WO2018166882A1

WO2018166882A1 - Bag-packed positive electrode plate, layered electrode assembly, energy storage device, and manufacturing method of bag-packed positive electrode plate

Info

Publication number: WO2018166882A1
Application number: PCT/EP2018/055738
Authority: WO
Inventors: Kazuya Okabe; Yusuke Oki; Yasuaki YAMAMURA
Original assignee: Lithium Energy and Power GmbH and Co KG
Current assignee: Lithium Energy and Power GmbH and Co KG
Priority date: 2017-03-13
Filing date: 2018-03-08
Publication date: 2018-09-20
Anticipated expiration: 2019-09-13
Also published as: JP2018152226A

Abstract

A bag-packed positive electrode plate according to an aspect of the present invention includes: a positive electrode plate; and a pair of separators which sandwiches the positive electrode plate therebetween, wherein the separator has a resin layer, a heat resistant layer which is stacked on the resin layer, and an adhesive layer which is stacked on a surface of the heat resistant layer which opposedly faces the positive electrode plate, and the adhesive layers of the pair of separators are adhered to the positive electrode plate and are adhered to each other outside the positive electrode plate as viewed in a plan view.

Description

DESCRIPTION

TITLE OF THE INVENTION: BAG-PACKED POSITIVE ELECTRODE PLATE, LAYERED ELECTRODE ASSEMBLY, ENERGY STORAGE DEVICE, AND MANUFACTURING METHOD OF BAG-PACKED POSITIVE ELECTRODE PLATE

TECHNICAL FIELD

[0001]

The present invention relates to a bag-packed positive electrode plate, a layered electrode assembly, an energy storage device, and a manufacturing method of a bag-packed positive electrode plate.

BACKGROUND ART

[0002]

A chargeable and dischargeable energy storage device has been used in various equipment such as a mobile phone or an electric vehicle.

Recently, along with a realization of higher output and higher performance of these equipment, an energy storage device which is smaller in size and having a larger electric capacitance (larger energy density) has been requested.

[0003]

In general, the energy storage device includes a layered electrode assembly which is formed by alternately stacking a positive electrode plate having a surface on which a positive active material layer is formed and a negative electrode plate having a surface on which a negative active material layer is formed with a separator having electric insulation property sandwiched between the positive electrode plate and the negative electrode plate. To increase an electric capacitance per unit volume in such an energy storage device, it is effective to reduce a thickness of the separator. To satisfy such a request, an energy storage device where a separator is formed of a resin film has been put into practice.

[0004]

In an energy storage device, there is a possibility that metal precipitation (lithium dendrite, for example) which is formed on a negative electrode by electrodeposition penetrates a separator thus causing minute short-circuiting between a positive electrode plate and a negative electrode plate. To eliminate such a possibility, there has been known a layered electrode assembly which can suppress mixing of metal species which generate metal ions capable of forming a precipitation on an electrolyte in the vicinity of the positive electrode plate and can suppress

electrodeposition caused by contacting of metal ions with a negative electrode using a bag-packed electrode plate which is formed into a bag shape by welding outer peripheries of a pair of separators which sandwiches the positive electrode plate or the negative electrode plate therebetween to each other.

[0005]

A welded portion of the separators does not contribute to charging and discharging and hence, when a space in the inside of an energy storage device is occupied only by the welded portion of the separators, there may be a possibility that such a configuration obstructs the increase of energy density of the energy storage device. In the energy storage device, when the positive electrode plate projects from the negative electrode plate as viewed in a plan view, an electric current is concentrated on an end portion of the negative electrode plate so that electrodeposition is locally accelerated and hence, it is preferable that the positive electrode plate be disposed so as not to project from the negative electrode plate as viewed in a plan view. Accordingly, by using a layered electrode assembly formed by stacking a bag-packed positive electrode plate and a negative electrode plate which is not bag-packed, the space efficiency can be enhanced thus increasing energy density of the energy storage device.

[0006]

The separator formed of a resin film is relatively weak to heat.

Accordingly, when energy density of an energy storage device is increased, there is a possibility that the separator is damaged by heat or metal precipitation which is generated by electrodeposition penetrates the separator thus forming minute short-circuiting between the positive electrode plate and the negative electrode plate. Accordingly, there has been proposed an energy storage device where a heat resistant layer

(inorganic layer) is formed on a surface of a separator which is brought into contact with a plate thus enhancing heat resistance of the separator (see JP- A-2013-143337).

[0007]

In the energy storage device described in the above-mentioned JP-A- 2013-143337, a layered electrode assembly is formed by alternately stacking a bag-packed positive electrode plate where a positive electrode plate is sandwiched between a pair of separators and the pair of separators is adhered to each other outside the positive electrode plate as viewed in a plan view, and a negative electrode plate which has a size larger than the positive electrode plate and smaller than the separators and is not bag- packed, and the layered electrode assembly is accommodated in the inside of an outer case.

PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0008]

Patent Document l: JP-A-2013- 143337

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0009]

The bag-packed positive electrode plate described in the above- mentioned JP-A-2013- 143337 uses separators each having a heat resistant layer on a surface thereof which is brought into contact with an electrode plate. Accordingly, the pair of separators are joined to each other outside the positive electrode plate as viewed in a plan view by breaking the heat resistant layers and by welding resin films to each other using a jig

(ultrasonic welding horn) having a convex-shaped contact surface. The bag-packed positive electrode plate described in JP-A-2013- 143337 requires the above-mentioned joining method and hence, the pair of separators is discontinuously joined to each other outside the positive electrode plate as viewed in a plan view and hence, there is a possibility that foreign

substances which generate metal ions enter between the positive electrode plate and the separator from non-joined portions. [0010]

It is an object of the present invention to provide a bag-packed positive electrode plate, a layered electrode assembly, an energy storage device, and a manufacturing method of a bag-packed positive electrode plate which can prevent entrance of foreign substances between a positive electrode plate and a separator.

MEANS FOR SOLVING THE PROBLEMS

[0011]

A bag-packed positive electrode plate according to one aspect of the present invention includes^: a positive electrode plate! and a pair of separators which sandwiches the positive electrode plate therebetween, wherein each of the separators has a resin layer, a heat resistant layer which is stacked on the resin layer, and an adhesive layer which is stacked on a surface of the heat resistant layer which opposedly faces the positive electrode plate, and the adhesive layers of the pair of separators are adhered to the positive electrode plate and are adhered to each other outside the positive electrode plate as viewed in a plan view.

