JP2007087922A - Film package energy storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film package energy storage device which ensures an accurate operation of a safety valve by eliminating an adverse effect by creep for a long period of time. <P>SOLUTION: The film package energy storage device 1 includes a joining valve part 18 which is formed on a part of a sealed outer edge 14 a film package 10, and conducts an inside and outside of the package 10 by opening at least partly when inner pressure of an electrode body unit storing space is raised to a predetermined level. The joining valve part 18 includes a main joining part 15 having joining intensity corresponding to a predetermined pressure and a sub-joining part 16 having a lower joining intensity than the main joining part 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a power storage device. In particular, the present invention relates to a film package power storage device provided with a joint valve portion that functions as a safety valve .

In a so-called film package power storage device having a structure in which an electrode body unit is housed and sealed in a film package formed by bonding exterior films such as laminate films by heat welding or the like, a part of the outer edge of the film package It is known to provide a portion having a low film bonding strength so that the portion functions as a safety valve . That is, when the internal pressure of the film package rises to a predetermined pressure, an internal pressure release path is formed by preferentially opening the low bonding strength portion so as to allow ventilation.

Such safety valve is a power storage device provided, for example, Patent Document 1, the time of sealing the full Irumu together that make up the outer edge of the film package is thermally welded, the ambient heat welding temperature of the portion In addition, a power storage device is described in which the welding strength (bonding strength) of the portion is made lower than that of the surroundings by carrying out at a low temperature. Thereby, when the internal pressure of the electrode body accommodation space of a film package rises more than predetermined pressure, this low junction strength part functions as a safety valve, and it can open | release, and an internal pressure can be open | released.
As another prior art document relates to a power storage device having a safety valve which is formed by welding between such off Irumu include Patent Document 2-6. Patent documents 7 and 8 are mentioned as other prior art documents about a battery or an electrochemical element.

Japanese Patent Laid-Open No. 11-86823 JP 2001-266814 A JP 2001-93489 A Japanese Patent Laid-Open No. 10-55792 JP 2002-151020 A JP 2002-056835 A JP 10-144279 A JP 2004-103258 A

Incidentally, in this type of film package power storage device, safe even during normal use of pressure above a predetermined pressure all the valve UNA by Ru is opened does not rise, over time somewhat in the internal pressure in the film splicing part constituting a safety valve ( Stress). When such stress is applied continuously or intermittently over a long period of time, a so-called creep (strain gradually increases due to the stress and decreases the bonding strength between the films) in the film bonding portion constituting the safety valve. The same shall apply hereinafter). In particular, when the environmental temperature is relatively high, or when the charge / discharge frequency is high, the above-mentioned creep is likely to occur. If the joint strength is excessively reduced by such creep, there is a possibility that the safety valve may be opened when an internal pressure lower than a predetermined pressure initially set as the pressure at which the safety valve opens is not preferable.

Further, in a film package power storage device including a safety valve of a type that operates by opening a part of the sealed outer edge of the film package, it is beneficial if the safety valve can be operated more appropriately.

The present invention, which has been created to solve the problems associated film package power storage device having such a conventional safety valve, of the type portion of the sealed outer edges of the film package is operated open Provided is a film package power storage device including a safety valve , which eliminates the influence of internal pressure (stress) during normal use, prevents creep from progressing, and ensures the correct operation of the safety valve over a long period of time For the purpose.

Further, the present invention provides a film package power storage device with a type of safety valve portion of the sealed outer edges of the film package is operated open, Ahn Zenben better (e.g., inside and outside of the film package It is an object of the present invention to provide a power storage device that can be operated more accurately (in at least one of the following points: the position at which the battery is communicated, the opening range, and the internal pressure leading to the opening).

The present invention relates to a power storage device in which an electrode unit is accommodated inside a film package .
The film package has a joint valve portion formed in a part of the periphery of the electrode body unit . The joint valve portion is formed by overlapping films, and has a main joint portion having high joint strength between films and a sub-joint portion having low joint strength between films. The sub-joining part is formed inside the main joining part.
In this specification, the “power storage device” refers to a device including one or more power storage elements (typically batteries or capacitors) that can extract predetermined electrical energy, and is not limited to a specific power storage mechanism. A battery such as a lithium primary battery or other primary battery, a nickel-hydrogen secondary battery, a lithium secondary battery or other secondary battery, or a capacitor (physical battery) such as an electric double layer capacitor is included in the power storage device referred to herein. This is a typical example.
In the present specification, the “electrode unit” refers to a structure that includes at least one positive electrode and one negative electrode and serves as a main body of a battery or a capacitor (an electricity storage element).

The power storage device of the above construction, during normal use, the internal pressure of the accommodation space of the electrode body unit is applied to the sub-junction, so that the said pressure to the main junction constituting a main body of the valve that communicates the inside and outside of the film package it is possible to prevent that you directly transmitted. For this reason, the occurrence of creep as described above is suppressed at the main joint, and a predetermined joint strength can be maintained over a long period of time.
Therefore, according to the power storage device provided with the joint valve portion (safety valve) having such a configuration, a desired function preset in the safety valve with respect to the internal pressure of the film package (that is, the predetermined pressure in which the internal pressure of the electrode body housing space is set in advance) It can be ensured over a long period of time that the main joint of the joint valve part does not open until the pressure is reached.

It is other single film package power storage device of the present invention relates to a power storage device that houses the electrode body unit inside the film package.
The film package has a joint valve portion formed in a part of the periphery of the electrode body unit . The joint valve portion is formed by overlapping films, and a sub-joint portion, a non-joint region, and a main joint portion are formed in order from the inside to the outside of the film package. The joint strength of the main joint is equal to or greater than the joint strength of the sub-joint.

In the power storage device having the above configuration , the non-joining portion is formed between the sub-joining portion and the main joining portion of the joining valve portion, so that the main joining portion and the sub-joining portion are physically and functionally separated. Is done. Thereby, the pressure transmission to the main joint during normal use is blocked by the sub-joint, and creep generation at the main joint can be effectively prevented over a long period of time.
Therefore, according to the charge reservoir with such a configuration, the withstand voltage performance of the film package charge reservoir is maintained in a good good.

Surrounding film package, the flange portion being bonded overlap between the films and is formed, joint valve portion is preferably formed in a part of the flange portion.
In this case, the joining strength of the joining valve portion is lower than the joining strength of the flange portion .
The charge reservoir with such a configuration, the junction valve unit abovementioned effect is achieved with a simple configuration. Moreover, a complicated operation is not required for forming the joint valve portion , and an increase in manufacturing cost can be suppressed.

The power storage device of one embodiment of the present invention includes a frame body that holds the outer edge of the film package . In this case, the junction valve unit is preferably exposed to the outside without being blocked by the frame.
In the power storage device having the above configuration, the film package is mechanically protected . Further, by providing the above-mentioned frame, at the normal time and the internal pressure abnormally increased use, the internal pressure of the package of the electrode body unit housing space, concentrated on the junction valve unit. Therefore, according to the power storage device having such a configuration, it is possible to suppress the occurrence of the creep in a portion other than the joint valve portion (particularly the sub joint portion) of the outer edge (for example, the flange portion).

The power storage device of one embodiment of the present invention also includes a frame body that holds the outer edge of the film package . In this aspect, a notch portion that forms a gap between the joint valve portion and the frame body while shielding the joint valve portion at a portion facing the joint valve portion of the frame body from the inner peripheral end of the frame body. It is formed continuously to the outer peripheral end.
In the power storage device of the above configuration,該接joint portion by the joint valve portion is shielded Ru are mechanically protected. Further, the internal pressure of the package of the electrode body unit housing space is concentrated in the junction valve unit. Therefore, according to the power storage device having such a configuration, it is possible to suppress the occurrence of the creep in a portion other than the outer joint valve portion.

Another one of the power storage device provided by the present invention relates to a power storage device outer edge houses the inside electrode body unit of the film packages are held by the frame member.
The film package has a joint valve portion formed in a part of the periphery of the electrode body unit . The joint valve portion is formed by overlapping films. The joint valve unit that faces portions of the frame, notches which form a gap between the joint valve unit and the frame while shielding the joint valve portion is formed. The notch is formed continuously from the inner peripheral end to the outer peripheral end of the frame.
The power storage device of the above configuration, the notch portion provided in opposite parts with joint valve portion selectively gap between the part and the frame constituting the joining valve portion of the outer edge of the film package Is formed. Thus, the internal pressure of the electrode body unit accommodation section can be concentrated (selectively) applied to the joint valve portion. Therefore, when the internal pressure abnormality increases, the bonded portion of the joint valve portion is preferentially opened, and the joint valve portion can appropriately function as a safety valve. The joining valve portion by being shielded by the frame body, it is possible to mechanically protect the joint valve unit. Moreover, by having the said frame, it can suppress that the said creep arises in parts other than the joining valve part of an outer edge at the time of normal use and internal pressure abnormal increase.

The electric storage device with the above frame, than the opening area of the inner peripheral edge side of the frame of the gap formed between the contact joint section notch, the outer peripheral edge side of the frame of the gap towards the opening area is small, and it is preferably formed so as not corners that protrude at right angles or less angle to the inner surface of the cutout portion facing the contact joint section.
When the bonding portion of the joint valve portion is opened due to an increase in internal pressure, the opening of the bonding portion typically proceeds from the inside (side closer to the electrode body unit) to the outside. Therefore, by forming the cutout portion of the frame body in the shape described above, the opening due to the increase in internal pressure can be smoothly advanced from the inside to the outside. Further, it is possible to prevent the film package (particularly the joint valve portion) swelled by the internal pressure from being excessively pressed against the frame body and being damaged. As a result, according to the power storage device having such a configuration, the joint valve portion can be more appropriately operated as a safety valve.

