Electrochemical apparatus and electrochemical apparatus applying the same

Abstract

To provide an electrochemical device and an electronic device using the electrochemical device.SOLUTION: An electrochemical device includes an electrode sheet 10, the electrode sheet 10 includes a first current collector 11, a first electrode sheet protruding from the first current collector 11, a first active material layer 13 provided on at least one surface of the first current collector 11, and an insulating layer 14 provided along a side of the first current collector 11 closer to the first electrode sheet and adjacent to the first active material layer 13, the insulating layer 14 includes a first region 141 provided on a side closer to the first electrode sheet and a second region 142 provided farther from the first electrode sheet and adjacent to the first active material layer 13, the thickness of the insulating layer 14 in the first region 141 is smaller than the thickness of the insulating layer 14 in the second region 142. The electrochemical device according to the present application controls the ratio between the thickness of the insulating layer 14 and the thickness of the first active material layer 13 and the shape of the insulating layer 14 scraped thinly, thereby improving the uniformity of the force on the electrode sheet 10 during roll pressing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to electrochemical apparatus and electrochemical apparatus that utilizes the same. [Background technology]

[0002] As the demand for high-energy-density batteries increases, it is generally necessary to increase battery capacity by applying a heavy active material layer to the electrode sheet. However, a heavy coating (thick electrode) generally results in a larger active material layer, creating a relatively noticeable thickness difference between the insulating layer (used to prevent burrs) covering the electrode sheet edge and the active layer, affecting the appearance of the electrode sheet. Furthermore, the insulating coating slurry fluid undergoes a dual effect: expansion due to excess stress on the coating equipment surface and drifting due to slurry surface tension during the drying process, resulting in a thick edge morphology at the edges of the insulating coating. This thick edge of the insulating coating can lead to drum edge phenomena during electrode sheet winding, potentially causing electrode sheet breakage in severe cases. Simultaneously, when the electrode sheet is roll-pressed, the tension distribution of the electrode sheet becomes unbalanced, resulting in alignment that does not meet requirements and affecting the dimensions of the electrode sheet.

[0003] To solve this problem, conventional techniques involve making the insulating layer application area larger than the actual required size of the electrode when manufacturing the electrode, and then cutting off the thick edge region of the electrode sheet. However, making the insulating coating application area larger than the actual required size of the electrode and leaving a thick edge can lead to excessive waste of material. It is necessary for those skilled in the art to consider how to improve the appearance of the electrode sheet of a thick electrode and eliminate the drum edge phenomenon of the insulating layer, thereby meeting the demand for high energy density while simultaneously increasing the yield rate of battery products. [Overview of the project]

[0004] To solve the problem of excessive coating thickness on electrode sheets in the prior art, an embodiment of the present invention provides an electrochemical apparatus comprising an electrode sheet, the electrode sheet comprising a first current collector, a first electrode sheet protruding from the first current collector, a first active material layer provided on at least one surface of the first current collector, and an insulating layer provided along the side of the first current collector near the first electrode sheet and adjacent to the first active material layer, wherein the insulating layer includes a first region provided on the side near the first electrode sheet and a second region provided far from the first electrode sheet and adjacent to the first active material layer, the thickness of the insulating layer in the first region being less than the thickness of the insulating layer in the second region.

[0005] In a possible embodiment, the first region includes a first surface, the plane on which the first surface is located intersects with the plane on which the first current collector is located to form an acute angle α, the thickness of the second region is H, the width of the insulating layer is W, and W / H ≥ cotα.

[0006] In possible embodiments, the range of the acute angle α is 5° to 75°.

[0007] In possible embodiments, the thickness H of the second region is in the range of 20 μm to 100 μm, and the width W of the insulating layer is in the range of 1 mm to 10 mm.

[0008] In possible embodiments, the thickness L of the first active material layer is in the range of 30 μm to 200 μm.

[0009] In possible embodiments, the thickness of the second region is H, and the thickness H of the second region and the thickness L of the first active material layer satisfy the relationship 0.3 ≤ H / L ≤ 0.8.

[0010] In possible embodiments, the weight of the coating of the first active material layer is 0.06 mg / mm². 2 ~0.35 mg / mm³ 2 That is the case.

[0011] In a possible embodiment, the consolidation density of the first active material layer is 2 g / cc to 6 g / cc.

[0012] In a possible embodiment, the insulating layer includes inorganic particles containing at least one of boehmite, alumina, zirconia, boron oxide, or hexagonal boron nitride, and a binder containing at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride - hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate salt, or sodium carboxymethyl cellulose.

