JP2011175849A - Outer package for electrochemical device, and electrochemical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outer package for an electrochemical device for housing a plurality of power generating elements inside, capable of reducing a dead space and having a sealing structure superior in pressure resistance. <P>SOLUTION: The outer package for the electrochemical device, for housing a plurality of power-generating elements of the electrochemical device inside in a state pinching barrier ribs 7 between each two power-generating elements, is provided with a sealer structured of a pair of laminate films 51, 52 opposed to each other with edges of the pair of laminate films 51, 52 adhered to each other. At least part of the sealer turns to be a built-in sealer 5 housed inside the outer package with edges themselves of the pair of laminate films 51, 52 folded and adhered to an inside of the outer package, and at least parts of the edges folded toward inside of the outer package are extended to structure the barrier ribs 7 above. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exterior body for an electrochemical device and an electrochemical device.

  As electrochemical devices such as batteries and electric double layer capacitors, those using an aluminum laminate outer package have been put into practical use. The aluminum laminate outer package is advantageous in that it is lightweight and has a high degree of freedom in shape.

  The structure of the conventional laminate exterior body has a structure in which a laminate film is sealed by a hot press or the like at an adhesive margin portion provided around the power generation element accommodating portion (see, for example, Patent Documents 1 to 4). Moreover, in an electrochemical device using such a laminate outer package, attempts have been made to insert two or more power generation elements into the outer package for the purpose of increasing the operating voltage (for example, Patent Documents 5 to 6). reference). In this case, since it is necessary to isolate | separate an electric power generation element within an exterior body, providing a partition between electric power generation elements is performed. The structure of the exterior body provided with the partition wall is a structure in which the partition wall and the laminate film are integrated by sandwiching the partition wall with a laminate film at the periphery of the power generation element accommodating portion and sealing with a hot press or the like. Are known.

  However, the above-described structure of the laminate outer package has a problem that a dead space corresponding to the paste margin occurs. For this reason, it has been proposed to save space by folding the adhesive margin part (seal part) of the laminate outer package (see, for example, Patent Documents 7 to 11).

JP 2000-77043 A JP 2000-133216 A JP 2000-149993 A JP 2000-285904 A JP 2006-221938 A JP 2005-79473 A Japanese Patent Laid-Open No. 2000-200585 JP 2000-251855 A JP 2000-268807 A JP 2001-325925 A Japanese Patent Application Laid-Open No. 2001-325943

  However, even in the structure of the laminate outer package described in Patent Documents 7 to 11, since the folded paste margin portion becomes a dead space, there is room for further reduction of the dead space. Moreover, in the structure of the laminated exterior body described in the said patent documents 1-4 and 7-11, when the internal pressure inside an exterior body rises, the problem that a paste margin part will be gradually spread and peeling will arise easily. is there.

  The present invention has been made in view of the above-described problems of the prior art, and can reduce dead space and has a seal structure with excellent pressure resistance, for an electrochemical device for accommodating a plurality of power generation elements therein. An object of the present invention is to provide an exterior body and an electrochemical device using the exterior body.

  In order to achieve the above object, the present invention provides an exterior body for accommodating a plurality of power generation elements of an electrochemical device in a state where a partition wall is sandwiched between the power generation elements, and a pair of opposing power generation elements It has a seal part formed by laminating film and the partition wall, and the edges of the pair of laminate films are bonded to each other, and at least a part of the seal part is the exterior of the pair of laminate films. It is a built-in seal part accommodated inside the exterior body by being folded and bonded to the inside of the exterior body, and at least a part of the edge part folded to the interior side of the exterior body constitutes the partition wall An outer packaging for an electrochemical device is provided.

  According to such an exterior body for an electrochemical device, at least a part of the seal portion is a built-in seal portion of the above structure, so that the seal portion is compared with a conventional exterior body provided outside the exterior body. The dead space can be sufficiently reduced. In addition, the built-in seal portion having the above structure is less likely to peel off even when the internal pressure inside the exterior body increases, so that it does not work in the direction of expanding the seal portion, and can have excellent pressure resistance.

  Moreover, according to the said exterior body for electrochemical devices, the partition wall arrange | positioned between each electric power generation element is formed with the extended edge part of a laminate film, and a partition wall is separately prepared like the past and laminated film Compared with the case where it adhere | attaches, reduction of a dead space, thickness reduction, and the improvement of a pressure | voltage resistance are realizable.

  Furthermore, in the above-described conventional exterior body, the sealant tends to protrude from the end of the seal portion to the outside of the exterior body during hot pressing. Therefore, it is necessary to remove the protruding sealant, or if the sealant is not removed, the appearance deteriorates, the dead space increases due to the protruding sealant, or the process is caused by tearing or falling off of the protruding part. Problems such as defects are caused. On the other hand, according to the exterior body for an electrochemical device of the present invention, even if the sealant protrudes from the end of the seal portion during hot pressing, the sealant protrudes into the exterior body, so that the appearance deteriorates or the dead space There is no increase.

  The exterior body for an electrochemical device of the present invention preferably has a rectangular outer shape, and at least one of the two sides in contact with the side from which the electrode terminal is led out is the built-in seal portion. The exterior body having such a structure can more effectively obtain the effect of reducing dead space and improving pressure resistance by providing the built-in seal portion.

  The present invention also includes the outer package for an electrochemical device according to the present invention, a plurality of power generation elements and an electrolyte solution housed in a sealed state in the outer package, and one end connected to each electrode of the power generation element. An electrode terminal exposed at the other end of the exterior body, and the plurality of power generation elements are accommodated in the exterior body in a state of being connected in series with a partition wall interposed between the power generation elements. Provide an electrochemical device.

  Since such an electrochemical device includes the exterior body having the above-described structure, the dead space is sufficiently reduced and the pressure resistance is excellent, and a plurality of power generation elements connected in series are accommodated therein. Can increase the working voltage. Further, when a plurality of power generation elements are inserted into one exterior body, since the electrolyte solution between the power generation elements is made common, there is an advantage that it is easy to match the degree of deterioration of each power generation element.

