JPH11260406A - Polymer electrolyte lithium secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer electrolyte lithium secondary battery with high productivity, high reliability, and no generation of internal short circuit in the production process and in falling. SOLUTION: A polymer electrolyte lithium secondary battery is constituted by stacking a positive electrode 2 capable of absorbing/releasing lithium ions, a lithium ion conductive polymer electrolyte layer 3, a negative electrode 4 capable of absorbing 1 releasing lithium ions, the lithium ion conductive polymer electrolyte layer 3, and the positive electrode 2 capable of absorbing/releasing lithium ions in order, making the area of the positive electrode 2 smaller than those of the electrolyte layer 3 and the negative electrode 4, and stacking unit cells 11 -13 in which a frame-shaped space is formed in the electrolyte layer part positioned in the surroundings of the positive electrode 2, and frame-shaped or U-shaped insulating spacers 121 , 122 are arranged between the stacked unit cells 11 -13 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer electrolyte lithium secondary battery in which a plurality of unit cells are stacked.

[0002]

2. Description of the Related Art In recent years, with the development of electronic equipment, there has been a demand for the development of a secondary battery that is small, lightweight, has a high energy density, and can be repeatedly charged and discharged. As such a secondary battery, a negative electrode containing lithium or a lithium alloy as an active material and a suspension containing an active material containing an oxide, sulfide, or selenide of molybdenum, vanadium, titanium, or niobium were applied. A non-aqueous electrolyte secondary battery including a positive electrode made of a current collector and a non-aqueous electrolyte is known.

However, a secondary battery provided with a negative electrode using lithium or a lithium alloy as an active material has a problem that the charge / discharge cycle life is short because repetition of charge / discharge cycles generates lithium dendrites in the negative electrode. .

[0004] For this reason, a suspension containing a carbonaceous material that occludes and releases lithium ions, such as coke, graphite, carbon fiber, fired resin, and pyrolytic gas phase carbon, is applied to the negative electrode. A non-aqueous electrolyte secondary battery using a current collector has been proposed. In the secondary battery, the deterioration of the negative electrode characteristics due to dendrite deposition can be improved, so that the battery life and safety can be improved.

On the other hand, US Pat. No. 5,429,891 discloses a rechargeable lithium intercalation having a hybrid polymer electrolyte which has been made flexible by adding a polymer to the cathode, anode and electrolyte layers. A battery, that is, a polymer electrolyte lithium secondary battery is disclosed. Such a polymer electrolyte lithium secondary battery is manufactured by the following method.

First, a plasticizer such as DBP (dibutyl phthalate) which can be removed later, vinylidene fluoride (VdF) and hexafluoropropylene (H
An FP) copolymer and a positive electrode material capable of inserting and extracting lithium are mixed in the presence of a solvent, formed into a sheet, and the obtained sheet is laminated on a current collector to form an electrolytic solution. A non-impregnated positive electrode material is produced. Also, a plasticizer and VdF
The HFP copolymer is mixed in the presence of a solvent, and the mixture is formed into a sheet to form an electrolyte-unimpregnated separator sheet. Further, a plasticizer, a copolymer of VdF-HFP, and a carbonaceous material capable of occluding and releasing lithium are mixed in the presence of a solvent, formed into a sheet, and the obtained sheet is collected with a current collector. An electrolyte-unimpregnated negative electrode material is produced by laminating on a body. Subsequently, a positive electrode material, a separator sheet, a negative electrode material, a separator sheet and a positive electrode material are laminated in this order, and thermocompression-bonded to produce an electrolyte-impregnated unit cell. Subsequently, after extracting and removing the plasticizer in the unit cell with a solvent, a plurality of the plasticizers are stacked, and further impregnated with a non-aqueous electrolyte, whereby the polymer electrolyte lithium secondary battery in which each of the unit cells is connected in parallel is connected. The next battery is manufactured.

In the above-mentioned polymer electrolyte lithium secondary battery, the area of the negative electrode is made larger than that of the positive electrode in order to prevent lithium dendrite. For this reason, a frame-shaped space is formed in the separator located around the positive electrode.

