JP2016122495A - Battery manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery manufacturing method that can secure sufficient seal strength even when electrolytic solution adheres to a heat seal planned site in a heat seal operation of an exterior packaging material after electrolytic solution is injected.SOLUTION: A manufacturing method comprises: a step of preparing a temporary seal member 30 in which a battery main body portion 23 is disposed in a bag body having a substantially rectangular shape in plan view, three sides out of four sides in the neighborhood of the surrounding of the battery main body portion in the bag body being blocked, and one residual side portion 34 being subjected to heat seal joints 25, 26 while a non-seal opening portion 24 is left at a part in the length direction of the one side portion 34; an injection step of disposing the temporary seal member while the temporary seal member is erected with the non-sealing opening portion 24 being opened upwards, disposing the tip of an electrolytic solution injecting nozzle 40 just above the non-seal opening portion 24 or inserting the electrolytic liquid solution injecting nozzle 40 into the non-seal opening portion 24 and injecting electrolytic solution into the battery main body portion 23; and a sealing step of heat-sealing the non-seal opening portion 24 of the temporary seal member 30 after the injection step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a laminated secondary battery such as a laminated lithium ion secondary battery laminated with an exterior material.

  In recent years, as mobile electrical devices such as smartphones and tablet terminals have become thinner and lighter, power storage devices such as lithium-ion secondary batteries, lithium-polymer secondary batteries, lithium-ion capacitors, and electric double-layer capacitors that are installed in these devices have been reduced. As the exterior material, a laminate composed of a heat-resistant resin layer / adhesive layer / metal foil layer / adhesive layer / thermoplastic resin layer (inner layer) is used instead of a conventional metal can.

  For example, the battery body 123 is disposed between an exterior material front surface portion 121 and an exterior material rear surface portion formed by folding the exterior material into two with the inner layer inside, and the bent side portion 131 and the opposed side seal portion 135 and a lower seal portion 136 are formed to seal the temporary seal member 130 (see FIG. 6A), and the electrolyte injection nozzle 140 is inserted from the upper end opening of the temporary seal member 130. Then, the electrolytic solution is injected into the battery body 123 using the electrolytic solution injection nozzle 140 (see FIG. 6B), and then the upper end opening of the gas chamber 141 is heat-sealed to heat the upper end seal portion 137 of the gas chamber. (See FIG. 6C), and thereafter, a chemical conversion treatment is performed (see FIG. 7A). The gas chamber 141 is for securing a space for storing gas because gas is generated during the chemical conversion treatment. After the chemical conversion treatment, while degassing from the gas chamber 141, the second adjacent side portion 134 of the temporary seal member 130 is finally heat sealed to form the second adjacent side seal portion 127 to complete the sealing (FIG. 7 ( B)), and finally, a portion (substantially upper half) corresponding to the gas chamber 141 is removed by trimming, whereby the laminated battery 110 can be manufactured (see FIG. 7C).

  Moreover, the following heat sealing methods are known. That is, a lithium battery formed by a flexible exterior material that houses a lithium battery main body and has an opening in a part thereof, in which at least a base material layer, an aluminum foil, a chemical conversion treatment layer, and an inner layer made of a heat-adhesive resin are sequentially laminated. A method of heat sealing the opening of the exterior body, the first step of heating and drying a portion to be a heat sealing portion of the opening at a temperature lower than the melting point of the thermoadhesive resin forming the inner layer, A heat sealing method for a lithium battery exterior body is known which includes a second step of heat-sealing a portion to be a heat-sealing portion of an opening by heat-bonding by a heat-bonding means (see Patent Document 1).

JP 2006-261103 A

  However, according to the former sealing method shown in FIGS. 6 and 7, the electrolytic solution adheres to the inner surface of the final heat seal scheduled portion (second adjacent side portion) 134 of the temporary seal member 130 by the injection operation of the electrolytic solution. Therefore, heat sealing is performed by interposing such electrolyte contaminants, so that sufficient sealing strength cannot be ensured, and there is a concern that delamination may occur at the heat sealing location. The

  Further, in the latter sealing method, since the electrolytic solution adheres to the entire area of the final heat seal planned portion, there is a problem that it takes time to heat and dry and the productivity is inferior. In particular, since the attached electrolytic solution is heated and dried at a temperature lower than the melting point of the thermoadhesive resin forming the inner layer, it takes a considerable time to heat and dry.