  According to the present invention, a dead space can be sufficiently reduced, and an exterior body for an electrochemical device for accommodating a plurality of power generation elements having a seal structure excellent in pressure resistance, and electrochemical using the same A device can be provided.

It is a perspective view which shows suitable one Embodiment of the exterior body for electrochemical devices of this invention. It is a perspective view which shows other suitable one Embodiment of the exterior body for electrochemical devices of this invention. It is a perspective view which shows other suitable one Embodiment of the exterior body for electrochemical devices of this invention. It is a perspective view which shows other suitable one Embodiment of the exterior body for electrochemical devices of this invention. It is a perspective view which shows an example of the conventional exterior body for electrochemical devices. It is a schematic cross section which shows an example of the basic composition of the laminate film used as the constituent material of the exterior body for electrochemical devices of this invention. FIG. 2 is a series of process diagrams when the electrochemical device exterior body 1 shown in FIG. 1 is produced. FIG. 3 is a series of process diagrams when the electrochemical device exterior body 2 shown in FIG. 2 is manufactured. FIG. 4 is a series of process diagrams when producing the electrochemical device exterior body 3 shown in FIG. 3. FIG. 5 is a series of process diagrams when the electrochemical device exterior body 4 shown in FIG. 4 is produced. It is a front view which shows suitable one Embodiment of the electrochemical device (lithium ion secondary battery) of this invention. It is an expanded view which shows the inside of the lithium ion secondary battery shown in FIG. It is a schematic cross section at the time of cut | disconnecting the lithium ion secondary battery shown in FIG. 11 along the X1-X1 line | wire of FIG. It is a schematic cross section which shows the principal part at the time of cut | disconnecting the lithium ion secondary battery shown in FIG. 11 along the X2-X2 line | wire of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a perspective view showing a preferred embodiment of an exterior body for an electrochemical device according to the present invention. As shown in FIG. 1, the exterior body 1 of the present embodiment includes a pair of laminated films 51 and 52 (a first laminated film 51 and a second laminated film 52) facing each other, and the pair of laminated films 51. , 52 is bonded to the inside of the exterior body by bending the edges of the pair of laminate films 51, 52 to the inside of the exterior body and partially adhering them. The built-in seal portion 5 is provided. In the exterior body 1 of the present embodiment, both side edges of the second laminate film 52 are extended, and the partition walls 7 are formed by a pair of extended edges. The exterior body 1 can accommodate two power generation elements separated by a partition wall 7.

  The exterior body 1 has a rectangular outer shape, and is formed by bending a single laminate film. Further, in the exterior body 1, the side 1 </ b> A shown as the opening in FIG. 1 is a side leading to the electrode terminal, and the two sides 1 </ b> B and 1 </ b> C in contact with the side are both the built-in seal portion 5. . Further, the side 1D facing the side 1A of the exterior body 1 is a bent portion, and a pair of laminate films 51 and 52 are continuous. Therefore, the side 1D does not need a seal, and space saving is achieved.

  FIG. 2 is a perspective view showing another preferred embodiment of the exterior body for an electrochemical device of the present invention. As shown in FIG. 2, the exterior body 2 of the present embodiment includes a pair of laminated films 51 and 52 (a first laminated film 51 and a second laminated film 52) facing each other, and the pair of laminated films 51. , 52 is bonded to the inside of the exterior body by bending the edges of the pair of laminate films 51, 52 to the inside of the exterior body and partially adhering them. The built-in seal portion 5 is provided. In the exterior body 2 of the present embodiment, both side edges of the first laminate film 51 and the second laminate film 52 are extended, and two partition walls 7 are formed by the two pairs of extended edges. The exterior body 2 is capable of accommodating three power generation elements separated by a partition wall 7.

  The exterior body 2 has a rectangular outer shape, and is formed by bending a single rectangular laminate film. Further, in the exterior body 2, the side 2 </ b> A shown as the opening in FIG. 2 is a side from which the electrode terminal is derived, and the two sides 2 </ b> B and 2 </ b> C in contact with this are both the built-in seal portion 5. . The side 2D facing the side 2A of the exterior body 2 is a bent portion, and a pair of laminate films 51 and 52 are continuous. Therefore, the side 2D does not need a seal, and space saving is achieved.

  FIG. 3 is a perspective view showing another preferred embodiment of the exterior body for an electrochemical device of the present invention. As shown in FIG. 3, the exterior body 3 of the present embodiment includes a pair of laminated films 51 and 52 (a first laminated film 51 and a second laminated film 52) facing each other, and the pair of laminated films 51. , 52 is bonded to the inside of the exterior body by bending the edges of the pair of laminate films 51, 52 to the inside of the exterior body and partially adhering them. The built-in seal portion 5 is provided. In the exterior body 3 of the present embodiment, both side edges of the second laminate film 52 are extended to the same extent as the width of the exterior body 3, and each of the extended edges constitutes the partition wall 7 alone. Thus, two partition walls 7 are formed. As a result, the exterior body 3 can accommodate three power generation elements separated by the partition wall 7.

  The outer package 3 has a rectangular outer shape and is formed by bending a single laminate film. Further, in the exterior body 3, the side 3A shown as the opening in FIG. 3 is a side leading out the electrode terminal, and the two sides 3B and 3C in contact with the side 3A are both the built-in seal portion 5. . The side 3D facing the side 3A of the outer package 3 is a bent portion, and a pair of laminate films 51 and 52 are continuous. Therefore, the side 3D does not require a seal, and space saving is achieved.

  FIG. 4 is a perspective view showing another preferred embodiment of the exterior body for an electrochemical device of the present invention. As shown in FIG. 4, the exterior body 4 of the present embodiment includes a pair of laminated films 51 and 52 (a first laminated film 51 and a second laminated film 52) facing each other, and the pair of laminated films 51. , 52 is bonded to the inside of the exterior body by bending the edges of the pair of laminate films 51, 52 to the inside of the exterior body and partially adhering them. The built-in seal portion 5 is provided. In the exterior body 4 of the present embodiment, both side edges of the first laminate film 51 and the second laminate film 52 are extended to the same extent as the width of the exterior body 4, and each of the extended edges is independent. By forming the partition walls 7, four partition walls 7 are formed. Thereby, the exterior body 4 can accommodate five power generation elements separated by the partition wall 7.

