Lithium primary battery

Abstract

This application provides a lithium primary battery. The lithium primary battery comprises a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein a modified layer is provided on at least one side of the positive electrode facing the negative electrode and / or a modified layer is provided on at least one side of the separator, and the modified layer comprises a base layer and a carbon layer provided on one side of the base layer. This application further improves the pulse performance of the lithium primary battery at high temperatures and reduces the internal resistance of the battery by providing a modified layer having a specific structure between the positive electrode and the negative electrode.

Description

Technical Field

[0001] This application claims priority to a Chinese patent application with application number 202422873865.0 filed with the Chinese Patent Office on November 22, 2024, and incorporates all the contents of the above application by reference.

[0002] This application relates to the technical field of batteries, specifically to primary lithium batteries.

Background Art

[0003] Primary lithium batteries have advantages such as high energy density, wide operating temperature range, long storage life, and strong environmental adaptability, so they are widely applied in fields such as portable electronic devices or medical devices. With the increasing needs for the functionality and weight reduction of electronic devices, the market's requirements for the output capacity of primary lithium batteries are also becoming increasingly high.

[0004] The structure of a primary lithium battery includes a positive electrode (including a positive electrode active material such as metal oxides like manganese dioxide, graphite fluoride, iron sulfide or thionyl chloride), a negative electrode of lithium metal or lithium alloy, a separator, and a non-aqueous electrolyte.

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, in a primary lithium battery, the negative electrode material is usually lithium metal or lithium alloy, and the active lithium contained therein is likely to cause side reactions with certain components in the non-aqueous electrolyte to generate gas or form a coating film with high resistance (or insulating) components on the surface of the negative electrode. Therefore, the electrochemical reaction of the primary lithium battery may be impaired, and the resistance inside the battery may increase accordingly, which may lead to the deterioration of the discharge performance of the primary lithium battery. [[ID=३२]]

[0006] On the other hand, in lithium primary battery systems using manganese dioxide or graphite fluoride as the positive electrode active material, some of the positive electrode active material may dissolve in the non-aqueous electrolyte, generating manganese ions or fluoride ions. These released ions may then migrate to the negative electrode side and react with the negative electrode material to form a high-resistance or insulating coating, potentially increasing the internal resistance of the lithium primary battery and affecting its electrochemical performance.

[0007] Furthermore, when manganese dioxide or graphite fluoride is actually used as the positive electrode active material, the amount of manganese ions or fluoride ions eluted gradually increases with increasing depth of discharge. When a lithium primary battery is stored under high-temperature conditions after being discharged to a certain extent, a large amount of high-resistance components tend to form on the surface of the negative electrode, and the resistance of the negative electrode and the lithium primary battery increases significantly. Based on this, when a lithium primary battery is reused after being stored at high temperatures, some electrical energy remains in the lithium primary battery, but its discharge characteristics deteriorate significantly. In particular, its ability to perform high-current discharge and pulsed discharge at high temperatures deteriorates considerably, making it impossible to perform high-current discharge.

[0008] Therefore, in this field, the development of lithium primary batteries to address the above-mentioned shortcomings is urgently needed. [Means for solving the problem]

[0009] This invention provides a lithium primary battery. This invention further improves the pulse performance of a lithium primary battery at high temperatures and reduces the internal resistance of the battery by providing a modified layer with a specific structure between the positive electrode and the negative electrode.

[0010] This application is, The electrolyte comprises a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and a non-aqueous electrolyte. A modified layer is provided on at least one side of the positive electrode facing the negative electrode, and / or a modified layer is provided on at least one side of the separator. The modified layer includes a base layer and a carbon layer provided on one side of the base layer. We provide lithium primary batteries. [Effects of the Invention]

[0011] With respect to related technologies, this application offers the following beneficial effects.

