JP2010061820A - Nonaqueous secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery with high safety, the safety being achieved by having a structure where expansion and contraction rate upon charging and discharging of a positive electrode plate and that of a negative electrode plate become as close as possible in the nonaqueous secondary battery, stress due to expansion and contraction of the electrode plates upon charging and discharging in the nonaqueous secondary battery is alleviated, and break or buckling of the electrode plate upon charging and discharging is restrained. <P>SOLUTION: In an electrode group 10 structured by winding in a spiral shape the positive electrode plate 4 forming thin portions 3a 3b of positive mixture layers 2a, 2b on a positive electrode collector 1 with positive electrode mixture paint applied on that 1, the negative electrode plate 8 forming negative electrode mixture layers 6a, 6b on a negative electrode collector 5 with negative electrode mixture paint applied on that 5, and a separator 9 interposed between 4 and 8, expansion and contraction rates A, B of the positive electrode plate 4 and expansion and contraction rates C, D of the negative electrode plate 8 are made to be close with each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a non-aqueous secondary battery represented by a lithium ion secondary battery, and more particularly to a non-aqueous secondary battery excellent in safety.

In recent years, lithium ion secondary batteries, which are widely used as power sources for portable electronic devices, use a carbonaceous material capable of occluding and releasing lithium for the negative electrode, and a composite of a transition metal such as LiCoO ₂ and lithium for the positive electrode. An oxide is used as an active material, thereby realizing a lithium ion secondary battery having a high potential and a high discharge capacity. However, with the recent increase in functionality of electronic devices and communication devices, it is desired to further increase the capacity of lithium ion secondary batteries.

  Here, as an electrode plate that is a power generation element for realizing a high-capacity lithium ion secondary battery, an electrode mixture paint obtained by coating each constituent material on both the positive electrode plate and the negative electrode plate is placed on the current collector. After applying and drying, a method of compressing to the specified thickness by pressing or the like is used. By filling and pressing more active material, the active material density becomes higher and further increase in capacity is possible. It becomes.

  Further, an electrode group in which the above-described positive electrode plate and negative electrode plate are sequentially laminated via a separator or spirally wound via a separator is made of a metal such as stainless steel, nickel-plated iron, or aluminum. In a battery case, a non-aqueous electrolyte is poured into the battery case, and then a sealing plate is hermetically fixed to the opening of the battery case to form a lithium ion secondary battery.

  By the way, while increasing capacity of non-aqueous secondary batteries typified by lithium ion batteries, safety measures should be emphasized. In particular, the positive and negative plates are rapidly connected to the non-aqueous secondary battery due to an internal short circuit. There is a strong demand for improvement in the safety of non-aqueous secondary batteries, because there is a risk of excessive temperature rise and thermal runaway. In particular, a large-sized, high-power non-aqueous secondary battery has a high probability of thermal runaway, and thus a device for improving safety, such as reducing the probability of occurrence, is necessary.

  As described above, the cause of the internal short circuit of the non-aqueous secondary battery is that, as shown in FIG. 14 (a), foreign matter is mixed into the non-aqueous secondary battery. The positive electrode plate 23 on which the positive electrode mixture layers 22 a and 22 b are formed and the negative electrode plate 26 on which the negative electrode mixture layers 25 a and 25 b are formed on the negative electrode current collector 24 are wound through a separator 27 to form an electrode group. It is conceivable that the electrode plate is broken or buckled by the stress applied to the electrode plate when the non-aqueous secondary battery is charged and discharged.

  More specifically, when the electrode group 28 is formed by winding in a spiral shape, tensile stress is applied to the positive electrode plate 23, the negative electrode plate 26, and the separator 27, which are constituent elements, and the elongation rate of each constituent element at this time is increased. The difference causes the fracture from the smallest elongation.

  In addition, when a non-aqueous secondary battery is charged / discharged, stress due to expansion / contraction of the electrode plate is applied to the electrode plate, and the positive electrode plate 23, the negative electrode plate 26 or the separator 27 has the lowest elongation rate due to repeated stress due to repeated charge / discharge. Things break preferentially.

For example, as shown in FIG. 14B, when the positive electrode plate 23 cannot follow the elongation of the negative electrode plate 26 during charging, the positive electrode plate 23 breaks (F in the figure). Even if no breakage occurs, as shown in FIG. 14C, the separator 27 is stretched by the buckling of the negative electrode plate 26, thereby generating a portion where the thickness of the separator 27 is reduced (G in the figure).

  Further, when the positive electrode plate 23 or the negative electrode plate 26 is broken before the separator 27, the broken portion of one of the electrode plates breaks through the separator 27 and the positive electrode plate 23 and the negative electrode plate 26 are short-circuited. Due to this short circuit, a large current flows, and as a result, the temperature of the non-aqueous secondary battery rises rapidly, and the non-aqueous secondary battery may run out of heat as described above.

  Therefore, in order to suppress breakage of the positive electrode plate, as shown in FIG. 15, the positive electrode plate 33 with the positive electrode mixture layer formed on both sides and the negative electrode plate 34 with the negative electrode mixture layer applied on both sides, as shown in FIG. In the non-aqueous secondary battery 31 in which the power generation element 32 wound in a flat shape and the non-aqueous electrolyte solution are housed in the battery case 36, the positive electrode combination of the first surface on the inner peripheral side of both surfaces of the positive electrode plate 33 is A method has been proposed in which the agent layer has higher flexibility (higher tensile elongation at break) than the positive electrode mixture layer on the second surface on the back side (see, for example, Patent Document 1).

