JP5725113B2 - Battery pack and film-covered electrical device - Google Patents

Description

The present invention relates to an assembled battery and a film-clad electrical device .

  In recent years, batteries as power sources for portable devices and the like are strongly required to be light and thin. Therefore, with regard to battery exterior materials, instead of metal cans that are limited in weight and thickness, exterior materials that can be further reduced in weight and thickness, and can adopt a free shape compared to metal cans. As described above, a film using a metal thin film or a laminate film obtained by laminating a metal thin film and a heat-fusible resin film has come to be used.

  As a typical example of a laminate film used for a battery exterior material, a heat-sealable resin film as a heat seal layer is laminated on one surface of an aluminum thin film as a metal thin film, and a protective film on the other surface. A laminate film in which is laminated.

  In a film-clad battery using a laminate film as a packaging material, generally, a battery element composed of a positive electrode, a negative electrode, an electrolyte, and the like is surrounded by a packaging material so that the heat-fusible resin film is inside, The battery element is hermetically sealed (hereinafter simply referred to as sealing) by heat-sealing the exterior material around the battery element. For example, a polyethylene film or a polypropylene film is used as the heat-fusible resin film, and a nylon film or a polyethylene terephthalate film is used as the protective film, for example. When sealing the battery element, lead terminals are connected to the positive electrode and the negative electrode, respectively, so that the positive electrode and the negative electrode of the battery element are drawn out of the outer packaging material, and the lead terminals protrude from the outer packaging material.

  FIG. 18 shows a schematic plan view of an example of a film-clad battery related to the present invention using a laminate film. FIG. 19 is a partial cross-sectional view taken along the line EE of FIG. In addition, Fig.19 (a) has shown the state before the outer periphery protection tape is affixed.

  Laminate film 100 is a three-layer laminate in which a heat-fusible resin film 104 is laminated on one surface of an aluminum thin film that is metal layer 103 and a protective film 102 is laminated on the other surface. It is a film. The film-clad battery 110 shown in FIG. 18 uses two laminated films 100, ie, an upper laminate 100a and a lower laminate 100b. The heat-fusible resin layers 104 face each other, and the sealing position around the battery element 102 At 108, the battery element 102 is hermetically sealed (hereinafter simply referred to as sealing) by heat-sealing the upper laminate 100a and the lower laminate 100b.

  However, in this state, the metal layer 103 is exposed from each cross section of the upper laminate 100a and the lower laminate 100b as shown in FIG.

  When such a film-clad battery is housed in a metal case and used, it is necessary to prevent the metal layer of the laminate film from contacting the surrounding metal member. In particular, when the design is made to be the minimum size in order to optimize the space efficiency, the sealing portion of the laminate film and the wall surface of the metal case come close to each other. Therefore, an insulation measure between the end face where the metal layer of the film-clad battery is exposed and the metal case is extremely important.

  Therefore, as shown in FIG. 19B, the metal layer exposed portion 103a is covered with the outer peripheral protective tape 101 to take insulation measures.

  As another insulation measure, Patent Document 1 discloses a metal in which a metal layer exposed at an end of a laminate sandwiches a battery by fixing a sealing portion of a laminate film with a resin rivet. A configuration that does not contact the heat sink is disclosed.

  Further, Patent Document 2 has a configuration in which a laminate film having a laminate end portion previously formed on an inclined surface is heat-sealed facing each other, and a metal layer at the laminate end portion is covered with an eluted molten resin. It is disclosed.

JP 2005-123007 A JP 2006-286471 A

  However, the method of preventing the metal layer from being exposed by covering with the outer peripheral protective tape 101 has a problem that the cost of the outer peripheral protective tape 101 and the operation cost for attaching the outer peripheral protective tape 101 are high.

  In addition, the method disclosed in Patent Document 1 is effective when a plurality of batteries are arranged in a parallel direction, but the main surfaces of the plurality of batteries are stacked face to face and close to the sealing portion in the lateral direction. If the wall surface of the metal case exists, it is not effective.

  On the other hand, although the method disclosed in Patent Document 2 prevents the metal layer from being exposed by the resin, the film end cannot be processed into an inclined surface after heat fusion. In general, a film-clad battery is processed into a specified size by cutting an outer shape after the heat sealing step. On the other hand, the method of Patent Document 2 cannot perform external cutting after heat fusion, and may reduce dimensional accuracy.

Accordingly, an object of the present invention is to provide an assembled battery and a film-covered electric device that have improved dimensional accuracy and improved insulation characteristics while suppressing manufacturing costs.

