JP2002246068A - Nonaqueous secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous secondary cell having a flat shape, a thickness less than 12 mm, a large capacity of 30 Wh or larger, and volume energy density of 180 Wh/l, realizing high weight energy density, and provided with a cell vessel which is light in weight and having sufficient strength. SOLUTION: This nonaqueous secondary cell stores a positive electrode, a negative electrode, a separator, and nonaqueous electrolyte, containing lithium salt in a cell vessel and has flat shape, and if has a thickness of less than 12 mm, energy capacity of 30 Wh or larger and volume energy density of 180 Wh/l or larger. The cell vessel has a metal plate, having a thickness of 0.1 mm or more and a resin layer provided on at least a face on one side of the metal plate, and is provided with a part made of a metal-resin laminate plate having a thickness of lamination of less than 1 mm as the main constituent member, and the pressure in the cell vessel is lower than the atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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]

2. Description of the Related Art In recent years, from the viewpoint of effective use of energy for resource saving and global environmental problems, a home-use decentralized power storage system for late-night power storage and power storage for photovoltaic power generation has been developed. Power storage systems are attracting attention. For example, JP-A-6-86463 discloses that
As a system capable of supplying energy to an energy consumer under optimum conditions, a total system combining electricity supplied from a power plant, gas cogeneration, a fuel cell, a storage battery, and the like has been proposed. A secondary battery used in such a power storage system has an energy capacity of 10
Unlike small secondary batteries for portable devices of Wh or less, large batteries having large capacities are required. For this reason, in the above-described power storage system, a plurality of secondary batteries are stacked in series, and usually used as a battery pack having a voltage of, for example, 50 to 400 V. In most cases, a lead battery is used.

On the other hand, in the field of small rechargeable batteries for portable equipment, nickel-metal hydride batteries and lithium rechargeable batteries have been developed as new types of batteries in order to meet the needs of small size and high capacity, and volume energy of 180 Wh / l or more has been developed. Batteries having a density are commercially available. In particular, lithium-ion batteries
It has the potential of a volume energy density exceeding 350 Wh / l, and its reliability, such as safety and cycle characteristics, is superior to a lithium secondary battery using lithium metal as a negative electrode. Prolonged.

[0004] In response to this, in the field of large-sized batteries for power storage systems, lithium-ion batteries have been targeted as candidates for high-energy density batteries, and lithium battery power storage technology research associations (LIBES) and others have been vigorously developing them. Have been.

The energy capacity of these large lithium ion batteries is about 100 Wh to 400 Wh, and the volume energy density is 200 to 300 Wh / l, which is at the level of a small secondary battery for portable equipment. Its shape is
Diameter 50mm-70mm, length 250mm-450mm
And a rectangular prism having a thickness of 35 mm to 50 mm or an oblong prism or the like are typical.

[0006] However, although these large lithium-ion batteries can provide high energy density, their diameter or thickness is more than three times that of small-sized batteries for portable equipment because their battery design is an extension of small-sized batteries for portable equipment. Battery shape such as a cylindrical shape and a square shape. In this case, heat easily accumulates inside the battery due to Joule heat generated by the internal resistance of the battery during charge and discharge, or internal heat generated by the battery due to a change in entropy of the active material due to the entrance and exit of lithium ions. For this reason, the difference between the temperature inside the battery and the temperature near the battery surface is large, and the internal resistance differs accordingly. As a result, the charge amount and the voltage are likely to vary. In addition, since a plurality of batteries of this type are used as assembled batteries, the heat storage easiness varies depending on the installation position of the batteries in the system, and variations among the batteries occur, and accurate control of the entire assembled battery is not achieved. It becomes difficult. In addition, the battery temperature rises due to insufficient heat dissipation during high-rate charge / discharge, etc., and the battery is placed in an unfavorable state. Problems such as induction of reliability and, in particular, safety remain.

[0007] In order to solve the above problems, WO99 / 60
No. 652 is 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, and the thickness of the non-aqueous secondary battery is Are non-aqueous secondary batteries having a flat shape of less than 12 mm, an energy capacity of 30 Wh or more, and a volume energy density of 180 Wh / l or more. It proposes that the battery has a unique battery shape (flat shape) to solve the problems of reliability and safety caused by the heat storage, which is a barrier to practical application.

