Isolating membrane, naked battery cell, battery cell, battery and electronic equipment

Abstract

The invention provides an isolating membrane, a naked battery cell, a battery cell, a battery and electronic equipment, and the isolating membrane comprises a base membrane which is formed into a sheet structure comprising two surfaces; a first modified electrode coating is arranged on the surface of at least one side of the base membrane, and the first modified electrode comprises nanoscale lithium halide and an active substance; wherein the active substance comprises at least one of lithium titanate and carbon-coated lithium titanate. According to the embodiment of the invention, the isolating membrane has stable chemical stability and relatively high thermal stability, can effectively reduce the expansion of the silicon negative electrode, and avoids gas production.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to isolation membranes, bare cells, batteries and electronic equipment. Background Art

[0002] Lithium-ion batteries are increasingly used in the market. For example, they are used in electronic devices such as mobile phones, notebooks, and tablets. Therefore, the demand for the energy density of lithium-ion batteries is also increasing. At present, the more effective way to improve the energy density of batteries is to use high-energy density materials, for example, using silicon negative electrode materials to make silicon negative electrodes. In the first charge and discharge process of lithium-ion batteries with silicon negative electrodes, the silicon negative electrode reacts with the electrolyte at the solid-liquid interface to form a passivation layer covering the surface of the silicon negative electrode. This passivation layer is also called a solid electrolyte interface film (SolidelEctrolyte Interphase, SEI). The SEI film can not only reduce the charge and discharge efficiency of the silicon negative electrode, but also avoid the damage to the silicon negative electrode caused by the solvent molecules in the electrolyte being co-embedded in the silicon negative electrode. Therefore, the presence of the SEI film can greatly improve the cycle performance and service life of the electrode.

[0003] However, during the charge and discharge process of lithium-ion batteries containing silicon negative electrode materials at a relatively low potential (for example, below 3.0V), during the lithiation process of the silicon negative electrode, lithium ions first form LixSi substances on the surface of the silicon negative electrode material, causing the volume of the silicon negative electrode to expand too much. When the volume of the silicon negative electrode material expands, the SEI will rupture and expose the unpassivated surface, resulting in the continuous reaction of the electrolyte on the surface of the silicon negative electrode material during the cycle, repairing the SEI film again. This continuous reaction not only repairs the SEI film, but also has some side reactions that may produce gas. This will form a vicious cycle, that is, in the process of continuous destruction and repair of the SEI, the battery capacity continues to lose and the cycle expansion increases, reducing the volume energy density of the lithium-ion battery. Therefore, the excessive cycle expansion of the silicon negative electrode has become a major obstacle to improving the volume energy density of lithium-ion batteries. Summary of the invention

[0004] In view of this, the present application provides a separator, a bare cell, a cell, a battery and an electronic device to reduce the problem of expansion of the silicon negative electrode of the battery.

[0005] Some embodiments of the present application provide an isolation membrane. The present application is introduced from multiple aspects below, and the embodiments and beneficial effects of the following multiple aspects can be referenced to each other.

[0006] In a first aspect, the present application provides an isolation membrane, comprising: a base membrane, the base membrane is formed into a sheet structure including two surfaces; a first modified electrode coating is provided on the surface of at least one side of the base membrane, the first modified electrode includes nanoscale lithium halide, and an active substance; wherein the active substance includes lithium titanate and / or carbon-coated lithium titanate.

[0007] According to the isolation film of the embodiment of the present application, the physical contact between the modified electrode and the surface of the silicon negative electrode is equivalent to providing a protective film for the SEI film, which can protect the SEI film. Therefore, the isolation film is applied to the battery to reduce the expansion of the silicon negative electrode and avoid gas production.

[0008] In addition, nano-scale lithium halide is used in the raw materials of the modified electrode, which can replace the ceramic coating on the surface of the base membrane to ensure that the isolation membrane has good chemical and electrochemical stability, high thermal stability, and a certain ionic conductivity in the electrolyte. It can also realize the exchange of lithium ions with the positive electrode, negative electrode and electrolyte.

[0009] As an embodiment of the first aspect, the thermal stability temperature of the first modified electrode coating exceeds 130° C. to ensure the thermal stability of the first modified electrode coating. As an embodiment of the first aspect, the lithium ion diffusion coefficient of the first modified electrode coating in the liquid phase is 10 －8 ~10 －12 cm 2 / s range to ensure the movement speed of lithium ions, which is beneficial to improve the charging speed.

[0010] As an embodiment of the first aspect, the nanoscale lithium halide includes one or more of lithium fluoride, lithium chloride, lithium bromide, and lithium iodide. These nanoscale lithium halides can greatly increase the strength and thermal stability of the isolation membrane, have a certain ionic conductivity in the electrolyte, and can also exchange with lithium ions in the positive electrode, the negative electrode, and the electrolyte.

[0011] As an embodiment of the first aspect, a second modified electrode coating is provided on the surface of at least one side of the base film, and the second modified electrode coating includes one or both of nano inorganic lithium compounds and nano ceramic oxides. With this structure, on the one hand, the SEI film can be protected by the first modified electrode coating, and on the other hand, the mechanical strength and thermal stability of the isolation film can be enhanced by the second modified electrode coating.

[0012] As an embodiment of the first aspect, the first modified electrode coating is disposed on the first surface of the base film, and the second modified electrode coating is disposed on the second surface of the base film, and the first surface and the second surface are two opposite sides of the base film. The mechanical properties and thermal stability of the isolation film can be improved.

[0013] As an embodiment of the first aspect, the first modified electrode coating is disposed on the surface of one side of the base membrane, and the second modified electrode is disposed between the base membrane and the first modified electrode coating. This structure can improve the mechanical properties and thermal stability of the isolation membrane.

[0014] As an embodiment of the first aspect, the first modified electrode coating is respectively arranged on both sides of the base membrane. The first modified electrode coating can directly contact the surface of the base membrane or be indirectly arranged on the surface of the base membrane, thereby increasing the adjustable space of structure manufacturing.

[0015] As an embodiment of the first aspect, the first modified electrode coating is respectively disposed on the first surface and the second surface opposite to the base film. This structure can not only protect the negative electrode, but also play a certain protective role on the positive electrode.

