JP5482805B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack, and more particularly to a battery pack applied to a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.

  In recent years, many portable electronic devices such as a camera-integrated VTR (Videotape Recorder), a mobile phone, or a laptop computer have appeared, and their size and weight have been reduced. Along with this, the demand for batteries used as power sources for portable electronic devices has been growing rapidly, and in order to reduce the size and weight of the devices, the battery design has also been made lighter and thinner, and the accommodation space inside the devices is more efficient. It is required to be used for. As a battery that satisfies such a requirement, it is known that a lithium ion secondary battery having a large energy density and output density is most suitable.

Also in the development of such lithium ion secondary batteries, practical applications such as batteries having a high degree of freedom in shape, thin and large area sheet type batteries, and thin and small area card type batteries are desired.
On the other hand, in recent years, it has been reported that a thin battery as described above can be obtained by producing a thin battery using a film-like exterior material such as an aluminum laminate film (for example, Non-Patent Document 1).

Norio Takami, “Ultra-thin aluminum laminate exterior lithium-ion battery”, Toshiba Review, Toshiba Corporation, February 2001, Vol. 56 No. 2, p. 10-13

In FIG. 1, the external appearance of the battery 1 currently disclosed by the nonpatent literature 1 is shown.
This thin battery 1 is produced by covering a battery element with a flat battery element produced by laminating and winding a positive electrode and a negative electrode with a separator interposed between them, and sealing the periphery of the battery element. is there.
The positive electrode terminal 2a and the negative electrode terminal 2b connected to the positive electrode and the negative electrode are led to the outside of the battery from, for example, one side of the thin battery 1, and are sealed after leaving one side around the battery element and then not sealed. The thin solution as described above can be obtained by injecting the electrolytic solution from the above and finally sealing the lead-out sides of the positive electrode terminal 2a and the negative electrode terminal 2b.

  Since this thin battery has an aluminum laminate film having a thickness of about 100 μm as an exterior, its strength is weaker than that of a metal can, and it is difficult to use it as it is in a battery pack. Therefore, a battery pack in which a battery element covered with a laminate film is accommodated in a pack housing made of plastic and firmly fixed with a double-sided tape or the like is widely used. Further, it is known that the resistance when the battery pack is dropped can be improved by increasing the thickness of the casing.

  However, in such a conventional thin battery, since the bonding location between the surface of the battery and the housing is limited, if the drop height reaches a certain height, the battery element itself is not damaged, but the soft battery exterior In some cases, the load concentrates on the metal layer and tears, or pinholes are generated in the metal layer and the resin layer penetrates and moisture enters.

In this case, even if the exterior of the pack is not deformed and can be used by being attached to the device, if the exterior is torn, moisture in the atmosphere will continue to react with the electrode and electrolyte, generating harmful gases, and only the pinhole Even in this case, the intrusion moisture reacts and gasifies at a time during charging, so that the battery pack may be abnormally swollen and the portable device may be damaged.
Further, when manufacturing a pack housing, a thickness of approximately 300 μm or more is necessary to ensure the technical limit and strength of thin plastic molding, and it is difficult to increase the capacity of the battery that can be accommodated.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to increase the reliability and safety after dropping by suppressing weighted concentration on the soft exterior material, Batteries that are strong enough to withstand deformation, etc. in the event of a slight drop, and have excellent cognition that can not be loaded or charged in the target device in the event of an impact that would cause damage to the soft exterior material. An object of the present invention is to provide a battery pack excellent in volume efficiency that can maximize the element volume.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by appropriately controlling the bonding state between the soft exterior material and the hard exterior material, thereby completing the present invention. It came to do.

That is, the first battery pack of the present invention is formed by winding or laminating a positive electrode and a negative electrode with a separator interposed therebetween, and a battery element having a nonaqueous electrolyte composition,
A soft exterior material comprising a laminate film having a structure in which a thermal adhesive layer, a metal layer and an exterior layer are sequentially laminated, and exteriors the main part of the battery element;
A hard exterior material comprising a laminate film having a three-layer structure in which a thermal adhesive layer, a metal layer, and an exterior layer are sequentially laminated, and covering the remainder of the battery element and the soft exterior material;
An adhesive member;
A non-aqueous electrolyte secondary battery formed by sealing a battery element by bonding a soft exterior material and a hard exterior material along the periphery of the battery element, with the electrode terminals of the positive electrode and the negative electrode being led out to the outside,
A protective circuit board housed in a hard exterior material and capable of controlling the voltage and current of the non-aqueous electrolyte secondary battery,
The battery element and the soft exterior material are in close contact,
In the peripheral portion of the battery element, the soft exterior material and the hard exterior material are joined together by melting the thermal adhesive layer of the soft exterior material and the thermal adhesive layer of the hard exterior material facing each other,
The exterior layer of the soft exterior material has a thermal conductivity of ¹ Wm ⁻¹ K ⁻¹ or less and a melting temperature higher than that of the thermal adhesion layer of the hard exterior material,
The hard exterior material is folded so as to wrap the battery element, and the end of the folded hard exterior material and the surface of the soft exterior material that covers the main part of the battery element are not melted and the exterior layer of the soft exterior material does not melt The adhesive member is joined by melting.

  According to the present invention, since the joining state between the soft exterior material and the hard exterior material is appropriately controlled, the weight concentration on the soft exterior material is suppressed, and the reliability and safety after the fall are improved. A battery element volume that has excellent strength that can not be loaded or charged into the target device and can be accommodated in the event of an impact that would cause damage to the soft exterior material in the unlikely event that it has the strength to withstand deformation when dropped. Thus, it is possible to provide a battery pack excellent in volumetric efficiency that can be expanded to the maximum.

2 is a schematic diagram showing a configuration of a battery described in Non-Patent Document 1. FIG. 1 is a perspective view of an embodiment of a battery pack according to the present invention. It is a top view which shows the structure of one Embodiment of the battery pack of this invention. It is a perspective view which shows the structure of the battery element in one Embodiment of the battery pack of this invention. It is a perspective view which shows the structure of the battery in one Embodiment of the battery pack of this invention. It is sectional drawing which shows the structure of the soft laminate film in one Embodiment of the battery pack of this invention. It is a disassembled perspective view which shows the structure of the battery in one Embodiment of the battery pack of this invention. It is a perspective view which shows the structure of the battery in one Embodiment of the battery pack of this invention. It is sectional drawing which shows the structure of the hard laminate film in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is the perspective view and sectional drawing which show the structure of the battery assembly in one Embodiment of the battery pack of this invention. It is sectional drawing which shows an example of the other structure of a hard laminate film. It is sectional drawing which shows an example of the other structure of a hard laminate film. It is sectional drawing which shows the structure of the hard laminate film in other embodiment of the battery pack of this invention. It is the top view and side view which show one Embodiment of the other battery pack of this invention. It is sectional drawing which shows one Embodiment of the other battery pack of this invention. It is sectional drawing which shows other embodiment of the other battery pack of this invention, and shows the state of a manufacture process. FIG. 22 is a cross-sectional view showing still another embodiment of another battery pack of the present invention and showing the state of the manufacturing process.

  Hereinafter, the battery pack of the present invention will be described in detail with reference to the drawings. In the present specification, “%” for concentration, content, blending amount, etc. represents mass percentage unless otherwise specified.