[0008]

By the way, a battery container generally has a function of withstanding an external impact such as collision of an object, and of sandwiching and holding an electrode housed in the battery container. As described above, the material, the shape, and the like are selected according to the battery size, the battery shape, the use environment of the battery, and the like. In particular, in the case of a large battery, unlike the small battery, the design of the battery container, that is, the determination of the material, shape, and the like is particularly important in order to ensure the reliability and safety of the battery. For example, when the battery shape is rectangular, a high-strength material is required because the flat plate portion has a lower pressure resistance than a cylindrical battery, so stainless steel or iron is generally used as the material of the battery container. It is used for

However, the thickness as described above is 12 m.
In a large-sized flat battery having a large capacity (30 Wh or more) of less than m, a flat member having a large area exists, and the ratio of the volume of the battery container material to the whole battery is larger than that of a square or cylindrical battery. . Therefore, when stainless steel or iron is used for the battery case in such a flat battery, there is a problem that the weight of the entire battery is increased for the size of the battery. In other words, the conventional flat-shaped battery has a problem that the weight energy density is extremely reduced although a high volume energy density can be realized.

An object of the present invention is to provide a flat non-aqueous secondary battery having a thickness of less than 12 mm, which has high capacity, high volume energy density and high weight energy density. It is in.

[0011]

In order to achieve the above object, the present invention provides a flat non-aqueous secondary battery containing a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt 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 battery container has a metal plate having a thickness of 0.1 mm or more, and a resin layer provided on at least one surface of the metal plate, and the laminated thickness of these is less than 1 mm. The present invention provides a non-aqueous secondary battery characterized by comprising a portion made of a laminated metal-resin plate as a main constituent member, wherein the pressure in the battery container is lower than the atmospheric pressure.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-aqueous secondary battery according to one embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a flat rectangle (note type) according to an embodiment of the present invention.
FIG. 2 is a plan view and a side view of the non-aqueous secondary battery for a power storage system of FIG. 1, and FIG. 2 is a side view showing a configuration of an electrode laminate housed inside the battery shown in FIG.

As shown in FIGS. 1 and 2, the present embodiment
Is a non-aqueous secondary battery comprising a top lid 1 and a bottom container 2.
Container and a plurality of positive electrodes 1 housed in the battery container
01a, negative electrodes 101b and 101c, and separator 10
4 of the present invention. Of this embodiment
In the case of a flat nonaqueous secondary battery such as
101b (or the negative electrode 101 disposed on both outer sides of the laminate)
c), for example, as shown in FIG.
The layers are alternately arranged and laminated via
The number of layers and the like are not particularly limited to the arrangement of
Various changes can be made according to the amount and the like. FIG. 1 and FIG.
The shape of the non-aqueous secondary battery shown in FIG.
mx 210 mm wide x 6 mm thick.
LiMn _TwoO_FourAnd carbon materials for the negative electrodes 101b and 101c
For example, in the case of a lithium secondary battery,
Can be used.

As shown in FIG. 1, a positive terminal 3 and a negative terminal 4 are attached to the upper lid 1 of the battery container in a state of being insulated from the upper lid 1, and each of the positive terminals 3 shown in FIG. The positive electrode current collector 105a of the positive electrode 101a is electrically connected, and the negative electrodes 101b and 101c are connected to the negative electrode terminal 4.
Negative electrode current collector 105b is electrically connected.

An upper lid 1 and a lower container 2 constituting a battery container
Is composed of, for example, a metal-resin laminate plate as shown in FIG. As shown in the figure, the metal-resin laminate plate includes a metal plate 53, and resin layers 51a, 52a, 52b bonded to both surfaces of the metal plate 53 by adhesive layers 52a, 52b.
51b.

