JP6868399B2 - Laminated power storage element - Google Patents

Description

The present invention relates to a laminated power storage element.

The laminated type power storage element is formed by accommodating a flat electrode body having a sheet-shaped positive electrode and a negative electrode inside a flat bag-shaped exterior body made of a laminated film. Laminated power storage elements are suitable for miniaturization and thinning. For example, an IC card equipped with a one-time password function and a display, an IC card with a display, or a tag or token (one-time password generator) with a built-in power supply. It is used as a power source for extremely thin electronic devices (hereinafter referred to as thin electronic devices).

FIG. 1 shows an example of a conventional laminated type power storage element. The laminated type power storage element illustrated in FIG. 1 is a lithium primary battery using a non-aqueous electrolytic solution, FIG. 1 (A) is an external view of the laminated type power storage element 101, and FIG. 1 (B) is a laminated type power storage element. It is an exploded perspective view which shows an example of the internal structure of the element 101. As shown in FIG. 1A, the laminated power storage element 101 has a flat plate-like external shape, and the power generation element is sealed in the exterior body 11 in which the laminated film is formed into a flat rectangular bag shape. There is. Further, in the laminated type power storage element 101 shown here, the positive electrode terminal plate 23 and the negative electrode terminal plate 33 are led out outward from a predetermined edge 13 of the rectangular exterior body 11.

Next, the structure of the laminated power storage element 101 will be described with reference to FIG. 1 (B). In FIG. 1B, some members and parts are hatched so as to be easily distinguished from other members and parts. As shown in FIG. 1B, an electrode body 10 in which a sheet-shaped positive electrode 20 and a sheet-shaped negative electrode 30 are laminated via a separator 40 is enclosed in the exterior body 11 together with an electrolytic solution. There is. The positive electrode 20 is a positive electrode material 22 containing a positive electrode active material arranged on one main surface of a positive electrode current collector 21 made of a metal plate or a metal foil, and a negative electrode 30 is a negative electrode current collector made of a metal plate or a metal foil. The negative electrode material 32 containing the negative electrode active material is arranged on one main surface of the body 31. The electrode body 10 is formed by laminating and crimping the positive electrode 20 and the negative electrode 30 so that the respective electrode materials (22, 32) face each other via the separator 40.

The exterior body 11 has two rectangular aluminum laminated films (11a-11b) that are superposed on each other, and the peripheral region 12 shown by the shaded hatching or the dotted frame in the figure is welded by a thermocompression bonding method to form the inside. It is hermetically sealed. As is well known, the laminated film (11a, 11b) has a structure in which one or more resin layers are laminated on the front and back of a metal foil (aluminum foil, stainless foil, etc.) as a base material, and is generally used. A protective layer made of, for example, a polyamide resin is laminated on the front surface which is the outer surface of the exterior body 11, and a heat-welding adhesive layer such as polypropylene is laminated on the back surface which is the inner surface of the exterior body 11. It has a structure.

By the way, the positive electrode current collector 21 and the negative electrode current collector 31 on which the positive electrode material 22 and the negative electrode material 32 are laminated are naturally electrically connected to the positive electrode terminal plate 23 and the negative electrode terminal plate 33, and the positive electrode is electrically connected to the positive electrode terminal plate 23 and the negative electrode terminal plate 33. The terminal plates of 20 and the negative electrode 30 (hereinafter, also referred to as electrode terminal plates (23, 33)) are led out to the outside of the outer body 11 in a sealed state. Therefore, at the edge edges (hereinafter, also referred to as terminal lead-out edge edges 13) from which the electrode terminal plates (23, 33) are derived in the exterior body 11, the electrode terminal plates are simply welded together with the adhesive layers of the laminated films (11a, 11b). In some cases, sufficient adhesion strength between (23, 33) and the laminated film (11a, 11b) cannot be ensured.