In order to achieve the above object, an assembled battery of the present invention is an assembled battery having a plurality of film-clad electrical devices and a metal case that houses the plurality of film-clad electrical devices. An electric device element in which a positive electrode plate and a plurality of negative electrode plates are laminated so as to face each other, a metal layer, a heat-bondable resin layer provided on one surface of the metal layer, and the other metal layer A protective film provided on the surface of the outer cover film, the outer cover film covering the electrical device element by being folded at the folded portion so that the resin layer faces the electrical device element, and the resin A sealing part in which layers are heat-sealed, and a plurality of bent parts formed on one side of a peripheral part of the exterior film, the side opposite to the folded part of the exterior film being rotated a plurality of times in the same rotational direction. Fold It has a plurality of bent portions which are Gaité form, a. In addition, the film-clad electrical device of the present invention includes an electrical device element in which a plurality of positive plates and a plurality of negative plates are laminated to face each other, a metal layer, and a thermal fusion provided on one surface of the metal layer. It is a single exterior film having a resin layer having adhesion and a protective layer provided on the other surface of the metal layer, and the resin layer is folded at the folded portion so as to face the electric device element. In the exterior film covering the electrical device element, a sealing portion in which the resin layers are heat-sealed, and a plurality of bent portions formed on one side of the peripheral portion of the exterior film, the folded portion of the exterior film, Has a plurality of bent portions formed by bending a plurality of opposite sides in the same rotational direction .

  According to the present invention, it was possible to improve the insulation characteristics with high dimensional accuracy while suppressing the manufacturing cost.

It is an external appearance perspective view of the film-clad battery of the 1st Embodiment of this invention. FIG. 2 is a partial cross-sectional view taken along line aa shown in FIG. 1. It is a typical sectional side view of the assembled battery which consists of a some film exterior battery of the state accommodated in the metal case. It is an external appearance perspective view of the film-clad battery of the 2nd Embodiment of this invention. FIG. 5 is a partial cross-sectional view taken along line bb shown in FIG. 4. It is an external appearance perspective view of the film-clad battery of the 3rd Embodiment of this invention. It is a figure which shows the area | region which is heat-sealed between the heat-fusible resin layers in the film-clad battery of the 3rd Embodiment of this invention. FIG. 7 is a partial cross-sectional view taken along line cc shown in FIG. 6. It is an external appearance perspective view of the film-clad battery of the 4th Embodiment of this invention. FIG. 10 is a partial cross-sectional view taken along the line dd shown in FIG. 9. It is an external appearance perspective view of the film-clad battery of the 5th Embodiment of this invention. It is a figure which shows the area | region which is heat-sealed between the heat-fusible resin layers in the film-clad battery of the 5th Embodiment of this invention. It is a top view of the two laminated films used for the film-clad battery of the 5th Embodiment of this invention. FIG. 12 is a partial cross-sectional view taken along line ee and line ff shown in FIG. 11. It is an external appearance perspective view of two types of film-clad batteries used for the assembled battery of the 6th Embodiment of this invention. It is a schematic diagram which shows arrangement | positioning of the cross section of a film at the time of connecting the same kind of film-clad battery in series, and piled up in the thickness direction to make an assembled battery. It is a schematic diagram which shows arrangement | positioning of the cross section of the film at the time of connecting two types of film-clad batteries of the 6th Embodiment of this invention in series, and piled up in the thickness direction to make an assembled battery. It is a typical top view of an example of the film-clad battery relevant to this invention using the laminate film relevant to this invention. It is a partial cross section figure in the EE line | wire of FIG.

  Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is an external perspective view of the film-clad battery of this embodiment. 2 is a partial cross-sectional view taken along line aa shown in FIG.

  The film-clad battery 1 includes a battery element 2, a packaging material that houses the battery element 2 together with an electrolytic solution, and a positive tab 4 a and a negative tab that extend from the laminate films 5 and 6. 4b.

  The battery element 2 is configured by alternately laminating a plurality of positive plates and a plurality of negative plates via separators. As the separator, a porous film formed using a thermoplastic resin such as polyolefin is used.

  Each positive electrode plate has an aluminum foil coated with a positive electrode, and the negative electrode plate has a copper foil coated with a negative electrode. The extension part that is not coated with the electrode material that extends from the laminated region is a relay part in which the extension parts of the positive electrode plates and the extension parts of the negative electrode plate are each ultrasonically welded together. A positive electrode current collector and a negative electrode current collector (not shown) are formed. At the same time, the connection of the positive electrode tab 4a to the positive electrode current collector and the connection of the negative electrode tab 4b to the negative electrode current collector are also ultrasonically welded. In the present specification, the positive electrode tab 4a and the negative electrode tab 4b may be collectively referred to as a tab 4.