[0012]

A manufacturing method of a bag-packed positive electrode plate according to another aspect of the present invention includes^: sandwiching a positive electrode plate by a pair of separators each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and sandwiching a layered product of the positive electrode plate and the pair of separators using a heating mold heated at a temperature lower than a melting point of the resin layer thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.

[0013]

A manufacturing method of a bag-packed positive electrode plate according to still another aspect of the present invention includes^:

sandwiching a positive electrode plate by a pair of separators each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and sandwiching a layered product of the positive electrode plate and the pair of separators by a pair of molds in which at least one of the mold is ultrasonically vibrated thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.

ADVANTAGES OF THE INVENTION

[0014]

In the bag-packed positive electrode plate according to one aspect of the present invention and the bag-packed positive electrode plate obtained by the manufacturing method of a bag-packed positive electrode plate according to another aspect of the present invention, the adhesive layers of the pair of separators are adhered to the positive electrode plate and, at the same time, the adhesive layers of the pair of separators are adhered to each other outside the positive electrode plate as viewed in a plan view and hence, it is possible to prevent mixing of foreign substances between the positive electrode plate and the separator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]

Fig. 1 is a schematic exploded perspective view showing a

configuration of an energy storage device according to one embodiment of the present invention.

Fig. 2 is a schematic cross- sectional view of a bag-packed positive electrode plate of the energy storage device shown in Fig. 1.

Fig. 3 is a schematic plan view of the bag-packed positive electrode plate shown in Fig. 2.

MODE FOR CARRYING OUT THE INVENTION

[0016]

[0017] In the bag-packed positive electrode plate, the adhesive layers of the pair of separators are adhered to the positive electrode plate and hence, it is possible to prevent mixing of foreign substances between the positive electrode plate and the separators. Further, the adhesive layers are adhered to each other outside the positive electrode plate as viewed in a plan view and hence, it is possible to prevent mixing of foreign substances into an end surface side of the positive electrode plate, and it is also possible to prevent peeling of the separator from the positive electrode plate.

Accordingly, mixing of foreign substances can be prevented with more certainty. Further, when the separators are exposed to a high temperature environment in a peculiar situation which is not predictable in a normal in- use state, it is possible to prevent the occurrence of a phenomenon that the separator shrinks so that the positive electrode plate is exposed from the separator.

[0018]

It is preferable that the adhesive layer be not partially adhered to the positive electrode plate and the other adhesive layer which the adhesive layer opposedly faces. With such a configuration, an electrolyte solution can be supplied through a non-adhered portion between the positive electrode plate and the separator and hence, pouring of an electrolyte solution into the separator can be facilitated.

[0019]

It is preferable that the adhesive layer be formed of a mixed material which contains^: particles including an electrolyte solution and exhibiting ion conductivity! and a binder. With such a configuration, ion conductivity of the adhesive layer can be relatively increased and hence, an output of the energy storage device can be increased.

[0020]

The layered electrode assembly according to one aspect of the present invention includes a plurality of the bag-packed positive electrode plates and a plurality of negative electrode plates, wherein the bag-packed positive electrode and the negative electrode plates are alternately stacked with each other. The layered electrode assembly includes the bag-packed positive electrode plate which can prevent mixing of foreign substances between the positive electrode plate and the separator and hence, the electrodeposition can be suppressed.

[0021]

The energy storage device according to one aspect of the present invention includes^: the above-mentioned layered electrode assembly! and an outer case which accommodates the layered electrode assembly therein. The energy storage device includes the above-mentioned layered electrode assembly which can suppress the electrodeposition and hence, the energy storage device has high reliability. Further, when a temperature in the energy storage device is increased so that the separator is exposed to a high temperature in a peculiar situation which is not predictable in a normal in- use state, it is possible to prevent the occurrence of a phenomenon that the separator shrinks so that the positive electrode plate is exposed from the separator.

[0022]

A manufacturing method of a bag-packed positive electrode plate according to one aspect of the present invention includes^: sandwiching a positive electrode plate by a pair of separators each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and sandwiching a layered product of the positive electrode plate and the pair of separators using a heating mold heated at a temperature lower than a melting point of the resin layer thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.

[0023]

In the manufacturing method of a bag-packed positive electrode plate, the pair of separators each having the resin layer, the heat resistant layer, and the adhesive layer are sandwiched by a heating mold which is heated at a temperature lower than a melting point of the resin layer so that the adhesive layers are adhered to the positive electrode plate and, at the same time, the opposedly facing adhesive layers are adhered to each other outside the positive electrode plate as viewed in a plan. Accordingly, it is possible to obtain a bag-packed positive electrode plate which can effectively prevent mixing of foreign substances between the positive electrode plate and the separators.

[0024]

A manufacturing method of a bag-packed positive electrode plate according to another aspect of the present invention includes^: sandwiching a positive electrode plate by a pair of separators each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and sandwiching a layered product of the positive electrode plate and the pair of separators by a pair of heating molds in which at least one of the heating mold is ultrasonically vibrated thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.

[0025]

According to the manufacturing method of a bag-packed positive electrode plate, the adhesive layer of the separator can be adhered to the positive electrode plate and the adhesive layer of the opposedly facing separator in a relatively short time. Accordingly, manufacturing efficiency can be enhanced thus realizing the reduction of a manufacturing cost of the bag-packed positive electrode plate.

[0026]

Hereinafter, an embodiment of the present invention is described in detail with reference to drawings suitably.

[0027]

Fig. 1 shows an energy storage device according to one embodiment of the present invention. The energy storage device includes a layered electrode assembly 1, and an outer case 2 which accommodates the layered electrode assembly 1 therein. An electrolyte (an electrolyte solution) is filled in the outer case 2. The energy storage device further includes a positive electrode terminal 3 and a negative electrode terminal 4 which project from the outer case 2, are exposed to an outer surface of the outer case 2, and are electrically connected to the layered electrode assembly 1 in the inside of the outer case 2.

[0028]

The layered electrode assembly 1 includes a plurality of bag-packed positive electrode plates 5 and a plurality of negative electrode plates 6, wherein the bag-packed positive electrode plate 5 and the negative electrode plate 6 are alternately stacked with each other.

