Method of manufacturing a laminated power storage element

A laminated power storage element includes: an exterior body shaped into a flat bag shape by laminating a pair of laminated films to weld a peripheral edge region; an electrode body sealed within the exterior body; a positive and a negative electrode terminal portion allowed to project outside the exterior body from a predetermined margin of the exterior body; and a pair of tab films welded on surfaces where the pair of laminated films oppose one another in a region along the predetermined margin to mutually weld the pair of laminated films, and the tab film covers an end surface of the laminated film while deviating outward from the exterior body from the predetermined margin, and covers both front and back surfaces of each of a base end of the positive electrode terminal portion and a base end of the negative electrode terminal portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2016-137458 filed on Jul. 12, 2016, Japanese Patent Application No. 2016-248005 filed on Dec. 21, 2016, and Japanese Patent Application No. 2017-003509 filed on Jan. 12, 2017, which are herein incorporated by reference.

BACKGROUND

Technical Field

The present disclosure relates to a laminate-type power storage element that houses a power generation element in an exterior body formed of laminated films and a method of manufacturing the same.

Related Art

A laminate-type power storage element houses a flat plate-shaped electrode body including a sheet-shaped positive electrode and a negative electrode in a flat-bag-shaped exterior body formed of laminated films. The laminate-type power storage element, which is appropriate for downsizing and thinning, is used as a power supply for an extremely thin electronic device (hereinafter, a thin electronic device) or similar device that incorporates a power supply, such as an IC card with a one-time password function and a display, an IC card with display, a tag, and a token (one-time password generator).

FIG. 1AandFIG. 1Billustrate an exemplary laminate-type power storage element101. The laminate-type power storage element101exemplified inFIG. 1AandFIG. 1Bis a lithium primary battery using a nonaqueous electrolyte.FIG. 1Ais an external view of the laminate-type power storage element101.FIG. 1Bis an exploded perspective view illustrating an exemplary internal structure of the laminate-type power storage element101.

As illustrated inFIG. 1A, the laminate-type power storage element101has a flat plate-shaped appearance. An exterior body11formed of laminated films11aand11bshaped into a flat rectangular bag internally seals a power generating element. In the laminate-type power storage element101illustrated inFIG. 1AandFIG. 1B, a positive electrode terminal plate23and a negative electrode terminal plate33are guided to outside from a predetermined margin13(hereinafter referred to as a terminal lead margin13) of the rectangular exterior body11.

Next, the following describes a structure of the laminate-type power storage element101with reference toFIG. 1B.FIG. 1Bhatches some members and sites for easy distinction from other members and sites. As illustrated inFIG. 1B, the exterior body11internally seals an electrode body10together with electrolyte. The electrode body10is formed by laminating a sheet-shaped positive electrode20and a sheet-shaped negative electrode30via a separator40.

The positive electrode20is formed by disposing a positive electrode material22containing a positive-electrode active material over one principal surface of a positive electrode current collector21made of a metal plate or a metal foil. The negative electrode30is formed by disposing a negative electrode material32containing a negative-electrode active material over one principal surface of a negative electrode current collector31made of a metal plate, a metal foil, or a similar material. The electrode body10is configured by laminating and press-bonding the positive electrode20and the negative electrode30such that the positive electrode material22and the negative electrode material32(hereinafter referred to as the electrode materials22and32as a whole) are opposed via the separator40.

The exterior body11is configured by welding peripheral edge regions12, which are hatched or indicated by the dotted line frame inFIG. 1B, of two rectangular aluminum laminated films (11aand11b), which are stacked to one another, by thermocompression bonding to seal the inside. As is well-known, the laminated films (11aand11b) have a structure where one or more resin layers are laminated on front and back of a metal foil (aluminum foil, stainless steel foil) serving as a base material. Furthermore, generally, the laminated films (11aand11b) have a structure where a protecting layer made of, for example, a polyamide resin is laminated on a front surface, which will be an outer surface of the exterior body11, and an adhesive layer with thermal weldability made of, for example, a polypropylene is laminated on a back surface, which will be an inner surface of the exterior body11.

The positive electrode current collector21on which the positive electrode material22is laminated is electrically coupled to the positive electrode terminal plate23. The negative electrode current collector31on which the negative electrode material32is laminated is electrically coupled to the negative electrode terminal plate33. Then, the positive electrode terminal plate23and the negative electrode terminal plate33(hereinafter referred to as the electrode terminal plates (23and33) as a whole) are guided outside of the exterior body11, which is in a sealing state.

Therefore, at a part to which the electrode terminal plates (23and33) are guided at the terminal lead margin13of the exterior body11, the adhesive layers of the laminated films (11aand11b) are not welded to one another. Thus, an adhesive strength between the electrode terminal plates (23and33) and the laminated films (11aand11b) are possibly not sufficiently ensured.

At the terminal lead margin13, it is difficult to interpose the adhesive layers in a melted state over a thickness direction of the electrode terminal plates (23and33). Thus, this terminal lead margin13is possibly not sufficiently sealed to reduce a waterproof performance.

Therefore, the laminate-type power storage element101has a structure for surely sealing the terminal lead margin13of the exterior body11. A sealing method of the terminal lead margin13includes a method using tab leads50as the electrode terminal plates (23and33) and a method that mounts strip-shaped metal foils or metal plates (hereinafter referred to as terminal leads51) to the positive electrode current collector21and the negative electrode current collector31(hereinafter referred to as the electrode current collectors (21and31) as a whole) to use these terminal leads51directly as the electrode terminal plates (23and33).

FIG. 1Billustrates the method using the tab leads50. The electrode terminal plates (23and33) constituted of the tab leads50are coupled to the positive electrode current collector21and the negative electrode current collector31respectively. The tab lead50, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2008-192451, has a structure where a sealing material (hereinafter, a tab film52) made of insulating resin is bonded on an extension of the strip-shaped terminal lead51made of a metal plate or a metal foil that is substantively the electrode terminal plate (23or33) so as to sandwich this terminal lead51.

The terminal leads51each have one end portion53exposed to outside of the exterior body11, and the other end portion coupled to parts of the positive electrode current collector21and the negative electrode current collector31by a method such as ultrasonic welding. Needless to say, separate strip-shaped metal plates or metal foils may be mounted to the positive electrode current collector21and the negative electrode current collector31to further couple the tab leads50to these metal plates or metal foils. Then, when the flat-bag-shaped exterior body11is formed by thermocompression-bonding the peripheral edge regions12of the laminated films (11aand11b) opposed to one another, the tab films52of the tab leads50are thermally welded with the laminated films (11aand11b) at the terminal lead margin13of the peripheral edge region12of the exterior body11. Accordingly, at this terminal lead margin13, the tab films52welded to the terminal leads51are welded to the adhesive layers of the laminated films (11aand11b).

On the other hand, the method using the terminal leads51directly as the electrode terminal plates (23and33) without the tab leads50further includes a method that mounts separate terminal leads51to the positive electrode current collector21and the negative electrode current collector31, and a method that integratedly forms strip-shaped convex portions corresponding to the terminal leads51on the respective positive electrode current collector21and negative electrode current collector31to take these convex portions as the electrode terminal plates (23and33).

