阅读说明：本技术 锂离子二次电池用负极及锂离子二次电池 (Negative electrode for lithium ion secondary battery and lithium ion secondary battery ) 是由 浅川雄一郎 上坂进一 安托尼·拉弗勒-兰伯特 卡里姆·佐格希布 于 2018-04-27 设计创作，主要内容包括：一种锂离子二次电池,具备：正极；负极,包含环状化合物,并且该环状化合物包含第一环状化合物、第二环状化合物和第三环状化合物中的至少一种；以及电解液。(A lithium ion secondary battery is provided with: a positive electrode; a negative electrode that contains a cyclic compound, and the cyclic compound contains at least one of a first cyclic compound, a second cyclic compound, and a third cyclic compound; and an electrolyte.)

1. a lithium ion secondary battery is provided with:

A positive electrode;

A negative electrode that contains a cyclic compound, and the cyclic compound contains at least one of a first cyclic compound represented by the following formula (1), a second cyclic compound represented by the following formula (2), and a third cyclic compound represented by the following formula (3); and

An electrolyte solution is added to the electrolyte solution,

Chemical formula 1

Wherein X1 to X8 are each independently any one of an oxy group (-O-) and an imino group (-NH-), and R1 to R6 are each independently an ethylene group (-CH)₂-CH₂-) and a dicarbonyl group (-C (═ O) -), M1 to M4 each represent a metal element, Y1 to Y4 each represent a halogen element, and n1 to n4 each represent an integer.

2. The lithium-ion secondary battery according to claim 1,

Each of M1 to M4 is one of tin (Sn), titanium (Ti), silicon (Si), copper (Cu), manganese (Mn), iron (Fe), niobium (Nb), nickel (Ni), cobalt (Co), aluminum (Al), and zirconium (Zr).

3. The lithium-ion secondary battery according to claim 1 or 2,

Each of Y1 to Y4 is one of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

4. The lithium-ion secondary battery according to any one of claims 1 or 3,

And X1-X8 are all oxygen groups or all imino groups.

5. The lithium-ion secondary battery according to any one of claims 1 or 4,

The first cyclic compound is a compound represented by the following formula (4),

The second cyclic compound is a compound represented by the following formula (5),

the third cyclic compound is a compound represented by the following formula (6),

Chemistry 2

Wherein X9 to X16 are each an oxygen group or an imino group, M5 to M8 are each a metal element, Y5 to Y8 are each a halogen element, and n5 to n8 are each an integer.

6. The lithium-ion secondary battery according to any one of claims 1 or 5,

The anode further includes at least one of a carbon material and a metal-based material,

the weight ratio of the cyclic compound to the cyclic compound, the carbon material, and the metallic material is 0.01 to 0.99.

7. An anode for a lithium ion secondary battery, comprising:

A cyclic compound which is a cyclic compound having a cyclic structure,

And the cyclic compound includes at least one of a first cyclic compound represented by the following formula (1), a second cyclic compound represented by the following formula (2), and a third cyclic compound represented by the following formula (3),

Chemistry 3

In the formula, X1 to X8 each represent one of an oxy group (-O-) and an imino group (-NH-), R1 to R6 each represent one of an ethylene group (-CH2-CH2-) and a dicarbonyl group (-C (═ O) -), M1 to M4 each represent a metal element, Y1 to Y4 each represent a halogen element, and n1 to n4 each represent an integer.

Technical Field

The present technology relates to a negative electrode for a lithium ion secondary battery used for a lithium ion secondary battery, and a lithium ion secondary battery including the negative electrode for a lithium ion secondary battery.

Background

Since various electronic devices are becoming widespread, development of a lithium ion secondary battery that is small and lightweight and can achieve high energy density has been advanced as a power source.

A lithium ion secondary battery includes an electrolyte solution together with a positive electrode and a negative electrode, and the negative electrode contains a negative electrode active material or the like involved in charge and discharge reactions. Since the structure of the negative electrode greatly affects the battery characteristics, various studies have been made on the structure of the negative electrode.

Specifically, the negative electrode contains a cyclic polyether, a cryptic ether, and the like in order to suppress a decrease in battery characteristics during high-temperature storage (for example, see patent document 1). As the cyclic polyether, 4, 10-diaza-12-crown 4-ether or the like is used.

Disclosure of Invention

Electronic devices equipped with lithium ion secondary batteries have been increasingly higher in performance and multi-functional. Thereby, the frequency of use of the electronic device increases and the use environment of the electronic device expands. Therefore, there is still room for improvement in battery characteristics of lithium ion secondary batteries.

The present technology has been made in view of the above problems, and an object of the present technology is to provide a negative electrode for a lithium ion secondary battery and a lithium ion secondary battery, which can obtain excellent battery characteristics.

The negative electrode for a lithium ion secondary battery according to one embodiment of the present technology contains a cyclic compound, and the cyclic compound contains at least one of a first cyclic compound represented by the following formula (1), a second cyclic compound represented by the following formula (2), and a third cyclic compound represented by the following formula (3).

[ solution 1]

(X1-X8 each represent any one of an oxy group (-O-) and an imino group (-NH-) and R1-R6 each represent an ethylene group (-CH)₂-CH₂-) and dicarbonyl (-C (═ O) -). M1 to M4 are each a metal element. Y1 to Y4 are halogen elements, respectively. n1 to n4 are integers, respectively. ) A lithium-ion secondary battery according to an embodiment of the present technology includes a positive electrode, a negative electrode, and an electrolyte solution, and the negative electrode has the same configuration as the negative electrode for a lithium-ion secondary battery according to the above-described embodiment of the present technology.

According to the negative electrode for a lithium ion secondary battery or the lithium ion secondary battery of the present technology, since the negative electrode contains the cyclic compound and the cyclic compound contains at least one of the first cyclic compound, the second cyclic compound, and the third cyclic compound, excellent battery characteristics can be obtained.

The effects of the present technology are not limited to the effects described herein, and may be any of a series of effects described below in connection with the present technology.

Drawings

Fig. 1 is a sectional view showing a structure of a lithium-ion secondary battery (cylindrical type) according to an embodiment of the present technology.

Fig. 2 is an enlarged sectional view of a main portion of the lithium-ion secondary battery shown in fig. 1.

Fig. 3 is a perspective view showing the structure of another lithium ion secondary battery (laminate film type) according to an embodiment of the present technology.

Fig. 4 is a cross-sectional view showing an enlarged configuration of a main portion of the lithium-ion secondary battery shown in fig. 3.

Fig. 5 is a sectional view showing the structure of a secondary battery (coin type) for testing.