[0029]

As shown in Fig. 2, each bag-packed positive electrode plate 5 includes a positive electrode plate 7, and a pair of separators 8 which sandwiches the positive electrode plate 7 therebetween. The pair of separators 8 may be two sheets opposedly facing each other, or may be formed by folding one sheet in two.

[0030]

It is preferable that a width of the bag-packed positive electrode plate 5 be set equal to or below a width of the negative electrode plate 6. To be more specific, in the bag-packed positive electrode plate 5, a width of the separator 8 having an approximately rectangular planar shape is set equal to or below a width of the negative electrode plate 6 having an

approximately rectangular planar shape. In such a layered electrode assembly 1, a whole surface of the positive electrode plate 7 held inside the separator 8 as viewed in a plan view opposedly faces the negative electrode plate 6 without projecting from the negative electrode plate 6 as viewed in a plan view. That is, the positive electrode plate 7 is included in a projection region of the negative electrode plate 6. Accordingly, in the layered electrode assembly 1 and the energy storage device, there is no possibility that a current density is increased on an outer peripheral portion of the negative electrode plate 6 so that electrodeposition is locally accelerated and hence, short-circuiting due to the electrodeposition can be prevented.

[0031]

A lower limit of the difference between a width of the bag-packed positive electrode plate 5 and a width of the negative electrode plate 6 (a value obtained by subtracting the width of the bag-packed positive electrode plate 5 from the width of the negative electrode plate 6) is preferably set to 0 mm, and an upper limit of the difference between the width of the bag- packed positive electrode plate 5 and the width of the negative electrode plate 6 is preferably set to 1 mm, and more preferably set to 0.5 mm. By setting the difference between the width of the bag-packed positive electrode plate 5 and the width of the negative electrode plate 6 to the above- mentioned lower limit or above, the bag-packed positive electrode plate 5 and the negative electrode plate 6 can be easily stacked to each other such that the positive electrode plate 7 does not project from the negative electrode plate 6. Further, by setting the difference between the width of the bag-packed positive electrode plate 5 and the width of the negative electrode plate 6 to the above-mentioned upper limit or below, it is possible to prevent the difference in area between the positive electrode plate 7 and the negative electrode plate 6 from increasing unnecessarily thus increasing energy density of the layered electrode assembly 1 and energy density of the energy storage device.

[0032]

In the layered electrode assembly 1, by positioning the separator 8 of the bag-packed positive electrode plate 5 with respect to the negative electrode plate 6, the positive electrode plate 7 can be relatively easily positioned with respect to the negative electrode plate 6. Accordingly, in the layered electrode assembly 1, even when a ratio of an area of the positive electrode plate 7 with respect to an area of the negative electrode plate 6 is relatively increased, electrodeposition on the outer edge portion of the negative electrode plate 6 is not accelerated and hence, energy density can be relatively increased.

[0033]

The positive electrode plate 7 includes^ a foil-like or sheet-like positive electrode current collector 9 having conductivity! and a positive active material layer 10 which is stacked on a surface of the positive electrode current collector 9. To be more specific, the positive electrode plate 7 includes^ an active material region having a rectangular shape as viewed in a plan view where the positive active material layer 10 is stacked on a surface of the positive electrode current collector 9! and a positive electrode tab 11 which extends from the active material region in a strip shape having a width smaller than a width of the active material region and is connected to the positive electrode terminal 3.

[0034]

As a material for forming the positive electrode current collector 9, a metal material such as aluminum, copper, iron or nickel, or an alloy of such metal materials is used. Among these metal materials, from a viewpoint of taking a balance between a level of conductivity and a cost, aluminum, an aluminum alloy, copper, and a copper alloy are preferably used, and aluminum and an aluminum alloy are more preferably used. Further, as the shape of the positive electrode current collector 9, a foil, a vapor deposition film and the like can be named. From a viewpoint of a cost, the positive electrode current collector 9 is preferably formed of a foil. That is, the positive current collector preferably made of an aluminum foil. As aluminum or an aluminum alloy, A1085P, A3003P prescribed in JIS-H4000 (2014) or the like can be exemplified.

[0035]

A lower limit of an average thickness of the positive electrode current collector 9 is preferably set to 5 μηι, and more preferably set to 10 μηι. On the other hand, an upper limit of the average thickness of the positive electrode current collector 9 is preferably set to 50 μηι, and more preferably set to 40 μηι. By setting the average thickness of the positive electrode current collector 9 to the above-mentioned lower limit or above, the positive electrode current collector 9 can acquire a sufficient strength. Further, by setting the average thickness of the positive electrode current collector 9 to the above-mentioned upper limit or below, energy density of the energy storage device can be increased.

[0036]

The positive active material layer 10 is made of a so-called positive electrode mixture containing a positive active material. The positive electrode mixture which forms the positive active material layer 10 contains arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like when necessary.

[0037]

As the positive active material, for example, a composite oxide expressed by Li_xMO_y (M indicating at least one kind of transition metal) (Li_xCo0₂, Li_xNi0₂, Li_xMn₂0₄, Li_xMn0₃, LixNi_aCo(i-a)0₂, Li_xNi_aMn_pCo(i-_a-_P)0₂, Li_xNi_aMn(₂-_a)O₄ or the like), or a polyanion compound expressed by

LiwMe_x(XOy)_z (Me indicating at least one kind of transition metal, X being P, Si, B, V or the like, for example) (LiFeP0₄, LiMnP0₄, LiNiP0₄, LiCoP0₄, Li3V₂(P0₄)3, Li₂MnSi0₄, Li₂CoP0₄F or the like) can be named. An element or a polyanion in these compounds may be partially replaced with other element or other anion species. In the positive active material layer 10, one kind of these compounds may be used singly or may be used in a state where two or more kinds of compounds are mixed into a compound.

Further, it is preferable that the crystal structure of the positive active material be a layered structure or a spinel structure.

[0038]

A lower limit of a content of the positive active material in the positive active material layer 10 is preferably set to 50 mass%, and more preferably set to 70 mass%, and still further preferably set to 80 mass%. On the other hand, an upper limit of the content of the positive active material in the positive active material layer 10 is preferably set to 99 mass%, and more preferably set to 94 mass%. By setting the content of the positive active material particles within the above-mentioned range, energy density of the energy storage device can be increased.

