Composite diaphragm and lithium ion battery with same

Abstract

The composite membrane comprises a base membrane layer and a functional layer, the functional layer comprises at least two material layers which are arranged in a stacked mode, and the at least two material layers are selected from an inorganic ceramic layer, a solid electrolyte layer and a high-temperature-resistant polymer layer. The at least two material layers are arranged on at least one side of the base film layer; wherein the functional layer comprises a high-temperature-resistant polymer layer, and the high-temperature-resistant polymer layer is arranged on the surface of the base film layer; when the functional layer does not comprise the high-temperature-resistant polymer layer, the solid electrolyte layer is arranged on the surface of the base film layer. According to the composite diaphragm, the heat resistance of the diaphragm is improved, and the use safety of the lithium battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a composite diaphragm and a lithium ion battery having the same. Background Art

[0002] The separator in a lithium-ion battery isolates electrons from the positive and negative electrodes, preventing short circuits. It also facilitates ion conduction between the positive and negative electrodes during charging and discharging. Due to its poor heat resistance, the separator easily shrinks when heated, compromising the isolation of electrons between the positive and negative electrodes and potentially causing a short circuit.

[0003] Related art coats an inorganic ceramic layer on the surface of a diaphragm to form a composite diaphragm to improve the heat resistance of the diaphragm. However, the heat resistance effect is not ideal. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a composite diaphragm, which improves the heat resistance of the diaphragm and improves the safety of lithium batteries.

[0005] The utility model also aims to provide a lithium ion battery having the composite diaphragm.

[0006] According to the embodiment of the first aspect of the present invention, the composite diaphragm includes a base membrane layer and a functional layer, the functional layer includes at least two material layers stacked together, the at least two material layers are selected from an inorganic ceramic layer, a solid electrolyte layer and a high-temperature resistant polymer layer, and the at least two material layers are arranged on at least one side of the base membrane layer; wherein, when the functional layer includes a high-temperature resistant polymer layer, the high-temperature resistant polymer layer is arranged on the surface of the base membrane layer; when the functional layer does not include a high-temperature resistant polymer layer, the solid electrolyte layer is arranged on the surface of the base membrane layer.

[0007] According to the composite diaphragm of the present invention, by arranging at least two material layers selected from an inorganic ceramic layer, a solid electrolyte layer and a high-temperature resistant polymer layer on at least one side of the base membrane layer, the high-temperature resistance and stability of the composite diaphragm are improved. At the same time, it can play a role of mechanical support for the base membrane layer, making the base membrane layer less likely to shrink, ensuring the integrity of the base membrane layer's morphology, ensuring the isolation of the base membrane layer from the conduction of positive and negative electrons, thereby improving the safety of the battery.

[0008] According to some embodiments of the present invention, functional layers are respectively provided on both sides of the base film layer.

[0009] According to some embodiments of the present invention, at least two material layers are respectively disposed on both sides of the base film layer.

[0010] According to some embodiments of the present invention, the composite diaphragm further comprises a high temperature resistant polymer porous layer, which is arranged on at least one side of the base membrane layer and is located at the outermost layer away from the base membrane layer; the composite diaphragm comprises four layers.

[0011] According to some embodiments of the present invention, the functional layer includes an inorganic ceramic layer, which includes a plurality of inorganic ceramic particles; the high-temperature resistant polymer porous layer has pores, and the inorganic ceramic particles are disposed in the pores.

[0012] According to some embodiments of the present invention, the porosity of the high temperature resistant polymer porous layer is 30%-98%.

[0013] According to some embodiments of the present invention, the high temperature resistant polymer layer is an aramid layer; the thickness of the high temperature resistant polymer layer is 1 μm-5 μm.

[0014] According to some embodiments of the present invention, the inorganic ceramic layer is at least one of a titanium dioxide layer, a silicon dioxide layer, a zirconium dioxide layer, a molybdenum-doped silicon dioxide layer, a boron nitride layer, an aluminum nitride layer, a silicon nitride layer, a titanium nitride layer, a zirconium nitride layer, a magnesium nitride layer, a zirconium boride layer, a silicon boride layer, a vanadium boride layer, a titanium boride layer, and a magnesium boride layer; and the thickness of the inorganic ceramic layer is 1 μm-5 μm.

[0015] According to some embodiments of the present invention, the solid electrolyte layer is at least one of a lithium lanthanum zirconium oxide layer, a lithium lanthanum titanium oxide layer, a tantalum-doped lithium lanthanum zirconium oxide layer, an aluminum-doped lithium lanthanum zirconium oxide layer, a lithium phosphorus-sulfur-chloride layer, a lithium germanium phosphorus-sulfur compound layer, a lithium titanium aluminum phosphate compound layer, and a lithium germanium aluminum phosphate compound layer; the thickness of the solid electrolyte layer is 1 μm-5 μm.

