Marker and its preparation method and application

Abstract

A marker and its preparation method and application, the marker comprises a core and a coating layer, the core is a colored particle, the coating layer is an organic matter, and the organic matter is coated on the outer surface of the colored particle. The marker is used on a diaphragm, and the colored particles in the marker are easily recognized by the equipment; and the marker does not need to be posted manually, which can save labor costs; when the diaphragm contacts the electrolyte, the organic matter dissolves in the electrolyte, and the colored particles have no adhesion to the diaphragm and are peeled off from the diaphragm. During the use of the battery, the colored particles no longer block the transmission of lithium ions and have no effect on the battery performance.

Description

Technical Field

[0001] The present application relates to the technical field of battery diaphragms, and in particular to a marker and a preparation method and application thereof. Background Art

[0002] In the prior art, the battery diaphragm will be posted with a termination tape at the last few meters, so that when the battery diaphragm is used to the end, the equipment will identify the termination tape and alarm, reminding the operator to replace the new diaphragm roll in time. Currently, the termination tape is posted manually by sticking tape or inkjet, which is inefficient and affects product quality; inkjet on the surface of the diaphragm will block the diaphragm pores, resulting in increased diaphragm permeability, obstructed lithium ion transmission, increased battery impedance, and a greater impact on battery performance. Summary of the invention

[0003] The purpose of the present application is to provide a marker, a method for preparing the marker, a diaphragm and a battery, which solves the problem of adding a marker to the diaphragm of the battery without affecting the performance of the diaphragm of the battery.

[0004] To achieve the purpose of this application, this application provides the following technical solutions:

[0005] In a first aspect, the present invention provides a marker, comprising a core and a coating layer; the marker is used in a battery separator, the core comprising colored particles; the coating layer is coated on the outer surface of the core, the coating layer comprises organic matter, and the organic matter is soluble in an electrolyte.

[0006] In one embodiment, the particle size of the core is 20 nm-5 μm.

[0007] In one embodiment, the colored particles are colored dye particles.

[0008] In one embodiment, the colored dye particles include one or more of phthalocyanine blue, cobalt green, brilliant blue, isoindolinone yellow, quinacridone red, and carbon black.

[0009] In one embodiment, the coating layer has a thickness of 10 nm to 200 nm.

[0010] In one embodiment, the melting point of the organic matter is greater than or equal to 80°C.

[0011] In one embodiment, the molecular weight of the organic matter is 50-400.

[0012] In one embodiment, the organic matter includes one or more of p-toluenesulfonyl isocyanate, propylene sulfate, diphenyl carbonate, propylene sultone, propylene-1,3 sultone, triphenyl phosphate, triphenyl phosphite, and cyclopentane sulfone.

[0013] In one embodiment, the mass ratio of the colored particles to the organic matter is 10:(0.01-10000).

[0014] In a second aspect, the present invention provides a method for preparing a marker, comprising: mixing a colored particle raw material and an organic raw material according to a preset mass ratio to obtain a mixed solution; filtering the mixed solution, and cooling the mixed solution to obtain the marker. The marker comprises a core and a coating layer, wherein the coating layer is coated on the outer surface of the core, the core comprises colored particles, the coating layer comprises organic matter, and the organic matter is soluble in the electrolyte.

[0015] In a third aspect, the present invention provides a diaphragm, comprising a base film and an identification layer, wherein the identification layer is arranged on the base film, and the identification layer comprises the marker as described in any one of the first aspects; or, the identification layer comprises the marker obtained by the preparation method of the marker as described in the second aspect.

[0016] In one embodiment, the marking layer has a thickness of 50 nm-100 μm; and / or the marking layer includes a first side, and the length of the first side is 1 cm-10 cm.

[0017] In a fourth aspect, the present invention provides a method for manufacturing a diaphragm, comprising setting a marker on a base film to obtain the diaphragm; the diaphragm comprises a base film and a marking layer formed on the base film, and the marker is a marker as described in any one of the first aspects.

[0018] In a fifth aspect, the present invention provides a battery, comprising an electrolyte and the diaphragm described in any one of the third aspects, or the battery comprises a diaphragm obtained by the diaphragm manufacturing method as described in the fourth aspect, and the diaphragm is immersed in the electrolyte.

[0019] In one embodiment, the electrolyte includes the colored particles and the organic matter.

