JP2005285557A - Flat battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a flat battery of uniform quality capable of carrying out control of both liquid retaining amount and battery thickness at the same time. <P>SOLUTION: The manufacturing method of the flat battery comprises the following processes (1) to (6). (1) A process of preparing anode collecting terminal 12 and a cathode collecting terminal 13, and making a winding electrode body 11 of a flat shape with cathodes and anodes laminated with an interposition of separators, (2) a process of arranging a pair of spacers 31 of a given height at either side part of the winding electrode body of the flat shape and inserting a bottom part into the inside of a laminate film folded into two, (3) a process of sealing a top part and one of the side parts of the laminate film, (4) a process of injecting nonaqueous electrolyte from the other side part of the laminate film and sealing the other side parts 21, 26, (5) a process of pressing from a top part of the flat face with a constant pressure, and (6) a process of carrying out final sealing after degassing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thin battery and a method for manufacturing the same, and more particularly, to a thin battery having a uniform and less variation in thickness using a laminate sheath and a method for manufacturing the same.

  With the rapid spread of portable electronic devices, the required specifications for the batteries used for them are becoming stricter year by year, and in particular, small and thin, high capacity, excellent cycle characteristics, and stable performance are required. Yes. In the field of secondary batteries, lithium non-aqueous electrolyte secondary batteries, which have a higher energy density than other batteries, are attracting attention, and the proportion of lithium non-aqueous electrolyte secondary batteries shows a significant increase in the secondary battery market. ing.

  As shown in FIG. 4, this lithium non-aqueous electrolyte secondary battery is a negative electrode in which a negative electrode active material mixture is applied in a film form on both sides of a negative electrode core (current collector) made of a long sheet-like copper foil or the like. A separator made of a microporous polypropylene film or the like is disposed between the positive electrode in which a positive electrode active material mixture is coated on both sides of a positive electrode core made of a long sheet-like aluminum foil, and the like. After winding the positive electrode in a cylindrical or elliptical shape in a state of being insulated from each other by a separator, in the case of a square battery, the wound electrode body is further crushed to form a flat wound electrode body 11, and the positive electrode and the negative electrode The positive electrode current collector terminal 12 and the negative electrode current collector terminal 13 are connected to the respective predetermined portions of the first and second electrodes, and are housed in a predetermined-shaped exterior (not shown).

  In order to make the lithium non-aqueous electrolyte secondary battery thinner, lighter and bendable, a thin laminated battery (hereinafter referred to as “thin battery”) having a laminated outer package as an outer package has also been developed. (See Patent Documents 1 to 3 below).

  Hereinafter, the manufacturing process of the thin battery 40 conventionally performed conventionally is demonstrated using FIG. First, as shown in FIG. 4, a flat wound electrode body 11 is manufactured in the same manner as in the above-described conventional example. Subsequently, as shown in FIG. 5 (a), a known laminate film 14 of a predetermined size, for example, an aluminum laminate film, is folded in two (cup molding), and the flat wound electrode body 11 is placed therein. After arranging the thin current collecting terminal welding resin materials 15 and 16 on both surfaces of the lead-out portion of the positive current collecting terminal 12 and the negative current collecting terminal 13, the top portion (current collecting terminal side) of the laminate film 14 is heated. Using the bar-shaped mold 17 thus formed, the top sealing portion 18 is formed by controlling the welding in a localized manner. At this time, an unwelded portion 19 is provided at the outer edge of the top sealing portion 18 in order to prevent the sealant layer melted from the laminate film 14 from protruding and adhering to the mold.

  Next, as shown in FIG. 5B, the first side sealing portion 21 is formed by welding one side of the side portion of the laminate film 14 using a heated bar-shaped mold 20. To do. Also in this case, the outer edge of the first side sealing portion 21 is provided with an unwelded portion 22 in order to prevent the sealant layer melted from the laminate film from protruding and adhering to the mold. Next, the liquid electrolyte is injected from the other side portion side. Then, the liquid electrolyte sufficiently penetrates into the flat wound electrode body 11.

