JP2003077457A - Flat non-aqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat non-aqueous electrolyte secondary battery that has an excellent heavy-load discharge characteristics and a large discharge capacity. SOLUTION: In the flat non-aqueous electrolyte secondary battery, the negative electrode case 5 and the positive electrode case 1 are engaged through an insulation gasket 6 and either one of the case has a sealing structure processed by caulking, and a group of electrodes, which encloses a generating element containing a positive electrode 2, a separator 3 and a negative electrode 4 and a non-aqueous electrolyte and comprises at least three faces of opposing faces of the positive and negative electrodes that opposes via the separator in the cross section in the vertical direction to the flat surface of the battery, is housed, and an electrode composition material having conductivity is exposed at the outside in the horizontal direction of the flat surface of the battery, and the exposed part is connected to the battery case. Since the group of electrodes is constructed by turning back alternately the positive electrode and the negative electrode that are arranged in a state of crossing each other via the separator, a flat non-aqueous electrolyte secondary battery having an excellent heavy-load discharge characteristics, low internal resistance and a large discharge capacity can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat type non-aqueous electrolyte secondary battery, and more particularly to a flat type non-aqueous electrolyte secondary battery having excellent heavy load characteristics and large discharge capacity.

[0002]

2. Description of the Related Art A lithium-containing oxide such as lithium cobalt oxide, lithium nickel oxide, or lithium manganate is used as a positive electrode active material, and a carbonaceous material capable of absorbing and releasing lithium in the negative electrode, or a lithium-containing tin oxide, lithium. Containing silicon oxide, lithium-containing oxide such as lithium titanate, non-aqueous electrolyte such as propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyl lactone. LiClO ₄ , LiPF ₆ , LiB in the solvent
_{F 4, LiCF 3 SO 3,} LiN (CF 3 SO 2) 2, LiN
(C2F ₅ SO ₂₎ is a lithium ion secondary battery using a nonaqueous electrolyte obtained by dissolving a supporting salt such as ₂ have already been put to practical use, mobile phones and notebook PC has been used widely as the main power source.

In recent years, with the miniaturization of the equipment used, further miniaturization of the above-mentioned secondary battery has been required, and in order to meet this demand, the inventors of the present invention have applied for Japanese Patent Application No. 11-2409.
As disclosed in Japanese Patent Application No. 64 and Japanese Patent Application No. 11-241290, a metal negative electrode case also serving as a negative electrode terminal and a metal positive electrode case also serving as a positive electrode terminal are fitted with each other through an insulating gasket. A flat non-aqueous electrolyte secondary battery with a sealed structure in which the negative electrode case is crimped and swaged to form a laminated electrode group in which the current-carrying parts of multiple thin electrodes are welded together, or a strip-shaped electrode is wound. Efficiently store the wound electrode group by devising the current collection structure of the battery case,
Provided is a flat type non-aqueous electrolyte secondary battery that is as small as a conventional coin-shaped battery and has excellent heavy load characteristics comparable to a lithium ion secondary battery such as a cylinder or a prism.

[0004]

By the way, the above-mentioned flat non-aqueous electrolyte secondary battery is a flat type secondary battery having a small battery size, which is larger than a conventional coin type battery using a tablet-shaped electrode from the beginning. The aim is to dramatically improve heavy load characteristics without reducing the discharge capacity per hit as much as possible. As a result, a very good coin type battery was obtained, and the heavy load characteristics were dramatically improved. However, with respect to the discharge capacity, it is undeniable that there is a drawback that the absolute amount is small because the battery is very small as compared with the conventional cylindrical or prismatic lithium ion secondary battery.

The present invention has been made in view of the above situation, and the problem to be solved is to increase the discharge capacity to the limit while maintaining the small size, to be small in size and to have excellent heavy load characteristics, and to improve the discharge capacity. It is to provide a large flat non-aqueous electrolyte secondary battery.

[0006]

SUMMARY OF THE INVENTION In order to increase the capacity of a flat battery, the present inventors have tried to minimize the space other than the electrode group of the battery and utilize the volume effectively. For example, when looking at the cross section of the flat battery in the direction perpendicular to the flat surface, a laminated electrode group was prepared by welding the current-carrying parts of a plurality of thin electrodes proposed in Japanese Patent Application No. 11-240964 into one unit. Is a large volume occupied by the current-carrying part of each thin electrode,
The space inside the battery could not be used effectively. In particular, when the total height of the battery is increased in order to obtain a battery having a large discharge capacity, the current-carrying part connecting the plurality of electrodes has to be long, and it is difficult to effectively use the space in the battery.