  The exterior body 4 has a rectangular outer shape, and is formed by bending a single rectangular laminate film. Further, in the exterior body 4, the side 4 </ b> A shown as the opening in FIG. 4 is a side leading to the electrode terminal, and the two sides 4 </ b> B and 4 </ b> C in contact with the side 4 </ b> B are both the built-in seal portion 5. . Further, the side 4D facing the side 4A of the exterior body 4 is a bent portion, and a pair of laminate films 51 and 52 are continuous. Therefore, the side 4D does not require a seal, and space saving is achieved.

  On the other hand, FIG. 5 is a perspective view showing an example of a conventional exterior body in which a seal portion sealed across the partition wall 9 is formed outside the exterior body. As shown in FIG. 5, in the conventional exterior body 8, a seal portion 6 formed by bonding edges of a pair of laminate films 51 and 52 is provided outside the exterior body. In the exterior body 8, the side 8A shown as the opening in FIG. 5 is a side from which the electrode terminal is derived, and both the two sides 8B and 8C in contact with the side 8A and the side 8D facing the side 8A are sealed. It is part 6.

  In the structure of the exterior body 8 shown in FIG. 5, the seal part 6 becomes a dead space. Moreover, in the structure of the exterior body 8 shown in FIG. 5, since the partition 9 prepared separately from a pair of laminate films 51 and 52 is used, the thickness of the seal part 6 increases and the dead space is further increased. It becomes. On the other hand, according to the structure of the exterior bodies 1 to 4 shown in FIGS. 1 to 4, since the seal portion is the built-in seal portion 5, the dead space can be sufficiently reduced. Furthermore, by forming the partition wall 7 by the extended edge portion of the laminate film, the dead space can be sufficiently reduced without increasing the thickness of the built-in seal portion 5.

  Further, in the structure of the exterior body 8 shown in FIG. 5, when the internal pressure inside the exterior body increases, the force in the direction of the arrow P in FIG. Works and peels easily. On the other hand, according to the structure of the exterior bodies 1 to 4 shown in FIGS. 1 to 4, when the internal pressure inside the exterior body increases, the force does not work in the direction in which the built-in seal portion 5 is pushed and spread. It is difficult to occur and excellent pressure resistance is obtained.

  Furthermore, in the structure of the exterior body 5 shown in FIG. 5, the sealant tends to protrude from the end of the seal portion 6 toward the outside of the exterior body during hot pressing. On the other hand, according to the structure of the exterior bodies 1 to 4 shown in FIGS. 1 to 4, even if the sealant protrudes from the end of the built-in seal portion 5 during hot pressing, the sealant faces the inside of the exterior body. Since it protrudes, problems such as deterioration of the appearance, increase of the dead space, and process failure due to tearing or dropping of the protruding portion are suppressed, and the operation of removing the protruding sealant is not required.

  As the pair of laminate films 51 and 52 (the first laminate film 51 and the second laminate film 52) constituting the exterior bodies 1 to 4 of this embodiment, a laminate film having flexibility is used. Since the laminate film is lightweight and can be easily formed into a thin film, the electrochemical device itself can be formed into a thin film. Therefore, the original volume energy density can be easily improved, and the volume energy density based on the volume of the space in which the electrochemical device is to be installed can be easily improved.

  The laminate film is not particularly limited as long as it has flexibility, but it ensures the sufficient mechanical strength and light weight of the exterior body, while moisture and air enter the exterior body from the outside and the exterior. From the viewpoint of effectively preventing the diffusion of electrolyte components from the inside of the body to the outside, the polymer innermost layer that contacts the power generating element to be accommodated, and the side of the innermost layer that contacts the power generating element A laminate composed of three or more layers having at least a metal layer disposed on the opposite side of the metal layer and a polymer layer disposed on the opposite side of the metal layer in contact with the innermost layer. A film is preferred.

  As a laminated structure of the laminate film, for example, a laminate film having a configuration shown in FIG. A laminate film 53 shown in FIG. 6 has an innermost layer 53a made of a polymer that comes into contact with a power generation element housed inside the exterior body on the inner surface F1, and the other surface (outer surface) of the innermost layer 53a. It has a metal layer 53c disposed on top and a polymer outermost layer 53b disposed on the outer surface of the metal layer 53c.

  The innermost layer 53a is a flexible layer, and its constituent material can express the above-mentioned flexibility, and chemical stability with respect to the electrolyte solution accommodated in the exterior body. There is no particular limitation as long as it is a polymer having chemical stability against (chemical reaction, dissolution, and swelling) and oxygen and water (water in the air), but oxygen, water (air) A material having low permeability to the components of the water content and the electrolyte solution is preferable. Examples of the constituent material of the innermost layer 53a include engineering plastics and thermoplastic resins such as polyethylene, polypropylene, polyethylene acid modified products, polypropylene acid modified products, polyethylene ionomers, and polypropylene ionomers.

  The “engineering plastic” means a plastic having excellent mechanical properties, heat resistance, and durability used in mechanical parts, electrical parts, housing materials, etc., for example, polyacetal, polyamide, Examples include polycarbonate, polyoxytetramethyleneoxyterephthaloyl (polybutylene terephthalate), polyethylene terephthalate, polyimide, polyphenylene sulfide, and the like.