In the above frame body with a power storage device, it is preferable the inner surface of the opposite notch and abutting joint portion is a gently curved surface.
According to the above power storage device can Rukoto allowed to proceed more smoothly to the outer peripheral side of the opening of the adhered portion from the inner circumferential side. Moreover, damage to the film package can be prevented at a higher level. Usually, a better effect is realized by forming the inner surface shape of the notch portion into a gently curved surface shape (that is, a concave surface shape) mainly bulging toward the open side of the bonded portion.

Contact joint portion, and the welding portion being welded overlap is between the films, the other end one end with are previously formed between the superimposed film in contact with the welded portion is opened at the outer end of the film package it is also preferred to include an opening through path.
In the power storage device having such a configuration, when the welded portion is any portion of the open portion is opened to reach the passage opening, the opening portion and the inner and outer (electrode body unit housing space of the film package through the opening passage, and the outside of the film package ) Communicate. Therefore, even if the position at which the opening of the weld progresses (position at which the open portion is formed) and the shape (width, etc.) of the open portion vary somewhat, the position of the outlet of the communication path that communicates the inside and outside of the film package , It can be defined by the outlet (the other end described above) of a previously formed opening passage. Also, inside and outside of the film package is opened internal pressure when communicating, since the progress of thereafter opening of the welded portion is prevented, the opening area of the outlet of the communication passage becomes excessively large can be prevented. Typically, the size of the outlet of the communication passage can be defined by the size of the outlet of the previously formed opening passage. Such embodiments, for example, it is advantageous if it is intended to introduce the gas discharged from the internal pressure release at accommodating portion to a predetermined exhaust passage.

  Another power storage device according to the present invention relates to a power storage device that includes a frame that sandwiches an outer edge where films are overlapped with each other, and that houses an electrode unit inside a film package. A thin portion that is recessed toward a surface sandwiching the outer edge is formed in a part of the frame. The thin portion is continuous from the inner peripheral end to the outer peripheral end of the frame.

  In the power storage device in which the electrode body unit is accommodated inside the film package, pressure fluctuation occurs in the electrode body unit accommodation section during normal use, and the influence is likely to appear in the flange portion. If the flange portion is constrained by the frame body, the adhesive strength between the films of the flange portion can be maintained at a desired strength for a long time even if the pressure in the electrode body unit accommodation section is repeatedly changed. By having the frame, it is possible to suppress the occurrence of creep in the flange portion during normal use.
  When a thin portion is formed in a part of the frame, the restraining force is lower in the thin portion than in other parts of the frame. Therefore, when the internal pressure in the accommodating portion rises abnormally, the flange portion facing the thin portion is opened. The flange part restrained with a thin part can be functioned as a safety valve (joining valve part). It is possible to prevent the pressure in the housing portion from rising excessively. In addition, the joint strength of the flange part which opposes the thin part of a frame should just be equal to or less than a remainder.

  The thin-walled portion is preferably an arch-shaped depression that curves toward the surface sandwiching the outer edge.
  According to said structure, thickness distributes within the thin area | region with a weak restraining force. The central part of the thin part is the thinnest, and the binding force of the film package is also the weakest. When the internal pressure of the electrode unit housing space rises abnormally, the flange portion is first opened at the central portion of the thin portion, and thereafter proceeds outward. Therefore, the flange portion can be smoothly opened by forming the thin portion of the frame in the above shape.
  As a result, according to the power storage device having such a configuration, the joint valve portion can be more appropriately operated as a safety valve.

  Another aspect of the present invention relates to a frame for holding a film package power storage device having a flange portion around which films overlap each other.
  A groove for sandwiching the flange is formed on the inner peripheral side of the frame and the like, and at least a part of the groove is closed on the outer peripheral side.

  If the groove is formed on the inner peripheral side of the frame or the like, the flange of the film package can be accommodated in the groove. The flange portion is pressed by the inner wall surface. Further, the groove portion of the frame body is closed at at least a part of the outer peripheral end of the frame body. By enlarging the groove on the outer peripheral surface of the frame, expansion of the groove width is suppressed. Therefore, it is difficult for the restraining force that the wall surface of the groove inner wall acts on the flange portion to decrease. When the film package power storage device is held using the frame body of this configuration, creep of the flange portion is suppressed. In addition, the groove | channel may be closed over the perimeter of an outer peripheral end, and may be closed intermittently. What is necessary is just to close so that the breadth of a groove width can be suppressed. For example, even if only the corner groove where the influence of the internal pressure tends to concentrate is closed, the effect of the present frame can be sufficiently obtained.

  A plurality of frame members can be joined to form a frame. When the outline of the flange part of the film package power storage device has a corner part and a straight part, it is preferable that the joint part joining the individual frame members is joined at the straight part.

  When a frame is formed by combining a plurality of frame members, it is easy to mount the frame on the film package power storage device. Further, the influence of the internal pressure fluctuation of the electrode body housing space is most easily concentrated at the corner portion of the power storage device. The corner flange portion is prone to creep due to internal pressure fluctuations. On the other hand, the side part is less affected by the internal pressure fluctuation than the corner part. If there is no joint part that joins the frame members to the corner part that is susceptible to pressure fluctuations, the restraining force that the frame body applies to the flange part of the corner part becomes uniform. According to this configuration, mounting to the power storage device is easy, and creep of the flange portion is suppressed.

  It is preferable that the plurality of frame members are mechanically joined by the engaging member.

  When members are joined together by the engaging member, the time required for joining is short. When the frame body of this configuration is used, the time required to assemble the frame body can be saved. In addition to facilitating the joining of the frame members, the force applied to the joining of the frame members can be made uniform.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and the drawings and common general technical knowledge in the field.

One film package power storage device ( film exterior power storage device ) provided by the present invention is provided with a joint valve portion having a configuration disclosed herein on a part of a sealed outer edge of a film package ( film exterior body ) . The type and shape of the power storage element included in the manufacturing process and the power storage device are not particularly limited.
Typical examples to which the present invention is applied include various film package batteries (primary batteries, secondary batteries). The electrode body unit and other power storage elements (for example, cells constituting the secondary battery) housed in the power storage device are not limited to one, but two or more electrode body units are housed in one film package (typical May be an assembled battery).
The electrode body unit mounted on the film package battery or other power storage device disclosed herein is particularly capable of being a power storage element component (or a power generation element component) capable of storing and discharging predetermined power. It is not limited. Typical power storage elements include various types of primary batteries (eg, lithium primary batteries, manganese batteries), secondary batteries (eg, lithium secondary batteries, nickel metal hydride batteries), or capacitors (eg, electric double layer capacitors). be able to. For example, an electrode body unit formed by winding a sheet-shaped positive electrode and negative electrode together with a separator or an electrode body unit formed by laminating a plurality of sheet-shaped positive electrodes, negative electrodes, and separators, as used in lithium secondary batteries, It is a typical example of the electrode body unit which comprises the film package electrical storage apparatus (film package battery) disclosed here. There is no restriction | limiting in particular in the shape and size of the electrode body unit of a film package electrical storage apparatus, A desired form and size can be taken.

The exterior film (that is, the exterior film) constituting the film package itself of the film package power storage device of the present invention is particularly limited as long as it constitutes a package of this type of film package power storage device (for example, a secondary battery). Can be used without any problem. For example, a laminate film conventionally used as a package for a lithium secondary battery or the like can be used.
Preferably, it is composed of an outer surface (protective) layer composed of a high melting point resin (for example, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyamide (PA) resin) and a metal foil (for example, aluminum, steel). A barrier layer (a barrier layer that blocks gas and moisture), and an adhesive layer composed of a heat-welding resin (a resin having a relatively low melting point, for example, an olefin resin such as ethylene vinyl acetate, polyethylene, or polypropylene) A laminate film having a three-layer structure can be suitably used. Such a three-layer laminate film can be easily bonded (welded) to each other by using an appropriate thermocompression bonding means (for example, a heat press machine).

Next, the safety valve ( internal pressure release mechanism or joint valve portion) according to the present invention will be described.
The safety valve disclosed here has a joint valve part formed by adhesion of the films overlapped with each other. Further, the joint valve portion has a main joint portion for releasing the internal pressure by communicating the inside and outside of the package , that is, the housing portion and the external atmosphere when the pressure in the housing portion of the film package becomes equal to or higher than a predetermined pressure. Further, in order to prevent stress that causes generation and progress of creep from being applied to the main joint during normal use of the power storage device over time, the position is closer to the housing portion than the main joint. During normal use, it has at least one sub-joint formed at a position where the internal pressure of the storage portion (hereinafter simply referred to as internal pressure means the pressure of the storage portion) is easily applied.
These joining portions are joined with a joining strength (peeling strength) weaker than a sealing portion at the outer edge of the film package (that is, an adhesion (welding) portion between exterior films for sealing the inside of the housing portion). . The main joint is opened when the internal pressure rises to a predetermined set pressure (in other words, the adhesion between the films is maintained until the predetermined pressure is reached). It is joined to have performance. On the other hand, the sub-joint portion is provided so as to absorb, instead of the main joint portion, the stress accompanying the change in internal pressure that occurs during normal use of the power storage device.

