JP4859277B2 - Non-aqueous secondary battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-aqueous secondary battery, and more particularly to a non-aqueous secondary battery for a power storage system.
[0002]
[Prior art]
In recent years, from the viewpoint of effective use of energy aiming at resource saving and global environmental problems, attention has been focused on home-use distributed storage systems for the storage of late-night power storage and solar power generation, storage systems for electric vehicles, etc. Collecting. For example, Japanese Patent Laid-Open No. 6-86463 proposes a total system that combines electricity, gas cogeneration, fuel cells, storage batteries, and the like supplied from a power plant as a system that can supply energy to energy consumers under optimum conditions. ing. A secondary battery used in such a power storage system requires a large battery having a large capacity, unlike a small secondary battery for portable equipment having an energy capacity of 10 Wh or less. For this reason, in the above power storage system, a plurality of secondary batteries are usually stacked in series and used as an assembled battery having a voltage of 50 to 400 V, for example, and in most cases, lead batteries are used.
[0003]
On the other hand, in the field of small secondary batteries for portable devices, the development of nickel-metal hydride batteries and lithium secondary batteries as new batteries has progressed to meet the needs for small size and high capacity, and has a volumetric energy density of 180 Wh / l or more. Batteries are commercially available. In particular, a lithium ion battery has a possibility of a volume energy density exceeding 350 Wh / l, and reliability such as safety and cycle characteristics is superior to a lithium secondary battery using metallic lithium as a negative electrode. , Has dramatically expanded its market.
[0004]
In response, in the field of large-scale batteries for power storage systems, lithium-ion batteries are targeted as candidates for high-energy density batteries, and development is actively underway by the Lithium Battery Power Storage Technology Research Association (LIBES) and others. .
[0005]
The energy capacity of these large-sized lithium ion batteries is about 100 Wh to 400 Wh, and the volume energy density is 200 to 300 Wh / l, the same level as a small secondary battery for portable devices. The shape is typically a cylindrical shape having a diameter of 50 mm to 70 mm, a length of 250 mm to 450 mm, and a flat prismatic shape such as a square or oblong square having a thickness of 35 mm to 50 mm.
[0006]
However, although these large lithium ion batteries provide high energy density, the battery design is an extension of the small battery for portable devices, so that the diameter or thickness of the large lithium ion batteries is more than three times that of the small batteries for portable devices. The battery has a square shape. In this case, heat is likely to be accumulated inside the battery due to Joule heat generation due to the internal resistance of the battery during charging and discharging, or internal heat generation of the battery due to change in entropy of the active material due to the entry and exit of lithium ions. For this reason, the temperature difference between the temperature inside the battery and the vicinity of the battery surface is large, and the internal resistance differs accordingly. As a result, variations in charge amount and voltage are likely to occur. In addition, since this type of battery is used as a plurality of assembled batteries, the ease of heat storage differs depending on the installation position of the batteries in the system, resulting in variations among the batteries, and accurate control of the entire assembled battery is possible. It becomes difficult. In addition, because of insufficient heat dissipation during high-rate charging / discharging, etc., the battery temperature rises, leaving the battery unfavorable, resulting in a decrease in life due to decomposition of the electrolyte, and thermal runaway of the battery. Problems such as induction of reliability, particularly safety, remained.
[0007]
In order to solve the above problem, W099 / 60652 discloses a flat non-aqueous secondary battery in which a non-aqueous electrolyte containing a positive electrode, a negative electrode, a separator, and a lithium salt is contained in a battery container, An aqueous secondary battery has a flat shape with a thickness of less than 12 mm, a non-aqueous secondary battery having an energy capacity of 30 Wh or more and a volume energy density of 180 Wh / l or more is disclosed. The battery proposes to solve the problems of reliability and safety caused by the heat storage, which is a barrier to practical use, due to the unique battery shape (flat shape).
[0008]
[Problems to be solved by the invention]
By the way, flat non-aqueous secondary batteries having a thickness of less than 12 mm are mainly applied to the field of large batteries for power storage systems. However, in practical use, in addition to ensuring safety, manufacturing costs can be reduced. Is an important point. As an example of manufacturing these batteries, as shown in FIG. 5, a bottom container having an upper lid and a flange portion is dropped and welded by laser welding at a point A shown in FIG. A bottom container having a flange portion can be manufactured by drawing, but in order to ensure the maximum effective battery capacity with the same outer peripheral shape and thickness, the bottom container has a side plate portion and a bottom plate portion. In order to set the angle θ to 90 °, it is necessary to devise such as transfer molding in which a plurality of molds are used to gradually squeeze the processed product, and thus there is a problem in that the manufacturing cost increases.