[0013] This application further provides an electronic device including the aforementioned electrochemical device.

[0014] Compared with the prior art, in the electrochemical device of this application, an insulating layer having a first region and a second region with different thicknesses is provided outside the first active material layer. The thickness of the second region closer to the first active material layer is greater than the thickness of the first region farther from the first active material layer. That is, when removing the thick - edge morphology by thinning the region near the edge of the electrode sheet but controlling so that this thinned region does not extend to the first active material layer, it avoids the loss of the active material in the first active material layer, increases the energy density of the electrochemical device, overcomes the problem of the drum edge of the electrode sheet by removing the thick - edge morphology, and reduces the thickness difference between the first active material layer and the insulating layer.

Brief Description of the Drawings

[0015] [Figure 1] It is a plan schematic view of the electrochemical device according to an embodiment of this application. [Figure 2] It is a plan schematic view of the electrode sheet of the electrochemical device according to an embodiment of this application. [Figure 3] It is a cross - sectional schematic view in the III - III direction of FIG. 2. [Figure 4] It is a perspective schematic view of the electronic device according to an embodiment of this application.

Modes for Carrying Out the Invention

[0016] Hereinafter, referring to the drawings, the content of the present application will be described more comprehensively. The drawings show exemplary embodiments of the present application. However, the present application can be implemented in many different forms and should not be construed as being limited to the exemplary embodiments described herein. These exemplary embodiments are provided to make the present application thorough and complete and to fully convey the scope of the present application to those skilled in the art. Like reference numerals represent the same or similar elements.

[0017] The terms used in this specification are only used to describe specific exemplary embodiments and are not intended to limit the present application. As used in this specification, unless the context clearly indicates otherwise, the singular forms "a", "one", and "this" are intended to include the plural forms as well. Further, as used in this specification, "comprising" and / or "including" and / or "having", integers, steps, operations, components, and / or components, and the presence or addition of one or more other features, regions, integers, steps, operations, components, components, and / or groups thereof are excluded.

[0018] Unless otherwise specifically defined, all terms (including technical terms and scientific terms) used in this specification have the same meaning as commonly understood by those of ordinary skill in the art to which this application pertains. Further, terms as defined in a general dictionary should be construed to have a meaning consistent with the meaning in the relevant art and the content of this application, and should not be construed in an idealized or overly formal sense unless explicitly defined otherwise.

[0019] Exemplary embodiments will be described below in relation to the drawings. Note that the components depicted in the drawings are not necessarily shown to scale, while the same or similar components are assigned the same or similar reference numerals or similar technical terms.

[0020] [[ID=j16]]Hereinafter, referring to the drawings, specific embodiments of the present application will be described in more detail.

[0021] As shown in Figure 1, one embodiment of the present invention provides an electrochemical apparatus 1 including an electrode sheet 10. In this embodiment, the present invention is described using a lithium-ion battery as an example, but the electrochemical apparatus 10 of the present invention is not limited to a lithium-ion battery.

[0022] Figure 2 is a partially enlarged schematic diagram of an electrode sheet 10 of an electrochemical apparatus 1 according to one embodiment of the present invention. As shown in the figure, the electrode sheet 10 comprises a first current collector 11, a first tab 12, a first active material layer 13, and an insulating layer 14. Here, the first tab 12 protrudes from the first current collector 11, the first active material layer 13 is provided on at least one side of the first current collector 11, and the insulating layer 14 is provided along the side of the first current collector 11 closest to the first tab 12 and adjacent to the first active material layer 13. The insulating layer 14 includes a first region 141 provided on the side closest to the first tab 12, and a second region 142 provided between the first region 141 and the first active material layer 13 and adjacent to the first region 141 and the first active material layer 13. The thickness of the insulating layer 14 located in the first region 141 is smaller than the thickness of the insulating layer 14 located in the second region 142, in a direction perpendicular to the surface on which the insulating layer 14 of the first current collector 11 is provided. In one embodiment, the fact that the thickness of the insulating layer 14 located in the first region 141 is smaller than the thickness of the insulating layer 14 located in the second region 142 means that the thickness of the insulating layer 14 located at each position in the first region 141 is smaller than the thickness of the insulating layer 14 located in the second region 142. In another embodiment, the fact that the thickness of the insulating layer 14 located in the first region 141 is smaller than the thickness of the insulating layer 14 located in the second region 142 means that the maximum thickness of the insulating layer 14 located in the first region 141 is smaller than the minimum thickness of the insulating layer 14 located in the second region 142.