  Further, as the constituent material of the outermost layer 53b, the same constituent material as that of the innermost layer 53a may be used. In the exterior body of this embodiment, since the edge of the laminate film 53 is bent, the outer surfaces F2 of the laminate film 53 are bonded to each other in the built-in seal portion 5. Therefore, when the built-in seal portion 5 is formed by hot pressing, it is possible to selectively heat-seal the edge surfaces F2 by adjusting the heating temperature, so that the outermost layer 53b The constituent material is preferably a material having a lower melting point than that of the innermost layer 53a. Preferably, the constituent material of the outermost layer 53b includes polypropylene, polyethylene, nylon 6, nylon 11, nylon 12, polybutylene terephthalate (PBT), polyether ether ketone (PEEK), and the like. Among these, polypropylene and polyethylene are particularly preferable because of their extremely low water absorption.

  The metal layer 53c is preferably a layer formed of a metal material having corrosion resistance against oxygen, water (water in the air), and an electrolyte solution. For example, a metal foil made of aluminum, aluminum alloy, titanium, chromium, or the like may be used.

  As a laminate film used for the exterior body of the present embodiment, a laminate having a three-layer structure including an innermost layer 53a made of polyethylene terephthalate, a metal layer 53c made of aluminum, and an outermost layer 53b made of polypropylene. A film is particularly preferred.

  The laminate film 53 having the above-described structure can be produced by using a known production method such as a dry lamination method, a wet lamination method, a hot melt lamination method, or an extrusion lamination method. For example, a film to be a polymer layer constituting the laminate film 53 and a metal foil made of aluminum or the like are prepared. The metal foil can be prepared, for example, by rolling a metal material. Next, a laminate film (multilayer film) 53 is preferably formed by laminating a metal foil on the film to be a polymer layer via an adhesive so as to have a plurality of layers as described above. Is made. The obtained laminate film 53 is used after being cut into a predetermined shape and size.

  Next, the example of the manufacturing method of the exterior body for electrochemical devices mentioned above is demonstrated. FIGS. 7A to 7C are a series of process diagrams when the outer package 1 shown in FIG. 1 is manufactured. First, as shown in FIG. 7A, a single laminate film 50 is prepared. The laminate film 50 is bent at a fold line YY in the drawing. The laminate film 50 has regions of a first laminate film 51 and a second laminate film 52 that are arranged to face each other when folded at a folding line YY.

  51B and 52B in the figure are edges of the first laminate film 51 and the second laminate film 52, respectively, and this part is bent, and the overlapping edges of the first and second laminate films 51 and 52 are shown. The built-in seal portion 5 is formed by bonding them together. Moreover, the edge part of the 2nd laminate film 52 is extended rather than the edge part of the 1st laminate film 51, and the part which does not overlap with the edge part of the 1st laminate film 51 does not adhere | attach, but is a partition 7 is constituted. Moreover, 51A and 52A in a figure show the partial area | region which does not form the built-in seal part 5 of the 1st laminate film 51 and the 2nd laminate film 52, respectively.

  Next, as shown in FIG.7 (b), the edge parts 51B and 52B of the 1st and 2nd laminate films 51 and 52 are bend | folded to the side which accommodates the electric power generation element in the exterior body 1. FIG. Thereafter, as shown in FIG. 7 (c), the laminate film 50 is folded in two along the fold line YY, and the edge portion 51B and the edge portion of the edge portion 52B facing the edge portion 51B are bonded to each other, thereby incorporating the built-in seal portion. 5 is formed. Further, the partition wall 7 is formed by the extended region of the edge portion 52B which is not bonded. Thereby, the exterior body 1 can be produced. In the obtained exterior body 1, the power generation elements can be housed in the two housing portions separated by the partition wall 7.

  FIGS. 8A to 8C are a series of process diagrams when the outer package 2 shown in FIG. 2 is produced. First, as shown in FIG. 8A, a single rectangular laminate film 50 is prepared. The laminate film 50 is bent at a fold line YY in the drawing. The laminate film 50 has regions of a first laminate film 51 and a second laminate film 52 that are arranged to face each other when folded at a folding line YY.

  51B and 52B in the figure are the edge portions of the first laminate film 51 and the second laminate film 52, respectively, and this portion is bent so that the edges of the first and second laminate films 51 and 52 are connected to each other. The built-in seal portion 5 is formed by being partially bonded. In addition, the edge portions of the first and second laminate films 51 and 52 both have extended regions that are not bonded, and these regions constitute the partition wall 7. Moreover, 51A and 52A in a figure show the partial area | region which does not form the built-in seal part 5 of the 1st laminate film 51 and the 2nd laminate film 52, respectively.

  Next, as shown in FIG.8 (b), the edge parts 51B and 52B of the 1st and 2nd laminate films 51 and 52 are bend | folded to the side which accommodates the electric power generation element in the exterior body 2. FIG. Thereafter, as shown in FIG. 8 (c), the laminate film 50 is folded in two at the fold line YY, and the opposing edge portion 51B and edge portion 52B are partially bonded to form the built-in seal portion 5. To do. The range in which the edge portion 51B and the edge portion 52B are bonded is not particularly limited, but it is preferable that the seal structure having sufficient pressure resistance is obtained and that the housing of the plurality of power generating elements is not hindered. Then, two partition walls 7 are formed by the extended regions of the edge portions 51B and 52B that are not bonded. Thereby, the exterior body 2 can be produced. In the obtained exterior body 2, the power generation elements can be housed in the three housing portions separated by the partition walls 7.

  FIGS. 9A to 9C are a series of process diagrams when the outer package 3 shown in FIG. 3 is manufactured. First, as shown in FIG. 9A, a single laminate film 50 is prepared. The laminate film 50 is bent at a fold line YY in the drawing. The laminate film 50 has regions of a first laminate film 51 and a second laminate film 52 that are arranged to face each other when folded at a folding line YY.

  51B and 52B in the figure are edges of the first laminate film 51 and the second laminate film 52, respectively, and this part is bent, and the overlapping edges of the first and second laminate films 51 and 52 are shown. The built-in seal portion 5 is formed by bonding them together. Moreover, the edge part of the 2nd laminate film 52 is extended rather than the edge part of the 1st laminate film 51, and the part which does not overlap with the edge part of the 1st laminate film 51 does not adhere | attach, but is a partition 7 is constituted. Moreover, 51A and 52A in a figure show the partial area | region which does not form the built-in seal part 5 of the 1st laminate film 51 and the 2nd laminate film 52, respectively.