When the shape of the electrode group is a wound electrode group as shown in Japanese Patent Application No. 11-241290, the current-carrying part of the electrode can be occupied by the electrode coated with the active substance layer, so that a certain amount of capacitance is required. Although it was possible to increase the number, a space is formed above and below the R portion on the side surface of the electrode group even in the wound electrode group. It is theoretically possible to further increase the discharge capacity by paying attention to this point, and devising the winding method so that the electrode group has a rectangular cross section instead of an oval shape. is there. However, such rectangular winding has been practically difficult for an electrode for a flat secondary battery having a small thickness and a small electrode area.

As a means for solving these problems, the present inventors arranged a sheet-like positive electrode and a negative electrode so as to intersect with each other with a separator interposed therebetween, further stacking the separator on the upper electrode, and then forming the positive and negative electrodes. It has been found that it is effective to store the electrode groups formed by alternately folding back through the separator in the container of the flat battery. According to this method, the formed electrode group is a rectangular parallelepiped, and the positive and negative electrodes forming the electrode group are each composed of one electrode, so that an electrode group is formed by stacking a plurality of electrodes in multiple layers. Unlike the group, it does not have a current-carrying part that connects a plurality of electrodes to each other, so that the shape can be reduced, the space in the battery can be effectively used, and a battery having a large discharge capacity can be obtained.

Further, the battery according to the present invention has a structure in which the electrode group and the battery case collect current simply by bringing the electrode case and the electrode group into contact with each other. However, the electrode groups of the battery of the present invention are alternately arranged. Due to the repulsive action of the folded electrodes, an electrode group having elasticity in the direction perpendicular to the horizontal plane of the flat battery is formed. Therefore, as compared with a battery using a conventional electrode group in which a plurality of electrodes are laminated in multiple layers or an electrode group in which band-shaped electrodes are wound, the adhesion between the electrode group and the battery case is increased, and current can be collected more smoothly. . As a result, a battery having a low internal resistance can be obtained, and the amount of the active substance that can be stored in the battery can be increased. In addition, a battery having a large discharge capacity at the time of discharging a large current can be obtained.

When these electrode groups are actually manufactured, either one or both of the positive and negative electrodes are wrapped in a separator in advance, the electrodes of the other electrodes are arranged so as to intersect with them, and the electrodes are wrapped in a separator. The electrode group may be manufactured by alternately folding back the electrode having the other electrode and the electrode having the other electrode. According to this method, the positive and negative electrodes and the separator can be manufactured more easily than the case where the electrodes are separately arranged and folded back to manufacture the electrodes.

Next, the present inventors expanded the volume occupied by the electrode group in the horizontal direction of the flat battery in order to further increase the discharge capacity of the flat battery using the electrode group formed by the above folding. It was investigated.

In the flat battery developed so far, strip-shaped positive and negative electrodes are used, and after making them orthogonal to each other, the electrodes are folded back to form an electrode group of the flat battery. On the other hand, when the cross section in the horizontal direction was seen, the shape of the electrode was square or rectangular. Since a flat battery such as a coin-shaped battery has a circular cross section, a large space is generated between the circular gasket and the rectangular electrode.

Therefore, the present inventors have further earnestly studied to manufacture an electrode group having a shape that matches the shape of the battery case and the gasket by the above folding method. As a result, if the electrode has a shape in which a plurality of unit surfaces are connected and adjacent unit surfaces in the electrode are symmetrical with respect to a folding line that folds back the electrode when manufacturing the electrode group, It has been found that an electrode can be manufactured by the above folding method even if the electrode does not have a strip shape.

According to this method, even when the cross section of the flat battery in the horizontal direction is viewed, it is possible to form an electrode group having a more complicated shape such as a polygon whose cross section is closer to a circle than a square. This makes it possible to obtain a flat secondary battery having a large discharge capacity.

Regarding the detailed shape of the electrode used in this case, it suffices that a plurality of unit surfaces be connected, and an example is an electrode having a shape in which a plurality of polygons such as a pentagon, a hexagon and an octagon are connected. To be When the area of a square electrode inscribed in a circle is 1, it is about 1.2 times for an inscribed regular pentagon, about 1.3 times for an inscribed regular hexagon, and about 1.4 times for an inscribed regular octagon. The electrode area can be expanded.