The main joint portion and the sub joint portion in the joint valve portion may be formed adjacent to each other, or may be formed apart from each other. When formed adjacent to each other, although not particularly limited, for example, the main joint portion is formed so as to have a pressure resistance value of about 50 to 70% of the pressure resistance value (bonding strength) of the sealing portion of the outer edge of the film package , Furthermore, it is preferable to form the sub-joint portion so that the withstand voltage value is about 40 to 60% of the main joint portion. Particularly when applied but not limited to, the present invention into a film package battery such as a lithium secondary battery, when the withstand voltage value of the conventional film sealing portion is 1MPa or more, the breakdown voltage value of the main junction (i.e. the opening pressure) It is preferable to set to 0.5 to 0.7 MPa and to set the pressure resistance value (that is, the open pressure) of the sub-joint portion to 0.2 to 0.4 MPa.
When the main joint portion and the sub-joint portion are formed apart from each other, typically, a non-joint portion having substantially no joint strength is formed between the two joint portions. A non-joining part can be easily formed by not heat-pressing the part concerned. Alternatively, a film of resin or other material that does not have adhesiveness with the adhesive layer of the exterior film may be inserted between the exterior films.
As a result of forming the joint valve portion in such a form, the internal pressure generated during normal use is first applied as stress to the sub-joint portion, and the internal pressure (stress) does not reach the main joint portion until the joint strength of the sub-joint portion is substantially lost. . Therefore, the joining strength (pressure resistance performance) of the main joining portion is maintained for a long period of time, and as a result, the desired accurate operation of the joining valve portion is ensured for a long period of time. In this case, the joint strength of the sub-joint portion is set to be equal to or lower than the joint strength of the main joint portion. Although not particularly limited, for example, when the present invention is applied to a film package battery such as a lithium secondary battery, when the pressure resistance value of a normal film sealing portion is 1 MPa or more, the pressure resistance value (that is, the open pressure) of the main junction is set. Set to 0.5 to 0.7 MPa, and the pressure resistance value (i.e., open pressure) of the sub-joint portion is 0.2 to 0.7 MPa (preferably in the range of 0.2 to 0.5 MPa at a lower pressure than the main joint portion ) Is preferable.

One power storage device (film package ) typically includes a pair of main joints and sub-joints, but may include a plurality of pairs of main joints and sub-joints at any position on the outer edge. Alternatively, a plurality of (for example, two or three) sub-joints may be provided for one main joint. For example, in a flat film package power storage device in which the outer edge of the film package is formed of a flange-shaped sealing portion formed by welding exterior films together, a main joint is formed on the outermost side of the flange, and the inner side thereof You may arrange | position one or two or more sub junction parts through a non-joining part.

The method for forming the main joint and the sub-joint (in other words, the method for adjusting the joint strength (pressure resistance performance) of these joints) is not particularly limited. For example, as in the embodiments described later, these joint portions can be formed integrally with an outer edge sealing portion formed by stacking and welding exterior films (laminate films) constituting a film package . In this case, it is good to weld the said films so that the joint strength of the exterior films of the part which comprises these junction parts may become lower than the surrounding sealing part. This can be easily performed by appropriately changing the welding conditions (heating time and / or heating temperature, pressing time and / or degree of pressing, etc.) between the films. For example, when the present invention is applied to a film package battery such as a lithium secondary battery, the film is welded at 200 ° C. or higher (for example, 220 ° C.) at a normal film sealing portion. The film may be formed by welding the films in a lower temperature range, for example, about 170 to 190 ° C. Furthermore, it is good to form a subjoining part by welding films in a temperature range lower than it, for example, about 140-160 degreeC.

Or you may form a main junction part and a subjoint part by inserting another resin-made film between the two exterior films which comprise the sealing part (for example, the said flange part) of the outer edge of a film package . For example, by inserting a film containing a resin component that is difficult to adhere to the adhesive layer of the exterior film between the exterior films, the bonding strength (that is, the pressure resistance value) of the portion can be reduced as compared with the surrounding outer edge sealing portion. In addition, by changing the content of the resin component, the bonding strength can be adjusted and the main bonded portion and the sub bonded portion can be formed. For example, when the adhesive layer of the exterior film (for example, the above three-layer laminate film) is made of polypropylene, a film containing a resin component (for example, polyethylene) that does not have adhesiveness with polypropylene in a predetermined ratio may be used. . And the target main joining part and subjoining part can be formed by thermocompression-bonding the exterior | packing film which inserted and overlapped this film.

As a preferable embodiment of the power storage device disclosed herein, one having a frame (reinforcing member) that holds at least the outer edge of the film package can be given. There is no particular limitation on the shape of the frame as long as it can hold at least the outer edge of the film package . A shape that can be roughly recognized as a frame shape, a box shape, or a case shape can be a typical shape (outer shape) of a frame body included in the power storage device disclosed herein. Further, the material of the frame body may be any material as long as it can be physically reinforced by holding the film package . For example, in addition to various thermoplastic resins or thermosetting resins, a metal frame body is preferably used. be able to.
In a preferred embodiment, the joint valve portion is formed at a position exposed to the outside without being shielded by the frame body so that the function of the joint valve portion is not hindered by the frame body. For example, when the outer edge of the film package is a flange portion, a metal or resin frame (frame body) that is mounted so as to sandwich the flange portion from both sides and a portion corresponding to the joint valve portion has been deleted. The frame is one typical example of the frame disclosed herein.

  Moreover, in one preferable form of the frame body, the frame body has a groove at the inner peripheral end, and the flange portion is inserted into the groove. At the outer peripheral end of the frame, at least a part of the groove is closed. The groove | channel of an inner peripheral end should just be provided according to the formation condition of the flange part of the electrical storage apparatus to mount | wear. The depth of the groove cut from the inner peripheral end of the frame body may be set equal to or slightly deeper than the width of the flange portion accommodated in the groove.
  When the frame body is formed by combining a plurality of frame members, the frame members may be joined together mechanically by engaging means. The frame members are joined with the flange inserted in the groove. When the frame members are mechanically joined to each other by the engaging means, the joining work does not take time. Moreover, when joining frame members using an adhesive agent, you have to work considering the adhesion of the adhesive agent to the film package power storage device. When joining frame members by heat welding, work must be performed in consideration of heat propagation to the flange portion and the electrode body unit. When mechanically joining using the engaging means, it is not necessary to take such considerations, and joining can be performed very easily.

In another preferred embodiment, the function of the joint valve portion is not hindered by the frame body, and in order to better protect the joint valve portion, the joint valve portion is attached to the portion of the frame body facing the joint valve portion. A notch for forming a gap between the joint valve portion and the frame is provided. The notch is formed continuously from the peripheral end of the frame body to the outer peripheral end at a portion facing the joint valve portion. For example, when the outer edge of the film package is a flange portion, the notch is formed in a metal or resin frame (frame body) that is mounted so as to sandwich the flange portion from both sides and is opposed to the joint valve portion. The frame provided with is a typical example of the frame disclosed herein.

Another film package power storage device provided by the present invention is a joint valve portion formed by adhesion of stacked films, and when the internal pressure of the housing portion of the package rises to a predetermined pressure, the adhesion portion A joint valve portion that opens at least a part of the package and communicates the inside and outside of the package is provided at a part of the sealed outer edge of the film package , and includes a frame body configured as disclosed herein. There is no particular limitation on the type and shape of the power storage element included in the manufacturing process and the power storage device. In the present invention, various film package power storage devices (typical examples include a primary battery, a secondary battery, etc., and two or more electrode body units are combined into one film package , as with any of the above-described film package power storage devices. It may be accommodated). As the electrode unit and the exterior film constituting the power storage device, the same ones as those of any of the above-described film package power storage devices can be appropriately adopted. Although the junction valve part in this electrical storage apparatus may contain a main junction part and a subjoint part similarly to the junction valve part in one of the electrical storage apparatuses mentioned above as one preferable aspect, it is not limited to this. For example, the whole joint valve part may be comprised by the exterior film adhere | attached with the substantially same joint strength.

In a preferred embodiment of a power storage device including such a frame, at least a part of the outer edge of the film package constitutes a sealed flange portion made of an overlaid exterior film. And the said frame is mounted | worn so that the said flange part may be inserted | pinched from both sides. In such an aspect, for example, a surface facing the flange portion of the frame body (more preferably, each frame body mounted on both sides of the flange portion) mounted on either side of the flange portion, By forming a notch portion in a portion corresponding to a part of the flange portion (for example, a partial length range in the circumferential direction of the film package ), the flange portion is separated from both sides by a frame body in a portion other than the notch portion. On the other hand, a gap can be selectively formed between the flange and the frame at the notch. As a result, since the internal pressure of the housing portion can be concentrated on the flange portion of the portion facing the notch, the adhesive portion facing the notch can be preferentially opened when the internal pressure is increased. That is, in a power storage device including a frame having a cutout portion having such a configuration, a portion of the flange portion facing the cutout portion can function as a safety valve. Therefore, in the power storage device of this aspect, it can be said that a portion of the flange portion that faces the notch portion constitutes a joint valve portion. In a preferred embodiment, the joint valve portion constitutes a part of the flange portion, and the surrounding flange is formed by an exterior film that is superposed and bonded so that the joint strength is lower than the joint strength of the surrounding flange portion. It is formed integrally with the part. In another preferred embodiment, the joint valve portion is specified as a portion of the flange portion that faces the notch portion, and is superposed and bonded so as to have a joint strength substantially equal to the joint strength of the surrounding flange portion. The outer packaging film is formed integrally with the surrounding flange portion.

