JP6801722B2 - Rechargeable batteries, battery packs, electric vehicles, power storage systems, power tools and electronics - Google Patents

Description

The present technology relates to a secondary battery using a film-like exterior member, and a battery pack, an electric vehicle, a power storage system, an electric tool, and an electronic device using the secondary battery.

Various electronic devices such as mobile phones and personal digital assistants (PDAs) are widely used, and there is a demand for miniaturization, weight reduction, and long life of the electronic devices. Therefore, as a power source, a battery, particularly a secondary battery which is small and lightweight and can obtain a high energy density, is being developed.

The secondary battery is not limited to the above-mentioned electronic devices, and its application to other applications is also being considered. Examples include battery packs that are detachably mounted on electronic devices, electric vehicles such as electric vehicles, power storage systems such as household power servers, and power tools such as electric drills.

The laminated film type secondary battery is a secondary battery using a film-like exterior member. In the laminated film type secondary battery, the battery element is housed inside the film-shaped exterior member, and the battery element contains a positive electrode, a negative electrode, an electrolytic solution, and the like.

Since the film-shaped exterior member has flexibility, it has a property of being easily deformed in response to an external force. For this reason, in a laminated film type secondary battery, when gas is generated inside the secondary battery, the secondary battery tends to swell due to deformation of the film-like exterior member.

Various studies have been made to prevent the secondary battery from swelling in this way. Specifically, in order to release the gas generated inside the secondary battery to the outside, a safety valve or the like is provided on the film-shaped exterior member (see, for example, Patent Documents 1 to 4).

Japanese Unexamined Patent Publication No. 2007-087922 JP-A-2007-157678 JP-A-2007-265725 Japanese Unexamined Patent Publication No. 2014-211994

Electronic devices and the like are becoming more sophisticated and multifunctional. For this reason, the frequency of use of electronic devices and the like is increasing, and the usage environment of the electronic devices and the like is expanding. Therefore, there is still room for improvement in battery characteristics including the swelling characteristics of the secondary battery.

Therefore, it is desirable to provide secondary batteries, battery packs, electric vehicles, power storage systems, power tools and electronic devices capable of obtaining excellent battery characteristics.

The secondary battery of one embodiment of the present invention includes a battery element containing a positive electrode, a negative electrode, and an electrolytic solution, and a film-like exterior member that houses the battery element and has a window portion containing a non-porous molten fluororesin. The exterior member has an opening, and a single-layer film-like window member containing a non-porous molten fluororesin covers the opening to form the window portion. It has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member .

Each of the battery pack, the electric vehicle, the power storage system, the electric tool, and the electronic device of the embodiment of the present technology includes a secondary battery, and the secondary battery is the secondary battery of the above-described embodiment of the present technology. It has a similar configuration.

Here, the "window portion" is a part of the film-shaped exterior member, and is exposed to each of the internal environment in which the battery element is housed and the external environment in which the battery element is not housed. The internal environment is the internal environment of the film-like exterior member, and the external environment is the external environment of the film-like exterior member.

According to the secondary battery of an embodiment of the present technology, the internal and the battery element is accommodated in a film package member, together with the window containing the molten fluororesin nonporous are provided in the outer member A single-layer film-like window member containing the non-porous molten fluororesin covers the opening of the exterior member to form the window, and the window member has an area larger than the area of the opening. Is arranged inside the exterior member so that it is attached to the exterior member via an adhesive, so that excellent battery characteristics can be obtained. Further, the same effect can be obtained in the battery pack, the electric vehicle, the electric power storage system, the electric tool or the electronic device of one embodiment of the present technology.

The effects described here are not necessarily limited, and may be any of the effects described in the present technology.

It is a perspective view which shows the structure (state before bonding of exterior members) of the secondary battery of 1st Embodiment of this technique. It is a perspective view which shows the other structure (state after bonding of the exterior member) of the secondary battery shown in FIG. It is sectional drawing which shows the structure of the exterior member along the line AA shown in FIG. It is sectional drawing which shows the structure of the wound electrode body along the line BB shown in FIG. It is a perspective view for demonstrating the 1st modification concerning the structure of a secondary battery. It is a perspective view for demonstrating the 2nd modification which concerns on the structure of the secondary battery. It is a perspective view for demonstrating the 3rd modification which concerns on the structure of a secondary battery. It is a perspective view which shows the structure (state after bonding of exterior members) of the secondary battery of 2nd Embodiment of this technique. It is sectional drawing which shows the structure of the exterior member along the line CC shown in FIG. It is sectional drawing which shows the structure of the exterior member along the DD line shown in FIG. It is a perspective view which shows the structure of the application example (battery pack: cell) of a secondary battery. It is a block diagram which shows the structure of the battery pack shown in FIG. It is a block diagram which shows the structure of application example (battery pack: assembled battery) of a secondary battery. It is a block diagram which shows the structure of the application example (electric vehicle) of a secondary battery. It is a block diagram which shows the structure of the application example (power storage system) of a secondary battery. It is a block diagram which shows the structure of the application example (power tool) of a secondary battery.

Hereinafter, one embodiment of the present technology will be described in detail with reference to the drawings. The order of explanation is as follows.

1. 1. Secondary battery (first embodiment)
1-1. Lithium-ion secondary battery 1-2. Lithium metal secondary battery 1-3. Modification example 2. Secondary battery (second embodiment)
2-1. Lithium-ion secondary battery 2-2. Lithium metal secondary battery 2-3. Modification example 3. Applications of secondary batteries 3-1. Battery pack (cell)
3-2. Battery pack (assembled battery)
3-3. Electric vehicle 3-4. Power storage system 3-5. Electric tool

<1. Secondary battery (first embodiment)>
First, the secondary battery of the first embodiment will be described.

<1-1. Lithium-ion secondary battery ＞
The secondary battery described here is, for example, a lithium ion secondary battery in which the capacity of the negative electrode can be obtained by occlusion and release of lithium, which is an electrode reactant.

Each of FIG. 1 and FIG. 2 represents a perspective configuration of the secondary battery of the present embodiment. However, FIG. 1 shows the state of the exterior member 40 before bonding, and the wound electrode body 30 and the exterior member 40 are separated from each other. FIG. 2 shows a state after the exterior members 40 are bonded together.

FIG. 3 shows the cross-sectional configuration of the exterior member 40 along the line AA shown in FIG. FIG. 4 shows a cross-sectional configuration of the wound electrode body 30 along the line BB shown in FIG.

[overall structure]
This secondary battery is a laminated film type secondary battery using a film-shaped exterior member 40. In the laminated film type secondary battery, for example, as shown in FIGS. 1 to 3, the wound electrode body 30 which is a battery element is housed inside the exterior member 40 having the window portion 42. The details of the window portion 42 will be described later.

In the wound electrode body 30, for example, as shown in FIG. 4, after the positive electrode 33 and the negative electrode 34 are laminated via the separator 35 and the electrolyte layer 36, the positive electrode 33, the negative electrode 34, the separator 35 and the electrolyte layer 36 are laminated. Is wound around. That is, the wound electrode body 30 housed inside the exterior member 40 includes a positive electrode 33, a negative electrode 34, and an electrolyte layer 36, and the electrolyte layer 36 contains an electrolytic solution described later. The outermost peripheral portion of the wound electrode body 30 is protected by, for example, a protective tape 37.

A positive electrode lead 31 is attached to the positive electrode 33, and the positive electrode lead 31 is led out from the inside of the exterior member 40 to the outside. The positive electrode lead 31 contains any one or more of the conductive materials such as aluminum (Al). The shape of the conductive material is not particularly limited, but is, for example, a thin plate or a mesh.

A negative electrode lead 32 is attached to the negative electrode 34, and the negative electrode lead 32 is led out from the inside of the exterior member 40 to the outside. The negative electrode lead 32 contains any one or more of conductive materials such as copper (Cu), nickel (Ni) and stainless steel. The shape of the conductive material is the same as that described with respect to the positive electrode lead 31, for example.

In FIG. 2, the positive electrode lead 31 and the negative electrode lead 32 are not shown. As is clear from FIG. 1, for example, each of the positive electrode lead 31 and the negative electrode lead 32 is led out in the same direction from the inside to the outside of the exterior member 40.

[Exterior member]
As described above, the exterior member 40 houses the wound electrode body 30. Since the exterior member 40 is in the form of a film, it has flexibility.

In particular, the exterior member 40 includes, for example, the exterior main body 41 provided with the window portion 42 described above, as shown in FIGS. 1 to 3.

(Exterior body)
The exterior body 41 is the body of the exterior member 40 and is a film-like member. The configuration of the exterior body 41 is not particularly limited, but the exterior body 41 is, for example, a multilayer film (laminated film) including an adhesive layer.

Specifically, the exterior body 41 is, for example, a laminated film in which an adhesive layer, a metal layer, and a surface protective layer are laminated in this order from the inside. In this case, for example, the wound electrode body 30 is housed inside the exterior member 40 by adhering the adhesive layers of the exterior body 41 to each other via the wound electrode body 30.

When the heat fusion method is used as the bonding method, the bonding layer is, for example, a fusion layer. The fused layer is a film containing any one or more of polymer compounds such as polyethylene and polypropylene. The metal layer is, for example, a metal leaf containing any one or more of metal materials such as aluminum. The surface protective layer is a film containing any one or more of polymer compounds such as nylon and polyethylene terephthalate.

Above all, it is preferable that the exterior main body 41 is, for example, an aluminum laminated film in which a polyethylene film, an aluminum foil, and a nylon film are laminated in this order in order from the inside. This is because sufficient adhesiveness and sufficient airtightness can be obtained.

For example, as shown in FIGS. 1 to 3, the exterior body 41 includes an exterior portion 41A which is a first exterior member that covers the wound electrode body 30 from one side (here, above), and the wound electrode body thereof. It includes an exterior portion 41B, which is a second exterior member that covers 30 from the other side (here, from below). The forming material of the exterior portion 41A and the forming material of the exterior portion 41B may be the same as each other or may be different from each other.

In this case, for example, in a state where the wound electrode body 30 is sandwiched between the exterior portions 41A and 41B, a part of the exterior portion 41A and a part of the exterior portion 41B are adhered to each other. The wound electrode body 30 is housed inside the exterior member 40. A part of the exterior portion 41A is, for example, an outer edge portion of the exterior portion 41A, and a part of the exterior portion 41B is, for example, an outer edge portion of the exterior portion 41B.

Along with this, the exterior body 41 seals the non-adhesive region 41X in which the exterior portions 41A and 41B are not adhered to each other and the exterior member 40 in order to house the wound electrode body 30 inside the exterior member 40. Therefore, the exterior portions 41A and 41B include an adhesive region 41Y that is adhered to each other. For example, as shown in FIGS. 1 and 2, the adhesive region 41Y is the outer edge region of each of the exterior portions 41A and 41B, and the non-adhesive region 41X is the outer edge region of each of the exterior portions 41A and 41B. It is an area other than the outer edge area (the central area surrounded by the outer edge area).

The exterior portions 41A and 41B may be separated from each other or may be connected (integrated) with each other, for example. When the exterior portions 41A and 41B are separated from each other, the exterior main body 41 is, for example, two films. On the other hand, when the exterior portions 41A and 41B are connected to each other, the exterior main body 41 is, for example, one film.

Here, for example, since the exterior portions 41A and 41B are connected to each other, the exterior main body 41 is a single film. This one film may be originally one film, or may be a composite film in which two films are connected. Along with this, the exterior body 41 can be folded in the direction of the arrow R shown in FIG. 1, for example. In this case, since the exterior body 41 is folded, the exterior portion 41A covers the wound electrode body 30 from above and the exterior portion 41B covers the wound electrode body 30 from below, as described above. The wound electrode body 30 is housed inside the exterior member 40.

The exterior portion 41A is provided with, for example, a recessed portion 41P for accommodating the wound electrode body 30. Along with this, the exterior portion 41A partially protrudes outward, for example, at a portion where the recess portion 41P is provided. The fact that the recessed portion 41P is provided in the exterior portion 41A facilitates the alignment of the wound electrode body 30 with respect to the exterior body 41 and facilitates the storage of the wound electrode body 30 inside the exterior member 40. Because.

In a state where the wound electrode body 30 is housed inside the exterior member 40, for example, an adhesive film 50 is used to seal the exterior member 40. Specifically, for example, the adhesion film 50 is inserted between the exterior body 41 (exterior portions 41A and 41B) and the positive electrode lead 31, and similarly, the adhesion film is inserted between the exterior body 41 and the negative electrode lead 32. 50 is inserted.

The adhesive film 50 contains any one or more of the adhesive materials in order to prevent outside air from entering the exterior member 40. The adhesive material is a material having adhesiveness to each of the positive electrode lead 31 and the negative electrode lead 32, and is, for example, a polyolefin resin. The type of the polyolefin resin is not particularly limited, and examples thereof include polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

(Window)
The window portion 42 mainly fulfills a function of suppressing water from entering the inside of the exterior member 40 (waterproof function), and also has a function of discharging gas generated inside the exterior member 40 to the outside (a function of discharging the gas generated inside the exterior member 40 to the outside). Exhaust function). The water described here is, for example, water and water vapor existing outside the secondary battery. Further, the gas is, for example, carbon dioxide gas (carbon dioxide) generated due to a side reaction such as a decomposition reaction of an electrolytic solution.

As described above, the window portion 42 is a part of the exterior member 40 and is exposed to each of the internal environment E1 and the external environment E2 as shown in FIG.