In such a conventional polymer electrolyte lithium secondary battery, since each unit cell contains substantially no liquid component and its constituent layers are integrated, a simple exterior material such as a laminate film is used. Can be used, and it is thin, lightweight and excellent in safety.

[0009]

However, since the conventional polymer electrolyte lithium secondary battery has a structure in which the unit cells are simply stacked, a deviation occurs between the unit cells in the manufacturing process. When such a shift occurs, each layer constituting the unit cell is very thin,
The positive and negative electrodes come into contact, causing an internal short circuit. Also, when the polymer electrolyte lithium secondary battery is dropped by mistake, a shift occurs between the unit cells, and the positive and negative electrodes come into contact with each other to cause an internal short circuit.

An object of the present invention is to provide a polymer electrolyte lithium secondary battery in which an internal short circuit is prevented during a manufacturing process and a drop.

[0011]

According to the present invention, there is provided a polymer electrolyte lithium secondary battery comprising: a positive electrode capable of inserting and extracting lithium ions; a lithium ion conductive polymer electrolyte layer;
A negative electrode capable of inserting and extracting lithium ions, a lithium ion conductive polymer electrolyte layer,
The dischargeable positive electrode and the positive electrode are laminated in this order, and the area of the positive electrode is smaller than that of the electrolyte layer and the negative electrode,
In a polymer electrolyte lithium secondary battery having a structure in which a plurality of unit cells each having a frame-shaped space formed in the electrolyte layer portion located around the positive electrode, a frame-shaped or U-shaped insulation is provided between the stacked unit cells. A conductive spacer is disposed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a polymer electrolyte lithium secondary battery according to the present invention will be described with reference to FIGS.

[0013] For example three unit cells 1 ₁ to 1 _3, a positive electrode 2 capable of occluding and releasing lithium ions, a lithium ion conductive polymer electrolyte layer 3, and capable of absorbing and releasing the negative electrode 4 lithium ions , Lithium ion conductive polymer electrolyte layer 3 and positive electrode 2 capable of inserting and extracting lithium ions
Are laminated and integrated in this order.

The positive electrode 2 has a structure in which a positive electrode layer 7 is supported on a current collector 6 having a strip-shaped terminal portion 5 extending to the outside.

The negative electrode 4 has a structure in which a negative electrode layer 10 is supported on a current collector 9 having a strip-shaped terminal portion 8 extending to the outside.

The positive electrode 2 has a smaller area than the electrolyte layer 3 and the negative electrode 4, and as shown in FIG.
A frame-shaped space 11 is formed in the portion of the electrolyte layer 3 located in the periphery.

[0017] The plurality of unit cells 1 ₁ to 1 ₃ are laminated in this order so positive electrode 2 is in contact with each other. Frame-shaped insulating spacer 12 _1, the first as shown in FIG. 3, is interposed in the second unit cell 1 _1, 1 ₂ between. In other words, the frame-like insulating spacer 12 ₁ is slightly larger inner area than the positive electrode 2, the first, second unit cell 1 _1, 1 ₂ of the positive electrode 2 is between superimposed region It is arranged in the surrounding frame-shaped space 11. The said spacer 12 ₁ portions where the belt-like terminal portions 5 of the positive electrode 2 to be laminated to each other is extended, each notch 13 and 13 are formed. Further, the spacer 12 ₁ has a width that fits the frame-like space 11. The spacer 12 ₁ a frame-shaped insulating spacer 12 ₂ having the same shape are interposed between the second, third unit cell 1 _2, 1 _3.

[0018] The unit cell 1 ₁ to 1 ₃ is housed in the exterior film 14, is hermetically sealed by fusing the opening of the film 14. Terminal portion 8 of the negative electrode 4 of the unit cells 1 ₁ to 1 _3, wherein the casing film 1
4 and are connected to one end of the external lead 15. The external leads 15 are connected to the exterior film 1.
4 extend to the outside through the fusion portion 16. Terminal portions 5 of the positive electrode 2 of the unit cells 1 ₁ to 1 _3, wherein bundled together by casing films within 14, and is connected to an external lead (not shown) which is extended to the outside through the fused portion 16 .