  Thereafter, as shown in FIG. 5C, the other side portion side of the laminate film 14 is temporarily welded by a heated bar-shaped mold 23 to form a temporary sealing portion 24. Next, after gelling the liquid electrolyte as necessary, precharging and aging, as shown in FIG. 5 (d), the other side portion side of the laminate film 14 is heated with a bar-shaped mold 25. The second side sealing portion 26 is formed by controlling the orientation method and welding. And the unnecessary part of the said laminate film is cut | disconnected, both the side sealing parts 21 and 26 are bent, and the thin battery 40 of the prior art example as shown in FIG.5 (e) is obtained.

JP 2002-028881 A (paragraphs [0002] to [0013]) JP 2000-268789 A (claims, paragraphs [0015] to [0019], [0023] to [0027]) JP 2000-173641 A (Claims, paragraphs [0017], [0047] to [0048], FIGS. 1 and 5)

  In a thin battery using such a laminate outer package, when the liquid electrolyte is cured into a polymer (gel), the electrode body is placed in the outer package in order to sufficiently infiltrate the electrode body after the liquid electrolyte is injected. In this state, since the electrode is in a swelled state, it is necessary to regulate the thickness by applying a stereotaxic pressure or a constant pressure when the liquid electrolyte is cured.

  In the case of constant pressure pressurization, it is necessary to increase the pressure to some extent in order to control the thickness of the thin battery to a certain thickness. In this case, the thickness of the thin battery can be regulated to a predetermined constant value by increasing the pressure, but at the same time, the liquid electrolyte is pushed out from the electrode body, so that the electrolytic mass existing between the positive electrode and the negative electrode is reduced. Battery characteristics may be degraded.

  On the other hand, in order to regulate the thickness by stereotaxic pressure, it is necessary to deal with each type of thin battery, and thus a large facility is required. In addition, over-compression may occur due to variations in the thickness of the flat wound electrode body. In this case, excessive liquid electrolyte may be pushed out, and the battery characteristics may be reduced as in the case of constant-pressure pressurization. There was sex.

  Further, after the liquid electrolyte has been cured, the side-side sealing portion is brought into a state of being folded into a cup portion into which a flat wound electrode body is inserted in order to minimize the width dimension of the thin battery. It is necessary, but if gel exists in the surplus space between the flat wound electrode body and the laminate film, the surplus gel that protrudes from the gap when the side sealing part is bent rides on the flat wound electrode body. For this reason, the thickness of the battery varies, and the folding position is not stable at the time of folding. Therefore, there is a problem that a metal plate or the like needs to be sandwiched and bent using the plate as a fulcrum. In addition, the above-mentioned point is the problem which arises similarly when using liquid electrolyte as it is, without gelatinizing.

  As a result of repeating various experiments in order to solve the problems of the prior art as described above, the inventor follows the shape of the side portion of the spirally wound electrode body on the side surfaces on both sides of the flat spiral electrode body. It has been found that providing the spacers can solve the above-mentioned problems of the prior art, and the present invention has been completed.

  In Patent Document 3, for the purpose of improving the impact resistance of the thin battery, as shown in FIG. 6, the positive and negative current collecting terminals 52 and 52 of the flat wound electrode body 51 are provided. From the opposite side, resin spacers 54 and 55 having the same shape as the cross section of the flat wound electrode body 51 are arranged, and the flat wound electrode body 51 is enclosed in a laminate film (not shown). Or, as shown in FIG. 7, a laminate film 57 in which a space 56 for accommodating a battery is formed on one surface of the laminate film is used, and a flat wound electrode body 51 is accommodated in the space 56. A thin battery is disclosed in which a laminate film 57 is sealed after filling with a curable resin and then cured, and spacers are disposed on both sides of the flat wound electrode body 51. That is shown It not is.

  In addition, in the thin battery disclosed in Patent Document 3, after applying a liquid electrolyte in which a polymer is dissolved in a solvent in advance to the surfaces of the negative electrode and the positive electrode, the solvent is vaporized to form a gel electrolyte, In other words, there is a step of injecting a liquid electrolyte into the flat wound electrode body 51 disposed in the laminate film. Therefore, the problems of the prior art as described above do not occur.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and a first object thereof is to provide a thin battery having a uniform quality and having a spacer. In addition, the second object of the present invention is to use the spacer to simultaneously control the amount of liquid retained in the flat wound electrode body and the control of the battery thickness, which has been difficult until now, and is uniform. An object of the present invention is to provide a thin battery manufacturing method capable of manufacturing a quality thin battery.