  The present invention has been made in view of such a technical background, and has sufficient sealing strength even when an electrolyte is attached to a heat-seal planned site during heat sealing of an exterior material after injection of the electrolyte. An object of the present invention is to provide a method for producing a battery that can be ensured and can prevent the occurrence of delamination at a heat-sealed portion and is excellent in productivity.

  In order to achieve the above object, the present invention provides the following means.

[1] A bag having a substantially rectangular shape in a plan view formed of an exterior material including a heat-resistant resin layer as an outer layer, a thermoplastic resin layer as an inner layer, and a metal foil layer disposed between the two layers. A battery main body is disposed inside the body, and three of the four sides of the bag body in the vicinity of the periphery of the battery main body are sealed, and the remaining one side is not sealed in a part of its length direction. Preparing a temporary seal member that is heat-sealed and leaving an opening; and
The temporary seal member is disposed in a standing state with the unsealed opening opened upward, and the tip of the electrolyte injection nozzle is disposed at a position immediately above the unsealed opening or the unsealed opening An injection step of injecting an electrolyte solution into the battery main body by inserting it into the part,
A method for producing a battery, comprising: an encapsulating step of heat-sealing an unsealed opening in the temporary seal member after the injecting step.

  [2] The temporary seal member according to the preceding item 1, wherein the remaining one side portion is formed by heat sealing joining at both ends in the length direction while leaving an unsealed opening in a part of the length direction. Battery manufacturing method.

  [3] In the enclosing step, the heat sealing is performed using a pair of heat sealing bars in which an inner contact surface is formed in a curved shape in which a center part in the length direction and / or width direction of the heat sealing bar protrudes. 3. The method for producing a battery according to 1 or 2 above, wherein bonding is performed.

  [4] The method for manufacturing a battery according to any one of items 1 to 3, wherein, in the enclosing step, the heat seal bonding is performed using a pair of heat seal bars in which a porous sheet is disposed on an inner contact surface.

  [5] Of the three sides sealed in the temporary seal member, one side is sealed by a bent portion formed by folding the exterior material into two with the inner layer as the inner side. 5. The method for producing a battery according to any one of items 1 to 4.

  In the invention of [1], in the stage before the injection step of injecting the electrolytic solution, the remaining one side portion is heat-sealed with the remaining portion in the length direction leaving an unsealed opening in a part of the length direction. As a result, the injection port (unsealed opening) for injecting the electrolyte is small, and this reduces the amount of residual adhered electrolyte in the planned sealing portion (unsealed opening) after the injection of the electrolyte. Therefore, the residual adhered electrolyte is likely to evaporate during heat sealing (the residual adhered electrolyte can be quickly volatilized by the heat during heat sealing due to the small amount of the residual adhered electrolyte), and the heat is good. Seal bonding can be realized (a sufficient seal strength can be secured), and delamination of the seal portion can be prevented.

  Thus, since the quality and reliability of the seal portion can be improved, it contributes to productivity improvement (yield improvement, inspection frequency reduction, etc.) and battery quality improvement (battery life extension, reliability improvement, etc.).

  In addition, since the injection port (unsealed opening) for injecting the electrolyte becomes small, it is possible to suppress the electrolyte scattering during the electrolyte injection and the electrolyte scattering during the degassing seal. Further, it is possible to minimize the adhesion of the electrolytic solution at the planned sealing portion (unsealed opening). As a result, the amount of electrolyte solution injection can be managed with high accuracy, and an electrolyte solution contaminated part can be specified, which has the advantage of easy quality control.

  Furthermore, the heat seal portion corresponding to the unsealed opening can obtain the effect that the amount of the residual adhered electrolyte solution is small as described above, while the effect of the electrolyte solution contamination is small, and there is no other electrolyte solution contamination. Since the seal strength is slightly lower than that of the (remaining) heat seal portion, even if the battery is overheated and the internal pressure increases due to the internally generated gas, Since the “heat seal portion corresponding to the opening” becomes a “gas leak portion” for ensuring safety, there is an advantage that the position of the gas leak portion can be clearly set.

  In the invention of [2], since the temporary sealing member is provided with an unsealed opening in an intermediate region that is not an end in the length direction in the remaining one side, the unsealed opening of the electrolyte injection nozzle It is possible to smoothly perform the insertion operation into the part.

  In the inventions of [3] and [4], even if the electrolyte solution adheres to the unsealed opening that is to be heat sealed, heat seal bonding can be performed while escaping the electrolyte solution to the peripheral side. It is possible to realize better heat seal bonding that can secure the above and sufficiently prevent the occurrence of delamination in the seal portion.