Further, in order to improve the elongation rate of the electrode plate, a separator 43 is interposed between the positive electrode plate 41 connected to the positive electrode lead 44 and the negative electrode plate 42 connected to the negative electrode lead 45 as shown in FIG. In the non-aqueous secondary battery in which the positive electrode lead 44 is connected to the positive electrode external terminal 46, the negative electrode lead 45 is connected to the battery case 47, and a non-aqueous electrolyte is injected, Before laminating or winding up the negative electrode plate 42 and the separator 43 to be interposed between the two electrodes, the positive electrode plate is heated at a temperature higher than the recrystallization temperature of the binder and lower than its decomposition temperature. There has been proposed a method of heat-treating one or both of the electrode plate 41 and the negative electrode plate 42 (for example, see Patent Document 2).
JP 2007-103263 A Japanese Patent No. 3066161

  However, in the above-described conventional techniques such as making the positive electrode mixture layer on the inner peripheral side of the positive electrode plate more flexible than the outer peripheral side or heat-treating the positive electrode plate, the positive electrode due to bending stress applied to the positive electrode plate when forming the electrode group Although the effect of suppressing the breakage of the plate is exhibited, it is difficult to relieve the stress due to the expansion and contraction of the electrode plate when charging / discharging the nonaqueous secondary battery and to suppress the breakage or buckling of the electrode plate during charge / discharge Had the problem of being.

  In addition, in the prior art of Patent Document 1 described above, two types of positive electrode mixture paints are prepared to be applied to the front and back surfaces of the positive electrode plate, and these two types of positive electrode mixture paints are applied on the positive electrode current collector. Therefore, the process for producing the positive electrode plate becomes complicated.

  In the prior art of Patent Document 2, the positive electrode plate is pressed to a specified thickness and then heat treated and wound to form an electrode group. The positive electrode plate compressed to the specified thickness by this heat treatment causes buckling. The thickness variation of the positive electrode plate before winding becomes large. Furthermore, it may cause a problem such as a large variation in diameter of the wound electrode group.

  The present invention has been made in view of the above-described conventional problems, and is configured so that the degree of expansion and contraction of the positive electrode plate and the negative electrode plate in the non-aqueous secondary battery is close to each other, and the non-aqueous secondary battery is charged / discharged. An object of the present invention is to provide a highly safe non-aqueous secondary battery by relieving stress due to expansion and contraction of the electrode plate and suppressing breakage or buckling of the electrode plate during charging and discharging.

  In order to achieve the above object, the non-aqueous secondary battery of the present invention is a positive electrode current collector comprising a positive electrode mixture paint obtained by kneading and dispersing an active material comprising at least a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium. The negative electrode current collector is prepared by mixing a positive electrode plate having a positive electrode mixture layer deposited thereon and an active material and a binder made of a material capable of holding lithium at least in a dispersion medium. A non-aqueous electrolyte solution and a non-aqueous electrolyte encapsulated in a battery case include an electrode group formed by winding or laminating a porous insulator between a negative electrode plate formed on a negative electrode mixture layer A water-based secondary battery in which at least one of the positive electrode mixture layer and the negative electrode mixture layer is partially provided with a thin portion, or at least one of the positive electrode mixture paint or the negative electrode mixture paint is intermittently provided. Adhere to positive electrode current collector or negative It is characterized in that it has configured to be close to each other to stretch degree during charge and discharge of the positive electrode plate and negative electrode plate by providing the exposed part of the current collector.

  According to the non-aqueous secondary battery of the present invention, at least one of the positive electrode mixture layer and the negative electrode mixture layer is partially provided with a thin portion, or at least one of the positive electrode mixture or the negative electrode mixture paint. The positive electrode during charging / discharging is configured to be close to each other by charging and discharging the positive electrode plate and the negative electrode plate by providing an exposed portion of the positive electrode current collector or the negative electrode current collector. The stress applied to the positive electrode plate or the negative electrode plate due to the difference in expansion and contraction due to the expansion and contraction of the plate and the negative electrode plate can be relieved, and it is possible to suppress breakage or buckling of the electrode plate. It is possible to provide a highly safe non-aqueous secondary battery by suppressing internal short circuit.

  In the first aspect of the present invention, a positive electrode mixture paint obtained by kneading and dispersing at least an active material composed of a lithium-containing composite oxide, a conductive material, and a binder with a dispersion medium is adhered onto a positive electrode current collector. A negative electrode mixture coating material prepared by kneading and dispersing an active material made of a material capable of holding lithium and a binder at least in a dispersion medium is attached onto a negative electrode current collector by forming a positive electrode plate on which a positive electrode mixture layer is formed. A non-aqueous two-electrode assembly comprising a non-aqueous electrolyte and an electrode group formed by winding or laminating a porous insulator between a negative electrode plate having a negative electrode mixture layer formed on an electric body together with a non-aqueous electrolyte solution A secondary battery in which at least one of the positive electrode mixture layer and the negative electrode mixture layer is partially provided with a thin portion, or at least one of the positive electrode mixture paint or the negative electrode mixture paint is intermittently attached. Let positive current collector or negative electrode By providing an exposed portion of the electric conductor, the degree of expansion and contraction of the positive electrode plate and the negative electrode plate is made closer to each other, so that the difference in expansion and contraction due to the expansion and contraction of the positive electrode plate and the negative electrode plate during charging and discharging is reduced. It is possible to relieve the stress applied to the positive electrode plate or the negative electrode plate and suppress internal short circuit due to electrode plate breakage and electrode plate buckling, and to provide a highly safe non-aqueous secondary battery it can.

  In the second invention of the present invention, the thin portion of the positive electrode mixture layer or the negative electrode mixture layer is uniformly provided in the longitudinal direction, thereby providing a stress relaxation effect to the thin portion. The stress applied to the positive electrode plate or the negative electrode plate can be effectively dispersed in the longitudinal direction of the electrode plate, and the breakage or buckling of the electrode plate can be more effectively suppressed.

  In the third invention of the present invention, the thickness of the positive electrode mixture layer or the negative electrode mixture layer is changed stepwise with respect to the winding direction so that the thickness of the positive electrode mixture layer is, for example, Since the width of the thin part is gradually reduced with respect to the winding direction, the stress difference due to the difference in curvature between the start and end of the positive electrode plate can be reduced when the electrode group is configured. It is possible to effectively suppress breakage of the positive electrode plate and buckling of the positive electrode plate in the electrode group.

