JP2007207438A - Method for manufacturing secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a secondary battery which prevents delamination between a separator and an electrode from occurring due to gas generation. <P>SOLUTION: The method for manufacturing the secondary battery comprises: a step I for forming a positive-electrode laminated body on a surface of a collector (a) so as to create a junction area on the whole periphery of the surface in almost the same width; a step II for forming a negative-electrode laminated body on a surface of a collector (b) so as to create a junction area on the whole periphery of the surface in almost the same width, and so as for a part of the junction area to have a projection projecting outward; a step III for sandwiching a sealing member larger than the negative-electrode laminated body, and a separator between the negative-electrode laminated body and the positive-electrode laminated body, and for sealing them with the projection left open, to form a laminated body; a step IV for injecting an electrolyte from the open end of the projection and for sealing it; a step V for charging the laminated body and for cutting off the projection, to let a gas out; and a step VI for sealing the open end of the projection in the step V. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a secondary battery, particularly a bipolar battery.

  Conventionally, secondary batteries that are superior to other batteries in terms of charge / discharge efficiency, self-discharge rate, load factor discharge characteristics, energy density, etc., are mostly lead-acid batteries and nickel-cadmium secondary batteries. The lithium-ion secondary battery commercialized in 1991 has doubled the weight energy density compared to the conventional secondary battery, leading to a dramatic increase in performance and explosive expansion of applications. It has opened and brought great changes to society.

  At present, bipolar lithium ion secondary batteries with excellent volume energy density are manufactured by providing a negative electrode on one side of a current collector and stacking a positive electrode on the other side through a separator. .

  In Patent Document 1, a battery unit in which a positive electrode and a negative electrode on both sides of a separator impregnated with a gel electrolyte are formed and stacked, and a voltage check and a capacity check can be performed for each battery unit. However, although the voltage can be concentrated on a battery unit and damage can be prevented, there is a problem of power generation efficiency due to the reduction of the contact area between the gel electrolyte and the separator and the electrode due to the gas generated by the reaction between the electrolyte and the active material during discharge. is there.

  In Patent Document 2, a bipolar battery that has a detection tab as a sub tab for monitoring the voltage of each battery unit layer in a bipolar battery and is excellent in waterproofness, airtightness, etc. because it is covered with resin. It is. In addition, since the entire periphery of the battery element is covered with a resin and sealed, the pressure between the electrodes can be maintained at a uniform pressure. However, after sealing, there is a problem that the separator, the electrolyte, and the electrode cause delamination due to the gas generated from the inside of the battery element.

  Patent Document 3 is a bipolar battery in which a plurality of unit cells using a polymer electrolyte gel are stacked to prevent a liquid junction between the unit cells, and since the sealing layer is composed of two types of resins, the temperature of heat welding Can be performed at a low temperature, and is a bipolar battery excellent in adhesion between electrodes. However, the gas generated by the reaction between the electrode and the electrolyte cannot be effectively suppressed / prevented, and there is a problem that the separator and the electrode cause delamination.

In Patent Document 4, a bipolar battery has a structure that surrounds a single cell and has a structure in which a seal layer protrudes to the outside of the current collector to prevent a short circuit between the electrodes. Cannot be effectively suppressed / prevented, and there is a problem that the separator and the electrode cause delamination.
JP-A-11-204136 JP 2005-5163 A JP 2004-158343 A JP 2003-427490 A

  In order to solve the above problems, an object of the present invention is to provide a secondary battery in which a gas generated by an electrode reaction is removed in advance, and delamination between the separator and the electrode due to the gas is suppressed / prevented.

The present invention provides a method for producing a secondary battery in which a current collector provided with a positive electrode active material and a negative electrode active material, and a separator are laminated,
Step (I) of forming a positive electrode active material layer on one surface of the current collector (a) so that the bonding region is formed with substantially the same width over the entire circumference to obtain a positive electrode laminate;
The negative electrode active material layer is formed on one surface of the current collector (b) so that the bonding region is formed with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. Forming a negative electrode laminate (II);
A larger sealing material than the negative electrode laminate obtained in the step (II), and a separator comprising the negative electrode laminate obtained in the step (II) and the positive electrode laminate obtained in the step (I). Step (III) of forming a laminated body having an open end by sealing so as to open the protrusion after being sandwiched between them;
Step (IV) of sealing the open end after injecting an electrolyte from the open end;
Step (V) of charging the laminate obtained in the step (IV), cutting the projecting portion, forming an open end portion again, and degassing;
Step (VI) of sealing again the open end of Step (V)
It can achieve by the manufacturing method of the secondary battery which has these. In addition, in the manufacturing method of the said secondary battery, even if it replaces a positive electrode and a negative electrode, it can achieve.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness and contact area between the separator which has electrolyte, and an electrode can be improved, and electrode reaction can advance rapidly.

  In the method for producing a secondary battery according to the present invention, in which a current collector provided with a positive electrode active material and a negative electrode active material and a separator are laminated, a bonding region is provided on one side of the current collector (a) over the entire circumference. Step (I) of forming a positive electrode active material layer so as to have substantially the same width to obtain a positive electrode laminate; a bonding region is formed on one side of the current collector (b) with substantially the same width over the entire circumference. And forming a negative electrode active material layer so that a part of the bonding region has a protruding portion protruding outward, thereby obtaining a negative electrode laminate (II); obtained in the step (II). After sandwiching the sealing material larger than the obtained negative electrode laminate and the separator between the negative electrode laminate obtained in the step (II) and the positive electrode laminate obtained in the step (I), The projecting part is sealed so as to be opened to form a laminate having an open end. Step (III): After injecting an electrolyte from the open end, sealing the open end (IV); charging the laminate obtained in the step (IV); Steps (V) for cutting, forming an open end again, and degassing; Step (VI) for resealing the open end in step (V) Each will be described with reference to FIGS. In the following description, an embodiment is described in which a positive electrode active material layer is formed on a current collector (a) that does not have a protrusion, and a negative electrode active material layer is formed on a current collector (b) that has a protrusion. Although described, the present invention is not limited to the above, and the present invention forms a negative electrode active material layer on a current collector (a) that does not have a protruding portion and has a protruding portion ( b) includes an embodiment in which a positive electrode active material layer is formed. In this case, in the following description, the positive electrode active material and the negative electrode active material may be replaced with each other.