The metal used for the metal plate 53 is not particularly limited, but for example, stainless steel, iron, aluminum, aluminum alloy,
It is preferable to use copper or a copper alloy. Also, the resin layer 51
The resin material used for a and 51b is also not particularly limited, but polyester, nylon or polyethylene represented by PET in terms of versatility and cost.
Polyolefin such as polypropylene is preferable, and polyester and polyolefin excellent in electrolytic solution resistance are preferable for the resin layer 51b inside the battery. Further, when the upper lid 1 and the bottom container 2 are joined by heat fusion as described later, it is preferable to use a polyolefin. The adhesive layers 52a and 52b are formed of the metal plate 53 and the resin layer 51a,
Although it is appropriately selected according to the material of 51b, for example, an acrylic adhesive, a rubber adhesive, or the like can be used.
Further, the resin layers 51a and 51b can be formed by heat-sealing a resin film, and in this case, the adhesive layers 52a and 52b are not necessarily required.

The metal plate 53 is used to obtain a sufficient strength against pressure and impact and a shape-retaining strength in a battery manufacturing process.
Preferably, the thickness is 0.1 mm or more. In addition, there is also an advantage that it is not necessary to reinforce the battery container. From such a viewpoint, the thickness of the metal plate 53 is more preferably set to 0.15 mm or more, and 0.2 mm or more.
It is more preferable to make the above. In addition, the thickness of the resin layer 51a outside the battery is preferably 0.05 mm or more, more preferably 0.1 mm or more, so that sufficient strength against external impact contact is obtained. On the other hand, the thickness of the resin layer 51b inside the battery is preferably set to 0.02 mm or more from the viewpoint of insulation between the electrodes, but is preferably set to 0.05 mm or more from the viewpoint of long-term durability. More preferred.

It is desirable that the thickness of the entire metal-resin laminate plate be 1 mm or less. This thickness is 1mm
When the value exceeds, although the required strength can be obtained, the internal volume of the battery may be reduced and a sufficient capacity may not be obtained, and the weight may increase. From this viewpoint, it is more preferable that the thickness of the metal-resin laminate plate be 0.7 mm or less. It is not always necessary that all parts of the battery container be made of a metal-resin laminate plate, and it is sufficient that a part made of a metal-resin laminate plate is provided as a main component. However, in order to sufficiently achieve the effects of the present invention described later, the battery container 80
% Or more, preferably 90% or more of the metal-resin laminate.

The structure of this metal-resin laminate is shown in FIG.
However, the configuration is not limited to those described above, and the configuration may be determined in consideration of the battery manufacturing process, use environment, and the like.
For example, as the metal-resin laminate plate of the present invention, of the front and back surfaces of the metal plate, those provided with a resin layer only on the outer or inner surface of the battery container, the metal plate being exposed on a part of the resin layer Or a laminate of a plurality of resin layers can be used.

The battery is sealed as follows. As shown in FIG. 1, the upper lid 1 and the bottom container 2 can be welded, for example, by melting the peripheral edge of the upper lid 1 at a point A shown in an enlarged view in FIG. At this time, it is preferable to form a portion where no resin layer is provided on the periphery of the upper lid 1 and the bottom container 2 and weld this portion. Instead of welding, for example, as shown in FIG. 4, the peripheral edges of the upper lid 1 and the bottom container 2 may be heat-sealed using a heat-sealing resin 50 such as denatured polypropylene. In this case, when the resin 51b on the inside of the battery in FIG. 3 is a heat-sealing resin, and the joining portion of the upper lid 1 and the bottom container 2 is melted,
Since the sealing can be performed, there is no need to separately prepare the heat-sealing resin 50, and the manufacturing cost can be reduced.

Subsequently, after the electrolyte is injected into the injection port 5 formed in the upper lid 1, as a final sealing step, the injection port 5 is sealed using a sealing film 6 made of, for example, an aluminum-modified polypropylene laminated film. I do. This final sealing step is preferably performed after at least one charging operation as described later.

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. A lithium composite cobalt oxide, a lithium composite nickel oxide, a lithium composite manganese oxide, or a mixture thereof is used. Further, a system in which one or more different metal elements are added to these composite oxides can be used, and a high-voltage, high-capacity battery can be obtained, which is preferable. When importance is placed on safety, which is the highest priority in practical application of a large lithium secondary battery, it is preferable to use a positive electrode mainly composed of manganese oxide having a high thermal decomposition temperature. Examples of the manganese oxide include a lithium composite manganese oxide represented 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 added in excess of the stoichiometric ratio. _{1 + x} Mn _2-y O ₄ .

