THIN TYPE STACKED BATTERY

A thin type stacked battery includes battery pack formed by a plurality of stacked unit cells, each formed by positive electrode current collector, positive electrode, electrolyte, negative electrode, and negative electrode current collector stacked in that order, and seal material. The positive electrode current collector of one unit cell, the negative electrode current collector of another unit cell, and the seal material function as an exterior body surrounding a surrounded part. At least one of the positive electrode current collector of one unit cell and the negative electrode current collector of the other unit cell has a metal layer. At least the negative electrode current collector of one unit cell and the positive electrode current collector of the other unit cell have resin layers.

FIELD

The present disclosure relates to a thin type stacked battery.

BACKGROUND

PTL 1 (Japanese Unexamined Patent Publication No. 2020-061300) describes a battery formed by stacking layers of unit cells. In the art described in PLT 1, current collectors of the battery have conductive resin layers so as to lighten the weight of the battery.

If attempting to reduce the thickness in addition to lightening the weight of the battery, for example, a battery case (metal can case) such as described in PTL 1 is liable to make reduction of the thickness of the battery difficult, so a caseless battery is desirable. If the battery described in PLT 1 is made caseless, moisture reaches the electrode bodies through current collectors having conductive resin layers and the battery performance is liable to deteriorate.

SUMMARY

In consideration of the above-mentioned point, the present disclosure has as its object the provision of a thin type stacked battery able to simultaneously satisfy lighter weight, reduced thickness, and moisture permeation resistance.

(1) One aspect of the present disclosure is a thin type stacked battery including: a battery pack formed by a plurality of stacked unit cells, each unit cell being formed by positive electrode current collector, positive electrode, electrolyte, negative electrode, and negative electrode current collector stacked in that order, and a seal material, wherein the positive electrode current collector of a first end unit cell which is the unit cell positioned at one end in the stacking direction among the plurality of stacked unit cells forming the battery pack, wherein the positive electrode current collector of the first end unit cell does not abut against the negative electrode current collector of the unit cell which adjoins the first end unit cell, the negative electrode current collector of a second end unit cell which is the unit cell positioned at the other end in the stacking direction among the plurality of stacked unit cells forming the battery pack, wherein the negative electrode current collector of the second end unit cell does not abut against the positive electrode current collector of the unit cell which adjoins the second end unit cell, and the seal material function as an exterior body surrounding a surrounded part which corresponds to the battery pack except the positive electrode current collector of the first end unit cell and the negative electrode current collector of the second end unit cell, at least one of the positive electrode current collector of the first end unit cell and the negative electrode current collector of the second end unit cell has a metal layer, and at least the negative electrode current collector of the first end unit cell and the positive electrode current collector of the second end unit cell have resin layers.

(2) In the thin type stacked battery of the aspect (1), the electrolyte may be a solid electrolyte.

(3) In the thin type stacked battery of the aspect (1), the negative electrode current collector of the first end unit cell, the positive electrode current collector of the second end unit cell, and the positive electrode current collectors and the negative electrode current collectors of the unit cells other than the first end unit cell and the second end unit cell among the plurality of stacked unit cells forming the battery pack may be embedded in the seal material.

(4) In the thin type stacked battery according to the aspect (1), a thickness of each of the plurality of stacked unit cells may be 0.1 to 2 mm.

(5) In the thin type stacked battery according to the aspect (1), an electrolyte may be included in at least one of the positive electrode and the negative electrode.

(6) In the thin type stacked battery of the aspect (1), the metal layer of the positive electrode current collector of the first end unit cell may be larger than the positive electrode of the first end unit cell, and the metal layer of the negative electrode current collector of the second end unit cell may be larger than the negative electrode of the second end unit cell.

(7) In the thin type stacked battery of the aspect (1), the metal layer of the positive electrode current collector of the first end unit cell and the seal material may be welded, and the metal layer of the negative electrode current collector of the second end unit cell and the seal material may be welded.

(8) In the thin type stacked battery of the aspect (1), the seal material surrounding the positive electrode, the electrolyte, and the negative electrode of the first end unit cell and the seal material surrounding the positive electrode, the electrolyte, and the negative electrode of the unit cell adjoining the first end unit cell may be fused.