Further, in the terminal lead-out edge 13, it is difficult to intervene the adhesive layer in a molten state over the thickness direction of the electrode terminal plates (23, 33), and the edge 13 is not sufficiently sealed and the waterproof property is lowered. there's a possibility that. Therefore, the laminated power storage element 101 has a structure for securely sealing the terminal lead-out edge 13 in the exterior body 11. As a sealing method for the terminal lead-out edge 13, a method in which the tab lead 50 is used as the electrode terminal plate (23, 33), or a band-shaped metal foil or metal plate on the current collectors (21, 31) of the positive electrode 20 and the negative electrode 30 is used. (Hereinafter, terminal leads) may be attached and the terminal leads may be used as they are as electrode terminal plates (23, 33).

FIG. 1B shows a method using the tab lead 50, and electrode terminal plates (23, 33) made of the tab lead 50 are connected to each of the positive electrode current collector 21 and the negative electrode current collector 31. .. As described in Patent Document 1, for example, the tab lead 50 is insulated in the process of extending a band-shaped terminal lead 51 made of a metal plate, a metal foil, or the like, which is a substantial electrode terminal plate (23, 33). It has a structure in which a resin sealing material (hereinafter, tab film 52) is adhered so as to sandwich the terminal lead 51. One end 53 of the terminal lead 51 is exposed to the outside of the exterior body 11, and the other end is connected to a part of the positive electrode current collector 21 and the negative electrode current collector 31 by a method such as ultrasonic welding. .. Of course, it is also possible to attach a separate strip-shaped metal plate or metal foil to the positive electrode current collector 21 and the negative electrode current collector 31, and further connect the tab lead 50 to the metal plate or metal foil. Then, when the peripheral regions 12 of the laminated films (11a, 11b) facing each other are thermocompression-bonded to form a flat bag-shaped exterior body 11, in the peripheral region 12 of the exterior body 11, the tab lead 50 is formed at the terminal lead-out edge 13. The tab film 52 is thermowelded together with the laminated films (11a, 11b). As a result, at the edge 13, the tab film 52 welded to the terminal lead 51 is welded to the adhesive layer of the laminated film (11a, 11b).

On the other hand, in the method of using the terminal lead as it is as the electrode terminal plate without using the tab lead, a method of attaching a separate terminal lead to the positive electrode current collector or the negative electrode current collector, or the positive electrode current collector and the negative electrode current collector. There is a method in which a band-shaped convex portion corresponding to a terminal lead is integrally formed on each body, and the convex portion is used as an electrode terminal plate. FIG. 2 shows an exploded perspective view of a laminated power storage element (102, 103) adopting a method that does not use a tab lead. FIG. 2A shows a laminated power storage element 102 corresponding to a method in which electrode terminal plates (23, 33) made of separate terminal leads are attached to a positive electrode current collector 21 or a negative electrode current collector 31. FIG. 2B shows a laminated power storage element 103 in which the positive electrode current collector 21 and the negative electrode current collector 31 are provided with convex portions (24, 34) that also serve as electrode terminal plates (23, 33). Then, as shown in FIGS. 2 (A) and 2 (B), in the power storage element (102, 103) adopting the method of not using the lead tab, a strip-shaped tab film (14a, 14b) is used instead of the tab lead. A method of sealing the terminal lead-out edge 13 by using the terminal is adopted. In this method, in the peripheral region 12 of the exterior body 11, a strip-shaped tab film (14a, 14b) is preliminarily welded to the back surface of the laminated film (11a, 11b) on the terminal lead-out edge 13 and then thermocompression bonded. On that surface, the peripheral region 12 of the laminated film (11a, 11b) is thermocompression bonded to form the exterior body 11. That is, in the laminated films (11a, 11b) facing each other, the laminated films (11a-11b) are adhered to each other via the band-shaped tab films (14a, 14b) at the terminal lead-out edge 13. The following Non-Patent Document 1 describes a thin lithium battery which is a laminated type power storage element.