[0039]

The conductive agent is not particularly limited provided that the conductive agent is made of a conductive material which does not adversely affect battery performance. As such a conductive agent, natural or artificial graphite, carbon black such as furnace black, acetylene black and Ketjen black, metal, conductive ceramics and the like can be named. As the shape of the conductive agent, a powdery form, a fibrous form and the like can be named.

[0040]

A lower limit of a content of the conductive agent in the positive active material layer 10 is preferably set to 0.1 mass%, and more preferably set to 0.5 mass%. On the other hand, as an upper limit of the content of the conductive agent is preferably set to 10mass%, and more preferably set to 5 mass%. By setting the content of the conductive agent within the above-mentioned range, energy density of the energy storage device can be increased.

[0041]

As a material of the binder, for example, a fluororesin

(polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and the like), a thermoplastic resin such as polyethylene, polypropylene and polyimide, elastomer such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber and the like, for example, polysaccharide polymer and the like can be named.

[0042] A lower limit of a content of the binder in the positive active material layer 10 is preferably set to 1 mass%, and more preferably set to 2 mass%. On the other hand, an upper limit of the content of the binder is preferably set to 10 mass%, and more preferably set to 5 mass%. By setting the content of the binder within the above-mentioned range, the positive active material can be held in a stable manner.

[0043]

As a material of the thickening agent, polysaccharide polymer such as carboxymethyl cellulose (CMC), methyl cellulose and the like can be named. Further, when the thickening agent has a functional group reactable with lithium, it is preferable to preliminarily deactivate the functional group by methylation or the like.

[0044]

A material of the filler is not particularly limited provided that the battery performance is not adversely affected by the material. As a main component of the filler, a polyolefin such as polypropylene and polyethylene, silica, alumina, zeolite, glass, carbon and the like can be named.

[0045]

A lower limit of an average thickness of the positive active material layer 10 is preferably set to 10 μηι, and more preferably set to 20 μηι. On the other hand, an upper limit of the average thickness of the positive active material layer 10 is preferably set to 100 μηι, and more preferably set to 80 μηι. By setting the average thickness of the positive active material layer 10 to the above-mentioned lower limit or above, the reaction at the positive electrode can be sufficiently activated. Further, by setting the average thickness of the positive active material layer 10 to the above-mentioned upper limit or below, energy density of the energy storage device can be increased.

[0046]

The separator 8 includes a sheet-like resin layer 12, a heat resistant layer 13 which is stacked on a surface of the resin layer 12 which opposedly faces the positive electrode plate 7, and an adhesive layer 14 which is stacked on a surface of the heat resistant layer 13 which opposedly faces the positive electrode plate 7.

[0047]

As shown in Fig. 3, in the bag-packed positive electrode plate 5, the adhesive layers 14 of the pair of separators 8 are respectively adhered to the positive electrode plate 7, and are adhered to each other outside the positive electrode plate 7 as viewed in a plan view (the adhered portion being indicated by hatching in Fig. 3).

[0048]

The adhesive layer 14 may be adhered to the whole surface of the positive active material layer 10 of the positive electrode plate 7 and the whole projecting region of an adhesive layer of the opposedly facing separator 8 projecting from the positive electrode plate 7. However, it is preferable that the adhesive layer 14 be not partially adhered to the positive electrode plate 7 and the adhesive layer 14 of the opposedly facing separator 8. That is, it is preferable that the adhesive layer 14 be partially adhered to the positive electrode plate 7 and the adhesive layer 14 of the opposedly facing separator 8. [0049]

The adhesive layer 14 of the separator 8 is adhered to the positive electrode plate 7 and hence, it is possible to prevent foreign substances from being mixed between the positive electrode plate 7 and the separator 8. The adhesive layers 14 of the pair of separators 8 which sandwich the positive electrode plate 7 therebetween are adhered to each other outside the positive electrode plate 7 as viewed in a plan view and hence, it is possible to prevent foreign substances from being mixed to an end surface side of the positive electrode plate 7. Further, peeling of the separators 8 from the positive electrode plate 7 can be prevented and hence, it is possible to prevent mixing of foreign substances between the positive electrode plate

7 and the separators 8 with more certainty. With such a configuration, the energy storage device can prevent internal short circuiting caused by electrodeposition.

[0050]

The adhesive layer 14 of the separator 8 is not partially adhered to the positive electrode plate 7 and the adhesive layer 14 of the opposedly facing separator 8. With such a configuration, it is possible to supply electrolyte solution to inner surfaces of the separators through non-adhered portions between the positive electrode plate 7 and the separators 8 and hence, it is possible to easily pour an electrolyte solution into the separators

8 thus enhancing productivity of the energy storage device. Accordingly, it is preferable that portions where the adhesive layer 14 of the separator 8 is not adhered to the positive electrode plate 7 and the adhesive layer 14 of the opposedly facing separator 8 be continuously formed. In other words, it is preferable that adhered portions of the adhesive layer 14 of the separator 8 adhering to the positive electrode plate 7 and the adhesive layer 14 of the opposedly facing separator 8 be formed into a pattern such as a dotted pattern or a linear pattern where a plurality of adhered portions do not overlap with each other.

[0051]

A lower limit of an average distance between the adhered portions of the adhesive layer 14 to the separator 8 (an average value of a minimum distance between spots when the adhered portion is formed in a spotted manner) is preferably set to 1 mm, and more preferably set to 2 mm. On the other hand, an upper limit of the average distance between adhered portions of the adhesive layer 14 to the separator 8 is preferably set to 5 mm, and more preferably set to 4 mm. By setting the average distance between adhered portions of the adhesive layer 14 to the separator 8 to the above-mentioned lower limit or above, pouring of an electrolyte solution into the separator 8 can be easily performed. By setting the average distance between the adhered portions of the adhesive layer 14 to the separator 8 to the above-mentioned upper limit or below, it is possible to effectively prevent intrusion of foreign substances between the positive electrode plate 7 and the separator 8.

[0052]

The resin layer 12 is formed of a porous resin film.