(Embodiment 1)
In this embodiment, a configuration using a four-layer hard laminate film as an exterior material will be described.
In FIG. 2, the external appearance of the battery pack of the lithium ion polymer secondary battery showing one Embodiment of the battery pack of this invention is shown. This battery pack 40 contains a lithium ion polymer battery, which is an example of a nonaqueous electrolyte secondary battery, in a hard laminate film 41 as a hard exterior material, and a top cover 42 and a rear cover 43 that are resin-molded covers at both end openings. The product label 46 is disposed as necessary.

  Here, in the first embodiment and the second embodiment, the battery element is packaged with a soft laminate film, which is a soft sheath material, and the battery is packaged with a hard laminate film 41. A circuit pack is connected and the top cover 42 and the rear cover 43 are fitted together, and the structure as shown in FIG. 2 is referred to as a battery pack.

  FIG. 3 shows the configuration of the battery pack 40. The battery pack 40 includes a battery 50 whose battery elements are covered with a soft laminate film, a circuit board 44, a top cover 42, and a rear cover 43, and the battery 50 is covered with a hard laminate film 41.

The top cover 42 is a resin-molded cover that is provided at the top portion from which the positive electrode and the negative electrode are led out and fitted into the opening of the battery assembly. The rear cover 43 is a resin-molded cover that is provided at the bottom of the battery and fitted into the opening of the battery assembly 45.
The top cover 42 and the rear cover 43 are bonded to the battery assembly 45 by heat sealing or the like after being fitted into the opening of the battery assembly 45. The top cover 42 is formed by fitting an upper holder 42a and a lower holder 42b, and a circuit board 44 is disposed between the upper holder 42a and the lower holder 42b.

The circuit board 44 has a protection circuit mounted in advance, and the positive terminal and the negative terminal derived from the battery 50 and the protection circuit are connected by resistance welding, ultrasonic welding, or the like. The protection circuit includes a temperature protection element that cuts off a current circuit of the battery when the battery becomes high temperature, such as a PTC element (Positive Temperature Coefficient) or a thermistor.
The battery pack 40 has a connection terminal with an electric device (not shown), and the top cover 42 is provided with a terminal window exposing the connection terminal with the electric device.

Next, the battery element will be described.
FIG. 4 shows the configuration of the battery element 59 used in the battery pack 45.
The battery element 59 has a belt-like positive electrode 51, a separator 53a, a belt-like negative electrode 52 disposed opposite to the positive electrode 51, and a separator 53b, which are sequentially laminated and wound in the longitudinal direction, not shown. A gel electrolyte is applied to both surfaces of the positive electrode 51 and the negative electrode 52.
Also, a positive electrode terminal 55a connected to the positive electrode 51 and a negative electrode terminal 55b connected to the negative electrode 52 are led out from the battery element 59, and a laminate to be packaged later is provided on both surfaces of the positive electrode terminal 55a and the negative electrode terminal 55b. Resin pieces 56a and 56b are coated to improve adhesion to the film. In addition, when using electrolyte solution, the injection process of electrolyte solution is provided later.

  Hereinafter, materials constituting the battery element 59 will be described in detail.

[Positive electrode]
The positive electrode 51 is formed by forming positive electrode active material layers 51a containing a positive electrode active material on both surfaces of a positive electrode current collector 51b. The positive electrode current collector 51b is made of, for example, a metal foil such as an aluminum (Al) foil.

The positive electrode active material layer 51a includes, for example, a positive electrode active material, a conductive agent, and a binder. These 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 can be formed by applying the slurry uniformly on the positive electrode current collector 51b by a doctor blade method or the like, drying at high temperature, and scattering the solvent.
Note that 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.

The positive electrode active material is mainly LiXMO ₂ (M in the formula represents at least one transition metal, and x varies depending on the charge / discharge state of the battery and is usually 0.05 to 1.10). A composite oxide of lithium and a transition metal is used. As the transition metal constituting the lithium composite oxide, cobalt (Co), Ni, manganese (Mn) or the like is used.

Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiNi _y Co _1-y O ₂ (0 <y <1).
A solid solution in which a part of the transition metal element is substituted with another element can also be used. Examples thereof include LiNi _0.5 Co _0.5 O ₂ and LiNi _0.8 Co _0.2 O ₂ . These lithium composite oxides can generate a high voltage and have an excellent energy density. Furthermore, TiS _2, MoS _2, may be used NbSe _2, V ₂ O no lithium metal sulfides such as ₅ or oxide as the positive electrode active material.

  As the conductive agent, for example, a carbon material such as carbon black or graphite is used. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride, or the like is used. Moreover, as a solvent, N-methylpyrrolidone etc. are used, for example.

The positive electrode 51 has a positive electrode terminal 15a connected to one end of the current collector by spot welding or ultrasonic welding. The positive electrode terminal 55a 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 conduct electricity.
Examples of the material of the positive electrode terminal 55a include Al.

[Negative electrode]
The negative electrode 52 is formed by forming negative electrode active material layers 52a containing a negative electrode active material on both surfaces of a negative electrode current collector 52b. The negative electrode current collector 52b is made of a metal foil such as a copper (Cu) foil, a Ni foil, and a stainless steel foil.

  The negative electrode active material layer 52a includes, for example, a negative electrode active material, a conductive agent if necessary, and a binder. These are uniformly mixed to form a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent to form a slurry. Next, this slurry is uniformly applied onto the negative electrode current collector 52b by a doctor blade method or the like, and dried at a high temperature to disperse the solvent, thereby forming the negative electrode active material layer 52a. Here, the negative 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 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 is used.
Specifically, examples of the carbon material that can be doped / dedoped with lithium include graphite, non-graphitizable carbon, graphitizable carbon, and the like. More specifically, pyrolytic carbons, cokes (pitch coke, Needle coke, petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (carbonized by firing phenol resin, furan resin, etc.), carbon fiber, activated carbon, etc. Can be used. Furthermore, as a material that can be doped or dedoped with lithium, a polymer such as polyacetylene or polypyrrole or an oxide such as SnO ₂ can be used.

In addition, various kinds of metals can be used as materials capable of alloying lithium, but tin (Sn), cobalt (Co), indium (In), Al, silicon (Si), and alloys thereof can be used. 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 Li metal plate may be used.
As the binder, for example, polyvinylidene fluoride, styrene butadiene rubber or the like is used. Moreover, as a solvent, N-methylpyrrolidone, methyl ethyl ketone, etc. are used, for example.

  Similarly to the positive electrode 51, the negative electrode 52 has a negative electrode terminal 55b connected to one end of the negative electrode current collector 52b by spot welding or ultrasonic welding. The negative electrode terminal 52b 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 conduct electricity. Examples of the material of the negative electrode terminal 52b include copper and Ni.

  The positive electrode terminal 55a and the negative electrode terminal 55b are preferably derived from the same direction, but there is no problem even if they are derived from any direction as long as no short circuit or the like occurs and there is no problem in battery performance. Moreover, the connection location of the positive electrode terminal 55a and the negative electrode terminal 55b is not limited to the above example as long as it is in electrical contact.

[Electrolytes]
As the electrolyte, that is, the non-aqueous electrolyte composition, an electrolyte salt and a non-aqueous solvent generally used for lithium ion batteries can be used.
Specific examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, ethylpropyl carbonate, and carbonates thereof. And other solvents in which hydrogen is substituted with halogen.
About these solvents, the 1 type may be used independently and multiple types may be mixed by predetermined composition.