[0012] This invention provides a lithium primary battery that protects the surface of the negative electrode from the influence of manganese dioxide or graphite fluoride positive electrode active material by providing a modified layer on at least one side of the positive electrode and / or separator. Ultimately, it prevents eluted manganese ions or negative ions from reacting with the negative electrode to form a high-resistance coating, thereby reducing the internal resistance of the lithium primary battery and improving its pulse performance. In particular, it solves the technical problem that when a lithium primary battery is partially discharged and then stored, eluted ions from the positive electrode material can move to the negative electrode side, potentially causing an increase in the battery's internal resistance. At the same time, it also solves the technical problem of poor pulse discharge performance of lithium primary batteries in high-temperature application environments.

[0013] After reviewing and understanding the drawings and detailed descriptions, other embodiments can also be understood. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of the structure of the lithium primary battery relating to the present invention. [Figure 2] This is a schematic diagram showing that the modified layer relating to the present invention is provided on the surface of the separator. [Figure 3] This is a schematic diagram of the structure in which the modified layer relating to the present application is provided on the surfaces of the positive electrode and the separator, and a schematic diagram of its details A. [Figure 4] This is a schematic diagram of the structure in which the modified layer relating to the present invention is provided on the surface of the positive electrode, and a schematic diagram of its details B. [Figure 5] This is a schematic diagram showing that the modified layer relating to the present invention is provided on the surface of the positive electrode. [Figure 6] This figure shows the pulse performance at 45°C of lithium primary batteries according to Examples 1 to 6 and Comparative Example 1 of this application.

Description of Symbols

[0015] 1 Positive electrode terminal 2 Cover plate 3 Glass seal 4 Positive current collector 5 Negative electrode 6 Separator 7 Positive electrode 8 Modified layer 81 First modified layer 82 Second modified layer 9 Negative current collector 10 Base film 11 Liquid injection port

Embodiments for Carrying out the Invention

[0016] This application provides a primary lithium battery, which includes a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and a non-aqueous electrolyte.

[0017] A modified layer is provided on at least one side of the positive electrode facing the negative electrode and / or on at least one side of the separator.

[0018] The modified layer includes a base material layer and a carbon layer provided on one side of the base material layer.

[0019] By providing a modified layer on at least one side of the positive electrode and / or the separator, this application protects the surface of the negative electrode from the influence of the positive electrode active materials such as manganese dioxide or graphite fluoride, and ultimately avoids the eluted manganese ions or negative ions reacting with the negative electrode to form a high-resistance coating film, reduces the internal resistance of the primary lithium battery, improves the pulse performance of the primary lithium battery. In particular, when the primary lithium battery is stored after being partially discharged, it not only solves the technical problem that the eluted ions of the positive electrode material may cause an increase in the internal resistance of the battery by moving to the negative electrode side, but also solves the technical problem that the pulse discharge performance of the primary lithium battery in a high-temperature application environment is poor.

[0020] A preferred technical arrangement of the present invention is that modified layers are provided on both sides of the positive electrode toward the negative electrode, and / or modified layers are provided on both sides of the separator.

[0021] In a preferred technical configuration of the present invention, when a modified layer is provided on at least one side of the positive electrode, the substrate layer is in contact with at least one surface of the positive electrode, and the carbon layer is provided on the side of the positive electrode facing the separator.

[0022] In a preferred technical arrangement of the present invention, a modified layer is provided on at least one side of the separator, wherein the substrate layer is in contact with at least one surface of the separator, and the carbon layer is provided on the side of the separator facing the positive electrode and / or the side of the separator facing the negative electrode.

[0023] In this application, the carbon layer slurry comprises a carbon material, a binder, a thickener, and a dispersant. Those skilled in the art can adjust the proportions of each component according to the actual circumstances, and are not limited thereto.

[0024] In this application, the carbon material includes, as an example, one or at least two of the following: graphite (e.g., natural graphite, artificial graphite, etc.), carbon black (e.g., acetylene black, Ketjen black, channel black, furnace black, block black, thermal black, etc.), carbon fibers, or carbon nanotubes.

[0025] In this application, the binder, thickener, and dispersant may be any commercially available reagents commonly used in the art, and this application is not limited thereto.