  In the invention of [5], in the step of preparing the temporary seal member, one of the three sides that are sealed is not a seal joint, but is a structure that is sealed by a double-folded bent portion. The property can be further improved.

It is a front view explaining the process of the first half of the manufacturing method of this invention, Comprising: (A) is the state which heat-sealed in the both sides part, leaving an unseal | opened opening part in a 2nd adjacent edge part, (B) is unseal | sealed. A state in which an electrolytic solution injection nozzle is inserted into the opening to inject the electrolytic solution, and (C) shows a state in which the opening at the upper end of the gas chamber is heat sealed to form a sealed bag. It is a front view explaining the latter half process of the manufacturing method of this invention, (A) is the state which is making the electrolyte solution osmose | permeate to an electrode material by chemical conversion treatment, (B) is heat seal joining an unsealed opening part. (C) shows a state in which a laminated battery is obtained by removing the gas chamber portion by trimming. It is sectional drawing which shows the state which heat seals an unsealed opening part with a pair of heat seal bar. It is sectional drawing which shows the other example of the state which heat seals an unsealed opening part with a pair of heat seal bar. It is sectional drawing which shows an example of the exterior material used with the manufacturing method of this invention. It is a front view explaining the process of the first half of the conventional manufacturing method, (A) is the state which left the opening part of the upper end of a gas chamber, and the other side was heat-sealed, (B) is the nozzle for electrolyte injection. (C) shows the state which heat-sealed the opening part of the upper end of a gas chamber, and was set as the sealing bag, respectively. It is a front view explaining the latter half process of the conventional manufacturing method, (A) is a state in which the electrolytic solution is infiltrated into the electrode material by chemical conversion treatment, (B) completes sealing by performing final heat sealing (C) shows a state in which the gas chamber is removed by trimming to form a laminated battery.

  A battery manufacturing method according to the present invention will be described with reference to the drawings. As the exterior material 1 used in the manufacturing method of the present invention, a heat-resistant resin layer 2 as an outer layer, a thermoplastic resin layer 3 as an inner layer, and a metal foil layer 4 disposed between these two layers are used. Use the exterior packaging material (see FIG. 5). For example, the heat-resistant resin layer (outer layer) 2 is laminated and integrated on one surface of the metal foil layer 4 via the first adhesive layer 5, and the second adhesive layer is formed on the other surface of the metal foil layer 4. An exterior material 1 in which a thermoplastic resin layer (inner layer) 3 is laminated and integrated through 6 is used (see FIG. 5).

  A battery main body portion 23 is disposed inside a bag body having a substantially rectangular shape in plan view formed of the exterior material 1 having the above configuration, and three sides 31 of four sides in the vicinity of the battery main body portion 23 in the bag body, The temporary side seal member 30 formed by heat-sealing the one side portion 34 that is left while the portions 32 and 33 are sealed, leaving an unsealed opening 24 in a part of the length direction (FIG. 1A). reference).

  In the temporary seal member 30, the substantially rectangular exterior material front surface portion 21 formed by folding the exterior material 1 having a substantially rectangular shape in plan view in an intermediate position in the length direction with the inner layer 3 inside is folded. A battery body portion 23 having a substantially rectangular shape in a plan view is arranged between the rectangular exterior material rear surface portion 22 and the rectangular exterior material rear surface portion 22. In FIG. 1, reference numeral 31 denotes a bent side (folded portion). The battery main body 23 is disposed in a substantially lower half of the space between the exterior material front surface portion 21 and the exterior material rear surface portion 22 (see FIG. 1A). The facing side seal portion 35 is formed by joining the exterior material front surface portion 21 and the exterior material back surface portion 22 by heat sealing or the like at the facing side portion 32 that faces the folded side 31 that is folded in half.

  The positive electrode tab lead 11 and the negative electrode tab lead 12 are extended outward from one side (opposite side portion) 32 of the battery body 23 (see FIG. 1A). Thus, in the present embodiment, in the facing side portion 32, the exterior material front surface portion 21 and the exterior material rear surface portion 22 are joined by heat sealing or the like with the positive electrode tab lead 11 and the negative electrode tab lead 12 sandwiched therebetween. 35 is formed (see FIG. 1A). The tip of the positive electrode tab lead 11 is led out to the outside, and the tip of the negative electrode tab lead 12 is led out to the outside. The battery body 23 includes, as constituent elements, a positive electrode material, a negative electrode material, and an electrolytic solution, but at this stage, the electrolytic solution has not yet been injected. A positive electrode tab lead 11 is connected to the positive electrode material, and a negative electrode tab lead 12 is connected to the negative electrode material.