[0016] According to some embodiments of the present invention, the base film layer is a polypropylene layer or a polyethylene layer; the thickness of the base film layer is 5 μm-12 μm.

[0017] According to some embodiments of the present invention, the high-temperature resistant polymer porous layer is one of a polytetrafluoroethylene layer, a polyimide layer, and a thermoplastic polyurethane layer; and the thickness of the high-temperature resistant polymer porous layer is 3 μm-12 μm.

[0018] According to some embodiments of the present invention, the thickness of the composite membrane is 10 μm-30 μm.

[0019] The lithium-ion battery according to the embodiment of the second aspect of the present invention includes the composite separator in the above embodiment.

[0020] According to the lithium-ion battery of the embodiment of the present utility model, the use safety of the lithium-ion battery is improved by adopting the composite diaphragm of the above embodiment.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a schematic structural diagram of a first embodiment of a composite diaphragm according to an embodiment of the present application;

[0023] Figure 2 1 is a schematic structural diagram of a second embodiment of the composite diaphragm according to the embodiment of the present application;

[0024] Figure 3 1 is a schematic structural diagram of a third embodiment of a composite diaphragm according to an embodiment of the present application;

[0025] Figure 4 1 is a schematic structural diagram of a fourth embodiment of a composite diaphragm according to an embodiment of the present application;

[0026] Figure 5 is a schematic structural diagram of a fifth embodiment of the composite diaphragm according to the embodiments of the present application;

[0027] Figure 6 is a schematic structural diagram of a sixth embodiment of the composite diaphragm according to the embodiments of the present application;

[0028] Figure 7 1 is a schematic structural diagram of a seventh embodiment of a composite diaphragm according to an embodiment of the present application;

[0029] Figure 8 is a schematic structural diagram of an eighth embodiment of a composite diaphragm according to an embodiment of the present application;

[0030] Figure 9 is a schematic structural diagram of a ninth embodiment of a composite diaphragm according to an embodiment of the present application;

[0031] Figure 10 is a schematic structural diagram of a tenth embodiment of a composite diaphragm according to an embodiment of the present application;

[0032] Figure 11 is a schematic structural diagram of an eleventh embodiment of a composite diaphragm according to an embodiment of the present application;

[0033] Figure 12 is a schematic structural diagram of a twelfth embodiment of the composite diaphragm according to the embodiments of the present application;

[0034] Figure 13 is a schematic structural diagram of a thirteenth embodiment of a composite diaphragm according to an embodiment of the present application;

[0035] Figure 14is a schematic structural diagram of a fourteenth embodiment of a composite diaphragm according to an embodiment of the present application;

[0036] Figure 15 is a schematic structural diagram of a fifteenth embodiment of the composite diaphragm according to the embodiments of the present application;

[0037] Figure 16 This is a schematic diagram of a first embodiment of a composite diaphragm according to an embodiment of the present application in which a high-temperature resistant polymer porous layer is filled with inorganic ceramic particles;

[0038] Figure 17 2 is a schematic diagram of a second embodiment of a composite diaphragm according to an embodiment of the present application in which a high-temperature resistant polymer porous layer is filled with inorganic ceramic particles;

[0039] Figure 18 This is a schematic structural diagram of a high-temperature resistant polymer porous layer filled with inorganic ceramic particles of a composite diaphragm according to an embodiment of the present application.

[0040] Reference numerals:

[0041] Composite diaphragm 100,

[0042] Base film layer 10,

[0043] High temperature resistant polymer porous layer 20, pores 21,

[0044] Inorganic ceramic layer 30 , solid electrolyte layer 40 , high temperature resistant polymer layer 50 , and inorganic ceramic particles 60 . DETAILED DESCRIPTION

[0045] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0046] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art will appreciate the applicability of other processes and / or the use of other materials.

[0047] The composite separator 100 and a lithium-ion battery having the same according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0048] Reference Figure 1-Figure 4 According to the embodiment of the first aspect of the present invention, the composite diaphragm 100 includes a base membrane layer 10 and a functional layer, the functional layer includes at least two material layers stacked together, at least two material layers are selected from an inorganic ceramic layer 30, a solid electrolyte layer 40 and a high-temperature resistant polymer layer 50, and at least two material layers are arranged on at least one side of the base membrane layer 10; wherein, when the functional layer includes the high-temperature resistant polymer layer 50, the high-temperature resistant polymer layer 50 is arranged on the surface of the base membrane layer 10; when the functional layer does not include the high-temperature resistant polymer layer 50, the solid electrolyte layer 40 is arranged on the surface of the base membrane layer 10.

