Battery pole piece coating system

Abstract

The utility model provides a battery pole piece coating system. The battery pole piece coating system comprises a double-layer coating die head provided with a first die cavity and a second die cavity, and the first die cavity and the second die cavity are each provided with a first feeding port; the first mold cavity and the second mold cavity are each correspondingly provided with at least one feeding unit, each feeding unit comprises a feeding part, a conveying pipeline and a branch pipeline, each feeding part is provided with a containing cavity, the first end of each conveying pipeline communicates with the corresponding containing cavity, and the second end of each conveying pipeline communicates with the corresponding branch pipeline; the second end of the material conveying pipeline is communicated with the first feeding port in the corresponding first mold cavity or the second mold cavity, the first end of the branch pipeline is selectively communicated with the material conveying pipeline, and the second end of the branch pipeline is communicated with the containing cavity. According to the technical scheme, the battery pole piece coating system can solve the problem that a feeding system in the prior art is coagulated and agglomerated due to the fact that the feeding system does not flow for a long time.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery coating equipment technical field, specifically, relate to a kind of battery pole piece coating system. BACKGROUND

[0002] Lithium battery coating procedure as the key link of lithium battery production, its process maturity directly affects battery performance and production efficiency.Slit coating technology, especially the coating system of single layer die, has been widely used in lithium battery manufacturing, and the technology is relatively mature.However, with the continuous progress of battery technology, the performance requirements of electrode materials are increasing, and single-layer coating has been difficult to meet the needs of fine control of active material, conductive agent and binder and other key ingredients.Therefore, as a new solution, double-layer coating technology aims to spray different formulations of slurry on the current collector at the same time to form a layered pole piece, thereby improving the overall performance of the battery cell.However, in the prior art, the feeding system of the double-layer coating die has obvious defects.When the die is in a shutdown state, the feeding system will produce condensation and aggregation due to long-term non-flow, which not only affects the coating uniformity when restarting, but also may cause equipment blockage, increasing maintenance costs. SUMMARY

[0003] The main purpose of the utility model is to provide a battery pole piece coating system, which can solve the problem of condensation and aggregation of the feeding system in the prior art due to long-term non-flow.

[0004] To achieve the above purpose, the utility model provides a battery pole piece coating system, comprising: a double-layer coating die having a first die cavity and a second die cavity, a first feed inlet is arranged on the first die cavity and the second die cavity; at least two feeding units, at least one feeding unit is arranged corresponding to the first die cavity and the second die cavity, each feeding unit comprises a feeding part, a feeding pipe and a branch pipe, the feeding part has a containing cavity for containing slurry, the first end of the feeding pipe is communicated with the containing cavity, the second end of the feeding pipe is communicated with the first feed inlet on the corresponding first die cavity or second die cavity, the first end of the branch pipe is selectively communicated with the feeding pipe, and the second end of the branch pipe is communicated with the containing cavity.

[0005] Through the above arrangement, the branch pipe and the feeding pipe are selectively communicated.When the double-layer coating die needs to be cleaned or shut down, the slurry can be returned to the containing cavity of the feeding part through the branch pipe, and then flow out from the containing cavity, enter the branch pipe again through the feeding pipe, and return to the containing cavity of the feeding part through the branch pipe, realizing the circulation of the slurry outside the double-layer coating die, and thereby avoiding condensation and aggregation of the slurry due to long-term non-flow.

[0006] Further, the first mold cavity and the second mold cavity are further provided with a first discharge port, and the feeding unit further comprises a reflux pipeline, a first end of the reflux pipeline being in communication with the first discharge port on the corresponding first mold cavity or second mold cavity, and a second end of the reflux pipeline being in communication with the branch pipeline; and / or the feeding part further has a heat preservation layer, the heat preservation layer being located on the outer circumferential side of the accommodation cavity, and the heat preservation layer being used for heat preservation of the slurry in the accommodation cavity.

[0007] Through the above arrangement, the circulation of the slurry can be formed through the combined use of the reflux pipeline and the branch pipeline, and even in the shutdown state, the activity of the slurry can be maintained through the circulation, the active substance in the slurry is prevented from agglomerating, and the performance of the pole piece is affected. When it is necessary to clean or maintain the double-layer coating die head, the slurry in the mold cavity can be refluxed to the feeding unit, so that the mold cavity is conveniently cleaned. In addition, through the above arrangement, on the one hand, the temperature stability of the slurry in the conveying process can be maintained, the viscosity change of the slurry due to temperature fluctuation is avoided, and thus the stability and consistency of the slurry in the coating process are ensured, and on the other hand, when the equipment is shut down or the slurry conveying is paused, the slurry is prevented from coagulating and agglomerating to affect the coating effect when it is started again, and even to cause the equipment to be blocked.

