Lithium primary battery

Abstract

The utility model provides a lithium primary battery. The lithium primary battery comprises a positive electrode, a negative electrode, a diaphragm arranged between the positive electrode and the negative electrode, and a non-aqueous electrolyte, a modified layer is arranged on at least one side, facing the negative electrode, of the positive electrode and / or a modified layer is arranged on at least one side of the diaphragm; the modified layer comprises a base material layer and a carbon layer arranged on one side of the base material layer. According to the lithium primary battery, the modified layer with a specific structure is arranged between the positive electrode and the negative electrode, so that the pulse performance of the lithium primary battery at high temperature is further improved, and the internal resistance of the battery is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the battery technical field, specifically relates to a lithium primary battery. BACKGROUND

[0002] Lithium primary batteries are widely used in the fields of portable electronic devices or medical instruments due to their high energy density, wide operating temperature range, long storage life, and strong environmental adaptability. As the demand for electronic device functionality and lightweight continues to increase, the market's demand for the output capacity of lithium primary batteries is also increasing.

[0003] The composition of a lithium primary battery includes a positive electrode (including metal oxides such as manganese dioxide, fluorinated graphite, iron sulfide, or sulfuryl chloride positive active material), a negative electrode of lithium metal or lithium alloy, a separator, and a non-aqueous electrolyte.

[0004] On the one hand, in a lithium primary battery, the negative electrode material is usually lithium metal or lithium alloy, which contains active lithium that is prone to side reactions with certain components in the non-aqueous electrolyte, generating gas or forming a coating film with high resistance (or insulating) components on the negative electrode surface. Therefore, the electrochemical reaction of the lithium primary battery can be impaired, or the internal resistance of the battery increases, causing the discharge performance of the lithium primary battery to deteriorate.

[0005] On the other hand, in a lithium primary battery system with manganese dioxide or fluorinated graphite as the positive active material, a portion of the positive active material dissolves in the non-aqueous electrolyte, generating manganese ions or fluorine ions, which can migrate to the negative electrode side and react with the negative electrode material to form a high-resistance or insulating coating film, thereby increasing the internal resistance of the lithium primary battery and affecting its electrochemical performance.

[0006] In addition, when using manganese dioxide or fluorinated graphite as the positive active material in actual use, the amount of manganese ions or fluorine ions dissolved gradually increases as the depth of discharge increases. If the lithium primary battery is stored at high temperature after discharging to a certain extent, a large amount of high-resistance components can easily form on the negative electrode surface, causing the resistance of the negative electrode and the lithium primary battery to increase significantly. Based on this, when the lithium primary battery is used again after being stored at high temperature, its discharge characteristics decrease significantly, especially the high-temperature large-current discharge characteristics and pulse discharge characteristics decrease significantly, and it cannot perform large-current discharge.

[0007] Therefore, there is an urgent need in the art to develop a lithium primary battery to solve the above problems. SUMMARY

[0008] The utility model discloses in view of the deficiency of prior art, the purpose lies in providing a lithium primary battery, the utility model discloses a modification layer with specific structure is arranged between the positive pole and the negative pole, to further improve the pulse performance of lithium primary battery under high temperature and reduce the internal resistance of battery.

[0009] In order to achieve the purpose of the utility model, the utility model adopts the following technical scheme:

[0010] In the first aspect, the utility model provides a lithium primary battery, the lithium primary battery includes positive pole, negative pole, the diaphragm of setting in the positive pole and the negative pole and non - water electrolyte,

[0011] The positive pole is equipped with modification layer and / or the diaphragm at least one side is equipped with modification layer to the at least one side of negative pole,

[0012] The modification layer includes substrate layer and carbon layer setting in one side of substrate layer.

[0013] The utility model discloses in the positive pole and / or diaphragm at least one side is equipped with modification layer, to protect the negative pole surface from the influence of manganese dioxide or fluorinated graphite positive pole active material, finally avoids the dissolved manganese ion or negative ion and negative pole reaction formation high resistance coating, thereby reduce the internal resistance of lithium primary battery and improve the pulse performance of lithium primary battery, especially not only solve the lithium primary battery when storing after partial discharge, the dissolved ion of positive pole material can migrate to the side of negative pole and cause the technical problem of the increase of battery internal resistance, also solve the poor pulse discharge performance of lithium primary battery under high temperature application environment.

