Flame-retardant composite current collector and preparation method thereof
By using MoS2 nanowires and ammonium polyphosphate core-shell structured flame-retardant wires in the composite current collector, a dense physical barrier and a porous carbon layer are formed, which solves the problem of thermal runaway in large battery cells and improves the safety performance of the battery.
Patent Information
- Application Number
- CN202510964423.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-17
AI Technical Summary
Existing composite current collectors cannot effectively prevent thermal runaway in large battery cells, resulting in insufficient battery safety.
MoS2 nanowires and ammonium polyphosphate are used to make flame-retardant wires with a core-shell structure. A mesh spacer and a metal layer are combined to form a flame-retardant composite current collector. The ammonium polyphosphate is adsorbed on the MoS2 surface through electrostatic action to form a dense physical barrier and generate polyphosphoric acid and ammonia at high temperature, which synergistically form a porous carbon layer to isolate heat and combustible gases.
It releases flame-retardant gas in the event of thermal runaway, maintains conductivity, improves battery safety, effectively blocks heat transfer and diffusion of combustible gas, inhibits oxygen penetration, and improves battery safety.
Smart Images
Figure CN120809830A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of batteries, in particular to a flame-retardant composite current collector and a preparation method. BACKGROUND
[0002] At present, there are still phenomena of electric vehicle self-ignition in the society, the state also attaches great importance to the field of new energy electric vehicles, and the downstream battery industry also attaches great importance to improving the safety of batteries. Composite current collectors appear in the market, which can improve the energy density and safety performance. However, the composite aluminum applied in low-capacity batteries can pass through the puncture, but the composite current collector in large battery cells cannot effectively block thermal runaway. SUMMARY
[0003] In view of the problems existing in the prior art flame-retardant composite current collector and preparation method, the present application is proposed.
[0004] Therefore, one object of the present application is to provide a flame-retardant composite current collector, which aims to provide a composite current collector that can effectively block thermal runaway.
[0005] To solve the above technical problems, the present application provides the following technical scheme: a flame-retardant composite current collector, comprising,
[0006] a polymer film layer;
[0007] a metal layer arranged on the surface of the polymer film layer;
[0008] a flame-retardant layer arranged on the surface of the metal layer, which comprises a plurality of metal blocks, a reticular interval arranged between the metal blocks, and a flame-retardant line arranged inside the reticular interval.
[0009] As a preferred scheme of the flame-retardant composite current collector of the present application, the flame-retardant line adopts a core-shell structure made of MoS2 nanowire and ammonium polyphosphate.
[0010] The core-shell structure of the flame-retardant line is formed by adsorbing ammonium polyphosphate on the surface of MoS2.
[0011] As a preferred scheme of the flame-retardant composite current collector of the present application, the flame-retardant line adopts a core-shell structure made of MoS2 nanowire and ammonium polyphosphate.
[0012] The core-shell structure of the flame-retardant line is formed by adsorbing MoS2 on the surface of ammonium polyphosphate.
[0013] As a preferred scheme of the flame-retardant composite current collector of the present application, the metal block is any one of a rhombus, a circle, a square, a polygon, or an ellipse.
[0014] As a preferred scheme of the fire-retardant composite current collector, the plurality of metal blocks include complete blocks not connected with the metal layer boundary and residual blocks connected with the metal layer boundary, and the residual blocks are cut from the complete blocks according to the shape of the complete blocks through the metal layer boundary line.
[0015] The plurality of complete blocks and the residual blocks are arranged in equal meshed intervals on the surface of the metal layer.
[0016] As a preferred scheme of the fire-retardant composite current collector, the thickness of the metal layer is 30-80 nm.
[0017] As a preferred scheme of the fire-retardant composite current collector, the thickness of the metal blocks is 500-1000 nm.
[0018] As a preferred scheme of the fire-retardant composite current collector, the width of the meshed intervals is 5-50 μm.
[0019] The fire-retardant composite current collector has the beneficial effect of releasing fire-retardant gas and maintaining electrical conductivity in thermal runaway, thereby improving the safety performance of the battery.
