JP2011003294A - Battery pack, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack having both high dimensional accuracy and mechanical strength, and also materializing a small size as well as a light weight.SOLUTION: This battery pack 1 includes: a battery 20 formed by packing up a battery element 10 composed of a positive electrode 11, a negative electrode 12 and separators 12a, 13a with a packaging body 17; the protection circuit board 2 of the battery 20; and an exterior package 3 to integrally cover the battery 20 and the protection circuit board 2 with the terminal of the battery led out from the battery 20 by filling a resin in the molding space of the molding die in which the battery 20 and the protection circuit board 2 are housed to be cured. The exterior package 3 includes a primary exterior package part 3A to partially cover the battery 20 and the protection circuit board 2, and at least one secondary exterior package part 3B to partially cover the battery 20 and the protection circuit board 2, and all exterior package parts 3A, 3B are integrated. Thereby, the battery pack has both dimensional accuracy and mechanical strength and also materializes a small size as well as a light weight.

Description

    The present invention relates to a battery pack including, for example, a non-aqueous electrolyte secondary battery and a method for manufacturing the same. The present invention relates to a battery pack in which a packaged battery and its protection circuit board are integrated, and a method for manufacturing the same.

  In recent years, a large number of portable electronic devices such as camera-integrated video tape recorders, mobile phones, and portable computers have appeared, and their size and weight have been reduced. With the reduction in size and weight of such electronic devices, battery packs used as portable power sources are also required to have high energy and be reduced in size and weight. As a battery used for such a battery pack, there is a lithium ion secondary battery having a high capacity.

  A lithium ion secondary battery includes a battery element having a positive electrode and a negative electrode that can be doped and dedoped with lithium ions. The battery element is enclosed in a metal can or a metal laminate film and electrically connected to the battery element. The circuit board is controlled. Moreover, some conventional lithium ion secondary batteries have a battery pack that is housed together with a circuit board in a housing case that is divided into two vertically (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 3556875 Japanese Patent No. 3614767 Japanese Patent No. 3643792

  By the way, in the conventional lithium ion secondary battery as described above, when a metal can is used to enclose the battery element, high dimensional accuracy is easily secured, but the thickness and weight are slightly increased. On the other hand, using a metal laminate film to enclose a battery element is thinner and lighter than a metal can, but it is difficult to increase dimensional accuracy due to large variations in the dimensions of the battery element, as well as mechanical strength. Has the disadvantage of being low.

  In addition, in a conventional battery pack in which a lithium ion secondary battery and a circuit board are stored in a storage case, the storage case is sufficient to protect the lithium ion secondary battery and the circuit board from external shocks. In addition, when the storage case divided into upper and lower parts is joined by double-sided tape or ultrasonic welding, it is necessary to secure a sufficient thickness in the storage case so as to be able to cope with them. As a result, the thickness and weight of the entire battery pack increase, which is not preferable as a portable power source.

  The present invention has been made paying attention to the above-described conventional problems, and provides a battery pack that has both high dimensional accuracy and mechanical strength, as well as reduced size and weight, and a method for manufacturing the same. It is aimed.

  The battery pack of the present invention contains a battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed between them, a protective circuit board for the battery, and the battery and the protective circuit board. A battery pack including an exterior material that integrally covers the battery and the protection circuit board in a state in which the terminals of the battery are led out to the outside by filling a resin in the molding space of the mold and curing the mold, The exterior material includes a primary exterior part that partially covers the battery and the protection circuit board, and at least one secondary exterior part that partially covers the battery and the protection circuit board, and the entire exterior part is integrated. The above structure is used as means for solving the conventional problems.

  In addition, the battery pack manufacturing method of the present invention includes a battery in which a battery element formed by winding or stacking a positive electrode and a negative electrode with a separator interposed between them, a protective circuit board for the battery, the battery, A battery having an exterior material that integrally covers the battery and the protection circuit board in a state where the terminals of the battery are led out to the outside by filling the resin in the molding space of the molding die containing the protection circuit board and curing the resin. When manufacturing a pack, after forming a primary exterior part having a positioning part of the battery and a protection circuit board as a part of the exterior material, and arranging the battery and the protection circuit board in the positioning part of the primary exterior part, Forming the exterior material by integrating all the exterior parts by forming at least one secondary exterior part to be the remaining part of the exterior material with respect to the primary exterior part, the battery, and the protection circuit board. It is a symptom.

  Furthermore, the battery pack manufacturing method of the present invention includes a battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed between them, a protective circuit board for the battery, the battery, A battery having an exterior material that integrally covers the battery and the protection circuit board in a state where the terminals of the battery are led out to the outside by filling the resin in the molding space of the molding die containing the protection circuit board and curing the resin. When manufacturing a pack, a molding die having a positioning part for the battery and the protection circuit board is used, the battery and the protection circuit board are arranged in the molding die, and a part of the outer packaging material is disposed on the battery and the protection circuit board. A primary exterior part is formed, and then, for the primary exterior part, the battery, and the protective circuit board, at least one secondary exterior part that becomes the remaining part of the exterior material is formed, so that the entire exterior part is integrated. Turn into It is characterized by forming the outer package.

  Here, in order to fill the molding material with a particularly high viscosity as the packaging material, the packaging material is filled with a certain amount of pressure so that no gap is formed in the molding space. At this time, it is necessary to prevent the battery and the protection circuit board from moving from a predetermined position in the molding space by the exterior material to be pressurized and filled, for example, a measure such as providing a positioning projection on the molding die was considered. However, in this case, after the exterior material is cured, there are obstacles such as the recesses due to the positioning protrusions deteriorating the design or becoming difficult for the user to use.

  In the present invention, when the exterior material is filled in the molding space of the mold, the battery and the protection circuit board can be accurately positioned at predetermined positions. A strong exterior material layer will be formed.

  In addition, by increasing or decreasing the filling amount of the packaging material, the dimensional variation inevitable in the manufacture of the battery in which the battery element is packaged in the package can be absorbed by the entire surface of the battery. The pack can be supplied stably.

  Furthermore, in the manufacturing method, when the exterior material is divided into a plurality of exterior parts, a conventional process using a thermoplastic resin is performed through a step of forming an exterior capable of accommodating the battery and the protection circuit board. The positioning jig required for mold packs is no longer required. In addition, since the same mold can be used as a part of the mold even if molding is performed multiple times, the mold cost is reduced and the mold release from the lower mold is not required except for the final molding process. There is an advantage that the production time is shortened and the conveyance is easy.