Detailed Description

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

1. Lithium ion secondary battery and negative electrode for lithium ion secondary battery (cylindrical type)

1-1. constitution

1-2. actions

1-3. method of manufacture

1-4. action and Effect

2. Lithium ion secondary battery and negative electrode for lithium ion secondary battery (laminate film type)

2-1. formation

2-2. actions

2-3. preparation method

2-4. action and Effect

3. Lithium ion secondary battery and use of negative electrode for lithium ion secondary battery

(1) lithium ion secondary battery and negative electrode (cylindrical type) for lithium ion secondary battery

a lithium-ion secondary battery according to an embodiment of the present technology will be described. The negative electrode for a lithium-ion secondary battery according to one embodiment of the present technology is a part (a component) of a lithium-ion secondary battery described below, and therefore the negative electrode for a lithium-ion secondary battery will be described below in combination.

Hereinafter, the lithium ion secondary battery according to an embodiment of the present technology is simply referred to as a "lithium ion secondary battery", and the negative electrode for a lithium ion secondary battery according to an embodiment of the present technology is simply referred to as a "negative electrode".

The lithium ion secondary battery described here is, for example, a secondary battery that obtains a battery capacity (capacity of the negative electrode 22 described later) by utilizing an occlusion and release phenomenon of lithium.

In addition, as to a series of specific examples, that is, a plurality of alternatives of materials, forming methods, and the like, which will be described below as appropriate, only one of them may be used, or two or more of them may be combined with each other.

(1-1. constitution)

Fig. 1 shows a sectional structure of a lithium ion secondary battery, and fig. 2 is an enlarged view of the sectional structure of a main portion (wound electrode assembly 20) of the lithium ion secondary battery shown in fig. 1. However, fig. 2 shows only a part of the wound electrode body 20.

As shown in fig. 1, the lithium ion secondary battery is, for example, a cylindrical lithium ion secondary battery in which a battery cell (wound electrode assembly 20) is housed inside a cylindrical battery can 11.

Specifically, the lithium ion secondary battery includes, for example, a pair of insulating plates 12 and 13 and a wound electrode assembly 20 inside a battery can 11. The wound electrode body 20 is, for example, a structure in which a cathode 21 and an anode 22 are laminated on each other via a separator 23, and then the cathode 21, the anode 22, and the separator 23 are wound. The wound electrode body 20 is impregnated with an electrolyte solution as a liquid electrolyte.

The battery can 11 has, for example, a hollow cylindrical configuration with one end closed and the other end open, and contains a metal material such as iron. However, the surface of the battery can 11 may be plated with a metal material such as nickel. The insulating plates 12 and 13 are arranged to extend in a direction intersecting the wound peripheral surface of the wound electrode body 20, for example, and sandwich the wound electrode body 20 therebetween.

in the open end portion of the battery can 11, for example, the battery cover 14, the safety valve mechanism 15, and the thermistor unit (PTC unit) 16 are caulked by the gasket 17, and thus the open end portion of the battery can 11 is sealed. The battery cover 14 is formed of the same material as that of the battery can 11, for example. A safety valve mechanism 15 and a thermistor unit 16 are provided inside the battery cover 14, and the safety valve mechanism 15 is electrically connected to the battery cover 14 through the thermistor unit 16. When the internal pressure of the battery can 11 is equal to or higher than a fixed value due to, for example, an internal short circuit or external heating in the safety valve mechanism 15, the disk plate 15A is reversed, and thus the electrical connection between the battery cover 14 and the wound electrode assembly 20 is cut off. In order to prevent abnormal heat generation due to a large current, the resistance of the thermistor unit 16 increases according to an increase in temperature. The spacer 17 is made of an insulating material, for example. However, the surface of the gasket 17 may be coated with asphalt, for example.

A center pin 24, for example, is inserted into a space 20C provided at the winding center of the wound electrode body 20. However, the center pin 24 may be omitted. The positive electrode 21 is connected to a positive electrode lead 25, and the positive electrode lead 25 contains a conductive material such as aluminum, for example. The positive electrode lead 25 is electrically connected to the battery lid 14 through, for example, the safety valve mechanism 15. The negative electrode 22 is connected to a negative electrode lead 26, and the negative electrode lead 26 contains a conductive material such as nickel. The negative electrode lead 26 is electrically connected to the battery can 11, for example.

[ Positive electrode ]

as shown in fig. 2, the positive electrode 21 includes, for example, a positive electrode current collector 21A and a positive electrode active material layer 21B provided on the positive electrode current collector 21A. The positive electrode active material layer 21B may be provided on only one surface of the positive electrode current collector 21A, or may be provided on both surfaces of the positive electrode current collector 21A. Fig. 2 shows, for example, a case where the positive electrode active material layer 21B is provided on both surfaces of the positive electrode current collector 21A.

(Positive electrode collector)

The positive electrode current collector 21A contains a conductive material such as aluminum, for example.

(Positive electrode active Material layer)

The positive electrode active material layer 21B contains a positive electrode material capable of occluding and releasing lithium as a positive electrode active material. However, the positive electrode active material layer 21B further contains other materials such as a positive electrode binder and a positive electrode conductive agent.

(Positive electrode Material)

The positive electrode material contains, for example, a lithium compound, which is a generic name of a compound containing lithium as a constituent element. Thereby enabling a high energy density to be obtained. The type of the lithium compound is not particularly limited, but examples thereof include a lithium composite oxide and a lithium phosphate compound.

The lithium composite oxide is a generic term for oxides containing lithium and one or two or more other elements as constituent elements, and has a crystal structure such as a layered rock salt type and a spinel type, for example. The lithium phosphate compound is a generic term for a phosphate compound containing lithium and one or two or more other elements as constituent elements, and has a crystal structure such as an olivine type, for example.

The other element is an element other than lithium. The kind of the other elements is not particularly limited, but among them, elements belonging to groups 2 to 15 in the long period periodic table are preferable. Thereby enabling a high voltage to be obtained. Specifically, the other elements are, for example, nickel, cobalt, manganese, iron, and the like.

The lithium composite oxide having a crystal structure of a layered rock salt type is, for example, LiNiO₂、LiCoO₂、LiCo_0.98Al_0.01Mg_0.01O₂、LiNi_0.5Co_0.2Mn_0.3O₂、LiNi_0.8Co_0.15Al_0.05O₂、LiNi_0.33Co_0.33Mn_0.33O₂、Li_1.2Mn_0.52Co_0.175Ni_0.1O₂And Li_1.15(Mn_0.65Ni_0.22Co_0.13)O₂And the like. Lithium composite oxides having a spinel-type crystal structure are, for example, LiMn₂O₄And the like. The lithium phosphate compound having an olivine-type crystal structure is, for example, LiFePO₄、LiMnPO₄、LiFe_0.5Mn_0.5PO₄And LiFe_0.3Mn_0.7PO₄And the like.

(Positive electrode Binder and Positive electrode conductive agent)

The positive electrode binder includes, for example, synthetic rubber, a polymer compound, and the like. Examples of the synthetic rubber include styrene butadiene rubber and the like. Examples of the polymer compound include polyvinylidene fluoride and polyimide.

The positive electrode conductive agent contains a conductive material such as a carbon material. Examples of the carbon material include graphite, carbon black, acetylene black, and ketjen black. However, the positive electrode conductive agent may be a metal material, a conductive polymer, or the like.

