A winding core and cylindrical battery

Abstract

The application discloses a winding core and a cylindrical battery, and relates to the technical field of batteries. The winding core comprises a positive electrode sheet, a negative electrode sheet and a diaphragm, the positive electrode sheet and the negative electrode sheet are separated by the diaphragm, the positive electrode sheet, the negative electrode sheet and the diaphragm are wound to form a winding core with a hollow cylinder structure, the hollow cylinder structure has a center hole, and the winding core is provided with a polymer layer near the inner ring of the center hole; the diameter of the center hole is Φ, the thickness of the polymer layer is D, and the Φ and D satisfy 0.015Φ≤D≤0.15Φ. By coating a layer of porous polymer at the center hole of the winding core, a certain supporting effect can be achieved, gas can be quickly guided and exhausted, and a safety protection effect can be achieved.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and more particularly to a wound core and cylindrical battery. Background Technology

[0002] In pursuit of higher capacity, cylindrical batteries now use higher silicon content. As the number of cycles increases, the expansion and deformation inside the cell becomes more severe, and more gas is produced. As the number of cycles increases, the deformation of the inner ring of the cell can block the central hole. In the event of a safety accident, the gas inside the cell will be blocked and cannot be quickly discharged from the central hole to the pressure relief valve, which may cause serious safety accidents such as cell explosion.

[0003] To prevent the center hole of the battery cell from deforming and becoming blocked during cyclic expansion or safety tests, thus avoiding the smooth discharge of gas and potential safety hazards, a center pin is currently added to the center hole to support the inner electrode plate and prevent blockage caused by deformation. However, the hollow center pin can obstruct the flow of rapidly generated gas into the hollow center. Furthermore, the center pin is made of a hard material, and during impact tests, the center pin can collide violently with the inner electrode plate, potentially causing a short circuit or even an explosion. Utility Model Content

[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a wound core and cylindrical battery. This application involves coating the center hole of the wound core with a porous polymer layer, which provides both structural support and rapid gas flow, thus offering safety protection.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides a wound core, including a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet and the negative electrode sheet are separated by the separator, and the positive electrode sheet, the negative electrode sheet and the separator are wound to form a wound core with a hollow cylindrical structure, wherein the hollow cylindrical structure has a central hole, and a polymer layer is provided on the inner ring of the wound core near the central hole;

[0007] The diameter of the central hole is Φ, and the thickness of the polymer layer is D. Φ and D satisfy: 0.015Φ≤D≤0.15Φ.

[0008] Preferably, D satisfies: 0.1mm≤D≤0.5mm.

[0009] Preferably, the Φ satisfies: 2.5mm≤Φ≤6mm.

[0010] Preferably, the polymer layer is a polyethylene layer, a polytetrafluoroethylene layer, a polyvinylidene fluoride layer, or a polypropylene layer.

[0011] Preferably, the porosity of the polymer layer is 5-70%.

[0012] Preferably, the polymer layer is formed on the inner wall of the central pore by means of: mixing a foaming agent into the polymer or by means of physical or chemical pore-forming agents to form a porous structure.

[0013] Preferably, the surface density of the coating on one side of the positive electrode sheet is 1.3-2.5 g / dm². 2 The compacted density is 3.2-3.6 g / cm³. 3 .

[0014] Preferably, the width of the positive electrode sheet is 35-150mm and the length is 300-4000mm.

[0015] Preferably, the single-sided coating surface density of the negative electrode sheet is 0.6-1.9 g / dm². 2 The compacted density is 1.3-1.8 g / cm³. 3 .

[0016] Preferably, the width of the negative electrode sheet is 35-150mm and the length is 300-4000mm.

[0017] Preferably, the thickness of the diaphragm is 10-25 μm.

[0018] Secondly, this application also provides a cylindrical battery, including the aforementioned winding core.

[0019] Compared with the prior art, the beneficial effects of this application are as follows:

[0020] This application utilizes a porous polymer coating on the central hole wall of the core. This coating not only effectively supports the deformation caused by the expansion of the inner electrode sheets, improving the stability of the core structure, but also prevents the central hole from becoming completely blocked due to severe expansion and deformation. Furthermore, it avoids the possibility of the core exploding in the event of a safety accident due to blockage of the central hole. Additionally, because the polymer has a porous structure, it not only supports the blockage caused by electrode expansion and deformation, allowing gas produced by the core to quickly escape from the holes to the central hole, but also prevents explosions caused by insufficient internal depressurization in the event of a safety issue. Attached Figure Description

[0021] Figure 1 This is a top view of the core described in this application.