  Furthermore, in the manufacturing method, the exterior material is divided into a plurality of exterior parts, so that a weld line that is a seam between the exterior parts is formed on the surface of the exterior material. However, as a product, a conventional thermoplastic resin is used. In order to have an appearance that is equal to or better than the mold resin that has been molded in two parts and then encapsulated with battery elements and ultrasonically welded, not only a seal is affixed to the surface of the exterior material, but also printing directly with a laser etc. The design of the battery pack is not impaired, and the capacity and cost can be reduced.

Furthermore, in the present invention, the battery and the protection circuit board are integrally covered with the exterior material, so that the hard cover that has been conventionally required is abolished, and in addition to improving the mechanical strength, further miniaturization is achieved. Weight reduction can also be realized.

  According to the battery pack and the manufacturing method thereof of the present invention, by adopting the above-described configuration, it is possible to provide a battery pack that achieves both high dimensional accuracy and mechanical strength, as well as reduced size and weight. The battery pack can be provided with excellent productivity.

It is side sectional drawing (a) and top sectional drawing (b) explaining one Embodiment of a battery pack. It is a disassembled perspective view explaining the battery before coat | covering with an exterior material. It is a perspective view explaining a battery element. It is end surface explanatory drawing (a) (b) which shows the point which bends the side sealing part of a battery. It is each sectional drawing (a)-(d) explaining 1st Embodiment of the manufacturing method of a battery pack. It is each sectional drawing (a)-(d) explaining 2nd Embodiment of the manufacturing method of a battery pack. It is each sectional drawing (a)-(f) explaining 3rd Embodiment of the manufacturing method of a battery pack. FIG. 8 is a cross-sectional view (a) to (c) illustrating a third embodiment of the battery pack manufacturing method following FIG. 7. It is explanatory drawing which shows the battery pack manufactured by 3rd Embodiment. It is the perspective view (a) which shows an example of a positioning component, and each sectional drawing (b) (c). It is explanatory drawing which shows the other example of the positioning component. It is side sectional drawing (a) and front sectional drawing (b) which show other examples of positioning components. It is side sectional drawing (a) and front sectional drawing (b) which show other examples of positioning components.

  Hereinafter, the battery pack and the manufacturing method thereof of the present invention will be described in detail. In the present specification, “%” for concentration, content, filling amount, and the like represents a mass percentage unless otherwise specified.

<One Embodiment of Battery Pack>
The battery pack of the present invention contains a battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed between them, a protective circuit board for the battery, and the battery and the protective circuit board. The battery is provided with an exterior material that integrally covers the battery and the protection circuit board in a state where the terminals of the battery are led out to the outside by filling the resin in the molding space of the mold and curing it. In the battery pack, the exterior material includes a primary exterior part that partially covers the battery and the protection circuit board, and at least one secondary exterior part that partially covers the battery and the protection circuit board. All the exterior parts are integrated.

  That is, the battery pack 1 shown in FIG. 1 includes a laminate film, which is a package, in which a battery element 10 is formed by winding or laminating a positive electrode 11 and a negative electrode 12 via separators 13a and 13b as shown in FIGS. The polymer-type non-aqueous electrolyte secondary battery 20 packaged in 17 and the protective circuit board 2 of the battery 20 are integrally covered with an exterior material 3.

  At this time, as will be described in detail later, the exterior material 3 is a primary exterior 3A piece that covers one side of the battery 20 and the protection circuit board 2, and a secondary exterior part 3B that covers the remaining side of the battery 20 and the protection circuit board 2. And the exterior parts 3A and 3B are integrated. The joint (interface) between the two exterior portions 3A and 3B becomes a weld line WL. The exterior material 3 integrally covers the battery 20 and the protection circuit board 2 with the terminals 15a and 15b of the battery 20 being led out to the outside. The illustrated battery pack 1 has a flat plate shape, and a buffer material 4 for protecting the protective circuit board 2 and the battery 20 on the top side on the left side in FIG. , 5 are buried.

  As shown in FIG. 2, the battery 20 accommodates the battery element 10 in a rectangular plate-shaped recess 17a formed in a laminate film 17 as a package, and heats the periphery (three sides excluding the bent portion). Then, as shown in FIG. 4, the side portions 17b on both sides of the concave portion 17a accommodating the battery element 10 are bent toward the concave portion 17a.

  As shown in FIG. 3, the battery element 10 includes a strip-shaped positive electrode 11, a separator 13 a, a strip-shaped negative electrode 12 disposed so as to face the positive electrode 11, and a separator 13 b in order, and wound in the longitudinal direction. The gel electrolyte 14 is applied to both surfaces of the positive electrode 11 and the negative electrode 12.

  From this battery element 10, a positive electrode terminal 15a connected to the positive electrode 11 and a negative electrode terminal 15b connected to the negative electrode 12 are derived (hereinafter referred to as an electrode terminal 15 when a specific terminal is not designated), and the positive electrode terminal 15a. The negative electrode terminal 15b has sealants 16a and 16b (hereinafter referred to as specific parts), which are resin pieces such as polypropylene (PPa) modified with maleic anhydride, in order to improve adhesion to the laminate film 17 which will be wrapped later. When the sealant is not designated, it is appropriately referred to as sealant 16).

Hereinafter, the components of the battery element 10 and the battery 20 described above will be described in detail.
[Positive electrode]
The positive electrode 11 is formed by forming a positive electrode active material layer containing a positive electrode active material on both sides of a positive electrode current collector. The positive electrode current collector is composed of a metal foil such as an aluminum (Al) foil, while the positive electrode active material layer is composed of, for example, a positive electrode active material, a conductive agent, and a binder. . Here, the positive electrode active material, the conductive agent, the binder, and the solvent only need to be uniformly dispersed, and the mixing ratio is not limited.

As the positive electrode active material, a metal oxide, a metal sulfide, or a specific polymer can be used depending on the type of the target battery. For example, when a lithium ion battery is configured, the following formula (1) is mainly used.
LiXMO ₂ (1)
(Wherein M represents at least one transition metal, and X varies depending on the charge / discharge state of the battery, but is usually 0.05 to 1.10.) Can be used. Note that cobalt (Co), nickel (Ni), manganese (Mn), or the like can be used as the transition metal (M) constituting the lithium composite oxide.

Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _4, and LiNiyCo _1-y O ₂ (0 <y <1). In addition, a solid solution in which a part of the transition metal element is substituted with another element can be used, and examples thereof include LiNi _0.5 Co _0.5 O ₂ and LiNi _0.8 Co _0.2 O _2. Can do. These lithium composite oxides can generate a high voltage and have an excellent energy density. Furthermore, _{TiS 2,} MoS 2, may be used NbSe no lithium metal sulfides such as ₂ and _V 2 _{O 5} or the oxide as a cathode active material. These positive electrode active materials may be used alone or in admixture of a plurality of types.

  In addition, as the conductive agent, for example, a carbon material such as carbon black or graphite can be used. Furthermore, as the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride, or the like can be used. Moreover, as a solvent, N-methylpyrrolidone (NMP) etc. can be used, for example.

  The above-described positive electrode active material, binder and conductive agent are uniformly mixed to form a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent to form a slurry. Next, the slurry is uniformly applied on the positive electrode current collector by a doctor blade method or the like, and then dried at a high temperature to evaporate the solvent and press to form a positive electrode active material layer.

  The positive electrode 11 has a positive electrode terminal 15a connected to one end of the positive electrode current collector by spot welding or ultrasonic welding. The positive electrode terminal 15a is preferably a metal foil or a mesh-like one, but there is no problem even if it is not a metal as long as it is electrochemically and chemically stable and can be energized. Examples of the material of the positive electrode terminal 15a include aluminum.

[Negative electrode]
The negative electrode 12 is formed by forming a negative electrode active material layer containing a negative electrode active material on both surfaces of a negative electrode current collector. The negative electrode current collector is composed of a metal foil such as a copper (Cu) foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer includes, for example, a negative electrode active material, a conductive agent as necessary, and a binder. In addition, about a negative electrode active material, a electrically conductive agent, a binder, and a solvent, the mixing ratio is not ask | required similarly to a positive electrode active material.

As the negative electrode active material, lithium metal, a lithium alloy, a carbon material that can be doped / undoped with lithium, or a composite material of a metal-based material and a carbon-based material can be used. Specific examples of carbon materials that can be doped / undoped with lithium include graphite, non-graphitizable carbon, and graphitizable carbon. More specifically, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (phenolic resin, furan resin, etc.) at an appropriate temperature. Carbon materials such as those obtained by firing and carbonization), carbon fibers, and activated carbon can be used. Furthermore, as a material that can be doped / undoped with lithium, polymers such as polyacetylene and polypyrrole, and oxides such as SnO ₂ can be used.

  As materials capable of alloying lithium, various kinds of metals can be used, but tin (Sn), cobalt (Co), indium (In), aluminum, silicon (Si), and alloys thereof. Is often used. When metal lithium is used, it is not always necessary to use powder as a coating film with a binder, and a rolled lithium metal foil may be pressure-bonded to a current collector.

  As the binder, for example, polyvinylidene fluoride, styrene butadiene rubber, or the like can be used. Moreover, as a solvent, N-methylpyrrolidone, methyl ethyl ketone, etc. can be used, for example.

  The above-described negative electrode active material, binder, and conductive agent are uniformly mixed to form a negative electrode mixture, which is dispersed in a solvent to form a slurry. Subsequently, after apply | coating uniformly on a negative electrode electrical power collector by the method similar to the positive electrode 11, it is made to dry at high temperature, a solvent is scattered, and a negative electrode active material layer is formed by pressing.

  Similarly to the positive electrode 11, the negative electrode 12 has a negative electrode terminal 15b connected to one end of the current collector by spot welding or ultrasonic welding, and the negative electrode terminal 15b is electrochemically and chemically stable. There is no problem even if it is not metal if it can be energized. Examples of the material of the negative electrode terminal 15b include copper and nickel.

  In addition, as described above, when the battery element 10 has a rectangular plate shape, the positive electrode terminal 15a and the negative electrode terminal 15b are preferably led out from one side (usually one of the short sides) in the same direction. As long as no short circuit occurs and the battery performance is not a problem, there is no problem even if it is derived from any direction. Moreover, as long as the electrical connection is taken for the connection place of the positive electrode terminals 15a and 15b, the attachment place and the attachment method are not limited to the above example.

[Electrolyte]
As the electrolytic solution, an electrolyte salt and a non-aqueous solvent that are generally used in lithium ion batteries can be used.

  Specific examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate and ethylpropyl carbonate, or hydrogen of these carbonic acid esters to halogen. There are substituted solvents and the like. One of these solvents may be used alone, or a plurality of these solvents may be mixed and used in a predetermined composition.

Moreover, as lithium salt which is an example of electrolyte salt, it is possible to use the material used for normal battery electrolyte solution. Specifically, LiCl, LiBr, LiI, LiClO ₃ , LiClO ₄ , LiBF ₄ , LiPF ₆ , LiNO ₃ , LiN (CF ₃ SO ₂ ) 2, LiN (C ₂ F ₅ SO ₂ ) 2, LiAsF ₆ , LiCF ₃ SO ₃ , LiC (SO ₂ CF ₃ ) 3, LiAlCl _4, LiSiF _{6 and the} like can be mentioned, but LiPF ₆ and LiBF ₄ are preferable from the viewpoint of oxidation stability. These lithium salts may be used alone or in combination of two or more. The concentration for dissolving the lithium salt is not a problem as long as it can be dissolved in the non-aqueous solvent, but the lithium ion concentration is in the range of 0.4 mol / kg to 2.0 mol / kg with respect to the non-aqueous solvent. Preferably there is.

  In the case of using a gel electrolyte, the above-described electrolytic solution is gelled with a matrix polymer. The matrix polymer is not particularly limited as long as it is compatible with a nonaqueous electrolytic solution obtained by dissolving an electrolyte salt in a nonaqueous solvent and can be gelled. Examples of such a matrix polymer include a polymer containing polyvinylidene fluoride, polyethylene oxide, polypropylene oxide, polyacrylonitrile, and polymethacrylonitrile in repeating units. Such a polymer may be used individually by 1 type, and 2 or more types may be mixed and used for it.