[0053]

As a main component of the resin layer 12, for example,

polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methylacrylate copolymer, ethylene-ethyl acrylate copolymer, a polyolefin derivative such as chlorinated polyethylene, polyolefin such as ethylene-propylene copolymer, or polyester such as polyethylene- telephthalate and copolyester can be adopted. Among these components, as the main component of the resin layer 12, polyethylene and

polypropylene excellent in electrolyte solution resistance, durability and weldability are suitably used. Here, "main component" means a component having a largest mass content.

[0054]

A lower limit of an average thickness of the resin layer 12 is preferably set to 5 μηι, and more preferably set to 10 μηι. On the other hand, an upper limit of the average thickness of the resin layer 12 is preferably set to 30 μηι, and more preferably set to 20 μηι. By setting the average thickness of the resin layer 12 to the above-mentioned lower limit or above, it is possible to prevent breaking of the resin layer 12 at the time of adhering the separators 8 to each other. Further, by setting the average thickness of the resin layer 12 to the above-mentioned upper limit or below, energy density of the energy storage device can be increased.

[0055]

The heat resistant layer 13 contains a large number of inorganic particles, and a binder for connecting the inorganic particles.

[0056]

As a main component of the inorganic particles, for example, alumina, silica, zirconia, titania, magnesia, ceria, yttria, an oxide such as a zinc oxide and an iron oxide, a nitride such as a silicon nitride, a titanium nitride and a boron nitride, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmoriUonite, sericite, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate or the like can be named. Among these components, as the main component of the inorganic particles of the heat resistant layer 13, alumina, silica and titania are particularly preferable.

[0057]

A lower limit of an average particle size of the inorganic particles contained in the heat resistant layer 13 is preferably set to 1 nm, and more preferably set to 7 nm. On the other hand, an upper limit of the average particle size of the inorganic particles is preferably set to 5 μηι, and more preferably set to 1 μηι. By setting the average particle size of the inorganic particles to the above-mentioned lower limit or above, a ratio of the binder contained in the heat resistant layer 13 is decreased thus enhancing heat resistance of the heat resistant layer 13. By setting the average particle size of the inorganic particles to the above-mentioned upper limit or below, it is possible to provide the homogenized heat resistant layer 13. Here, "average particle size" means a value measured in accordance with JIS- R1670 using a transmission electron microscope (TEM) or a scanning electron microscope (SEM).

[0058]

As a main component of the binder in the heat resistant layer 13, for example, a fluororesin such as polyvinylidene fluoride,

polytetrafluoroethylene, fluororubber such as vinylidene fluoride- hexafluoropropylene-tetrafluoroethylene copolymer, styrene-butadiene copolymer, and hydride of styrene-butadiene copolymer, acrylonitrile- butadiene copolymer and hydride of acrylonitrile-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer and hydride of acrylonitrile- butadiene- styrene copolymer, synthetic rubber such as methacrylic ester- acrylic ester copolymer, styrene-acrylic ester copolymer, and acrylonitrile- acrylic ester copolymer, cellulose derivative such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and ammonium salt of carboxymethyl cellulose, polyetherimide, polyamidimide, polyamide, polyimide such as precursor (polyamic acid or the like) of polyamide, ethylene acrylic acid copolymer such as ethylene-ethyl acrylate copolymer, polyvinyl alcohol (PVA), polyvinyl butylal (PVB), polyvinyl pyrrolidone (PVP), polyvinyl acetate, polyurethane, polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyester or the like can be named.

[0059]

A lower limit of an average thickness of the heat resistant layer 13 is preferably set to 2 μηι, and more preferably set to 4 μηι. On the other hand, an upper limit of the average thickness of the heat resistant layer 13 is preferably set to 10 μηι, and more preferably set to 6 μηι. By setting the average thickness of the heat resistant layer 13 to the above-mentioned lower limit or above, it is possible to prevent breaking of the heat resistant layer 13 at the time of adhering the separators 8. Further, by setting the average thickness of the heat resistant layer 13 to the above-mentioned upper limit or below, energy density of the energy storage device can be increased. [0060]

The adhesive layer 14 can be made of a mixed material containing particles exhibiting ion conductivity and a binder. To be more specific, the adhesive layer 14 can be made of a material containing solid electrolyte particles which can possess ion conductivity by including an electrolyte solution, and a binder exhibiting adhesiveness due to heating, ultrasonic vibration or the like, for example. It is preferable that the adhesive layer 14 have continuous pores so as to allow a liquid and a gas to pass

therethrough.

[0061]

A lower limit of an average thickness of the adhesive layer 14 is preferably set to 0.1 μηι, more preferably set to 0.2 μηι, and further more preferably set to 0.4 μηι. On the other hand, an upper limit of the average thickness of the adhesive layer 14 is preferably set to 5 μηι, more preferably set to 3 μηι, and further more preferably set to 1.2 μηι. By setting the average thickness of the adhesive layer 14 to the above-mentioned lower limit or above, sufficient adhesiveness can be acquired. Further, by setting the average thickness of the adhesive layer 14 to the above-mentioned upper limit or below, sufficient ion conductivity can be acquired.

[0062]

As a material of the solid electrolyte particles of the adhesive layer 14, for example, an inorganic solid electrolyte, a pure solid polymer electrolyte, a gel polymer electrolyte and the like can be named. Among these materials, the gel polymer electrolyte which can increase ion

conductivity and is homogenous thus enabling the easy adjustment of a particle size of the solid electrolyte particles is particularly preferably used.

[0063]

The gel polymer electrolyte is a material which can facilitate handling thereof by turning an electrolyte solution into a gel state by polymer. As a polymer which terns an electrolyte solution into a gel state, for example, vinylidene fluoride-hexafluoropropylene copolymer,

polymethylmethacrylic acid, polyacrylonitrile and the like can be named.

[0064]

As an electrolyte solution of the gel polymer electrolyte, an organic electrolyte solution formed by dissolving a support electrolyte in an organic solvent is used. As the support electrolyte, a lithium salt is preferably used. Although a lithium salt is not particularly limited, for example, LiPF₆, LiAsFe, LiBF₄, LiSbF₆, LiAlCl₄, LiC10₄, CF₃S0₃Li, C₄F₉S0₃Li, CF₃COOLi, (CF₃CO)₂NLi, (CF₃S0₂)₂NLi, (C₂F₅S0₂)NLi and the like can be named. Among these materials, LiPF6, LiC10₄, CF3S0₃Li which are easily dissolved in an organic solvent and exhibit a high dissociation degree are particularly preferably used.