[0014] As the further preferred technical scheme of the utility model, the positive pole is equipped with modification layer to the two sides of negative pole and / or the diaphragm is equipped with modification layer to two sides.

[0015] As the preferred technical scheme of the utility model, when the positive pole at least one side is equipped with modification layer, substrate layer and the at least one surface of positive pole contact, and carbon layer sets up in the side of positive pole to the diaphragm.

[0016] As the preferred technical scheme of the utility model, when the diaphragm at least one side is equipped with modification layer, substrate layer and the at least one surface of diaphragm contact, and carbon layer sets up in the side of diaphragm to the positive pole and / or the side of diaphragm to the negative pole.

[0017] In the utility model, the slurry of carbon layer includes carbon material, binder, thickening agent and dispersing agent. The person skilled in the art can adjust the proportion of each component according to the actual situation, which is not limited.

[0018] In the present application, the carbon material exemplarily includes graphite (such as natural graphite, artificial graphite, etc.), carbon black (such as acetylene black, ketjen black, channel black, furnace black, lump carbon black, thermal cracking carbon black, etc.), carbon fiber or carbon nanotube, or a combination of any one or at least two thereof.

[0019] In the present application, the binder, thickener and dispersant can be any conventional commercially available reagent in the art, and the present application does not limit this.

[0020] In the present application, the dispersant is not particularly limited, as long as it does not react with the carbon material. However, a substance with high volatility or low boiling point is preferred in order to be easily removed.

[0021] As a preferred technical solution of the present application, the length of the carbon layer is 5mm-45mm, for example, it can be 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, etc.; the width is 2mm-35mm, for example, it can be 2mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, etc.

[0022] In the present application, by controlling the length and width of the carbon layer, the carbon material layer can completely adsorb the free fluorine ions, and the length and width that are too small will cause part of the free fluorine ions not to be adsorbed by the carbon material layer, continue to be free to the negative side, thereby causing the internal resistance of the lithium primary battery to increase when stored at high temperature; otherwise, it will cause difficulties in the manufacture of lithium primary batteries, affecting the insulation effect between the positive and negative electrodes.

[0023] As a preferred technical solution of the present application, the thickness of the carbon layer is 0.02mm-0.4mm, for example, it can be 0.02mm, 0.04mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, etc.

[0024] In the present application, by controlling the thickness of the carbon layer, the carbon material layer can completely adsorb the free fluorine ions, and the thickness that is too small will cause part of the free fluorine ions not to be adsorbed by the carbon material layer, continue to be free to the negative side, thereby causing the internal resistance of the lithium primary battery to increase when stored at high temperature, and vice versa, which will reduce the lithium ion conduction rate between the positive and negative electrodes, causing the internal resistance of the lithium primary battery to increase.

[0025] As a further preferred technical scheme of the present application, the length of the carbon layer is 8-40 mm, and the width is 5-28 mm.

[0026] As a further preferred technical scheme of the present application, the thickness of the carbon layer is 0.04-0.3 mm.

[0027] As a preferred technical scheme of the present application, the length of the substrate layer is 7-50 mm, for example, 7 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm, 50 mm, etc.; and the width is 4-40 mm, for example, 4 mm, 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, etc.

[0028] As a preferred technical scheme of the present application, the thickness of the substrate layer is 0.001-0.3 mm, for example, 0.001 mm, 0.005 mm, 0.008 mm, 0.01 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.3 mm, etc.

[0029] As a further preferred technical scheme of the present application, the length of the substrate layer is 10-42 mm, and the width is 7-30 mm.

[0030] As a further preferred technical scheme of the present application, the thickness of the substrate layer is 0.001-0.2 mm.

[0031] As a further preferred technical scheme of the present application, the material of the substrate layer is a fiber material, which exemplarily includes any one or a combination of at least two of non-woven fabric, polyolefin fiber, polyphenylene sulfide fiber, polyester resin fiber (for example, polybutylene terephthalate fiber, etc.), polyamide resin fiber (for example, aromatic polyamide resin fiber, etc.), polyimide fiber, polyimide resin fiber (for example, polyamide-imide fiber, etc.), or polyether ether ketone fiber.

[0032] As a preferred technical scheme of the present application, the area of the carbon layer is 60-100% of the total area of a single side of the positive electrode or the separator, for example, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc.

