JP2005093375A - Nonaqueous secondary battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery realizing high capacity by thinning the separator. <P>SOLUTION: The nonaqueous secondary battery contains a wound body of a laminate of a negative electrode, a separator, and a positive electrode, the wound body 1' has a flat part 2 containing a straight separator and a curved part containing a circular arc-like separator and arranged at both ends of the flat part 2; and if the thickness of the separator in the flat part 2 is represented by (a) and the thickness of the separator in a portion most distant from the winding center O of the wound body of the curved part 3 is represented by (b), the thickness (a) is 80% or lower of the thickness (b). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-aqueous secondary battery and a method for manufacturing the same.

  Lithium ion batteries, which are a type of non-aqueous secondary battery, are widely used as a power source for portable devices such as mobile phones and notebook personal computers because of their high energy density. Since the lithium ion battery uses an organic solvent having a lower electrical conductivity than an aqueous electrolyte as an electrolyte, it is difficult to extract a large current. Therefore, in the lithium ion battery, the electrode reaction area is increased by making the electrode structure a winding structure or a laminated structure. If the reaction area of the electrode is increased, the area of the separator must be increased, and the volume occupied by the separator in a limited space also increases. As the separator, for example, a polyolefin-based porous film having a thickness of 10 μm to 30 μm is used (for example, see Patent Document 1).

By the way, in recent years, the increase in capacity of batteries has reached the limit, and in order to further increase the capacity, it is necessary to fill more electrode active materials in a limited space. For this purpose, it is necessary to further reduce the thickness of the separator.
JP 2002-100410 A

  However, the thinner the separator is, the more difficult it is to produce a non-aqueous secondary battery. In particular, when the wound body is manufactured, since the separator is tightly wound, tension is applied to the separator. However, when the thickness of the separator is reduced, the separator may be stretched or cut due to insufficient tensile strength. It is not easy to manage the process so that the separator does not stretch or cut.

  The non-aqueous secondary battery of the present invention is a non-aqueous secondary battery including a wound body of a laminate in which a negative electrode, a separator, and a positive electrode are laminated, and the wound body includes the linear separator. A flat portion and a curved portion including the arc-shaped separator and disposed at both ends of the flat portion, the thickness of the separator in the flat portion being a, and winding of a wound body of the curved portion The thickness a is 80% or less of the thickness b, where b is the thickness of the separator at the position farthest from the center.

The method for producing a non-aqueous secondary battery of the present invention comprises: (a) preparing a positive electrode, a porous material, and a negative electrode; and the positive electrode so that the porous material is disposed between the positive electrode and the negative electrode And a step of stacking the porous material and the negative electrode to form a laminate, (b) a step of storing the laminate in a container and injecting an organic solvent into the container, and (c) the laminate Pressurizing the body while heating at a predetermined temperature to reduce the thickness of the laminate, and in the step (a), as the porous material, a semi-compatible or compatible polymer blend, and An inorganic material dispersed in a polymer blend, wherein the polymer blend has a first polymer having a solubility in the organic solvent at the predetermined temperature of 0.1 g / cm ³ or more, and the solubility is 0.1 g / cm. ^A second polymer of less than ³ In the step (c), the laminate is pressurized while eluting a part of the first polymer in the porous material into the organic solvent.

Another method for producing the non-aqueous secondary battery of the present invention is as follows: (a) preparing a positive electrode, a porous material, and a negative electrode, and placing the porous material between the positive electrode and the negative electrode, Including the step of stacking the positive electrode, the porous material, and the negative electrode to form a laminate, and (b) pressurizing the laminate while heating to reduce the thickness of the laminate, In the step (a), the porous material includes a semi-compatible or compatible polymer blend and an inorganic material dispersed in the polymer blend, and the polymer blend has a first melting point of T _m1 ° C. A material containing a polymer and a second polymer having a melting point of T _m2 ° C is prepared (however, T _m1 and T _m2 satisfy the relationship of T _m1 <T _m2 ), and the step (b) in, the laminate was heated at T _m1 ° C. or more T _m2 of less than ° C. temperature, While a portion of the first polymer in serial within the porous material eluted on the surface of the porous material, characterized in that pressurizing the laminate.

  According to the present invention, it is possible to provide a non-aqueous secondary battery with an increased capacity.

(Embodiment 1)
The nonaqueous secondary battery and the manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to FIGS. 1A to 1E and FIGS. 2A to 2C.

  As shown in FIGS. 1A and 1B, in the method for manufacturing a nonaqueous secondary battery according to the present embodiment, first, a positive electrode 4, a porous material 6, and a negative electrode 5 are prepared. The positive electrode 4, the negative electrode 5, and the porous material 6 are stacked so that the porous material 6 is disposed therebetween to form a band-shaped laminate, and the band-shaped laminate is wound to produce the wound body 1. To do. In FIG. 1B, 4a is a positive terminal lead and 5b is a negative terminal lead.

  Next, as shown in FIG. 1C, the wound body 1 is housed in the container 8, and after injecting an organic solvent into the container 8, the opening of the container 8 is sealed. In FIG. 1D, the wound body 1 of the laminated body is housed in the container 8, but instead of the wound body 1, a plurality of rectangular positive electrodes, porous materials, and negative electrodes are included. For example, a laminate in which the positive electrode, the porous material, the negative electrode, the porous material, the positive electrode,...

  Next, as shown in FIG. 1D, the wound body 1 is sandwiched between two metal plates 9 and heated at a predetermined temperature while being pressed in a direction in which the positive electrode and the negative electrode are brought closer to each other. Is made thinner (see FIG. 1E). As a means for heating the wound body 1, there are a method in which the wound body 1 is disposed in a high-temperature tank, or is immersed in a water bath or an oil bath. In FIG. 1E, 1 ′ denotes a wound body after heating and pressurization, that is, a thin wound body.

As shown in FIG. 1A, the porous material 6 includes a semi-compatible or compatible polymer blend 11 and an inorganic material 10 dispersed in the polymer blend 11, and the polymer blend 11 has a predetermined organic at a predetermined temperature. A first polymer having a solubility in a solvent of 0.1 g / cm ³ or more and a second polymer having the solubility of less than 0.1 g / cm ³ are included. Therefore, as shown in FIG. 1D, when the wound body 1 is heated to a predetermined temperature, for example, 80 ° C. to 150 ° C. while being pressurized at a predetermined pressure, for example, 3 kPa to 700 kPa, The first polymer elutes into the organic solvent, and a part of the eluted first polymer 12 penetrates into the positive electrode 4 and the negative electrode 5 (see FIG. 2C).