[0065]

An organic solvent used in an electrolyte solution is not particularly limited provided that the organic solvent can dissolve a support electrolyte. For example, carbonates such as a dimethyl carbonate (DMC), an ethylene carbonate (EC), a diethyl carbonate (DEC), a propylene carbonate (PC), a butylene carbonate (BC) and a methyl-ethyl carbonate (MEC), for example, esters such as γ-butyrolactone and methyl formate, for example, ethers such as 1,2 -dimethoxy- ethane and tetrahydrofuran, sulfur- containing compounds such as sulfolane and dimethylsulfoxide and the like can be used singly or in combination of plural kinds of these materials. Among these materials, carbonates having a high dielectric constant and having a wide stable potential region are particularly preferably used.

[0066]

A lower limit of concentration of the support electrolyte in the electrolyte solution is preferably set to 1 mass%, and more preferably set to 5 mass%. On the other hand, an upper limit of the concentration of the support electrolyte in the electrolyte solution is preferably set to 30 mass%, and more preferably set to 20 mass%. By setting the concentration of the support electrolyte in the electrolyte solution within the above-mentioned range, relatively large ion conductivity can be obtained.

[0067]

A lower limit of an average particle size of the solid electrolyte particles is preferably set to 0.1 μηι, and more preferably set to 0.2 μηι. On the other hand, an upper limit of the average particle size of the solid electrolyte particles is preferably set to 2 μηι, and more preferably set to 1 μηι. By setting the average particle size of the solid electrolyte particles to the above-mentioned lower limit or above, it is possible to easily impart ion conductivity to the adhesive layer 14 by bringing solid electrolyte particles into contact with each other. Further, by setting the average particle size of the solid electrolyte particles to the above-mentioned upper limit or below, the adhesive layer 14 can be easily formed into a homogenized film shape.

[0068]

As a shape of the solid electrolyte particles, a shape having small sphericity such as a rod shape, a conical shape, a plate shape is preferable so as to increase ion conductivity by accelerating contact between the solid electrolyte particles, for example.

[0069]

As a binder in the adhesive layer 14, it is sufficient that the binder has adhesiveness to the solid electrolyte particles and the positive active material layer 10. A resin capable of being adhered to the positive active material layer 10 by being heated at a relatively low temperature, that is, a polymer material having a relatively low glass transition point and exhibiting adhesiveness is preferably used.

[0070]

A lower limit of the glass transition point of the binder is preferably set to -50°C, and more preferably set to -45°C. On the other hand, an upper limit of the glass transition point of the binder is preferably set to 50°C, and more preferably set to 45°C. By setting the glass transition point of the binder to the above-mentioned lower limit or above, a strength of the adhesive layer 14 can be ensured. Further, by setting the glass transition point of the binder to the above-mentioned upper limit or below, the separator 8 can be adhered to the positive electrode plate 7 and the opposedly facing separator 8 at a temperature where the resin layer 12 is not damaged.

[0071]

As a main component of the binder, for example, an acrylic polymer and the like can be named. As the acrylic polymer, a nitrile -group - containing acrylic polymer which includes a monomer unit having a nitrile group and a (meth)acrylate acid ester monomer unit is preferably used. Here, the monomer unit having a nitrile group is a structural unit obtained by polymerizing acrylonitrile, methacrylonitrile or the like, for example, and a (meth)acrylate acid ester monomer unit is a monomer unit derived from a compound expressed by

(in the formula, R¹ indicating a hydrogen atom or a methyl group, and R² indicating an alkyl group or a cycloalkyl group). The nitrile group containing acrylic polymer may contain an ethylenic unsaturated acid monomer unit obtained by

polymerizing an ethylenic unsaturated acid monomer in addition to the monomer unit having a nitrile group and the (meth)acrylate acid ester monomer unit. Further, nitrile group containing acrylic polymer may be formed in a cross-linking manner.

[0072]

A lower limit of a ratio of the solid electrolyte particles in the adhesive layer 14 is preferably set to 70 mass%, and more preferably set to 80 mass%. On the other hand, an upper limit of the ratio of the solid electrolyte particles in the adhesive layer 14 is preferably set to 95 mass%, and more preferably set to 90 mass%. By setting the ratio of the solid electrolyte particles in the adhesive layer 14 to the above-mentioned lower limit or above, it is possible to impart sufficient ion conductivity to the adhesive layer 14. Further, by setting the ratio of the solid electrolyte particles in the adhesive layer 14 to the above-mentioned upper limit or below, it is possible to impart sufficient adhesiveness to the adhesive layer 14 while setting a ratio of the binder relative to the binder to a fixed value or more. [0073]

Hereinafter, a manufacturing method of the bag-packed positive electrode plate according to one embodiment of the present invention is described with reference to symbols shown in Fig. 2. The bag-packed positive electrode plate 5 shown in Fig. 2 is not limited to a bag-packed positive electrode plate manufactured by the manufacturing method described hereinafter.

[0074]

The bag-packed positive electrode plate 5 can be manufactured by a method including: sandwiching the positive electrode plate 7 by the pair of separators 8 each having the resin layer 12, the heat resistant layer 13, and the adhesive layer 14 (stacking step); and sandwiching a layered product of the positive electrode plate 7 and the pair of separators 8 by a heating mold which is heated to a temperature lower than a melting point of the resin layer 12 (pressing step).

[0075]

In the stacking step, the adhesive layers 14 of the separators 8 are respectively brought into contact with the positive electrode plate 7, and the positive electrode plate 7 and the pair of separators 8 are stacked to each other such that the separators 8 envelopes the active material region of the positive electrode plate 7 as viewed in a plan view.

[0076]

In the pressing step, a pair of heating molds is heated to a

temperature below a melting point of the resin layer 12 and equal to or above a glass transition point of the binder of the adhesive layer 14, and the layered product of the positive electrode plate 7 and the pair of separators 8 is sandwiched and pressurized by the pair of heating molds. As a specific example of a temperature of the heating molds, the temperature can be set to approximately 100°C, for example. A pressing pressure by the heating molds can be set to approximately lN/cm², for example. A pressing time by the heating molds can be set to approximately 3 seconds.