  The first object of the present invention can be achieved by the following configuration. That is, the invention of the thin battery according to claim 1 of the present application is a thin battery comprising a flat wound electrode body in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween, a nonaqueous electrolyte, and a laminate outer package. A spacer having a predetermined height is provided between the side portions on both sides of the flat wound electrode body and the laminate exterior body. In this case, the thin battery is particularly preferable when applied to a lithium nonaqueous electrolyte secondary battery because a thin battery having a small size, light weight, long life, and high output can be obtained.

  The invention according to claim 2 of the present application is the thin battery according to claim 1, wherein the surface of the spacer facing the electrode body has a shape along the shape of the side portion of the electrode body. It is characterized by being. The spacer only needs to be present on the side portion side of the electrode body, and it is optional whether the spacer is disposed on the top portion or the opposite side.

  The invention according to claim 3 of the present application is characterized in that, in the thin battery according to claim 1 or 2, the spacer is made of a material capable of maintaining a shape when a predetermined pressure is applied. .

  The invention according to claim 4 of the present application is the thin battery according to claim 3, wherein the spacer material is a metal that does not react with the non-aqueous electrolyte, a polyolefin such as polypropylene, or an epoxy resin. It is characterized by comprising at least one kind of polymer material such as polyethylene terephthalate resin, polystyrene resin, melamine resin.

  Furthermore, the invention according to claim 5 of the present application is characterized in that, in the thin battery according to any one of claims 1 to 4, the nonaqueous electrolyte is in a gel form.

Furthermore, the second object of the present application can be achieved by the following configuration. That is, the invention of the thin battery manufacturing method according to claim 6 of the present application is characterized by comprising the following steps (1) to (6).
(1) A step of producing a flat wound electrode body including a positive electrode current collecting terminal and a negative electrode current collecting terminal, wherein the positive electrode and the negative electrode are laminated with a separator interposed therebetween,
(2) A step of inserting a pair of spacers having a predetermined height on both side portions of the flat wound electrode body and inserting the bottom portion into a laminate film folded in half,
(3) A step of sealing the top portion and one side portion of the laminate film,
(4) Injecting a nonaqueous electrolyte from the other side portion of the laminate film, and sealing the other side portion;
(5) a step of pressing at a predetermined constant pressure from above the uneven plane;
(6) A step of performing a final seal after degassing.

  The invention according to claim 7 of the present application is the method for producing a thin battery according to claim 6, wherein the nonaqueous electrolyte in the step (4) is a liquid polymer containing a monomer component and a polymerization initiator. It is an electrolyte precursor, and the step (5) is a step of polymerizing the polymer electrolyte precursor while being pressed from above the uneven plane with a predetermined constant pressure.

  The invention according to claim 8 of the present application is the thin battery manufacturing method according to claim 6 or 7, wherein the surface of the spacer facing the electrode body is the shape of the side portion of the electrode body. What used the shape which followed the shape was used.

  The invention according to claim 9 of the present application is characterized in that in the method of manufacturing a thin battery according to any of claims 6 to 8, the method further comprises a step of bending the side sealing portion.

  By providing the above configuration, the present invention has the following excellent effects. That is, according to the thin battery according to claim 1, since there are spacers of a predetermined height between the side portions on both sides of the flat wound electrode body and the laminate exterior body, the surface of the thin electrode Not only becomes flat, but also has excellent impact resistance.

  According to the thin battery of claim 2, since the surface of the spacer facing the electrode body has a shape along the shape of the side part of the electrode body, the dead space of the side part Can be reduced. Therefore, the generation of surplus electrolyte that does not contribute to the reaction of the battery can be reduced because there is no surplus space, and there is no electrolyte that climbs on the flat wound electrode body even if the sealing part is bent, thereby suppressing variation in thickness. Can do.

  According to the thin battery of claim 3, since the spacer is made of a material that can maintain its shape when a predetermined pressure is applied, a force is applied to the entire flat surface side of the thin battery. However, since the further deformation | transformation is suppressed by presence of a spacer, while being able to maintain fixed thickness, it becomes difficult to damage a thin electrode.

  In addition, according to the thin battery of the fourth aspect, it is possible to easily obtain a spacer that is chemically stable and has a predetermined strength.

  Moreover, according to the thin battery of Claim 5, since electrolyte is a gel form, when a laminate exterior is damaged, it is less likely that liquid leakage occurs.