  On the other hand, the voids in the porous material 6 generated by the elution of a part of the first polymer are crushed by being pressurized, but the porous state of the porous material is at least by the second polymer and the inorganic material 10. Is retained, so that the movement of ions between the positive electrode and the negative electrode is ensured. The inorganic material 10 plays the role of a pillar and suppresses the porous material 6 from becoming too thin due to pressurization.

  Thus, according to the manufacturing method of the nonaqueous secondary battery of the present embodiment, a part of the first polymer is eluted while a part of the first polymer contained in the porous material 6 is eluted. As shown in FIG. 2C, the voids in the porous material generated by the crushing of the porous material after heating and pressurization, that is, the thickness a of the separator 7 before the heating and pressurizing are applied. It can be made thinner than the thickness of the porous material 6 (see FIG. 1A).

  As described above, since the thickness of the wound body 1 can be reduced by reducing the thickness of the separator, it is possible to fill more active material in the battery outer casing, and increase the capacity of the non-aqueous secondary battery. Can be realized.

The upper limit of the solubility of the first polymer is not particularly limited, but is usually 1 g / cm ³ or less, and the lower limit of the solubility of the second polymer is not particularly limited, but is usually 0.0001 g / cm ^3. That's it.

  Moreover, in the manufacturing method of the non-aqueous secondary battery according to the present embodiment, for example, the porous material 6 having a thickness of about 10 μm to 50 μm is used as a separator material, and the wound body 1 is heated and pressurized to obtain the porous material. Since the thickness of 6 is reduced to, for example, 80% or less, it is possible to suppress elongation, cutting, and the like due to insufficient tensile strength of the separator, rather than handling a thinly processed separator in advance. Therefore, a high capacity non-aqueous secondary battery can be easily manufactured without any difficulty in the manufacturing process.

  As described above, according to the method for manufacturing a non-aqueous secondary battery of the present embodiment, a high-capacity non-secondary battery can be easily manufactured.

  In the present specification, “solubility” is a value measured according to the following method. The polymer 0.1 g and the organic solvent 5 ml were put in a reagent bottle, the reagent bottle was sealed, the polymer was heated at a predetermined temperature for 30 minutes, and then left for 1 hour. Thereafter, the solution portion was removed by decantation, the solvent was removed from the residue by vacuum drying, the weight of the polymer not dissolved in the organic solvent was determined, and the weight of the dissolved polymer was calculated. When the organic solvent is an electrolyte solution of a non-aqueous secondary battery containing an electrolyte salt, after adding a large amount of water to the residue, the agglomerated polymer is taken out, and then the organic solvent is vacuum-dried in the same manner as described above. The weight of the polymer not dissolved in the solution was determined, and the weight of the dissolved polymer was calculated.

Examples of the first polymer contained in the porous material 6 include a polyethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ionomer resin, and a vinylidene fluoride-hexafluoropropylene copolymer (P (VDF-HFP). At least one resin selected from the group consisting of: Since the solubility in an organic solvent described later at 80 ° C. to 150 ° C. is 0.1 g / cm ³ or more, if it is heated to 80 ° C. to 150 ° C. in an organic solvent, it can be easily eluted in the organic solvent. is there.

  As the second polymer contained in the porous material 6, it is preferable to use at least one resin selected from the group consisting of polysulfone, polycarbonate, and a styrene-methyl methacrylate copolymer. This is because the solubility is smaller than that of the first polymer, the heat resistance is excellent, and the strength is high. Further, the second polymer may have a crosslinked structure in order to further reduce the solubility or improve the heat resistance.

  The porosity of the porous material 6 is preferably 20 to 80%. If the porosity of the porous material 6 is too small, the wound body 1 cannot be sufficiently thinned by heating and pressurizing the wound body 1. If the porosity of the porous material 6 is too large, the wound body This is because problems such as elongation and cutting due to insufficient tensile strength are likely to occur in the porous material 6 at the time of production, and advanced process management is required.

As the inorganic material contained in the porous material 6, for example, at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , TiO ₂ , montmorillonite, and BaTiO ₂ can be used. Although there is no restriction | limiting in particular about the average particle diameter of an inorganic material, a 0.1 to 5 micrometer thing is suitable.

  The porous material 6 preferably further contains a compatibility improver in order to improve the compatibility between the polymers and increase the strength of the porous material 6. As the compatibility improver, for example, terpene resin, aromatic resin, dicyclopentadiene resin, wax having a saturated hydrocarbon group, or the like can be used.

  The porous material 6 can be produced, for example, by the following method. First, two or more polymers having different solubilities in a predetermined organic solvent, inorganic fine particles (inorganic material), and a solvent for reducing the viscosity of the polymer, for example, tetrahydrofuran (THF) are mixed, and all polymers are mixed. Is stirred until it is uniformly dissolved to form a slurry. Next, an inorganic salt or a hydrophilic high-boiling compound is added to the obtained slurry and stirred, and then the uniform slurry is formed into a film. Next, after removing the solvent (THF) from the obtained film, the inorganic salt or hydrophilic high boiling point compound is removed by water washing to make the film porous. Examples of inorganic salts include LiBr and LiCl, and examples of hydrophilic high-boiling compounds include N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO).

  Since the porous material produced by the above method is produced without going through a stretching process, for example, even when heated to 80 ° C. to 150 ° C., the degree of shrinkage due to stress relaxation is small. Therefore, if the porous material produced by the above method is used, a non-aqueous secondary battery excellent in safety can be manufactured even at a high temperature.

  As the container 8 for storing the wound body 1 (laminated body) (see FIG. 1C), for example, a container formed of a flexible film can be used. The film contains a material capable of sealing the opening of the container 8 by heat welding or the like after the wound body 1 (laminated body) is contained in the container, for example, a polyolefin such as polyethylene or polypropylene. Is preferred.

  Examples of the organic solvent injected into the container 8 include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propionate, ethylene carbonate, propylene carbonate (PC), butylene carbonate, gamma-butyrolactone, ethylene glycol sulfite, 2-dimethoxyethane, 1,3-dioxolane, tetrahydrofuran, 2-methyl-tetrahydrofuran, diethyl ether and the like can be used.

The organic solvent injected into the container 8 may be an electrolyte solution for a non-aqueous secondary battery. As an electrolytic solution, for example, the above-mentioned organic _{solvent, LiClO 4, LiPF 6, LiBF} 4, LiAsF 6, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li 2 C 2 F 4 (SO 3) 2, LiN Inorganic ion salts such as (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiCnF _{2n + 1} SO ₃ (n ≧ 2), LiN (RfOSO ₂ ) ₂ [where Rf is a fluoroalkyl group] Those prepared by dissolving can be used. The concentration of the electrolyte solution of an inorganic ion ^{salt, 0.5mol / dm 3 ~1.5mol / dm} 3, in particular 0.9mol / dm ³ ~1.25mol / dm ³ preferred.