[0049] Specifically, refer to Figure 1-Figure 4 The composite diaphragm 100 in the embodiment of the present invention includes a base membrane layer 10, which is used to isolate the electronic conduction between the positive and negative electrodes to prevent the battery from short circuiting, and is used for ion conduction between the positive and negative electrodes when the battery is charged and discharged.

[0050] The composite diaphragm 100 further includes a functional layer, which includes at least two material layers stacked together, and the at least two material layers are selected from an inorganic ceramic layer 30, a solid electrolyte layer 40, and a high temperature resistant polymer layer 50. For example, referring to Figure 1-Figure 4 , the functional layer includes an inorganic ceramic layer 30 and a solid electrolyte layer 40. In this case, the composite diaphragm 100 may include a base membrane layer 10, a solid electrolyte layer 40 and an inorganic ceramic layer 30 stacked in sequence; or, the functional layer includes an inorganic ceramic layer 30 and a high-temperature resistant polymer layer 50. In this case, the composite diaphragm 100 may include a base membrane layer 10, a high-temperature resistant polymer layer 50 and an inorganic ceramic layer 30 stacked in sequence; or, the functional layer includes a solid electrolyte layer 40 and a high-temperature resistant polymer layer 50. In this case, the composite diaphragm 100 may include a base membrane layer 10, a high-temperature resistant polymer layer 50 and a solid electrolyte layer 40 stacked in sequence.

[0051] Among them, the inorganic ceramic layer 30 can improve the heat resistance of the composite diaphragm 100. At the same time, the high hardness of the inorganic ceramic layer 30 can provide mechanical support for the base film layer 10, making the base film layer 10 less likely to shrink, ensuring the integrity of the base film layer 10's morphology, and ensuring the isolation of the base film layer 10 from the conduction of positive and negative electrons, thereby improving the safety of the battery. The high temperature resistant polymer layer 50 can further improve the high temperature resistance of the composite diaphragm 100. At the same time, the high temperature resistant polymer layer 50 can improve the compatibility of the interface. Therefore, when the functional layer includes the high temperature resistant polymer layer 50, the high temperature resistant polymer layer 50 is arranged on the surface of the base film layer 10, that is, arranged adjacent to the base film layer 10, which can improve the compatibility of the base film layer 10 with other layers, thereby improving the stability of the composite diaphragm 100. Since the solid electrolyte layer 40 has high ionic conductivity, excellent thermal stability and excellent mechanical properties, when the functional layer does not include the high-temperature resistant polymer layer 50, the solid electrolyte layer 40 is arranged on the surface of the base membrane layer 10, that is, it is arranged close to the base membrane layer 10, which can improve the ionic conductivity and at the same time provide mechanical support for the base membrane layer 10, making the base membrane layer 10 less likely to shrink, thereby ensuring the integrity of the base membrane layer 10's morphology and improving the safety of the battery.

[0052] It can be understood that at least two material layers can be provided with two layers respectively, and are respectively provided on both sides of the base film layer 10, or can be provided with one layer and two layers respectively, and one of the two layers is respectively provided on both sides of the base film layer 10. The functional layer can also include an inorganic ceramic layer 30, a solid electrolyte layer 40 and a high temperature resistant polymer layer 50. At this time, the composite diaphragm 100 may include a base film layer 10, a high temperature resistant polymer layer 50, an inorganic ceramic layer 30 and a solid electrolyte layer 40 stacked in sequence; or, a base film layer 10, a high temperature resistant polymer layer 50, a solid electrolyte layer 40 and an inorganic ceramic layer 30; or, a high temperature resistant polymer layer 50, a base film layer 10, a high temperature resistant polymer layer 50, an inorganic ceramic layer 30 and a solid electrolyte layer 40; or, a high temperature resistant polymer layer 50, a base film layer 10, a high temperature resistant polymer layer 50, a solid electrolyte layer 40 and an inorganic ceramic layer 30; or, electrolyte layer 40 and inorganic ceramic layer 30; or, inorganic ceramic layer 30, high temperature resistant polymer layer 50, base membrane layer 10, high temperature resistant polymer layer 50, inorganic ceramic layer 30 and solid electrolyte layer 40; or, solid electrolyte layer 40, inorganic ceramic layer 30, high temperature resistant polymer layer 50, base membrane layer 10, high temperature resistant polymer layer 50, inorganic ceramic layer 30 and solid electrolyte layer 40; or, solid electrolyte layer 40, inorganic ceramic layer 30, high temperature resistant polymer layer 50, base membrane layer 10, high temperature resistant polymer layer 50, solid electrolyte layer 40 and inorganic ceramic layer 30; or, inorganic ceramic layer 30, solid electrolyte layer 40, high temperature resistant polymer layer 50, base membrane layer 10, high temperature resistant polymer layer 50, solid electrolyte layer 40 and inorganic ceramic layer 30.