FIG. 2AandFIG. 2Billustrate exploded perspective views of laminate-type power storage elements (102and103) that employ a method without the tab leads50.FIG. 2Aillustrates the laminate-type power storage element102corresponding to the method that mounts the electrode terminal plates (23and33) as the separate terminal leads51to the positive electrode current collector21and the negative electrode current collector31.

FIG. 2Billustrates the laminate-type power storage element103that disposes convex portions (24and34) that double as the electrode terminal plates (23and33) on the positive electrode current collector21and the negative electrode current collector31. Then, as illustrated inFIG. 2AandFIG. 2B, the laminate-type power storage elements (102and103), which have employed the method without the tab leads50, employ a method that seals the terminal lead margin13using strip-shaped tab films (14aand14b) instead of the tab leads50.

Then, in this method, in the peripheral edge region12of the exterior body11, the strip-shaped tab films (14aand14b) are bonded to the terminal lead margin13by thermocompression bonding, in a state where the strip-shaped tab films (14aand14b) are preliminarily welded to the back surfaces of the laminated films (11aand11b). Then, the exterior body11is shaped by thermocompression-bonding the peripheral edge regions12of the laminated films (11aand11b).

That is, for the laminated films (11aand11b) opposed to one another, the laminated films (11aand11b) are bonded to one another via these strip-shaped tab films (14aand14b) at the terminal lead margin13.

As described above, the laminate-type power storage elements101,102, and103have the structure where the electrode terminal plates (23and33) are guided from the flat bag-shaped exterior body11by thermocompression-bonding the opposed laminated films (11aand11b) one another. Then, the method that seals the terminal lead margin13of the exterior body11basically includes the method using the tab leads50(hereinafter referred to as a tab lead method) and the method using the strip-shaped tab films (14aand14b) (hereinafter referred to as a tab film method).

In the current situation, the tab lead method is a mainstream. However, in this method, the terminal leads51of the tab leads50are welded to the electrode current collectors (21and31) by ultrasonic welding, thus increasing man-hours in assembling the laminate-type power storage element101, and an expensive ultrasonic welding machine is also required, thus increasing a production cost of the laminate-type power storage element101.

Furthermore, the tab lead50, which is a required member, is a member sold as an industrial product manufactured separately from the laminate-type power storage element101, thus also increasing a member cost in the tab lead method compared with the tab film method.

On the other hand, the tab film method does not require the tab lead50, which is an expensive member, and is also applicable to the electrode body10having a structure where the electrode terminal plates (23and33) and the electrode current collectors (21and31) are preliminarily integrated. Accordingly, the tab film method overwhelmingly has an advantage in price reduction and versatility compared with the tab lead method. Then, when the laminate-type power storage elements appropriate for downsizing and thinning are provided for use in, for example, IC cards provided in large amounts, and extremely inexpensively, and in some cases, charge-free, the price reduction is required as an extremely important matter for the laminate-type power storage element. Accordingly, it is expected that the tab-film-method laminate-type power storage element will be a mainstream in the future.

Then, when the inventor has examined reliability of the tab-film-method laminate-type power storage element, the inventor has found the reliability decreases caused by a structure of the laminated film. This will be described with reference toFIG. 3.

FIG. 3is a side view of the laminate-type power storage element102illustrated inFIG. 2Ain a state incorporated in a thin electronic device when being viewed from a thickness direction of the laminate-type power storage element102.

As illustrated inFIG. 3, when the laminate-type power storage element102is incorporated in the thin electronic device, regions projecting outside the exterior body11at the electrode terminal plates (23and33) (hereinafter referred to as electrode terminal portions (25and35)) are coupled to a circuit board100. At this time, for example, the electrode terminal portions (25and35) possibly bend into crank shapes. Then, when base ends (26and36) sides of the respective electrode terminal portions (25and35) of the positive electrode20and the negative electrode30bend taking the terminal lead margin13as a fulcrum, the electrode terminal plates (23and33) possibly contact the metal foils exposed on cutting surfaces11cof the laminated films (11aand11b) to short-circuit the positive electrode20and the negative electrode30. It is considered to prevent the short circuit by sticking an insulating tape (hereinafter referred to as a protective tape) that protects the cutting surfaces11cof the laminated films (11aand11b). However, this protective tape inhibits thinning of the laminate-type power storage element102, and also inhibits the cost reduction due to a member cost of the protective tape and a process addition for sticking the protective tape.

SUMMARY

A laminate-type power storage element according to one aspect to achieve the above-described object includes: an exterior body shaped into a flat bag shape by laminating a pair of laminated films to weld a peripheral edge region, the pair of laminated films being formed by forming insulating resin layers on both surfaces of a metal foil base material; an electrode body sealed within the exterior body, the electrode body being constituted by laminating a sheet-shaped positive electrode and a sheet-shaped negative electrode via a separator; a positive electrode terminal portion constituted by allowing a part of a flat plate-shaped positive electrode terminal plate coupled to the positive electrode to project outside the exterior body from a predetermined margin of the exterior body; a negative electrode terminal portion constituted by allowing a part of a flat plate-shaped negative electrode terminal plate coupled to the negative electrode to project outside the exterior body from the predetermined margin of the exterior body; and a pair of tab films welded on surfaces where the pair of laminated films oppose one another in a region along the predetermined margin in the peripheral edge region of the exterior body to mutually weld the pair of laminated films while sandwiching the positive electrode terminal plate and the negative electrode terminal plate, and the tab film is formed to cover an end surface of the laminated film while deviating outward from the exterior body from the predetermined margin at a part where the positive electrode terminal plate and the negative electrode terminal plate are guided outside the exterior body, and to cover both front and back surfaces of each of a base end of the positive electrode terminal portion and a base end of the negative electrode terminal portion.

Further, a laminate-type power storage element may have an aspect where the laminate-type power storage element includes: an exterior body shaped into a flat bag shape by laminating a pair of laminated films to weld a peripheral edge region, the pair of laminated films being formed by forming insulating resin layers on both surfaces of a metal foil base material; an electrode body sealed within the exterior body, the electrode body being constituted by laminating a sheet-shaped positive electrode and a sheet-shaped negative electrode via a separator; a strip-shaped positive electrode terminal plate coupled to the positive electrode and allowed to project outside the exterior body from one side of the exterior body; a strip-shaped negative electrode terminal plate coupled to the negative electrode and allowed to project outside the exterior body from the one side of the exterior body; and a pair of tab films welded on surfaces where the pair of laminated films oppose one another along the one side of the exterior body to mutually weld the pair of laminated films while sandwiching the positive electrode terminal plate and the negative electrode terminal plate, and at least one of the pair of laminated films is formed into a shape such that at least a region where the tab films sandwich the positive electrode terminal plate and the negative electrode terminal plate is exposed.