Next, the positive electrode 2, the lithium ion conductive polymer electrolyte layer 3, the negative electrode 4, the insulating spacers 12 ₁ and 12 ₂ and the outer film 14 will be described.

1) Positive Electrode 2 The positive electrode 2 is made of an active material for absorbing and releasing lithium ions on both sides of an aluminum current collector 6 having an aluminum strip terminal portion 5, a non-aqueous electrolyte, and a polymer for holding the electrolyte. Has a structure in which the positive electrode layer 7 containing is supported.

Examples of the active material include various oxides (eg, lithium manganese composite oxide such as LiMn ₂ O ₄ , manganese dioxide, lithium-containing nickel oxide such as LiNiO _2, and lithium-containing cobalt oxide such as LiCoO _2). Materials, lithium-containing nickel-cobalt oxide, lithium-containing amorphous vanadium pentoxide, etc.)
Chalcogen compounds (for example, titanium disulfide, molybdenum disulfide, etc.) can be exemplified. Among them, lithium manganese composite oxide, lithium-containing cobalt oxide,
It is preferable to use lithium-containing nickel oxide.

The non-aqueous electrolyte is prepared by dissolving an electrolyte in a non-aqueous solvent.

As the non-aqueous solvent, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (D
MC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (γ-
BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like. The non-aqueous solvents may be used alone or as a mixture of two or more.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (Li
PF ₆ ), lithium borotetrafluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide [LiN (CF ₃
SO ₃ ) ₂ ].

The amount of the electrolyte dissolved in the non-aqueous solvent is desirably 0.2 mol / L to 2 mol / L.

Examples of the polymer holding the nonaqueous electrolyte include a polyethylene oxide derivative, a polypropylene oxide derivative, a polymer containing the derivative,
A copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP) or the like can be used. The copolymerization ratio of the HFP depends on the method of synthesizing the copolymer, but is usually at most about 20% by weight.

[0027] The positive electrode layer may contain a conductive material from the viewpoint of improving conductivity. Examples of the conductive material include artificial graphite, carbon black (eg, acetylene black), nickel powder, and the like.

As the current collector, for example, an expanded metal made of aluminum, a mesh made of aluminum, a punched metal made of aluminum, or the like can be used.

The band-shaped terminal portion is formed by extending the current collector as it is or by using an aluminum foil connected to the current collector.

2) Lithium-ion conductive polymer electrolyte layer 3 The electrolyte layer 3 contains a non-aqueous electrolyte and a polymer holding the electrolyte.

As the non-aqueous electrolyte and the polymer, those similar to those described for the positive electrode described above are used.

The electrolyte layer may contain an inorganic filler such as SiO ₂ powder in order to improve the compressive strength.

3) Negative electrode 4 This negative electrode 4 is made of a copper current collector 9 having a copper strip terminal 8.
Has a structure in which a negative electrode layer 10 containing a carbonaceous material capable of inserting and extracting lithium ions, a non-aqueous electrolyte, and a polymer holding the electrolyte is supported on both surfaces.

Examples of the carbonaceous material include those obtained by firing organic polymer compounds (eg, phenolic resin, polyacrylonitrile, cellulose, etc.), those obtained by firing coke and mesophase pitch. And carbonaceous materials represented by artificial graphite, natural graphite and the like.
Above all, it is preferable to use a carbonaceous material obtained by firing the mesophase pitch at a temperature of 500 ° C to 3000 ° C under normal pressure or reduced pressure.

As the non-aqueous electrolyte and the polymer, those similar to those described for the above-mentioned positive electrode are used.

The negative electrode layer is made of artificial graphite, natural graphite, carbon black, acetylene black,
It is allowed to contain conductive materials such as Ketjen black, nickel powder, and polyphenylene derivatives, and fillers such as olefin polymers and carbon fibers.

As the current collector, for example, a copper expanded metal, a copper mesh, a copper punched metal, or the like can be used.

The band-like terminal portion is formed by extending the current collector as it is or by using a copper foil connected to the current collector.

[0039] 4) insulating spacer 12 _1, 12 ₂ spacers 12 _1, 12 _2, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP) and modified products of these resins, the electrolyte solution, such as polyimide Resin can be used.