The internal environment E1 is an environment in which the wound electrode body 30 is housed (the environment inside the exterior member 40). Therefore, the internal environment E1 is formed by accommodating the wound electrode body 30 inside the exterior member 40. On the other hand, the external environment E2 is an environment in which the wound electrode body 30 is not housed (the environment outside the exterior member 40). That is, the window portion 42 releases gas from the internal environment E1 to the external environment E2 while suppressing water from entering the internal environment E1 from the external environment E2.

The exterior member 40 (exterior body 41) has the window portion 42 because the window portion 42 uses the waterproof function of the window portion 42 to suppress deterioration of cycle characteristics and the like due to water. This is to suppress the swelling of the secondary battery by utilizing the exhaust function of. In this case, since it is not necessary to use a machine such as a safety valve, an instrument, a device, or the like, deterioration of cycle characteristics and the like can be easily suppressed, and swelling of the secondary battery can be easily suppressed.

The number, position, and configuration of the window portions 42 are not particularly limited as long as the above-mentioned waterproof function and exhaust function can be exhibited.

Specifically, the number of the window portions 42 may be only one or two or more. Here, the number of windows 42 is, for example, one.

Further, the position of the window portion 42 may be arbitrary. Here, the window portion 42 is provided, for example, in the recessed portion 41P of the exterior main body 41 (exterior portion 41A). More specifically, for example, when the recessed portion 41P has one upper surface 41PT and four side surfaces 41PS, the window portion 42 is provided on the upper surface 41PT.

That is, the window portion 42 is provided, for example, in the non-adhesive region 41X of the exterior main body 41.

Further, for example, the exterior main body 41 is provided with an opening 41K, and the window film 43, which is a film-like window member, covers (closes) the opening 41K to form the window 42. That is, the window portion 42 contains, for example, a window functional material (non-porous molten fluororesin) described later and a window film 43 that closes the opening 41K. In each of FIGS. 1 and 2, the window portion 43 is shaded in order to make it easier to identify the window film 43.

The opening 41K is a through hole for communicating the internal environment E1 and the external environment E2 with each other. Since the opening shape of the opening 41K is not particularly limited, for example, it may be circular, elliptical, rectangular, or other shape. Here, the opening shape of the opening 41K is, for example, an ellipse. Since the size (area) of the opening 41K is not particularly limited, it can be arbitrarily set.

The window film 43 is a film having each of the above-mentioned waterproof function and exhaust function. Along with this, the window film 43 contains a window functional material. The "window functional material" is a material capable of suppressing water from entering the exterior member 40 from the outside and releasing gas from the inside of the exterior member 40 to the outside. More specifically, the window function material is a material that functions as a barrier film that does not sufficiently permeate water in order to ensure the waterproof function, and also sufficiently supplies a gas such as carbon dioxide to ensure the exhaust function. It is a material having gas permeability that can be permeated into. That is, the window functional material is a material having selective permeability with respect to water and gas.

This window functional material contains any one or more of the non-porous molten fluororesins. This non-porous molten fluororesin is a general term for fluororesins that do not have one or more pores and have meltability to the extent that they can be melt-processed and melt-molded. ..

The type of the non-porous molten fluororesin is not particularly limited, and for example, a non-porous tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) or a non-porous tetrafluoroethylene / hexafluoropropylene copolymer (PFA) FEP) and fluoropolymer compounds such as non-porous tetrafluoroethylene-ethylene copolymer (ETFE). This is because these specific types of fluoropolymer compounds can sufficiently exert each of the above-mentioned waterproof function and exhaust function.

It should be noted that the non-fluorine-based polymer compounds such as polyethylene terephthalate (PET) and polypropylene (PP) have too low selective permeability for water and gas as compared with the molten fluororesin, and therefore have a high non-fluorine-based polymer compound. The molecular compound cannot exhibit both the waterproof function and the exhaust function described above. Further, even if the porous PFA, the porous FEP, the porous ETFE and the like correspond to the molten fluororesin, since they are porous, they cannot exhibit both the waterproof function and the exhaust function described above.

Here, whether or not the polymer compound is non-porous can be confirmed by, for example, the following procedure. Specifically, after obtaining a film of a polymer compound, the cross section of the film is observed using an electron microscope or the like. The magnification at the time of observation can be set arbitrarily. As a result, when one or more pores are observed inside the film, the polymer compound forming the film is porous. Since the state of the pores is not particularly limited, it may be, for example, a substantially circular void or a tubular path extending in a predetermined direction. On the other hand, when one or more pores are not observed inside the film, the polymer compound forming the film is non-porous.

Since the planar shape of the window film 43 is not particularly limited, it may be, for example, a circular shape, an elliptical shape, a rectangular shape, or any other shape. That is, the planar shape of the window film 43 may be the same as the opening shape of the opening 41K, or may be different from the opening shape of the opening 41K. Here, the planar shape of the window film 43 is, for example, the same as the opening shape of the opening 41K. Therefore, the planar shape of the window film 43 is, for example, an ellipse.

As long as the window film 43 can close the opening 41K, the size (area) of the window film 43 is not particularly limited. That is, the area of the window film 43 may be the same as the opening area of the opening 41K, or may be larger than the opening area of the opening 41K.

Above all, since the window film 43 contains a window functional material (non-porous molten fluororesin), the area of the window film 43 is preferably larger than the area of the opening 41K. This is because the window film 43 can be attached to the exterior body 41 by using an adhesive in order to fix the window film 43 to the exterior body 41.

Specifically, for example, as shown in FIG. 3, since the area of the window film 43 is larger than the area of the opening 41K, the window film 43 is an adhesive so as to close the opening 41K. It is attached to the exterior body 41 via 44. The window film 43 containing the non-porous molten fluororesin generally has another object (here, the exterior body 41) due to the adhesive resistance peculiar to the non-porous molten fluororesin. It has the property of being difficult to adhere to. However, by selecting an adhesive 44 having excellent compatibility (adhesiveness) with the non-porous molten fluororesin, the window film 43 can be sufficiently adhered to the exterior body 41 using the adhesive 44. ..

The installation position of the window film 43 is not particularly limited. Therefore, the window film 43 may be arranged inside the exterior body 41 (internal environment E1) or outside the exterior body 41 (external environment E2).

Above all, as shown in FIG. 3, the window film 43 is preferably arranged inside the exterior main body 41. This is because even if gas is generated inside the secondary battery, the window film 43 is prevented from being unintentionally peeled off and dropped off. The window film 43 is adhered to the inner surface of the exterior body 41 via, for example, an adhesive 44.

Specifically, when gas is generated inside the secondary battery, the window film 43 is pushed from the internal environment E1 toward the external environment E2 due to the increase in the internal pressure. In this case, for example, as described later, if the window film 43 is arranged outside the exterior body 41 (see FIG. 6), the window film 43 is located in the external environment E2 from the beginning, and the window thereof. There is nothing on the outside of the film 43. Therefore, depending on how the internal pressure rises, if the adhesive 44 peels off from one or both of the exterior body 41 and the window film 43, the window film 43 may peel off from the exterior body 41. Further, when the window film 43 is peeled off from the exterior main body 41, the window film 43 may fall off from the secondary battery.

On the other hand, when the window film 43 is arranged inside the exterior body 41 (see FIG. 3), the window film 43 is located in the internal environment E1 and the exterior body 41 is outside the window film 43. Existing. In this case, the window film 43 is pressed by the exterior body 41 so as to stay in the internal environment E1 at a place where the window film 43 and the exterior body 41 overlap each other. Therefore, the adhesive 44 is difficult to peel off from each of the exterior body 41 and the window film 43, so that the window film 43 is hard to peel off from the exterior body 41. Further, even if the window film 43 is peeled off from the exterior body 41 due to an increase in the internal pressure, the window film 43 is still likely to exist in the internal environment E1, so that the window film 43 is unlikely to fall off from the secondary battery. Become.

The thickness of the window film 43 is not particularly limited, but is, for example, 10 μm to 500 μm, preferably 10 μm to 200 μm. By using the window film 43 containing the window functional material (non-porous molten fluororesin), a sufficient waterproof function and a sufficient exhaust function can be obtained while ensuring the physical durability of the window film 43. is there.

Specifically, when the thickness of the window film 43 is smaller than 10 μm, the window film 43 is too thin, so that the window film 43 easily releases gas when gas is generated, but the window film 43 releases water. In addition to being easy to pass through, the window film 43 may be easily deformed, broken, and peeled off when the internal pressure rises. On the other hand, if the thickness of the window film 43 is larger than 500 μm, the window film 43 is too thick, so that the window film 43 is less likely to be deformed, damaged or peeled off even when the internal pressure rises, and the window film 43 becomes difficult to peel off. While it becomes difficult for water to pass through, the window film 43 may have difficulty in releasing gas.

The adhesive 44 contains, for example, any one or more of polymer compounds (adhesive materials) such as polyolefin resins, epoxy resins, urethane resins, cyanoacrylates and styrene-butadiene rubbers. The polyolefin resin is, for example, polypropylene (PP) or the like.

Since the state of the adhesive 44 before bonding is not particularly limited, it may be in the form of powder, liquid, film, or a mixture of two or more of them. However, in order to make the thickness of the adhesive 44 uniform and to suppress the occurrence of pinholes in the adhesive 44, the state of the adhesive 44 before bonding is either liquid or film. It is preferably one or both.

If the adhesiveness between the adhesive 44 and the window film 43 is not sufficient, for example, in order to improve the adhesiveness, one or more of the pretreatments are applied to the surface of the window film 43. May be applied. The type of this pretreatment is not particularly limited, and includes, for example, chemical treatment, corona treatment, and ultraviolet irradiation (UV) treatment. Above all, chemical treatment is preferable. This is because the adhesiveness between the window film 43 and the adhesive 44 can be easily improved without using equipment such as a heat source and a light source.

Of course, even when the adhesiveness between the adhesive 44 and the exterior body 41 is not sufficient, for example, in order to improve the adhesiveness as in the case where the adhesiveness between the adhesive 44 and the window film 43 is not sufficient. The surface of the exterior body 41 may be subjected to any one or more of the pretreatments. Details regarding the pretreatment are as described above, for example.

[Positive electrode]
The positive electrode 33 includes, for example, as shown in FIG. 4, a positive electrode current collector 33A and a positive electrode active material layer 33B provided on both sides of the positive electrode current collector 33A. However, the positive electrode active material layer 33B may be provided on only one side of the positive electrode current collector 33A.

The positive electrode current collector 33A contains, for example, any one or more of the conductive materials. The type of the conductive material is not particularly limited, and is, for example, a metal material such as aluminum, nickel, and stainless steel. The positive electrode current collector 33A may be a single layer or a multilayer.

The positive electrode active material layer 33B contains, as the positive electrode active material, any one or more of the positive electrode materials capable of occluding and releasing lithium. However, the positive electrode active material layer 33B may further contain any one or more of other materials such as a positive electrode binder and a positive electrode conductive agent.

The positive electrode material is preferably a lithium-containing compound, and more specifically, one or both of a lithium-containing composite oxide and a lithium-containing phosphoric acid compound. This is because a high energy density can be obtained.

The lithium-containing composite oxide is an oxide containing lithium and one or more other elements (elements other than lithium) as constituent elements, and is, for example, one of a layered rock salt type and a spinel type. It has a crystal structure. The lithium-containing phosphoric acid compound is a phosphoric acid compound containing lithium and one or more other elements as constituent elements, and has a crystal structure such as an olivine type.

The type of the other element is not particularly limited as long as it is any one type or two or more types of any element. Among them, the other element is preferably any one or more of the elements belonging to groups 2 to 15 in the long periodic table. More specifically, the other element may contain one or more metal elements of nickel (Ni), cobalt (Co), manganese (Mn) and iron (Fe). preferable. This is because a high voltage can be obtained.

The lithium-containing composite oxide having a layered rock salt type crystal structure is, for example, a compound represented by each of the following formulas (21) to (23).

Li _a Mn _(1-bc) Ni _b M11 _c O _{(2-d) Fe} ... (21)
(M11 is cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc. (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W). A to e are 0.8. ≦ a ≦ 1.2, 0 <b <0.5, 0 ≦ c ≦ 0.5, (b + c) <1, −0.1 ≦ d ≦ 0.2 and 0 ≦ e ≦ 0.1 are satisfied. However, the composition of lithium differs depending on the charge / discharge state, and a is the value in the completely discharged state.)

Li _a Ni _(1-b) M12 _b O _(2-c) F _d ... (22)
(M12 is cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper. (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W). A to d are 0.8. ≤a≤1.2, 0.005≤b≤0.5, -0.1≤c≤0.2 and 0≤d≤0.1 are satisfied. However, the composition of lithium depends on the charge / discharge state. Unlike, a is the value in the completely discharged state.)

Li _a Co _(1-b) M13 _b O _(2-c) F _d ... (23)
(M13 is nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper. (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W). A to d are 0.8. ≦ a ≦ 1.2, 0 ≦ b <0.5, −0.1 ≦ c ≦ 0.2 and 0 ≦ d ≦ 0.1 are satisfied. However, the composition of lithium differs depending on the charge / discharge state. a is the value in the completely discharged state.)

The lithium-containing composite oxide having a layered rock salt type crystal structure may be, for example, a compound represented by the following formula (24). This compound is a lithium nickel-containing composite oxide containing nickel as a constituent element and having a relatively large nickel content.

Li _x Co _y Ni _z M _{1-yz Oba} X _e ... (24)
(M is boron (B), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), gallium (Ga), indium (Y), zirconium (Zr), molybdenum. (Mo), strontium (Sr), cesium (Cs), gallium (Ba), indium (In) and antimony (Sb). X is a halogen element. X, y, z. , A and b are 0.8 <x ≦ 1.2, 0 ≦ y ≦ 1.0, 0.5 ≦ z ≦ 1.0, 0 ≦ a ≦ 1.0, 1.8 ≦ b ≦ 2. 2 and y <z are satisfied.)