[0016] As an embodiment of the first aspect, the isolation membrane includes a layer of a second modified electrode, and the second modified electrode is arranged between the first surface and the first modified electrode coating, or the second modified electrode is arranged between the second surface and the first modified electrode coating.

[0017] As an embodiment of the first aspect, the isolation membrane includes two layers of second modified electrode coating, wherein one layer of second modified electrode coating is arranged between the first surface and the first modified electrode coating, and the other layer of second modified electrode coating is arranged between the second surface and the first modified electrode coating.

[0018] As an embodiment of the first aspect, the first modified electrode coating further includes a conductive agent and / or a binder to improve the adhesion and conductivity of the first modified electrode coating.

[0019] As an embodiment of the first aspect, the mass ratio of the active material is between 50-97%, the mass ratio of the conductive agent is between 1-20%, the mass ratio of the nano-inorganic lithium compound is between 0-40%, the mass ratio of the binder is between 1-20%, and the rest is solvent.

[0020] As an embodiment of the first aspect, the conductive agent includes one or more of conductive carbon black, acetylene black, and carbon nanotubes.

[0021] As an embodiment of the first aspect, the binder also includes one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyethylene oxide, polypropylene oxide, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, and polytetrafluoroethylene.

[0022] As an embodiment of the first aspect, the second modified electrode coating also includes a binder, the mass ratio of the nano-ceramic oxide is between 0-90%, the mass ratio of the inorganic lithium compound is between 0-40%, the mass ratio of the binder is between 1-20%, and the rest is solvent.

[0023] As an embodiment of the first aspect, the nano-inorganic lithium compound includes one or more of nano-scale lithium halide, tantalum-doped lithium lanthanum zirconium oxide, and lithium lanthanum zirconium oxide.

[0024] As an embodiment of the first aspect, the nano ceramic oxide includes: one or more of silicon oxide, boehmite, aluminum oxide, zirconium oxide, zinc oxide and titanium oxide.

[0025] In a second aspect, the present application further discloses a bare battery cell, comprising: a positive electrode plate, a negative electrode plate and an isolation membrane arranged between the positive electrode plate and the negative electrode plate, the isolation membrane is the isolation membrane explained in the first aspect embodiment, and the first modified electrode coating of the isolation membrane faces the negative electrode plate.

[0026] In a third aspect, the present application further discloses a battery cell, comprising: a shell, and a bare battery cell and an electrolyte disposed in the shell, wherein the bare battery cell comprises the bare battery cell explained in the embodiment of the second aspect.

[0027] In a fourth aspect, the present application further discloses a battery, comprising: a protection plate, and a battery cell encapsulated by the protection plate, wherein the battery cell comprises the battery cell explained in the embodiment of the third aspect.

[0028] In a fifth aspect, the present application also discloses an electronic device, comprising the battery explained in the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the internal structure of a lithium-ion battery in some embodiments;

[0030] Figure 2 The structure of the isolation membrane of the present invention is shown in FIG. Figure 1 ;

[0031] Figure 3 A schematic diagram of the structure of a lithium-ion battery according to an embodiment of the present application;

[0032] Figure 4 The structure of the isolation membrane of the present invention is shown in FIG. Figure 2 ;

[0033] Figure 5 The structure of the isolation membrane of the present invention is shown in FIG. Figure 3 ;

[0034] Figure 6 The structure of the isolation membrane of the present invention is shown in FIG. Figure 4 ;

[0035] Figure 7 The structure of the isolation membrane of the present invention is shown in FIG. Figure 5 ;

[0036] Figure 8 The structure of the isolation membrane of the present invention is shown in FIG. Figure 6 ;

[0037] Fig. 9 The structure of the isolation membrane of the present invention is shown in FIG. Figure 7 ;

[0038] Fig.10 The structure of the isolation membrane of the present invention is shown in FIG. Figure 8 .

[0039] Reference numerals:

[0040] Silicon negative electrode 10; SEI film 11; isolation film 20 ′ (in some embodiments); positive electrode 30; isolation film 20 (in this application); first modified electrode coating 21; base film 22; second modified electrode coating 23. DETAILED DESCRIPTION

[0041] The following will provide a clear and complete description of the various embodiments of the present application in conjunction with the accompanying drawings.

[0042] In order to facilitate understanding of the technical solution of the present application, the technical problem to be solved by the present application is first analyzed and explained in conjunction with the structure of a lithium-ion battery.

[0043] refer to Figure 1 , Figure 1 Schematic diagram of the internal structure of a lithium-ion battery in some embodiments is shown. Figure 1 As shown, the lithium-ion battery includes a positive electrode 30, a silicon negative electrode 10 (negative electrode), a separator 20', and an aluminum-plastic film or a metal shell (not shown) wrapped on the outside. Among them, an electrolyte is also injected into the liquid lithium-ion battery. During the first charge and discharge process of the lithium-ion battery, the silicon negative electrode 10 reacts with the electrolyte at the solid-liquid interface to form a passivation layer covering the surface of the silicon negative electrode, namely, the SEI film 11. The SEI film 11 can better protect the silicon negative electrode and prevent the electrolyte from reacting with the silicon negative electrode (producing gas) to damage the silicon negative electrode.

[0044] Since the SEI film 11 will be destroyed due to the excessive expansion of the silicon negative electrode, the SEI film 11 will be broken, and the new part of the silicon negative electrode 10 will be exposed and react with the electrolyte to generate a new SEI film (repair process). In this way, a vicious cycle of continuous destruction and repair of the SEI film will occur, which will consume both the silicon negative electrode and the electrolyte. In some schemes, in order to solve the problems of excessive expansion and gas production of the silicon negative electrode 10, some additives that improve expansion and inhibit gas production are added to the electrolyte. For example, a linear polyolefin compound with a special structure is used as an additive to inhibit the expansion of the silicon negative electrode. A stable SEI film is formed by polymerization reaction on the surface of the silicon negative electrode through double bond functional groups to improve the stability of the interface between the silicon negative electrode and the electrolyte. At the same time, the additive can also be used as a film-forming component to increase the content of organic components in the protective film, improve the toughness of the protective film, inhibit the rupture and regeneration of the protective film, thereby inhibiting gas production during the electrolyte circulation process and the expansion of the silicon negative electrode. However, when additives are added to the electrolyte, the conductivity of the electrolyte will decrease, thereby slowing down the migration speed of lithium ions, and ultimately affecting the fast charging performance of the battery.