Further, the unit surface is not limited to a polygon composed of straight lines, and a surface shape obtained by removing at least four sides around a circle or an ellipse may be used. It is more preferable to use an electrode having a shape in which a plurality of surface shapes obtained by cutting out four sides of a circle or an ellipse with straight lines are connected, because the electrode area can be further enlarged as compared with the above inscribed regular octagon. Further, instead of connecting the four sides of the electrode unit surface with a circular arc, a free curve or a curve and a straight line may be used in combination. The shape of the unit surface that constitutes the electrode does not necessarily have to be a deformed regular polygon or a perfect circle, and for flat batteries with a special shape such as an oval shape, the long side should be adjusted to match the battery shape. It is preferable to use an electrode having a unit surface shape having short sides.

On the other hand, in these electrodes, when a plurality of unit surfaces constituting the electrodes are connected, the plurality of unit surfaces may be directly connected to each other, but an extremely short strip-shaped intermediate portion between adjacent unit surfaces. When the region is provided and used as the connecting portion, the electrodes can be easily folded back when the electrode plate is folded back to manufacture the electrode group. Further, since the strip-shaped connecting portion serves as a folded portion, stress due to folding is not applied to the unit surface of the electrode, and the unit surface can be easily kept flat.
More preferable.

As described above, in the electrode group of the present invention, the metal negative electrode case also serving as the negative electrode terminal and the metal positive electrode case also serving as the positive electrode terminal are fitted through the insulating gasket, and the positive electrode case or The negative electrode case was invented with respect to the performance improvement of the flat type non-aqueous electrolyte secondary battery having a sealing structure that has been crimped by crimping, but the scope of application of the electrode group is not limited to this, and it is not limited to the metal case. The present invention is also applicable to a rectangular non-aqueous electrolyte secondary battery that is laser-welded and sealed, and a flat non-aqueous electrolyte secondary battery that uses a laminate film.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Examples and comparative examples of the present invention will be described in detail below. (Embodiment 1) FIG. 1 is a sectional view of the battery of the present invention in a direction perpendicular to the flat surface, and FIG. 2 is a sectional view of the battery of Embodiment 1 in FIG. In the flat non-aqueous electrolyte secondary battery of FIGS. 1 and 2, 1 is a positive electrode case, 2 is a positive electrode plate, 3 is a separator, 4 is a negative electrode plate, 5 is a negative electrode case, 6 is an insulating gasket, and 7 is an electrode group. is there.

The method of manufacturing the battery of Example 1 will be described below. First, 5 parts by mass of acetylene black and 5 parts by mass of graphite powder as a conductive agent were added to 100 parts by mass of LiCoO ₂ , 5 parts by mass of polyvinylidene fluoride as a binder was added, and diluted and mixed with N-methylpyrrolidone to prepare a slurry. A positive electrode mixture in the form of a strip was obtained. Next, this positive electrode mixture was applied to both sides of a 0.02 mm-thick aluminum foil, which is a positive electrode current collector, by a doctor blade method, and after drying, the electrode thickness was 0.12 m.
A rolling treatment was performed so that the thickness became m, and subsequently, the coated active substance-containing layer was removed from the electrode end on one surface to a portion 13.8 mm, and the aluminum layer was exposed to form a current collector. The obtained electrode was further cut into a strip having a width of 13 mm and a length of 192 mm to obtain a positive electrode plate 2. The area of the positive electrode plate 2 coated with the active substance-containing layer was 48.1 cm on both front and back surfaces.
^{Is 2} .

Next, styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders were added to 100 parts by weight of graphitized mesophase pitch carbon fiber powder.
2.5 parts by mass of each was added, and the mixture was diluted with ion-exchanged water and mixed to obtain a slurry-like negative electrode mixture. The obtained negative electrode mixture was applied to both surfaces of a 0.02 mm-thick copper foil that is a negative electrode current collector, and after drying, a rolling treatment was performed so that the electrode thickness would be 0.12 mm. 13. From the electrode end on one side
Remove the active substance-containing layer applied up to 8 mm,
The copper layer was exposed and used as a current collector. The obtained electrode was further cut into a strip having a width of 13 mm and a length of 192 mm to obtain a negative electrode plate 4. The area coated with the active substance-containing layer of the negative electrode plate 4 was 48.1 cm ² for both front and back surfaces.