  The exterior material is composed of two laminate films 5 (first exterior film) and laminate film 6 (second exterior film) that surround and surround the battery element 2 from both sides in the thickness direction. Each of the laminate films 5 and 6 is formed by laminating protective layers 5a and 6a, metal layers 5b and 6b, and heat-fusible resin layers 5c and 6c having heat-fusibility. The protective layers 5a and 6a and the heat-fusible resin layers 5c and 6c are all resin layers having electrical insulation. As the resin used for the protective layer, a resin having a high melting point such as nylon or polyester can be used. As the heat sealing resin, for example, PP (polypropylene), PE (polyethylene), or acid-modified products thereof can be used. It is preferable that the heat sealing resin has a lower melting point than the resin of the protective layer. The battery element 2 is sealed by heat-sealing the sealing portion 8 which is the heat-sealing portion of the laminate films 5 and 6 so that the heat-fusible resin layer becomes an inner layer of the battery.

  The laminate film 5 is formed with a recess for accommodating the battery element 2. In addition, what is necessary is just to form this recessed part as needed.

  Laminate films 5 and 6 have a winding portion 10 formed by bending the sealing portion 8 on the side where the tab 4 does not extend twice in the same rotational direction. The entrainment portion 10 includes a first bent portion 10a and a second bent portion 10b. The end portion 5d of the laminate film 5 and the end portion 6d of the laminate film 6 are sealed with the laminate films 5 and 6. It is surrounded by part 8.

  In the first bent portion 10a, the sealing portion 8 is bent so that the end portions 5d and 6d face the battery element 2.

In the second bending part 10b, the first bent portion 10a with the bent portion ends 5d than at a position closer to 6d, the edge portion 5d, 6d is the inner peripheral surface 10a ₁ of the first bent portion 10a The sealing portion 8 is bent so as to face.

  Thus, by bending the sealing portion 8 with the first bent portion 10a and the second bent portion 10b, the end portions 5d and 6d are surrounded by the laminate films 5 and 6, and the metal layers 5b and 6b. Is not exposed to the outside.

  In addition, the winding part 10 mentioned above will not be limited to the said structure if it is the structure which can surround the edge parts 5d and 6d with the laminate films 5 and 6. FIG. In the above example, the entrainment portion 10 surrounds the end portions 5d and 6d with the laminate films 5 and 6 by bending the sealing portion 8 of the laminate films 5 and 6 twice in the same rotational direction. In addition, for example, the entrainment part 10 may be formed by bending the laminate films 5 and 6 three times or more. The bending direction and the bending position may be any as long as the end portions 5d and 6d are surrounded by the laminate films 5 and 6. Furthermore, the entrainment part 10 may surround the end parts 5d and 6d with the laminate films 5 and 6 by winding the sealing part 8.

  In FIG. 2, the entrainment portion 10 is disposed on the protective layer 5 a of the laminate film 5, so that the protective layer 5 a and the protective layer 6 a face each other (G portion in FIG. 2), and the protective layers 6 a are Facing each other (H part in the figure). These protective layers 5a and 6a may be heat-sealed or may not be heat-sealed. When not heat-sealing, the end portions 5d and 6d can be reliably surrounded by the laminate films 5 and 6 by firmly pressing and bending the first bent portion 10a and the second bent portion 10b. it can. When heat-sealing, the surroundings of the end portions 5d and 6d by the laminate films 5 and 6 can be made more reliable.

  Further, in the above-described example, the configuration in which the exterior films are two separate laminate films 5 and 6 has been described as an example. However, as illustrated in FIG. The laminate film may be folded at the folding portion 11. When two laminated films 5 and 6 are used, there are two sides where the metal layers 5b and 6b are exposed to the outside except for the side where the tab 4 extends, so that two winding portions 10 are also formed. Will be. On the other hand, when one laminated film is folded, the metal layers 5b and 6b are not exposed to the outside in the folded portion 11, and therefore the entraining portion 10 is on the side opposite to the folded portion 11 that is the side on which the exterior film is folded. It will be formed only on the sides.

  Next, the outline of the manufacturing method of the film-clad battery 1 of this embodiment is demonstrated.

  The battery element 2 is sandwiched between the laminate films 5 and 6 so that the positive electrode tab 4 a and the negative electrode tab 4 b extend from the sealing portion 8. Thereafter, only three sides of the sealing portions 8 on the four sides of the laminate films 5 and 6 are heat-sealed to leave the laminate films 5 and 6 in a bag shape, and an electrolytic solution is injected therein. After injecting the electrolytic solution, the remaining sealing portion 8 is heat-sealed and sealed.

  Next, the winding part 10 is formed in the side where the positive electrode tab 4a and the negative electrode tab 4bg do not extend among the four sides of the laminate films 5 and 6.

  First, on the sealing part 8, the position used as the 1st bending part 10a and the 2nd bending part 10b is decided. As described above, by determining the positions of the first bent portion 10a and the second bent portion 10b in advance, the film-covered battery 1 that is finally completed can have high dimensional accuracy. The 1st bending part 10a is prescribed | regulated on the inner side close | similar to the battery element 2, and the 2nd bending part 10b is prescribed | regulated on the outer side rather than the 1st bending part 10a.