Further, a method of manufacturing a laminate-type power storage element according to one aspect to achieve the above-described object includes: a tab film disposing step of disposing a tab film along a predetermined margin of a laminated film formed by forming insulating resin layers on both surfaces of a metal foil base material; an exterior body sealing step of disposing a pair of the laminated films so as to allow the respective tab films to oppose one another, sandwiching an electrode body between the pair of laminated films, the electrode body being constituted by laminating a sheet-shaped positive electrode coupled to a flat plate-shaped positive electrode terminal plate and a sheet-shaped negative electrode coupled to a flat plate-shaped negative electrode terminal plate via a separator, and performing thermocompression bonding on peripheral edge regions of the pair of laminated films in a state where the positive electrode terminal plate and the negative electrode terminal plate are allowed to project outside from the predetermined margin to seal the exterior body; and a tab film deforming step of selectively performing the thermocompression bonding on a part on which the positive electrode terminal plate and the negative electrode terminal plate are positioned in the peripheral edge regions of the pair of laminated films, deviating the tab film outward from the exterior body, covering an end surface of the laminated film with the tab film, and covering both front and back surfaces of respective base end portions of a positive electrode terminal portion and a negative electrode terminal portion with the tab films, the positive electrode terminal portion being a part allowed to project outside the exterior body in the positive electrode terminal plate, the negative electrode terminal portion being a part allowed to project outside the exterior body in the negative electrode terminal plate.

DETAILED DESCRIPTION OF THE INVENTION

The following describes working examples of the present disclosure with reference to the attached drawings. Like reference numerals designate corresponding or identical elements in the drawings used for the following description, and therefore such elements may not be further elaborated. While a reference numeral is assigned to a part in a drawing, if unnecessary, the reference numeral may not be assigned to the corresponding part in another drawing.

Process of Arriving at this Embodiment

As described above, in the laminate-type power storage element102, cross-sectional surfaces of the metal foils of the laminated films (11aand11b) are exposed at the terminal lead margin13of the exterior body11. The electrode terminal plates (23and33) possibly contact these cutting surfaces11cto cause the short circuit to occur. Thus, it is difficult to solve this occurrence of the short circuit while especially ensuring the thinning and the cost reduction at the same time. Accordingly, the inventor considered that if the strip-shaped tab films (14aand14b) used for sealing the terminal lead margin13have charge of a function similar to that of the protective tape, since the electrode terminal portions (25and35) do not directly contact the cutting surfaces11cof the laminated films (11aand11b), the short circuit did not occur, additional members such as the protective tape are not required, and the thickness can also be made equal to that of the conventional laminate-type power storage element.

FIG. 4Aillustrates a laminate-type power storage element104using the strip-shaped tab films (14aand14b) also as the protective tapes.FIG. 4Billustrates a laminate-type power storage element105using strip-shaped tab films114also as the protective tapes.

In the laminate-type power storage element104illustrated inFIG. 4A, the tab films (14aand14b) are projected only by a predetermined width w from the terminal lead margin13. Accordingly, even if the electrode terminal plates (23and33) bend, the tab films (14aand14b) can cover the cutting surfaces11cof the laminated films (11aand11b) to prevent the short circuit.

In the laminate-type power storage element105illustrated inFIG. 4B, as illustrated inFIG. 4C, the tab films114are used on which convex portions115along lead shapes of the electrode terminal plates (23and33) are disposed, and only these convex portions115project from the terminal lead margin13to cover the base ends (26and36) of the electrode terminal portions (25and35).

However, when the two kinds of laminate-type power storage elements (104and105) illustrated inFIG. 4AandFIG. 4Bwere actually prototyped, both of laminate-type power storage elements (104and105) required improvement.

First, in the laminate-type power storage element104illustrated inFIG. 4A, it is difficult to accurately form the peripheral edge regions12in a sealing process where the thermocompression bonding is performed on the peripheral edge regions12of the laminated films (11aand11b) to seal an inside of the exterior body11. Specifically, in the sealing process, the two laminated films (11aand11b) are required to be laminated one another in a state where the two laminated films (11aand11b) are accurately positioned. Then, when the peripheral edge regions12are formed by the thermocompression bonding, it is necessary not to break the electrode body by contact of a thermocompression bonding jig with a housing region of the electrode body10.

Accordingly, in the sealing process, as illustrated inFIG. 5, by using a jig that surrounds outer shapes of the rectangular laminated films (11aand11b) (hereinafter referred to as a positioning jig200), positioning is performed based on the outer shapes of the laminated films (11aand11b). This positioning jig200has a simple structure, but if only dimension accuracies of the laminated films (11aand11b) are ensured, extremely accurate positioning can be performed extremely easily. Therefore, in order to manufacture the laminate-type power storage element104at lower cost, the positioning jig200is desirably used.

However, as in the laminate-type power storage element104illustrated inFIG. 4A, if the tab films (14aand14b) are projected from the terminal lead margin13by the uniform width w, these projected tab films (14aand14b) prevent positioning using the outer shapes of the laminated films (11aand11b). It is also considered to improve a shape and a size of the positioning jig200in consideration of the projection width w of the tab film14. However, the tab films (14aand14b) are strip-shaped films constituted of a three-layer structure where taking a film made of resin such as polyethylene naphthalate (PEN) as a substrate body, adhesive layers made of thermoplastic resin (for example, modified polypropylene such as PPa) are formed on both front and back surfaces of this substrate body, or a single-layered adhesive layer without the substrate body. When the terminal lead margin13is sealed, regions of the tab films (14aand14b) projected from the exterior body11dissolve to deform, thus causing a possibility of deviation of the position during the sealing process. It is also considered to seal three sides except for the terminal lead margin13to finally seal the terminal lead margin13. However, as illustrated inFIG. 6, if margins113of the tab films (14aand14b) are abutted on the positioning jig200for positioning, as illustrated within circular frames201inFIG. 6, the tab films (14aand14b) themselves easily deform. Thus, a positioning accuracy is not ensured. That is, it is difficult to take the outer shapes of the tab films (14aand14b) as positioning bases.

Meanwhile, as illustrated inFIG. 4B, in the method using the tab films114on which the convex portions115along the lead shapes of the electrode terminal plates (23and33) are disposed, only the convex portions115of the tab films114project from the terminal lead margin13. Accordingly, positioning can be performed by the outer shapes of the laminated films (11aand11b) also using the positioning jig200illustrated inFIG. 5.

However, as a process before the two laminated films (11aand11b) are stacked, a process where the convex portions115are precisely matched to the lead positions of the electrode terminal plates (23and33) is required, thus increasing the production cost. The tab films114on which the convex portions115are disposed are specially prepared differently from the strip-shaped tab films (14aand14b). These tab films114including the convex portions115will be a factor that increases the member cost.

Accordingly, it is preferred not to use the special-shaped tab films114and to ensure positioning based on the outer shapes of the laminated films (11aand11b) in the sealing process. Needless to say, even if this structure is employed, it is also necessary that this structure is a structure that can maintain thinness equal to or more than that of a conventional structure without cost increase. Then, the inventor seriously studied the structure of a laminate-type power storage element that can react to these requests, thus arriving at the present embodiment.

First Embodiment

Embodiment

FIG. 7AandFIG. 7Billustrate a laminate-type power storage element1(hereinafter referred to as a power storage element1) according to one embodiment of the present disclosure.FIG. 7Ais a perspective view illustrating an appearance of the power storage element1.FIG. 7Bis an exploded perspective view of the power storage element1.