[0045] In other embodiments, a layer of lithium titanate modified electrode can be arranged on the surface of the silicon negative electrode, and the SEI film can be wrapped from the outside by the lithium titanate modified electrode, so as to protect the SEI film. Furthermore, the side reaction between the silicon negative electrode and the electrolyte can be prevented to avoid the continuous destruction and repair of the SEI film, thereby improving the gas production during the low-potential storage and circulation of the silicon negative electrode. However, the study found that there are several problems when the lithium titanate modified electrode is directly arranged on the surface of the silicon negative electrode:

[0046] First, the thickness consistency of the silicon negative electrode itself is poor. When the thickness and weight consistency of the lithium titanate modified electrode is poor, the overall thickness and weight consistency of the silicon negative electrode will be even worse.

[0047] Secondly, the solvent in the lithium titanate electrode slurry can easily penetrate into the interior of the silicon negative electrode, causing swelling and thickness expansion of the silicon negative electrode. In addition, the solute in the lithium titanate electrode slurry can also penetrate into the silicon negative electrode due to the dissolution of the silicon negative electrode, ultimately making the internal composition of the silicon negative electrode uneven.

[0048] Thirdly, as for the entire negative electrode, it is equivalent to increasing the thickness of the negative electrode, thereby affecting the energy density of the battery.

[0049] In order to solve the above technical problems, the present application provides an isolation membrane, and the modified electrode is arranged on the surface of the base membrane of the isolation membrane, so as to avoid the above three problems that the lithium titanate modified electrode directly increases on the silicon negative electrode, namely. It can avoid the problem that the thickness of the silicon negative electrode is poor, swelling and the internal composition of the silicon negative electrode are uneven due to the modified electrode being directly arranged on the surface of the isolation membrane. In addition, the isolation membrane with the modified electrode, in the process of hot pressing in the preparation of the battery, the modified electrode is in contact with the surface of the silicon negative electrode, which can protect the SEI film, reduce the expansion of the silicon negative electrode, reduce the probability of the SEI film being destroyed, and avoid gas production. In addition, nano-scale lithium halide is used in the raw material of the modified electrode, and the ceramic coating on the surface of the base membrane can be replaced to ensure that the chemical stability and electrochemical stability of the isolation membrane are good, the thermal stability is high, and it has a certain ionic conductivity in the electrolyte, and it can also achieve exchange with lithium ions in the positive electrode, the negative electrode and the electrolyte.

[0050] In the following embodiments, two major scenarios and eight structural variations of the isolation membrane are used as examples to explain the structure, working principle, etc. of a first modified electrode coating disposed on the surface of at least one side of the base membrane.

[0051] The first scenario is that only the first modified electrode coating is disposed on the base film of the isolation film. The second scenario is that both the first modified electrode coating and the second modified electrode coating are disposed on the base film of the isolation film.

[0052] It should be noted that, in the embodiments of the present application, the first modified electrode coating is disposed on one side or both sides of the base film. The first modified electrode coating may be directly disposed on the surface of the base film, or other coatings may be disposed between the first modified electrode coating and the surface of the base film.

[0053] The following describes isolation films with different structures and corresponding preparation methods in two scenarios of the embodiments of the present application in conjunction with the accompanying drawings.

[0054] The first structure in the first scenario: only one layer of the first modified electrode coating is provided on the base film of the isolation film.

[0055] refer to Figure 2 , Figure 2 FIG. 1 is a schematic diagram showing the structure of an isolation membrane according to an embodiment of the present application. Figure 2 As shown, the isolation film 20 includes a base film 22, and the base film 22 is formed into a sheet structure including two surfaces. A first modified electrode coating 21 is provided on the first surface of the base film 22, and the first modified electrode coating 21 includes nano-scale lithium halide and active materials. Among them, the active material includes lithium titanate and / or carbon-coated lithium titanate.

[0056] In the process of preparing a bare cell, cell or lithium-ion battery, the first modified electrode coating 21 and the silicon negative electrode 10 (negative electrode plate) are subjected to a process such as hot pressing to attach the first modified electrode coating 21 to the silicon negative electrode 10. Figure 1 The protection of the SEI film 11) shown can effectively reduce the expansion of the silicon negative electrode 10 and avoid gas generation.

[0057] In addition, since the first modified electrode coating 21 includes not only active materials of lithium titanate and / or carbon-coated lithium titanate, but also nano-scale lithium halide, the first modified electrode coating 21 composed of such raw materials, on the one hand, can replace the ceramic coating on the surface of the isolation membrane due to the characteristics of high mechanical strength and good thermal stability of inorganic halides, thereby improving the mechanical strength and thermal stability of the isolation membrane base membrane. On the other hand, inorganic halides have a high lithium ion diffusion coefficient, which can increase the lithium ion transmission speed of the electrolyte and further improve the fast charging capability of the battery.

[0058] In addition, lithium titanate itself is non-flammable and has the characteristics of a "semiconductor". When lithium ions leave the lithium titanate material, the lithium titanate material will be insulated. This characteristic gives the lithium titanate material a "self-contained short-circuit protection" function. When the isolation membrane shrinks or breaks, the positive and negative electrodes contact each other and an internal short circuit occurs. The lithium ions in the lithium titanate negative electrode will leave the lithium titanate material under the action of the short circuit circuit, and the lithium titanate material that has lost lithium ions will become an insulator, automatically preventing the short circuit from occurring, thereby realizing the "self-protection function of the battery during a short circuit". In addition, the lithium titanate material also has an insulating function when it is not deintercalating lithium.