  Next, the laminate films 5 and 6 are bent 180 degrees until the protective layers 5a come into contact with each other at the second bent portion 10b. Next, the laminated films 5 and 6 are bent 180 degrees at the first bent portion 10a until the protective layer 5a of the laminated film 5 and the protective layer 6a of the laminated film 6 come into contact with each other. That is, the sealing part 8 is bent twice in the same rotational direction. In FIG. 2, it is bent twice in the counterclockwise direction. In this manner, the end portions 5d and 6d are surrounded by the laminate films 5 and 6 by bending the sealing portion 8 twice in the same direction.

  Finally, the entraining portion 10 is pressed from above and below by a heater and heated to heat-seal the protective layers 5a and 6a. This step may be omitted as described above.

  Next, FIG. 3 shows a schematic cross-sectional side view of an assembled battery made up of a plurality of film-covered batteries, housed in a metal case. FIG. 3 is a view from the direction in which the tabs 4a and 4b extend. Moreover, since the exterior film of the film-clad battery shown in FIG. 3 is a laminate film folded back, the entrainment portion 10 is provided only on one side.

  A plurality of film-clad batteries 1 are stacked and stored in the metal case 15. The metal case 15 optimizes space efficiency by making the gap between the film-clad battery 1 and the wall surface of the metal case 15 as small as possible. For this reason, the film-clad battery 1 and the wall surface of the metal case 15 are disposed close to each other.

  However, since the end portions 5d and 6d where the metal layers 5b and 6b are exposed are surrounded by the laminate films 5 and 6 of the entrainment portion 10, the metal layers 5b and 6b come into contact with the wall surface of the metal case 15. There is no.

  As described above, according to this embodiment, since the end portions 5d and 6d are insulated, the outer peripheral protective tape is not necessary, and the cost required for the outer peripheral protective tape can be reduced.

  Moreover, the film-clad battery 1 of this embodiment does not perform a heat sealing | fusion process, after cutting the external shape of the laminate films 5 and 6 and adjusting the dimension. Further, the bending at the first bent portion 10a and the second bent portion 10b is bent at a predetermined position. For this reason, the film-clad battery 1 of this embodiment can obtain the film-clad battery 1 with high dimensional accuracy.

  Furthermore, the film-clad battery 1 according to the present embodiment has the end portions 5 d and 6 d surrounded by the entrainment portion 10. For this reason, even if there is only a small gap with the wall surface of the metal case 15, the metal layers 5 b and 6 b do not contact the wall surface of the metal case 15 and can be reliably insulated.

(Second Embodiment)
FIG. 4 is an external perspective view of the film-clad battery of this embodiment. FIG. 5 is a partial cross-sectional view taken along the line bb shown in FIG.

  In addition, the film-clad battery of this embodiment is the same structure as the film-clad battery of 1st Embodiment except the structure of an entrainment part differing from 1st Embodiment. Therefore, detailed description of the same configuration is omitted. In addition, the same components as those of the film-clad battery of the first embodiment will be described using the same reference numerals as those used in the first embodiment.

  The sealing portion 8 includes a first region 8a, a second region 8b, first and second bent portions 20a, 20b, and a third region 8c, and the second region 8b, the first and first regions The winding portion 20 is configured by the two bent portions 20a and 20b and the third region 8c.

  The first region 8 a is formed at a position closest to the battery element 2 in the sealing portion 8. In the first region 8a, the heat-fusible resin layer 5c and the heat-fusible resin layer 6c are heat-fused.

  The second region 8b is formed outside the first region 8a. 4 and 5, the second region 8b is shown as having a space formed between the laminate films 5 and 6 and the third region 8c. However, this shows a space for easy understanding of the configuration of the entrainment unit 20. Actually, as will be described later, when the third region 8c is heat-sealed, the laminate film 5 is heated by pressing the laminate films 5 and 6 with a heater from the vertical direction (Y direction in FIG. 5). The heat-fusible resin layers 5c and the heat-fusible resin layers 6c of the laminate film 6 are heat-sealed.

  The 1st bending part 20a and the 2nd bending part 20b are the parts which bent the 2nd area | region 8b of the laminate films 5 and 6 in the predetermined position. In the first bent portion 20a, the laminate film 5 is bent so that the heat-fusible resin layer 5c is on the inner side and the protective layer 5a is on the outer side. In the second bent portion 20b, the laminate film 6 is bent so that the heat-fusible resin layer 6c is on the inner side and the protective layer 6a is on the outer side.

  The third region 8c is a region between the first and second bent portions 20a and 20b and the end portions 5d and 6d, and the protective layer 5a and the protective layer 6a are heat-sealed. In addition, the protective layer 5a and the protective layer 6a do not need to be heat-sealed.

