JP4009802B2 - Non-aqueous secondary battery and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-aqueous secondary battery and a manufacturing method thereof, and more particularly to a non-aqueous secondary battery for a power storage system and a manufacturing method thereof.
[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]
As for a thin lithium secondary battery, for example, a film battery in which a film having a thickness of 1 mm or less obtained by laminating metal and plastic is accommodated in a thin exterior (Japanese Patent Laid-Open Nos. 5-159757 and 7-57788). And a small prismatic battery having a thickness of about 2 mm to 15 mm (Japanese Patent Laid-Open Nos. 8-195204, 8-138727, 9-213286, etc.) are known. Each of these lithium secondary batteries has a purpose corresponding to the miniaturization and thinning of portable devices. For example, the lithium secondary battery has a thickness of several millimeters that can be stored on the bottom of a portable personal computer and has an area of about JIS A4 size. Although the thin battery which has is also disclosed (Unexamined-Japanese-Patent No. 5-283105), since an energy capacity is 10 Wh or less, a capacity | capacitance is too small as a secondary battery for electrical storage systems.
[0007]
[Problems to be solved by the invention]
In the case of a flat battery as described above, as the thickness of the battery is reduced, the area of the front and back surfaces of the battery with respect to the thickness of the battery increases, and the force for pressing the electrode surface accommodated in the battery decreases. In particular, when a flat battery is produced in a large-sized lithium secondary battery (energy capacity 30 Wh or more) used in a power storage system, the tendency is strong. For example, in the case of a lithium ion battery of 100 Wh class thickness 6 mm, the battery The size of the front and back surfaces is 600 cm ² (one side), which is very large compared to the thickness. Therefore, when a flat large lithium secondary battery is produced, there remains a problem that the thickness of the battery becomes thicker than the design or the internal resistance and capacity of the battery vary.
[0008]
An object of the present invention is to provide a flat non-aqueous secondary battery having a large capacity of 30 Wh or more and a volume energy density of 180 Wh / l or more and excellent in dimensional accuracy.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a nonaqueous secondary battery having a flat shape in which a nonaqueous electrolyte containing a positive electrode, a negative electrode, a separator, and a lithium salt is housed in a battery container, wherein the nonaqueous secondary battery is a non-aqueous secondary battery. 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, and the pressure in the battery container is less than atmospheric pressure. A non-aqueous secondary battery is provided.
[0010]
The non-aqueous secondary battery manufacturing method of the present invention is the non-aqueous secondary battery manufacturing method, wherein the positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte are accommodated in the battery container. The final sealing step of the battery container is performed in a state where the pressure in the battery container is less than atmospheric pressure.
[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 is a diagram showing 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 a diagram of the battery shown in FIG. It is a side view which shows the structure of the electrode laminated body accommodated in an inside.
[0012]
As shown in FIGS. 1 and 2, the non-aqueous secondary battery according to the present embodiment includes a battery container including an upper lid 1 and a bottom container 2, a plurality of positive electrodes 101a and negative electrodes housed in the battery container. 101b, 101c, and an electrode laminate including 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 FIGS. 1 and 2 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 the case of a secondary battery, for example, it can be used in 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 of being insulated from the battery container, that is, the upper lid 1.
[0014]
The upper lid 1 and the bottom container 2 are welded by melting the upper lid all around the point A shown in the enlarged view of FIG. The upper lid 1 is provided with an electrolytic solution injection port 5, and after the electrolytic solution injection, is sealed using a sealing film 6 made of an aluminum-modified polypropylene laminate film. In this case, the sealing film 6 can also have a safety valve for releasing when the internal pressure inside the battery rises. The pressure in the battery container after the final sealing step with the sealing film 6 is less than atmospheric pressure, preferably 650 Torr or less, more preferably 550 Torr or less. 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. When the internal pressure is equal to or higher than atmospheric pressure, the battery becomes larger than the design thickness or the variation in battery thickness increases, resulting in variations in the internal resistance and capacity of the battery.
[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, when safety is important, 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 further, lithium, oxygen, etc. are in excess of the stoichiometric ratio. LiMn ₂ O ₄ prepared in the above manner.
[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. In particular, from the viewpoint of safety, a polyacene-based substance that generates a small amount of heat at around 150 ° C. or a material containing the same is desirable.