[ negative electrode ]

As shown in fig. 2, the anode 22 includes, for example, an anode current collector 22A and an anode active material layer 22B provided on the anode current collector 22A. The negative electrode active material layer 22B may be provided on only one surface of the negative electrode current collector 22A, or may be provided on both surfaces of the negative electrode current collector 22A. For example, fig. 2 shows a case where the anode active material layer 22B is provided on both surfaces of the anode current collector 22A.

(negative electrode collector)

the negative electrode current collector 22A contains a conductive material such as copper, for example. Preferably, the surface of the negative electrode current collector 22A is roughened by an electrolytic method or the like. This improves the adhesion to the negative electrode active material layer 22B of the negative electrode current collector 22A by the anchor effect.

(negative electrode active material layer)

The negative electrode active material layer 22B contains a negative electrode material capable of occluding and releasing lithium as a negative electrode active material. However, the anode active material layer 22B may also contain other materials such as an anode binder and an anode conductive agent, for example.

In order to prevent lithium metal from being accidentally deposited on the surface of the negative electrode 22 during charging, the capacity of the negative electrode material that can be charged is preferably larger than the discharge capacity of the positive electrode 21. That is, it is preferable that the electrochemical equivalent of the anode material is larger than that of the cathode 21.

(negative electrode Material: Cyclic Compound)

The negative electrode material contains a cyclic compound having a specific cyclic structure. Specifically, the cyclic compound includes one or two or more of a first cyclic compound represented by the following formula (1), a second cyclic compound represented by the following formula (2), and a third cyclic compound represented by the following formula (3). The first cyclic compound may be one kind or two or more kinds. This also applies to the second cyclic compound and the third cyclic compound, respectively.

[ solution 2]

(X1 to X8 each represents one of an oxy group and an imino group; R1 to R6 each represents one of an ethylene group and a dicarbonyl group; M1 to M4 each represents a metal element; Y1 to Y4 each represents a halogen element; n1 to n4 each represents an integer.)

The cyclic compound has a cyclic structure including two or more dicarbonyl groups, and more specifically, has cyclic structures represented by formulas (1) to (3). Specifically, no metal atom is introduced into the cyclic skeleton represented by formula (1), and a metal atom is introduced into the cyclic skeleton represented by formula (2) or formula (3) by one or both of coordinate bonding and covalent bonding (M1 to M4). The detailed configurations of the first cyclic compound, the second cyclic compound, and the third cyclic compound are described later.

The reason why the anode 22 contains the cyclic compound is because the cyclic compound functions as an anode material in the same manner as a carbon material or the like described later, and expansion and contraction of the anode active material layer 22B are suppressed by the cyclic compound during charge and discharge, as compared with the case where the anode 22 does not contain the cyclic compound.

Specifically, the cyclic compound can store and release lithium by utilizing the internal space (ligand field) of the cyclic skeleton. Therefore, the cyclic compound can function as a negative electrode material, as in the case of a carbon material or the like. The cyclic compound can expand and contract like a spring by utilizing the elasticity of the cyclic skeleton. Therefore, during charge and discharge, the expansion and contraction phenomenon of the negative electrode active material layer 22B is alleviated by the elasticity of the cyclic compound, and therefore the negative electrode active material layer 22B is less likely to expand and contract.

(first Cyclic Compound)

As shown in formula (1), the first cyclic compound is a compound having a cyclic skeleton including two or more dicarbonyl groups, and no metal atom is introduced into the cyclic skeleton. That is, the first cyclic compound is an organic compound in which an inorganic portion (metal compound) is not introduced into an organic portion (cyclic skeleton).

As described above, X1 to X8 each may be an oxy group or an imino group, and is not particularly limited. That is, X1 to X8 may all be oxy groups, X1 to X8 may all be imino groups, and X1 to X8 may be some oxy groups and some imino groups.

Among them, X1 to X8 are preferably all oxygen groups or all imino groups. This makes it easier to suppress expansion and contraction of the negative electrode active material layer 22B during charge and discharge of the first cyclic compound.

As described above, R1 and R2 each may be any of an ethylene group and a dicarbonyl group, and are not particularly limited. That is, both R1 and R2 may be ethylene, both R1 and R2 may be dicarbonyl, and one of R1 and R2 may be ethylene and the other may be dicarbonyl. Thus, the first cyclic compound has 2 to 4 dicarbonyl groups.

(second Ring Compound)

As shown in formula (2), the second cyclic compound has a cyclic oxygen skeleton including two or more dicarbonyl groups, and metal atoms (M1 and M2) are introduced into the cyclic oxygen skeleton by coordinate bonding. That is, the second cyclic compound is an organic-inorganic hybrid compound in which an inorganic portion (metal compound) is introduced into an organic portion (cyclic oxygen skeleton).

In the second cyclic compound, a metal atom is coordinately bound to two oxygen atoms located on both sides of R3 (M1), and a metal atom is coordinately bound to two oxygen atoms located on both sides of R4 (M2). However, the metal atom (M1) was covalently bonded with n1 halogen atoms (Y1), and the metal atom (M2) was covalently bonded with n2 halogen atoms (Y2).

As described above, since the second cyclic compound has a metal atom (M1, M2) introduced into the cyclic oxygen skeleton by coordinate bonding, the second cyclic compound is advantageous over the first cyclic compound having no metal atom introduced into the cyclic skeleton. Specifically, the anode 22 becomes easy to occlude and release lithium by the electrochemical capacity of the metal atom, and the anode 22 becomes high in potential by the coordination potential of the metal atom (metal component).

The details regarding R3 and R4, respectively, are the same as those regarding R1 and R2, respectively. That is, since R3 and R4 each may be any of an ethylene group and a dicarbonyl group, and are not particularly limited, the second cyclic compound has 2 to 4 dicarbonyl groups.

As described above, M1 and M2 each may be a metal element, and are not particularly limited. More specifically, as described above, each of M1 and M2 is not particularly limited as long as it is a metal atom (metal element) that can coordinate to two oxygen atoms. The kind of M1 and the kind of M2 may be the same as or different from each other, for example.

Specifically, examples of the metal element include tin (Sn), titanium (Ti), silicon (Si), copper (Cu), manganese (Mn), iron (Fe), niobium (Nb), nickel (Ni), cobalt (Co), aluminum (Al), and zirconium (Zr). Thus, the metal atoms (M1, M2) are easily coordinated to the cyclic oxygen skeleton. This makes it easy to suppress expansion and contraction of the negative electrode active material layer 22B during charge and discharge of the first cyclic compound, and the potential of the negative electrode 22 becomes sufficiently high.

As described above, Y1 and Y2 each may be a halogen element, and are not particularly limited. The kind of Y1 and the kind of Y2 may be the same as or different from each other, for example. The number of n 1Y 1 may be, for example, only one, or two or more. In this case, the same applies to the n 2Y 2.