[0009]
The object of the present invention is to achieve the maximum battery effective internal volume possible with the same outer peripheral shape and thickness even by drawing processing that can be molded at low cost in a non-aqueous secondary battery having a flat shape with a thickness of less than 12 mm. An object of the present invention is to provide a non-aqueous secondary battery capable of securing a near effective battery capacity.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention accommodates a nonaqueous electrolyte containing a positive electrode, a negative electrode, a separator, and a lithium salt in a battery container, has a flat shape with a thickness of less than 12 mm, an energy capacity of 30 Wh or more and A nonaqueous secondary battery having a volumetric energy density of 180 Wh / l or more, wherein the battery container includes a lid and a bottom container formed by press working, and the thickness of the battery container is 0.2 mm or more and 1 mm. The non-aqueous secondary battery is characterized in that the angle formed by the side plate portion and the bottom plate portion of the bottom container is set to be more than 90.5 ° and less than 95 °. is there.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a nonaqueous secondary battery according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a plan view and a side view of a flat rectangular (note type) non-aqueous secondary battery for an electricity storage system according to an embodiment of the present invention, and FIG. 2 is housed inside the battery shown in FIG. It is a side view which shows the structure of an electrode laminated body.
[0012]
As shown in FIGS. 1 and 2, the non-aqueous secondary battery according to the present embodiment includes a battery container including a lid 1 and a bottom container 2 to which terminals are attached, and a plurality of batteries accommodated in the battery container. Electrode laminate including the positive electrode 101 a, the negative electrodes 101 b and 101 c, and the separator 104. In the case of a flat type non-aqueous secondary battery as in the present embodiment, the positive electrode 101a and the negative electrode 101b (or the negative electrode 101c disposed on both outer sides of the laminate) have separators 104, for example, as shown in FIG. However, the present invention is not particularly limited to this arrangement, and the number of layers and the like can be variously changed according to the required capacity and the like. The shape of the non-aqueous secondary battery shown in FIG. 1 is, for example, 300 mm long × 210 mm wide × 6 mm thick. The lithium secondary battery uses LiMn ₂ O _{4 for} the positive electrode 101a and a carbon material for the negative electrodes 101b and 101c. In this case, for example, it can be used for a power storage system.
[0013]
The positive electrode current collector 105 a of each positive electrode 101 a is electrically connected to the positive electrode terminal 3. Similarly, the negative electrode current collector 105 b of each negative electrode 101 b, 101 c is electrically connected to the negative electrode terminal 4. The positive electrode terminal 3 and the negative electrode terminal 4 are attached in a state insulated from the battery container, that is, the lid 1.
[0014]
The lid 1 and the bottom container 2 are welded to the bottom container 2 by melting the point A shown in the enlarged view in FIG. The lid 1 is provided with an electrolytic solution injection port 5, and after the electrolytic solution injection, the lid 1 is sealed using, for example, a sealing film 6 made of an aluminum-modified polypropylene laminate film. The final sealing step is preferably performed after at least one charging operation. The pressure in the battery container after the final sealing step with the sealing film 6 is preferably less than atmospheric pressure, more preferably 8.66 × 10 ⁴ Pa (650 Torr) or less, and particularly preferably 7.33 × 10 ⁴ Pa. (550 Torr) or less. That is, when the internal pressure is equal to or higher than the atmospheric pressure, the battery is likely to be larger than the designed thickness, or the variation in the battery thickness is likely to increase, and further, the internal resistance and capacity of the battery are likely to vary. This pressure is determined in consideration of the separator to be used, the type of electrolytic solution, the material and thickness of the battery container, the shape of the battery, and the like.