[0008] Further, the feeding part comprises an inner shell and an outer shell sleeved on the outer circumferential side of the inner shell, a heat preservation layer is formed between the outer wall surface of the inner shell and the inner wall surface of the outer shell, an inner cavity of the inner shell forms an accommodation cavity, a second inlet, a second outlet and a reflux port in communication with the accommodation cavity are arranged on the inner shell, and a second end of the branch pipeline is in communication with the reflux port.

[0009] Through the above arrangement, the heat preservation of the slurry can be realized, and the slurry can be refluxed to the accommodation cavity when not in use.

[0010] Further, the battery pole piece coating system further comprises a temperature control assembly, the temperature control assembly comprising a temperature control part, a first liquid conveying pipeline and a second liquid conveying pipeline, the temperature control part being used for providing a heat preservation solution, an inlet and an outlet in communication with the heat preservation layer being arranged on the outer shell, one end of the first liquid conveying pipeline being in communication with the inlet, the other end of the first liquid conveying pipeline being connected with the temperature control part, one end of the second liquid conveying pipeline being in communication with the outlet, and the other end of the second liquid conveying pipeline being connected with the temperature control part.

[0011] Through the above arrangement, the temperature of the slurry in the liquid conveying pipeline and the feeding part can be kept constant, so that the viscosity fluctuation caused by the temperature change is avoided, and the performance stability of the slurry in the coating process is ensured.

[0012] Further, the feeding unit further comprises a moving part, the moving part having a mounting cavity, the feeding part being mounted in the mounting cavity, part of the liquid conveying pipeline and at least part of the branch pipeline being located in the mounting cavity, and the moving part comprising a roller located at the bottom of the moving part.

[0013] Through the above arrangement, the whole feeding unit is conveniently moved, without the need of using additional handling equipment or manpower, thus not only improving the flexibility of equipment layout, but also facilitating the cleaning, maintenance and replacement of the feeding unit, reducing downtime and improving production efficiency.

[0014] Further, along the first direction, the first mold cavity and the second mold cavity each have a first end and a second end arranged oppositely, and the first end and the second end are each provided with a first discharge port in communication with itself, the reflux pipeline comprises a collecting pipe and two branch reflux pipes, one end of the two branch reflux pipes is respectively in communication with the two first discharge ports of the corresponding first mold cavity or second mold cavity, the other end of the two branch reflux pipes is in communication with one end of the collecting pipe, and the other end of the collecting pipe is in communication with the branch pipeline.

[0015] Through the above arrangement, when slurry circulation is needed to prevent condensation or maintain slurry fluidity, the slurry flows from the first discharge port into the collecting pipe through the branch reflux pipe, and then flows into the branch pipeline and back into the accommodating cavity of the feeding part, forming an effective reflux circulation. By providing the first discharge port, the slurry can more flexibly flow out from either end or both ends of the first mold cavity or the second mold cavity during cleaning or downtime of the die head, and circulate through the reflux pipeline, ensuring the continuity and consistency of the slurry state, avoiding coating defects caused by slurry condensation, and facilitating equipment maintenance and slurry management.

[0016] Further, the first inlet on the first mold cavity is located between the two first discharge ports provided on the first mold cavity, and the first inlet on the second mold cavity is located between the two first discharge ports provided on the second mold cavity.

[0017] Through the above arrangement, on the one hand, after the slurry enters through the first inlet at the middle position, it can be more evenly distributed to both sides, reducing the possibility of slurry accumulation on one side in the mold cavity, and on the other hand, the first inlet is arranged in the middle, and the two first discharge ports are arranged on both sides of the first inlet, which helps to balance the slurry pressure in the mold cavity and avoid coating defects caused by uneven pressure, such as uneven coating thickness or air bubbles.

[0018] Further, the feeding unit further comprises a control valve arranged on the collecting pipe.

[0019] Through the above arrangement, the opening and closing of the collecting pipe and the branch pipeline can be controlled.

[0020] Further, the feeding unit further comprises a three-way valve, one end of a first feeding branch of the feeding pipeline is in communication with the accommodating cavity, a first interface of the three-way valve is in communication with the other end of the first feeding branch, a second interface of the three-way valve is in communication with a second feeding branch, and a third interface of the three-way valve is in communication with the branch pipeline.

[0021] Through the above setting, when the double-layer coating die needs to be slightly cleaned, the first material conveying branch and the branch pipeline can be communicated through the three-way valve to form the circulation of the slurry between the feeding part and the first material conveying branch, that is, the internal circulation, so that even in the case of no spraying, the slurry can be prevented from condensing or agglomerating in the pipeline, and the failure rate during the next start is reduced. When the double-layer coating die is in a shutdown state, the first material conveying branch and the second material conveying branch are communicated through the control of the three-way valve, and the first material conveying branch is communicated with the branch pipeline to realize the circulation of the slurry between the double-layer coating die and the feeding part, that is, the external circulation. The slurry can be continuously circulated during maintenance or shutdown of the equipment, the condensation and agglomeration of the slurry due to long-term non-flowing are avoided, and the problem of belt scraping and belt breaking after the next coating is effectively prevented.