Among them, particularly preferable as the matrix polymer is polyvinylidene fluoride or a copolymer in which hexafluoropropylene is introduced into polyvinylidene fluoride at a ratio of 7.5% or less. Such polymers usually have a number average molecular weight in the range of 5.0 × 10 ^{5 to} 7.0 × 10 ⁵ (500,000 to 700,000) or a weight average molecular weight of 2.1 × 10 ^{5 to} 3 0.1 × 10 ⁵ (210,000-310,000) and intrinsic viscosity in the range of 1.7-2.1 dl / g.

[Separator]
Separator 13a, 13b is comprised by the porous film | membrane which consists of inorganic materials, such as the porous material which consists of polyolefin-type materials, such as a polypropylene (PP) or polyethylene (PE), or the nonwoven fabric made from ceramics, for example, A structure in which two or more kinds of porous films are laminated may be employed. Among these, polyethylene and polypropylene porous films are the most effective.

  In general, the thickness of the separators 13a and 13b is preferably 5 to 50 μm, more preferably 7 to 30 μm. If the separators 13a and 13b are too thick, the filling amount of the active material is reduced to lower the battery capacity, and the ionic conductivity is lowered to lower the current characteristics. On the other hand, if the film is too thin, the mechanical strength of the film decreases.

[Production of battery]
The gel electrolyte solution prepared as described above is uniformly applied to the positive electrode 11 and the negative electrode 12 and impregnated in the positive electrode active material layer and the negative electrode active material layer, and then stored at room temperature or subjected to a drying process. A state electrolyte layer 14 is formed.

  Next, using the positive electrode 11 and the negative electrode 12 on which the gel electrolyte layer 14 is formed, the positive electrode 11, the separator 13 a, the negative electrode 12, and the separator 13 b are stacked in this order, and then wound to form the battery element 10. 10 is accommodated in the recess 17a of the laminate film 17 and is packaged to obtain a gel-like nonaqueous electrolyte secondary battery.

  In addition, as the laminate film 17 which is a package, a conventionally well-known metal laminate film, for example, an aluminum laminate film, can be used. As the aluminum laminate film, a film suitable for drawing and suitable for forming the recess 17a for accommodating the battery element 10 is preferable.

  Usually, an aluminum laminate film has a laminated structure in which an adhesive layer and a surface protective layer are disposed on both sides of an aluminum layer, and a polypropylene layer (PP as an adhesive layer in order from the inside, that is, the surface side of the battery element 10). Layer), an aluminum layer as a metal layer, and a nylon layer or a polyethylene terephthalate layer (PET layer) as a surface protective layer.

  Moreover, as the laminate film 17 which is a package, in addition to the aluminum laminate film, it may be a single-layer or double-layer film and include a polyolefin film.

  And in this embodiment, as shown in FIGS. 2-4, the battery element 10 is packaged by the above-mentioned laminate film 17, and the circumference | surroundings of the battery element 10 are welded and sealed to make the battery 20.

  As the resin of the exterior material 3, it is preferable to use a thermosetting resin. However, in order to improve productivity, positioning accuracy, and production tact, a thermoplastic resin, a cured curable resin, or a metal is partially used. A plate or a metal part may be used.

  As the thermoplastic resin, conventionally known resins can be used, but in particular, polyethylene, polypropylene, polyamide and polycarbonate are preferably used, from the viewpoints of adhesiveness with the thermosetting resin, flame retardancy and mechanical strength. It is more preferable to use polyamide or polycarbonate.

  In the case of a curable resin, a conventionally known resin can be used. Similarly, an acrylic resin, an epoxy resin, and a urethane resin are preferably used, and a resin that fills a mold, that is, a resin that is a main component of an exterior material. If the same resin is used, it is more preferable from the viewpoints of reduction in raw material costs, sharing of production equipment, and strength such as adhesion.

  Although various metals, such as aluminum, copper, stainless steel, iron, and nickel, can be used for a metal component, it is preferable to use aluminum and stainless steel from a viewpoint of intensity | strength and a moldability. Since metal parts have conductivity, it is preferable to cover them with tape or the like in order to ensure insulation between the tabs and the substrate. For thin metal parts, processing such as edge processing is effective in order to prevent a situation in which another part is damaged during the production process.

  Further, the exterior material 3 can be a composite material including a shape maintaining polymer and a filler such as a metal oxide or a metal nitride. At this time, the shape maintaining polymer constituting the exterior material 3 is a constituent resin having affinity, compatibility or reactivity with a filler such as metal oxide or metal nitride, and having high dimensional accuracy and strength. It is preferable that the curable resin is any one of a urethane resin, an acrylic resin, and an epoxy resin.

  The curable resin can take several tens of seconds of curing time compared to the thermoplastic resin, so the exterior material has a thickness of about 100 μm to several tens of μm or several μm compared to the thickness of several hundred μm so far. 3 can be formed, but if the curing time is too long, the tact time becomes long, and the occupation time of the apparatus becomes long, resulting in poor productivity. Therefore, it is preferable to keep the curing time high at a temperature that the battery 20 can withstand. The temperature at this time is preferably 30 ° C. or higher and 100 ° C. or lower, more preferably 50 ° C. or higher and 90 ° C. or lower.

  The shape maintaining polymer constituting the exterior material 3 requires mechanical strength, but the surface hardness and the impact resistance at the time of dropping are not compatible. A substance such as a polymer has a crystalline part and a non-crystalline part even if each individual molecule is long and looks like a simple solid at first glance.

  The non-crystalline portion can be partially moved when viewed microscopically by micro-Brownian motion, so that the molecular chain can be deformed or moved to some extent, and can be bent. It can be stretched. However, when the temperature is lowered, the partial mobility of the molecular chain is lost and the glass state is obtained, the flexibility is lost, and the hard state can be maintained.

  Therefore, if the hardness is simply pursued, if the crystallinity is high and the non-crystalline part is not heated to a certain extent, the free movement of the molecular chain is hindered, and therefore it is easily broken. On the other hand, when seeking flexibility, there are many non-crystalline parts, and the majority of molecular chains are not crosslinked enough to move freely even at room temperature, so they are excellent in impact resistance but inferior in mechanical strength. It becomes.

