Primary lithium-manganese battery and method for processing the same

Abstract

The application belongs to the technical field of primary lithium-manganese batteries, and particularly provides a primary lithium-manganese battery pack and a processing method thereof. The primary lithium-manganese battery pack comprises an outer shell and a plurality of single batteries, the single battery comprises a battery shell, an electrode group and an electrolyte encapsulated in the battery shell, the electrode group comprises a positive electrode sheet, a negative electrode sheet and a separator, the negative electrode sheet is composed of a metal lithium sheet or a lithium alloy sheet and a copper foil, the positive electrode sheet is composed of an aluminum foil and a positive electrode active material coated on the aluminum foil, and the positive electrode active material comprises an electrolytic manganese dioxide composite material, a conductive agent and a binder, the electrolytic manganese dioxide composite material is electrolytic manganese dioxide which is first passivated and then grafted with a polyether compound. The single battery has good high-temperature storage stability and relatively high discharge capacity at low temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of primary lithium-manganese batteries, and particularly relates to a primary lithium-manganese battery pack and a processing method thereof. BACKGROUND

[0002] Primary batteries refer to chemical power systems that cannot be recharged and reused after discharge. Among them, primary lithium-manganese batteries with manganese dioxide as the positive active material and lithium metal as the negative active material have the advantages of high specific energy, stable discharge, long storage life, and have been widely used in the fields of miniature electronic devices, memory backup, intelligent instruments, medical devices and military equipment.

[0003] Nowadays, due to the increasing complexity of terminal equipment and the more diverse use environment, primary lithium-manganese batteries are required to have higher energy density, longer life, wider working temperature range and more reliable safety. In order to meet these requirements, multiple primary lithium-manganese single batteries need to be combined into a primary lithium-manganese battery pack through series connection, parallel connection or series-parallel hybrid connection, so as to obtain higher voltage, greater capacity, etc.

[0004] However, when the positive manganese dioxide surface directly contacts with the electrolyte under high-temperature storage, long-term floating charge or high-voltage conditions, the unsaturated coordination active sites and oxygen vacancies existing on the surface of the manganese dioxide can catalyze the oxidation and decomposition of the electrolyte on the surface, thereby causing the capacity attenuation and internal resistance increase of the battery. Therefore, in the primary lithium-manganese battery pack, there is inconsistency in capacity, internal resistance, self-discharge rate, etc. between multiple primary lithium-manganese single batteries, and in the use process, this inconsistency will be amplified, thereby causing a series of accelerated aging, performance degradation, and even safety hazards.

[0005] In order to reduce the oxidation of the electrolyte, the commonly used method is to modify the electrolyte, for example, adding an antioxidant or using a solvent with strong antioxidant property. The patent application file with publication number CN120824425A discloses an electrolyte for lithium-manganese oxide lithium ion battery and a preparation method thereof. The electrolyte includes an organic solvent, a lithium salt and an additive, the additive includes a manganese ion complexing agent, a film forming promoter and an antioxidant, the antioxidant can inhibit the electrolyte oxidation and decomposition caused by manganese ions at high temperature, but this method may increase the viscosity of the electrolyte, thereby causing the wettability of the electrolyte to be poor, thereby affecting the transmission of lithium ions, causing the battery performance to decline. SUMMARY

[0006] In order to solve the above problems, reduce the oxidation and decomposition of the electrolyte, and improve the performance of the battery pack, the present application provides a primary lithium-manganese battery pack and a processing method thereof.

[0007] The application provides a primary lithium-manganese battery, which comprises an outer shell, a plurality of single batteries, the single battery comprises a battery shell, an electrode group and an electrolyte which are encapsulated in the battery shell, the electrode group comprises a positive electrode sheet, a negative electrode sheet and a diaphragm, the negative electrode sheet is a composite of a lithium metal sheet or a lithium alloy sheet and a copper foil, the positive electrode sheet is composed of an aluminum foil and a positive electrode active material coated on the aluminum foil, the positive electrode active material comprises an electrolytic manganese dioxide composite material, a conductive agent and a binder, and a preparation method of the electrolytic manganese dioxide composite material.