[0077]

The heating molds make the adhesive layers 14 adhere to at least portions of the positive electrode plate 7 by pressure-joining as viewed in a plan view and, at the same time, the heating molds make the adhesive layers 14 which opposedly face each other outside the positive electrode plate 7 as viewed in a plan view adhere to each other at least partially by pressure joining.

[0078]

To be more specific, it is preferable that the heating mold has a groove on a pressing surface thereof such that a portion where the adhesive layer 14 is not adhered to the positive electrode plate 7 is formed on the separator 8. A lower limit of a depth of the groove formed on the heating mold is preferably set to 0.5 mm, and more preferably set to 0.8 mm. On the other hand, an upper limit of the depth of the groove formed on the heating mold is preferably set to 3 mm, and more preferably set to 2 mm. By setting the depth of the groove formed on the heating mold to the above- mentioned lower limit or above, the portion of the heating mold where the adhesive layer 14 is not adhered to the positive electrode plate 7 can be formed with certainty. Further, by setting the depth of the groove of the heating mold to the above-mentioned upper limit or below, the heating mold can be easily formed.

[0079]

In the pressing step, a pair of vibrating molds at least one of which is ultrasonically vibrated may be used in place of the heating molds. By using the vibrating molds which are ultrasonically vibrated, the adhesive layer 14 can be adhered to the positive electrode plate 7 and the opposedly facing adhesive layer 14 in a relatively short time. Accordingly, a cycle time of the pressing step can be shortened thus realizing the reduction of a manufacturing cost of the bag-packed positive electrode plate 5.

[0080]

The bag-packed positive electrode plate 5 manufactured as described above can effectively prevent intrusion of foreign substances between the positive electrode plate 7 and the separator 8 as described above.

Accordingly, in the case where the layered electrode assembly 1 is formed by stacking the bag-packed positive electrode plates 5 and the negative electrode plates 6 to each other and the layered electrode assembly 1 is incorporated in the energy storage device, it is possible to prevent the occurrence of internal short-circuiting caused by electrodeposition.

[0081]

The negative electrode plates 6 are stacked in the layered electrode assembly 1 without being bag-packed unlike the positive electrode plates 7.

[0082]

The negative electrode plate 6 includes^ a foil-like or sheet-like negative electrode current collector having conductivity! and a negative active material layer which is stacked on a surface of the negative electrode current collector. To be more specific, the negative electrode plate 6 includes^ an active material region having a rectangular shape as viewed in a plan view where the active material layer 12 is stacked on a surface of the negative electrode current collector, and a negative electrode tab which extends from the active material region in a strip shape having a width smaller than a width of the active material region and is connected to the negative electrode terminal 4.

[0083]

Although the negative electrode current collector can be formed substantially in the same manner as the above-mentioned positive electrode current collector 9, copper or a copper alloy is preferably used as a material for forming the negative electrode current collector. That is, a copper foil is preferably used as the negative electrode current collector of the negative electrode 6. As a copper foil, a rolled copper foil, an electrolytic copper foil and the like can be exemplified.

[0084]

The negative active material layer is made of a so-called negative electrode plate mixture containing a negative active material. The negative electrode plate mixture which forms the negative active material layer contains arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like when necessary. As the arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like used for forming the negative active material layer, arbitrary components substantially equal to the arbitrary components used for forming the positive active material layer 10 can be used.

[0085]

As the negative active material, a material which can occlude and discharge lithium ions is preferably used. As a specific negative active material, metal such as lithium or a lithium alloy, a metal oxide! a polyphosphoric acid compound, a carbon material such as graphite, non^¬ crystalline carbon (easily graphitizable carbon or hardly graphitizable carbon) or the like can be named, for example.

[0086]

Among the above-mentioned negative active materials, from a viewpoint of setting a discharge capacity per unit opposedly facing area between the positive electrode plate 7 and the negative electrode plate 6 within a preferable range, it is preferable to use Si, an Si oxide, Sn, an Sn oxide or a combination of these materials. It is particularly preferable to use an Si oxide. Si and Sn can have a discharge capacity approximately three times as large as a discharge capacity of graphite when Si and Sn are used in the form of an oxide.

[0087]

When an Si oxide is used as the negative active material, a ratio of the number of atoms of oxygen (O) contained in an Si oxide with respect to the number of atoms of Si is preferably set to more than 0 to less than 2. That is, as Si oxide, a compound expressed as SiO_x (0 < x < 2) is preferably used. Further, the ratio of the number of atoms of 0 with respect to the number of atoms of Si is preferably set to a value which falls within a range of from 0.5 to 1.5 inclusive. [0088]

As the negative active material, the above-mentioned materials can be used in a single form, or two or more kinds of the materials may be used by mixing. For example, by using an Si oxide and other negative active materials by mixing, both discharge capacities per unit opposedly facing area between the positive electrode plate 7 and the negative electrode plate 6 and a ratio of a mass of a positive active material with respect to a mass of a negative active material described later can be adjusted to suitable values. As other negative active materials used by being mixed with an Si oxide, carbon materials such as graphite, hard carbon, soft carbon, coke, acetylene black, Ketjen black, vapor phase growth carbon fibers, fullerene, and activated carbon can be named. Among these carbon materials, only one kind of material may be mixed with an Si oxide, or two or more kinds of materials may be mixed with an Si oxide in an arbitrary combination or at an arbitrary ratio. Among these other negative active materials, graphite having a relatively low charge- discharge potential is preferably used. By using graphite as the negative active material, it is possible to obtain a secondary battery element having high energy density. As graphite used in a form that graphite is mixed with an Si oxide, flaky graphite, spherical graphite, artificial graphite, natural graphite and the like can be named. Among these graphite, flaky graphite which can easily maintain its contact with Si oxide particle surfaces even when charging and discharging of the energy storage device are repeated is preferably used.

[0089]

Further, the negative active material layer may contain^ a small amount of a typical nonmetallic element such as B, N, P, F, CI, Br, I; a typical metallic element such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge! and a transition metallic element such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W in addition to an Si oxide.

[0090]

It is preferable that the above-mentioned Si oxide (a material expressed by a general formula SiO_x) include both an S1O2 phase and an Si phase. In such an Si oxide, lithium is occluded in or discharged from Si in a matrix of S1O2 and hence, such an Si oxide exhibits a small change in volume and exhibits an excellent charge- discharge cycle characteristic.