  Of the four sides 31, 32, 33, 34 in the vicinity of the battery main body 23 in the bag body, the exterior material front surface portion 21 and the exterior material back surface portion 22 in the first adjacent side portion 33 adjacent to the bent side 31. Are joined by heat sealing or the like to form a first adjacent side sealing portion 36 (see FIG. 1A). Of the four sides 31, 32, 33, 34 near the periphery of the battery body 23 in the bag body, the other second adjacent side 34 adjacent to the bent side 31 is not partly in the length direction. Joined by heat sealing or the like, leaving the seal opening 24, the partial seal portion (first partial seal portion) 25 on one end side in the length direction and the other end side in the length direction across the unsealed opening portion 24 The partial seal portion (second partial seal portion) 26 is formed (see FIG. 1A). In FIG. 1, the internal space 41 above the first and second partial seal portions 25 and 26 in the temporary seal member 30 is referred to as a “gas chamber”.

  Next, as shown in FIG. 1 (B), the temporary seal member 30 is arranged in a state where the second adjacent side portion 34 is arranged above the first adjacent side portion 33, that is, the temporary seal member 30 is placed. The seal member 30 is disposed in a state where the unsealed opening 24 is disposed above the first adjacent side seal portion 36 and the tip of the electrolyte injection nozzle 40 is positioned immediately above the unsealed opening 24. As shown in FIG. 1B, the electrolytic solution is injected into the battery main body portion 23 by being inserted into the unsealed opening 24 (injection step).

  Although it does not specifically limit as said electrolyte solution, For example, the density | concentration of 1 mol / L of lithium hexafluorophosphate is with respect to the mixed solvent which mixed ethylene carbonate and diethylene carbonate by the volume ratio of 1: 1. And a solution (electrolytic solution) dissolved so as to be.

  Next, the opening at the upper end of the gas chamber 41 in the temporary seal member 30 is heat-sealed to form the gas chamber upper end seal portion 37 to create a sealed bag (see FIG. 1C).

  The injecting step and the sealed bag making step are preferably performed in a dry room in order to extend the life of the laminated battery by minimizing moisture remaining in the obtained laminated battery. Examples of the conditions in the dry room include a dew point in the range of “−40 ° C.” to “−60 ° C.”.

  Next, the sealing bag (temporary seal member) 30 is placed in the chemical conversion treatment container 50 and subjected to chemical conversion treatment to permeate the electrolyte into the electrode materials (positive electrode material and negative electrode material) (chemical conversion treatment step) (FIG. 2A). )reference). Examples of the chemical conversion treatment include the following treatment. First, after leaving it at room temperature, it is left in an atmosphere of 40 ° C. to 60 ° C. to lower the viscosity of the electrolytic solution and let the electrolytic solution soak into (permeate) the electrode material (electrode active material or the like). ). Next, press depressurization, initial charging, and pressure deaeration in a high temperature (40 ° C. to 60 ° C.) atmosphere are performed from the top surface of the laminated battery equivalent portion.

  Thereafter, while performing degassing (vacuum degassing etc.) inside the sealing bag (temporary sealing member) 30, the unsealed opening 24 of the second adjacent side portion 34 in the sealing bag (temporary sealing member) 30 is formed. Heat seal bonding is performed to form the second adjacent side seal portion 27 and the sealing with the exterior material 1 is completed (encapsulation step) (see FIG. 2B).

  The heat sealing temperature when heat-sealing the unsealed opening 24 is preferably set to a temperature higher than the melting point of the thermoplastic resin constituting the thermoplastic resin layer 3, and the thermoplastic constituting the thermoplastic resin layer 3 is preferable. It is particularly preferable to set the temperature 20 to 40 ° C. higher than the melting point of the resin.

  Next, a portion (substantially upper half) corresponding to the gas chamber 41 in the sealing bag 30 is removed by trimming to obtain a laminated battery 10 shown in FIG. In this laminated battery 10, all four sides 31, 32, 33, and 34 in the vicinity of the periphery of the battery main body portion 23 in the outer package 1 are sealed (see FIG. 2C).

  In the sealing step, when the unsealed opening 24 of the sealing bag (temporary sealing member) 30 is heat sealed, it is preferable to perform heat sealing using a heat seal bar shown in FIGS.

