Lithium primary battery

Abstract

This lithium primary battery comprises a positive electrode, a negative electrode, and a nonaqueous electrolytic solution. The positive electrode contains a positive electrode mix. The positive electrode mix contains LixMnO2 (0 ≤ x ≤ 0.05) and a sulfuric acid salt. The amount of sulfur atoms contained in the positive electrode mix is no greater than 1.6 parts by mass per 100 parts by mass of manganese atoms contained in the positive electrode mix. The negative electrode contains an alloy comprising lithium and magnesium. The magnesium content in the alloy is 0.01 to 10 mass%, and the lithium content in the alloy exceeds 88 mass%.

Description

Lithium primary battery

[0001] The present disclosure relates to lithium primary batteries.

[0002] Lithium primary batteries are used as power sources for many electronic devices due to their high energy density and low self-discharge. Manganese dioxide or the like is used for the positive electrode of a lithium primary battery. For example, sheet-shaped (foil-shaped) lithium metal or a lithium alloy is used for the negative electrode of a lithium primary battery.

[0003] Patent Document 1 proposes "a lithium negative electrode in which a lithium salt is dissolved in an electrolyte, and a separator is placed opposite the negative electrode, in which an aluminum-magnesium alloy coating layer is initially laminated on the surface of the lithium body adjacent to the separator, and an aluminum-magnesium-lithium ternary alloy is formed by diffusion, increasing the surface area of ​​the negative electrode and improving the pulse performance of the battery."

[0004] Furthermore, Patent Document 2 describes manganese dioxide containing sulfate radicals (claim 2).

[0005] JP 58-209862 A JP 2005-038839 A

[0006] Lithium primary batteries may experience an increase in internal resistance and a decrease in discharge characteristics after long-term storage.

[0007] One aspect of the present disclosure is a battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte solution, the positive electrode including a positive electrode mixture, and the positive electrode mixture including Li ｘ MnO ２ (0≦x≦0.05) and a sulfate, wherein the amount of sulfur atoms contained in the positive electrode mixture is 1.6 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture, and the negative electrode includes an alloy containing lithium and magnesium, wherein the content of the lithium in the alloy is more than 88% by mass, and the content of the magnesium in the alloy is 0.01% by mass or more and 10% by mass or less.

[0008] According to the present disclosure, it is possible to suppress the deterioration of discharge characteristics of a lithium primary battery after long-term storage.

[0009] The novel features of the present invention are set forth in the appended claims, but the present invention, both in terms of structure and content, together with other objects and features of the present invention, will be better understood from the following detailed description taken in conjunction with the drawings.

[0010] FIG. 1 is a partially cross-sectional front view of a lithium primary battery according to an embodiment of the present disclosure.

[0011] The following describes embodiments of the present disclosure using examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may be applied as long as the effects of the present disclosure are obtained. In this specification, the term "numerical value A to numerical value B" includes numerical value A and numerical value B and can be read as "numerical value A or more and numerical value B or less." In the following description, when lower and upper limits are exemplified for numerical values ​​of specific physical properties or conditions, any of the exemplified lower limits and any of the exemplified upper limits can be arbitrarily combined, as long as the lower limit is not equal to or greater than the upper limit. When multiple materials are exemplified, one of the materials may be selected and used alone, or two or more materials may be used in combination.

[0012] A lithium primary battery according to an embodiment of the present disclosure includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode mixture, and the positive electrode mixture includes a positive electrode active material, Li ｘ MnO ２ (0≦x≦0.05) and a sulfate. The amount of sulfur atoms (S) contained in the positive electrode mixture is 1.6 parts by mass or less per 100 parts by mass of manganese atoms (Mn) contained in the positive electrode mixture. The negative electrode contains a lithium alloy. The lithium alloy contains more than 88% by mass of lithium (Li) and 0.01% by mass or more and 10% by mass or less of magnesium (Mg).

[0013] When the above configuration is satisfied, an increase in internal resistance after long-term storage and a resulting decrease in discharge characteristics (storage characteristics) are suppressed. For example, a voltage drop during low-temperature pulse discharge after storage is suppressed. While the detailed mechanism is unknown, it is speculated as follows. During long-term storage, sulfate contained in the positive electrode mixture elutes from the positive electrode and precipitates on the negative electrode. Components derived from the sulfate (sulfate ions) are captured in a coating formed on the negative electrode surface upon contact between the negative electrode and the nonaqueous electrolyte. If the dispersion of sulfate ions in the coating is low, Li ions may be less likely to move within the coating, resulting in an increase in negative electrode resistance. In contrast, if the negative electrode (Li alloy) contains Mg, some kind of interaction occurs between the Mg and sulfate ions, improving the dispersion of sulfate ions in the coating and suppressing the increase in negative electrode resistance. The good dispersion of Mg is thought to be involved in this interaction.