Next, the obtained positive and negative electrode plates and a thickness of 25
An electrode group was manufactured using a separator made of a polyethylene microporous film of μm. First, the separator is 13.3m wide
m and a length of 370 mm were cut into strips. Subsequently, the end of the separator 3 is aligned with the back surface of the end having the current collector of the positive electrode plate 2, the separator 3 is folded back at the other end of the positive electrode plate 2, and the part of the positive electrode plate 2 other than the current collector is replaced by the separator 3. Covered. Next, the current collecting part of the positive electrode plate 2 covered with the separator 3 is arranged on a plane so that the bottom surface thereof is arranged, and the negative electrode plate 4 projects the other end of the current collecting part of the negative electrode plate 4 onto the current collecting part of the positive electrode plate 2. It was arranged so as to overlap the above-mentioned surface and be orthogonal to the positive electrode plate 2. After that, the positive electrode plate 2
Was folded back together with the separator covering the positive electrode plate 2 along the edge of the negative electrode plate 4 so as to overlap with the negative electrode plate 4. Next, the negative electrode plate 4 was folded back along the edge surface of the separator 3 and was stacked on the separator 3 covering the positive electrode plate 2. Thereafter, the positive electrode plate 2 and the negative electrode plate 4 covered with the separator 3 were alternately folded back to form an electrode group having positive and negative electrode current collectors on both end faces of the electrode group. The manufactured electrode group had elasticity in the direction perpendicular to the current collecting portion at the electrode end.

After drying the produced electrode group at 85 ° C. for 12 hours, the electrode group was placed so that the negative electrode current collector of the electrode group was in contact with the inner bottom surface of the negative electrode metal case 5 integrated with the insulating gasket 6 having an opening diameter of 20 mm. A non-aqueous electrolyte prepared by dissolving LiBF ₄ as a supporting salt in a ratio of 1.5 mol / l was poured into a solvent in which ethylene carbonate and γ-butyl lactone were mixed in a volume ratio of 1: 2, and the positive electrode collection of the electrode group was performed. While fitting the positive electrode case 1 made of stainless steel so as to be in contact with the electric part and turning it upside down, the negative electrode case 5 is pressed in a direction perpendicular to the flat surface of the flat battery to compress the electrode group inside the battery, The positive electrode case has been swaged to a thickness of 5 mm and a diameter of 24.5 m.
A flat type non-aqueous electrolyte secondary battery of Example 1 was manufactured.

(Embodiment 2) FIG. 3 is a plan view of a positive electrode plate of a flat type non-aqueous electrolyte secondary battery according to Embodiment 2 of the present invention, and FIG.
FIG. 3 is a cross-sectional view in a horizontal direction on a flat surface of a battery using the positive electrode plate of FIG.

In Example 2, instead of the strip-shaped positive electrode plate of the flat non-aqueous electrolyte secondary battery of FIG. 1, a constitutional unit composed of a regular pentagon inscribed in a circle having a diameter of 18.4 mm as shown in FIG. , 10.8 mm in width and 0.45 mm in length via a connecting portion, which is continuous in 14 straight lines. The positive electrode active substance-containing layer coating portion 2b is formed on both surfaces of these constituent units, and Using the positive electrode plate 2 in which the active substance layer of the structural unit is removed on only one side and forming the positive electrode current collector 2c, and using the negative electrode plate cut out in the same manner, regular pentagons are linearly connected in 13 lines through the connecting part. A flat type non-aqueous electrolyte secondary battery of Example 2 was manufactured in the same manner as the battery of Example 1 except that the positive and negative electrodes had a crossing angle of 72 ° when the electrode group 7 was manufactured using a shaped separator. In addition, the coated area of the active substance-containing layer of the positive and negative electrode plates of Example 2 was 5 for both the positive and negative electrodes by combining the front and back surfaces.
It is 5.5 cm ² .