Specifically, Y1 and Y2 are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the like, respectively. Thereby, the metal atom (M1, M2) is easily coordinated to the cyclic oxygen skeleton. This makes it easy to suppress expansion and contraction of the negative electrode active material layer 22B during charge and discharge of the first cyclic compound, and the potential of the negative electrode 22 is sufficiently high.

n1 is the number of Y1 bound to M1, and the value of n1 is determined by the type of M1. n2 is the number of Y2 bound to M2, and the value of n2 is determined by the type of Y2. The value of n1 and the value of n2 may be the same as or different from each other, for example.

As described above, the value of n1 is not particularly limited as long as it is an integer determined according to the type of M1, and is, for example, 2 or 4. As described above, the value of n2 is not particularly limited as long as it is an integer determined according to the type of M2, and is, for example, 2 or 4.

(third Cyclic Compound)

The third cyclic compound is a compound having a cyclic nitrogen skeleton containing two or more dicarbonyl groups, and metal atoms (M3 and M4) are introduced into the cyclic nitrogen skeleton by coordination bonding or covalent bonding, as shown in formula (3). That is, the third cyclic compound is an organic-inorganic hybrid compound in which an inorganic portion (metal compound) is introduced into an organic portion (cyclic nitrogen skeleton) as in the second cyclic compound.

In the third cyclic compound, a metal atom is covalently bonded to two nitrogen atoms located on both sides of R5 (M3), and a metal atom is covalently bonded to two nitrogen atoms located on both sides of R6 (M4). In this case, a metal atom (M3) is coordinately bound to a nitrogen atom near one of two nitrogen atoms located on both sides of R5, and a metal atom (M3) is coordinately bound to a nitrogen atom near the other nitrogen atom. Further, a metal atom (M4) is coordinately bonded to a nitrogen atom near one of two nitrogen atoms located on both sides of R6, and a metal atom (M4) is coordinately bonded to a nitrogen atom near the other nitrogen atom. Wherein the metal atom (M3) is bonded to n3 halogen atoms (Y3), and the metal atom (M4) is bonded to n4 halogen atoms (Y4).

As described above, in the third cyclic compound, the metal atom (M3, M4) is introduced into the cyclic nitrogen skeleton by coordinate bonding and covalent bonding, and therefore, the same advantages as those of the second cyclic compound in which the metal atom (M1, M2) is introduced into the cyclic nitrogen skeleton by coordinate bonding can be obtained.

The details for R5 and R6, respectively, are the same as for R1 and R2, respectively. That is, since R5 and R6 each may be any of an ethylene group and a dicarbonyl group, and are not particularly limited, the third cyclic compound has 2 to 4 dicarbonyl groups.

The details for M3 and M4, respectively, are the same as for M1 and M2, respectively. That is, as described above, each of M3 and M4 may be a metal atom (metal element) which can be covalently bonded to two nitrogen atoms and can be coordinately bonded to the other two nitrogen atoms, and is not particularly limited. The kind of M3 and the kind of M4 may be the same as or different from each other, for example.

The details for Y3 and Y4, respectively, are the same as the details for Y1 and Y2, respectively. The kind of Y1 and the kind of Y2 may be the same as or different from each other, for example. The number of n 1Y 1 and the number of n 2Y 2 may be one, or two or more, respectively.

The details for n3 and n4, respectively, are the same as for n1 and n2, respectively. n3 is the number of Y3 bound to M3, the value of n3 is determined by the type of M3, and n4 is the number of Y4 bound to M4, the value of n4 is determined by the type of M4.

(specific examples of the Cyclic Compound)

Among them, the first cyclic compound is preferably a compound represented by the following formula (4). Preferably, the second cyclic compound is a compound represented by the following formula (5). Preferably, the third cyclic compound is a compound represented by the following formula (6). This makes the cyclic compound more likely to expand and contract, and the anode active material layer 22B is less likely to expand and contract during charge and discharge.

[ solution 3]

(X9 to X16 each represents one of an oxy group and an imino group; M5 to M8 each represents a metal element; Y5 to Y8 each represents a halogen element; n5 to n8 each represents an integer.)

The compound represented by the formula (4) is a cyclic nonmetallic compound in which R1 and R2 are ethylene groups, respectively, in the first cyclic compound represented by the formula (1).

Specifically, the cyclic nonmetal complex compound is, for example, a compound represented by the following formula (4-1) and formula (4-2).

[ solution 4]

The compound represented by the formula (5) is a crown ether type metal complex compound in which R3 and R4 are each an ethylene group in the second cyclic compound represented by the formula (2). The details of M5, M6, Y5, Y6, n5, and n6 are the same as those of M1, M2, Y1, Y2, n1, and n2, respectively.

Examples of the crown ether type metal complex compounds include compounds represented by the following formulae (5-1) to (5-12). In addition, the expressions (5-1) to (5-11) respectively show, for example, the case where Y5 and Y6 respectively shown in the expression (5) are chlorine. However, as described above, Y5 and Y6 may be fluorine, bromine, or iodine, respectively. Specifically, for example, as shown in formulas (5 to 12), Y5 and Y6 may be fluorine, respectively.

[ solution 5]

[ solution 6]

The compound represented by the formula (6) is an aza crown ether type metal complex compound in which R5 and R6 are each an ethylene group in the third cyclic compound represented by the formula (3). The details for M7, M8, Y7, Y8, n7 and n8, respectively, are for example the same as for M1, M2, Y1, Y2, n1 and n2, respectively.

Examples of the azacrown ether type metal complex compounds include compounds represented by the following formulae (6-1) to (6-12). In addition, the expressions (6-1) to (6-11) respectively show, for example, the case where Y7 and Y8 respectively shown in the expression (6) are chlorine. However, as described above, Y7 and Y8 may be fluorine, bromine, or iodine, respectively. Specifically, for example, as shown in formulas (6 to 12), Y7 and Y8 may be fluorine, respectively.

[ solution 7]

[ solution 8]

(other negative electrode Material)

The negative electrode material may contain, for example, the cyclic compound and another negative electrode material. The kind of other material is not particularly limited, but examples thereof include carbon materials and metal materials.

The carbon material is a generic term for a material containing carbon as a constituent element. When lithium is occluded and released, the crystal structure of the carbon material hardly changes, and therefore a high energy density can be stably obtained. In addition, the carbon material also functions as an anode conductive agent, and thus the conductivity of the anode active material layer 22B is improved.

Examples of the carbon material include graphitizable carbon, graphite, and the like. However, the (002) plane spacing in the non-graphitizable carbon is preferably 0.37nm or more, and the (002) plane spacing in the graphite is preferably 0.34nm or less.

more specifically, examples of the carbon material include thermally decomposed carbons, cokes, glassy carbon fibers, sintered organic polymer compounds, activated carbon, and carbon blacks. The coke includes, for example, pitch coke, needle coke, petroleum coke, and the like. The organic polymer compound sintered body is a sintered product obtained by sintering (carbonizing) a polymer compound such as a phenol resin or a furan resin at an appropriate temperature. In addition, the carbon material may be, for example, low crystalline carbon after heat treatment at a temperature of about 1000 ℃ or lower, or amorphous carbon. The shape of the carbon material is, for example, a fiber shape, a spherical shape, a granular shape, a scaly shape, or the like.