In the following description, as illustrated inFIG. 7AandFIG. 7B, in the power storage element1, a laminating direction of the two laminated films (11aand11b) and power generating elements (the positive electrode20, the negative electrode30, and the separator40) in the electrode body10is an up-down direction, and a projecting direction of the electrode terminal plates (23and33) is a front-rear direction. A direction perpendicular to each of the up-down and front-rear directions is a right-left direction. Then, takingFIG. 7Aas a perspective view viewed from the upper right and the front, the respective up-down, right-left, and front-rear directions are specified.

Then, as illustrated inFIG. 7AandFIG. 7B, in the power storage element1according to the present embodiment, parts14con extensions of the tab films (14aand14b) that are normally strip-shaped that extend right and left deform forward. Then, these deformed regions (hereinafter referred to as deformation portions14c) cover both upper and lower surfaces of the base ends (26and36) of the electrode terminal portions (25and35) while deviating outward from the exterior body11.

FIG. 7Billustrates the upper and lower two tab films (14aand14b) individually. However, in practice, the two tab films (14aand14b) are welded to one another while sandwiching the positive and negative electrode terminal plates (23and33).

Then, in the power storage element1according to the embodiment, the deformation portions14cprevent the short circuit by the action similar to that of the tab films114on which the convex portions115are selectively disposed illustrated inFIG. 4Bon ahead. At the tab films (14aand14b), regions except for the deformation portions14cdo not project outside the exterior body11, thus ensuring maintenance of the positioning accuracy when the two laminated films (11aand11b) are laminated in the sealing process.

Further, even if bending stress is applied in a direction opposite to the lead direction of the electrode terminal plates (23and33), the base ends (26and36) of the electrode terminal portions (25and35) are covered with the deformation portions14cmade of resin. Thus, the electrode terminal plates (23and33) do not bend at an acute angle taking the terminal lead margin13as the fulcrum. Therefore, this can prevent break of the electrode terminal plates (23and33) taking the terminal lead margin13as an edge.

Method of Manufacturing Power Storage Element1

Next, the following describes a method of manufacturing the power storage element1according to the above-described embodiment. Schematically, after the power storage element102illustrated inFIG. 2Ais manufactured, the deformation portions14cin the power storage element1according to the embodiment of the present disclosure illustrated inFIG. 7AandFIG. 7Bare famed. In the power storage element1according to the embodiment manufactured here, the electrode body10has a configuration similar to that of a thin manganese dioxide lithium primary battery described in above-described Non-Patent Literature, and the exterior body11has outside dimensions whose vertical length is 22 mm, lateral width is 27 mm, and thickness in the housing region of the electrode body10is 0.45 mm.

FIG. 8AtoFIG. 8Hillustrate the method of manufacturing the power storage element1according to the present embodiment.FIG. 8AtoFIG. 8Hillustrate respective processes in this method of manufacturing in order. In the respective processes, at least in the processes illustrated inFIG. 8AtoFIG. 8G, the above-described positioning jig200is used. The respective up-down, front-rear, and right-left directions inFIG. 8AtoFIG. 8Hare directions specified with respect to the power storage element1in an assembled state. When the positioning jig200is placed on a horizontal surface, a direction that the backside surfaces of the laminated films (11aand11b) mounted on the positioning jig200face is vertically upward or vertically downward, and this direction differs depending on the process.

First, as illustrated inFIG. 8A, the tab film14ais welded to the terminal lead margin13of the laminated film11aafter positioning. Here, a three-layers type tab film14ataking a PEN film as the substrate body and having front and back surfaces on which PPa adhesive layers are formed is used. In a state where this tab film14ais disposed in a vertical direction on the laminated film11a, the thermocompression bonding is performed, for example, in a condition where the temperature is 100° C., the period is one second, and the pressure is 0.2 MPa.

As illustrated inFIG. 8B, the tab film14bis welded to the terminal lead margin13of the laminated film11bafter positioning. Here, a three-layers type tab film14btaking a PEN film as the substrate body and having front and back surfaces on which PPa adhesive layers are formed is used. In a state where this tab film14bis disposed in a vertical direction on the laminated film11b, the thermocompression bonding is performed, for example, in a condition where the temperature is 100° C., the period is one second, and the pressure is 0.2 MPa.

Then, as illustrated inFIG. 8C, the positive electrode20, which has already been assembled, is laminated on a top surface of the lower (the positive electrode20side) laminated film11a, and a distal end side of the positive electrode terminal plate23is projected outward from the tab film14ato make this projecting region the electrode terminal portion25of the positive electrode20. Then, the thermocompression bonding is performed on a laminated region of the tab film14aand the positive electrode terminal plate23to weld the positive electrode terminal plate23and the tab film14a.

For the upper (the negative electrode30side) laminated film11b, as illustrated inFIG. 8D, the negative electrode30, which has already been assembled, is laminated below the negative electrode30side laminated film11b, and a distal end side of the negative electrode terminal plate33is projected outward from the tab film14bto make this projecting region the electrode terminal portion35of the negative electrode30. Then, the thermocompression bonding is performed on a laminated region of the negative electrode terminal plate33and the laminated film11bto weld the tab film14bto the negative electrode terminal plate33. This completes an assembled component at the negative electrode30side.

Next, as illustrated inFIG. 8E, the separator40is disposed on a top surface of the positive electrode20to complete an assembled component at the positive electrode20side. Then, as illustrated inFIG. 8F, the assembled components at the positive electrode20side and the negative electrode30side are laminated using the positioning jig200, and further, at the peripheral edge regions12of the rectangular laminated films (11aand11b) opposed to one another, the thermocompression bonding is performed on three margins (13and15) sides including the terminal lead margin13, for example, in a condition with 150° C., one second, and 0.2 MPa. These mutually shape the bag-shaped exterior body11having an opening17at one side16. Then, the electrolyte is injected into the bag-shaped exterior body11from this opening17, and the thermocompression bonding is performed on the margin16side at which this opening17presents at the peripheral edge region12to seal the exterior body11. This first completes the power storage element102illustrated inFIG. 2A.

As described above, after the power storage element102is completed, this power storage element102is taken out from the positioning jig200, and as illustrated inFIG. 8G, at the sealing region of the exterior body11, the thermocompression bonding is again performed, selectively in a predetermined condition (for example, 100° C., one second, and 0.2 MPa), on regions202to which the electrode terminal plates (23and33) are guided at the terminal lead margin13side, and then a part of the adhesive layers of the tab films (14aand14b) on which the thermocompression bonding has been performed into strip shapes is eluted outward from the exterior body11. Then, if the adhesive layers harden in the eluted shape, as illustrated inFIG. 8H, the power storage element1according to the present embodiment is completed.

In a procedure for manufacturing the power storage element1according to the embodiment illustrated inFIG. 8AtoFIG. 8H, the procedure inFIG. 8AtoFIG. 8G, that is, the procedure for manufacturing the power storage element102is not limited to the above-described working example. The following procedure is conceivable. For example, first, the electrode body10is assembled, and the tab films (14aand14b) are disposed along the terminal lead margins13of the respective laminated films (11aand11b) at the positive electrode20side and the negative electrode30side. Then, the electrode body10, which has been already assembled, is disposed between the laminated film11aand the laminated film11b, and then, the thermocompression bonding is performed on the peripheral edge regions12of the laminated films (11aand11b).