[0014] If the amount of sulfur atoms contained in the positive electrode mixture is greater than 1.6 parts by mass per 100 parts by mass of manganese atoms contained in the positive electrode mixture, the coating will contain an excess of sulfate-derived components, which may increase the negative electrode resistance during storage and deteriorate the discharge characteristics even if Mg is contained in the negative electrode.If the Mg content in the lithium alloy is less than 0.01% by mass, the effect of containing Mg in the negative electrode will be reduced, and the negative electrode resistance may increase during storage and deteriorate the discharge characteristics.

[0015] If the Li content in the lithium alloy is 88% by mass or less, the proportion of Li in the negative electrode will be small, which may increase the negative electrode resistance and deteriorate the discharge characteristics. If the Mg content in the lithium alloy is more than 10% by mass, the proportion of Mg in the negative electrode will be large, which may increase the negative electrode resistance and deteriorate the discharge characteristics.

[0016] The sulfur atoms come from sulfates (sulfate ions). Sulfates (sulfate ions) are contained in manganese dioxide, which will be described in detail later. Most or all of the manganese atoms are Li ｘ MnO ２ A small proportion of manganese atoms may be present in sulfates as manganese sulfate.

[0017] The amount of sulfur atoms contained in the positive electrode mixture may be 0.25 parts by mass or more (or 0.5 parts by mass or more) and 1.6 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture. When the amount of sulfur atoms contained is high within the above range, storage characteristics tend to deteriorate, and therefore the effect of improving storage characteristics by adding Mg to the lithium alloy is significantly obtained. When the amount of sulfur atoms contained in the positive electrode mixture is high within the above range, the storage characteristics can be improved by adding Mg to the lithium alloy, which can reduce the number of steps by simplifying the cleaning process described below, reduce cleaning costs, and reduce environmental impact.

[0018] The amount (parts by mass) of sulfur atoms contained in the positive electrode mixture can be determined as follows. An initial battery (for example, an unused battery immediately after manufacture or within one week of purchase) is disassembled to remove the positive electrode mixture, which is then dissolved in an acid solution (such as hydrochloric acid). The insoluble matter is separated by filtration or centrifugation to obtain a sample solution. The amount of S (WS) (mass%) and the amount of Mn (WMn) (mass%) in the sample solution are measured using inductively coupled plasma (ICP) atomic emission spectroscopy, and the amount (parts by mass) of sulfur atoms is calculated as (WS / WMn) x 100. For example, a Thermo Fisher Scientific "iCAP7400 Duo" can be used as the measurement device.

[0019] (Lithium Alloy) From the viewpoint of reducing internal resistance and ensuring capacity, the Li content in the lithium alloy is more than 88 mass%, and may be 89 mass% or more, 90 mass% or more, or even 95 mass% or more. From the viewpoint of suppressing deterioration of storage characteristics, the Mg content in the lithium alloy is 0.01 mass% or more and 10 mass% or less.

[0020] From the viewpoint of improving storage characteristics, it is preferable that the lithium alloy further contains Al. Hereinafter, a lithium alloy containing Mg but substantially no Al will also be referred to as a "Li-Mg alloy." A lithium alloy containing Mg and Al will also be referred to as a "Li-Mg-Al alloy." Note that "substantially no Al" means that the content is below the detection limit in composition analysis of the lithium alloy (for example, ICP atomic emission spectroscopy, atomic absorption spectroscopy, etc.).

[0021] While the addition of Al suppresses the increase in internal resistance during storage (long-term use), Al is prone to segregation in Li. On the other hand, Mg has very good dispersibility in Li. When a lithium alloy contains both Mg and Al, the good dispersibility of Mg suppresses Al segregation, and uneven Li consumption due to Al segregation is suppressed. In this case, the effects of Mg and Al are stably obtained throughout the negative electrode, and Li is uniformly consumed on the negative electrode surface, resulting in a larger proportion of Li that can contribute to the discharge reaction at the end of discharge. When Al is contained together with Mg, a low-resistance coating is easily formed stably, the voltage at the end of discharge is further increased, and the deterioration of storage characteristics is further suppressed.