  Moreover, in the manufacturing method of the nonaqueous secondary battery of this Embodiment, after the process (refer FIG. 1C) which accommodates the winding body 1 (laminated body) in the container 8, and inject | pours electrolyte solution in the container 8. It is preferable to perform chemical conversion (preliminary charging) before the step of reducing the thickness of the wound body 1 by applying pressure while heating the wound body 1 (porous material) (see FIG. 1D). If chemical conversion (preliminary charging) is performed before the step of reducing the thickness of the wound body 1 (see FIG. 1D), gas generated during chemical conversion (preliminary charging) can be easily extracted from the electrode.

  In addition, after the step of reducing the thickness of the wound body 1 by applying pressure while heating the wound body 1 (see FIG. 1D), the wound body 1 ′ (see FIG. 1E) thinned from the container 8 is used. The wound body 1 ′ may be taken out and replaced with a predetermined metal can or the like, or the container 8 may be used as a battery outer container.

The positive electrode 4 and the negative electrode 5 used in the manufacturing method of the nonaqueous secondary battery of the present embodiment are not particularly limited and can be manufactured by a conventionally known method. (See Figure 1A)
The positive electrode 4 is obtained by, for example, applying a positive electrode mixture paste obtained by adding an appropriate solvent to a positive electrode material (positive electrode active material, conductive additive, binder, etc.) and sufficiently kneading the mixture to a current collector, And a positive electrode mixture layer controlled to a predetermined electrode density.

  As the current collector of the positive electrode 4, for example, an aluminum foil, a punching metal, a mesh, an expanded metal, or the like can be used, but an aluminum foil is usually used. The thickness of the current collector of the positive electrode is preferably 10 μm or more and 30 μm or less. This is because generation of wrinkles at the time of applying the positive electrode mixture-containing paste and breakage due to tension at the time of winding and the like are less likely to occur, and a thin and highly reliable positive electrode can be manufactured.

  The positive electrode terminal lead 4a can be formed by leaving a portion (exposed portion) where the positive electrode mixture layer is not formed on the current collector (for example, aluminum foil) at the time of producing the positive electrode, and using the exposed portion as the positive electrode terminal lead 4a. The positive electrode terminal lead 4a is not necessarily formed integrally with the current collector, and may be provided by bonding an aluminum foil or the like to the current collector later.

  Similarly to the positive electrode 4 for the negative electrode 5, a negative electrode mixture paste obtained by adding a suitable solvent to the negative electrode material (negative electrode active material, conductive additive, binder) and sufficiently kneading was applied to the current collector, It can be produced by forming a negative electrode mixture layer controlled to have a predetermined thickness and a predetermined electrode density.

  As the current collector of the negative electrode 5, for example, a copper foil, a punching metal, a mesh, an expanded metal, or the like can be used, and a copper foil is usually used. The thickness of the current collector of the positive electrode is preferably 5 μm or more and 30 μm or less. This is because a thin negative electrode having a high reliability can be produced because the occurrence of wrinkles at the time of applying the negative electrode mixture-containing paste and the occurrence of tearing due to the pulling at the time of winding and the like are few.

  The negative electrode terminal lead 5a can be formed by leaving a portion (exposed portion) where the positive electrode mixture layer is not formed on the current collector (for example, copper foil) and forming the exposed portion as the negative electrode terminal lead 5a. The negative electrode terminal lead 5a is not necessarily formed integrally with the current collector, and may be provided by bonding a copper foil or the like to the current collector later.

  FIG. 2A shows a cross-sectional view of a wound body 1 ′ of a non-aqueous secondary battery manufactured by the method for manufacturing a non-aqueous secondary battery of the present embodiment, and FIGS. 2B and 2C show the wound body 1 ′. A partially enlarged view is shown.

  The wound body 1 ′ includes a flat portion 2 including a linear laminated body, and includes curved portions disposed at both ends of the flat portion 2 including a curved laminated body, and the thickness of the separator in the flat portion 2 is set to a. When the thickness of the separator in the portion of the curved portion 3 farthest from the winding center of the winding body is b, the thickness a is 10% or more and 80% or less of the thickness b.

  The flat portion 2 is a portion pressed by the metal plate 9 in the step described with reference to FIG. 1D. In the flat portion 2, as shown in FIG. 2C, the first portion eluted from the porous material 6 (see FIG. 1A). A part of one polymer 12 penetrates into the positive electrode 4 and the negative electrode 5. In FIG. 2C, 7 is a porous material that is thinned by pressurization, that is, a separator, 11 is a polymer blend containing a first polymer and a second polymer, 10 is an inorganic material, and 11a is a separator 7. The holes 4 are positive electrodes, and 5 is a negative electrode.

  On the other hand, since the porous material in the place farthest from the winding center O of the wound body is not pressurized in the process described with reference to FIG. 1D, the wound body 1 ′ in the curved portion 3 is wound. In a place farthest from the center O, as shown in FIG. 2B, the thickness b of the separator 7 is equal to the thickness of the porous material 6 (see FIG. 1A) before being heated and pressurized. In FIG. 2B, 11 is a polymer blend containing the first polymer and the second polymer, 10 is an inorganic material, 11a is a hole, 4 is a positive electrode, and 5 is a negative electrode.

As shown in FIGS. 2B and 2C, the separator 7 includes a semi-compatible or compatible polymer blend 11 and an inorganic material 10 dispersed in the polymer blend 11. The polymer blend 11 has a predetermined temperature at a predetermined temperature. A first polymer having a solubility in an organic solvent of 0.1 g / cm ³ or more and a second polymer having a solubility of less than 0.1 g / cm ³ . The said predetermined temperature is 80 degreeC or more and 150 degrees C or less, for example, and the said organic solvent is the electrolyte solution of a non-aqueous secondary battery, for example.

The first polymer is, for example, at least one resin selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ionomer resin, and a vinylidene fluoride-hexafluoropropylene copolymer. The second polymer is, for example, at least one resin selected from the group consisting of polysulfone, polycarbonate, and styrene-methyl methacrylate copolymer, and the inorganic material is SiO ₂ , Al ₂ O ₃ , TiO ₂ , It is at least one selected from the group consisting of montmorillonite and BaTiO ₂ .

(Embodiment 2)
A nonaqueous secondary battery and a manufacturing method thereof according to Embodiment 2 of the present invention will be described with reference to FIGS. 3A to 3E and FIGS. 2A to 2C.

  As shown in FIGS. 3A and 3B, in the method for manufacturing a non-aqueous secondary battery according to the present embodiment, first, positive electrode 4, porous material 6, and negative electrode 5 are prepared. The positive electrode 4, the negative electrode 5, and the porous material 6 are stacked so that the porous material 6 is disposed therebetween to form a belt-like laminate, and the belt-like laminate is wound to produce the wound body 1. To do. In FIG. 3B, 4a is a positive terminal lead and 5b is a negative terminal lead.