Step (I) and Step (II) and Step (i) and Step (ii)
First, a positive electrode active material layer is formed on one surface of the current collector (a) so that bonding regions are formed with substantially the same width over the entire circumference, and a positive electrode laminate is obtained. On the other hand, the negative electrode active material is formed on one surface of the current collector (b) so that the bonding region is formed with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. A layer is formed to obtain a negative electrode laminate. In the positive electrode laminate and the negative electrode laminate, the positive electrode active material and the negative electrode active material may be interchanged.

  That is, as shown in FIG. 1-A, when the positive electrode active material is provided on one side of the current collector (a) 2, a region provided with the active material (also simply referred to as a layer of the positive electrode active material) is provided. There is a region that is not formed (also simply referred to as a bonding region, where the current collector is exposed). The positive electrode active material layer 4 is formed to have substantially the same width, preferably the same width, over the entire circumference so as to be surrounded by the bonding region.

  On the other hand, as shown in FIG. 1-B, when the negative electrode active material is provided on one side of the current collector (b) 1, the negative electrode active material layer 5 and the bonding region exist and are surrounded by the bonding region. In this case, the current collector (b) is formed so that a part of the bonding region protrudes outwardly. Have

  In other words, as shown in the drawing, the current collector (b) 1 has a part of the bonding region, which is a portion where the negative electrode active material layer 5 of FIG. It differs from the current collector (a) 2 in that it has a protruding portion 7 larger than the bonding region, which is a portion where the material layer 4 is not provided. 1A, the positive electrode active material layer 4 is provided on the current collector (a) 2, and in FIG. 1B, the negative electrode active material layer 5 is provided on one side of the current collector (b) 1. The negative electrode active material layer and the positive electrode active material layer may be interchanged.

  In other words, the protruding portion 7 in which a part of the bonding region protrudes to the outside is defined by the inner periphery and the outer periphery of the bonding region when the positive electrode active material layer 4 is provided on one surface of the current collector (a) 2. Comparing the maximum distance 11 with the maximum distance 8 between the inner periphery and the outer periphery of the bonding region when the negative electrode active material layer 5 is provided on one surface of the current collector (b) 1, the latter is longer. Preferably, the areas of the positive electrode active material layer and the negative electrode active material layer are the same.

  The difference between the maximum distance 11 between the inner periphery and the outer periphery and the maximum distance 8 between the inner periphery and the outer periphery needs to be greater than or equal to twice the maximum distance 11, and is preferably within three times. If the difference between the maximum distance 11 between the inner periphery and the outer periphery and the maximum distance 8 between the inner periphery and the outer periphery is less than twice, a joint region for two times cannot be provided, and if the difference is more than three times, Therefore, the material to be cut is large, which is not preferable in terms of cost.

  In other words, the protruding portion 7 in which a part of the bonding region protrudes outward is the positive electrode laminate in which the positive electrode active material layer 4 is provided on one side of the current collector (a) 2, and the current collector. When the negative electrode laminate in which the negative electrode active material layer 5 is provided on one side of the body (b) 1 is laminated so that the positive electrode active material layer 4 and the negative electrode active material layer 5 overlap in the thickness direction. The portion of the current collector (b) 1 that protrudes outward by a preferable length as described in detail below as compared to the electric body (a) 2 is meant. In the present invention, the positive electrode active material layer and the negative electrode active material layer preferably have the same area.

When used as a bipolar battery, a positive electrode active material layer is formed on one surface of the current collector (a) so that bonding regions are formed with substantially the same width over the entire circumference, and the positive electrode active material is formed on the other surface. A layer of the negative electrode active material is formed so as to be symmetric (so-called front and back integration) with the above layer to obtain an electrode laminate (A).
On the other hand, the negative electrode active material is formed so that the bonding region is formed on the one surface of the current collector (b) with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. The positive electrode active material layer is formed on the other surface so as to be symmetrical to the negative electrode active material layer and to have a protruding portion in which a part of the bonding region protrudes outward. An electrode laminate (B) is obtained.

  In the present invention, the shape of the active material layer is appropriately determined depending on the purpose, and specifically, a polygon such as a square, a rectangle, a rhombus, a parallelogram, and a regular hexagon, and a circular curve such as a circle and an ellipse. Preferably, it is a square. The present invention can achieve the object in any shape, and the scope of the invention is not limited by the shape.

  Examples of the method for forming an active material according to the present invention include a coating method, spray spraying, a method of creating a frame in advance and pouring it into the frame.

  The substantially same width of the bonding region according to the present invention means that the bonding region in which the active material layer is not formed in the current collector has substantially the same width. It is not necessary to specify the length of the seal layer, the separator, the negative electrode laminate, and the positive electrode laminate in the subsequent step (III) can prevent liquid junction, and in step (V) The size is not particularly limited as long as the cut protrusion can be resealed, and varies depending on the size of the current collector, the size of the active material layer, and the like.

"Current collector"
The current collector (a) that can be used in the present invention is not particularly limited, and conventionally known ones can be used. For example, aluminum foil, stainless steel (SUS) foil, titanium foil, nickel-aluminum clad material, copper-aluminum clad material, SUS-aluminum clad material, or a plating material of a combination of these metals can be preferably used. Further, a current collector in which a metal surface is coated with aluminum may be used. Moreover, you may use the electrical power collector which bonded 2 or more metal foil depending on the case. When the composite current collector is used, as a material for the positive electrode current collector, for example, a conductive metal such as aluminum, an aluminum alloy, SUS, or titanium can be used, and aluminum is particularly preferable. On the other hand, as the material of the negative electrode current collector, for example, conductive metals such as copper, nickel, silver, and SUS can be used, and SUS and nickel are particularly preferable. Further, in the composite current collector, the positive electrode current collector and the negative electrode current collector may be electrically connected to each other directly or via a conductive intermediate layer made of a third material.