Specific examples of the lithium-containing composite oxide having a layered rock salt type crystal structure are LiNiO ₂ , LiCoO ₂ , LiCo _0.98 Al _0.01 Mg _0.01 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.8 Co _0.15 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , Li _1.2 Mn _0.52 Co _0.175 Ni _0.1 O ₂ and Li _1.15 (Mn _0.65 Ni _0.22 Co _0.13 ) O ₂ .

When the lithium-containing composite oxide having a layered rock salt type crystal structure contains nickel, cobalt, manganese and aluminum as constituent elements, the atomic ratio of nickel is preferably 50 atomic% or more. This is because a high energy density can be obtained.

The lithium-containing composite oxide having a spinel-type crystal structure is, for example, a compound represented by the following formula (25).

Li _a Mn _(2-b) M14 _b O _c F _d ... (25)
(M14 is cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper. (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W). A to d are 0.9. ≦ a ≦ 1.1, 0 ≦ b ≦ 0.6, 3.7 ≦ c ≦ 4.1 and 0 ≦ d ≦ 0.1 are satisfied. However, the composition of lithium differs depending on the charge / discharge state, and a Is the value in the fully discharged state.)

Specific examples of the lithium-containing composite oxide having a spinel-type crystal structure are LiMn ₂ O ₄ .

The lithium-containing phosphoric acid compound having an olivine-type crystal structure is, for example, a compound represented by the following formula (26).

Li _a M15PO ₄ ... (26)
(M15 is cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), niobium. (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W) and zirconium (Zr) are at least one of a. 0.9 ≦ a ≦ 1.1 is satisfied. However, the composition of lithium differs depending on the charge / discharge state, and a is the value in the completely discharged state.)

Specific examples of the lithium-containing phosphoric acid compound having an olivine-type crystal structure include LiFePO ₄ , LiMnPO ₄ , LiFe _0.5 Mn _0.5 PO _4, and LiFe _0.3 Mn _0.7 PO ₄ .

The lithium-containing composite oxide may be a compound represented by the following formula (27).

(Li ₂ MnO ₃ ) _x (LiMnO ₂ ) _1-x ... (27)
(X satisfies 0 ≦ x ≦ 1. However, the composition of lithium differs depending on the charge / discharge state, and x is the value in the completely discharged state.)

In addition, the positive electrode material may be any one or more of, for example, oxides, disulfides, chalcogenides and conductive polymers. Oxides include, for example, titanium oxide, vanadium oxide and manganese dioxide. Disulfides include, for example, titanium disulfide and molybdenum sulfide. The chalcogenide is, for example, niobium selenate. Conductive polymers include, for example, sulfur, polyaniline and polythiophene. However, the positive electrode material may be a material other than the above.

The positive electrode binder contains, for example, any one or more of synthetic rubber and polymer compounds. The synthetic rubber is, for example, styrene-butadiene rubber, fluorine-based rubber, ethylene propylene diene and the like. Polymer compounds include, for example, polyvinylidene fluoride and polyimide.

The positive electrode conductive agent contains, for example, any one or more of carbon materials and the like. The carbon material is, for example, graphite, carbon black, acetylene black, ketjen black and the like. However, the positive electrode conductive agent may be a metal material, a conductive polymer, or the like as long as it is a conductive material.

[Negative electrode]
The negative electrode 22 includes, for example, as shown in FIG. 4, a negative electrode current collector 34A and a negative electrode active material layer 34B provided on both sides of the negative electrode current collector 34A. However, the negative electrode active material layer 34B may be provided on only one side of the negative electrode current collector 34A.

The negative electrode current collector 34A contains, for example, any one or more of the conductive materials. The type of the conductive material is not particularly limited, and is, for example, a metal material such as copper, aluminum, nickel, and stainless steel. The negative electrode current collector 34A may be a single layer or a multilayer.

The surface of the negative electrode current collector 34A is preferably roughened. This is because the so-called anchor effect improves the adhesion of the negative electrode active material layer 34B to the negative electrode current collector 34A. In this case, the surface of the negative electrode current collector 34A may be roughened at least in the region facing the negative electrode active material layer 34B. The roughening method is, for example, a method of forming fine particles by using an electrolytic treatment. In the electrolytic treatment, fine particles are formed on the surface of the negative electrode current collector 34A by the electrolytic method in the electrolytic cell, so that the surface of the negative electrode current collector 34A is provided with irregularities. The copper foil produced by the electrolytic method is generally called an electrolytic copper foil.

The negative electrode active material layer 34B contains, as the negative electrode active material, any one or more of the negative electrode materials capable of occluding and releasing lithium. However, the negative electrode active material layer 34B may further contain any one or more of other materials such as a negative electrode binder and a negative electrode conductive agent.

In order to prevent unintentional precipitation of lithium metal on the negative electrode 34 during charging, the chargeable capacity of the negative electrode material is preferably larger than the discharge capacity of the positive electrode 33. That is, it is preferable that the electrochemical equivalent of the negative electrode material capable of occluding and releasing lithium is larger than the electrolytic equivalent of the positive electrode 33.

The negative electrode material is, for example, any one or more of carbon materials. This is because a high energy density can be stably obtained because the change in the crystal structure during the occlusion and release of lithium is very small. Further, since the carbon material also functions as a negative electrode conductive agent, the conductivity of the negative electrode active material layer 34B is improved.

The carbon material is, for example, easy graphitizing carbon, non-graphitizable carbon, graphite and the like. However, the interplanar spacing of the (002) plane in graphitizable carbon is preferably 0.37 nm or more, and the interplanar spacing of the (002) plane in graphite is preferably 0.34 nm or less. More specifically, the carbon material is, for example, pyrolysis carbons, cokes, glassy carbon fibers, calcined organic polymer compound, activated carbon, carbon blacks and the like. These cokes include pitch coke, needle coke, petroleum coke and the like. The organic polymer compound calcined product is obtained by calcining (carbonizing) a polymer compound such as a phenol resin and a furan resin at an appropriate temperature. In addition, the carbon material may be low crystalline carbon heat-treated at a temperature of about 1000 ° C. or lower, or amorphous carbon. The shape of the carbon material may be any of fibrous, spherical, granular and scaly.

The negative electrode material is, for example, a material (metal-based material) containing any one or more of a metal element and a metalloid element as a constituent element. This is because a high energy density can be obtained.

The metal-based material may be any of simple substances, alloys and compounds, two or more of them, or a material having at least one or two or more phases of them. .. However, in addition to the material composed of two or more kinds of metal elements, the alloy also includes a material containing one or more kinds of metal elements and one or more kinds of metalloid elements. The alloy may also contain non-metallic elements. The structure of this metallic material is, for example, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, and a coexistence of two or more of them.

The above-mentioned metal element and metalloid element are, for example, any one or more of the metal element and the metalloid element capable of forming an alloy with lithium. Specifically, for example, magnesium (Mg), boron (B), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb). ), Bismus (Bi), cadmium (Cd), silver (Ag), zinc, hafnium (Hf), zirconium, indium (Y), palladium (Pd) and platinum (Pt).

Of these, one or both of silicon and tin are preferred. This is because the ability to occlude and release lithium is excellent, so that an extremely high energy density can be obtained.

The material containing one or both of silicon and tin as constituent elements may be either a simple substance of silicon, an alloy and a compound, or any of a simple substance of tin, an alloy and a compound, and among them. It may be two or more kinds of materials, or a material having at least one kind or two or more kinds of phases among them. The simple substance described here means a simple substance in a general sense (may contain a trace amount of impurities), and does not necessarily mean 100% purity.

The silicon alloy may be, for example, one of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, chromium and the like as constituent elements other than silicon. Includes two or more types. The silicon compound contains, for example, any one or more of carbon and oxygen as constituent elements other than silicon. The silicon compound may contain, for example, any one or more of the series of elements described for the silicon alloy as a constituent element other than silicon.

Specific examples of silicon alloys and silicon compounds include SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, respectively. FeSi ₂ , MnSi ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0 <v ≦ 2), LiSiO, and the like. The _v in SiO _v may be 0.2 <v <1.4.

The tin alloy may be, for example, any one of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium as constituent elements other than tin. Includes two or more types. The tin compound contains, for example, any one or more of carbon, oxygen, and the like as constituent elements other than tin. The tin compound may contain, for example, any one or more of the series of elements described for tin alloys as constituent elements other than tin.

Specific examples of tin alloys and tin compounds are SnO _w (0 <w ≦ 2), SnSiO ₃ , LiSnO and Mg ₂ Sn.

In particular, the material containing tin as a constituent element is preferably, for example, a material containing a second constituent element and a third constituent element together with tin as the first constituent element (Sn-containing material). The second constituent elements are, for example, cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cesium (Ce), hafnium (Hf), It contains any one or more of tantalum, tungsten, bismuth, silicon and the like. The third constituent element contains, for example, any one or more of boron, carbon, aluminum, phosphorus and the like. This is because the Sn-containing material contains the second and third constituent elements, so that a high battery capacity and excellent cycle characteristics can be obtained.

Above all, the Sn-containing material is preferably a material containing tin, cobalt and carbon as constituent elements (SnCoC-containing material). In this SnCoC-containing material, for example, the carbon content is 9.9% by mass to 29.7% by mass, and the ratio of tin and cobalt contents (Co / (Sn + Co)) is 20% by mass to 70% by mass. .. This is because a high energy density can be obtained.

The SnCoC-containing material has a phase containing tin, cobalt and carbon, and the phase is preferably low crystallinity or amorphous. Since this phase is a reaction phase capable of reacting with lithium, excellent properties can be obtained based on the presence of the reaction phase. The full width at half maximum (diffraction angle 2θ) of the diffraction peak obtained by X-ray diffraction of this reaction phase shall be 1 ° or more when CuKα ray is used as the specific X-ray and the insertion speed is 1 ° / min. Is preferable. This is because lithium is occluded and released more smoothly and the reactivity with the electrolytic solution is reduced. In addition to the low crystalline or amorphous phase, the SnCoC-containing material may contain a phase containing a simple substance or a part of each constituent element.

Whether or not the diffraction peak obtained by X-ray diffraction corresponds to the reaction phase capable of reacting with lithium can be easily determined by comparing the X-ray diffraction charts before and after the electrochemical reaction with lithium. For example, if the position of the diffraction peak changes before and after the electrochemical reaction with lithium, it corresponds to the reaction phase capable of reacting with lithium. In this case, for example, the diffraction peak of the low crystalline or amorphous reaction phase is observed between 2θ = 20 ° and 50 °. Such a reaction phase contains, for example, each of the above-mentioned constituent elements, and is considered to be low-crystallized or amorphized mainly due to the presence of carbon.

In the SnCoC-containing material, it is preferable that at least a part of carbon which is a constituent element is bonded to a metal element or a metalloid element which is another constituent element. This is because aggregation or crystallization of tin and the like is suppressed. The bonding state of the elements can be confirmed by using, for example, X-ray photoelectron spectroscopy (XPS). In a commercially available device, for example, Al-Kα ray or Mg-Kα ray is used as the soft X-ray. When at least a part of carbon is bonded to a metal element, a metalloid element, or the like, the peak of the synthetic wave in the 1s orbital (C1s) of carbon appears in a region lower than 284.5 eV. It is assumed that the peak of the 4f orbital (Au4f) of the gold atom is energy calibrated so as to be obtained at 84.0 eV. At this time, since surface-contaminated carbon is usually present on the surface of the substance, the peak of C1s of the surface-contaminated carbon is set to 284.8 eV, and the peak is used as the energy reference. In the XPS measurement, the waveform of the C1s peak is obtained including the peak of surface contaminated carbon and the peak of carbon in the SnCoC-containing material. Therefore, for example, the two peaks are separated by analysis using commercially available software. In the waveform analysis, the position of the main peak existing on the lowest binding energy side is set as the energy reference (284.8 eV).

This SnCoC-containing material is not limited to a material (SnCoC) whose constituent elements are only tin, cobalt and carbon. In addition to tin, cobalt and carbon, the SnCoC-containing material may further include any one of silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium and bismuth. The type or two or more types may be contained as a constituent element.

In addition to the SnCoC-containing material, a material containing tin, cobalt, iron, and carbon as constituent elements (SnCoFeC-containing material) is also preferable. The composition of this SnCoFeC-containing material is arbitrary. For example, when the iron content is set to be low, the carbon content is 9.9% by mass to 29.7% by mass, and the iron content is 0.3% by mass to 5.9% by mass. , The ratio of the contents of iron and cobalt (Co / (Sn + Co)) is 30% by mass to 70% by mass. When the iron content is set to be large, the carbon content is 11.9% by mass to 29.7% by mass, and the ratio of the contents of tin, cobalt and iron ((Co + Fe) / (Sn + Co + Fe)). Is 26.4% by mass to 48.5% by mass, and the content ratio of cobalt and iron (Co / (Co + Fe)) is 9.9% by mass to 79.5% by mass. This is because a high energy density can be obtained in such a composition range. The physical properties of the SnCoFeC-containing material (half-value width, etc.) are the same as those of the SnCoC-containing material described above.

In addition, the negative electrode material may be any one or more of, for example, a metal oxide and a polymer compound. Metal oxides include, for example, iron oxide, ruthenium oxide and molybdenum oxide. Polymer compounds include, for example, polyacetylene, polyaniline and polypyrrole.

Among them, the negative electrode material preferably contains both a carbon material and a metal-based material for the following reasons.

