Liquid injection nozzle, liquid injection device, and method for manufacturing nonaqueous electrolyte secondary battery

Abstract

A liquid injection nozzle (42) according to one embodiment of the present disclosure is for injecting an electrolyte into a nonaqueous electrolyte secondary battery. The material of a tip part (42a) has higher wear resistance than the material of a portion other than the tip part (42a), or is softer than a battery member with which the tip part (42a) comes into contact inside the battery during liquid injection.

Description

Liquid injection nozzle, liquid injection device, and method for manufacturing a non-aqueous electrolyte secondary battery

[0001] The present disclosure relates to a liquid injection nozzle, a liquid injection device, and a method for manufacturing a non-aqueous electrolyte secondary battery, and particularly relates to a liquid injection nozzle, a liquid injection device, and a method for manufacturing a non-aqueous electrolyte secondary battery that are compatible with liquid injection in a state where the inside of the battery is sealed.

[0002] A non-aqueous electrolyte secondary battery including a bottomed cylindrical exterior can, an electrode body and a non-aqueous electrolyte accommodated in the body of the exterior can, and a sealing body closing the opening of the exterior can is known. Also, generally, a liquid electrolyte having a relatively high viscosity is used as the non-aqueous electrolyte. During the manufacture of the secondary battery, the electrolyte is injected into the decompressed secondary battery through a liquid injection nozzle and impregnated into the electrode body.

[0003] Conventionally, various studies have been conducted on the method of injecting the electrolyte from the viewpoint of improving the production efficiency of secondary batteries. For example, Patent Document 1 discloses a technique for reducing the remaining electrolyte in the liquid injection nozzle and suppressing production variations by arranging a flow rate suppressing member having a predetermined protrusion shape inside the liquid injection nozzle.

[0004] Japanese Patent Application Laid-Open No. 2008-91065

[0005] By the way, usually, when injecting the electrolyte into the secondary battery, the tip of the liquid injection nozzle is brought into contact with a battery member inside the secondary battery to stabilize the liquid injection nozzle. However, there is a risk that the tip of the liquid injection nozzle is damaged and the fragments thereof are mixed into the battery. Also, there is a risk that fragments of the battery member damaged by contact with the tip of the liquid injection nozzle are mixed into the battery. Since any of these fragments becomes a foreign matter inside the battery, it is not preferable from the viewpoint of ensuring the safety of the battery. The conventional techniques including the technique described in Patent Document 1 have not considered suppressing the mixing of the above-mentioned fragments and still have room for improvement.

[0006] An object of the present disclosure is to suppress the mixing of foreign matter caused by the liquid injection nozzle into the secondary battery.

[0007] One embodiment of the present disclosure is an electrolyte injection nozzle for injecting electrolyte into the interior of a non-aqueous electrolyte secondary battery, characterized in that the material of the tip portion has higher wear resistance than the material of the other parts, or is softer than the battery components that the tip portion contacts inside the battery during injection.

[0008] An injection device according to one aspect of this disclosure is characterized by comprising the above-described injection nozzle.

[0009] A method for manufacturing a non-aqueous electrolyte secondary battery, according to one aspect of the present disclosure, includes the step of injecting an electrolyte solution into the sealed non-aqueous electrolyte secondary battery through an injection port, characterized in that the material of the tip of the nozzle inserted into the injection port has higher wear resistance than the material of the parts other than the tip of the nozzle, or is softer than the battery components that the tip comes into contact with inside the battery during injection.

[0010] According to one embodiment of the present disclosure, a liquid injection nozzle can suppress the ingress of foreign matter into the secondary battery.

[0011] This is an axial cross-sectional view of a non-aqueous electrolyte secondary battery, which is an example of an embodiment. This is a cross-sectional view showing the vicinity of the sealing body during liquid injection in the secondary battery shown in Figure 1. This is a perspective view of the vicinity of the tip of the liquid injection nozzle, which is an example of an embodiment. This is a figure corresponding to Figure 3 in another example of an embodiment. This is a figure corresponding to Figure 3 in another example of an embodiment. This is a figure corresponding to Figure 3 in another example of an embodiment.

[0012] Hereinafter, an example of an embodiment of a non-aqueous electrolyte secondary battery according to this disclosure will be described in detail with reference to the drawings. The embodiment described below is merely an example, and this disclosure is not limited to the embodiments described below. Furthermore, forms obtained by selectively combining each component of the embodiments described below are included in this disclosure.