[0020] The present invention provides a marker, which includes a core and a coating layer, wherein the core is a colored particle, and the coating layer is an organic matter, and the organic matter is coated on the outer surface of the colored particle. The marker is used on the diaphragm, and the colored particles in the marker are easily recognized by the equipment; and the marker does not need to be posted manually, which can save labor costs; when the diaphragm contacts the electrolyte, the organic matter dissolves in the electrolyte, and the colored particles have no adhesion to the diaphragm and are peeled off from the diaphragm. During the use of the battery, the colored particles no longer block the transmission of lithium ions and have no effect on the battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 is a schematic diagram of a marker of an embodiment;

[0023] Figure 2 is a schematic diagram of an embodiment of a diaphragm;

[0024] Figure 3 The present invention is a flow chart of a method for preparing a marker.

[0025] Description of reference numerals:

[0026] 1-core; 2-coating layer; 3-labeling layer; 4-diaphragm, 5-base membrane, D-first side. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0029] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] The present invention provides a marker, comprising a core 1 and a coating 2; the marker is used in a separator 4 of a battery, the core 1 comprises colored particles; the coating 2 is coated on the outer surface of the core 1, and the coating 2 comprises organic matter, which is soluble in an electrolyte.

[0031] Please refer to Figure 1The present invention provides a marker, which includes a core 1 and a coating layer 2. The core 1 is a colored particle, and the coating layer 2 is an organic matter, which is coated on the outer surface of the colored particle. The marker is used on the diaphragm 4, and the colored particles in the marker are easily recognized by the equipment; and the marker does not need to be posted manually, which can save labor costs; when the diaphragm 4 contacts the electrolyte, the organic matter dissolves in the electrolyte, and the colored particles have no adhesion to the diaphragm 4 and are peeled off from the diaphragm 4. During the use of the battery, the colored particles no longer block the transmission of lithium ions and have no effect on the battery performance. The colored particles show color, and the provided color can make the marker recognized manually or by machine. The shape of the colored particles can be round, cubic and cylindrical. Optionally, the shape of the colored particles in this embodiment is round.

[0032] In one embodiment, the particle size of the core 1 is 20nm-5μm. Optionally, the particle size of the core 1 can be, but is not limited to, 20nm, 40nm, 60nm, 80nm, 100nm, 200nm, 400nm, 600nm, 800nm, 1μm, 2μm, 3μm, 4μm, 5μm. The particle size of the core 1 is the Dv50 of the core 1 particles.

[0033] When the above-mentioned range of the particle size of the kernel 1 is met, the particle size of the kernel 1 is sufficient to make the dye particles visible in the battery's diaphragm 4, which is convenient for identification during the manufacturing process; the dye particles can be evenly dispersed in the diaphragm 4 material to avoid the formation of large clumps, which helps to maintain the performance of the diaphragm 4 and does not affect the normal use of the diaphragm 4; the particles within this range will not block the pores of the diaphragm 4, and thus will not significantly affect the ion transmission efficiency of the battery. When the particle size of the kernel 1 is less than 20nm, the kernel 1 particle size is too small, which may cause the dye particles to be difficult to observe in the diaphragm 4, thereby reducing the effect of color identification; the kernel 1 particle size is too small and is prone to agglomeration, resulting in uneven dispersion in the diaphragm 4, thereby affecting the performance of the diaphragm 4; the kernel 1 with a particle size that is too small may pass through the diaphragm 4, affecting the ion transmission efficiency of the battery and reducing the performance and life of the battery. When the particle size of the core 1 is greater than 5 μm, the core 1 with a larger particle size will block the pores of the battery's diaphragm 4, affecting the ion transmission of the electrolyte, thereby reducing the battery's conductivity; the core 1 with a larger particle size will weaken the mechanical strength of the battery's diaphragm 4, causing the battery's diaphragm 4 to be more easily broken or damaged during the charge and discharge process.

[0034] In one embodiment, the colored particles include colored dye particles.

[0035] The colored dye particles serve as a part of the marker, providing visual identification function for the marker.

[0036] In one embodiment, the colored dye particles include one or more of phthalocyanine blue, cobalt green, brilliant blue, isoindolinone yellow, quinacridone red, and carbon black.

[0037] The colored dye particles can be any one of phthalocyanine blue, cobalt green, brilliant blue, isoindolinone yellow, quinacridone red, and carbon black, or a combination of any two or more of phthalocyanine blue, cobalt green, brilliant blue, isoindolinone yellow, quinacridone red, and carbon black to form a combination of different colors to meet the needs of different colors.

[0038] In one embodiment, the coating layer 2 has a thickness of 10 nm to 200 nm. Optionally, the coating layer 2 may have a thickness of, but is not limited to, 10 nm, 30 nm, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, or 200 nm.