[0008] S1: reacting the electrolytic manganese dioxide with an amino silane under nitrogen protection to obtain aminated manganese dioxide;

[0009] S2: reacting the aminated manganese dioxide with a phosphonic acid-based carboxylic acid to obtain passivated manganese dioxide;

[0010] S3: reacting the passivated manganese dioxide with an epoxy polyether compound under nitrogen protection and the action of a catalyst.

[0011] Further, the diaphragm is a polyolefin diaphragm.

[0012] Further, the electrolyte is a solution with a concentration of 0.1-1.5 mol / L prepared by dissolving a lithium salt in an organic solvent.

[0013] Further, the lithium salt is lithium hexafluorophosphate or lithium tetrafluoroborate.

[0014] And / or, the organic solvent is an ester solvent.

[0015] Further, the conductive agent is conductive carbon black; and / or, the binder is polyvinylidene fluoride.

[0016] Further, in the step S1, the amino silane is one of gamma-aminopropyl triethoxysilane, N-(beta-aminoethyl)-gamma-aminopropyl trimethoxysilane and N-(beta-aminoethyl)-gamma-aminopropyl triethoxysilane; and the mass ratio of the electrolytic manganese dioxide to the amino silane is 100: (1-5).

[0017] Further, in the step S2, the phosphonic acid-based carboxylic acid is one of 2-hydroxyphosphonoacetic acid, 2-carboxyethyl phenyl phosphinic acid and 2-phosphonic acid butane-1,2,4-tricarboxylic acid.

[0018] And / or, the mass ratio of the aminated manganese dioxide to the phosphonic acid-based carboxylic acid is 100: (0.5-2).

[0019] Further, in the step S2, the catalyst is a Lewis acid.

[0020] Further, the step S3, the epoxy polyether compound is polyethylene glycol diglycidyl ether or polypropylene glycol diglycidyl ether.

[0021] Further, the mass ratio of the passivated manganese dioxide and the epoxy polyether compound is 100: (1-5).

[0022] The application also provides a processing method of a primary lithium-manganese battery, comprising the following steps:

[0023] (1) laminating and winding the positive electrode sheet, the diaphragm and the negative electrode sheet, then inserting into the battery shell, welding the positive and negative electrodes, injecting the electrolyte, standing, sealing, forming, aging, detecting, sorting, and obtaining the single battery;

[0024] (2) electrically connecting the single battery, installing the protection device and the wire, insulating the whole, then putting into the outer shell, and finally testing, aging and inspecting.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] 1. The phosphonic acid group with strong coordination ability in the application is combined with the manganese active sites and oxygen vacancies on the surface of the electrolytic manganese dioxide, the catalytic oxidation active sites on the surface of the electrolytic manganese dioxide are passivated, the catalytic oxidation ability of these active sites on the electrolyte is reduced, thereby reducing the consumption of the electrolyte and improving the service life of the battery.

[0027] 2. The flexible polyether chain segment is grafted on the surface of the electrolytic manganese dioxide in the application, the ether oxygen atom can coordinate with lithium ions, thereby promoting the transmission of lithium ions, and the flexible chain segment is also conducive to improving the wettability of the electrolyte on the electrode surface, thereby reducing the interface impedance.

[0028] 3. The surface of the electrolytic manganese dioxide in the application can form a stable flexible interface layer, which can effectively block the direct contact between the electrolyte and the surface of the electrolytic manganese dioxide, thereby making the electrolyte not easy to be catalytically oxidized, reducing the consumption of the electrolyte and prolonging the service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the assembly diagram of the battery of the embodiment 1 of the application.

[0030] Figure 2 It is the curve of the relative discharge capacity of the single battery of the embodiment and the control group of the application with temperature.

