Insulating adhesive coating system for current collector

Abstract

The utility model discloses a current collector insulating glue coating system which comprises a coating mechanism which adopts a gravure roller device. The gravure roller device can rotate along the axis of the gravure roller device, the gravure roller device comprises an insulating glue coating area, the insulating glue coating area is a gravure anilox roller, the mesh shape of the gravure anilox roller is an oblique line, and the angle of the oblique line is 40-50 degrees. According to the current collector insulating glue coating system, the uniformity of coating insulating glue is better, the coating thickness can be reduced, the use requirement can be met, and the coating efficiency is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technical field, concretely relates to a current collector insulating glue coating system. BACKGROUND

[0002] Lithium battery contains positive pole, negative pole, diaphragm, electrolyte and other materials, and the temperature in the battery will rise sharply under some abuse conditions, such as overcharge, high temperature environment, super large ratio charge and discharge, etc. The diaphragm of lithium battery is a kind of porous polyolefin material between positive pole and negative pole, when the temperature rises, the bond structure between polyolefin chains will change, thereby causing the shrinkage of diaphragm, when the shrinkage size reaches a certain degree, the positive pole and negative pole directly contact, which will cause the short circuit of battery. Therefore, a layer of insulating ceramic glue (coated after mixing ceramic particles and adhesive) is usually coated on the edge of positive pole sheet, when the diaphragm slightly shrinks, the insulating ceramic glue can play an insulating role to avoid short circuit.

[0003] At present, the action of coating insulating ceramic glue is that the battery manufacturer uses slit type extrusion to synchronously coat insulating ceramic glue when coating positive pole active material of the battery. However, the existing insulating ceramic glue coating has the following problems: ① the thickness of coated ceramic glue is relatively thick, the coating area density is high, which leads to the low energy density of battery cell; ② the viscosity of ceramic glue is low, the slurry is prone to flow leveling, and the slit type extrusion mode is difficult to ensure the coating uniformity in TD direction (transverse direction); ③ the cost of slit type extruder is high, which increases the purchase and maintenance cost. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a current collector insulating glue coating system to improve the coating effect of current collector insulating glue and solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the utility model provides the technical scheme:

[0006] A current collector insulating glue coating system, comprising a coating mechanism, wherein the coating mechanism adopts a gravure roll device; the gravure roll device can rotate along its axis, and the gravure roll device contains an insulating glue coating area, which is a gravure anilox roll with inclined lines as the shape of mesh, and the angle of inclined lines is 40-50°.

[0007] To optimize the above-mentioned technical scheme, the specific measures taken also include:

[0008] The line number of gravure anilox roll is 80-200 LPI, and the groove depth is 20-120 μm.

[0009] The both ends of the gravure roll device are roll shaft ends, and the roll shaft ends are carbon slurry coating area and insulating adhesive coating area.

[0010] The coating system further comprises a carbon slurry coating groove corresponding to the position of the carbon slurry coating area and an insulating adhesive groove corresponding to the position of the insulating adhesive coating area. The carbon slurry coating groove is filled with carbon slurry, which is used to coat the carbon slurry to the carbon coating area of the current collector foil when the gravure roll device rotates. The insulating adhesive groove is filled with insulating adhesive, which is used to coat the insulating adhesive to the insulating adhesive coating area of the current collector foil when the gravure roll device rotates.

[0011] Further, the width of the annular protruding structure of the insulating adhesive coating area is 3-9 mm, and the annular protruding structure can be removed or installed.

[0012] The coating system further comprises a unwinding mechanism, a traction mechanism and a winding mechanism. One end of the coating system is the unwinding mechanism, and the other end is the winding mechanism. The front coating mechanism and the back coating mechanism are arranged between the unwinding mechanism and the winding mechanism, and the traction mechanism is arranged between the mechanisms for traction and guidance.

[0013] Further, the coating system further comprises a drying device, and the drying device comprises a first drying device arranged after the front coating mechanism and a second drying device arranged after the back coating mechanism. The drying device is used for drying the current collector foil.

[0014] The gravure roll device is provided with a plurality of groups of carbon slurry coating areas and insulating adhesive coating areas, which can simultaneously coat the parallel coating areas of the whole current collector foil.

[0015] In the plurality of groups of carbon slurry coating areas and insulating adhesive coating areas, the two sides of each group of carbon slurry coating areas are provided with insulating adhesive coating areas, and the side of the insulating adhesive coating area away from the carbon slurry coating area is provided with a tab blank area. The diameter of the gravure roll body of the tab blank area is smaller than that of the carbon slurry coating area.