[0033] As a further preferred technical scheme of the utility model, the area of the carbon layer is 80% to 100% of the total area of one side of the positive electrode or the diaphragm, for example, it can be 80%, 85%, 90%, 95%, 100% and the like.

[0034] In the utility model, through the regulation and control of the area size of the carbon layer, the carbon material layer can completely adsorb the free fluorine ion, and the area is too small to cause part of the free fluorion not to be adsorbed by the carbon material layer, continue to free to the negative side, thereby causing the internal resistance of lithium primary battery to increase when storing at high temperature, and vice versa, which will cause difficulty in the manufacture of lithium primary battery and affect the insulation effect between the positive and negative electrodes.

[0035] As a preferred technical scheme of the utility model, the length of the positive electrode is 8mm to 36mm, for example, it can be 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 36mm and the like; the width is 5mm to 23mm, for example, it can be 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 23mm and the like.

[0036] In the utility model, when the modified layer is arranged on at least one side of the positive electrode, the length of the carbon layer is 5mm to 40mm, and the width is 2mm to 25mm.

[0037] As a preferred technical scheme of the utility model, the length of the diaphragm is 8mm to 40mm, for example, it can be 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 36mm, 38mm, 40mm and the like; the width is 5mm to 30mm, for example, it can be 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 25mm, 28mm, 30mm and the like.

[0038] In the utility model, when the modified layer is arranged on at least one side of the diaphragm, the length of the carbon layer is 5mm to 45mm, and the width is 2mm to 35mm.

[0039] As a preferred technical scheme of the utility model, the lithium primary battery further comprises a cover plate assembly, a positive electrode post and a liquid injection port arranged on the cover plate assembly, a through hole is further arranged on the cover plate assembly, the positive electrode post passes through the through hole and the positive electrode is connected through a first current collecting grid, and the material of the first current collecting grid is an aluminum current collecting grid.

[0040] As a preferred technical scheme of the utility model, the negative electrode is provided with two, and the two negative electrodes are oppositely arranged on the two sides of the positive electrode.

[0041] As the preferred technical scheme of the utility model, the lithium primary battery further comprises a second current collecting grid, the second current collecting grid is connected with two negative electrodes, and the material of the second current collecting grid is a copper current collecting grid.

[0042] In the utility model, the lithium primary battery can be prepared by a conventional preparation method according to actual conditions by the person skilled in the art.

[0043] In the utility model, the modified layer can be prepared by a conventional preparation method according to actual conditions by the person skilled in the art.

[0044] Compared with the prior art, the utility model has the following beneficial effects:

[0045] The utility model provides a kind of lithium primary battery, it is equipped with modified layer at least one side of positive pole and / or diaphragm, to protect negative electrode surface from the influence of manganese dioxide or fluorinated graphite positive active material, finally avoid the manganese ion or negative ion dissolved out and react with negative electrode to form high-resistance coating, so as to reduce the internal resistance of lithium primary battery and improve the pulse performance of lithium primary battery, especially not only solve the technical problem that lithium primary battery is stored after partial discharge, possibly because of the dissolved ion migration of positive electrode material to the side of negative electrode to cause battery internal resistance to rise, simultaneously also solve the technical problem that the pulse discharge performance of lithium primary battery is poor under high temperature application environment. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 For the structure schematic diagram of lithium primary battery provided by the utility model;

[0047] Figure 2 For the schematic diagram of modified layer being arranged on diaphragm surface provided by the utility model;

[0048] Figure 3 For the structure schematic diagram of modified layer being arranged on positive pole and diaphragm surface provided by the utility model and its detail A schematic diagram;

[0049] Figure 4 For the structure schematic diagram of modified layer being arranged on positive pole surface provided by the utility model and its detail B schematic diagram;

[0050] Figure 5 For the schematic diagram of modified layer being arranged on positive pole surface provided by the utility model;

[0051] Figure 6 For the pulse performance diagram of lithium primary battery provided by the utility model in embodiment 1 to embodiment 6 and comparative example 1 under 45 DEG C;

[0052] 1-positive pole, 2-cover plate, 3-glass seal, 4-positive current collector, 5-negative pole, 6-separator, 7-positive pole, 8-modified layer, 81-first modified layer, 82-second modified layer, 9-negative current collector, 10-bottom film, 11-liquid injection port. DETAILED DESCRIPTION

[0053] It should be understood that, in the description of the present application, the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0054] It should be noted that, in the description of the present application, unless otherwise specified and limited, the terms "provided", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0055] The technical solutions of the present application will be further illustrated below in conjunction with the drawings and through specific embodiments.