The metal-based material is a generic term for a material containing one or two or more of a metal element and a semimetal element as a constituent element. Thereby enabling a high energy density.

The metal-based material may be a simple substance, an alloy, a compound, a mixture of two or more of them, or a material containing one or two or more phases of them. However, the alloy includes not only a compound of two or more metal elements but also a compound containing one or more metal elements and one or more semimetal elements. In addition, the alloy may contain one or two or more non-metallic elements. The structure of the metallic material is, for example, a solid solution, a eutectic crystal (eutectic mixture), an intermetallic compound, or a coexisting material of two or more of them.

The metal element and the semimetal element can form an alloy with lithium, respectively. Specifically, the metal element and the semimetal element are, for example, magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, lead, bismuth, cadmium, silver, zinc, hafnium, zirconium, yttrium, palladium, platinum and the like.

Among them, silicon and tin are preferable, and silicon is more preferable. The occlusion and release capacity of lithium is better, whereby a remarkably high energy density is obtained.

Specifically, the metal-based material may be a simple substance of silicon, a silicon alloy, a silicon compound, a simple substance of tin, a tin alloy, a tin compound, a mixture of two or more of them, or a material containing one or more phases of them. The simple substance described herein is generally referred to as a simple substance, and thus the simple substance may contain a trace amount of impurities. That is, the purity of the simple substance is not necessarily limited to 100%.

The silicon alloy contains, for example, tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, chromium, and the like as constituent elements other than silicon. The silicon compound contains, for example, carbon and oxygen as constituent elements other than silicon. The compound of silicon may contain the constituent elements described for the silicon alloy as constituent elements other than silicon, for example.

Silicon alloys and silicon compounds, e.g. SiB₄、SiB₆、Mg₂Si、Ni₂Si、TiSi₂、MoSi₂、CoSi₂、NiSi₂、CaSi₂、CrSi₂、Cu₅Si、FeSi₂、MnSi₂、NbSi₂、TaSi₂、VSi₂、WSi₂、ZnSi₂、SiC、Si₃N₄、Si₂N₂O and SiO_v(0 < v ≦ 2), and the like. However, v can also be in the range 0.2 < v < 1.4, for example.

the tin alloy contains, for example, silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, chromium, and the like as a constituent element other than tin. The tin compound contains, for example, carbon, oxygen, and the like as a constituent element other than tin. The tin compound may contain, for example, the constituent elements described for the tin alloy as constituent elements other than tin.

Tin alloys and tin compounds, e.g. SnO_w(0＜w≦2)、SnSiO₃And Mg₂Sn, and the like.

Among them, the anode material preferably contains one or both of a carbon material and a metal-based material together with a cyclic compound. In this case, the negative electrode material may contain the carbon material together with the cyclic compound, may contain the metal material together with the cyclic compound, or may contain the carbon material and the metal material together with the cyclic compound. Thereby, a high theoretical capacity (battery capacity) can be obtained, and it is difficult for the anode active material layer 22B to sufficiently expand and contract at the time of charge and discharge.

The mixing ratio of the cyclic compound to the carbon material and the metal material is not particularly limited. Among these, the weight ratio of the cyclic compound to the cyclic compound, the carbon material and the metal material (i.e., the weight of the cyclic compound/(the weight of the cyclic compound + the weight of the carbon material + the weight of the metal material)) is preferably 0.01 to 0.99, and more preferably 0.05 to 0.90. This sufficiently suppresses expansion and contraction of the negative electrode active material layer 22B during charge and discharge, and enables a high battery capacity to be obtained.

(negative electrode Binder and negative electrode conductive agent)

The details of the anode binder are the same as those of the cathode binder, for example. The details of the anode conductive agent are the same as those of the cathode conductive agent, for example.

(method of Forming negative electrode active Material layer)

The method of forming the anode active material layer 22B is not particularly limited, but examples thereof include a coating method, a vapor phase method, a liquid phase method, a spray method, and a firing method (sintering method). The coating method is a method of coating the negative electrode current collector 22A with a solution in which a mixture of a negative electrode active material in the form of particles (powder) and a negative electrode binder or the like is dissolved or dispersed in an organic solvent or the like, for example. The vapor phase method includes, for example, a physical deposition method and a chemical deposition method, and more specifically, a vacuum deposition method, a sputtering method, an ion plating method, a laser ablation method, a thermal chemical vapor deposition method, a chemical vapor deposition method (CVD), a plasma chemical vapor deposition method, and the like. The liquid phase method is, for example, electrolytic plating and electroless plating. The meltblowing method is a method of blowing a negative electrode active material in a molten state or a semi-molten state to the negative electrode current collector 22A. The firing method is, for example, a method in which the solution is applied to the negative electrode current collector 22A by a coating method, and then the solution (coating film) is subjected to heat treatment at a temperature higher than the melting point of the negative electrode binder or the like, more specifically, an atmospheric firing method, a reactive firing method, a thermocompression firing method, or the like.

[ separator ]

As shown in fig. 2, the separator 23 is interposed between the positive electrode 21 and the negative electrode 22, for example, and prevents short-circuiting caused by contact between the electrodes while allowing lithium ions to pass therethrough. The separator 23 may be a laminated film including a porous film such as a synthetic resin or a ceramic, and two or more kinds of porous films laminated on each other. The synthetic resin is, for example, polyethylene or the like.

in particular, the separator 23 may include, for example, the porous film (base material layer) and a polymer compound layer provided on the base material layer. The polymer compound layer may be provided on only one surface of the base material layer, or may be provided on both surfaces of the base material layer. Since the adhesion of the separator 23 to each of the cathode 21 and the anode 22 is improved, the wound electrode body 20 is less likely to be bent. This suppresses the decomposition reaction of the electrolyte solution and also suppresses leakage of the electrolyte solution into which the base material layer is impregnated. Therefore, even if charge and discharge are repeated, the resistance of the lithium ion secondary battery is less likely to increase, and the lithium ion secondary battery is less likely to swell.

The polymer compound layer contains, for example, a polymer compound such as polyvinylidene fluoride. Thereby having excellent physical strength and stable electrochemical properties. The polymer compound layer may contain insulating particles such as inorganic particles, for example. Thereby improving safety. The kind of the inorganic particles is not particularly limited, but examples thereof include alumina, aluminum nitride, and the like.

[ electrolyte ]

As described above, the electrolyte is impregnated in the wound electrode body 20. Therefore, the electrolyte, for example, infiltrates into the separator 23 and infiltrates into the positive electrode 21 and the negative electrode 22, respectively.

The electrolyte solution includes a solvent and an electrolyte salt. However, the electrolyte may further contain various additives, for example.

(solvent)

The solvent includes, for example, a nonaqueous solvent (organic solvent), and the electrolytic solution including the nonaqueous solvent is a so-called nonaqueous electrolytic solution. Examples of the nonaqueous solvent include cyclic carbonates, chain carboxylates, lactones, and nitrile (mononitrile) compounds. Thereby, excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained.