In the fourth aspect of the present invention, the thickness of the positive electrode mixture layer or the negative electrode mixture layer is changed stepwise with respect to the winding direction by changing the pitch of the thin portion of the positive electrode mixture layer or the negative electrode mixture layer. Since the pitch of the thin part is gradually increased with respect to the winding direction, the stress difference due to the difference in curvature between the start and end of the positive electrode plate can be reduced when the electrode group is configured. It is possible to effectively suppress breakage of the positive electrode plate and buckling of the electrode plate in the electrode group.

  In the fifth aspect of the present invention, the width of the thin portion of the positive electrode / negative electrode mixture layer on the outer peripheral side of the positive electrode plate or negative electrode plate in the wound electrode group and the positive electrode / negative electrode mixture on the inner peripheral side By changing the width of the thin portion of the layer, as an example, the positive electrode mixture layer on the outer peripheral side of the thin portion of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group The stress difference due to the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate can be alleviated by making the width of the part thinner than the width of the thin part, the breakage of the positive electrode plate in the electrode group and the positive electrode plate It becomes possible to suppress buckling effectively.

  In the sixth invention of the present invention, the pitch of the positive electrode / negative electrode mixture layer on the outer peripheral side of the positive electrode plate or negative electrode plate in the wound electrode group and the positive electrode / negative electrode mixture on the inner peripheral side are thin. By changing the pitch of the portion where the thickness of the layer is thin, as an example, the positive electrode mixture layer where the pitch of the portion where the thickness of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group is thin is on the outer peripheral side The stress difference due to the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate can be relaxed by making it narrower than the pitch of the portion where the thickness of the positive electrode plate is thin. It becomes possible to suppress buckling effectively.

In the seventh invention of the present invention, the thin portion of the positive electrode mixture layer or the negative electrode mixture layer is uniformly provided in the longitudinal direction, or the width is changed stepwise in the winding direction, or A combination of two or more of either changing the pitch stepwise with respect to the winding direction, changing the width between the outer circumference and the inner circumference, or changing the pitch between the outer circumference and the inner circumference. Thus, it is possible to bring the positive and negative electrode plates closer together by exerting a stress relaxation effect according to the formation form of the thin portion and adjusting the expansion and contraction degree of the positive electrode plate or the negative electrode plate.

  In the eighth aspect of the present invention, the exposed portion of the positive electrode current collector or the negative electrode current collector is provided uniformly in the longitudinal direction, thereby imparting a stress relaxation effect to the exposed portion, and the positive electrode plate or the negative electrode current collector. The stress applied to the plate can be effectively dispersed in the longitudinal direction of the electrode plate, and the breakage or buckling of the electrode plate can be more effectively suppressed.

  In the ninth aspect of the present invention, the width of the exposed portion of the positive electrode current collector is taken as an example by changing the width of the exposed portion of the positive electrode current collector or the negative electrode current collector stepwise with respect to the winding direction. When the electrode group is configured by gradually reducing the winding direction with respect to the winding direction, the stress difference due to the difference in curvature between the start and end of the positive electrode plate can be reduced. It is possible to effectively suppress breakage of the positive electrode plate and buckling of the electrode plate.

  In the tenth aspect of the present invention, the pitch of the exposed portion of the positive electrode current collector is exemplified by changing the pitch of the exposed portion of the positive electrode current collector or the negative electrode current collector stepwise with respect to the winding direction. When the electrode group is configured by widening in a stepwise manner with respect to the winding direction, the stress difference due to the difference in curvature between the start and end of the positive electrode plate can be reduced. It is possible to effectively suppress breakage of the positive electrode plate and buckling of the electrode plate.

  In the eleventh aspect of the present invention, by changing the width of the exposed portion on the outer peripheral side of the positive electrode plate or the negative electrode plate in the wound electrode group and the width of the exposed portion on the inner peripheral side, By making the width of the exposed portion on the inner peripheral side of the positive electrode plate wider than the width of the exposed portion on the outer peripheral side in the electrode group, the stress difference due to the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate can be reduced. It is possible to relax, and it becomes possible to effectively suppress the breakage of the positive electrode plate and the buckling of the positive electrode plate in the electrode group.

In the twelfth aspect of the present invention, by changing the pitch of the exposed portion on the outer peripheral side of the positive electrode plate or the negative electrode plate in the wound electrode group and the pitch of the exposed portion on the inner peripheral side, By making the pitch of the exposed part on the inner peripheral side of the positive electrode plate in the electrode group smaller than the pitch of the exposed part on the outer peripheral side, the stress difference due to the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate can be reduced. It is possible to relax, and it becomes possible to effectively suppress the breakage of the positive electrode plate and the buckling of the positive electrode plate in the electrode group.

  In the thirteenth aspect of the present invention, the exposed portions of the positive electrode current collector or the negative electrode current collector are uniformly provided in the longitudinal direction, or the width is changed stepwise in the winding direction, or the winding is performed. Exposure by changing the pitch stepwise with respect to the direction, changing the width on the outer peripheral side and the inner peripheral side, or changing the pitch on the outer peripheral side and the inner peripheral side. By adjusting the degree of expansion / contraction of the positive electrode plate or the negative electrode plate by exerting a stress relaxation effect according to the formation form of the part, it becomes possible to make the expansion degree of the positive electrode plate and the negative electrode plate closer.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a main part of an electrode group 10 after winding in a non-aqueous secondary battery according to an embodiment of the present invention. In the figure, an electrode group 10 for a non-aqueous secondary battery according to the present invention includes a positive electrode plate 4 and a negative electrode composite, in which a positive electrode mixture paint is applied on the positive electrode current collector 1 to form positive electrode mixture layers 2a and 2b. A separator 9 serving as a porous insulator is interposed between the negative electrode plate 8 on which the negative electrode current collector layer 6a, 6b is formed by applying a coating agent on the negative electrode current collector 5, and is wound in a spiral shape. ing.