[0026] In this application, the dispersant is not particularly limited and should be one that does not react with the carbon material. However, a substance with high volatility or a low boiling point can be selected to facilitate removal.

[0027] In the present invention, a preferred technical arrangement is that the length of the carbon layer is 5 mm to 45 mm, for example, 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, 42 mm, 45 mm, etc., and the width is 2 mm to 35 mm, for example, 2 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, etc.

[0028] In this invention, by adjusting and controlling the length and width of the carbon layer, the carbon material layer can completely adsorb free fluoride ions. If the length and width are too small, some free fluoride ions will not be adsorbed by the carbon material layer and will continue to be released to the negative electrode side, causing an increase in the internal resistance of the lithium primary battery during high-temperature storage. Conversely, this can make the manufacture of the lithium primary battery difficult and affect the insulating effect between the positive and negative electrodes.

[0029] In the present invention, a preferred technical solution is to have a carbon layer thickness of 0.02 mm to 0.4 mm, for example, 0.02 mm, 0.04 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, 0.32 mm, 0.35 mm, 0.38 mm, 0.4 mm, etc.

[0030] In this invention, by adjusting and controlling the thickness of the carbon layer, the carbon material layer can completely adsorb free fluoride ions. If the thickness is too small, some free fluoride ions will not be adsorbed by the carbon material layer and will continue to be released to the negative electrode side, causing an increase in the internal resistance of the lithium primary battery when stored at high temperatures. Conversely, this reduces the conduction rate of lithium ions between the positive and negative electrodes, increasing the internal resistance of the lithium primary battery.

[0031] In the present invention, a preferred technical configuration is one in which the length of the carbon layer is 8 to 40 mm and the width is 5 to 28 mm.

[0032] In the present invention, a preferred technical configuration is one in which the thickness of the carbon layer is 0.04 to 0.3 mm.

[0033] In the present invention, a preferred technical arrangement is that the length of the base layer is 7 mm to 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 mm to 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.

[0034] In the present invention, a preferred technical arrangement is that the thickness of the base material layer is 0.001 mm to 0.3 mm, and may be, 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.

[0035] In the present invention, a preferred technical configuration is one in which the length of the base layer is 10 mm to 42 mm and the width is 7 mm to 30 mm.

[0036] In the present invention, a preferred technical configuration is one in which the thickness of the base material layer is 0.001 mm to 0.2 mm.

[0037] In a preferred technical application of the present invention, the material of the base layer is a fibrous material, which, as an example, includes one or at least two of the following: nonwoven fabric, polyolefin fiber, polyphenylene sulfide fiber, polyester resin fiber (e.g., polybutylene terephthalate fiber, etc.), polyamide resin fiber (e.g., aromatic polyamide resin fiber, etc.), polyimide fiber, polyimide resin fiber (e.g., polyamide-imide fiber, etc.), or polyetheretherketone fiber.

[0038] In the present invention, a preferred technical solution is that the area of ​​the carbon layer is 60% to 100% of the total area of ​​one side of the positive electrode or the separator, and may be, for example, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc.

[0039] In the present invention, a preferred technical solution is that the area of ​​the carbon layer is 80% to 100% of the total area of ​​one side of the positive electrode or the separator, and may be, for example, 80%, 85%, 90%, 95%, 100%, etc.

[0040] In this invention, by adjusting and controlling the area of ​​the carbon layer, the carbon material layer can completely adsorb free fluoride ions. If the area is too small, some free fluoride ions will not be adsorbed by the carbon material layer and will continue to be released to the negative electrode side, causing an increase in the internal resistance of the lithium primary battery during high-temperature storage. Conversely, this can make the manufacture of the lithium primary battery difficult and affect the insulating effect between the positive and negative electrodes.

[0041] In the present invention, a preferred technical arrangement is that the length of the positive electrode is 8 mm to 36 mm, for example, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 36 mm, etc., and the width is 5 mm to 23 mm, for example, 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 23 mm, etc.