  Furthermore, according to the method for manufacturing a thin battery according to claim 6, since the thickness is kept constant by the spacer when pressed from above the flat surface with a predetermined constant pressure, the flat wound electrode body is formed. Excessive pressure is not applied, the thickness of the thin electrode can be controlled to be constant, and the amount of liquid retained in the electrode body can be controlled to be constant, so that a thin battery with uniform quality can be manufactured. become.

  In addition, according to the thin battery manufacturing method of claim 7, since the polymer electrolyte precursor can be gelled while the thickness of the thin electrode is controlled to be constant, the electrolytic mass in the flat wound electrode body can be reduced. Can be controlled to a certain level, and a thin battery of uniform quality can be manufactured.

  Moreover, according to the thin battery manufacturing method of claim 8, the thin battery of claim 2 can be easily manufactured.

  Further, according to the thin battery of claim 9, due to the presence of the spacer, when the side sealing portion is bent, it can be easily bent using the spacer as a fulcrum without sandwiching a metal plate or the like. It becomes like this.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. 1 to 3 with reference to FIGS. However, in order to facilitate understanding, the same components as those of the conventional flat battery shown in FIGS. 4 and 5 will be described with the same reference numerals. However, the following examples illustrate the thin battery and the manufacturing method thereof for embodying the technical idea of the present invention, and the present invention is specified to the thin battery and the manufacturing method of this embodiment. And is equally applicable to those included in the technical scope described in the claims.

<Manufacture of flat wound electrode body>
First, the manufacturing method of the flat wound electrode body common to an Example and a comparative example is demonstrated. As an active material used for the positive electrode, a mixture of a certain amount of spinel type lithium manganate typified by LiMn ₂ O ₄ and lithium cobaltate typified by LiCoO ₂ was used. The positive electrode plate is prepared by mixing a predetermined amount of a carbon conductive agent (for example, graphite) with the positive electrode active material and then mixing it with a fluororesin binder (for example, polyvinylidene fluoride) at a certain ratio to obtain a positive electrode mixture. It was applied to both sides of the foil, dried and rolled to obtain an electrode plate. The negative electrode plate is made by mixing a carbon material (for example, flake shaped natural graphite) and a fluororesin-based binder at a certain ratio, coating the both surfaces of the copper foil, rolling it after drying, and forming the electrode plate. .

  And as shown in FIG. 4, while welding the positive electrode current collection terminal 12 to the metal core body foil exposure part applicable to the outermost periphery part of a positive electrode, the metal core body foil exposure part applicable to the outer peripheral part of a negative electrode Also, the negative electrode current collector terminal 13 is welded, and a tape (not shown) made of polyphenylene sulfide is attached to the surfaces of these current collector terminals 12 and 13 for the purpose of protection against short circuit, and then the positive electrode plate and The negative electrode plate was wound into a wound shape through a polyethylene porous separator and crushed to produce a flat wound electrode body 11.

  The thin battery of the example was manufactured as follows. First, a set of polypropylene spacers 31 and 32 having a height of 3.5 mm was prepared and brought into contact with both side portions of the flat wound electrode body 11 as shown in FIG. The pair of spacers 31 and 32 has a shape in which the surface on the side facing the side portion of the flat wound electrode body 11 is formed along the shape of the side portion of the electrode body 11, and the opposite surface is wound. The rotating electrode body 11 extends at a right angle to the flat surface. As a result, there is almost no gap between the spacers 31 and 32 and the flat wound electrode body 11. The spacer is not limited to polypropylene, but is made of a metal that does not react with the non-aqueous electrolyte, or at least one kind of polymer material such as polyolefin, epoxy resin, polyethylene terephthalate resin, polystyrene resin, melamine resin, or the like. It can be appropriately selected and used.

  While the spacers 31 and 32 are kept in contact with both side portions of the flat wound electrode body 11, the flat type of the embodiment is performed through the same steps as the manufacturing method of the flat type electrode of the conventional example shown in FIG. A battery was produced. That is, while the spacers 31 and 32 are kept in contact with both side portions of the flat wound electrode body 11, as shown in FIG. A top sealing portion 18 was formed by sealing the top portion using a bar-shaped mold 17. The total thickness of the aluminum laminate film used was about 0.100 mm, and the thickness of the sealant layer was about 0.030 mm. Next, as shown in FIG. 5B, one side of the aluminum laminate film was sealed using a bar-shaped mold 20 to form a side sealing portion 21.