Needless to say, the power storage element1in the embodiment may be created by creating the power storage element103illustrated inFIG. 2Bto perform a process similar to the process illustrated inFIG. 8Gon this power storage element103. In any case, in the process beforeFIG. 8H, it is only necessary to manufacture a power storage element having a sealing structure in the tab film method.

Reliability Test

Next, taking the power storage element1according to the embodiment manufactured in the procedure inFIG. 8AtoFIG. 8Hand the power storage element102obtained in this manufacturing process as samples, for each sample, 30 pieces of individuals were manufactured. Then, the following test was performed. The electrode terminal plates (23and33) of the positive electrodes20and the negative electrodes30of all the individuals were bent at an angle of 90° upward (or downward) at parts of the base ends (26and36) of the electrode terminal portions (25and35). Then, an occurrence status of the short circuit between the positive electrode terminal plates23and the negative electrode terminal plates33was examined.

As a result, in the sample of the power storage element1in the embodiment, among the 30 pieces of individuals, the short circuit never occurred at any individual. Meanwhile, in the sample of the power storage element102, the short circuits occurred at 28 pieces of individuals.

As described above, it has been confirmed that the power storage element1surely prevents the short circuit due to the contact between the metal foils exposed on the cutting surfaces11cof the laminated films (11aand11b) and the electrode terminal portions (25and35) and has a high reliability.

Other Working Examples

The power storage element1according to the first embodiment of the present disclosure is applicable to various kinds of storage elements (for example, a lithium secondary battery and an electric double layer capacitor), not limited to the lithium primary battery, insofar as the power storage element1has a structure that seals the flat plate-shaped electrode body10into the exterior body11constituted of the laminated films (11aand11b).

The power storage element1according to the first embodiment may be a single-layer type including one each of the sheet-shaped positive electrode20and negative electrode30, or may be a multilayer type including the electrode bodies10for a plurality of layers.

The single-layer type power storage element1has a basic structure to achieve thinning by including only the smallest number of electrode bodies10. Then, the power storage element1according to the present embodiment has a structure where the deformation portions14care formed on the tab films (14aand14b) to set out thinning.

Therefore, when the power storage element1according to the present embodiment is the single-layer type, a combined effect of the structure of the single-layer type power storage element1and the structure using the tab films (14aand14b) on which the deformation portions14care formed can make the effect of the thinning immeasurable.

Needless to say, even for the multilayer type power storage element1, the cost reduction can be expected by eliminating the need of the protective tapes that insulate the cutting surfaces11cof the laminated films (11aand11b) and the sticking process of these protective tapes.

In the method of manufacturing the power storage element1according to the first embodiment, the terminal lead margin13of the exterior body11is sealed via the strip-shaped tab films (14aand14b), and followed by this sealing process, the thermocompression bonding is again performed on the parts202in the peripheral edge region12at the terminal lead margin13side to form the deformation portions14c.

However, depending on a type and a size of an electronic device where the power storage element1is incorporated, the presence/absence of the deformation portions14cis possibly not asked. In such case, the formation process of the deformation portions14cis not continuously performed after the sealing process, and may be performed immediately before the shipping of the power storage element1or immediately before the power storage element1is incorporated in the electronic device. This can save the cost required for stock control.

If a thermocompression bonding jig that can change the temperature and the pressure depending on the regions202on which the deformation portions14care formed and the other region12is used, the deformation portions14ccan be simultaneously formed in the process that seals the terminal lead margin13.

When the deformation portions14care formed, while it is possible to reduce the man-hour and a manufacturing period, which contributes to the cost reduction, a special thermocompression bonding jig that leads to the cost increase is necessary. However, when the deformation portions14care formed after the sealing process, the existing thermocompression bonding jig can be used in the sealing process. This is flexibly applicable to various usages of the power storage element1. It is also possible to manufacture conventional storage elements and the power storage elements1according to the present embodiment in the mix in an identical manufacturing line.

The outer shape of the exterior body11is preferred to be a rectangular, or at least to have a straight terminal lead margin13, in that general-purpose strip-shaped tab films (14aand14b) can be used. However, if the base ends (26and36) of the electrode terminal portions (25and35) are covered with the tab films (14aand14b) deviated to the outside of the exterior body11, the exterior body11is not necessarily to have these shapes, and for example, may have an appropriate shape such as a circular or polygonal planar shape.

In the power storage element1according to the above-described embodiment, the positive electrode terminal plate23and the negative electrode terminal plate33are guided from the exterior body11in the identical direction. However, the positive electrode terminal plate23and the negative electrode terminal plate33may be guided in opposite directions from two margins13opposed to one another at the exterior body11. Needless to say, the electrode terminal plates (23and33) may be guided in directions that intersect with one another, such as two margins13adjacent to one another on the rectangular planar surface.

Second Embodiment

Embodiment

FIG. 9AtoFIG. 9Cillustrate a laminate-type power storage element1aaccording to a second embodiment of the present disclosure.FIG. 9Ais an exploded perspective view of the laminate-type power storage element1a.FIG. 9Bis a perspective view illustrating an appearance of the laminate-type power storage element1a.FIG. 9Cis an enlarged view of a part of a cross section viewed from an arrow a-a inFIG. 9B.

In the following description, as illustrated inFIG. 9AtoFIG. 9C, in the laminate-type power storage element1a, the thickness direction of the flat-bag-shaped exterior body11, that is, the laminating direction of the two laminated films (11aand11b) and the power generating elements (the positive electrode20, the negative electrode30, and the separator40) in the electrode body10is the up-down direction, and the projecting direction of the electrode terminal plates (23and33) is the front-rear direction. The direction perpendicular to each of the up-down and front-rear directions is the right-left direction. Then, in the following description, withFIG. 9AandFIG. 9Btaken as perspective views viewed from the upper right and the front, the respective up-down, right-left, and front-rear directions are specified.

In the laminate-type power storage element1aaccording to the present embodiment, as illustrated inFIG. 9A, right and left margins15bof the upper laminated film11band right and left margins15aof the lower laminated film11ahave different lengths. In the example illustrated inFIG. 9A, the right and left margins15aof the lower laminated film11aare longer than the right and left margins15bof the upper laminated film11bby a length D. Then, the upper and lower laminated films (11aand11b) are laminated with the right and left margins (15aand15b) and rearward margins (16aand16b) being aligned one another. Accordingly, a terminal lead margin13aof the lower laminated film11aprojects ahead with respect to a terminal lead margin13bof the upper laminated film11b.