[0020] Another object of the present application is to provide a preparation method of a fire-retardant composite current collector, which aims to prepare a composite current collector effective in blocking thermal runaway.
[0021] To solve the above technical problems, the present application provides the following technical scheme: a preparation method of a fire-retardant composite current collector, comprising;
[0022] evaporating a metal layer with a thickness of 30-80 nm on the surface of the polymer film;
[0023] evaporating a plurality of metal blocks with a thickness of 500-1000 nm on the surface of the metal layer, and forming meshed intervals with a width of 5-50 μm between the plurality of metal blocks;
[0024] preparing a nano fire-retardant powder with a core-shell structure by combining MoS2 nanowires with ammonium polyphosphate;
[0025] shielding the surface of the metal blocks, and spraying the fire-retardant powder into the meshed intervals;
[0026] pressing the nano fire-retardant powder in the meshed intervals by a rubber roller to form fire-retardant lines.
[0027] As a preferred scheme of the preparation method of the fire-retardant composite current collector, the surface of MoS2 is positively charged by treating MoS2 nanosheets with cetyltrimethylammonium bromide;
[0028] The surface of ammonium polyphosphate is negatively charged by dispersing ammonium polyphosphate in water and adjusting the pH to alkaline.
[0029] Mixing and stirring, adsorbing ammonium polyphosphate on the surface of MoS2 by electrostatic effect to form core-shell structure, or adsorbing MoS2 on the surface of ammonium polyphosphate to form core-shell structure;
[0030] After centrifugal washing of the core-shell structure formed by MoS2 and ammonium polyphosphate, the nanometer flame-retardant powder is formed by vacuum oven drying and solidification.
[0031] The beneficial effects of the present application: the composite current collector formed by MoS2 nanowire and ammonium polyphosphate flame-retardant wire, MoS2 has a two-dimensional layered structure similar to graphene, when burning, MoS2 lamella is arranged on the surface of the material, forming a dense physical barrier, effectively blocking heat transfer and combustible gas diffusion (such as CO, CH4, etc.), while inhibiting oxygen permeation, ammonium polyphosphate decomposes to generate polyphosphoric acid and ammonia at high temperature, promoting the system to expand and foam, and forming a porous carbon layer (expansion carbon layer) with MoS2, further isolating heat / mass exchange, and improving the safety performance of the battery. BRIEF DESCRIPTION OF DRAWINGS
[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0033] Figure 1 The overall schematic diagram of the flame-retardant composite current collector is shown;
[0034] Figure 2 The mesh spacing schematic diagram of the flame-retardant composite current collector is shown. DETAILED DESCRIPTION
[0035] In order to make those skilled in the art better understand the present application, the present application will be further described in detail below in combination with specific embodiments and drawings.
[0036] The terms used in the present application are those general terms currently widely used in the art in consideration of the functions about the present application, but these terms can be changed according to the intention of those skilled in the art, precedents or new technologies in the art. In addition, specific terms can be selected by the applicant, and in this case, the detailed meaning thereof will be described in the detailed description of the present application. Therefore, the terms used in the specification should not be understood as mere names, but based on the meaning of the terms and the overall description of the present application.
[0037] Example 1, refer to Figure 1 , the first embodiment of the present application provides a flame-retardant composite current collector, which comprises;
[0038] A high polymer film layer 100 formed by a high polymer material such as PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PETG (glycol modified PET) or PCT (polycyclohexylene dimethylene terephthalate).
[0039] A metal layer 200 disposed on the surface of the high polymer film layer 100, wherein the metal layer 200 is formed by a metal such as copper, aluminum, nickel, titanium or silver.
[0040] A flame-retardant layer 300 disposed on the surface of the metal layer 200, which includes a plurality of metal blocks 301, a reticular interval a disposed between the metal blocks 301, and a flame-retardant line 302 disposed inside the reticular interval a.