[0059] Therefore, the first modified electrode coating prepared by adding inorganic nano lithium halide to lithium titanate and / or carbon-coated lithium titanate can not only replace the ceramic coating on the surface of the isolation membrane, but also has the function of reducing the continuous destruction and repair of the SEI film on the negative electrode surface. In this way, the probability of the silicon negative electrode continuously reacting with the electrolyte can be reduced, and the excessive expansion and gas production of the silicon negative electrode can be avoided, which is conducive to maintaining the energy density of the silicon negative electrode and extending the service life of the lithium-ion battery.

[0060] In one embodiment of the present application, the temperature of the thermal stability of the first modified electrode coating can exceed 130°C, thereby improving the thermal stability of the first modified electrode coating. The lithium ion diffusion coefficient of the first modified electrode coating in the liquid phase can be between 10 －8 ~10 －12 cm 2 / s range, the movement speed of lithium ions can be increased and the charging speed can be improved.

[0061] In one embodiment of the present application, the nanoscale lithium halide may include one or more of lithium fluoride, lithium chloride, lithium bromide, and lithium iodide. These nanoscale lithium halides can greatly increase the strength and thermal stability of the isolation membrane, and have a certain ionic conductivity in the electrolyte. It can also achieve exchange with lithium ions in the positive electrode, the negative electrode, and the electrolyte.

[0062] It should be noted that in the embodiments of the present application, the nano lithium halide has a certain ionic conductivity in the liquid electrolyte, and can realize the ability to exchange with the positive electrode, the negative electrode and the lithium ions in the electrolyte. In addition, the nano lithium halide has high thermal stability, is not prone to decomposition reaction, and can withstand high temperature environments of at least 300°C. Moreover, the nano lithium halide has good chemical stability and electrochemical stability, and does not react chemically with solvents, electrode materials, isolation membranes, etc., and is also required to have a high oxidation potential and a low reduction potential. Therefore, when some other inorganic lithium compounds also have these characteristics, they can also be applied in the present application, for example, tantalum-doped lithium lanthanum zirconium oxide (Li 6.4 Ln3Z 1.4 Ta 0.6 O 12 , LLZTO), lithium lanthanum zirconium oxide (Li7La3Zr2O 12 , LLZO) and other inorganic lithium compounds, etc. This ensures that the separator has high mechanical properties and high thermal stability, and contains lithium ions inside, which can assist the lithium ions moving from the positive electrode to be effectively relayed, increase the movement speed of lithium ions, and thus ensure the fast charging capability of the battery.

[0063] In some embodiments, the first modified electrode coating 21 also includes a conductive agent and / or a binder. Among them, the binder can effectively improve the bonding performance of the first modified electrode coating, which is conducive to the adhesion and fixation with the base film 22, and improves the stability of the isolation film 20. In addition, it can also make the first modified electrode coating 21 and the silicon negative electrode 10 more closely fit during the hot pressing process, which is conducive to the protection of the SEI film. The conductive agent can improve the conductivity of the first modified electrode coating 21 and increase the transfer speed of electrons.

[0064] In some embodiments, the conductive agent may include one or more of conductive carbon black, acetylene black, and carbon nanotubes. These conductive agents have good electrical conductivity and are beneficial to improving the electrical conductivity of the first modified electrode coating.

[0065] In some embodiments, the binder may also include one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyethylene oxide, polypropylene oxide, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, and polytetrafluoroethylene. These binders have good bonding effects and improve the overall stability of the first modified electrode coating and the isolation membrane.

[0066] In some embodiments, the components in the first modified electrode coating 21 account for the total raw material mass. According to the raw material mass ratio, the mass ratio of the active material is between 50-97%, for example, the mass ratio of the active material is 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc. The mass ratio of the conductive agent is between 1-20%, for example, the mass ratio of the conductive agent is 3%, 5%, 7%, 10%, 12%, 15%, 17%, 19%, etc. The mass ratio of nano-lithium halide is between 0.1-40%, for example, the mass ratio of nano-lithium halide is 1%, 3%, 5%, 7%, 10%, 13%, 15%, 17%, 20%, 22%, 25%, 30%, 33%, 36%, 36% or 38%, etc. The mass ratio of the binder is between 1% and 20%, for example, the mass ratio of the binder is 3%, 5%, 7%, 10%, 13%, 15%, 17% or 19%, etc. In addition to the above-mentioned components, the remaining components in the first modified electrode coating 21 are solvents. In the embodiment of the present application, the solvent may include water, acetone, ethanol or N-methylpyrrolidone.

[0067] The first modified electrode coating prepared according to the above-mentioned mass ratio of the component raw materials can not only replace the existing ceramic coating on the surface of the isolation membrane, thereby improving the mechanical strength and thermal stability of the isolation membrane, but also greatly improve the lithium ion transmission speed of the electrolyte, thereby further improving the fast charging capability of the battery.

[0068] In some embodiments of the present application, the base film can be composed of one or more of polyethylene (PE), polypropylene (PP), a three-layer composite of polypropylene, polyethylene and polypropylene, polyimide (PI), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polypropylene oxide (PPO), poly vinylidene fluoride-hexafluoropropylene (PVDF-HFP), etc.

[0069] Below Figure 2 The preparation process of the isolation film shown is described.

[0070] The above components, such as lithium titanate and / or carbon-coated lithium titanate, conductive agent, binder, nano halide and solvent are mixed according to mass ratio. Next, solid-liquid mixed layer slurry is obtained by physical stirring and mixing, and the solid-liquid mixed layer slurry is applied on the first surface of the base film. The ceramic coating in some existing solutions is continuously applied on the second surface of the base film, and then the isolation film is obtained after drying.

[0071] In some embodiments of the present application, the coating method can be gravure printing, transfer coating, extrusion coating, etc., wherein the coating thickness of a first modified electrode coating 21 is 1-15 micrometers (micrometre, um), for example, 2um, 5um, 7um, 10um, 12um or 15um, etc. This thickness can not only play a role in protecting the SEI film, but also have good mechanical strength and thermal stability, and can make lithium ions migrate better, ensure the migration speed of lithium ions, and meet the demand of the charge and discharge performance of the battery. When the first modified coating is too thick, it is not conducive to the migration speed of lithium ions, but affects the charge and discharge performance of the battery.