  Next, as shown in FIG. 3C, the wound body 1 is sandwiched between two metal plates 9 and heated at a predetermined temperature and pressurized at a predetermined pressure to reduce the thickness of the wound body 1. Then, the wound body 1 ′ is produced (see FIG. 3D). As a means for heating the wound body 1, there are a method in which the wound body 1 is disposed in a high-temperature tank, or is immersed in a water bath or an oil bath.

  Next, as shown in FIG. 3D, the wound body 1 ′ is housed in the container 8, and after the electrolyte is injected into the container 8, the opening of the container 8 is sealed. In FIG. 3C, the wound body 1 is pressurized, but instead of the wound body 1, a plurality of rectangular positive electrodes, porous materials, and negative electrodes are included. You may pressurize the laminated body laminated | stacked in order of material, a negative electrode, positive electrode ....

As shown in FIG. 3A, the porous material 6 includes a semi-compatible or compatible polymer blend 11 and an inorganic material 10 dispersed in the polymer blend 11, and the polymer blend 11 has a melting point of T _m1 ° C. 1 polymer and a second polymer having a melting point of T _m2 ° C. However, T _m1 and T _m2 satisfy the relationship of T _m1 <T _m2 . Therefore, as shown in FIG. 3C, when the wound body 1 is heated at a temperature of T _m1 ° C or higher and lower than T _m2 ° C while being pressurized at a predetermined pressure, for example, 3 kPa or higher and 700 kPa or lower, The first polymer is eluted on the surface of the porous material 6, and a part of the eluted first polymer 12 penetrates into the positive electrode 4 and the negative electrode 5 (see FIG. 2C). In addition, it is preferable that heating temperature is 200 degrees C or less. This is because the polymer constituting the separator and the binder used for the electrode may be partially decomposed to cause deterioration of battery performance.

  On the other hand, the voids in the porous material 6 caused by the dissolution of a part of the first polymer are crushed by being pressurized, but the porous material 6 is porous by at least the second polymer and the inorganic material 10. The state is maintained, and movement of ions between the positive electrode and the negative electrode is ensured. The inorganic material 10 plays the role of a pillar and suppresses the porous material 6 from becoming too thin due to pressurization.

  Thus, according to the manufacturing method of the nonaqueous secondary battery of the present embodiment, by eluting part of the first polymer while eluting part of the first polymer contained in the porous material, Since the generated voids in the porous material are crushed by a heating press, the thickness of the porous material after heating and pressing, that is, the thickness a of the separator 7 (see FIG. 2C) is set to the porous material 6 before being heated and pressed. It can be made thinner than the thickness (see FIG. 1A).

  As described above, since the thickness of the wound body 1 can be reduced by reducing the thickness of the separator, it is possible to fill more active material in the battery outer casing, and increase the capacity of the non-aqueous secondary battery. Can be realized.

  Moreover, in the manufacturing method of the nonaqueous secondary battery according to the present embodiment, for example, the porous material 6 having a thickness of about 10 μm to 50 μm is used as the separator material, and the wound body is heated and pressurized, and the porous material 6 is used. For example, since the thickness is reduced to 80% or less, it is possible to suppress elongation, cutting, or the like due to insufficient tensile strength of the separator in the manufacturing process, compared to the case of handling a thinly processed separator in advance. Therefore, a high capacity non-aqueous secondary battery can be easily manufactured without any difficulty in the manufacturing process.

  As described above, according to the method for manufacturing a non-aqueous secondary battery of the present embodiment, a high-capacity non-secondary battery can be easily manufactured.

  In the present specification, the “melting point” is a value measured with a differential scanning calorimeter (DSC).

The manufacturing method of the non-aqueous secondary battery of the present embodiment includes (1) heating and pressurizing the wound body that does not absorb the organic solvent, and (2) a first melting point of T _m1 ° C. And a porous material 6 including a semi-compatible or compatible polymer blend 11 including a second polymer having a melting point of T _m2 ° C and an inorganic material 10 dispersed in the polymer blend 11 (see FIG. 3A), and the method of manufacturing the nonaqueous secondary battery of Embodiment 1 except that the laminate including the positive electrode 4, the porous material 6, and the negative electrode 5 is heated at a temperature of _Tm1 ° C or higher and _lower than _Tm2 ° C. It is the same. As the positive electrode 4, the negative electrode 5, the outer container 8, and the electrolytic solution, the same ones as in the method of manufacturing the nonaqueous secondary battery of the first embodiment can be used, and the porous material 6 is also the first embodiment. The same non-aqueous secondary battery manufacturing method can be used. That is, the melting point of the first polymer having a solubility in an organic solvent at a predetermined temperature of 0.1 g / cm ³ or more is T _m1 ° C, and the melting point of the second polymer having a solubility of less than 0.1 g / cm ³ is T _m2 ° C.

  In the method for manufacturing a non-aqueous secondary battery according to the present embodiment, chemical conversion (preliminary charging) may be performed after the wound body 1 is thinned by heating and pressurizing. Moreover, in the manufacturing method of the nonaqueous secondary battery of this Embodiment demonstrated using FIG. 3A-FIG. 3E, before winding the wound body 1 in the container 8, it heats and pressurizes, However, It restrict | limits to this Instead, the wound body 1 may be heated and pressurized after the wound body 1 is stored in the container 8 and before the electrolytic solution is injected into the container 8.

  FIG. 2A shows a cross-sectional view of a wound body 1 ′ of a non-aqueous secondary battery manufactured by the method for manufacturing a non-aqueous secondary battery of the present embodiment, and FIGS. 2B and 2C show the wound body 1 ′. A partially enlarged view is shown. The wound body 1 ′ includes a flat portion 2 including a linear laminated body, and includes curved portions disposed at both ends of the flat portion 2 including a curved laminated body, and the thickness of the separator in the flat portion 2 is set to a. When the thickness of the separator in the portion of the curved portion 3 farthest from the winding center of the winding body is b, the thickness a is 10% or more and 80% or less of the thickness b.

  The flat portion 2 is a portion pressed by the metal plate 9 in the step described with reference to FIG. 3C. In the flat portion 2, as shown in FIG. 2C, the first portion eluted from the porous material 6 (see FIG. 1A). A part of one polymer 12 penetrates into the positive electrode 4 and the negative electrode 5. In FIG. 2C, 7 is a porous material that is thinned by pressurization, that is, a separator, 11 is a polymer blend containing a first polymer and a second polymer, 10 is an inorganic material, and 11a is a separator 7. The holes 4 are positive electrodes, and 5 is a negative electrode.