[0022] From the viewpoint of suppressing deterioration of storage characteristics, the Mg content in the lithium alloy is 0.01% by mass or more, preferably 0.05% by mass or more, and more preferably 0.1% by mass or 0.2% by mass or more. From the viewpoint of reducing negative electrode resistance, the Mg content in the lithium alloy is 10% by mass or less, preferably 8% by mass or less, and more preferably 7% by mass or less or 5% by mass or less. The Mg content in the lithium alloy may be, for example, 0.2% by mass or more and 10% by mass or less, or 1% by mass or more and 5% by mass or less. Note that the Mg content in the lithium alloy is the Mg content in a Li-Mg alloy or a Li-Mg-Al alloy.

[0023] From the viewpoint of suppressing deterioration of storage characteristics, the Al content in the lithium alloy (Li—Mg—Al alloy) is preferably 0.01% by mass or more (or 0.1% by mass or more) and 5% by mass or less, and more preferably 1% by mass or more and 2% by mass or less. From the same viewpoint, the total content of Mg and Al in the Li—Mg—Al alloy is preferably 0.02% by mass or more and 10% by mass or less. The molar ratio of Mg to Al (Mg / Al) may be, for example, in the range of 0.02 to 3.

[0024] The lithium alloy may contain metal elements other than Li, Mg, and Al, such as Sn, Ni, Pb, In, Na, K, and Ca.

[0025] The composition of the lithium alloy can be determined by inductively coupled plasma (ICP) emission spectroscopy or atomic absorption spectroscopy (AAS).

[0026] The lithium primary battery of the present disclosure will be described in more detail below.

[0027] [Lithium Primary Battery] (Positive Electrode) The positive electrode contains a positive electrode mixture. The positive electrode mixture contains a positive electrode active material. Examples of the positive electrode active material contained in the positive electrode include manganese dioxide. A positive electrode containing manganese dioxide exhibits a relatively high voltage and has excellent pulse discharge characteristics. Manganese dioxide may be in a mixed crystal state containing multiple types of crystalline states. The positive electrode may contain manganese oxides other than manganese dioxide. Examples of manganese oxides other than manganese dioxide include MnO, Mn ３ O ４ , Mn ２ O ３ , Mn ２ O ７ The main component of the manganese oxide contained in the positive electrode is preferably manganese dioxide.

[0028] The manganese dioxide contained in the positive electrode may be doped with a small amount of lithium. If the amount of lithium doped is small, a high capacity can be ensured. Manganese dioxide and manganese dioxide doped with a small amount of lithium are ｘ MnO ２ (0≦x≦0.05). The average composition of the manganese oxide as a whole contained in the positive electrode is Li ｘ MnO ２ (0≦x≦0.05). The Li ratio x may be 0.05 or less in the initial discharge state of the lithium primary battery. The Li ratio x generally increases as the discharge of the lithium primary battery progresses. Theoretically, the oxidation number of manganese contained in manganese dioxide is tetravalent. However, if other manganese oxides are contained in the positive electrode or if lithium is doped into manganese dioxide, the oxidation number of manganese may increase or decrease slightly from tetravalent. Therefore, Li ｘ MnO ２ In the present invention, the average oxidation state of manganese is allowed to vary slightly from tetravalent.

[0029] The positive electrode is Li ｘ MnO ２ In addition to the above, other positive electrode active materials used in lithium primary batteries can be included. Examples of other positive electrode active materials include graphite fluoride. ｘ MnO ２ The proportion of is preferably 90% by mass or more.

[0030] As the manganese dioxide, electrolytic manganese dioxide is preferably used. If necessary, electrolytic manganese dioxide may be used that has been subjected to at least one of neutralization treatment, washing treatment, and calcination treatment.

[0031] Electrolytic manganese dioxide is generally obtained by electrolysis of an aqueous manganese sulfate solution. Therefore, sulfate ions (sulfates) are inevitably contained in electrolytic manganese dioxide. A positive electrode mixture prepared using such electrolytic manganese dioxide inevitably contains sulfur atoms. When the amount of sulfate ions contained in the electrolytic manganese dioxide is 3% by mass or less, the amount of sulfur atoms contained in the positive electrode mixture is 1.6 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture.

[0032] Sulfate ions (SO ) contained in electrolytic manganese dioxide ４ ２－ The amount of sulfur dioxide (S) can be determined as follows: The mass W1 of electrolytic manganese dioxide is measured. Then, the electrolytic manganese dioxide is dissolved in an acid solution (such as hydrochloric acid) to obtain a sample solution. The amount of sulfur in the sample solution is measured using ICP atomic emission spectrometry, and the amount of sulfur is converted to the amount of sulfate ions, assuming that all of the sulfur is sulfate ions, to determine the mass W2 of sulfate ions. The amount of sulfate ions contained in the electrolytic manganese dioxide is calculated as (W2 / W1) x 100.

