JP2005235414A - Battery equipped with spirally wound electrode group and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery with high productivity and stable quality by reducing stress being applied to metal foil acting as a coil without decreasing insulation resistance and preventing breaking of the foil in spirally winding work. <P>SOLUTION: In the battery equipped with a spirally wound electrode group, at least one of a positive electrode 10 and a negative electrode has an exposure part to which the metal foil is exposed, and an insulating tape 20 having a prescribed width is pasted from the vicinity of a coating end part to the exposure part in at least one portion of the vicinity of the end of an active material coating layer 12. The insulating tape 20 having the prescribed width is formed so as to be thin at the end part, and the insulating tape 20 is formed so as to be thin in a position facing the end part of the active material coating layer 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a battery including a spiral electrode group, and in particular, a positive electrode in which a positive electrode active material is applied to a positive electrode core made of metal foil, and a negative electrode in which a negative electrode active material is applied to a negative electrode core made of metal foil. The present invention relates to a battery including a spiral electrode group wound in such a manner as to face each other via a separator, and a method for manufacturing the same.

In general, a non-aqueous electrolyte secondary battery such as a lithium ion battery is manufactured as follows. That is, a positive electrode active material composed of LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O _4, etc. is mixed with a carbon-based conductive agent and an organic solvent to prepare a slurry or paste, and this is made into a positive electrode core made of aluminum foil or the like. Apply to the body to make a positive electrode. On the other hand, a negative electrode active material made of natural graphite, a binder and the like are dissolved in an organic solvent to prepare a slurry or paste, which is applied to a negative electrode core made of copper foil or the like to produce a negative electrode.

  These positive electrode and negative electrode are overlapped with a separator made of a polyethylene microporous film in between and wound in a spiral shape by a winder, and then the outermost periphery is taped to form a spiral electrode group. Next, after this is crushed as it is or flatly and inserted into the outer can, for example, a negative electrode lead (negative current collector tab) connected to the negative electrode and a negative electrode terminal (the outer can may also serve as) And connecting the positive electrode lead (positive electrode current collecting tab) connected to the positive electrode and the positive electrode terminal. Next, after injecting a non-aqueous electrolyte solution in which an electrolyte salt is added to an organic solvent into the outer can, the lithium ion battery is manufactured by sealing the opening of the outer can.

In the spiral electrode group described above, for example, as shown in Patent Document 1, when the spiral electrode is wound in a spiral shape, such as a boundary portion between a coated region and a non-coated region of the positive electrode active material or the negative electrode active material. In addition, the occurrence rate of a short circuit increases at a portion where the applied pressure is locally increased. For this reason, an insulating tape is stuck on such a part (short circuit assumption position), and the short circuit by a contact with the counter electrode in a short circuit assumption position is prevented beforehand.
JP 2002-42881 A

  By the way, as shown in FIG. 8, the electrode 60 in which the insulating tape 63 is stuck to the boundary part between the application area | region 62a of the active material layer 62 and the non-application | coating area | region (part which the metal foil 61 used as a core is exposed) 62b. When the coil is wound in a spiral shape, as the winding speed increases, the problem that the foil breakage occurs particularly in the A, B, and C portions where the insulating tape 63 in the vicinity of the winding start portion is attached. occured. This is because the A portion and the C portion become the edge portion (end portion) of the insulating tape 63, and therefore the curvature at the time of winding in a spiral shape is reduced and the portion is bent at an acute angle. For this reason, it is considered that stress occurred in the A part and the C part of the metal foil 61 to which the insulating tape 63 was adhered, and the foil breakage occurred in the A part and the C part.

  Further, in the rolling process after the active material layer 62 is applied, the pressing force is increased at the B portion that is the application end portion of the active material layer 62, and therefore the stress at the B portion of the metal foil 61 is particularly large. As a result, stress strain occurs. Then, it is considered that the stress at the time of further spiral winding is added to the B portion of the metal foil 61 in which the stress strain is generated in this way, and the foil breakage occurs in the B portion. For this reason, it is conceivable to make the thickness of the insulating tape as thin as possible so as not to give stress to the sticking part. However, if the thickness of the insulating tape is made too thin, the insulation resistance between the counter electrode is reduced. Short circuit may occur. For this reason, there is a limit in reducing the thickness of the insulating tape.