As the electrolyte salt, one that dissolves in the non-aqueous solvent is used, and a combination of a cation and an anion is used. As the cation, an alkali metal or an alkaline earth metal is used. As the anion, Cl ⁻ , Br ⁻ , I ⁻ , SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ^{− and the} like are used.
_{Specifically, LiPF 6, LiBF 4, LiN} (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, LiClO 4 and the like. The electrolyte salt concentration is not a problem as long as it can be dissolved in the above solvent, but the lithium ion concentration is in the range of 0.4 mol / kg or more and 2.0 mol / kg or less with respect to the non-aqueous solvent. Is preferred.

In the case of using a gel electrolyte, a gel electrolyte is obtained by gelling an electrolyte solution in which an electrolyte and an electrolyte salt are mixed 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. About such a polymer, the 1 type may be used independently, and 2 or more types may be mixed and used for it.

[Separator]
The separator is composed of, for example, a porous film made of a polyolefin-based material such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric. A structure in which a porous film is laminated may be used. Among these, polyethylene and polypropylene porous films are the most effective.

  In general, the thickness of the separator is preferably 5 to 50 μm, more preferably 7 to 30 μm. If the separator is too thick, the amount of the active material filled decreases, the battery capacity decreases, and the ionic conductivity decreases and the current characteristics deteriorate. 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 51 and the negative electrode 52, impregnated in the positive electrode active material layer 51a and the negative electrode active material layer 52a, and then stored at room temperature or a drying step. Then, a gel electrolyte layer is formed. Next, using the positive electrode 51 and the negative electrode 52 on which the gel electrolyte layer is formed, the positive electrode 51, the separator 53 a, the negative electrode 52, and the separator 53 b are stacked and wound in this order to form the battery element 59.

Next, the battery element 59 is packaged and molded with a soft laminate film 57 to produce a battery 50 as shown in FIG.
Here, as the soft laminate film 57, a laminate film having a configuration shown in FIG. 6 can be used. The soft laminate film 57 includes a metal foil denoted by reference numeral 61 sandwiched between an exterior layer 62 made of a resin film and a thermal adhesive layer 63 (hereinafter, appropriately referred to as a sealant layer) 63 made of a resin film. It consists of a multilayer film having
The thicknesses of the exterior layer 62, the metal foil 61, and the sealant layer 63 are not particularly limited, but are about 15 μm, about 35 μm, and about 30 μm, respectively.

The metal foil 61 plays the most important role of protecting the contents by preventing the ingress of moisture, oxygen and light in addition to improving the strength of the exterior material, and appropriately uses stainless steel or nickel-plated iron as a material. However, aluminum (Al) is most suitable from the viewpoint of lightness, extensibility, cost, and ease of processing, and it is particularly preferable to use aluminum such as 8021O or 8079O.
Further, the metal foil 61, the exterior layer 62, and the sealant layer 63 are bonded together via adhesive layers 64 and 65.
When the exterior layer 62 and the sealant layer 63 have thermal adhesiveness with a metal, or when a base layer capable of thermal adhesion with the exterior layer 63 and the sealant layer 63 is formed on the metal surface, The adhesive layer 64 can be omitted.

  The exterior layer 62 is made of polyolefin, polyamide, polyimide and polyester, specifically nylon (Ny), polyethylene terephthalate (PET), polyethylene (PE) due to the beauty of appearance, toughness, heat resistance and flexibility. Polyethylene naphthalate (PEN) is used, and a plurality of these can be selected and used.

  Further, the sealant layer 63 is a portion that is melted by heat or ultrasonic waves and fused to each other, and is polyethylene (PE), unstretched polyethylene (CPE), unstretched polypropylene (CPP), polyethylene terephthalate (PET), nylon (Ny ), Low-density polyethylene (LDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (LLDPE) can be used, and a plurality of types can be selected and used.

The most common configuration of the laminate film is: exterior layer / metal foil / sealant layer = Ny / Al / CPP. Moreover, not only this combination but the structure of the other general laminate film as shown below is employable.
That is, exterior layer / metal film / sealant layer = Ny / Al / PE, PET / Al / CPP, PET / Al / PET / CPP, PET / Ny / Al / CPP, PET / Ny / Al / Ny / CPP, PET / Ny / Al / Ny / PE, Ny / PE / Al / LLDPE, PET / PE / Al / PET / LDPE, or PET / Ny / Al / LDPE / CPP. Of course, a metal other than Al can be used as the metal foil.

As shown in FIG. 7, the soft laminate film 57 forms a recess 57a by deep drawing, and after accommodating the battery element 59 in the recess 57a, the soft laminate film 57 further covers the opening of the recess 57a.
Next, three sides of the periphery of the battery element 59 are sealed by heat-sealing under reduced pressure, whereby the battery 50 is obtained. The battery element 59 is in close contact with the soft laminate film 57 by such heat fusion under reduced pressure.

  In the case of a battery using an electrolytic solution, the electrolytic solution is injected at this time. First, after two sides of the peripheral portion of the battery element are heat-sealed, a predetermined amount of electrolyte is injected from the remaining opening, and finally, the opening is heat-sealed to obtain a battery.

  The battery 50 may delete unnecessary portions of the top portion by trimming in consideration of a later manufacturing process. As shown in FIGS. 8A and 8B, by performing trimming along the line of reference symbol P, for example, interference between the top cover and the soft laminate film can be reduced.

[Production of battery assembly]
The battery thus produced is covered with a hard laminate film to produce a battery assembly. First, the configuration of the hard laminate film will be described.

  As shown in FIG. 9, the hard laminate film 41 includes a metal foil denoted by reference numeral 71 sandwiched between an exterior layer 72 made of a resin film and a sealant layer 73 made of a resin film, and further an adhesive layer under the sealant layer 73. 74, a multilayer film having moisture resistance and insulation. In this embodiment, the sealant layer 73 and the adhesive layer 74 form a thermal adhesive layer (composite adhesive layer) having thermal adhesiveness to nylon or the like.

In the hard laminate film 41, the thickness of the exterior layer 72, the metal foil 71, and the thermal adhesive layer (sealant layer 73 + adhesive layer 74) is not particularly limited, but is 115 μm or less, 330 μm or less, and about 25 to 50 μm ( Sealant layer), about 1 to 5 μm (adhesive layer).
The material is hard in order to ensure the obtained strength, but the thickness of the exterior layer 72 is set to 115 μm or less and the thickness of the metal foil 71 is set to 330 μm or less in order to prevent an increase in heat conduction resistance.

  As the metal foil 71, a hard metal material is used, and aluminum, stainless steel, copper, titanium, tin, tin, nickel-plated iron, or the like can be appropriately used as a material. Among these, aluminum (Al) and stainless steel (SUS) are most preferable, and it is particularly preferable to use aluminum such as 3003-H18, 3004-H18, and 1N30-H18 or stainless steel such as SUS304 and SUS430.

  Nylon (Ny), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN) is used for the exterior layer 72 in view of beauty of appearance, toughness, heat resistance, flexibility, and the like. It is also possible.

  The sealant layer 73 is a portion that is melted by heat or ultrasonic waves and fused to each other. In addition to polyethylene (PE), non-axially oriented polypropylene (CPP), polyethylene terephthalate (PET), nylon (Ny), low density polyethylene ( LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE) can be used, and a plurality of types can be selected and used.