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. A material capable of doping and undoping lithium can be used for safety, cycle life, and the like. This is preferable because the reliability of the device is improved. As a material capable of doping and undoping lithium, a graphite-based material, a carbon-based material, a tin oxide-based material, which is used as a negative electrode material of a known lithium ion battery,
Examples thereof include metal oxides such as silicon oxides, and conductive polymers typified by polyacene-based organic semiconductors.

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 made of a nonwoven fabric. In this case, cycle characteristics are improved. . Also, the material of the separator 104 is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene, polyamide, kraft paper, glass, and cellulosic materials, depending on the heat resistance and safety design of the battery. It is determined as appropriate.

As the electrolyte of the non-aqueous secondary battery of the present invention, a known non-aqueous electrolyte containing a lithium salt can be used. The electrolyte is appropriately determined according to the use conditions such as the positive electrode material, the negative electrode material, and the charging voltage. Specifically, LiPF ₆ , Li
Lithium salts such as BF ₄ and LiClO ₄ are mixed with propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyrolactone, methyl acetate, methyl formate, or a mixed solvent of two or more of these. Examples thereof include those dissolved in an organic solvent. Further, the concentration of the electrolytic solution is not particularly limited, but is generally set at 0.1.
5 mol / l to 2 mol / l is practical. Naturally, it is preferable to use an electrolyte having a water content of 100 ppm or less. In addition, the non-aqueous electrolyte used in this specification means a concept including a non-aqueous electrolyte and an organic electrolyte, and also a concept including a gel or solid electrolyte.

The non-aqueous secondary battery configured as described above can be used for home power storage systems (nighttime power storage, cogeneration, solar power generation, etc.), power storage systems for electric vehicles, etc. It can have capacity and high 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 /
1 or more, more preferably 200 Wh / l. When the energy capacity is less than 30 Wh or when the volume energy density is less than 180 Wh / l, the capacity is small for use in a power storage system, and it is necessary to increase the number of series-parallel batteries in order to obtain a sufficient system capacity. In addition, it is not preferable for a power storage system because a compact design is difficult.

The non-aqueous secondary battery of the present embodiment has a flat shape and a thickness of less than 12 mm, more preferably less than 10 mm. The lower limit of the thickness is practically 2 mm or more in consideration of the filling rate of the electrode and the battery size (the smaller the thickness, the larger the area for obtaining the same capacity). When the thickness of the battery is 12 mm or more, it is difficult to sufficiently radiate 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,
As a result of the difference in the internal resistance, the variation in the charge amount and the voltage in the battery increases. The specific thickness depends on the battery capacity,
Although it is appropriately determined according to the energy density, it is preferable to design the maximum thickness so as to obtain expected heat radiation characteristics.

Further, the non-aqueous secondary battery of the present embodiment can have, for example, various shapes such as a flat, front and back surface having a rectangular shape, a circular shape and an oval shape. However, it may be a polygon such as a triangle and a hexagon. Further, it may be a cylindrical shape such as a thin-walled cylinder. In the case of a cylindrical shape, the thickness of the cylinder is the thickness referred to here.
Further, from the viewpoint of ease of production, the flat front and back surfaces of the battery are preferably rectangular, and a notebook-type shape as shown in FIG. 1 is preferable.

As described above, in this embodiment, the battery container is made of a metal-resin laminate plate and the thickness of the non-aqueous secondary battery is designed to be less than 12 mm, so that this battery has a large capacity of 30 Wh or more. In addition, even when high-rate charging and discharging are performed in the case of having a high energy density of 180 Wh / l, excellent heat radiation characteristics can be realized, and a rise in battery temperature can be suppressed. Accordingly, heat storage of the battery due to internal heat generation can be 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. In particular, in the present embodiment, since the battery container is formed of a metal-resin laminate plate, sufficient strength against pressure and impact can be realized, and the weight of the battery container can be significantly reduced. As a result, although different depending on the battery thickness and the battery surface area, the weight energy density can be improved to about 1.2 to 1.6 times as compared with the case where the battery container is constituted by the stainless steel plate alone.