[0033] Furthermore, metal components other than Mn (hereinafter also referred to as "metal Me") derived from the raw materials or materials used in the cleaning process may remain in the electrolytic manganese dioxide, and the remaining metal Me may deteriorate the storage characteristics. Examples of metal Me include sodium, potassium, and calcium. In response to this, the addition of Mg to the negative electrode (lithium alloy) can suppress the deterioration of storage characteristics due to the remaining metal Me. The effect of adding Mg is obtained when the total amount of metal Me atoms (the total amount of Na, K, and Ca) contained in the positive electrode mixture is 0.5 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture. The total amount of metal Me atoms can be determined by ICP atomic emission spectroscopy in the same manner as above.

[0034] Although the detailed mechanism is unknown, it is speculated as follows. If metal Me remains in the electrolytic manganese dioxide, the metal Me contained in the positive electrode mixture dissolves into the nonaqueous electrolyte during long-term storage and precipitates on the negative electrode, and the metal Me is incorporated into the coating on the negative electrode surface. At this time, if the dispersibility of metal Me in the coating is low, Li ions are less likely to move within the coating, which may increase the negative electrode resistance. In contrast, if the negative electrode (lithium alloy) contains Mg, the dispersibility of metal Me contained in the coating is improved, and the increase in negative electrode resistance is suppressed.

[0035] It is desirable to remove as much metal Me as possible through the cleaning process, but the addition of Mg to the lithium alloy can suppress the deterioration of storage characteristics due to the remaining metal Me, and therefore, it is possible to reduce the number of steps by simplifying the cleaning process, cut cleaning costs, and reduce the environmental burden.

[0036] The ratios of sulfur atoms, sodium atoms, potassium atoms, and calcium atoms contained in the positive electrode mixture can be adjusted by adjusting the conditions of the washing treatment and the neutralization treatment. Examples of the washing treatment include at least one of a water washing treatment and an acid washing treatment. Examples of the neutralizing agent used in the neutralization treatment include inorganic bases such as ammonia and hydroxides.

[0037] By adjusting the firing conditions, the crystallinity of the manganese dioxide can be increased and the specific surface area of ​​the electrolytic manganese dioxide can be reduced. ｘ MnO ２ The BET specific surface area of ２ / g or more, 40m ２ / g or less. ｘ MnO ２ When the BET specific surface area is within the above range, self-discharge is suppressed, and the deterioration of pulse discharge characteristics after storage can be further suppressed.

[0038] Li ｘ MnO ２ The BET specific surface area may be measured by a known method, for example, by a specific surface area measuring device (for example, manufactured by Mountec Co., Ltd.) based on the BET method. ｘ MnO ２ can be used as the measurement sample.

[0039] Li determined by X-ray diffraction (XRD) ｘ MnO ２ In the X-ray diffraction pattern of １０１ Diffraction peak intensity I of the 110 plane １１０ Ratio of: I １１０ / I １０１ may be 0.25 or more and 0.75 or less. The diffraction peak of the 101 plane is observed at a diffraction angle 2θ of about 37.3°. The diffraction peak of the 110 plane is observed at a diffraction angle 2θ of about 28.7°. １１０ / I １０１ When the value of I is within the above range, self-discharge is suppressed, and the deterioration of pulse discharge characteristics after storage can be further suppressed. １１０ / I １０１ can be adjusted.

[0040] Li ｘ MnO ２ The median particle diameter of the battery may be 5 μm or more and 40 μm or less. When the median particle diameter is within the above range, self-discharge is suppressed, and deterioration of pulse discharge characteristics after storage can be further suppressed.

[0041] Li ｘ MnO ２ The median particle size of the Li particles is the median of the particle size distribution determined by, for example, quantitative laser diffraction / scattering (qLD) method. ｘ MnO ２ The measurement may be performed using, for example, an SALD-7500 nano manufactured by Shimadzu Corporation.

[0042] The positive electrode mixture may contain a binder in addition to the positive electrode active material and the sulfate. The positive electrode mixture may also contain a conductive agent.

[0043] Examples of the binder include fluororesin, rubber particles, and acrylic resin.

[0044] Examples of the conductive agent include conductive carbon materials, such as natural graphite, artificial graphite, carbon black, and carbon fiber.

[0045] The positive electrode may further include a positive electrode current collector that holds the positive electrode mixture. Examples of materials for the positive electrode current collector include stainless steel, aluminum, and titanium.

