JP2000268873A - Lithium secondary battery and battery device using the same - Google Patents

Abstract

(57) [Summary] [Problem] There is no risk of deterioration of characteristics due to permeation of water or an organic solvent, and there is no risk of damage to the container even after repeated charging and discharging, and it is significantly lighter and larger than before. And a battery device using the same. SOLUTION: The lithium secondary battery 2 has a flexible bag-shaped container 21 for preventing permeation of an organic solvent and moisture in an electrolytic solution.
The electrode laminate 22 and a non-aqueous organic electrolytic solution were sealed therein. The battery device was provided with pressing means 3 for pressing the lithium secondary battery 2 from the outside so as to apply a constant pressure in the electrode stacking direction of the electrode stack 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel lithium secondary battery suitable for use as a power source for, for example, electric vehicles and hybrid vehicles, or for small-scale power storage in ordinary households, shops, small factories, and the like. And a battery device using the same.

[0002]

2. Description of the Related Art A lithium secondary battery has a high energy density and energy efficiency, and can provide a higher voltage than a battery of another type in a single cell. For example, research has been conducted on small or ultra-compact power supplies for use in mobile phones and notebook computers, but recently, for example, power supplies for electric vehicles and hybrid vehicles, or in general households, shops, small factories, etc. Is expected to be used for larger batteries for small-scale power storage.

As a lithium secondary battery for such a large battery, for example, a negative electrode having a negative electrode active material such as natural graphite, which can be doped or dedoped with lithium ions, and a transition metal containing or not containing lithium, for example. A combination of a positive electrode using an oxide of the above as a positive electrode active material and a non-aqueous organic electrolytic solution obtained by dissolving a lithium salt as an electrolyte in a non-aqueous organic solvent is suitably used.

[0004] The above-mentioned lithium secondary battery has the above-mentioned high energy density and high energy efficiency, which are the inherent characteristics of a normal lithium secondary battery, and has a higher energy efficiency than a case where metallic lithium is used for the negative electrode. In addition, they exhibit high safety and a long cycle life because they do not generate precipitates such as so-called dendrites even after repeated charging and discharging.

However, since the characteristics of lithium secondary batteries are greatly deteriorated due to moisture, it is needless to say that the water-containing components at the time of manufacture are reduced, and that even during use, it is necessary to surely prevent the penetration of moisture from outside the container. . In addition, since the organic solvent is used for the electrolyte, if the organic solvent volatilizes and escapes outside the container, the composition of the electrolyte is shifted, which may cause deterioration of the characteristics. The container is required to be able to prevent both permeation of water and organic solvent.

It is known that the above-mentioned positive electrode active material expands and contracts greatly during charging and discharging. A large number of powders of this positive electrode active material are used in a container as a current collector by using a resin binder. It is also required to prevent the structure of the positive electrode bonded to the surface of the metal foil from being repeatedly expanded and contracted to loosen the resistance value of the positive electrode and thereby shorten the charge and discharge cycle life.

Therefore, in the case of a small or ultra-small battery, the expansion of the positive electrode active material can be suppressed by its own rigidity, and it is excellent in preventing moisture and organic solvents from permeating. 2. Description of the Related Art Containers made of a metal plate made of stainless steel, aluminum, or the like, having resistance, are used.

[0008]

However, if a large battery container having a capacity of, for example, 50 to 1000 Ah is to be formed of a metal such as stainless steel or aluminum, as in the case of a small battery, the charging / discharging of the battery is difficult. In order to obtain sufficient mechanical strength capable of suppressing the expansion of the positive electrode active material by its own rigidity without being damaged by expansion and contraction at the time, a considerably rugged structure is required. There is a problem that the weight of a lead-acid battery, which is widely used in the art, becomes significantly larger than that of a plastic container or the like.

[0009] This leads to a remarkable increase in the weight of the battery, which is an obstacle to the use of a lithium secondary battery as a power source for an electric vehicle or a hybrid vehicle that requires a minimum dead weight and a light weight. ing. Also, for small-scale power storage, the battery weight is preferably as small as possible in consideration of the ease of replacement and the like, and the commercialization of a lighter and larger lithium secondary battery is desired.