  Here, in the non-aqueous secondary battery represented by the lithium ion secondary battery of the present invention described above, the negative electrode mixture layer is obtained by intercalating lithium with the negative electrode plate 8 during charging as shown in FIG. 6a, 6b expands the negative electrode plate 8 due to expansion, the positive electrode plate 4 expands at this time C, and lithium is deintercalated from the negative electrode plate 8 during discharge, so that the negative electrode mixture layer 6a, As an example of a configuration for bringing the contraction degree B of the negative electrode plate 8 due to the contraction of 6b and the contraction degree D of the positive electrode plate 4 at this time closer to each other, thin portions 3a and 3b are formed on the positive electrode mixture layers 2a and 2b. It is the structure provided uniformly with respect to the longitudinal direction.

  In order to form the positive electrode mixture layers 2a and 2b on the front surface or the back surface of the positive electrode current collector 1 as described above, a positive electrode active material, a conductive material, and a binder are placed in an appropriate dispersion medium, and a planetary mixer, etc. And then kneading while adjusting the viscosity to be optimal for application to the positive electrode current collector 1 such as an aluminum foil to prepare a positive electrode mixture paint.

  Here, as the positive electrode active material, for example, lithium cobaltate and modified products thereof (such as lithium cobaltate in which aluminum or magnesium is dissolved), lithium nickelate and modified products thereof (partially nickel is substituted with cobalt) Composite oxides such as lithium manganate and modified products thereof.

  As the conductive material at this time, for example, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, and various graphites may be used alone or in combination.

  As the binder at this time, for example, polyvinylidene fluoride (PVdF), a modified polyvinylidene fluoride, polytetrafluoroethylene (PTFE), a rubber particle binder having an acrylate unit, and the like can be used. It is also possible to mix an acrylate monomer or an acrylate oligomer having a reactive functional group introduced into the binder.

The positive electrode mixture paint produced as described above is placed on the positive electrode current collector 1 made of, for example, an aluminum foil using a die coater so that the portions 3a and 3b where the thickness of the positive electrode mixture layers 2a and 2b is thin are aligned in the longitudinal direction. After coating and forming the positive electrode mixture layers 2a and 2b so as to be formed in the same manner, they are dried and pressed so as to be compressed to a predetermined thickness, and then slitted to a specified width and length to form a long strip shape. The positive electrode plate 4 is obtained.

  On the other hand, in order to form the negative electrode mixture layers 6a and 6b on the front or back surface of the negative electrode current collector 5, the negative electrode active material and the binder are placed in an appropriate dispersion medium and mixed by a disperser such as a planetary mixer. Disperse and knead while adjusting the viscosity to be optimal for application to the negative electrode current collector 5 such as a copper foil to prepare a negative electrode mixture paint.

  Here, as the negative electrode active material, for example, various natural graphites and artificial graphites, silicon-based composite materials such as silicide, and various alloy composition materials can be used. As the binder at this time, polyvinylidene fluoride and modified products thereof can be used.

  However, from the viewpoint of improving the acceptability of lithium ions, styrene-butadiene copolymer rubber particles (SBR) or a modified product thereof and a cellulose resin including carboxymethyl cellulose (CMC), It is preferable to use a styrene-butadiene copolymer rubber particle or a modified product obtained by adding a small amount of the above cellulose resin.

  After applying the negative electrode mixture paint prepared as described above onto a negative electrode current collector 5 made of, for example, copper foil using a die coater, drying and pressing to compress to a predetermined thickness, Slitting process into the width and length gives the long strip-like negative electrode plate 8.

  Hereinafter, the nonaqueous secondary battery of the present invention using the positive electrode plate 4 and the negative electrode plate 8 described above will be described. FIG. 13 is a perspective view of a cylindrical lithium ion secondary battery 17 as an example of a non-aqueous secondary battery, with a part thereof cut vertically.

  In the cylindrical lithium ion secondary battery 17 of FIG. 13, a positive electrode plate 4 using a composite lithium oxide as an active material and a negative electrode plate 8 using a material capable of holding lithium as an active material are spirally arranged via a separator 9. As a result, the electrode group 10 is produced.

  The electrode group 10 is housed inside the bottomed cylindrical battery case 11 while being insulated from the battery case 11 by the insulating plate 12, while the negative electrode lead 13 led out from the lower part of the electrode group 10 has the battery case 11. The positive electrode lead 14 led out from the upper part of the electrode group 10 is connected to the sealing plate 15 while being connected to the bottom.

  Further, the battery case 11 is filled with a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof after the non-aqueous electrolyte solution (not shown) made of a predetermined amount of a non-aqueous solvent is injected. The opening of the case 11 is crimped inward by bending inward.

  Here, the separator 9 may have any composition that can withstand the usage range of the lithium ion secondary battery, but it is particularly preferable to use a single or composite of microporous films of olefin resins such as polyethylene and polypropylene. . The thickness of the separator 9 is preferably 10 to 25 μm.

The non-aqueous electrolyte at this time can use various lithium compounds such as LiPF ₆ and LiBF ₄ as electrolyte salts. Further, ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC) can be used alone or in combination as a solvent.

Further, in order to form a good film on the positive electrode plate 4 or the negative electrode plate 8 and to ensure the stability at the time of overcharge, vinylene carbonate (VC) and cyclohexylbenzene (CHB), and modified products thereof are used. Is preferred.

  As a first configuration for making the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 close to each other as described above, the electrode plate for a non-aqueous secondary battery of the present invention includes a positive electrode mixture layer 2a, This can be realized by providing the thin portions 3a and 3d uniformly in the longitudinal direction in at least one of 2b or the negative electrode mixture layers 6a and 6b.