The two strip-shaped tab films (14aand14b) have identical shapes, and sandwich the respective electrode terminal plates (23and33) of the positive electrode20and the negative electrode30together in a state where the two strip-shaped tab films (14aand14b) have outer shapes aligned with one another. At the two tab films (14aand14b), the front margins113are aligned with the terminal lead margin13aof the lower laminated film11a, rear end sides are interposed between the two laminated films (11aand11b). Accordingly, if the peripheral edge regions12of the two laminated films (11aand11b) are welded, as illustrated inFIG. 9B, a top surface14uof the tab film14is exposed in a strip-shaped region having a front-to-rear width D that projects ahead of the terminal lead margin13bof the upper laminated film11b. Then, in the laminate-type power storage element1aaccording to the second embodiment, as illustrated inFIG. 9C, in a region between the terminal lead margins (13aand13b) of the two laminated films (11aand11b), top surfaces of the electrode terminal plates (23and33) will be covered with the tab film14. Therefore, the electrode terminal portions (25and35) do not contact the cutting surfaces11cof the laminated films (11aand11b), insofar as the electrode terminal portions (25and35) are folded on the upper side.

In the laminate-type power storage element1aaccording to the present embodiment, if the electrode terminal portions (25and35) are bent downward, the electrode terminal plates (23and33) contact the metal foil exposed on the cutting surface11cof the lower laminated film11a, and thus there is a possibility that the short circuit may occur. However, such short circuit is likely to occur when the laminate-type power storage element1ais incorporated in the thin electronic device as also illustrated inFIG. 3. That is, when the laminate-type power storage element1ais incorporated in the thin electronic device, if only directions of a top surface and a lower surface of the laminate-type power storage element1aare not incorrect, the short circuit is less likely to occur.

Then, in the laminate-type power storage element1aaccording to the present embodiment, the tab film14is exposed in a direction to which the electrode terminal plates (23and33) may be bent, thus facilitating confirmation of correct directions of the top surface and the lower surface when the laminate-type power storage element1ais incorporated in the electronic device.

In the laminate-type power storage element1aaccording to the present embodiment, it is only necessary to change the sizes of the two laminated films (11aand11b) that constitute the exterior body11, and one laminated film11a(or11b) among the two laminated films (11aand11b) may be identical to that used for the laminate-type power storage elements1,102, and103. That is, the effect that can prevent the short circuit is sufficiently obtained almost without the cost increase.

In the laminate-type power storage element1aaccording to the present embodiment, the front margin113of the tab film14is aligned with the terminal lead margin13aof the lower laminated film11a, and the tab film14does not project outward with respect to a planar surface region of the exterior body11. Therefore, the positioning accuracy can be maintained when the two laminated films (11aand11b) are laminated in the sealing process, thus ensuring positioning based on the outer shape of the lower laminated film11aas illustrated inFIG. 5.

Needless to say, the base ends (26and36) at top surface sides of the electrode terminal portions (25and35) are covered with the tab film14made of resin. Thus, insofar as the electrode terminal plates (23and33) are bent on the upper side, the electrode terminal plates (23and33) are not bent at the acute angle taking the terminal lead margin13bof the upper laminated film11bas the fulcrum. That is, the laminate-type power storage element1aaccording to the present embodiment can prevent the break of the electrode terminal plates (23and33) taking the terminal lead margin13bas the edge.

In the laminate-type power storage element1aillustrated inFIG. 9AtoFIG. 9C, the upper laminated film11bprojects with respect to the lower laminated film11aover the entire length of the terminal lead margin13. However, it is only necessary that one upper or lower laminated film (11aor11b) projects with respect to the other laminated film (11bor11a) in the region to which the electrode terminal plates (23and33) in the exterior body11are guided.

For example, as in a laminate-type power storage element1billustrated inFIG. 10, the terminal lead margin13bof the upper laminated film11bmay be formed into a concave shape. In this laminate-type power storage element1b, a left edge and a right edge of the terminal lead margin13bat the upper laminated film11bare aligned with the straight terminal lead margin13aat the lower laminated film11a.

Reliability Test

Next, the laminate-type power storage element1aillustrated inFIG. 9AtoFIG. 9Cand the laminate-type power storage element102illustrated inFIG. 2Awere manufactured as the samples. Then, the following bending test was performed for each sample. The electrode terminal plates (23and33) of the positive electrode20and negative electrode30were bent upward at an angle of 90° at the parts of the base ends (26and36) of the electrode terminal portions (25and35). Thus, the presence/absence of the short circuit between the positive electrode terminal plate23and the negative electrode terminal plate33was examined. Here, for each sample, 30 pieces of individuals were manufactured. The bending test was performed for total 60 pieces of individuals. As a result, in the sample of the laminate-type power storage element1aaccording to the present embodiment, the short circuit did not occur in all the 30 pieces of individuals. On the other hand, in the sample of the laminate-type power storage element102, the short circuit occurred in 28 pieces of individuals.

As described above, it was confirmed that the laminate-type power storage element1aaccording to the present embodiment, without the protective tape, surely prevents the short circuit due to the contact between the metal foils exposed on the cutting surfaces11cof the laminated films (11aand11b) and the electrode terminal portions (25and35), and has the high reliability.

Other Working Examples

The laminate-type power storage elements (1aand1b) according to the second embodiment are “the single-layer type” that houses the electrode body10including one each of the sheet-shaped positive electrode20and negative electrode30in the exterior body11. However, the laminate-type power storage elements (1aand1b) may be “the multilayer type” including the electrode bodies10for a plurality of layers.

The single-layer type power storage elements1aand1beach have a basic structure to achieve thinning by including only the smallest number of electrode bodies10. Then, the laminate-type power storage elements1aand1baccording to the present embodiment each has a structure that can prevent the short circuit using the tab films (14aand14b) and without the protective tape, thus achieving further thinning with respect to the basic structure.

Needless to say, even for the laminate-type power storage elements1aand1bincluding the multilayer type electrode bodies10, the cost reduction can be expected by eliminating the need of the protective tapes that insulate the cutting surfaces11cof the laminated films (11aand11b) and the sticking process of these protective tapes.

In the laminate-type power storage elements (1aand1b) according to the present embodiment, the positive electrode terminal plate23and the negative electrode terminal plate33are guided from the exterior body11in the identical direction. However, the positive electrode terminal plate23and the negative electrode terminal plate33may be guided in opposite directions from two margins13opposed to one another at the exterior body11. Needless to say, the electrode terminal plates (23and33) may be guided in directions that intersect with one another, such as two margins13adjacent to one another on the rectangular planar surface.

In the laminate-type power storage elements (1aand1b) according to the second embodiment, the exterior body11having the rectangular-planar-shaped or straight terminal lead margin13is used in that the general-purpose strip-shaped tab film14can be used. However, it is not necessary that the outer shape of the exterior body11and the terminal lead margin13are rectangular or straight. The exterior body11may have an appropriate planar shape such as circular or polygonal. The terminal lead margin13may be a curved line.

In any case, it is only necessary that the electrode terminal plates (23and33) are guided from a predetermined region at the peripheral edge of the exterior body11, one (11aor11b) of the laminated films (11aand11b) opposed to one another projects with respect to the other (11bor11a) in this region, and the tab film14is disposed so as to be aligned with the outer shape of the one laminated film (11aor11b).