The thermal adhesive layer 74 is for adhering the battery 50 and the hard laminate film 41 covered with the soft laminate film 57 without separately providing an adhesive member.
As the thermal adhesive layer 74, a resin material having excellent adhesiveness with Ny, PET, PEN and the like used as the outer layer of the soft laminate film 57 and having a melting temperature that does not affect the battery element is used. The thermal adhesive layer 74 uses a resin material having a lower melting point than the material used for the sealant layer 73.

  Specifically, ethylene vinyl acetate copolymer (EVA), ethylene acrylic acid copolymer, ethyl acrylate copolymer, methyl acrylate copolymer, methacrylic acid copolymer, methyl methacrylate copolymer, polyacrylonitrile, ethylene vinyl alcohol resin, polyamide resin, polyester resin Acid-modified polypropylene and ionomers can be used, and a plurality of types can be selected and used. These materials can be used as a hot melt agent, a film, or a weather-resistant adhesive.

The sealant layer 73 is used as a fusion layer when the top cover 42 and the rear cover 43 are thermally fused later. For this reason, a resin material having good adhesion to the top cover 42 and the rear cover 43 is selected. Further, it also has a cushion function when the hard laminate film 41 is bonded to the battery 50.
That is, when the soft laminate film 57 and the hard laminate film 41, which are the exterior materials of the battery 50, are heat-sealed through the heat-bonding layer 74, the laminate films each have a fine unevenness on the surface. May not be good. By providing the sealant layer 73 having a thickness of about 25 to 50 μm, the sealant layer 73 serves as a cushion, and the laminate films having fine irregularities on the surface can be bonded well.

Here, the joining state of the soft exterior material and the hard exterior material that characterize the present invention will be described.
As described above, in the battery pack of the present invention, the soft exterior material and the hard exterior material are joined by melting the exterior layer of the soft exterior material and melting the adhesive layer of the hard exterior material, that is, Specifically, the soft laminate film 57 and the hard laminate film 41 are bonded to each other, but the exterior layer 62 of the soft laminate film 57 is not melted, and the heat adhesive layer (the sealant layer 73+ of the hard laminate film 41). The adhesive layer 74) is in a melted state.

By realizing such a joining state, when the battery pack receives an impact due to dropping or the like, and the peeling stress is excessively applied between the hard laminate film 57 and the soft laminate film 41, the soft laminate film 41 is stretched. Therefore, the strength can be increased to the extent that the hard laminate film 57 is removed before pinholes or tears occur. Further, even when light stress is applied, the hard laminate film 57 is integrated with the battery element by the atmospheric pressure and the tensile strength of the soft laminate film 41, and can withstand deformation.
As a result, the battery pack of the present invention has appropriate strength, and can be continuously used without causing defects in the pack appearance when the soft exterior material is not damaged, and the soft exterior material is damaged. It is possible to visually recognize that the hard exterior is peeled off or detached preferentially when it falls, so that it cannot be used, so a battery pack that can prevent the generation of gas due to breakage of the soft exterior and the expansion of the battery that destroys the device can be prevented. It is realized.

Next, the relationship between the soft exterior material and the hard exterior material that can realize the above-described bonded state will be described.
First, when joining the same kind of materials to each other, generally the strength can be increased, and when different materials are used, the strength can be reduced to a certain level or less.
It is also possible to control the adhesive strength to a predetermined level or less by selecting a material that melts at a temperature lower than the melting temperature of the bonding target as the thermal bonding layer and setting the temperature at which the bonding target does not melt.

  In the present invention, these technologies are combined, the material of the exterior layer of the soft exterior material is made of heat resistant material such as nylon, and is a non-stretched material that is different from nylon that exhibits adhesive strength by melting at a temperature at which nylon does not melt It is important to arrange a material such as polypropylene or EVA as a heat-adhesive layer for a hard exterior material. As described above, when a peeling stress is excessively applied between these layers such as when the battery pack is dropped, a soft exterior material is used. Before the laminate film is stretched to reach pinholes or tears, the strength is such that the hard exterior material can be removed.

  From the above, in the present invention, a stretched resin in which the exterior layer of the soft exterior material is different from the thermal adhesive layer of the hard exterior material, and the resin material according to polyolefin, polyamide, polyimide, polyester, or a combination thereof is stretched. Are preferably used alone or in combination.

Note that, when different materials or only one material is melted, the difference between the temperature at which bonding starts and the temperature at which both materials melt tends to narrow. This is because, as long as the battery itself is a heat sink and the battery keeps taking heat away, it is difficult to maintain the molten heat bonding layer at a constant temperature.
The same applies when the temperature of the heater is adjusted in manufacturing the battery pack.
In order to keep the seal interface at an ideal temperature during joining, it is necessary to realize sufficiently fast heat transfer from the heating part to the seal interface, and after the interface, heat transfer is somewhat slow so that heat can be stored easily. It is preferable to do.

In the present invention, it is preferable that the thermal conductivity per area in the state in which the exterior layer and the metal layer of the hard exterior material are laminated is set to 1000 Wm ⁻² K ⁻¹ or more. Can be supplied.
In addition, a material having a thermal conductivity of 1 or less on the battery element side of the sealing interface, that is, the interface between the heat adhesion layer of the hard exterior material and the exterior layer of the soft exterior material, with respect to the heat source used for bonding, specifically heat welding. By disposing, the seal interface can be maintained at a constant temperature.
Especially, since the heat conduction of the exterior layer of the hard exterior material is not good, the heat conduction amount per area is selected with an outer layer having a thickness of 1050 Wm ^-2 K ^-1 or more as a guideline with a thickness of 100 µm or less, and the heat conduction amount per area It is desirable to select a hard metal layer having a thickness of 50000 Wm ⁻² K ⁻¹ or more with a thickness of 330 μm or less as a guide and combining them.

As described above, in the present invention, polyamide (stretched 6 nylon, etc.), polyester (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate), polyolefin (stretched) are used as materials constituting the exterior layer of the hard exterior material. It is preferable to use polypropylene, stretched polyethylene, etc.).
In addition, on the battery element side from the seal interface, it is easier to adjust the amount of heat at the seal interface by setting the exterior layer of the soft exterior material to a thermal conductivity of 1 or less. In addition, it is preferable to select a material having a melting temperature higher than that of heat bonding of the hard exterior material as the exterior layer of the soft exterior material.

Examples of the material constituting the exterior layer of such a soft exterior material include polyamide (stretched 6 nylon, etc.), polyester (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate), polyolefin (stretched polypropylene, stretched polyethylene, etc.). Is preferred.
By performing the selection as described above, in the present invention, adhesion and integration between the soft exterior material, the hard exterior material, and the composite layer thereof are realized.

Here, the manufacturing method of the battery assembly will be described with reference to the drawings again. The exterior material composed of the hard laminate film 41 as described above is bonded to the battery 50.
First, as shown in FIG. 10A, the hard laminate film 41 is bent so as to enclose the battery 50 so that the end portions of the hard laminate film 41 are aligned with the upper surface of the battery 50.
Next, a heater block is applied from the upper surface and the bottom surface of the battery 50, and heating is performed while pressing at a temperature at which the resin material of the thermal bonding layer 74 is melted. The resin material melts to become an adhesive, and bonds the hard laminate film 41 and the battery 50 together. At this time, the exterior layer 62 of the soft laminate film 57 is prevented from melting. Thereby, the battery assembly 45 whose cross section is shown in FIG. 10B is manufactured.