[0053] Therefore, refer to Figure 1-Figure 4 According to the composite diaphragm 100 of the present invention, by arranging at least two material layers selected from the inorganic ceramic layer 30, the solid electrolyte layer 40 and the high-temperature resistant polymer layer 50 on at least one side of the base membrane layer 10, the high-temperature resistance and stability of the composite diaphragm 100 are improved. At the same time, it can play a role in mechanical support for the base membrane layer 10, making the base membrane layer 10 not easy to shrink, ensuring the integrity of the morphology of the base membrane layer 10, and ensuring the isolation of the base membrane layer 10 from the conduction of positive and negative electrons, thereby improving the safety of the battery.

[0054] In some embodiments of the present invention, referring to Figure 5-Figure 8 , functional layers are provided on both sides of the base film layer 10.

[0055] Specifically, refer to Figure 5-Figure 8, a high-temperature resistant polymer layer 50 and an inorganic ceramic layer 30 can be respectively provided on both sides of the base film layer 10. In this case, the composite diaphragm 100 may include an inorganic ceramic layer 30, a high-temperature resistant polymer layer 50, a base film layer 10, a high-temperature resistant polymer layer 50 and an inorganic ceramic layer 30 stacked in sequence; or, a high-temperature resistant polymer layer 50 and a solid electrolyte layer 40 can be respectively provided on both sides of the base film layer 10. In this case, the composite diaphragm 100 may include a solid electrolyte layer 40, a high-temperature resistant polymer layer 50, a base film layer 10, a high-temperature resistant polymer layer 50 and a solid electrolyte layer 40 stacked in sequence; or, an inorganic ceramic layer 30 and a solid electrolyte layer 40 can be respectively provided on both sides of the base film layer 10. In this case, the composite diaphragm 100 may include a solid electrolyte layer 40, a high-temperature resistant polymer layer 50, a base film layer 10, a high-temperature resistant polymer layer 50 and a solid electrolyte layer 40 stacked in sequence. The inorganic ceramic layer 30, the solid electrolyte layer 40, the base membrane layer 10, the solid electrolyte layer 40 and the inorganic ceramic layer 30 are stacked; or, the high temperature resistant polymer layer 50, the solid electrolyte layer 40 and the inorganic ceramic layer 30 can be respectively set on both sides of the base membrane layer 10. At this time, the composite diaphragm 100 may include the inorganic ceramic layer 30, the solid electrolyte layer 40, the high temperature resistant polymer layer 50, the base membrane layer 10, the high temperature resistant polymer layer 50, the solid electrolyte layer 40 and the inorganic ceramic layer 30 stacked in sequence, or the composite diaphragm 100 may include the solid electrolyte layer 40, the inorganic ceramic layer 30, the high temperature resistant polymer layer 50, the base membrane layer 10, the high temperature resistant polymer layer 50, the inorganic ceramic layer 30 and the solid electrolyte layer 40 stacked in sequence.

[0056] By arranging functional layers on both sides of the base membrane layer 10, the high temperature resistance and stability of both sides of the base membrane layer 10 are improved. At the same time, it can provide mechanical support to both sides of the base membrane layer 10, so that the base membrane layer 10 is not easy to shrink on both sides, thereby ensuring the integrity of the shape of the base membrane layer 10 and ensuring the isolation of the base membrane layer 10 from the conduction of positive and negative electrons, thereby improving the safety of the battery.

[0057] In some embodiments of the present invention, referring to Figures 9-12 At least two material layers are respectively arranged on both sides of the base film layer 10.