[0031] Mark explanation: 1 refers to the single battery, 2 refers to the insulating sheet, 3 refers to the terminal, and 4 refers to the outer shell. DETAILED DESCRIPTION

[0032] In order to make the inventive purposes, technical solutions and beneficial technical effects of the present application clearer, the present application is further described in detail below in combination with embodiments, and the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0034] In the case of using "comprising", "having", and "including" described herein, it is intended to cover non-exclusive inclusion, unless the explicit limiting term such as "only", "consisting of", etc. is used, another component can be added.

[0035] The words "preferably", "more preferably", "preferably", "more preferably" and the like in the present application refer to the embodiments of the present application which can provide certain beneficial effects in some cases. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present application. That is, in the present application, "preferably", "more preferably", "preferably", "more preferably" and the like only describe the implementation or embodiment with better effect, but do not constitute a limitation on the protection scope of the present application.

[0036] In the present application, "further", "more further", "in particular" and the like are used to describe the purpose, indicating the difference in content, but should not be understood as a limitation on the protection scope of the present application.

[0037] In the present application, "at least one" means more than one, such as one, two and more than two. The meaning of "multiple" or "several" is at least two, such as two, three, etc. The meaning of "multiple layers" is at least two layers, such as two layers, three layers, etc. unless otherwise explicitly specified. In the description of the present application, the meaning of "several" is at least one, such as one, two, etc. unless otherwise explicitly specified.

[0038] When a range of values is disclosed herein, the range is to be construed as having endpoints that are included in the range, and each value within the range is also included in the range. Further, a range includes each individual number between (and including) the endpoints of the range, unless otherwise indicated. Likewise, a range includes each individual value within the range, unless otherwise indicated. Further, a range includes the minimum and maximum values of the range, unless otherwise indicated. Additionally, a range includes each individual value within the range, unless otherwise indicated. Further, when a range is provided, it is intended to include each individual number within the range, unless otherwise indicated.

[0039] Unless otherwise indicated, all steps of the application can be performed in any order. For example, the method comprises steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method can further comprise step (c) means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc. Unless otherwise indicated, the singular forms "a", "an" and "the" include plural referents, and are not to be construed as meaning one.

[0040] In the present application, "above" or "below" includes the number itself. For example, 1 below includes 1.

[0041] In the present application, room temperature refers to 0-40℃, including but not limited to 10-40℃, or further 20-30℃.

[0042] The present application provides a primary lithium-manganese battery pack, comprising an outer shell, a plurality of single batteries, the single battery comprising a battery shell, an electrode group and an electrolyte encapsulated in the battery shell, the electrode group comprising a positive electrode sheet, a negative electrode sheet and a separator, the negative electrode sheet being a metal lithium sheet or a lithium alloy sheet compounded with a copper foil, the positive electrode sheet being composed of an aluminum foil and a positive electrode active material coated on the aluminum foil, the positive electrode active material comprising an electrolytic manganese dioxide composite material, a conductive agent and a binder, and the preparation method of the electrolytic manganese dioxide composite material comprising the following steps:

[0043] S1: under the protection of nitrogen, electrolytic manganese dioxide reacts with amino silane to obtain aminated manganese dioxide;

[0044] S2: aminated manganese dioxide reacts with phosphonic acid-based carboxylic acid to obtain passivated manganese dioxide;

[0045] S3: under the protection of nitrogen and the action of a catalyst, passivated manganese dioxide reacts with an epoxy polyether compound.