Incidentally, in the above-mentioned flat battery, particularly a battery having a thickness of 8 mm or less, it is necessary to reduce the thickness of the material constituting the battery container in order to obtain a high volume energy density. However, in this case, the internal resistance of the battery may be increased, or the cycle life may be reduced to affect the battery performance. On the other hand, in the present embodiment, as described below, it has been found that the above-described reduction in battery performance can be prevented by sealing the inside of the battery container so that the inside of the battery container becomes lower than the atmospheric pressure. Hereinafter, the setting of the pressure in the battery container will be described in detail.

As described above, in order to make the internal pressure of the battery lower than the atmospheric pressure, the positive electrode 101 a and the negative electrode 101 a
b, 101c, the separator 104, and the non-aqueous electrolyte are accommodated in a battery container, and the final sealing step of the battery container is performed in a state where the pressure in the battery container is lower than the atmospheric pressure. This final sealing step is preferably performed after at least one charging operation. In this case, a gas may be generated inside due to decomposition of the electrolytic solution in the early stage of the first charging. In this case, if the final sealing step is performed at a pressure lower than the atmospheric pressure without performing the charging operation, the subsequent first charging may be performed. This is because the inside of the battery is pressurized (atmospheric pressure or more) by the charging operation, the thickness of the battery is increased, the internal resistance and the capacity of the battery are varied, and stable cycle characteristics may not be obtained. In particular, graphite for the negative electrode,
When a liquid electrolyte using a lithium composite oxide is used for the positive electrode, gas is easily generated.

This charging operation employs various conditions according to the type of the positive electrode material, the negative electrode material, the separator, the electrolyte used in the battery, the water content and impurities of these materials, the voltage at which the battery is used, and the like. For example, the battery is charged at a rate of about 4 to 8 hours to the operating voltage of the battery, a constant voltage is applied as necessary, and the battery is discharged at a rate of about 8 hours to the normal lower limit voltage. After the charging operation, a final sealing step may be performed. Further, the battery may be sealed after performing only the charging operation of the capacity of the battery or less, and various charging operations such as sealing after repeating charging and discharging two or more times are also possible. It is important to maintain the internal pressure of the battery below atmospheric pressure.

As described above, in this embodiment, after the gas is generated by performing the charging operation, the final sealing step is performed at a pressure lower than the atmospheric pressure. The problem that characteristics are deteriorated can be solved. In this case, when the first charging operation is performed, it is preferable that the inside of the battery is kept at a pressure lower than the atmospheric pressure, but the pressure inside the battery at this time is not particularly limited.

The method for reducing the inside of the battery to a pressure lower than the atmospheric pressure is not particularly limited. Specifically, the method can be performed as follows.

First, as shown in FIG.
After the negative electrodes 101b and 101c and the separator 104 are stacked, and the obtained electrode laminate and the like are accommodated in the upper lid 1 and the bottom container 2, the peripheral edges of the upper lid 1 and the bottom container 2 are welded or thermally fused. Next, an electrolytic solution is injected into the battery container from the liquid inlet 5 shown in FIG. Subsequently, for the temporary sealing, the above-described aluminum-modified polypropylene laminate film,
A heat-sealing type sealing film 6 having a low moisture permeability represented by an aluminum-modified polyethylene laminated film.
The injection port 5 is once closed by using, and then the sealing film 6 is removed after charging at least once as described above. In addition, the method of the temporary sealing is not particularly limited to the above-described example. For example, the inlet 5 may be temporarily sealed using a screw or the like, or a state in which water is removed, for example, air. In an environment where the air is blocked or in a dry atmosphere having a dew point of −40 ° C. or less, the above-described charging operation may be performed without sealing.

Next, as a final sealing step, the sealing film 6 is heat-sealed. The method used in the final sealing step is not particularly limited to the above example, and the inside of the battery is brought to a predetermined pressure (less than atmospheric pressure) by welding a metal plate or foil, or attaching a cock to the battery container. After reducing the pressure, the cock may be closed.