  For this reason, the shape maintaining polymer used as the exterior material 3 preferably has a long molecular chain and a high crystallinity in order to maintain rigidity, but in order to develop a flexibility that can withstand an impact when dropped. If there are too many cross-linking points, there is a risk of easily breaking.

  Therefore, as a curing agent, there are two curing points that have a polymer chain that contributes to flexibility as a long chain, and three crosslinking points that contribute to the realization of hardness and a high glass transition point by increasing the number of crosslinking points. It is preferable to use two or more curing agents in combination.

  When the bending strength and bending elastic modulus obtained from the plastic-bending property test method (JIS-K7171) were tested for the exterior material 3, the bending strength is preferably 10 MPa or more and 120 MPa or less, more preferably 70 MPa or more and 100 MPa or less. there were. The flexural modulus is preferably 30 MPa or more and 3000 MPa or less, more preferably 1000 MPa or more and 2500 MPa or less.

  Furthermore, according to the JIS-K7215 plastic durometer hardness test method, which is also an index of puncture resistance, the exterior material 3 preferably has a surface hardness in the range of D30-D99, more preferably in the range of D60-D85. Is good.

  The glass transition point is not less than the steady temperature and not more than the thermal runaway temperature because the pressure release part of the packaging body such as a laminate film and the pressure release part set so as to be inferior in strength work as the exterior body. More preferably, it is the range of 45 to 120 degreeC, More preferably, it is 60 to 110 degreeC.

  Furthermore, as the metal oxide and nitride filler constituting the exterior material 3, oxides of silicon (Si), aluminum (Al), titanium (Ti), zirconium (Zr), zinc (Zn) and magnesium (Mg) Or any mixture of these oxides and nitrides. Such metal oxide and nitride filler serve to improve the hardness and heat dissipation of the outer packaging material 3 and are arranged in contact with the shape maintaining polymer, and may be mixed in the shape maintaining polymer, for example. In this case, it is preferable that the shape-maintaining polymer is uniformly dispersed throughout.

  The mixing amount of the metal oxide and nitride filler can be appropriately changed according to the polymer type of the shape maintaining polymer, etc., but when the mixing amount with respect to the mass of the shape maintaining polymer is less than 0.1%, dehydration is performed. Insufficient amount of metal oxide and nitride filler serving as an agent makes stable production difficult and seasonal fluctuations in resin characteristics may occur. On the other hand, if the amount of contamination exceeds 60%, Problems with formability and ceramic brittleness may occur. Therefore, the mixing amount of the metal oxide and the nitride filler is preferably about 0.1 to 60% with respect to the mass of the shape maintaining polymer.

  In addition, when the average particle size of the metal oxide and nitride filler is reduced, the hardness increases, but there is a risk of affecting the filling property at the time of molding, resulting in a problem in productivity, and conversely, the metal oxide and nitride When the average particle size of the filler is increased, it is difficult to obtain the target strength, and there is a possibility that sufficient dimensional accuracy as the battery pack 1 cannot be ensured. Therefore, the average particle size of the metal oxide and nitride filler is preferably 0.5 to 40 μm, and more preferably 2 to 20 μm.

  Furthermore, various shapes such as a spherical shape, a scale shape, a plate shape, and a needle shape can be adopted as the shape of the metal oxide and the nitride filler. Although not particularly limited, a spherical shape is preferable because it is easy to produce and can be obtained at a low cost with a uniform average particle diameter, and a needle-like shape having a large aspect ratio is preferable because it can easily increase the strength as a filler. . Moreover, a scale-like thing is preferable at the point which can improve a filling property, when content of a filler is increased. In addition, it is possible to mix and use fillers having different average particle diameters or to mix and use fillers having different shapes depending on applications and materials.

  As described above, the exterior material 3 in the battery pack 1 of the present invention can contain various additives in addition to the shape-maintaining polymer and the predetermined metal oxide and nitride filler. In the maintenance polymer, an ultraviolet absorber, a light stabilizer, a curing agent, or any mixture thereof can be added to coexist with the metal oxide and the nitride filler.

  The exterior material 3 has a small thickness, for example, the thickness of the shape maintaining polymer layer is 1000 μm or less. When the thickness of the layer of the shape maintaining polymer exceeds 1000 μm, even if the battery pack 1 is manufactured using the exterior material 3, it may be difficult to exhibit the merit in terms of volume energy density. More preferably, the thickness of the layer of the shape maintaining polymer is 300 μm or less, and the thinner it is, as long as the required mechanical strength and impact resistance can be satisfied.

  As described above, the outer packaging material 3 is thinner than the conventional one and can realize the battery pack 1 having high strength, and can also realize the reduction in size and weight of the battery pack 1. Moreover, any one of an ultraviolet absorber, a light stabilizer and a curing agent is used together with the metal oxide and nitride filler as described above, and a curable resin of any one of a urethane resin, an acrylic resin and an epoxy resin is used. By using it, since it is thinner than a metal plate and can be processed with excellent productivity, not only the energy density of the obtained battery is improved, but also the formation of the battery pack 1 is easy and the dimensional accuracy is high. As a result, the yield is improved, and in addition, the degree of freedom in designing the size, shape, and strength according to various applications is expanded.

  Next, an embodiment of a method for manufacturing the battery pack 1 having the above configuration will be described.

<First Embodiment of Battery Pack Manufacturing Method>
In the method for manufacturing the battery pack 1 of the present invention, as shown in FIG. 5A, the primary exterior portion 3A having the battery 20 and the positioning portions P1 and P2 of the protection circuit board 2 as a part of the exterior material 3 is provided. Form.

  In this step, the primary exterior part 3A is formed by RIM molding (reaction injection molding) using the main agent M1 and the curing agent M2 using the primary molding die 51 including a pair of upper and lower split dies 51A and 51B. In addition to the split molds 51A and 51B, the primary mold 51 includes an injection machine IJ and a gate G for the main agent M1 and the curing agent M2, a slide core 51C that forms a terminal portion, and the like. The primary exterior portion 3A in the illustrated example covers one side of the battery 20 and the protection circuit board 2 and has concave positioning portions P1 and P2.