[0023] An insulating layer 14 is provided on the outside of the first active material layer 13, having a first region 141 and a second region 142 of different thicknesses. The thickness of the second region 142, which is closer to the first active material layer 13, is greater than the thickness of the first region 141, which is further away from the first active material layer 13. In other words, the insulating layer 14 thins the region near the edge of the electrode sheet 10, but this thinning is controlled so that it does not extend to the first active material layer 13. When removing the thick edge morph, loss of active material from the first active material layer 13 is avoided, the energy density of the electrochemical apparatus 10 is increased, and the thick edge morph is removed, overcoming the drum edge problem of the electrode sheet 10 and reducing the thickness difference between the first active material layer 13 and the insulating layer 14.

[0024] In the positive electrode of the embodiment of the present invention, there are no particular restrictions on the positive electrode, as long as the objective of the present invention can be achieved. For example, the positive electrode usually includes a positive electrode current collector and a positive electrode active material layer. The positive electrode current collector is not particularly limited, but usually includes at least one of aluminum foil, aluminum alloy foil, or a composite current collector. The positive electrode active material layer includes a positive electrode active material, and the positive electrode active material is not particularly limited, and may include at least one of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based material, lithium cobalt oxide, lithium manganese oxide, lithium iron manganese phosphate, or lithium titanate.

[0025] In the negative electrode of the embodiment of the present invention, there are no particular restrictions on the negative electrode, as long as the objective of the present invention can be achieved. For example, the negative electrode usually includes a negative electrode current collector and a negative electrode active material layer. However, the negative electrode current collector is not particularly limited and may include at least one of copper foil, aluminum foil, aluminum alloy foil, and composite current collector. The negative electrode active material layer includes a negative electrode active material, and the negative electrode active material is not particularly limited and may include at least one of artificial graphite, natural graphite, mesocarbon microbeads, soft carbon, hard carbon, silicon, silicon carbon, lithium titanate, etc.

[0026] The electrode sheet 10 may be either a positive or negative electrode, and in this embodiment, an example in which the electrode sheet 10 is a positive electrode will be described. In contrast, the first active material layer 13 may be either a positive electrode active material layer or a negative electrode active material layer, and in this embodiment, an example in which the positive electrode active material layer is described will be described. In one embodiment, the first tab 12 protrudes from the first current collector 11, that is, the first tab 12 protrudes in a direction away from the central region of the first current collector 11 than the edge of the first current collector 11. In this embodiment, the protrusion of the first tab 12 from the first current collector 11 means that the first tab 12 is integral with the first current collector 11 and may be formed extending from the edge of the first current collector 11, and in other embodiments, the first tab 12 is not integral with the first current collector 11 and may be connected to the first current collector 11, for example by welding, before the insulating layer 14 is applied to the electrode sheet 10.

[0027] In one embodiment, the first active material layer 13 is provided on at least one surface of the first current collector 11, for example, the first active material layer 13 may be provided on the opposite surface of the first current collector 11.

[0028] In this embodiment, the insulating layer 14 is applied to the surface of the first current collector 11 and is adjacent to the first active material layer 13. The insulating layer 14 is provided on the edge of the first current collector 11 and covers at least the edge of the first current collector 11 after cutting, covering the cutting burr located on that edge and preventing the burr from piercing the separator. Furthermore, the insulating layer 14 also covers at least a portion of the boundary between the first current collector 11 and the first tab 12, covering the cutting burr at one end of the first tab 12 adjacent to the first current collector 11 and preventing the burr from piercing the separator.

[0029] As shown in Figure 3, the first region 141 has a first surface 143, and the surface on which the first surface 143 is located intersects with the surface on which the first current collector 11 is located to form an acute angle α, the thickness of the second region 142 is H, the width of the insulating layer is W, and W / H ≥ cotα.

[0030] In one embodiment, the cross-section along the thickness direction of the electrode sheet in the insulating layer 14 is trapezoidal. Specifically, the insulating layer 14 has a thickness substantially equal to that of the side adjacent to the first active material layer 13 (i.e., the second region 142). The insulating layer 14 has a first region 141 on the side away from the first active material layer 13 and close to the first tab 12. The thickness of the insulating layer 14 gradually decreases from the boundary between the first region 141 and the second region 142 towards the first tab 12 side until the first surface 143 intersects the first current collector 11 to form an acute angle α.