The notch portion only needs to be provided so as to be able to form a gap between the joint valve portion and the frame so that the adhesive portion can be opened when the pressure rises. The shape of the notch portion The forming method is not particularly limited. For example, a frame having a shape having a notch may be formed by a conventionally known technique (for a metal frame), injection molding (for a synthetic resin frame), or the like. A notched frame may be prepared, and a notch may be formed by applying a conventionally known technique such as cutting.
In a preferred embodiment, the opening of the gap to the outer peripheral end of the frame body is larger than the opening area of the opening to the peripheral edge of the frame body of the gap formed between the notch portion and the joint valve portion. The opening area of the part is formed to be smaller. By setting it as such a shape, opening | release of the said adhesion part can be advanced smoothly from the inner side of the said junction valve part to the outer side. For example, the inner surface (surface facing the joint valve portion) of at least the notch portion located on the inner periphery side of the frame is a flat or curved tapered surface that narrows from the inner periphery side toward the outer periphery side. It is good to form as a taper surface. 3rd Example mentioned later is an example of an electrical storage measure provided with the frame in which the inner surface of the part (inner peripheral side part) located in a frame body peripheral side among notches is formed as a curved taper surface. The entire inner surface of the notch from the peripheral edge of the frame body to the outer peripheral edge may be formed as a flat or curved tapered surface. In a fourth embodiment and a modification thereof, which will be described later, an example of a power storage device including a frame having a cutout portion in which the entire inner surface of the cutout portion extending from the peripheral end of the frame body to the outer peripheral end is formed as a curved tapered surface. It is.

Thus, a power storage device including a frame having a notch formed so that the opening area of the opening to the frame outer peripheral end is smaller than the opening area of the opening to the peripheral edge of the frame body, it is advantageous when it is intended to introduce the gas discharged from the internal pressure release at accommodating portion to a predetermined exhaust passage. In general, it is preferable to increase the opening area of the notch from the viewpoint of more appropriately functioning the joint valve as a safety valve, while facilitating recovery of the released gas (introduction into the exhaust passage or the like). From this point of view, it is preferable to reduce the opening area of the notch. As described above, by forming the notch so that the opening area to the outer peripheral edge of the frame is smaller than the outer peripheral edge of the frame, for example, the opening area of the notch from the peripheral edge of the frame to the outer peripheral edge is reduced. Compared with the case where it is made substantially constant, the characteristics seen from both these viewpoints can be made compatible at a higher level.
The ratio of the opening area to the frame body peripheral edge and the opening area to the frame peripheral edge is not particularly limited. For example, the opening area to the peripheral edge of the frame body can be made twice or more (preferably four times or more) with respect to the opening area to the outer peripheral edge of the frame body. Further, the width of the opening at the peripheral edge of the frame body can be, for example, 1.5 times or more with respect to the width of the opening at the outer peripheral edge of the frame body, and is preferably set to be twice or more. Further, the height of the opening at the peripheral edge of the frame body can be, for example, 1.5 times or more with respect to the height of the opening at the outer peripheral edge of the frame body, and is preferably 2 times or more.

In a preferred embodiment, the inner surface shape of the notch portion is formed so as not to have a corner portion projecting at an angle of a right angle or less (more preferably, approximately 120 ° or less). By adopting such a shape, it is possible to prevent the film package swelled by the internal pressure from being excessively pressed against the frame (the inner surface of the notch) and being damaged. For example, in the longitudinal section of the notch (the section that is substantially perpendicular to the film package that constitutes the adhesive part), the portion of the inner surface of the notch that is located on the inner periphery of the frame is formed into a gently curved surface A portion located on the outer peripheral side of the frame body is formed in a flat shape, and the boundary between the inner peripheral side inner surface and the outer peripheral side inner surface is formed to have an obtuse angle (preferably 120 ° or more), And the aspect in which the whole inner surface of the notch is formed in a gently curved shape is one typical example of the frame disclosed herein. The gentle curved surface may be a concave surface or a convex surface, or a part thereof may be a concave surface and the other part may be a convex surface. For example, a frame in which the entire inner surface of the notch is formed in a gentle concave shape as a whole (a curved shape that swells toward the open side of the bonded portion) is preferable. Although it has a gentle concave shape as a whole, the degree of dents on the inner surface of the cutout portion is further reduced at the peripheral edge of the frame body and / or in the vicinity of the peripheral edge of the frame body, or it is formed in a flat or loose convex shape. It may be a notch.

In another preferable aspect of the power storage device disclosed herein, the joint valve portion is an opening passage formed in advance between the welded portion formed at a position close to the housing portion and the superimposed film. One end is in contact with the welded portion, and the other end includes an opening passage opened at the outer end of the film package . Since the notch is formed at a portion facing the joint valve portion, the opening passage is formed at a position overlapping the notch when viewed from the plane direction of the frame. Therefore, for example, in a power storage device including a frame body that is mounted so as to sandwich the flange portion from both sides, a notch portion provided on each frame body that is mounted on both sides sandwiches the flange portion. In the power storage device in the opposite mode, the outlet portion of the opening passage (the portion opened at the outer end of the film package ) is positioned inside the opening portion of the notch portion to the outer peripheral end of the frame body. The opening passage is typically provided such that at least the width of the outlet portion of the opening passage is narrower than the width of the opening at the outer end of the frame of the notch. For example, the width of the outlet portion of the opening passage can be set to 70% or less, and further to 50% or less with respect to the width of the opening at the frame body outer end of the notch. The height of the opening passage is not particularly limited, but it is usually appropriate to set the height to be twice or less the thickness of the exterior film. The overall shape of the opening passage is not particularly limited. For example, a cylindrical shape with a substantially circular cross section (cylindrical shape), a cylindrical shape with a substantially elliptical cross section, a cylindrical shape with a substantially rectangular cross section (square cylindrical shape), etc. It can be a shape. Further, the cross-sectional area and / or the cross-sectional shape of the opening passage may be different between the inlet side (welding portion side) and the outlet side of the opening passage. For example, the opening passage can be provided so that the cross-sectional shape of the inlet side and the outlet side is substantially similar, and the cross-sectional area of the outlet side is smaller than that of the inlet side.

  In a preferred aspect of the frame, a groove that accommodates the flange portion penetrates from an inner peripheral end to an outer peripheral end in a part of the frame, and the thickness of the vertical frame from the groove wall of the through groove is different from the other. It should be thinner than the area. In the thin region of the frame, it is possible to prevent creep of the flange portion due to a change in internal pressure during normal use. In the frame, the groove formed in the thin region is less resistant to the force applied in the width direction of the groove than the groove in the other region. When the pressure in the power storage device increases, a force in a direction to release the bonding between the films is applied to the flange portion. When the flange portion is accommodated in the groove of the frame body, the direction of releasing the bonding between the films is equal to the width direction of the groove. When the internal pressure rises abnormally, the creep of the flange portion is selectively generated at a thin portion where the deformation in the width direction is likely to occur. The creep of the flange portion accommodated in the groove of the thin wall portion proceeds, and the bonding between the films is completely released. The groove of the thin part of the frame passes through. If the bonding of the film of the flange portion is released, the pressure in the power storage device is discharged to the outside of the frame. In the flange portion of the power storage device, the region accommodated in the groove of the thin wall portion can function as a safety valve.

  Moreover, in the said thin part, it is good that the center part of the outer peripheral direction is the thinnest from the inner peripheral side toward the outer peripheral side. When the central portion of the thin portion is the thinnest, the creep of the flange portion proceeds from the central portion of the thin portion. When the region accommodated in the groove of the thin portion functions as a safety valve, the size of the communication hole formed at the time of gas discharge can be minimized. Examples of such a shape include a dent having a curved arch-shaped cross section, and a V-shaped cross section shape that gently slopes toward the center.

  Several preferred embodiments of the present invention will be described below with reference to the drawings, but the present invention is not intended to be limited to those shown in the drawings.

<First embodiment>
First, the film package power storage device 1 according to the first embodiment will be described with reference to FIGS. The present embodiment shows a lithium secondary battery as a typical example of the power storage device 1. FIG. 1 is a perspective view schematically showing an outline of a film package power storage device 1 according to the present embodiment. FIG. 2 is a partially enlarged view showing the joint valve portion 18 according to the present embodiment. 3 is a cross-sectional view taken along the line III-III in FIG. 2 and schematically shows a cross-sectional structure of the joint valve portion 18.
As shown in these figures, the film package power storage device 1 according to the present embodiment generally has a film package 10, a frame body 20 for holding the outer edge of the package 10 (outer periphery), housed in a package 10 The electrode body unit is not shown, and a positive electrode terminal 3 and a negative electrode terminal 5 which are a pair of thin plate-like external terminals connected to the electrode body unit.

The film package 10 is constituted by two exterior films 11 and 12 that are overlaid, as in this type of general film package flat battery. As shown in FIG. 1, an electrode body housing portion 13 is formed in the center of the package 10 as viewed from the plane side (upper side in the figure), and extends in a rectangular shape on both the front and back surfaces. The accommodating portion 13 accommodates an electrode body unit and an electrolyte having a predetermined shape. On the other hand, a belt-like flange portion (sealing portion) 14 sealed by thermal welding of the exterior films 11 and 12 is formed at an outer edge (outer periphery) portion surrounding the accommodating portion 13. Thereby, the airtightness in the accommodating part 13 in the film package 10 is ensured. A joint valve portion 18 according to the present embodiment is formed in a part of the flange portion 14. This will be described later.
As shown in FIG. 1, the positive electrode terminal 3 and the negative electrode terminal 5 are joints of the exterior films 11 and 12, and project outward from the flange portion 14 through the package 10. A current can be taken out from the electrode body unit through the positive electrode terminal 3 and the negative electrode terminal 5.

The exterior films 11 and 12 according to the present embodiment are constituted by a conventional general three-layer structure laminate film. That is, as shown in FIG. 3, the exterior films 11 and 12 include an outer surface (protective layer) 7 made of polyethylene terephthalate resin, a barrier layer 8 made of aluminum foil, and an adhesive layer 9 made of polypropylene resin. It consists of and. The film package 10 is constructed by bringing the adhesive layers 9 of the laminate films 11 and 12 face each other and the peripheral edge portions are thermally welded by a general heating means (for example, a heat press machine).