[0041] The metal blocks 301 are formed by a metal such as copper, aluminum, nickel, titanium or silver, and the metal blocks 301 are in the shape of a rhombus, a circle, a square, a polygon or an ellipse; the flame-retardant line 302 is made of Exolit AP462 (a high-quality halogen-free flame retardant of ammonium polyphosphate produced by Clariant).
[0042] Embodiment 2, with reference to Figure 1 As a second embodiment of the present application, the difference between this embodiment and the first embodiment is that the high polymer film layer 100 is formed by PET (polyethylene terephthalate); the metal layer 200 and the metal blocks 301 are formed by aluminum, and the flame-retardant line 302 is made of a core-shell structure of MoS2 nanowires and ammonium polyphosphate.
[0043] The core-shell structure of the flame-retardant line 302 is formed by ammonium polyphosphate adsorbed on the surface of MoS2 or the core-shell structure of the flame-retardant line 302 is formed by MoS2 adsorbed on the surface of ammonium polyphosphate, wherein the ammonium polyphosphate is also referred to as APP.
[0044] APP (ammonium polyphosphate) as the core: APP (ammonium polyphosphate) is decomposed by heat to generate polyphosphoric acid and ammonia, and the polyphosphoric acid promotes the formation of a carbon layer, and the ammonia dilutes oxygen and combustible gas.
[0045] MoS2 as the shell: plays the following roles: 1. catalyzing graphitization of the carbon layer: the high-temperature decomposition products of MoS2 (such as MoO3 and SO2) can catalyze the carbon layer to form a more stable graphitized structure, thereby enhancing the barrier effect; 2. free radical capture: the sulfur-containing species (such as SO2) produced by the decomposition of MoS2 can capture free radicals (H·, OH·) in the combustion chain reaction; 3. physical barrier: the lamellar structure of MoS2 delays the heat and mass transfer.
[0046] Or the core-shell structure of the flame-retardant line 302 is formed by MoS2 adsorbed on the surface of APP (ammonium polyphosphate).
[0047] MoS2 as the core: mainly rely on its physical barrier and catalytic effect of the sheet, but APP (ammonium polyphosphate) coverage may limit the direct contact of MoS2 with the flame, weaken its catalytic effect;
[0048] APP (ammonium polyphosphate) as the shell: the gas phase flame retardant produced by rapid decomposition dominates, but the condensed phase carbon layer may lack the stability of uniform dispersion of MoS2.
[0049] Further, the metal block 301 is rhombic, and the plurality of metal blocks 301 include a complete block 301a not connected with the boundary of the metal layer 200, and a residual block 301b connected with the boundary of the metal layer 200, the shape of the residual block 301b is cut according to the shape of the complete block 301a through the boundary line of the metal layer 200;
[0050] The plurality of complete blocks 301a and the plurality of residual blocks 301b are evenly spaced on the surface of the metal layer 200.
[0051] In some cases, the residual block 301b connected with the boundary of the metal layer 200, the complete block 301a reaches the boundary, that is, the cutting area is 0, at this time, the 301b can be regarded as the same as the 301a.
[0052] Further, the thickness of the metal layer 200 is 30-80nm, the thickness of the metal block 301 is 800-1000nm, and the width of the net-shaped interval a is 40μm.
[0053] The grid structure of the net-shaped interval a imitates the spider web and other natural materials, and can disperse energy through the slip between fibers and nodes when heated or stressed, avoiding brittle fracture.
[0054] The remaining structure is the same as that of example 1.
[0055] Example 3 is a third embodiment of the present application, which provides a preparation method of a flame-retardant composite current collector, the method comprising:
[0056] A metal layer 200 of 30-80nm is evaporated on the surface of the polymer film, wherein the polymer film is formed by PET (polyethylene terephthalate), and the metal layer 200 is formed by aluminum.
[0057] A plurality of metal blocks 301 with a thickness of 900nm are evaporated on the surface of the metal layer 200, and a net-shaped interval a with a width of 40μm is formed between the plurality of metal blocks 301, and the metal block 301 is made of aluminum.