[0022] Further, the feeding unit further comprises a dedusting unit, a filtering unit and a flow detection unit, and the dedusting unit, the filtering unit and the flow detection unit are sequentially arranged on the first material conveying branch along the conveying direction of the slurry.

[0023] Through the above setting, the ferromagnetic impurities in the slurry can be removed, and the solid impurities in the slurry can also be filtered.

[0024] The technical scheme of the utility model is applied, in the equipment operation process, the slurry in the accommodating cavity is conveyed to the first die cavity or the second die cavity corresponding to the accommodating cavity through the material conveying pipeline for coating, the branch pipeline and the material conveying pipeline are selectively communicated, and when the double-layer coating die needs to be cleaned or shut down, the slurry can return to the accommodating cavity of the feeding part through the branch pipeline, then flow out from the accommodating cavity, re-enter the branch pipeline through the material conveying pipeline, and then return to the accommodating cavity of the feeding part through the branch pipeline. The above setting can realize the circulation flow of the slurry outside the double-layer coating die, and thus the condensation and agglomeration of the slurry due to long-term non-flowing can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings accompanying the specification of the utility model form a part of the utility model and serve to provide further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions serve to explain the utility model, and do not constitute an improper limitation on the utility model. In the drawings:

[0026] Figure 1 An overall structure schematic diagram of a battery pole piece coating system of an embodiment of the utility model is shown;

[0027] Figure 2 A structure schematic diagram of a feeding unit of an embodiment of the utility model is shown;

[0028] Figure 3 A structure schematic diagram of a feeding part of an embodiment of the utility model is shown;

[0029] Figure 4 Part structure schematic view of the feeding unit of the embodiment of the utility model is shown;

[0030] Figure 5 Part structure schematic view of the battery pole piece coating system of the embodiment of the utility model is shown (wherein, the first mold body is partially perspective);

[0031] Figure 6 Part structure schematic view of the battery pole piece coating system of the embodiment of the utility model is shown (wherein, the first mold body and the second mold body are both perspective, and the third mold body is partially perspective);

[0032] Figure 7 The cross-sectional view of the double-layer coating die head of the embodiment of the utility model is shown.

[0033] Among them, the above-mentioned drawings include the following figure marks:

[0034] 10, double-layer coating die head;11, first mold cavity;111, first feeding port;112, first discharging port;12, second mold cavity;13, first mold body;131, first backflow channel;14, second mold body;15, third mold body;151, second backflow channel;16, first gasket;17, second gasket;18, control valve;20, feeding unit;21, feeding part;210, cover plate;211, accommodating cavity;212, heat preservation layer;213, inner shell;214, outer shell;215, second feeding port;216, second discharging port;217, backflow port;218, liquid inlet;219, liquid outlet;22, feeding pipeline;221, first feeding branch;222, second feeding branch;23, branch pipeline;24, backflow pipeline;241, converging pipe;242, branch backflow pipe;25, moving part;251, mounting cavity;252, roller;253, push-pull handrail;26, three-way valve;27, impurity removal unit;28, filtering unit;281, scraper filter;282, bladder filter;29, stirring device;30, temperature control assembly;31, temperature control part;32, first infusion pipeline;33, second infusion pipeline;40, screw pump;50, flow detection unit. DETAILED DESCRIPTION

[0035] It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict. The utility model will be described in detail below with reference to the drawings and in combination with the embodiments.

[0036] In combination with Figures 1 to 7The utility model provides a kind of battery pole piece coating system, the battery pole piece coating system includes: double-layer coating die head 10, with first die cavity 11 and second die cavity 12, first die cavity 11 and second die cavity 12 are all provided with first feed port 111;At least two feed units 20, first die cavity 11 and second die cavity 12 are all correspondingly provided with at least one feed unit 20, each feed unit 20 includes feed part 21, feed pipe line 22 and branch pipe line 23, feed part 21 has accommodating cavity 211, the first end of feed pipe line 22 is communicated with accommodating cavity 211, the second end of feed pipe line 22 is communicated with the first feed port 111 on corresponding first die cavity 11 or second die cavity 12, the first end of branch pipe line 23 is selectively communicated with feed pipe line 22, the second end of branch pipe line 23 is communicated with accommodating cavity 211.