[0022] Figure 2 This is an enlarged view of the top view of the core described in this application.

[0023] Figure 3 This is a side view of the core described in this application.

[0024] Figure 1-3 In the middle: 1 is the polymer layer; 2 is the central hole; 3 is the separator; 4 is the negative electrode; 5 is the positive electrode. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0027] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this utility model are commercially available materials, and the components and raw materials used in each parallel experiment are the same.

[0028] Please see Figures 1-2 This utility model provides a wound core, including a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet and the negative electrode sheet are separated by the separator. The positive electrode sheet, the negative electrode sheet and the separator are wound to form a wound core with a hollow cylindrical structure. The hollow cylindrical structure has a central hole. A polymer layer is provided on the inner ring of the wound core near the central hole.

[0029] The diameter of the central hole is Φ, and the thickness of the polymer layer is D. Φ and D satisfy: 0.015Φ≤D≤0.15Φ.

[0030] This application utilizes a porous polymer coating on the central hole wall of the core. This coating not only effectively supports the deformation caused by the expansion of the inner electrode sheets, improving the stability of the core structure, but also prevents the central hole from becoming completely blocked due to severe expansion and deformation. Furthermore, it avoids the possibility of the core exploding in the event of a safety accident due to blockage of the central hole. Additionally, because the polymer has a porous structure, it not only supports the blockage caused by electrode expansion and deformation, allowing gas produced by the core to quickly escape from the holes to the central hole, but also prevents explosions caused by insufficient internal depressurization in the event of a safety issue.

[0031] In one embodiment, D satisfies: 0.1mm≤D≤0.5mm, for example, it can be a range of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any two of these values. In particular, when the thickness of the polymer layer is within this range, it can play a better supporting role, further improve the protective effect, and promote the rapid discharge of air generated by the core from the holes to the center hole.

[0032] In one embodiment, the Φ satisfies: 2.5mm≤Φ≤6mm, for example, it can be a range of 2.5mm, 3mm, 3.5mm, 4.0mm, 4.5mm, 5mm, 5.5mm, 6mm or any two of these values.

[0033] In one embodiment, the polymer layer is a polyethylene layer, a polytetrafluoroethylene layer, a polyvinylidene fluoride layer, or a polypropylene layer.

[0034] In one embodiment, the porosity of the polymer layer is 5-70%, for example, it can be a range of 5%, 6%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 55%, 60%, 65%, 70%, or any two of these values.

[0035] In one embodiment, the single-sided coating density of the positive electrode sheet is 1.3-2.5 g / dm². 2 For example, it could be 1.3g / dm 2 1.4g / dm 2 1.5g / dm 2 1.6g / dm 2 1.7g / dm 2 1.8g / dm 2 1.9g / dm 2 2.0g / dm 2 2.1g / dm 2 2.2g / dm 2 2.3g / dm 2 2.4g / dm 2 2.5g / dm 2 Or a range consisting of any two of these values.

[0036] In one embodiment, the compaction density of the positive electrode sheet is 3.2-3.6 g / cm³. 3 For example, it could be 3.2 g / cm³ 3 3.3g / cm 3 3.4g / cm 3 3.5g / cm3 3.6g / cm 3 Or a range consisting of any two of these values.

[0037] In one embodiment, the width of the positive electrode sheet is 35-150mm, for example, it can be 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or any two of these values.

[0038] In one embodiment, the length of the positive electrode sheet is 300-4000 mm, for example, it can be 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 800 mm, 900 mm, 1000 mm, 1500 mm, 2000 mm, 2500 mm, 3000 mm, 3500 mm, 4000 mm or any two of these values.

[0039] In one embodiment, the single-sided coating areal density of the negative electrode sheet is 0.6-1.9 g / dm². 2 For example, it could be 0.6 g / dm 2 0.7g / dm 2 0.8g / dm 2 0.9g / dm 2 1.0g / dm 2 1.1g / dm 2 1.2g / dm 2 1.3g / dm 2 1.4g / dm 2 1.5g / dm 2 1.6g / dm 2 1.7g / dm 2 1.8g / dm 2 1.9g / dm 2 Or a range consisting of any two of these values.

[0040] In one embodiment, the compaction density of the negative electrode sheet is 1.3-1.8 g / cm³. 3 For example, it could be 1.3g / dm 2 1.4g / dm 2 1.5g / dm 2 1.6g / cm 3 1.7g / cm 3 1.8g / cm 3 Or a range consisting of any two of these values.

[0041] In one embodiment, the width of the negative electrode sheet is 35-150mm, for example, it can be 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or any two of these values.