Among the inventors, Mashima and Yagasaki, together with several other inventors, have previously described, in such a large-sized lithium secondary battery, an inner surface of a container and an electrode laminate in which a plurality of positive and negative electrodes are laminated. In the meantime, it has been proposed to insert a pressing member such as a leaf spring so as to apply a constant pressure in the electrode stacking direction of the electrode stack (Japanese Patent Laid-Open No. 10-334879).

According to this structure, the expansion of the positive electrode active material and the accompanying structural looseness of the positive electrode can be suppressed to some extent by the pressing force of the pressing member. In addition, since the pressure member functions as a buffer, the structure of the container does not need to be very strong. But above,
As is evident from the structure in which the pressing member is inserted between the inner surface of the container and the electrode laminate, the pressing force of the pressing member is still generated based on the rigidity of the container, and the container has a lower pressure than before. Anyway, since a certain robust structure is required, the above configuration is not sufficient in terms of weight reduction in particular, in combination with the fact that the pressing member is included in the container.

An object of the present invention is to prevent the deterioration of characteristics due to the permeation of water or an organic solvent, and to prevent the container from being damaged even after repeated charging and discharging. And a battery device using the same.

[0013]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made the container itself a flexible bag without using a rigid structure so that it can flexibly follow expansion and contraction during charging and discharging. At the same time, in order to prevent the loosening of the positive electrode due to the expansion of the positive electrode active material and the accompanying reduction in the cycle life, the container is kept at a constant pressure in the electrode stacking direction of the electrode stack, which is the main expansion direction. As a result of studying the arrangement of the pressing means outside the container instead of inside the container, the present invention has been completed.

That is, in the lithium secondary battery of the present invention, the electrode laminate and the non-aqueous organic electrolyte are placed in a flexible bag-type container capable of preventing the permeation of the organic solvent and water in the electrolyte. It is characterized by being enclosed. Further, the battery device of the present invention is characterized by comprising a pressing means for pressing the lithium secondary battery from the outside so as to apply a constant pressure in the electrode stacking direction of the electrode stack.

According to the present invention having the above-mentioned structure, since a strong and heavy container as in the prior art is not required at all,
The weight of the lithium secondary battery and the battery device using the same can be significantly reduced. In addition, since the bag-type container can prevent both the organic solvent and water from permeating as described above, there is no possibility that the characteristics are deteriorated. If the characteristics are deteriorated, it is only necessary to replace not the entire battery device but only a part of the battery device, that is, a lithium secondary battery that is significantly lighter than the conventional battery device. The pressing means constituting the battery device is, for example, a battery device installation portion provided on a chassis or hood of an electric car or the like, or a battery device installation site provided in advance in a building such as a general home or by remodeling or the like. It may be left without installation or replacement.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 (a) and 1 (b) which show an embodiment of the present invention. Figure
As shown in (a), the battery device of this example is a lithium battery in a hole 1 provided as a battery device installation place under a floor, a wall surface, or an attic of a building such as a general household, a store, and a small factory. After accommodating the secondary battery 2 and the pressing means 3, only the connection terminal 23 of the lithium secondary battery 2 is projected upward, and the hole 1 is covered with the lid 12.

When it is necessary to replace the lithium secondary battery 2, the lid 12 is removed, and only the old lithium secondary battery 2 is pulled out upward as shown by the white arrow in FIG.
After removing it from the inside, you can replace it with a new one.
The lithium secondary battery 2 accommodates the electrode laminate 22 impregnated with the non-aqueous organic electrolyte in the flexible bag-shaped container 21 as described above, and the opening thereof constitutes the electrode laminate 22. In this state, only the connection terminals 23 electrically connected to the respective electrodes are protruded upward and sealed by heat sealing or the like.

In the above-mentioned housed state, the pressing means 3 is inserted into a gap between the side wall surface 11 of the hole 1 and the lithium secondary battery 2. There is provided a flat pressing plate 32 inserted in a gap between the thin leaf spring 31 and the lithium secondary battery 2. Among them, the pressing plate 32 has a function of averaging the pressing force of the thin leaf spring 31, and when the lithium secondary battery 2 is replaced as described above, the bag-shaped container 21 is caught by the thin leaf spring 31. It also works to prevent damage.