  Therefore, the present invention has been made in view of the above-described problems, and reduces the addition of stress to the metal foil serving as the core without reducing the insulation resistance. An object of the present invention is to provide a battery in which productivity is improved and quality is stabilized by preventing the foil from being cut when wound on the battery.

  In the present invention, a positive electrode in which a positive electrode active material is applied to a positive electrode core made of a metal foil and a negative electrode in which a negative electrode active material is applied to a negative electrode core made of a metal foil face each other via a separator. In order to achieve the above object, at least one of the positive electrode and the negative electrode is provided with an exposed portion from which the metal foil is exposed and at least in the vicinity of the active material application end portion. In one place, an insulating tape having a predetermined width is pasted from the vicinity of the coating end portion to the exposed portion so that the thickness of the end portion of the insulating tape having the predetermined width or the position facing the coating end portion is reduced. It is characterized by being formed.

  Thus, when the insulating tape formed so that the thickness of the position facing the end or the coating end is reduced from the vicinity of the active material coating end to the exposed portion of the metal foil, It is possible to reduce stress on the metal foil at the site where the thin insulating tape is attached. As a result, it is possible to prevent foil breakage caused by sticking the insulating tape. In this case, it is desirable that at least one location where the insulating tape is adhered is a position extending between the exposed portion and the active material coating end portion formed on the inner side or the outer side of the spiral electrode group. This is because the position between the exposed portion formed on the winding start end side of the spiral electrode group and the active material application end is the most susceptible to stress when the spiral electrode group is wound.

  And in order to set it as the spiral electrode group of such a structure, the active material application | coating process which apply | coats an active material so that the exposed part which this metal foil exposed may be formed in the edge part side of metal foil, and an active material A predetermined width formed so that the thickness of the end portion or the position facing the coating end portion from the vicinity of the coating end portion to the exposed portion is reduced in at least one place near the active material coating end portion coated with And an insulating tape adhering step for adhering the insulating tape.

  Also, an active material application step of applying an active material so as to form an exposed portion where the metal foil is exposed on the end side of the metal foil, and at least one location in the vicinity of the active material application end where the active material is applied An insulating tape for attaching an insulating tape of a predetermined width to the heating tape, and a heating and pressurizing process for heating and pressurizing the insulating tape so that the thickness of the position facing the end or the coating end of the insulating tape is reduced. You may make it provide. Furthermore, the active material application step of applying the active material so as to form an exposed portion where the metal foil is exposed on the end portion side of the metal foil, and the thickness of the end portion or the position facing the application end portion is reduced. A heating and pressurizing step for heating and pressurizing the insulating tape, and an insulating tape adhering step for adhering the heated and pressurized insulating tape to at least one location in the vicinity of the active material application end where the active material is applied. It may be.

  In the spiral electrode group of the present invention, an insulating tape formed so that the thickness of the end portion or the position facing the coating end portion is reduced from the vicinity of the active material coating end portion to the exposed portion of the metal foil. Since it is attached, it is possible to reduce the stress on the metal foil at the part where the thin insulating tape is attached, and it is possible to prevent the foil breakage caused by attaching the insulating tape.

  Hereinafter, a preferred embodiment when the present invention is applied to a lithium ion battery will be described with reference to FIGS. 1 to 7. However, the present invention is not limited to this embodiment, and the present invention is not limited to this embodiment. It is possible to carry out by appropriately changing without changing the purpose. 1 is a diagram schematically showing a positive electrode plate for applying the present invention to a lithium ion battery, FIG. 1 (a) is a front view thereof, and FIG. 1 (b) is a diagram of FIG. 1 (a). It is sectional drawing which shows an AA cross section. FIG. 2 is a cross-sectional view showing a cross section of the main part in a state where an insulating tape is attached to a part of the positive electrode plate of FIG. FIG. 3 is a perspective view schematically showing an insulating tape wound in a roll shape.

  4 is a diagram schematically showing the negative electrode plate, FIG. 4 (a) is a front view thereof, and FIG. 4 (b) is a cross-sectional view showing the AA cross section of FIG. 4 (a). FIG. 5 is a perspective view schematically showing a state where a spiral electrode group is formed by spirally winding a laminate of a positive electrode plate and a negative electrode plate with a separator interposed therebetween. 6 is a view showing a spiral electrode group, FIG. 6 (a) is a cross-sectional view showing a cross section of the spiral electrode group, and FIG. 6 (b) is an enlarged view of the main part of FIG. 6 (a). FIG. FIG. 7 is a cross-sectional view schematically showing a main part of a manufacturing method according to a modification.