  Next, as shown in FIG. 9B, the edge portions 51 </ b> B and 52 </ b> B of the first and second laminate films 51 and 52 are bent to the side of the exterior body 3 that houses the power generation element. Thereafter, as shown in FIG. 9C, the laminate film 50 is folded in two at the fold line YY, and the edge 51B and the part of the edge 52B facing the edge 51B are bonded to each other, thereby incorporating the built-in seal part. 5 is formed. Moreover, the two partition walls 7 are formed by the extended region of the edge portion 52B that is not bonded. Thereby, the exterior body 3 can be produced. In the obtained exterior body 3, the power generation elements can be housed in the three housing portions separated by the partition walls 7.

  FIGS. 10A to 10C are a series of process diagrams when the outer package 4 shown in FIG. 4 is produced. First, as shown in FIG. 10A, a single laminate film 50 is prepared. The laminate film 50 is bent at a fold line YY in the drawing. The laminate film 50 has regions of a first laminate film 51 and a second laminate film 52 that are arranged to face each other when folded at a folding line YY. In addition, the laminate film 50 is provided with a cutting portion 55 for passing a lead connecting each power generating element.

  51B and 52B in the figure are the edge portions of the first laminate film 51 and the second laminate film 52, respectively, and this portion is bent so that the edges of the first and second laminate films 51 and 52 are connected to each other. The built-in seal portion 5 is formed by being partially bonded. In addition, the edge portions of the first and second laminate films 51 and 52 both have extended regions that are not bonded, and these regions constitute the partition wall 7. Moreover, 51A and 52A in a figure show the partial area | region which does not form the built-in seal part 5 of the 1st laminate film 51 and the 2nd laminate film 52, respectively.

  Next, as shown in FIG. 10 (b), the edge portions 51 </ b> B and 52 </ b> B of the first and second laminate films 51 and 52 are folded to the side of the exterior body 4 that houses the power generation element. Thereafter, as shown in FIG. 10 (c), the laminated film 50 is folded in two at the fold line YY, and the opposing edge portion 51B and edge portion 52B are partially bonded to form the built-in seal portion 5. To do. The range in which the edge portion 51B and the edge portion 52B are bonded is not particularly limited, but it is preferable that the seal structure having sufficient pressure resistance is obtained and that the housing of the plurality of power generating elements is not hindered. Then, the four partition walls 7 are formed by the extended regions of the edge portions 51B and 52B that are not bonded. Thereby, the exterior body 4 can be produced. In the obtained exterior body 4, the power generation elements can be housed in the five housing portions separated by the partition walls 7.

  In the method for manufacturing the exterior bodies 1 to 4, the bonding method between the facing edge portion 51 </ b> B and the edge portion 52 </ b> B is not particularly limited. For example, a bonding method using heat sealing or a bonding method using an adhesive can be used. . From the viewpoint of productivity, it is preferable to use a heat seal method. In the case of bonding by the heat sealing method, for example, a method of hot pressing by sandwiching only a portion where the opposing edge portions 51B and 52B are bonded with a thin blade can be used. Further, the laminate film 50 has a polymer innermost layer 53a, a metal layer 53c and a polymer outermost layer 53b as shown in FIG. 6, and the constituent material of the outermost layer 53b. If the melting point of the innermost layer 53a is lower than the melting point of the constituent material, a part of the exterior body (the part forming the built-in seal portion 5) is formed from the outside of the first and second laminate films 51 and 52. It is also possible to use a method in which heat pressing is performed to selectively heat-bond only between the facing edge portion 51B and the edge portion 52B.

  As mentioned above, although the suitable embodiment of the exterior body for electrochemical devices of this invention was described in detail, the exterior body for electrochemical devices of this invention is not limited to the said embodiment. For example, in the exterior bodies 1 to 4 in the description of the above embodiment, all the seal portions other than the side from which the electrode terminal is led out are the built-in seal portions 5, but some of the seal portions are the built-in seal portions 5. The other seal part may be the conventional seal part 6. Moreover, the exterior body of this invention is not limited to the rectangular thing shown in FIGS.

  Further, for example, in the exterior body 1 shown in FIG. 1, both side edges of the second laminate film 52 constituting the partition wall 7 are extended so as not to overlap each other but are spaced apart from each other. Is not particularly limited, and may be extended so that both side edges overlap each other. In addition, when providing a space | interval between the extended both-sides edge part, it is necessary to adjust a space | interval so that the contact between the two electric power generation elements arrange | positioned on both sides of the partition 7 may not arise. Such a change in structure is also possible for the exterior body 2 shown in FIG.

  Further, for example, in the exterior body 1 illustrated in FIG. 1, the shape of the extended edge portion may be changed so that the partition wall 7 is arranged at an interval from the side 1D. Similarly, the shape of the extended edge portion may be changed so that the partition wall 7 is spaced from the side 1A. In addition, when a space | interval is provided between the partition 7 and edge | side 1A and / or edge | side 1D, it is necessary to adjust a space | interval so that the contact between the two electric power generation elements arrange | positioned on both sides of the partition wall 7 may not arise. Such a change in structure is also possible for the exterior bodies 2 to 4 shown in FIGS.

  Furthermore, in the exterior bodies 1 to 4 shown in FIGS. 1 to 4, the first and second laminated films 51 and 52 are formed by bending a single laminated film. A film separate from the second laminate film 52 may be used. In this case, the bent portion of the exterior bodies 1 to 4 serves as a seal portion, but this seal portion can also be used as the built-in seal portion 5.

  Next, a preferred embodiment of an electrochemical device using the above-described electrochemical device exterior body will be described. In the present embodiment, a lithium ion secondary battery using the exterior body 1 shown in FIG. 1 as the exterior body will be described.