Then, the positive electrode active material constituting the electrode laminate 22 of the lithium secondary battery 2 expands by charging and discharging,
When the electrode laminate 22 and, consequently, the lithium secondary battery 2 expands in the direction indicated by the black arrow in the drawing, the pressing force generated in the thin leaf spring 31 due thereto expands via the pressing plate 32. 2 and functions to prevent expansion of the active material of the positive electrode constituting the above-described electrode stack 22 of the lithium secondary battery 2 and the accompanying loosening of the positive electrode.

The bag-shaped container 21 of the lithium secondary battery 2
In order to flexibly follow the expansion and contraction of the electrode laminate 22 during charge and discharge while preventing the deterioration of the characteristics as described above, the organic layer in the non-aqueous organic electrolyte is It is formed of a flexible material that can prevent the permeation of solvent and moisture. Examples of the material forming such a bag-type container include, but are not limited to, a laminate including an olefin-based resin layer excellent in organic solvent permeation prevention properties and a metal layer excellent in water permeation prevention properties. It is preferably used.

As a preferred specific example of the above-mentioned laminate, for example, one having a layer structure shown in FIG. 2 can be mentioned. The laminate shown in the figure has an olefin-based resin layer 21a having excellent organic solvent permeation resistance as described above on the inner side (lower side in the figure) in contact with the organic electrolyte, and a resin adhesive layer 21b on the outer side. Through, excellent thickness of 10-100 μm
Are formed in a four-layer structure in which three metal layers 21c are laminated and a resin surface layer 21d is further laminated on the outside.

Among the above, examples of the olefin resin forming the olefin resin layer 21a include polyethylene and polypropylene. The thickness of the olefin resin layer 21a is not particularly limited,
In consideration of the permeation prevention property of the organic solvent and the flexibility of the bag-shaped container 21, it is preferably about 50 to 90 μm, and more preferably about 65 to 75 μm.

The adhesive layer 21b is used to satisfactorily thermally bond the olefin resin layer 21a and the metal layer 21c. The resin forming the adhesive layer 21b is, for example, polyethylene terephthalate (PET) or the like. Is preferably used. Considering the adhesiveness of the layers 21a and 21c and the flexibility of the bag-type container 21, the thickness of the adhesive layer 21b is preferably about 5 to 20 μm, and more preferably about 10 to 15 μm.

Examples of the metal forming the metal layer 21c include aluminum, nickel, stainless steel, titanium, etc., which have excellent water permeation prevention properties as described above and also have excellent resistance to organic electrolytes. In consideration of the weight reduction of the lithium secondary battery 2 and the battery device in particular, aluminum is particularly preferably used among the above. The thickness of the metal layer 21c is 10 as described above.
It is preferably about 100 μm, especially about 10 μm to 30 μm. If the thickness is less than this range, the water permeation prevention properties may be insufficient, and if it exceeds this range, the flexibility of the bag-shaped container may be reduced.

The surface layer 21d protects the surface of the metal layer 21c and prints the name, trade name, rating, precautionary statement, etc. of the lithium secondary battery 2 and forms the surface layer 21d. As the resin to be used, a polyester-based resin such as PET is also preferably used in consideration of its printability and thermal adhesion to the metal layer 21c. The thickness of the surface layer 21d is determined by considering the function of protecting the surface of the metal layer 21c and the flexibility of the bag-type container 21.
It is preferably about 5 to 20 μm,
More preferably, it is about 5 μm.

In addition, at least one of the resin layers (layers 21a, 21b and 21d) of the layers constituting the above-mentioned laminated body contains, for example, a combination system of hydrotalcite and magnesium sulfate, and water and Lewis acid. It may be contained as a collecting agent to be collected. Further, a resin layer containing a collecting agent for collecting moisture and a Lewis acid may be laminated further inside the innermost olefin resin layer 21a of the laminate. In consideration of the resistance to the organic electrolytic solution, the resin layer is preferably formed of an olefin resin.

When the above-mentioned hydrotalcite and magnesium sulfate are used in combination, the amount of the collector is about 1 to 50 parts by weight based on 100 parts by weight of the resin constituting the layer. Is preferred. If the amount of the collecting agent is less than the above range, the effect of collecting the moisture and Lewis acid may be insufficient due to the addition of the collecting agent. In such a case, the flexibility of the bag-type container 21 may be reduced.