Examples of the cyclic carbonate include ethylene carbonate, propylene carbonate, and butylene carbonate. Examples of the chain carbonate include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and propyl methyl carbonate. Examples of the chain carboxylic acid ester include methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, methyl isobutyrate, methyl pivalate, and ethyl pivalate. Examples of the lactone include γ -butyrolactone and γ -valerolactone. The nitrile compound is, for example, acetonitrile, methoxyacetonitrile, 3-methoxypropionitrile, or the like.

Examples of the nonaqueous solvent include 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1, 3-dioxolane, 4-methyl-1, 3-dioxolane, 1, 3-dioxane, 1, 4-dioxane, N-dimethylformamide, N-methylpyrrolidone, N-methyloxazolidinone, N' -dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, and dimethyl sulfoxide. Whereby the same advantages can be obtained.

In addition, the nonaqueous solvent may be an unsaturated cyclic carbonate, a halogenated carbonate, a sulfonate, an acid anhydride, a polyvalent nitrile compound, a diisocyanate compound, a phosphate, or the like. Thereby improving the chemical stability of the electrolyte.

Examples of the unsaturated cyclic carbonate include vinylene carbonate (1, 3-dioxol-2-one), vinyl ethylene carbonate (4-vinyl-1, 3-dioxolan-2-one), and methylene ethylene carbonate (4-methylene-1, 3-dioxolan-2-one). Examples of the halogenated carbonates include 4-fluoro-1, 3-dioxolan-2-one, 4, 5-difluoro-1, 3-dioxolan-2-one, fluoromethyl methyl carbonate, difluoromethyl methyl carbonate and difluoromethyl methyl carbonate. The sulfonic acid ester is, for example, 1, 3-propane sultone, 1, 3-propene sultone, etc. Examples of the acid anhydride include succinic anhydride, ethane disulfonic anhydride, and sulfobenzoic anhydride. Examples of the polyvalent nitrile compound include succinonitrile and the like. Diisocyanate compounds such as OCN-C₆H₁₂-NCO and the like. Examples of the phosphate ester include trimethyl phosphate.

(electrolyte salt)

The electrolyte salt is, for example, a lithium salt. However, the electrolyte salt may also include, for example, other salts other than lithium salts. Other salts are, for example, salts of light metals other than lithium, and the like.

The lithium salt is, for example, lithium hexafluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium bis (fluorosulfonyl) amide (LiN (SO)₂F)₂) Lithium bis (trifluoromethanesulfonyl) amide (LiN (CF)₃SO₂)₂) Lithium difluorophosphate (LiPF)₂O₂) And lithium fluorophosphate (Li)₂PFO₃) And the like.

The content of the electrolyte salt is not particularly limited, but is, for example, 0.3 to 3.0mol/kg relative to the solvent.

< 1-2 > actions

The lithium ion secondary battery operates as follows, for example. At the time of charging, lithium ions are released from the cathode 21, and the lithium ions are occluded by the anode 22 through the electrolytic solution. At the time of discharge, lithium ions are released from the negative electrode 22, and the lithium ions are occluded by the positive electrode 21 through the electrolytic solution.

< 1-3 > method for manufacturing >

The lithium ion secondary battery is manufactured, for example, by the following steps.

[ production of Positive electrode ]

First, a positive electrode active material is mixed with a positive electrode binder, a positive electrode conductive agent, and the like as necessary to form a positive electrode mixture. Next, the positive electrode mixture is dispersed or dissolved in an organic solvent or the like to obtain a paste-like positive electrode mixture slurry. Finally, the positive electrode active material layer 21B is formed by applying the positive electrode mixture slurry to both surfaces of the positive electrode current collector 21A and then drying the positive electrode mixture slurry. Here, the positive electrode active material layer 21B may be compression-molded using a roll press or the like. In this case, the positive electrode active material layer 21B may be heated, or compression molding may be repeated a plurality of times.

[ production of negative electrode ]

the negative electrode active material layer 22B is formed on both surfaces of the negative electrode current collector 22A by the same steps as those of the positive electrode 21. Specifically, a negative electrode active material containing a cyclic compound is mixed with a negative/positive electrode binder, a negative electrode conductive agent, and the like as needed to form a negative electrode mixture, and then the negative electrode mixture is dispersed in an organic solvent or the like to obtain a paste-like negative electrode mixture slurry. Next, the negative electrode mixture slurry is applied to both surfaces of the negative electrode current collector 22A, and then the negative electrode mixture slurry is dried. Thus, the anode 22 is produced by forming the anode active material layer 22B. After that, the anode active material layer 22B may also be compression molded.

[ preparation of electrolyte ]

After the electrolyte salt is added to the solvent, the solvent is stirred. Thereby, the electrolyte salt is dissolved to prepare an electrolytic solution.

[ Assembly of lithium ion Secondary Battery ]

First, the cathode lead 25 is connected to the cathode current collector 21A by welding or the like, and the anode lead 26 is connected to the anode current collector 22A by welding or the like. Next, the cathode 21 and the anode 22 are laminated on each other via the separator 23, and then the cathode 21, the anode 22, and the separator 23 are wound to form a wound body. Next, the center pin 24 is inserted into the space 20C provided in the winding center of the wound body.

Next, the wound body is housed together with the insulating plates 12 and 13 in the battery case 11 with the wound body sandwiched between the pair of insulating plates 12 and 13. In this case, the positive electrode lead 25 is connected to the safety valve mechanism 15 by welding or the like, and the negative electrode lead 26 is connected to the battery can 11 by welding or the like. Next, the electrolyte is injected into the battery can 11 to infiltrate the wound body with the electrolyte. Thereby, the positive electrode 21, the negative electrode 22, and the separator 23 are impregnated with the electrolyte solution, respectively, to form the wound electrode assembly 20.

Finally, the battery cover 14, the safety valve mechanism 15, and the thermistor unit 16 are attached to the open end of the battery can 11 by caulking the open end of the battery can 11 through the gasket 17. Thereby, the wound electrode assembly 20 is enclosed inside the battery can 11, and the lithium-ion secondary battery is completed.

Action and Effect (1-4)

According to the cylindrical lithium ion secondary battery, the negative electrode 22 contains a cyclic compound, that is, any one or two or more of the first cyclic compound, the second cyclic compound, and the third cyclic compound. In this case, as described above, compared with the case where the anode 22 does not contain the cyclic compound, the cyclic compound functions as an anode active material (anode material) and suppresses expansion and contraction of the anode active material layer 22B during charge and discharge. Therefore, excellent battery characteristics can be obtained.