  On the other hand, since the porous material in the place farthest from the winding center O of the wound body 1 ′ is not pressurized in the process described with reference to FIG. In a place farthest from the winding center O, as shown in FIG. 2B, the thickness b of the separator 7 is equal to the thickness of the porous material 6 (see FIG. 1A) before being heated and pressurized. In FIG. 2B, 11 is a polymer blend containing the first polymer and the second polymer, 10 is an inorganic material, 11a is a hole, 4 is a positive electrode, and 5 is a negative electrode.

As shown in FIGS. 2B and 2C, the separator 7 includes a semi-compatible or compatible polymer blend 11 and an inorganic material 10 dispersed in the polymer blend 11. The polymer blend 11 has a melting point of T _m1 ° C. And a second polymer having a melting point of T _m2 ° C. However, T _m1 and T _m2 satisfy the relationship of T _m1 <T _m2 .

The first polymer is, for example, at least one resin selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ionomer resin, and a vinylidene fluoride-hexafluoropropylene copolymer. The second polymer is, for example, polysulfone, and the inorganic material is at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , TiO ₂ , montmorillonite, and BaTiO ₂ .

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In addition, the thickness of a wound body is the value measured by the following method.

[Thickness of wound body]
Using a dial thickness gauge (measuring element diameter: 6 mm, minimum scale: 0.1 μm), the thickness of the wound body was measured at six points, and the average value was taken as the thickness of the wound body.

(Example 1)
[Production of porous material]
In a container, 0.9 g of ethylene-vinyl acetate copolymer (Scientific Polymer Products, vinyl acetate 50%, melting point T _m1 = 140 ° C.) and compatibilizer (ExxonMobile Chemical, “Escorez2596”, melting point T _m2 = 80 ° C.) 0.36 g, polysulfone (manufactured by BASF, “Ultrason S6010”, melting point 220 ° C.) 3.96 g, SiO ₂ powder (Aldrich, fumed silica, average particle size 1 μm, surface area 255 m ² / g) 1.2 g and 33 g of THF were mixed and the mixture was stirred at room temperature until all the polymer was uniformly dissolved. After adding 7 g of NMP / PC (weight ratio 5: 2) to the resulting slurry and stirring for 1 hour, the uniform slurry was cast on a PET film, and THF was removed from the resulting film at room temperature. did. Thereafter, the film was immediately immersed in water to remove NMP / PC from the film to obtain a porous material (thickness 25 μm, porosity 50%).

The solubility of the ethylene-vinyl acetate copolymer in the electrolytic solution at 90 ° C. is 0.2 g / cm ³ , and the solubility of polysulfone in the electrolytic solution at 90 ° C. is 0.001 g / cm ³ . In the electrolyte solution, a solution in which LiPF ₆ is dissolved in a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1: 2) to a concentration of 1.2 mol / dm ³ is used. Using.

[Production of positive electrode]
92 parts by weight of LiCoO ₂ as a positive electrode active material, 5 parts by weight of acetylene black as a conductive auxiliary agent, and 3 parts by weight of polyvinylidene fluoride as a binder are mixed in NMP (solvent) so as to be uniform. An agent-containing paste was prepared. The paste was applied on both sides of a 15 μm thick aluminum foil serving as a current collector (active material coating length on the front surface 281 mm, active material coating length on the back surface 212 mm) and dried to form a positive electrode mixture layer, and then a calendar Processing was performed to adjust the thickness of the positive electrode mixture layer so that the total thickness was 150 μm. Then, it cut | disconnected to width 43mm and length 320mm, and produced the positive electrode. A tab made of aluminum foil was attached as the positive electrode terminal lead 4a to the exposed portion of the aluminum foil (the portion where the positive electrode mixture layer was not formed).

[Production of negative electrode]
A negative electrode mixture-containing paste was prepared by mixing 95 parts by weight of graphite as a negative electrode active material and 5 parts by weight of polyvinylidene fluoride as a binder so as to be uniform in NMP (solvent). The paste was applied to both sides of a 10 μm thick copper foil serving as a current collector (active material coating length on the surface 287 mm, active material coating length on the back surface 228 mm) and dried to form a negative electrode mixture layer. Calendar treatment was performed to adjust the thickness of the negative electrode mixture layer so that the total thickness was 142 μm. Then, it cut | disconnected to width 45mm and length 300mm, and produced the negative electrode. A tab made of nickel foil was attached as the negative electrode terminal lead 5a to the exposed portion of the copper foil (the portion where the negative electrode mixture layer was not formed).

  Next, as shown in FIG. 1A, the positive electrode 4, the porous material 6, and the negative electrode 5 are stacked to form a laminate so that the porous material 6 is disposed between the positive electrode 4 and the negative electrode 5. Thus, a wound body 1 having a structure in which 20 layers each of the positive electrode 4 and the negative electrode 5 were laminated was produced. The thickness W of the wound body 1 at this time was 3.1 mm (see FIG. 1B).

Next, the wound body 1 is put in a container 8 made using a laminate film having a three-layer structure made of polyester-aluminum-modified polyolefin, and then ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume). After pouring 5 ml of an electrolytic solution in which LiPF ₆ was dissolved in a mixed solvent of a ratio 1: 2) so that the concentration was 1.2 mol / dm ³ , the container 8 was vacuum-sealed and left overnight. . Thereafter, chemical conversion (preliminary charging) was performed until the voltage reached 3.9 V, the container 8 was once opened and degassed, then resealed and discharged to 3.0 V.

  Subsequently, as shown in FIG. 1D, the wound body 1 is held at 90 ° C. for 15 minutes while pressing the container 8 containing the wound body 1 and the electrolyte between the two metal plates 9. Put in. Furthermore, the container 8 in which the wound body 1 and the electrolytic solution are stored is left in a thermostat bath at 90 ° C. for 30 minutes while being pressurized at 10 kPa, and then is taken out from the thermostat bath and sandwiched between the metal plates 9. And cooled to room temperature.

  Next, when wound body 1 '(refer FIG. 1B) was taken out from the container 8, and the thickness of wound body 1' which absorbed electrolyte solution was measured, it was 2.61 mm. Since the thickness (2.61 mm) of the wound body 1 ′ measured in the state of absorbing the electrolytic solution is thinner than the thickness W (3.1 mm) of the wound body 1 before heating and pressurization, It can be seen that the body 1 is thinned by being heated and pressurized. In the flat portion 2 (see FIG. 2A) of the wound body 1 ′, the positive electrode 4 and the negative electrode 5 and the separator 7 were joined by the ethylene-vinyl acetate copolymer (first polymer 12).