[0031] In one embodiment, if W / H < cotα, in the process of cutting the first current collector 11 to obtain the first tab 12, the cross-section along the thickness direction of the electrode sheet of the insulating layer 14 is not substantially trapezoidal but substantially triangular. That is, the portion of the first active material layer 13 close to the insulating layer 14 is removed, resulting in a decrease in the overall energy density of the electrochemical device 1 and energy loss, and there is a possibility that the boundary between the first active material layer 13 and the insulating layer 14 becomes blurred.

[0032] In one embodiment, the range of the acute angle α is 5° to 75°. If the acute angle α is smaller than 5°, there is a possibility that the insulating layer 14 cannot meet the requirement of this angle during the thinning process. If the acute angle α is larger than 75°, the average thickness of the insulating layer 14 in the first region 141 becomes too large, and there is a possibility that the end of the electrode sheet 10 bulges. In one embodiment, the acute angle α is obtained by using a CCD camera to acquire an image of the cross-section of the insulating layer 14 and performing angle measurement in the region corresponding to the acute angle α in the image.

[0033] In one embodiment, the thickness of the insulating layer 14, i.e., the thickness of the second region, can be measured using a fraction of a millimeter or a CCD camera. For example, a pole sheet 10 of a predetermined length is cut or selected, and at least one surface of this pole sheet 10 includes the cross-sections of the first region 141 and the second region 142. The thickness of the insulating layer 14 is determined by measuring the second region 142 on the pole sheet 10 multiple times using a fraction of a millimeter. For example, the thickness of the second region 142 is measured 15 times each, and then the average value of the multiple measurements is taken as the thickness of the second region 142. Alternatively, an image of the surface including the cross-sections of the first region 141 and the second region 142 is captured using a CCD camera. The thickness of the insulating layer 14 is obtained using a measuring instrument (e.g., software) that matches the CCD camera. Different images or different parts of the same image are repeatedly acquired multiple times (e.g., 15 times), and the average value of the multiple measured thicknesses is obtained to obtain the thickness of the insulating layer 14.

[0034] In one embodiment, the width of the insulating layer 14 can be measured using a CCD camera. For example, an image of the insulating layer 14, including a continuous first region 141 and a second region 142, can be captured using a CCD camera. Specifically, the image can be acquired using a CCD camera at low magnification, and the width of the insulating layer 14 can be obtained by setting both side edges of the insulating layer 14 using a measurement tool (e.g., software) that is compatible with the CCD camera. Different images or different parts of the same image can be acquired multiple times (e.g., 15 times), and the width of the insulating layer 14 can be obtained by calculating the average value of the thickness measured multiple times.

[0035] In one embodiment, the thickness H of the second region 142 is in the range of 20 μm to 100 μm, and the width W of the insulating layer 14 is in the range of 1 mm to 10 mm. If the thickness H of the second region 142 is less than 20 μm, the thickness of the insulating layer 14 becomes smaller than the length of a typical burr, and the burr cannot be effectively covered, potentially creating a short-circuit risk in the electrochemical apparatus 1. If the thickness of the second region 142 is greater than 100 μm, the electrode sheet 10 may not be able to meet the cold pressure parameter requirements.

[0036] In one embodiment, the thickness L of the first active material layer 13 is in the range of 30 μm to 200 μm. The thickness H of the second region 142 and the thickness L of the first active material layer 13 satisfy the relationship 0.3 ≤ H / L ≤ 0.8. If this ratio is too small and the insulating layer 14 is too thin, it cannot perform its role in preventing burrs, and if this ratio is too large and the insulating layer is too thick, it becomes difficult to achieve the set compaction density in the cold pressing process of the electrode sheet 10.

[0037] In one embodiment, the coating weight of the first active material layer 13 is 0.06 mg / mm². 2 ~0.35 mg / mm³ 2 That is the case.

[0038] In one embodiment, the weight of the first active material layer 13 or electrode sheet 10 per unit area is measured using a 1 / 10,000 analytical balance, and the weight of the coating is obtained by converting it to the following formula: Weight of coating = (Weight of electrode sheet - Weight of current collector) / Area of ​​electrode sheet, and the average value can be taken. 2 If the size is smaller, the energy density will be lower, making it difficult to meet the requirements, or problems such as particles and scratches will be more likely to occur in the first active material layer 13, or the coating weight will be 0.35 mg / mm². 2 If the thickness is too large, processing problems such as difficulty in drying or cracking may occur on the electrode sheet 10. Furthermore, the larger thickness makes the coating process more difficult, while the first active layer 13 (for example, the active material made of lithium iron phosphate) is prone to cracking, which is unfavorable for lithium ion diffusion and negatively affects the electrochemical cycle.