[0056] Embodiment 1

[0057] The present embodiment provides a lithium primary battery, which comprises a fluorinated graphite positive pole 7, two lithium metal negative poles 5, a polyethylene separator 6 arranged between the fluorinated graphite positive pole 7 and the lithium metal negative pole 5, and a non-aqueous electrolyte, wherein the two lithium metal negative poles 5 are arranged opposite to each other on both sides of the fluorinated graphite positive pole 7. Figure 1 As shown in the figure, the lithium primary battery comprises a fluorinated graphite positive pole 7, two lithium metal negative poles 5, a polyethylene separator 6 arranged between the fluorinated graphite positive pole 7 and the lithium metal negative pole 5, and a non-aqueous electrolyte, wherein the two lithium metal negative poles 5 are arranged opposite to each other on both sides of the fluorinated graphite positive pole 7. Figure 2As shown, the polyethylene separator 6 is provided with a modified layer 8 on the side facing the graphite fluoride positive electrode 7; the modified layer 8 comprises a polyimide substrate layer and a carbon layer provided on one side of the polyimide substrate layer. The polyimide substrate layer is in contact with the surface of the polyethylene separator 6, and the carbon layer is provided on the side of the polyethylene separator 6 facing the graphite fluoride positive electrode 7. The lithium primary battery further comprises a cover plate 2 and a liquid injection port 11 provided on the cover plate 2, the cover plate 2 is provided with a through hole, the glass seal 3 is filled in the through hole, the positive electrode post 1 passes through the through hole and is connected with the graphite fluoride positive electrode 7 through the positive electrode current collector 4, and the two lithium metal negative electrodes 5 are connected with each other through the negative electrode current collector 9. The negative electrode current collector 9 is connected with the bottom of the steel shell by welding, and the bottom film 10 is arranged above the welding position of the negative electrode current collector 9.

[0058] The length of the carbon layer is 24 mm, the width is 21 mm, and the thickness is 0.2 mm; the area of the carbon layer is 100% of the total area of one side of the polyethylene separator 6. The length of the polyimide substrate layer is 26 mm, the width is 22 mm, and the thickness is 0.1 mm.

[0059] The length of the graphite fluoride positive electrode 7 is 22.5 mm, and the width is 20 mm; the length of the polyethylene separator 6 is 24 mm, and the width is 21 mm.

[0060] The composition of the non-aqueous electrolyte includes lithium tetrafluoroborate with a concentration of 1 mol / L and a mixed solvent, which is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0061] The embodiment also provides a preparation method of the lithium primary battery, and the preparation method comprises the following steps:

[0062] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethyl cellulose thickener and methanol dispersant is scraped on one side of the polyimide substrate layer, dried at 120°C, and then cut to obtain the modified layer;

[0063] The modified layer is rolled on one side of the polyethylene separator to be compounded, and the carbon layer is arranged on the side of the polyethylene separator facing the graphite fluoride positive electrode to obtain a preliminary product; and then the preliminary product, the lithium metal negative electrode, the polyethylene separator and the non-aqueous electrolyte are assembled to obtain the lithium primary battery.

[0064] Example 2

[0065] The embodiment provides a lithium primary battery, which comprises a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 arranged between the graphite fluoride positive electrode 7 and the lithium metal negative electrode 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are arranged on the two sides of the graphite fluoride positive electrode 7 respectively; as shown, Figure 3As shown, the polyethylene separator 6 is provided with a first modified layer 81 on the side facing the lithium metal negative electrode 5, and the fluorographite positive electrode 7 is provided with a second modified layer 82 on the side facing the polyethylene separator 6; the first modified layer 81 comprises a first polyimide substrate layer and a first carbon layer provided on one side of the first polyimide substrate layer, and the second modified layer 82 comprises a second polyimide substrate layer and a second carbon layer provided on one side of the second polyimide substrate layer. The first polyimide substrate layer is in contact with the surface of the polyethylene separator 6, the first carbon layer is provided on the side of the polyethylene separator 6 facing the lithium metal negative electrode 5, and the second polyimide substrate layer is provided on the surface of the fluorographite positive electrode 7, and the second carbon layer is provided on the side of the fluorographite positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further comprises a cover plate 2 and a liquid injection port 11 provided on the cover plate 2, the cover plate 2 is provided with a through hole, the glass seal 3 is filled in the through hole, the positive electrode post 1 passes through the through hole and is connected with the fluorographite positive electrode 7 through the positive electrode current collector 4, and the two lithium metal negative electrodes 5 are connected with each other through the negative electrode current collector 9. The negative electrode current collector 9 is connected with the bottom of the steel shell by welding, and the bottom film 10 is arranged above the welding position of the negative electrode current collector 9.