[0039] When the thickness of the coating layer 2 is within the above range, the visibility of the colored particles can be ensured, the colored particles in the core 1 can be protected, and the color will not be excessively covered. At the same time, the coating layer 2 of appropriate thickness can form a marker of suitable size, which can be effectively attached to the battery diaphragm 4 without affecting the performance of the battery diaphragm 4. When the thickness of the coating layer 2 is less than 10nm, the coating layer 2 is too small to provide sufficient surface area for attachment; the protection is insufficient, making the dye particles more likely to fall off and unable to play the identification function; when the thickness of the coating layer 2 is greater than 200nm, the coating layer 2 is too thick, which will cause the visibility of the colored particles to decrease, making it difficult to identify on the battery diaphragm 4; the coating layer 2 that is too thick will fill the micropores on the battery diaphragm 4, affecting the mechanical properties and ion transmission efficiency of the diaphragm 4, thereby reducing the charge and discharge performance and stability of the battery.

[0040] In one embodiment, the melting point of the organic matter is greater than or equal to 80°C.

[0041] During the subsequent manufacturing process of the battery's diaphragm 4, the working temperature will be greater than 80°C during high-temperature processes such as baking, hot pressing, hot cutting, and heat sealing. Setting the melting point of the organic matter to be greater than or equal to 80°C can ensure that the organic matter remains stable at high temperatures and does not lose its structural integrity due to temperature changes, and can still play the role of identification. When the melting point of the organic matter is less than 80°C, the organic matter will soften or melt at high temperatures, causing damage to the structure of the coating layer 2, thereby losing protection for the dye particles. This causes the dye particles to be released into the battery's diaphragm 4 in advance, affecting the recognition of the marker.

[0042] In one embodiment, the molecular weight of the organic matter is 50 to 400. Optionally, the molecular weight of the organic matter may be, but is not limited to, 50, 100, 150, 200, 250, 300, 350, 400.

[0043] The molecular weight of the organic matter is within this range. The organic matter within this range usually has good solubility, which helps to ensure that the coating layer 2 can be quickly dissolved in the electrolyte, and the marker can be quickly detached from the battery's diaphragm 4, no longer blocking the transmission of lithium ions, and has no effect on the battery performance; the organic matter within this range usually has good processability and can be more easily coated during the manufacturing process of the battery's diaphragm 4, simplifying the manufacturing process and improving production efficiency; it can provide sufficient protection and adhesion. When the molecular weight of the organic matter is less than 50, the marker will easily adhere to the battery's diaphragm 4, which will block the transmission of lithium ions and affect the battery performance; organic matter with a smaller molecular weight usually has a lower mechanical strength, which will cause the coating layer 2 to be easily damaged or fall off, thereby losing the marking function; low molecular weight organic matter requires more sophisticated process control to ensure uniform coating and curing, which will increase manufacturing difficulty and cost. When the molecular weight of the organic matter is greater than 400, the solubility of the organic matter with too large a molecular weight in the electrolyte is reduced, the coating layer 2 cannot dissolve quickly in the electrolyte, and the marker is attached to the battery's diaphragm 4, which will block the transmission rate of lithium ions, thereby affecting the battery performance; organic matter with a large molecular weight has a high mechanical strength, which will cause the coating layer 2 to be too hard during the use of the battery, affecting the flexibility and pore structure of the diaphragm 4, thereby affecting the battery performance; organic matter with a large molecular weight has poor processability, which makes it difficult to evenly coat and cure the diaphragm 4 during the manufacturing process of the battery, increasing the manufacturing difficulty and cost.

[0044] In one embodiment, the organic matter includes one or more of p-toluenesulfonyl isocyanate, propylene sulfate, diphenyl carbonate, propylene sultone, propylene-1,3 sultone, triphenyl phosphate, triphenyl phosphite, and cyclopentane sulfone.

[0045] The advantage of using the above-mentioned organic matter is that it is soluble in the electrolyte. When the marker comes into contact with the electrolyte, the organic matter dissolves, and the marker can quickly detach from the battery's diaphragm 4, no longer blocking the transmission of lithium ions, and has no effect on the normal operation of the battery; it has good mechanical strength, can protect the dye particles and maintain stability during the manufacture of the diaphragm 4; it can provide adhesion to attach the marker to the battery's diaphragm 4.

[0046] In one embodiment, the mass ratio of the colored particles to the organic matter is 10:(0.01-10000). Optionally, the mass ratio of the colored particles to the organic matter may be, but is not limited to, 10:0.01, 10:0.1, 10:1, 10:10, 10:100, 10:1000, 10:10000.