[0046] In the case of a coin-type battery, the positive electrode may be constructed by attaching a ring-shaped positive electrode current collector having an L-shaped cross section to a positive electrode mixture pellet, or by using only the positive electrode mixture pellet. The positive electrode mixture pellet can be obtained, for example, by compression-molding a wet positive electrode mixture prepared by adding an appropriate amount of water to a positive electrode active material, a binder, etc., and then drying the resulting mixture.

[0047] In the case of a cylindrical battery, a positive electrode including a sheet-shaped positive electrode current collector and a positive electrode mixture layer supported on the positive electrode current collector can be used. The sheet-shaped positive electrode current collector is preferably a perforated current collector. Examples of perforated current collectors include expanded metal, netting, and punched metal. The positive electrode mixture layer can be obtained, for example, by applying the above-mentioned wet positive electrode mixture to the surface of the sheet-shaped positive electrode current collector or by filling the positive electrode current collector with the wet positive electrode mixture, pressing it in the thickness direction, and drying it.

[0048] The positive electrode preferably comprises a porous current collector as described above and a positive electrode mixture filled in the current collector. In particular, it is preferable to use a current collector containing at least one material selected from the group consisting of SUS444, SUS430, and SUS316. By using such a current collector, it is possible to suppress side reactions with the nonaqueous electrolyte and corrosion of the current collector in a lithium primary battery, thereby suppressing an increase in internal resistance and gas generation. In particular, it is preferable to use such a current collector and LiCF4, which is typically used as a lithium salt in lithium primary batteries. ３ SO ３ and LiClO ４ When the positive electrode is combined with a non-aqueous electrolyte solution containing at least one of the above, side reactions between the current collector and the non-aqueous electrolyte solution can be more effectively suppressed. The thickness of the positive electrode is, for example, 300 μm or more and 900 μm or less.

[0049] (Negative Electrode) The negative electrode may include, for example, a foil (sheet) of a lithium alloy. The lithium alloy is formed into any shape and thickness depending on the shape, dimensions, performance specifications, etc. of the lithium primary battery.

[0050] In the case of a cylindrical battery, the negative electrode may include a negative electrode current collector (e.g., copper foil) supporting the lithium alloy, or may be a foil (sheet) lithium alloy without a negative electrode current collector. When the lithium alloy contains Mg, the relatively high strength of Mg remains at the end of discharge, allowing the negative electrode to be constructed using only a foil (sheet) lithium alloy without a negative electrode current collector. By using a lithium alloy containing Mg, breakage or partial loss of the negative electrode at the end of discharge, which occurs when the negative electrode does not include a negative electrode current collector, is suppressed. The shape of the negative electrode (lithium alloy) is maintained even at the end of discharge, and the conductivity of the entire negative electrode is ensured even without a negative electrode current collector.

[0051] In the case of coin-type batteries, a hoop-shaped lithium alloy may be punched into a disk shape and used as the negative electrode. In the case of cylindrical batteries, a sheet-shaped lithium alloy may be used as the negative electrode. The sheet may be obtained, for example, by extrusion molding. More specifically, in cylindrical batteries, a lithium alloy foil or the like having a shape with a longitudinal direction and a lateral direction is used.

[0052] (Non-aqueous Electrolyte) The non-aqueous electrolyte is prepared by dissolving a lithium salt as a solute in a non-aqueous solvent.

[0053] Examples of non-aqueous solvents include organic solvents that are commonly used in non-aqueous electrolytes for lithium primary batteries. Examples of non-aqueous solvents include ethers, esters, and carbonate esters. Examples of non-aqueous solvents that can be used include dimethyl ether, γ-butyl lactone, propylene carbonate, ethylene carbonate, and 1,2-dimethoxyethane. The non-aqueous electrolyte may contain one type of non-aqueous solvent, or may contain two or more types of non-aqueous solvents.

[0054] From the viewpoint of improving the discharge characteristics of lithium primary batteries, the nonaqueous solvent preferably contains a cyclic carbonate ester having a high boiling point and a chain ether having low viscosity even at low temperatures. The cyclic carbonate ester preferably contains at least one selected from the group consisting of propylene carbonate (PC) and ethylene carbonate (EC), with PC being particularly preferred. The chain ether preferably has a viscosity of 1 mPa·s or less at 25°C, and particularly preferably contains dimethoxyethane (DME). The viscosity of the nonaqueous solvent is measured using a Rheosens m-VROC micro-sample viscometer at 25°C and a shear rate of 10,000 (1 / s).