(Example 2)
In the same manner as in Example 1, a positive electrode, a negative electrode, and a porous material were produced, and a wound body 1 was produced. The thickness W of the wound body 1 at this time was 3.1 mm (see FIG. 1B).

  Next, the wound body 1 is put in a container 8 made using a laminate film having a three-layer structure made of polyester-aluminum-modified polyolefin, and then 5 ml of dimethyl carbonate is injected into the container 8. 8 was vacuum sealed and left overnight. Subsequently, as shown in FIG. 1D, while holding the container 8 containing the wound body 1 and dimethyl carbonate between two metal plates 9 and pressurizing, the wound body 1 is kept at a constant temperature bath at 90 ° C. for 15 minutes. Put in. Furthermore, the container 8 containing the wound body 1 and dimethyl carbonate was left in a thermostat at 90 ° C. for 30 minutes while being pressurized at 5 kPa, and then removed from the thermostat and sandwiched between the metal plates 9. It cooled until it became room temperature in the state.

The solubility of the ethylene-vinyl acetate copolymer in dimethyl carbonate at 90 ° C. is 0.5 g / cm ³ , and the solubility of polysulfone in dimethyl carbonate at 90 ° C. is 0.0008 g / cm ³ .

  Next, when wound body 1 '(refer FIG. 1E) was taken out from the container 8, and thickness of wound body 1' which absorbed dimethyl carbonate was measured, it was 2.61 mm. Since the thickness (2.61 mm) of the wound body 1 ′ measured in a state in which dimethyl carbonate is absorbed is thinner than the thickness W (3.1 mm) of the wound body 1 before heating and pressurization. It can be seen that the body 1 is thinned by being heated and pressurized. In the flat portion 2 (see FIG. 1A) of the wound body 1 ′, the positive electrode 4 and the negative electrode 5 and the separator 7 were joined by an ethylene-vinyl acetate copolymer.

Next, after putting wound body 1 'into a vacuum dryer and removing most dimethyl carbonate from wound body 1', winding body 1 'is made into the three-layer structure which consists of polyester-aluminum-modified polyolefin. It puts in the container 8 produced using the laminate film, and then the concentration is 1.2 mol / dm ^{3 in} a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1: 2). After injecting 5 ml of an electrolyte solution in which LiPF ₆ was dissolved into the container 8, the container 8 was vacuum-sealed and left overnight. Thereafter, preliminary charging (initial charging) was performed until the voltage became 3.9 V, the container 8 was once opened and degassed, and then the container 8 was resealed and discharged to 3.0 V.

(Example 3)
In the same manner as in Example 1, a positive electrode, a negative electrode, and a porous material were produced, and a wound body 1 was produced. The thickness W of the wound body 1 at this time was 3.1 mm (see FIG. 3B). Next, as shown in FIG. 3C, the wound body 1 was placed in a thermostatic bath at 165 ° C. for 5 minutes while pressing the wound body 1 between the two metal plates 9. Further, the wound body 1 was left in a thermostatic bath at 165 ° C. for 3 hours while being pressurized at 100 kPa, then taken out from the thermostatic bath and cooled to room temperature while being sandwiched between the metal plates 9. The thickness of the wound body 1 ′ (see FIG. 3D) was 2.67 mm, which was thinner than the thickness W (3.1 mm). In the flat portion 2 (see FIG. 1A) of the wound body 1 ′, the positive electrode 4 and the negative electrode 5 and the separator 7 were joined by an ethylene-vinyl acetate copolymer.

Next, the wound body 1 ′ is put in a container 8 made using a laminate film having a three-layer structure made of polyester-aluminum-modified polyolefin, and then ethylene carbonate (EC) and methyl ethyl carbonate (EMC) ( After injecting 5 ml of an electrolyte solution in which LiPF ₆ was dissolved in a mixed solvent having a volume ratio of 1: 2) to a concentration of 1.2 mol / L into the container 8, the container 8 was vacuum-sealed and left overnight. did. Next, chemical conversion (preliminary charging) was performed until the voltage reached 3.9 V, the container 8 was once opened and degassed, then resealed and discharged to 3.0 V.

(Comparative Example 1)
A wound body 1 was produced in the same manner as in Example 1 except that a PE separator (Asahi Kasei Co., Ltd., “N9420”, thickness 20 μm) was used instead of the porous material produced in Example 1. The thickness W of the wound body 1 at this time was 2.95 mm (see FIG. 1B).

This wound body 1 is put in a container 8 made using a laminate film having a three-layer structure made of polyester-aluminum-modified polyolefin, and then ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1 : 5 ml of an electrolyte solution in which LiPF ₆ was dissolved in the mixed solvent of 2) so as to have a concentration of 1.2 mol / dm ³ was poured into the container 8, and then the container 8 was vacuum-sealed and left overnight. Next, chemical conversion (preliminary charging) was performed until the voltage became 3.9 V, and after the container 8 was opened and degassed, the container 8 was resealed and discharged to 3.0 V.

  Next, as shown in FIG. 1D, while holding the container 8 containing the wound body 1 and the electrolytic solution between two metal plates 9 and pressurizing the wound body 1, a constant temperature bath at 90 ° C. for 15 minutes. Put in. Further, the container 8 containing the wound body 1 and the electrolytic solution was left in a thermostat bath at 90 ° C. for 30 minutes while being pressurized at 10 kPa, and then taken out from the thermostat bath and sandwiched between the metal plates 9. It cooled until it became room temperature in the state. Next, the wound body 1 ′ was taken out from the container 8, and the thickness of the wound body 1 ′ in a state in which the electrolytic solution was absorbed was measured and found to be 3.03 mm.

  Regarding the non-aqueous secondary batteries of Examples 1 to 3 and Comparative Example 1, the thickness a of the separator in the flat portion 2 (see FIG. 2C) and the winding of the winding body in the curved portion 3 are as follows. The thickness b of the separator at the place farthest from the rotation center O was measured (see FIG. 2B), and the results are shown in Table 1.

[Separator thickness]
After removing the wound body from the non-aqueous secondary battery and washing the wound body with dimethyl carbonate, dimethyl carbonate was removed from the wound body under reduced pressure. The wound body thus cleaned was subjected to freezing macrotome processing, and then cut into round pieces, and the cross section of the wound body was observed with a scanning electron microscope to measure the thickness a and thickness b of the separator.

In addition, the nonaqueous secondary batteries of Examples 1 to 3 and Comparative Example 1 were charged to 4.2 V, then discharged to 0.2 V at 3.0 C, and the winding was performed from the measured discharge capacity. The energy density (Ah / dm ³ ) of the body was calculated. Moreover, the safety test was done according to the following method. The results are shown in Table 1.

  [Safety Test] A non-aqueous secondary battery was placed in an oven, heated to 130 ° C. at a rate of 5 ° C./min, and further allowed to stand at 130 ° C. for 60 minutes. If no rupture or ignition occurred, it was judged as good.