[0039] In one embodiment, the compaction density of the first active material layer 13 is 2 g / cc to 6 g / cc. In one embodiment, the weight of the first active material layer 13 or electrode sheet 10 per unit area may be measured using an analytical balance of 1 / 10,000, and the compaction density may be obtained using a formula such as (weight of insulating layer electrode sheet per unit area - weight of current collector) / thickness of insulating layer other than the base material, and the average value may be calculated. If the compaction density is too low (less than 2 g / cc), there is little active material per unit volume, so the energy density is low and it becomes difficult to meet the demand. If the compaction density is too high (greater than 6 g / cc), the porosity of the first active material layer 13 is too low, which weakens the ion transport capacity, the internal resistance (DCR) is too high, or the electrode sheet 10 becomes brittle, making it prone to band breakage during the cold pressing process.

[0040] In one embodiment, the insulating layer 14 comprises inorganic particles containing at least one of boehmite, alumina, zirconia, boron oxide, or hexagonal boron nitride, and a binder containing at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, or sodium carboxymethylcellulose.

[0041] The electrochemical apparatus of the present invention further comprises a separator, which separates the positive electrode and the negative electrode, prevents internal short circuits in the electrochemical apparatus, and allows free passage of electrolyte ions, thus playing a role in the electrochemical charge-discharge process. In this invention, there are no particular limitations on the separator as long as it can achieve the objectives of the present invention. For example, it may be at least one of the following: polyethylene (PE), polypropylene (PP)-based polyolefin (PO) separators, polyester films (e.g., polyethylene terephthalate (PET) films), cellulose films, polyimide films (PI), polyamide films (PA), spandex or aramid films, woven films, nonwoven films (nonwoven fabrics), microporous films, composite films, separator paper, laminate films, spun films, etc.

[0042] Furthermore, the separator may have a base layer and a surface treatment layer. The base layer may be a nonwoven fabric, film, or composite film having a porous structure, and the material of the base layer may include at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide. In one embodiment, a polypropylene porous film, a polyethylene porous film, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite film can be used. In one embodiment, a surface treatment layer is provided on at least one surface of the base layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic material.

[0043] Furthermore, for example, the inorganic layer may contain inorganic particles and a binder, and the inorganic particles are not particularly limited but may be at least one selected from, for example, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium sulfate, etc. The binder is not particularly limited and may be one or more selected from the group consisting of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate salt, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene. For example, the polymer layer contains a polymer, and the polymer material includes at least one of the following: polyamide, polyacrylonitrile, acrylic acid ester polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).

[0044] The electrochemical apparatus of the present invention further comprises an electrolyte, which may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte solution, and the electrolyte solution comprises a lithium salt and a non-aqueous solvent.

[0045] In one embodiment, when the electrochemical apparatus 10 is a lithium-ion battery, the lithium salt is one or more selected from LiPF6, LiBF4, LiAsF6, LiClO4, LiB(C6H5)4, LiCH3SO3, LiCF3SO3, LiN(SO2CF3)2, LiC(SO2CF3)3, LiSiF6, LiBOB, and lithium difluoroborate. LiPF6 can be used as the lithium salt because it provides high ionic conductivity and improves cycle characteristics.

[0046] Non-aqueous solvents may be carbonate compounds, carboxylic acid ester compounds, ether compounds, other organic solvents, or combinations thereof.

[0047] The carbonate compound may be a linear carbonate compound, a cyclic carbonate compound, a fluorinated carbonate compound, or a combination thereof.

[0048] Examples of the above-mentioned linear carbonate compounds include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), and combinations thereof. Examples of cyclic carbonate compounds include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), and combinations thereof. Examples of fluorinated carbonate compounds include fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, and combinations thereof.

[0049] Examples of the above carboxylic acid ester compounds include methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolatatone, decanolide, valerolactone, mevalonolactone, caprolactone, and combinations thereof.

[0050] Examples of the above ether compounds include dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane, 2-methyltetrahydrofuran, tetrahydrofuran, and combinations thereof.

[0051] Other examples of organic solvents include dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, phosphate esters, and combinations thereof.