[0072] When the above Figure 2 When the separator is applied to a lithium-ion battery, the first modified electrode coating 21 will be attached to the SEI membrane to protect the SEI membrane. Figure 3 The structure of the lithium ion battery shown in the figure will be described below with respect to the structure of the separator in the lithium ion battery.

[0073] Combination Figure 2 And refer to Figure 3 , Figure 3 FIG. 1 is a schematic diagram showing the structure of a lithium-ion battery according to an embodiment of the present application. Figure 3 As shown, the lithium ion battery includes a positive electrode 30, a silicon negative electrode 10 (negative electrode), a separator 20, and an aluminum foil wrapped around the positive electrode 30 and the silicon negative electrode 10. Among them, the surface of the separator 20 is a first modified electrode coating 21, and the surface of the silicon negative electrode 10 is formed with a SEI film 11. The first modified electrode coating 21 is attached to the surface of the SEI film 11, so that the transition expansion of the SEI film 11 can be better protected. That is, it can effectively avoid the problem of excessive expansion of the silicon negative electrode during the charge and discharge process at a lower potential (below 3.0V), thereby reducing the volume energy density of the lithium ion battery, which is conducive to improving the service life of the lithium ion battery. In addition, once the SEI film 11 is damaged, the first modified electrode coating 21 can serve as a membrane to protect the silicon negative electrode, thereby preventing the electrolyte from having side reactions with the silicon negative electrode as much as possible, and also protecting the silicon negative electrode itself.

[0074] In the description of the isolation membrane of the first embodiment, a first modified electrode coating is provided on a single side surface of the base membrane of the isolation membrane. In some embodiments, the upper and lower surfaces of the base membrane of the isolation membrane 20 can be provided with a first modified electrode coating respectively.

[0075] The second structure in the first scenario: the first modified electrode coating is disposed on both sides of the base film of the isolation film (the first modified electrode coating is directly disposed on both side surfaces of the base film).

[0076] refer to Figure 4 , Figure 4 The structure of an isolation film according to an embodiment of the present invention is shown in FIG. Figure 2 .like Figure 4 As shown, the isolation film 20 includes a base film 22 and a first modified electrode coating layer 21 disposed on the upper surface (first surface) and the lower surface (second surface) of the base film 22 .

[0077] In the embodiments of the present application, the composition, content, thickness and preparation method of each raw material of each layer of the first modified electrode coating 21 can refer to Figure 2 The first modified electrode coating in the separator is shown.

[0078] In the embodiment of the present application, Figure 4 The battery prepared by the isolation membrane of the structure shown can not only obtain Figure 2 It has the same technical effect as the separator in the battery. In addition, it can also play a certain protective role for the positive electrode.

[0079] In the first scenario, the description is mainly directed to the structure including the first modified electrode coating 21 in the isolation membrane. In the second scenario, the isolation membrane 20 may include not only the first modified electrode coating 21, but also the second modified electrode coating. The second modified electrode coating may include one or a mixture of nano inorganic lithium compounds and nano ceramic oxide species. The second modified electrode coating of this material is conducive to improving the mechanical strength and thermal stability of the isolation membrane.

[0080] In conjunction with the second scenario, modification examples of isolation membranes with different structures are described below.

[0081] In the first structure of the second scenario, the isolation membrane includes a first modified electrode coating layer and a second modified electrode coating layer, and the two modified electrode layers are respectively arranged on both sides of the base membrane.

[0082] refer to Figure 5 , Figure 5 The structure of the isolation film of one embodiment of the present application is shown in FIG. Figure 3 .like Figure 5As shown, the isolation membrane 20 includes a base membrane 22, a first modified electrode coating 21 disposed on the first surface of the base membrane 22, and a second modified electrode coating 23 disposed on the second surface. The second modified electrode coating 23 may include one or a mixture of nano-inorganic lithium compounds and nano-ceramic oxides. Since such materials have high mechanical strength and thermal stability, the second modified electrode coating 23 may improve the mechanical strength and thermal stability of the isolation membrane. In addition, Figure 5 The first modified electrode coating 21 in the structure shown can protect the SEI film to avoid the problem of excessive expansion and gas generation of the silicon negative electrode. It should be noted that the working principle of the first modified electrode coating 21 can be referred to Figure 2 The description of the first modified electrode coating is not repeated here.

[0083] In some embodiments, the nano inorganic lithium compound may include, but is not limited to, one or more of nano lithium halide, tantalum doped lithium lanthanum zirconium oxide, and lithium lanthanum zirconium oxide. The lithium halide may be one or more of lithium fluoride, lithium chloride, lithium bromide, and lithium iodide.

[0084] Nano-ceramic oxides may include, but are not limited to, one or more of silicon oxide (SiO2), boehmite (AlOOH), aluminum oxide (Al2O3), zirconium oxide (ZrO2), zinc oxide (ZnO), titanium oxide (TiO2), etc.

[0085] Using the above materials as the second modified electrode coating 23 can improve the mechanical properties and thermal stability of the isolation membrane.

[0086] In some embodiments, the first modified electrode coating 23 further includes a binder, wherein the binder can effectively improve the bonding performance of the second modified electrode coating, facilitate the adhesion and fixation with the base film 22, and improve the stability of the isolation film 20.

[0087] In some embodiments, the binder may also include one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyethylene oxide, polypropylene oxide, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate and polytetrafluoroethylene. These binders have good bonding effect and improve the overall stability of the first modified electrode coating and the isolation membrane.

[0088] In some embodiments, the components in the second modified electrode coating 23 account for the total raw material mass. According to the raw material mass ratio, the mass ratio of the nano ceramic oxide is between 0-90%, for example, 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%, etc. The mass ratio of the inorganic lithium compound is between 0-40%, for example, 5%, 10%, 15%, 20%, 25%, 30% or 35%, etc. In addition, in the second modified electrode coating 23, the mass ratio of the binder is between 1-20%, and the remaining components are solvents.

[0089] It should be noted that the preparation process of the second modified electrode coating layer can refer to the preparation method of the first modified electrode coating layer, which will not be described in detail here.

[0090] In the following, multiple modification examples of the isolation membrane are described for the second scenario.