[0055] Examples of lithium salts include LiCF ３ SO ３ , LiClO ４ , LiBF ４ , LiPF ６ , LiRaSO ３ (Ra is a fluorinated alkyl group having 1 to 4 carbon atoms), LiFSO ３ , LiN(SO ２ Rb)(SO ２ Rc) (Rb and Rc each independently represent a fluorinated alkyl group having 1 to 4 carbon atoms), LiN(FSO ２ ) ２ The lithium salts may be used alone or in combination of two or more.

[0056] The concentration of lithium ions contained in the nonaqueous electrolyte (total concentration of lithium salts) may be, for example, 0.2 mol / L or more and 2.0 mol / L or less, or 0.3 mol / L or more and 1.5 mol / L or less.

[0057] The non-aqueous electrolyte may contain additives as needed. Examples of such additives include phthalimide, N-substituted phthalimide compounds, dimethyl phthalate, phthalate ester compounds, propane sultone, and vinylene carbonate. The total concentration of such additives contained in the non-aqueous electrolyte is, for example, 0.003 to 5 mol / L.

[0058] (Separator) A lithium primary battery usually includes a separator interposed between the positive electrode and the negative electrode. As the separator, a porous sheet formed of an insulating material that is resistant to the internal environment of a lithium primary battery may be used. Specific examples include a synthetic resin nonwoven fabric, a synthetic resin microporous membrane, or a laminate thereof.

[0059] Examples of synthetic resins used for nonwoven fabrics include polypropylene, polyphenylene sulfide, and polybutylene terephthalate. Examples of synthetic resins used for microporous membranes include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers. The microporous membrane may contain inorganic particles as needed.

[0060] The thickness of the separator is, for example, 5 μm or more and 100 μm or less.

[0061] The structure of the lithium primary battery is not particularly limited. The lithium primary battery may be a coin battery having a stacked electrode group formed by stacking a disc-shaped positive electrode and a disc-shaped negative electrode with a separator interposed therebetween. Alternatively, the lithium primary battery may be a cylindrical battery having a wound electrode group formed by spirally winding a strip-shaped positive electrode and a strip-shaped negative electrode with a separator interposed therebetween.

[0062] 1 shows a partially cross-sectional front view of a cylindrical lithium primary battery according to one embodiment of the present disclosure. In the lithium primary battery 10, an electrode group, in which a positive electrode 1 and a negative electrode 2 are wound with a separator 3 interposed therebetween, is housed in a battery case 9 together with a nonaqueous electrolyte (not shown). A sealing plate 8 is attached to the opening of the battery case 9. A positive electrode lead 4 connected to a current collector 1a of the positive electrode 1 is connected to the sealing plate 8. A negative electrode lead 5 connected to the negative electrode 2 is connected to the case 9. In addition, an upper insulating plate 6 and a lower insulating plate 7 are arranged at the top and bottom of the electrode group, respectively, to prevent internal short circuits.

[0063] <<Supplementary Note>> The above embodiments disclose the following techniques: (Technology 1) A battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte solution, wherein the positive electrode contains a positive electrode mixture, and the positive electrode mixture contains Li ｘ MnO ２ (Technology 2) A lithium primary battery according to Technology 1, wherein the alloy contains aluminum, and the total content of the magnesium and the magnesium in the alloy is 0.02% by mass or more and 10% by mass or less. (Technology 3) A lithium primary battery according to Technology 1, wherein the alloy contains aluminum, and the total content of the magnesium and the aluminum in the alloy is 0.02% by mass or more and 10% by mass or less. (Technology 4) A lithium primary battery according to Technology 2, wherein the total content of the magnesium and the aluminum in the alloy is 0.02% by mass or more and 10% by mass or less. (Technology 5) A lithium primary battery according to Technology 1, wherein the total content of the magnesium and the aluminum in the alloy is 0.02% by mass or more and 10% by mass or less. (Technology 6) A lithium primary battery according to Technology 2, wherein the total content of the magnesium and the aluminum in the alloy is 0.02% by mass or more and 10% by mass or less. ｘ MnO ２ In the X-ray diffraction pattern, the diffraction peak intensity I of the (101) plane １０１ Diffraction peak intensity I of the (110) plane １１０ Ratio of: I １１０ / I １０１ The lithium primary battery according to Technology 1 or 2, wherein Li is 0.25 or more and 0.75 or less. ｘ MnO ２ The lithium primary battery according to any one of the first to third aspects, wherein the median particle diameter of Li is 5 μm or more and 40 μm or less.ｘ MnO ２ The BET specific surface area of ２ / g or more, 40m ２ / g or less.

[0064] [Examples] Hereinafter, the present disclosure will be specifically described based on examples and comparative examples, but the present disclosure is not limited to the following examples.