Metallic materials, particularly materials containing one or both of silicon and tin as constituent elements, have an advantage of high theoretical capacity, but have a concern that they tend to expand and contract violently during charging and discharging. On the other hand, the carbon material has a concern that the theoretical capacity is low, but has an advantage that it does not easily expand and contract during charging and discharging. Therefore, by using both the carbon material and the metal-based material, expansion and contraction during charging and discharging can be suppressed while obtaining a high theoretical capacity (in other words, battery capacity).

The negative electrode active material layer 34B is formed by any one or more of a coating method, a gas phase method, a liquid phase method, a thermal spraying method, a firing method (sintering method), and the like. The coating method is, for example, a method in which a particle (powder) negative electrode active material is mixed with a negative electrode binder or the like, the mixture is dispersed in an organic solvent or the like, and then the negative electrode current collector 34A is coated. The vapor phase method is, for example, a physical deposition method and a chemical deposition method. More specifically, for example, a vacuum vapor deposition method, a sputtering method, an ion plating method, a laser ablation method, a thermochemical vapor deposition method, a chemical vapor deposition (CVD) method, a plasma chemical vapor deposition method, and the like. The liquid phase method is, for example, an electrolytic plating method and an electroless plating method. The thermal spraying method is a method of spraying a molten or semi-molten negative electrode active material onto the negative electrode current collector 34A. The firing method is, for example, a method in which a mixture dispersed in an organic solvent or the like is applied to the negative electrode current collector 34A by using a coating method, and then heat treatment is performed at a temperature higher than the melting point of the negative electrode binder or the like. As this firing method, for example, an atmosphere firing method, a reaction firing method, a hot press firing method, and the like can be used.

In this secondary battery, as described above, in order to prevent unintentional precipitation of lithium on the negative electrode 34 during charging, the electrolytic equivalent of the negative electrode material capable of occluding and releasing lithium is , It is larger than the electrochemical equivalent of the positive electrode. Further, when the open circuit voltage (that is, the battery voltage) at the time of full charge is 4.25 V or more, the same positive electrode active material is used as compared with the case where the open circuit voltage at the time of full charge is 4.20 V. However, since the amount of lithium released per unit mass increases, the amounts of the positive electrode active material and the negative electrode active material are adjusted accordingly. As a result, a high energy density can be obtained.

The open circuit voltage (charging end voltage) at the time of full charging is not particularly limited, but is preferably 4.2 V or more as described above. Above all, the open circuit voltage at the time of full charge is preferably 4.25 V or more, and more preferably 4.35 V or more. This is because even if the open circuit voltage at the time of full charge is remarkably increased, the advantages based on the optimization of the mixing ratio of the electrolyte salt and ethylene carbonate described above can be obtained, so that excellent battery characteristics can be obtained. The discharge end voltage is not particularly limited, but is, for example, 3.0 V or less.

[Separator]
The separator 35 is arranged between the positive electrode 33 and the negative electrode 34, for example, as shown in FIG. As a result, the separator 35 mainly separates the positive electrode 33 and the negative electrode 34, and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes.

The separator 35 is, for example, any one type or two or more types of porous membranes such as synthetic resin and ceramic, and may be a laminated film of two or more types of porous membranes. Synthetic resins include, for example, polytetrafluoroethylene, polypropylene and polyethylene.

In particular, the separator 35 may include, for example, the above-mentioned porous film (base material layer) and a polymer compound layer provided on one side or both sides of the base material layer. This is because the adhesion of the separator 35 to each of the positive electrode 33 and the negative electrode 34 is improved, so that the distortion of the wound electrode body 30 is suppressed. As a result, the decomposition reaction of the electrolytic solution is suppressed, and the leakage of the electrolytic solution impregnated in the base material layer is also suppressed, so that the resistance does not easily increase even if charging and discharging are repeated, and the resistance of the secondary battery is suppressed. Swelling is suppressed.

The polymer compound layer contains any one or more of the polymer compounds such as polyvinylidene fluoride. This is because it has excellent physical strength and is electrochemically stable. However, the polymer compound is not limited to polyvinylidene fluoride. When forming this polymer compound layer, for example, a solution in which the polymer compound is dissolved in an organic solvent or the like is applied to the base material layer, and then the base material layer is dried. Further, when forming the polymer compound layer, for example, the base material layer may be immersed in a solution and then dried. The polymer compound layer may contain any one or more of insulating particles such as inorganic particles. Types of inorganic particles include, for example, aluminum oxide, aluminum nitride, boehmite and talc.

[Electrolyte layer]
The electrolyte layer 36 contains an electrolytic solution and a polymer compound. The electrolyte layer 36 described here is a so-called gel-like electrolyte, and the electrolyte solution is held by the polymer compound in the electrolyte layer 36. This is because high ionic conductivity (for example, 1 mS / cm or more at room temperature) can be obtained and leakage of the electrolytic solution is prevented. The electrolyte layer 36 may further contain any one or more of other materials such as additives.

The electrolyte contains a solvent and an electrolyte salt. However, the electrolytic solution may further contain any one or more of other materials such as additives.

(solvent)
The solvent contains any one or more of non-aqueous solvents such as organic solvents. The electrolytic solution containing a non-aqueous solvent is a so-called non-aqueous electrolytic solution.

Non-aqueous solvents are, for example, cyclic carbonates, chain carbonates, lactones, chain carboxylic acid esters and nitriles (mononitriles). This is because excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained.

Cyclic carbonates include, for example, ethylene carbonate, propylene carbonate and butylene carbonate. Chain carbonates include, for example, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate and methylpropyl carbonate. Lactones include, for example, γ-butyrolactone and γ-valerolactone. Chain carboxylic acid esters include, for example, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate and ethyl trimethyl acetate. Nitriles include, for example, acetonitrile, methoxyacetonitrile and 3-methoxypropionitrile.

Other non-aqueous solvents include, for example, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1 , 4-Dioxane, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide and the like. This is because the same advantage can be obtained.

Among them, the solvent preferably contains any one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and the like. This is because high battery capacity, excellent cycle characteristics, and excellent storage characteristics can be obtained. In this case, a high viscosity (high dielectric constant) solvent such as ethylene carbonate and propylene carbonate (for example, relative permittivity ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate (for example, viscosity ≦ 1 mPa) -The combination with s) is more preferable. This is because the dissociability of the electrolyte salt and the mobility of ions are improved.

In particular, the solvent includes unsaturated cyclic carbonic acid ester, halogenated carbonic acid ester, sulfonic acid ester, acid anhydride, dicyano compound (dinitrile compound), diisocyanate compound, phosphoric acid ester, and chain compound having a carbon-carbon triple bond. Any one or more of the above may be included. This is because the chemical stability of the electrolytic solution is improved.

An unsaturated cyclic carbonate is a cyclic carbonate containing one or more unsaturated bonds (intercarbon double bond or intercarbon triple bond). The unsaturated cyclic carbonate is, for example, vinylene carbonate, vinyl carbonate ethylene, methylene carbonate and the like. The content of the unsaturated cyclic carbonate in the solvent is not particularly limited, but is, for example, 0.01% by weight to 10% by weight.

The halogenated carbonic acid ester is a cyclic or chain-like carbonic acid ester containing one or more halogens as constituent elements. When the halogenated carbonic acid ester contains two or more halogens as constituent elements, the type of the two or more halogens may be only one type or two or more types. Cyclic halogenated carbonates include, for example, 4-fluoro-1,3-dioxolan-2-one and 4,5-difluoro-1,3-dioxolan-2-one. Chained halogenated carbonates include, for example, fluoromethylmethyl carbonate, bis (fluoromethyl) carbonate and difluoromethylmethyl carbonate. The content of the halogenated carbonic acid ester in the solvent is not particularly limited, but is, for example, 0.01% by weight to 50% by weight.

Sulfonic acid esters include, for example, monosulfonic acid esters and disulfonic acid esters. The content of the sulfonic acid ester in the solvent is not particularly limited, but is, for example, 0.01% by weight to 10% by weight.

The monosulfonic acid ester may be a cyclic monosulfonic acid ester or a chain monosulfonic acid ester. Cyclic monosulfonic acid esters are, for example, sultones such as 1,3-propane sultone and 1,3-propene sultone. The chain monosulfonic acid ester is, for example, a compound in which the cyclic monosulfonic acid ester is cleaved in the middle. The disulfonic acid ester may be a cyclic disulfonic acid ester or a chain disulfonic acid ester.

Acid anhydrides include, for example, carboxylic acid anhydrides, disulfonic acid anhydrides and carboxylic acid sulfonic acid anhydrides. Carboxylic anhydrides include, for example, succinic anhydride, glutaric anhydride and maleic anhydride. Disulfonic anhydrides include, for example, ethanedisulfonic anhydride and propanedisulfonic anhydride. Carboxylic acid sulfonic acid anhydrides include, for example, sulfobenzoic acid anhydride, sulfopropionic anhydride and sulfobutyric anhydride. The content of the acid anhydride in the solvent is not particularly limited, but is, for example, 0.5% by weight to 5% by weight.

Dinitrile compounds, for _{example, NC-C m H 2m -CN} (m is 1 or more is an integer.) Is a compound represented by the. The dinitrile compounds include, for example, succinonitrile (NC-C ₂ H _4- CN), glutaronitrile (NC-C ₃ H _6- CN), adiponitrile (NC-C ₄ H _8- CN) and phthalonitrile (NC-C 4H _8- CN). NC-C ₆ H _4- CN) and the like. The content of the dinitrile compound in the solvent is not particularly limited, but is, for example, 0.5% by weight to 5% by weight.

The diisocyanate compound is, for example, a compound represented by OCN-C _n H _2n- NCO (n is an integer of 1 or more). The diisocyanate compounds such as hexamethylene diisocyanate _{(OCN-C 6 H 12 -NCO} ) and the like. The content of the diisocyanate compound in the solvent is not particularly limited, but is, for example, 0.5% by weight to 5% by weight.

Phosphate esters include, for example, trimethyl phosphate and triethyl phosphate. The content of the phosphoric acid ester in the solvent is not particularly limited, but is, for example, 0.5% by weight to 5% by weight.

A chain compound having an intercarbon triple bond is a chain compound having one or more carbon-carbon triple bonds (-C≡C-). Chain compounds having this carbon-carbon triple bond include, for example, propargyl methyl carbonate (CH≡C-CH ₂ -OC (= O) -O-CH ₃ ) and propargyl methylsulfonate (CH≡C-CH _2). -O-S (= O) _2- CH ₃ ) and so on. The content of the chain compound having a carbon-carbon triple bond in the solvent is not particularly limited, but is, for example, 0.5% by weight to 5% by weight.

(Electrolyte salt)
The electrolyte salt contains, for example, any one or more of salts such as lithium salts. However, the electrolyte salt may contain, for example, a salt other than the lithium salt. The salt other than lithium is, for example, a salt of a light metal other than lithium.

Lithium salts include, for example, lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiAsF ₆ ), and tetraphenyl. Lithium borate (LiB (C ₆ H ₅ ) ₄ ), lithium methanesulfonate (LiCH ₃ SO ₃ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium tetrachloroaluminate (LiAlCl ₄ ), hexafluorofluoride Dilithium silicate (Li ₂ SiF ₆ ), lithium chloride (LiCl), lithium bromide (LiBr) and the like. This is because excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained.

Among them, any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate and lithium hexafluoride is preferable, and lithium hexafluorophosphate is more preferable. .. This is because a higher effect can be obtained because the internal resistance is reduced.

The content of the electrolyte salt is not particularly limited, but is preferably 0.3 mol / kg to 3.0 mol / kg with respect to the solvent. This is because high ionic conductivity can be obtained.

However, in the electrolyte layer 36 which is a gel-like electrolyte, the solvent contained in the electrolytic solution is a broad concept including not only a liquid material but also a material having ionic conductivity capable of dissociating an electrolyte salt. .. Therefore, when a polymer compound having ionic conductivity is used, the polymer compound is also included in the non-aqueous solvent.

Polymer compounds include, for example, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl fluoride, polyvinyl acetate, polyvinyl alcohol, and polymethacrylic. It contains any one or more of methyl acid, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene and polycarbonate. In addition, the polymer compound may be a copolymer. This copolymer is, for example, a copolymer of vinylidene fluoride and hexafluoropyrene. Among them, polyvinylidene fluoride is preferable as the homopolymer, and vinylidene fluoride and hexafluoropyrene are preferable as the copolymer. This is because it is electrochemically stable.

The electrolytic solution may be used as it is instead of the electrolyte layer 36. In this case, the electrolytic solution is impregnated into the wound electrode body 30.

[motion]
This secondary battery operates as follows, for example.

At the time of charging, lithium ions are released from the positive electrode 33, and the lithium ions are occluded in the negative electrode 34 via the electrolyte layer 36. On the other hand, at the time of discharge, lithium ions are released from the negative electrode 34, and the lithium ions are occluded in the positive electrode 33 via the electrolyte layer 36.

[Production method]
The secondary battery provided with the gel-like electrolyte layer 36 is manufactured by, for example, the following three types of procedures.

(First step)
When producing the positive electrode 33, first, the positive electrode active material is mixed with a positive electrode binder, a positive electrode conductive agent, and the like, if necessary, to obtain a positive electrode mixture. Subsequently, the positive electrode mixture is dispersed in an organic solvent or the like to obtain a paste-like positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry is applied to both surfaces of the positive electrode current collector 33A, and then the positive electrode mixture slurry is dried to form the positive electrode active material layer 33B. Finally, the positive electrode active material layer 33B is compression-molded using a roll press or the like while heating the positive electrode active material layer 33B as needed. In this case, compression molding may be repeated a plurality of times.