[0015]
The positive electrode active material used for the positive electrode 101a is not particularly limited as long as it is a lithium-based positive electrode material, and lithium composite cobalt oxide, lithium composite nickel oxide, lithium composite manganese oxide, or a mixture thereof, A system in which one or more different metal elements are added to these composite oxides can be used, and a high voltage and high capacity battery can be obtained, which is preferable. Further, in the case of emphasizing safety, which is the highest priority issue in practical use of a large lithium secondary battery, manganese oxide having a high thermal decomposition temperature is preferable. As this manganese oxide, a lithium composite manganese oxide typified by LiMn ₂ O ₄ , a system in which one or more different metal elements are added to these composite oxides, and a lithium in which lithium is made in excess of the stoichiometric ratio _{1 + x Mn 2-y O} 4 and the like. In particular, the present invention has a great effect when a positive electrode mainly composed of the manganese oxide is used.
[0016]
The negative electrode active material used for the negative electrodes 101b and 101c is not particularly limited as long as it is a lithium-based negative electrode material, and is a material capable of doping and dedoping lithium, such as safety and reliability such as cycle life. Is preferable. Examples of materials that can be doped and dedoped with lithium include graphite-based materials, carbon-based materials, tin oxide-based, silicon oxide-based metal oxides, and polyacene, which are used as negative electrode materials for known lithium ion batteries. Examples thereof include conductive polymers represented by organic organic semiconductors.
[0017]
Although the structure of the separator 104 is not particularly limited, a single-layer or multi-layer separator can be used, and at least one sheet is preferably a nonwoven fabric. In this case, cycle characteristics are improved. The material of the separator 104 is not particularly limited, and examples thereof include polyolefins such as polyethylene and polypropylene, polyamides, kraft paper, glass, cellulosic materials, and the like, depending on the heat resistance and safety design of the battery. It is determined appropriately.
[0018]
As the electrolyte of the non-aqueous secondary battery of this embodiment, a non-aqueous electrolyte containing a known lithium salt can be used, which is appropriately determined according to the use conditions such as the positive electrode material, the negative electrode material, and the charging voltage, and more specifically. Includes lithium salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyrolactone, methyl acetate, methyl formate, or two or more of these And those dissolved in an organic solvent such as a mixed solvent. Further, the concentration of the electrolytic solution is not particularly limited, but generally 0.5 mol / l to 2 mol / l is practical, and naturally the electrolytic solution has a water content of 100 ppm or less. It is preferable to use it. In addition, the non-aqueous electrolyte used in this specification means a concept including a non-aqueous electrolyte solution and an organic electrolyte solution, and also refers to a concept including a gel-like or solid electrolyte.
[0019]
The non-aqueous secondary battery configured as described above can be used for a household power storage system (night power storage, cogeneration, solar power generation, etc.), a power storage system such as an electric vehicle, and the like. It can have an energy density. In this case, the energy capacity is preferably 30 Wh or more, more preferably 50 Wh or more, and the energy density is preferably 180 Wh / l or more, more preferably 200 Wh / l. When the energy capacity is less than 30 Wh or when the volumetric energy density is less than 180 Wh / l, the capacity is small for use in the power storage system, and it is necessary to increase the number of series-parallel batteries to obtain sufficient system capacity. In addition, it is not preferable for a power storage system because a compact design becomes difficult.
[0020]
The nonaqueous secondary battery of the present embodiment has a flat shape, and the thickness thereof is less than 12 mm, more preferably less than 10 mm. As for the lower limit of the thickness, since it is necessary to attach a terminal to the lid 1, 5 mm or more is practical. When the thickness of the battery is 12 mm or more, it becomes difficult to sufficiently dissipate the heat generated inside the battery to the outside, or the temperature difference between the inside of the battery and the vicinity of the battery surface increases, resulting in different internal resistances. The variation in the amount of charge and voltage in the battery increases. The specific thickness is appropriately determined according to the battery capacity and the energy density, but it is preferable to design with the maximum thickness that provides the expected heat dissipation characteristics.
[0021]
In addition, as the shape of the non-aqueous secondary battery of the present embodiment, for example, the flat front and back surfaces can be various shapes such as a square, a circle, an oval, and the rectangular shape is generally rectangular. However, it may be a polygon such as a triangle or a hexagon. Furthermore, it can also be made into cylindrical shapes, such as a thin cylinder. In the case of a cylinder, the thickness of the cylinder is the thickness referred to here.