  Next, in the manufacturing method, as shown in FIG. 5B, the battery 20 and the protection circuit board 2 are arranged in the positioning portion of the primary exterior portion 3A. Then, as shown in FIG. 5C, at least one secondary exterior part 3 </ b> B that is the remaining part of the exterior material 3 is formed on the primary exterior part 3 </ b> A, the battery 20, and the protection circuit board 2.

  In this step, a secondary mold 52 provided with a split mold (lower mold) 51B that forms the outer side of the exterior material in the primary mold 51 and another split mold 52A that forms a cavity between the split mold 51B. Is used. And the secondary exterior part 3B is similarly formed by RIM shaping | molding. The secondary exterior part 3B in the illustrated example covers the remaining side of the battery 20 and the protection circuit board 2 and is integrated with the primary exterior part 3A to form the exterior material 3.

  Thereby, the battery pack 1 formed by covering the battery 20 and the protection circuit board 2 with the exterior material 3 is obtained. Thereafter, as shown in FIG. 5D, the secondary mold 52 is opened, the gate G is cut off, and the battery pack 1 is released by, for example, a vacuum cup VC.

  Here, in the manufacturing method, as a more preferable embodiment, at least one of corona discharge treatment, ultraviolet irradiation treatment, primer treatment, adhesive treatment, and solvent treatment is performed on the interface between the exterior portions 3A and 3B. Thus, the exterior material 3 is formed by integrating the exterior materials 3A and 3B. Thereby, the wettability of an interface can be improved. In particular, in the corona discharge treatment, the effect is exhibited in about 0.1 seconds to 0.5 seconds, so that productivity can be increased.

  Moreover, it is preferable that the said manufacturing method uses an adhesive agent or a primer, in order to raise the adhesive strength of an interface. Examples of the adhesive or primer include an acrylic resin emulsion adhesive, a urethane resin emulsion adhesive, an ethylene-vinyl acetate resin emulsion adhesive, an epoxy resin emulsion adhesive, a vinyl acetate resin emulsion adhesive, and an aqueous polymer-isocyanate system. Adhesives, styrene-butadiene rubber latex adhesives, polyamide resin hot melt adhesives, polyvinyl alcohol adhesives, and the like can be used, and desired adhesive strength and good handling properties can be realized.

  Further, the adhesive or primer may be selected from acrylic, urethane, epoxy, chloroprene rubber, cyanoacrylate, silicone, styrene / butadiene rubber and polystyrene resin. If you use α-olefin adhesive, ether cellulose, acrylic, urethane, epoxy, chloroprene rubber, cyanoacrylate, silicone, styrene-butadiene rubber and polystyrene resin, Desired adhesive strength and good handling properties can be obtained.

  In particular, acrylic resin-based primers, epoxy resin-based primers, modified silicone-based primers, and one-component urethane-based primers are particularly preferable, and desired adhesive strength can be obtained by spraying in a gaseous state as well as coating. Therefore, it is possible to achieve both improvement in productivity and improvement in performance.

  Furthermore, in the said manufacturing method, as a more preferable embodiment, the interface with the secondary exterior part 3 in the said primary exterior part 3A can be roughened. Such an interface can be formed by roughening one surface of the split mold that forms the interface. When the interface is roughened in this way, the contact area between the interfaces increases, and the interfaces become engaged with each other by a so-called hook effect due to minute irregularities, and the adhesive strength can be further increased.

  According to the above battery pack manufacturing method, it is possible to provide a battery pack with high productivity that has both high dimensional accuracy and mechanical strength, as well as reduced size and weight. Further, in the manufacturing method, as described above, the primary exterior portion 3A is formed using the primary molding die 51 including at least a pair of split dies 51A and 51B, and one split die 51B of the primary molding die 51 and this The secondary exterior part 3B is formed using the secondary shaping | molding die 52 provided with the other split type | mold 52A corresponding to. As a result, one mold release mark is formed on the same surface of the primary exterior part 3A, the appearance of the battery pack is improved, and simplification of the equipment is realized by using a part of the split mold 51B. In addition, the facility cost and manufacturing cost can be further reduced.

  In the manufacturing method, it is possible to reliably position an indefinite battery element having a dimensional error of several hundred μm to nearly 1 mm by forming the exterior material 3 in at least two steps. As the discharge condition of the resin for the exterior material, either filling (casting) or potting (resin filling) by a discharger can be selected. Filling with a discharger is preferable in terms of stable discharge conditions. Potting does not leave any gate marks and does not require gate cut processing, uses adhesive resin, does not require adhesive tape, does not occupy a dispenser, and shortens the occupancy time of the mold. It is preferable in that it can be taken.

  In any case, when the molding is performed a plurality of times, the battery 20 and the protective circuit board 2 are covered with the exterior material 3, and then the cross section is obtained by mechanical polishing, ultra-microtome or the like, and the cross section is observed. For example, it is possible to easily determine the number of moldings by confirming the presence of an interface at the time of molding a plurality of times. That is, the battery pack obtained by the manufacturing method can be specified.

<Second Embodiment of Battery Pack Manufacturing Method>
In the method of manufacturing the battery pack 1 in this embodiment, as shown in FIG. 6A, a primary molding die 61 having concave positioning portions P1, P2 is used, and first, the positioning portions P1, P2 of the primary molding die 61 are used. The battery 20 and the protection circuit board 2 are respectively disposed in

  As shown in FIG. 6B, the primary mold 61 includes one split mold 61A having positioning portions P1 and P2 and the other split mold 61B corresponding thereto. The one split mold 61A has through holes H1 and H2 communicating with the outside of the mold from the positioning portions P1 and P2. After the battery 20 and the protection circuit board 2 are set, the through holes H1 and H2 are set. Is sucked from the outside to fix the battery 20 and the protection circuit board 2 with the negative pressure.

  In the manufacturing method, after the battery 20 and the protective circuit board 2 are set in one split mold 61A as shown in FIG. 6A, the primary mold 61 is formed while suctioning as shown in FIG. 6B. The resin is supplied to the cavity by closing, and the primary exterior portion 3 </ b> A that is a part of the exterior material 3 is formed on the battery 20 and the protection circuit board 2. The primary exterior part 3A of the illustrated example covers one side of the battery 20 and the protection circuit board 2 as in the first embodiment.