When the negative electrode 34 is manufactured, the negative electrode active material layers 34B are formed on both sides of the negative electrode current collector 34A by the same procedure as the positive electrode 33 described above. Specifically, first, the negative electrode active material is mixed with a negative positive electrode binder, a negative electrode conductive agent, or the like to obtain a negative electrode mixture, and then the negative electrode mixture is dispersed in an organic solvent or the like. A paste-like negative electrode mixture slurry is used. Subsequently, the negative electrode mixture slurry is applied to both sides of the negative electrode current collector 34A, and then the negative electrode mixture slurry is dried to form the negative electrode active material layer 34B. Finally, the negative electrode active material layer 34B is compression-molded using a roll press or the like.

When forming the gel-like electrolyte layer 36, first, a precursor solution is prepared by mixing an electrolytic solution, a polymer compound, an organic solvent, or the like. Subsequently, a precursor solution is applied to the positive electrode 33, and then the precursor solution is dried to form a gel-like electrolyte layer 36. Further, a gel-like electrolyte layer 36 is formed by applying a precursor solution to the negative electrode 34 and then drying the precursor solution.

When assembling the secondary battery, first, the positive electrode lead 31 is attached to the positive electrode current collector 33A by a welding method or the like, and the negative electrode lead 32 is attached to the negative electrode current collector 34A by a welding method or the like. Subsequently, the positive electrode 33 and the negative electrode 34 are laminated via the separator 35, and then the positive electrode 33, the negative electrode 34, and the separator 35 are wound to form the wound electrode body 30. Subsequently, the protective tape 37 is attached to the outermost peripheral portion of the wound electrode body 30. Finally, the exterior member 40 provided with the window portion 42 is used to fold the exterior member 40 so as to sandwich the wound electrode body 30, and then the outer edge portions of the exterior member 40 are joined to each other by a heat fusion method or the like. By laminating, the wound electrode body 30 is sealed inside the exterior member 40. In this case, the adhesion film 50 is inserted between the positive electrode lead 31 and the exterior member 40, and the adhesion film 50 is inserted between the negative electrode lead 32 and the exterior member 40.

As a result, a laminated film type secondary battery provided with the gel-like electrolyte layer 36 is completed.

(Second step)
When assembling the secondary battery after manufacturing each of the positive electrode 33 and the negative electrode 34 by the same procedure as the first procedure, first, the positive electrode lead 31 is attached to the positive electrode 33 and the negative electrode lead 32 is attached to the negative electrode 34. ..

Subsequently, the positive electrode 33 and the negative electrode 34 are laminated via the separator 35 and then wound to produce a wound body which is a precursor of the wound electrode body 30, and then the outermost circumference of the wound body. A protective tape 37 is attached to the portion. Subsequently, using the exterior member 40 provided with the window portion 42, the exterior member 40 is folded so as to sandwich the wound electrode body 30, and then one side of the exterior member 40 is used by a heat fusion method or the like. The wound body is housed inside the bag-shaped exterior member 40 by sticking the remaining outer edge portions excluding the outer edge portion to each other.

Subsequently, a composition for an electrolyte is prepared by mixing an electrolytic solution, a monomer which is a raw material of a polymer compound, a polymerization initiator, and if necessary, another material such as a polymerization inhibitor. Subsequently, the composition for an electrolyte is injected into the bag-shaped exterior member 40, and then the exterior member 40 is sealed by a heat fusion method or the like. Finally, the monomer is thermally polymerized to form a polymeric compound. Since the electrolytic solution is held by this polymer compound, a gel-like electrolyte layer 36 is formed. Therefore, the laminated film type secondary battery is completed.

(Third step)
When assembling the secondary battery, first, the wound body is produced by the same procedure as the above-mentioned second procedure except that the separator 35 on which the polymer compound layer is formed is used, and then the window portion. The winding body is housed inside the bag-shaped exterior member 40 provided with the 42.

Subsequently, after injecting an electrolytic solution into the exterior member 40, the exterior member 40 is sealed by a heat fusion method or the like. Subsequently, by heating the exterior member 40 while applying a load, the separator 35 is brought into close contact with the positive electrode 33 via the polymer compound layer, and the separator 35 is brought into close contact with the negative electrode 34 via the polymer compound layer. As a result, the electrolytic solution impregnates each of the polymer compound layers, and each of the polymer compound layers gels, so that the electrolyte layer 36 is formed. Therefore, the laminated film type secondary battery is completed.

In this third procedure, swelling of the secondary battery is suppressed as compared with the first procedure. Further, in the third procedure, as compared with the second procedure, the solvent and the monomer (raw material of the polymer compound) are less likely to remain in the electrolyte layer 36, so that the process of forming the polymer compound is well controlled. .. Therefore, each of the positive electrode 33, the negative electrode 34, and the separator 35 and the electrolyte layer 36 are easily brought into close contact with each other.

[Action and effect]
According to this laminated film type lithium ion secondary battery, the wound electrode body 30 is housed inside the film-shaped exterior member 40, and the window portion containing the window functional material (non-porous molten fluororesin). A 42 (window film 43) is provided on the exterior member 40 (exterior body 41). Therefore, excellent battery characteristics can be obtained for the reasons described below.

When the window portion 42 is not provided in the exterior member 40, if a gas such as carbon dioxide is generated due to a side reaction such as a decomposition reaction of the electrolytic solution inside the secondary battery, there is no escape place for the gas. Therefore, gas is accumulated inside the secondary battery. In this case, the exterior member 40 is deformed so as to project from the internal environment E1 toward the external environment E2 in response to the increase in the internal pressure, so that the secondary battery swells.

On the other hand, when the exterior member 40 is provided with the window portion 42, as described above, even if gas is generated inside the secondary battery, the exhaust function of the window portion 42 is used to generate gas. Is released to the outside, so that the swelling of the secondary battery is suppressed. Moreover, if the exterior member (exterior body 41) is provided with an opening 41K, there is a concern that water may enter the inside of the secondary battery through the opening 41K, but the waterproof function of the window 42 is used. As a result, the intrusion of water is suppressed, so that the deterioration of cycle characteristics and the like caused by the water is also suppressed. Therefore, without using equipment such as machines, appliances and devices such as safety valves, the window portion 42 is used to suppress the swelling of the secondary battery and the deterioration of the cycle characteristics and the like, resulting in excellent battery characteristics. Is obtained.

In particular, if the window functional material (non-porous molten fluororesin) contains any one or more of non-porous PFA, non-porous FEP, non-porous ETFE, etc., the window portion 42 Is more likely to suppress the intrusion of water, and the window portion 42 is more likely to release gas, so that a higher effect can be obtained.

Further, if the exterior main body 41 is provided with the opening 41K and the window 42 is formed by covering the opening 41K with the window film 43 containing the window functional material, the opening 41K (window film 43). ), Since the gas is sufficiently released, a higher effect can be obtained.

In this case, if the window film 43 has an area larger than the area of the opening 41K and the window film 43 is attached to the exterior body 41 via the adhesive 44, the exterior body 41 is attached. The window film 43 is firmly fixed to the window film 43. Therefore, since the waterproof function and the exhaust function of the window portion 42 are stably exhibited, a higher effect can be obtained.

Further, when the thickness of the window film 43 is 10 μm to 500 μm, a sufficient waterproof function and a sufficient exhaust function can be obtained while ensuring the physical durability of the window film 43, so that a higher effect can be obtained. Can be done.

<1-2. Lithium metal rechargeable battery ＞
The secondary battery described here is a laminated film type lithium metal secondary battery in which the capacity of the negative electrode 34 can be obtained by precipitation and dissolution of lithium metal. This secondary battery has the same configuration as the above-mentioned laminated film type lithium ion secondary battery except that the negative electrode active material layer 34B is formed of lithium metal, and by the same procedure. Manufactured.

Since lithium metal is used as the negative electrode active material in this secondary battery, a high energy density can be obtained. The negative electrode active material layer 34B may already be present at the time of assembly, but may not be present at the time of assembly and may be formed of the lithium metal precipitated at the time of charging. Further, the negative electrode current collector 34A may be omitted by using the negative electrode active material layer 34B as the current collector.

This secondary battery operates as follows, for example. At the time of charging, lithium ions are released from the positive electrode 33, and the lithium ions are deposited as lithium metal on the surface of the negative electrode current collector 34A via the electrolyte layer 36. On the other hand, at the time of discharge, the lithium metal becomes lithium ions from the negative electrode active material layer 34B and elutes into the electrolyte layer 36, and the lithium ions are occluded in the positive electrode 21 via the electrolyte layer 36.

According to this laminated film type lithium metal secondary battery, the wound electrode body 30 is housed inside the film-shaped exterior member 40, and the window portion 42 (window film 43) including the window functional material is the exterior member. It is provided in 40 (exterior main body 41). Therefore, excellent battery characteristics can be obtained for the same reason as the above-mentioned lithium ion secondary battery. Other actions and effects with respect to the lithium metal secondary battery are similar to those with respect to the lithium ion secondary battery.

<1-3. Modification example>
The configuration of the secondary battery of the present embodiment can be changed as appropriate.

(Modification example 1)
Specifically, the window film 43 may be adhered to the exterior body 41 by using any one or more of the methods that do not use the adhesive 44, for example. The method without using the adhesive 44 is, for example, a heat bonding method and an ultrasonic welding method. Even in this case, since the window film 43 is fixed to the exterior body 41, the same effect can be obtained.

(Modification 2)
Further, for example, as shown in FIG. 5 corresponding to FIG. 2, a window portion 42 may be provided on the side surface 41PS instead of the upper surface 41PT of the recessed portion 41P. The opening shape and opening area of the opening 41K can be arbitrarily set, and the planar shape and area of the window film 43 can be arbitrarily set. Here, for example, the opening shape of the opening 41K and the planar shape of the window film 43 are each substantially rectangular (rectangular with four corners rounded), and the area of the window film 43 is the opening of the opening 41K. It is larger than the area. Even in this case, the same effect can be obtained by exerting the waterproof function and the exhaust function of the window portion 24.

(Modification 3)
Further, for example, as shown in FIG. 6 corresponding to FIG. 3, the window film 43 is arranged outside the exterior body 41 (external environment E2) instead of the inside of the exterior body 41 (internal environment E1). You may. The window film 43 is adhered to the outer surface of the exterior body 41 via, for example, an adhesive 44. Even in this case, the same effect can be obtained by exerting the waterproof function and the exhaust function of the window portion 24.

However, as described above, if the window film 43 is arranged outside the exterior main body 41, the window film 43 may be peeled off due to the generation of gas (increase in internal pressure), and the window film 43 may be peeled off. 43 may fall out of the secondary battery. Therefore, in order to prevent the window film 43 from peeling off and falling off, it is preferable that the window film 43 is arranged inside the exterior main body 41 (internal environment E1).

(Modification example 4)
Further, for example, as shown in FIG. 7 corresponding to FIG. 3, the protective layer 46 may be provided on the window film 43. The "above the window film 43" means the outside of the window film 43.

The protective layer 46 mainly functions to physically protect the surface of the window film 43. The protective layer 46 contains, for example, any one or more of the breathable materials. The type of material having breathability is not particularly limited, and is, for example, a porous resin, a ceramic, a mesh filter, and the like. The type of the porous resin is not particularly limited, but for example, porous polytetrafluoroethylene (PTFE), nylon, polypropylene (PP), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC). ) And polyethylene. Since the thickness of the protective layer 46 is not particularly limited, it can be arbitrarily set.

If the protective layer 46 can protect the window film 43, the size (area) of the protective layer 46 is not particularly limited. That is, the area of the protective layer 46 may be the same as the exposed area of the window film 43 (the area of the window film 43 exposed to the opening 41K), or may be larger than the exposed area of the window film 43.

Here, the protective layer 46 has, for example, an area larger than the exposed area of the window film 43, and is adhered to the exterior main body 41 via the adhesive 45. The adhesive 45 is preferably provided so as not to block the opening 41K, for example, in order to secure air permeability using the window film 43. FIG. 7 shows, for example, a case where the protective layer 46 is prevented from being adhered to the window film 43 via the adhesive 45. The details regarding the adhesive 45 are the same as those regarding the adhesive 44, for example.

In this case, since the window film 43 is physically protected by the protective layer 46, deformation, breakage, and peeling of the window film 43 due to an external force are suppressed. Moreover, since the breathable material has a property of easily allowing gas to pass through, even if the protective layer 46 is provided on the window film 43, the gas is released to the outside through the protective layer 46. Will be done. Therefore, the physical durability of the window film 43 is improved while the exhaust function of the window portion 42 is ensured, so that a higher effect can be obtained.

Although not specifically shown here, for example, when the window film 43 is arranged outside the exterior main body 41 as shown in FIG. 6, the protective layer 46 is provided on the window film 43. You may. The protective layer 46 is adhered to the exterior body 41 or the like via, for example, an adhesive 45. In this case as well, the same effect can be obtained.

<2. Secondary battery (second embodiment)>
Next, the secondary battery of the second embodiment will be described. In the following, the components of the secondary battery of the first embodiment will be quoted as needed.

<2-1. Lithium-ion secondary battery ＞
The secondary battery described here is a lithium ion secondary battery. This secondary battery has the secondary of the first embodiment, except that the exterior body 41 is not provided with the opening 41K and the exterior member 40 has the window 47 instead of the window 42. It has the same configuration as a battery and is manufactured by the same procedure.

[Constitution]
FIG. 8 shows a perspective configuration (state after bonding) of the secondary battery of the present embodiment, and corresponds to each of FIGS. 1 and 2. However, in FIG. 8, as in FIG. 2, the illustration of the positive electrode lead 31 and the negative electrode lead 32 is omitted.

FIG. 9 shows the cross-sectional configuration of the exterior member 40 along the CC line shown in FIG. FIG. 10 shows the cross-sectional configuration of the exterior member 40 along the DD line shown in FIG.