[0091] In the second structure of the second scenario, the isolation membrane includes a first modified electrode coating layer and a second modified electrode coating layer, and the two modified electrode layers are both arranged on a single side of the base membrane.

[0092] refer to Figure 6 , Figure 6 The structure of the isolation film of one embodiment of the present application is shown in FIG. Figure 4 .like Figure 6 As shown, the isolation membrane 20 includes a base membrane 22, a second modified electrode coating 23 disposed on the first surface of the base membrane, and a first modified electrode coating 21 disposed on the surface of the second modified electrode coating 23. Figure 5 Similarly, the SEI film can be protected by the first modified electrode coating 21 to prevent the silicon negative electrode from expanding too much and generating gas. The mechanical strength and thermal stability of the isolation film can be enhanced by the second modified electrode coating 23.

[0093] In the third structure of the second scenario, the isolation membrane includes one layer of the first modified electrode coating and two layers of the second modified electrode coating.

[0094] refer to Figure 7 , Figure 7 The structure of the isolation film of one embodiment of the present application is shown in FIG. Figure 5 .like Figure 7 As shown, the isolation film 20 includes a base film 22, and a second modified electrode coating 23 is respectively provided on the first surface and the second surface of the base film 22, and a first modified electrode coating 21 is provided on the second modified electrode coating 23 on the first surface of the base film 22. This structure can protect the SEI film through the first modified electrode coating 21 to prevent the silicon negative electrode from expanding too much and generating gas. The mechanical strength and thermal stability of the isolation film can be further enhanced by two layers of the second modified electrode coating 23.

[0095] In the fourth structure of the second scenario, the isolation membrane includes two layers of the first modified electrode coating and one layer of the second modified electrode coating.

[0096] refer to Figure 8 , Figure 8 The structure of the isolation membrane of each embodiment of the present application is shown in FIG. Figure 6 .like Figure 8 As shown, the isolation film 20 includes a base film 22, a first modified electrode coating 21 is arranged on the first surface of the base film 22, a second modified electrode coating 23 is arranged on the second surface of the base film, and the first modified electrode coating 21 is arranged on the second modified electrode coating 23. This structure can protect the SEI film of the silicon negative electrode through the first modified electrode coating 21 on the first surface to prevent the silicon negative electrode from expanding too much and producing gas. The first modified electrode coating 21 on the second surface can also protect the positive electrode to a certain extent. In addition, the mechanical strength and thermal stability of the isolation film can be improved by the second modified electrode coating 23.

[0097] The fifth structure in the second scenario is another situation in which the isolation membrane includes two layers of the first modified electrode coating and one layer of the second modified electrode coating.

[0098] refer to Fig. 9 , Fig. 9 The structure of the isolation film of each embodiment of the present application is shown in FIG. Figure 7 .like Fig. 9 As shown, the isolation membrane 20 includes a base membrane 22, a second modified electrode coating 23 is disposed on the first surface of the base membrane 22, and a first modified electrode coating 21 is disposed on the surface of the second modified electrode coating 23. The first modified electrode coating 21 is disposed on the second surface. This structure can achieve Figure 8 The effect of the structure shown is that the SEI film of the silicon negative electrode is protected by the first modified electrode coating 21 on the first surface to prevent the silicon negative electrode from expanding too much and producing gas. The positive electrode can also be protected to a certain extent by the first modified electrode coating 21 on the second surface. In addition, the mechanical strength and thermal stability of the isolation membrane can be improved by the second modified electrode coating 23.

[0099] In the sixth structure of the second scenario, the isolation membrane includes two layers of the first modified electrode coating and two layers of the second modified electrode coating.

[0100] refer to Fig.10 , Fig.10 The structure of the isolation film of one embodiment of the present application is shown in FIG. Figure 8 .like Fig.10As shown, the isolation film 20 includes a base film 22, on which a second modified electrode coating 23 is respectively provided on the first surface and the second surface of the base film 22, and on which a first modified electrode coating 21 is respectively provided on the surfaces of the two layers of the second modified electrode coating 23. This structure can further improve the mechanical strength and thermal stability of the isolation film through the two layers of the second modified electrode coating 23, and the SEI film of the silicon negative electrode can be protected respectively through the first modified electrode coating 21 on both sides, and the positive electrode can also be protected.

[0101] It should be noted that the first modified electrode coating in the above-mentioned variations corresponds to the composition of each raw material, and the content, thickness, preparation method, etc. can all refer to the description of the first modified electrode coating in the first structure in the first scene. The second modified electrode coating corresponds to the composition of each raw material, and the content, thickness, preparation method, etc. can all refer to the description of the second modified electrode coating in the first structure in the second scene, which will not be repeated here.

[0102] In the embodiment of the present application, a bare battery cell is also disclosed, such as Figure 3 As shown, the bare cell includes a positive electrode 30 (positive electrode plate), a silicon negative electrode 10 (negative electrode plate), and a separator 20 disposed between the positive electrode 30 and the silicon negative electrode 10. The separator is Figure 2-Figure 10 The isolation membrane explained.

[0103] When preparing the separator, the coated separator is wound or laminated with the positive electrode plate and the negative electrode plate to form a bare cell. For a separator with a single-sided modified electrode, the first modified electrode should face the negative electrode plate during the winding or lamination process. For a separator with a double-sided modified electrode, the first modified electrode coating on either side should face the negative electrode plate during the winding or lamination process.

[0104] In addition, in order to achieve better results, in the embodiments of the present application, the bare cell can be hot-pressed, or the negative electrode and the isolation film containing the first modified electrode coating can be hot-pressed and composited first, so that the first modified electrode coating surface is in closer contact with the surface of the negative electrode plate. Since the isolation film in the bare cell has good chemical stability and electrochemical stability, high thermal stability, it can well protect the SEI film. Therefore, the battery prepared from the bare cell can also avoid the problems of excessive expansion of the negative electrode and excessive gas production, and the isolation film is conducive to maintaining the energy density of the battery and improving the life of the battery.