[0016] The traction mechanism comprises a flattening roller and a tension roller for adjusting the current collector pattern. The flattening roller and the tension roller can be selected and positioned as needed.

[0017] Compared with the prior art, the coating system has the following beneficial effects:

[0018] The current collector insulation glue coating system can make the current collector insulation glue coating and the current collector carbon slurry coating share one set of system, and the current collector insulation glue coating can be completed in the current collector carbon slurry coating stage, and the battery cell manufacturer for purchasing the carbon coated current collector does not need to carry out the later processing.

[0019] The insulation glue coating area of the current collector insulation glue coating system adopts the gravure anilox roller, the mesh shape of the gravure anilox roller is diagonal lines, when the gravure anilox roller rotates, the coating liquid flows along the direction of the diagonal lines, by controlling the angle of the diagonal lines, the distribution of the coating liquid on the surface of the roller body is more uniform, and the coating layer is more flat, so that the coating defects are reduced, and the coating quality is improved; by designing the thread number and groove depth parameters of the gravure anilox roller, the uniform spreading of the coating layer can be further optimized, and the coating of the ultra-thin insulation glue is realized. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The current collector insulation glue coating system of the utility model has the advantages of the following aspects.

[0021] Figure 2 The structure schematic diagram of the coating mechanism.

[0022] Figure 3 The structure schematic diagram of the coating mechanism after removing the annular convex structure.

[0023] In the drawing: 1-winding mechanism, 2-pulling mechanism, 3-coating mechanism, 4-winding mechanism, 5-roller shaft end, 6-carbon slurry coating area, 7-insulation glue coating area, 8-tab blank area, 9-drying device. DETAILED DESCRIPTION

[0024] The above content of the utility model will be further explained in the form of examples, but this should not be understood as the range of the above subject matter of the utility model being limited to the following examples, and all the technologies realized based on the above content of the utility model belong to the range of the utility model.

[0025] In the description of the utility model, it should be further pointed out that:

[0026] The orientation or position relationship in the utility model is the relationship shown in the drawing, and is only used for facilitating the description of the utility model and simplifying the description, and does not indicate or imply that the indicated device or component must have a specific orientation, a specific orientation structure and operation, and therefore cannot be understood as a limitation on the utility model.

[0027] In addition, terms such as "first, second" are only used for description purposes, and cannot be understood as indicating or implying relative importance, and the specific meaning of the above terms in the utility model can be understood by those skilled in the art according to specific circumstances.

[0028] The utility model provides a kind of insulating glue coating system of current collector, including the unwinding mechanism 1 of being connected into coating system, traction mechanism 2, coating mechanism 3 and winding mechanism 4;

[0029] Coating mechanism 3 uses gravure roll device, and the both ends of gravure roll device are roll shaft end 5, and the roll shaft end 5 between both ends is coating area, and gravure roll device can rotate along its axis line;

[0030] The insulating glue coating area of gravure roll device is gravure anilox roll, and the mesh shape of gravure anilox roll is diagonal line, and the angle of diagonal line is 40~50 °, and preferably 45 °;The uniformity of insulating glue is better using diagonal line gravure anilox roll pattern, and coating thickness is reduced simultaneously.

[0031] When diagonal stripe anilox roll rotates, coating liquid will flow along the direction of diagonal stripe. By controlling the angle of diagonal stripe, the distribution of coating liquid on the surface of roll body can be more uniform, and in the coating process, the coating layer is more flat, avoiding excessive accumulation of coating liquid at one end or edge of roll body, reducing the defects such as inconsistent coating thickness and stripes caused by uneven flow of coating liquid. In the coating process, diagonal stripe can also reduce the aggregation of unstable bubbles in coating liquid, thereby improving the coating quality. Moreover, the diagonal stripe is easy to clean, which is conducive to reducing the accumulation of solid particles in slurry. Through test, the coating product has high flatness by using 40~50 ° angle diagonal line gravure anilox roll, and the thickness fluctuation is within ±30%.

[0032] In some embodiments, the line number of gravure anilox roll is 80~200 LPI, and the groove depth is 50~120 μm. By designing these parameters of gravure anilox roll in combination with the angle parameter of diagonal line, the accumulation of coating liquid can be effectively reduced, the coating thickness is uniform, the uniform spreading of coating layer is realized, the coating defects are reduced, and the coating of ultra-thin insulating glue is realized. For example, in some example test, the insulating glue is coated by using diagonal line gravure anilox roll with 48 ° angle, 180 line number and 30 groove depth, and the thickness of insulating glue can be as thin as about 0.5 microns, and the test shows that the ultra-thin insulating glue has little defect and high flatness, which can meet the use requirement.