[0046] In some embodiments of the present application, the phosphonic acid group in the phosphonic acid-based carboxylic acid can interact with active sites, oxygen vacancies and defects on the surface of electrolytic manganese dioxide, so that the surface of the electrolytic manganese dioxide is partially passivated, thereby reducing the catalytic oxidation of the electrolyte by the active sites, oxygen vacancies and defects. Moreover, after the passivated manganese dioxide surface is grafted with a flexible polyether compound, the ether oxygen atoms can coordinate with lithium ions to form a local environment similar to the electrolyte, thereby promoting lithium ion transport and making it easier for lithium ions to react by intercalating into the manganese dioxide lattice, thus increasing the energy density of the battery pack, improving the stability of the battery pack and prolonging the service life of the battery pack. In addition, the flexible polyether chain segment can improve the wettability of the electrode surface, thereby reducing the interfacial impedance, and the flexible polyether chain segment can also effectively hinder direct contact between the electrolyte and the manganese dioxide surface, thereby preventing the electrolyte from being catalytically oxidized, thus reducing the consumption of the electrolyte and prolonging the service life of the battery pack.

[0047] In some embodiments of the present application, the separator is a polyolefin separator, for example, a polyethylene separator or a polypropylene separator.

[0048] In some embodiments of the present application, the electrolyte is a solution prepared by dissolving a lithium salt in an organic solvent, and the concentration is 0.1-1.5 mol / L; for example, the concentration can be 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L or 1.5 mol / L.

[0049] In some embodiments of the present application, the lithium salt is lithium hexafluorophosphate or lithium tetrafluoroborate.

[0050] In some embodiments of the present application, the organic solvent is an ester solvent, for example, a chain carbonate, a cyclic carbonate, a chain ester or a cyclic ester.

[0051] In some specific embodiments of the present application, the conductive agent is carbon black; and / or the binder is polyvinylidene fluoride.

[0052] In some embodiments of the present application, in step S1, the amino silane is one of γ-aminopropyl triethoxysilane, N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane and N-(β-aminoethyl)-γ-aminopropyl triethoxysilane; and the mass ratio of the electrolytic manganese dioxide to the amino silane is 100: (1-5), for example, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5 or 100:5.

[0053] The amino silane can form a strong interaction with the surface of electrolytic manganese dioxide, thereby improving the passivation stability, and in subsequent battery assembly and cycling, the flexible interface layer is not easy to fall off, dissolve or migrate from the surface of the electrolytic manganese dioxide.

[0054] In some embodiments of the present application, in the step S2, the phosphonic acid-based carboxylic acid is one of 2-hydroxyphosphonooxyacetic acid, 2-carboxyethyl phenyl phosphinic acid and 2-phosphonic acid-based butane-1,2,4-tricarboxylic acid;

[0055] And / or, the mass ratio of the aminated manganese dioxide and the phosphonic acid-based carboxylic acid is 100:(0.5-2); for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2.

[0056] In some embodiments of the present application, in the step S2, the catalyst is a Lewis acid, and further preferably, in the step S2, the catalyst is boron trifluoride etherate complex.

[0057] In some specific embodiments of the present application, in the step S3, the epoxy polyether compound is polyethylene glycol diglycidyl ether or polypropylene glycol diglycidyl ether.

[0058] The polyether segment grafted on the surface of the electrolytic manganese dioxide not only can interact with lithium ions, but also has good flexibility, which is conducive to the transmission of lithium ions, and can also hinder the direct contact of the electrolyte with the electrolytic manganese dioxide, thereby reducing the oxidative decomposition of the electrolyte.

[0059] And / or, the mass ratio of the passivated manganese dioxide and the epoxy polyether compound is 100:(1-5), for example, it can be 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5.

[0060] In addition, the present application also provides a processing method of a primary lithium-manganese battery, which comprises the following steps:

[0061] (1) After the positive electrode sheet, the diaphragm and the negative electrode sheet are laminated and wound, they are inserted into the battery shell, the positive and negative electrodes are welded, the electrolyte is injected, and then the single battery is obtained after standing, sealing, formation, aging, detection, sorting, etc.

[0062] (2) The single battery is electrically connected, the protection device and the lead wire are installed, the whole is insulated, and then it is put into the outer shell, and finally it is tested, aged and inspected.

[0063] The present application will be further described below by way of examples, but the scope of the present application is not limited thereto.