Such a laminate is continuously produced by, for example, a conventionally known heat lamination method. The bag-shaped container is formed by cutting the above-mentioned laminate or the like into a predetermined developed shape, assembling them three-dimensionally, and thermally bonding the joints. As the electrode laminate 22 and the non-aqueous organic electrolytic solution sealed in the formed bag-shaped container 21, any of those similar to conventional lithium secondary batteries can be used.

That is, the electrode laminate 22 is constituted by alternately laminating a plurality of sheet-like positive electrodes and cathodes via a porous separator, and each of the positive electrode and the cathode is a metal foil as a current collector. Is formed by applying a paste containing a powder of a positive electrode active material or a negative electrode active material and a resin binder to one or both surfaces of the substrate and pressing after drying.

As the metal foil, various metal foils having excellent conductivity and excellent resistance to an organic electrolytic solution can be used. Examples of such a metal include aluminum, nickel, copper, stainless steel, titanium, and the like. In view of the performance of the lithium secondary battery 2 in particular, a combination of aluminum for the positive electrode and copper for the negative electrode is preferably used. . The size and shape of the metal foil are appropriately set according to the shape, structure and size of the lithium secondary battery 2.

Examples of the positive electrode active material include a general formula: LiAl _x Co _y Ni _1-xy O ₂ [0 ≦ x ≦ 0.3, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1],
Or a general formula: oxide of a transition metal containing or not containing lithium, such as LiCr _n Mn _2-n O ₄ [0 ≦ n ≦ 2], or sulfide such as iron sulfide,
Selenide and the like. On the other hand, as the negative electrode active material, for example, porous carbon capable of reversibly doping and undoping lithium ions, such as coke, fired resin, carbon fiber, pyrolytic carbon, natural graphite, and mesophase spheres, is preferably used. In addition, an oxide of a transition metal such as Li _4/3 Ti _5/3 O ₄ can also be used.

As the resin binder, for example, fluororesins such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and fluororubber are preferably used because of their excellent resistance to non-aqueous organic electrolytes. You. Examples of the organic electrolyte include an organic solvent such as propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, tetrahydrofuran, or the like.
₄ , a solution in which lithium ions such as LiBF ₄ , LiPF ₆ , and LiAsF ₆ or a solid electrolyte having lithium ion conductivity are dissolved or dispersed is used.

Although only one connection terminal 23 is shown in the figure, it is needless to say that two connection terminals 23 are provided for both positive and negative electrodes. In the case of the drawing, another connection terminal is arranged behind the connection terminal 23 shown in the figure.
In addition, in the bag-shaped container 21, together with the electrode laminate 22, the organic electrolyte, and the connection terminal 23, a collecting agent for collecting water and Lewis acid, such as hydrotalcite or magnesium sulfate, is sealed. You may.

The capacity of the lithium secondary battery 2 provided with each of the above components is not particularly limited. However, the structure of the present invention is not so effective when applied to a small capacity battery having a capacity of less than 50 Ah, for example. An ultra-large battery having a capacity exceeding 1000 Ah in one battery is not easy to manufacture, and is too large to be easily handled, and is not feasible. Therefore, the capacity of one lithium secondary battery 2 is Between these two numbers, ie 50-1000A
It is preferably about h.

In the battery device of the present invention, in order to obtain a higher capacity, two or more lithium secondary batteries 2 may be combined. As the thin leaf spring 31 of the pressing means 3, for example, stainless steel, spring steel,
Any of thin plates made of a hard metal such as titanium formed in a corrugated shape as described above or in various other shapes disclosed in Japanese Patent Application Laid-Open No. 10-334879 can be used. The surface of the thin plate may be covered with a resin such as a fluororesin.

As the pressing plate 32, for example, a resin plate or a metal plate, or a metal plate coated with a resin is used. In addition, as the pressing means 3, in addition to the above, for example, a means in which a pressing plate and a coil spring or a disc spring are combined, or a method in which active parts such as an air cylinder and a motor are combined, although the apparatus is large-scale, is also available. , Is available. Alternatively, the lithium secondary battery 2 is not arranged vertically as shown in the figure, but is arranged horizontally so that the electrodes constituting the electrode stack 22 are oriented horizontally, and a weight as the pressing means 3 is placed thereon. It may be mounted.