In the above-mentioned final sealing step, the pressure in the battery is set to be lower than the atmospheric pressure, but 8.66 × 10 ⁴
Pa (650 Torr) or less.
33 × 10 ⁴ Pa (550Torr) is more preferably equal to or less than. This is because when the pressure in the battery container becomes equal to or higher than the atmospheric pressure, the battery tends to be larger than the design thickness, and the variation in the thickness of the battery tends to be large, whereby the internal resistance and the capacity of the battery tend to vary. It is. This is particularly effective when a thin metal-resin laminate plate is used for a battery container as in the present embodiment. The pressure is determined according to the internal pressure required for the finally completed battery in consideration of the separator used, the type of electrolyte, the material and thickness of the battery container, the shape of the battery, and the like.

The peripheral length of the inlet 5 provided in the battery container for performing the final sealing step is 1/1/1 of the outer peripheral length of the battery.
It is preferably set to 0 or less, more preferably 1/20 or less. If the perimeter of the injection port 5 exceeds 1/10 of the outer perimeter, the fusion area becomes large as described above, and a huge heat fusion device is required, and the reliability of the fusion portion is lacking. Problems occur. Further, it is preferable that the portion where the injection port 5 is provided is located on one of the front and back surfaces except for the outer peripheral portion 5 mm of the battery. If the injection port 5 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.

[0039]

The present invention will be described more specifically below with reference to examples of the present invention.

(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 N-methylpyrrolidone (NM)
P) 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. FIG.
(A) is an explanatory view of a positive electrode. In this embodiment, the coating area (W1 × W2) of the positive electrode 101a is 262.5 × 1
92 mm ² and 110 μm on both sides of a 20 μm current collector.
m. As a result, the electrode thickness t is 2
It is 40 μm. Further, on the short side of the electrode, there is provided a positive electrode current collector 106a to which no electrode material is applied,
A hole having a diameter of 3 mm is formed at the center.

(2) Graphitized mesocarbon microbeads (MCMB, manufactured by Osaka Gas Chemical Co., Ltd., product number 6-28) 10
0 parts by weight 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 on both sides of a 14 μm-thick copper foil serving as a current collector, dried, and then pressed to obtain a negative electrode. FIG. 5B is an explanatory diagram of the negative electrode. The application area (W1 × W2) of the negative electrode 101b is 2
It is 67 × 195 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, on the short side of the electrode, a negative electrode current collector piece 106b to which no electrode material is applied is provided, and a hole having a diameter of 3 mm is formed at the center thereof. Further, a single-sided electrode having a thickness of 104 μm was formed in the same manner except that the coating was performed on one side only. The single-sided electrode is disposed outside in the electrode laminate of item (3) (101c in FIG. 2).

(3) As shown in FIG. 2, eight positive electrodes and nine negative electrodes (two on one side) obtained in the above item (1) were used as separators A104a (rayon-based, basis weight 12.6 g / m ² ). And separator B104b (polyethylene microporous membrane; basis weight 1)
3.3 g / m ² ) alternately via a separator 104, and a separator B 104b further outside the outer negative electrode 101c for insulation from the battery container.
Were arranged to form an electrode laminate. The separator 1
04 was arranged such that the separator A 104a was on the positive electrode side and the separator B 104b was on the negative electrode side.

(4) As shown in FIG. 6, the bottom container 2 constituting the battery container is prepared by forming a metal-resin laminate plate having a thickness of 0.5 mm into a tray having a depth of 4.9 mm by drawing. The upper lid 1 was made of a metal-resin laminate plate having a thickness of 0.5 mm in a flat plate shape. The metal-resin laminate used here has the structure shown in FIG. 3, and 0.3 mm aluminum is used as the metal plate 53.
The resin layer 51a made of biaxially stretched nylon is laminated on the outer surface of the battery through an adhesive layer 52a, and the resin layer 51b made of polypropylene is laminated on the inner surface of the battery via an adhesive layer 52b. .

As shown in FIG. 6, a positive electrode terminal 3 made of aluminum and a negative electrode terminal 4 made of copper (head 6 mm
φ, the screw portion of the tip M3). The positive and negative terminals 3 and 4 are made of a polypropylene gasket for the top lid 1.
And insulated.