  Thereafter, in the manufacturing method, as shown in FIGS. 6C and 6D, at least one secondary serving as the remaining portion of the exterior material 3 with respect to the primary exterior 3 </ b> A, the battery 20, and the protection circuit board 2. The exterior part 3B is formed. The secondary exterior part 3 </ b> B in the illustrated example covers the remaining side of the battery 20 and the protection circuit board 2. Thereby, all the exterior parts 3A and 3B are integrated to form the exterior material 3, and the battery pack 1 in which the battery 20 and the protection circuit board 2 are covered with the exterior material 3 is obtained.

  In this step, the other split mold 61 </ b> B that forms the outside of the primary exterior portion 3 </ b> A in the primary mold 61 is also used as the secondary mold 62. That is, as shown in FIG. 6 (c), the secondary mold 62 is composed of the split mold 61B and the split mold 62A corresponding to the split mold 61B by turning the other split mold 61B of the primary mold 61 upside down. . Thereby, an effect | action and effect equivalent to 1st Embodiment can be acquired.

<Third Embodiment of Battery Pack Manufacturing Method>
In the method of manufacturing the battery pack 1 in this embodiment, as shown in FIG. 7A, the main agent M1 and the curing agent M2 are supplied to the lower mold 71 having a concave molding space. The lower mold 71 is composed of a plurality of divided molds 71A to 71C. Next, as shown in FIG. 7B, by closing the lower mold 71 and the upper mold 72 corresponding thereto, the primary exterior part which is a part of the exterior material 3 as shown in FIG. 7C. 3A is formed. The primary exterior part 3 </ b> A in the illustrated example covers one side of the battery 20.

  Thereafter, in the manufacturing method, after the battery 20 and the protective circuit board 2 are arranged on the primary exterior portion 3A, at least one secondary exterior portion that becomes the remaining portion of the exterior material 3 is formed. In this embodiment, a plurality of secondary exterior parts are formed.

  That is, in this embodiment, as shown in FIG. 7D, the battery 20 and the protection circuit board 2 are set, and further, the battery 20 is suppressed by the fixture 73, and then as shown in FIG. Then, resin is supplied from the protective circuit board 2 side to form the first secondary exterior part 3B1. Thereafter, as shown in FIG. 7 (f), the lower mold 71 is closed with a plate 74 having a gate, and a resin is supplied into the lower mold 71. As shown in FIG. Part 3B2 is formed. Thereby, the exterior material 4 which integrated each exterior part 3A, 3B1, 3B2 is formed.

  Then, after removing the plate 74 as shown in FIG. 8B and performing gate cutting, the lower mold 71 is disassembled as shown in FIG. 8C, so that the battery 20 and the protection circuit as shown in FIG. A battery pack 1 formed by covering the substrate 2 with the exterior material 3 is obtained.

  Here, in the manufacturing method described above, the positioning accuracy of the battery 20 and the protection circuit board 2 can be further increased by using positioning components as shown in FIGS. These positioning components function as positioning portions for the battery 20 and the protection circuit board 2 in the mold, and are embedded in the exterior material 3 so that they can function as a reinforcing material for the battery pack.

  The positioning component G1 shown in FIG. 10A has a frame structure along the three sides around the battery 20. The positioning component G1 is sandwiched between the concave portion 17a and the side portion 17b of the battery 20 as shown in FIG. 10 (b), or is adhered to the battery 20 as shown in FIG. 10 (c). For this bonding, an adhesive or an adhesive tape is used. Even when such a positioning component G1 is used, the mold releasability is excellent. This is because if the eject pin is taken out from the maximum surface side, the dent will not remain.

  A positioning component G2 shown in FIG. 11 has a rectangular frame structure corresponding to the battery 20, and has an eject pin receiving portion 75 in a portion corresponding to the eject pin of the molding die. In the example of illustration, it has the receiving part 75 used as a part of surface of an exterior material in the four corners of a frame structure. Thereby, at the time of mold release, it is possible to prevent dents from being ejected on the surface of the exterior material, and to further enhance the appearance of the battery pack.

  In addition, the shape of the receiving part 75 can employ | adopt various shapes, such as circular and a polygon, other than the fan shape of the example of illustration. In addition, when the positioning component G2 having the receiving portion 75 is used, there is no dent of the eject pin, and laser printing is possible without attaching a label or the like, thereby reducing the cost and increasing the capacity of the battery. It can also be achieved.

  When positioning parts G1 and G2 having a frame structure as shown in FIGS. 10 and 11 are employed, the resin that is filled later does not exist on the surface of the parting line of the mold opening, so that it is excellent in releasability. There is.

  In addition to the positioning function, the positioning component G3 shown in FIG. 12 also functions as a top cover that covers the surface on which the gold terminal 76 of the protective circuit board 2 is provided after the exterior material is molded. The positioning component G3 has a plurality of (two in the illustrated example) notches 82 that engage with the mold, and has a groove 77 and an opening 78 on opposite side walls. The protective circuit board 2 is held in a state where the ends of the two terminals are fitted and the surface with the gold terminal 76 is in close contact.

  When this positioning component G3 is used, a molding die 80 having a projection 79 corresponding to the opening 78 is used, and the protection circuit board 2 is pressed by the projection 79, so that the protection circuit board 2 can be formed when molding the exterior material. The positioning is made more reliable, and the protection circuit board 2 is prevented from being displaced above the softening temperature of the resin.

   Similar to the component shown in FIG. 12, the positioning component G4 shown in FIG. 13 functions as a top cover that covers the surface with the gold terminals 76 of the protective circuit board 2 after molding of the exterior material, in addition to the positioning function. This positioning component G4 has a plurality of (two in the illustrated example) notches 82 that engage with the mold, and a plurality of claw portions 81 on opposite side walls. It is desirable to provide at least three claw portions 81. As shown in the example, two claw portions 81 are arranged at an appropriate interval on one side wall, and one claw portion 81 is provided at the center of the other side wall. Place.

  The positioning component G4 is in a state in which the surface of the protective circuit board 2 with the gold terminal 76 is brought into close contact by the spring action of the claw part 81 by fitting the protective circuit board 2 with elastic deformation of the claw part 81. Thus, the protective circuit board 2 is more reliably positioned when molding the exterior material, and the shift of the protective circuit board 2 above the softening temperature of the resin is prevented.