  The current collector (b) used in the present invention may be the same as the current collector (a).

  Each thickness of the positive electrode current collector and the negative electrode current collector in the composite current collector may be as usual, and both current collectors are, for example, about 5 to 30 μm.

  In addition, the area of the current collector (a) according to the present invention is appropriately determined according to its purpose, and similarly, the area of the current collector (b) according to the present invention is appropriately determined according to its purpose. Is.

“Positive electrode active material layer (positive electrode layer)”
The constituent material of the positive electrode layer according to the present invention may be any material as long as it contains a positive electrode active material, and further, if necessary, a conductive assistant for increasing electronic conductivity, a binder, and an electrolyte for increasing ionic conductivity. Support salts (lithium salts), polymer electrolytes, additives, etc. may be included, but when a polymer gel electrolyte or liquid electrolyte is used for the electrolyte layer, conventionally known binders that bind positive electrode active material fine particles to each other, electronic conduction For example, a conductive auxiliary agent for enhancing the properties may be included, and a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte may not be included. Even when a liquid electrolyte is used for the electrolyte layer, the positive electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte.

As the positive electrode active material according to the present invention, a composite oxide of lithium and transition metal (lithium-transition metal composite oxide) can be suitably used. Specifically, Li—Mn composite oxides such as LiMnO ₂ and LiMn ₂ O ₄ , Li—Co composite oxides such as LiCoO ₂ , Li—Cr such as Li ₂ Cr ₂ O ₇ and Li ₂ CrO _4. Li-Ni composite oxides such as LiNiO ₂ , Li-Fe composite oxides such as Li _x FeO _y and LiFeO _2, and Li-V composite oxides such as Li _x V _y O _z And selected from Li metal oxides such as those obtained by substituting a part of these transition metals with other elements (for example, LiNi _x Co _1-x O ₂ (0 <x <1), etc.) However, the present invention is not limited to these materials. These lithium-transition metal composite oxides are excellent in reactivity and cycle durability and are low-cost materials. Therefore, using these materials for the electrodes is advantageous in that a battery having excellent output characteristics can be formed. In addition, transition metal and lithium phosphate compounds and sulfate compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned. Among the positive electrode active materials, a Li—Mn-based composite oxide is preferable. This is because (1) the profile can be tilted and (2) the reliability at the time of abnormality is improved by using the Li—Mn-based composite oxide. As a result, there is an advantage that the voltage of each single cell layer and the entire bipolar battery can be easily detected.

  In order to reduce the electrode resistance of the bipolar battery, the positive electrode active material preferably has a particle diameter smaller than that generally used in non-bipolar lithium ion secondary batteries.

  Examples of the conductive aid include acetylene black, carbon black, graphite, various carbon fibers, and carbon nanotubes. However, it is not necessarily limited to these.

  As the binder, polyvinylidene fluoride (PVDF), SBR, polyimide and the like can be used, but the present invention is not limited to these.

  Among the above electrolytes, the polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte solution used in a lithium ion secondary battery that is not bipolar type, and further has lithium ion conductivity. A structure in which a similar electrolyte solution is held in a non-polymeric skeleton is also included. Therefore, the polymer solid electrolyte among the electrolytes becomes a polymer solid electrolyte having ion conductivity.

Here, the electrolytic solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte is not particularly limited, and various conventionally known electrolytic solutions can be appropriately used. For example, inorganic acid anion salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiBOB (lithium bisoxide borate), LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, at least one kind selected from organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N (lithium bis (perfluoroethylenesulfonylimide); also referred to as LiBETI) Cyclic carbonates such as propylene carbonate and ethylene carbonate; lithium carbonate (electrolyte salt); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; A material using a plasticizer (organic solvent) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof can be used. However, it is not necessarily limited to these.

  Examples of the solid polymer electrolyte having ion conductivity include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

  Examples of the polymer having no lithium ion conductivity used for the polymer gel electrolyte include polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). . However, it is not necessarily limited to these. Note that PAN, PMMA, etc. are in a class that has almost no ionic conductivity, and therefore can be a polymer having the above ionic conductivity, but here, they are used for a polymer gel electrolyte. This is exemplified as a polymer having no lithium ion conductivity.

The ion as the conducting electrolyte supporting salts to improve the (lithium salt), for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl ₁₀ and the like inorganic acid anion A salt, an organic acid anion salt such as Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, or a mixture thereof can be used. However, it is not necessarily limited to these.

  The ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10. That is, the leakage of the electrolyte from the electrolyte material in the battery electrode can be effectively sealed by forming an insulating layer described later. Therefore, it is possible to give priority to battery characteristics relatively with respect to the ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte.

  Examples of the additive include trifluoropropylene carbonate for enhancing battery performance and life, and various fillers as reinforcing materials.

  The thickness of the positive electrode layer (positive electrode active material film thickness) is not particularly limited, and is determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity, as described for the blending amount. However, it should be determined in consideration of the intended use of the battery (emphasis on output, energy, etc.) and ion conductivity.

  The amount of positive electrode active material, conductive additive, binder, polymer electrolyte (host polymer, electrolyte, etc.), lithium salt, etc. in the positive electrode layer depends on the intended use of the battery (output priority, energy priority, etc.), ion conductivity Should be taken into consideration.

“Layer of negative electrode active material (negative electrode layer)”
The negative electrode layer according to the present invention includes a negative electrode active material active material. In addition to this, a conductive auxiliary agent for increasing electronic conductivity, a binder, a polymer electrolyte (host polymer, electrolytic solution, etc.), a lithium salt for increasing ionic conductivity, an additive, etc. may be included. When a polymer gel electrolyte is used for the molecular electrolyte layer, it only needs to contain a conventionally known binder that binds the negative electrode active material fine particles to each other, a conductive auxiliary agent for increasing electronic conductivity, and the like. The host polymer, electrolyte solution, lithium salt and the like may not be contained. Even when a solution electrolyte is used for the electrolyte layer, the negative electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte. Since the contents other than the type of the negative electrode active material are basically the same as the contents described in the section “Positive electrode”, the description is omitted here.