1. Positive electrode A positive electrode mixture composed of a positive electrode active material composed of LiCoO ₂ and a carbon-based conductive agent such as acetylene black and graphite, and a polyvinylidene fluoride (PVDF) as a binder into an organic solvent composed of N-methylpyrrolidone. The dissolved binder solution was mixed to obtain a slurry or paste. Apply these slurries or pastes evenly on both sides of the positive electrode core (for example, an aluminum foil with a thickness of 15 μm) 11 by using a die coater, a doctor blade, etc. Thus, a positive electrode active material application plate coated with the active material layer 12 was formed.

  Then, the positive electrode active material application | coating board which apply | coated the positive electrode active material layer 12 was passed in the dryer, and the organic solvent required for slurry or paste preparation was volatilized and removed, and it was made to dry. Next, the dried positive electrode active material-coated plate is rolled by a roll press so that the positive electrode mixture has a packing density of 3.7 g / ml, and then has predetermined dimensions (for example, a width of 56 mm and a length of 630 mm). ) To produce a positive electrode plate 10.

  In this case, when a spiral electrode group, which will be described later, is produced, the positive electrode active material layer 12 is present on the positive electrode core 11 at the innermost peripheral portion and the outermost peripheral portion of the spiral electrode group. The core exposed portions 12a, 12b, 12c, and 12d that are not to be formed are formed. The core exposed portion 12a is a portion arranged inside the core 12 at the innermost peripheral portion of the spiral electrode group, and the active material uncoated region is 20 mm from the inner peripheral end of the positive electrode 10. It is made to become.

  Further, the core exposed portion 12b is a portion disposed outside the core 12 at the innermost peripheral portion of the spiral electrode group, and the active material uncoated region is 5 mm from the inner peripheral end of the positive electrode 10. It is made to become. Furthermore, the core body exposed portions 12c and 12d are portions disposed on the inner and outer sides of the core body 12 at the outermost peripheral portion of the spiral electrode group, and the active material is not exposed from the outer peripheral side end of the positive electrode 10 to 55 mm. It is made to become an application | coating area | region. And the positive electrode current collection tab (positive electrode lead) 13 is welded to the edge part side of the core exposure part 12a.

2. Insulating Tape Next, as shown in FIG. 3, an insulating tape 20 (x1, x2, x3, x4, x5, x6, x7) wound in a roll shape with a predetermined width (for example, 10 mm) was prepared. In this case, as the insulating tape 20 (x1, x2, x3, x4, x5, x6, x7), an ethylene-acrylate copolymer (EEA) is formed on a base material made of 20 μm thick propylene (PP). The paste applied with the thickness of 10 μm is used. Then, as shown in FIG. 2, the insulating tape 20 (x1, x2, x3, x4, x5) is used by using a heating roller so that the thicknesses of the a part, b part, c part and d part are as follows. x6, x7) are molded.

  Here, as shown in FIG. 2, the thickness of the part a (the end part having a width of 0.5 mm attached to the core body 11) is 30 μm, and the part b (the width attached to the core body 11). The thickness of the 0 mm a portion from the end of the a portion to the end of the uncoated region is 30 μm, and the c portion (the portion having a width of 3.0 mm attached to the end of the active material layer 12) is 30 μm. Thus, the insulating tape 20 having a thickness of 25 μm in the d portion (the end portion having a width of 0.5 mm attached to the active material layer 12) was defined as a tape x1. Note that an inclined portion whose thickness decreases from the c portion toward the d portion is formed on the d portion side of the c portion.

  Similarly, the insulating tape 20 in which the thickness of the part a is 30 μm, the thickness of the part b is 30 μm, the thickness of the part c is 30 μm, and the thickness of the part d is 20 μm is referred to as a tape x2. Also in this case, an inclined portion whose thickness decreases from the c portion toward the d portion is formed on the d portion side of the c portion. In addition, an insulating tape 20 having a thickness of a part of 30 μm, a thickness of b part of 30 μm, a thickness of c part of 20 μm, and a thickness of d part of 20 μm was designated as tape x3. In this case, an inclined portion whose thickness decreases from the b portion toward the c portion is formed on the c portion side of the b portion.