  In the heat seal bar 43 shown in FIG. 3, the inner contact surface 44 is configured in a curved shape in which the center portion in the length direction of the heat seal bar protrudes (the center portion becomes convex). When heat sealing is performed on the unsealed opening 24 of the second adjacent side 34 using the pair of heat seal bars 43 having such a configuration, the electrolyte adheres to the unsealed opening scheduled to be heat sealed. Even in such a case, the heat seal bonding can be performed while the electrolyte is released to the peripheral side, so that high sealing strength can be ensured. The heat seal bar 43 may be configured to have a curved shape in which the center portion in the width direction of the heat seal bar protrudes (the center portion becomes convex). Further, the heat seal bar 43 may be configured in a curved shape in which the center part in the length direction and the width direction of the heat seal bar protrudes (the center part becomes convex). Although it does not specifically limit as said curved shape, For example, circular arc shape etc. are mentioned.

  Further, in the heat seal bar 46 shown in FIG. 4, a porous sheet 48 is disposed on the inner contact surface. In the present embodiment, both end portions of the porous sheet 48 are bonded and fixed to both side surfaces of the heat seal bar 46, respectively. When heat sealing of the unsealed opening 24 of the second adjacent side 34 is performed using the pair of heat seal bars 46 having such a configuration, the electrolyte adheres to the unsealed opening scheduled to be heat sealed. Even in such a case, the heat seal bonding can be performed while the electrolyte is released to the peripheral side, so that high sealing strength can be ensured. The porous sheet 48 is not particularly limited, and examples thereof include a mesh sheet, a glass cloth sheet, a nonwoven fabric sheet, and an embossed sheet. The material of the mesh sheet, the nonwoven fabric sheet and the embossed sheet is not particularly limited. For example, polyester resin, polyimide resin, fluororesin (polytetrafluoroethylene, etc.), glass (glass cloth, etc.) and fluororesin And composite materials (polytetrafluoroethylene, etc.).

  Next, the exterior material 1 used in the production method of the present invention will be described in detail.

  As the heat-resistant resin constituting the heat-resistant resin layer (outer layer) 2, a heat-resistant resin that does not melt at the heat sealing temperature when heat-sealing the exterior material is used. As the heat resistant resin, it is preferable to use a heat resistant resin having a melting point higher by 10 ° C. or higher than the melting point of the thermoplastic resin constituting the thermoplastic resin layer 3, and having a melting point higher by 20 ° C. or higher than the melting point of the thermoplastic resin. It is particularly preferable to use a heat resistant resin.

  The heat-resistant resin layer (outer layer) 2 is not particularly limited, and examples thereof include polyamide films such as nylon films, polyester films, and the like, and these stretched films are preferably used. Among them, the heat-resistant resin layer 2 includes a biaxially stretched polyamide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film or a biaxially stretched polyethylene film. It is particularly preferable to use a phthalate (PEN) film. The nylon film is not particularly limited, and examples thereof include 6 nylon film, 6,6 nylon film, MXD nylon film, and the like. The heat-resistant resin layer 2 may be formed as a single layer, or may be formed as a multilayer composed of a polyester film / polyamide film (such as a multilayer composed of PET film / nylon film). Also good.

  The thickness of the heat resistant resin layer 2 is preferably 5 μm to 80 μm. By setting it above the above preferred lower limit value, it is possible to ensure sufficient strength as an exterior material, and by setting it below the above preferred upper limit value, it is possible to reduce the stress at the time of molding such as stretch forming, draw forming, etc. and improve moldability Can be made.

  The thermoplastic resin layer (inner layer) 3 has excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and provides heat sealability to the exterior material. To play a role.

  Although it does not specifically limit as said thermoplastic resin layer 3, It is preferable that it is a thermoplastic resin unstretched film layer. The thermoplastic resin unstretched film layer 3 is not particularly limited, but is at least one thermoplastic selected from the group consisting of polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers. It is preferably composed of an unstretched film made of a resin.

  The thickness of the thermoplastic resin layer 3 is preferably set to 20 μm to 80 μm. When the thickness is 20 μm or more, pinholes can be sufficiently prevented from being generated, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, and the cost can be reduced. Especially, it is especially preferable that the thickness of the thermoplastic resin layer 3 is set to 30 μm to 50 μm. The thermoplastic resin layer 3 may be a single layer or a multilayer.

  The metal foil layer 4 plays a role of imparting a gas barrier property to the exterior material 1 to prevent entry of oxygen and moisture. Although it does not specifically limit as said metal foil layer 4, For example, aluminum foil, copper foil, SUS foil (stainless steel foil) etc. are mentioned, Aluminum foil and SUS foil are generally used. A material of the aluminum foil is preferably an A8079-O material or an A8021-O material. The thickness of the metal foil layer 4 is preferably 15 μm to 80 μm. When it is 15 μm or more, it can prevent the occurrence of pinholes during rolling when manufacturing a metal foil, and when it is 80 μm or less, it can reduce the stress during forming such as stretch forming and draw forming, thereby improving formability. be able to.