Further, as shown in FIG. 3, the above-described lithium secondary battery 2 may be housed in a box 4 having a slightly larger inner dimension or in a hole, to form a battery device. In this case, since the box 4 itself or the hole itself functions as a pressing means for suppressing the expansion of the electrode laminate 22 due to its rigidity, the structure is the simplest. Moreover, in this case as well, only the lightweight lithium secondary battery 2 needs to be replaced, so that replacement is easy when the characteristics of the battery are deteriorated. In the case of, for example, an electric vehicle, the portion serving as the box 4 may be incorporated in the structure of the chassis or body in advance, so that the weight can be reduced.

Various other design changes can be made without changing the gist of the present invention.

[0039]

The present invention will be described below based on examples and comparative examples. Example 1 <Production of bag-shaped container> The thickness was 70 μm by a heat lamination method.
m polypropylene layer 21a and 12 μm thick PE
T adhesive layer 21b and 20 μm thick aluminum layer 2
1c and a 12 μm-thick PET surface layer 21d were laminated in this order to produce a four-layer laminate having the layer configuration shown in FIG.

The laminate was cut into a predetermined developed shape and assembled into a three-dimensional shape such that the polypropylene layer 21a was on the inside.
(a) It is approximately box-shaped as shown in (b), and is 20 cm long, 21 cm wide,
A bag-type container 21 having a height of 25 cm was prepared. <Preparation of positive electrode> LiCoO ₂ powder 1 as positive electrode active material
00 parts by weight, 10 parts by weight of graphite, PVdF10
Parts by weight, and N-methyl-2-pyrrolidone was added to form a paste.
mm aluminum foil on both sides and dried. Then roll cut and cut, 0.18m thick
m, a positive electrode having a length of 200 mm and a width of 200 mm was prepared.

<Preparation of Negative Electrode> 20 parts by weight of PVdF was mixed with 100 parts by weight of flaky natural graphite powder as an anode active material, and N-methyl-2-pyrrolidone was added to form a paste. It was applied to both sides of a copper foil of 0.02 mm and dried. Then roll cut and then cut, thickness 0.28mm, length 200mm, width 2
A 00 mm negative electrode was produced.

<Manufacture of Lithium Secondary Battery> The positive electrode and the negative electrode prepared as described above were
m, 200 mm wide polypropylene microporous membrane as separator, positive electrode-separator-negative electrode-separator -...
The electrode laminate 22 was obtained by laminating a total of 360 sheets in this order.
Next, when the electrode laminate 22 was accommodated in the bag-shaped container 21, a mixture of ethylene carbonate and diethyl carbonate at a volume ratio of 1: 1 was added as an electrolyte to Li.
PF ₄ dissolved non-aqueous organic electrolyte (electrolyte concentration 1
M) and injected under reduced pressure of 400 mmHg for 96 hours,
After the impregnation, the positive electrode constituting the electrode laminate 22 is provided with a positive connection terminal 23 and the negative electrode is provided with a negative connection terminal 23.
Were connected respectively.

Finally, the mouth of the bag-shaped container 21 was sealed by heat sealing with the connection terminals 23 protruding upward, whereby a lithium secondary battery 2 was manufactured. The capacity of the obtained lithium secondary battery 2 was 400 Ah, and the weight was 13.
It was 7 kg. <Structure of Battery Device and Battery Characteristics Test> The lithium secondary battery 2 manufactured above was formed of an aluminum plate having a thickness of 4 mm and also serving as a pressing means.
The battery device was housed in a box body 4 cm, 21 cm wide and 25 cm deep.

In this battery device, the above-mentioned lithium secondary battery 2 was supplied with an initial current density of 0.15 mA / c.
After charging at a constant current and a constant voltage for 8 to 10 hours under charging conditions of m ² and an upper limit voltage of 4.1 V, the current density was 0.15 mA / c.
The cycle of constant current discharge to 3.0 V under the discharge condition of m ² was repeated, and the number of cycles at which the capacity became 70% of the initial capacity was determined as the life of the battery.