The window portion 47 mainly performs the same functions (waterproof function and exhaust function) as the window portion 42. As shown in FIG. 8, the window portion 47 is provided in the adhesive region 41Y instead of the non-adhesive region 41X in the exterior main body 41, and includes the window film 48 instead of the window film 43. There is.

Specifically, for example, in a state where the window film 48 is sandwiched between the exterior portions 41A and 41B, the exterior portions 41A and 41B are adhered to each other to form the window portion 47. That is, the window portion 47 includes, for example, a window functional material (non-porous molten fluororesin) and a window film 48 interposed between the exterior portions 41A and 41B. In FIG. 8, the window portion 47 (window film 48) is shaded in order to make it easy to identify.

As shown in FIGS. 9 and 10, the window portion 47 is exposed to the internal environment E1 and the external environment E2, respectively. The reason why the window portion 47 is provided on the exterior member 40 is the same as when the window portion 42 is provided on the exterior member 40. That is, by utilizing the waterproof function and the exhaust function of the window portion 47, deterioration of cycle characteristics and the like is suppressed and swelling of the secondary battery is suppressed without using equipment such as machines such as safety valves, appliances and devices. Will be done.

The number, position, and configuration of the window portions 47 are not particularly limited as long as the above-mentioned waterproof function and exhaust function can be exhibited.

The number of windows 47 may be only one or two or more. Here, the number of windows 47 is, for example, one.

Further, the position of the window portion 47 may be arbitrary as long as it is at any position of the adhesive region 41Y. Here, the window portion 47 is provided, for example, in a part of the adhesive region 41Y on the side where each of the positive electrode lead 31 and the negative electrode lead 32 is introduced from the inside to the outside of the exterior member 40.

The window film 48, like the window film 43, contains any one or more of the window functional materials. The planar shape of the window film 48 is not particularly limited, and may be, for example, a circular shape, an elliptical shape, a rectangular shape, or any other shape. Here, the planar shape of the window film 48 is, for example, a rectangle.

The window film 48 is, for example, adhered to the exterior body 41 (exterior portion 41A) via an adhesive 49, and is also adhered to the exterior body 41 (exterior portion 41B) via an adhesive 49. .. The details regarding the adhesive 49 are the same as those regarding the adhesive 44, for example.

In the region where the window film 48 does not exist, the adhesive layer of the exterior portion 41A and the adhesive layer of the outer layer portion 41B are adhered to each other as described above. As a result, the exterior member 40 is sealed.

The thickness of the window film 48 is not particularly limited, but is, for example, 10 μm to 500 μm, preferably 10 μm to 200 μm. This is because, as in the case where the thickness of the window film 43 is specified, a sufficient waterproof function and a sufficient exhaust function can be obtained while ensuring the physical durability of the window film 48 and the like.

When the adhesiveness between the adhesive 49 and the window film 48 is not sufficient, for example, in order to improve the adhesiveness as in the case where the adhesiveness between the adhesive 44 and the window film 43 is not sufficient. In addition, any one or more of the pretreatments may be applied to the surface of the window film 48. Details regarding the pretreatment are as described above, for example.

Of course, when the adhesiveness between the adhesive 49 and the exterior body 41 is not sufficient, for example, in order to improve the adhesiveness as in the case where the adhesiveness between the adhesive 44 and the exterior body 41 is not sufficient. In addition, any one or more of the pretreatments may be applied to the surface of the exterior body 41.

[Production method]
This secondary battery is different from the case where the exterior member 40 provided with the window portion 48 is used, for example, by attaching the window film 48 to the exterior main body 41 (exterior portions 41A, 41B) using the adhesive 49. , Manufactured by the same procedure as the secondary battery of the first embodiment.

[Action and effect]
According to this laminated film type lithium ion secondary battery, the wound electrode body 30 is housed inside the film-shaped exterior member 40, and the window portion 47 (window film 48) including the window functional material is the exterior member. It is provided in 40. In this case, for the same reason as the secondary battery of the first embodiment, the waterproof function of the window film 48 is utilized to suppress deterioration of cycle characteristics and the like due to water, and the window film 48 The swelling of the secondary battery is suppressed by using the exhaust function. Therefore, excellent battery characteristics can be obtained.

In particular, if the window portion 48 is formed by adhering the exterior portions 41A and 41B to each other via the window film 48 containing the window functional material, the window portion 48 does not have to be provided with an opening or the like in the exterior main body 41. Is formed, so that a higher effect can be obtained.

Further, when the thickness of the window film 48 is 10 μm to 500 μm, a sufficient waterproof function and a sufficient exhaust function can be obtained while ensuring the physical durability of the window film 48, so that a higher effect can be obtained. Can be done.

Other actions and effects regarding the secondary battery of the present embodiment are the same as those of the secondary battery of the first embodiment.

<2-2. Lithium metal rechargeable battery ＞
The secondary battery described here is a laminated film type lithium metal secondary battery. This secondary battery has the same configuration as the above-mentioned laminated film type lithium ion secondary battery except that lithium metal is used as the negative electrode active material, and is manufactured by the same procedure. To.

According to this laminated film type lithium metal secondary battery, the wound electrode body 30 is housed inside the film-shaped exterior member 40, and the window portion 47 (window film 48) including the window functional material is the exterior member. It is provided in 40. Therefore, excellent battery characteristics can be obtained for the same reason as the above-mentioned lithium ion secondary battery. Other actions and effects with respect to the lithium metal secondary battery are similar to those with respect to the lithium ion secondary battery.

<2-3. Modification example>
The configuration of the secondary battery of the present embodiment can be changed as appropriate. Specifically, the window film 48 may be attached to the exterior main body 41 by using any one or more of the methods that do not use the adhesive 49, as in the window film 43, for example. Good. Details of the method without using the adhesive 49 are as described above, for example. Even in this case, since the window film 48 is fixed to the exterior body 41, the same effect can be obtained.

<3. Applications for secondary batteries>
Next, an application example of the above-mentioned secondary battery will be described.

Secondary batteries are used in machines, devices, appliances, devices and systems (aggregates of multiple devices, etc.) that can use the secondary batteries as a power source for driving or a power storage source for storing power. If there is, there is no particular limitation. The secondary battery used as a power source may be a main power source or an auxiliary power source. The main power source is a power source that is preferentially used regardless of the presence or absence of another power source. The auxiliary power supply may be, for example, a power supply used in place of the main power supply, or a power supply that can be switched from the main power supply as needed. When a secondary battery is used as an auxiliary power source, the type of main power source is not limited to the secondary battery.

The uses of the secondary battery are as follows, for example. Electronic devices (including portable electronic devices) such as video cameras, digital still cameras, mobile phones, laptop computers, cordless phones, headphone stereos, portable radios, portable TVs and portable information terminals. It is a portable living appliance such as an electric shaver. A storage device such as a backup power supply and a memory card. Electric tools such as electric drills and electric saws. It is a battery pack that is installed in notebook computers as a removable power source. Medical electronic devices such as pacemakers and hearing aids. It is an electric vehicle such as an electric vehicle (including a hybrid vehicle). It is a power storage system such as a household battery system that stores power in case of an emergency. Of course, the use of the secondary battery may be other than the above.

Above all, it is effective that the secondary battery is applied to a battery pack, an electric vehicle, a power storage system, an electric tool, an electronic device, and the like. This is because excellent battery characteristics are required for these applications, and the performance can be effectively improved by using the secondary battery of the present technology. The battery pack is a power source using a secondary battery. As will be described later, this battery pack may use a single battery or an assembled battery. The electric vehicle is a vehicle that operates (runs) using a secondary battery as a driving power source, and may be a vehicle (hybrid vehicle or the like) that also has a drive source other than the secondary battery as described above. A power storage system is a system that uses a secondary battery as a power storage source. For example, in a household electric power storage system, since electric power is stored in a secondary battery which is an electric power storage source, it is possible to use the electric power for household electric products and the like. A power tool is a tool in which a movable part (for example, a drill or the like) can be moved by using a secondary battery as a power source for driving. An electronic device is a device that exerts various functions by using a secondary battery as a power source (power supply source) for driving.

Here, some application examples of the secondary battery will be specifically described. Since the configuration of the application example described below is only an example, the configuration of the application example can be changed as appropriate.

<3-1. Battery pack (cell) ＞
FIG. 11 shows a perspective configuration of a battery pack using a cell. FIG. 12 shows the block configuration of the battery pack shown in FIG. Note that FIG. 11 shows a state in which the battery pack is disassembled.

The battery pack described here is a simple battery pack (so-called soft pack) using one secondary battery of the present technology, and is mounted on, for example, an electronic device represented by a smartphone. As shown in FIG. 11, the battery pack includes, for example, a power supply 111 which is a laminated film type secondary battery and a circuit board 116 connected to the power supply 111. A positive electrode lead 112 and a negative electrode lead 113 are attached to the power supply 111.

A pair of adhesive tapes 118 and 119 are attached to both side surfaces of the power supply 111. A protection circuit (PCM: Protection, Circuit, Module) is formed on the circuit board 116. The circuit board 116 is connected to the positive electrode 112 via the tab 114 and is connected to the negative electrode lead 113 via the tab 115. Further, the circuit board 116 is connected to a lead wire 117 with a connector for external connection. In the state where the circuit board 116 is connected to the power supply 111, the circuit board 116 is protected by the label 120 and the insulating sheet 121. By attaching the label 120, the circuit board 116, the insulating sheet 121, and the like are fixed.

Further, the battery pack includes, for example, a power supply 111 and a circuit board 116 as shown in FIG. The circuit board 116 includes, for example, a control unit 121, a switch unit 122, a PTC element 123, and a temperature detection unit 124. Since the power supply 111 can be connected to the outside via the positive electrode terminal 125 and the negative electrode terminal 127, the power supply 111 is charged and discharged via the positive electrode terminal 125 and the negative electrode terminal 127. The temperature detection unit 124 detects the temperature using the temperature detection terminal (so-called T terminal) 126.

The control unit 121 controls the operation of the entire battery pack (including the usage state of the power supply 111). The control unit 121 includes, for example, a central processing unit (CPU) and a memory.

For example, when the battery voltage reaches the overcharge detection voltage, the control unit 121 disconnects the switch unit 122 so that the charging current does not flow in the current path of the power supply 111. Further, for example, when a large current flows during charging, the control unit 121 cuts off the charging current by disconnecting the switch unit 122.

On the other hand, the control unit 121 cuts off the switch unit 122 when, for example, the battery voltage reaches the over-discharge detection voltage, so that the discharge current does not flow in the current path of the power supply 111. Further, for example, when a large current flows during discharging, the control unit 121 cuts off the discharging current by disconnecting the switch unit 122.

The overcharge detection voltage is, for example, 4.2 V ± 0.05 V, and the over discharge detection voltage is, for example, 2.4 V ± 0.1 V.

The switch unit 122 switches the usage state of the power supply 111, that is, whether or not the power supply 111 is connected to an external device, in response to an instruction from the control unit 121. The switch unit 122 includes, for example, a charge control switch and a discharge control switch. Each of the charge control switch and the discharge control switch is a semiconductor switch such as a field effect transistor (MOSFET) using a metal oxide semiconductor, for example. The charge / discharge current is detected based on, for example, the ON resistance of the switch unit 122.

The temperature detection unit 124 measures the temperature of the power supply 111 and outputs the measurement result of the temperature to the control unit 121. The temperature detection unit 124 includes, for example, a temperature detection element such as a thermistor. The temperature measurement result measured by the temperature detection unit 124 is used when the control unit 121 performs charge / discharge control during abnormal heat generation, or when the control unit 121 performs correction processing when calculating the remaining capacity. ..

The circuit board 116 does not have to include the PTC element 123. In this case, a PTC element may be separately attached to the circuit board 116.

<3-2. Battery pack (assembled battery)>
FIG. 13 shows a block configuration of a battery pack using an assembled battery.

This battery pack contains, for example, a control unit 61, a power supply 62, a switch unit 63, a current measurement unit 64, a temperature detection unit 65, a voltage detection unit 66, and a switch control unit 67 inside the housing 60. A memory 68, a temperature detection element 69, a current detection resistor 70, a positive electrode terminal 71, and a negative electrode terminal 72 are provided. The housing 60 contains, for example, a plastic material.

The control unit 61 controls the operation of the entire battery pack (including the usage state of the power supply 62). The control unit 61 includes, for example, a CPU and the like. The power supply 62 is an assembled battery including two or more types of secondary batteries of the present technology, and the connection type of the two or more types of secondary batteries may be in series, in parallel, or in a mixed type of both. .. As an example, the power supply 62 includes six secondary batteries connected so as to be in two parallels and three series.

The switch unit 63 switches the usage state of the power supply 62, that is, whether or not the power supply 62 is connected to an external device, in response to an instruction from the control unit 61. The switch unit 63 includes, for example, a charge control switch, a discharge control switch, a charging diode, a discharging diode, and the like. Each of the charge control switch and the discharge control switch is a semiconductor switch such as a field effect transistor (MOSFET) using a metal oxide semiconductor, for example.

The current measuring unit 64 measures the current using the current detection resistor 70, and outputs the measurement result of the current to the control unit 61. The temperature detection unit 65 measures the temperature using the temperature detection element 69, and outputs the measurement result of the temperature to the control unit 61. The measurement result of this temperature is used, for example, when the control unit 61 performs charge / discharge control at the time of abnormal heat generation, or when the control unit 61 performs a correction process at the time of calculating the remaining capacity. The voltage detection unit 66 measures the voltage of the secondary battery in the power supply 62, and supplies the measurement result of the analog-digitally converted voltage to the control unit 61.

The switch control unit 67 controls the operation of the switch unit 63 according to the signals input from each of the current measurement unit 64 and the voltage detection unit 66.