[0105] In the embodiment of the present application, a battery cell is also disclosed, including a shell, a bare battery cell and an electrolyte disposed in the shell, wherein the bare battery cell includes the bare battery cell of the above embodiment. The battery cell can avoid the problem of excessive expansion of the negative electrode and excessive gas production, is conducive to maintaining the energy density of the battery cell, and improves the life of the battery.

[0106] In the embodiment of the present application, a battery is also disclosed, including a protection plate, and a battery cell encapsulated by the protection plate, and the battery cell is the battery cell explained in the above embodiment. The bare battery cell can be encapsulated with an aluminum-plastic film, and a lithium-ion battery can be prepared through processes such as liquid injection, standing, formation, capacity division and aging. The battery has a high energy density, can avoid excessive expansion of the negative electrode and excessive gas production, and has a long service life.

[0107] In an embodiment of the present application, an electronic device is also disclosed, comprising the battery explained in the above embodiment. The electronic device has a long service life.

[0108] It should be noted that, in the above embodiments, the preparation methods and raw materials not mentioned can adopt the preparation methods and raw materials in the prior art, and this application will not describe them in detail.

[0109] In some embodiments of the present application, the electronic device may be, but is not limited to, a tablet phone, a foldable phone, a tablet personal computer, an e-book reader, a laptop computer, a personal digital assistant (PDA), a personal computer, a notebook, a vehicle-mounted device, a wearable device (such as a watch, a bracelet), a speaker, a headset, and other electronic devices. In addition, it can also be applied to other fields, such as the automotive field that requires batteries, and the present application does not limit the application fields and products.

[0110] The isolation film and preparation method of the present application are further described below in conjunction with specific embodiments.

[0111] Comparative example: The lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a LiFP6 electrolyte, a PE isolation membrane, etc.

[0112] The positive electrode is made of lithium cobalt oxide, conductive carbon black and polyvinylidene fluoride (PVDF) binder, and N-methylpyrrolidone (NMP) is used as a solvent and stirred evenly to obtain a positive electrode slurry, which is coated on the surface of an aluminum foil current collector by extrusion coating and dried to obtain a positive electrode.

[0113] The negative electrode is made of a mixture of graphite and silicon negative electrode (mass ratio: 95:5), conductive carbon black, styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC), and water is used as a solvent to stir and evenly obtain a negative electrode slurry. The slurry is coated on the surface of the copper foil current collector by extrusion coating, and the negative electrode is obtained after drying.

[0114] The isolation membrane is composed of a 5-micron PE base film and a 4um double-sided ceramic coating, wherein the ceramic coating is printed on both sides of the PE base film by mixing boehmite and binder PVDF in NMP solvent, and the coating thickness is 2 microns on one side and 4 microns on both sides.

[0115] The positive electrode, the negative electrode and the separator are wound into a bare cell and hot pressed, and then packaged with an aluminum-plastic film. After liquid injection, standing, formation, capacity division and aging, the battery in the comparative example is obtained.

[0116] The above-mentioned comparison cells were subjected to room temperature cycle test, and the test conditions were as follows:

[0117] 1) Test temperature: 25℃,

[0118] 2) Battery charging and discharging conditions: charging rate: 3C; charging upper limit voltage: 4.5V; discharging rate: 0.2C, discharging cut-off voltage: 2.7V.

[0119] 3) Maximum number of charge and discharge cycles: 500 times.

[0120] The test results are: the battery thickness expansion rate after 500 cycles is 38.2%, and the battery produces gas.

[0121] Example 1

[0122] Lithium-ion batteries are mainly composed of a positive electrode, a negative electrode, LiFP6 electrolyte and a PE isolation membrane.

[0123] 1) The positive and negative electrodes are the same as those in the comparative example. The isolation film and base film are the same as those in the comparative example.

[0124] 2) The modified electrode 1 is composed of lithium titanate, conductive carbon black, lithium fluoride and polyvinylidene fluoride binder, with the mass ratio being 86%:1%:10%:3% respectively, and N-methylpyrrolidone is used as solvent and stirred to obtain a solid-liquid mixed slurry 1.

[0125] 3) The prepared slurry 1 is coated on both sides of the isolation film base film by gravure printing, and after drying, an isolation film containing the first modified electrode 1 is formed, wherein the thickness of the modified electrode on one side is 2 microns and the thickness on both sides is 4 microns. The isolation film, the positive electrode and the negative electrode are wound into a bare cell and hot pressed at 85°C, and then encapsulated with an aluminum-plastic film. After liquid injection, standing, chemical formation, volume separation and aging, the following is obtained: Figure 4 An isolation membrane of the structure shown.

[0126] Under the same test conditions as the comparative example, the test results are as follows: the battery thickness expansion rate after 500 cycles is 7.5%, and the battery does not produce gas.

[0127] Example 2

[0128] The difference between Example 2 and Example 1 is that the lithium titanate modified electrode is changed from double-sided to single-sided, wherein the thickness of the modified electrode single-sided is 4 microns. During the winding process, the modified electrode faces the negative electrode surface. Other aspects are the same as Example 1. Figure 2 An isolation membrane of the structure shown.

[0129] Under the same test conditions as the comparative example, the test results are as follows: the battery thickness expansion rate after 500 cycles is 7.6%, and the battery does not produce gas.

[0130] Example 3

[0131] The difference between Example 3 and Example 1 is that there are two layers of modified electrodes on the surface of the base film, the bottom layer is the second modified electrode coating close to the surface of the base film, and the upper layer is the first modified electrode coating far from the surface of the base film. The first modified electrode coating has a single-sided thickness of 1 micron and a double-sided thickness of 2 microns, and the second modified electrode coating is composed of nano-boehmite powder and polyvinylidene fluoride binder, with a single-sided thickness of 1 micron and a double-sided thickness of 2 microns. Fig.10 An isolation membrane of the structure shown.

[0132] Under the same test conditions as the comparative example, the test results are as follows: the battery thickness expansion rate after 500 cycles is 9.7%, and the battery does not produce gas.