[0058] The MoS2 nanosheet (prepared by liquid phase exfoliation method) is treated with cetyltrimethylammonium bromide to make the surface positively charged, 1.2 mol / L APP (ammonium polyphosphate) is dispersed in water, the pH is adjusted to alkaline, and the APP (ammonium polyphosphate) surface is negatively charged (-PO4 3- ), the two are mixed and stirred, the APP (ammonium polyphosphate) is adsorbed on the MoS2 surface by electrostatic action to form a core-shell structure, and after centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form a nano flame-retardant powder.
[0059] The surface of the metal block 301 is shielded, the flame-retardant line 302 powder is sprayed inside the mesh spacing a, and the MoS2 / APP powder is charged by electrostatic spraying and then adsorbed inside the mesh spacing a on the grounded current collector.
[0060] Finally, the nano flame-retardant powder inside the mesh spacing a is pressed by a rubber roller to form the flame-retardant line 302, the hot pressing temperature is 65°C, and the thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0061] Example 4 is the fourth embodiment of the present application, which provides a preparation method of a flame-retardant composite current collector, the method comprising:
[0062] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of the polymer film, wherein the polymer film is formed of PET (polyethylene terephthalate), and the metal layer 200 is formed of aluminum.
[0063] A plurality of metal blocks 301 with a thickness of 500 nm are evaporated on the surface of the metal layer 200, and a mesh spacing a with a width of 40 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0064] The MoS2 nanosheet (prepared by liquid phase exfoliation method) is treated with cetyltrimethylammonium bromide to make the surface positively charged, 1.2 mol / L APP (ammonium polyphosphate) is dispersed in water, the pH is adjusted to alkaline, and the APP (ammonium polyphosphate) surface is negatively charged (-PO4 3- ), the two are mixed and stirred, the APP (ammonium polyphosphate) is adsorbed on the MoS2 surface by electrostatic action to form a core-shell structure, and after centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form a nano flame-retardant powder.
[0065] The surface of the metal block 301 is shielded, the flame-retardant line 302 powder is sprayed inside the mesh spacing a, and the MoS2 / APP powder is charged by electrostatic spraying and then adsorbed inside the mesh spacing a on the grounded current collector.
[0066] Finally, the nanometer flame-retardant powder in the net-shaped interval a is pressed by a rubber roller to form the flame-retardant line 302, and the hot-pressing temperature is 65°C. The thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0067] Embodiment 5 provides a preparation method of the flame-retardant composite current collector, and the method comprises the following steps of:
[0068] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of the polymer film, wherein the polymer film is formed by PET (polyethylene terephthalate), and the metal layer 200 is formed by aluminum.
[0069] A plurality of metal blocks 301 with a thickness of 900 nm are evaporated on the surface of the metal layer 200, and a net-shaped interval a with a width of 40 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0070] The MoS2 nanosheet (prepared by a liquid-phase exfoliation method) is treated by cetyltrimethylammonium bromide to make the surface of the MoS2 nanosheet positively charged. APP (ammonium polyphosphate) with a concentration of 1.2 mol / L is dispersed in water, and the pH is adjusted to be alkaline, preferably pH = 10, so that the surface of the APP (ammonium polyphosphate) is negatively charged (-PO4 3- ). The two are mixed and stirred, and the APP (ammonium polyphosphate) is adsorbed on the surface of the MoS2 by electrostatic action to form a core-shell structure. After centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form the nanometer flame-retardant powder.
[0071] The surface of the metal block 301 is shielded, and the flame-retardant line 302 powder is sprayed in the net-shaped interval a. The MoS2 / APP powder is charged by electrostatic spraying and then adsorbed in the net-shaped interval a of the grounded current collector.
[0072] Finally, the nanometer flame-retardant powder in the net-shaped interval a is pressed by a rubber roller to form the flame-retardant line 302, and the hot-pressing temperature is 65°C. The thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0073] Embodiment 6 provides a preparation method of the flame-retardant composite current collector, and the method comprises the following steps of:
[0074] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of the polymer film, wherein the polymer film is formed by PET (polyethylene terephthalate), and the metal layer 200 is formed by aluminum.