The electrode body unit according to the present embodiment can be used as it is in the form used in a conventional film package battery. That is, it is a general wound electrode body unit produced by laminating a positive electrode sheet and a negative electrode sheet (not shown) together with a separator and then winding them. An aluminum positive electrode terminal 3 and a copper negative electrode terminal 5 are drawn out from one end face of the wound electrode body unit. The configuration itself of the electrode body unit does not limit the present invention, and may be configured using various conventionally used materials. For example, the positive electrode sheet can be formed by applying a positive electrode active material layer for a lithium secondary battery on a long positive electrode current collector. A metal foil such as an aluminum foil is preferably used for the positive electrode current collector. As the positive electrode active material, one kind or two or more kinds of substances conventionally used in lithium secondary batteries can be used without any particular limitation. Preferable examples include LiMn ₂ O ₄ , LiCoO ₂ , LiNiO _{2 and the} like. On the other hand, the negative electrode sheet may be formed by applying a negative electrode active material layer for a lithium secondary battery on a long negative electrode current collector. A metal foil such as a copper foil is preferably used for the negative electrode current collector. As the negative electrode active material, one or two or more kinds of materials conventionally used in lithium secondary batteries can be used without any particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides. Suitable separator sheets used between the positive and negative electrode sheets include those made of a porous olefin resin.

The film package 10 contains a liquid electrolyte (electrolytic solution) (not shown) together with the electrode body unit, and is impregnated in the electrode body unit. The electrolytic solution to be used is not particularly limited. For example, 1 mol / L as a lithium salt in a mixed solvent of diethyl carbonate (DEC) and ethylene carbonate (EC) (for example, a mixed solvent in which DEC: EC is in a mass ratio of 7: 3). A nonaqueous electrolytic solution in which LiPF ₆ is dissolved can be preferably used.

The frame body 20 according to the present embodiment is a frame-shaped member made of a synthetic resin (polypropylene, polystyrene, polyethylene, etc.) having a relatively high rigidity. As shown by a chain line in FIG. 1, the frame body 20 according to the present embodiment is mounted by sandwiching almost the entire circumference of the flange portion 14 of the film package 10 from both sides. However, the portion 22 opposite to the portion where the joint valve portion 18 is formed is deleted so that the joint valve portion 18 is exposed without being shielded. In this way, by providing the missing portion 22 and mounting the frame body 20 with the flange portion 14 sandwiched therebetween, the stress can be easily concentrated on the joint valve portion 18 when the internal pressure of the accommodating portion 13 rises. Become. In particular, in this embodiment, the missing portion 22 and the joint valve portion 18 of the frame body 20 are formed substantially at the center of one long side flange portion 14 of the rectangular accommodating portion 13 to which stress is easily applied. For this reason, it is possible to prevent a decrease in the bonding strength at the flange portion 14 and to transmit the internal pressure (stress) to the bonding valve portion 18 selectively and efficiently. Furthermore, the mechanical strength of the power storage device 1 as a whole can be improved by the frame 20.

Next, the joint valve portion 18 (internal pressure release mechanism) according to the present embodiment will be described in detail. As shown in FIGS. 1 and 2, the joint valve portion 18 according to the present embodiment is substantially at the center of the long side of the flange portion 14 of the film package 10 (typically, the long side of the flange portion 14 as shown in the figure). The length corresponding to 5% to 20% of the side total length). Specifically, a rectangular main joint portion 15 is formed along the outer edge of the flange portion 14 when viewed from the plane side (upper side in the drawing). On the inner side, a sub-joint portion 16 is formed in a rectangular shape with a non-joint portion 17 having substantially the same shape interposed therebetween. Specifically, about one third of the flange portion 14 in the inner and outer (width) direction is the main joint portion 15, and about one third in the width direction is the non-joint portion 17. About one third is the sub-joint portion 16. An inner long side end portion of the sub-joint portion 16 coincides with the inner edge of the flange portion 14. In other words, the inner edge of the sub-joining portion 16 contacts the accommodating portion 13 (FIG. 3).

The main joint portion 15 according to this embodiment is joined with a joining strength (pressure resistance performance) according to the pressure so as to be opened when the internal pressure rises to a predetermined pressure (about 0.6 MPa in this embodiment). ing. In this embodiment, the pressure resistance performance of the surrounding flange portion 14 is about 1.0 MPa. On the other hand, the joint strength of the sub-joint portion 16 is set to about 0.3 MPa.
The pressure resistance value (bonding strength) of each joint can be determined by appropriately adjusting the temperature, pressure, processing time, and the like during heat welding. For example, in this embodiment, the flange portion 14 having a pressure resistance of about 1.0 MPa is formed by setting the heating temperature during welding of the exterior films 11 and 12 to 220 ° C., and the film heating temperature is set to 180 ° C. By setting, the main joint 15 having a withstand pressure of about 0.6 MPa can be formed, and by setting the film heating temperature to 150 ° C., the sub-joint 16 having a withstand pressure of about 0.3 MPa can be formed. In addition, the shaded portion in FIG. 3 schematically shows the bonding state of the main bonding portion 15 and the sub bonding portion 16 formed by bonding the exterior films 11 and 12, and is perpendicular to the bonding surface. The wider the width, the higher the bonding strength (that is, withstand voltage).

Moreover, in the junction valve part 18 which concerns on a present Example, the non-joining part 17 is provided in the boundary part of the main junction part 15 and the subjoint part 16, and both junction parts are isolate | separated clearly. Thereby, the internal pressure generated during normal use is first applied directly to the sub-joint portion 16, but the non-joint portion 17 can block the pressure from being transmitted to the main joint portion 15. Therefore, the pressure resistance performance of the joint valve 18 itself (that is, the main joint 15 is opened as a safety valve when a predetermined internal pressure rises) can be maintained over a long period (for example, 10 years or more, preferably 15 years or more). .

<Second embodiment>
Next, based on FIG.4 and FIG.5, the film package electrical storage apparatus 31 which concerns on 2nd Example is demonstrated. The power storage device 31 according to the present embodiment is a film package lithium secondary battery having the same configuration as that of the first embodiment. FIG. 4 is a partially enlarged view showing the vicinity of the joint valve portion 38 according to the present embodiment. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. The portions other than the joint valve portion 38 that characterizes the present embodiment are the same as those in the first embodiment described above (the same reference numerals are given in the drawing), and redundant descriptions thereof are omitted.

Unlike the first embodiment, the joint valve portion 38 according to the present embodiment does not form the non-joint portion 17 (see FIG. 2) between the main joint portion 35 and the sub-joint portion 36.
That is, a rectangular main joint portion 35 is formed along the outer edge of the flange portion 14 when viewed from the plane side (upper side in the drawing). A sub-joining portion 36 having substantially the same shape is formed inside thereof. Specifically, about half of the outer side in the inner and outer (width) direction of the flange portion 14 is the main joint portion 35, and about one half of the inner side in the width direction is the sub-joint portion 36. The long side end portion inside the sub-joint portion 36 coincides with the inner edge of the flange portion 14. That is, the inner edge of the sub-joining part 36 contacts the accommodating part 13 (FIG. 5).

As in the first embodiment, the main joint portion 35 according to this embodiment is formed so that the withstand pressure is about 0.6 MPa by setting the heating temperature at the time of welding the exterior films 11 and 12 to 180 ° C. On the other hand, the sub-joint part 36 is formed so that the pressure resistance becomes about 0.3 MPa by setting the film heating temperature to 150 ° C. In addition, the shaded portion in FIG. 5 schematically shows the joining state of the main joint portion 35 and the sub-joint portion 36 formed by bonding the exterior films 11 and 12, and actually the boundary between these joint portions. Are not clearly categorized and identified as shown.
According to such a configuration, creep that may occur during normal use first proceeds in the sub-joint portion 36 with low joint strength, and the joint strength in the main joint portion 35 is not lowered until a crack or other open portion occurs in the sub-joint portion 36. Does not occur. Therefore, the desired pressure resistance performance can be maintained over a long period of time also by the joint valve portion 38 according to the present embodiment.

<Third embodiment>
Next, the film package power storage device 41 according to the third embodiment will be described with reference to FIGS. The power storage device 41 according to the present embodiment is a film package lithium secondary battery in which the structure of the joint valve portion 44 and the structure of the frame 50 are different from those of the first embodiment described above. In addition, since the structure of parts other than the joint valve part 44 and the frame 50 which characterize the present embodiment is the same as that of the first embodiment described above, the same reference numerals as those in the first embodiment are given in the drawing, and these are the same. The duplicate description of is omitted.

FIG. 6 is an exploded perspective view showing the overall structure of the power storage device 41 according to the present embodiment, and FIG. As shown in these figures, the power storage device 41 according to this embodiment, the film package 42, a rectangular frame-shaped frame which is mounted by sandwiching the substantially entire circumference from both sides of the flange portion 14 of the film package 42 A body 50. More specifically, the frame body 50 includes a first frame body 50A attached to one side of the flange portion 14 and a second frame body 50B attached to the other side of the flange portion 14, and these frames. The flange portion 14 is sandwiched between the bodies 50A and 50B.
In a part of the frame 50 that is opposed to a part in the circumferential direction of the flange portion 14 (the central part of one long side), the frame 50A, 50B extends from the inner peripheral end to the outer peripheral end of the frame. A notch 52 is formed, whereby a gap is formed between the flange 14 and the frame 50. As shown well in FIG. 7, the notch 52 provided in the first frame 50A and the notch 52 provided in the second frame 50B are substantially symmetrical with the flange portion 14 as the symmetry plane. It is formed to become. Hereinafter, the shape of the notch 52 will be described in more detail mainly using the frame 50A as an example.