[0066] The length of the first carbon layer provided on the polyethylene separator 6 is 20 mm, the width is 15 mm, and the thickness is 0.1 mm; the area of the first carbon layer is 80% of the total area of the polyethylene separator 6. The length of the first polyimide substrate layer is 22 mm, the width is 15 mm, and the thickness is 0.05 mm. The length of the second carbon layer provided on the fluorographite positive electrode 7 is 20 mm, the width is 12 mm, and the thickness is 0.1 mm; the area of the second carbon layer is 80% of the total area of the fluorographite positive electrode 7. The length of the second polyimide substrate layer is 20 mm, the width is 12 mm, and the thickness is 0.05 mm.

[0067] The length of the fluorographite positive electrode 7 is 20 mm, and the width is 15 mm; the length of the polyethylene separator 6 is 22 mm, and the width is 17 mm.

[0068] The composition of the non-aqueous electrolyte comprises lithium tetrafluoroborate with a concentration of 1 mol / L and a mixed solvent, and the mixed solvent is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0069] The embodiment also provides a preparation method of the lithium primary battery, and the preparation method comprises the following steps:

[0070] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethyl cellulose thickener and methanol dispersant is scraped on one side of the polyimide substrate layer, dried at 120°C, and then cut to obtain the modified layer;

[0071] The first modified layer is rolled onto one side of the polyethylene separator for lamination, and the first carbon layer is disposed on the side of the polyethylene separator facing the lithium metal anode. The second modified layer is rolled onto one side of the fluorinated graphite cathode for lamination, and the second carbon layer is disposed on the side of the fluorinated graphite cathode facing the polyethylene separator, to obtain the initial product. Then, the initial product, the lithium metal anode, the polyethylene separator, and the non-aqueous electrolyte are assembled to obtain a lithium primary battery.

[0072] Example 3

[0073] This embodiment provides a primary lithium battery, comprising a fluorinated graphite positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 disposed between the fluorinated graphite positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are disposed opposite to each other on both sides of the fluorinated graphite positive electrode 7; Figures 4-5 As shown, a modified layer 8 is provided on the side of the fluorinated graphite positive electrode 7 facing the polyethylene separator 6; the modified layer 8 includes a polyimide substrate layer and a carbon layer disposed on one side of the polyimide substrate layer. The polyimide substrate layer is disposed on the surface of the fluorinated graphite positive electrode 7, and the carbon layer is disposed on the side of the fluorinated graphite positive electrode 7 facing the polyethylene separator 6. The lithium primary battery also includes a cover plate 2 and a liquid injection port 11 disposed on the cover plate 2. The cover plate 2 has a through hole, and the glass seal 3 fills the through hole. The positive electrode post 1 passes through the through hole and is connected to the fluorinated graphite positive electrode 7 through the positive electrode current collector 4. The two lithium metal negative electrodes 5 are connected to each other through the negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the bottom film 10 is placed above the welding position of the negative electrode current collector 9.

[0074] The carbon layer has a length of 20 mm, a width of 12 mm, and a thickness of 0.1 mm; the area of ​​the carbon layer is 80% of the total area of ​​the fluorinated graphite cathode 7. The polyimide substrate layer has a length of 22 mm, a width of 12 mm, and a thickness of 0.05 mm.

[0075] The fluorinated graphite cathode 7 has a length of 20 mm and a width of 15 mm; the polyethylene diaphragm 6 has a length of 22 mm and a width of 17 mm.

[0076] The non-aqueous electrolyte consists of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0077] This embodiment also provides a method for preparing the above-mentioned lithium primary battery, the method comprising the following steps:

[0078] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethyl cellulose thickener and methanol dispersant was coated onto one side of a polyimide substrate layer, dried at 120°C and then cut to obtain a modified layer.