  The end portions 5 d and 6 d face the battery element 2 and are surrounded by the laminate film 5 and the laminate film 6.

  Next, the outline of the manufacturing method of the film-clad battery 1 of this embodiment is demonstrated.

  The battery element 2 is sandwiched between the laminate films 5 and 6 so that the positive electrode tab 4 a and the negative electrode tab 4 b extend from the sealing portion 8. Thereafter, only three sides of the sealing portions 8 on the four sides of the laminate films 5 and 6 are heat-sealed to leave the laminate films 5 and 6 in a bag shape, and an electrolytic solution is injected therein. After injecting the electrolytic solution, the remaining sealing portion 8 is heat-sealed and sealed.

  Here, the positive electrode tab 4a and the negative electrode tab 4b do not extend, and for the sealing part 8 on the two sides where the entrainment part 20 is formed, only the first region 8a is thermally fused, and the remaining second The region 8b, the bent portions 20a and 20b, and the third region 8c are not thermally fused. Further, the positions to be the first and second bent portions 20a and 20b are determined in advance.

  Next, the laminate film 5 is bent at the first bent portion 20a so that the heat-fusible resin layer 5c is on the inner side and the protective layer 5a is on the outer side. Further, the laminate film 6 is bent at the second bent portion 20b so that the heat-fusible resin layer 6c is on the inner side and the protective layer 6a is on the outer side. Note that this bending step may be performed at a stage before the first region 8a is heat-sealed.

  The protective layer 5a of the laminate film 5 bent at the first bent portion 20a and the protective layer 6a of the laminate film 6 bent at the second bent portion 20b face each other. In this state, the entraining unit 20 is sandwiched and heated from the Y direction by a heater (not shown). Thereby, the heat-fusible resin layers 5c of the laminate film 5 and the heat-fusible resin layers 6c of the laminate film 6 are heat-fused, respectively. Depending on the heating temperature, the protective layer 5a and the protective layer 6a may be heat-sealed. Further, since the bent state is maintained by the deformation of the metal layer, it is not always necessary to heat the entraining portion 20 and to fuse the heat-sealing resins.

  Through the above steps, the metal layers 5b and 6b of the end portions 5d and 6d are surrounded by the laminate films 5 and 6.

  Similarly to the first embodiment, this embodiment also eliminates the need for the outer peripheral protective tape because of the insulation of the end portions 5d, 6d, and can reduce the cost required for the outer peripheral protective tape.

  Moreover, the film-clad battery 1 of this embodiment does not perform a heat sealing | fusion process, after cutting the external shape of the laminate films 5 and 6 and adjusting the dimension. Further, the bending at the bending portion 20a is performed at a predetermined position. For this reason, the film-clad battery 1 of this embodiment can obtain the film-clad battery 1 with high dimensional accuracy.

  Furthermore, the film-clad battery 1 according to the present embodiment has the end portions 5 d and 6 d surrounded by the entrainment portion 10. For this reason, even if there is only a small gap between the metal case 15 and the wall surface, the metal layers 5 b and 6 b do not contact the wall surface of the metal case 15.

(Third embodiment)
FIG. 6 is an external perspective view of the film-clad battery of this embodiment. FIG. 7 is a view showing a region where heat fusion resin layers are heat-sealed in the film-clad battery of this embodiment. FIG. 8 is a partial cross-sectional view taken along line cc shown in FIG.

  This embodiment is different from the above-described embodiments in that only the laminate film 6 is bent. However, except for this point, the configuration is basically the same as that of each of the above-described embodiments. Therefore, in the following description, it demonstrates using the same code | symbol as the above-mentioned embodiment, and shall explain only a different point from the above-mentioned each embodiment.

  The width of the laminate film 6 in the W direction in the drawing is wider than that of the laminate film 5. That is, the film-clad battery 1 shown in FIGS. 6 and 7 has a bent portion 6 e that is bent at both ends of the laminate film 6. The trimming position of the side of the laminate film 6 where the tab 4 does not extend is outside the trimming position of the side of the film 5 in order to form these bent portions 6e. In other words, the laminate film 6 is larger than the laminate film 5 in the dimension in the direction perpendicular to this side (side where the tab 4 extends).

  In addition, on the side where the tab 4 does not extend, a covering portion S is formed in which the end surface 5d where the metal layer 5b of the laminate film 5 is exposed is covered with the bent portion 6e.

  Next, bonding of the laminate film 5 and the laminate film 6 will be described.

  First, the power generation element 2 and the tab 4 are arranged between the laminate film 5 and the laminate film 6.

  Next, in order to form the bending part 6e in the laminate film 6, it arrange | positions mutually so that the part used as the bending part 6e may protrude from the laminate film 5. FIG.