(5) The screw portion of the positive electrode terminal 3 is inserted into the hole of each positive electrode current collecting piece 106a of the electrode laminate prepared in the above item (3), and the negative electrode terminal 4 is inserted into the hole of each negative electrode current collecting piece 106b. After the nuts made of aluminum and copper are fastened respectively, the electrode laminate is fixed to the upper lid 1 with an insulating tape, and the upper lid 1 is formed using a heat-sealing resin 50 made of denatured polypropylene shown in FIG. And the bottom container 2 were fused. Thereafter, the liquid inlet 5 1 ethylene carbonate and diethylcarbamoyl carbonate as the electrolyte solution from (diameter: 6 mm): was injected a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in mixed solvent 1 weight ratio. Subsequently, the injection port 5 was temporarily closed under atmospheric pressure using a bolt for temporary fixing.

(6) This battery is charged to a current of 5 A up to 4.2 V, and then a constant current and constant voltage charge of applying a constant voltage of 4.2 V is performed for 12 hours, and then a constant current of 5 A is applied to the battery.
Discharged to 5V.

(7) Remove the temporary fixing bolts attached to the battery, and remove 4.00 × 10 ⁴ Pa (300 Torr).
r) under a reduced pressure of 0.0
The sealing film 6 made of an 8 mm aluminum foil-modified polypropylene laminated film was heated at a temperature of 150 to 250.
° C, pressure 98.1-294 kPa (1-3 kg / c
m ² ), the liquid injection port 5 was finally sealed by heat-sealing under the conditions of a pressurization time of 5 to 10 seconds to obtain a flat notebook battery having a thickness of 6 mm.

Subsequently, the battery was supplied with a current of 5 A and a voltage of 4.2 V.
To a constant current of 12 V for 12 hours, followed by a constant current of 5 A for 2.2 hours.
The battery was discharged to 5 V, and the capacity was confirmed. The calculated discharge capacity was 27 Ah. The energy capacity of this battery is 100 Wh, and the volume energy density is 265 Wh /
1, the weight energy density was 150 Wh / Kg.
When discharging at a constant current of 10 A, the discharge capacity is 2
4.9 Ah.

Further, when a constant current / constant voltage charging and discharging operation under the same conditions as in the item (6) is defined as one cycle, the discharging capacity at the tenth cycle when this operation is repeated for ten cycles is 24.5 Ah. there were.

[0050]

[Comparative Example 1] The bottom container 2 and the top lid 1 were made of SU having a thickness of 0.5 mm
A battery was assembled in the same manner as in the above example except that a thin plate made of S304 was used. This battery is charged to 4.2 V with a current of 5 A, and then a constant-current constant-voltage charge of applying a constant voltage of 4.2 V is performed for 12 hours, followed by a constant current of 5 A to 2.5
Discharge to V and the capacity was confirmed. The discharge capacity was 27 Ah. The energy capacity of this battery was 100 Wh, the volume energy density was 265 Wh / l, and the weight energy density was 100 Wh / Kg. When the battery was discharged at a constant current of 10 A, the discharge capacity was 24.9 Ah.

Further, when a constant current constant voltage charging and discharging operation under the same condition as that of the item (6) is defined as one cycle, the discharging capacity at the tenth cycle when this operation is repeated for ten cycles is 24.8 Ah. there were. From the above results, by changing the battery container from a stainless steel material generally used conventionally to a metal-resin laminate material,
It has been found that the weight energy density can be increased 1.4 times without lowering the battery characteristics.

[0052]

Comparative Example 2 A flat battery having the same thickness and area as in Example 1 was prepared using a metal-resin laminate film having a thickness of 0.1 mm used for a small lithium ion battery for a mobile phone. 5cm x 5cm x 5c from 1m height
When a piece of wood was dropped on the battery, the battery case was damaged, and one month later, the battery was swollen. It is probable that moisture entered from the wound. When the same experiment was performed using the battery of the example, there was no change. From these results, it was found that the metal-resin laminate used for the battery container of the present invention had sufficient strength.