Although the temperature of the heater block varies depending on the resin material of the thermal adhesive layer 74, the temperature is equal to or higher than the melting temperature of the resin material of the thermal adhesive layer and is lower than the melting temperature of the material constituting the exterior layer 62 of the soft laminate film 57. To do. As a result, the resin material constituting the exterior layer 62 of the soft laminate film 57 can be bonded without melting.
In addition, although it can join or adhere | attach also with an adhesive etc., the direction to which heat | fever applied can make the tolerance with respect to such peeling stress continuously high.

Moreover, when heating temperature exceeds 120 degreeC, it is possible to influence a battery element.
For example, polyethylene (PE) is often used as the separator used in the battery element, but since the melting point of PE is about 120 ° C., it is considered that safety and battery function are lowered. Thus, the heater block is heated to an upper limit of about 110 ° C.

As described above, in the present embodiment, deaeration is performed when the battery element 59 is sealed in the soft laminate film 57. As a result, the space between the electrode and the separator is fixed by the force of atmospheric pressure. The entire battery element 59 is structured to have a sense of unity.
Furthermore, by connecting the electrode and the separator with a solid non-aqueous electrolyte, it is possible to reinforce the structure in which a phenomenon such as winding deviation or stacking deviation of the battery element hardly occurs against the impact of dropping.

Further, by deaeration when sealing these elements, the soft laminate film 57 is fixed in close contact with the battery element 59 by atmospheric pressure, and has higher resistance to external stress than when the element is alone.
Further, in this embodiment, the soft laminate film and the hard laminate film can be bonded with an adhesive strength stronger than atmospheric pressure, and since it overcomes the atmosphere, there is a peeling load that causes the soft laminate film to lift from the battery element. Under conditions that do not cover the hard laminate film, the hard laminate film is also integrated with the soft laminate film and the battery element by atmospheric pressure, and can function as a battery pack housing that is resistant to buckling during a light drop.

In addition, a hard laminate film is good also as not only a structure as shown in FIG. 10 but a structure as shown in FIGS.
It is the same that the thermal adhesive layer 74 of the hard laminate film is melted and the outer layer 62 of the soft laminate film is not melted.

  11A and 11B show a configuration in which the hard laminate film 41 is provided so as to cover the bottom surface portion of the battery 50 to form the battery assembly 45, and the joint of the hard laminate film 41 is provided on the upper surface portion of the battery assembly 45. . The battery assembly in FIG. 10 is molded so that the side portions are rounded, whereas the battery assembly in FIG. 11 has a substantially rectangular cross section.

  12A and 12B show a configuration in which the hard laminate film 41 is provided so as to cover one side portion of the battery 50 to form the battery assembly 45, and the hard laminate film 41 is aligned with one side portion of the battery assembly 45. Eyes are provided.

  13A and 13B show a configuration in which two hard laminate films 41 are provided so as to cover both side portions of the battery 50 to form a battery assembly 45, and the hard laminate film is formed on the upper surface portion and the bottom surface portion of the battery assembly 45. Forty-one seams are provided.

  14A and 14B show a configuration in which two hard laminate films 41 are provided so as to cover the upper surface portion and the bottom surface portion of the battery 50 to form a battery assembly 45, and hard laminates are formed on both side portions of the battery assembly 45. A seam of the film 41 is provided.

  15A and 15B show a configuration in which the battery assembly 45 is formed by bending the hard laminate film 41 so as to wrap the bottom portion of the battery 50. 15B is a cross-sectional view of the battery assembly 45 as viewed from the side.

[Production of battery pack]
Next, the circuit board 44 is connected to the positive terminal 55a and the negative terminal 55b (see FIG. 3).
The positive electrode terminal 55a and the negative electrode terminal 55b led out from the top part of the battery assembly 45 molded into a predetermined shape and the protection circuit mounted in advance on the circuit board 44 are fixed by resistance welding, ultrasonic welding or the like.
The circuit board 44 connected to the battery element 59 is inserted into a top cover 42 formed by fitting a pre-molded upper holder 42a and lower holder 42b.

  The circuit board 44 is mounted with a protection circuit including a temperature protection element such as a fuse, PTC, and thermistor, an ID for identifying the battery pack, a resistor, and the like, and a plurality of contact portions. The protection circuit is also applied to a protection circuit including an IC for monitoring a secondary battery and controlling a field effect transistor (FET) and a charge / discharge control FET.

The PTC element is connected in series with the battery element, and when the temperature of the battery becomes higher than the set temperature, the electrical resistance increases rapidly and substantially interrupts the current flowing through the battery. A fuse and a thermistor are also connected in series with the battery element, and when the temperature of the battery becomes higher than the set temperature, the current flowing through the battery is cut off.
In addition, ICs that monitor secondary batteries and control FETs, and protection circuits that include charge / discharge control FETs, can generate heat and fire when the secondary battery terminal voltage exceeds 4.3V to 4.4V. Therefore, if the voltage of the secondary battery exceeds 4.3V to 4.4V, the charge control FET is turned off and charging is prohibited.
Furthermore, if the secondary battery terminal voltage is overdischarged to below the discharge prohibition voltage and the secondary battery voltage becomes 0V, the secondary battery may be shorted internally and cannot be recharged. If it is monitored and falls below the discharge inhibition voltage, the discharge control FET is turned off to inhibit discharge.

The circuit board 44 joined to the battery assembly 45 is covered with an upper holder 42a and a lower holder 42b that are previously molded by injection molding from above and below, and is accommodated in the top cover 42 by fitting the lower holder 42b to the upper holder 42a. The
Next, the direction of the top cover 42 is changed so that the lower holder 42b is close to the battery assembly 45, and the positive electrode terminal 55a and the negative electrode terminal 55b are bent in the battery assembly 45 so that the top portion of the battery assembly 45 is bent. The top cover 42 is fitted into the opening.

  Next, the fitting portion between the top cover 42 and the battery assembly 45 is heated by the heater head, and the top cover 42 and the battery assembly 45 are heat-sealed. At this time, the temperature of the heater head is higher than that at the time of forming the battery assembly and is equal to or higher than the melting temperature of the resin material of the sealant layer 73, and the top cover 42 is bonded to the sealant layer 73 instead of the heat bonding layer 74.

The heat bonding layer 74 heated when the hard laminate film 41 and the battery 50 are bonded is pressed by the top cover 42 when the top cover 42 is fitted, and moves to the back of the battery assembly 45.
As described above, since the resin material having a lower melting temperature than the sealant layer 73 is used for the thermal adhesive layer 74, only the thermal adhesive layer 74 is attached when the hard laminate film 41 and the battery 50 are bonded. It will melt. For this reason, the thermal bonding layer 74 can be moved without moving the sealant layer 73 used for bonding to the top cover 42, and the sealant layer 73 can be exposed.

At this time, an adhesive or a warmed resin material (hot melt resin) may be injected into the gap between the battery 50 and the top cover 42 as necessary. In this case, the top cover 42 is previously provided with an adhesive / hot melt resin inlet.
By injecting the adhesive or the hot melt resin, the adhesion between the battery assembly 45 and the top cover 42 is further improved. However, when hot-melt resin is injected, it is necessary to take measures so that the circuit board 44 is not deformed or damaged by heat.