[0079] The modified layer is rolled on one side of the fluorinated graphite to be compounded, and the carbon layer is arranged on the side of the fluorinated graphite positive electrode facing the polyethylene separator, to obtain a preliminary product; and then the preliminary product, lithium metal negative electrode, polyethylene separator and non-aqueous electrolyte are assembled to obtain a lithium primary battery.

[0080] Embodiment 4

[0081] The embodiment provides a lithium primary battery, which comprises a fluorinated graphite positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 arranged between the fluorinated graphite positive electrode 7 and the lithium metal negative electrode 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are oppositely arranged on two sides of the fluorinated graphite positive electrode 7; the side of the fluorinated graphite positive electrode 7 facing the polyethylene separator 6 is provided with a modified layer 8; the modified layer 8 comprises a polyimide substrate layer and a carbon layer arranged on one side of the polyimide substrate layer. The polyimide substrate layer is arranged on the surface of the fluorinated graphite positive electrode 7, and the carbon layer is arranged on the side of the fluorinated graphite positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further comprises a cover plate 2 and a liquid injection port 11 arranged on the cover plate 2, the cover plate 2 is provided with a through hole, a glass seal 3 is filled in the through hole, a positive electrode post 1 passes through the through hole and is connected with the fluorinated graphite positive electrode 7 through a positive electrode current collector 4, and the two lithium metal negative electrodes 5 are connected with each other through a negative electrode current collector 9. The negative electrode current collector 9 is connected with the bottom of the steel shell through welding, and a bottom film 10 is arranged above the welding position of the negative electrode current collector 9.

[0082] The length of the carbon layer is 15 mm, the width is 10 mm, and the thickness is 0.25 mm; the area of the carbon layer is 100% of the total area of the fluorinated graphite positive electrode 7. The length of the polyimide substrate layer is 30 mm, the width is 22 mm, and the thickness is 0.15 mm.

[0083] The length of the fluorinated graphite positive electrode 7 is 15 mm, and the width is 10 mm; the length of the polyethylene separator 6 is 17 mm, and the width is 12 mm.

[0084] The composition of the non-aqueous electrolyte comprises lithium tetrafluoroborate with a concentration of 1 mol / L and a mixed solvent, and the mixed solvent is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0085] The embodiment further provides a preparation method of the lithium primary battery, and the preparation method comprises the following steps:

[0086] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethyl cellulose thickening agent and methanol dispersant is scraped on one side of the polyimide substrate layer, dried at 120 DEG C, and then cut to obtain the modified layer;

[0087] The modified layer is rolled on one side of the fluorinated graphite anode to be compounded, and the carbon layer is arranged on the side of the fluorinated graphite anode facing the polyethylene diaphragm to obtain a preliminary product; and then the preliminary product, a lithium metal cathode, a polyethylene diaphragm and a non-aqueous electrolyte are assembled to obtain a lithium primary battery.

[0088] Example 5

[0089] The embodiment provides a lithium primary battery, which comprises a fluorinated graphite anode 7, two lithium metal cathodes 5, a polyethylene diaphragm 6 arranged between the fluorinated graphite anode 7 and the lithium metal cathode 5 and a non-aqueous electrolyte, wherein the two lithium metal cathodes 5 are oppositely arranged on two sides of the fluorinated graphite anode 7; the side of the fluorinated graphite anode 7 facing the polyethylene diaphragm 6 is provided with a modified layer 8; the modified layer 8 comprises a polyimide base material layer and a carbon layer arranged on one side of the polyimide base material layer. The polyimide base material layer is arranged on the surface of the fluorinated graphite anode 7, and the carbon layer is arranged on the side of the fluorinated graphite anode 7 facing the polyethylene diaphragm 6. The lithium primary battery further comprises a cover plate 2 and a liquid injection port 11 arranged on the cover plate 2, the cover plate 2 is provided with a through hole, a glass seal 3 is filled in the through hole, a positive pole 1 passes through the through hole and is connected with the fluorinated graphite anode 7 through a positive current collector 4, and the two lithium metal cathodes 5 are connected with each other through a negative current collector 9. The negative current collector 9 is connected with the bottom of a steel shell through welding, and a bottom film 10 is arranged above the welding position of the negative current collector 9.