[0013] Figure 1 is an axial cross-sectional view of a non-aqueous electrolyte secondary battery 10, which is an example of an embodiment. As shown in Figure 1, the non-aqueous electrolyte secondary battery 10 comprises an electrode body 14, a non-aqueous electrolyte (not shown), and a battery case 15 that houses the electrode body 14 and the non-aqueous electrolyte. The battery case 15 consists of an outer can 16, which is a bottomed cylindrical metal container with one side open in the axial direction, and a sealing body 17 that closes the opening of the outer can 16. Hereinafter, the side of the non-aqueous electrolyte secondary battery 10 with the sealing body 17 in the axial direction (height direction) will be referred to as "up," and the bottom side of the outer can 16 in the axial direction will be referred to as "down."

[0014] The electrode body 14 has a positive electrode 11, a negative electrode 12, and a separator 13, and the positive electrode 11 and the negative electrode 12 are wound in a spiral shape via the separator 13. The positive electrode 11, the negative electrode 12, and the separator 13 are all elongated strips, and are alternately stacked in the radial direction of the electrode body 14 by being wound in a spiral shape. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium deposition. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both the longitudinal and width (short direction). The separator 13 is formed to be at least slightly larger than the positive electrode 11, and two separators are arranged so as to sandwich the positive electrode 11. The non-aqueous electrolyte secondary battery 10 includes insulating plates 18 and 19 arranged above and below the electrode body 14, respectively.

[0015] The positive electrode 11 comprises a positive electrode core and a positive electrode mixture layer formed on the positive electrode core. The positive electrode core can be made of a metal foil that is stable within the potential range of the positive electrode 11, such as aluminum or an aluminum alloy, or a film with the metal arranged on its surface. The positive electrode mixture layer contains a positive electrode active material, a conductive agent, and a binder, and is preferably formed on both sides of the positive electrode core, excluding the exposed portion (not shown) of the positive electrode core to which the positive electrode lead 20 is welded. The positive electrode 11 can be manufactured, for example, by applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, and a binder onto the positive electrode core, drying the coating, and then compressing it to form the positive electrode mixture layer on both sides of the positive electrode core.

[0016] The positive electrode composite layer contains particulate lithium metal composite oxide as the positive electrode active material. The lithium metal composite oxide is a composite oxide containing metal elements such as Co, Mn, Ni, and Al in addition to Li. The metal elements constituting the lithium metal composite oxide are, for example, at least one selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi. Among these, it is preferable to contain at least one selected from Co, Ni, and Mn. Examples of suitable composite oxides include lithium metal composite oxides containing Ni, Co, and Mn, and lithium metal composite oxides containing Ni, Co, and Al.

[0017] Examples of conductive agents included in the positive electrode mixture layer include carbon black such as acetylene black and Ketjenblack, graphite, carbon nanotubes (CNTs), carbon nanofibers, and graphene. Examples of binders included in the positive electrode mixture layer include fluorine-containing resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide, acrylic resins, and polyolefins. In addition, these resins may be used in combination with carboxymethylcellulose (CMC) or its salts, polyethylene oxide (PEO), etc.

[0018] The negative electrode 12 comprises a negative electrode core and a negative electrode mixture layer formed on the negative electrode core. The negative electrode core can be made of a metal foil that is stable within the potential range of the negative electrode 12, such as copper or a copper alloy, or a film with the metal arranged on its surface. The negative electrode mixture layer contains a negative electrode active material, a binder, and optionally a conductive agent, and is preferably formed on both sides of the negative electrode core, excluding the exposed portion (not shown) of the negative electrode core to which the negative electrode lead 21 is welded. The negative electrode 12 can be manufactured by applying a negative electrode mixture slurry containing a negative electrode active material and a binder to the surface of the negative electrode core, drying the coating, and then compressing it to form the negative electrode mixture layer on both sides of the negative electrode core.

[0019] The negative electrode composite layer generally contains a carbon material that reversibly intercepts and releases lithium ions as the negative electrode active material. Suitable examples of carbon materials include natural graphite such as flake graphite, lumpy graphite, and clay-like graphite, as well as artificial graphite such as lumpy artificial graphite and graphitized mesophase carbon microbeads (MCMB). Furthermore, a material containing at least one of elements that alloy with Li, such as Si and Sn, and a material containing such elements may be used as the negative electrode active material. Among these, composite materials containing Si are preferred.