  Subsequently, the rear cover 43 is fitted to the bottom portion of the battery assembly 45, and the fitting portion between the rear cover 43 and the battery assembly 45 is heated by the heater head, so that the rear cover 43 and the battery assembly 45 are heat-sealed. Also in this case, as in the case of the top cover 42, when the rear cover 43 is fitted, the thermal adhesive layer 74 is pushed by the rear cover 43 and moves to the back of the battery assembly 45, and the exposed sealant layer 73 and the rear cover 43 are removed. Glued.

  At this time, as in the case of the top cover 42, an adhesive or hot melt resin may be injected into the gap between the battery 50 and the rear cover 43 as necessary. Also in this case, an inlet for an adhesive / hot melt resin is provided in the rear cover 43 in advance. Further, the fitting of the top cover 42 and the rear cover 43 and the heat fusion process may be performed simultaneously.

  For the rear cover 43, not only a pre-molded member is used, but a method of molding the battery assembly 45 integrally with the battery assembly 45 by placing the battery assembly 45 in a mold and pouring hot melt resin into the bottom portion is used. It is also possible.

  As described above, the resin material having good adhesiveness with the top cover 42 and the rear cover 43 is provided as the sealant layer 73 on the inner side of the metal foil 71, and further, the adhesiveness with the exterior layer 62 of the hard laminate film 41 is provided on the inner side of the sealant layer 73. The battery 50 and the hard laminate film 41, the battery assembly 45, the top cover 42, and the rear cover 43 can be bonded well by providing the heat bonding layer 74 using a resin material having a lower melting temperature than the sealant layer 73. Can do. For this reason, it becomes the battery pack 40 structure which is hard to be damaged.

  Finally, by sticking a product label so as to cover the joint portion of the hard laminate film 41 generated in a part of the battery pack 45, a battery pack 40 as shown in FIG. 2 is obtained. The product label 46 may be provided as necessary.

Further, instead of providing the product label 46, a method of performing printing, baking coating or the like on the hard laminate film 41 itself may be used. For example, as shown in FIG. 16, a print layer 77 for printing a desired pattern, characters, etc. is provided on the inner surface (metal foil side surface) of the exterior layer 72 of the hard laminate film 41 so that printing can be seen through the exterior layer 72. May be.
In this case, symbols, characters, etc. are printed in reverse. In addition, as shown in FIG. 17, the outer surface of the metal foil 71 may be baked with a laser or the like 78. In this case, the metal foil 71 to which the baking coating 78 is applied can be exposed without providing the outer layer 72 of the hard laminate film and the adhesive layer for bonding the outer layer 72 and the metal foil 71.

  By producing the battery pack 40 in this manner, the external impact strength of the battery pack 40 can be ensured.

  In addition, by using a metal material such as a hard laminate film for the exterior, even in the case of a laminate exterior battery, the heat generation part at the time of nail penetration becomes the battery surface, and the heat dissipation is promoted, so the heat generation inside the battery is suppressed. be able to. For this reason, a safer battery pack can be provided.

(Embodiment 2)
In Embodiment 2, a battery pack using a three-layer hard laminate film as an exterior material will be described.
The pack configuration of the battery pack according to the present embodiment is the same as that of the above-described first embodiment shown in FIGS. Further, the battery element and the battery are the same as those in the first embodiment, and thus the description thereof is omitted.

[Production of battery assembly]
The battery 50 is packaged with a three-layer hard laminate film 80 shown in FIG. 18 to produce a battery assembly. First, the configuration of the hard laminate film 80 will be described.

As shown in FIG. 18, the hard laminate film 80 according to the second embodiment has moisture resistance and insulating properties, in which the metal foil denoted by reference numeral 81 is sandwiched between an exterior layer 82 made of a resin film and a thermal bonding layer 83. It consists of a multilayer film.
In addition, as the metal foil 81 and the exterior layer 82, the same material as in the first embodiment can be used.

The thermal bonding layer 83 is for bonding the battery 50 and the hard laminate film 80 covered with the soft laminate film 57 without providing a separate bonding member.
In the second embodiment, the reactivity is excellent in adhesiveness with each of the resin such as Ny, PET, and PEN that is the outer layer 62 of the battery 50 and the resin such as PP that is the material of the top cover 42 and the rear cover 43. By using a rich material as the thermal bonding layer 83, the battery pack can be configured without providing the sealant layer 73 provided in the first embodiment.

  Specific examples of such materials include acid-modified polypropylene, ionomer resins, ethylene vinyl acetate copolymers, ethylene acrylic acid copolymers, ethyl acrylate copolymers, methyl acrylate copolymers, methacrylic acid copolymers, methyl methacrylate copolymers, polyacrylonitrile. , Ethylene vinyl alcohol resin, polyamide, polyester, and the like can be used, and acid-modified polypropylene, ionomer resin, and ethylene vinyl alcohol resin are particularly preferable. These materials can be used as a hot melt agent, a film, or a weather-resistant adhesive.

  In the hard laminate film 80 in the second embodiment, the thermal adhesive layer 83 is provided with a thickness of about 25 to 50 μm. Further, the metal foil 81 and the exterior layer 82 may have the same thickness as that of the first embodiment. Although the thickness of the thermal adhesive layer 74 of the hard laminate film 41 in the first embodiment is 1 to 5 μm, in the second embodiment, the thermal adhesive layer 83 is made thick so that the thermal adhesive layer 83 itself has a cushioning property. It has a high adhesion.

An exterior material made of such a hard laminate film 80 is bonded to the battery 50. Similarly to the first embodiment, the hard laminate film 80 is bent so as to enclose the battery 50 so that the end of the hard laminate film 80 is aligned with the upper surface of the battery 50.
Next, a heater block is applied from the top and bottom surfaces of the battery 50 to heat and pressurize at a temperature at which the resin material of the thermal bonding layer 83 is melted. The resin material melts to become an adhesive, and bonds the hard laminate film 80 and the battery 50 together. At this time, the outer layer 62 of the soft laminate film is prevented from melting as in the first embodiment. Thereby, the battery assembly 90 is produced.

  Although the temperature of the heater block varies depending on the resin material of the thermal bonding layer, it may be higher than the melting temperature of the resin material of the thermal bonding layer 83. In addition, when the heating temperature exceeds 120 ° C., it is considered that the battery element 59 is affected. From such a viewpoint, it is desirable to heat the heater block with an upper limit of about 110 ° C.

[Production of battery pack]
Next, the circuit board 44 is connected to the positive terminal 55a and the negative terminal 55b. The method for connecting the circuit board 44, the positive terminal 55a, the negative terminal 55b, and the circuit board 44 is the same as that in the first embodiment, and thus the description thereof is omitted.

The top cover 42 in which the circuit board 44 is accommodated is fitted into the top side opening of the battery assembly 90. Next, the fitting portion of the top cover 42 is heated by the heater head, and the top cover 42 and the battery assembly 90 are heat-sealed.
In the present embodiment, since a resin material excellent in adhesiveness to the top cover 42 and the rear cover 43 is used as the resin material for the thermal bonding layer 83, the top cover 42 is bonded to the thermal bonding layer 83. Further, the rear cover 43 can be bonded to the battery assembly 90 in the same manner as the top cover 42.