  As an example of a specific configuration, in order to form the thin portions 3c and 3d described above in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the length of the positive electrode current collector 1 shown in FIG. The positive electrode mixture layers 2a and 2b described above are produced through a first step in which the thin portions 3c and 3d of the positive electrode mixture layers 2a and 2b are uniformly applied and formed in the longitudinal direction at least in one direction.

  In this first step, the portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b is thin are applied and formed. After the inside of the die manifold is made negative pressure, the pressure is released and the positive electrode mixture paint is re-applied. The timing at the time of discharge is important, and by adjusting the timing accurately, it is possible to uniformly form the portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b is thin in the longitudinal direction.

  Furthermore, after this positive electrode mixture paint is dried, after passing through a second step in which the positive electrode mixture layers 2a and 2b are pressed to a predetermined thickness that is thicker than the thickness of the thinnest portion in the portions 3c and 3d, The thin portions 3c and 3d are uniformly formed in the longitudinal direction at least at one or more locations in the longitudinal direction of the positive electrode plate 4.

  The positive electrode mixture layer 2a, 2b formed uniformly with respect to the longitudinal direction is easily expanded and contracted at the thin portions 3c, 3d, and the stress applied to the positive electrode plate 4 is effectively dispersed in the longitudinal direction. By doing so, the expansion and contraction degrees C and D of the positive electrode plate 4 and the expansion and contraction degrees A and B of the negative electrode plate 8 can be brought close to each other.

  Further, another electrode plate for a non-aqueous secondary battery according to the present invention includes a positive electrode plate 4 or a negative electrode plate 8 as a second configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. This can be realized by stepwise changing the widths of the portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b or the negative electrode mixture layers 6a and 6b is thin in at least one of the winding directions.

  As an example of a specific configuration, as shown in FIG. 3, a thin portion 3c having width W1> W2> W3 in order from the beginning of spreading on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, A thin portion 3d having widths W1> W2> W3 in order from the beginning of rolling in the same phase as the front surface is formed on the back surface in a stepwise manner in the winding direction.

  With this configuration, when the electrode group 10 shown in FIG. 13 is formed by winding in a spiral shape in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding due to the difference in curvature than the negative electrode plate 8 at the end of winding. However, the positive electrode plate 10 in the electrode group 10 is formed by forming the portions 3c and 3d, which are wider than the positive electrode plate 4 at the end of the firing, on the positive electrode plate 4 opposite to the negative electrode plate 8 at the start of the operation. The expansion and contraction of the plate 4 is promoted, and the stress applied to the positive electrode plate 4 is more effectively relaxed.

  In order to form the above-mentioned thin portions 3c and 3d in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, as shown in FIG. 3, it is perpendicular to the longitudinal direction of the positive electrode current collector 1. First, the portions 3c and 3d where the thicknesses of the positive electrode mixture layers 2a and 2b described above are thin are applied to the front and back surfaces in the direction from the start to the width W1> W2> W3 in a stepwise manner in the winding direction. It is produced through the process.

  Next, after the positive electrode mixture paint is dried, a second step is performed in which the positive electrode mixture layers 2a and 2b are pressed to a predetermined thickness that is thicker than the thickness of the thinnest portion in the portions 3c and 3d. The portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b is thin are formed stepwise in the winding direction at least at one or more locations in the longitudinal direction of the positive electrode plate 4.

  Further, another electrode plate for a non-aqueous secondary battery according to the present invention has a third configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. This can be realized by stepwise changing the pitch of the portions 3c, 3d where the thickness of the positive electrode mixture layers 2a, 2b or the negative electrode mixture layers 6a, 6b is thin in at least one of the winding directions.

  As an example of a specific configuration, as shown in FIG. 4, the surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 has a portion 3c having a small thickness formed on a part of the positive electrode mixture layer 2a in order from the beginning. The pitch P1 <P2 <P3, and the back surface is a part of the positive electrode mixture layer 2b, and a portion 3d having the same phase as the surface is thinned in order from the beginning in order of pitch P1 <P2 <P3 with respect to the winding direction. It is formed step by step.

  With this configuration, when the electrode group 10 shown in FIG. 13 is formed by winding in a spiral shape in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding due to the difference in curvature than the negative electrode plate 8 at the end of winding. However, the positive electrode plate 4 in the electrode group 10 is formed by forming the portions 3c and 3d having a thickness smaller than that of the positive electrode plate 4 at the end of the winding on the positive electrode plate 4 at the start of the counter electrode with the negative electrode plate 8 at the start of the operation. 4 is promoted and the stress applied to the positive electrode plate 4 is more effectively relaxed.

  In order to form the above-mentioned thin portions 3c and 3d in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, at least one portion in the longitudinal direction of the positive electrode current collector 1 as shown in FIG. As described above, the first positive electrode mixture layers 2a and 2b are formed by applying the thin portions 3c and 3d in a stepwise manner in the winding direction at intervals of pitch P1 <P2 <P3 in order from the beginning. It is produced through the process.

  Next, after the positive electrode mixture paint is dried, the positive electrode mixture layers 2a and 2b are pressed to a predetermined thickness that is thicker than the thickness of the thinnest portion in the portions 3c and 3d where the thickness is thin. The portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b is thin are formed stepwise in the winding direction at least at one or more locations in the longitudinal direction of the positive electrode plate 4.

  Further, another electrode plate for a non-aqueous secondary battery according to the present invention includes a positive electrode plate 4 of the electrode group 10 or a fourth structure in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made close to each other as shown in FIG. A portion where the thickness of the positive electrode mixture layer 2a or the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 is thin and the width W4 of the thin portion 3c and the positive electrode mixture layer 2b or the negative electrode mixture layer 6b on the inner peripheral side are thin. This can be realized by applying the positive electrode mixture paint and the negative electrode mixture paint so that the width W5 of 3d is different.