[0075] A plurality of metal blocks 301 with a thickness of 900 nm are evaporated on the surface of the metal layer 200, and a net-shaped interval a with a width of 40 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0076] The MoS2 nanosheet (prepared by liquid phase exfoliation method) is treated with cetyltrimethylammonium bromide to make its surface positively charged, 0.8 mol / L APP (ammonium polyphosphate) is dispersed in water, the pH is adjusted to alkaline, preferably pH = 10, and the surface of APP (ammonium polyphosphate) is negatively charged (-PO4 3- ), the two are mixed and stirred, APP (ammonium polyphosphate) is adsorbed on the surface of MoS2 by electrostatic action to form a core-shell structure, and after centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form a nano flame-retardant powder.
[0077] The surface of the metal block 301 is shielded, and the flame-retardant line 302 powder is sprayed inside the mesh spacing a, and the MoS2 / APP powder is charged by electrostatic spraying and then adsorbed inside the mesh spacing a on the grounded current collector.
[0078] Finally, the nano flame-retardant powder inside the mesh spacing a is pressed by a rubber roller to form a flame-retardant line 302, the hot pressing temperature is 65°C, and the thickness of the flame-retardant line 302 is the same as that of the metal layer 200
[0079] Example 7 is the seventh embodiment of the present application, which provides a preparation method of a flame-retardant composite current collector, the method comprises:
[0080] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of the polymer film, wherein the polymer film is formed of PET (polyethylene terephthalate), and the metal layer 200 is formed of aluminum.
[0081] A plurality of metal blocks 301 with a thickness of 900 nm are evaporated on the surface of the metal layer 200, and a mesh spacing a with a width of 5 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0082] The MoS2 nanosheet (prepared by liquid phase exfoliation method) is treated with cetyltrimethylammonium bromide to make its surface positively charged, 1.2 mol / L APP (ammonium polyphosphate) is dispersed in water, the pH is adjusted to alkaline, preferably pH = 10, and the surface of APP (ammonium polyphosphate) is negatively charged (-PO4 3- ), the two are mixed and stirred, APP (ammonium polyphosphate) is adsorbed on the surface of MoS2 by electrostatic action to form a core-shell structure, and after centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form a nano flame-retardant powder.
[0083] The surface of the metal block 301 is shielded, and the flame-retardant line 302 powder is sprayed inside the mesh spacing a, and the MoS2 / APP powder is charged by electrostatic spraying and then adsorbed inside the mesh spacing a on the grounded current collector.
[0084] Finally, the nanometer flame-retardant powder inside the net-shaped interval a is pressed by a rubber roller to form the flame-retardant line 302, and the hot-pressing temperature is 65°C, and the thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0085] Embodiment 8, which is an eighth embodiment of the present application, provides a preparation method of a flame-retardant composite current collector, and the method comprises the following steps of:
[0086] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of a polymer film, wherein the polymer film is formed of PET (polyethylene terephthalate), and the metal layer 200 is formed of aluminum.
[0087] A plurality of metal blocks 301 with a thickness of 900 nm are evaporated on the surface of the metal layer 200, and a net-shaped interval a with a width of 50 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0088] MoS2nanosheets (prepared by a liquid-phase exfoliation method) are treated with cetyltrimethylammonium bromide to make the surfaces of the MoS2nanosheets positively charged, 1.2 mol / L APP (ammonium polyphosphate) is dispersed in water, and the pH is adjusted to be alkaline, preferably pH = 10, so that the surfaces of the APP (ammonium polyphosphate) are negatively charged (-PO4 3- ), the two are mixed and stirred, the APP (ammonium polyphosphate) is adsorbed on the surfaces of the MoS2nanosheets by electrostatic action to form a core-shell structure, and after centrifugal washing, the shell layer is dried and solidified by a vacuum oven (oven temperature 100°C) to form nanometer flame-retardant powder.