  FIG. 11 is a front view showing a preferred embodiment of the electrochemical device (lithium ion secondary battery) of the present invention. FIG. 12 is a development view showing the inside of the lithium ion secondary battery shown in FIG. Further, FIG. 13 is a schematic cross-sectional view of the lithium ion secondary battery shown in FIG. 11 cut along the line X1-X1 of FIG. 14 is a schematic cross-sectional view showing the main part when the lithium ion secondary battery shown in FIG. 11 is cut along the line X2-X2 of FIG.

  As shown in FIGS. 11 to 14, the lithium ion secondary battery 100 is mainly disposed adjacent to the plate-like negative electrode 10 and the plate-like positive electrode 20 facing each other, and between the negative electrode 10 and the positive electrode 20. The first and second power generation elements 61 and 62 configured by the plate-shaped separator 40, the lead 30 that connects the first power generation element 61 and the second power generation element 62 in series, and lithium ions The electrolyte solution containing, the exterior body 1 containing them in a sealed state, and one end of the first power generation element 61 is electrically connected to the negative electrode 10 and the other end is external to the exterior body 1. The negative electrode lead 12 protruding to the outside and the positive electrode lead 22 having one end electrically connected to the positive electrode 20 of the second power generation element 62 and the other end protruding to the outside of the exterior body 1. It consists of and. Hereinafter, details of each component of this embodiment will be described.

  In the present specification, the “negative electrode” is an electrode based on the polarity at the time of discharge of the battery and emits electrons by an oxidation reaction at the time of discharge. Further, the “positive electrode” is an electrode based on the polarity at the time of discharging of the battery and accepts electrons by a reduction reaction at the time of discharging.

  First, the negative electrode 10 and the positive electrode 20 will be described. The negative electrode 10 includes a negative electrode current collector and a negative electrode active material-containing layer formed on the negative electrode current collector. The positive electrode includes a positive electrode current collector and a positive electrode active material-containing layer formed on the positive electrode current collector.

  The negative electrode current collector and the positive electrode current collector are not particularly limited as long as they are good conductors that can sufficiently transfer charges to the negative electrode active material-containing layer and the positive electrode active material-containing layer, and are known lithium ion secondary batteries. The current collector used in the above can be used. For example, the negative electrode current collector and the positive electrode current collector include metal foils such as copper and aluminum, respectively.

  The negative electrode active material-containing layer of the negative electrode 10 is mainly composed of a negative electrode active material and a binder. Note that the negative electrode active material-containing layer preferably further contains a conductive additive.

The negative electrode active material is occlusion and release of lithium ions, desorption and insertion (intercalation) of lithium ions, or doping with lithium ions and counter anions of the lithium ions (for example, PF ₆ ⁻ , ClO ₄ ⁻ ). Any known negative electrode active material can be used without particular limitation as long as it can reversibly proceed with undoping. As such a negative electrode active material, for example, it can be combined with a carbon material such as natural graphite, artificial graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, or lithium such as Al, Si, or Sn. Examples thereof include amorphous compounds mainly composed of oxides such as metals, SiO, SiO ₂ , SiO _x , and SnO ₂ , lithium titanate (Li ₄ Ti ₅ O ₁₂ ), and TiO ₂ .

  As the binder used for the negative electrode 10, known binders can be used without particular limitation. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene. Copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer Examples thereof include fluororesins such as a polymer (ECTFE) and polyvinyl fluoride (PVF). This binder not only binds constituent materials such as active material particles and conductive assistants added as necessary, but also contributes to binding between the constituent materials and the current collector. Yes.

  In addition to the above, as the binder, for example, vinylidene fluoride-based fluororubber such as vinylidene fluoride-hexafluoropropylene-based fluororubber (VDF-HFP-based fluororubber) may be used.

  In addition to the above, as the binder, for example, polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, cellulose, styrene / butadiene rubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber and the like may be used. Also, thermoplastic elastomeric polymers such as styrene / butadiene / styrene block copolymers, hydrogenated products thereof, styrene / ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers, and hydrogenated products thereof. May be used. Further, syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymer, propylene / α-olefin (carbon number 2 to 12) copolymer and the like may be used. Further, a conductive polymer may be used.

  It does not specifically limit as a conductive support agent used as needed, A well-known conductive support agent can be used. Examples thereof include carbon blacks, carbon materials, metal powders such as copper, nickel, stainless steel, and iron, mixtures of carbon materials and metal powders, and conductive oxides such as ITO.

  The positive electrode active material-containing layer of the positive electrode 20 is mainly composed of a positive electrode active material and a binder. Note that the positive electrode active material-containing layer preferably further contains a conductive additive.

The positive electrode active material includes insertion and extraction of lithium ions, desorption and insertion of lithium ions (intercalation), or doping and dedoping of lithium ions and a counter anion (for example, ClO ₄ ⁻ ) of the lithium ions. If it can be made to advance reversibly, it will not specifically limit, A well-known electrode active material can be used. For example, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganese spinel (LiMn ₂ O ₄ ), and the general formula: LiNi _x Co _y Mn _z M _a O ₂ (x + y + z + a = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, 0 ≦ a ≦ 1, and M is one or more elements selected from Al, Mg, Nb, Ti, Cu, Zn, and Cr) Complex metal oxide, lithium vanadium compound (LiV ₂ O ₅ ), olivine type LiMPO ₄ (where M is one or more elements selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr) Or a composite metal oxide such as lithium titanate (Li ₄ Ti ₅ O ₁₂ ).

  As the binder used for the positive electrode 20, the same binder as that used for the negative electrode 10 can be used. Moreover, as a conductive support agent used for the positive electrode 20 as needed, the same conductive support agent used for the negative electrode 10 can be used.

  The positive electrode current collector of the positive electrode 20 is electrically connected to one end of a positive electrode lead 22 made of, for example, aluminum, and the other end of the positive electrode lead 22 extends to the outside of the exterior body 1. On the other hand, the negative electrode current collector of the negative electrode 10 is also electrically connected to one end of a negative electrode lead 12 made of, for example, copper or nickel, and the other end of the negative electrode lead 12 extends to the outside of the exterior body 1.