[0052] The manufacturing process for the electrochemical apparatus 1 is well known to those skilled in the art, and there are no particular limitations in this application. For example, the electrochemical apparatus can be manufactured by a process in which a positive electrode and a negative electrode are stacked with a separator in between, wound, folded, or otherwise operated, then placed in a housing, and an electrolyte is injected into the housing and sealed. The separator used here is the separator provided in this application. In addition, if necessary, an overcurrent prevention element or lead plate may be placed in the housing to prevent pressure rise and overcharging / discharging inside the electrochemical apparatus.

[0053] As shown in Figure 4, this is a schematic perspective view of the electronic device 100 provided in the embodiment of the present application. The present application further provides an electronic device 100 comprising an electrochemical device 1. In Figure 4, only the electronic device 100 is shown as a mobile phone as an example, but in other embodiments, the electronic device 100 of the present application is not particularly limited and may be used as any conventionally known electronic device. In some embodiments, the electronic device 100 may include, but is not limited to, a notebook computer, a pen-input computer, a mobile PC, an e-book player, a mobile phone, a portable facsimile, a portable copier, a portable printer, a headset / stereo / earphone, a video camera, an LCD television, a portable cleaner, a portable CD player, a MiniDisc player, a transceiver, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, an electric assist bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flash, a camera, a large household storage battery, a lithium-ion capacitor, and the like.

[0054] COV test of the thickness of the polar sheet edge. 1) Remove the electrode sheet from the battery product in an environment of (25±3)℃. Wipe off any electrolyte remaining on the surface of the electrode sheet with dust-free paper. 2) Cut the electrode sheet to obtain an electrode sheet sample of a certain size. 3) Using a tenth of a thousandth of a second ruler, measure the thickness of the pole sheet edge on the side closest to the tab of the pole sheet sample in 2), sequentially test the thickness values ​​at 15 different points along the pole sheet edge, and calculate the COV value of the thickness values ​​at all test points.

[0055] Battery volumetric energy density test. 1) Under conditions of (25±3)℃, the battery is charged to 3.6V with a constant current, and then discharged to 2.5V at a rate of 0.5C to obtain the actual capacity Cap. 2) The battery discharge stage is E. 3) Measure the length, width, and height of the battery, taking 10 measurements on each side and taking the average value. The volume V = length * width * height. 4) Volumetric energy density VED = Cap * E / V. Example 1

[0056] <1-2. Preparation of positive electrode sheets> Lithium cobaltate, acetylene black, and polyvinylidene fluoride (PVDF), which are the positive electrode active materials, were mixed in a mass ratio of 94:3:3. Then, N-methylpyrrolidone (NMP) was added as a solvent to prepare a slurry with a solid content of 75%, which was then uniformly stirred. The slurry was uniformly applied to one side of a 12 μm thick aluminum foil, dried at 90°C, and cold-pressed to obtain a positive electrode sheet with a positive electrode active material layer thickness of 100 μm. The above process was repeated on the other side of this positive electrode sheet to obtain a positive electrode sheet with positive electrode active material layers coated on both sides. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the weight of the coating of the first active material layer is 0.2 mg / mm². 2 Therefore, the compaction density of the first active material layer is 2.0 g / cc.

[0057] An insulating layer is provided at the edge of the positive electrode active material layer on the side of the positive electrode sheet closest to the tab. Here, the insulating layer components (mass ratio) are PVDF and boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 20 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0058] The positive electrode sheet is cut to a specification of 74mm x 867mm, welded to the electrode sheet, and then used.

[0059] <1-3. Fabrication of the negative electrode sheet> Synthetic graphite, acetylene black, styrene-butadiene rubber, and sodium carboxymethylcellulose, which are the negative electrode active materials, were mixed in a mass ratio of 96:1:1.5:1.5. Deionized water was added as a solvent to prepare a slurry with a solid content of 70%, and it was uniformly stirred. The slurry was uniformly applied to one surface of an 8 μm thick copper foil, dried at 110°C, and cold-pressed to obtain a negative electrode sheet with a negative electrode active material layer of 150 μm thickness on one side. The above coating process was then repeated on the other surface of this negative electrode sheet to obtain a negative electrode sheet with negative electrode active material layers applied to both sides. The negative electrode sheet was cut to a specification of 74 mm × 867 mm, and the electrode sheets were welded together before use.

[0060] <1-5. Preparation of Electrolyte> In an environment with a water content of less than 10 ppm, non-aqueous organic solvents ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), propyl propionate (PP), and vinylene carbonate (VC) were mixed in a mass ratio of 20:30:20:28:2. Then, lithium hexafluorophosphate (LiPF6) was added to the non-aqueous organic solvent and uniformly dissolved to obtain an electrolyte, with a mass ratio of LiPF6 to non-aqueous organic solvent of 8:92.