  Further, an insulating tape 20 in which the thickness of the part a is 30 μm, the thickness of the part b is 30 μm, the thickness of the part c is 20 μm, and the thickness of the part d is 15 μm is referred to as a tape x4. In this case, an inclined portion that decreases in thickness from the b portion toward the c portion is formed on the c portion side of the b portion, and from the c portion to the d portion on the d portion side of the c portion. In this way, an inclined portion is formed with a reduced thickness.

Also, an insulating tape 20 having a thickness of a part of 20 μm, a thickness of b part of 30 μm, a thickness of c part of 20 μm, and a thickness of d part of 15 μm was designated as tape x5. In this case, an inclined portion having a thickness decreasing from the b portion toward the a portion is formed on the a portion side of the b portion, and from the b portion toward the c portion on the c portion side of the b portion. An inclined portion having a reduced thickness is formed, and an inclined portion having a thickness decreasing from the c portion toward the d portion is formed on the d portion side of the c portion.
Furthermore, the insulating tape 20 in which the thicknesses of the a part, the b part, the c part, and the d part are all 30 μm was defined as a tape x6. Also, the insulating tape 20 in which the thicknesses of the a part, the b part, the c part, and the d part are all 20 μm was designated as a tape x7.

  In addition, as the insulating tape 20 (x1, x2, x3, x4, x5, x6, x7), in addition to the materials described above, propylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate having a thickness of 14 to 30 μm (PAN) etc., such as rubber adhesive, ethylene vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMAA), etc. You may use what applied the paste material so that thickness might be set to 10-15 micrometers.

  The insulating tape 20 (x1, x2) described above is formed at the boundary between the core exposed portion 12a of the positive electrode 10 and the positive electrode active material layer 12 and at the boundary between the core exposed portion 12b and the positive electrode active material layer 12, respectively. , X3, x4, x5, x6, x7) were attached, and these were designated as positive electrodes a, b, c, d, e, x, y. In addition, what stuck the insulating tape x1 was made into the positive electrode a, what stuck the insulating tape x2 was made into the positive electrode b, what stuck the insulating tape x3 was made into the positive electrode c, and what stuck the insulating tape x4 The positive electrode d was a positive electrode e having an insulating tape x5 attached thereto. Moreover, what stuck the insulating tape x6 was made into the positive electrode x, and what stuck the insulating tape x7 was made into the positive electrode y.

3. Negative electrode On the other hand, graphite as a negative electrode active material (specific surface area of about 3.0 m ² / g), carboxymethyl cellulose (CMC) as a thickener, and styrene-butadiene rubber (SBR) as a binder in mass ratio. A negative electrode mixture was prepared by mixing at a ratio of 95: 3: 2. Water was added to the negative electrode mixture and mixed to obtain a slurry. Thereafter, this slurry was applied to both surfaces of a negative electrode current collector 31 made of a copper foil by a doctor blade method or a die coating method to form a negative electrode active material layer 32.

  Next, the negative electrode active material-coated plate after drying was rolled by a roll press, and then cut to have predetermined dimensions (for example, a width of 56 mm and a length of 630 mm) to produce the negative electrode 30. In addition, when the spiral electrode group is manufactured as described later, an uncoated region where the negative electrode active material layer 32 does not exist is formed on both surfaces of the negative electrode 30 disposed on the outermost peripheral portion. A negative electrode current collecting tab 33 is welded to the end side of the first electrode.

4). Spiral electrode group Next, the positive electrode 10 (a, b, c, d, e, x, y) and the negative electrode 30 manufactured as described above are used, and a separator 40 (see FIG. 5) between them. Then, these were wound in a spiral shape by a winder to produce spiral electrode groups A, B, C, D, E, X, and Y, respectively. In this case, the diameter of the winding core (not shown) of the winder is 3 mm, and the winding speed is adjusted to 500 rpm, 1000 rpm, 2000 rpm, 2500 rpm, 3000 rpm, and the spiral electrode groups A, B, C , D, E, X, Y were prepared.

In order to verify whether or not a foil breakage occurred during winding of these spiral electrode groups A, B, C, D, E, X, and Y, after winding, these spiral electrode groups A, B, Each of C, D, E, X, and Y was disassembled to confirm whether or not a foil breakage occurred. As a result, the results shown in Table 1 below were obtained. Table 1 below shows the results when 30 electrode groups A, B, C, D, E, X, and Y are used, and one of the 30 electrode groups is foil. The case where the piece was cut is indicated by a cross, and the case where no piece of the foil was cut is indicated by a mark.