[0058] Specifically, refer to Figures 9-12, the high temperature resistant polymer layer 50 and the inorganic ceramic layer 30 are respectively arranged on both sides of the base membrane layer 10. At this time, the composite diaphragm 100 may include the high temperature resistant polymer layer 50, the base membrane layer 10, and the inorganic ceramic layer 30 stacked in sequence, or the high temperature resistant polymer layer 50, the base membrane layer 10, the high temperature polymer layer 50, and the inorganic ceramic layer 30 stacked in sequence, or the inorganic ceramic layer 30, the base membrane layer 10, the high temperature polymer layer 50, and the inorganic ceramic layer 30 stacked in sequence; or the inorganic ceramic layer 30 and the solid electrolyte layer 40 are respectively arranged on both sides of the base membrane layer 10. At this time, the composite diaphragm 100 may include the solid electrolyte layer 40, the base membrane layer 10, and the inorganic ceramic layer 30 stacked in sequence, or the solid electrolyte layer 40, the base membrane layer 10, the solid electrolyte layer 40, and the inorganic ceramic layer 30 stacked in sequence; or the high temperature resistant polymer layer 50, the base membrane layer 10, the high temperature polymer layer 50, and the inorganic ceramic layer 30 stacked in sequence The polymer layer 50 and the solid electrolyte layer 40 are respectively arranged on both sides of the base membrane layer 10. At this time, the composite diaphragm 100 may include a solid electrolyte layer 40, a base membrane layer 10, and a high-temperature polymer layer 50 stacked in sequence, or a solid electrolyte layer 40, a base membrane layer 10, a solid electrolyte layer 40, and a high-temperature polymer layer 50 stacked in sequence, or a high-temperature polymer layer 50, a base membrane layer 10, a high-temperature polymer layer 50, and a solid electrolyte layer 40 stacked in sequence; or a high-temperature resistant polymer layer 50, an inorganic ceramic layer 30 and a solid electrolyte layer 40 are respectively arranged on both sides of the base membrane layer 10. At this time, the composite diaphragm 100 may include an inorganic ceramic layer 30, a high-temperature resistant polymer layer 50, a base membrane layer 10 and a solid electrolyte layer 40 stacked in sequence, or a solid electrolyte layer 40, a high-temperature resistant polymer layer 50, a base membrane layer 10 and an inorganic ceramic layer 30, or a high-temperature resistant polymer layer 50, a base membrane layer 10, a solid electrolyte layer 40 and an inorganic ceramic layer 30.

[0059] Alternatively, a high temperature resistant polymer layer 50 and a solid electrolyte layer 40, as well as a high temperature resistant polymer layer 50 and an inorganic ceramic layer 30 can be respectively provided on both sides of the base film layer 10. In this case, the composite diaphragm 100 may include a solid electrolyte layer 40, a high temperature resistant polymer layer 50, a base film layer 10, a high temperature resistant polymer layer 50 and an inorganic ceramic layer 30 stacked in sequence; Alternatively, a high temperature resistant polymer layer 50 and a solid electrolyte layer 40, as well as a solid electrolyte layer 40 and an inorganic ceramic layer 30 can be respectively provided on both sides of the base film layer 10. In this case, The composite diaphragm 100 may include a solid electrolyte layer 40, a high temperature resistant polymer layer 50, a base membrane layer 10, a solid electrolyte layer 40, and an inorganic ceramic layer 30 stacked in sequence; or, a high temperature resistant polymer layer 50 and an inorganic ceramic layer 30, as well as a solid electrolyte layer 40 and an inorganic ceramic layer 30, may be disposed on both sides of the base membrane layer 10. In this case, the composite diaphragm 100 may include an inorganic ceramic layer 30, a high temperature resistant polymer layer 50, a base membrane layer 10, a solid electrolyte layer 40, and an inorganic ceramic layer 30 stacked in sequence. By arranging at least two material layers on both sides of the base membrane layer 10, the high temperature resistance and stability of both sides of the base membrane layer 10 are improved. At the same time, the base membrane layer 10 can be mechanically supported on both sides, making it difficult for the base membrane layer 10 to shrink on both sides, thereby ensuring the integrity of the base membrane layer 10 and the isolation of the base membrane layer 10 from the conduction of positive and negative electrons, thereby improving the safety of the battery.

[0060] In some embodiments of the present invention, referring to Figure 13-15 The composite membrane 100 further includes a high temperature resistant polymer porous layer 20, which is disposed on at least one side of the base membrane layer 10 and is located at the outermost layer away from the base membrane layer 10; the composite membrane 100 includes four layers.

[0061] Specifically, refer to Figure 13-15 The composite membrane 100 may include a base membrane layer 10, an inorganic ceramic layer 30, a solid electrolyte layer 40 and a high-temperature resistant polymer porous layer 20. At this time, the composite membrane 100 may include a base membrane layer 10, a solid electrolyte layer 40, an inorganic ceramic layer 30 and a high-temperature resistant polymer porous layer 20 stacked in sequence; or, a solid electrolyte layer 40, a base membrane layer 10, an inorganic ceramic layer 30 and a high-temperature resistant polymer porous layer 20; or, an inorganic ceramic layer 30, a base membrane layer 10, a solid electrolyte layer 40 and a high-temperature resistant polymer porous layer 20.