[0022]
The material used for the lid 1 and the bottom container 2 serving as the battery container is appropriately selected depending on the use and shape of the battery, and is not particularly limited, and iron, stainless steel, aluminum, etc. are generally used, and from the viewpoint of cost. Is also practical. Moreover, the plate | board thickness of a battery container is also determined suitably by the use of a battery, a shape, or the material of a battery bottom container, and is not specifically limited. Preferably, the thickness of 80% or more portions of the cell surface area (thickness of the top wide area portion constituting the battery container) is 0.2mm or more. If the plate thickness is less than 0.2 mm, it is not desirable because the strength required for manufacturing the battery cannot be obtained. From this viewpoint, it is more preferably 0.3 mm or more. The plate thickness of the same part is desirably 1 mm or less. When the plate thickness exceeds 1 mm, the force for pressing the electrode surface increases, but it is not desirable because the internal capacity of the battery is reduced and sufficient capacity cannot be obtained, or the weight is increased. Preferably it is 0.7 mm or less.
[0023]
In the present invention, the angle formed between the side surface and the bottom surface of the battery container is more than 90 ° and less than 100 °. In the case of the manufacturing example described above, the angle formed by the side surface and the bottom surface of the battery container is determined by the bottom container 2, and is the angle formed by the line α and the line β in FIG.
[0024]
The angle between the side surface and the bottom surface of the battery case is appropriately determined depending on the size of the battery case, the hardness of the material, the Young's modulus, and the like. , Battery capacity decreases. In addition, when the angle is 90 °, it is necessary to devise transfer molding (processing that gradually narrows down with a plurality of molds) and the like, which increases the manufacturing cost.
[0025]
In the present invention, the angle θ formed by the side plate portion 2a and the bottom plate portion 2b of the battery container is set to be more than 90 ° and less than 100 °. Thereby, it is possible to obtain the bottom container 2 by one or several drawing processes using the same mold. In addition, since the non-aqueous secondary battery of the present invention has a flat shape with a thickness of 12 mm or less, if the angle θ formed between the side plate portion 2a and the bottom plate portion 2b of the battery container is more than 90 ° and less than 100 °, the battery The effective internal volume (portion surrounded by a two-dot chain line in FIG. 3) is close to the maximum battery effective internal volume possible with a predetermined outer peripheral shape and thickness. From these viewpoints, the angle θ formed between the side plate portion 2a and the bottom plate portion 2b of the battery container is more preferably 90.5 ° to 95 °, and further preferably 91 ° to 92 °. The drawing process is preferably performed once from the viewpoint of the labor and cost of processing, but it is preferable to perform the drawing process twice or more from the viewpoint of processing accuracy and strength. From this viewpoint, it is performed three times or more. Is more desirable.
[0026]
The plate thickness of the battery container is appropriately determined depending on the use of the battery or the material of the battery bottom container, and is not particularly limited. However, preferably, the plate thickness of the portion of the battery surface area of 80% or more (constituting the battery container) The plate thickness of the widest area) is 0.2 mm or more. If the plate thickness is less than 0.2 mm, the strength required for battery production is not obtained, which is not desirable. From this viewpoint, it is more preferably 0.3 mm or more, and further preferably 0.4 mm or more. . The plate thickness of the same part is desirably 1 mm or less. When the plate thickness exceeds 1 mm, the force for pressing the electrode surface increases, but it is not desirable because the internal capacity of the battery is reduced and sufficient capacity cannot be obtained, or the weight is increased. Preferably it is 0.7 mm or less.
[0027]
As described above, by designing the thickness of the non-aqueous secondary battery to be less than 12 mm, for example, when the battery has a large capacity of 30 Wh or more and a high energy density of 180 Wh / l, a high rate charge / discharge is performed. Even when broken, the battery temperature rise is small and excellent heat dissipation characteristics can be realized. Accordingly, the heat storage of the battery due to internal heat generation is reduced, and as a result, thermal runaway of the battery can be suppressed, and a non-aqueous secondary battery excellent in reliability and safety can be provided.