  Next, this protruding portion is bent to form a bent portion 6 e, and the end surface 5 d of the laminate film 5 is covered with the bent portion 6 e of the laminate film 6 to form the covering portion S. In the present embodiment, the heat-fusible resin layers 6c of the bent portion 6e face each other near the base of the bent portion 6e (A portion in FIG. 7 and A portion in FIG. 8). At the tip of the bent portion 6e, the heat-fusible resin layer 6c of the bent portion 6e and the protective layer 5a of the laminate film 5 face each other (the hatched B portion in FIG. 7 and the B portion in FIG. 8). .

  In this state, the peripheral portions of the laminate film 5 and the laminate film 6 facing each other are bonded together by heat sealing. That is, the sealing part 8, A part (second sealing part), and B part (first sealing part) in the peripheral part of the battery element 2 are heated by a heater (not shown). In the sealing part 8, the heat-fusible resin layer 5c of the laminate film 5 and the heat-fusible resin layer 6c of the laminate film 6 are joined by heat fusion. In the A part (second sealing part), the heat-fusible resin layers 6c of the bent part 6e are joined by heat-sealing.

  In the above description, the method of forming the bent portion 6e in advance and then performing heat fusion in a lump after that has been described, but the present invention is not limited to this. For example, first, the sealing portion 8 may be heat-sealed first, then the bent portion 6e may be formed, and the A portion and the B portion may be heat-sealed. The thermal fusion between the A part and the B part may be performed simultaneously or separately.

  In any method, by forming the covering portion S that covers the end surface 5d of the laminate film 5 with the bent portion 6e as described above, it is possible to prevent the metal layer 5b of the end surface 5d from being exposed to the outside, and to have an insulating property. Can be increased. On the other hand, the cross section 6 d where the metal layer 6 b of the bent portion 6 e is exposed faces the battery element 2. That is, the bent portion 6e is bent so that the cross section 6d where the metal layer 6b is exposed faces the inside of the film-clad battery 1. Therefore, even when a plurality of film-clad batteries 1 are arranged so as to be adjacent to each other, or when the film-clad battery 1 is housed in a metal casing, the adjacent film-clad batteries 1 and metal The possibility of electrical contact with the housing is extremely low.

  Further, in the above-described configuration in which the bent portion 6e is folded so as to partially overlap, not only the sealing portion 8 but also the A portion and the B portion are heat-sealed, so only the sealing portion 8 is heat-sealed. It is strongly bonded compared to the part.

  As described above, according to the present embodiment, the metal layer of the laminate film can be prevented from being exposed, and the insulating characteristics can be improved.

(Fourth embodiment)
FIG. 9 is an external perspective view of the film-clad battery of this embodiment. FIG. 10 is a partial cross-sectional view taken along line dd shown in FIG.

  This embodiment is the same as that of the third embodiment except that the bent portion 6e of the laminate film 6 is not provided with an A portion (second sealing portion) in which the heat-fusible resin layers 6c are heat-sealed. It is the same configuration. Therefore, in the following description, the same reference numerals as those in the third embodiment are used, and only differences from the third embodiment are described.

  The film-clad battery 11 of the present embodiment is not provided with the A part on both sides. For this reason, compared with the film-clad battery 1 of 3rd Embodiment, a battery can be reduced in size by the part which does not have A part.

  In part B, the heat-fusible resin layer 6c of the bent part 6e is heat-sealed to the protective layer 5a of the laminate film 5, but an adhesive is applied to increase the bonding force. Also good. Alternatively, in addition to heat fusion, ultrasonic fusion or bonding using only an adhesive may be used.

  The film-clad battery shown in FIGS. 9 and 10 forms the bent portion 6e, so that the laminated film 6 has a trimming position on the side where the tab 4 does not extend outside the trimming position on the side of the film 5. It has become. In other words, the laminate film 6 is larger than the laminate film 5 in the dimension in the direction perpendicular to this side (side where the tab 4 extends). However, the film-clad battery of this embodiment may use the laminate films 5 and 6 having the same trimming position on the side where the tab 4 does not extend.

  As described above, even when the lengths of the laminate films 5 and 6 are the same as in the present embodiment, the metal layer of the laminate film can be prevented from being exposed, and the insulating characteristics can be improved.

(Fifth embodiment)
FIG. 11 is an external perspective view of the film-clad battery of this embodiment. FIG. 12 is a diagram showing a region where heat fusion resin layers in the film-clad battery of the present embodiment are thermally fused together. FIG. 13 is a plan view of two laminated films used for the film-clad battery of this embodiment. 14 is a partial cross-sectional view taken along line ee and line ff shown in FIG.