The metal foil layer 4 is preferably subjected to chemical conversion coating on at least the inner surface (the surface on the second adhesive layer 6 side). By performing such a chemical conversion film treatment, corrosion of the surface of the metal foil due to the contents (battery electrolyte or the like) can be sufficiently prevented. For example, a chemical conversion film treatment is performed on the metal foil by performing the following treatment. That is, for example, on the surface of the metal foil after degreasing,
1) phosphoric acid;
Chromic acid,
An aqueous solution of a mixture comprising at least one compound selected from the group consisting of a metal salt of fluoride and a nonmetal salt of fluoride; 2) phosphoric acid;
At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins;
An aqueous solution of a mixture comprising at least one compound selected from the group consisting of chromic acid and a chromium (III) salt, 3) phosphoric acid,
At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins;
At least one compound selected from the group consisting of chromic acid and a chromium (III) salt;
An aqueous solution of a mixture comprising at least one compound selected from the group consisting of a fluoride metal salt and a fluoride non-metal salt. After applying an aqueous solution of any one of the above 1) to 3), drying is performed. By doing so, a chemical conversion coating treatment is performed.

The chemical conversion coating, chromium coating weight preferably is 0.1mg / m ² ~50mg / m ² as a (per one surface), in particular 2mg / m ² ~20mg / m 2 preferred.

  The first adhesive layer 5 is not particularly limited, and examples thereof include a polyurethane adhesive layer, a polyester polyurethane adhesive layer, and a polyether polyurethane adhesive layer. The thickness of the first adhesive layer 5 is preferably set to 1 μm to 5 μm. Especially, it is especially preferable that the thickness of the said 1st adhesive bond layer 5 is set to 1 micrometer-3 micrometers from a viewpoint of thickness reduction of an exterior material and weight reduction.

  Although it does not specifically limit as said 2nd adhesive bond layer 6, For example, what was illustrated as said 1st adhesive bond layer 5 can be used, However, The polyolefin-type adhesive agent with few swelling by electrolyte solution is used. Is preferred. The thickness of the second adhesive layer 6 is preferably set to 1 μm to 5 μm. Especially, it is especially preferable that the thickness of the said 2nd adhesive bond layer 6 is set to 1 micrometer-3 micrometers from a viewpoint of thickness reduction of an exterior material and weight reduction.

  In the manufacturing method of the present invention, the exterior material 1 may be formed in a molded case (a case that can accommodate the battery body 23) by molding (deep drawing molding, stretch molding, etc.). And what is not used for shaping | molding may be used as it is.

  In the above embodiment, the temporary sealing member 30 is configured by folding one exterior material 1 in half. However, the present invention is not particularly limited to this configuration. You may use the temporary seal member 30 comprised so that the mutual inner layer 3 might become an inner surface (so that the mutual inner layer 3 may contact | connect).

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
Applying a chemical conversion coating solution composed of phosphoric acid, polyacrylic acid, trivalent chromium compound, water, alcohol on both sides of an aluminum foil (A8021-O material) 4 having a thickness of 35 μm, and drying at 180 ° C., A conversion coating was formed. The amount of chromium deposited on this chemical conversion film was 10 mg / m ² per side.

  Next, a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 25 μm is provided on one surface of the chemical conversion coating-treated aluminum foil 4 with a two-component curable urethane adhesive (first adhesive layer) 5 interposed therebetween. (Melting point: 230 ° C.) 2 was dry laminated (bonded).

  Next, after applying an adhesive liquid to the other surface of the aluminum foil 4 using a gravure roll, the adhesive resin layer (second adhesive layer) 6 having a thickness of 3 μm is formed by drying with hot air at 80 ° C. Formed. As the adhesive liquid, 15 parts by mass of maleic acid-modified polypropylene (modified polypropylene resin obtained by graft polymerization of maleic anhydride on a copolymer of propylene and ethylene; melting temperature: 80 ° C.) was mixed with a mixed solvent (toluene / methyl ethyl ketone = 8 An adhesive solution obtained by mixing 0.9 part by mass of a polymer of hexamethylene diisocyanate in a solution dissolved in 85 parts by mass of a mixed solvent of 2 parts by mass of 2 parts by mass) was used.