[0042] In this application, when the modified layer is provided on at least one side of the positive electrode, the length of the carbon layer is 5 mm to 40 mm and the width is 2 mm to 25 mm.

[0043] In the present invention, a preferred technical arrangement is that the length of the separator is 8 mm to 40 mm, for example, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 36 mm, 38 mm, 40 mm, etc., and the width is 5 mm to 30 mm, for example, 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 25 mm, 28 mm, 30 mm, etc.

[0044] In this application, when the modified layer is provided on at least one side of the separator, the length of the carbon layer is 5 mm to 45 mm and the width is 2 mm to 35 mm.

[0045] In a preferred technical configuration of the present invention, the lithium primary battery further includes a cover plate assembly, a positive electrode post provided on the cover plate assembly, and a liquid filling port, wherein the cover plate assembly is further provided with a through hole, the positive electrode post is connected to the positive electrode via a first current collector network through the through hole, and the material of the first current collector network is an aluminum current collector network.

[0046] In a preferred technical arrangement of the present invention, two negative electrodes are provided, and the two negative electrodes are provided facing each other on both sides of the positive electrode.

[0047] In a preferred technical configuration of the present invention, the lithium primary battery further includes a second current collector network connecting the two negative electrodes, wherein the material of the second current collector network is a copper current collector network.

[0048] In this application, the lithium primary battery can be manufactured by a person skilled in the art using a conventional manufacturing method, depending on the actual circumstances.

[0049] In this application, the modified layer can be manufactured by a person skilled in the art using a conventional manufacturing method, depending on the actual circumstances.

[0050] Furthermore, in the description of this application, directions or positional relationships indicated by terms such as "center," "vertical direction," "horizontal direction," "up," "down," "front," "back," "left," "right," "perpendicular," "horizontal," "top," "bottom," "inside," and "outside" are based on the directions or positional relationships shown in the drawings and are merely for the purpose of simplifying and streamlining the description of this application. They do not indicate or imply that the device or element being referred to necessarily has a specific direction or must be constructed and operated in a specific direction, and therefore should not be understood as limiting this application. In the description of this application, unless otherwise specified, "multiple" means two or more.

[0051] In this description, unless otherwise specified or limited, terms such as "attachment," "connection," "linking," and "fixing" should be interpreted broadly. For example, a fixed connection may be a detachable connection, an integrally molded connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. A person skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific case.

[0052] The technical proposal of this application will be described below with reference to the drawings and specific embodiments.

[0053] Example 1 This embodiment provides a lithium primary battery, as shown in Figure 1, comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, where the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and as shown in Figure 2, a modified layer 8 is provided on the side of the polyethylene separator 6 facing the graphite fluoride positive electrode 7, and 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 includes a cover plate 2 and an injection port 11 provided in the cover plate 2. The cover plate 2 has a through hole, a glass seal 3 is filled into the through hole, the positive electrode column 1 is connected to the graphite fluoride positive electrode 7 via a positive electrode current collector 4 through the through hole, and the two lithium metal negative electrodes 5 are connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the undercoat 10 is located above the welding position of the negative electrode current collector 9.

[0054] Here, the carbon layer had a length of 24 mm, a width of 21 mm, and a thickness of 0.2 mm, and the area of ​​the carbon layer was 100% of the total area of ​​one side of the polyethylene separator 6. The polyimide substrate layer had a length of 26 mm, a width of 22 mm, and a thickness of 0.1 mm.

[0055] The length of the graphite fluoride positive electrode 7 was 22.5 mm and its width was 20 mm, while the length of the polyethylene separator 6 was 24 mm and its width was 21 mm.