Thereafter, lithium hexafluorophosphate LiPF ₆ was dissolved at a rate of 1 mol / l in a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed so that the mass ratio was EC: DEC = 3: 7. Thus, an electrolytic solution was prepared. After mixing 1 part by mass of a polymerizable compound such as polypropylene glycol diacrylate represented by the following chemical formula (1) or polypyrylene glycol dimethacrylate represented by the following chemical formula (2) with respect to 15 parts by mass of the electrolytic solution. Then, vinylene carbonate was mixed so as to be 1% by mass, and 5000 ppm of t-butylperoxypivalate was further added as a polymerization initiator to obtain a polymer precursor.

After this polymer precursor is injected into the aluminum outer package containing the previous wound electrode body, the other side portion is sealed with a bar-shaped mold 23 as shown in FIG. The temporary sealing part 24 was formed by this, and left still in an oven at 60 ° C. for 3 hours while regulating the thickness with a constant pressure of 2.94 × 10 ² N (30 kgf) as it was, and the polymer precursor was polymerized and cured. A polymer electrolyte was formed. Thereafter, after degassing and pre-charging, as shown in FIG. 5 (d), the other side portion is sealed with a bar-shaped mold 25 to form a sealing portion 26, and the sealing portion Excess portions 21 and 26 were cut and then folded to complete the thin battery of the example. When the sealing portion was bent, the corners of the spacers 31 and 32 became fulcrums, so that the sealing portion could be easily bent. FIG. 2 shows a schematic front view of the thin battery of this example. The thin battery 10 of this example has a nominal capacity of 830 mAh, and as shown in FIG. 2, almost no excess gel is seen between the flat wound electrode body 11 and the laminate film 14. The gap between the bent sealing portions 21 and 26 and the side surface of the thin battery 10 could be almost eliminated.

(Comparative Example 1)
The thin battery 10a of Comparative Example 1 was prepared in the same manner as the thin battery of the Example, except that the spacer was not attached to the flat wound electrode body. When the polymer electrolyte precursor was thermoset, it was 3.7 mm. A battery was fabricated by regulating the thickness by orientation. A schematic front view of the thin battery of Comparative Example 1 is shown in FIG. In the thin battery 10a of Comparative Example 1, surplus spaces were generated between the four corners of the flat wound electrode body and the laminate film 14, and the surplus gel 34 was present in the interior. When the sealing portions 21 and 26 are folded, the portion where the lower excess gel 34 is present is soft, so it cannot be folded from a certain position as it is. It was possible to bend correctly by pressing a thin plate.

(Comparative Example 2)
The thin battery of Comparative Example 2 was prepared in the same manner as the thin battery of the Example except that the spacer was not attached to the flat wound electrode body, and 2.94 × 10 2 when the polymer electrolyte precursor was thermoset. ^A thin battery was produced while regulating the thickness with a constant pressure of ² N (30 kgf). The schematic front view of the thin battery of Comparative Example 2 is the same as the schematic front view of Comparative Example 1 shown in FIG. 3, and the characteristics when the sealing portions 21 and 26 of Comparative Example 2 obtained are bent. This was the same as that of the thin battery of Comparative Example 1.

<Measurement of battery thickness and electrolyte retention after assembly>
For each of the batteries immediately after assembling in Example, Comparative Example 1 and Comparative Example 2, the thickness of each battery was measured with a micrometer to determine the average value and the minimum and maximum values. Moreover, the electrolyte solution holding | maintenance amount was calculated | required by mass measurement. The results are summarized in Table 1. In addition, in the numerical value of battery thickness, the numerical value outside parenthesis shows an average value, and the numerical value in parenthesis shows a minimum value and a maximum value, respectively.

<Measurement of battery capacity and thickness after cycle test>
First, the batteries of Examples, Comparative Example 1 and Comparative Example 2 were charged at a constant current of 1 It = 830 mA at 25 ° C., and after the battery voltage reached 4.2 V, the constant voltage of 4.2 V was charged. The battery was charged until the charging current reached 30 mA. Thereafter, the battery is discharged at a constant current of 1 It until the battery voltage reaches 2.75 V with a 10-minute rest period, and this charge / discharge cycle is repeated as 300 cycles, and then the battery capacity and battery thickness are determined. The battery capacity and battery thickness at 300 cycles were determined. Furthermore, about the battery which calculated | required the battery capacity and battery thickness at the time of these 300 cycles, the charging / discharging cycle of 200 cycles was added, battery capacity and battery thickness were measured similarly, and the battery capacity and battery thickness at the time of 500 cycles were calculated | required. It was. The results are summarized in Table 1.