(9) In the thin type stacked battery of the aspect (1), the battery pack may include the unit cell which is not either of the first end unit cell and the second end unit cell, and the positive electrode current collector and the negative electrode current collector of the unit cell which is not either of the first end unit cell and the second end unit cell may have resin layers.

(10) In the thin type stacked battery of the aspect (1), the unit cell adjoining the first end unit cell may be the second end unit cell, and the unit cell adjoining the second end unit cell may be the first end unit cell.

(11) In the thin type stacked battery of the aspect (1), one of the positive electrode current collector of the first end unit cell and the negative electrode current collector of the second end unit cell may be a current collector which does not have a metal layer, and the current collector which does not have the metal layer may have a resin layer.

(12) In the thin type stacked battery of the aspect (1), the positive electrode current collector of the first end unit cell and the negative electrode current collector of the second end unit cell may have metal layers.

(13) In the thin type stacked battery of the aspect (12), the positive electrode current collector of the first end unit cell may have a resin layer, and the negative electrode current collector of the second end unit cell may have a resin layer.

(14) In the thin type stacked battery of the aspect (13), the resin layer of the positive electrode current collector of the first end unit cell may abut against the positive electrode of the first end unit cell, and the resin layer of the negative electrode current collector of the second end unit cell may abut against the negative electrode of the second end unit cell.

(15) In the thin type stacked battery of the aspect (12), the positive electrode current collector of the first end unit cell having the metal layer may not have a resin layer, and the negative electrode current collector of the second end unit cell having the metal layer may not have a resin layer.

(16) In the thin type stacked battery of the aspect (15), the metal layer of the positive electrode current collector of the first end unit cell may abut against the positive electrode of the first end unit cell, and the metal layer of the negative electrode current collector of the second end unit cell may abut against the negative electrode of the second end unit cell.

(17) In the thin type stacked battery of the aspect (9), the resin layer of the negative electrode current collector of the first end unit cell may abut against the resin layer of the positive electrode current collector of the unit cell which is not either of the first end unit cell and the second end unit cell, and the resin layer of the negative electrode current collector of the unit cell which is not either of the first end unit cell and the second end unit cell may abut against the resin layer of the positive electrode current collector of the second end unit cell.

According to the present disclosure, it is possible to simultaneously satisfy lighter weight, reduced thickness, and moisture permeation resistance of the thin type stacked battery.

DESCRIPTION OF EMBODIMENTS

Below, referring to the drawings, embodiments of a thin type stacked battery of the present disclosure will be explained.

First Embodiment

FIG.1is a view schematically showing one example of the thin type stacked battery100of a first embodiment.FIG.2is a view schematically showing one example of part of a unit cell10-1(10-2,10-3) forming part of a battery pack10forming part of the thin type stacked battery100of the first embodiment shown inFIG.1.

In the example shown inFIG.1andFIG.2, the thin type stacked battery100is provided with the battery pack10formed by the unit cell10-1, the unit cell10-2, and the unit cell10-3stacked together and with seal materials20-1,20-2, and20-3.

The unit cell10-1is positioned at one end (end of top side ofFIG.1) in the stacking direction (up-down direction ofFIG.1) among the unit cells10-1,10-2, and10-3forming the battery pack10. The unit cell10-1is formed by positive electrode current collector1, positive electrode2, separator3including an electrolyte (for example, the separator3in which the electrolyte is impregnated), negative electrode4, and negative electrode current collector5stacked in that order from above inFIG.1andFIG.2. The positive electrode current collector1of the unit cell10-1has resin layer1A and metal layer1B.

As the resin layer1A of the positive electrode current collector1of the unit cell10-1, it is possible to use any resin current collector functioning as the positive electrode current collector1. That is, the resin layer1A of the positive electrode current collector1of the unit cell10-1is a conductive resin layer. The resin layer1A of the positive electrode current collector1of the unit cell10-1is preferably a light weight current collector using a resin as its base. As the resin layer1A of the positive electrode current collector1of the unit cell10-1, for example, a resin current collector (vinyl resin: VGCF® (vapor grown carbon fiber)=90:10 wt %) is used.