  As in the positioning parts G3 and G4 shown in FIGS. 12 and 13, in the configuration in which the surface with the gold terminal 76 of the protection circuit board 2 is the top cover part, the filling resin oozes out from the back surface side of the protection circuit board 2. It is possible to prevent a situation in which the gold terminal 76 of the protection circuit board 2 is covered with resin.

  Further, when the above-mentioned separate parts are not used, the merit is higher in terms of capacity, strength and cost. When a separate part is not used, it is preferable that the adhesive resin is easily released. Any conventionally known release agent can be used as the release agent, and in particular, silicon-based and fluorine-based release agents are preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

(Examples 1-12 and Comparative Examples 1-3)
Examples 1 to 12 and Comparative Examples, with different materials for the packaging material, the filler contained in the resin, the curing method, the resin elongation rate, the number of injections of the resin, the parts other than the battery and the protective circuit board, and the packaging material Each battery pack of 1-3 was produced. Then, the rated density of each battery pack, the volume retention rate and dimensional change rate after 500 cycles of charge / discharge, the variation in thickness, the time from resin filling to mold release to mold release, and the maximum temperature in the overcharge test are investigated. It was. The results are shown in Table 1.

  As is clear from Table 1, the battery packs of Examples 1 to 12 are all good compared to Comparative Examples 1 to 3, have sufficient mechanical strength, and have no thickness variation. It was confirmed that the dimensional accuracy was high.

(Examples 13 to 35)
Among the battery packs in which the exterior material is formed a plurality of times according to the battery pack manufacturing method of the present invention, Examples 13 to 32 in which the interface between the exterior parts is not treated and Examples 33 to 35 in which the treatment is performed The tensile adhesive strength test of the adhesive according to JIS K6849 was carried out to evaluate the tensile shear adhesive strength. The results are shown in Table 2.

  As is clear from Table 2, even in Examples 13 to 32 where the interface between the exterior parts was not treated, sufficient tensile shear adhesive strength was obtained, but the interface was treated between the exterior parts. For Examples 13 to 32, it was confirmed that the tensile shear bond strength was remarkably increased.

  The configuration of the battery pack and the manufacturing method thereof according to the present invention is not limited to the above embodiments, and the configuration can be changed as appropriate without departing from the gist of the present invention. In each of the above embodiments, a configuration in which a single battery and a protection circuit board are covered with an exterior material is illustrated. However, a battery group including a plurality of batteries is provided, and the battery group and the protection circuit board are covered with an exterior material. Naturally, the battery pack and the manufacturing method thereof can be used.

  DESCRIPTION OF SYMBOLS 1 ... Battery pack, 2 ... Protection circuit board, 3 ... Exterior material, 10 ... Battery element, 11 ... Positive electrode, 12 ... Negative electrode, 13a, 13b ... Separator, 17 ... Laminate film (packaging body), 20 ... Battery, 3A ... Primary exterior part, 3B, 3B1, 3B2 ... Secondary exterior part, 51, 61 ... Primary mold, 51A, 51B ... Split mold, 61A, 61B ... Split mold, 52, 62 ... Secondary mold, 52A, 62A ... Split mold, 71 ... molding die, G1 to G4 ... positioning parts (positioning parts) P1, P2 ... positioning part.

Claims (9)

A battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed therebetween is wrapped in a packaging body, a protection circuit board for the battery, and a molding space for housing the battery and the protection circuit board A battery pack including an exterior material that integrally covers the battery and the protection circuit board in a state in which the terminal of the battery is led out to the outside by filling and curing the resin,
The exterior material includes a primary exterior part that partially covers the battery and the protection circuit board, and at least one secondary exterior part that partially covers the battery and the protection circuit board, and the entire exterior part is integrated. A battery pack made up of.   The battery pack according to claim 1, wherein the resin of the exterior material is a curable resin selected from a urethane resin, an acrylic resin, and an epoxy resin.   The battery pack according to claim 1, wherein the package is an aluminum laminate film. A battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed therebetween is wrapped in a packaging body, a protection circuit board for the battery, and a molding space for housing the battery and the protection circuit board When manufacturing a battery pack including an exterior material that integrally covers the battery and the protection circuit board in a state where the terminal of the battery is led out to the outside by filling and curing the resin,
After forming the primary exterior part which has the positioning part of the said battery and a protection circuit board as a part of said exterior material, and arrange | positioning the said battery and the protection circuit board in the positioning part of the said primary exterior part, the said primary exterior part and battery And the manufacturing method of the battery pack which forms all the exterior parts and forms the said exterior material by forming the at least 1 secondary exterior part used as the remaining part of the said exterior material with respect to a protection circuit board. A battery in which a battery element formed by winding or laminating a positive electrode and a negative electrode with a separator interposed therebetween is wrapped in a packaging body, a protection circuit board for the battery, and a molding space for housing the battery and the protection circuit board When manufacturing a battery pack including an exterior material that integrally covers the battery and the protection circuit board in a state where the terminal of the battery is led out to the outside by filling and curing the resin,
Using a molding die provided with a positioning part for the battery and the protection circuit board,
A battery and a protection circuit board are disposed on the mold, and a primary exterior part which is a part of an exterior material is formed on the battery and the protection circuit board, and then the primary exterior part, the battery and the protection circuit board are formed. A method of manufacturing a battery pack in which all the exterior parts are integrated to form the exterior material by forming at least one secondary exterior part to be the remaining part of the exterior material.   Using a primary mold having at least a pair of split molds, the primary exterior part is formed, and using a secondary mold having one split mold of the primary mold and the other split mold corresponding thereto. The method for manufacturing a battery pack according to claim 4 or 5, wherein one release mark is formed on the same surface of the primary exterior part by forming the secondary exterior part.   The method for producing a battery pack according to claim 4 or 5, wherein at least one of a corona discharge treatment, an ultraviolet irradiation treatment, a primer treatment, an adhesive treatment, and a solvent treatment is performed on an interface between the exterior portions.   8. At least one of the adhesive and the primer is selected from acrylic, urethane, epoxy, chloroprene rubber, cyanoacrylate, silicone, styrene / butadiene rubber, and polystyrene resin. The manufacturing method of the battery pack as described in any one of.   The method for manufacturing a battery pack according to claim 4 or 5, wherein an interface between the primary exterior portion and the secondary exterior portion is roughened.

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