As the negative electrode active material according to the present invention, a negative electrode active material that is also used in a solution-type lithium ion battery can be used. Specifically, carbon, metal compounds, metal oxides, Li metal compounds, Li metal oxides (including lithium-transition metal composite oxides), boron-added carbon, graphite, and the like can be used. These may be used alone or in combination of two or more. Examples of the carbon include conventionally known carbon materials such as graphite carbon, hard carbon, and soft carbon. Examples of the metal compound include LiAl, LiZn, Li ₃ Bi, Li ₃ Cd, Li ₃ Sd, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, Li _{0. 17} C (LiC ₆ ) and the like. The metal _{oxides, SnO, SnO 2, GeO,} GeO 2, In 2 O, In 2 O 3, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4, Ag 2 O, AgO, Ag 2 O ₃ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , SiO, ZnO, CoO, NiO, FeO and the like. Examples of the Li metal compound include Li ₃ FeN ₂ , Li _2.6 Co _0.4 N, Li _2.6 Cu _0.4 N, and the like. Examples of the Li metal oxide (lithium-transition metal composite oxide) include a lithium-titanium composite oxide represented by Li _x Ti _y O _z such as Li ₄ Ti ₅ O ₁₂ . Examples of the boron-added carbon include boron-added carbon and boron-added graphite. However, in this invention, it should not be restrict | limited to these but a conventionally well-known thing can be utilized suitably. The boron content in the boron-added carbon is preferably in the range of 0.1 to 10% by mass, but should not be limited to this. Preferably, the material is selected from a crystalline carbon material and an amorphous carbon material. By using these, the profile can be tilted, and the voltage of each single cell layer and the entire bipolar becomes easy to detect. The crystalline carbon material here refers to a graphite-based carbon material, and includes the above-described graphite carbon and the like. The non-crystalline carbon material refers to a hard carbon-based carbon material, and includes the hard carbon and the like.

Step (III) and Step (iii)
A larger sealing material than the negative electrode laminate obtained in the step (II), and a separator comprising the negative electrode laminate obtained in the step (II) and the positive electrode laminate obtained in the step (I). After being sandwiched in between, the projecting portion is sealed so as to be opened to form a laminate having an open end.

  Although the specific method (for example, the order of lamination | stacking of each member) of the said process (III) and (iii) is not restrict | limited in particular, In the process 1-process 4 shown, for example in FIG. 1, FIG. A sealing material is laminated and temporarily fixed (step 1), a separator is placed thereon (step 2), and a negative electrode laminate is further placed thereon (step 3) to form an open end. Then, the three sides other than the side with the protruding portion are sealed (step 4). As shown in step 2 of FIG. 1, the sealing material is cut out at a portion that is the same as or larger than the outer edge shape of the portion provided with the positive electrode active material or the negative electrode active material (positive electrode active material layer or negative electrode active material layer). It has been.

  In the step 1, the sealing material is temporarily fixed to the positive electrode laminate, but the negative electrode laminate may be temporarily fixed first. As a result, the separator and the negative electrode laminate are interposed between the positive electrode laminate and the negative electrode laminate. What is necessary is just to take the structure where a sealing material is clamped. Temporary fastening is intended to fix the sealing material to the positive electrode laminate or the negative electrode laminate, and is not limited to the means.

  In FIG. 1 and FIG. 2, as an example of the embodiment, the shape of the outer edge of the portion provided with the positive electrode laminate or the negative electrode laminate is square, so that three sides are sealed. For example, the positive electrode laminate or the negative electrode laminate In the case where the shape of the outer edge of the portion provided with the body is a circle, an open end may be provided at a part of the circumference so that the protruding portion is opened, and the present invention provides a positive electrode laminate or a negative electrode laminate. It is not limited to the shape of the outer edge of the part provided with the shape of the open part.

  As shown in Steps 1 and 3 of FIG. 1, the sealing material of the present invention is a sealing material having such a size as to completely include the junction region of the current collector (a) and the current collector (b). Yes, it acts as an insulating layer that is provided around the single battery cell and is sandwiched by the current collectors located above and below, and short-circuits between the positive electrode active material layer and the negative electrode active material layer (liquid junction) ) Means a layer capable of preventing).

  Further, the sealing material preferably has a low melting point and a heat welding property. Thereby, the current collector (a), the separator, and the current collector (b) are thermally welded by heat-pressing at a temperature lower than the melting point of the sealing material.

  The heat welding temperature according to the present invention is preferably 100 ° C. or lower.

  The sealing material according to the present invention is used as a battery exterior material. In general, a polymer metal composite film in which a heat-welding resin film, a metal foil, and a rigid resin film are laminated in this order is used.

  For example, polyethylene (PE), polypropylene (PP), modified polyethylene, modified polypropylene, ionomer, ethylene vinyl acetate (EVA), and the like can be used as the heat welding heat welding resin. As the metal foil, for example, Al foil or Ni foil can be used. As the resin having rigidity, polyamide synthetic fibers such as polyester such as polyethylene terephthalate (PET) and polyamide (nylon (registered trademark)) can be used. Specifically, a PE / Al foil / PET laminated film laminated from the sealing surface side to the outer surface; a PE / Al foil / nylon (registered trademark) laminated film; an ionomer / Ni foil / PET laminated film; EVA / Al foil / PET laminated film; ionomer / Al foil / PET laminated film and the like can be used. The heat-welding heat-welding resin film acts as a seal layer when the battery element is housed inside. A metal foil or a rigid resin film imparts moisture, breathability, and chemical resistance to the exterior material. The laminate sheet can be easily and reliably bonded using heat welding, heat sealing such as heat sealing, impulse sealing, ultrasonic welding, and high frequency welding.

"Separator (hereinafter also referred to as electrolyte layer)"
The separator in the present invention includes (a) a polymer gel electrolyte layer, (b) a polymer solid electrolyte layer, or (c) a separator (nonwoven fabric separator) impregnated with these polymer electrolyte or electrolyte depending on the purpose of use. ).