  At this time, an adhesive or a warmed resin material (hot melt resin) may be injected into the gap between the battery 50 and the top cover 42 as necessary. In this case, an inlet for adhesive and hot melt resin is provided in advance in the top cover and the rear cover. By injecting the adhesive or hot melt resin, the adhesion between the battery assembly 90 and the top cover 42 and the rear cover 43 is further improved. However, when hot-melt resin is injected from the top cover 42, it is necessary to take measures so that the circuit board is not deformed or damaged by heat.

  Further, the rear cover 43 is not only made of a pre-molded member, but may be a method in which the battery assembly 90 is installed in a mold and a hot melt resin is poured into the bottom portion so as to be molded integrally with the battery assembly 90. Is possible.

The battery pack 90 using the three-layered hard laminate film 80 according to the second embodiment as an exterior material has been described above.
In addition to the excellent function when the battery pack of Embodiment 1 has a drop and the like, by appropriately selecting a resin material used for the thermal adhesive layer 83, it is possible to ensure external impact strength without providing a sealant layer, A safer battery pack having sufficient water resistance and heat dissipation can be provided.

(Embodiment 3)
FIG. 19 shows an embodiment of another battery pack of the present invention.
19A to 19C and FIGS. 20A and 20B are schematic diagrams illustrating a configuration in the middle of manufacturing a battery in the battery pack of the present embodiment.

In the present embodiment, a soft laminate film 31 having a recess 31a and a hard laminate film 32 are used, and the battery element 35 is accommodated in the recess 31a, so that the main part of the battery element, that is, the hexahedron battery element 35 is formed. A portion where one main surface is left is covered with a soft laminate film 31 (see FIG. 20).
Next, the hard laminate film 32 is disposed so that the remainder of the battery element 35, that is, one main surface of the battery element 35 typically covers the opening of the recess 31a, and the soft laminate film 31 and the hard laminate film 32 are arranged. The peripheral portion of the overlapped battery element 35 is sealed. At this time, sealing by thermal fusion under reduced pressure is the same as in the first embodiment, and the battery element 35 is in close contact with the soft laminate film 31 and the hard laminate film 32 by thermal fusion under reduced pressure. To do.

Further, as shown in FIG. 20B, the hard laminate film 32 and the soft laminate film 31 are molded so as to enclose the battery element 35. In this embodiment, a heat-adhesive resin tape 90 is prepared, and the tape 90 is used. Then, the soft laminate film 31 is placed and melted between the folded outer layer of the soft laminate film 31 and the outer layer of the soft laminate film 31 covering the battery element 35, and these soft laminate films are bonded to each other.
At the same time, the thermal adhesive layer of the hard laminate film 32 is melted and adhered to the folded soft laminate film 31. At this time, the outer layer of the soft laminate film 31 is prevented from melting as in the first embodiment. Of course, a base material may be present in the thermoadhesive resin tape 90.

  Next, by providing a circuit board (not shown) and a resin molding cover, the battery pack 30 having the hard laminate film 32 as the outermost package can be produced. Such a battery pack has a high volumetric efficiency and realizes a high battery strength, and also has an excellent function when the battery pack of Embodiment 1 is dropped.

(Embodiment 4)
FIG. 21 is a cross-sectional view showing another embodiment of the battery pack of the present invention and showing the state of the manufacturing process.
The battery pack of this embodiment also has the same configuration as that of the battery pack of Embodiment 3, but both sides of the soft laminate film 31 are shortened (FIG. 21A).

  As in the third embodiment, the battery element 35 is sealed at the periphery, and then the hard laminate film 32 and the soft laminate film 31 are molded so as to enclose the battery element 35 as shown in FIG. 21B. In the embodiment, a heat-adhesive resin tape 90 is prepared, and the tape 90 is disposed between the folded outer layer of the hard laminate film 32 and the outer layer of the soft laminate film 31 covering the battery element 35. To melt and bond the two films together. At this time, the outer layer of the hard laminate film 32 is melted while the outer layer of the soft laminate film 31 is not melted as in the first embodiment. Of course, a base material may be present in the thermoadhesive resin tape 90.

The battery pack of this embodiment also has an excellent function when the battery pack of Embodiment 1 is dropped.
In the present embodiment, a so-called double-sided tape can be used instead of the heat-adhesive resin tape 90. In this case, bonding at a low temperature is possible.

(Embodiment 5)
FIG. 22 is a cross-sectional view showing still another embodiment of another battery pack of the present invention and showing the state of the manufacturing process.
The battery pack of this embodiment also has the same configuration as the battery pack of Embodiment 3, but both sides of the soft laminate film 31 are shortened (FIG. 22A).

  As in the third embodiment, the battery element 35 is sealed at the periphery, and then, as shown in FIG. 22B, the hard laminate film 32 and the soft laminate film 31 are molded so as to enclose the battery element 35. In the embodiment, the heat bonding layer of the folded hard laminate film 32 is melted, and the outer layer of the soft laminate film 31 covering the battery element 35 is bonded. At this time, as in the first embodiment, the thermal adhesive layer of the hard laminate film 32 is melted while the outer layer of the soft laminate film 31 is not melted.

The battery pack of this embodiment also has an excellent function when the battery pack of Embodiment 1 is dropped.
In the present embodiment, an acrylic ester-based, silicone-based, latex-based adhesive or the like is provided between the folded outer layer of the hard laminate film 32 and the outer layer of the soft laminate film 31 covering the battery element 35. In this case, adhesion at a low temperature is possible.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

(Examples 1-1 to 23-5, Comparative Examples 1 and 2)
The battery packs having the specifications shown in Tables 1 to 4 below were produced by the operations described above. The obtained battery packs of the respective examples were subjected to the following performance evaluation, and the obtained results are shown in Tables 5 to 8.

(A) Drop test 1
After dropping the battery pack of each Example and Comparative Example from a height of 1.5 m 10 times in a free posture, confirm whether it can be loaded into a portable device without a sense of incongruity, or can be charged and used without functional deterioration did. Both the element of the power generation element and the exterior design must be of a height that does not inherently follow damage, and must be usable as a pack.

(B) Drop test 2
The battery pack of each example and comparative example cannot be loaded into a portable device after dropping in a free posture from a height of 10 m. Do not damage the battery element. No damage to the battery exterior. Confirm.
As long as outside air does not enter the battery by design, no damage will occur. The exterior can be damaged. The pack housing is required to absorb the impact and protect the element from the impact.
In this test, even if the battery pack was unusable, the battery main body and the battery outer case were acceptable, and the battery main body and the battery outer case were acceptable.

The specifications of the battery packs of Examples and Comparative Examples shown in Tables 1 to 4 will be briefly described.
Example 1 group employs various material types for the hard exterior material. Also, Example 2 employs various material types for the metal layer of the hard exterior material in Example 1-1, and Example 3 increases the thickness of the exterior layer of the hard exterior material in Example 1-6. In Example 4, the metal layer of the hard exterior material in Example 3 was made of stainless steel to increase the thickness, and in Example 5 group, various materials were applied to the adhesive layer of the hard exterior material in Example 1-1. (See Table 1).