[0047] The mass ratio of colored particles to organic matter within this range can ensure that the color of the marker is bright and obvious, thereby improving the visibility of the marker in the battery's diaphragm; the organic matter can provide the necessary protection to prevent damage or loss of the dye particles, and can control the dissolution rate and release mechanism of the dye particles. When the mass ratio of colored particles to organic matter is less than 10:0.01, the low proportion of organic matter will limit its functionality in controlling the release of dye particles. More organic matter is needed to ensure that the dye particles can be dissolved in a timely and effective manner; if the proportion of organic matter is too low, the dye particles cannot be effectively attached to the battery's diaphragm 4, causing the dye particles to fall off during the use of the battery, affecting the recognition; the low proportion of organic matter will make it more difficult to evenly disperse the dye particles during the manufacturing process, requiring more sophisticated process control and increasing manufacturing costs. When the mass ratio of colored particles and organic matter is greater than 10:10000, the excessively high proportion of organic matter may cause the color intensity of the dye particles to weaken, thereby reducing the visibility of the color of the marker in the battery's diaphragm; the excessively high proportion of organic matter limits its functionality in controlling the release of dye particles; the excessively high proportion of organic matter will make it more difficult to evenly coat and solidify the organic matter during the manufacturing process, thereby increasing manufacturing costs.

[0048] In one embodiment, the present invention provides a method for preparing a marker, please refer to Figure 3 , and its preparation method comprises the following steps:

[0049] Step S1, mixing a colored particle raw material and an organic raw material to obtain a mixed liquid.

[0050] Step S2, filtering the mixed solution and cooling it to obtain the marker.

[0051] Specifically, in step S1, the colored particle raw material and the organic raw material are mixed to obtain a mixed liquid, including: under an inert atmosphere, the colored particle raw material is uniformly dispersed in the molten organic raw material to form a mixed liquid; the obtained mixed liquid is filtered and cooled in liquid nitrogen to obtain organic solid particles of a certain size wrapped with colored particles.

[0052] In one embodiment, the present invention provides a diaphragm 4, which includes a base film 5 and an identification layer 3, wherein the identification layer 3 is disposed on the base film 5, and the identification layer 3 includes a marker as in any one of the above embodiments; or, the identification layer 3 includes a marker obtained by a preparation method of a marker in one embodiment.

[0053] Please refer to Figure 2The identification layer 3 includes a marker, and the identification layer 3 is arranged on the base film 5. A colored identification area can be formed on the diaphragm 4, and the identification layer 3 can be identified. The identification layer 3 is arranged at the tail end of the diaphragm 4. When the diaphragm 4 is used to the tail end, the diaphragm 4 needs to be replaced. The identification instrument recognizes the identification layer 3 and an alarm is issued to remind the preparation of changing the roll of the diaphragm 4. The setting method of the identification layer 3 on the base film 5 can be electrostatic powder spraying, physical vapor deposition, lamination, liquid spraying and thermal spraying. Optionally, in this embodiment, electrostatic powder spraying is used.

[0054] In order to achieve good ionic conductivity and electronic insulation, a functional coating is also applied on the base film 5 of the diaphragm 4 so that the diaphragm 4 meets the performance requirements; after the functional coating is applied on the base film 5, an identification layer 3 is set on the functional coating to form a colored identification area for identification.

[0055] In one embodiment, the marking layer 3 has a thickness of 50 nm-100 μm; and / or the marking layer 3 includes a first side, and the length of the first side is 1 cm-10 cm.

[0056] The thickness of the identification layer 3 can be, but is not limited to, 50nm, 200nm, 400nm, 600nm, 800nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 20μm, 40μm, 60μm, 80μm, and 100μm. The thickness of the identification layer 3 is within this range, which can provide good recognition during use; the performance and reliability of the identification layer 3 can be guaranteed; the production process of the identification layer 3 with a moderate thickness is simple, which can reduce production costs. When the thickness of the identification layer 3 is less than 50nm, the identification layer 3 is too thin, which will result in the color not being obvious enough, making it more difficult to identify; the identification layer 3 that is too thin is easily affected by the external environment, which will cause the identification layer 3 to be damaged or peeled off, reducing its durability and durability during use. When the thickness of the identification layer 3 is greater than 10 μm, an excessively thick identification layer 3 will increase the thickness of the diaphragm 4, affecting the performance of the diaphragm 4 and reducing the performance of the battery; an excessively thick identification layer 3 will increase the amount of material used, resulting in an increase in cost. Figure 2 , the first side D is the width of the identification layer 3 on the membrane along the direction of membrane winding. The length of the first side can be, but is not limited to, 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm. The length of the first side within this range can provide a sufficient recognition area to ensure the recognition of the identification layer 3. When the length of the first side is less than 1 cm, it cannot provide a sufficient recognition area, and the recognition machine cannot recognize it quickly; when the length of the first side is greater than 10 cm, the amount of material used will increase, resulting in an increase in cost, while introducing more unnecessary organic matter and colored particles.