[0028]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0029]
(1) 100 parts by weight of LiMn ₂ O ₄ , 8 parts by weight of acetylene black and 3 parts by weight of polyvinylidene fluoride (PVDF) were mixed with 100 parts by weight of N-methylpyrrolidone (NMP) to obtain a positive electrode mixture slurry. The slurry was applied to both sides of a 20 μm thick aluminum foil serving as a current collector, dried, and then pressed to obtain a positive electrode. (A) of FIG. 4 is explanatory drawing of a positive electrode. In this example, the application area (W1 × W2) of the positive electrode 101a is 277.5 × 202 mm ² , and is applied to both surfaces of a 20 μm current collector with a thickness of 110 μm. As a result, the electrode thickness t is 240 μm. Moreover, the positive electrode current collection piece 106a with which the electrode is not apply | coated is provided in the short side of an electrode, and the hole of (phi) 3 is made in the center.
[0030]
(2) 100 parts by weight of graphitized mesocarbon microbeads (MCMB, manufactured by Osaka Gas Chemical Co., No. 6-28) and 10 parts by weight of PVDF were mixed with 90 parts by weight of NMP to obtain a negative electrode mixture slurry. The slurry was applied to both sides of a 14 μm thick copper foil serving as a current collector, dried, and then pressed to obtain a negative electrode. FIG. 4B is an explanatory diagram of the negative electrode. The application area (W1 × W2) of the negative electrode 101b is 282 × 205 mm ² , and is applied to both surfaces of a 14 μm current collector with a thickness of 90 μm.
As a result, the electrode thickness t is 194 μm. Further, a negative electrode current collecting piece 106b to which no electrode is applied is provided on the short side of the electrode, and a 3 mm hole is formed in the center thereof. Further, a single-sided electrode having a thickness of 104 μm was prepared by the same method except that the coating was applied to only one side. The single-sided electrode is arranged on the outer side in the electrode laminate of item (3) (101c in FIG. 2).
[0031]
(3) As shown in FIG. 2, 8 sheets of positive electrodes and 9 sheets of negative electrodes (2 sheets on the inner side) obtained in the above item (1) were combined with separator A (rayon system, basis weight 12.6 g / m ² ) and separator B. (Polyethylene microporous membrane; weight per unit area: 13.3 g / m ² ) are laminated alternately via separators 104, and further, separator B is provided on the outer side of outer negative electrode 101c for insulation from the battery container. Arranged to create an electrode stack. The separator 104 was arranged so that the separator A104a was on the positive electrode side and the separator B104b was on the negative electrode side.
[0032]
(4) As shown in FIG. 3, the bottom container 2 was made of a SUS304 thin plate having a thickness of 0.5 mm, and the lid 1 was made of a SUS304 thin plate having a thickness of 0.5 mm. In the bottom container 2, drawing was performed in three times using one type of mold, and the angle θ formed by the bottom plate portion 2 b and the side plate portion 2 a was 92 °. Next, as shown in FIG. 3, the positive electrode terminal 3 made of aluminum and the negative electrode terminal 4 made of copper were attached to the lid 1. The positive and negative terminals 3 and 4 were insulated and fixed to the lid 1 with polypropylene gaskets 1a and 1b.
[0033]
(5) Each positive electrode current collecting piece 106 a and each negative electrode current collecting piece 106 b of the electrode laminate prepared in the above item (3) were connected to the negative electrode terminal 4. After inserting this electrode laminated body into the bottom container 2, the position shown to A of FIG. 1 was laser-welded over the perimeter. Thereafter, a solution in which LiPF ₆ was dissolved at a concentration of 1 mol / l was poured into a solvent in which ethylene carbonate and diethyl carbonate were mixed at a 1: 1 weight ratio as an electrolytic solution from the pouring port 5. Next, under the atmospheric pressure, the liquid injection port 5 was once sealed using a temporary fixing bolt.
[0034]
(6) This battery is charged to 4.2 V with a current of 5 A, and then subjected to constant current and constant voltage charging for 12 hours to apply a constant voltage of 4.2 V, and then discharged to 2.5 V with a constant current of 5 A. did.
[0035]
(7) Remove the temporary fixing bolt attached to the battery, and again from a 0.08 mm thick aluminum foil-modified polypropylene laminate film punched to 12 mmφ under reduced pressure of 4.00 × 10 ⁴ Pa (300 Torr) The sealing film 6 is thermally fused under the conditions of a temperature of 250 to 350 ° C., a pressure of 98.1 to 294 kPa (1 to 3 kg / cm ² ), and a pressurization time of 5 to 10 seconds, whereby the liquid inlet 5 is finally formed. Sealing was performed to obtain a flat notebook battery having a thickness of 6 mm.
