progress at both ends and the middle of the coating die head is difficult to unify due to the traditional coating die head only having one supply pipeline. On this basis, the present invention further provides a proportional flow valve on the feed shunt pipeline to better control the speed at which the slurry in the corresponding feed shunt pipeline flows into the coating die head, and the feeding flexibility and overall controllability are higher.

[0029] The present invention is provided with a pressure sensor matched with a proportional flow valve, which can monitor the pressure in the feed chamber in real time, and upload the obtained pressure data to the controller after monitoring. Then, the controller can reduce the pressure difference of the slurry at different positions in the feed chamber by adjusting the proportional flow valve according to the pressure data, and ensure that the slurry is uniformly squeezed out of the discharge slit structure, and a coating layer is formed after coating. Therefore, through the cooperation of the proportional flow valve, the pressure sensor and the controller, the technical problem of the difficulty in controlling the uniformity of the discharge of the microstructure flow channel can be effectively solved. The slurry base layer and the microstructure coating on the microstructure battery pole piece obtained after coating are more uniform, the microstructure consistency is high, and the overall comprehensive performance of the microstructure battery pole piece is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to clearly illustrate the embodiments, the drawings of the accompanying drawings are briefly introduced below: Figure 1 This is a schematic diagram of the overall assembly of the slot coating die head of Example 1; Figure 2 This is an exploded view of some components of the slot coating die head of Example 1; Figure 3 An exploded view of some components of the coating die head of Example 1; Figure 4 This is a front view of the lower die head of Example 1; Figure 5 It is a side view of the coating die head of Example 1; Figure 6 for Figure 5 A cross-sectional view of the coating die along the marked direction; Figure 7 This is a top view of the feed diverter block of Example 1; Figure 8 for Figure 7 A cross-sectional view of the feed diverter block along the marked direction; Fig. 9 It is a top view of the microstructure gasket structure of Example 1; Fig.10 for Fig. 9 Magnified view of the marked part; Fig.11 for Fig. 9 Side view of the marked section; Fig.12 It is an assembly diagram of a microstructured gasket and a coated limiting gasket; Fig.13 A view of one side of the discharge slit of the coating die head of Example 1; Fig.14 for Fig.13 A magnified view of the part at the marked position; Fig.15 A top view of a microstructured battery electrode sheet prepared using the slot-type coating die of Example 1; Fig.16 for Fig.15 Side view of the microstructured battery electrode; Fig.17 for Fig.16 Magnified view of the marked area.

[0031] Figure numerals: 1. coating die head, 11. upper die head, 12. coating limit gasket, 13. lower die head, 131. diversion unit, 132. feeding chamber, 14. microstructure gasket, 141. material transfer chamber, 142. microstructure flow channel, 15. pressure sensor, 2. feeding device, 21. feeding diversion pipeline, 22. proportional flow valve, 23. quick-connect chuck, 24. feeding diversion block, 241. main pipeline, 242. sealing plug, 243. diversion hole, 25. pair of wires, 3. microstructure battery pole piece, 31. current collector, 32. slurry base layer, 33. microstructure coating. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments of the specification. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0033] Example 1 See also Figure 1-Figure 17 , a slot coating die head of this embodiment includes: The feeding device 2 includes a quick-connect chuck 23, the quick-connect chuck 23 is connected to a feeding diverter block 24, and the feeding diverter block 24 includes a main pipeline 241 and sealing plugs 242 arranged at both ends of the main pipeline 241. Since the slurry coated on the battery pole piece is a non-Newtonian fluid, which mainly includes active substances, binders, conductive agents, etc., it has a certain viscosity. In this embodiment, by arranging sealing plugs 242 at both ends of the main pipeline 241, it can be easily disassembled and the main pipeline 241 can be quickly cleaned.

[0034] In this embodiment, the main pipeline 241 is also evenly provided with 5 diversion interfaces 243 along the length direction, and the 5 diversion interfaces 243 are respectively connected to the feed diversion pipeline 21. Therefore, the slurry flowing into the main pipeline 241 through the quick-connect chuck 23 will flow into the diversion pipeline 21 along the diversion interface 243 to form a supply branch.