[0057] In one embodiment, the present invention provides a method for manufacturing a diaphragm, and the manufacturing method comprises the following steps:

[0058] Step S10, setting a marker on the base film to obtain the diaphragm.

[0059] Specifically, in step S10, the marker is set on the base film, including: loading dry marker powder into a powder storage tank of a solid powder electrostatic spraying system, starting the electrostatic spraying system, electrostatically spraying the marker powder onto the base film 5, and letting it stand to obtain a diaphragm.

[0060] Among them, the parameter setting of the electrostatic spraying system is that the spraying amount is 0.01g / min-200g / min. Optionally, the spraying amount can be but not limited to 0.01g / min, 1g / min, 10g / min, 50g / min, 100g / min, 150g / min, and 200g / min.

[0061] The moving speed of the base film is 1m / min-500m / min. Optionally, the moving speed of the base film can be but not limited to 1m / min, 10m / min, 50m / min, 100m / min, 200m / min, 300m / min, 400m / min, 500m / min.

[0062] The spraying distance of the electrostatic spraying system is 5cm-50cm. Optionally, the spraying distance of the electrostatic spraying system can be but not limited to 5cm, 10cm, 20cm, 30cm, 40cm, and 50cm.

[0063] The spraying voltage of the electrostatic spraying system is 10kv-30kv. Optionally, the spraying voltage of the electrostatic spraying system can be but not limited to 10kv, 15kv, 20kv, 25kv, and 30kv.

[0064] The manual posting method requires the wrinkled part of the membrane to be uncovered and re-posted, and during the posting process, it is necessary to constantly confirm whether the posting is straight, which has low posting efficiency; this easily causes wrinkles in the tape, thereby causing fold defects in the membrane 4, affecting the quality of the membrane 4. The electrostatic spraying method provided by the present invention eliminates the need for manual posting, saves labor costs, has high efficiency, and has a good effect of electrostatic spraying, and the formed identification layer is smooth and uniform.

[0065] In one embodiment, the present invention provides a battery, which includes an electrolyte and a separator 4 as in the above embodiment, wherein the separator 4 is immersed in the electrolyte.

[0066] The separator 4 is rolled up and immersed in an electrolyte to form a battery. The battery can be a lithium ion battery or a sodium ion battery.

[0067] In one embodiment, the electrolyte includes colored particles and organic matter.

[0068] When the diaphragm 4 comes into contact with the electrolyte, the organic matter dissolves in the electrolyte, and the colored particles have no adhesion to the diaphragm 4 and are peeled off from the diaphragm 4 and enter the electrolyte; and during the operation of the lithium battery, the colored particles will not block the transmission of lithium ions and have no effect on the battery performance.

[0069] The technical solution of the present invention is described in detail below through specific embodiments.

[0070] Example 1

[0071] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0072] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1:10.

[0073] The method for making the diaphragm provided in this embodiment is as follows:

[0074] (1) Under nitrogen atmosphere, add 10 g of phthalocyanine blue to 100 ml of molten vinyl sulfate to obtain a mixed solution.

[0075] (2) The mixed solution obtained in step (1) was stirred for 2 h, poured into liquid nitrogen covered with a 2-μm pore size sieve, and cooled for 2 h to obtain a marker.

[0076] (3) Drying the marker obtained in step (2).

[0077] (4) The dried marker is placed in the powder storage tank of the solid powder electrostatic spraying system.

[0078] (5) Start the electrostatic spraying system, where the parameters are set to 300 g / min, turn on the spray gun and reel in the base film at a speed of 300 m / min, set the spraying distance to 5 cm, and the spraying voltage to 25 kV.

[0079] (6) Allow to stand to obtain a diaphragm.

[0080] On the obtained separator, the thickness of the marking layer was 100 nm, and the length of the first side of the marking layer on the separator was 1.5 cm.

[0081] Example 2

[0082] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (cobalt green colored particles) and a coating layer (vinyl sulfate).

[0083] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of cobalt green to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the identification layer is 100 nm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0084] The method for making the diaphragm in Example 2 is the same as that in Example 1.

[0085] The difference between Example 2 and Example 1 is that the material of the colored particles is changed.