(A) Polymer gel electrolyte layer The polymer gel electrolyte is not particularly limited, and those used in conventional gel electrolyte layers can be appropriately used. Here, the gel electrolyte refers to one in which an electrolytic solution is held in a polymer matrix. In the present invention, the difference between an all solid polymer electrolyte (also simply referred to as a polymer solid electrolyte) and a gel electrolyte is as follows.

  A gel electrolyte is an all-solid polymer electrolyte such as polyethylene oxide (PEO) containing an electrolytic solution used in a normal lithium ion battery.

  A gel electrolyte is a polymer electrolyte such as polyvinylidene fluoride (PVDF) in which a polymer skeleton having no lithium ion conductivity is held.

  -The ratio of the polymer constituting the gel electrolyte (also referred to as host polymer or polymer matrix) and the electrolytic solution is wide. When 100% by mass of the polymer is an all solid polymer electrolyte and 100% by mass of the electrolytic solution is a liquid electrolyte, an intermediate thereof Are all gel electrolytes.

  A host polymer of the gel electrolyte is not particularly limited, and a conventionally known one can be used. Preferably, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG ), Polyacrylonitrile (PAN), polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), poly (methyl methacrylate) (PMMA) and copolymers thereof are preferable, and the solvents include ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof are preferred.

The electrolyte solution (electrolyte salt and plasticizer) of the gel electrolyte is not particularly limited, and conventionally known ones can be used. Specifically, as long as usually used in a lithium ion battery, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl ₁₀ and the like inorganic acid anion At least one lithium salt (electrolyte salt) selected from organic acid anion salts such as a salt, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N ), Cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane , 1,2-dibutoxyethane, etc. Lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; at least one or more selected from methyl acetate and methyl formate A mixed organic solvent (plasticizer) such as an aprotic solvent can be used. However, it is not necessarily limited to these.

  The ratio of the electrolytic solution in the gel electrolyte in the present invention is not particularly limited, but is preferably about several mass% to 98 mass% from the viewpoint of ionic conductivity. The present invention is particularly effective for a gel electrolyte having a large amount of electrolytic solution in which the proportion of the electrolytic solution is 70% by mass or more.

  In the present invention, the amount of the electrolyte contained in the gel electrolyte may be substantially uniform inside the gel electrolyte, or may be decreased in an inclined manner from the central portion toward the outer peripheral portion. . The former is preferable because reactivity can be obtained in a wider range, and the latter is preferable in that the sealing property of the all solid polymer electrolyte portion in the outer peripheral portion with respect to the electrolytic solution can be improved. When decreasing gradually from the central part toward the outer peripheral part, polyethylene oxide (PEO), polypropylene oxide (PPO) and copolymers thereof having lithium ion conductivity are used as the host polymer. It is desirable.

(B) Polymer solid electrolyte layer The all solid polymer electrolyte is not particularly limited, and a conventionally known one can be used. Specifically, it is a layer composed of a polymer having ion conductivity, and the material is not limited as long as it exhibits ion conductivity. Examples of the all solid polymer electrolyte include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid polymer electrolyte contains a lithium salt in order to ensure ionic conductivity. As the lithium salt, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these. A polyalkylene oxide polymer such as PEO and PPO can dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

(C) Separator (including non-woven fabric separator) impregnated with the polymer electrolyte or electrolytic solution (electrolyte salt and plasticizer)
As the electrolyte that can be impregnated in the separator, the same electrolyte (electrolyte salt and plasticizer) solution as described in (a) and (b) or (a) described above can be used. The description in is omitted.

  The separator is not particularly limited, and a conventionally known separator can be used. For example, a porous sheet made of a polymer that absorbs and holds the electrolyte (for example, a polyolefin microporous separator). Etc.) can be used. The polyolefin microporous separator having the property of being chemically stable to an organic solvent has an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low.

  Examples of the polymer material include polyethylene (PE), polypropylene (PP), a laminate having a three-layer structure of PP / PE / PP, and polyimide.

  The thickness of the separator cannot be unambiguously defined because it varies depending on the intended use. However, in the case of a secondary battery for driving a motor such as an electric vehicle (EV) or a hybrid electric vehicle (HEV), a single layer is used. Or it is desirable that it is 4-60 micrometers in a multilayer. The mechanical strength in the thickness direction is desirable because the thickness of the separator is within such a range, and it is desirable to narrow the gap between the electrodes for high output and prevention of short-circuiting caused by fine particles entering the separator. And there is an effect of ensuring high output performance. In addition, when a plurality of batteries are connected, the electrode area increases, so that it is desirable to use a thick separator in the above range in order to increase the reliability of the battery.

  The fine pore diameter of the separator is desirably 1 μm or less (usually a pore diameter of about several tens of nm). When the average diameter of the micropores in the separator is within the above range, the “shutdown phenomenon” that the separator melts due to heat and the micropores close quickly occurs, resulting in higher reliability during abnormalities, resulting in heat resistance. Has the effect of improving. In other words, when the battery temperature rises due to overcharging (in an abnormal state), the “shutdown phenomenon” that the separator melts and closes the micropores occurs quickly, so that the positive electrode (+) of the battery (electrode) Li ions cannot pass through to the negative electrode (−) side, and no further charge is possible. As a result, overcharging cannot be performed and overcharging is eliminated. As a result, in addition to improving the heat resistance (safety) of the battery, it is possible to prevent gas from being released and the heat-welded part (seal part) of the battery exterior material from opening. Here, the average diameter of the micropores of the separator is calculated as an average diameter obtained by observing the separator with a scanning electron microscope or the like and statistically processing the photograph with an image analyzer or the like.

  The separator preferably has a porosity of 20 to 50%. The separator's porosity is within the above range, preventing output from being reduced due to the resistance of the electrolyte (electrolyte), and preventing the short circuit caused by fine particles penetrating the separator's pores (micropores). It has the effect of securing both sexes. Here, the porosity of the separator is a value obtained as a volume ratio from the density of the raw material resin and the density of the separator of the final product.