[0042] In one embodiment, the length of the negative electrode sheet is 300-4000mm, for example, it can be 300mm, 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, 1500mm, 2000mm, 2500mm, 3000mm, 3500mm, 4000mm or any two of these values.

[0043] In one embodiment, the thickness of the diaphragm is 10-25 μm, for example, it can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm or any two of these values.

[0044] In some embodiments, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including a positive active material.

[0045] In some embodiments, the positive electrode active material may be a positive electrode active material known in the art for use in secondary batteries. As a non-limiting example, it may include, but is not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds.

[0046] In some of these embodiments, the type of positive current collector is not particularly limited, and it may be any material known to be suitable for use as a positive current collector.

[0047] In some embodiments, the positive current collector includes metallic materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, as well as carbon materials such as carbon cloth and carbon paper.

[0048] In some embodiments, the positive electrode active material layer also includes a conductive agent and a binder.

[0049] In some embodiments, the negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer comprising a negative active material.

[0050] In this application, there are no particular restrictions on the negative electrode current collector, as long as it can achieve the purpose of this application. For example, it can be copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, or composite current collector, etc.

[0051] In some embodiments, the negative electrode active material includes at least one of graphite, silicon-based materials, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2, and lithium metal.

[0052] In some embodiments, the negative electrode active material layer further includes a conductive agent and a binder.

[0053] In some embodiments, the types of conductive agents mentioned in this application are not limited, and known conductive agents can be used.

[0054] In some embodiments, the conductive agent includes at least one of carbon materials such as acetylene black, needle coke, carbon nanotubes, and graphene.

[0055] In some embodiments, the type of adhesive mentioned in this application is not limited, and known adhesives can be used.

[0056] In some embodiments, the adhesive mentioned includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose, styrene-butadiene rubber, nitrile rubber, fluororubber, isoprene rubber, polybutadiene rubber, ethylene-propylene rubber, styrene-butadiene-styrene block copolymer or its hydrogenation, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene-ethylene copolymer.

[0057] One embodiment of this utility model provides a cylindrical battery, including the aforementioned winding core.

[0058] In some embodiments, the cylindrical battery may include an outer packaging that can be used to encapsulate the aforementioned electrode assembly.

[0059] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0060] In some embodiments, the cylindrical battery can be used as a power source for an electrical device, which may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, digital cameras, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), toys, power tools, energy storage systems, etc.

[0061] Example 1

[0062] This embodiment discloses a winding core, such as... Figure 1 and Figure 2 As shown, the device includes a positive electrode 5, a negative electrode 4, and a separator 3. The positive electrode 5 and the negative electrode 4 are separated by the separator 3. The positive electrode 5, the negative electrode 4, and the separator 3 are wound together to form a core with a hollow cylindrical structure. The separator 3 has a thickness of 16 μm.

[0063] like Figure 2 As shown, the hollow cylindrical structure has a central hole 2 with a diameter of 3 mm. The inner ring of the core near the central hole is coated with a polymer layer 1, which has a thickness of 0.3 mm. The polymer layer is a porous polypropylene layer with a porosity of 40%. The polypropylene can be mixed with a foaming agent to form a porous structure, better supporting the insulation against blockage caused by electrode expansion and deformation. This allows gas produced by the core to be quickly discharged from the holes to the central hole, preventing explosions and other safety accidents caused by insufficient internal pressure relief in the event of a safety issue.

[0064] like Figure 2 As shown, the positive electrode 5 is made of aluminum foil with a single-sided coating surface density of 1.954 g / dm³. 2 The compacted density is 3.458 g / cm³. 3 The width of the positive electrode is 57.8 mm and the length is 699 mm.

[0065] like Figure 2 As shown, the negative electrode sheet is made of copper foil, with a single-sided coating surface density of 1.149 g / dm². 2 The compacted density is 1.665 g / cm³. 3 The width of the negative electrode sheet is 59mm and the length is 7565mm.

[0066] Example 2

[0067] A type of winding core, this embodiment discloses a type of winding core, such as... Figure 1 and Figure 2As shown, the device includes a positive electrode 5, a negative electrode 4, and a separator 3. The positive electrode 5 and the negative electrode 4 are separated by the separator 3. The positive electrode 5, the negative electrode 4, and the separator 3 are wound together to form a core with a hollow cylindrical structure. The separator 3 has a thickness of 15 μm.