[0064] When the embodiments give numerical ranges, it is understood that unless the application specifically states to the contrary, the two endpoints and any number between the two endpoints of every numerical range is optional. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Unless specific conditions are indicated in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. Unless the manufacturer of all reagents or instruments is specified, all are conventional products that can be purchased on the market. In addition to the specific methods, devices, materials used in the embodiments, any method, device and material of the prior art similar or equivalent to the methods, devices and materials described in the embodiments of the application can also be used to implement the application according to the mastery of the prior art by those skilled in the art and the description of the application.

[0065] Embodiment 1

[0066] The lithium-manganese battery of the embodiment comprises an outer shell, six single batteries, the single battery comprising a battery shell, an electrode group and an electrolyte encapsulated in the battery shell, the electrode group comprising a positive electrode sheet, a negative electrode sheet and a polypropylene separator;

[0067] The preparation method of the electrolyte is as follows: first, γ-valerolactone and propylene carbonate are mixed uniformly at a volume ratio of 1:1 to obtain a mixed solvent, then lithium hexafluorophosphate is added to the mixed solvent and mixed uniformly to prepare a solution with a concentration of 1 mol / L, and the electrolyte is obtained.

[0068] The preparation method of the positive electrode sheet is as follows: 92 g of electrolytic manganese dioxide composite material, 4 g of acetylene carbon black and 4 g of polyvinylidene fluoride are weighed and added to 500 mL of N-methylpyrrolidone, mixed uniformly and ground into a uniform slurry, then the slurry is uniformly coated on an aluminum foil current collector, dried at 120℃ for 12 h, rolled and cut to obtain the positive electrode sheet.

[0069] The preparation method of the negative electrode sheet is as follows: high-purity lithium ingot is melted under argon protection, then rolled into a continuous lithium strip with uniform thickness by a rolling mill, and the lithium strip is compounded on one side of a copper foil and cut to obtain the negative electrode sheet.

[0070] The preparation method of the electrolytic manganese dioxide composite material of the embodiment comprises the following steps:

[0071] S1: 10 g of electrolytic manganese dioxide powder and 200 mL of toluene are weighed and placed in a flask, ultrasonically dispersed for 30 min, 0.3 g of γ-aminopropyltriethoxysilane is added under nitrogen protection while stirring, the temperature is raised to 80℃, and refluxed for 12 h. After the reaction is completed, the temperature is cooled to room temperature, centrifugal separation is performed, and the product is washed with toluene and ethanol in sequence, and vacuum dried at 60℃ for 6 h to obtain aminated manganese dioxide.

[0072] S2: take 20 g of aminomanganese dioxide and 200 ml of dimethyl sulfoxide, place them in a flask, and ultrasonically disperse for 30 min to obtain a suspension; take 0.2 g of 2-hydroxyphosphonoacetic acid, 0.15 g of N-hydroxysuccinimide, 0.24 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, and 20 ml of dimethyl sulfoxide, stir for 30 min to obtain a phosphonic acid mixture; slowly add the phosphonic acid mixture to the suspension, heat to 40℃ under nitrogen protection, and stir for 12 h; after the reaction is completed, wash with dimethyl sulfoxide and anhydrous ethanol in sequence, and dry the product at 60℃ under vacuum for 6 h to obtain passivated manganese dioxide;

[0073] S3: take 30 g of the passivated manganese dioxide, add 150 ml of tetrahydrofuran, ultrasonically disperse for 30 min, heat to 50℃ under nitrogen protection, add 0.9 g of polyethylene glycol diglycidyl ether and 1 μl of boron trifluoride ether complex catalyst in sequence, continuously stir for 6 h, cool to room temperature after the reaction is completed, centrifugally wash with tetrahydrofuran and acetone in sequence twice, and dry the product at 60℃ under vacuum for 12 h to obtain;

[0074] The processing method of the primary lithium-manganese battery of the embodiment comprises the following steps:

[0075] (1) stack the positive electrode sheet, the polypropylene diaphragm, and the negative electrode sheet in sequence and precisely wind them to obtain a winding core, insert the winding core into a nickel-plated steel shell, then perform positive and negative electrode welding, inject electrolyte into the battery in a drying chamber, then stand still to allow the electrolyte to be fully soaked, place an insulating sealing ring and a positive cap assembly, seal, finally perform formation, aging, detection, and sorting to obtain a CR17450 monomer battery;

[0076] (2) place the monomer batteries in a customized support in the order of three monomer batteries in one group, a total of two groups, and paste an insulating sheet on the pole surface of the monomer batteries, then perform parallel welding, series welding, and total tab welding, then install a one-time fuse, weld a lead wire and a terminal, then bundle and insulate the whole, place it in an ABS outer shell, fill the gap with heat-conducting silicone, and finally perform testing, aging, and inspection.

[0077] Control group 1

[0078] The primary lithium-manganese battery of the control group comprises an outer shell and six monomer batteries, the monomer battery comprises a battery shell, an electrode group encapsulated in the battery shell, and electrolyte, and the electrode group comprises a positive electrode sheet, a negative electrode sheet, and a polypropylene diaphragm;

[0079] The preparation method of the electrolyte is: firstly, uniformly mixing gamma-valerolactone and propylene carbonate in a volume ratio of 1:1 to obtain a mixed solvent, then adding lithium hexafluorophosphate into the mixed solvent, uniformly mixing, and preparing a solution with a concentration of 1 mol / L, thereby obtaining the electrolyte;

[0080] The preparation method of the positive electrode sheet is: weighing 92g of electrolytic manganese dioxide, 4g of acetylene carbon black and 4g of polyvinylidene fluoride, adding them into 500mL of N-methylpyrrolidone, uniformly mixing and grinding into a uniform slurry, then uniformly coating the slurry on an aluminum foil current collector, drying at 120℃ for 12h, cutting after rolling, thereby obtaining the positive electrode sheet;

[0081] The preparation method of the negative electrode sheet is: melting high-purity lithium ingot under argon protection, then rolling into a continuous lithium strip with uniform thickness by a rolling mill, then compositing the lithium strip on one side of a copper foil, and cutting, thereby obtaining the negative electrode sheet;

[0082] The processing method of the lithium-manganese battery of the control group is the same as that of Example 1.

[0083] Control group 2

[0084] The lithium-manganese battery of the control group comprises an outer shell and six single batteries, wherein each single battery comprises a battery shell, an electrode group and an electrolyte, the electrode group comprises a positive electrode sheet, a negative electrode sheet and a polypropylene separator;

[0085] The preparation method of the electrolyte is: firstly, uniformly mixing gamma-valerolactone and propylene carbonate in a volume ratio of 1:1 to obtain a mixed solvent, then adding lithium hexafluorophosphate into the mixed solvent, uniformly mixing, and preparing a solution with a concentration of 1 mol / L, thereby obtaining the electrolyte;

[0086] The preparation method of the positive electrode sheet is: weighing 92g of electrolytic manganese dioxide composite material, 4g of acetylene carbon black and 4g of polyvinylidene fluoride, adding them into 500mL of N-methylpyrrolidone, uniformly mixing and grinding into a uniform slurry, then uniformly coating the slurry on an aluminum foil current collector, drying at 120℃ for 12h, cutting after rolling, thereby obtaining the positive electrode sheet;

[0087] The preparation method of the negative electrode sheet is: melting high-purity lithium ingot under argon protection, then rolling into a continuous lithium strip with uniform thickness by a rolling mill, then compositing the lithium strip on one side of a copper foil, and cutting, thereby obtaining the negative electrode sheet;

[0088] The preparation method of the electrolytic manganese dioxide composite material of the embodiment comprises the following steps:

[0089] S1: take 10 g of electrolytic manganese dioxide powder and 200 mL of toluene, place in a flask, ultrasonic dispersion for 30 min, under nitrogen protection, while stirring, add 0.3 g of γ-aminopropyltriethoxysilane, heat to 80°C, reflux for 12 h, after the reaction is completed, cool to room temperature, centrifugal separation, and sequentially wash with toluene, ethanol, the product is dried under vacuum at 60°C for 6 h, to obtain aminated manganese dioxide;

[0090] S2: take 20 g of aminated manganese dioxide and 200 mL of dimethyl sulfoxide, place in a flask, ultrasonic dispersion for 30 min, to obtain a suspension; take 0.2 g of 2-hydroxyphosphonoacetic acid, 0.15 g of N-hydroxysuccinimide, 0.24 g of 1-ethyl-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride, and 20 mL of dimethyl sulfoxide, stir for 30 min, to obtain a phosphonic acid mixture; slowly drop the phosphonic acid mixture into the suspension, heat to 40°C under nitrogen protection, stir for 12 h, after the reaction is completed, sequentially wash with dimethyl sulfoxide, anhydrous ethanol, the product is dried under vacuum at 60°C for 6 h, to obtain;

[0091] The processing method of the lithium-manganese battery of the control group is the same as that of Example 1.

[0092] Performance detection

[0093] 1. High-temperature storage performance test:

[0094] ①Take a number of single batteries of Example 1 and control group 1-2 that have completed formation, weigh the initial mass of each single battery, denoted as M0, measure the open-circuit voltage at 25°C, denoted as OCV0, discharge at 0.2C rate to 2.0V at 25°C, test the initial capacity, denoted as C0, use a battery tester, apply a 1C current pulse (such as 1A) for 100 ms, calculate ΔV / ΔI, to obtain the direct current internal resistance, denoted as DCIR0.

[0095] ②Place the single battery whose initial data has been recorded in an oven at 60°C in an open-circuit state, store for 30 days, take out and place in a 25°C, 50%RH environment for 24 h, weigh again using an analytical balance, denoted as M 30 , measure the voltage after storage, denoted as OCV 30 , measure the internal resistance after storage, denoted as DCIR 30 , measure the remaining capacity of the battery after storage, denoted as C 30 , and calculate the electrolyte consumption rate=(M0-M 30 ) / injected electrolyte mass×100%; capacity retention rate=C 30 / C0×100%; voltage retention rate=OCV 30 / OCV0×100%; internal resistance growth rate=(DCIR 30DCIR0) / DCIR0x 100%, and the results are shown in Table 1.

[0096] Table 1 High temperature storage performance of single batteries of Example 1 and Control Groups 1-2

[0097]

[0098] Comparing the data of the example and the control groups in Table 1, it can be seen that the single battery of Example 1 has better high temperature storage stability, which indicates that the partial passivation and grafting of the polyether compound on the surface of the electrolytic manganese dioxide forms a stable flexible interface layer, which on one hand effectively reduces the catalytic oxidation of the electrolyte on the surface of the electrolytic manganese dioxide, and may also reduce the side reaction of the negative electrode, thereby reducing the electrolyte consumption rate; on the other hand, it reduces the loss of positive and negative active materials, and can promote the transmission of lithium ions and improve the wettability of the electrode surface, so the capacity retention rate is higher, the interface impedance is reduced, and the internal resistance growth rate is also lower.

[0099] 2. Discharge capacity test at different temperatures:

[0100] Take several single batteries of Example 1 and Control Groups 1-2 that have completed formation, take three single batteries and place them at 25°C for 24h, then discharge at 0.2C rate to 2.0V, test the discharge capacity, take the average value as the reference discharge capacity q 基准 , take another 12 single batteries, divide them into 4 groups, and place them in test boxes at 0°C, -10°C, -20°C, and -30°C respectively, and keep the test boxes running for 12h, immediately discharge at 0.2C rate to 2.0V, record the average value of the discharge capacity of each group, and record it as Q0, Q -10 , Q -20 , Q -30 , calculate the relative discharge capacity at each temperature according to the formula relative discharge capacity = Q / q 基准 x 100%, and draw the temperature-relative discharge capacity curve, as shown in Figure 2 .