As the metal layer1B of the positive electrode current collector1of the unit cell10-1, it is possible to use any metal material through which moisture does not permeate. As the metal layer1B of the positive electrode current collector1of the unit cell10-1, for example, aluminum foil can be used.

The positive electrode2of the unit cell10-1abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-1.

As a positive electrode material forming the positive electrode2of the unit cell10-1, for example, LiNiCoMn, SE (solid electrolyte) (LiI—LiBr—Li2S—P2S5), VGCF (vapor grown carbon fiber), and SBR (styrene-butadiene rubber) mixed together can be used. Positive electrode active material, conductive assistant, and tackifier (binder) contained in the positive electrode2of the unit cell10-1are not designated.

That is, the positive electrode2of the unit cell10-1may contain the electrolyte. If the positive electrode2of the unit cell10-1contains the electrolyte, the electrolyte is preferably the solid electrolyte with a high heat resistance (sulfide or oxide). This is because the solid electrolyte which is resistant to heat is necessary for heat welding of the seal material20-1etc.

The electrolyte contained in the separator3of the unit cell10-1is preferably the solid electrolyte with the high heat resistance due to the above-mentioned reasons.

As the material forming the separator3of the unit cell10-1, for example, the SE and the SBR mixed together may be used.

The separator3of the unit cell10-1may be substantially formed by a solid electrolyte material. The separator3of the unit cell10-1may, for example, further contain the binder etc. The separator3of the unit cell10-1can contain any solid electrolyte material. The separator3of the unit cell10-1may, for example, contain an Li2S—P2S5-based solid electrolyte etc.

As negative electrode material forming the negative electrode4of the unit cell10-1, for example, graphite, SE (LiI—LiBr—Li2S—P2S5), VGCF, and SBR mixed together can be used. Negative electrode active material, conductive assistant, and tackifier contained in the negative electrode4of the unit cell10-1are not designated.

That is, the negative electrode4of the unit cell10-1may contain the electrolyte. If the negative electrode4of the unit cell10-1contains the electrolyte, due to the above-mentioned reasons, the electrolyte is preferably the solid electrolyte with the high heat resistance.

The negative electrode current collector5of the unit cell10-1has a resin layer5A and does not have a metal layer5B.

The resin layer5A of the negative electrode current collector5of the unit cell10-1abuts against the negative electrode4of the unit cell10-1.

As the resin layer5A of the negative electrode current collector5of the unit cell10-1, it is possible to use any resin current collector functioning as the negative electrode current collector5. That is, the resin layer5A of the negative electrode current collector5of the unit cell10-1is the conductive resin layer. The resin layer5A of the negative electrode current collector5of the unit cell10-1is preferably the light weight current collector using the resin as its base. As the resin layer5A of the negative electrode current collector5of the unit cell10-1, for example, the resin current collector (vinyl resin: VGCF (vapor grown carbon fiber)=90:10 wt %) is used.

The unit cell10-2is positioned at the other end (end of bottom side ofFIG.1) in the stacking direction (up-down direction ofFIG.1) among the three unit cells10-1,10-2, and10-3forming the battery pack10. The unit cell10-2is formed by the positive electrode current collector1, the positive electrode2, the separator3including the electrolyte (for example, the separator3in which the electrolyte is impregnated), the negative electrode4, and the negative electrode current collector5stacked in that order from above inFIG.1andFIG.2.

The positive electrode current collector1of the unit cell10-2has the resin layer1A and does not have the metal layer1B. The resin layer1A of the positive electrode current collector1of the unit cell10-2is formed in the same way as the resin layer1A of the positive electrode current collector1of the unit cell10-1.

The positive electrode2of the unit cell10-2abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-2. The positive electrode2of the unit cell10-2is formed in the same way as the positive electrode2of the unit cell10-1.

The separator3of the unit cell10-2is formed in the same way as the separator3of the unit cell10-1.

The negative electrode4of the unit cell10-2is formed in the same way as the negative electrode4of the unit cell10-1.