[0068] like Figure 2 As shown, the hollow cylindrical structure has a central hole 2 with a diameter of 0.67 mm. A polymer layer 1, 0.1 mm thick, is disposed on the inner ring of the core near the central hole. The polymer layer is a porous polyethylene layer with a porosity of 5%. The polyethylene can be formed into a porous structure by adding a chemical pore-forming agent to better support the clogging caused by the expansion and deformation of the electrode sheet. This allows the gas produced by the core to be quickly discharged from the holes to the central hole, preventing explosions and other safety accidents caused by untimely internal depressurization in the event of a safety problem with the core.

[0069] like Figure 2 As shown, the positive electrode 5 is made of aluminum foil with a single-sided coating surface density of 1.954 g / dm³. 2 The compacted density is 3.458 g / cm³. 3 The width of the positive electrode is 57.8 mm and the length is 699 mm.

[0070] like Figure 2 As shown, the negative electrode sheet is made of copper foil, with a single-sided coating surface density of 1.149 g / dm². 2 The compacted density is 1.665 g / cm³. 3 The width of the negative electrode sheet is 59mm and the length is 7565mm.

[0071] Example 3

[0072] A type of winding core, this embodiment discloses a type of winding core, such as... Figure 1 and Figure 2 As shown, the device includes a positive electrode 5, a negative electrode 4, and a separator 3. The positive electrode 5 and the negative electrode 4 are separated by the separator 3. The positive electrode 5, the negative electrode 4, and the separator 3 are wound together to form a core with a hollow cylindrical structure. The thickness of the separator 3 is 20 μm.

[0073] like Figure 2As shown, the hollow cylindrical structure has a central hole 2 with a diameter of 33 mm. A polymer layer 1, 0.5 mm thick, is disposed on the inner ring of the core near the central hole. The polymer layer is a porous polytetrafluoroethylene (PTFE) layer with a porosity of 70%. The PTFE can be mixed with a foaming agent to form a porous structure, better supporting the insulation against blockage caused by electrode expansion and deformation. This allows gas produced by the core to be quickly discharged from the holes to the central hole, preventing explosions and other safety accidents caused by insufficient internal pressure relief in the event of a safety issue.

[0074] like Figure 2 As shown, the positive electrode 5 is made of aluminum foil with a single-sided coating surface density of 1.954 g / dm³. 2 The compacted density is 3.458 g / cm³. 3 The width of the positive electrode is 57.8 mm and the length is 699 mm.

[0075] like Figure 2 As shown, the negative electrode sheet is made of copper foil, with a single-sided coating surface density of 1.149 g / dm². 2 The compacted density is 1.665 g / cm³. 3 The width of the negative electrode sheet is 59mm and the length is 7565mm.

[0076] In summary, this application, by coating the wall of the central hole of the core with a porous polymer layer, not only effectively supports the deformation caused by the expansion of the inner electrode sheet of the core, improving the stability of the core structure, but also prevents the central hole from being directly blocked due to severe expansion and deformation. Furthermore, it can also prevent the core from exploding in the event of a safety accident due to blockage of the central hole.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A type of winding core, characterized in that, It includes a positive electrode, a negative electrode, and a separator. The positive electrode and the negative electrode are separated by the separator. The positive electrode, the negative electrode, and the separator are wound to form a core with a hollow cylindrical structure. The hollow cylindrical structure has a central hole. A polymer layer is provided on the inner ring of the core near the central hole. The diameter of the central hole is Φ, and the thickness of the polymer layer is D. Φ and D satisfy: 0.015Φ≤D≤0.15Φ.

2. The winding core according to claim 1, characterized in that, The value of D satisfies: 0.1mm≤D≤0.5mm; the value of Φ satisfies: 2.5mm≤Φ≤6mm.

3. The winding core according to claim 1, characterized in that, The polymer layer is a polyethylene layer, a polytetrafluoroethylene layer, a polyvinylidene fluoride layer, or a polypropylene layer.

4. The winding core according to claim 1, characterized in that, The porosity of the polymer layer is 5-70%.

5. The winding core according to claim 1, characterized in that, The areal density of the single-sided coating of the positive electrode sheet is 1.3-2.5 g / dm². 2 The compacted density is 3.2-3.6 g / cm³. 3 .

6. The winding core according to claim 1, characterized in that, The width of the positive electrode sheet is 35-150mm and the length is 300-4000mm.

7. The winding core according to claim 1, characterized in that, The single-sided coating density of the negative electrode sheet is 0.6-1.9 g / dm². 2 The compacted density is 1.3-1.8 g / cm³. 3 .

8. The winding core according to claim 1, characterized in that, The width of the negative electrode sheet is 35-150mm and the length is 300-4000mm.

9. The winding core according to claim 1, characterized in that, The thickness of the diaphragm is 10-25 μm.

10. A cylindrical battery comprising the winding core as described in any one of claims 1-9.

Images