[0091]

An average particle size of the Si oxide is preferably set to a value which falls within a range of from 1 μηι to 15 μηι inclusive. By setting the average particle size of the Si oxide to the above-mentioned upper limit or below, a charge-discharge cycle characteristic of the energy storage device can be enhanced.

[0092]

As the Si oxide, various Si oxides can be used ranging from a high crystalline Si oxide to an amorphous Si oxide. Further, as the Si oxide, an Si oxide which is washed by an acid such as a hydrogen fluoride or a sulfuric acid, or an Si oxide which is reduced by hydrogen may be used.

[0093]

A lower limit of a content of an Si oxide in the negative active material is preferably set to 30 mass%, more preferably set to 50 mass%, and further more preferably set to 70 mass%. On the other hand, an upper limit of the content of the Si oxide is usually set to 100 mass%, and is preferably set to 90 mass%.

[0094]

A lower limit of a content of the negative active material in the negative active material layer is preferably set to 60 mass%, more

preferably set to 80 mass%, and further more preferably set to 90 mass%. On the other hand, an upper limit of the content of the negative active material is preferably set to 99 mass%, and more preferably set to 98 mass%. By setting the content of the negative active material particles within the above-mentioned range, energy density of the energy storage device can be increased.

[0095]

A lower limit of a content of a binder in the negative active material layer is preferably set to 1 mass%, and more preferably set to 5 mass%. On the other hand, an upper limit of the content of the binder is preferably set to 20 mass%, and more preferably set to 15 mass%. By setting the content of the binder to the above-mentioned range, the negative active material can be held in a stable manner.

[0096]

A lower limit of an average thickness of the active material layer is preferably set to 10 μηι, and more preferably set to 20 μηι. On the other hand, an upper limit of the average thickness of the negative active material layer is preferably set to 100 μηι, and more preferably set to 80 μηι. By setting the average thickness of the negative active material layer to the above-mentioned lower limit or above, a reaction at the negative electrode can be sufficiently activated. Further, by setting the average thickness of the negative active material layer to the above-mentioned upper limit or below, energy density of the energy storage device can be increased.

[0097]

The outer case 2 is a hermetically-closed container which

accommodates the layered electrode assembly 1 therein and in which an electrolyte is sealed.

[0098]

As a material for forming the outer case 2, provided that the material has sealability capable of sealing electrolyte and a strength capable of protecting the layered electrode assembly 1, a resin or the like may be used, for example. However, metal is preferably used. In other words, although the outer case 2 may be a bag-shaped body formed of laminated film and having flexibility or the like, for example, it is preferable to use a robust metal case capable of protecting the layered electrode assembly 1 with more certainty.

[0099]

As an electrolyte sealed in the outer case 2 together with the layered electrode assembly 1, a known electrolyte usually used in the energy storage device can be used. For example, a solution obtained by dissolving lithium hexafluorophosphate (LiPFe) or the like in a solvent containing: a cyclic carbonate such as an ethylene carbonate (EC), a propylene carbonate (PC) or a butylene carbonate (BC); or a chain carbonate such as a diethyl carbonate (DEC), a dimethyl carbonate (DMC) or an ethyl-methyl carbonate (EMC) can be used. [0100]

The above-mentioned embodiment is not intended to limit the configuration of the present invention. Accordingly, it should be construed that the above-mentioned embodiment can be modified by omission, replacement or addition of constitutional elements of respective parts of the embodiment based on the description of this specification and the common general technical knowledge, and all these modifications also fall within the scope of the present invention.

INDUSTRIAL APPLICABILITY

[0101]

The bag-packed positive electrode plate, the layered electrode assembly, and the energy storage device according to the present invention are preferably applicable to a secondary battery, and are used particularly preferably as a power source of a vehicle such as an electric vehicle, a plug- in hybrid electric vehicle (PHEV).

DESCRIPTION OF REFERENCE SIGNS

[0102]

l: layered electrode assembly

2- outer case

3^: positive electrode terminal

4^'· negative electrode terminal

5: bag-packed positive electrode plate

6: negative electrode plate

T- positive electrode plate

8^ separator ^: positive electrode current collector0: positive active material layer1: positive electrode tab

2: resin layer

3: heat resistant layer

4: adhesive layer

Claims

1. A bag-packed positive electrode plate comprising:

a positive electrode plate! and

a pair of separators which sandwiches the positive electrode plate therebetween,

wherein the separator has a resin layer, a heat resistant layer which is stacked on the resin layer, and an adhesive layer which is stacked on a surface of the heat resistant layer which opposedly faces the positive electrode plate, and

the adhesive layers of the pair of separators are adhered to the positive electrode plate and are adhered to each other outside the positive electrode plate as viewed in a plan view.

2. The bag-packed positive electrode plate according to claim 1, wherein the adhesive layer is not partially adhered to the positive electrode plate and the other adhesive layer which the adhesive layer opposedly faces.

3. The bag-packed positive electrode plate according to claim 1 or 2, wherein the adhesive layer is formed of a mixed material which contains^: particles including an electrolyte solution and exhibiting ion conductivity! and a binder.

4. A layered electrode body comprising:

a plurality of the bag-packed positive electrode plates according to any one of claims 1 to 3! and a plurality of negative electrode plates,

wherein the bag-packed positive electrode and the negative electrode plate are alternately stacked with each other

5. An energy storage device comprising:

the layered electrode assembly according to claim 4; and

an outer case which accommodates the layered electrode assembly therein.

6. A manufacturing method of a bag-packed positive electrode plate comprising:

sandwiching a positive electrode plate by a pair of separators, each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and

sandwiching a layered product of the positive electrode plate and the pair of separators using a heating mold heated at a temperature lower than a melting point of the resin layer thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.

7. A manufacturing method of a bag-packed positive electrode plate comprising: sandwiching a positive electrode plate by a pair of separators, each having a resin layer, a heat resistant layer stacked on the resin layer, and an adhesive layer stacked on a surface of the heat resistant layer opposedly facing the positive electrode plate, the pair of separators enveloping the positive electrode plate as viewed in a plan view! and

sandwiching a layered product of the positive electrode plate and the pair of separators by a pair of heating molds in which at least one of the heating mold is ultrasonically vibrated thus adhering the adhesive layers to the positive electrode plate and making the adhesive layers which opposedly face each other outside the positive electrode plate as viewed in a plan view adhere to each other.