(Embodiment 3) FIG. 5 is a plan view of an electrode plate of a flat type non-aqueous electrolyte secondary battery of embodiment 3 of the present invention. In Example 3, instead of the strip-shaped positive electrode plate of the flat battery of FIG.
A unit consisting of a regular hexagon inscribed in a circle with a diameter of 18.4 mm is linearly connected in 14 lines via a connecting part having a width of 9.3 mm and a length of 0.45 mm, and both sides of these units have a positive electrode effect. Using the positive electrode plate 2 in which the substance-containing layer coating portion 2b is formed and the active substance layer of the constituent unit at the outermost end of the electrode is removed only on one side, and the positive electrode current collector portion 2c is formed, a similarly cut negative electrode plate is used. Example 1 was used, except that a separator having a shape in which regular hexagons are connected in a series of 13 through a connecting portion and linearly connected, and the crossing angle of the positive and negative electrodes when manufacturing an electrode group is 60 °.
A flat non-aqueous electrolyte secondary battery of Example 3 was manufactured in the same manner as the battery of Example 1. The area coated with the active substance-containing layer on the positive and negative electrode plates of Example 3 was 60.
It is 5 cm ² .

(Embodiment 4) FIG. 6 is a plan view of an electrode plate of a flat type non-aqueous electrolyte secondary battery of embodiment 4 of the present invention. In Example 4, instead of the strip-shaped positive electrode plate of the flat battery of FIG.
A unit consisting of a regular octagon inscribed in a circle with a diameter of 18.4 mm has a width of 7 mm and a length of 0.45 mm.
The positive electrode active substance-containing layer coating portion 2b is formed on both sides of these constitutional units in a linear manner, and the active substance layer of the constitutional unit at the end of the electrode is removed on only one side to form a positive electrode current collector 2c.
Was carried out in the same manner as in the battery of Example 1 except that the positive electrode plate 2 having the above-mentioned structure was used, the similarly cut negative electrode plate was used, and a separator having a shape in which a regular octagon was connected in a series of 13 and linearly connected was used. A flat non-aqueous electrolyte secondary battery of Example 4 was manufactured. In addition, the applied area of the active substance-containing layer of the positive and negative electrode plates of Example 4 was 65.8 cm for both the positive and negative electrodes by combining the front and back surfaces.
^{Is 2} .

(Embodiment 5) FIG. 7 is a plan view of an electrode plate of a flat battery according to Embodiment 5 of the present invention, and FIG. 8 is a sectional view of the battery using the positive electrode plate of FIG. is there.

In Example 5, instead of the strip-shaped positive electrode plate of the flat battery shown in FIG. 1, two opposite sides are parallel to each other at a position 8.5 mm from the center on each side of a circle having a diameter of 18.4 mm. The constitutional unit composed of the removed surface shape is linearly connected in 14 rows through a connecting portion having a width of 7 mm and a length of 0.45 mm, and the positive electrode active substance-containing layer coating portion 2b is formed on both surfaces of these constitutional units. Then, the positive electrode plate 2 in which the active substance layer of the structural unit at the end of the electrode is removed only on one surface to form the positive electrode current collector 2c
In the same manner as the battery of Example 1, except that a negative electrode plate that was cut out in the same manner was used, and a separator having a surface shape of the same shape as the electrode constitutional unit through the connecting portion and 13 continuous linear shapes was used. A flat non-aqueous electrolyte secondary battery of Example 5 was manufactured. The area coated with the active substance-containing layer on the positive and negative electrode plates of Example 5 was 69.4 c for both the positive and negative electrodes by combining the front and back surfaces.
m ² .

(Comparative Example 1) FIG. 9 is a sectional view of the battery of Comparative Example 1 in the direction perpendicular to the flat surface, and FIG. 10 is a sectional view of the battery of Comparative Example 1 in the horizontal direction on the flat surface.

9 and 10, 1 is a positive electrode case, 2 is a positive electrode plate, 3 is a separator, 4 is a negative electrode plate, 4a is a negative electrode conducting part, 5 is a negative electrode case, 6 is an insulating gasket, 7
Is an electrode group.

In the battery of Comparative Example 1, the positive and negative electrode plates 2 and 4 have a width of 1
Width 7m in 3mm, 11.4mm long active substance layer coating part
m is a plurality of short-sided flat plates accompanied by current-carrying parts 2a, 4a not coated with the positive electrode plate 2 and the negative electrode plate 4 with the short-sided separator 3 interposed therebetween, and then the positive and negative electrodes A battery of Comparative Example 1 was manufactured in the same manner as in Example 1 except that the laminated electrode group 7 manufactured by bundling plates by resistance welding was used. The total area of the positive and negative electrode plates of Comparative Example 1 coated with the active substance-containing layer was 40.0 cm ^{2 for} both the positive and negative electrodes by combining the front and back surfaces.
Is.