[0035] The other end of any feed shunt pipeline 21 connected to the shunt interface 243 is provided with a proportional flow valve 22, and the proportional flow valve 22 is connected to the coating die 1 through the pair of wires 25. In this embodiment, by configuring a plurality of feed shunt pipelines 21 for the same coating die 1, the coating die 1 can be fed evenly along the length direction, which solves the problem that the feeding progress at both ends and the middle of the coating die 1 is difficult to unify due to the traditional coating die 1 only having one supply pipeline. On this basis, in this embodiment, by further providing a proportional flow valve 22 on the feed shunt pipeline 21, the speed at which the slurry in the corresponding feed shunt pipeline 21 flows into the coating die 1 can be better controlled, and the feeding flexibility and overall controllability are higher.

[0036] The pair of wires 25 is connected to the lower die head 13 of the coating die head 1. Specifically, the lower die head 13 is formed with 5 equally spaced diverter units 131 along the length direction. One end of the diverter unit 131 is connected to the pair of wires 25. Therefore, the slurry after the flow rate is regulated by the proportional flow valve 22 will flow along the pair of wires 25 into one end of the diverter unit 131 of the lower die head 13. In this embodiment, the diverter unit 131 is also formed with three-level two-diverter channels in the direction away from the pair of wires 25, and the spacing between the diverter channels of a single diverter unit 131 and the diverter units 131 is equal. The diverter unit 131 is provided with a feed cavity 132 connected to the five diverter units 131 at one end away from the pair of wires 25. The uniformity of the slurry feeding in the feeding chamber 132 will directly affect the coating effect. Therefore, based on the design of the proportional flow valve 22, this embodiment further provides a diversion unit 131 containing a multi-stage flow channel to make the slurry entering the feeding chamber 132 smoother, so that the overall discharge is more balanced.

[0037] The coating die 1 also includes a coating limit gasket 12 that is superimposed and fixedly arranged on the lower die 13. The coating limit gasket 12 is designed with a cavity of a certain width, and the size of the cavity is not less than the size of the feed cavity 132. In this embodiment, the coating thickness of the slurry base layer 32 can be controlled by setting the coating limit gasket 12. A microstructure gasket 14 is also provided on the coating limit gasket 12. The microstructure gasket 14 is also provided with a microstructure flow channel 142 for discharging the slurry on the side close to the coating limit gasket 12. In this embodiment, the microstructure flow channel 142 is a plurality of grooves arranged at intervals. The microstructure gasket 14 also includes a material transfer cavity 141 corresponding to the feed cavity 132, and the material transfer cavity 141 is connected to the microstructure flow channel 142.

[0038] In addition, the coating limiting gasket 12 is also superimposed and fixedly provided with an upper die head 11. When the coating limiting gasket 12, the microstructure gasket 14, and the upper die head 11 are superimposed and fixedly installed on the lower die head 13 in sequence, a discharge slit structure is formed on one side of the discharge end of the coating die head 1, so that during the coating process, the slurry in the feed cavity 132 will flow out evenly along the discharge slit structure, and then the slurry base layer 32 and the microstructure coating layer 33 are formed on the surface of the current collector 31 at one time, and a microstructure battery electrode is obtained.

[0039] The surface of the upper die head 11 is also provided with 5 pressure sensors 15 for measuring the slurry pressure at different positions in the feeding chamber 132. The monitoring probes of the 5 pressure sensors 15 are respectively used to collect the pressure data in the corresponding feeding chamber 132, and then the communication module of the pressure sensor 15 uploads the pressure data to the controller. The controller analyzes the multiple groups of pressure data and adjusts the corresponding proportional flow valve 22 according to the analysis results. By changing the size of the slurry flow rate flowing into the diversion unit 131, the slurry pressure in the feeding chamber 132 is overall regulated to reduce the pressure difference of the slurry at different positions in the feeding chamber 132, and realize the uniformity of the pressure in the length direction of the feeding chamber 132, so as to provide a guarantee for the uniform transportation of the slurry by the discharge slit structure, especially the microstructure flow channel 142.