5) Exterior Film 14 The exterior film 14 is a laminated film in which a heat-fusible resin film, a metal foil, and a rigid resin film are laminated at least in this order from the inner surface side. As the heat-fusible resin, for example, polyethylene (PE), ionomer, ethylene vinyl acetate (EVA) and the like can be used. As the metal foil, for example, Al
A foil, a Ni foil or the like can also be used, but an Al foil that can be made thinner is preferable. As the rigid resin,
For example, polyethylene terephthalate (PET), nylon or the like can be used. However, the rigid resin film may be a combination of two or more films.

The unit cells are not limited to the case where three cells are stacked as shown in FIGS.
More than one sheet may be stacked.

The insulating spacer is not limited to the frame shape as described above, and a U-shaped spacer 17 may be used as shown in FIG. When interposed between the unit cells using such a U-shaped spacer 17, the open side face is arranged so as to be located on the terminal side of the positive electrode of the unit cell.

Next, an example of a method for producing a polymer electrolyte lithium secondary battery according to the present invention will be described below.

First, a polymer holding at least a non-aqueous electrolyte, an active material capable of inserting and extracting lithium and a plasticizer are mixed in the presence of a solvent, and the mixture is formed into a sheet.
The obtained sheet is laminated on a portion of the current collector having a strip-shaped terminal portion other than the terminal portion, to prepare a positive electrode material not impregnated with an electrolyte.

Examples of the plasticizer include dibutyl phthalate (DBP), dimethyl phthalate (DMP), and ethyl phthalyl ethyl glycolate (EPEG).

Further, at least a polymer holding a non-aqueous electrolyte and a plasticizer are mixed in the presence of a solvent, and the mixture is formed into a sheet to form an electrolyte-unimpregnated electrolyte layer.

Further, at least a polymer holding a non-aqueous electrolyte, a carbonaceous material capable of inserting and extracting lithium and a plasticizer are mixed in the presence of a solvent, and the mixture is formed into a sheet. A negative electrode material not impregnated with an electrolyte is produced by laminating the current collector having a strip-shaped terminal portion on a portion other than the terminal portion.

Next, the positive electrode material, the electrolyte layer, the negative electrode material, the electrolyte layer and the positive electrode material are laminated in this order, and thermocompression-bonded to produce an electrolyte-unimpregnated unit cell. Subsequently, after extracting and removing the plasticizer in the unit cells with a solvent, a plurality of the plasticizers are laminated, and a frame-shaped or U-shaped insulating spacer is interposed between the unit cells.
Subsequently, the laminate of the unit cells was housed in an exterior film, and a non-aqueous electrolyte was injected from the opening of the exterior film to impregnate the constituent members of each unit cell with the electrolyte. The unit cells are connected in parallel by fusing the opening and extending the external leads connected to the positive terminal and the negative terminal of each unit cell to the outside through the fused part. To manufacture a polymer electrolyte lithium secondary battery.

The polymer electrolyte lithium secondary battery according to the present invention described above comprises a positive electrode capable of occluding and releasing lithium ions, a lithium ion conductive polymer electrolyte layer, and a negative electrode capable of occluding and releasing lithium ions. A lithium ion conductive polymer electrolyte layer and a positive electrode capable of occluding and releasing lithium ions are laminated in this order, and the area of the positive electrode is smaller than that of the electrolyte layer and the negative electrode, and is located around the positive electrode. In a polymer electrolyte lithium secondary battery having a structure in which a plurality of unit cells in which a frame-shaped space is formed in the electrolyte layer portion, a frame-shaped or U-shaped insulating spacer is disposed between the stacked unit cells. Having a structure.

According to such a structure, a plurality of stacked unit cells can be mutually connected by interposing an insulating spacer in a frame-shaped space around the positive electrode in contact with each other of the unit cells stacked vertically. Can be fixed. As a result, it is possible to prevent adjacent unit cells from shifting in a direction perpendicular to the stacking direction (in the surface direction of the unit cells) during manufacturing or dropping, and to prevent the positive electrodes adjacent above and below each unit cell. The periphery can be insulated by the spacer. Therefore, it is possible to obtain a polymer electrolyte lithium secondary battery in which the positive and negative electrodes of the upper and lower unit cells are prevented from coming into contact with each other and causing an internal short circuit.