Japanese Unexamined Patent Publication No. 2008-192451

FDK Corporation, "Thin Lithium Primary Battery", [online], [Search on December 1, 2016], Internet <URL: http://www.fdk.co.jp/battery/lithium/lithium_thin.html>

As described above, the laminated power storage element has a structure in which an electrode terminal plate is led out from an outer body formed into a flat bag shape by thermocompression bonding the facing laminated films to each other. As a method for sealing the terminal lead-out edge of the exterior body, there are generally a method using a tab lead (hereinafter, also referred to as a tab lead method) and a method using a strip-shaped tab film (hereinafter, also referred to as a tab film method). At present, the tab lead method is the mainstream, but in this method, the terminal leads of the tab leads are ultrasonically welded to the electrode current collector, which increases the man-hours for assembling the laminated storage element and is an expensive ultrasonic welding machine. There is also a problem of increasing the manufacturing cost of the laminated type power storage element because it is necessary. Further, the tab lead, which is an indispensable member, is a member sold as an industrial product manufactured separately from the power storage element, and the tab lead method has a higher member cost than the tab film method.

On the other hand, the tab film method does not require a tab lead, which is an expensive member, and can be applied to an electrode body having a structure in which an electrode terminal plate and an electrode body are integrated in advance. Therefore, the tab film method is overwhelmingly more advantageous than the tab lead method in terms of price reduction and versatility. When a laminated type power storage element suitable for miniaturization and thinning is used in a large amount and at an extremely low price, and in some cases, for an application such as an IC card provided free of charge, the price is lower than that of the laminated type power storage element. Is required as an extremely important matter. Therefore, it is expected that the tab film type laminated power storage element will become the mainstream in the future.

Therefore, when the present inventor examined the reliability of the tab film type laminated power storage element, it was found that there was a problem that the reliability was lowered due to the structure of the laminated film. FIG. 3 shows a diagram for explaining the problem. FIG. 3 is a side view of the state in which the conventional laminated type power storage element 102 shown in FIG. 2A is incorporated in a thin electronic device, as viewed from the thickness direction of the laminated type power storage element 102.

As shown in FIG. 3, when the laminated type power storage element 102 is incorporated in a thin electronic device, a region of the electrode terminal plates (23, 33) protruding outward from the exterior body 11 (hereinafter, electrode terminal portions (25, 33)). 35)) is connected to the circuit board 100. At this time, for example, the electrode terminal portions (25, 35) may be bent like a crank. Then, when the base ends (26, 36) sides of the electrode terminals (25, 35) of the positive electrode and the negative electrode were bent with the terminal lead-out edge 13 as a fulcrum, they were exposed on the cut surface 11c of the laminated film (11a, 11b). The electrode terminal plates (23, 33) may come into contact with the metal foil, causing a short circuit between the positive electrode and the negative electrode. It is also conceivable to attach an insulating tape (hereinafter, also referred to as a protective tape) that protects the cut surface 11c of the laminated film (11a, 11b) to prevent a short circuit, but this protective tape is a laminated type power storage element. In addition to hindering the thinning of the protective tape, the cost of members for the protective tape and the addition of a process for attaching the protective tape also hinder the price reduction.

Therefore, an object of the present invention is to provide a laminated type power storage element which is suitable for price reduction and thinning, and has a structure capable of surely preventing a short circuit between electrode terminal plates.

The present invention for achieving the above object is a laminated type power storage element in which an electrode body having a sheet-shaped positive electrode and a negative electrode is sealed inside a bag-shaped outer body that is flat in the vertical direction.
The strip-shaped positive electrode and negative electrode terminal plates connected to the positive electrode and the negative electrode, respectively, are derived from a predetermined edge on the peripheral edge of the exterior body.
The exterior body is made of two laminated films in which insulating resin layers are formed on both the front and back surfaces of the base material of the metal foil, and the end face of the metal foil is exposed at the predetermined edge.
The two laminated films are welded to each other in a region that orbits a planar shape while facing each other in the vertical direction, and are welded via a tab film that sandwiches the electrode terminal plate in the vertical direction at the predetermined edge. Being done
The positive electrode and negative electrode terminal plates are derived from a recessed region formed by cutting out a part of the predetermined edge.
The upper surface and the lower surface of the tab film are exposed to the outside at the recess, and the tab film is arranged at the predetermined edge so as to be aligned with the outer shape of the exterior body outside the region where the recess is formed.
It is a laminated type power storage element characterized by this. Then, it is preferable that the laminated type power storage element includes only one sheet-shaped positive electrode and one negative electrode.