  From the results in Table 1, the following can be understood. That is, the thickness of the battery needs to be the battery thickness requested by the customer in consideration of variations, but the thin battery of the embodiment using the spacer can regulate the thickness with the spacer, The variation in thickness is very small, and a thin battery with the desired thickness is obtained. On the other hand, since the thickness of the thin battery of Comparative Example 1 is regulated by the localization, the average value of the thickness of each battery is the same level as in the example, but the thickness variation is that of the example. The result is slightly larger than that. In addition, since the thin battery of Comparative Example 2 does not have a spacer even though the thickness is regulated by constant pressure, the thickness of the battery varies greatly from one battery to another, so the variation is very large. Control is impossible. As a result, it is necessary to apply a pressure that reduces the variation in battery thickness, so that the pressure is set to a high setting, and a battery having a small thickness is produced.

  Moreover, the cause of the variation in battery thickness is that the gel 34 existing in the surplus space runs on the surface of the electrode body when the side sealing portion of the battery is bent. In the thin battery of the example, the gel does not exist in the surplus space due to the spacers 31 and 32, so there is no thickness variation due to this, but in the thin battery of Comparative Examples 1 and 2, the gel 34 exists in the surplus space, so the thickness variation. It becomes a factor of.

  The amount of liquid retained in the battery is larger in the thin battery of Comparative Example 1 than in the Example, but smaller in Comparative Example 2 than in the Example. Further, according to the results of the cycle test, the thin battery of Comparative Example 1 has the same characteristics as those of the examples in both battery capacity and thickness after 300 cycles and 500 cycles. In contrast, the thin battery of Comparative Example 2 has the same capacity and thickness after 300 cycles as those of the Example, but the capacity after 500 cycles is that of Example 1 and Comparative Example 1. It is significantly reduced to about 1/3, and the battery thickness is also greatly increased.

  This indicates that in the thin battery of the example, there is no excessive gel due to the reduction of the excess space by the spacer, and the amount is appropriate for the characteristics. On the other hand, in the thin battery of Comparative Example 1, since the surplus space exists, the liquid retention amount is more than the amount necessary for the characteristics, which leads to a good result of the cycle test. In the thin battery of Comparative Example 2, the amount of liquid retained was smaller than that of the example, but this was because excessive pressure was applied at the time of battery production, so that the electrolyte in the flat wound electrode body was pushed out. The result is less than the required amount. For this reason, the thin battery of Comparative Example 2 shows an abrupt deterioration in characteristics over 300 cycles due to the small amount of liquid retained in the battery.

  From the above results, by using the spacer of the present invention, it is possible to control the battery thickness and the amount of liquid retained, and there is less variation in battery dimensions compared to each comparative example, and a thin battery having excellent charge / discharge characteristics. We were able to make it. In addition, the pressurization device by constant pressure control is simpler and less expensive than the pressurization device by localization control, leading to simplification of equipment and cost reduction, as well as cost reduction effect by reducing the amount of electrolyte used. Arise.

  In the present example, a specific positive electrode active material, a negative electrode active material, a non-aqueous solvent, a monomer, a polymerization initiator, and the like are exemplified. However, the present invention provides a flat wound electrode body, In order to specify the invention, it is necessary to use a spacer having a height of 5 mm and an exterior body made of a laminate film. Can be used.

That is, as the positive electrode active material, not only a mixture of lithium manganate and lithium cobaltate but also a lithium transition metal composite represented by Li _x MO ₂ (where M is at least one of Co, Ni, and Mn). oxide, i.e. _{LiCoO 2, LiNiO 2, LiNi y} Co 1-y O 2 (y = 0.01~0.99), LiMnO 2, LiCo x Mn y Ni z O 2 (x + y + z = 1) or the like, LiMn Spinel type lithium cobalt oxide represented by ₂ O ₄ may be used singly or as a mixture of plural kinds, and a small amount of zirconium (Zr), titanium (Ti), fluorine (F), etc. in the positive electrode active material These different elements may be added.