The laminate-type power storage elements1aand1baccording to the second embodiment are applicable to various kinds of storage elements (for example, a lithium secondary battery and an electric double layer capacitor), not limited to the lithium primary battery, insofar as the laminate-type power storage elements1aand1beach have a structure that seals the flat plate-shaped electrode body10into the flat-bag-shaped exterior body11constituted of the laminated films (11aand11b). Needless to say, the laminate-type power storage elements1aand1bare applicable to a power storage element where the electrolyte is immersed in a polymer, such as a polymer battery. The laminate-type power storage elements1aand1bare applicable to a power storage element without electrolyte itself, such as an all-solid battery.

FIG. 11illustrates a structure of a laminate-type power storage element1cusing an all-solid battery111. The all-solid battery111housed in the exterior body11has a structure where current collectors (131and121) constituted of the metal foils are formed on a top surface and a lower surface of a laminated electrode body110formed by sandwiching a sheet-shaped solid electrolyte (solid electrolyte layer)140between a sheet-shaped positive electrode (positive electrode layer)120and a sheet-shaped negative electrode (negative electrode layer)130.

The laminated electrode body110is an integral sintered body. A method of manufacturing the laminated electrode body110includes a method of sintering a formed body obtained by pressurizing raw material powder using a mold (hereinafter referred to as a compression molding method), a well-known method using a green sheet (hereinafter, a green sheet method), and similar method. In the compression molding method, powder positive electrode layer material including a positive-electrode active material and a solid electrolyte, which will be raw materials of the positive electrode layer120, powder solid electrolyte, which will be a raw material of the solid electrolyte layer140, and powder negative electrode layer material including a negative electrode active material and a solid electrolyte, which will be raw materials of the negative electrode layer130are sequentially filled in the mold with laminated shapes (sheet shapes). Next, the powder raw materials of the respective layers laminated into sheet shapes are pressurized in their laminating direction to obtain a formed body. The formed body is sintered. Accordingly, the laminated electrode body110constituted of the integrated sintered body is manufactured.

In the green sheet method, slurry positive electrode layer material including the positive-electrode active material and the solid electrolyte, slurry negative electrode layer material including the negative electrode active material and the solid electrolyte, and slurry solid electrolyte layer material including the solid electrolyte each are shaped into a sheet-shaped green sheet, and a laminated body formed by sandwiching the green sheet of the solid electrolyte layer material between the green sheets of the positive electrode layer material and the negative electrode layer material is sintered to manufacture the laminated electrode body110.

Then, the all-solid battery111is completed by applying silver paste or by evaporating gold or the like over the top surface and the lower surface of the manufactured laminated electrode body110to form the current collectors (121and131).

Then, when this all-solid battery111is housed in the exterior body11constituted of the laminated films (11aand11b), it is only necessary to mount the strip-shaped electrode terminal plates (23and33) to the current collectors (121and131) to guide these electrode terminal plates (23and33) outward from the exterior body11.

Third Embodiment

Embodiment

FIG. 12AtoFIG. 12Cillustrate a laminate-type power storage element1daccording to a third embodiment of the present disclosure.FIG. 12Ais an exploded perspective view of the laminate-type power storage element1d.FIG. 12Bis a perspective view illustrating an appearance of the laminate-type power storage element1d.FIG. 12Cis an enlarged view of a part of a cross section viewed from an arrow a-a inFIG. 12B.

In the following description, as illustrated inFIG. 12AtoFIG. 12C, in the laminate-type power storage element1d, the thickness direction of the flat-bag-shaped exterior body11, that is, the laminating direction of the two laminated films (11aand11b) and the power generating elements (the positive electrode20, the negative electrode30, and the separator40) in the electrode body10is the up-down direction, and the projecting direction of the electrode terminal plates (23and33) is the front-rear direction. The direction perpendicular to each of the up-down, and front-rear directions is the right-left direction. Then, in the following, withFIG. 12AandFIG. 12Btaken as perspective views viewed from the upper right and the front, the respective up-down, right-left, and front-rear directions are specified.

As illustrated inFIG. 12A, at the terminal lead margins (13aand13b) of the two laminated films (11aand11b) that constitute the laminate-type power storage element1daccording to the third embodiment, concave portions11dformed by notching lead regions of the electrode terminal plates (23and33) into rectangular shapes are formed.

Then, the outer shapes of the two laminated films (11aand11b) are plane-symmetrical in the up and down direction. The two strip-shaped tab films (14aand14b) have identical shapes, and sandwich the positive electrode terminal plate23and the negative electrode terminal plate33together in a state where the two strip-shaped tab films (14aand14b) have outer shapes aligned with one another. The front margin113is aligned with front margins of the terminal lead margins (13aand13b) of the upper and lower laminated films (11aand11b). Then, after the peripheral edge regions12of the two laminated films (11aand11b) are welded, the two tab films (14aand14b) are welded to one another in a state of sandwiching the electrode terminal plates (23and33).

If the peripheral edge regions12of the two laminated films (11aand11b) are welded, as illustrated inFIG. 12B, in the exterior body11, the concave portions11dare formed in a region including the regions where the electrode terminal plates (23and33) are guided, at the terminal lead margin13. Then, at the tab films14, expose surfaces14dof front-end-side both upper and lower surfaces are exposed outward in the regions on which the above-described concave portions11dare formed, and rear end sides are interposed between the two laminated films (11ato11b). At the regions except for the concave portions11d, the tab films14are arranged so as to be aligned with the outer shape of the exterior body11. Accordingly, as illustrated inFIG. 12C, the electrode terminal plates (23and33) have top surfaces and lower surfaces covered with the tab films14in the regions where the above-described concave portions11dare formed at the terminal lead margins (13aand13b) of the two laminated films (11aand11b). Therefore, the electrode terminal portions (25and35) do not contact the cutting surfaces11cof the laminated films (11aand11b) even if the electrode terminal portions (25and35) are folded on any of the upper side and the lower side.

In the laminate-type power storage element1daccording to the third embodiment, at the two laminated films (11aand11b) that constitute the exterior body11, it is only necessary to dispose the concave portions11dthat are plane-symmetrical in the up and down direction in the regions where the electrode terminal plates (23and33) are guided. This surely ensures prevention of the short circuit almost without the cost increase. Then, at both right and left ends of the terminal lead margins (13aand13b) of the laminated films (11aand11b), the front margins113of the tab films14do not project ahead of the exterior body11. Therefore, the positioning accuracy when the two laminated films (11aand11b) are laminated in the sealing process can be maintained, thus as illustrated inFIG. 5, ensuring positioning based on the outer shape of the lower laminated film11a.

Needless to say, the base ends (26and36) of the electrode terminal portions (25and35) are covered with the tab films14made of resin. Thus, the electrode terminal plates (23and33) are not bent at the acute angle taking the terminal lead margins (13aand13b) of the laminated films (11aand11b) as the fulcrums. That is, the laminate-type power storage element1daccording to the third embodiment can prevent the break of the electrode terminal plates (23and33) taking the terminal lead margins (13aand13b) as the edges.

In the laminate-type power storage element1daccording to the present embodiment, it is only necessary to form the concave portions11das encompassing the regions where the electrode terminal plates (23and33) are guided, at the terminal lead margins13.