  As shown in Table 1, in the non-aqueous secondary batteries of Examples 1 to 3, the separator thickness a in the flat portion 2 is the portion of the curved portion 3 farthest from the winding center O of the wound body. It is 80% or less of the thickness b of the separator. It was found that the non-aqueous secondary batteries of Examples 1 to 3 were higher in energy density and superior in safety than the non-aqueous secondary battery of Comparative Example 1.

Example 4
[Production of positive electrode]
A positive electrode mixture-containing paste was prepared in the same manner as in Example 1. The paste was applied to both sides of a 15 μm-thick aluminum foil serving as a current collector (active material coating length of 355 mm on the front surface and active material coating length of 285 mm on the back surface), dried to form a positive electrode mixture layer, and then a calendar Processing was performed to adjust the thickness of the positive electrode mixture layer so that the total thickness was 167 μm. Then, it cut | disconnected to width 43mm and length 320mm, and produced the positive electrode. Next, a tab made of aluminum foil was attached to the exposed portion of the aluminum foil (portion where the positive electrode mixture layer was not formed) as the positive electrode terminal lead 4a.

[Production of negative electrode]
A negative electrode mixture-containing paste was prepared in the same manner as in Example 1. The paste was applied to both sides of a 10 μm-thick copper foil serving as a current collector (active material coating length on the front surface 357 mm, active material coating length on the back surface 297 mm) and dried to form a negative electrode mixture layer, and then a calendar The treatment was performed to adjust the thickness of the negative electrode mixture layer so that the total thickness was 145 μm. Then, it cut | disconnected to width 45mm and length 300mm, and produced the negative electrode. Next, a tab made of nickel foil was attached to the exposed portion of the copper foil (portion where the negative electrode mixture layer was not formed) as the positive electrode terminal lead 4a.

  Next, as shown in FIGS. 1A and 1B, the positive electrode 4 and the negative electrode 5, and the porous material 6 produced in the same manner as in Example 1, are used to form a band-shaped laminate, and the laminate is wound. A wound body 1 was produced. The wound body 1 had a structure including 11 layers of a positive electrode and a negative electrode, and the thickness W was 3.93 mm (see FIG. 1B).

Next, the wound body 1 is put in a container 8 prepared using a laminate film having a three-layer structure made of polyester-aluminum-modified polyolefin, and ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1: After 5 ml of an electrolytic solution in which LiPF ₆ was dissolved in the mixed solvent of 2) so as to have a concentration of 1.2 mol / dm ³ was poured into the container 8, the container 8 was vacuum-sealed and left overnight. Next, chemical conversion (preliminary charging) was performed until the voltage reached 3.9 V, the container 8 was once opened and degassed, then resealed and discharged to 3.0 V.

  Next, as shown in FIG. 1D, the wound body 1 is held at 90 ° C. for 30 minutes while pressing the container 8 in which the wound body 1 and the electrolytic solution are held between the two metal plates 9. Put in. Further, the container 8 containing the wound body 1 and the electrolytic solution is left in a thermostat at 90 ° C. for 30 minutes while being pressurized at 10 kPa, and then is taken out from the thermostat and sandwiched between the metal plates 9. And cooled to room temperature.

  Next, when wound body 1 'was taken out from container 8, and thickness of wound body 1' which absorbed electrolyte solution was measured, it was 3.40 mm. Since the thickness (3.40 mm) of the wound body 1 ′ measured in the state of absorbing the electrolytic solution is thinner than the thickness W (3.93 mm) of the wound body 1 before heating and pressurization. It can be seen that the body 1 is thinned by being heated and pressurized. In the flat part 2 (see FIG. 1A) of the wound body 1 ′, the positive electrode 4 and the negative electrode 5 and the separator 7 were joined by an ethylene-vinyl acetate copolymer (see FIG. 1E).

  Next, the wound body 1 ′ taken out from the container 8 is placed in a metal can of a rectangular battery having a width of 34 mm × length of 4.3 mm × height of 50 mm (can wall thickness of 0.3 mm, opening area of 34 mm × 3. 7 mm). Furthermore, after injecting about 0.1 g of the electrolyte into the metal can, the inside of the metal can was sealed to produce a square battery.

(Example 5)
While winding the wound body 1 produced in the same manner as in Example 4 between two metal plates 9, the wound body 1 was placed in a thermostatic bath at 165 ° C. for 5 minutes. Furthermore, after leaving the wound body in a thermostatic bath at 165 ° C. for 3 hours while pressurizing at 100 Pa, it was taken out from the thermostatic bath and cooled to room temperature while being sandwiched between the metal plates 9 (FIG. 3C). When the thickness of wound body 1 'was measured, it was 3.40mm and was thinner than thickness W (3.93mm). In the flat portion 2 (see FIG. 1A) of the wound body 1 ′, the positive electrode 4 and the negative electrode 5 and the separator 7 were joined by an ethylene-vinyl acetate copolymer.

Next, the wound body 1 'is inserted into a metal can of a rectangular battery having a width of 34 mm, a length of 4.3 mm, and a height of 50 mm (can wall thickness, 0.3 mm, opening area: 34 mm × 3.7 mm). Subsequently, an electrolytic solution in which LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1: 2) to a concentration of 1.2 mol / L was used as a metal can. After injecting 2.7 ml, the metal can was sealed and left overnight. Next, chemical conversion (preliminary charging) was performed until the voltage reached 3.9 V, the metal can was once opened and degassed, and then resealed and discharged to 3.0 V.

(Comparative Example 2)
A square battery was produced in the same manner as in Example 5 except that a PE separator (Asahi Kasei Co., Ltd., “N9420”, thickness 20 μm) was used as the porous material. Since the thickness of the wound body 1 ′ was 3.80 mm, it could not be inserted into the metal can of the same rectangular battery as in Example 4, and the rectangular battery could not be produced.

(Comparative Example 3)
A positive electrode having a surface active material coating length of 319 mm, a back surface active material coating length of 250 mm and a thickness of 167 μm, a surface active material coating length of 321 mm, a back surface active material coating length of 262 mm, and a thickness of 145 μm A wound body was produced by winding in the same manner as in Example 5 except that the negative electrode was used and a PE separator (Asahi Kasei Co., Ltd., “N9420”, thickness 20 μm) was used as the porous material. This wound body 1 includes 10 layers of a positive electrode and a negative electrode, the thickness of the wound body 1 before heating and pressing is 3.52 mm, and the thickness of the wound body 1 ′ after heating and pressing. Was 3.52 mm.