[0062] The composite membrane 100 may also include a base membrane layer 10, an inorganic ceramic layer 30, a high temperature resistant polymer layer 50 and a high temperature resistant polymer porous layer 20. At this time, the composite membrane 100 may include a base membrane layer 10, a high temperature resistant polymer layer 50, an inorganic ceramic layer 30 and a high temperature resistant polymer porous layer 20 stacked in sequence; or, a high temperature resistant polymer layer 50, a base membrane layer 10, an inorganic ceramic layer 30 and a high temperature resistant polymer porous layer 20; or, an inorganic ceramic layer 30, a base membrane layer 10, a high temperature resistant polymer layer 50 and a high temperature resistant polymer porous layer 20.

[0063] The composite diaphragm 100 may also include a base membrane layer 10, a solid electrolyte layer 40, a high temperature resistant polymer layer 50 and a high temperature resistant polymer porous layer 20. At this time, the composite diaphragm 100 may include a base membrane layer 10, a high temperature resistant polymer layer 50, a solid electrolyte layer 40 and a high temperature resistant polymer porous layer 20 stacked in sequence; or, a high temperature resistant polymer layer 50, a base membrane layer 10, a solid electrolyte layer 40 and a high temperature resistant polymer porous layer 20; or, a solid electrolyte layer 40, a base membrane layer 10, a high temperature resistant polymer layer 50 and a high temperature resistant polymer porous layer 20.

[0064] The high-temperature resistant polymer porous layer 20 has good high-temperature resistance, which makes the base membrane layer 10 less likely to shrink due to heat, thereby ensuring that the base membrane layer 10 isolates the electron conduction between the positive and negative electrodes, improving the safety of the battery. At the same time, the porous structure is conducive to the ion conduction between the positive and negative electrodes when the battery is charged and discharged.

[0065] In some embodiments of the present invention, referring to Figure 16-18 The functional layer includes an inorganic ceramic layer 30 , and the inorganic ceramic layer 30 includes a plurality of inorganic ceramic particles 60 ; the high temperature resistant polymer porous layer 20 has pores 21 , and the inorganic ceramic particles 60 are disposed in the pores 21 .

[0066] By filling the pores 21 of the high-temperature resistant polymer porous layer 20 with inorganic ceramic particles 60, the mechanical support of the high-temperature resistant polymer porous layer 20 is improved, making the base membrane layer 10 less likely to shrink. At the same time, filling the inorganic ceramic particles 60 into the pores 21 of the high-temperature resistant polymer porous layer 20 improves adhesion, reduces the thickness of the composite diaphragm 100, and enhances the wettability of the electrolyte.

[0067] Specifically, refer to Figure 16-18 The composite membrane 100 may include a base membrane layer 10, a solid electrolyte layer 40 / high temperature resistant polymer layer 50, an inorganic ceramic layer 30, and a high temperature resistant polymer porous layer 20 filled with inorganic ceramic particles 60. For example, referring to Figure 16The composite diaphragm 100 includes a high temperature resistant polymer porous layer 20 filled with inorganic ceramic particles 60, an inorganic ceramic layer 30, a base membrane layer 10 and a solid electrolyte layer 40 / high temperature resistant polymer layer 50, which are stacked in sequence; or, referring to Figure 17 The composite diaphragm 100 includes a high-temperature resistant polymer porous layer 20 filled with inorganic ceramic particles 60, an inorganic ceramic layer 30, a solid electrolyte layer 40 / high-temperature resistant polymer layer 50 and a base membrane layer 10, which are arranged in sequence.

[0068] In some embodiments of the present invention, the porosity 21 of the high temperature resistant polymer porous layer 20 is 30%-98%.

[0069] Specifically, the porosity 21 of the high temperature resistant polymer porous layer 20 can be 30%, 40%, 50%, 57%, 63%, 75%, 86%, 90%, 93%, 98%, etc.

[0070] In some embodiments of the present invention, the high temperature resistant polymer layer 50 is an aramid layer; the thickness of the high temperature resistant polymer layer 50 is 1 μm-5 μm.

[0071] Aramid is selected as the material for the high-temperature-resistant polymer layer 50 due to its excellent properties, including ultra-high strength, high modulus, high-temperature resistance, acid and alkali resistance, light weight, insulation, aging resistance, and long life cycle. The thickness of the high-temperature-resistant polymer layer 50 can be 1 μm, 2 μm, 2.3 μm, 2.7 μm, 3.1 μm, 3.5 μm, 4 μm, 4.7 μm, 5 μm, etc.