[0037] In the embodiment, double-layer coating die head 10 has two independently arranged first die cavity 11 and second die cavity 12, first die cavity 11 and second die cavity 12 are all provided with first feed port 111, the arrangement of double-layer coating die head 10 and at least two feed units 20 can realize the coating of different slurry formulations respectively, and can also form upper and lower layers on the foil. That is, different slurry formulations can be used for upper and lower coating, so as to form upper and lower two layers of coating with different properties on the pole piece, which can optimize the performance of the pole piece. In the prior art, when the pole piece passes through the oven, part of the adhesive coated on the lower layer of the pole piece will migrate to the upper layer. Since the double-layer coating die head 10 of the present application can use different slurry formulations for upper and lower coating, the adhesive content in the slurry output from the first die cavity 11 can be lower than that in the slurry output from the second die cavity 12. The first die cavity 11 and the second die cavity 12 simultaneously spray on the current collector. The material sprayed from the second die cavity 12 is located on the bottom layer of the current collector, and the material sprayed from the first die cavity 11 is located on the upper layer of the bottom layer. By using the battery pole piece coating system of the present application, more adhesive can be retained in the lower layer of slurry, thereby enhancing the adhesion between the bottom layer of slurry and the pole piece and improving the performance of the pole piece. In addition, under the condition that the total amount of conductive agent remains unchanged, by using the battery pole piece coating system of the present application, different slurry formulations can be used for the upper and lower layers of slurry, so that the conductive agent content in the lower layer of slurry is lower than that in the upper layer of slurry, i.e., the lower layer of the coated pole piece has more conductive agent, thereby making the pole piece have better circuit conduction. In addition, by using the battery pole piece coating system of the present application, different slurry formulations can be used according to the types and sizes of active particles, so that the feed unit 20 supplying the first die cavity 11 uses particles with larger porosity, and the feed unit 20 supplying the second die cavity 12 uses particles with smaller porosity, which is beneficial to the migration of lithium ions in the electrode.

[0038] The accommodating cavity 211 of the feeding part 21 is used for containing slurry, and during equipment operation, the slurry in the accommodating cavity 211 is conveyed to the first die cavity 11 or the second die cavity 12 corresponding to the feeding pipeline 22 for coating, the branch pipeline 23 is selectively communicated with the feeding pipeline 22, and when the double-layer coating die head 10 needs to be cleaned or stopped, the slurry can return to the accommodating cavity 211 of the feeding part 21 through the branch pipeline 23, then flow out from the accommodating cavity 211, enter the branch pipeline 23 again through the feeding pipeline 22, and return to the accommodating cavity 211 of the feeding part 21 through the branch pipeline 23. The above-mentioned arrangement can realize the circulation of the slurry outside the double-layer coating die head 10, and thus the coagulation and aggregation of the slurry caused by long-time non-flowing can be avoided.

[0039] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the first die cavity 11 and the second die cavity 12 are both provided with a first discharge port 112, and the feeding unit 20 further comprises a reflux pipeline 24, the first end of the reflux pipeline 24 is communicated with the first discharge port 112 on the corresponding first die cavity 11 or second die cavity 12, and the second end of the reflux pipeline 24 is communicated with the branch pipeline 23.

[0040] In the embodiment, by arranging the reflux pipeline 24, the slurry can return to the branch pipeline 23 of the feeding unit 20 from the die cavity (the first die cavity 11 or the second die cavity 12) in the stopped state, and then return to the accommodating cavity 211 through the branch pipeline 23, thereby avoiding the problems of precipitation or dryness caused by long-time standing of the slurry in the die cavity. In addition, if the slurry is not completely used during coating, the excess slurry can be recycled to the feeding unit 20 through the reflux pipeline 24, thereby avoiding waste of the slurry. Through the combined use of the reflux pipeline 24 and the branch pipeline 23, the circulation of the slurry can be formed, and even in the stopped state, the activity of the slurry can be maintained through circulation, thereby preventing the aggregation of active substances in the slurry and affecting the performance of the pole piece. When the double-layer coating die head 10 needs to be cleaned or maintained, the slurry in the die cavity can return to the feeding unit 20, thereby facilitating the cleaning of the die cavity.

[0041] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the feeding part 21 further has a heat preservation layer 212, the heat preservation layer 212 is located at the outer circumferential side of the accommodating cavity 211, and the heat preservation layer 212 is used for heat preservation of the slurry in the accommodating cavity 211.

[0042] Through the above-mentioned arrangement, on the one hand, the temperature stability of the slurry during conveying can be maintained, and the change of the viscosity of the slurry caused by temperature fluctuation can be avoided, thereby ensuring the stability and consistency of the slurry during coating. On the other hand, when the equipment is stopped or the slurry conveying is paused, the coagulation and aggregation of the slurry can be avoided, thereby affecting the coating effect when starting again, and even causing equipment blockage.