  As is clear from the results in Table 1 above, the spiral electrode group X using the positive electrode x to which the insulating tape 20 (x6) having the thicknesses a, b, c, and d are all 30 μm is attached. In the spiral electrode group Y using the positive electrode y to which the insulating tape 20 (x7) having the thicknesses of all of the parts a, b, c and d is 20 μm, the winding speed is a low speed of 500 rpm. However, it can be seen that a foil breakage occurs, and normal spiral electrode groups X and Y cannot be produced unless winding is performed at a lower speed.

  On the other hand, in the spiral electrode group A using the positive electrode a to which the insulating tape 20 (x1) in which the thickness of the a part, the b part, and the c part is 30 μm and the thickness of the d part is 25 μm, is taken up. However, it is understood that the foil breakage does not occur at 500 rpm, and the foil breakage occurs when the winding speed reaches 1000 rpm. Further, in the spiral electrode group B using the positive electrode b on which the insulating tape 20 (x2) having a thickness of a part, b part, and c part of 30 μm and a thickness of d part of 20 μm is attached, the winding speed However, at 500 rpm and 1000 rpm, the foil breakage does not occur, and when the winding speed is 2000 rpm, the foil breakage occurs.

  Further, in the spiral electrode group C using the positive electrode c to which the insulating tape 20 (x3) having the thickness of the a part and the b part is 30 μm and the thickness of the c part and the d part is 20 μm, the winding speed is However, at 500 rpm, 1000 rpm, and 2000 rpm, the foil breakage does not occur, and when the winding speed is 2500 rpm, the foil breakage occurs. Further, in the spiral electrode group D using the positive electrode d to which the insulating tape 20 (x4) having the thickness of the part a and the part b is 30 μm, the thickness of the part c is 20 μm, and the thickness of the part d is 15 μm is attached. It can be seen that the foil breakage does not occur when the winding speed is 500 rpm, 1000 rpm, 2000 rpm, or 2500 rpm, and the foil breakage occurs when the winding speed is 3000 rpm.

  Furthermore, a spiral using a positive electrode e to which an insulating tape 20 (x5) having a thickness of a part of 20 μm, a thickness of b part of 30 μm, a thickness of c part of 20 μm, and a thickness of d part of 15 μm is attached. In the electrode group E, foil breakage does not occur when the winding speed is 500 rpm, 1000 rpm, 2000 rpm, 2500 rpm, and 3000 rpm. Even if the winding is performed at a high speed of 3000 rpm, a normal spiral electrode group E is obtained. Can be produced.

  This is because, in the portion d where stress is particularly imparted to the aluminum foil serving as the positive electrode core 11, the thickness of the insulating tape 20 in this portion d is reduced from 30 μm to 25 μm, 25 μm to 20 μm, and 20 μm to 15 μm. This is considered to be because stress applied to the aluminum foil to be the positive electrode core 11 is reduced. In addition, in the portion c where stress is easily applied to the aluminum foil serving as the positive electrode core 11 as in the portion d, as the thickness of the insulating tape 20 in the portion c is reduced from 30 μm to 20 μm, the positive electrode core 11 and This is thought to be because stress applied to the resulting aluminum foil is reduced. Further, in the a part where stress is easily applied to the aluminum foil serving as the positive electrode core 11 as in the d part and the c part, as the thickness of the insulating tape 20 of the a part is reduced from 30 μm to 20 μm, the positive electrode core It is considered that the stress applied to the aluminum foil that becomes the body 11 is reduced.

5). In the above-described example, the insulating tape 20 formed in advance so that the thicknesses of the a part, the b part, the c part, and the d part are appropriately different is used. Although the example of sticking to the boundary portion between the positive electrode active material layer 12 and the boundary portion between the core exposed portion 12b and the positive electrode active material layer 12 has been described, the present invention is not limited to this, and various modifications are possible. An example of the modification will be described below.

  First, the positive electrode plate 10 prepared as described above is prepared, and the thickness of the paste material made of ethylene-acrylic acid ester copolymer (EEA) is added to the base material made of propylene (PP) having a thickness of 20 μm. An insulating tape 20 coated to 10 μm was prepared. Thereafter, the insulating tape 20 was attached to the boundary between the core exposed portion 12a and the positive electrode active material layer 12 and the boundary between the core exposed portion 12b and the positive electrode active material layer 12, respectively. .