Next, the wound body 1 ′ is inserted into the same metal can as in Example 4, and subsequently, the concentration is increased in a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) (volume ratio 1: 2). After injecting 2.8 ml of an electrolyte solution in which LiPF ₆ was dissolved to 1.2 mol / dm ³ into a metal can, the metal can was sealed and left overnight. Next, chemical conversion (preliminary charging) was performed until the voltage reached 3.9 V, the metal can was once opened and degassed, and then resealed and discharged to 3.0 V.

  The nonaqueous secondary batteries of Examples 4 and 5 and Comparative Examples 2 and 3 were charged to 4.2 V, then discharged at 0.2 C until 3.0 V, and the discharge capacity was measured. Moreover, the thickness measurement of the separator and the safety test were performed according to the above-mentioned method. The results are shown in Table 2.

  As is clear from the results shown in Table 2, the non-aqueous secondary batteries of Examples 4 and 5 have a longer discharge capacity and higher energy density than the non-aqueous secondary battery of Comparative Example 3 because the electrodes are longer. At the same time, it was found to be excellent in safety. On the other hand, in Comparative Example 2, since the wound body was thick, the wound body did not enter the metal can and the battery could not be produced.

  According to the non-aqueous secondary battery and the manufacturing method thereof of the present invention, a high-capacity non-aqueous secondary battery can be provided, which is excellent as a non-aqueous secondary battery and a manufacturing method thereof.

Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 1. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 1. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 1. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 1. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 1. Sectional drawing explaining an example of the wound body of the non-aqueous secondary battery of this invention FIG. 2A is an enlarged cross-sectional view of a portion d of the wound body. Enlarged sectional view of part c of the wound body shown in FIG. 2A Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 2. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 2. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 2. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 2. Sectional drawing explaining 1 process of the manufacturing method of the nonaqueous secondary battery of Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 'Winding body 2 Flat part 3 Curved part 4 Positive electrode 5 Negative electrode 6 Porous material 7 Separator 4a Positive electrode terminal lead 5a Negative electrode terminal lead 8 Container 9 Metal plate 10 Inorganic material 11 Polymer blend 12 1st polymer

Claims (15)

A non-aqueous secondary battery including a wound body of a laminate in which a negative electrode, a separator, and a positive electrode are laminated,
The wound body includes a flat portion including the linear separator, and curved portions disposed at both ends of the flat portion including the arc-shaped separator,
The thickness a is 80% or less of the thickness b, where a is the thickness of the separator in the flat portion, and b is the thickness of the separator in the portion of the curved portion farthest from the winding center of the wound body. A non-aqueous secondary battery characterized by the above. The separator includes a semi-compatible or compatible polymer blend and an inorganic material dispersed in the polymer blend, and the polymer blend has a solubility in a predetermined organic solvent at a predetermined temperature of 0.1 g / cm ^3. The nonaqueous secondary battery according to claim 1, comprising the first polymer as described above and a second polymer having the solubility of less than 0.1 g / cm ³ .   The non-aqueous secondary battery according to claim 2, wherein the predetermined temperature is 80 ° C. or higher and 150 ° C. or lower.   The non-aqueous secondary battery according to claim 2, wherein the organic solvent is an electrolyte solution for a non-aqueous secondary battery. The separator includes a semi-compatible or compatible polymer blend and an inorganic material dispersed in the polymer blend. The polymer blend has a first polymer having a melting point of T _m1 ° C and a melting point of T _m2 ° C. The non-aqueous secondary battery according to claim 1, comprising:
However, T _m1 and T _m2 satisfy the relationship of T _m1 <T _m2 .   The first polymer is at least one resin selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ionomer resin, and a vinylidene fluoride-hexafluoropropylene copolymer; The non-aqueous secondary battery according to claim 2, wherein the second polymer is at least one resin selected from the group consisting of polysulfone, polycarbonate, and a styrene-methyl methacrylate copolymer. . The non-aqueous secondary battery according to claim ₂ , wherein the inorganic material is at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , TiO ₂ , montmorillonite, and BaTiO ₂ . (A) A positive electrode, a porous material, and a negative electrode are prepared, and the positive electrode, the porous material, and the negative electrode are stacked so that the porous material is disposed between the positive electrode and the negative electrode. Forming a laminate;
(B) storing the laminate in a container and injecting an organic solvent into the container;
(C) pressurizing while heating the laminate at a predetermined temperature to reduce the thickness of the laminate,
In the step (a), the porous material includes a semi-compatible or compatible polymer blend and an inorganic material dispersed in the polymer blend, and the polymer blend is in the organic solvent at the predetermined temperature. Preparing a material comprising a first polymer having a solubility of 0.1 g / cm ³ or more and a second polymer having a solubility of less than 0.1 g / cm ³ ;
In the step (c), the laminated body is pressurized while eluting a part of the first polymer in the porous material into the organic solvent.   The method for manufacturing a non-aqueous secondary battery according to claim 8, wherein the predetermined temperature is 80 ° C. or higher and 150 ° C. or lower.   The method for producing a nonaqueous secondary battery according to claim 8 or 9, wherein in the step (c), the laminate is pressurized with a pressure of 3 kPa to 700 kPa.   The method for producing a non-aqueous secondary battery according to claim 8, wherein the organic solvent is an electrolyte solution for a non-aqueous secondary battery. (A) A positive electrode, a porous material, and a negative electrode are prepared, and the positive electrode, the porous material, and the negative electrode are stacked so that the porous material is disposed between the positive electrode and the negative electrode. Forming a laminate;
(B) pressurizing while heating the laminate, and reducing the thickness of the laminate,
In the step (a), the porous material includes a semi-compatible or compatible polymer blend and an inorganic material dispersed in the polymer blend, and the polymer blend has a first melting point of T _m1 ° C. A material containing a polymer and a second polymer having a melting point of T _m2 ° C is prepared (however, T _m1 and T _m2 satisfy the relationship of T _m1 <T _m2 ).
In the step (b), the laminate is heated at a temperature not lower than T _m1 ° C. and _lower than T _m2 ° C. to elute a part of the first polymer in the porous material on the surface of the porous material. The method for producing a non-aqueous secondary battery, wherein the laminate is pressurized.   The method for producing a non-aqueous secondary battery according to claim 12, wherein in the step (b), the laminate is pressurized with a pressure of 3 kPa to 700 kPa.   The first polymer is at least one resin selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ionomer resin, and a vinylidene fluoride-hexafluoropropylene copolymer; The nonaqueous secondary battery according to any one of claims 8 to 13, wherein the second polymer is at least one resin selected from the group consisting of polysulfone, polycarbonate, and a styrene-methyl methacrylate copolymer. The non-aqueous secondary battery according to claim 8, wherein the inorganic material is at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , TiO ₂ , montmorillonite, and BaTiO ₂ . Production method.

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