[0133] Example 4

[0134] The difference between Example 4 and Example 3 is that the isolation membrane base film is the same as Example 3, and the modified electrodes 1 and 2 are changed from double-sided to single-sided, wherein the thickness of each single side of the modified electrodes 1 and 2 is 3 microns. During the winding process, the modified electrode 1 faces the negative electrode surface, and the rest is the same as Example 1. Figure 6 The structure of the isolation membrane is shown.

[0135] Under the same test conditions as the comparative example, the test results are as follows: the battery thickness expansion rate after 500 cycles is 9.9%, and the battery does not produce gas.

[0136] Example 5

[0137] The difference between Example 5 and Example 4 is that the isolation membrane base film is the same as Example 4, the first modified electrode coating and the second modified electrode coating are respectively placed on the upper and lower sides of the base film, and the thickness of each side of the first modified electrode coating and the second modified electrode coating is 3 microns. During the winding process, the first modified electrode coating faces the negative electrode surface, and the rest is the same as Example 1. Figure 5 The structure of the isolation membrane is shown.

[0138] Under the same test conditions as the comparative example, the test results are as follows: the battery thickness expansion rate after 500 cycles is 9.9%, and the battery does not produce gas.

[0139] The main differences between the above comparative examples and the examples are listed in Table 1:

[0140] Table 1 List of test data for comparative examples and embodiments

[0141]

[0142] It can be seen from Table 1 above that after the isolation membrane of the embodiment of the present application is applied to the lithium-ion battery, the cycle expansion rate of the battery is significantly lower than 38.2% of the comparative example, and the battery of the present application does not produce gas, while the comparative example produces gas. This shows that the isolation membrane of the embodiment of the present application is applied to the battery, which can better protect the SEI membrane and avoid excessive expansion caused by the side reaction between the electrolyte and the silicon negative electrode, as well as the problem of gas production.

[0143] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0144] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0145] In the description of the present application, it should be noted that the terms "upper" and "lower" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0146] Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present application.

Claims

1. A separation film, characterized in that: include: a base film formed into a sheet-like structure including two surfaces; A first modified electrode coating is provided on the surface of at least one side of the base film, wherein the first modified electrode coating comprises nano-scale lithium halide and an active substance; Wherein, the active material includes at least one of lithium titanate and carbon-coated lithium titanate.

2. The isolation film according to claim 1, characterized in that: The thermal stability temperature of the first modified electrode coating exceeds 130°C.

3. The isolation membrane according to claim 1 or 2, characterized in that: The lithium ion diffusion coefficient of the first modified electrode coating in the liquid phase is 10 －8 ~10 －12 cm 2 / s range.

4. The isolation membrane according to any one of claims 1 to 3, characterized in that: The nano-scale lithium halide includes one or more of lithium fluoride, lithium chloride, lithium bromide, and lithium iodide.

5. The isolation film according to any one of claims 1 to 4, characterized in that: A second modified electrode coating is provided on the surface of at least one side of the base film, and the second modified electrode coating comprises one or both of nano-inorganic lithium compounds and nano-ceramic oxides.

6. The isolation film according to claim 5, characterized in that: The first modified electrode coating is disposed on the first surface of the base film, and the second modified electrode coating is disposed on the second surface of the base film. The first surface and the second surface are two opposite sides of the base film.

7. The isolation film according to claim 5, characterized in that: The first modified electrode coating is disposed on a surface of one side of the base film, and the second modified electrode is disposed between the base film and the first modified electrode coating.

8. The isolation film according to claim 5, characterized in that: The first modified electrode coating is respectively arranged on both sides of the base film.

9. The isolation film according to claim 8, characterized in that: The first modified electrode coating is directly disposed on the opposite first and second surfaces of the base film, respectively.

10. The isolation film according to claim 9, characterized in that: The isolation membrane includes a layer of the second modified electrode, and the second modified electrode is arranged between the first surface and the first modified electrode coating, or the second modified electrode is arranged between the second surface and the first modified electrode coating.

11. The isolation film according to claim 9, characterized in that: The isolation membrane includes two layers of the second modified electrode coating, wherein one layer of the second modified electrode coating is arranged between the first surface and the first modified electrode coating, and the other layer of the second modified electrode coating is arranged between the second surface and the first modified electrode coating.

12. The isolation film according to any one of claims 1 to 11, characterized in that: The first modified electrode coating also includes at least one of a conductive agent and a binder.

13. The isolation film according to claim 12, characterized in that: The mass ratio of the active material is between 50-97%, the mass ratio of the conductive agent is between 1-20%, the mass ratio of the nano inorganic lithium compound is between 0-40%, the mass ratio of the binder is between 1-20%, and the rest is solvent.

14. The isolation membrane according to claim 12 or 13, characterized in that: The conductive agent includes one or more of conductive carbon black, acetylene black, and carbon nanotubes.

15. The isolation membrane according to claim 12 or 13, characterized in that: The binder also includes one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyethylene oxide, polypropylene oxide, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, and polytetrafluoroethylene.

16. The isolation film according to claim 5, characterized in that: The second modified electrode coating also includes a binder, the mass ratio of the nano ceramic oxide is between 0-90%, the mass ratio of the inorganic lithium compound is between 0-40%, and the mass ratio of the binder is between 1-20%.

17. The isolation film according to claim 5, characterized in that: The nano inorganic lithium compound includes one or more of nano lithium halide, tantalum doped lithium lanthanum zirconium oxide, and lithium lanthanum zirconium oxide.

18. The isolation film according to claim 5, characterized in that: The nano ceramic oxide includes one or more of silicon oxide, boehmite, aluminum oxide, zirconium oxide, zinc oxide and titanium oxide.

19. A bare battery cell, characterized in that: include: A positive electrode, a negative electrode and a separator arranged between the positive electrode and the negative electrode, wherein the separator is the separator according to claims 1 to 18, and the first modified electrode coating of the separator faces the negative electrode.

20. A battery cell, characterized in that: include: housing, and A bare battery cell and an electrolyte are disposed in the shell, wherein the bare battery cell comprises the bare battery cell according to claim 19.

21. A battery, characterized in that: include: A protection plate, and a battery cell encapsulated by the protection plate, wherein the battery cell comprises the battery cell according to claim 20.

22. An electronic device, characterized in that: Comprising the battery of claim 21.

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