[0040] Example 2 See also Figure 1-Figure 17 , this embodiment discloses the application of a slit coating die head described in embodiment 1 in coating of a current collector 31, specifically comprising the following steps: the slurry introduced from the quick-connect chuck 23 into the feed diversion block 24 flows along the main pipeline 241, and then flows into the feed diversion pipeline 21 through the diversion hole 243; the slurry in the feed diversion pipeline 21 flows into one end of the diversion unit 131 in the lower die head 13 under the control of the proportional flow valve 22; the slurry flowing into the diversion unit 131 flows along the three-level two-division channel to the feed cavity 132, and continuously accumulates in the feed cavity 132 and the transfer cavity 141 until the entire discharge slit structure is filled; finally, the slurry overflows the discharge slit structure and is evenly coated on the surface of the current collector 31. After coating, a slurry base layer 32 is evenly formed on the surface of the current collector 31, and a microstructure coating 33 is also equidistantly arranged on the upper surface of the slurry base layer 32.

[0041] In addition, in order to prevent the slurry from having difficulty in evenly flowing out of the groove-shaped microstructure flow channel 142, the application process of this embodiment also includes: using the pressure sensor 15 to measure the slurry pressure in the feed chamber 132 corresponding to the diversion unit 131; then the communication module of the pressure sensor 15 uploads the pressure data to the controller, and the controller analyzes the pressure data and adjusts the corresponding proportional flow valve 22 according to the analysis results, thereby adjusting the pressure in the feed chamber 132 to achieve uniform pressure in the length direction of the feed chamber 132, so that the slurry flows out evenly from the discharge slit structure.

[0042] Example 3 A slot coating die head of this embodiment includes: The feeding device 2 includes a quick-connect chuck 23, the quick-connect chuck 23 is connected to a feeding diverter block 24, and the feeding diverter block 24 includes a main pipeline 241 and sealing plugs 242 arranged at both ends of the main pipeline 241. Since the slurry coated on the battery pole piece is a non-Newtonian fluid, which mainly includes active substances, binders, conductive agents, etc., it has a certain viscosity. In this embodiment, by arranging sealing plugs 242 at both ends of the main pipeline 241, it can be easily disassembled and the main pipeline 241 can be quickly cleaned.

[0043] In this embodiment, the main pipeline 241 is also evenly provided with three diversion interfaces 243 along the length direction, and the three diversion interfaces 243 are respectively connected to the feed diversion pipeline 21. Therefore, the slurry flowing into the main pipeline 241 through the quick-connect chuck 23 will flow into the diversion pipeline 21 along the diversion interface 243 to form a supply branch.

[0044] The other end of any feed shunt pipeline 21 connected to the shunt interface 243 is provided with a proportional flow valve 22, and the proportional flow valve 22 is connected to the coating die 1 through the pair of wires 25. In this embodiment, by configuring a plurality of feed shunt pipelines 21 for the same coating die 1, the coating die 1 can be fed evenly along the length direction, which solves the problem that the feeding progress at both ends and the middle of the coating die 1 is difficult to unify due to the traditional coating die 1 only having one supply pipeline. On this basis, in this embodiment, by further providing a proportional flow valve 22 on the feed shunt pipeline 21, the speed at which the slurry in the corresponding feed shunt pipeline 21 flows into the coating die 1 can be better controlled, and the feeding flexibility and overall controllability are higher.