[0072] In some embodiments of the present invention, the inorganic ceramic layer 30 is at least one of a titanium dioxide layer, a silicon dioxide layer, a zirconium dioxide layer, a molybdenum-doped silicon dioxide layer, a boron nitride layer, an aluminum nitride layer, a silicon nitride layer, a titanium nitride layer, a zirconium nitride layer, a magnesium nitride layer, a zirconium boride layer, a silicon boride layer, a vanadium boride layer, a titanium boride layer, and a magnesium boride layer; the thickness of the inorganic ceramic layer 30 is 1 μm-5 μm.

[0073] Specifically, the material of the inorganic ceramic layer 30 can be at least one of titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, boron nitride, aluminum nitride, silicon nitride, titanium nitride, zirconium nitride, magnesium nitride, zirconium boride, silicon boride, vanadium boride, titanium boride, and magnesium boride. For example, the inorganic ceramic layer 30 can be one, two, three, or five of the above materials. The thickness of the inorganic ceramic layer 30 can be 1 μm, 2 μm, 2.3 μm, 2.7 μm, 3.1 μm, 3.5 μm, 4 μm, 4.7 μm, 5 μm, etc. Preferably, the thickness of the inorganic ceramic layer 30 can be 1 μm-2 μm. For example, the thickness of the inorganic ceramic layer 30 can be 1 μm, 1.2 μm, 1.4 μm, 1.7 μm, 2 μm, etc.

[0074] In some embodiments of the present invention, the solid electrolyte layer 40 is at least one of a lithium lanthanum zirconium oxide layer, a lithium lanthanum titanium oxide layer, a tantalum-doped lithium lanthanum zirconium oxide layer, an aluminum-doped lithium lanthanum zirconium oxide layer, a lithium phosphorus sulfur chlorine compound layer, a lithium germanium phosphorus sulfur compound layer, a lithium titanium aluminum phosphate compound layer, and a lithium germanium aluminum phosphate compound layer; the thickness of the solid electrolyte layer 40 is 1 μm-5 μm.

[0075] Specifically, the material of the solid electrolyte layer 40 can be at least one of lithium lanthanum zirconium oxide LLZO, lithium lanthanum titanate LLTO, tantalum-doped lithium lanthanum zirconium oxide LLZTO, aluminum-doped lithium lanthanum zirconium oxide LLZAO, lithium phosphorus sulfur chloride LPSCl, lithium germanium phosphorus sulfur LGPS, lithium aluminum titanium phosphate LATP, and lithium aluminum germanium phosphate LAGP. For example, the material can be one, two, three, or five of the above materials. The thickness of the solid electrolyte layer 40 can be 1 μm, 2 μm, 2.3 μm, 2.7 μm, 3.1 μm, 3.5 μm, 4 μm, 4.7 μm, 5 μm, etc. Preferably, the thickness of the solid electrolyte layer 40 can be 1 μm-2 μm. For example, the thickness of the solid electrolyte layer 40 can be 1 μm, 1.2 μm, 1.4 μm, 1.7 μm, 2 μm, etc.

[0076] In some embodiments of the present invention, the base film layer 10 is a polypropylene layer or a polyethylene layer; the thickness of the base film layer 10 is 5 μm-12 μm.

[0077] When the temperature of the battery core is too high, the polypropylene layer or the polyethylene layer will melt and close the pores first, and the high-temperature resistant polymer porous layer 20, the inorganic ceramic layer 30, the solid electrolyte layer 40 and the high-temperature resistant polymer layer 50 will work together to provide mechanical support and high-temperature resistance, improve the overall thermal shrinkage of the composite diaphragm 100, greatly improve the heat resistance stability of the composite diaphragm 100, and reduce the risk of thermal runaway.

[0078] Specifically, the material of the base film layer 10 may be polypropylene (PP) or polyethylene (PE), etc. The thickness of the base film layer 10 may be 5 μm, 6 μm, 8 μm, 11 μm, 12 μm, etc.

[0079] In some embodiments of the present invention, the high temperature resistant polymer porous layer 20 is one of a polytetrafluoroethylene layer, a polyimide layer, and a thermoplastic polyurethane layer; and the thickness of the high temperature resistant polymer porous layer 20 is 3 μm-12 μm.

[0080] Specifically, the material of the high temperature resistant polymer porous layer 20 can be polytetrafluoroethylene (PTFE), polyimide (PI), thermoplastic polyurethane (TPU), and the thickness of the high temperature resistant polymer porous layer 20 can be 3 μm, 4 μm, 6 μm, 8 μm, 11 μm, 12 μm, etc.

[0081] In some embodiments of the present invention, the thickness of the composite membrane 100 is 10 μm-30 μm.