  As an example of a specific configuration, as shown in FIG. 5, a portion 3c where the positive electrode mixture layer 2a having a width W4 is thin is formed on the surface of the positive electrode current collector 1, and a positive electrode having a width W5 where W5> W4 on the back surface. The portion 3d where the thickness of the mixture layer 2b is thin is uniformly formed in the longitudinal direction.

  With this configuration, when the electrode group is formed by spirally winding in the E direction, a tensile stress is applied to the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 due to the difference in curvature, and the inner peripheral side Although a compressive stress is applied to the negative electrode mixture layer 6b, the width W5 of the portion 3d where the thickness of the positive electrode mixture layer 2b on the inner peripheral side in the positive electrode plate 4 opposite to the negative electrode mixture layer 6b on the outer peripheral side is thin. Is formed wider than the width W4 of the portion 3c where the thickness of the positive electrode mixture layer 2a on the outer peripheral side is thin, the expansion and contraction of the positive electrode plate 4 is promoted, and the stress applied to the positive electrode plate 4 is more effectively relieved. .

  In order to form the above-mentioned thin portions 3c and 3d in part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, as shown in FIG. A first step in which a portion 3c where the thickness of the agent layer 2a is thin and a portion 3d where the thickness of the positive electrode mixture layer 2b having a width W5 of W5> W4 is thin is applied uniformly to the longitudinal direction on the back surface; It is made after.

  Next, after the positive electrode mixture paint is dried, the positive electrode mixture layers 2a and 2b are pressed to a predetermined thickness that is thicker than the thickness of the thinnest portion in the portions 3c and 3d where the thickness is thin. The width W5 of the portion 3d where the thickness of the positive electrode mixture layer 2b on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is thin is wider than the width W4 of the portion 3c where the thickness of the positive electrode mixture layer 2a on the outer peripheral side is thin. Thus, the thin portions 3c and 3d are uniformly formed in the longitudinal direction.

  In addition, another electrode plate for a non-aqueous secondary battery according to the present invention has a fifth configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. A portion where the positive electrode mixture layer 2a or the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 is thin and the pitch P4 of the portion 3c and the positive electrode mixture layer 2b or the negative electrode mixture layer 6b on the inner peripheral side are thin. This can be realized by applying the positive electrode mixture paint and the negative electrode mixture paint so that the pitch P5 of 3d is different.

  As an example of a specific configuration, as shown in FIG. 6, the portion 3c where the thickness of the positive electrode mixture layer 2a is thin on the surface of the positive electrode current collector 1 is P4 pitch, and the back surface is P5 <P4. A portion 3d where the thickness of the positive electrode mixture layer 2b is thin is uniformly formed in the longitudinal direction.

  With this configuration, when the electrode group is formed by winding in a spiral shape, tensile stress is applied to the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 due to the difference in curvature, and the negative electrode mixture on the inner peripheral side is applied. Although compression stress is applied to the layer 6b, the pitch P5 of the portion 3d where the thickness of the positive electrode mixture layer 2b on the inner peripheral side of the positive electrode plate 4 opposite to the negative electrode mixture layer 6b on the outer peripheral side is thin is set to the outer peripheral side. By forming the positive electrode mixture layer 2a to be narrower than the pitch P4 of the portion 3c where the thickness is small, the expansion and contraction of the positive electrode plate 4 is promoted and the stress applied to the positive electrode plate 4 is more effectively relieved.

  In order to form the above-described thin portions 3c and 3d in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the positive electrode mixture layer 2a is formed on the surface of the positive electrode current collector 1 as shown in FIG. A portion 3c having a small thickness is applied at a pitch of P4, and a portion 3d having a thin thickness of the positive electrode mixture layer 2b is uniformly applied to the longitudinal direction at a pitch P5 of P5 <P4 on the back surface. It is produced through a process.

  Next, after the positive electrode mixture paint is dried, a second step is performed in which the positive electrode mixture layers 2a and 2b are pressed to a predetermined thickness that is thicker than the thickness of the thinnest portion in the portions 3c and 3d. The pitch P5 of the portion 3d where the thickness of the positive electrode mixture layer 2b on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is smaller than the pitch P4 of the portion 3c where the thickness of the positive electrode mixture layer 2a on the outer peripheral side is thin. Thus, the thin portions 3c and 3d are uniformly formed in the longitudinal direction.

Further, another electrode plate for a non-aqueous secondary battery according to the present invention has, as a sixth configuration in which the expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 are made close to each other, as shown in FIG. At least one of the negative electrode mixture layers 6a and 6b is provided with thin portions 3a and 3d uniformly in the longitudinal direction, or at least one of the positive electrode plate 4 and the negative electrode plate 8 as shown in FIG. On the other hand, the width of the portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b or the negative electrode mixture layers 6a and 6b is thin is changed stepwise with respect to the winding direction, or as shown in FIG. Alternatively, the pitch of the portions 3c and 3d where the thickness of the positive electrode mixture layers 2a and 2b or the negative electrode mixture layers 6a and 6b is thin is changed stepwise with respect to the winding direction on at least one of the negative electrode plates 8. As shown in FIG. 5, the positive electrode plate 4 of the electrode group 10 or A portion where the thickness of the positive electrode mixture layer 2a or the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 is thin and the width W4 of the thin portion 3c and the positive electrode mixture layer 2b or the negative electrode mixture layer 6b on the inner peripheral side are thin. The positive electrode mixture and the negative electrode mixture are applied so that the width W5 of 3d is different, or the positive electrode mixture layer 2a on the outer peripheral side of the positive electrode plate 4 or the negative electrode plate 8 of the electrode group 10 as shown in FIG. The positive electrode mixture and the negative electrode mixture are different so that the pitch P4 of the portion 3c where the thickness of the negative electrode mixture layer 6a is thin and the pitch P5 of the portion 3d where the thickness of the positive electrode mixture layer 2b or the negative electrode mixture layer 6b on the inner peripheral side is thin are different. Similarly, any two or more of coating agent coatings may be combined.