  The separator 40 disposed between the negative electrode 10 and the positive electrode 20 is not particularly limited as long as it is formed of a porous body having ion permeability and electronic insulation properties, and is a known lithium ion secondary. The separator used for a battery can be used. For example, a laminate of a film made of polyethylene, polypropylene or polyolefin, a stretched film of a mixture of the above polymers, or a fiber nonwoven fabric made of at least one constituent material selected from the group consisting of cellulose, polyester and polypropylene, etc. It is done.

An electrolyte solution (not shown) is filled in the internal space of the outer package 1, and a part of the electrolyte solution is contained in the negative electrode 10, the positive electrode 20, and the separator 40. As the electrolyte solution, a non-aqueous electrolyte solution in which a lithium salt is dissolved in an organic solvent is used. Examples of the lithium salt include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CF ₂ SO ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN Salts such as (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiN (CF ₃ CF ₂ CO) ₂ are used. In addition, these salts may be used individually by 1 type, and may use 2 or more types together. Further, the electrolyte solution may be gelled by adding a polymer or the like.

  Moreover, the solvent currently used for the well-known electrochemical device can be used for an organic solvent. For example, propylene carbonate, ethylene carbonate, diethyl carbonate and the like are preferable. These may be used alone or in combination of two or more at any ratio.

  The exterior body 1 has the structure shown in FIGS. 1 and 7, and the seal part other than the side from which the electrode terminal is led out is a built-in seal part 5. Further, as shown in FIGS. 11 and 12, the edge portions 51a and 52a of the first laminate film 51 and the second laminate film 52 where the built-in seal portion 5 is not formed are electrode terminals (the negative lead 12 and the positive lead). Sealed with the lead 22) in between. The negative electrode lead 12 and the first and second laminated films are in the portion of the negative electrode lead 12 that contacts the edge portion 51a of the first laminate film 51 and the seal portion of the edge portion 52a of the second laminate film 52. An insulator 14 for preventing contact with the metal layer is coated. Further, the positive electrode lead 22 and the first and second laminates are formed on the positive electrode lead 22 portion that contacts the seal portion of the edge portion 51 a of the first laminate film 51 and the edge portion 52 a of the second laminate film 52. An insulator 24 for preventing contact with the metal layer in the film is coated.

  The configurations of the insulator 14 and the insulator 24 are not particularly limited, but may be formed of, for example, a polymer. Note that the insulator 14 and the insulator 24 may not be disposed as long as the metal layer in the laminate film can be sufficiently prevented from contacting each of the negative electrode lead 12 and the positive electrode lead 22.

  Inside the exterior body 1, two power generation elements (a first power generation element 61 and a second power generation element 62) are accommodated with the partition wall 7 interposed therebetween. These first and second power generating elements 61 and 62 are separated by a partition wall 7 so as not to be in direct contact with each other, and are connected in series via a lead 30 inside the exterior body 1 as shown in FIG. . The lead 30 is passed through a gap between the partition wall 7 and the bent portion of the laminate film 50.

  Next, a method for manufacturing the above-described lithium ion secondary battery 100 will be described.

  The manufacturing method of the first and second power generation elements 61 and 62 (a laminated body in which the negative electrode 10, the separator 40, and the positive electrode 20 are sequentially laminated in this order) is not particularly limited, and is a known lithium ion secondary battery. A publicly known method adopted for production can be used.

  When the negative electrode 10 and the positive electrode 20 are produced, first, the above-described constituent components are mixed and dispersed in a solvent in which the binder can be dissolved to produce an electrode-forming coating solution (slurry or paste). The solvent is not particularly limited as long as the binder can be dissolved. For example, N-methyl-2-pyrrolidone, N, N-dimethylformamide and the like can be used.

  Next, the electrode forming coating solution is applied onto the surface of the current collector, dried, and rolled to form an active material-containing layer on the current collector, thereby completing the production of the negative electrode 10 and the positive electrode 20. Here, the method for applying the electrode-forming coating solution to the surface of the current collector is not particularly limited, and may be appropriately determined according to the material, shape, and the like of the current collector. Examples of the coating method include a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, a doctor blade method, a gravure coating method, and a screen printing method.

  Thereafter, the negative electrode lead 12 is electrically connected to the negative electrode 10 of the first power generation element 61, and the negative electrode lead 12 is electrically connected to the positive electrode 20 of the second power generation element 62.

  Next, the separator 40 is disposed between the negative electrode 10 and the positive electrode 20 in a contacted state (preferably in a non-adhered state), and the first and second power generation elements 61 and 62 are completed. At this time, it arrange | positions so that the surface by the side of the negative electrode active material content layer of the negative electrode 10 and the surface by the side of the positive electrode active material content layer of the positive electrode 20 may contact with the separator 40.

  Thereafter, the positive electrode 20 of the first power generation element 61 and the negative electrode 10 of the second power generation element 62 are electrically connected by the lead 30. The material of the lead 30 is not particularly limited as long as it has conductivity. For example, the same material as the current collector of each electrode, the negative electrode lead 12 and the positive electrode lead 22 is used. Further, the lead 30 may be configured by extending a part of either the positive electrode current collector of the first power generation element 61 or the negative electrode current collector of the second power generation element 62. .

  On the other hand, the exterior body 1 is manufactured by the manufacturing method described above. As shown in FIGS. 1 and 7, the exterior body 1 is partially heated to secure an opening for introducing the first and second power generation elements 61 and 62 into the exterior body 1. The part which does not seal is provided. Thereby, the exterior body 1 in a state having an opening is obtained.

  Then, the first and second power generation elements 61 and 62 to which the negative electrode lead 12 and the positive electrode lead 22 are electrically connected are inserted into the exterior body 1 having an opening. Then, an electrolyte solution is injected. Subsequently, in a state where a part of the negative electrode lead 12 and the positive electrode lead 22 are respectively inserted into the outer package 1, the opening of the outer package 1 is sealed using a sealing machine. Thereby, the production of the outer package 1 and the lithium ion secondary battery 100 is completed.