[0061] <1-6 Manufacturing of Lithium-ion Batteries> The positive electrode sheet and the negative electrode sheet were wound, and a polyethylene (PE) film was used as a separator to separate between the positive electrode sheet and the negative electrode sheet, thereby fabricating an electrode assembly. The electrode assembly was placed in an aluminum plastic film packaging bag, moisture was desorbed at 80°C, the prepared electrolytic solution was injected, and a lithium ion battery was obtained through processes such as vacuum sealing, standing, forming, and shaping.

[0062] Example 2 Example 2 has the same lithium ion battery manufacturing process as Example 1, but there are differences in the composition parameters. Here, the thickness L of the positive electrode active material (the first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm 2 and the consolidation density of the first active material layer is 2.0 g / cc, the insulating layer component (mass ratio) is PVDF: boehmite = 40%: 60%, the thickness H of the second region of the insulating layer is 40 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0063] Example 3 Example 3 has the same lithium ion battery manufacturing process as Example 1, but there are differences in the composition parameters. Here, the thickness L of the positive electrode active material (the first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm 2 and the consolidation density of the first active material layer is 2.0 g / cc, the insulating layer component (mass ratio) is PVDF: boehmite = 40%: 60%, the thickness H of the second region of the insulating layer is 50 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0064] Example 4 Example 4 has the same lithium ion battery manufacturing process as Example 1, but there are differences in the composition parameters. Here, the thickness L of the positive electrode active material (the first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm 2The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 80 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0065] Example 5 Example 5 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 125 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 100 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0066] Example 6 Example 6 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 50 μm, the width W of the insulating layer is 1 mm, and cotα corresponding to the acute angle α is 1.

[0067] Example 7 Example 7 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 50 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0068] Example 8 Example 8 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 80 μm, the width W of the insulating layer is 10 mm, and cotα corresponding to the acute angle α is 1.

[0069] Example 9 Example 9 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 30 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0070] Example 10 Example 10 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 50 μm, the width W of the insulating layer is 10 mm, and cotα corresponding to the acute angle α is 0.3.

[0071] Example 11 Example 11 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 80 μm, the width W of the insulating layer is 10 mm, and cotα corresponding to the acute angle α is 1.

[0072] Example 12 Example 12 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 30 μm, and the coating weight of the first active material layer is 0.06 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 24 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0073] Example 13 Example 13 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 175 μm, and the coating weight of the first active material layer is 0.35 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 88 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 11.4.

[0074] Example 14 Example 14 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 88 μm, and the coating weight of the first active material layer is 0.35 mg / mm². 2 The compaction density of the first active material layer is 4.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 44 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0075] Example 15 Example 15 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 58 μm, and the coating weight of the first active material layer is 0.35 mg / mm². 2 The compaction density of the first active material layer is 6.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 30 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0076] Example 16 Example 16 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in composition parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are polyacrylic acid:zirconia = 30%:70%, the thickness H of the second region of the insulating layer is 50 μm, the width W of the insulating layer is 1.2 mm, and cotα corresponding to the acute angle α is 1.

[0077] Example 17 Example 17 has the same lithium-ion battery manufacturing flow as Example 1, but with differences in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer is 2.0 g / cc, the insulating layer components (mass ratio) are PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer is 87.5 μm, the width W of the insulating layer is 1 mm, and cotα corresponding to the acute angle α is 11.4.

[0078] Comparative Example 1 Comparative Example 1 has the same lithium-ion battery manufacturing flow as Example 1, but differs in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 30 μm, and the coating weight of the first active material layer is 0.045 mg / mm².2 The compaction density of the first active material layer was 1.5 g / cc, the insulating layer composition (mass ratio) was PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer was 30 μm, and the width W of the insulating layer was 1 mm. The insulating layer was not thinned.

[0079] Comparative Example 2 Comparative Example 2 has the same lithium-ion battery manufacturing flow as Example 1, but differs in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer was 2.0 g / cc, the insulating layer composition (mass ratio) was PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer was 50 μm, and the width W of the insulating layer was 1.2 mm. The insulating layer was not thinned.