[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, and glass. Polyethylene and polypropylene are preferable from the viewpoints of cost, moisture content, and the like. . When polyethylene or polypropylene is used as the separator 104, the weight per unit area of the separator is preferably 5 g / m ² or more and 30 g / m ² or less, more preferably 5 g / m ² or more and 20 g / m ² or less. still more preferably 8 g / m ² or more 20 g / m ² or less. If the basis weight of the separator exceeds 30 g / m ^2, the separator is too thick, or the porosity is reduced, it is not preferable because the internal resistance of the battery is high, if it is less than 5 g / m ^2, practical strength Is not preferable.
[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 depending on the use conditions such as the positive electrode material, the negative electrode material, and the charging voltage, and more specifically. Specifically, 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 these two types The thing etc. which melt | dissolved in organic solvents, such as the above mixed solvents, are illustrated. 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]
By the way, in general, a large lithium secondary battery (energy capacity of 30 Wh or more) for a power storage system can obtain a high energy density, but its battery design is an extension of a small battery for portable devices. However, the shape of the battery is a cylindrical shape, a rectangular shape or the like that is three times or more that of a small battery for portable devices. 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.
[0021]
The flat non-aqueous secondary battery according to the present embodiment has a large heat radiation area and is advantageous for heat radiation, and thus can solve the above-described problems. That is, the nonaqueous secondary battery of the present embodiment has a flat shape, and the thickness thereof is preferably less than 12 mm, more preferably less than 10 mm, and further preferably less than 8 mm. As for the lower limit of the thickness, 2 mm or more is practical in consideration of the filling factor of the electrode and the battery size (the area becomes larger in order to obtain the same capacity as the thickness is reduced). 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.
[0022]
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, etc. 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. Further, from the viewpoint of ease of manufacture, the flat front and back surfaces of the battery are rectangular, and a notebook shape as shown in FIG. 1 is preferable.
[0023]
The materials used for the top lid 1 and the bottom container 2 to be the battery container are appropriately selected depending on the use and shape of the battery, and are not particularly limited, and iron, stainless steel, aluminum, etc. are common and practical. is there. Further, the thickness of the battery container is appropriately determined depending on the use and shape of the battery or the material of the battery case, and is not particularly limited. Preferably, the thickness of the portion of 80% or more of the battery surface area (the thickness of the portion having the largest area constituting the battery container) is 0.2 mm or more. If the 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 thickness of the same part is desirably 1 mm or less. If this thickness exceeds 1 mm, the force to hold down the electrode surface increases, but it is not desirable because the internal volume of the battery is reduced and a sufficient capacity cannot be obtained, or the weight increases. Preferably it is 0.7 mm or less.
[0024]
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, etc. However, the rise in battery temperature is small, and it can have excellent heat dissipation characteristics. Therefore, the heat storage of the battery due to internal heat generation is reduced, and as a result, it is possible to suppress the thermal runaway of the battery, and it is possible to provide a non-aqueous secondary battery excellent in reliability and safety.
[0025]
Next, the final sealing step in the method for manufacturing the non-aqueous secondary battery configured as described above will be described in detail. Conventionally, the method of sealing the inside of the battery at atmospheric pressure or lower has been used for a small film battery having a thickness of 1 mm or less using a solid electrolyte or a gel electrolyte. In this case, for example, as shown in FIGS. 3A and 3B, the drawn upper lid 51 and the flat plate lower lid 52 (or the drawn lower lid 52 shown in FIG. 3C). The final sealing step was performed by heat-sealing all or one side of the outer peripheral portion S of the resin using a thermoplastic resin 53 such as a modified polypropylene resin under reduced pressure.
[0026]
On the other hand, in the case of a large battery having an energy capacity exceeding 30 Wh as in the present invention, it is difficult to divert the technique used in the small film battery as described above in the final sealing step for the following reason. That is, in the case of a flat large battery as in the present invention, the area of the battery itself is large, the fusion area thereof is also large, a huge heat fusion apparatus is required, and the reliability of the fusion part is lacking. . Further, when the electrolytic solution is a solution, it is difficult to heat-seal the electrode after impregnating the electrode with the electrolytic solution while preventing the adhesion surface from being wetted by the electrolytic solution. For the reasons described above, in the case of a large battery, it has not been conventionally performed to heat-seal the outer peripheral portion of the battery container like a conventional small film battery. In addition, the above-described problem relating to the battery thickness of the present invention is not particularly a problem in the case of a conventional large battery having a large thickness because the thickness, shape, etc. of the battery can can be adequately addressed.