For example, as in a laminate-type power storage element1eillustrated inFIG. 13, the concave portions11dthat are wide to right and left may be formed at the terminal lead margins13. In any case, at the terminal lead margins13, insofar as the concave portions11dare not formed in the regions on which the positioning jig200illustrated inFIG. 5abuts, positioning can be performed based on the outer shapes of the laminated films (11aand11b).

Reliability Test

Next, the laminate-type power storage element1dillustrated inFIG. 12AtoFIG. 12Cand the laminate-type power storage element102illustrated inFIG. 2Awere manufactured as the samples. Then, the following bending test was performed for each sample. The electrode terminal plates (23and33) of the positive electrode20and the negative electrode30were bent upward and downward at an angle of 90° at the parts of the base ends (26and36) of the electrode terminal portions (25and35). Thus, the presence/absence of the short circuit between the positive electrode terminal plate23and the negative electrode terminal plate33was examined. Here, for each sample, 30 pieces of individuals were manufactured. The bending test was performed for total 60 pieces of individuals. As a result, in the sample of the laminate-type power storage element1daccording to the present embodiment, the short circuit did not occur in all the 30 pieces of individuals even when the electrode terminal plates (23and33) were bent upward and downward. On the other hand, in the sample of the laminate-type power storage element102, the short circuit occurred in 28 pieces of individuals when the electrode terminal plates (23and33) were bent in any of upper and lower directions.

As described above, it was confirmed that the laminate-type power storage element1daccording to the present embodiment, without the protective tape, surely prevents the short circuit due to the contact between the metal foils exposed on the cutting surfaces11cof the laminated films (11aand11b) and the electrode terminal portions (25and35), and has the high reliability.

Other Working Examples

The laminate-type power storage elements (1dand1e) according to the third embodiment are “the single-layer type” that houses, within the exterior body11, the electrode body10including one each of the sheet-shaped positive electrode20and negative electrode30. However, the laminate-type power storage elements (1dand1e) may be “the multilayer type” including the electrode bodies10for a plurality of layers.

The single-layer type power storage elements1dand1eeach have a basic structure to achieve thinning by including only the smallest number of electrode bodies10. Then, the laminate-type power storage elements1dand1eaccording to the present embodiment each has a structure that can prevent the short circuit using the tab films (14aand14b) and without the protective tape, thus achieving further thinning with respect to the basic structure.

Needless to say, even for the laminate-type power storage elements1dand1eincluding the multilayer type electrode bodies10, the cost reduction can be expected by eliminating the need of the protective tapes that insulate the cutting surfaces11cof the laminated films (11aand11b) and the sticking process of these protective tapes.

In the laminate-type power storage elements (1dand1e) according to the present embodiment, the positive electrode terminal plate23and the negative electrode terminal plate33are guided from the exterior body11in the identical direction. However, the positive electrode terminal plate23and the negative electrode terminal plate33may be guided in opposite directions from two margins13opposed to one another at the exterior body11. Needless to say, the electrode terminal plates (23and33) may be guided in directions that intersect with one another, such as two margins13adjacent to one another on the rectangular planar surface.

In the laminate-type power storage elements (1dand1e) according to the third embodiment, the exterior body11having the rectangular-planar-shaped or straight terminal lead margin13is used in that the general-purpose strip-shaped tab film14can be used. However, it is not necessary that the outer shape of the exterior body11and the terminal lead margin13are rectangular or straight. The exterior body11may have an appropriate planar shape such as circular or polygonal. The terminal lead margin13may be a curved line.

In any case, it is only necessary that the electrode terminal plates (23and33) are guided from predetermined regions at the peripheral edge of the exterior body11, the concave portions11dare formed in the region including the predetermined regions so that the laminated films (11aand11b) opposed to one another are plane-symmetrical in the up and down direction, and the tab films14are disposed aligned with the outer shape of the exterior body11outside the formation regions of the concave portions11d.

The laminate-type power storage elements1dand1eaccording to the third embodiment are applicable to various kinds of storage elements (for example, a lithium secondary battery and an electric double layer capacitor), not limited to the lithium primary battery, insofar as the laminate-type power storage elements1dand1eeach have a structure that seals the flat plate-shaped electrode body10into the flat-bag-shaped exterior body11constituted of the laminated films (11aand11b). Needless to say, the laminate-type power storage elements1dand1eare applicable to a power storage element where the electrolyte is immersed in a polymer, such as a polymer battery. The laminate-type power storage elements1dand1eare applicable to a power storage element without electrolyte itself, such as an all-solid battery.

FIG. 14illustrates a structure of a laminate-type power storage element1fusing the all-solid battery111. The all-solid battery111housed in the exterior body11has a structure where the current collectors (131and121) constituted of the metal foils are formed on the top surface and the lower surface of the laminated electrode body110formed by sandwiching the sheet-shaped solid electrolyte (solid electrolyte layer)140between the sheet-shaped positive electrode (positive electrode layer)120and the sheet-shaped negative electrode (negative electrode layer)130.

The laminated electrode body110is an integral sintered body. A method of manufacturing the laminated electrode body110includes a method of sintering a formed body obtained by pressurizing raw material powder using a mold (hereinafter referred to as a compression molding method), a well-known method using a green sheet (hereinafter, a green sheet method), and similar method. In the compression molding method, powder positive electrode layer material including a positive-electrode active material and a solid electrolyte, which will be raw materials of the positive electrode layer120, powder solid electrolyte, which will be a raw material of the solid electrolyte layer140, and powder negative electrode layer material including a negative electrode active material and a solid electrolyte, which will be raw materials of the negative electrode layer130are sequentially filled in the mold with laminated shapes (sheet shapes). Next, the powder raw materials of the respective layers laminated into sheet shapes are pressurized in their laminating direction to obtain a formed body. The formed body is sintered. Accordingly, the laminated electrode body110constituted of the integrated sintered body is manufactured.

In the green sheet method, slurry positive electrode layer material including the positive-electrode active material and the solid electrolyte, slurry negative electrode layer material including the negative electrode active material and the solid electrolyte, and slurry solid electrolyte layer material including the solid electrolyte each are shaped into a sheet-shaped green sheet, and a laminated body formed by sandwiching the green sheet of the solid electrolyte layer material between the green sheets of the positive electrode layer material and the negative electrode layer material is sintered to manufacture the laminated electrode body110.

Then, the all-solid battery111is completed by applying silver paste or by evaporating gold or the like over the top surface and the lower surface of the manufactured laminated electrode body110to form the current collectors (121and131).

Then, when this all-solid battery111is housed in the exterior body11constituted of the laminated films (11aand11b), it is only necessary to mount the strip-shaped electrode terminal plates (23and33) to the current collectors (121and131) to guide these electrode terminal plates (23and33) outward from the exterior body11.

The laminate-type power storage element according to the present disclosure has a high reliability including a structure that achieves the cost reduction and thinning and surely ensures prevention of short circuit between the electrode terminal plates. The method of manufacturing the laminate-type power storage element according to the present disclosure ensures manufacture of the laminate-type power storage element that is inexpensive and thin, and has high reliability.

The embodiments are intended for easy understanding of the present disclosure and are not in any way to be construed as limiting the present disclosure. The present disclosure may be modified and improved without departing from the scope thereof, and equivalents thereof are also encompassed by the present disclosure.