According to the laminated type power storage element according to the present invention, high reliability can be realized by providing a structure that can achieve low price and thinness and surely prevent short circuits between electrode terminal plates. Other effects will be clarified in the following description.

It is a figure which shows the example of the conventional laminated type power storage element which adopted the tab lead system. It is a figure which shows the example of the conventional laminated type power storage element which adopted the tab film system. It is a figure for demonstrating the problem of the conventional laminated film which adopted the tab film system. It is a figure which shows the laminated type power storage element which made the prototype in order to solve the said problem. It is a figure which shows the alignment jig used when manufacturing the conventional laminated type power storage element. It is a figure for demonstrating the problem at the time of manufacturing the said prototype laminated type power storage element using the said alignment jig. It is a figure which shows the laminated type power storage element which concerns on embodiment of this invention. It is a figure which shows the modification of the laminated type power storage element which concerns on the said Example. It is a figure which shows the laminated type power storage element which concerns on other Examples of this invention.

Examples of the present invention will be described below with reference to the accompanying drawings. In the drawings used in the following description, the same or similar parts may be designated by the same reference numerals and duplicate description may be omitted. A coded part in one drawing may not be coded in another drawing if it is not necessary.

=== Process of reaching the invention of the present application ===
As described above, in the conventional laminated type power storage element, the cross section of the metal leaf of the laminated film is exposed on the terminal lead-out edge of the exterior body, and the electrode terminal plate may come into contact with the cross section to cause a short circuit. .. Further, with the conventional laminated type power storage element, it is difficult to solve the problem of this short circuit while achieving both thinness and price reduction. Therefore, if the band-shaped tab film used for sealing the terminal lead-out edge has the same function as the protective tape, the present inventor does not cause a short circuit because the electrode terminal portion does not come into direct contact with the cut surface of the laminated film. It was thought that additional members such as protective tape would not be required, and the thickness could be the same as that of the conventional laminated type power storage element.

FIG. 4 shows a laminated type power storage element (104, 105) in which a strip-shaped tab film (14, 114) is provided with the function of a protective tape. In the laminated type power storage element 104 shown in FIG. 4A, the tab film 14 is projected from the terminal lead-out edge 13 by a predetermined width w. As a result, even if the electrode terminal plates (23, 33) are bent, the tab film 14 covers the cut surface 11c of the laminated film (11a, 11b), and a short circuit can be prevented. In the laminated type power storage element 105 shown in FIG. 4 (B), as shown in FIG. 4 (C), a tab film 114 provided with a convex portion 115 along the lead-out shape of the electrode terminal plates (23, 33) is provided. In use, only this convex portion 115 protrudes from the terminal lead-out edge 13 and covers the base end (26, 36) of the electrode terminal portion (25, 35).

Then, when two types of laminated type power storage elements (104, 105) shown in FIGS. 4 (A) and 4 (B) were actually prototyped, both laminated type power storage elements (104, 105) were found. It was confirmed that a short circuit could be prevented. However, on the other hand, matters to be examined were discovered in the process of manufacturing these laminated type power storage elements (104, 105). First, in the laminated type power storage element 104 shown in FIG. 4A, the peripheral region 12 is accurately pressed in the sealing step of thermocompression bonding the peripheral region 12 of the laminated film (11a, 11b) to seal the inside of the exterior body 11. There was a problem that it was difficult to form. Specifically, in the sealing step, it is necessary to laminate the two laminated films (11a-11b) in a state of being accurately aligned with each other. When the peripheral region 12 is formed by thermocompression bonding, it is necessary to prevent the thermocompression bonding jig from coming into contact with the storage region of the electrode body and damaging the electrode body. Therefore, in the sealing step, as shown in FIG. 5, a jig (hereinafter, also referred to as an alignment jig 200) that surrounds the outer shape of the rectangular laminated film (11a, 11b) is used, and the laminated film (11a, 11b) is used. ) Is used as a reference for alignment. Although the alignment jig 200 has a simple structure, alignment can be performed extremely accurately and easily as long as the dimensional accuracy of the laminated films (11a, 11b) can be ensured. Therefore, in order to manufacture the laminated power storage elements (104, 105) at a lower cost, it is desirable to use the alignment jig 200.