[0043] In one embodiment, the temperature-maintaining layer 212 is filled with constant-temperature water to maintain the temperature of the slurry. The slurry under constant-temperature condition is less likely to precipitate, reducing the cleaning and maintenance work of the feeding pipeline 22 and the feeding part 21, simplifying the daily maintenance process of the equipment, and reducing the maintenance cost.

[0044] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the feeding part 21 comprises an inner shell 213 and an outer shell 214 sleeved on the outer periphery of the inner shell 213, a temperature-maintaining layer 212 is formed between the outer wall surface of the inner shell 213 and the inner wall surface of the outer shell 214, the inner cavity of the inner shell 213 forms a containing cavity 211, the inner shell 213 is provided with a second feeding port 215, a second discharging port 216 and a backflow port 217 communicated with the containing cavity 211, and the second end of the branch pipeline 23 is communicated with the backflow port 217.

[0045] In this embodiment, the second feeding port 215 is used to be connected with a device for supplying slurry from outside, the slurry in the containing cavity 211 can enter the feeding pipeline 22 through the second discharging port 216, and the slurry in the branch pipeline 23 can backflow to the containing cavity 211 through the backflow port 217. Through the above arrangement, the temperature of the slurry can be maintained, and the slurry can backflow to the containing cavity 211 when not in use.

[0046] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the second feeding port 215 is located at the top of the inner shell 213, and the second discharging port 216 is located at the bottom of the inner shell 213.

[0047] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the battery pole piece coating system further comprises a temperature control assembly 30, the temperature control assembly 30 comprises a temperature control part 31, a first liquid feeding pipeline 32 and a second liquid feeding pipeline 33, the temperature control part 31 is used to provide a temperature-maintaining solution, the outer shell 214 is provided with a liquid inlet 218 and a liquid outlet 219 communicated with the temperature-maintaining layer 212, one end of the first liquid feeding pipeline 32 is communicated with the liquid inlet 218, the other end of the first liquid feeding pipeline 32 is connected with the temperature control part 31, one end of the second liquid feeding pipeline 33 is communicated with the liquid outlet 219, and the other end of the second liquid feeding pipeline 33 is connected with the temperature control part 31.

[0048] In this embodiment, the temperature control part 31 provides the temperature-maintaining solution, and the temperature-maintaining solution is circulated to the temperature-maintaining layer 212 of the feeding part 21 through the first liquid feeding pipeline 32 and the second liquid feeding pipeline 33, so that the temperature of the slurry in the feeding pipeline 22 and the feeding part 21 can be kept constant, thereby avoiding the viscosity fluctuation of the slurry due to temperature change, and ensuring the performance stability of the slurry in the coating process. In addition, the arrangement of the temperature control assembly 30 can avoid the temperature of the slurry being too low, reduce the condensation and agglomeration phenomenon, and ensure that the slurry is in good condition and uniformly coated when restarted.

[0049] In one embodiment, the temperature control unit 31 is a mold temperature controller for constant temperature heating of water, and the first and second infusion pipelines 32 and 33 are both heat-insulated pipelines. The constant temperature water flows into the heat-insulating layer 212 through the inlet 218, and then flows out through the outlet 219 and returns to the temperature control unit 31 through the second infusion pipeline 33. The constant temperature water circulates between the heat-insulating layer 212 and the temperature control unit 31, which can reduce heat loss and form a heat-insulating effect on the slurry in the accommodating cavity 211, thereby reducing viscosity fluctuation and enhancing the consistency of the surface density after coating.

[0050] Referring to Figures 1 to 7 In one embodiment of the utility model, the shell 214 is a cylindrical structure, the inlet 218 is located at the top of the shell 214, and the outlet 219 is located at the bottom of the shell 214. The inlet 218 and the outlet 219 are arranged along the radial direction of the shell 214.

[0051] Referring to Figures 1 to 7 In one embodiment of the utility model, the feeding unit 20 further comprises a stirring device 29, a cover plate 210 and a lifting device (not shown in the figure). The stirring device 29 is arranged in the accommodating cavity 211 and is used for stirring the slurry in the accommodating cavity 211. The cover plate 210 is arranged on the top of the feeding unit 21, and the lifting device is used for lifting the cover plate 210.

[0052] Specifically, the lifting device can be an electric telescopic rod.

[0053] Referring to Figures 1 to 7 In one embodiment of the utility model, the feeding unit 20 further comprises a moving unit 25. The moving unit 25 has a mounting cavity 251, and the feeding unit 21 is mounted in the mounting cavity 251. Part of the feeding pipeline 22 and at least part of the branch pipeline 23 are located in the mounting cavity 251. The moving unit 25 comprises a roller 252 located at the bottom of the moving unit 25.