[0089] The surfaces of the metal blocks 301 are shielded, and the flame-retardant line 302 powder is sprayed inside the net-shaped interval a, and the MoS2 / APP powder is charged by an electrostatic spraying method and then adsorbed inside the net-shaped interval a on the grounded current collector.
[0090] Finally, the nanometer flame-retardant powder inside the net-shaped interval a is pressed by a rubber roller to form the flame-retardant line 302, and the hot-pressing temperature is 65°C, and the thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0091] Embodiment 9: In this embodiment, the MoS2-coated APP (ammonium polyphosphate) is exactly opposite to that in Embodiment 3, and the method comprises the following steps of:
[0092] A metal layer 200 with a thickness of 30-80 nm is evaporated on the surface of a polymer film, wherein the polymer film is formed of PET (polyethylene terephthalate), and the metal layer 200 is formed of aluminum.
[0093] A plurality of metal blocks 301 with a thickness of 900 nm are evaporated on the surface of the metal layer 200, and a net-shaped interval a with a width of 50 μm is formed between the plurality of metal blocks 301, and the metal blocks 301 are made of aluminum.
[0094] Slowly drop the modified APP (ammonium polyphosphate) dispersion into the MoS2 dispersion, stir or ultrasonic assist, rely on electrostatic attraction to make MoS2 adsorbed on the surface of APP (ammonium polyphosphate). After centrifugal washing and drying, APP (ammonium polyphosphate) @ MoS2 core-shell structure is obtained.
[0095] Shield the surface of the metal block 301, and spray the flame-retardant line 302 inside the reticular interval a. After the MoS2 / APP powder is charged by the method of electrostatic spraying, it is adsorbed inside the reticular interval a on the grounded current collector.
[0096] Finally, the nanometer flame-retardant powder inside the reticular interval a is pressed by the rubber roller to form the flame-retardant line 302. The hot-pressing temperature is 65°C, and the thickness of the flame-retardant line 302 is the same as that of the metal layer 200.
[0097] Comparative Example 1, S1: a (30-80nm) thick primer aluminum layer is first evaporated on the surface of the PET polymer film. The aluminum layer is uniformly and densely distributed;
[0098] S2: the metal aluminum layer is obtained by a one-time evaporation device, and the thickness is 900nm;
[0099] S3: the composite aluminum current collector is prepared.
[0100] Comparative Example 2, S1: a (30-80nm) thick primer aluminum layer is first evaporated on the surface of the PET polymer film. The aluminum layer is uniformly and densely distributed;
[0101] S2: a plurality of metal blocks 301 with a thickness of 900nm are evaporated on the surface of the metal layer 200, and a reticular interval a with a width of 40μm is formed between the plurality of metal blocks 301. The metal blocks 301 are made of metal aluminum;
[0102] S3: fill the Exolit AP462 flame retardant inside the reticular interval a;
[0103] S4: the composite aluminum current collector is prepared.
[0104] A 25Ah soft package battery is made by using the above current collector, and the battery formula is as follows:
[0105] Product formula battery performance test scheme:
[0106] 1. Positive electrode ternary system: NCM811: SP: PVDF5130: CNT = 96: 1.8: 1.7: 0.5;
[0107] 2. The positive electrode current collector is the example and the comparative example in the application;
[0108] 3. Negative electrode graphite system: graphite: LA136D: SP: CNT: CMC = 96: 2.3: 0.9: 0.4: 0.4;
[0109] 4. The negative electrode foil is a conventional 6 pm copper foil;
[0110] 5. Electrolyte 1.0 M LiPF6 / EC: EMC (volume ratio 3:7), N / P value = 1.08;
[0111] 6. The battery uses a soft pack small battery, and the design nominal capacity is 25.0 Ah.