  The amount of electrolyte impregnated into the separator may be impregnated up to the holding capacity range of the separator, but may be impregnated beyond the holding capacity range. This can be impregnated as long as it can be retained in the electrolyte layer because a seal portion is provided in the electrolyte and the electrolyte solution can be prevented from exuding from the electrolyte layer.

  The nonwoven fabric separator used for holding the electrolyte is not particularly limited, and can be manufactured by entwining the fibers into a sheet. Moreover, the spun bond etc. which are obtained by fusing fibers by heating can also be used. In other words, it may be in the form of a sheet formed by arranging fibers in a web (thin cotton) shape or mat shape by an appropriate method, and joining them using an appropriate adhesive or the fusing force of the fibers themselves. The adhesive is not particularly limited as long as it has sufficient heat resistance at the temperature during manufacture and use, and is stable without any reactivity or solubility with respect to the gel electrolyte. In addition, conventionally known ones can be used. In addition, the fiber used is not particularly limited, and for example, conventionally known fibers such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene such as polyethylene, polyimide, and aramid can be used. Depending on (such as mechanical strength required for the electrolyte layer), they are used alone or in combination. Further, the bulk density of the nonwoven fabric is not particularly limited as long as sufficient battery characteristics can be obtained by the impregnated polymer gel electrolyte. That is, if the bulk density of the nonwoven fabric is too large, the proportion of the non-electrolyte material in the electrolyte layer becomes too large, which may impair the ionic conductivity in the electrolyte layer.

  The porosity of the nonwoven fabric separator is preferably 50 to 90%. If the porosity is less than 50%, the electrolyte retention deteriorates, and if it exceeds 90%, the strength is insufficient. Furthermore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer, preferably 5 to 200 μm, particularly preferably 10 to 100 μm. When the thickness is less than 5 μm, the electrolyte retention deteriorates, and when it exceeds 200 μm, the resistance increases.

  In addition, you may use together the electrolyte layer of said (a)-(b) in one battery.

  In addition, the polymer electrolyte may be contained in the electrolyte layer, the positive electrode active material layer, and the negative electrode active material layer, but the same polymer electrolyte may be used, or different polymer electrolytes may be used depending on the layer.

  By the way, a host polymer for a polymer electrolyte that is preferably used at present is a polyether polymer such as PEO and PPO. For this reason, the oxidation resistance on the positive electrode side under high temperature conditions is weak. Therefore, when using a positive electrode agent having a high oxidation-reduction potential that is generally used in a solution-type lithium ion battery, the capacity of the negative electrode is preferably smaller than the capacity of the positive electrode facing through the polymer electrolyte layer. . If the capacity of the negative electrode is less than the capacity of the opposing positive electrode, it is possible to prevent the positive electrode potential from rising excessively at the end of charging. In addition, the capacity | capacitance of a positive electrode and a negative electrode can be calculated | required from manufacturing conditions as theoretical capacity | capacitance at the time of manufacturing a positive electrode and a negative electrode. You may measure the capacity | capacitance of a finished product directly with a measuring device.

  However, if the capacity of the negative electrode is smaller than the capacity of the opposing positive electrode, the negative electrode potential will be too low and the durability of the battery may be impaired, so it is necessary to pay attention to the charge / discharge voltage. For example, care should be taken not to lower the durability by setting the average charge voltage of one cell (single cell layer) to an appropriate value for the oxidation-reduction potential of the positive electrode active material. The thickness of the electrolyte layer constituting the battery is not particularly limited. However, in order to obtain a compact bipolar polymer battery, it is preferable to make it as thin as possible as long as the function as an electrolyte can be secured. The thickness of a general electrolyte layer is 5 to 200 μm, preferably about 10 to 100 μm.

Step (IV) and Step (iv)
Further, after injecting the electrolyte from the open end, the open end is sealed.

In Steps 5 to 6 shown in FIG. 2, a predetermined amount of electrolyte is injected from the open end of the laminate in which the separator and the sealing material are sandwiched between the unsealed envelope-shaped positive electrode and the negative electrode (Step 5), Thereafter, the injected open end, preferably the outer edge of the open end, is sealed to form a laminate having the open end (step 6). As the electrolytic solution according to the present invention, the same electrolytes as those mentioned above for the positive electrode, negative electrode, and separator can be used, and are not particularly limited, and various conventionally known electrolytic solutions can be appropriately used. Is. For example, inorganic acid anion salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiBOB (lithium bisoxide borate), LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, at least one kind selected from organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N (lithium bis (perfluoroethylenesulfonylimide); also referred to as LiBETI) Cyclic carbonates such as propylene carbonate and ethylene carbonate; lithium carbonate (electrolyte salt); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; A material using a plasticizer (organic solvent) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof can be used. However, it is not necessarily limited to these.

  The amount of the electrolytic solution according to the present invention is appropriately determined depending on the purpose.

  As the sealing method according to the present invention, it is preferable that the sealing is performed by the heat welding property (please describe if there are other examples) as described above. Moreover, although an open end part is sealed in the said process, although the sealing part is not restrict | limited in particular, After cut | disconnecting the protrusion inside the said sealing part in subsequent process (V) and (VI) In consideration of sealing again, as described above, the outer edge portion of the open end is preferable as shown in Step 6 of FIG.

Steps (V) and (VI) and Steps (v) and (vi)
In this step, after charging the laminate obtained in the steps (IV) and (iv), the protruding portion is cut, an open end is formed again, and degassing is performed.

As a charging method according to the present invention (please describe the charging method while briefly explaining the device name etc.)
In addition, after charging, the protruding portion is cut, but the cutting portion is a protruding portion that does not include the positive electrode active material layer and the negative electrode active material layer. After forming the gas, degassing is performed. Finally, after the degassing, the cut portion is sealed again.