[0065] <Batteries A1 to A16, Batteries B1 to B9> (Preparation of Positive Electrodes) For the positive electrodes, 100 parts by mass of the positive electrode active material was mixed with 3 parts by mass of Ketjen Black as a conductive agent, 5 parts by mass of polytetrafluoroethylene as a binder, and an appropriate amount of pure water to prepare a wet positive electrode mixture. Electrolytic manganese dioxide baked at 420°C for 8 hours was used as the positive electrode active material.

[0066] Next, the positive electrode mixture was filled into a positive electrode current collector made of expanded metal of stainless steel (SUS444) with a thickness of 0.4 mm to prepare a positive electrode precursor. The positive electrode precursor was then dried, rolled to a thickness of 0.5 mm using a roll press, and cut to a predetermined size to obtain a positive electrode. Subsequently, a portion of the filled positive electrode mixture was peeled off, and one end of a stainless steel positive electrode lead was resistance-welded to the exposed portion of the positive electrode current collector.

[0067] (Preparation of Negative Electrode) A lithium metal foil or lithium alloy foil (thickness: 200 μm) was cut to a predetermined size to obtain a negative electrode. One end of a nickel negative electrode lead was connected to a predetermined location on the negative electrode by ultrasonic welding. The elements contained in the lithium alloy foil other than Li were Mg and / or Al. The Mg content and Al content in the lithium alloy foil were the values ​​shown in Tables 1 and 2. In Tables 1 and 2, a "-" in the Mg content (or Al content) column means that the Mg content (or Al content) was below the detection limit in composition analysis (such as ICP atomic emission spectroscopy).

[0068] (Preparation of Electrode Assembly) An electrode assembly was prepared by winding a positive electrode and a negative electrode with a separator interposed therebetween, the separator being a microporous polypropylene film having a thickness of 25 μm.

[0069] (Preparation of non-aqueous electrolyte) Propylene carbonate (PC), ethylene carbonate (EC), and 1,2-dimethoxyethane (DME) were mixed in a volume ratio of 4:2:4 to obtain a non-aqueous solvent. ３ SO ３ was dissolved in a concentration of 0.5 mol / L to prepare a non-aqueous electrolyte solution.

[0070] (Assembly of Lithium Primary Battery) The electrode group was housed in a cylindrical battery case that also served as a negative electrode terminal. An iron case (outer diameter 17 mm, height 45.5 mm) was used as the battery case. Next, a nonaqueous electrolyte was poured into the battery case, and the opening of the battery case was closed with a metal sealing plate that also served as a positive electrode terminal. The other end of the positive electrode lead was connected to the sealing plate, and the other end of the negative electrode lead was connected to the inner bottom surface of the battery case. In this way, a cylindrical lithium primary battery was produced. The battery immediately after assembly was discharged at 2.4 A for 2 minutes and then aged for 7 days in an atmosphere at 45°C. Note that the positive electrode active material after aging was Li ｘ MnO ２ The x value, which indicates the amount of lithium doped, was in the range of 0<x≦0.05. Batteries A1 to A16 in Table 1 are examples, and batteries B1 to B9 in Table 2 are comparative examples.

[0071] The amount of sulfate contained in the electrolytic manganese dioxide was adjusted by adjusting the conditions of the cleaning and neutralization treatments during the production of electrolytic manganese dioxide. As a result, the amount of sulfate ions (mass %) contained in the electrolytic manganese dioxide and the amount of sulfur atoms (parts by mass) contained in the positive electrode mixture, determined by the methods described above, were set to the values ​​shown in Tables 1 and 2. Note that the "amount of sulfur atoms contained in the positive electrode mixture" in the tables is the amount (parts by mass) per 100 parts by mass of manganese atoms contained in the positive electrode mixture.

[0072] Furthermore, metal Me (at least one of Na, K, and Ca) may remain in the electrolytic manganese dioxide, and the total amount of metal Me atoms contained in the positive electrode mixture was 0.5 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture.

[0073] Li contained in the positive electrode mixture ｘ MnO２ has a median particle size of 21 to 23 μm and a BET specific surface area of ​​14 to 15 m ２ / g, and I １１０ / I １０１ The peak intensity ratio was 0.58.

[0074] [Evaluation] (Internal Resistance of Battery After Storage) The battery after the aging treatment was stored for 4 months at 70° C. The internal resistance of the battery after storage was measured in an environment of 20° C.

[0075] (Low-Temperature Pulse Discharge Test of Stored Batteries) The aging-treated batteries were stored for 4 months at 70° C. The stored batteries were left to stand in an environment of −30° C. for 2 hours, and then pulse-discharged at 300 mA for 1 second in an environment of −30° C. The minimum voltage at this time was determined as the pulse discharge voltage.