The case where the anode 22 does not contain a cyclic compound means not only the case where the anode 22 does not contain any of the first cyclic compound, the second cyclic compound, and the third cyclic compound, but also the case where the anode 22 does not contain another cyclic compound similar to the cyclic compound. Examples of the other cyclic compounds include oxygen-containing cyclic compounds, nitrogen-containing cyclic compounds, and oxygen-nitrogen-containing cyclic compounds. Examples of the oxygen-containing cyclic compound include crown ether, cryptic ether and the like. Examples of the nitrogen-containing cyclic compound include tetraazacyclododecane and the like. The oxygen-nitrogen-containing cyclic compound is, for example, 4, 10-diaza-12-crown 4-ether or the like.

In particular, when each of M1 to M4 is tin or the like, the metal atoms (M1 to M4) are easily coordinated to the cyclic skeleton (cyclic oxygen skeleton and cyclic nitrogen skeleton). Therefore, at the time of charge and discharge, expansion and contraction of the anode active material layer 22B become easily suppressed, and the potential of the anode 22 becomes extremely high, so that a better effect can be obtained.

Further, when Y1 to Y4 are each fluorine or the like, a metal atom (M1 to M4) is easily coordinated to a cyclic skeleton (a cyclic oxygen skeleton and a cyclic nitrogen skeleton) as in the case where M1 to M4 are each tin or the like, and a further effect can be obtained.

When X1 to X8 are all oxygen groups or all imino groups, expansion and contraction of the negative electrode active material layer 22B during charge and discharge are easily suppressed, and a further advantageous effect can be obtained.

When the first cyclic compound is a cyclic nonmetal complex, the second cyclic compound is a crown ether type metal complex, and the third cyclic compound is an azacrown ether type metal complex, the cyclic compound is more easily expanded and contracted. Therefore, at the time of charge and discharge, the anode active material layer 22B becomes more difficult to expand and contract, so that a better effect can be obtained.

When the negative electrode 22 contains the cyclic compound and one or both of the carbon material and the metal material in a weight ratio of 0.01 to 0.99, expansion and contraction of the negative electrode active material layer 22B during charge and discharge are sufficiently suppressed, and a high battery capacity is obtained, which can provide a further advantageous effect.

Thereby, the process is completed.

In addition, according to the negative electrode 22 used for the cylindrical lithium ion secondary battery, the negative electrode 22 contains the above-described cyclic compound. Therefore, excellent battery characteristics can be obtained for the same reasons as those described for the lithium ion secondary battery.

(2. lithium ion secondary battery and negative electrode for lithium ion secondary battery (laminated film type))

Next, another lithium-ion secondary battery according to an embodiment of the present technology and another negative electrode for a lithium-ion secondary battery according to an embodiment of the present technology will be described. In the following description, the already-described components of the cylindrical lithium-ion secondary battery are sometimes referred to (see fig. 1 and 2).

Fig. 3 shows a three-dimensional structure of another lithium ion secondary battery, and fig. 4 is an enlarged view of a cross-sectional structure of a main portion (wound electrode body 30) of the lithium ion secondary battery along the line IV-IV shown in fig. 3. However, fig. 4 shows a state in which the wound electrode body 30 and the packaging member 40 are separated from each other.

(2-1. constitution)

As shown in fig. 4, the lithium ion secondary battery is, for example, a laminated film type lithium ion secondary battery in which a battery cell (wound electrode body 30) is housed inside a flexible (or flexible) film-like packaging member 40.

The wound electrode body 30 is, for example, a structure in which the cathode 33 and the anode 34 are laminated on each other via the separator 35 and the electrolyte layer 36, and then the cathode 33, the anode 34, the separator 35, and the electrolyte layer 36 are wound. The surface of the wound electrode body 30 is protected by, for example, a protective tape 37. The electrolyte layer 36 is, for example, interposed between the cathode 33 and the separator 35, and between the anode 34 and the separator 35.

The positive electrode 33 is connected to a positive electrode lead 31, and the positive electrode lead 31 is led out from the inside to the outside of the packaging member 40. The positive electrode lead 31 is formed of, for example, the same material as that of the positive electrode lead 25, and the shape of the positive electrode lead 31 is, for example, a thin plate shape, a mesh shape, or the like.

The negative electrode 34 is connected to a negative electrode lead 32, and the negative electrode lead 32 is led out from the inside to the outside of the package member 40. The lead-out direction of the negative electrode lead 32 is the same as the lead-out direction of the positive electrode lead 31, for example. The negative electrode lead 32 is formed of, for example, the same material as the negative electrode lead 26, and the negative electrode lead 32 has, for example, the same shape as the positive electrode lead 31.

[ packaging Member ]

The packing member 40 is, for example, a piece of film that can be folded in the direction of arrow R shown in fig. 3. A part of the packaging member 40 is provided with, for example, a recess 40U for housing the wound electrode body 30.

The packaging member 40 is, for example, a laminate (laminated film) in which a fusion layer, a metal layer, and a surface protection layer are laminated in this order from the inside to the outside. In the manufacturing process of the lithium-ion secondary battery, for example, after the packaging member 40 is folded so that the fusion layers oppose each other via the wound electrode body 30, the outer edge portions of the fusion layers are fused to each other. The fused layer is, for example, a film containing a polymer compound such as polypropylene fibers. The metal layer is, for example, a metal foil containing a metal material such as aluminum. The surface protective layer is, for example, a film containing a polymer compound such as nylon. However, the packing member 40 may include, for example, two laminated films, and the two laminated films may be bonded to each other with, for example, an adhesive.

A close-contact film 41 is inserted between the packaging member 40 and the positive electrode lead 31, for example, to prevent the entry of outside air. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31, and is made of, for example, a polyolefin resin such as polypropylene.

A close-contact film 42 having the same function as the close-contact film 41 is inserted between the exterior member 40 and the negative electrode lead 32, for example. The material for forming the adhesion film 42 is the same as the material for forming the adhesion film 41, except that the adhesion to the negative electrode lead 32 is provided instead of the positive electrode lead 31.

[ Positive electrode, negative electrode and separator ]

The cathode 33 includes, for example, a cathode current collector 33A and a cathode active material layer 33B, and the anode 34 includes, for example, an anode current collector 34A and an anode active material layer 34B. The respective configurations of the cathode current collector 33A, the cathode active material layer 33B, the anode current collector 34A, and the anode active material layer 34B are, for example, the same as those of the cathode current collector 21A, the cathode active material layer 21B, the anode current collector 22A, and the anode active material layer 22B. That is, the negative electrode 34 contains a cyclic compound, more specifically, contains any one or two or more of a first cyclic compound, a second cyclic compound, and a third cyclic compound. The structure of the diaphragm 35 is the same as that of the diaphragm 23, for example.

[ electrolyte layer ]

The electrolyte layer 36 contains a polymer compound together with the electrolytic solution. The electrolyte layer 36 described here is a so-called gel-like electrolyte, and an electrolytic solution is retained in the electrolyte layer 36 by a polymer compound. Thus, a high ionic conductivity (for example, 1mS/cm or more at room temperature) is obtained, and leakage of the electrolyte is prevented. However, the electrolyte layer 36 may also contain other materials such as various additives, for example.