  In Steps 7 to 9 shown in FIG. 3, since gas is generated in the stacked body by charging, the dotted line portion of the sealed outer edge is opened (Steps 7 and 8), and the gas inside is removed (Step 9). Since the region for joining the current collector (a) in step (I) and step (II) and step (i) and step (ii) is larger than the region for joining the current collector (b), A positive electrode active material layer and a negative electrode active material layer having the same area can be secured. Moreover, since the sealing material is made larger than the current collector (a), problems such as battery adhesion and liquid junction can be suppressed / prevented. Furthermore, the gas generated by the electrode reaction can be removed in advance, and the generation of the gas can suppress / prevent partial peeling between the separator and the electrode, and can also prevent inhibition of the electrode reaction due to peeling.

  In addition, about the manufacturing method concerning this invention, when producing as a bipolar battery, only a difference of said process (i) and (ii), Comprising: Other processes can be performed similarly to said process. The resealing method after degassing is not particularly limited, and a known method can be used. Preferably, the same method as described in the above steps (III) and (iii) can be used.

  In the present invention, the above battery can be used as a bipolar battery, and at least two or more bipolar batteries can be connected in series or in parallel (series-parallel connection) to form an assembled battery module. This makes it possible to meet the demands for capacity and voltage for various vehicles with a combination of basic bipolar batteries. As a result, design selectivity of required energy and output can be facilitated, and it is not necessary to design and produce different bipolar batteries for various vehicles, enabling mass production of basic bipolar batteries. Cost reduction by mass production becomes possible.

  Further, in the assembled battery module of the present invention, the bipolar battery of the present invention, a battery having the same voltage as the bipolar battery and the positive and negative electrode materials made in series, and having the same number of constituent units of the bipolar battery (non-bipolar lithium) An ion secondary battery) may be connected in parallel. That is, the bipolar battery forming the assembled battery module may be a mixture of the bipolar battery of the present invention and a conventional non-bipolar lithium ion secondary battery or the like. As a result, an assembled battery module that compensates for each other's weaknesses by a combination of an output-oriented bipolar battery and an energy-oriented general lithium ion secondary battery can be formed, and the weight and size of the assembled battery module can be reduced. The proportion of each bipolar battery and non-bipolar battery to be mixed is determined according to the safety performance and output performance required for the assembled battery module. In addition, the above-described bipolar secondary battery is connected in series and parallel to form a first assembled battery unit, and secondary batteries other than bipolar batteries having the same voltage and voltage between the terminals of the first assembled battery unit are connected in series and parallel. It is good also as an assembled battery module by forming the 2nd assembled battery unit formed by connecting, and connecting this 1st assembled battery unit and a 2nd assembled battery unit in parallel.

  In the present invention, not only the assembled battery but also an assembled battery module may be mounted depending on the intended use, or the assembled battery and the assembled battery module may be mounted in combination. Further, as the vehicle on which the assembled battery or the assembled battery module of the present invention can be mounted as a driving power source or an auxiliary power source, the above-described electric vehicle, fuel cell vehicle, and hybrid vehicle thereof are preferable, but are not limited thereto. It is not a thing. Moreover, as a vehicle in which the assembled battery module and / or the assembled battery of the present invention can be mounted as, for example, a driving power source or an auxiliary power source, an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel cell vehicle, etc. However, it is not limited to these.

  The technical scope of the present invention is not limited to the following examples. Process 1 is a comparative example which is a conventional technique, and process 2 is an example according to the present invention.

Production of electrodes (1)
(Positive electrode slurry)
100 g of a positive electrode active material (LiMn ₂ O ₄ ) and 5 g of a conductive additive (carbon black) were weighed, 5 g of polyvinylidene fluoride (PVdF) was added as a binder to the above mixture, and mixing was performed with a mixer. Further, an appropriate amount of N methyl 2-pyrrolidone (NMP) was added as a solvent so that the viscosity was 7000 cP, and the slurry was prepared by vacuum mixing.

(Negative electrode slurry)
N-methyl-2-pyrrolidone (NMP) as a solvent was added to 90% by mass of hard carbon as a negative electrode active material powder, 10% by mass of PVdF as a binder, and mixed with a mixer. Further, an appropriate amount of N-methyl-2-pyrrolidone (NMP) was added as a solvent so that the viscosity was 7000 cP, and the mixture was vacuum-mixed to prepare a slurry.

(Coating, pressing)
Using the negative electrode slurry prepared as described above, first, the negative electrode slurry was applied by patterning on a copper current collector (process 1: 120 × 120 mm, process 2: 120 × 150 mm) in a 10 cm square, and dried. It was heated and dried at about 80 ° C. with a machine. Further, pressing was performed so that the negative electrode electrode porosity was 40%.

  Using the positive electrode slurry prepared as described above, an aluminum current collector (process 1: 120 × 120 mm, process 2: 120 × 120 mm) was coated with a 9 cm square pattern using an applicator, and then dried at 80 ° C. with a dryer. Heated to dryness. Further, pressing was performed so that the positive electrode porosity was 40%.

Production of separator (2)
For the separator using a PP nonwoven fabric (porosity: about 50%) having a thickness of about 12 μm as a separator, a copolymer of polyethylene oxide and polypropylene oxide (having a weight average molecular weight of 8000) was used as a host polymer. ), A lithium salt LiBF ₄ dissolved in electrolyte solution EC + DM at 1.0 M, and a pregel solution composed of AIBN as a polymerization initiator are immersed and thermally polymerized at 90 ° C. for 1 hour in an inert atmosphere. Thus, a gel electrolyte layer formed by holding the gel electrolyte on the nonwoven fabric separator was formed. The thickness of the obtained gel electrolyte layer was about 30 μm.

Production of battery of process 1 (comparative example) (3)
The electrode used in the above process 1 (copper current collector (process 1: 120 × 120 mm)), the gel electrolyte layer that is also a separator, and the gel electrolyte layer and the sealing material (polypropylene) in which the positive electrode and the negative electrode are also separators are sandwiched A single cell of process 1 was fabricated with a simple configuration.