[0056] The non-aqueous electrolyte consisted of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which was prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0057] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0058] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0059] The modified layer was roll-pressed and composited onto one side of the polyethylene separator, and the carbon layer was placed on the side of the polyethylene separator facing the graphite fluoride cathode to obtain the initial product. Subsequently, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0060] Example 2 This embodiment provides a lithium primary battery comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and as shown in Figure 3, a first modified layer 81 is provided on the side of the polyethylene separator 6 facing the lithium metal negative electrode 5, and a second modified layer 82 is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6, wherein 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 was in contact with the surface of the polyethylene separator 6, the first carbon layer was provided on the side of the polyethylene separator 6 facing the lithium metal negative electrode 5, and the second polyimide substrate layer was provided on the surface of the fluoride graphite positive electrode 7, the second carbon layer was provided on the side of the fluoride graphite positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further included a cover plate 2 and an injection port 11 provided on the cover plate 2, with a through hole provided in the cover plate 2, a glass seal 3 filled into the through hole, the positive electrode column 1 passing through the through hole and connected to the fluoride graphite positive electrode 7 via a positive electrode current collector 4, and the two lithium metal negative electrodes 5 were connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 was connected to the bottom of the steel shell by welding, and the undercoat 10 was located above the welding position of the negative electrode current collector 9.

[0061] Here, the length of the first carbon layer provided in the polyethylene separator 6 was 20 mm, the width was 15 mm, and the thickness was 0.1 mm, and the area of ​​the first carbon layer was 80% of the total area of ​​the polyethylene separator 6. The length of the first polyimide substrate layer was 22 mm, the width was 15 mm, and the thickness was 0.05 mm. The length of the second carbon layer provided in the fluoride graphite cathode 7 was 20 mm, the width was 12 mm, and the thickness was 0.1 mm, and the area of ​​the second carbon layer was 80% of the total area of ​​the fluoride graphite cathode 7. The length of the second polyimide substrate layer was 20 mm, the width was 12 mm, and the thickness was 0.05 mm.

[0062] The length of the graphite fluoride positive electrode 7 was 20 mm and its width was 15 mm, while the length of the polyethylene separator 6 was 22 mm and its width was 17 mm.

[0063] The non-aqueous electrolyte consisted of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which was prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0064] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0065] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0066] The first modified layer was roll-pressed and compounded onto one side of the polyethylene separator, and the first carbon layer was provided on the side of the polyethylene separator facing the lithium metal anode. The second modified layer was roll-pressed and compounded onto one side of the fluoride graphite cathode, and the second carbon layer was provided on the side of the fluoride graphite cathode facing the polyethylene separator. An initial product was obtained, and thereafter, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0067] Example 3 This embodiment provides a lithium primary battery comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, where the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and as shown in Figures 4 and 5, a modified layer 8 is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6, and 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 provided on the surface of the graphite fluoride positive electrode 7, and the carbon layer is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further includes a cover plate 2 and an injection port 11 provided in the cover plate 2. The cover plate 2 has a through hole, a glass seal 3 is filled into the through hole, the positive electrode column 1 is connected to the graphite fluoride positive electrode 7 via a positive electrode current collector 4 through the through hole, and the two lithium metal negative electrodes 5 are connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the undercoat 10 is located above the welding position of the negative electrode current collector 9.

[0068] Here, the carbon layer had a length of 20 mm, a width of 12 mm, and a thickness of 0.1 mm, and the area of ​​the carbon layer was 80% of the total area of ​​the fluoride graphite cathode 7. The polyimide substrate layer had a length of 22 mm, a width of 12 mm, and a thickness of 0.05 mm.

[0069] The length of the graphite fluoride positive electrode 7 was 20 mm and its width was 15 mm, while the length of the polyethylene separator 6 was 22 mm and its width was 17 mm.

[0070] The non-aqueous electrolyte consisted of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which was prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0071] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0072] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0073] The modified layer was roll-pressed and compounded with the fluorinated graphite on one side, and the carbon layer was placed on the side of the fluorinated graphite cathode facing the polyethylene separator to obtain the initial product. Subsequently, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0074] Example 4 This embodiment provides a lithium primary battery comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and a modified layer 8 is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6, and 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 provided on the surface of the graphite fluoride positive electrode 7, and the carbon layer is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further includes a cover plate 2 and an injection port 11 provided in the cover plate 2. The cover plate 2 has a through hole, a glass seal 3 is filled into the through hole, the positive electrode column 1 is connected to the graphite fluoride positive electrode 7 via a positive electrode current collector 4 through the through hole, and the two lithium metal negative electrodes 5 are connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the undercoat 10 is located above the welding position of the negative electrode current collector 9.