[0076] The evaluation results are shown in Tables 1 and 2. In Tables 1 and 2, the internal resistance is expressed as a relative value when the internal resistance of Battery B3 is set to 100. The pulse discharge voltage is expressed as a relative value when the pulse discharge voltage of Battery B3 is set to 100.

[0077]

[0078]

[0079] Batteries A1 to A16, which had a negative electrode containing a lithium alloy with a Mg content of 0.01 to 10% by mass and a positive electrode containing a positive electrode mixture with a sulfur content of 1.6 parts by mass or less, exhibited excellent storage characteristics. Batteries B1 to B7, which had a negative electrode containing a lithium alloy or lithium metal with a Mg content outside the range of 0.01 to 10% by mass and / or a positive electrode containing a positive electrode mixture with a sulfur content greater than 1.6 parts by mass, exhibited poor storage characteristics. Batteries B8 and B9, which had a lithium alloy with a Li content of 88% by mass or less, exhibited poor storage characteristics.

[0080] In Battery B5, which used Li-Al foil (Al content: 1% by mass), the increase in pulse discharge voltage after storage was very small (100 → 102) compared to Battery B3, which used Li foil. On the other hand, in Battery A8, which used Li-Mg foil (Mg content: 1% by mass), the pulse discharge voltage after storage increased to 116, and in Battery A14, which used Li-Mg-Al foil (Mg content: 1% by mass, Al content: 1% by mass), the pulse discharge voltage after storage was 124, a further significant increase compared to Battery A8. This shows that the effect of adding Al to improve storage characteristics is significantly obtained when the lithium alloy contains Mg.

[0081] Batteries A17 to A22: In the firing of electrolytic manganese dioxide, the firing temperature is adjusted to 350 to 470°C and the firing time is adjusted to 2 to 8 hours. １１０ / I １０１ Batteries A17 to A22 were fabricated and evaluated in the same manner as Battery A3, except that the peak intensity ratios were set to the values ​​shown in Table 3. The evaluation results are shown in Table 3. Table 3 also shows the results for Battery A3. In Table 3, Batteries A17 to A22 are examples.

[0082]

[0083] All batteries showed excellent storage characteristics. １１０ / I １０１ The storage characteristics of the batteries A3 and A17 to A20, in which the peak intensity ratio was 0.25 to 0.75, were further improved.

[0084] The lithium primary battery of the present disclosure is suitable for use, for example, as a main power source or memory backup power source for various meters (for example, smart meters for electricity, water, gas, etc.).

[0085] While the present invention has been described in terms of presently preferred embodiments, such disclosure is not to be interpreted as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. It is therefore intended that the appended claims be interpreted to cover all changes and modifications that do not depart from the true spirit and scope of the invention.

[0086] REFERENCE SIGNS LIST 1 positive electrode 1a positive electrode current collector 2 negative electrode 3 separator 4 positive electrode lead 5 negative electrode lead 6 upper insulating plate 7 lower insulating plate 8 sealing plate 9 battery case 10 lithium primary battery

Claims

1. A battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, the positive electrode including a positive electrode mixture, the positive electrode mixture including Li ｘ MnO ２ (0≦x≦0.05) and a sulfate, wherein the amount of sulfur atoms contained in the positive electrode mixture is 1.6 parts by mass or less per 100 parts by mass of manganese atoms contained in the positive electrode mixture, the negative electrode includes an alloy containing lithium and magnesium, the content of the lithium in the alloy is more than 88% by mass, and the content of the magnesium in the alloy is 0.01% by mass or more and 10% by mass or less.

2. The lithium primary battery according to claim 1, wherein the alloy contains aluminum, and the total content of the magnesium and the aluminum in the alloy is 0.02 mass % or more and 10 mass % or less.

3. Li determined by X-ray diffraction method ｘ MnO ２ In the X-ray diffraction pattern, the diffraction peak intensity I of the (101) plane １０１ Diffraction peak intensity I of the (110) plane １１０ Ratio of: I １１０ / I １０１ The lithium primary battery according to claim 1 , wherein is 0.25 or more and 0.75 or less.

4. Li ｘ MnO ２ 2. The lithium primary battery according to claim 1, wherein the median particle size of the particles is 5 μm or more and 40 μm or less.

5. Li ｘ MnO ２ The BET specific surface area of ２ / g or more, 40m ２ 2. The lithium primary battery according to claim 1, wherein the capacitance is 0.1 μm or less.

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