[0080] Comparative Example 3 Comparative Example 3 has the same lithium-ion battery manufacturing flow as Example 1, but differs in compositional parameters. Here, the thickness L of the positive electrode active material (first active material layer) is 100 μm, and the coating weight of the first active material layer is 0.2 mg / mm². 2 The compaction density of the first active material layer was 2.0 g / cc, the insulating layer composition (mass ratio) was PVDF:boehmite = 40%:60%, the thickness H of the second region of the insulating layer was 0 μm, and the width W of the insulating layer was 1.2 mm. The insulating layer was not thinned.

[0081] For Examples 1 to 17 and Comparative Examples 1 to 3 described above, processes such as winding cold pressure were performed, the appearance of the electrode sheets was observed, and the energy density was calculated, as shown in Table 1 below.

[0082] [Table 1] JPEG0007897983000002.jpg204170

[0083] Compared to conventional technology, the electrochemical apparatus of the present invention, by providing an adjacent first active material layer and an insulating layer on the electrode sheet, prevents short circuits in the electrochemical apparatus by having the insulating layer cover the burrs on the edges of the first current collector and tab, and by providing a thinly shaved first region on the outside of the insulating layer, the ratio of the thickness of the insulating layer to the thickness of the first active material layer and the shape of the thinning of the insulating layer are controlled, thereby ensuring the safety performance of the electrochemical apparatus, improving the uniformity of force during the roll pressing process of the electrode sheet, and further improving the overall performance of the electrochemical apparatus.

[0084] Specific embodiments of the present application have been described with reference to the drawings mentioned above. However, it will be understood by those skilled in the art that various modifications and substitutions can be made to the specific embodiments of the present application without departing from the spirit and scope of the present application. These modifications and substitutions are limited to the scope of the present application. [Explanation of symbols]

[0085] 1. Electrochemical apparatus 10-pole sheet 11. First current collector 12 Tab 1 13 First active material layer 14. Insulating layer 141 First area 142 Second area 143 Page 1 α acute angle 100 Electronic equipment

Claims

1. It is equipped with an electrode sheet, and the electrode sheet is The first current collector and, A first tab protruding from the first current collector, A first active material layer provided on at least one surface of the first current collector, The first current collector comprises an insulating layer provided along the side edge near the first tab and adjacent to the first active material layer, The insulating layer includes a first region and a second region, the first region being provided on the side closer to the first tab, the second region being provided far from the first tab and adjacent to the first active material layer, and the first region extending from the side of the second region far from the first tab. The thickness of the insulating layer in the first region is smaller than the thickness of the insulating layer in the second region. The weight of the coating of the first active material layer is 0.06 mg / mm ２ ~0.35mg / mm ２ And, The first region includes the first surface, The plane on which the first surface is located intersects with the plane on which the first current collector is located, forming an acute angle α. An electrochemical apparatus characterized in that the thickness of the second region is H, the width of the insulating layer is W, and W / H ≥ cotα.

2. The electrochemical apparatus according to claim 1, characterized in that the range of the acute angle α is 5° to 75°.

3. The electrochemical apparatus according to claim 1, characterized in that the thickness H of the second region is in the range of 20 μm to 100 μm, and the width W of the insulating layer is in the range of 1 mm to 10 mm.

4. The electrochemical apparatus according to claim 1, characterized in that the thickness L of the first active material layer is in the range of 30 μm to 200 μm.

5. comprising an electrode sheet, the electrode sheet is The first current collector and, A first tab protruding from the first current collector, A first active material layer provided on at least one surface of the first current collector, The first current collector comprises an insulating layer provided along the side edge near the first tab and adjacent to the first active material layer, The insulating layer includes a first region and a second region, the first region being provided on the side closer to the first tab, the second region being provided far from the first tab and adjacent to the first active material layer, and the first region extending from the side of the second region far from the first tab. The thickness of the insulating layer in the first region is smaller than the thickness of the insulating layer in the second region. The weight of the coating of the first active material layer is 0.06 mg / mm ２ ~0.35mg / mm ２ And, The electrochemical apparatus is characterized in that the thickness of the second region is H, and the thickness H of the second region and the thickness L of the first active material layer satisfy the relationship 0.3 ≤ H / L ≤ 0.

8.

6. The electrochemical apparatus according to claim 1, characterized in that the compaction density of the first active material layer is 2 g / cc to 6 g / cc.

7. The electrochemical apparatus according to claim 1, characterized in that the insulating layer comprises inorganic particles containing at least one of boehmite, alumina, zirconia, boron oxide, or hexagonal boron nitride, and a binder containing at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, or sodium carboxymethylcellulose.

8. An electronic apparatus characterized by including the electrochemical apparatus described in any one of claims 1 to 7.

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