  Next, the surface of the adhesive resin layer 6 formed on the other surface of the aluminum foil 4 has a melting point of 140 ° C. and an MFR (melt flow rate) of 4.5 g / 10 min. By laminating an ethylene random copolymer film (inner layer; sealant layer) 3, an exterior material 1 having the configuration shown in FIG. 5 was obtained.

  A temporary seal member 30 shown in FIG. 1 (A) was prepared using the exterior material 1 by the method detailed in the previous section. In the second adjacent side portion 34 of the temporary seal member 30, 30% of the length is constituted by the partial seal portion 25 on one end side, and 20% of the length is constituted by the unsealed opening 24, and the length thereof. 50% of the total length was constituted by the partial seal portion 26 on the other end side. The seal width of these partial seal portions 25 and 26 was set to 5 mm.

  Next, as shown in FIG. 1B, the tip of the electrolyte injection nozzle 40 was inserted into the unsealed opening 24 to inject the electrolyte into the battery body 23. As an electrolytic solution, a solution (electrolytic solution) obtained by dissolving lithium hexafluorophosphate in a mixed solvent in which ethylene carbonate and diethylene carbonate are mixed at a volume ratio of 1: 1 so as to have a concentration of 1 mol / L. It was used.

  Next, after the upper end opening of the gas chamber 41 is heat-sealed to form the gas chamber upper end seal portion 37 by the method described in detail in the previous section to form a sealed bag (see FIG. 1C), a chemical conversion treatment is performed. (See FIG. 2A). Next, as shown in FIG. 2B, the unsealed opening 24 of the second adjacent side portion 34 is heat sealed (seal width 5 mm) to form a second adjacent side seal portion 27 and sealed. Completed. The heat sealing conditions at this time were 200 ° C. × 0.2 MPa × 6 seconds. As the heat seal bar, a metal seal bar having a fluororesin tape adhered to the surface thereof was used. Next, a portion (substantially upper half) corresponding to the gas chamber 41 was removed by trimming to obtain a laminated battery 10 shown in FIG.

<Comparative Example 1>
A substantially rectangular exterior material front surface portion 121 and a substantially rectangular exterior material rear surface portion formed by folding an exterior material having the same configuration as in Example 1 in an intermediate position in the length direction with the inner layer 3 inside. A battery main body 123 having a substantially rectangular shape in plan view is disposed between the front surface 121 and the rear surface of the exterior material at the opposite side 132 facing the folded side 131 of the fold. 112 is sandwiched by heat sealing to form a facing side seal portion 135, and the exterior material front surface portion 121 and the exterior material back surface portion are heat-sealed at one first adjacent side portion 133 adjacent to the bent side 131. The temporary seal member 130 formed by joining and forming the first adjacent side seal portion 136 is created (see FIG. 6A).

  The temporary sealing member 130 is disposed in a state where the first adjacent side seal portion 136 is placed on the lower side, and the electrolytic solution same as that of the first embodiment is used by using the electrolytic solution injection nozzle 140 inserted from the upper end opening. Was injected into the battery body 123 (see FIG. 6B).

  Next, an opening at the upper end of the gas chamber 141 in the temporary seal member 130 was heat-sealed to form a gas chamber upper end seal portion 137 to constitute a sealing bag (see FIG. 6C). Thereafter, the sealing bag (temporary sealing member) 130 was placed in the chemical conversion treatment container 150 and subjected to chemical conversion treatment, and the electrolytic solution was permeated into the electrode materials (positive electrode material and negative electrode material) (see FIG. 7A).

  Next, while performing degassing (vacuum degassing etc.) inside the sealing bag (temporary sealing member) 130, the second adjacent side portion 134 in the sealing bag (temporary sealing member) 130 is heat-sealed and joined to the second. The adjacent side seal portion 127 was formed, and sealing with the exterior material was completed (see FIG. 7B). Next, a portion (substantially upper half) corresponding to the gas chamber 141 in the sealing bag 130 was removed by trimming to obtain a laminated battery 110 shown in FIG. 7C.

<Reference example>
A temporary seal member 30 shown in FIG. 1 (A) was prepared by using the exterior material 1 having the same configuration as that of Example 1 by the method described in detail in the previous section. In Reference Example 1, the seal strength of the first adjacent side seal portion 36 of the temporary seal member 30 was measured. Since the first adjacent side seal portion 36 is a seal portion that has been heat-sealed before electrolyte injection, the first adjacent-side seal portion 36 is a seal portion that has been heat-sealed without the presence of electrolyte contaminants. With this reference example, it is possible to grasp the seal strength of the seal portion heat-sealed in a state where no electrolyte contaminants are present.