For example, when the battery voltage reaches the overcharge detection voltage, the switch control unit 67 disconnects the switch unit 63 (charge control switch) so that the charge current does not flow in the current path of the power supply 62. As a result, in the power supply 62, only discharging is possible via the discharging diode. The switch control unit 67 cuts off the charging current when a large current flows during charging, for example.

Further, the switch control unit 67 cuts off the switch unit 63 (discharge control switch), for example, when the battery voltage reaches the over-discharge detection voltage, so that the discharge current does not flow in the current path of the power supply 62. As a result, the power supply 62 can only be charged via the charging diode. The switch control unit 67 shuts off the discharge current when a large current flows during discharge, for example.

The overcharge detection voltage is, for example, 4.2 V ± 0.05 V, and the over discharge detection voltage is, for example, 2.4 V ± 0.1 V.

The memory 68 includes, for example, EEPROM, which is a non-volatile memory. The memory 68 stores, for example, numerical values calculated by the control unit 61, information on the secondary battery measured in the manufacturing process stage (for example, internal resistance in the initial state, etc.). If the full charge capacity of the secondary battery is stored in the memory 68, the control unit 61 can grasp information such as the remaining capacity.

The temperature detection element 69 measures the temperature of the power supply 62 and outputs the measurement result of the temperature to the control unit 61. The temperature detecting element 69 includes, for example, a thermistor.

Each of the positive electrode terminal 71 and the negative electrode terminal 72 is used for an external device operated by using the battery pack (for example, a notebook personal computer), an external device used for charging the battery pack (for example, a charger), and the like. It is a terminal to be connected. The power supply 62 is charged and discharged via the positive electrode terminal 71 and the negative electrode terminal 72.

<3-3. Electric vehicle>
FIG. 14 shows a block configuration of a hybrid vehicle which is an example of an electric vehicle.

This electric vehicle includes, for example, a control unit 74, an engine 75, a power supply 76, a driving motor 77, a differential device 78, a generator 79, and a transmission 80 inside a metal housing 73. It also includes a clutch 81, inverters 82 and 83, and various sensors 84. In addition, the electric vehicle includes, for example, a front wheel drive shaft 85 and front wheels 86 connected to a differential device 78 and a transmission 80, and a rear wheel drive shaft 87 and a rear wheel 88.

The electric vehicle can travel using, for example, either the engine 75 or the motor 77 as a drive source. The engine 75 is a main power source, for example, a gasoline engine. When the engine 75 is used as a power source, for example, the driving force (rotational force) of the engine 75 is transmitted to the front wheels 86 and the rear wheels 88 via the differential device 78, the transmission 80, and the clutch 81, which are the driving units. To. Since the rotational force of the engine 75 is transmitted to the generator 79, the generator 79 uses the rotational force to generate AC power, and the AC power is converted into DC power via the inverter 83. Therefore, the DC power is stored in the power source 76. On the other hand, when the motor 77, which is a conversion unit, is used as a power source, the electric power (DC power) supplied from the power source 76 is converted into AC electric power via the inverter 82, and the AC electric power is used to convert the motor. 77 is driven. The driving force (rotational force) converted from electric power by the motor 77 is transmitted to the front wheels 86 and the rear wheels 88 via, for example, a differential device 78, a transmission 80, and a clutch 81, which are driving units.

When the electric vehicle decelerates through the braking mechanism, the resistance force at the time of deceleration is transmitted to the motor 77 as a rotational force. Therefore, even if the motor 77 generates AC power by using the rotational force. Good. Since this AC power is converted into DC power via the inverter 82, it is preferable that the DC regenerative power is stored in the power source 76.

The control unit 74 controls the operation of the entire electric vehicle. The control unit 74 includes, for example, a CPU and the like. The power source 76 includes one or more types of secondary batteries of the present technology. The power source 76 may store electric power by being connected to an external power source and receiving power supply from the external power source. The various sensors 84 are used, for example, to control the rotation speed of the engine 75 and to control the opening degree (throttle opening degree) of the throttle valve. The various sensors 84 include, for example, any one or more of a speed sensor, an acceleration sensor, an engine speed sensor, and the like.

Although the case where the electric vehicle is a hybrid vehicle is taken as an example, the electric vehicle may be a vehicle (electric vehicle) that operates using only the power source 76 and the motor 77 without using the engine 75.

<3-4. Power storage system>
FIG. 15 shows the block configuration of the power storage system.

This electric power storage system includes, for example, a control unit 90, a power supply 91, a smart meter 92, and a power hub 93 inside a house 89 such as a general house or a commercial building.

Here, the power supply 91 can be connected to, for example, an electric device 94 installed inside the house 89, and can be connected to an electric vehicle 96 parked outside the house 89. Further, the power supply 91 is connected to, for example, the private power generator 95 installed in the house 89 via the power hub 93, and is also connected to the external centralized power system 97 via the smart meter 92 and the power hub 93. It is possible.

The electric device 94 includes, for example, one or more types of home appliances, and the home appliances include, for example, a refrigerator, an air conditioner, a television, and a water heater. The private power generator 95 includes, for example, any one type or two or more types of a solar power generator and a wind power generator. The electric vehicle 96 includes, for example, any one or more of electric vehicles, electric motorcycles, hybrid vehicles, and the like. The centralized power system 97 includes, for example, any one or more of a thermal power plant, a nuclear power plant, a hydroelectric power plant, a wind power plant, and the like.

The control unit 90 controls the operation of the entire power storage system (including the usage state of the power supply 91). The control unit 90 includes, for example, a CPU and the like. The power supply 91 includes one or more types of secondary batteries of the present technology. The smart meter 92 is, for example, a network-compatible power meter installed in a house 89 on the power demand side, and can communicate with the power supply side. Along with this, the smart meter 92 enables highly efficient and stable energy supply by controlling the balance between the supply and demand of electric power in the house 89 while communicating with the outside, for example.

In this power storage system, for example, power is stored in the power supply 91 from the centralized power system 97, which is an external power source, via the smart meter 92 and the power hub 93, and from the private generator 95, which is an independent power source, via the power hub 93. Power is stored in the power supply 91. Since the electric power stored in the power supply 91 is supplied to the electric device 94 and the electric vehicle 96 according to the instruction of the control unit 90, the electric device 94 can be operated and the electric vehicle 96 can be charged. Become. That is, the electric power storage system is a system that enables the storage and supply of electric power in the house 89 by using the power source 91.

The electric power stored in the power source 91 can be used as needed. Therefore, for example, it is possible to store power from the centralized power system 97 in the power supply 91 at midnight when the electricity usage fee is low, and use the power stored in the power supply 91 during the daytime when the electricity usage fee is high. it can.

The power storage system described above may be installed in each household (one household) or in each of a plurality of households (plural households).

<3-5. Power tools ＞
FIG. 16 shows a block configuration of a power tool.

The power tool described here is, for example, an electric drill. This power tool includes, for example, a control unit 99 and a power supply 100 inside the tool body 98. For example, a drill portion 101, which is a movable portion, is attached to the tool body 98 so that it can be operated (rotated).

The tool body 98 contains, for example, a plastic material. The control unit 99 controls the operation of the entire power tool (including the usage state of the power supply 100). The control unit 99 includes, for example, a CPU and the like. The power source 100 includes one or more types of secondary batteries of the present technology. The control unit 99 supplies electric power from the power supply 100 to the drill unit 101 in response to the operation of the operation switch.

Examples of the present technology will be described.

(Experimental Examples 1-1-1-15)
By providing the window portion 42 (opening 41K and window film 43) in the non-adhesive region 41X of the exterior main body 41 by the following procedure, the laminated film type lithium ions shown in FIGS. 1 to 5 and 7 are provided. A secondary battery was manufactured.

When producing the positive electrode 33, first, 97 parts by mass of the positive electrode active material (LiNi _0.5 Co _0.2 Mn _0.3 O ₂ ), ₂ parts by mass of the positive electrode binder (polyvinylidene fluoride), and the positive electrode conductive agent (carbon black) are used. ) 1 part by mass was mixed to obtain a positive electrode mixture. Subsequently, a positive electrode mixture was added to an organic solvent (N-methyl-2-pyrrolidone), and then the organic solvent was stirred to obtain a paste-like positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry is applied to both sides of the positive electrode current collector 33A (12 μm thick strip-shaped aluminum foil) using a coating device, and then the positive electrode mixture slurry is dried to obtain the positive electrode active material layer 33B. Formed. Finally, the positive electrode active material layer 33B was compression-molded using a roll press machine.

When producing the negative electrode 34, first, 95 parts by mass of the negative electrode active material (granular graphite powder, median diameter D50 = 20 μm) and the negative electrode binder (acrylic modified styrene-butadiene rubber copolymer) 1.5. By mixing 2 parts by mass of the negative electrode binder (fine particle polyvinylidene fluoride, median diameter D50 = 0.3 μm) and 1.5 parts by mass of the thickener (carboxymethyl cellulose), a negative electrode mixture can be obtained. did. Subsequently, the negative electrode mixture was added to the pure water, and then the pure water was stirred to obtain a paste-like negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry is applied to both sides of the negative electrode current collector 34A (15 μm thick strip-shaped copper foil) using a coating device, and then the negative electrode mixture slurry is dried to obtain the negative electrode active material layer 34B. Formed. Finally, the negative electrode active material layer 34B was compression-molded using a roll press machine.

When preparing an electrolytic solution, an electrolyte salt (LiPF ₆ ) is added to a solvent (ethylene carbonate, ethylmethyl carbonate and vinylene carbonate), and then the solvent is stirred to dissolve the electrolyte salt in the solvent. It was. In this case, the mixing ratio (mass ratio) of the solvent was set to ethylene carbonate: ethyl methyl carbonate: vinylene carbonate = 30: 69: 1. The content of the electrolyte salt was set to 1 mol / dm ³ (= 1 mol / l) with respect to the solvent.

When assembling the secondary battery, first, the positive electrode lead 31 made of aluminum was welded to the positive electrode current collector 33A, and the negative electrode lead 32 made of copper was welded to the negative electrode current collector 34A.

Subsequently, the polymer compound (polyvinylidene fluoride) is dissolved in an organic solvent (N-methyl-2-pyrrolidone) to obtain a solution in which the polymer compound is dissolved in the organic solvent, and then the base material layer is obtained. The solution was applied to both sides of (12 μm thick microporous polyethylene film). Subsequently, the base material layer was immersed in a water bath to cause phase separation of the solution, and then the base material layer was dried with warm air. As a result, the polymer compound layers were formed on both sides of the base material layer, so that the separator 35 was obtained.

Subsequently, the positive electrode 33 and the negative electrode 34 were laminated via the separator 35 to form a laminated body. Subsequently, after the laminated body was wound in the longitudinal direction, the wound electrode body 30 was manufactured by attaching a protective tape 37 to the outermost peripheral portion of the laminated body.

Subsequently, the film-shaped exterior member 40 was folded so as to sandwich the wound electrode body 30, and then the outer peripheral edges of the three sides of the exterior member 40 were heat-sealed. The exterior member 40 is an aluminum laminate film in which a nylon film having a thickness of 25 μm, an aluminum foil having a thickness of 40 μm, and a polypropylene film having a thickness of 30 μm are laminated in this order from the outside. When the exterior member 40 is heat-sealed, the adhesion film 50 is inserted between the positive electrode lead 31 and the exterior member 40, and the adhesion film 50 is inserted between the negative electrode lead 32 and the exterior member 40.

In this case, the window film 43 containing the window functional material is attached to the exterior body 41 via the adhesive 44 so as to cover the opening 41K provided in the non-adhesive region 41X of the exterior body 41. Therefore, the exterior member 40 provided with the window portion 42 was used. Further, the exterior member 40 provided with the protective layer 46 was used by attaching the protective layer 46 to the window film 43 via the adhesive 46.

For comparison, an exterior member 40 having no window portion 42 was used. Further, for comparison, the exterior member 40 in which the window film 43 contains a material other than the window functional material was used.

The presence / absence of the window portion 42, the configuration of the opening 41K (position and dimensions (cm × cm)), the configuration of the window film 43 (material and thickness (μm)), and the configuration of the protective layer 46 (presence / absence and material) are shown in Table. It is as shown in 1.

The material of the window film 43 is as follows. As the window functional material (non-porous molten fluororesin), non-porous PFA, non-porous FEP and non-porous ETFE were used. Porous PFA, polypropylene (PP) and polyethylene terephthalate (PET) were used as materials other than the window functional material.

Porous polytetrafluoroethylene (PTFE) was used as the material for forming the protective layer 46 (porous resin).

When the window film 43 containing the window functional material is attached to the exterior body 41 via the adhesive 44, the surface of the window film 43 is first pretreated. In this case, the surface of the window film 43 is modified (so-called fluorobonder treatment) by spraying a pretreatment agent (fluororesin surface treatment agent Fluorobonder E manufactured by Technos Co., Ltd.) on the surface of the window film 43. did. Subsequently, the surface of the exterior body 41 was pretreated. In this case, an undercoating agent (PPX primer manufactured by Cemedine Co., Ltd.) was applied to the surface of the exterior body 41. Finally, the pretreated surface of the window film 43 and the pretreated surface of the exterior body 41 were adhered to each other via an adhesive 44 (PPX manufactured by Cemedine Co., Ltd.).

When the window film 43 containing a material other than the window functional material is attached to the exterior body 41 via the adhesive 44, the window film 43 containing the window functional material is attached to the exterior body 41 via the adhesive 44. The same procedure as in the case was used.