The negative electrode current collector5of the unit cell10-2has the resin layer5A and the metal layer5B.

The resin layer5A of the negative electrode current collector5of the unit cell10-2abuts against the negative electrode4of the unit cell10-2. The resin layer5A of the negative electrode current collector5of the unit cell10-2is formed in the same way as the resin layer5A of the negative electrode current collector5of the unit cell10-1.

As the metal layer5B of the negative electrode current collector5of the unit cell10-2, it is possible to use any metal material through which moisture does not permeate. As the metal layer5B of the negative electrode current collector5of the unit cell10-2, for example, copper foil or nickel foil can be used.

In the example shown inFIG.1andFIG.2, the positive electrode current collector1of the unit cell10-1has the metal layer1B and the negative electrode current collector5of the unit cell10-2has the metal layer5B, but in another example, the positive electrode current collector1of the unit cell10-1may have the metal layer1B and the negative electrode current collector5of the unit cell10-2may not have the metal layer5B. That is, in this example, the negative electrode current collector5of the unit cell10-2is a current collector which does not have the metal layer5B, while the negative electrode current collector5of the unit cell10-2not having the metal layer5B has the resin layer5A.

In still another example, the positive electrode current collector1of the unit cell10-1may not have the metal layer1B while the negative electrode current collector5of the unit cell10-2may have the metal layer5B. That is, in this example, the positive electrode current collector1of the unit cell10-1is a current collector which does not have the metal layer1B while the positive electrode current collector1of the unit cell10-1not having the metal layer1B has the resin layer1A.

In the example shown inFIG.1andFIG.2, the unit cell10-3is positioned in the middle of the stacking direction (up-down direction ofFIG.1) among the three unit cells10-1,10-2, and10-3forming the battery pack10. That is, the unit cell10-3is arranged adjoining the unit cell10-1and adjoining the unit cell10-2. The unit cell10-3is formed by the positive electrode current collector1, the positive electrode2, the separator3including the electrolyte (for example, the separator3in which the electrolyte is impregnated), the negative electrode4, and the negative electrode current collector5stacked in that order from above inFIG.1andFIG.2.

The positive electrode current collector1of the unit cell10-3has the resin layer1A and does not have the metal layer1B. The resin layer1A of the positive electrode current collector1of the unit cell10-3abuts against the resin layer5A of the negative electrode current collector5of the unit cell10-1. That is, the resin layer5A of the negative electrode current collector5of the unit cell10-1abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-3which is neither the unit cell10-1nor the unit cell10-2. The resin layer1A of the positive electrode current collector1of the unit cell10-3is formed in the same way as the resin layer1A of the positive electrode current collector1of the unit cell10-1.

The positive electrode2of the unit cell10-3abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-3. The positive electrode2of the unit cell10-3is formed in the same way as the positive electrode2of the unit cell10-1.

The separator3of the unit cell10-3is formed in the same way as the separator3of the unit cell10-1.

The negative electrode4of the unit cell10-3is formed in the same way as the negative electrode4of the unit cell10-1.

The negative electrode current collector5of the unit cell10-3has the resin layer5A but does not have the metal layer5B. The resin layer5A of the negative electrode current collector5of the unit cell10-3abuts against the negative electrode4of the unit cell10-3. Further, the resin layer5A of the negative electrode current collector5of the unit cell10-3abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-2. That is, the resin layer5A of the negative electrode current collector5of the unit cell10-3which is neither the unit cell10-1nor the unit cell10-2abuts against the resin layer1A of the positive electrode current collector1of the unit cell10-2. The resin layer5A of the negative electrode current collector5of the unit cell10-3is formed in the same way as the resin layer5A of the negative electrode current collector5of the unit cell10-1.

In the example shown inFIG.1andFIG.2, a thickness of each of the unit cells10-1,10-2, and10-3is 0.1 to 2 mm.

In the example shown inFIG.1andFIG.2, the battery pack10is formed by stacking three unit cells10-1,10-2, and10-3, but in other examples, the battery pack10may be formed by stacking any number greater than or equal to 4 of unit cells10-1,10-2,10-3, . . . .