  Next, as shown in FIG. 7, the first heating jig 51 is provided with a convex part 51a for forming the a part and an inclined part 51b for forming the inclined part on the a part side of the b part. , A mold 50 including a second heating jig 52 provided with a convex portion 52a for forming a d portion is prepared. After heating this shaping | molding die 50 to predetermined | prescribed temperature (for example, 120 degreeC), it aligned and arrange | positioned to the upper part of the positive electrode plate 10 to which the insulating tape 20 was stuck. Thereafter, the mold 50 is pushed down so that the convex portions 51 a and inclined portions 51 b of the first heating jig 51 and the convex portions 52 a of the second heating jig 52 are pressed against predetermined positions of the insulating tape 20. .

  As a result, the portions of the insulating tape 20 where the convex portions 51a and inclined portions 51b of the first heating jig 51 and the convex portions 52a of the second heating jig 52 are pressed are melted, and the thickness of this portion is reduced. It becomes. As a result, after attaching the insulating tape 20 to the positive electrode plate 10, a thin portion can be easily formed at a predetermined portion of the insulating tape 20.

  According to the manufacturing method of this modified example, it is not necessary to use the insulating tape 20 in which the thin portion is formed in advance, so that this type of insulating tape 20 can be obtained at low cost. In addition, since the alignment for attaching the insulating tapes 20 having different thicknesses to predetermined positions becomes easy, a positive electrode plate to which this type of insulating tape 20 is attached can be easily manufactured. .

  In the above-described embodiment, the boundary between the core exposed portion 12a of the positive electrode 10 and the positive electrode active material layer 12, and the boundary between the core exposed portion 12b and the positive electrode active material layer 12, that is, a spiral electrode. Although the example which stuck the insulating tape 20 on the core body exposure parts 12a and 12b by the side of the winding start end of a group was demonstrated, it is not restricted to this, The core body exposure parts 12c and 12d of the positive electrode 10, and the positive electrode active material layer 12 Alternatively, the insulating tape 20 may be attached to the boundary between the negative electrode 30 and the boundary between the core exposed portion of the negative electrode 30 and the negative electrode active material layer 32. Further, when the core exposed portion is formed on the winding start end side of the negative electrode spiral electrode group and the core exposed portion is also formed on the winding start end side of the positive electrode spiral electrode group, these It is desirable to stick an insulating tape to the boundary between each core exposed portion and each active material layer.

  Further, in the above-described embodiment, an example in which graphite is used as a negative electrode active material of a nonaqueous electrolyte battery has been described. However, in addition to graphite, a carbon-based material that can occlude / desorb lithium ions, such as graphite, carbon black, Coke, glassy carbon, carbon fiber, or a fired body thereof is preferable. In addition, an oxide capable of inserting and extracting lithium ions such as silica-based material, tin oxide, and titanium oxide may be used.

Further, in the above-described embodiment, an example has been described using LiCoO ₂ as the positive electrode active material of the nonaqueous electrolyte battery, in addition to LiCoO _2, lithium-containing transition metal compound capable of receiving lithium ion as a guest, for example, LiNiO ₂ LiCoXNi (1-X) O ₂ , LiCrO ₂ , LiVO ₂ , LiMnO ₂ , αLiFeO ₂ , LiTiO ₂ , LiScO ₂ , LiYO ₂ , LiMn ₂ O _4, etc. are preferred, and in particular, LiNiO ₂ , LiCoXNi (1-X It is preferable to use O ₂ alone or in combination of two or more thereof. Further, a conductive polymer such as polyacetylene or polyaniline may be used.