However, when the tab film 14 is projected from the terminal lead-out edge 13 with a uniform width w as in the laminated type power storage element 104 shown in FIG. 4 (A), the protruding tab film 14 is present, so that the laminated film ( Alignment using the outer shape of 11a, 11b) is not possible. It is conceivable to use an alignment jig having a surrounding shape and size in consideration of the protruding width w of the tab film 14, but the tab film 14 is made of a film made of a resin such as polyethylene naphthalate (PEN) as a substrate. It is a three-layer structure in which an adhesive layer made of a thermoplastic resin (for example, modified polypropylene such as PPa) is formed on both the front and back surfaces of a substrate, or a strip-shaped film composed of a single adhesive layer without a substrate. Therefore, when the terminal lead-out edge 13 is sealed, the region of the tab film 14 protruding from the exterior body 11 may be melted and deformed, and the position may shift during the sealing process. It is conceivable to seal the three sides other than the terminal lead-out edge 13 and finally seal the terminal lead-out edge 13, but as shown in FIG. 6, the edge 113 of the tab film 14 is used for alignment. When the tab film 14 is brought into contact with the alignment jig 200, the tab film 14 itself is easily deformed as shown in the circular frame 201 in the drawing, and the alignment accuracy cannot be ensured. That is, the outer shape of the tab film (14a, 14b) cannot be used as a reference for alignment.

On the other hand, in the method shown in FIG. 4B, only the convex portion 115 of the tab film 114 protrudes from the terminal lead-out edge 13. Therefore, even if the alignment jig 200 shown in FIG. 5 is used, the alignment can be performed with the outer shape of the laminated film (11a, 11b). However, as a pre-process for laminating the two laminated films (11a, 11b), a step of accurately aligning the convex portion 115 with the lead-out position of the electrode terminal plate (23, 33) is required, which may increase the manufacturing cost. is there. Further, a tab film 114 having a convex portion 115 provided with respect to the conventional simple strip-shaped tab film 14 will be specially prepared, and the tab film 114 provided with the convex portion 115 may be a factor of increasing the member cost. ..

Therefore, it is desirable that the laminated type power storage element has a structure capable of aligning with reference to the outer shape of the laminated film in the sealing process without using a tab film having a complicated shape. Of course, even if the structure is adopted, it is necessary to have a structure that can maintain the thinness equal to or higher than the conventional one without increasing the cost. Then, the present inventor has made extensive studies on the structure of a laminated power storage element that can meet these demands, and came up with the present invention.

=== Example ===
FIG. 7 shows the laminated type power storage element 1a according to the embodiment of the present invention. FIG. 7A is an exploded perspective view of the laminated power storage element 1a, and FIG. 7B is a perspective view showing the appearance of the laminated power storage element 1a. Further, FIG. 7C is an enlarged view of a part of the cross section taken along the arrow aa in FIG. 7B. In the following, as shown in the figure, in the laminated type power storage element 1a, in the thickness direction of the flat bag-shaped exterior body 11, that is, the power generation elements in the two laminated films (11a, 11b) and the electrode body 10 ( The stacking direction of 20, 30, 40) is the vertical direction, and the protruding direction of the electrode terminal plates (23, 33) is the front-rear direction. Further, the direction orthogonal to each direction of up, down, front and back is defined as the left and right direction. In the following, each direction of up, down, left, right, front and back will be defined as a perspective view of FIGS. 7A and 7B as viewed from the upper right front.