[0090] The length of the carbon layer is 6 mm, the width is 4 mm, and the thickness is 0.04 mm; the area of the carbon layer is 60% of the total area of the fluorinated graphite anode 7. The length of the polyimide base material layer is 7 mm, the width is 4 mm, and the thickness is 0.005 mm.

[0091] The length of the fluorinated graphite anode 7 is 8 mm, and the width is 5 mm; the length of the polyethylene diaphragm 6 is 10 mm, and the width is 7 mm.

[0092] The composition of the non-aqueous electrolyte comprises lithium tetrafluoroborate with a concentration of 1 mol / L and a mixed solvent, and the mixed solvent is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0093] The embodiment further provides a preparation method of the lithium primary battery, and the preparation method comprises the following steps:

[0094] A slurry containing graphite, a polyvinylidene fluoride binder, a carboxymethyl cellulose thickening agent and a methanol dispersant is scraped on one side of the polyimide base material layer, dried at 120 DEG C, and then cut to obtain a modified layer;

[0095] The modified layer is rolled on one side of the fluorinated graphite anode to be compounded, and the carbon layer is arranged on the side of the fluorinated graphite anode facing the polyethylene diaphragm to obtain a preliminary product; and then the preliminary product, a lithium metal cathode, a polyethylene diaphragm and a non-aqueous electrolyte are assembled to obtain a lithium primary battery.

[0096] Embodiment 6

[0097] The embodiment provides a lithium primary battery, which comprises a fluorinated graphite anode 7, two lithium metal cathodes 5, a polyethylene diaphragm 6 arranged between the fluorinated graphite anode 7 and the lithium metal cathode 5, and a non-aqueous electrolyte, wherein the two lithium metal cathodes 5 are oppositely arranged on two sides of the fluorinated graphite anode 7; the side of the fluorinated graphite anode 7 facing the polyethylene diaphragm 6 is provided with a modified layer 8; the modified layer 8 comprises a polyimide base material layer and a carbon layer arranged on one side of the polyimide base material layer. The polyimide base material layer is arranged on the surface of the fluorinated graphite anode 7, and the carbon layer is arranged on the side of the fluorinated graphite anode 7 facing the polyethylene diaphragm 6. The lithium primary battery further comprises a cover plate 2 and a liquid injection port 11 arranged on the cover plate 2, the cover plate 2 is provided with a through hole, a glass seal 3 is filled in the through hole, a positive pole 1 passes through the through hole and is connected with the fluorinated graphite anode 7 through a positive current collector 4, and the two lithium metal cathodes 5 are connected with each other through a negative current collector 9. The negative current collector 9 is connected with the bottom of a steel shell through welding, and a bottom film 10 is arranged above the welding position of the negative current collector 9.

[0098] The length of the carbon layer is 36 mm, the width is 23 mm, and the thickness is 0.4 mm; the area of the carbon layer is 100% of the total area of the fluorinated graphite anode 7. The length of the polyimide base material layer is 50 mm, the width is 40 mm, and the thickness is 0.3 mm.

[0099] The length of the fluorinated graphite anode 7 is 36 mm, and the width is 23 mm; the length of the polyethylene diaphragm 6 is 40 mm, and the width is 30 mm.

[0100] The composition of the non-aqueous electrolyte comprises lithium tetrafluoroborate with a concentration of 1 mol / L and a mixed solvent, and the mixed solvent is prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0101] The embodiment further provides a preparation method of the lithium primary battery, and the preparation method comprises the following steps:

[0102] A slurry containing graphite, a polyvinylidene fluoride binder, a carboxymethyl cellulose thickening agent and a methanol dispersant is scraped on one side of the polyimide base material layer, dried at 120 DEG C, and then cut to obtain a modified layer.

[0103] The modified layer is rolled on one side of the fluorinated graphite positive electrode to be compounded, and the carbon layer is arranged on the side of the fluorinated graphite positive electrode facing the polyethylene separator, to obtain a preliminary product; and then the preliminary product, a lithium metal negative electrode, a polyethylene separator and a non-aqueous electrolyte are assembled to obtain the lithium primary battery.

[0104] Comparative Example 1

[0105] The difference between the present comparative example and Example 1 is that no modified layer is arranged, and the others are the same as those in Example 1.