  The present embodiment has the same configuration as that of the fourth embodiment, except that the laminate film 5 is formed with a notch 5e with a predetermined interval. Therefore, in the following description, the same reference numerals as those in the fourth embodiment are used, and only differences from the fourth embodiment are described.

  As in the fourth embodiment, the film-clad battery 12 of the present embodiment is not provided with the A portion on both sides thereof, that is, on the portions extending from the sealing portion 8. For this reason, compared with the film-clad battery 1 of 3rd Embodiment, a battery can be reduced in size by the part which is not provided and A part is provided.

  Further, as shown in FIGS. 11 and 13A, a plurality of notches 5e are formed on both long sides of the laminate film 5 at a predetermined interval. For this reason, a plurality of A ′ portions (second sealing portions) in which the heat-fusible resin layers 6 c are heat-sealed to the bent portion 6 e of the laminate film 6 in the notch portion 5 e are formed. Therefore, compared with the film-clad battery 11 of 4th Embodiment, joining force can be raised only the part of A 'part.

  In the case of the fourth embodiment, when the bent portion 6e is not sufficiently fixed to the laminate film 5, a springback may be caused. That is, B part joins the heat-fusible resin layer 6c of the bending part 6e with respect to the protective layer 5a of the laminate film 5. FIG. For this reason, if only heat fusion is performed without applying an adhesive or the like, the bonding force is weaker than that of heat fusion between the heat-fusible resin layers. Therefore, in this B part, the bending part 6e may peel off from the laminate film 5, and the front-end | tip part of the bending part 6e may jump up, and what is called a spring back may arise. In such a state, the cross-section 6d where the metal layer 6b of the bent portion 6e is exposed may face upward, and may contact an adjacent battery or a peripheral conductive member.

  However, in the case of the present embodiment, since heat fusion is performed between the heat-fusible resin layers 6c at the A ′ portion in the notch portion 5e, strong bonding is possible, and the adhesive is not applied to the B portion. The occurrence of springback can be prevented.

  By the way, in the case of a film-clad battery, moisture from the outside air tends to enter the battery from between the heat-fusible resin layer 5c and the heat-fusible resin layer 6c. Since the moisture penetration rate is inversely proportional to the length of the path length from the outside air side of the heat-sealed part to the battery internal space side, if the amount of moisture penetration is to be reduced in order to maintain the battery performance, The longer the path length, the better.

  In the ee cross section shown in FIG. 14, moisture from the outside air enters from the end 5e, and the moisture intrusion speed of this portion is determined by the path length from the end 5e to the battery internal space. For this reason, the moisture permeation speed is faster than that of the ff cross section of FIG. 14, but the portion of the ee cross section is only partially formed by the notch. Therefore, as a whole battery, an increase in the moisture infiltration rate can be suppressed as compared with the configuration in which the entire region of the side has the end portion 5e and the A portion. Further, since the effect of preventing the spring back can be sufficiently achieved if the fusion part by the notch part 5e is partially provided, the desired effect can be obtained without substantially increasing the moisture infiltration rate.

  In addition, although the shape of the notch part 5e shown by each figure is a semicircle, a shape is not specifically limited. Further, the number and interval of the notches 5e are not particularly limited as long as the spring back can be prevented while considering the moisture intrusion speed.

  In each of the above-described first to third embodiments, the configuration in which the exterior films are two separate laminate films 5 and 6 has been described as an example, but the laminate films 5 and 6 are one laminate film. It may be configured. In other words, the exterior film may be folded back and the laminate film 5 and the portion facing the laminate film 5 may be the laminate film 6.

(Sixth embodiment)
FIG. 15 is an external perspective view of two types of film-clad batteries used in the assembled battery of this embodiment. FIG. 16 is a schematic diagram for explaining a problem when an assembled battery is configured with one type of film-clad battery. Moreover, the schematic diagram which shows the structure of the assembled battery by two types of film-clad batteries of this embodiment in FIG.

  In the film-clad batteries 13a and 13b of this embodiment, one laminate film 16 is folded in two. And although the bending part 6e is partially provided in this one laminate film 16, since the fundamental structure is the same as that of each embodiment mentioned above, detailed description is abbreviate | omitted. FIG. 15 shows the configuration of the bent portion described in the third embodiment as an example, but the configuration shown in the fourth embodiment or the fifth embodiment is also possible. Good.

  FIG. 16 shows one type of film-clad battery of a type in which one side is folded in two and the bent side is on the opposite side and is stacked with the side with the bent portion facing the same side upside down. As described above, there arises a problem that the cross section 16d may be in electrical contact. On the other hand, when the sides with the bent portions are stacked alternately, the space efficiency obtained by folding in two and reducing the area is lost. Therefore, as described below, this problem can be avoided by using two types of film-clad batteries.

  In this embodiment, two types of film-clad batteries 13a and 13b will be described.