[0020] A preferred example of a composite material containing Si is SiO ２ Examples include materials in which Si nanoparticles are dispersed in a phase or a silicate phase such as lithium silicate, or materials in which Si nanoparticles are dispersed in an amorphous carbon phase. A conductive layer, such as a carbon film, is formed on the particle surface of the composite material.

[0021] The binder in the negative electrode mixture layer may be a fluororesin, PAN, polyimide, acrylic resin, polyolefin, etc., similar to the positive electrode mixture layer, but styrene-butadiene rubber (SBR) is preferred. Furthermore, the negative electrode mixture layer preferably contains CMC or a salt thereof, polyacrylic acid (PAA) or a salt thereof, polyvinyl alcohol (PVA), etc. Among these, a combination of SBR and CMC or a salt thereof, PAA or a salt thereof is preferred. The negative electrode mixture layer may also contain a conductive agent such as CNT.

[0022] A porous sheet having ion permeability and insulating properties is used for the separator 13. Specific examples of porous sheets include microporous thin films, woven fabrics, and nonwoven fabrics. Suitable materials for the separator 13 include polyethylene, polyolefins such as polypropylene, and cellulose. The separator 13 may have a single-layer structure or a multi-layer structure. A heat-resistant resin layer, such as aramid resin, may be formed on the surface of the separator 13. A filler layer containing an inorganic filler may be formed at the interface between the separator 13 and at least one of the positive electrode 11 and the negative electrode 12.

[0023] A positive lead 20 is connected to the positive electrode 11, and a negative lead 21 is connected to the end of the winding of the negative electrode 12. The positive lead 20 extends through a through hole in the insulating plate 18 towards the sealing body 17, and the negative lead 21 extends outside the insulating plate 19 towards the bottom of the outer can 16. The positive lead 20 is connected to the lower surface of the sealing body 17 by welding or the like, so that the sealing body 17 becomes the positive terminal. The negative lead 21 is connected to the inner surface of the bottom of the metal outer can 16 by welding or the like, so that the outer can 16 becomes the negative terminal.

[0024] Non-aqueous electrolytes are lithium-ion conductive. A liquid electrolyte (electrolyte solution) contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixtures of two or more of these. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof. Non-aqueous solvents may also contain halogen-substituted compounds (e.g., fluoroethylene carbonate) in which at least some of the hydrogen atoms in these solvents are replaced with halogen atoms such as fluorine. Examples of electrolyte salts include LiPF4. ６ Lithium salts such as these are used.

[0025] The outer container 16 is cylindrical in shape, with a bottom at one end and an opening at the other end. The body of the outer container 16 houses the electrode body 14 and the non-aqueous electrolyte. Between the body and the opening 24, an annular groove 22 is formed, the diameter of which is smaller than that of the body of the outer container 16.

[0026] The annular groove 22 is a portion of the outer can 16's side surface that is recessed radially inward, and is provided in an annular shape along the circumferential direction of the outer can 16. The annular groove 22 supports the sealing body 17 on its upper surface. The annular groove 22 can be formed, for example, by spinning a portion of the outer can 16's side surface radially inward to create an annular recess radially inward. The width (axial length) of the annular groove 22 is not particularly limited, but for example, it is 0.1 mm or more and 2.0 mm or less. The depth (radial length) of the annular groove 22 is also not particularly limited, but for example, it is 0.5 mm or more and 5.0 mm or less.

[0027] The opening is located on the side of the outer can 16, above the annular groove 22, and forms the opening of the outer can 16. The area near the opening end is bent radially inward, and the sealing body 17 is crimped and fixed to the outer can 16.

[0028] The sealing body 17 is a disc-shaped member equipped with a safety valve. The sealing body 17 is a metal plate having a thick portion 17a to which the positive electrode lead 20 is connected, an outer peripheral portion 17b, and a thin portion 17c that is thinner than the thick portion 17a and the outer peripheral portion 17b. The outer peripheral portion 17b is sandwiched between the open end of the outer can 16 and the annular groove 22 via a gasket 23.