[0036]
The battery is charged to 4.2V with a current of 5A, and then a constant current / constant voltage charge is applied for 12 hours by applying a constant voltage of 4.2V, followed by discharging to 2.5V with a constant current of 5A. It was confirmed. The discharge capacity was 29.5 Ah. (Capacity: 109 Wh, volumetric energy density: 288 Wh / l)
[0037]
[Comparative example]
In Example 1, using one type of mold to make the angle formed by the bottom plate portion 2b and the side plate portion 2a of the bottom container 2 to 90 °, several times of drawing processing were attempted, but the angle was 90. In the case of 5 ° or less, fine cracks were generated in the bottom container 2 at the point B in FIG. As a result, it was found that defective products would occur if the angle was set to 90 ° by drawing.
[0038]
【Effect of the invention】
According to the non-aqueous secondary battery of the present invention, the angle formed between the side plate portion and the bottom plate portion of the bottom container of the battery container is set to be more than 90 ° and less than 100 °. A battery effective internal volume close to the maximum battery effective internal volume possible by the thickness can be secured, and a sufficient battery capacity can be secured. Moreover, since it is not necessary to make the angle which a side plate part and a baseplate part make into 90 degrees, the processing method which manufacture cost becomes cheap can be employ | adopted.
[Brief description of the drawings]
1A and 1B are a plan view and a side view of a nonaqueous secondary battery for a power storage system according to an embodiment of the present invention.
2 is a side view showing a configuration of an electrode laminate housed in the battery shown in FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing a state in which a top cover and a bottom container of the battery shown in FIG. 1 are separated.
4 is a plan view of a positive electrode, a negative electrode, and a separator that constitute the laminate shown in FIG. 2. FIG.
5A and 5B are a plan view and a side view of a conventional non-aqueous secondary battery for a power storage system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Top lid 2 Bottom container 2a Side plate part 2b of bottom container Bottom plate part θ of bottom container 3 Angle formed by side plate part and bottom plate part of bottom container 3 Positive electrode external terminal 4 Negative electrode external terminal 5 Injection port 6 Sealing films 7, 8 Gasket 101a Positive electrode (Both sides)
101b Negative electrode (both sides)
101c Negative electrode (single side)
104 Separator 105a Positive electrode current collector 105b Negative electrode current collector 106a Positive electrode current collector piece 106b Negative electrode current collector piece

Claims (8)

A non-aqueous electrolyte containing a positive electrode, a negative electrode, a separator, and a lithium salt is accommodated in a battery container, has a flat shape with a thickness of less than 12 mm, an energy capacity of 30 Wh or more, and a volume energy density of 180 Wh / l or more. A secondary battery,
The battery container includes a lid and a bottom container formed by pressing, and the plate thickness of the battery container is 0.2 mm or more and 1 mm or less, and the angle formed between the side plate portion and the bottom plate portion of the bottom container is: It is set so that it may exceed 90.5 degrees and may be less than 95 degrees, The non-aqueous secondary battery characterized by the above-mentioned. The battery case is flat rectangular, nonaqueous secondary battery according to claim 1, wherein the thickness of the battery container is less than 12 mm.   3. The non-aqueous secondary battery according to claim 1, wherein the pressure in the battery container is less than atmospheric pressure.   After charging at least once, the pressure of the battery container when sealing the electrolyte injection port provided on the lid of the battery container in a state where the pressure in the battery container is less than atmospheric pressure is the atmospheric pressure. The non-aqueous secondary battery according to any one of claims 1 to 3, wherein the non-aqueous secondary battery is set to be lower than the lower limit.   The non-aqueous secondary battery according to any one of claims 1 to 4, wherein the pressure in the battery container is 650 Torr or less.   The non-aqueous secondary battery according to claim 1, wherein the negative electrode includes a material capable of doping and dedoping lithium.   The non-aqueous secondary battery according to claim 1, wherein the positive electrode contains a manganese oxide.   The nonaqueous secondary battery according to any one of claims 1 to 7, wherein a shape of both front and back surfaces of the battery container is a rectangle.

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