As shown in FIG. 7A, electrode terminal plates (23) are attached to the terminal lead-out edges (13a, 13b) of the two laminated films (11a, 11b) constituting the laminated power storage element 1a of this embodiment. , 33) is formed with a recess 11d in which the derived region is cut out in a rectangular shape. The outer shapes of the two laminated films (11a, 11b) are plane-symmetrical in the vertical direction. Further, the two strip-shaped tab films (14a, 14b) have the same shape, and the electrode terminal plates (23, 33) of the positive electrode 20 and the negative electrode 30 are collectively sandwiched in a state where the outer shapes are aligned with each other. The front edge 113 is aligned with the front edge of the terminal lead-out edge (13a, 13b) of the upper and lower laminated films (11a, 11b). Then, when the peripheral regions 12 of the two laminated films (11a, 11b) are welded, the two tab films (14a, 14b) are welded to each other with the electrode terminal plates (23, 33) sandwiched.

When the peripheral regions 12 of the two laminated films are welded, as shown in FIG. 7 (B), the exterior body 11 has the regions where the electrode terminal plates (23, 33) are led out at the terminal lead-out edge 13. A recess 11d is formed in the including region. Then, in the tab film 14, the upper and lower surfaces 14c on the front end side are exposed to the outside in the region where the recess 11d is formed, and the rear end side is interposed between the two laminated films (11a-11b). Further, in the region other than the recess 11d, the outer body 11 is arranged so as to be aligned with the outer shape of the exterior body 11. Therefore, as shown in FIG. 7C, the electrode terminal plates (23, 33) have the recesses 11d formed at the terminal lead-out edges (13a, 13b) of the two laminated films (11a, 11b). The upper surface and the lower surface are covered with the tab film 14 in the present area. Therefore, the electrode terminal portions (25, 35) do not come into contact with the cut surface 11c of the laminated film (11a, 11b) regardless of whether they are bent upward or downward.

Further, in the laminated power storage element 1a of the present embodiment, the two laminated films (11a, 11b) constituting the exterior body 11 are plane-symmetrical in the vertical direction with respect to the region where the electrode terminal plates (23, 33) are led out. It is only necessary to provide the recess 11d to be provided, and a short circuit can be reliably prevented with almost no increase in cost. The front edge 113 of the tab film 14 does not project forward of the exterior body 11 at the left and right ends of the terminal lead-out edges (13a, 13d) of the laminated film (11a, 11b). Therefore, when the two laminated films (11a, 11b) are laminated in the sealing step, the problem of alignment as shown in FIG. 6 does not occur, and as shown in FIG. 5, the lower laminated film 11a It is possible to align with reference to the outer shape of. Of course, since the base ends (26, 36) of the electrode terminal portions (25, 35) are covered with the tab film 14 made of resin, the electrode terminal plates (23, 33) are made of the laminated film (11a, 11b). It does not bend sharply with the terminal lead-out edges (13a, 13b) as fulcrums. That is, in the laminated type power storage element 1a of this embodiment, it is possible to prevent the electrode terminal plates (23, 33) from being broken with the terminal lead-out edge edges (13a, 13b) as edges.

In the laminated type power storage element 1a of this embodiment, it is sufficient that the recess 11d is formed in the terminal lead-out edge 13 so as to include the region where the electrode terminal plates (23, 33) are led out. For example, as in the laminated power storage element 1b shown in FIG. 8, wide recesses 11d may be formed on the left and right sides of the terminal lead-out edge 13. In any case, if the recess 11d is not formed in the region where the alignment jig 200 shown in FIG. 5 abuts on the terminal lead-out edge 13, the alignment is performed with reference to the outer shape of the laminated film (11a, 11b). Can be done.