[0054] Referring to Figure 1 and Figure 2 In one embodiment of the utility model, the moving unit 25 further comprises a push-pull handrail 253. The push-pull handrail 253 is fixedly installed on the moving unit 25, which facilitates the pushing and pulling of the moving unit 25.

[0055] In this embodiment, the moving unit 25 comprises the roller 252 located at the bottom of the moving unit 25, and the feeding unit 21 is mounted in the mounting cavity 251. Since the bottom of the moving unit 25 is equipped with the roller 252, it is convenient to move the entire feeding unit 20 without the need for additional handling equipment or manpower. This not only improves the flexibility of equipment layout, but also facilitates the cleaning, maintenance and replacement of the feeding unit 20, reduces downtime and improves production efficiency.

[0056] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, along the first direction, the first mold cavity 11 and the second mold cavity 12 both have oppositely arranged first ends and second ends, the first ends and the second ends are both provided with the first discharge port 112 communicated with itself, the reflux pipeline 24 includes the collecting pipe 241 and two branch reflux pipes 242, one end of the two branch reflux pipes 242 is respectively communicated with the two first discharge ports 112 of the corresponding first mold cavity 11 or the second mold cavity 12, the other end of the two branch reflux pipes 242 is all communicated with one end of the collecting pipe 241, the other end of the collecting pipe 241 is communicated with the branch pipeline 23. The feeding unit 20 further includes the control valve 18, the control valve 18 is arranged on the collecting pipe 241.

[0057] In the embodiment, the first direction refers to the length extension direction of the first mold cavity 11. The control valve 18 is arranged on the collecting pipe 241 and is used for controlling the on-off of the collecting pipe 241 and the branch pipeline 23. Through the above arrangement, when the slurry needs to be circulated to prevent condensation or keep the slurry flowability, opening the corresponding control valve 18 can make the slurry flow from the first discharge port 112 into the collecting pipe 241 through the branch reflux pipe 242, and then flow into the branch pipeline 23 and return to the containing cavity 211 of the feeding part 21, forming an effective reflux circulation. Through the arrangement of the first discharge port 112, when the die head needs to be cleaned or during shutdown, the slurry can more flexibly flow out from either end or both ends of the first mold cavity 11 or the second mold cavity 12, circulate through the reflux pipeline 24, ensure the continuity and consistency of the slurry state, avoid the coating defects caused by slurry condensation, and also facilitate equipment maintenance and slurry management. At the same time, the design of the two branch reflux pipes 242 can ensure the reflux rate.

[0058] With reference to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the first feeding port 111 on the first mold cavity 11 is located between the two first discharge ports 112 arranged on the first mold cavity 11, and the first feeding port 111 on the second mold cavity 12 is located between the two first discharge ports 112 arranged on the second mold cavity 12.

[0059] Through the above arrangement, on the one hand, after the slurry enters through the first feeding port 111 at the middle position, it can be more evenly distributed to both sides, reducing the possibility of slurry accumulation on one side of the mold cavity, and on the other hand, the first feeding port 111 is arranged in the middle, and the two first discharge ports 112 are arranged on both sides of the first feeding port 111, which helps to balance the slurry pressure in the mold cavity and avoid coating defects caused by uneven pressure, such as uneven coating thickness or air bubbles.

[0060] With reference to Figures 1 to 7As shown in the drawings, in one embodiment of the utility model, the material conveying pipeline 22 comprises a first material conveying branch 221 and a second material conveying branch 222, the material supply unit 20 further comprises a three-way valve 26, one end of the first material conveying branch 221 is communicated with the accommodating cavity 211, a first interface of the three-way valve 26 is communicated with the other end of the first material conveying branch 221, a second interface of the three-way valve 26 is communicated with the second material conveying branch 222, and a third interface of the three-way valve 26 is communicated with the branch pipeline 23.

[0061] Through the above arrangement, when the double-layer coating die 10 needs to be micro-cleaned, the first material conveying branch 221 and the branch pipeline 23 can be communicated through the three-way valve 26 to form the circulation of the slurry between the material supply part 21 and the first material conveying branch 221, that is, the internal circulation, so that even in the case of no spraying, the slurry can be prevented from coagulating or agglomerating in the pipeline, and the failure rate when starting again is reduced. When the double-layer coating die 10 is in a shutdown state, the first material conveying branch 221 and the second material conveying branch 222 are communicated, and the first material conveying branch 221 and the branch pipeline 23 are communicated through the control of the three-way valve 26, so that the circulation of the slurry between the double-layer coating die 10 and the material supply part 21 is realized, that is, the external circulation. The slurry can be continuously circulated during maintenance or shutdown of the equipment, the coagulation and agglomeration of the slurry due to long-term non-flowing are avoided, and the problem of scratch strip breakage (scratch strip refers to the discontinuity or thickness mutation of the coating layer in the coating process) after starting again is effectively prevented.