[0045] The pair of wires 25 is connected to the lower die head 13 of the coating die head 1. Specifically, the lower die head 13 is formed with three equally spaced diverter units 131 along the length direction. One end of the diverter unit 131 is connected to the pair of wires 25. Therefore, the slurry after the flow rate is regulated by the proportional flow valve 22 will flow along the pair of wires 25 into one end of the diverter unit 131 of the lower die head 13. In this embodiment, the diverter unit 131 is also formed with three-level two-diverter channels in the direction away from the pair of wires 25, and the spacing between the diverter channels of a single diverter unit 131 and the diverter units 131 is equal. The diverter unit 131 is provided with a feed cavity 132 connected to the three diverter units 131 at one end away from the pair of wires 25. The uniformity of the slurry feeding in the feeding chamber 132 will directly affect the coating effect. Therefore, based on the design of the proportional flow valve 22, this embodiment further provides a diversion unit 131 containing a multi-stage flow channel to make the slurry entering the feeding chamber 132 smoother, so that the overall discharge is more balanced.

[0046] The coating die 1 also includes a coating limit gasket 12 superimposed on the lower die 13, and a cavity of a certain width is designed on the coating limit gasket 12, and the size of the cavity is not less than the size of the feed cavity 132. In this embodiment, the coating thickness of the slurry base layer 32 can be controlled by setting the coating limit gasket 12. A microstructure gasket 14 is also provided on the coating limit gasket 12, and a microstructure flow channel 142 for discharging the slurry is also provided on the side of the microstructure gasket 14 close to the coating limit gasket 12. In this embodiment, the microstructure flow channel 142 is a plurality of grooves arranged at intervals, and one end of the plurality of grooves is connected to the feed cavity 132.

[0047] In addition, the coating limiting gasket 12 is also superimposed and fixedly provided with an upper die head 11. When the coating limiting gasket 12, the microstructure gasket 14, and the upper die head 11 are superimposed and fixedly installed on the lower die head 13 in sequence, a discharge slit structure is formed on one side of the discharge end of the coating die head 1, so that during the coating process, the slurry in the feed cavity 132 will flow out evenly along the discharge slit structure, and then the slurry base layer 32 and the microstructure coating layer 33 are formed on the surface of the current collector 31 at one time, and a microstructure battery electrode is obtained.

[0048] The surface of the upper die head 11 is also provided with three pressure sensors 15 for measuring the slurry pressure at different positions in the feed chamber 132. The monitoring probes of the three pressure sensors 15 are respectively used to collect the pressure data in the feed chamber 132 corresponding to the corresponding diversion unit 131, and then the communication module of the pressure sensor 15 uploads the pressure data to the controller. The controller analyzes multiple groups of pressure data and adjusts the corresponding proportional flow valve 22 according to the analysis results. By changing the size of the slurry flow rate flowing into the diversion unit 131, the slurry pressure in the feed chamber 132 is overall regulated to reduce the pressure difference of the slurry at different positions in the feed chamber 132, thereby achieving uniform pressure in the length direction of the feed chamber 132.

[0049] Example 4 This embodiment discloses the application of a slit coating die head described in Example 3 in coating, specifically including the following steps: the slurry introduced from the quick-connect chuck 23 into the feed diversion block 24 flows along the main pipeline 241, and then flows into the feed diversion pipeline 21 through the diversion hole 243; the slurry in the feed diversion pipeline 21 will flow into one end of the diversion unit 131 in the lower die head 13 under the control of the proportional flow valve 22; the slurry flowing into the diversion unit 131 finally flows to the feed cavity 132 along the three-level two-division channel, and continuously accumulates in the feed cavity 132 until the entire discharge slit structure is filled; finally overflows the discharge slit structure and is evenly coated on the surface of the current collector 31. The current collector 31 is coated with a slurry base layer 32, and the upper surface of the slurry base layer 32 is also equidistantly provided with a microstructure coating 33. In addition, in order to prevent the slurry from having difficulty in evenly flowing out of the groove-shaped microstructure flow channel 142, the application process of this embodiment also includes: using the pressure sensor 15 to measure the slurry pressure in the feed chamber 132 corresponding to the diversion unit 131; then the communication module of the pressure sensor 15 uploads the pressure data to the controller, and the controller analyzes the pressure data and adjusts the corresponding proportional flow valve 22 according to the analysis results, thereby adjusting the pressure in the feed chamber 132 to achieve uniform pressure in the length direction of the feed chamber 132, so that the slurry flows out evenly from the discharge slit structure.