=== Reliability test ===
Next, the laminated type power storage element 1a according to the embodiment shown in FIG. 7 and the conventional laminated type power storage element 102 shown in FIG. 2 were produced as samples. Then, for each sample, the electrode terminal plates (23, 33) of the positive electrode and the negative electrode are bent upward and downward at an angle of 90 ° at the base ends (26, 36) of the electrode terminal portions (25, 35). A bending test was performed to check for a short circuit between the positive electrode terminal plate and the negative electrode terminal plate (23-33). Here, 30 individuals were prepared for each sample, and a bending test was performed on a total of 60 individuals. As a result, in the sample of the laminated type power storage element 1a according to the example, even if it was bent upward and downward, a short circuit did not occur in all 30 individuals. On the other hand, in the sample of the conventional laminated type power storage element 102, a short circuit occurred when the 28 individuals were bent in either the upper or lower direction. From the above, the laminated type power storage element 1a according to the embodiment is short-circuited by contact between the metal foil exposed on the cut surface 11c of the laminated film (11a, 11b) and the electrode terminal portions (25, 35) without using the protective tape. It was confirmed that it has high reliability by surely preventing.

=== Other Examples ===
The laminated type power storage element (1a, 1b) according to the above embodiment is a "layer type" in which an electrode body 10 having one sheet-shaped positive electrode 20 and one negative electrode 30 is housed in the exterior body 11. The present invention can also be applied to a "multilayer" laminated power storage element having a plurality of layers of electrodes. Certainly, the conventional single-layer power storage element has only the smallest number of electrode bodies and has a basic structure for achieving thinning. The laminated type power storage element according to the embodiment has a structure capable of preventing a short circuit without using a protective tape while using a tab film, and further thinning of the basic structure can be achieved. Of course, even in the case of a laminated power storage element provided with a multilayer electrode body, cost reduction can be expected by eliminating the need for a protective tape that insulates the cut surface of the laminated film and a step of attaching the protective tape.

In the laminated power storage elements (1a, 1b) according to the above embodiment, the positive electrode terminal plate 23 and the negative electrode terminal plate 33 are led out from the exterior body 11 in the same direction, but the positive electrode terminal plate 23 and the negative electrode terminal plate 33 are In the exterior body 11, the two edges facing each other may be derived in opposite directions. Of course, the electrode terminal plates (23, 33) may be derived in the direction in which they intersect with each other, such as two adjacent edges in a rectangular plane.

In the laminated type power storage elements (1a, 1b) according to the above embodiment, an exterior body 11 having a rectangular flat shape or a linear terminal lead-out edge 13 is used in that a general-purpose strip-shaped tab film 14 can be used. Was there. However, the outer shape of the exterior body 11 and the terminal lead-out edge 13 do not have to be rectangular or straight, and the exterior body 11 can have an appropriate planar shape such as a circle or a polygon. The terminal lead-out edge 13 may be curved. In any case, the electrode terminal plates (23, 33) are derived from a predetermined region on the peripheral edge of the exterior body 11, and the laminated films (11a, 11b) facing each other in the region including the region are plane-symmetrical in the vertical direction. It suffices that the recess 11d is formed so as to be such that the tab film 14 is arranged outside the formation region of the recess 11d so as to be aligned with the outer shape of the exterior body 11.

The laminated type power storage element according to the embodiment of the present invention is not limited to a lithium primary battery, as long as it has a structure in which a flat plate-shaped electrode body is sealed inside a flat bag-shaped exterior body made of a laminated film, and various types of power storage elements are used. It can be applied to (lithium secondary batteries, electric double layer capacitors, etc.). Of course, it can also be applied to a power storage element in which a polymer is impregnated with an electrolytic solution, such as a polymer battery. It can also be applied to a power storage element that does not use the electrolytic solution itself, such as an all-solid-state battery.