[0101] Comparing Figure 2 the data of the example and the control groups in Table 1, it can be seen that the relative discharge capacity of the single battery in Example 1 is higher at the same temperature, which indicates that the low temperature stability of the single battery of Example 1 is better, which may be because the partial passivation and grafting of the polyether compound on the surface of the electrolytic manganese dioxide can promote the transmission of lithium ions and reduce the charge transfer impedance at low temperature.

[0102] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified by those skilled in the art, or some technical features thereof can be replaced by equivalents, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A primary lithium-manganese battery pack, characterized in that: The device includes an outer casing and multiple individual battery cells. Each individual battery cell includes a battery case, an electrode assembly encapsulated within the battery case, and an electrolyte. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The negative electrode is composed of a composite of lithium metal sheet and copper foil or a composite of lithium alloy sheet and copper foil. The positive electrode is composed of aluminum foil and a positive electrode active material coated on the aluminum foil. The positive electrode active material includes an electrolytic manganese dioxide composite material, a conductive agent, and a binder. The preparation method of the electrolytic manganese dioxide composite material includes the following steps: S1: Under nitrogen protection, manganese dioxide is electrolyzed and reacted with aminosilane to obtain aminated manganese dioxide; the aminosilane is one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane. S2: Aminated manganese dioxide reacts with phosphonic acid to obtain passivated manganese dioxide; the phosphonic acid is one of 2-hydroxyphosphonoacetic acid, 2-carboxyethylphenyl hypophosphite, and 2-phosphobutane-1,2,4-tricarboxylic acid. S3: Passivated manganese dioxide is reacted with an epoxy polyether compound under nitrogen protection and catalysis to obtain the product; the epoxy polyether compound is polyethylene glycol diglycidyl ether or polypropylene glycol diglycidyl ether.

2. The primary lithium-manganese battery pack according to claim 1, characterized in that: The diaphragm is a polyolefin diaphragm.

3. A primary lithium-manganese battery pack according to claim 1, characterized in that: The electrolyte is a 0.1-1.5 mol / L solution prepared by dissolving lithium salt in an organic solvent.

4. A primary lithium-manganese battery pack according to claim 3, characterized in that: The lithium salt is lithium hexafluorophosphate or lithium tetrafluoroborate; and / or, the organic solvent is an ester solvent.

5. A primary lithium-manganese battery pack according to claim 1, characterized in that: The conductive agent is conductive carbon black; and / or the binder is polyvinylidene fluoride.

6. A primary lithium-manganese battery pack according to claim 1, characterized in that: In step S1, the mass ratio of electrolytic manganese dioxide to aminosilane is 100:(1-5).

7. A primary lithium-manganese battery pack according to claim 1, characterized in that: In step S2, the mass ratio of aminated manganese dioxide to phosphonic acid carboxylic acid is 100:(0.5-2).

8. A primary lithium-manganese battery pack according to claim 1, characterized in that: In step S3, the catalyst is a Lewis acid.

9. A primary lithium-manganese battery pack according to claim 1, characterized in that: In step S3, the mass ratio of passivated manganese dioxide to epoxy polyether compound is 100:(1-5).

10. A method for processing a primary lithium-manganese battery pack according to any one of claims 1-9, characterized in that: Includes the following steps: (1) The positive electrode, separator and negative electrode are stacked and wound, then inserted into the battery case, the positive and negative electrodes are welded, electrolyte is injected, and the cells are left to stand, sealed, formed, aged, tested and sorted to obtain a single cell. (2) Connect the individual cells electrically, install the protective devices and wires, insulate the whole structure, put it into the outer casing, and finally test, age and inspect.

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