[0075] Here, the carbon layer had a length of 15 mm, a width of 10 mm, and a thickness of 0.25 mm, and the area of ​​the carbon layer was 100% of the total area of ​​the fluoride graphite cathode 7. The polyimide substrate layer had a length of 30 mm, a width of 22 mm, and a thickness of 0.15 mm.

[0076] The length of the graphite fluoride positive electrode 7 was 15 mm and its width was 10 mm, while the length of the polyethylene separator 6 was 17 mm and its width was 12 mm.

[0077] The non-aqueous electrolyte consisted of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which was prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0078] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0079] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0080] The modified layer was roll-pressed and composited onto one side of the graphite fluoride cathode, and the carbon layer was placed on the side of the graphite fluoride cathode facing the polyethylene separator to obtain the initial product. Subsequently, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0081] Example 5 This embodiment provides a lithium primary battery comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and a modified layer 8 is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6, and 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 provided on the surface of the graphite fluoride positive electrode 7, and the carbon layer is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further includes a cover plate 2 and an injection port 11 provided in the cover plate 2. The cover plate 2 has a through hole, a glass seal 3 is filled into the through hole, the positive electrode column 1 is connected to the graphite fluoride positive electrode 7 via a positive electrode current collector 4 through the through hole, and the two lithium metal negative electrodes 5 are connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the undercoat 10 is located above the welding position of the negative electrode current collector 9.

[0082] Here, the carbon layer had a length of 6 mm, a width of 4 mm, and a thickness of 0.04 mm, and the area of ​​the carbon layer was 60% of the total area of ​​the fluoride graphite cathode 7. The polyimide substrate layer had a length of 7 mm, a width of 4 mm, and a thickness of 0.005 mm.

[0083] The length of the graphite fluoride positive electrode 7 was 8 mm and its width was 5 mm, while the length of the polyethylene separator 6 was 10 mm and its width was 7 mm.

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

[0085] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0086] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0087] The modified layer was roll-pressed and composited onto one side of the graphite fluoride cathode, and the carbon layer was placed on the side of the graphite fluoride cathode facing the polyethylene separator to obtain the initial product. Subsequently, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0088] Example 6 This embodiment provides a lithium primary battery comprising a graphite fluoride positive electrode 7, two lithium metal negative electrodes 5, a polyethylene separator 6 provided between the graphite fluoride positive electrode 7 and the lithium metal negative electrodes 5, and a non-aqueous electrolyte, wherein the two lithium metal negative electrodes 5 are provided opposite each other on both sides of the graphite fluoride positive electrode 7, and a modified layer 8 is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6, and 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 provided on the surface of the graphite fluoride positive electrode 7, and the carbon layer is provided on the side of the graphite fluoride positive electrode 7 facing the polyethylene separator 6. The lithium primary battery further includes a cover plate 2 and an injection port 11 provided in the cover plate 2. The cover plate 2 has a through hole, a glass seal 3 is filled into the through hole, the positive electrode column 1 is connected to the graphite fluoride positive electrode 7 via a positive electrode current collector 4 through the through hole, and the two lithium metal negative electrodes 5 are connected to each other via a negative electrode current collector 9. The negative electrode current collector 9 is connected to the bottom of the steel shell by welding, and the undercoat 10 is located above the welding position of the negative electrode current collector 9.

[0089] Here, the carbon layer had a length of 36 mm, a width of 23 mm, and a thickness of 0.4 mm, and the area of ​​the carbon layer was 100% of the total area of ​​the fluoride graphite cathode 7. The polyimide substrate layer had a length of 50 mm, a width of 40 mm, and a thickness of 0.3 mm.