  Another electrode plate for a non-aqueous secondary battery according to the present invention includes a positive electrode current collector 1 or a negative electrode current collector as a seventh configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. This can be realized by providing the exposed portions 3a and 3b uniformly in at least one of the electric bodies 5 in the longitudinal direction.

  As an example of a specific configuration, in order to form the exposed portions 3a and 3b of the positive electrode current collector 1 described above in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, as shown in FIG. It is produced through a first step in which the exposed portions 3a and 3b of the positive electrode current collector 1 are uniformly and intermittently applied in the longitudinal direction at least at one or more locations in the longitudinal direction of the current collector 1.

  In this first step, as a method of forming the exposed portions 3a and 3b of the positive electrode current collector 1 by intermittent application, a positive electrode current collector is formed in a direction perpendicular to the longitudinal direction of the positive electrode current collector 1 using a die coater or the like. An intermittent coating system for intermittently forming the exposed portions 3a and 3b of the electric body 1 can be used.

  Further, after the positive electrode mixture paint is dried, the exposed portions 3a and 3b of the positive electrode current collector 1 are provided in at least one place in the longitudinal direction of the positive electrode plate 4 through a second step of pressing to a predetermined thickness. It is uniformly formed in the longitudinal direction.

  By relieving the stress applied to the positive electrode plate 4 by providing the exposed portions 3a and 3b of the positive electrode current collector 1 uniformly formed in the longitudinal direction with the effect of relieving the stress accompanying expansion and contraction, In the same manner as shown in FIG. 1, the expansion / contraction degrees C and D of the positive electrode plate 4 and the expansion / contraction degrees A and B of the negative electrode plate 8 can be made close to each other.

  In addition, an exposed portion (not shown) of the negative electrode current collector 1 is formed on a part of the negative electrode mixture layers 6 a and 6 b in the negative electrode plate 8 to impart an effect of relieving stress accompanying expansion and contraction. By relaxing the applied stress, it is also possible to bring the expansion and contraction degrees C and D of the positive electrode plate 4 close to the expansion and contraction degrees A and B of the negative electrode plate 8.

  In addition, another electrode plate for a non-aqueous secondary battery according to the present invention has a positive current collector 1 or a negative electrode current collector as an eighth configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is close to each other as shown in FIG. This can be realized by changing the width of the exposed portions 3a and 3b of the electric body 5 stepwise with respect to the winding direction.

  As an example of a specific configuration, as shown in FIG. 8, exposure of the positive electrode current collector 1 having the width W1> W2> W3 in order from the start of spreading on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1. The exposed portion 3b of the positive electrode current collector 1 having a width W1> W2> W3 is formed in a stepwise manner in the winding direction in order from the beginning of the portion 3a on the back surface in the same phase as the front surface.

With this configuration, when the electrode group 10 shown in FIG. 12 is formed by spirally winding in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding due to the difference in curvature than the negative electrode plate 8 at the end of winding. However, the exposed portions 3a and 3b of the positive electrode current collector 1 having a wider width than the positive electrode plate 4 at the end of firing are formed on the positive electrode plate 4 at the start of operation opposite to the negative electrode plate 8 at the start of firing. The expansion and contraction of the positive electrode plate 4 in the group 10 is promoted, and the stress applied to the positive electrode plate 4 is more effectively relaxed.

  In order to form the exposed portions 3a and 3b of the positive electrode current collector 1 described above in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the longitudinal direction of the positive electrode current collector 1 as shown in FIG. The first and second exposed portions 3a and 3b of the positive electrode current collector 1 are formed on the front and rear surfaces in the vertical direction by applying intermittently stepwise with respect to the winding direction in order of width W1> W2> W3 from the beginning. It is manufactured through one step.

  Next, after the positive electrode mixture paint is dried, the exposed portions 3a and 3b of the positive electrode current collector 1 are provided in at least one place in the longitudinal direction of the positive electrode plate 4 through a second step of pressing to a predetermined thickness. It is formed stepwise with respect to the winding direction.

  In addition, an exposed portion (not shown) of the negative electrode current collector 1 is formed on a part of the negative electrode mixture layers 6 a and 6 b in the negative electrode plate 8 to impart an effect of relieving stress accompanying expansion and contraction. By relaxing the applied stress, it is also possible to bring the expansion and contraction degrees C and D of the positive electrode plate 4 close to the expansion and contraction degrees A and B of the negative electrode plate 8.

  Further, another electrode plate for a non-aqueous secondary battery according to the present invention has a ninth configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. This can be realized by changing the pitch of the exposed portions 3a and 3b of the positive electrode current collector 1 or the negative electrode current collector 5 stepwise in at least one of the winding directions.

  As an example of a specific configuration, as shown in FIG. 9, the surface perpendicular to the longitudinal direction of the positive electrode current collector 1 has an exposed portion 3a of the positive electrode current collector 1 on a part of the positive electrode mixture layer 2a. The pitch P1 <P2 <P3 in order from the beginning of the firing, with the pitch P1 <P2 <P3 in order and the back surface of the exposed portion 3b of the positive electrode current collector 1 in phase with the surface of a part of the positive electrode mixture layer 2b. Are formed stepwise with respect to the winding direction.

  With this configuration, when the electrode group 10 shown in FIG. 13 is formed by winding in a spiral shape in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding due to the difference in curvature than the negative electrode plate 8 at the end of winding. In other words, the exposed portions 3a and 3b of the positive electrode current collector 1 are formed at a narrower pitch than the positive electrode plate 4 at the end of firing on the positive electrode plate 4 at the start of firing opposite to the negative electrode plate 8 at the beginning of firing. 10, the expansion and contraction of the positive electrode plate 4 is promoted, and the stress applied to the positive electrode plate 4 is more effectively relaxed.

