A lithium ion battery separator prepared using inorganic-organic composite material

Abstract

The utility model discloses a kind of lithium ion battery separators prepared using inorganic organic composite material, specifically related to lithium ion battery field, including battery and the protective film of surface setting thereof, battery inside is provided with positive pole, separator and negative pole, and positive pole, separator and negative pole are sequentially arranged from inside to outside, the surface of the separator is provided with porous substrate, and the inside of porous substrate is provided with first coating, second coating and ceramic coating, the utility model is fused below 130 DEG C due to temperature-sensitive polymer microsphere, the air permeability value is promoted to 3500s / 100ml above from 150-300s / 100ml, can quickly block ion transmission path, simultaneously, by nano fiber network and ceramic particle form three-dimensional skeleton, after 1 hour is baked at 180 DEG C, MD direction shrinkage rate≤5%, again using substrate and coating between setting polydopamine coating layer, to enhance interface bonding force, puncture strength>3000g, greatly improve the puncture strength of battery separator.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, and more specifically, to a lithium-ion battery separator made using inorganic-organic composite materials. Background Technology

[0002] As a core component of rechargeable batteries, the performance of the battery separator directly affects the battery's capacity, cycle life, safety, and rate performance. Traditional polyolefin separators have problems such as insufficient heat resistance (heat shrinkage rate > 10%), low ionic conductivity (< 1 mS / cm), and easy melting and short circuit at high temperatures.

[0003] A search revealed that Chinese Patent Application No. CN201320860921.6 discloses a battery separator, which has a reinforcing layer on each side of two polypropylene layers. For example, the reinforcing layer can be made of polyethylene material and integrally formed with the corresponding polypropylene layer. In this way, the strength of the battery separator is further improved by the reinforcing layer. At the same time, the addition of a polyoxyethylene hydrophilic layer also improves the hydrophilicity of this invention.

[0004] Regarding the above-mentioned technology, the inventors believe that the device has improved some performance through the modification of the reinforcing layer and the polyoxyethylene hydrophilic layer, but there are still defects such as poor coating uniformity, excessively high closed-cell temperature (>150℃) or insufficient mechanical strength.

[0005] Therefore, a lithium-ion battery separator prepared using inorganic-organic composite materials is proposed to address the above problems. Utility Model Content

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a lithium-ion battery separator made of inorganic-organic composite materials to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a lithium-ion battery separator prepared using inorganic-organic composite materials, comprising a battery and a protective film disposed on its surface, characterized in that the battery is provided with a positive electrode, a separator and a negative electrode, and the positive electrode, the separator and the negative electrode are arranged sequentially from the inside to the outside, the surface of the separator is provided with a porous substrate, and the porous substrate is provided with a first coating, a second coating and a ceramic coating.

[0008] Preferably, the porous substrate is composed of polyolefin, aliphatic polyamide and aromatic polyamide, with a thickness of 10-20 μm and a porosity of 30-50%.

[0009] Preferably, the first coating is composed of nanofibers and ceramic particles, the binder is polyvinylidene fluoride, and the dispersant is sodium polyacrylate.

[0010] Preferably, the second coating is a temperature-sensitive polymer microsphere, which is polyethylene glycol diacrylate with a melting temperature of 120-135°C.

[0011] Preferably, the ceramic coating is composed of alumina, boehmite, and boron nitride, wherein it is doped with 0.1-5 wt% lithium bis(fluorosulfonyl)imide and 1-10 wt% vinylene carbonate.

[0012] The technical effects and advantages of this utility model are as follows:

[0013] Compared with existing technologies, this invention, due to the melting of temperature-sensitive polymer microspheres below 130℃, increases the air permeability from 150-300s / 100ml to over 3500s / 100ml, enabling rapid blocking of ion transport pathways. Simultaneously, the nanofiber network and ceramic particles form a three-dimensional skeleton, resulting in a shrinkage rate of ≤5% in the MD direction after baking at 180℃ for 1 hour. Furthermore, a polydopamine coating layer is placed between the substrate and the coating to enhance interfacial adhesion, resulting in a puncture strength >3000g, significantly improving the puncture strength of the battery separator. In summary, the battery separator prepared by this invention reduces the pore-closing temperature and efficiency of the separator while increasing its mechanical strength. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0015] Figure 2 This is a structural schematic diagram of the battery of this utility model.

[0016] Figure 3 This is a structural schematic diagram of the diaphragm of this utility model.