[0090] The length of the graphite fluoride positive electrode 7 was 36 mm and its width was 23 mm, while the length of the polyethylene separator 6 was 40 mm and its width was 30 mm.

[0091] The non-aqueous electrolyte consisted of lithium tetrafluoroborate at a concentration of 1 mol / L and a mixed solvent, which was prepared by mixing propylene carbonate (PC) and 1,2-dimethoxyethane (DME) in a volume ratio of 1:1.

[0092] This embodiment further provides a method for manufacturing the lithium primary battery described above, the manufacturing method comprising the following steps.

[0093] A slurry containing graphite, polyvinylidene fluoride binder, carboxymethylcellulose thickener, and methanol dispersant was squeegeeed onto one side of a polyimide substrate layer, dried at 120°C, and then cut to obtain a modified layer.

[0094] The modified layer was roll-pressed and composited onto one side of the graphite fluoride cathode, and the carbon layer was placed on the side of the graphite fluoride cathode facing the polyethylene separator to obtain the initial product. Subsequently, the initial product, lithium metal anode, polyethylene separator, and non-aqueous electrolyte were assembled to obtain a lithium primary battery.

[0095] Comparative Example 1 The only difference between this comparative example and Example 1 was the absence of a modified layer; otherwise, it was the same as Example 1.

[0096] Test conditions The lithium primary batteries according to Examples 1 to 6 and Comparative Example 1 were tested, and the test method was as follows.

[0097] After discharging 90% of the energy with a current of 10mA, the lithium primary battery was stored at a high temperature of 60°C for one week. The voltage, internal resistance, and voltage of the lithium primary battery before and after storage, as well as the pulse performance of the lithium primary battery at a high temperature of 45°C after storage at 60°C, were tested. Specifically, the following pulse mode was used for discharge: constant current discharge at 10mA for 30s, followed by 1min of standing time.

[0098] The test results are shown in Table 1.

[0099] [Table 1]

[0100] Table 1 shows that, compared to Comparative Example 1, the lithium primary batteries according to Examples 1 to 6 of the present application protect the surface of the negative electrode from the influence of manganese dioxide or graphite fluoride positive electrode active material by providing a modified layer on at least one side of the positive electrode and / or separator. Ultimately, this prevents the eluted manganese ions or negative ions from reacting with the negative electrode to form a high-resistance coating, thereby reducing the internal resistance of the lithium primary battery at high temperatures and improving the pulse performance of the lithium primary battery at high temperatures.

[0101] Figure 6 shows that the lithium primary battery according to the present invention has good pulse discharge performance at high temperatures.

Claims

1. The electrolyte comprises a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and a non-aqueous electrolyte. A modified layer is provided on at least one side of the positive electrode facing the negative electrode, and / or a modified layer is provided on at least one side of the separator. The modified layer includes a base layer and a carbon layer provided on one side of the base layer. Lithium primary battery.

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

3. 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. A lithium primary battery according to claim 1 or 2.

4. 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. The lithium primary battery according to claim 3.

5. The length of the aforementioned base layer is 7 mm to 50 mm, and the width is 4 mm to 40 mm. The thickness of the aforementioned base material layer is 0.001 mm to 0.3 mm. The material of the aforementioned base layer is a fibrous material. The lithium primary battery according to claim 1.

6. The length of the base 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. The lithium primary battery according to claim 5.

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

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

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

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

11. The device further includes a cover plate assembly, a positive electrode pole and a liquid injection port provided on the cover plate assembly, the cover plate assembly further includes a through hole, and the positive electrode pole is connected to the positive electrode via a first current collection network through the through hole. The lithium primary battery according to claim 1.

12. Two negative electrodes are provided, and the two negative electrodes are positioned opposite each other on both sides of the positive electrode. The lithium primary battery further includes a second current collection network connecting the two negative electrodes. The lithium primary battery according to claim 1.

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