[0053]

As is clear from the above, according to the present invention, a flat non-aqueous secondary having a flat shape with a thickness of less than 12 mm, a large capacity of 30 Wh or more and a volume energy density of 180 Wh / l or more. In the battery, the battery container is
A metal plate having a thickness of 0.1 mm or more, and a resin layer provided on at least one surface of the metal plate, and a portion formed of a metal-resin laminate plate having a laminated thickness of less than 1 mm; Since it is provided as a main constituent member, it is possible to reduce the weight of the battery container while sufficiently maintaining the strength of the battery container. An aqueous secondary battery can be provided.

Further, since the pressure in the battery container is set to be lower than the atmospheric pressure, even if the battery container is made of the above-mentioned material and the material having the above thickness, the atmospheric pressure acting from the outside of the battery container is applied. Thus, the function of sandwiching the electrode in the battery container and holding down the electrode is ensured.

[Brief description of the drawings]

FIG. 1 is a plan view and a side view of a non-aqueous secondary battery for a power storage system according to an embodiment of the present invention.

FIG. 2 is a side view showing a configuration of an electrode laminate housed inside the battery shown in FIG.

FIG. 3 is a sectional view showing a configuration of a battery container of the battery shown in FIG.

FIG. 4 shows a plan view and a side view of a modification of the battery shown in FIG. 1.

FIG. 5 is a plan view of a positive electrode, a negative electrode, and a separator constituting the laminate shown in FIG.

FIG. 6 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top cover 2 Bottom container 3 Positive electrode terminal 4 Negative terminal 5 Injection port 6 Sealing film 50 Heat-fused resin 51a, 51b Resin layer 52a, 52b Adhesive layer 53 Metal plate 101a Positive electrode (both surfaces) 101b Negative electrode (both surfaces) 101c Negative electrode (one surface) ) 104 separator 105a positive electrode current collector 105b negative electrode current collector 106a positive electrode current collector 106b negative electrode current collector

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Shizukuni Yada 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Kansai New Technology Research Institute Co., Ltd. (72) Haruo Kikuta Hirano, Chuo-ku, Osaka City, Osaka Prefecture F-term (reference) in Osaka Gas Co., Ltd. 1-2 1-2, Machi 4H011 AA03 CC10 EE04 FF02 GG09 HH13 KK01 KK04 5H022 AA09 CC02 5H029 AJ03 AK03 AM03 AM04 AM05 AM07 BJ04 BJ12 DJ02 DJ03 HJ04 HJ15 HJ19

Claims (8)

[Claims] A flat nonaqueous secondary battery in which a nonaqueous electrolyte containing a positive electrode, a negative electrode, a separator, and a lithium salt is contained in a battery container, wherein the nonaqueous secondary battery has a thickness of A flat shape of less than 12 mm, an energy capacity of 30 Wh or more and a volume energy density of 180 Wh / l or more, wherein the battery container has a metal plate having a thickness of 0.1 mm or more, and at least one surface of the metal plate; And a resin layer provided as a main component having a portion made of a metal-resin laminate plate having a lamination thickness of less than 1 mm, wherein the pressure in the battery container is less than atmospheric pressure. A non-aqueous secondary battery. 2. The non-aqueous secondary battery according to claim 1, wherein the metal constituting the metal-resin laminate plate is any one of stainless steel, iron, aluminum, an aluminum alloy, copper, and a copper alloy. . 3. The non-aqueous secondary battery according to claim 1, wherein the resin layer used for the metal-resin laminate plate is any one of polyester, nylon, and polyolefin. 4. The pressure in the battery container is 8.66 × 10
The non-aqueous secondary battery according to claim 1, wherein the pressure is ⁴ Pa or less. 5. The non-aqueous system according to claim 1, wherein a terminal electrically connected to the positive electrode and the negative electrode is provided on one of front and rear surfaces of the battery container. Rechargeable battery. 6. The method according to claim 1, wherein the negative electrode includes a material capable of doping and undoping lithium.
The non-aqueous secondary battery according to any one of the above. 7. The non-aqueous secondary battery according to claim 1, wherein the positive electrode contains a manganese oxide. 8. The non-aqueous secondary battery according to claim 1, wherein the flat front and back surfaces are rectangular.