  The difference between the film-clad battery 13a and the film-clad battery 13b is that the positive electrode tab 4a and the negative electrode tab 4b are positioned in different directions as shown in FIG. In the film-clad battery 13a, the positive electrode tab 4a extends on the α side in the figure, and the negative electrode tab 4b extends on the β side in the figure, whereas the film-clad battery 13b has the α in the figure on the contrary. A negative electrode tab 4b extends on the side, and a positive electrode tab 4a extends on the β side in the figure. The film-clad battery 13a and the film-clad battery 13b have the same structure except that the tab polarity is reversed.

  In the present embodiment, a plurality of batteries are connected in series and stacked in the thickness direction to form an assembled battery, but two types of film-covered batteries 13a and film-covered batteries 13b are alternately connected to form an assembled battery. By doing in this way, as shown in FIG. 17, the cross section 16d of the laminate film 16 will be arranged without going to each other. Therefore, the assembled battery of this embodiment can prevent the cross section 16d of the laminate film 16 from being in electrical contact.

  In the embodiment of FIG. 15, the top battery and the second battery have the bending direction of the bent side opposite to the direction in which the positive and negative electrode tabs are pulled out in the manufacturing process. By preparing two types of batteries in this way, when connecting in series, if the direction of the side with the bent part and the direction of the bending are aligned and stacked alternately, the drawn positive and negative tabs alternate. Therefore, the positive electrode tab of one adjacent battery and the negative electrode tab of the other battery can be easily connected at a short distance.

  In the above description, the case of series connection has been described as an example, but the present invention is not limited to this. That is, even when connected in parallel, the film-clad batteries are stacked so that the cross-sections 16d of the laminate film 16 do not face each other, and the cross-sections 16d are prevented from being in electrical contact with each other. can do. Specifically, for example, one type of film-clad battery with one side folded in two and a folded part on the opposite side is stacked with the direction of the side with the folded part aligned and the direction of bending, and connected in parallel. It is obtained by doing.

1, 11, 12, 13a, 13b Film-clad battery 2 Battery element 4 Tab 4a Positive electrode tab 4b Negative electrode tab 5, 6, 16 Laminate film 5a, 6a Protective layer 5b, 6b Metal layer 5c, 6c Thermal adhesive resin layer 5d , 6d End portion 5e Notch portion 6e Bending portion 8 Sealing portion 8a First region 8b Second region 8c Third region 10a ₁ Inner peripheral surface 10, 20 Entraining portion 10a, 20a First bending portion 10b, 20b Second bent portion 11 Folded portion 15 Metal case 16d Cross section S Covering portion

Claims (6)

A battery pack having a plurality of film-clad electrical devices and a metal case that houses the plurality of film-clad electrical devices,
Each film-covered electrical device is
An electrical device element in which a plurality of positive electrode plates and a plurality of negative electrode plates are laminated to face each other;
A single exterior film having a metal layer, a resin layer having heat-fusibility provided on one surface of the metal layer, and a protective layer provided on the other surface of the metal layer, The resin film is folded at the folded portion so as to face the electrical device element, and an exterior film covering the electrical device element,
A sealing part in which the resin layers are heat-sealed;
Wherein a plurality of bent portions formed on one side of the peripheral portion of the exterior film, and the plurality of bent portions formed by bending a plurality of times on the opposite sides in the same direction of rotation and the folded portion of the outer film Having
Assembled battery.   The assembled battery according to claim 1, wherein at least a part of the bent portion is the sealing portion. The assembled battery according to claim 1 or 2 , wherein the plurality of film-clad electrical devices are arranged such that surfaces having the plurality of bent portions face the same direction. The plurality of bent portions include a first bent portion and a second bent portion bent at a position closer to the end surface than the first bent portion, and the first bent portion includes the first bent portion, The assembled battery according to any one of claims 1 to 3, wherein the battery pack is bent so that the second bent portion faces the electric device element covered with the exterior film. Each film-clad electrical device has first and second electrode tabs extending in opposite directions from the electrical device element and having different polarities from each other,
Wherein the plurality of film-covered electrical device, the electrode tabs to each other different polarities are opposed to each other, the assembled battery according to any one of claims 1 4. An electrical device element in which a plurality of positive electrode plates and a plurality of negative electrode plates are laminated to face each other;
A single exterior film having a metal layer, a resin layer having heat-fusibility provided on one surface of the metal layer, and a protective layer provided on the other surface of the metal layer, The resin film is folded at the folded portion so as to face the electrical device element, and an exterior film covering the electrical device element,
A sealing part in which the resin layers are heat-sealed;
Wherein a plurality of bent portions formed on one side of the peripheral portion of the exterior film, and the plurality of bent portions formed by bending a plurality of times on the opposite sides in the same direction of rotation and the folded portion of the outer film , Having a film exterior electrical device.