[0082] Specifically, the thickness of the composite separator 100 may be 10 μm, 12 μm, 14 μm, 17 μm, 22 μm, 25 μm, 27 μm, 28 μm, 30 μm, etc.

[0083] The lithium-ion battery according to the embodiment of the second aspect of the present invention includes the composite separator 100 in the above embodiment.

[0084] The lithium-ion battery according to the embodiment of the present invention improves the safety of the lithium-ion battery by adopting the composite separator 100 in the above embodiment.

[0085] Specifically, the lithium-ion battery further includes a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are respectively arranged on both sides of the composite separator 100 .

[0086] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0087] In this utility model, unless otherwise expressly specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0088] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0090] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A composite diaphragm, characterized in that: include: basement membrane layer (10); a functional layer, the functional layer comprising at least two material layers stacked together, the at least two material layers being selected from an inorganic ceramic layer (30), a solid electrolyte layer (40) and a high-temperature resistant polymer layer (50), the at least two material layers being arranged on at least one side of the base film layer (10); Wherein, when the functional layer includes the high-temperature resistant polymer layer (50), the high-temperature resistant polymer layer (50) is provided on the surface of the base film layer (10); When the at least two materials do not include the high-temperature resistant polymer layer (50), the solid electrolyte layer (40) is provided on the surface of the base film layer (10).

2. The composite diaphragm according to claim 1, characterized in that The functional layers are respectively provided on both sides of the base film layer (10).

3. The composite diaphragm according to claim 1, characterized in that The at least two material layers are respectively arranged on both sides of the base film layer (10).

4. The composite diaphragm according to claim 1, characterized in that It also includes a high-temperature resistant polymer porous layer (20), wherein the high-temperature resistant polymer porous layer (20) is provided on at least one side of the base film layer (10) and is located at the outermost layer away from the base film layer (10); The composite diaphragm (100) comprises four layers.

5. The composite diaphragm according to claim 4, characterized in that The functional layer includes the inorganic ceramic layer (30), and the inorganic ceramic layer (30) includes a plurality of inorganic ceramic particles (60); The high-temperature resistant polymer porous layer (20) has pores (21), and the inorganic ceramic particles (60) are arranged in the pores (21).

6. The composite diaphragm according to claim 5, characterized in that The porosity (21) of the high temperature resistant polymer porous layer (20) is 30%-98%.

7. The composite diaphragm according to any one of claims 1 to 6, characterized in that: The high temperature resistant polymer layer (50) is an aramid layer; The thickness of the high temperature resistant polymer layer (50) is 1 μm-5 μm.

8. The composite diaphragm according to any one of claims 1 to 4, characterized in that: The inorganic ceramic layer (30) is at least one of a titanium dioxide layer, a silicon dioxide layer, a zirconium dioxide layer, a molybdenum-doped silicon dioxide layer, a boron nitride layer, an aluminum nitride layer, a silicon nitride layer, a titanium nitride layer, a zirconium nitride layer, a magnesium nitride layer, a zirconium boride layer, a silicon boride layer, a vanadium boride layer, a titanium boride layer, and a magnesium boride layer; The thickness of the inorganic ceramic layer (30) is 1 μm-5 μm.

9. The composite diaphragm according to any one of claims 1 to 6, characterized in that: The solid electrolyte layer (40) is at least one of a lithium lanthanum zirconium oxide layer, a lithium lanthanum titanium oxide layer, a tantalum-doped lithium lanthanum zirconium oxide layer, an aluminum-doped lithium lanthanum zirconium oxide layer, a lithium phosphorus sulfur chlorine compound layer, a lithium germanium phosphorus sulfur compound layer, a lithium titanium aluminum phosphate compound layer, and a lithium germanium aluminum phosphate compound layer; The thickness of the solid electrolyte layer (40) is 1 μm-5 μm.

10. The composite diaphragm according to any one of claims 1 to 6, characterized in that: The base film layer (10) is a polypropylene layer or a polyethylene layer; The thickness of the base film layer (10) is 5 μm-12 μm.

11. The composite diaphragm according to any one of claims 4 to 6, characterized in that: The high temperature resistant polymer porous layer (20) is one of a polytetrafluoroethylene layer, a polyimide layer, and a thermoplastic polyurethane layer; The thickness of the high temperature resistant polymer porous layer (20) is 3 μm-12 μm.

12. The composite diaphragm according to any one of claims 1 to 6, characterized in that: The composite diaphragm (100) has a thickness of 10 μm-30 μm.

13. A lithium ion battery, characterized in that: The composite diaphragm (100) comprises the composite diaphragm (100) according to any one of claims 1 to 12.

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