Production of battery of process 2 (Example according to the present invention) (4)
The electrode used in the above process 2 (copper current collector (process 2: 120 × 150 mm)), the gel electrolyte layer that is also a separator, and the gel electrolyte layer and the sealing material (polypropylene) in which the positive electrode and the negative electrode are also separators are sandwiched A single cell of process 2 was fabricated with a simple configuration. Using the electrodes prepared as described above, batteries were prepared by the methods of Process 1 (conventional manufacturing method) and 2 (manufacturing method according to the present invention), and resistance and rate characteristics were evaluated. Table 1 shows the results.

(Discharge capacity measurement)
The produced battery was charged with a constant current and a constant voltage up to 4.20V. The current value at this time was 1 C, and the time was 4 hours. After charging, constant current discharging was performed up to 2.50 V with a discharging current of 1C. The discharge capacity at this time was defined as the discharge capacity of each battery.

(Resistance measurement)
Adjust the battery voltage to 50% SOC, and discharge from the voltage with discharge current of 1C (unit time rate load), 2C (0.5 hour rate negative), 3C (1/3 time rate load). The voltage after 10 seconds from the start of discharge was measured. The resistance was measured from the measured voltage drop.

(10C rate measurement)
The produced battery was charged with a constant current and a constant voltage up to 4.20V. At this time, the current value was 1 C, and the time was 4 hours. After charging, the battery was discharged to 2.50 V at a constant current discharge rate of 10C. The ratio of the discharge capacity obtained at this time to the 1C discharge capacity was defined as a 10C rate characteristic.

  The values in Table 1 below are based on Process 1 (prior art) as 100%.

  The battery produced by the method of process 1 had a lower resistance than process 2 and good rate characteristics. These results seem to be because the gas existing between the electrodes is removed and the distance between the electrodes is in an ideal state by degassing in the process 2. In Process 1, since the gas remains between the electrodes, the distance between the electrodes increases, and it is considered that the battery has high resistance and poor rate characteristics.

It is explanatory drawing which showed typically the battery element used for the process 1-2 of the manufacturing method which concerns on this invention, and this invention. It is explanatory drawing which showed typically the steps 3-6 of the manufacturing method which concerns on this invention. It is explanatory drawing which showed typically the processes 7-9 of the manufacturing method which concerns on this invention.

Explanation of symbols

1 ... current collector (a),
2 ... current collector (b),
3 ... Separator,
4 ... positive electrode layer,
5 ... negative electrode layer,
6 ... sealing material,
7 ... protruding portion protruding outside,
8: The maximum distance between the outer circumference and the inner circumference,
9: Positive electrode,
10 ... negative electrode,
11: Maximum distance between the outer periphery and the inner periphery.

Claims (5)

In a method for producing a secondary battery in which a current collector provided with a positive electrode active material and a negative electrode active material and a separator are laminated,
Step (I) of forming a positive electrode active material layer on one surface of the current collector (a) so that the bonding region is formed with substantially the same width over the entire circumference to obtain a positive electrode laminate;
The negative electrode active material layer is formed on one surface of the current collector (b) so that the bonding region is formed with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. Forming a negative electrode laminate (II);
A larger sealing material than the negative electrode laminate obtained in the step (II), and a separator comprising the negative electrode laminate obtained in the step (II) and the positive electrode laminate obtained in the step (I). Step (III) of forming a laminated body having an open end by sealing so as to open the protrusion after being sandwiched between them;
Step (IV) of sealing the open end after injecting an electrolyte from the open end;
Step (V) of charging the laminate obtained in the step (IV), cutting the projecting portion, forming an open end portion again, and degassing;
Step (VI) of sealing again the open end of Step (V)
The manufacturing method of the secondary battery which has these. In a method for producing a secondary battery in which a current collector provided with a positive electrode active material and a negative electrode active material and a separator are laminated,
Step (I) of forming a negative electrode active material layer on one side of the current collector (a) so that the bonding region is formed with substantially the same width over the entire circumference to obtain a negative electrode laminate;
The positive electrode active material layer is formed on one surface of the current collector (b) so that the bonding region is formed with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. Forming a positive electrode laminate (II);
A larger sealing material than the negative electrode laminate obtained in the step (II), and a separator comprising the negative electrode laminate obtained in the step (II) and the positive electrode laminate obtained in the step (I). Step (III) of forming a laminated body having an open end by sealing so as to open the protrusion after being sandwiched between them;
Step (IV) of sealing the open end after injecting an electrolyte from the open end;
Step (V) of charging the laminate obtained in the step (IV), cutting the projecting portion, forming an open end portion again, and degassing;
Step (VI) of sealing again the open end of Step (V)
The manufacturing method of the secondary battery which has these. In a method for producing a secondary battery in which a current collector provided with a positive electrode active material and a negative electrode active material and a separator are laminated,
A positive electrode active material layer is formed on one surface of the current collector (a) so that the bonding regions are formed with substantially the same width over the entire circumference, and the negative electrode active material is symmetrical to the positive electrode active material layer on the other surface. Forming a layer of material to obtain an electrode laminate (A) (I);
The negative electrode active material layer is formed on one surface of the current collector (b) so that the bonding region is formed with substantially the same width over the entire circumference and a part of the bonding region protrudes outward. In addition, a positive electrode active material layer is formed on the other surface so as to be symmetrical to the negative electrode active material layer, and a part of the bonding region protrudes outward. Step (II) for obtaining a laminate (B);
A sealing material larger than the electrode laminate (B) obtained in the step (II) and a separator were obtained in the electrode laminate (A) obtained in the step (I) and the step (II). Step (III) of forming a laminate having an open end by sealing between the electrode laminate (B) and then sealing the projecting portion to be open;
Step (IV) of sealing the open end after injecting an electrolyte from the open end;
Step (V) of charging the laminate obtained in the step (IV), cutting the projecting portion, forming an open end portion again, and degassing;
Step (VI) of sealing again the open end of Step (V)
A method for manufacturing a bipolar secondary battery.   The battery obtained by the manufacturing method of Claims 1-3.   A battery module according to claim 3, wherein the battery according to claim 3 is connected in series, in parallel, or in a mixture of series and parallel.