  Furthermore, in the above-described embodiment, an example in which the present invention is applied to a cylindrical battery has been described. However, the present invention is not limited to a cylindrical battery, and is a battery that uses a spiral electrode group and an electrode group that is flattened by crushing it. If it exists, it is possible to apply to batteries of other shapes such as a square. Moreover, in the above-mentioned embodiment, although the example which applies this invention to a lithium ion battery was demonstrated, when using metal foil as a core other than a lithium ion battery, nickel-cadmium storage battery, nickel-hydrogen storage battery, etc. The present invention can also be applied to various types of batteries.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the positive electrode plate for applying this invention to a lithium ion battery, Fig.1 (a) is the front view, FIG.1 (b) shows the AA cross section of Fig.1 (a). It is sectional drawing shown. It is sectional drawing which shows the cross section of the principal part in the state which affixed the insulating tape to a part of positive electrode plate of FIG. It is a perspective view which shows typically the insulating tape wound by roll shape. FIG. 4A is a diagram schematically illustrating a negative electrode plate, FIG. 4A is a front view thereof, and FIG. 4B is a cross-sectional view illustrating a cross section taken along line AA of FIG. It is a perspective view which shows typically the state which rolls what laminated | stacked the positive electrode plate and the negative electrode plate through the separator in the shape of a spiral, and forms a spiral electrode group. FIG. 6A is a view showing a spiral electrode group, FIG. 6A is a cross-sectional view showing a cross section of the spiral electrode group, and FIG. 6B is an enlarged cross-sectional view showing an enlarged main part of FIG. It is. It is sectional drawing which shows typically the principal part of the manufacturing method of a modification. It is sectional drawing which shows the cross section of the principal part in the state which affixed the insulating tape of the prior art example to a part of positive electrode plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10a ... Spiral electrode group, 10 ... Positive electrode plate, 11 ... Positive electrode core (metal foil), 12 ... Positive electrode active material layer, 12a, 12b, 12c, 12d ... Core body exposed part, 13 ... Positive electrode current collection tab, 20 DESCRIPTION OF SYMBOLS Insulation tape, 30 ... Negative electrode plate, 31 ... Negative electrode core (metal foil), 32 ... Negative electrode active material layer, 33 ... Negative electrode current collection tab, 40 ... Separator, 50 ... Mold, 51 ... 1st heating jig , 51a ... convex portion, 51b ... inclined portion, 52 ... second heating jig, 52a ... convex portion

Claims (5)

A spiral in which a positive electrode in which a positive electrode active material is applied to a positive electrode core made of metal foil and a negative electrode in which a negative electrode active material is applied to a negative electrode core made of metal foil are wound so as to face each other via a separator A battery provided with a group of electrode electrodes,
At least one of the positive electrode and the negative electrode has an exposed portion from which the metal foil is exposed, and has a predetermined width from the vicinity of the coating end portion to the exposed portion at at least one location near the active material coating end portion. Insulating tape is affixed,
A battery comprising a spiral electrode group, wherein the battery is formed so that a thickness at a position facing an end portion or an application end portion of the insulating tape having a predetermined width is thinned.   The at least one location where the insulating tape is adhered is a position extending between an exposed portion and an active material application end portion formed on the inside or outside of the winding start end side of the spiral electrode group. A battery comprising the spiral electrode group according to 1. A positive electrode obtained by applying a positive electrode active material to a positive electrode core made of a metal foil and a negative electrode obtained by applying a negative electrode active material to a negative electrode core made of a metal foil were wound in a spiral shape so as to face each other through a separator. A method of manufacturing a battery including a spiral electrode group,
An active material application step of applying an active material so as to form an exposed portion where the metal foil is exposed on the end side of the metal foil;
Formed at least at one location near the active material application end where the active material is applied, so that the thickness of the end or the position facing the application end is reduced from the vicinity of the application end to the exposed portion. A method for producing a battery having a spiral electrode group, comprising: an insulating tape attaching step for attaching an insulating tape having a predetermined width. A positive electrode obtained by applying a positive electrode active material to a positive electrode core made of a metal foil and a negative electrode obtained by applying a negative electrode active material to a negative electrode core made of a metal foil were spirally wound so as to face each other through a separator. A method of manufacturing a battery including a spiral electrode group,
An active material application step of applying an active material so as to form an exposed portion where the metal foil is exposed on the end side of the metal foil;
An insulating tape adhering step of adhering an insulating tape of a predetermined width to at least one location in the vicinity of the active material application end where the active material is applied;
A battery having a spiral electrode group, comprising: a heating and pressing step of heating and pressurizing the insulating tape so that a thickness at a position facing an end portion or an application end portion of the insulating tape is thinned. Production method. A positive electrode obtained by applying a positive electrode active material to a positive electrode core made of a metal foil and a negative electrode obtained by applying a negative electrode active material to a negative electrode core made of a metal foil were wound in a spiral shape so as to face each other through a separator. A method of manufacturing a battery including a spiral electrode group,
An active material application step of applying an active material so as to form an exposed portion where the metal foil is exposed on the end side of the metal foil;
A heating and pressurizing step of heating and pressurizing the insulating tape so that the thickness at the position facing the end or the coating end is reduced;
A spiral electrode group comprising an insulating tape adhering step for adhering the heat-pressed insulating tape to at least one position in the vicinity of an active material application end portion to which the active material is applied. The manufacturing method of the battery provided.

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