[0050] Although the following terms are used more frequently in this paper: 1, coating die head, 11, upper die head, 12, coating limit gasket, 13, lower die head, 131, diversion unit, 132, feeding chamber, 14, microstructure gasket, 141, material transfer chamber, 142, microstructure flow channel, 15, pressure sensor, 2, feeding device, 21, feeding diversion pipeline, 22, proportional flow valve, 23, quick-connect chuck, 24, feeding diversion block, 241, main pipeline, 242, sealing plug, 243, diversion hole, 25, wire pair, 3, battery pole piece, 31, current collector, 32, slurry base layer, 33, microstructure coating, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A slit-type coating die, comprising a coating die (1) for coating a current collector with a slurry, and a feeding device (2) connected to the coating die (1) and used to provide the coating die (1) with slurry, wherein the coating die (1) comprises an upper die (11), a coating limit gasket (12), and a lower die (13) which are sequentially stacked and fixed, and characterized in that: A microstructured gasket (14) for performing microstructured coating on the current collector is also provided between the coating limiting gasket (12) and the upper die head (11), and a microstructured flow channel (142) for discharging slurry is also provided on a side of the microstructured gasket (14) close to the coating limiting gasket (12).

2. A slot coating die according to claim 1, characterized in that: The lower die head (13) is formed with a plurality of equally spaced flow diversion units (131) along the length direction, one end of the flow diversion unit (131) is connected to the feeding device (2), and an end of the flow diversion unit (131) away from the feeding device (2) is provided with a feeding cavity (132) connected to the plurality of flow diversion units (131), and the feeding cavity (132) is connected to the microstructure flow channel (142).

3. A slot coating die according to claim 2, characterized in that: The microstructure gasket (14) is further provided with a material transfer cavity (141) which is in continuous connection with the microstructure flow channel (142); the material transfer cavity (141) is arranged corresponding to the material supply cavity (132).

4. A slot coating die according to claim 2, characterized in that: The coating die head (1) further comprises a pressure sensor (15) for measuring the pressure of the slurry in the feed cavity (132) corresponding to the diversion unit (131).

5. A slot coating die according to claim 4, characterized in that: The feeding device (2) comprises a feeding diversion pipeline (21) connected to the diversion unit (131), and the feeding diversion pipeline (21) is also provided with a proportional flow valve (22) for controlling the flow rate of slurry flowing into the diversion unit (131), and the proportional flow valve (22) is electrically connected to the pressure sensor (15).

6. A slot coating die according to claim 5, characterized in that: The feeding device (2) further comprises a quick-connect chuck (23) and a feeding diversion block (24) connected to the quick-connect chuck (23); the feeding diversion block (24) comprises a main pipeline (241) and sealing plugs (242) arranged at both ends of the main pipeline (241); and a diversion hole (243) for connecting the feeding diversion pipeline (21) is also provided on the main pipeline (241).

7. Use of the slit coating die according to any one of claims 1 to 6 in coating battery pole pieces.

8. Use of a slot coating die according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, a monitoring probe of the pressure sensor (15) collects pressure data of the slurry in the feed chamber (132), and then a communication module of the pressure sensor (15) uploads the pressure data to a controller; S2. The controller analyzes and calculates the pressure data, and controls the proportional flow valve (22) to adjust the flow rate of the slurry flowing into the diversion unit (131) according to the analysis and calculation results.

9. A microstructured battery electrode produced by a slot coating die according to any one of claims 1 to 6.

10. The microstructure battery pole piece according to claim 9, characterized in that: A slurry base layer (32) is coated on the current collector (31) of the microstructured battery pole piece (3), and microstructured coatings (33) are equidistantly arranged on the surface of the slurry base layer (32).

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