[0029] If an abnormality occurs in the non-aqueous electrolyte secondary battery 10 and the internal pressure rises, the high-temperature gas generated pushes the sealing body 17 upward, causing it to bend at the thin-walled portion 17c and deform so that the thick-walled portion 17a protrudes outward from the battery. This deformation disconnects the connection between the sealing body 17 and the positive electrode lead 20, interrupting the current path in the sealing body 17. If the internal pressure of the non-aqueous electrolyte secondary battery 10 rises further after the current path is interrupted, the thin-walled portion 17c ruptures, forming a gas outlet in the sealing body 17.

[0030] A through-hole 40 for inserting a liquid injection nozzle 42 is formed in the thick-walled portion 17a of the sealing body 17, as will be described later. In a sealed secondary battery 10, this through-hole is sealed by a metal sealing plug 30. The structure of the sealing body 17 is not limited to the structure shown in Figure 1. For example, the through-hole of the sealing body 17 may be formed at any position on the sealing body 17, rather than in the center of the sealing body 17 as shown in Figure 1.

[0031] The gasket 23 is a flexible insulating member that electrically isolates the sealing body 17, which is the positive terminal, from the outer can 16, which is the negative terminal, while ensuring airtightness inside the outer can 16 by being compressed vertically. The material of the gasket 23 is not particularly limited as long as it is a compressible insulating material, and for example, polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), polyamide (PA), etc. can be used.

[0032] Next, the liquid injection nozzle 42 will be described in detail with reference to Figures 2 to 4C. Figure 2 is a cross-sectional view showing the vicinity of the sealing body 17 during liquid injection in the secondary battery 10 shown in Figure 1. Figure 3 is a perspective view of the vicinity of the tip of the liquid injection nozzle 42, which is an example of an embodiment. Figures 4A to 4C are diagrams corresponding to Figure 3 in other examples of the embodiment, respectively.

[0033] An electrolyte injection device is used to inject electrolyte into the secondary battery 10. The electrolyte injection device has an injection chamber for storing electrolyte and an injection nozzle 42 that has a flow path for the electrolyte to flow through it and connects the injection chamber to the inside of the secondary battery 10. The electrolyte is injected into the inside of the secondary battery 10 by inserting the injection nozzle 42 into a through hole 40 formed in the center of the sealing body 17, and after injection, the through hole 40 is sealed by a sealing plug 30 (not shown) to seal the inside of the secondary battery.

[0034] In the example shown in Figure 2, the tip 42a of the liquid injection nozzle 42 presses the positive electrode lead 20 downwards. By bringing the tip into contact with the electrode member inside the battery, the position of the liquid injection nozzle 42 can be stabilized during liquid injection. Note that the electrode member that the tip 42a contacts is not limited to the positive electrode lead 20, but may be, for example, an insulating plate 18 or an electrode body 14.

[0035] The liquid injection device may have a mechanism that brings the liquid injection nozzle 42 into contact with the electrode member at a stress level below a predetermined level. For example, a part of the side surface of the liquid injection nozzle 42 may have a bellows shape. The liquid injection device may also have a control function that adjusts the contact pressure of the liquid injection nozzle.

[0036] In the example shown in Figure 3, the tip of the liquid injection nozzle 42 has a shape in which the tip of the tubular nozzle is cut at an angle. The angle that this cut surface makes with the axial direction of the liquid injection nozzle 42 is, for example, in the range of 15° to 75°. Since such a tip shape of the liquid injection nozzle 42 can be manufactured relatively easily, it is advantageous from the viewpoint of manufacturing cost. As shown in Figure 3, the liquid injection nozzle 42 has an injection port 44 on the rear end side of the tip portion 42a. The injection port 44 is the part in which the electrolyte flows out from the inside of the liquid injection nozzle 42. Because the injection port 44 is on the rear end side of the tip portion 42a, even if the tip portion 42a is in contact with the electrode member, the electrolyte can be injected without the flow being obstructed by the electrode member.

[0037] The material of the tip portion 42a has higher wear resistance than the material of the other parts of the liquid injection nozzle 42, or is softer than the battery components that the tip portion 42a contacts inside the battery during liquid injection. This suppresses the ingress of foreign matter into the secondary battery 10. The thickness (axial length) of the tip portion 42a is, for example, 0.01 mm to 10 mm.

[0038] In this specification, abrasion resistance is evaluated according to the "Abrasion Test Method using Abrasion Wheels" specified in JIS K7204:1999. Furthermore, when comparing the softness of two materials, the material with a larger reciprocal of the hardness value evaluated by the Vickers hardness test is considered softer.