[0086] Example 3

[0087] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0088] The particle size of the core is 20 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0089] The method for making the diaphragm in Example 3 is the same as that in Example 1.

[0090] The difference between Example 3 and Example 1 is that the particle size of the colored particles is changed.

[0091] Example 4

[0092] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0093] The particle size of the core is 5 μm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0094] The method for making the diaphragm in Example 4 is the same as that in Example 1.

[0095] The difference between Example 4 and Example 1 is that the particle size of the colored particles is changed.

[0096] Example 5

[0097] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0098] The particle size of the core is 300 nm, the thickness of the coating layer is 10 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0099] The method for making the diaphragm in Example 5 is the same as that in Example 1.

[0100] The difference between Example 5 and Example 1 is that the thickness of the organic coating layer is changed.

[0101] Example 6

[0102] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0103] The particle size of the core is 300 nm, the thickness of the coating layer is 200 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the identification layer is 100 nm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0104] The method for making the diaphragm in Example 6 is the same as that in Example 1.

[0105] The difference between Example 6 and Example 1 is that the thickness of the organic coating layer is changed.

[0106] Example 7

[0107] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking object, and the marking object includes a core (phthalocyanine blue colored particles) and a coating layer (polyethylene).

[0108] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of polyethylene is greater than 3000, and the mass ratio of phthalocyanine blue to polyethylene is 1: 10. On the obtained diaphragm, the thickness of the identification layer is 100 nm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0109] The method for making the diaphragm in Example 7 is the same as that in Example 1.

[0110] The difference between Example 7 and Example 1 is that the organic material is changed.

[0111] Example 8

[0112] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (methylene disulfonate).

[0113] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of methylene disulfonate is 188, and the mass ratio of phthalocyanine blue to methylene disulfonate is 1: 10. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0114] The method for making the diaphragm in Example 8 is the same as that in Example 1.

[0115] The difference between Example 8 and Example 1 is that the organic material is changed.

[0116] Example 9

[0117] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0118] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 10:0.01. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0119] The method for making the diaphragm in Example 9 is the same as that in Example 1.

[0120] The difference between Example 9 and Example 1 is that the mass ratio of the colored particles and the organic matter is changed.

[0121] Example 10

[0122] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0123] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 10: 10000. On the obtained diaphragm, the thickness of the marking layer is 100 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0124] The method for making the diaphragm in Example 10 is the same as that in Example 1.

[0125] The difference between Example 10 and Example 1 is that the mass ratio of the colored particles and the organic matter is changed.

[0126] Embodiment 11

[0127] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0128] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the marking layer is 50 nm, and the length of the first side of the marking layer on the diaphragm is 1.5 cm.

[0129] The method for making the diaphragm in Example 11 is the same as that in Example 1.

[0130] The difference between Example 11 and Example 1 is that the thickness of the marking layer is changed.

[0131] Example 12

[0132] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0133] The particle size of the core is 300 nm, the thickness of the coating layer is 50 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of phthalocyanine blue to vinyl sulfate is 1: 10. On the obtained diaphragm, the thickness of the identification layer is 100 μm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0134] The method for making the diaphragm in Example 12 is the same as that in Example 1.

[0135] The difference between Example 12 and Example 1 is that the thickness of the identification layer is changed.

[0136] Embodiment 13

[0137] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking material, and the marking material includes a core (phthalocyanine blue colored particles) and a coating layer (vinyl sulfate).

[0138] The particle size of the core is 300 nm, the thickness of the coating layer is 55 nm, the molecular weight of vinyl sulfate is 124, and the mass ratio of the core to vinyl sulfate is 1:10.

[0139] The method for making the diaphragm provided in this embodiment is as follows:

[0140] (1) Under a nitrogen atmosphere, 10 g of phthalocyanine blue and 2 g of vinyl sulfate were dispersed in an aqueous solution to obtain a mixed solution.

[0141] (2) The mixed solution obtained in step (1) is stirred for 2 h, and the solution is spray-dried to obtain a marker.

[0142] (3) The dried marker is placed in the powder storage tank of the solid powder electrostatic spraying system.

[0143] (4) Start the electrostatic spraying system, where the parameters are set to 300 g / min, turn on the spray gun and reel in the base film at a speed of 300 m / min, set the spraying distance to 5 cm, and the spraying voltage to 25 kV.

[0144] (5) Allow to stand to obtain a diaphragm.

[0145] On the obtained separator, the thickness of the marking layer was 100 nm, and the length of the first side of the marking layer on the separator was 1.5 cm.