As shown in FIG. 6 and FIG. 7, the inner peripheral side portion 522 located on the inner peripheral side of the frame 50 </ b> A in the notch 52 is the width of the notch from the inner peripheral side to the outer peripheral side of the frame 50 </ b> A. Further, the depth is gradually reduced. The inner surface of the inner peripheral portion 522 is a concave surface (curved surface) as a whole. However, the shape of the inner surface gradually changes to a convex shape near the inner peripheral end of the frame 50A. On the other hand, the outer peripheral side portion 524 located on the inner peripheral side of the frame body 50A in the cutout portion 52 has a substantially constant cross-sectional shape from the inner peripheral side to the outer peripheral side, and the cross-sectional shape is substantially trapezoidal. It is formed as follows. As shown in FIG. 7, the boundary between the inner peripheral portion 522 and the outer peripheral portion 524 has an obtuse angle of 120 ° or more. The ratio of the length of the inner peripheral side portion 522 and the length of the outer peripheral side portion 524 out of the length connecting the inner peripheral end and the outer peripheral end of the frame 50A is, for example, inner peripheral portion: outer peripheral portion = 30: 70 to It can be in the range of 90:10, usually in the range of 40:60 to 80:20, and preferably in the range of 50:50 to 70:30. In this embodiment, as well shown in FIG. 7, the ratio of the length of the inner peripheral portion 522 to the length of the outer peripheral portion 524 is approximately 60:40.
As shown in the drawing, the width of the opening at the inner peripheral edge of the cutout portion 52 (inner peripheral portion 522) is a length corresponding to approximately 20 to 40% of the total length of the long side of the flange portion 14. . The width of the opening at the outer peripheral edge of the frame body of the notch 52 (outer peripheral portion 524) is about 25 to 50% of the width of the opening at the inner peripheral edge of the notch 52 in the frame. Further, since the cutout portion 52 is formed so as to reach the entire thickness of the frame body 50A via a gently curved surface (convex surface) at the peripheral edge of the frame body, the height of the opening at the peripheral edge of the frame body is the frame body. It is almost equal to the thickness of 50A. On the other hand, the width of the opening at the outer peripheral edge of the cutout 52 is about 10 to 40% of the thickness of the frame 50A. The opening area at the outer peripheral edge of the frame body of the notch 52 is ¼ or less, and typically ８ or less of the opening area at the peripheral edge of the notch 52 in the frame body.

The flange portion 14 in the power storage device 41 according to the present embodiment has a bonding strength (pressure resistance performance) in which the pressure resistance performance (that is, the pressure resistance performance of the film package 10 alone) in a state where the frame body 50 is not attached is about 0.6 MPa. ). However, the pressure resistance performance is reinforced by attaching the frame body 50 that sandwiches the flange portion 14 from both sides except for the portion of the flange portion 14 that faces the notch portion 52. Therefore, in a state where the frame body 50 is mounted, the internal pressure of the housing portion 13 selectively acts on the flange portion 14 at a portion facing the notch portion 52. That is, in the present embodiment, the flange portion 14 at a portion located between the notch portion 52 provided in the frame body 50A and the notch portion 52 provided in the frame body 50B functions as the joint valve portion 44.

  In the joint valve portion 44, the exterior films 11 and 12 are bonded with the above-described predetermined joint strength to form a weld portion 46. Further, in the joint valve portion 44, a substantially central portion in the width direction (long side direction of the flange portion 14) extends straight from a position slightly closer to the outer periphery from the center between the inner peripheral end and the outer peripheral end of the joint valve portion 44. A non-bonded portion where the exterior film 11 and the exterior film 12 are not bonded is provided in a range reaching the outer peripheral end. One end (inner peripheral end) is in contact with the welded portion 46 and the other end (outer peripheral end) is opened at the outer end of the joint valve portion 44 by the exterior films 11 and 12 constituting the non-joined portion and the welded portion 46 surrounding the outer film 11 and 12. An opening passage 48 is formed. This opening passage may be a portion of the notch 52 that forms the opening passage 48 in a portion facing the outer peripheral portion 524 of the notch 52, and the inner peripheral end of the opening passage 48 is the inner peripheral portion. It may extend to a portion facing 522. Typically, as shown in FIG. 7, the inner peripheral end of the opening passage 48 is in the vicinity of the boundary between the inner peripheral portion 522 and the outer peripheral portion 524 or at a position where it enters the outer peripheral portion 524 slightly from the boundary. Thus, the joint valve portion 44 is formed.

The operation of the joint valve portion 44 in the power storage device 41 having such a configuration will be described with reference to FIGS. 8 and 10, the frame 50 is not shown in order to make it easy to see the state in the vicinity of the joint valve portion 44.
When the internal pressure of the accommodating portion 13 rises, the portion other than the joint valve portion 44 of the flange portion 14 is sandwiched by the frame body 50, so that the pressure acts on the joint valve portion 44 in a concentrated manner. When the internal pressure of the accommodating portion 13 exceeds the bonding strength of the welded portion 46, the adhesion of the welded portion 46 is released. The opening proceeds from the inner peripheral side to the outer peripheral side of the welded portion 46, and the film package 10 swells outward by the internal pressure at the open portion. Here, the notch 52 is formed such that the inner surface is formed of a gently curved surface (inner peripheral portion 522) and a flat surface (outer peripheral portion 524), and there is no corner protruding at a right angle or less. Has been. Therefore, even if the swelled exterior films 11 and 12 are pressed against the inner wall of the notch 52 by the internal pressure, there is no fear that the exterior films 11 and 12 are damaged. Further, the inner peripheral side portion 522 of the notch 52 is formed so that the width and depth of the notch gradually decrease from the inner peripheral side toward the outer peripheral side, so that the opening is made from the inner side to the outer side. It can proceed smoothly.

When the opening of the welded portion 46 proceeds and the open portion reaches the inner peripheral side end of the opening passage 48 (as shown in FIGS. 8 to 10), the inside and outside of the film package 10 are formed by the opening portion and the opening passage 48. A communication path is formed for communicating the. This internal pressure of the housing portion 13 is opened by the. In other words, gas is released from the inside of the accommodating portion 13 . As described above, according to the power storage device 41 of the present embodiment, even when the position at which the opening of the welded portion 46 proceeds most quickly varies in the width direction of the joint valve portion 44 (long side direction of the flange portion 14), The position of the outlet (outer peripheral end) of the communication passage can be made constant (more specifically, the position of the outlet of the opening passage 48 formed in advance). Further, it is possible to prevent the outlet of the communication passage from becoming excessively large, and typically, the size of the outlet can be defined by the size of the outlet of the opening passage 48. Since the power storage device 41 of the present embodiment can accurately define the position and size of the gas released from the inside of the accommodating portion 13 as described above, the discharged gas is discharged to a predetermined exhaust as shown in FIG. It can be preferably used in a mode of being introduced into the passage 56. For example, the gas released from the inside of the accommodating portion 13 is efficiently passed through the exhaust introduction hole 562 formed at a position opposite to the outer peripheral end of the opening passage 48 in the exhaust passage 56 (with no leakage or exhaust). Can be introduced without unnecessarily increasing the opening area of the introduction hole 58.

  In addition, the shape of the opening channel | path 48 in the said Example is not specifically limited. For example, a cylindrical opening passage as shown in FIG. 11 (a), a cylindrical opening passage having a substantially oval cross section as shown in FIG. 11 (b), and a rectangular tube shape as shown in FIG. 11 (c). Open passages, etc. For example, as shown in FIG. 11 (d), the inner peripheral side has a rectangular tube shape, and an opening passage formed in a shape (tapered shape) in which the opening area gradually decreases toward the outer peripheral end near the outer peripheral end. It may be.

<Fourth embodiment>
A film package power storage device 61 according to the fourth embodiment will be described with reference to FIGS. 12 and 13. The power storage device 61 according to the present embodiment is a film package lithium secondary battery in which the structure of the frame body 70 (more specifically, the shape of the cutout portion 72) is different from that of the third embodiment described above. Since the configuration of the portion other than the frame body 70 characterizing the present embodiment is the same as that of the third embodiment described above, the same reference numerals as those of the third embodiment are given in the drawing, and the duplicate description thereof is omitted. .

FIG. 12 is a perspective view showing the overall structure of the power storage device 61 of this embodiment. This power storage device 61 includes a film package 42 configured in the same manner as in the third embodiment, and a rectangular frame-shaped frame body 70 that is mounted by sandwiching almost the entire circumference of the flange portion 14 of the film package 42 from both sides. Is provided. The frame body 70 includes a first frame body 70A mounted on one side of the flange portion 14 and a second frame body 70B mounted on the other side of the flange portion 14, and these frame bodies 70A and 70B. The flange portion 14 is sandwiched between the two.
In a portion of the frame body 70 that is opposed to a part in the circumferential direction of the flange portion 14 (the central portion of one long side), the frame bodies 70A and 70B respectively reach from the inner peripheral edge to the outer peripheral edge of the frame body. A notch 72 is formed, whereby a gap is formed between the flange portion 14 and the frame body 70. The notch 72 provided in the first frame 70A and the notch 72 provided in the second frame 70B are formed so as to have a substantially symmetrical shape with the flange portion 14 as a symmetry plane.

FIG. 13 is a perspective view schematically showing the shape of the frame 70A (the frame 70B has substantially the same shape as the frame 70A). As shown in the figure, the notch 72 is formed as a gently curved tapered surface in which the entire inner surface from the inner peripheral end to the outer peripheral end of the frame body 70A gradually narrows from the inner peripheral end to the outer peripheral end. Yes. The tapered surface has a concave shape as a whole. However, in the vicinity of the inner peripheral edge of the frame 70A, the shape of the inner surface gradually changes to a convex shape, like the frame 50 of the third embodiment shown in FIG. In addition, the inner surface shape of the notch 72 is gradually changed to a convex shape near the outer peripheral edge of the frame 70B. Note that the width, height, and area of the openings at the inner peripheral edge and the outer peripheral edge of the notch 72 are the same as those of the frame 50 in the third embodiment described above. Can be a degree. The shape of the opening at the outer peripheral edge of the frame of the notch 72 can be generally arcuate as shown in FIG.
According to the power storage device 61 including the frame body 70 in which the cutout portion 72 having such a shape is formed, the same effect as in the third embodiment described above can be realized. In the present embodiment, since the entire inner surface of the notch portion 72 is formed in a gently curved shape, the operation of the joint valve portion 44 as a safety valve can be performed more smoothly.