In the example shown inFIG.1andFIG.2, the seal material20-1has the function of scaling the unit cell10-1. In more detail, the seal material20-1has the function of leaving only the metal layer1B of the positive electrode current collector1of the unit cell10-1exposed and covering and sealing the remaining parts of the unit cell10-1. That is, the seal material20-1surrounds the positive electrode2, the separator3including the electrolyte, and the negative electrode4of the unit cell10-1. As the seal material20-1, it is possible to use any resin material having the function of covering and scaling the remaining parts of the unit cell10-1. As the seal material20-1, for example, PP (polypropylene) film can be used.

The seal material20-2has the function of sealing the unit cell10-2. In more detail, the seal material20-2has the function of leaving only the metal layer5B of the negative electrode current collector5of the unit cell10-2exposed and covering and sealing the remaining parts of the unit cell10-2. That is, the seal material20-2surrounds the positive electrode2, the separator3including the electrolyte, and the negative electrode4of the unit cell10-2. As the seal material20-2, it is possible to use the resin material similar to the seal material20-1.

The seal material20-3has the function of covering and sealing the unit cell10-3. That is, the seal material20-3surrounds the positive electrode2, the separator3including the electrolyte, and the negative electrode4of the unit cell10-3. Further, the seal material20-3and the seal material20-1are fused and the seal material20-3and the seal material20-2are fused. For this reason, the unit cells10-1,10-2, and10-3can be fixed by the seal materials20-1,20-2, and20-3. Further, it is possible to keep down the liability of water invading the battery pack10through the clearance between the seal material20-1and the seal material20-3and the liability of water invading the battery pack10through the clearance between the seal material20-2and the seal material20-3. As the seal material20-3, it is possible to use the resin material similar to the seal material20-1.

That is, the seal materials20-1,20-2, and20-3have the function of leaving the metal layer1B of the positive electrode current collector1of the unit cell10-1and the metal layer5B of the negative electrode current collector5of the unit cell10-2exposed and covering and sealing the remaining parts of the battery pack10.

That is, in the example shown inFIG.1andFIG.2, the positive electrode current collector1of the unit cell10-1, the negative electrode current collector5of the unit cell10-2, and the seal materials20-1,20-2, and20-3function as an exterior body surrounding a surrounded part which corresponds to the battery pack10except the positive electrode current collector1of the unit cell10-1and the negative electrode current collector5of the unit cell10-2. In other words, the negative electrode current collector5of the unit cell10-1, the positive electrode current collector1of the unit cell10-2, and the positive electrode current collector1and negative electrode current collector5of the unit cell10-3other than the unit cell10-1and unit cell10-2among the unit cells10-1,10-2, and10-3forming the battery pack10are embedded in the seal materials20-1,20-2, and20-3. For this reason, it is possible to suppress short circuit between the positive electrode current collectors1and the negative electrode current collectors5of the unit cells10-1,10-2, and10-3.

Further, in the example shown inFIG.1andFIG.2, as explained above, the positive electrode current collector1of the unit cell10-1has the metal layer1B and the negative electrode current collector5of the unit cell10-2has the metal layer5B.

Furthermore, in the example shown inFIG.1andFIG.2, as explained above, the positive electrode current collector1of the unit cell10-1has the resin layer1A and the negative electrode current collector5of the unit cell10-1has the resin layer5A, the positive electrode current collector1of the unit cell10-2has the resin layer1A and the negative electrode current collector5of the unit cell10-2has the resin layer5A, and the positive electrode current collector1of the unit cell10-3has the resin layer1A and the negative electrode current collector5of the unit cell10-3has the resin layer5A.

In another example, the positive electrode current collector1of the unit cell10-1having the metal layer1B may not have the resin layer1A and the negative electrode current collector5of the unit cell10-2having the metal layer5B may not have the resin layer5A. In this example, the metal layer1B of the positive electrode current collector1of the unit cell10-1abuts against the positive electrode2of the unit cell10-1and the metal layer5B of the negative electrode current collector5of the unit cell10-2abuts against the negative electrode4of the unit cell10-2.