[0146] The difference between Example 13 and Example 1 is that the method for manufacturing the diaphragm in Example 13 is different from that in Example 1.

[0147] Comparative Example 1

[0148] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is disposed on the base film.

[0149] The identification layer is formed by sticking the tape on the base film, the thickness of the identification layer is 50 μm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0150] The difference between Comparative Example 1 and Example 1 is that the identification layer is formed by sticking with an adhesive tape.

[0151] Comparative Example 2

[0152] This embodiment provides a diaphragm, which includes a base film and a marking layer, wherein the marking layer is arranged on the base film, the marking layer includes a marking object, and the marking object includes a core (phthalocyanine blue colored particles).

[0153] The particle size of the core is 300 nm. On the obtained diaphragm, the thickness of the identification layer is 50 μm, and the length of the first side of the identification layer on the diaphragm is 1.5 cm.

[0154] The method for preparing the diaphragm in Comparative Example 2 is the same as that in Example 1.

[0155] The difference between Comparative Example 2 and Example 1 is that the marker consists only of colored particles.

[0156] The separators provided by Examples 1-13 and Comparative Examples 1-2 were tested.

[0157] Test method:

[0158] (1) Test of air permeability increase

[0159] Refer to the test method for air permeability in GB / T 36363-2018 "Polyolefin separators for lithium-ion batteries".

[0160] Cut three pieces of diaphragm at a distance of 150 mm from each other in the longitudinal direction, with the sample size being 100 mm × 100 mm. Place the sampled diaphragm in the test head of a permeability tester suitable for the test range for air permeability test, and take the average of the three test results as the air permeability of the diaphragm.

[0161] (2) Test of ionic conductivity

[0162] Refer to the test method for ionic conductivity in GB / T 36363-2018 "Polyolefin separators for lithium-ion batteries".

[0163] Cut 4 diaphragms that match the electrode test mold, put the diaphragms into 1.0 mol / L lithium hexafluorophosphate, and an electrolyte with a volume ratio of 1:1:1 of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate, keep it sealed, and soak for 2 hours. Inject the electrolyte into the resistance test mold, put in 1 layer of diaphragms in turn, test its AC impedance resistance, then put in 1 layer, test its AC impedance resistance, until 4 layers are put in, and measure the four AC impedance resistances R1, R2, R3, and R4 respectively. During the test, ensure that the electrolyte in the resistance test module can completely immerse the placed diaphragms.

[0164]

[0165] Where σ is the ionic conductivity of the membrane, d is the membrane thickness, R is the membrane resistance, and s is the cut membrane area.

[0166] Table 1

[0167]

[0168]

[0169] By comparing Example 2 with Example 1, since only the material of the colored particles is changed, there is no significant change in the air permeability increment and ionic conductivity.

[0170] By comparing Example 3 with Example 1, the air permeability increment of Example 3 is higher than that of Example 1, and the ion conductivity is lower than that of Example 1. This is because the colored particles with small particle sizes agglomerate, resulting in uneven dispersion in the diaphragm, thereby affecting the performance of the diaphragm.

[0171] By comparing Example 4 with Example 1, Example 4 has a higher air permeability increment than Example 1, and a lower ion conductivity than Example 1. This is because the colored particles with larger particle sizes will block the pores of the battery's diaphragm and affect the ion transport of the electrolyte.

[0172] By comparing Example 5 with Example 1, the air permeability increment of Example 5 is higher than that of Example 1, and the ion conductivity is lower than that of Example 1. This is because the thickness of the organic coating layer is small, which affects the performance of the diaphragm.

[0173] Comparing Example 6 with Example 1, the air permeability increment of Example 6 is higher than that of Example 1, and the ion conductivity is lower than that of Example 1. This is because the thickness of the organic coating layer is large, and an excessively thick coating layer will fill the micropores on the battery's diaphragm, affecting the mechanical properties of the diaphragm and the ion transmission efficiency.

[0174] By comparing Example 7 with Example 1, the air permeability increment of Example 7 is higher than that of Example 1, and the ion conductivity is lower than that of Example 1. This is because the solubility of organic matter with too large a molecular weight in the electrolyte is reduced, the coating layer cannot be quickly dissolved in the electrolyte, and the marker is attached to the battery diaphragm, which blocks the transmission of lithium ions and affects the ion conductivity and permeability.

[0175] By comparing Example 8 with Example 1, the air permeability increment and ion conductivity of Example 8 are not much different from those of Example 1, because only the organic material is changed and the organic material meets the standard.