Comparative Example 2 FIG. 11 is a sectional view of the battery of Comparative Example 2 in a direction perpendicular to the flat surface. In the battery of Comparative Example 2, the positive and negative electrode plates 2 and 4 were strip-shaped with a width of 13 mm and a length of 181 mm, the length of the positive and negative electrode current collectors was 15.8 mm, and the positive and negative electrode current collectors were wound around the outer circumference. And, the positive electrode plate 2 and the negative electrode plate 4 are spirally wound with the separator 3 interposed therebetween, and the center portion of the wound electrode has a positive and negative electrode facing portion in the horizontal direction with respect to the flat surface of the flat battery. Pressurize until there is no space,
A wound electrode group was manufactured. A battery was manufactured in the same manner as in Example 1 except that this wound electrode group was used. In addition, 1 is a positive electrode case, 5 is a negative electrode case, 6 is an insulating gasket, and the total area of the positive and negative electrode plates of Comparative Example 1 coated with the active substance-containing layer is 45.0 cm for both the positive and negative electrodes. ²
Is.

The batteries of Examples 1 to 5 and Comparative Examples 1 and 2 manufactured as described above were initially charged for 48 hours at a constant current and a constant voltage of 4.2 V and 5 mA. Then, the internal resistance was measured by an alternating current method of 1 kHz, and further discharged to 3.0 V at a constant current of 50 mA to obtain the discharge capacity. The results are shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, the battery using the electrode group produced by folding the strip-shaped electrodes of Example 1 is a laminate of a plurality of short-sided flat plate electrodes of Comparative Example 1, and the current-carrying parts are welded. The electrode area is larger than that of the battery using the laminated electrode group bundled by the above and the battery using the wound electrode group manufactured by winding the strip-shaped electrode of Comparative Example 2, and the electrode group and the battery are Since the contact with the case is good, the internal resistance is low and the discharge capacity is large.

Further, in Examples 2 to 4 in which the shape of the electrodes forming the electrode group was changed from the strip shape in Example 1 to the shape in which polygons are connected, the discharge capacity increased as the electrode area increased. , And more preferably. The discharge capacity of the battery of Example 4 in which the surface shapes obtained by removing the four sides of the circular electrode shape are continuous is even more preferable.

In the above embodiment of the present invention, the flat non-aqueous solvent secondary battery using the non-aqueous solvent as the non-aqueous electrolyte has been described, but the polymer secondary using the polymer electrolyte as the non-aqueous electrolyte is described. It is naturally applicable to a battery or a solid electrolyte secondary battery using a solid electrolyte, and it is also possible to use a polymer thin film or a solid electrolyte membrane instead of the resin separator. Further, the shape of the battery has been described based on the coin-shaped non-aqueous electrolyte which is sealed by crimping the positive electrode case, but it is also possible to replace the positive and negative electrodes and crimp the negative electrode case. Further, the battery shape does not have to be a coin shape, and can be applied to a flat non-aqueous electrolyte secondary battery having a special shape such as an oval shape.

In addition, although the above-mentioned embodiment has explained the battery using the lithium cobalt oxide as the positive electrode acting substance and the carbonaceous material as the negative electrode acting substance, the present invention focuses on the change of the structure of the battery and the electrode. However, the active substance is not limited to these, and is naturally applicable to a battery using another active substance for the positive electrode and / or the negative electrode.

[0040]

As described above, according to the present invention,
It is possible to provide a flat non-aqueous electrolyte secondary battery with a low internal resistance and a large discharge capacity even in a flat non-aqueous electrolyte secondary battery with extremely excellent heavy load discharge characteristics and a very small battery size. . Therefore, its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is a sectional view of a battery of Example 1 of the present invention in a direction perpendicular to a flat surface.

FIG. 2 is a sectional view of the battery of Example 1 of the present invention in the horizontal direction on the flat surface.

FIG. 3 is a plan view of an electrode plate of a battery of Example 2 of the present invention.

FIG. 4 is a sectional view of a battery of Example 2 of the present invention in a horizontal direction on a flat surface.

FIG. 5 is a plan view of an electrode plate of a battery of Example 3 of the present invention.

FIG. 6 is a plan view of an electrode plate of a battery according to Example 4 of the present invention.

FIG. 7 is a plan view of an electrode plate of a battery of Example 5 of the present invention.

FIG. 8 is a sectional view of a battery of Example 5 of the present invention in a horizontal direction on a flat surface.