[0027]
However, in the non-aqueous secondary battery of this embodiment, the positive electrode 101a, the negative electrodes 101b and 101c, the separator 104, and the non-aqueous electrolyte are accommodated in the battery container so that the internal pressure of the battery after completion is less than atmospheric pressure. The above-described problems are solved by performing the final sealing step of the battery container in a state where the pressure in the battery container is lower than the atmospheric pressure. Here, the method of making the inside of the battery less than atmospheric pressure is not particularly limited, but specifically, it can be performed as follows.
[0028]
First, as shown in FIG. 2, the positive electrode 101a, the negative electrodes 101b and 101c, and the separator 104 are laminated, and the obtained electrode laminate is accommodated in the upper lid 1 and the bottom container 2, and the outer periphery of the upper lid 1 and the bottom container 2 Weld the parts. Next, the electrolytic solution is injected into the battery container from the liquid injection port 5. Next, as a final sealing step, a sealing film 6 having a low water permeability is heat-sealed by a heat-sealing type represented by the above-mentioned aluminum-modified polypropylene laminate film and aluminum-modified polyethylene laminate film. The final sealing step is not particularly limited to the above example, or after welding a metal plate or foil, or by attaching a cock to the battery container and reducing the inside of the battery to a predetermined pressure (less than atmospheric pressure), The cock may be closed.
[0029]
The pressure in the final sealing step is less than atmospheric pressure, preferably 650 Torr or less, more preferably 550 Torr or less. This pressure is determined according to the internal pressure required for the finally completed battery. Further, the peripheral length of the opening provided in the battery container for performing the final sealing step is preferably 1/10 or less, more preferably 1/20 or less, of the outer peripheral length of the battery. If the perimeter of the opening exceeds 1/10 of the perimeter, as described above, the fusion area becomes large, a huge heat fusion device is required, and the reliability of the fusion part is lacking. A problem occurs. Moreover, it is preferable that the part which provides this opening part exists in front and back except the outer peripheral part 5mm of a battery. If the opening is provided within 5 mm of the outer peripheral portion of the battery, sufficient strength cannot be obtained, and sealing failure such as leakage of the electrolyte is likely to occur, which is not preferable.
[0030]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
(1) 100 parts by weight of LiCo 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 embodiment, the application area (W1 × W2) of the positive electrode 101a is 262.5 × 192 mm ² , and is applied to both surfaces of a 20 μm current collector 105a with a thickness of 103 μm. As a result, the electrode thickness t is 226 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.
[0031]
(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 267 × 195 mm ² , and is applied to both surfaces of the 18 μm current collector 105b with a thickness of 108 μm. As a result, the electrode thickness t is 234 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 hole of φ3 is formed in the center thereof. Further, a single-sided electrode having a thickness of 126 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).
[0032]
(3) As shown in FIG. 2, 8 positive electrodes and 9 negative electrodes (2 inner surfaces) obtained in the above item (1) were used as separators 104a (polypropylene nonwoven fabric: Nippon Advanced Paper Industries, MP1050, basis weight 10 g / m). ² ) and separators 104b (polyethylene microporous membrane; Asahi Kasei HICORE 6022, basis weight 13.3 g / m ² ) are alternately stacked via separators 104, and the outer side is insulated for insulation from the battery container. A separator 104b was disposed on the outer side of the negative electrode 101c to prepare an electrode laminate. The separator 104 was arranged so that the separator 104b was on the positive electrode side and the separator 104a was on the negative electrode side.
[0033]
(4) As shown in FIG. 1, a SUS304 thin plate having a thickness of 0.5 mm was squeezed to a depth of 5 mm to form a bottom container 2, and the upper lid 1 was also made of a SUS304 thin plate having a thickness of 0.5 mm. Next, as shown in FIG. 5, the positive electrode terminal 3 made of aluminum and the negative electrode terminal 4 made of copper (head portion 6 mmφ, screw portion of the tip M <b> 3) were attached to the upper lid 1. The positive and negative terminals 3 and 4 were insulated from the upper lid 1 by a polypropylene gasket.
[0034]
(5) The hole of each positive electrode current collecting piece 106a of the electrode laminate prepared in the above item (3) is put into the positive electrode terminal 3, and the hole of each negative electrode current collecting piece 106b is put into the negative electrode terminal 4, respectively. Connected with bolts. The connected electrode laminate was fixed with an insulating tape, and the corner A in FIG. 1 was laser welded over the entire circumference. 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 weight ratio of 1: 1 as an electrolytic solution from the pouring port 5 (6 mmφ). Next, under a reduced pressure of 300 Torr, a sealing film 6 made of an aluminum foil-modified polypropylene laminate film having a thickness of 0.08 mm punched to 12 mmφ was subjected to a temperature of 250 to 350 ° C., a pressure of 1 to 3 kg / cm ² , and a pressing time. The liquid injection port 5 was sealed by heat-sealing under conditions of 5 to 10 seconds.