In more detail, in the example shown inFIG.1andFIG.2, (left-right direction dimension ofFIG.1of) the metal layer1B of the positive electrode current collector1of the unit cell10-1is larger than (left-right direction dimension ofFIG.1of) the positive electrode2of the unit cell10-1. Further, the metal layer1B of the positive electrode current collector1of the unit cell10-1and the seal material20-1are welded. For this reason, permeation of moisture to the positive electrode2of the unit cell10-1can be suppressed by the metal layer1B of the positive electrode current collector1of the unit cell10-2and the seal material20-1.

Furthermore, (left-right direction dimension ofFIG.1of) the metal layer5B of the negative electrode current collector5of the unit cell10-2is larger than (left-right direction dimension ofFIG.1of) the negative electrode4of the unit cell10-2. Further, the metal layer5B of the negative electrode current collector5of the unit cell10-2and the seal material20-2are welded. For this reason, permeation of moisture to the negative electrode4of the unit cell10-2can be suppressed by the metal layer5B of the negative electrode current collector5of the unit cell10-2and the seal material20-2.

In the thin type stacked battery100of the first embodiment, it is possible to simultaneously satisfy lighter weight, reduced thickness, and moisture permeation resistance.

Second Embodiment

Below, a second embodiment of the thin type stacked battery of the present disclosure will be explained. The thin type stacked battery100of the second embodiment is formed in the same way as the above-mentioned thin type stacked battery100of the first embodiment except for the points explained below.

FIG.3is a view schematically showing one example of the thin type stacked battery100of the second embodiment.

In the example shown inFIG.3, the thin type stacked battery100is provided with the battery pack10formed by the unit cell10-1and the unit cell10-2stacked together and with the seal materials20-1and20-2.

The unit cell10-1is positioned at one end (end of top side ofFIG.3) in the stacking direction (up-down direction ofFIG.3) among the two unit cells10-1and10-2forming the battery pack10. The unit cell10-1is formed in the same way as the unit cell10-1of the thin type stacked battery100of the first embodiment.

The unit cell10-2is positioned at the other end (end of bottom side ofFIG.3) in the stacking direction (up-down direction ofFIG.3) of the two unit cells10-1and10-2forming the battery pack10. The unit cell10-2is arranged adjoining the unit cell10-1and is formed in the same way as the unit cell10-2of the thin type stacked battery100of the first embodiment.

In the example shown inFIG.3, unlike the example shown inFIG.1andFIG.2, the resin layer1A of the positive electrode current collector1of the unit cell10-2abuts against the resin layer5A of the negative electrode current collector5of the unit cell10-1.

Further, in the example shown inFIG.3, the seal material20-1and the seal material20-2are fused together and the unit cells10-1,10-2are fixed by the seal materials20-1and20-2. The seal materials20-1and20-2leave the metal layer1B of the positive electrode current collector1of the unit cell10-1and the metal layer5B of the negative electrode current collector5of the unit cell10-2exposed and cover and seal the remaining parts of the battery pack10.

In the example shown inFIG.3, the positive electrode current collector1of the unit cell10-1, the negative electrode current collector5of the unit cell10-2, and the seal materials20-1and20-2function as the exterior body surrounding the surrounded part which corresponds to the battery pack10except the positive electrode current collector1of the unit cell10-1and the negative electrode current collector5of the unit cell10-2, and the negative electrode current collector5of the unit cell10-1and the positive electrode current collector1of the unit cell10-2are embedded in the seal materials20-1and20-2.

FIG.4AtoFIG.4DandFIG.5AtoFIG.5Care views for explaining one example of the process of production of part of the unit cell10-1(10-2) forming part of the thin type stacked battery100of the second embodiment.FIG.6AandFIG.6Bare views for explaining one example of the process of production the thin type stacked battery100of the second embodiment.

In the example shown inFIG.4AtoFIG.6B, to produce the unit cell10-1(10-2), first, as shown inFIG.4A, for example, using a solvent such as butyl lactate etc., the negative electrode material is made to disperse and is coated on release paper RP1whereby the negative electrode4with the release paper RP1attached is prepared.

As the solvent, one other than butyl lactate may be used, but heptane, butyl lactate, etc. which are resistant to reacting with the SE are preferable.