  In addition, as the negative electrode active material used for the negative electrode, at least one selected from the group consisting of a carbonaceous material capable of inserting and extracting lithium, a siliconaceous material, and a metal oxide may be used. A carbonaceous material that has been graphitized is particularly preferable because of its high capacity.

  Nonaqueous solvents (organic solvents) constituting the nonaqueous electrolyte include not only mixed solvents of EC and DEC, but also carbonates, lactones, ethers, esters, aromatic hydrocarbons, and the like. Carbonates, lactones, ethers, ketones, esters and the like are preferable, and carbonates can be used more suitably.

  Specifically, the carbonates are preferably at least one selected from propylene carbonate (PC), ethylene carbonate (EC), and butylene carbonate (BC) as cyclic carbonates, and chain carbonates (acyclic carbonates). As at least 1 sort (s) chosen from dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) is preferable.

The electrolyte constituting the non-aqueous electrolyte is lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), trifluoromethyl. Lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ) and lithium bistrifluoromethylsulfonylimide [LiN (CF ₃ SO ₂ ) ₂ ] can be used. The amount dissolved in the non-aqueous solvent is preferably 0.5 to 2.0 mol / l.

  These electrolytes are not limited to gelled ones, and liquid electrolytes may be used as they are. Furthermore, it can apply also about what sealed at the time of pressure reduction in the case of sealing.

It is a perspective view which shows the state which has arrange | positioned the spacer in the both sides of the flat winding electrode body in an Example. It is a typical front view of the thin battery of an Example. It is a typical front view of the thin battery of a comparative example. It is a perspective view of the flat winding electrode body of a prior art example. It is a figure explaining the manufacturing process of the thin battery of a prior art example. It is a perspective view of the flat winding electrode body which uses the conventional spacer. It is a figure explaining the manufacturing process of the thin battery which uses the flat winding electrode body of FIG.

Explanation of symbols

10, 10a, 40 Thin battery 11 Flat coiled electrode body 12 Positive current collector terminal 13 Negative current collector terminal 14 Laminate sheath 18 Top sealing portion 21, 26 Side sealing portion 31, 32 Spacer 34 Excess gel

Claims (9)

  In a thin battery comprising a flat wound electrode body in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween, a nonaqueous electrolyte, and a laminate outer body, the side portions on both sides of the flat wound electrode body and the laminate A thin battery characterized in that a spacer having a predetermined height is provided between the exterior body and the exterior body.   2. The thin battery according to claim 1, wherein a surface of the spacer facing the electrode body has a shape along a shape of a side portion of the electrode body.   The thin battery according to claim 1, wherein the spacer is made of a material capable of maintaining a shape when a predetermined pressure is applied.   The spacer material is made of metal that does not react with the nonaqueous electrolyte, or at least one kind of polymer material such as polyolefin such as polypropylene, epoxy resin, polyethylene terephthalate resin, polystyrene resin, or melamine resin. The thin battery according to claim 3.   The thin battery according to claim 1, wherein the nonaqueous electrolyte is in a gel form. A method for producing a thin battery comprising the following steps (1) to (6).
(1) A step of producing a flat wound electrode body including a positive electrode current collecting terminal and a negative electrode current collecting terminal, wherein the positive electrode and the negative electrode are laminated with a separator interposed therebetween,
(2) A step of inserting a pair of spacers having a predetermined height on both side portions of the flat wound electrode body and inserting the bottom portion into a laminate film folded in half,
(3) A step of sealing the top portion and one side portion of the laminate film,
(4) Injecting a nonaqueous electrolyte from the other side portion of the laminate film, and sealing the other side portion;
(5) a step of pressing at a predetermined constant pressure from above the uneven plane;
(6) A step of performing a final seal after degassing.   The nonaqueous electrolyte in the step (4) is a liquid polymer electrolyte precursor containing a monomer component and a polymerization initiator, and the step (5) is performed while pressing at a predetermined constant pressure from the upper part of the flat surface. The method for producing a thin battery according to claim 6, which is a step of polymerizing a polymer electrolyte precursor.   The method for manufacturing a thin battery according to claim 6 or 7, wherein a surface of the spacer facing the electrode body has a shape along a shape of a side portion of the electrode body. Furthermore, the process of bending the said side sealing part is provided, The manufacturing method of the thin battery in any one of Claims 6-8 characterized by the above-mentioned.

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