In particular, when a frame-shaped spacer is used, a plurality of stacked unit cells can be fixed to each other in all two-dimensional directions. And the negative electrode can be more reliably prevented from contacting with each other to cause an internal short circuit.

Further, the insulating spacers are arranged in a frame-shaped space around the positive electrode in contact with each other of the unit cells stacked one above the other, so that an increase in volume due to the arrangement of the spacers can be avoided. Energy density equivalent to that of a secondary battery can be secured.

[0053]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Example 1) <Preparation of positive electrode material not impregnated with nonaqueous electrolyte> A lithium manganese composite oxide having a composition formula of LiMn ₂ O ₄ as an active material, carbon black, and vinylidene fluoride in acetone Ride-hexafluoropropylene (VdF-HF
A paste was prepared by mixing a mixture of the copolymer powder P) and dibutyl phthalate (DBP) in acetone. The LiMn ₂ O ₄ , carbon black, VdF-
The mixing ratio of the HFP copolymer powder and DBP is 56% by weight, 5% by weight, 17% by weight, and 22% by weight. Subsequently, the paste was mixed with polyethylene terephthalate (P
ET) It was applied on a film so as to have a thickness of 100 μm and a width of 200 mm to form a sheet. Subsequently, the positive electrode layer was heat-pressed with a hot roll to both surfaces of a current collector made of an aluminum expanded metal having an aluminum strip-shaped terminal portion, except for the terminal portion, and then cut to obtain a 30 mm × 52 mm electrolytic solution. A positive electrode material having an impregnated positive electrode layer was produced.

<Preparation of Non-Aqueous Electrolyte Impregnated Negative Electrode>
A paste was prepared by mixing the powder heat-treated at 0 ° C., the VdF-HFP copolymer powder, and DBP in acetone. The carbon fiber powder, VdF-HF
The mixing ratio of the P copolymer powder and DBP is 58% by weight, 17% by weight, and 25% by weight. Subsequently, the paste was applied on a polyethylene terephthalate (PET) film so as to have a thickness of 100 μm and a width of 200 mm to form a sheet. Subsequently, the negative electrode layer was heat-pressed with a hot roll to both sides of a porous current collector made of a copper expanded metal having a copper strip-shaped terminal portion except for the terminal portion, and then cut to obtain a 32 mm × 54 mm electrolyte solution. A negative electrode material having an impregnated negative electrode layer was produced.

<Preparation of polymer electrolyte material not impregnated with non-aqueous electrolyte> 33.3 parts by weight of silicon oxide powder, VdF-HFP
A paste was prepared by mixing 22.2 parts by weight of the copolymer powder and 44.5 parts by weight of DBP in acetone. Subsequently, the paste was applied on a polyethylene terephthalate (PET) film to a thickness of 100 μm and a width of 2 μm.
It was applied to a thickness of 00 mm, formed into a sheet, and then cut to prepare a 32 mm × 54 mm non-aqueous electrolyte unimpregnated polymer electrolyte material.

<Preparation of Non-Aqueous Electrolyte> LiPF ₆ as an electrolyte was added to a non-aqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 2: 1 at a concentration of 1 mol / mol. 1 to prepare a non-aqueous electrolyte.

Next, the obtained positive electrode material, polymer electrolyte material, negative electrode material, polymer electrolyte material and positive electrode material are stacked in this order, and these are heated and pressed by a rigid roll heated to 125 ° C. to obtain a non-aqueous solution. An electrolyte-unimpregnated unit cell was prepared.

Next, the unit cell was immersed in a container containing n-decane, and allowed to stand for 15 minutes while stirring with a magnetic stirrer placed in the container. This operation was repeated until the concentration of the plasticizer (DBP) in n-decane by gas chromatography became 20 ppm or less, thereby removing the plasticizer from each component of the non-aqueous electrolyte non-impregnated unit cell.