[0039] The material of the parts of the liquid injection nozzle 42 other than the tip 42a is not particularly limited, but for example, it may be resin. Examples of resins used for the parts of the liquid injection nozzle 42 other than the tip 42a include polypropylene (PP), polyphenylene sulfide (PPS), polyamide (PA), polyethylene (PE), vinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and ABS. PP is preferred as the resin used for the parts of the liquid injection nozzle 42 other than the tip 42a. PP has high chemical resistance and does not corrode due to electrolytes.

[0040] The material of the tip portion 42a is, for example, ceramic, nickel, or a nickel alloy. By using ceramic, nickel, or a nickel alloy, which have higher wear resistance than resin, for the tip portion 42a, the ingress of foreign matter into the secondary battery 10 can be suppressed. The tip portion 42a may also be formed by attaching a coating agent containing ceramic particles or nickel or nickel alloy particles. The coating agent may contain, for example, an organic material such as a fluororesin in addition to an inorganic material such as ceramic, nickel, or a nickel alloy. This makes it easy to improve the wear resistance of the tip portion 42a. The ceramic is not particularly limited, but alumina is one example.

[0041] The material of the tip portion 42a may be resin. The resin used for the tip portion 42a should be, for example, softer than the battery components that the tip portion 42a contacts inside the battery during liquid injection. Examples of battery components that the tip portion 42a contacts include metal leads, resin insulating plates, composite layers whose main component is the active material, and metal cores. In the example shown in Figure 1, the battery component that the tip portion 42a contacts is the positive electrode lead 20, but the example is not limited to this. The battery component that is contacted changes depending on the position of the through hole 40, so it can be changed as appropriate. Examples of resins that can be used for the tip portion 42a include polypropylene (PP), polyphenylene sulfide (PPS), polyamide (PA), polyethylene (PE), vinyl chloride (PVC), ABS, polybutylene terephthalate (PBT), polyphenylene ether (PPE), silicone, and fluororesins. Examples of fluororesins include polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). Furthermore, the material of the tip portion 42a may be elastomer.

[0042] The resin used for the tip portion 42a may have higher wear resistance than the resin used for the portions of the liquid injection nozzle 42 other than the tip portion 42a. The combination of the resin used for the tip portion 42a and the resin used for the portions of the liquid injection nozzle 42 other than the tip portion 42a can be appropriately selected from the resins exemplified above. As the resin for the tip portion 42a, it is preferable to use PP and a Teflon (registered trademark) coating using a fluororesin as the resin for the portions of the liquid injection nozzle 42 other than the tip portion 42a. Thereby, while having chemical resistance, the friction at the contact portion can be reduced.

[0043] In addition to FIG. 3, the mode in the vicinity of the tip of the liquid injection nozzle 42 may be, for example, those shown in FIGS. 4A to 4C.

[0044] The liquid injection nozzle 42 shown in FIG. 4A has a protruding portion 46 on the tip side of the liquid injection port 44, and the tip portion 42a is disposed at the tip of the protruding portion 46. Thereby, since the liquid injection nozzle 42 has the liquid injection port 44 on the rear end side of the tip portion 42a, even if the tip portion 42a is in contact with the electrode member, the liquid can be injected without being obstructed by the electrode member from the flow of the electrolytic solution. The protruding portion 46 is, for example, connected to the inner wall of the liquid injection nozzle 42. The axial length of the protruding portion 46 protruding from the liquid injection port 44 is, for example, 1 cm to 10 cm. Since the liquid injection nozzle 42 shown in FIG. 4A injects the liquid while directing the liquid injection port 44 in the axial direction, the electrolytic solution can be injected into the secondary battery 10 at a relatively high speed.

[0045] The liquid injection nozzle 42 shown in FIG. 4B has a liquid injection port 44 on the side surface. Thereby, since the liquid injection nozzle 42 has the liquid injection port 44 on the rear end side of the tip portion 42a, even if the tip portion 42a is in contact with the electrode member, the liquid can be injected without being obstructed by the electrode member from the flow of the electrolytic solution. The size, shape, and number of the liquid injection ports 44 are not particularly limited. Since the area of the liquid injection port 44 is relatively large, the electrolytic solution can be injected into the secondary battery 10 at a relatively high speed.