  Each laminated battery obtained as described above was evaluated based on the following evaluation method. The results are shown in Table 1.

<Seal strength evaluation method>
For Example 1, a test piece (15 mm in width) was created so as to include a seal portion corresponding to the unsealed opening 24 from the second adjacent side seal portion 27, and an autograph made by Shimadzu Corporation was used for this test piece. The seal strength (peel strength) of the seal portion was measured at a tensile speed of 100 mm / min. For Comparative Example 1, a test piece (width 15 mm) was prepared from the second adjacent side seal portion 127 as in Example 1, and the seal strength was measured in the same manner. About the reference example, the test piece (15 mm in width) was created from the 1st adjacent edge seal part 36, and seal strength was measured similarly. The seal strength of “50 N / 15 mm width” or more was regarded as acceptable.

<Delamination (peeling) frequency evaluation method>
Ten laminated batteries 10 of Example 1 were prepared, and ten laminated batteries 110 of Comparative Example 1 were prepared. After each laminated battery was allowed to stand at room temperature for 7 days, the presence or absence of delamination (peeling) in the second adjacent side seal portion of each laminated battery was examined. A total of 10 samples were obtained for each of Example 1 and Comparative Example 1. The number of delamination generation samples (batteries) in the (battery) is shown in Table 1.

  As is clear from Table 1, in the laminated battery of Example 1 manufactured by the manufacturing method of the present invention, it was equivalent to the sealing strength of the battery that was heat-sealed without any electrolyte contaminants (Reference Example 1). Sufficient seal strength could be secured. Therefore, in the laminated battery of Example 1, the delamination occurrence frequency was 0/10.

  On the other hand, in the laminate battery of Comparative Example 1 manufactured by the conventional manufacturing method, sufficient seal strength was not obtained, and the frequency of delamination occurrence was 8/10.

  The method for producing a battery according to the present invention is suitable as a method for producing a laminate type secondary battery such as a laminated lithium ion secondary battery, but is not particularly limited to application to such a use.

1 ... exterior material 2 ... heat-resistant resin layer (outer layer)
3 ... Thermoplastic resin layer (inner layer)
4 ... Metal foil layer 10 ... Battery 21 ... Exterior material front surface portion 22 ... Exterior material rear surface portion 23 ... Battery body portion 24 ... Unsealed opening 25 ... One partial seal portion (first partial seal portion)
26 ... The other partial seal part (second partial seal part)
27 ... Second adjacent side seal portion 30 ... Temporary seal member 31 ... Bending side (bending portion)
32 ... Opposite side 33 ... 1st adjacent side 34 ... 2nd adjacent side 35 ... Opposite side seal part 36 ... 1st adjacent side seal part 40 ... Nozzle 43 for electrolyte solution injection ... Heat seal bar 44 ... Contact surface 46 ... heat seal bar 48 ... perforated sheet

Claims (5)

The inside of a bag having a substantially rectangular shape in plan view formed of an exterior material including a heat-resistant resin layer as an outer layer, a thermoplastic resin layer as an inner layer, and a metal foil layer disposed between the two layers. The battery body portion is arranged, three of the four sides of the bag body in the vicinity of the periphery of the battery body portion are sealed, and the remaining one side portion has an unsealed opening in a part of its length direction. A step of preparing a temporary seal member to be heat-sealed and left;
The temporary seal member is disposed in a standing state with the unsealed opening opened upward, and the tip of the electrolyte injection nozzle is disposed at a position immediately above the unsealed opening or the unsealed opening An injection step of injecting an electrolyte solution into the battery main body by inserting it into the part,
A method for producing a battery, comprising: an encapsulating step of heat-sealing an unsealed opening in the temporary seal member after the injecting step.   2. The battery according to claim 1, wherein the temporary seal member is formed by heat-sealing both end sides in the length direction while leaving an unsealed opening in a part in the length direction in the remaining one side portion. Manufacturing method.   In the enclosing step, the heat seal bonding is performed using a pair of heat seal bars in which the inner contact surface is configured in a curved shape in which the center part in the length direction and / or the width direction of the heat seal bar protrudes. The method for producing a battery according to claim 1 or 2.   The manufacturing method of the battery according to any one of claims 1 to 3, wherein in the enclosing step, the heat seal bonding is performed using a pair of heat seal bars in which a porous sheet is disposed on an inner contact surface.   2. One of the three sides sealed in the temporary sealing member is sealed by a bent portion formed by folding the exterior material into two with the inner layer inside. The manufacturing method of the battery of any one of -4.

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