[0176] By comparing Example 9 and Example 10 with Example 1, the permeability increment of Example 9 and Example 10 is higher than that of Example 1, and the ionic conductivity is lower than that of Example 1. This is because if the mass ratio of the colored fuel particles is too high or too low, the colored particles will not be able to smoothly enter the electrolyte, and will remain on the diaphragm, affecting the ionic conductivity and permeability of the diaphragm.

[0177] Comparing Example 11 with Example 1, the air permeability increment and ion conductivity of Example 11 are not much different from those of Example 1. This is because the identification layer is too thin and has no substantial effect on the diaphragm.

[0178] Compared with Example 1, Example 12 has a higher air permeability increment and a lower ion conductivity than Example 1. This is because the identification layer is too thick, which affects the air permeability increment and ion conductivity of the diaphragm.

[0179] Compared with Example 1, Example 13 has a higher air permeability increment than Example 1, and a lower ionic conductivity than Example 1. The example adopts a mixture of colored dye particles and organic matter in an aqueous solution, which results in a poor coating effect of the organic matter, affecting the air permeability increment and ionic conductivity of the diaphragm.

[0180] Comparing Comparative Example 1 with Example 1, Comparative Example 1 uses tape to stick on the base membrane, and the air permeability increment and ion conductivity performance of Comparative Example 1 cannot be measured. This is because the tape has a great impact on the base membrane and the tape will directly block the base membrane. Traditionally, tape is used as a marker. When the base membrane with tape is rolled into the battery, it has a great impact on the battery performance.

[0181] Comparing Comparative Example 2 with Example 1, Comparative Example 2 uses only colored particles without using organic matter, which has a great impact on the base membrane. The colored particles block the base membrane, resulting in a high air permeability increment and poor ion conductivity performance of Comparative Example 2.

[0182] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0183] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiment and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A marker for use in a battery separator, characterized in that: include: the inner core, including the colored particles; The coating layer is coated on the outer surface of the inner core, and the coating layer includes organic matter, and the organic matter is soluble in the electrolyte.

2. The marker according to claim 1, characterized in that: The particle size of the core is 20nm-5μm.

3. The marker according to claim 1, characterized in that: The colored particles are colored dye particles.

4. The marker according to claim 3, characterized in that: The colored dye particles include one or more of phthalocyanine blue, cobalt green, brilliant blue, isoindolinone yellow, quinacridone red, and carbon black.

5. The marker according to claim 1, characterized in that: The coating layer has a thickness of 10 nm to 200 nm.

6. The marker according to claim 1, characterized in that: The melting point of the organic matter is greater than or equal to 80°C.

7. The marker according to claim 1, characterized in that: The molecular weight of the organic matter is 50-400.

8. The marker according to claim 1, characterized in that: The organic matter includes one or more of p-toluenesulfonyl isocyanate, propylene sulfate, diphenyl carbonate, propylene sultone, propylene-1,3 sultone, triphenyl phosphate, triphenyl phosphite, and cyclopentane sulfone.

9. The marker according to claim 1, characterized in that: The mass ratio of the colored particles to the organic matter is 10:(0.01-10000).

10. A method for preparing a marker, characterized in that: include: Mixing the colored particle raw material and the organic raw material in proportion to obtain a mixed liquid; Filtering the mixed solution and cooling it to obtain the marker; Wherein, the marker comprises a core and a coating layer, wherein the coating layer is coated on the outer surface of the core, the core comprises colored particles, and the coating layer comprises organic matter, and the organic matter is soluble in the electrolyte.

11. A diaphragm, characterized in that: It comprises a base film and a marking layer, wherein the marking layer is arranged on the base film, and the marking layer comprises the marking object according to any one of claims 1 to 9; or, the marking layer comprises the marking object obtained by the method for preparing the marking object according to claim 10.

12. The diaphragm according to claim 11, characterized in that The thickness of the identification layer is 50 nm-100 μm; and / or, in the winding direction of the diaphragm, the identification layer includes a first side, and the length of the first side is 1 cm-10 cm.

13. A method for manufacturing a diaphragm, characterized in that: include: placing a marker on the base film to obtain the diaphragm; The diaphragm includes a base film and a marking layer formed on the base film, and the marking object is the marking object according to any one of claims 1 to 9.

14. A battery, characterized in that: The battery comprises an electrolyte and the diaphragm as described in claims 11-12; or, the battery comprises a diaphragm obtained by the diaphragm manufacturing method as described in claim 13; and the diaphragm is immersed in the electrolyte.

15. The battery according to claim 14, characterized in that The electrolyte includes the colored particles and the organic matter.

Images