  As mentioned above, although the suitable embodiment of the electrochemical device of this invention was described in detail, this invention is not limited to the said embodiment. For example, in the description of the above embodiment, the lithium ion secondary battery 100 including one negative electrode 10 and one positive electrode 20 has been described. However, the negative electrode 10 and the positive electrode 20 are each provided with two or more negative electrodes 10 and 20 positive electrodes. One separator 40 may be always arranged between the two.

  Moreover, in the said embodiment, when producing the electrochemical device 100, the case where the 1st and 2nd electric power generation elements 61 and 62 were inserted after producing the exterior body 1 previously was demonstrated. Before folding the edges of the laminate films 51 and 52, the first and second power generating elements 61 and 62 are arranged in the state shown in FIG. 12, and then the exterior body 1 is attached according to the procedure shown in FIG. The electrochemical device 100 may be formed by injecting an electrolyte solution and sealing the opening. This is because the first and second power generating elements 61 and 62 are connected by the lead 30, and therefore, when inserting the first and second power generating elements 61 and 62 into the pre-made exterior body 1, the insertion work is difficult due to the presence of the partition wall 7. This is because there may be cases. In particular, when the number of power generation elements is large, it is preferable to arrange a plurality of power generation elements and to produce the exterior body in parallel, which can improve work efficiency. In addition, when the power generation elements are connected to each other with the leads 30 inside the exterior body, if the partition wall 7 is obstructed, a cutting portion for passing the leads 30 (for example, a cutting portion 55 as shown in FIG. 10). It is preferable to form a hole in the partition wall 7.

  Furthermore, in the said embodiment, although the structure which connects each electric power generation element with the lead | read | reed 30 inside the exterior body was shown, a lead | read | reed may be taken out of the exterior body and each power generation element may be connected. In this case, it is not necessary to form a cut portion or hole for passing the lead 30 as described above in the partition wall 7. In addition, when a lead is connected outside the exterior body, a balance circuit or a protection circuit can be connected to the lead. In particular, when the number of power generation elements is three or more, it is preferable to connect the balance circuit by extending the leads to the outside of the exterior body.

  Moreover, as the electrochemical device 100 of the said embodiment, although the structure which has the lead | read | reed 12 for negative electrodes and the lead | read | reed 22 for positive electrodes one each was shown, in order to take out a lead outside the exterior body and to connect each electric power generation element For example, it is good also as a structure which provides the lead | read | reed 12 for negative electrodes and the lead | read | reed 22 for positive electrodes for every electric power generation element, and connects in series outside the exterior body 1. FIG.

  In addition, the structure of the exterior body in which the edge of the laminate film is extended to form a partition is effective in reducing dead space, reducing thickness, and improving pressure resistance, even if the built-in seal is not formed. Structure. Further, the exterior body may have a structure in which each accommodating portion is completely partitioned by the partition wall 7 so that the electrolyte solution cannot pass between the accommodating portions that accommodate the respective power generation elements.

  In the description of the above embodiment, the case where the exterior body 1 shown in FIG. 1 is used as the exterior body has been described. However, the exterior bodies 2 to 4 shown in FIGS. You may use the exterior body of another structure which has the part 5 and the partition 7 comprised by the extended edge part. Furthermore, the electrochemical device (lithium ion secondary battery) of the present invention is not limited to the shape shown in FIG.

  Moreover, the number of the electric power generation elements accommodated in the exterior body is 2 or more, and it is preferable that it is 2-5. In addition to the partition wall 7 constituted by the extended edge of the laminate film, a separately prepared partition wall as shown in FIG. 5 may be added to increase the number of power generating elements accommodated in the exterior body. .

  In the description of the above embodiment, the case where the electrochemical device is a lithium ion secondary battery has been described. However, the electrochemical device of the present invention is not limited to a lithium ion secondary battery, and a metallic lithium secondary battery. Secondary batteries other than lithium ion secondary batteries such as batteries, and electrochemical capacitors such as electric double layer capacitors, pseudo-capacitance capacitors, pseudo capacitors, and redox capacitors may be used. In the case of an electrochemical device other than a lithium ion secondary battery, a material suitable for each electrochemical device may be used as the electrode active material. For example, in the case of an electric double layer capacitor, acetylene black, graphite, graphite, activated carbon, or the like is used as an active material contained in the positive electrode active material-containing layer and the negative electrode active material-containing layer.

DESCRIPTION OF SYMBOLS 1, 2, 3, 4 ... Electrochemical device exterior body, 5 ... Built-in seal part, 7 ... Partition, 10 ... Negative electrode, 12 ... Negative electrode lead, 14 ... Insulator, 20 ... Positive electrode, 22 ... Positive electrode lead, 24 ... Insulator, 30 ... Lead, 40 ... Separator, 50 ... Laminate film, 51 ... First laminate film, 52 ... Second laminate film, 61 ... First power generation element, 62 ... Second power generation element, 100: Lithium ion secondary battery.

Claims (3)

An exterior body for accommodating a plurality of power generation elements of an electrochemical device in a state where a partition wall is sandwiched between the power generation elements,
It is composed of a pair of laminated films facing each other and the partition wall,
Having a seal part formed by bonding edges of the pair of laminate films;
At least a part of the seal part is a built-in seal part housed inside the exterior body by bending and bonding the edges of the pair of laminate films to the inside of the exterior body,
An exterior body for an electrochemical device, wherein at least a part of the edge bent to the inner side of the exterior body is extended so as to constitute the partition wall. The outer shape is rectangular,
The exterior body for an electrochemical device according to claim 1, wherein at least one of two sides in contact with a side from which the electrode terminal is led out serves as the built-in seal portion. The exterior body for an electrochemical device according to claim 1 or 2,
A plurality of power generation elements and electrolyte solution housed in a sealed state in the exterior body;
One end is connected to each electrode of the power generation element, and the other end is exposed to the outside of the exterior body,
And a plurality of the power generation elements are housed in the exterior body in a state where the power generation elements are connected in series with a partition wall interposed between the power generation elements.

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