(electrolyte and Polymer Compound)

The electrolyte solution has the same structure as that of the electrolyte solution used for the cylindrical secondary battery. The polymer compound includes, for example, one or both of a homopolymer and a copolymer. Homopolymers are for example polyvinylidene fluoride and the like. The copolymer is, for example, a copolymer of vinylidene fluoride and hexafluoropropylene, or the like.

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 ion conductivity capable of dissociating an electrolyte salt. Therefore, when a polymer compound having ion conductivity is used, the polymer compound is also contained in the solvent.

[ use of electrolyte ]

Instead of the electrolyte layer 36, an electrolyte solution may be used as it is. In this case, the electrolyte is impregnated into the wound electrode body 30 (the cathode 33, the anode 34, and the separator 35).

< 2-2 > actions >

The lithium ion 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 through the electrolyte layer 36. 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 through the electrolyte layer 36.

< 2-3 > method for manufacturing >

The lithium ion secondary battery provided with the electrolyte layer 36 is manufactured, for example, by three steps described below.

[ first step ]

First, the positive electrode 33 is produced through the same steps as those for the positive electrode 21, and the negative electrode 34 is produced through the same steps as those for the negative electrode 22. That is, when the positive electrode 33 is produced, the positive electrode active material layer 33B is formed on both surfaces of the positive electrode current collector 33A, and when the negative electrode 34 is produced, the negative electrode active material layer 34B is formed on both surfaces of the negative electrode current collector 34A.

Next, the electrolytic solution was prepared by the same procedure as the preparation method of the electrolytic solution for the cylindrical secondary battery. Next, the electrolyte solution, the polymer compound, and the organic solvent are mixed to prepare a precursor solution. Next, after the precursor solution is applied to the positive electrode 33, the precursor solution is dried to form the electrolyte layer 36, and after the precursor solution is applied to the negative electrode 34, the precursor solution is dried to form the electrolyte layer 36. Next, the cathode lead 31 is connected to the cathode current collector 33A by welding or the like, and the anode lead 32 is connected to the anode current collector 34A by welding or the like. Next, the cathode 33 and the anode 34 are laminated on each other via the separator 35, and then the cathode 33, the anode 34, and the separator 35 are wound to form the wound electrode body 30. Next, the protective tape 37 is attached to the surface of the wound electrode body 30.

Finally, after the packaging member 40 is folded so as to sandwich the wound electrode assembly 30, the outer edge portions of the packaging member 40 are bonded to each other by a thermal fusion bonding method or the like. In this case, the adhesive film 41 is inserted between the positive electrode lead 31 and the exterior member 40, and the adhesive film 42 is inserted between the negative electrode lead 32 and the exterior member 40. Thereby, the wound electrode assembly 30 is enclosed inside the package member 40, and the lithium-ion secondary battery is completed.

[ second Process ]

First, after the positive electrode 33 and the negative electrode 34 are produced, the positive electrode lead 31 is connected to the positive electrode 33, and the negative electrode lead 32 is connected to the negative electrode 34. Next, after the cathode 33 and the anode 34 are laminated on each other via the separator 35, the cathode 33, the anode 34, and the separator 35 are wound to form a wound body. Next, the protective tape 37 is attached to the surface of the roll. Next, after the wrapping members 40 are folded so as to sandwich the roll, the remaining outer edge portions of the wrapping members 40 are removed and bonded to each other by a heat fusion method or the like, and the roll is stored in the bag-like wrapping member 40.

Next, the electrolyte solution, a monomer as a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor determined as necessary are mixed, and the mixture is stirred to prepare an electrolyte composition. Next, the electrolyte composition is injected into the bag-shaped packaging member 40, and then the packaging member 40 is sealed by a thermal fusion bonding method or the like. Finally, the monomer is thermally polymerized to form a polymer compound. Thereby, the electrolytic solution is held by the polymer compound, and the electrolyte layer 36 is formed. Thus, the wound electrode body 30 is enclosed inside the package member 40, and the lithium-ion secondary battery is completed.

[ third Process ]

First, a roll body is produced through the same process as the second process described above except that the separator 35 having a polymer compound layer formed on a base material layer is used, and then the roll body is stored in the bag-like packaging member 40. Next, after the electrolyte solution is injected into the interior of the packaging member 40, the opening of the packaging member 40 is sealed by a thermal fusion bonding method or the like. Finally, the exterior member 40 is heated while applying a weight to the exterior member 40, and the separator 35 is brought into close contact with the positive electrode 33 and the negative electrode 34, respectively, via the polymer compound layer. Thereby, the polymer compound layer impregnated with the electrolytic solution is gelled, and the electrolyte layer 36 is formed. Thus, the wound electrode body 30 is enclosed inside the package member 40, and the lithium-ion secondary battery is completed.

In the third step, the lithium-ion secondary battery is less likely to swell than in the first step. In the third step, the solvent and the monomer (raw material of the polymer compound) are less likely to remain in the electrolyte layer 36 than in the second step, and the positive electrode 33, the negative electrode 34, and the separator 35 are sufficiently in close contact with the electrolyte layer 36.

Action and Effect (2-4)

According to this laminate film type lithium ion secondary battery, the negative electrode 34 contains a cyclic compound, that is, any one or two or more of the first cyclic compound, the second cyclic compound, and the third cyclic compound. Therefore, excellent battery characteristics can be obtained for the same reasons as described for the cylindrical lithium ion secondary battery.

Other actions and effects for the laminated film type lithium ion secondary battery are the same as those for the cylindrical type lithium ion secondary battery.

Lithium ion secondary battery and use of negative electrode for lithium ion secondary battery

The application of the lithium-ion secondary battery according to one embodiment of the present technology is, for example, the same as described below. However, the use of the negative electrode for a lithium ion secondary battery of the present technology is the same as that of a lithium ion secondary battery, and the use of the negative electrode for a lithium ion secondary battery will be described below.

The lithium ion secondary battery may be used for any purpose, such as a power source for driving a machine, an apparatus, a device, a system (an assembly of a plurality of apparatuses, etc.), and the like, or a power storage source for storing electric power, and is not particularly limited. The lithium ion 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 other power sources. The auxiliary power supply may be, for example, a power supply used instead of the main power supply, or may be a power supply switched from the main power supply as needed. When a lithium ion secondary battery is used as an auxiliary power source, the type of the main power source is not limited to the lithium ion secondary battery.

The lithium ion secondary battery is used, for example, as follows: electronic devices (including portable electronic devices) such as video recorders, digital still cameras, portable telephones, notebook computers, cordless telephones, stereo headphones, portable radios, portable televisions, and portable information terminals; portable life appliances such as electric razors; storage devices such as a standby power supply and a memory card; electric tools such as electric drills and electric saws; a battery pack mounted on a notebook computer or the like as a detachable power supply; medical electronic devices such as pacemakers and hearing aids; electric vehicles such as electric vehicles (including hybrid vehicles); the power storage system is provided for a household battery system or the like which stores power in advance in an emergency. Of course, the lithium ion secondary battery may be used for other applications than the above-described applications.