In the eighth cycle of the above cycle, the maximum capacity measured by discharging the battery at a current density of 0.2 mA / cm ² and the weight of the lithium secondary battery 2 described above were used to determine the lithium secondary battery 2. When I calculated the energy density,
It was 105 Wh / kg. Example 2 Layer 2 of polypropylene in the laminate forming a bag-type container
In the same manner as in Example 1 except that a layer of 50 μm thick polyethylene containing hydrotalcite and magnesium sulfate, each containing 10 parts by weight with respect to 100 parts by weight of polyethylene, was further laminated inside 1a. A lithium secondary battery 2 was manufactured.

The capacity of the obtained lithium secondary battery 2 is 40
The weight was 0 Ah and the weight was 13.8 kg. Further, a battery device was constructed by combining the lithium secondary battery 2 with a box 4 having the same dimensions as above, and the life of the battery was determined by charging and discharging the lithium secondary battery 2 under the same conditions as above. 680 cycles.

In the same manner as described above, the lithium secondary battery 2
Was 104 Wh / kg. Example 3 The same lithium secondary battery 2 produced in Example 1 was used instead of the box body 4 and was formed under the floor of a building. The inner dimensions were 20 cm in length, 21 cm in width, and 25 cm in depth. Example 1 except that was combined with a hole covered with concrete
In this state, the lithium secondary battery 2 was charged and discharged under the same conditions as above to determine the life of the battery. As a result, it was 500 cycles.

Example 4 As a laminate forming a bag-type container, the adhesive layer was omitted,
In order from the inside of the container, a layer of polypropylene having a thickness of 70 μm, a layer of aluminum having a thickness of 20 μm, and a layer having a thickness of 12 μm
A lithium secondary battery 2 was manufactured in the same manner as in Example 1 except that a three-layer structure in which a m layer of PET was laminated was used.

The capacity, weight and energy density of the obtained lithium secondary battery 2 were the same as in Example 1. Further, a battery device is configured by combining the lithium secondary battery 2 with a box body 4 having the same dimensions as the above, and the lithium secondary battery 2
Was charged and discharged under the same conditions as above, and the life of the battery was determined. The result was 250 cycles.

Example 5 As a laminate forming a bag-type container, a 70 μm-thick polypropylene layer and a 12 μm-thick
lithium secondary battery 2 in the same manner as in Example 1 except that a four-layer structure in which an adhesive layer of PET having a thickness of m, a layer of aluminum having a thickness of 9 μm, and a surface layer of PET having a thickness of 12 μm were laminated was used. Was manufactured.

The capacity, weight and energy density of the obtained lithium secondary battery 2 were the same as in Example 1. Further, a battery device is configured by combining the lithium secondary battery 2 with a box body 4 having the same dimensions as the above, and the lithium secondary battery 2
Was charged and discharged under the same conditions as above, and the life of the battery was determined. The result was 160 cycles.

COMPARATIVE EXAMPLE 1 The same electrode laminate 22 produced in Example 1 was placed in a rigid battery container formed of an aluminum plate having a thickness of 4 mm and having inner dimensions of 20 cm in length, 21 cm in width and 25 cm in depth. Containing, injecting the same non-aqueous organic electrolyte solution as described above, and impregnating under a reduced pressure of 400 mmHg for 96 hours, and then connecting the positive electrode connecting terminal 23 to each positive electrode constituting the electrode laminate 22; The connection terminal 23 for a negative electrode was connected to the negative electrode, respectively. Then, with the connection terminal 23 protruding upward, the container was sealed with a lid made of an aluminum plate in which only the connection terminal portion was insulated with resin, thereby manufacturing a lithium secondary battery having a conventional structure.

The capacity of the obtained lithium secondary battery was the same as in Example 1. Further, the lithium secondary battery was charged and discharged under the same conditions as above to determine the life of the battery.
40 cycles. The weight of the lithium secondary battery was 20.6 kg. Based on this weight, the energy density of the lithium secondary battery was determined in the same manner as described above, and it was 70 Wh / kg.

Comparative Example 2 As a laminate forming a bag-type container, the polypropylene layer was omitted, and a 12 μm-thick PE was sequentially arranged from the inside of the container.
A layer of T, a layer of aluminum having a thickness of 20 μm,
A lithium secondary battery 2 was manufactured in the same manner as in Example 1, except that a three-layer structure in which a 2 μm PET surface layer was laminated was used.