Next, the three unit cells from which the plasticizer had been removed were overlapped so that the non-aqueous electrolyte unimpregnated cathode materials were in contact with each other, and a 200 μm-thick PET-made frame was placed between vertically adjacent unit cells. After interposing the spacer, the positive electrode terminal portion and the negative electrode terminal portion of the unit cell are respectively bundled, an aluminum external lead is connected to the bundled positive electrode terminal portion, and the bundled negative electrode terminal portion is connected. External copper leads were connected. In addition, the spacer has a cutout portion at a position where the terminal portion of the positive electrode is located when the unit cells are stacked. Subsequently, these are housed in an exterior film having an opening on one side, the nonaqueous electrolyte is injected into the exterior film, and the constituent members of each unit cell are impregnated with the electrolyte. And the external leads connected to the positive electrode terminal and the negative electrode terminal of each unit cell are extended to the outside through this fused portion, thereby forming three unit cells (theoretical capacity: 85 mAh). ) Were connected in parallel to produce 50 polymer electrolyte lithium secondary batteries having the structure shown in FIGS. 1 and 2 described above.

Example 2 200 μm thick spacer
Fifty polymer electrolyte lithium secondary batteries were manufactured in the same manner as in Example 1, except that a m-shaped PET-shaped one was used.

Comparative Example 1 Fifty polymer electrolyte lithium secondary batteries were manufactured in the same manner as in Example 1 except that no spacer was interposed between the unit cells.

With respect to the obtained secondary batteries of Examples 1 and 2 and Comparative Example 1, the number of internal short-circuit defects during the manufacturing process was examined. The results are shown in Table 1 below.

In the obtained secondary batteries of Examples 1 and 2 and Comparative Example 1, 20 batteries were determined to be good after being manufactured, and were dropped five times on concrete from a height of 1.2 m. The number of subsequent internal short-circuit defects was examined. The results are shown in Table 1 below.

[0065]

[Table 1]

As is clear from Table 1, the secondary batteries of Examples 1 and 2 in which a spacer is interposed between the unit cells are:
It can be seen that the internal short-circuit failure during the manufacturing process can be significantly reduced and the productivity (yield) can be significantly improved as compared with the secondary battery of Comparative Example 1 in which no spacer is interposed.

Further, it can be seen that the secondary batteries of Examples 1 and 2 can reduce the internal short-circuit defect in the drop test and have high reliability as compared with the secondary battery of Comparative Example 1 in which no spacer is interposed.

Further, in the secondary batteries of Examples 1 and 2, a frame-shaped or U-shaped spacer is interposed in a frame-shaped space located around the positive electrode, and the unit cell volume is different from that of the secondary battery of Comparative Example 1. Therefore, an energy density equivalent to that of the secondary battery of Comparative Example 1 can be secured.

[0069]

As described above in detail, according to the present invention, it is possible to provide a high-productivity and high-reliability polymer electrolyte lithium secondary battery in which an internal short circuit is prevented during a manufacturing process and a drop.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a polymer electrolyte lithium secondary battery according to the present invention.

FIG. 2 is a perspective view showing a laminated unit cell portion of FIG. 1;

FIG. 3 is an exploded perspective view of the laminated unit cell of FIG. 1;

FIG. 4 is a perspective view showing another embodiment of the spacer used in the polymer electrolyte lithium secondary battery of the present invention.

[Explanation of symbols]

1 ₁ to 1 ₃ ... unit cell, 2 ... positive electrode, 3 ... lithium ion conductive polymer electrolyte layer, 4 ... negative electrode, 12 _1, 12 _2, 17 ... spacer 14 ... exterior film.

Claims (1)

[Claims] 1. A positive electrode capable of storing and releasing lithium ions, a lithium ion conductive polymer electrolyte layer, a negative electrode capable of storing and releasing lithium ions, a lithium ion conductive polymer electrolyte layer, and a lithium ion conductive polymer electrolyte layer. A unit in which a positive electrode capable of inserting and extracting can be laminated in this order, and the area of the positive electrode is smaller than those of the electrolyte layer and the negative electrode, and a frame-shaped space is formed in the electrolyte layer portion located around the positive electrode. A polymer electrolyte lithium secondary battery having a structure in which a plurality of cells are stacked, wherein a frame-shaped or U-shaped insulating spacer is disposed between the stacked unit cells.