[0033] The coating area includes carbon slurry coating area 6 and insulating glue coating area 7, and the width of carbon slurry coating area is matched with the carbon coating area of current collector, and the width of insulating glue coating area 7 is matched with the insulating glue coating area of current collector.

[0034] The coating system is provided with a carbon slurry coating groove corresponding to the position of the carbon slurry coating area 6 and an insulating glue groove corresponding to the position of the insulating glue coating area 7.

[0035] The carbon slurry groove is filled with carbon slurry, which is used to coat the carbon slurry on the current collector foil in the carbon slurry coating area when the gravure roll device rotates. The insulating glue groove is filled with insulating glue, which is used to coat the insulating glue on the current collector foil in the insulating glue coating area when the gravure roll device rotates.

[0036] The insulating glue coating area 7 is an annular protruding structure on both sides of the carbon slurry coating area of the gravure roll body, which can be removed or installed. The coating mechanism after the annular protruding structure is removed is shown in FIG. 4. Figure 3 The annular protruding structure can be removed or installed by referring to the prior art, such as by setting a groove in the corresponding position of the gravure roll body to make the annular protruding structure clamped in the groove. In order to facilitate disassembly and assembly, the annular protruding structure can also be divided into two half rings, which are firmly installed by screws in the threaded holes provided in the groove. Other installation methods can also be used.

[0037] The width of the annular protruding structure is 3-9 mm. The protruding structure shape can accurately coat the insulating glue coating area of the current collector foil in the insulating glue coating area 7, and cooperate with the height of the insulating glue in the insulating glue groove to accurately control the thickness of the insulating glue on the current collector foil.

[0038] One end of the coating system is the unwinding mechanism 1, and the other end is the winding mechanism 4. The front coating mechanism 3, the back coating mechanism 3, and the traction mechanism 2 for traction and guidance between the mechanisms are provided between the unwinding mechanism 1 and the winding mechanism 4.

[0039] In some embodiments, the coating system further comprises a drying device 9, which comprises a first drying device provided after the front coating mechanism 3 and a second drying device provided after the back coating mechanism 3. The drying device 9 is used to dry the current collector foil.

[0040] Preferably, the gravure roll device is provided with several groups of carbon slurry coating areas 6 and insulating glue coating areas 7, which can simultaneously coat the parallel coating areas of the whole uncut current collector foil.

[0041] In some embodiments, among the several groups of carbon slurry coating areas 6 and insulating glue coating areas 7, the two sides of each group of carbon slurry coating areas 6 are provided with insulating glue coating areas 7, and the side away from the carbon slurry coating area 6 of the insulating glue coating area 7 is provided with a tab blank area 8, and the roll body diameter of the tab blank area 8 is smaller than the roll body diameter of the carbon slurry coating area 6.

[0042] In some embodiments, the traction mechanism 2 includes a flattening roller and a tension roller for performing the current collector pattern adjustment, which can be selected and positioned as needed.

[0043] When the current collector insulation glue coating system is in use, the current collector foil to be coated is passed through the unwinding mechanism 1 to run in the system, and first, the coating of carbon paste on both sides of the current collector foil is performed, and a carbon paste tank is placed below the coating mechanism 3. At this time, the annular protruding structure is not installed, and only the roller body of the gravure roller is immersed in the carbon paste tank to coat the carbon paste on the current collector foil. Since the diameter of the roller body of the tab blank area 8 is smaller than that of the carbon paste coating area 6, the roller body of the tab blank area 8 is not immersed in the carbon paste tank by setting the diameter.

[0044] According to the above operation, the coating of carbon paste on both sides of the current collector foil is completed by the forward and reverse groups of coating mechanisms 3.

[0045] After the current collector foil is wound by the winding mechanism 4, the annular protruding structure is installed at the corresponding position of the insulation glue coating area 7 of the gravure roller body, and the current collector foil that has completed the coating of carbon paste is passed through the unwinding mechanism 1 to run in the system. An insulation glue tank is placed below the coating mechanism 3, and the annular protruding structure is immersed in the insulation glue tank to coat the insulation glue on the current collector foil during the rotation of the gravure roller.

[0046] In this way, the coating of the carbon coating area and the insulation glue coating area of the current collector can be completed by using one set of system. In addition, the coating of the parallel coating area of the whole current collector foil can be realized, and the coating efficiency is high.

[0047] The existing battery manufacturers generally use a slit type extrusion synchronous coating method to coat the positive active material of the battery, and the coating thickness of the insulation ceramic glue is generally 20-100 μm. However, the current collector insulation glue coating system of the present application can reduce the coating thickness to within 1 μm, and the thickness tolerance can be limited within ± 0.5 μm, thereby improving the coating uniformity and reducing the coating thickness, slightly reducing the weight of the pole piece, and correspondingly improving the energy density of the battery.