[0017] The attached figures are labeled as follows: 1. Battery; 2. Protective film; 3. Positive electrode; 4. Separator; 5. Negative electrode; 6. Porous substrate; 7. First coating; 8. Second coating; 9. Ceramic coating. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Example 1

[0020] As attached Figures 1 to 3The lithium-ion battery separator shown is made using inorganic-organic composite materials. It includes a battery and a protective film disposed on its surface. The battery contains a positive electrode, a separator, and a negative electrode, which are arranged sequentially from the inside to the outside. The surface of the separator is provided with a porous substrate, and the porous substrate contains a first coating, a second coating, and a ceramic coating.

[0021] Specifically, because the temperature-sensitive polymer microspheres melt below 130℃, the air permeability increases from 150-300s / 100ml to over 3500s / 100ml, which can quickly block ion transport paths. At the same time, a three-dimensional skeleton is formed by the nanofiber network and ceramic particles, and the shrinkage rate in the MD direction is ≤5% after baking at 180℃ for 1 hour. Furthermore, a polydopamine coating layer is set between the substrate and the coating to enhance the interfacial bonding force, resulting in a puncture strength >3000g, which greatly improves the puncture strength of the battery separator. In summary, the battery separator prepared by this invention reduces the pore-closing temperature and efficiency of the separator and increases the mechanical strength of the separator.

[0022] Example 2

[0023] Based on Embodiment 1, the solution in Embodiment 1 will be further described in detail below, with reference to the specific working method described in detail:

[0024] like Figures 1 to 3 As shown, in a preferred embodiment, the porous substrate is composed of polyolefin, aliphatic polyamide and aromatic polyamide, with a thickness of 10-20 μm and a porosity of 30-50%.

[0025] like Figures 1 to 3 As shown, in a preferred embodiment, the first coating is composed of nanofibers and ceramic particles, the binder is polyvinylidene fluoride, and the dispersant is sodium polyacrylate.

[0026] like Figures 1 to 3 As shown, in a preferred embodiment, the second coating is a temperature-sensitive polymer microsphere, which is polyethylene glycol diacrylate with a melting temperature of 120-135°C.

[0027] like Figures 1 to 3 As shown, in a preferred embodiment, the ceramic coating is composed of alumina, boehmite, and boron nitride, wherein it is doped with 0.1-5 wt% lithium bis(fluorosulfonyl)imide and 1-10 wt% vinylene carbonate.

[0028] The working process of this utility model is as follows:

[0029] When this invention is used, the temperature-sensitive polymer microspheres melt below 130℃, increasing the air permeability from 150-300s / 100ml to over 3500s / 100ml, which can quickly block ion transport paths. At the same time, a three-dimensional skeleton is formed by the nanofiber network and ceramic particles, and the shrinkage rate in the MD direction is ≤5% after baking at 180℃ for 1 hour. Furthermore, a polydopamine coating layer is set between the substrate and the coating to enhance the interfacial bonding force, resulting in a puncture strength >3000g, which greatly improves the puncture strength of the battery separator. In summary, the battery separator prepared by this invention reduces the pore-closing temperature and efficiency of the separator and increases the mechanical strength of the separator.

[0030] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0031] Secondly: The accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0032] Finally: The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A lithium-ion battery separator prepared using inorganic-organic composite materials, comprising a battery and a protective film disposed on its surface, characterized in that, The battery has a positive electrode, a separator, and a negative electrode arranged in sequence from the inside to the outside. The surface of the separator is provided with a porous substrate, and the porous substrate is provided with a first coating, a second coating, and a ceramic coating.

2. The lithium-ion battery separator prepared using inorganic-organic composite materials according to claim 1, characterized in that: The porous substrate is composed of polyolefin, aliphatic polyamide and aromatic polyamide, with a thickness of 10-20 μm and a porosity of 30-50%.

3. A lithium-ion battery separator prepared using inorganic-organic composite materials according to claim 1, characterized in that: The first coating is composed of nanofibers and ceramic particles, with polyvinylidene fluoride as the binder and sodium polyacrylate as the dispersant.

4. A lithium-ion battery separator prepared using inorganic-organic composite materials according to claim 1, characterized in that: The second coating is a temperature-sensitive polymer microsphere, which is polyethylene glycol diacrylate with a melting temperature of 120-135℃.

5. A lithium-ion battery separator prepared using inorganic-organic composite materials according to claim 1, characterized in that: The ceramic coating is composed of alumina, boehmite, and boron nitride, wherein it is doped with 0.1-5 wt% lithium bis(fluorosulfonyl)imide and 1-10 wt% vinylene carbonate.

Images