  In addition, the aspect which comprises the whole inner surface of the notch part 72 in a gentle curved surface shape is not restricted to the aspect in which this inner surface exhibits a concave shape as a whole, as shown in FIG. For example, as a modification of the fourth embodiment, as shown in FIG. 14, the entire inner surface of the notch 92 is formed as a gently curved tapered surface that narrows from the inner peripheral end to the outer peripheral end of the frame 90, And it is good also as the electrical storage apparatus 81 of the aspect in which this taper surface exhibits a convex-shaped shape as a whole.

  <Fifth embodiment>
  The power storage device 101 of this embodiment will be described with reference to FIGS. The power storage device 101 differs from the other embodiments mainly in the structure of the frame 150. Descriptions that are the same as those in the other embodiments except for the frame will be omitted.

FIG. 15 is a perspective view of the power storage device 101 including the frame 150. The power storage device 101 uses a film package 110 that houses an electrode body unit therein. FIG. 16 is an exploded perspective view showing the positional relationship between the first half frame 156, the second half frame 158, and the film package 110. FIG. 17 is a plan view seen from the surface from which the positive terminal 103 and the negative terminal 105 are drawn.
As shown in FIG. 15, the frame 150 is attached along the outer periphery of the film package 110. The frame 150 has a frame shape having four side portions 170, 172, 174, and 176. As shown in FIGS. 15 and 16, the positive electrode terminal 103 and the negative electrode terminal 105 are drawn from the outer peripheral surface of the side portion 170. A through groove 154 extending from the inner peripheral surface side to the outer peripheral surface side is formed between the positive electrode terminal 103 and the negative electrode terminal 105 of the side portion 170. The side portion 170 is formed with thin regions 152 and 152 that are curved toward the inner wall of the through groove 154. The thin regions 152 and 152 are formed by being cut from both sides sandwiching the through hole 154. As will be described in detail later, the region sandwiched between the thin regions 152 in the flange portion 114 of the film package 110 functions as a safety valve 122 that is preferentially opened when the internal pressure of the power storage device 101 increases. When the internal pressure rises abnormally, the through groove 154 functions as a gas discharge hole.

  As shown in FIGS. 15 and 16, the frame 150 includes a substantially U-shaped first half frame 156 and a substantially U-shaped second half frame 158. The first half frame 156 includes a side portion 170, a half region 172 A of the side portion 172, and a half region 176 A of the side portion 176. The second half frame 158 includes a side part 174, a half area 172 B of the side part 172, and a half area 176 B of the side part 176.
  As shown in FIG. 16, locking holes 161 are provided at the outer peripheral ends of the side portions 172 </ b> A and 176 </ b> A of the first half frame 156. Locking claws 159 are provided on the outer peripheral ends of the side portions 172B and 176B of the second half frame 158. By engaging the locking hole 161 and the locking claw 159, the half area 172A and the half area 172B are firmly joined. Similarly, the half region 176A and the half region 176B are firmly joined. 160 shows a state where the locking hole 161 and the locking claw 159 are combined. The frame-shaped frame 150 is completed by the above engagement process.

  As shown in FIG. 16, grooves 162 and 166 cut from the inner peripheral end toward the outer peripheral side are formed in the frame 150. The groove 162 is provided at the inner peripheral end of the first half frame 156. The groove 166 is provided at the inner peripheral end of the second half frame 158. The groove 162 and the groove 166 are continuous in the circumferential direction by the above-described engagement process.
  19 is a cross-sectional view taken along line XIX-XIX in FIG. FIG. 19 shows a state in which the flange 114 is accommodated in the groove 162 of the first half frame 156. In FIG. 19, the cross-sectional shape of the frame 150 is also shown. As shown in FIG. 19, the depth of the groove 162 is substantially equal to the width of the flange portion 114 of the power storage device 101. The flange portion 114 of the power storage device 101 is sandwiched and accommodated in the groove 162. The groove 166 of the second half frame 158 also accommodates the flange 114 with the same configuration.
  The side portion 170 of the first half frame 156 includes a positive electrode terminal hole 163 for drawing out the positive electrode terminal 103, a negative electrode terminal hole 165 for drawing out the negative electrode terminal 105, and a through groove as holes that continue from the inner peripheral end to the outer peripheral end. 154. The terminal holes 163 and 165 and the through groove 154 are continuous with the groove 162.

  Next, a holding method and a holding state of the power storage device 101 in the frame 150 will be described.
  The power storage device 101 has the positive electrode terminal 103 and the negative electrode terminal 105 pointed toward the inner peripheral end of the side portion 170 of the first half frame 156. The flange 114 is inserted into the groove of the first half frame 156 and slides. Next, the positive electrode terminal 103 and the negative electrode terminal 105 are inserted into the positive electrode terminal hole 163 and the negative electrode terminal hole 165 provided in the side portion 170. Next, the remaining flange 114 is inserted into the groove 166 of the second half frame 158. Then, the locking part 161 of the first half frame 156 and the locking claw 161 of the second half frame 158 are engaged, and the first half frame 156 and the 158 are joined. Then, the power storage device 101 is held in the frame 150.

  Since the main frame 150 uses the first half frame 156 and the second half frame 158, the frame 150 can be easily attached to the power storage device 101. The first half frame 156 and the second half frame 158 are joined to avoid the corner portion of the power storage device 101. The corner portion of the power storage device 101 is most easily affected by the fluctuation of the internal pressure of the power storage device 101. By forming the joint portion between the first half frame body 156 and the second half frame body 158 so as to avoid the corner portion, the restraining force applied to the flange portion 114 portion of the corner portion can be kept uniform. According to the configuration of the main frame 150, mounting to the power storage device 101 is easy, and creep of the flange portion 114 is suppressed.

  Next, the safety valve structure of the power storage device 101 will be described with reference to FIGS. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 16 and shows a safety valve structure during normal use. FIG. 20 is an enlarged plan view of the periphery of the thin portion 152 during normal use. FIG. 21 is an enlarged plan view of the periphery of the thin portion 152 when the internal pressure rises abnormally.
  As described above, the frame 150 is formed with the thin portion 152 having a small thickness from the joint surface of the flange 114.
  As shown in FIG. 20, a through groove 154 that communicates from the inner periphery side to the outer periphery side is formed in the range where the thin portion 152 is formed. The opening shape of the through-groove 154 is a rectangle that has an extremely long outer peripheral direction during normal use when viewed from the outer peripheral end from the outside. In FIG. 20, the symbol h indicates the thickness of the flange 144. The groove widths of the grooves 162 and 166 in the frame 150 are substantially equal to h. The flange portion 114 is restrained while being sandwiched between the groove walls of the grooves 162 and 166. The opening of the through groove 154 is slightly wider than the thickness h of the flange portion 114. A space 155 is formed between the outer peripheral end of the flange 114 (joining valve portion 122) and the groove wall of the through groove 154. Since the opening of the through groove 154 is wider than the thickness of the flange 114, the gas release when the internal pressure is released becomes smooth. In the thin portion 152 of the frame body, the thinnest portion in the vertical direction from the groove wall of the through groove 154 is L1. In other regions, the thickness in the vertical direction from the wall surfaces of the grooves 162 and 166 is W1. Creep in most areas of the flange portion 114 is suppressed by the thickness of W1. On the other hand, the creep of the area | region which contact | connects the thin part 152 of the flange part 114 is suppressed by the thickness of L1. The ability to suppress creep is higher in the region having the thickness of W1. The force which restrains the flange part 114 of the thin part 152 becomes weaker than another area | region. In the flange portion 114 of the power storage device 101, the region sandwiched between the thin regions 152 functions as a joint valve portion 122 (safety valve) that is preferentially opened when the internal pressure of the power storage device 101 rises. When the internal pressure increases, the through groove 154 functions as a gas discharge hole. In the region of the thin wall 152 of the main frame 150, creep of the joint valve portion 122 due to a change in internal pressure during normal use does not occur.

  As shown in the cross-sectional view during normal use in FIG. 18, the exterior film 111 is in contact with one wall surface, and the exterior film 112 is in contact with the other wall surface. The end portion of the joint valve portion 122 is slightly on the inner peripheral side than the outer peripheral end of the frame body 150. A space 155 is formed between the inner wall of the through groove 154 and the films 111 and 112 at the end of the joint valve portion 122. As described above, the space 155 is formed to secure a gas passage when the joint valve portion 122 is opened. Along with the formation of the space 155, in the thin wall portion 152, an edge region 151 that is thinner in the periphery of the opening on the outer peripheral side of the through hole 154 is formed.