[0048] A group of current collector foil sample coating examples are taken as examples to examine the effect. The insulation glue coating area uses a gravure anilox roller, the mesh shape is a diagonal line, and the angle of the diagonal line is 45°. The line number of the gravure anilox roller is 120 LPI, and the groove depth is 70 μm. The coating test results are as follows:

[0049] (1) The measured thickness of the tab glue coating is 0.9 μm, which is significantly thinner than the tab glue coating thickness of no less than 20 μm of the battery manufacturers.

[0050] (2) Test 5 groups of tab glue thickness along MD direction, the measured values are 0.88, 0.91, 0.90, 0.92, 0.90 μm respectively, the coating thickness uniformity effect is good;

[0051] (3) The tab glue coating area is removed, the actual object is observed using SEM, it is confirmed that the tab insulation glue is not coated by mistake in this way, and the insulation can be guaranteed.

[0052] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any skilled person in the art, without departing from the technical scheme of the present application, according to the technical essence of the present application, any simple modification, equivalent replacement and improvement of the above embodiments, etc. still belong to the protection scope of the technical scheme of the present application.

Claims

1. A current collector insulating adhesive coating system, characterized in that: The device includes a coating mechanism, which employs a gravure roller assembly. The gravure roller assembly is rotatable along its axis and includes an insulating adhesive coating area. The insulating adhesive coating area is a gravure anilox roller with a mesh shape of oblique lines and an angle of 40-50°.

2. The current collector insulating adhesive coating system according to claim 1, characterized in that: The gravure anilox roller has a line count of 80-200 LPI and a groove depth of 20-120 μm.

3. The current collector insulating adhesive coating system according to claim 1, characterized in that: The two ends of the gravure roller device are roller shaft ends, and the area between the roller shaft ends is a carbon slurry coating area and an insulating adhesive coating area; the width of the carbon slurry coating area is the same as the width of the carbon coating area of ​​the current collector, and the width of the insulating adhesive coating area is the same as the width of the insulating adhesive coating area of ​​the current collector.

4. The current collector insulating adhesive coating system according to claim 1, characterized in that: The coating system further includes a carbon coating slurry tank corresponding to the carbon coating slurry coating area and an insulating adhesive tank corresponding to the insulating adhesive coating area; the carbon coating slurry tank contains carbon coating slurry, which is used to apply the carbon coating slurry to the current collector carbon coating area of ​​the coating mechanism when the gravure roller device rotates; the insulating adhesive tank contains insulating adhesive, which is used to apply the insulating adhesive to the current collector insulating adhesive area of ​​the coating mechanism when the gravure roller device rotates.

5. The current collector insulating adhesive coating system according to claim 3, characterized in that: The insulating adhesive coating area is an annular raised structure on both sides of the carbon paste coating area on the roll body of the gravure roller. The width of the annular raised structure in the insulating adhesive coating area is 3-9mm. The annular raised structure can be detached or installed for use.

6. The current collector insulating adhesive coating system according to claim 1, characterized in that: The coating system further includes an unwinding mechanism, a traction mechanism, and a rewinding mechanism; one end of the coating system is the unwinding mechanism and the other end is the rewinding mechanism, and between the unwinding mechanism and the rewinding mechanism are a front coating mechanism, a back coating mechanism, and a traction mechanism that guides the various mechanisms.

7. The current collector insulating adhesive coating system according to claim 6, characterized in that: The coating system further includes a drying device, which includes a first drying device disposed after the front coating mechanism and a second drying device disposed after the reverse coating mechanism; the drying device is used to dry the passing current collector.

8. The current collector insulating adhesive coating system according to claim 3, characterized in that: The gravure roller device is equipped with several sets of carbon slurry coating areas and insulating adhesive coating areas, which can simultaneously coat the parallel coating areas of an entire sheet of uncut current collector foil.

9. The current collector insulating adhesive coating system according to claim 8, characterized in that: In the aforementioned groups of carbon slurry coating areas and insulating adhesive coating areas, each group of carbon slurry coating areas has insulating adhesive coating areas on both sides. The side of the insulating adhesive coating area away from the carbon slurry coating area has a tab blanking area. The diameter of the gravure roller body in the tab blanking area is smaller than the diameter of the gravure roller body in the carbon slurry coating area.

10. The current collector insulating adhesive coating system according to claim 6, characterized in that: The traction mechanism includes a flattening roller and a tension roller for adjusting the current collector plate shape, and the flattening roller and tension roller are selected and positioned as needed.

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