The capacity, weight and energy density of the obtained lithium secondary battery 2 were the same as in Example 1. Further, a battery device is configured by combining the lithium secondary battery 2 with a box body 4 having the same dimensions as the above, and the lithium secondary battery 2
Was charged and discharged under the same conditions as above, and the life of the battery was determined. The result was 70 cycles.

Table 1 summarizes the above results.

[0057]

[Table 1]

From the table, it was found that, according to Examples 1 to 5, the weight can be reduced and the energy density can be improved as compared with Comparative Example 1 which is a battery having a conventional structure. Further, from the results of each of Examples and Comparative Example 2, the laminated body forming the bag-shaped container has a layer structure capable of preventing both the transmission of the organic solvent in the electrolytic solution and the moisture, that is, in this case, the organic layer. It was found that a material having both a layer of polypropylene having excellent solvent permeability and an aluminum layer having excellent water permeability was preferred. Furthermore, from the comparison of the examples, among the above, the thickness of the aluminum layer was 1
At least 0 μm, it is preferable to be able to more reliably prevent the permeation of water and the volatilization of the organic solvent from the pinhole, and in particular, a polypropylene layer and an aluminum layer, which are thermally bonded with a PET bonding layer, are more preferable. It turned out to be favorable.

[0059]

As described in detail above, according to the present invention,
This has a specific effect that a large-sized lithium secondary battery which is significantly lighter than before and a battery device using the same can be provided.

[Brief description of the drawings]

FIG. 1 (a) is a cross-sectional view showing an example of an embodiment of a battery device of the present invention, and FIG. 1 (b) shows a lithium secondary battery through a hole for replacement in the above example. It is sectional drawing which shows the state pulled out.

FIG. 2 is a cross-sectional view illustrating an example of a layer configuration of a laminate forming a bag-type container of a lithium secondary battery in the battery device of the above example.

FIG. 3 is a cross-sectional view showing, as another example of the embodiment of the battery device of the present invention, a state in which a lithium secondary battery is combined with a box also serving as a pressing means.

[Explanation of symbols]

 2 Lithium secondary battery 22 Electrode laminate 21 Bag type container 3 Pressing means 4 Box (also serving as pressing means)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Ujiie 3-3-22 Nakanoshima, Kita-ku, Osaka Kansai Electric Power Co., Inc. (72) Eriko Yagasaki 3-2-2, Nakanoshima, Kita-ku, Osaka Kansai F-term (Reference) 5H011 AA01 AA02 AA09 AA10 AA13 CC02 CC06 CC10 KK00 KK01 5H029 AJ02 AJ05 AJ07 AJ11 AJ12 AJ14 AK03 AK05 AL03 AL06 AL07 AM03 AM04 AM05 AM07 BJ02 BJ11 DJ04

Claims (8)

[Claims] 1. An electrode laminate and a non-aqueous organic electrolytic solution,
A lithium secondary battery, which is sealed in a flexible bag-shaped container capable of preventing permeation of an organic solvent and moisture in the electrolytic solution. 2. The bag-shaped container is formed of a laminate including a layer of an olefin-based resin having excellent organic solvent permeability and a metal layer having excellent water permeability.
The lithium secondary battery as described in the above. 3. A laminated body forming a bag-type container has an olefin-based resin layer in contact with an organic electrolytic solution, and a metal layer having a thickness of 10 to 100 μm on the outside thereof via a resin adhesive layer. 3. The lithium secondary battery according to claim 2, which has at least a three-layer structure. 4. The lithium secondary battery according to claim 3, wherein a collecting agent for collecting moisture and Lewis acid is contained in one of the resin layers forming the bag-type container. 5. The laminate according to claim 3, further comprising a resin layer containing a trapping agent for trapping moisture and Lewis acid, further inside the olefin resin layer in the laminate forming the bag-type container. Lithium secondary battery. 6. The lithium secondary battery according to claim 1, wherein a collecting agent for collecting moisture and Lewis acid is sealed in the bag-shaped container together with the electrode laminate and the organic electrolyte. 7. The battery according to claim 1, wherein the capacity is 50 to 1000 Ah.
The lithium secondary battery as described in the above. 8. A battery device, comprising: pressing means for pressing the lithium secondary battery according to claim 1 from outside thereof so as to apply a constant pressure in the electrode stacking direction of the electrode stack.