On the other hand, Comparative Example 1 was obtained by melting both the exterior layer of the soft exterior material and the adhesive layer of the hard exterior material, but it could be attached to the device as a battery pack after a 10 m drop test. The material was stretched and damaged, and the battery pack swelled in the equipment at a later date (see Table 5).
In Comparative Example 2, the battery element is sealed without detaching the inside of the soft exterior material, but the adhesion between the battery element and the soft exterior material is insufficient, and the battery element Lacked a sense of unity with the soft exterior material, deformed due to insufficient strength during a 1.5 m drop test, and could not be attached to equipment. Also, during the 10 m drop test, both the battery element and the exterior material were damaged, causing heat generation and gas generation (see Table 5).

  In Example 7, the composite layer was formed by applying various material types to the exterior layer of the hard exterior material. Example 8 group was the metal layer of the hard exterior material in Example 7-1, and the soft exterior material. In Example 9 group, the thickness of the metal layer of the hard exterior material in Example 7-1 is set to 300 μm, and the total thickness of the metal layers is set to 335 μm. Example 10 group was obtained by applying various materials to the composite layer and the adhesive tape in Example 7-1. Example 11 group was produced by applying various materials to the exterior layer of the soft exterior material in Example 7-1. (See Table 2).

  Moreover, in Table 3, Example 12 group applied various material types to the exterior layer of the hard exterior material, and Example 13 group applied various material types to the metal layer of the hard exterior material in Example 12-1. What was applied, Example 14 was obtained by increasing the thickness of the exterior layer of the hard exterior material in Example 12-6, Example 15 was obtained by increasing the thickness of the metal layer of the hard exterior material in Example 14, Example Group 16 is obtained by applying various material types to the adhesive tape in Example 12-1, and Example 17 group is obtained by applying various material types to the exterior layer of the soft exterior material in Example 12-1.

  Furthermore, in Table 4, Example 18 group applied various material types to the exterior layer of the hard exterior material, and Example 19 group applied various material types to the metal layer of the hard exterior material in Example 18-1. What was applied, Example 20 was obtained by increasing the thickness of the exterior layer of the hard exterior material in Example 18-6, Example 21 was obtained by increasing the thickness of the metal layer of the hard exterior material in Example 20, Example Group 22 applied various material types to the adhesive layer of the hard exterior material in Example 18-1, and Example 23 group applied various material types to the exterior layer of the soft exterior material in Example 18-1. Is.

From Tables 5 to 8, it can be seen that the battery packs of the respective examples can be used without any defects in the battery, the battery exterior, and the battery pack in the 1.5 m drop test.
In each of the battery packs of each example, the exterior of the battery pack was deformed and could not be used in the 10-m drop test, but the battery body and the exterior were not defective and there was no phenomenon such as gas generation.

DESCRIPTION OF SYMBOLS 1 ... Battery, 2a ... Positive electrode terminal, 2b ... Negative electrode terminal, 31 ... Soft laminate film, 32 ... Hard laminate film, 35 ... Battery element, 40 ... Battery pack, 41, 80 ... Hard laminate film, 42 ... Top cover, 42a ... Upper holder, 42b ... Lower holder, 43 ... Rear cover, 44 ... Circuit board, 45 ... Battery assembly, 46 ... Product label, 50 ... Battery, 51 ... Positive electrode, 52 ... Negative electrode, 53a, 53b ... Separator, 55a ... Positive terminal, 55b ... Negative terminal, 57 ... Soft laminate film, 57a ... Recess, 59 ... Battery element, 61, 71, 81 ... Metal layer, 62, 72, 82 ... Exterior layer, 63, 73 ... Sealant layer, 64, 65, 75, 76, 84, 85 ... adhesive layer, 74 ... adhesive layer, 83 ... thermal adhesive layer, 77 ... printed layer, 78 ... baking finish, 90 ... Thermal adhesive resin tape

Claims (9)

A battery element comprising a positive electrode and a negative electrode wound or laminated via a separator, and having a non-aqueous electrolyte composition;
A soft exterior material comprising a laminate film having a structure in which a thermal adhesive layer, a metal layer and an exterior layer are sequentially laminated, and exteriors the main part of the battery element;
A laminate film having a three-layer structure in which a thermal adhesive layer, a metal layer, and an exterior layer are sequentially laminated, and a hard exterior material that sheathes the remainder of the battery element and the soft exterior material;
An adhesive member;
A non-aqueous electrolyte secondary formed by sealing the battery element by bonding the soft exterior material and the hard exterior material along the periphery of the battery element while the electrode terminals of the positive electrode and the negative electrode are led out to the outside. Battery,
A protective circuit board accommodated in the hard exterior material and capable of controlling the voltage and current of the non-aqueous electrolyte secondary battery,
The battery element and the soft exterior material are in close contact,
In the peripheral part of the battery element, the soft exterior material and the hard exterior material are joined by melting the thermal adhesive layer of the soft exterior material and the thermal adhesive layer of the hard exterior material facing each other,
The exterior layer of the soft exterior material has a thermal conductivity of ¹ Wm ⁻¹ K ⁻¹ or less and a melting temperature higher than the thermal adhesive layer of the hard exterior material,
The hard exterior material is folded back so as to enclose the battery element, and the end of the folded hard exterior material and the surface of the soft exterior material covering the main part of the battery element are formed of the soft exterior material. A battery pack that is bonded by melting an exterior layer and melting the adhesive member. The hard exterior material and the soft exterior material are thermally welded,
The heat-adhesive layer of the hard exterior material is an ethylene vinyl acetate copolymer, an ethylene acrylic acid copolymer, an ethyl acrylate copolymer, a methyl acrylate copolymer, a methacrylic acid copolymer, a methyl methacrylate copolymer, polyacrylonitrile, an ethylene vinyl alcohol resin, a polyamide resin, The battery pack according to claim 1, wherein the battery pack is a layer composed of at least one resin selected from the group consisting of a polyester resin, an acid-modified polypropylene, and an ionomer.   The battery pack according to claim 1, wherein the thermal adhesive layer of the soft exterior material is made of unstretched polypropylene and / or unstretched polyethylene.   The soft outer sheathing layer is a stretched resin obtained by stretching at least one resin material selected from the group consisting of polyolefin, polyamide, polyimide and polyester, which is a material different from the thermal adhesive layer of the hard sheathing material. The battery pack according to claim 1, wherein these are singly or in combination. 2. The battery pack according to claim 1, wherein a heat transfer coefficient of a layer obtained by laminating the exterior layer and the metal layer in the hard exterior material is 1000 Wm ⁻² K ⁻¹ or more. The rigid covering member has a heat transfer coefficient 50000Wm ^-2 K ^-1 or more metal layers, battery pack according to claim 1, the heat transfer rate comprises a combination of 1050Wm ^-2 K ^-1 or more outer layers.   The metal layer of the hard exterior material is at least one metal selected from the group consisting of aluminum, copper, iron, stainless steel and nickel, or at least one metal selected from the group consisting of tin, zinc and nickel The battery pack according to claim 1, which is made of plated iron and has a thickness of 330 μm or less.   The battery pack according to claim 1, wherein the exterior layer of the hard exterior material is made of polyamide, polyester, or polyolefin and has a thickness of 115 μm or less.   9. The nylon according to claim 8, wherein the polyamide is stretched 6 nylon, the polyester is at least one resin selected from the group consisting of polybutylene terephthalate, polyethylene terephthalate and polyethylene naphthalate, and the polyolefin is stretched polypropylene or stretched polyethylene. Battery pack.

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