[0112] The following data shown in Table 1 were obtained by testing the safety performance of needle puncture:
[0113] Table 1
[0114]
[0115] Through the above needle puncture test, it can be concluded that when the thickness of the metal block and the thickness of the flame-retardant line are 900 nm, the grid interval is 40-50 pm, the concentration of ammonium polyphosphate is 1.2 mol / L, and the hot-pressing temperature is 65°C, the core-shell structure flame-retardant effect of APP coated MoS2 is the best, and the preferred grid interval is 40 pm. At the same time, the grid-shaped flame-retardant line setting has a significant progress compared with the comparative example 1 without the flame-retardant line setting, and the flame-retardant line made of APP and MoS2 has a much better effect than the existing Exolit AP462 flame retardant.
[0116] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.
Claims
1. A flame-retardant composite current collector, characterized in that: include, a polymer film layer (100); a metal layer (200) disposed on the surface of the polymer film layer (100); The flame retardant layer (300) is arranged on the surface of the metal layer (200), and comprises a plurality of metal blocks (301), mesh spacings (a) arranged between the metal blocks (301), and flame retardant lines (302) arranged inside the mesh spacings (a).
2. The flame-retardant composite current collector according to claim 1, characterized in that: The flame retardant wire (302) is made of MoS2 nanowires and ammonium polyphosphate to form a core-shell structure; The core-shell structure of the flame-retardant thread (302) is formed by ammonium polyphosphate adsorbed on the surface of MoS2.
3. The flame-retardant composite current collector according to claim 1, characterized in that: The flame retardant wire (302) is made of MoS2 nanowires and ammonium polyphosphate to form a core-shell structure; The core-shell structure of the flame-retardant thread (302) is formed by MoS2 being adsorbed on the surface of ammonium polyphosphate.
4. The flame-retardant composite current collector according to any one of claims 1 to 3, characterized in that: The metal block (301) is in any of the following shapes: rhombus, circle, square, polygon or ellipse.
5. The flame-retardant composite current collector according to claim 4, characterized in that: The plurality of metal blocks (301) include complete blocks (301a) not connected to the boundary of the metal layer (200), and residual blocks (301b) connected to the boundary of the metal layer (200), wherein the shape of the residual blocks (301b) is obtained by cutting the boundary line of the metal layer (200) in accordance with the shape of the complete blocks (301a); A plurality of complete blocks (301a) of uniform shape and a plurality of residual blocks (301b) are spread over the surface of the metal layer (200) at equal mesh intervals (a).
6. The flame-retardant composite current collector according to any one of claims 1 to 3 and 5, characterized in that: The thickness of the metal layer (200) is 30-80 nm.
7. The flame-retardant composite current collector according to any one of claims 1 to 3 and 5, characterized in that: The thickness of the metal block (301) is 500-1000 nm.
8. The flame-retardant composite current collector according to claim 7, characterized in that: The width of the mesh-like space (a) is 5-50 μm.
9. A method for preparing a flame-retardant composite current collector, characterized in that: include; Vapor depositing a 30-80 nm metal layer (200) on the surface of the polymer film; A plurality of metal blocks (301) with a thickness of 500-1000 nm are evaporated on the surface of the metal layer (200), and a mesh-like gap (a) with a width of 5-50 μm is formed between the plurality of metal blocks (301); MoS2 nanowires and ammonium polyphosphate are made into core-shell nano flame retardant powders; The surface of the metal block (301) is shielded, and the flame retardant wire (302) is powder-sprayed inside the mesh spacer (a); The nano flame retardant powder inside the mesh space (a) is pressed by a rubber roller to form a flame retardant line (302).
10. The method for preparing a flame-retardant composite current collector according to claim 9, wherein: The MoS2 surface was made positively charged by treating MoS2 nanosheets with hexadecyltrimethylammonium bromide; By dispersing 0.8-1.2 mol / L ammonium polyphosphate in water and adjusting the pH to alkaline, the surface of the ammonium polyphosphate is negatively charged; The two are mixed and stirred, and the ammonium polyphosphate is adsorbed on the surface of MoS2 through electrostatic action to form a core-shell structure, or MoS2 is adsorbed on the surface of ammonium polyphosphate to form a core-shell structure; The core-shell structure formed by MoS2 and ammonium polyphosphate is centrifugally washed and then dried and solidified in a vacuum oven to form nano flame retardant powder.