[0062] For reference Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the material supply unit 20 further comprises a foreign matter removing unit 27, a filtering unit 28 and a flow detection unit 50, and the foreign matter removing unit 27, the filtering unit 28 and the flow detection unit 50 are sequentially arranged on the first material conveying branch 221 along the conveying direction of the slurry.

[0063] In the embodiment, the foreign matter removing unit 27 is used for removing ferromagnetic impurities in the slurry. The filtering unit 28 comprises a scraper filter 281 and a capsule filter 282, and the structures of the scraper filter 281 and the capsule filter 282 are all adopted in the prior art. The scraper filter 281 filters through the filter screen and the rotating scraper in the interior, the filter screen can block the solid impurities in the slurry, and the scraper can periodically or continuously remove the accumulated impurities on the filter screen to prevent the filter screen from being blocked and ensure the continuous flow of the slurry. The capsule filter 282 uses a filter capsule as a filter medium, when the slurry passes through the filter capsule, the impurities are intercepted in the capsule, and the pure slurry flows out through the pore diameter of the filter capsule to enter the subsequent processing or coating link.

[0064] In one embodiment, the impurity removal unit 27 is a de-ironer, and the flow detection unit 50 is a flow meter. The slurry flow is precisely controlled by the flow meter, so that the double-layer coating thickness on the foil can be precisely controlled, and the upper and lower coatings are tightly combined, effectively increasing the performance of the pole piece and the battery cell.

[0065] Referring to Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the feeding unit 20 further includes a screw pump 40, which is used to deliver the slurry in the accommodating cavity 211 to the feeding pipeline 22.

[0066] Referring to Figures 1 to 7 Figures 1 to 7 As shown in the drawings, in one embodiment of the utility model, the feeding unit 20 is two, one of which is arranged corresponding to the first mold cavity 11, and the other is arranged corresponding to the second mold cavity 12. The double-layer coating die head 10 includes a first mold body 13, a second mold body 14, a third mold body 15, a first gasket 16, a second gasket 17, and two pressure detection devices. The first mold body 13, the first gasket 16, the second mold body 14, the second gasket 17, and the third mold body 15 are sequentially stacked in the vertical direction. The first mold cavity 11 is surrounded by the bottom of the first mold body 13, the first gasket 16, and the top of the second mold body 14. The second mold cavity 12 is surrounded by the bottom of the second mold body 14, the second gasket 17, and the top of the third mold body 15. Two first return channels 131 are arranged in the first mold body 13, and the two first return channels 131 are arranged at both ends of the first mold cavity 11 in the first direction. The two first return channels 131 are arranged corresponding to and communicating with the two first discharge ports 112 of the first mold cavity 11. Two branch return pipes 242 corresponding to the first mold cavity 11 are arranged to communicate with the two first return channels 131, respectively. Two second return channels 151 are arranged in the third mold body 15, and the two second return channels 151 are arranged at both ends of the second mold cavity 12 in the first direction. The two second return channels 151 are arranged corresponding to and communicating with the two first discharge ports 112 of the third mold cavity. Two branch return pipes 242 corresponding to the second mold cavity 12 are arranged to communicate with the two second return channels 151, respectively.

[0067] Specifically, the two pressure detection devices are pressure sensors, which are used to detect the pressure of the first mold cavity 11 and the second mold cavity 12, respectively.

[0068] From the above description, it can be seen that the above-mentioned embodiments of the utility model realize the following technical effects: in the equipment operation process, the slurry in the accommodating cavity is conveyed to the first mold cavity or the second mold cavity corresponding to it through the feeding pipeline for coating, the branch pipeline and the feeding pipeline are selectively communicated, and when the double-layer coating die head needs to be cleaned or stopped, the slurry can return to the accommodating cavity of the feeding part through the branch pipeline, then flow out from the accommodating cavity, enter the branch pipeline again through the feeding pipeline, and then return to the accommodating cavity of the feeding part through the branch pipeline, the above-mentioned setting can realize the circulating flow of the slurry outside the double-layer coating die head, and then the coagulation and agglomeration of the slurry caused by long-time non-flowing can be avoided.

[0069] Obviously, the above-described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the utility model.

[0070] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, work, device, component and / or their combinations.