9 is a cross-sectional view of a battery of Comparative Example 1 in a direction perpendicular to a flat surface.

FIG. 10 is a cross-sectional view of the battery of Comparative Example 1 in the horizontal direction on the flat surface.

11 is a cross-sectional view of a battery of Comparative Example 2 in a direction perpendicular to a flat surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode case, 2 ... Positive electrode plate, 2a ... Positive electrode conducting part, 2b
... Coating part containing positive electrode active substance-containing layer, 2c ... Positive electrode current collecting part, 3 ...
Separator, 4 ... Negative electrode plate, 4a ... Negative electrode conducting part, 4b ... Negative electrode active substance-containing layer coating part, 4c ... Negative electrode current collecting part, 5 ... Negative electrode case, 6 ... Insulating gasket, 7 ... Electrode group.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 10/40 H01M 10/40 Z (72) Inventor Kazuo Udagawa 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo issue Toshiba battery Co., Ltd. in the F-term (reference) 5H011 AA03 CC06 GG02 JJ02 5H021 AA01 AA06 BB04 CC17 CC18 5H022 AA09 AA18 CC08 CC21 5H029 AJ03 AJ06 AK03 AL07 AM02 AM03 AM05 AM07 BJ14 BJ15 DJ02 DJ03 DJ05 EJ04 EJ12 5H050 AA02 AA08 AA12 BA17 CA08 CB08 DA19 DA20 EA08 EA23 EA24 FA05 FA06

Claims (8)

[Claims] 1. A negative electrode case made of metal also serving as a negative electrode terminal and a positive electrode case made of metal also serving as a positive electrode terminal are fitted through an insulating gasket, and the positive electrode case or the negative electrode case is swaged by swaging. A positive electrode and a negative electrode when having a sealed structure and including a power generation element including at least a positive electrode, a separator and a negative electrode and a non-aqueous electrolyte in the inside and seeing a cross section in a direction perpendicular to a flat surface of a flat battery. Have at least three positive and negative electrode facing surfaces facing each other through the separator.
The electrode group having more than one surface is housed, and the electrode component having conductivity is exposed on the outer surface of the flat battery of the electrode group in the direction horizontal to the flat surface, and the electrode component is directly or electrically connected to the battery. In a flat non-aqueous electrolyte secondary battery having a structure for collecting current between a battery case which also serves as an electrode group and an external terminal, connected to a case, the electrode group, and a positive electrode arranged so as to cross through a separator and A flat type non-aqueous electrolyte secondary battery, characterized in that the negative electrode is alternately folded back through a separator. 2. The electrode is formed by connecting a plurality of unit surfaces, and adjacent unit surfaces of the electrodes are symmetrical with respect to a folding line when the electrodes are folded back. Item 2. A flat non-aqueous electrolyte secondary battery according to item 1. 3. The flat non-aqueous electrolyte secondary battery according to claim 2, wherein the electrode is formed by connecting a plurality of polygons. 4. The flat non-aqueous electrolyte according to claim 2, wherein the electrode is formed by connecting a plurality of surface shapes in which a circumference of a circle or an ellipse is removed so that at least four sides are formed. Secondary battery. 5. The electrode has at least four sides, and is formed by connecting a plurality of surface shapes in which the four sides are connected by a single line or a plurality of straight lines and / or curved lines. Item 2. A flat nonaqueous electrolyte secondary battery according to item 2. 6. The flat non-aqueous electrolyte secondary battery according to claim 2, wherein an electrode having a shape in which adjacent unit surfaces forming the electrode are connected by a strip-shaped connecting portion is used. 7. The electrode group includes one of positive and negative electrodes wrapped with a separator, the electrode of the other electrode arranged so as to intersect with the electrode, and the electrode wrapped with the separator and the electrode of the other electrode are alternately folded back. The flat non-aqueous electrolyte secondary battery according to claim 1, wherein the flat non-aqueous electrolyte secondary battery is configured as follows. 8. The electrode group includes a positive electrode and a negative electrode in which a plurality of unit surfaces are continuous and adjacent unit surfaces are symmetrical with respect to a boundary between the unit surfaces, and the positive and negative electrodes are separated by a separator. The positive and negative electrodes are arranged so as to intersect with each other, and the boundary between the unit surface and the unit surface forming the electrode is a broken line.
A flat type non-aqueous electrolyte secondary battery provided with an electrode group, which is characterized by being alternately folded back through a separator.