[0046] The liquid injection nozzle 42 shown in FIG. 4C has a protruding portion 46 with a part of its side surface protruding, and the tip portion 42a is disposed at the tip of the protruding portion 46. Thereby, since the liquid injection nozzle 42 has the liquid injection port 44 on the rear end side rather than the tip portion 42a, even if the tip portion 42a is in contact with the electrode member, the liquid can be injected without being hindered by the electrode member from the flow of the electrolytic solution. The axial length of the protruding portion 46 protruding more than the liquid injection port 44 is, for example, 1 cm to 10 cm. Since the liquid injection nozzle 42 shown in FIG. 4A injects the liquid while directing the liquid injection port 44 in the axial direction, the electrolytic solution can be injected into the secondary battery 10 at a relatively high speed.

[0047] In a cross section perpendicular to the axial direction of the liquid injection nozzle 42, the cross-sectional area of the tip portion 42a may be smaller than the cross-sectional area of the main body portion 42b. In the present specification, the main body portion 42b means a portion on the rear end side of the liquid injection nozzle 42 rather than the liquid injection port 44. The liquid injection nozzles 42 according to FIGS. 3, 4A, and 4C have the above characteristics. Thereby, the area of the tip portion 42a contacting the electrode member can be reduced.

[0048] As described above, the liquid injection nozzle 42 according to the present disclosure has a feature that the material of the tip portion 42a has higher wear resistance than the material of the portion other than the tip portion 42a, or is softer than the battery member that the tip portion 42a contacts inside the battery during liquid injection. Therefore, the mixing of foreign matter caused by the liquid injection nozzle into the secondary battery 10 can be suppressed.

[0049] This disclosure is further illustrated by the following embodiments: Configuration 1: An injection nozzle for injecting an electrolyte into the interior of a non-aqueous electrolyte secondary battery, wherein the material of the tip portion is more wear-resistant than the material of the other parts of the nozzle, or is softer than the battery component that the tip portion contacts inside the battery during injection. Configuration 2: The injection nozzle according to Configuration 1, wherein the injection port is located at the rear end of the tip portion. Configuration 3: The injection nozzle according to Configuration 1 or 2, wherein in a cross section perpendicular to the axial direction, the cross-sectional area of ​​the tip portion is smaller than the cross-sectional area of ​​the main body portion. Configuration 4: An injection device comprising the injection nozzle according to any one of Configurations 1 to 3. Configuration 5: A method for manufacturing a non-aqueous electrolyte secondary battery, comprising the step of injecting an electrolyte into the interior of a sealed non-aqueous electrolyte secondary battery from an injection port, wherein the material of the tip portion of the nozzle inserted into the injection port is more wear-resistant than the material of the other parts of the nozzle, or is softer than the battery component that the tip portion contacts inside the battery during injection.

[0050] 10 Non-aqueous electrolyte secondary battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 15 Battery case, 16 Outer can, 17 Sealing body, 17a Thick-walled section, 17b Outer circumference, 17c Thin-walled section, 18, 19 Insulating plates, 20 Positive electrode lead, 21 Negative electrode lead, 22 Annular groove, 23 Gasket, 30 Sealing plug, 40 Through hole, 42 Liquid injection nozzle, 42a Tip, 44 Liquid injection port, 46 Protruding part

Claims

1. An injection nozzle for injecting electrolyte into the interior of a non-aqueous electrolyte secondary battery, wherein the material of the tip portion has higher wear resistance than the material of the other parts of the nozzle, or is softer than the battery components that the tip portion comes into contact with inside the battery during injection.

2. The liquid injection nozzle according to claim 1, wherein the liquid injection port is located at the rear end of the tip portion.

3. The liquid injection nozzle according to claim 1, wherein, in a cross-section perpendicular to the axial direction, the cross-sectional area of ​​the tip portion is smaller than the cross-sectional area of ​​the main body portion.

4. A liquid injection device comprising a liquid injection nozzle according to any one of claims 1 to 3.

5. A method for manufacturing a non-aqueous electrolyte secondary battery, comprising the step of injecting an electrolyte solution into the inside of a sealed non-aqueous electrolyte secondary battery through an injection port, wherein the material of the tip of a nozzle inserted into the injection port has higher wear resistance than the material of the other parts of the nozzle, or is softer than the battery components that the tip comes into contact with inside the battery during injection.

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