While not shown inFIG.4A, for example, using the solvent such as the butyl lactate etc., the positive electrode material is made to disperse and is coated on release paper RP3(seeFIG.4D) whereby the positive electrode2(seeFIG.4D) with the release paper RP3attached is prepared. Further, for example, using the solvent such as the butyl lactate etc., separator material is made to disperse and is coated on release paper RP2(seeFIG.4B) whereby the separator3(seeFIG.4B) with the release paper RP2attached is prepared.

Next, the positive electrode2with the release paper RP3attached is cut out (seeFIG.4D). Further, as shown inFIG.4B, the negative electrode4with the release paper RP1attached is cut out and the separator3with the release paper RP2attached is cut out. The shapes of the cut out positive electrode2with the release paper RP3attached, the cut out negative electrode4with the release paper RP1attached, and the cut out separator3with the release paper RP2attached may be square, circular or polygonal. The positive electrode2is preferably smaller than the negative electrode4.

Next, as shown inFIG.4BandFIG.4C, the negative electrode4and the separator3are made to face each other and are monoaxially pressed (for example, 392 MPa, 1 min). To raise the adhesion of the solid electrolyte, a pressure of 100 MPa or more is preferable.

Next, as shown inFIG.4C, the release paper RP1of the negative electrode4is removed and the release paper RP2of the separator3is removed.

Next, as shown inFIG.4C, the positive electrode2is made to face the separator3and is pressed by hydrostatic pressing (CIP: Cold Isostatic Pressing) (for example, 392 MPa, 1 min). A pressing method other than the hydrostatic pressing may be used. The hydrostatic pressing is preferable from the viewpoint of suppressing short-circuits.

Next, as shown inFIG.4DandFIG.5A, the release paper RP3of the positive electrode2is removed and an electrode (the positive electrode2, the separator3, and the negative electrode4) is prepared.

Next, as shown inFIG.5BandFIG.5C, (the resin layer1A of) the positive electrode current collector1, the seal material20-1(20-2), the electrode (the positive electrode2, the separator3, and the negative electrode4), and (the resin layer5A of) the negative electrode current collector5are stacked and the assembly is heated in a vacuum state (for example, 160° C. and 1 min), whereby the unit cell10-1(10-2) is prepared. The external dimension of the seal material20-1(20-2) is preferably larger than the external dimension of (the resin layer1A) of the positive electrode current collector1and the external dimension of (the resin layer5A) of the negative electrode current collector5. From the viewpoint of the air seal, the heating is preferably performed in a vacuum state. The heating temperature depends on the seal material20-1(20-2). At the time of preparation of the prototype shown in the later explainedFIG.7AandFIG.7B, as the seal material20-1(20-2), a seal material (PP) made by Dai Nippon Printing Co., Ltd. was used.

Next, as shown inFIG.6A, the unit cell10-1and the unit cell10-2are stacked and the aluminum foil functioning as the metal layer1B of the positive electrode current collector1of the unit cell10-1and the copper foil or the nickel foil functioning as the metal layer5B of the negative electrode current collector5of the unit cell10-2are arranged.

Next, as shown inFIG.6AandFIG.6B, the assembly is heated in the vacuum state (for example, 160° C. for 1 min) whereby a stacked body (the thin type stacked battery100of the second embodiment) is prepared.

FIG.7AandFIG.7Bare photos of prototypes of the thin type stacked battery100of the second embodiment shown inFIG.3. In more detail,FIG.7Ashows the thickness of the prototype of the thin type stacked battery100of the second embodiment, whileFIG.7Bshows the voltage of the prototype of the thin type stacked battery100of the second embodiment.

In the thin type stacked battery100of the second embodiment as well, it is possible to simultaneously satisfy lighter weight, reduced thickness, and moisture permeation resistance.

In this way, embodiments of the thin type stacked battery of the present disclosure were explained with reference to the drawings, but the thin type stacked battery of the present disclosure is not limited to the above-mentioned embodiments and can be suitably changed within a range not deviating from the gist of the present disclosure. The constitutions of the examples of the above-mentioned embodiments may be suitably combined.