[0106] Test conditions

[0107] The lithium primary batteries provided by Examples 1 to 6 and Comparative Example 1 are tested, and the test method is as follows:

[0108] After discharging 90% of the discharge depth of the electric quantity at a current of 10 mA, the lithium primary batteries are stored at a high temperature of 60℃ for 1 week, and the voltage internal resistance and voltage of the lithium primary batteries before and after storage are tested, and the pulse performance of the lithium primary batteries at a high temperature of 45℃ after storage at a high temperature of 60℃ is tested, and the specific test method is to discharge according to the following pulse mode: 10 mA current constant current discharge for 30 s, and stand by for 1 min.

[0109] The test results are shown in Table 1:

[0110] Table 1

[0111]

[0112]

[0113] As can be seen from Table 1, compared with Comparative Example 1, the lithium primary batteries provided by Examples 1-6 of the present application have a modified layer arranged on at least one side of the positive electrode and / or the separator, which is used to protect the surface of the negative electrode from the influence of manganese dioxide or fluorinated graphite positive active material, thereby avoiding the reaction of dissolved manganese ions or negative ions with the negative electrode to form a high-resistance coating film, thereby reducing the internal resistance of the lithium primary battery at high temperature and improving the pulse performance of the lithium primary battery at high temperature.

[0114] From Figure 6 It can be seen that the lithium primary battery provided by the present application has good pulse discharge performance at high temperature.

[0115] The applicant declares that the process method of the present application is illustrated by the above examples, but the present application is not limited to the above process steps, i.e. it does not mean that the present application must rely on the above process steps to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the raw materials selected by the present application and addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A lithium primary battery, characterized by comprising: The lithium primary battery comprises a positive electrode, a negative electrode, a separator arranged between the positive electrode and the negative electrode, and a non-aqueous electrolyte; At least one side of the positive electrode is provided with a modified layer, and / or at least one side of the separator is provided with a modified layer; The modified layer comprises a substrate layer and a carbon layer arranged on one side of the substrate layer.

2. The lithium primary battery according to claim 1, characterized by When at least one side of the positive electrode is provided with a modified layer, the substrate layer is in contact with at least one surface of the positive electrode, and the carbon layer is arranged on the side of the positive electrode facing the separator; When at least one side of the separator is provided with a modified layer, the substrate layer is in contact with at least one surface of the separator, and the carbon layer is arranged on the side of the separator facing the positive electrode and / or the side of the separator facing the negative electrode.

3. The lithium primary battery according to claim 1 or 2, characterized in that, The length of the carbon layer is 5 mm to 45 mm, and the width is 2 mm to 35 mm; The thickness of the carbon layer is 0.02 mm to 0.4 mm.

4. The lithium primary battery according to claim 3, characterized by The length of the carbon layer is 8 mm to 40 mm, and the width is 5 mm to 28 mm; The thickness of the carbon layer is 0.04 mm to 0.3 mm.

5. The lithium primary battery according to claim 1, characterized by The length of the substrate layer is 7 mm to 50 mm, and the width is 4 mm to 40 mm; The thickness of the substrate layer is 0.001 mm to 0.3 mm; The material of the substrate layer is a fiber material.

6. The lithium primary battery according to claim 5, characterized by The length of the substrate layer is 10 mm to 42 mm, and the width is 7 mm to 30 mm; The thickness of the substrate layer is 0.001 mm to 0.2 mm.

7. The lithium primary battery according to claim 1, characterized by The area of the carbon layer is 60% to 100% of the total area of one side of the positive electrode or the separator.

8. The lithium primary battery according to claim 7, characterized by The area of the carbon layer is 80% to 100% of the total area of one side of the positive electrode or the separator.

9. The lithium primary battery according to claim 1, characterized by The length of the positive electrode is 8 mm to 36 mm, and the width is 5 mm to 23 mm.

10. The lithium primary battery according to claim 1, characterized by The length of the separator is 8 mm to 40 mm, and the width is 5 mm to 30 mm.

11. The lithium primary battery according to claim 1, characterized by The lithium primary battery further comprises a cover plate assembly, a positive electrode post and a liquid injection port arranged on the cover plate assembly, and the cover plate assembly is further provided with a through hole, the positive electrode post passes through the through hole and the positive electrode is connected through a first current collector.

12. The lithium primary battery according to claim 1, characterized by The negative electrode is provided with two, and the two negative electrodes are oppositely arranged on both sides of the positive electrode. The lithium primary battery further comprises a second current collector, and the second current collector connects the two negative electrodes.

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