Finally, by injecting an electrolytic solution into the exterior member 40, the separator 35 is impregnated with the electrolytic solution, and then the outer peripheral edges of the remaining one side of the exterior member 40 are heat-sealed together in a reduced pressure environment. did. As a result, since the wound electrode body 30 was enclosed inside the exterior member 40, a laminated film type lithium ion secondary battery (battery size = 80 mm × 60 mm × 40 mm, battery capacity = 3000 mAh) was completed.

In order to evaluate the battery characteristics of the secondary battery, the capacity maintenance characteristics, swelling characteristics, physical durability characteristics and adhesive characteristics of the secondary battery were examined, and the results shown in Table 1 were obtained.

When examining the capacity retention characteristics, first, the secondary battery was stored in a high temperature environment (temperature = 60 ° C., humidity = 90%) using a constant temperature bath (storage period = 7 days). Subsequently, after taking out the secondary battery from the constant temperature bath, the discharge capacity (mAh) was measured by charging and discharging the secondary battery. Finally, the capacity retention rate (%) = (discharge capacity / battery capacity (= 3000 mAr)) × 100 was calculated.

At the time of charging, a constant current was charged with a current of 0.2 A until the voltage reached 4.2 V. At the time of discharge, a constant current was discharged with a current of 0.6 A until the voltage reached 2.5 V.

When examining the swelling characteristics, first, the secondary battery is charged in a room temperature environment (temperature = 23 ° C.), and then the thickness of the charged secondary battery (thickness before storage) is measured using a micrometer. ) Was measured. Subsequently, the rechargeable battery is stored in a high temperature environment (temperature = 60 ° C., humidity = 90%) in a constant temperature bath (storage period = 7 days), and then the rechargeable battery is stored using a micrometer. The thickness of the battery (thickness after storage) was measured. Finally, the thickness change rate (%) = [(thickness after storage-thickness before storage) / thickness before storage] × 100 was calculated.

At the time of charging, constant current charging was performed with a current of 1 A until the voltage reached 4.2 V.

When examining the physical durability characteristics, the scratching state on the outermost surface of the window portion 42 was visually confirmed by performing a scratch test in accordance with JIS K5400-5-4. As a result, the case where the outermost surface of the window portion 42 was not scratched was "A", the case where the outermost surface of the window portion 42 was scratched was "B", and the outermost surface of the window portion 42 was scratched. Not only that, the case where the window portion 42 was damaged was evaluated as "C". The outermost surface of the window portion 42 is the surface of the window film 43 when the protective layer 46 is not provided, and the surface of the protective layer 46 when the protective layer 46 is provided.

When examining the adhesive properties, the adhesive strength of the window film 43 was confirmed by performing an adhesive test in accordance with JIS K7127: 1999. As a result, the case where the window film 43 was not peeled off was evaluated as "A", and the case where the window film 43 was peeled off was evaluated as "C".

When the window portion 42 was not provided (Experimental Example 1-12), a high capacity retention rate was obtained, but the thickness change rate increased. This result indicates that the secondary battery swelled in response to an increase in the internal pressure because gas was generated inside the secondary battery due to the decomposition reaction of the electrolytic solution. In the following, the result when the window portion 42 is not provided is used as a comparison standard.

On the other hand, when the window portion 42 is provided, the capacity retention rate and the thickness change rate vary greatly depending on the material of the window film 43.

Specifically, when materials other than the window functional material (porous PFA and PP) were used as the forming material of the window film 43 (Experimental Examples 1-13 and 1-14), the thickness change rate was significantly reduced. However, the capacity retention rate also decreased significantly. Further, when a material (PET) other than the window functional material was used (Experimental Example 1-15), the high capacity retention rate was maintained, but the thickness change rate was almost the same.

However, when window functional materials (non-porous PFA, non-porous FEP and non-porous ETFE) are used as the forming material of the window film 43 (Experimental Examples 1-1 to 1-11), the opening 41K The rate of change in thickness was significantly reduced while the capacity retention rate was almost maintained, regardless of the position, the type of window functional material, the thickness of the window film 43, and the like. As a result, when the window portion 42 (window film 43 containing the window functional material) is used, the gas generated inside the secondary battery is discharged to the outside, so that the secondary battery is less likely to swell and the secondary battery is less likely to swell. This means that the discharge capacity is less likely to decrease because water is less likely to enter the inside of the battery.

Moreover, when a window functional material is used (Experimental Examples 1-1 to 1-11), the same degree of abrasion as when a material other than the window functional material is used (Experimental Examples 1-13 to 1-15) is used. A state was obtained and the same level of adhesive strength was obtained. That is, even if the window functional material was used as the forming material of the window film 43, the scratched state and the adhesive strength did not deteriorate.

In particular, when a window functional material was used (Experimental Examples 1-1 to 1-11), the following tendencies were obtained. First, when the thickness of the window film 43 was 10 μm to 500 μm, the thickness change rate was sufficiently reduced. In this case, when the thickness of the window film 43 is 200 μm or less, the thickness change rate is further reduced. Secondly, when the protective layer 46 was used, the scratched state on the outermost surface of the window portion 42 was remarkably improved.

(Experimental Examples 2-1 to 2-4)
As shown in Table 2, Experimental Examples 1-1 to 1-15 except that the window portion 47 (window film 48) is provided in the adhesive region 41Y instead of the non-adhesive region 41X in the exterior main body 41. The laminated film type lithium ion secondary batteries shown in FIGS. 8 to 10 were produced by the same procedure as in the above procedure, and the battery characteristics of the secondary batteries were evaluated.

When the window film 48 containing the window functional material is attached to the exterior main body 41 (exterior portions 41A, 41B) via the adhesive 49, first, both sides of the window film 48 are pretreated. In this case, both sides of the window film 48 were modified (fluorobonder treatment) by spraying a pretreatment agent (fluororesin surface treatment agent Fluorobonder E manufactured by Technos Co., Ltd.) on both sides of the window film 48. .. Subsequently, the surface of the exterior portion 41A and the surface of the exterior portion 41B were each subjected to pretreatment. In this case, an undercoating agent (PPX primer manufactured by Cemedine Co., Ltd.) was applied to the surface of the exterior portion 41A, and a similar undercoating agent was applied to the surface of the exterior portion 41B. Finally, the pretreated surface of the window film 48 and the pretreated surface of the exterior portion 41A are adhered to each other via an adhesive 49 (PPX manufactured by Cemedine Co., Ltd.), and the window film is adhered to each other via a similar adhesive 49. The pre-treated surface of 48 and the pre-treated surface of the exterior portion 41B were adhered to each other.

Even when the window portion 47 was provided in the adhesive region 41Y (Table 2), the same result as in the case where the window portion 42 was provided in the non-adhesive region 41X (Table 1) was obtained. That is, when the window portion 47 is provided and the window functional material is used as the forming material of the window film 48 (Experimental Examples 2-1 to 2-41), the window portion 47 is not provided (Experimental Example 1). Compared with -12) and the case where a material other than the window functional material is used as the forming material of the window film 48 (Experimental Examples 1-13 to 1-15), a high capacity retention rate and a thickness change rate can be obtained. Has decreased significantly. Of course, when the window portion 47 is provided and the window functional material is used (Experimental Examples 2-1 to 2-4), the case where the window portion 47 is not provided (Experimental Example 1-12) and other than the window functional material The same scraping state and adhesive strength as in the case of using the above materials (Experimental Examples 1-13 to 1-15) were also obtained.

From the results shown in Tables 1 and 2, the wound electrode body is housed inside the film-shaped exterior member, and the exterior member has a window portion containing a window functional material (non-porous molten fluororesin). When provided, the capacity maintenance characteristics and swelling characteristics of the secondary battery were improved while ensuring the physical durability characteristics and adhesive characteristics of the exterior member. Therefore, excellent battery characteristics were obtained in the secondary battery.

Although the present technology has been described above with reference to some embodiments and examples, the present technology is not limited to the embodiments described in one embodiment and examples, and various modifications can be made.

Specifically, for example, the case where the battery element has a wound structure has been described, but the structure of the battery element in the secondary battery of the present technology is not particularly limited. Specifically, the battery element may have another structure such as a laminated structure.

In addition, a secondary battery (lithium ion secondary battery) in which the capacity of the negative electrode can be obtained by storing and releasing lithium and a secondary battery (lithium metal secondary battery) in which the capacity of the negative electrode can be obtained by precipitation and dissolution of lithium have been described. The principle of obtaining the capacity of the negative electrode in the secondary battery of the present technology is not particularly limited. Specifically, for example, by making the capacity of the negative electrode material capable of occluding and releasing lithium smaller than the capacity of the positive electrode, the secondary battery can be obtained by adding the capacity due to occlusion and release of lithium and the capacity due to precipitation and dissolution of lithium. A secondary battery or the like that can obtain the capacity of the negative electrode may be used.

Further, the case where lithium is used as the electrode reactant has been described, but the present invention is not limited to this. The electrode reactant may be, for example, another Group 1 element in the long periodic table such as sodium (Na) and potassium (K), or a long periodic table such as magnesium (Mg) and calcium (Ca). It may be a group 2 element in, or it may be another light metal such as aluminum (Al). Further, the electrode reactant may be an alloy containing any one or more of the above-mentioned series of elements.

It should be noted that the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.

The present technology can also have the following configurations.
(1)
Battery elements containing positive and negative electrodes and electrolytes,
A secondary battery comprising the battery element and a film-like exterior member having a window portion containing a non-porous molten fluororesin.
(2)
The non-porous molten fluororesin includes a non-porous tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), a non-porous tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and a non-porous tetrafluoro. Containing at least one of ethylene-ethylene copolymer (ETFE),
The secondary battery according to (1) above.
(3)
The exterior member has an opening and
The window portion is formed by covering at least the opening with a film-shaped window member containing the non-porous molten fluororesin.
The secondary battery according to (1) or (2) above.
(4)
The window member has an area larger than the area of the opening and is attached to the exterior member via an adhesive.
The secondary battery according to (3) above.
(5)
A protective layer containing a breathable material is provided on the window member.
The secondary battery according to (3) or (4) above.
(6)
The thickness of the window member is 10 μm or more and 500 μm or less.
The secondary battery according to any one of (3) to (5) above.
(7)
The exterior member is
A first exterior member that covers the battery element from one side and
Including a second exterior member that covers the battery element from the other side,
The window portion is formed by adhering a part of the first exterior member and a part of the second exterior member to each other via a film-like window member containing the non-porous molten fluororesin. Has been
The secondary battery according to (1) or (2) above.
(8)
The window member is attached to each of the first exterior member and the second exterior member via an adhesive.
The secondary battery according to (7) above.
(9)
The thickness of the window member is 10 μm or more and 500 μm or less.
The secondary battery according to (7) or (8) above.
(10)
Lithium-ion secondary battery,
The secondary battery according to any one of (1) to (9) above.
(11)
The secondary battery according to any one of (1) to (10) above,
A control unit that controls the operation of the secondary battery,
A battery pack including a switch unit that switches the operation of the secondary battery in response to an instruction from the control unit.
(12)
The secondary battery according to any one of (1) to (10) above,
A conversion unit that converts the power supplied from the secondary battery into driving force,
A drive unit that drives according to the driving force,
An electric vehicle provided with a control unit that controls the operation of the secondary battery.
(13)
The secondary battery according to any one of (1) to (10) above,
One or more electrical devices supplied with power from the secondary battery, and
A power storage system including a control unit that controls power supply from the secondary battery to the electric device.
(14)
The secondary battery according to any one of (1) to (10) above,
A power tool provided with a moving part to which power is supplied from the secondary battery.
(15)
An electronic device provided with the secondary battery according to any one of (1) to (10) above as a power supply source.

This application claims priority based on Japanese Patent Application No. 2016-244512 filed at the Japan Patent Office on December 16, 2016, and this application is made by referring to all the contents of this application. Invite to.

Those skilled in the art may conceive of various modifications, combinations, sub-combinations, and changes, depending on design requirements and other factors, but they are the purpose of the appended claims and the scope of their equivalents. It is understood that it is included in.

Claims (10)

Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Secondary battery. The non-porous molten fluororesin includes a non-porous tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), a non-porous tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and a non-porous tetrafluoro. Containing at least one of ethylene-ethylene copolymer (ETFE),
The secondary battery according to claim 1. A protective layer containing a breathable material is provided on the window member.
The secondary battery according to claim 1 or 2 . The thickness of the window member is 10 μm or more and 500 μm or less.
The secondary battery according to any one of claims 1 to 3 . Lithium-ion secondary battery,
The secondary battery according to any one of claims 1 to 4 . With a secondary battery
A control unit that controls the operation of the secondary battery,
It is provided with a switch unit that switches the operation of the secondary battery according to the instruction of the control unit.
The secondary battery is
Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Battery pack. With a secondary battery
A conversion unit that converts the power supplied from the secondary battery into driving force,
A drive unit that drives according to the driving force,
It is equipped with a control unit that controls the operation of the secondary battery.
The secondary battery is
Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Electric vehicle. With a secondary battery
One or more electrical devices supplied with power from the secondary battery, and
It is provided with a control unit that controls the power supply from the secondary battery to the electric device.
The secondary battery is
Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Power storage system. With a secondary battery
It is equipped with a moving part to which power is supplied from the secondary battery.
The secondary battery is
Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Electric tool. Equipped with a secondary battery as a power supply source
The secondary battery is
Battery elements containing positive and negative electrodes and electrolytes,
In addition to accommodating the battery element, it is provided with a film-like exterior member having a window portion containing a non-porous molten fluororesin .
The exterior member has an opening and
The window portion is formed by covering the opening with a single-layer film-like window member containing the non-porous molten fluororesin.
The window member has an area larger than the area of the opening, and is attached to the exterior member via an adhesive by being arranged inside the exterior member.
Electronics.

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