[0035]
(6) When the thicknesses of the five batteries obtained as described above were measured at five points T1 to T5 shown in FIG. 6, it was between 6.15 mm and 6.2 mm for all the batteries. It was. Further, when the internal resistance was measured using an alternating current of 1 KHz, it was 5 mΩ to 6 mΩ. The battery was charged to 4.1 V with a current of 5 A, then subjected to constant current and constant voltage charging to apply a constant voltage of 4.1 V for 12 hours, and then discharged to 2.5 V with a constant current of 5 A. The discharge capacity was 23.1 Ah, and the energy capacity was 84 Wh. The rise in battery temperature at the end of discharge was less than when a box-shaped (thickness of 12 mm or more) battery having the same capacity was assembled.
(Comparative Example 1)
A battery was assembled in the same manner as in Example 1 except that the final sealing step in item (5) of Example 1 was performed under atmospheric pressure. The thickness of the obtained battery was T1 = 6.7 mm, T2 = 6.5 mm, T3 = 6.4 mm, T4 = 6.4 mm, T5 = 6.4 mm, and varied greatly from 6.4 to 6.7 mm. The thickness was about 10% thicker than the design thickness of 6.00 mm. Further, four batteries were assembled, but the thickness of the five batteries varied from 6.4 to 6.8 mm, and the internal resistance varied greatly from 8 mΩ to 12 mΩ. Moreover, when charging / discharging was performed in the same manner as in Example 1 and the discharge capacity was measured, it varied greatly from 20 Ah to 16 Ah.
[0036]
【The invention's effect】
As is apparent from the above, according to the present invention, a flat battery, particularly a flat battery having a large capacity and a high volumetric energy density, has a high thickness accuracy and an internal resistance by making the inside of the battery less than atmospheric pressure. In addition, it is possible to provide a non-aqueous secondary battery with little variation in capacity.
[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 an explanatory view of a sealing structure of a conventional small film battery.
FIG. 4 is an explanatory diagram of a positive electrode, a negative electrode, and a separator used in an example of a nonaqueous secondary battery of the present invention.
FIG. 5 is an explanatory diagram of an upper lid used in an example of a non-aqueous secondary battery of the present invention.
FIG. 6 is an explanatory diagram of battery thickness measurement points in an example of a non-aqueous secondary battery of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Top cover 2 Bottom container 3 Positive electrode terminal 4 Negative electrode terminal 5 Injection hole 6 Sealing film 101a Positive electrode (both sides)
101b Negative electrode (both sides)
101c Negative electrode (single side)
104, 104a, 104b Separator 105a Positive electrode current collector 105b Negative electrode current collector 106a Positive electrode current collector piece 106b Negative electrode current collector piece

Claims (7)

A non-aqueous secondary battery having a flat shape 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,
The non-aqueous secondary battery 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,
The pressure of the battery container is state, and are less than the atmospheric pressure,
The battery container is provided with an opening for electrolyte injection at any location except within 5 mm from the outer periphery of the battery on the front and back surfaces in a flat shape, and the opening has a circumference of 1 / of the outer circumference of the battery. A non-aqueous secondary battery characterized by being 10 or less and sealed . The non-aqueous secondary battery according to claim 1, wherein the opening of the battery container is sealed by thermally welding a sealing film. The non-aqueous secondary battery according to claim 1, wherein the sealing film is made of any one of an aluminum-modified polypropylene laminate film and an aluminum-modified polyethylene laminate film. The nonaqueous secondary battery according to any one of claims 1 to 3, wherein the pressure in the battery container is 650 Torr or less. The non-aqueous secondary battery according to any one of claims 1 to 4, wherein a shape of the front and back surfaces of the flat shape is a rectangle. The nonaqueous secondary battery according to any one of claims 1 to 5 , wherein a thickness of the battery container is 0.2 mm or more and 1 mm or less. It is a manufacturing method of the nonaqueous system rechargeable battery in any one of Claim 1-6,
The positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte are accommodated in the battery container, and a final sealing step of the opening in the battery container is performed in a state where the pressure in the battery container is less than atmospheric pressure. A method for producing a non-aqueous secondary battery.

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