FIG. 9 shows the structure of the laminated power storage element 1c using the all-solid-state battery 111. The all-solid-state battery 111 housed in the exterior body 11 has a sheet-shaped solid electrolyte (solid electrolyte layer) 140 between the sheet-shaped positive electrode (positive electrode layer) 120 and the sheet-shaped negative electrode (negative electrode layer) 130. It has a structure in which current collectors (131, 121) made of metal foil are formed on the upper surface and the lower surface of the laminated electrode body 110 which is sandwiched. The laminated electrode body 110 is an integral sintered body, and as a method for manufacturing the laminated electrode body 110, a method of firing a molded body obtained by pressurizing a raw material powder using a mold (hereinafter referred to as a compression molding method). There are methods using a well-known green sheet (hereinafter, also referred to as a green sheet method). In the compression molding method, a powdery positive electrode layer material containing a positive electrode active material and a solid electrolyte as a raw material for the positive electrode layer 120, a powdery solid electrolyte as a raw material for the solid electrolyte layer 140, and a negative electrode are contained in a mold. A powdery negative electrode layer material containing a negative electrode active material and a solid electrolyte as a raw material of the layer 130 is sequentially filled in a layered form (sheet form). Next, the molded product obtained by pressurizing the powder raw material of each layer laminated in the form of a sheet in the laminating direction is fired. As a result, the laminated electrode body 110 made of an integral sintered body is produced.

In the green sheet method, a slurry-like positive electrode layer material containing a positive electrode active material and a solid electrolyte, a slurry-like negative electrode layer material containing a negative electrode active material and a solid electrolyte, and a slurry-like solid electrolyte layer material containing a solid electrolyte are each sheeted. The laminated electrode body 110 is produced by molding the green sheet into a shaped green sheet and firing the laminated body in which the green sheet of the solid electrolyte layer material is sandwiched between the green sheet of the positive electrode layer material and the green sheet of the negative electrode layer material. Then, the all-solid-state battery 111 is completed by applying silver paste to the upper surface and the lower surface of the produced laminated electrode body 110 or depositing gold or the like to form current collectors (121, 131). Then, when the all-solid-state battery 111 is housed in the exterior body 11 made of the laminated film (11a, 11b), the band-shaped electrode terminal plates (23, 33) are attached to the current collectors (121, 131). The electrode terminal plates (23, 33) may be led out to the outside of the exterior body 11.

1a to 1c, 101 to 105 Laminated power storage element, 10 electrode body, 11 exterior body,
11a, 11b laminated film, 12 peripheral areas,
13, 13a, 13b terminal lead-out edge,
14, 14a, 14b, 52, 114 tab film, 11d recess, 20 positive electrode, 21 positive electrode current collector, 23 positive electrode terminal plate, 25 electrode terminal part of positive electrode terminal plate, 26 base end of electrode terminal part of positive electrode,
30 Negative electrode, 33 Negative electrode terminal plate, 31 Negative electrode current collector, 35 Electrode terminal part of Negative electrode terminal plate,
36 Base end of electrode terminal of negative electrode, 40 separator, 50 tab lead,
110 All-solid-state battery laminated electrode body, 111 All-solid-state battery,
113 tab film front edge, 120 positive electrode layer, 130 negative electrode layer,
140 solid electrolyte layer, 200 alignment jig

Claims (2)

It is a laminated type power storage element in which an electrode body having a sheet-shaped positive electrode and a negative electrode is sealed inside a bag-shaped exterior that is flat in the vertical direction.
The strip-shaped positive electrode and negative electrode terminal plates connected to the positive electrode and the negative electrode, respectively, are derived from a predetermined edge on the peripheral edge of the exterior body.
The exterior body is made of two laminated films in which insulating resin layers are formed on both the front and back surfaces of the base material of the metal foil, and the end face of the metal foil is exposed at the predetermined edge.
The two laminated films are welded to each other in a region that orbits a planar shape while facing each other in the vertical direction, and are welded via a tab film that sandwiches the electrode terminal plate in the vertical direction at the predetermined edge. Being done
The positive electrode and negative electrode terminal plates are derived from a recessed region formed by cutting out a part of the predetermined edge.
The upper surface and the lower surface of the tab film are exposed to the outside at the recess, and the tab film is arranged at the predetermined edge so as to be aligned with the outer shape of the exterior body outside the region where the recess is formed.
A laminated type power storage element characterized by this. The laminated type power storage element according to claim 1, wherein only one sheet-shaped positive electrode and one negative electrode are provided.

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