[0071] The above only describes the preferred embodiments of the utility model, and is not used to limit the utility model, and for those skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A battery pole piece coating system characterized by, The application relates to a battery pole piece coating system. The battery pole piece coating system comprises a double-layer coating die head (10) provided with a first die cavity (11) and a second die cavity (12), and a first feeding port (111) is arranged on each of the first die cavity (11) and the second die cavity (12); at least two feeding units (20) are arranged on the first die cavity (11) and the second die cavity (12) correspondingly, each of the feeding units (20) comprises a feeding part (21), a feeding pipeline (22) and a branch pipeline (23), the feeding part (21) is provided with a containing cavity (211), a first end of the feeding pipeline (22) is communicated with the containing cavity (211), a second end of the feeding pipeline (22) is communicated with the first feeding port (111) on the corresponding first die cavity (11) or second die cavity (12), and a first end of the branch pipeline (23) is selectively communicated with the feeding pipeline (22), and a second end of the branch pipeline (23) is communicated with the containing cavity (211). The first die cavity (11) and the second die cavity (12) are further provided with a first discharging port (112), the feeding unit (20) further comprises a reflux pipeline (24), a first end of the reflux pipeline (24) is communicated with the first discharging port (112) on the corresponding first die cavity (11) or second die cavity (12), and a second end of the reflux pipeline (24) is communicated with the branch pipeline (23); and / or the feeding part (21) is further provided with a heat preservation layer (212), the heat preservation layer (212) is arranged on the outer circumferential side of the containing cavity (211), and the heat preservation layer (212) is used for heat preservation of slurry in the containing cavity (211).

2. The battery pole piece coating system of claim 1, wherein, The feeding part (21) comprises an inner shell (213) and an outer shell (214) sleeved on the outer circumferential side of the inner shell (213), the heat preservation layer (212) is formed between the outer wall surface of the inner shell (213) and the inner wall surface of the outer shell (214), the inner cavity of the inner shell (213) forms the containing cavity (211), and the inner shell (213) is provided with a second feeding port (215), a second discharging port (216) and a reflux port (217) communicated with the containing cavity (211), and the second end of the branch pipeline (23) is communicated with the reflux port (217).

3. The battery pole piece coating system of claim 2, wherein, The battery pole piece coating system further comprises a temperature control assembly (30), the temperature control assembly (30) comprises a temperature control part (31) used for providing a heat preservation solution, a first liquid conveying pipeline (32) and a second liquid conveying pipeline (33), the outer shell (214) is provided with a liquid inlet (218) and a liquid outlet (219) communicated with the heat preservation layer (212), one end of the first liquid conveying pipeline (32) is communicated with the liquid inlet (218), the other end of the first liquid conveying pipeline (32) is connected with the temperature control part (31), one end of the second liquid conveying pipeline (33) is communicated with the liquid outlet (219), and the other end of the second liquid conveying pipeline (33) is connected with the temperature control part (31).

4. The battery pole piece coating system of claim 3, wherein, ​ 5. The battery pole piece coating system of any one of claims 1 to 4, wherein, The feeding unit (20) further comprises a moving part (25) having a mounting cavity (251) in which the feeding part (21) is mounted, and in which part of the feeding pipeline (22) and at least part of the branch pipeline (23) are located, the moving part (25) comprising a roller (252) at the bottom thereof.

6. The battery pole piece coating system of any one of claims 2-4, wherein, In the first direction, the first mold cavity (11) and the second mold cavity (12) each have oppositely arranged first and second ends, each of which is provided with the first discharge port (112) in communication therewith, the return pipeline (24) comprising a converging pipe (241) and two branch return pipelines (242), one end of each of the two branch return pipelines (242) being in communication with the two first discharge ports (112) of the corresponding first mold cavity (11) or second mold cavity (12), the other end of each of the two branch return pipelines (242) being in communication with one end of the converging pipe (241), and the other end of the converging pipe (241) being in communication with the branch pipeline (23).

7. The battery pole piece coating system of claim 6, wherein, The first feeding port (111) on the first mold cavity (11) is located between the two first discharge ports (112) provided on the first mold cavity (11), and the first feeding port (111) on the second mold cavity (12) is located between the two first discharge ports (112) provided on the second mold cavity (12).

8. The battery pole piece coating system of claim 6, wherein, The feeding unit (20) further comprises a control valve (18) provided on the converging pipe (241).

9. The battery pole piece coating system of any one of claims 2-4, wherein, The feeding pipeline (22) comprises a first feeding branch (221) and a second feeding branch (222), and the feeding unit (20) further comprises a three-way valve (26), one end of the first feeding branch (221) being in communication with the accommodating cavity (211), a first interface of the three-way valve (26) being in communication with the other end of the first feeding branch (221), a second interface of the three-way valve (26) being in communication with the second feeding branch (222), and a third interface of the three-way valve (26) being in communication with the branch pipeline (23).

10. The battery pole piece coating system of claim 9, wherein, The feeding unit (20) further comprises a dedusting unit (27), a filtering unit (28), and a flow detection unit (50), which are sequentially arranged on the first feeding branch (221) in the direction of slurry conveying.

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