  In the frame 150, the through groove 154 formed in the thin portion 152 is less resistant to the force applied in the width direction of the groove than the grooves 162 and 166 in other regions. When the pressure in the power storage device 101 increases, a force in a direction to release the bonding between the films 111 and 112 is applied to the flange portion 114. When the internal pressure rises abnormally, the creep of the flange portion 114 is selectively generated at the thin-walled portion 152 that tends to be deformed in the width direction. Further, as shown in the plan view of FIG. 21, the groove width of the through groove 154 is increased following the expansion of the films 111 and 112. FIG. 22 is a sectional view taken along line XXII-XXII in FIG. As shown in the sectional view of FIG. 22, a space 155 is formed between the ends of the films 111 and 112 and the through groove 154. In the thin portion 152, an edge region 151 is formed with a thinner portion around the opening on the outer peripheral side of the through hole 154. Since the edge region 151 is thin, a gas passage when the internal pressure is released is reliably ensured.
  Further, the thin portion 152 has the thinnest central portion in the contour direction. The creep phenomenon of the safety valve 122 proceeds from the central portion of the thin portion 152. When the internal pressure rises and gas is released, the size of the communication hole formed at the time of gas discharge can be minimized. Excessive leakage of electrolytic solution or the like from the storage unit 113 of the power storage device is suppressed. In addition, in the flange part 114, the adhesive strength of the area | region which comprises the safety valve 122 should just be equal to or less than the joint strength of another area | region.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in each of the above embodiments, a lithium secondary battery has been described. However, the present invention generally relates to power storage devices, for example, other types of secondary batteries such as nickel metal hydride batteries and nickel cadmium batteries, and various power storage devices such as electric double layer capacitors. It can also be applied to. The active material, current collector and terminal constituting the electrode unit, the material such as the separator, the composition of the electrolytic solution, and the like can be appropriately determined according to the type of the power storage device.
In each of the above embodiments, one sub-joint portion is provided for one main joint portion. However, the present invention is not limited to this. For example, one main joint portion and two or three or more in the width direction of the flange. You may provide a subjoining part (preferably a non-joining part is formed between joining parts).
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

It is the perspective view which showed typically the film package electrical storage apparatus (lithium secondary battery) which concerns on one Example. It is the expansion perspective view which showed typically the form of the principal part (joining valve part) of the electrical storage apparatus shown in FIG. It is sectional drawing in the III-III line of FIG. It is the expansion perspective view which showed typically the form of the junction valve part of the film package electrical storage apparatus which concerns on another one Example. It is sectional drawing in the VV line of FIG. It is the disassembled perspective view which showed typically the whole structure of the film package electrical storage apparatus which concerns on another one Example. It is sectional drawing in the VII-VII line of FIG. State is a perspective view schematically showing when the internal pressure is opened in the energy storage device shown in FIG. It is sectional drawing in the IX-IX line of FIG. It is the perspective view which showed typically the positional relationship of the electrical storage apparatus shown in FIG. 8, and an exhaust passage. (A), (b), (c), and (d) are the perspective views which each illustrate typically the shape of the opening channel | path in the electrical storage apparatus shown in FIG. It is the perspective view which showed typically the whole structure of the film package electrical storage apparatus which concerns on another one Example. It is the perspective view which showed typically the frame which comprises the electrical storage apparatus shown in FIG. It is sectional drawing which showed typically the modification of the electrical storage apparatus shown in FIG. It is the perspective view which showed typically the whole structure of the film package electrical storage apparatus which concerns on another one Example. FIG. 16 is an exploded perspective view of the power storage device shown in FIG. 15. FIG. 16 is a plan view of a terminal lead surface of the power storage device shown in FIG. 15. It is sectional drawing in the XVIII-XVIII line of FIG. It is sectional drawing in the XIX-XIX line | wire of FIG. FIG. 16 is an enlarged plan view schematically showing a safety valve portion of the power storage device shown in FIG. 15. FIG. 16 is an enlarged plan view schematically showing a state of the safety valve portion of the power storage device shown in FIG. 15 when the internal pressure is released. It is sectional drawing in the XXII-XXII line | wire of FIG.

Explanation of symbols

1, 31, 41, 61, 81, 101: Film package power storage device (lithium secondary battery)
10, 42, 110: film package 11, 12, 111, 112: exterior film (laminate film)
13, 113: Housing part 14, 114: Flange part 15, 35: Main joint part 16, 36: Sub joint part 17: Non-joint part 18, 38, 44, 122: Joint valve part (safety valve)
20, 50, 70, 90, 150: Frame 22: Deletion portion 46: Welding portion 48: Opening passage 52, 72, 92: Notch portion 152: Thin portion

Claims (14)

A film exterior type power storage device comprising an electrode body unit having a positive electrode and a negative electrode, and a film exterior body in which a space for accommodating the electrode body unit is formed. An internal pressure release mechanism having the following configuration:
In a part of the sealed outer edge of the exterior body, a joint valve portion formed by adhesion of the overlapped films, and when the internal pressure of the electrode body unit accommodation space of the exterior body rises to a predetermined pressure At least a part of the adhesive portion is opened to have a joint valve portion for communicating the inside and outside of the exterior body;
The joint valve portion includes a main joint portion having a joint strength corresponding to the predetermined pressure, and a sub-joint portion having a joint strength lower than the main joint portion; and the sub-joint portion is more than the main joint portion. The internal pressure of the electrode unit housing space is arranged at a position close to the electrode body housing space, and the internal pressure is applied to the sub-joining portion during normal use. The main joint and the sub-joint are formed at a position added to the part;
A power storage device is provided. A film exterior type power storage device comprising an electrode body unit having a positive electrode and a negative electrode, and a film exterior body in which a space for accommodating the electrode body unit is formed. An internal pressure release mechanism having the following configuration:
In a part of the sealed outer edge of the exterior body, a joint valve portion formed by adhesion of the overlapped films, and when the internal pressure of the electrode body unit accommodation space of the exterior body rises to a predetermined pressure At least a part of the adhesive portion is opened to have a joint valve portion for communicating the inside and outside of the exterior body;
The joint valve portion includes a main joint portion having a joint strength corresponding to the predetermined pressure, and a sub-joint portion having a joint strength lower than or equal to the main joint portion.
The sub-joining portion is disposed at a position closer to the electrode body unit accommodation space than the main joint portion, and the internal pressure of the electrode body unit housing space during normal use is applied to the sub-joint portion and the sub-joint portion The main joint and the sub-joint are formed at a position where the internal pressure is applied to the main joint when the pressure is released; and a substantial joint strength is provided between the main joint and the sub-joint. Disjoint non-joints are formed;
A power storage device is provided. At least a part of the outer edge of the exterior body constitutes a sealed flange portion made of an overlaid exterior film,
The joint valve part forms a part of the flange part, and is formed integrally with the surrounding flange part by the superposed outer film so as to have a joint strength lower than the joint strength of the surrounding flange part. The power storage device according to claim 1 or 2. Comprising a frame that holds at least the outer edge of the exterior body,
The power storage device according to claim 1, wherein the joint valve portion is exposed to the outside without being shielded by the frame. Comprising a frame that holds at least the outer edge of the exterior body,
Here, the portion of the frame opposite to the joint valve portion is a notch portion that shields the joint valve portion and forms a gap between the joint valve portion and the frame body, and the pressure rise The electrical storage device according to any one of claims 1 to 3, wherein a cutout portion that sometimes allows the adhesive portion to be opened is formed continuously from the peripheral end to the outer peripheral end of the frame in the opposing portion. . A film exterior power storage device comprising: an electrode body unit having a positive electrode and a negative electrode; a film exterior body in which a space for accommodating the electrode body unit is formed; and a frame body that holds at least an outer edge of the exterior body. The internal pressure release mechanism with the following configuration:
In a part of the sealed outer edge of the exterior body, a joint valve portion formed by adhesion of the overlaid films, and when the internal pressure of the electrode body unit accommodation space of the exterior body rises to a predetermined pressure A bonding valve portion that opens at least a part of the bonding portion and communicates the inside and outside of the exterior body; and wherein the portion of the frame facing the bonding valve portion is shielded from the bonding valve portion. However, a notch part that forms a gap between the joint valve part and the frame body, and the notch part that allows the adhesive part to be opened when the pressure rises is formed in the frame body at the opposite part. Formed continuously from the peripheral edge to the outer peripheral edge;
A power storage device is provided.   The opening portion of the opening to the outer peripheral end of the gap in the gap is larger than the opening area of the opening to the peripheral end of the frame in the gap formed between the notch portion and the joint valve portion. It is small and formed so that there is no corner portion protruding at an angle of a right angle or less on the inner surface facing the joint valve portion of the notch portion extending from the peripheral edge of the frame body to the outer peripheral edge of the frame body. Item 7. The power storage device according to Item 5 or 6.   8. The power storage device according to claim 7, wherein an inner surface of the cutout portion extending from the peripheral edge of the frame body to the outer peripheral edge of the frame body is formed with a gently curved surface.   The joining valve portion is a welding portion formed at a position close to the electrode body unit accommodation space, and is opened when the internal pressure of the electrode body unit accommodation space rises to a predetermined pressure. 9. An opening passage formed in advance between the formed films, wherein one end is in contact with the welded portion and the other end is opened at the outer end of the film exterior body. The power storage device described. A power storage device having a frame sandwiching an outer edge where films overlap each other and containing an electrode body unit inside a film outer package,
A power storage device, wherein a thin portion that is depressed toward a surface sandwiching an outer edge is formed in a part of the frame so as to be continuous from an inner peripheral end to an outer peripheral end of the frame.   The power storage device according to claim 10, wherein the thin portion is an arch-shaped depression that curves toward a surface sandwiching an outer edge. It is a frame that holds a film exterior type power storage device having a flange portion around which films overlap,
On the other inner peripheral side of the frame, a groove portion is formed to sandwich the flange,
A frame body characterized in that at least a part of the groove is closed on the outer peripheral side. The film exterior power storage device has a corner portion and a straight portion in the outline of the flange portion,
The frame body is configured by joining a plurality of frame members,
The frame according to claim 12, wherein a joint portion for joining individual frame members is joined at the straight portion. The frame according to claim 13, wherein the plurality of frame members are mechanically joined by engagement members.

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