  In order to form the exposed portions 3a and 3b of the positive electrode current collector 1 described above in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, as shown in FIG. 9, the longitudinal direction of the positive electrode current collector 1 The exposed portions 3a and 3b of the positive electrode current collector 1 described above are formed at least at one or more locations by applying intermittently stepwise in the winding direction at intervals of pitch P1 <P2 <P3 from the beginning. It is manufactured through one step.

  Next, after the positive electrode mixture paint is dried, the exposed portions 3a and 3b of the positive electrode current collector 1 are provided in at least one place in the longitudinal direction of the positive electrode plate 4 through a second step of pressing to a predetermined thickness. It is formed stepwise with respect to the winding direction.

  In addition, an exposed portion (not shown) of the negative electrode current collector 1 is formed on a part of the negative electrode mixture layers 6 a and 6 b in the negative electrode plate 8 to impart an effect of relieving stress accompanying expansion and contraction. By relaxing the applied stress, it is also possible to bring the expansion and contraction degrees C and D of the positive electrode plate 4 close to the expansion and contraction degrees A and B of the negative electrode plate 8.

In addition, another electrode plate for a non-aqueous secondary battery according to the present invention has a tenth configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other as shown in FIG. The width W4 of the exposed portion 3a of the positive electrode current collector 1 or negative electrode current collector 5 on the outer peripheral side of the negative electrode plate 8 and the width W5 of the exposed portion 3b of the positive electrode current collector 1 or negative electrode current collector 5 on the inner peripheral side. Can be realized by applying a positive electrode mixture and a negative electrode mixture.

  As an example of a specific configuration, as shown in FIG. 10, the exposed portion 3a of the positive electrode current collector 1 having a width W4 is formed on the surface of the positive electrode current collector 1, and the positive electrode current collector having a width W5 having W5> W4 on the back surface. The exposed portion 3b of the body 1 is uniformly formed in the longitudinal direction.

  With this configuration, when the electrode group is formed by spirally winding in the E direction, a tensile stress is applied to the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 due to the difference in curvature, and the inner peripheral side Although the compressive stress is applied to the negative electrode mixture layer 6b, the width W5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate 4 opposite to the negative electrode mixture layer 6b on the outer peripheral side is set. By forming it wider than the width W4 of the exposed portion 3a of the positive electrode current collector 1 on the outer peripheral side, the expansion and contraction of the positive electrode plate 4 is promoted, and the stress applied to the positive electrode plate 4 is relieved.

  In order to form the above-described exposed portions 3a and 3b of the positive electrode current collector 1 in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, a width W4 is formed on the surface of the positive electrode current collector 1 as shown in FIG. A first step of forming the exposed portion 3a of the positive electrode current collector 1 and the exposed portion 3b of the positive electrode current collector 1 having a width W5 satisfying W5> W4 on the back surface thereof by intermittently applying uniformly in the longitudinal direction. It is made after.

  Next, after the positive electrode mixture paint is dried, the width W5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is passed through a second step of pressing to a predetermined thickness. The exposed portions 3a and 3b of the positive electrode current collector 1 are uniformly formed in the longitudinal direction so that the width W4 is wider than the width W4 of the exposed portion 3a of the positive electrode current collector 1 on the outer peripheral side.

  Note that an exposed portion (not shown) of the negative electrode current collector 1 is formed in a part of the negative electrode mixture layers 6 a and 6 b in the negative electrode plate 8 to suppress the expansion and contraction of the negative electrode plate 8 and to apply stress to the positive electrode plate 4. By relaxing, it is also possible to make the expansion degrees C and D of the positive electrode plate 4 close to the expansion degrees A and B of the negative electrode plate 8.

  In addition, another electrode plate for a non-aqueous secondary battery according to the present invention has an eleventh configuration in which the expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 are close to each other as shown in FIG. The pitch P4 of the exposed portion 3a of the positive electrode current collector 1 or negative electrode current collector 5 on the outer peripheral side of the negative electrode plate 8 and the pitch P5 of the exposed portion 3b of the positive electrode current collector 1 or negative electrode current collector 5 on the inner peripheral side. Can be realized by applying a positive electrode mixture and a negative electrode mixture.

  As an example of a specific configuration, as shown in FIG. 11, the exposed portion 3a of the positive electrode current collector 1 is formed on the surface of the positive electrode current collector 1 with a pitch of P4, and the back surface is collected with a pitch P5 of P5 <P4. The exposed portion 3b of the electric body 1 is formed uniformly with respect to the longitudinal direction.

  With this configuration, when the electrode group is formed by winding in a spiral shape, tensile stress is applied to the negative electrode mixture layer 6a on the outer peripheral side of the negative electrode plate 8 due to the difference in curvature, and the negative electrode mixture on the inner peripheral side is applied. Although compression stress is applied to the layer 6b, the pitch P5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate 4 opposite to the negative electrode mixture layer 6b on the outer peripheral side is set on the outer peripheral side. By forming it narrower than the pitch P4 of the exposed portion 3a of a certain positive electrode current collector 1, the expansion and contraction of the positive electrode plate 4 is promoted, and the stress applied to the positive electrode plate 4 is relieved.

In order to form the above-described exposed portions 3a and 3b of the positive electrode current collector 1 in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the positive electrode current collector 1 has a positive electrode on the surface thereof as shown in FIG. First, the exposed portion 3a of the current collector 1 is formed by intermittently uniformly applying the exposed portion 3b of the positive electrode current collector 1 with respect to the longitudinal direction at a pitch P5 of P4 and P5 <P4 on the back surface. It is produced through the process.

  Next, after the positive electrode mixture paint is dried, the pitch P5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is passed through a second step of pressing to a predetermined thickness. The exposed portions 3a and 3b of the positive electrode current collector 1 are uniformly formed with respect to the longitudinal direction so as to be narrower than the pitch P4 of the exposed portions 3a of the positive electrode current collector 1 on the outer peripheral side.

  Note that an exposed portion (not shown) of the negative electrode current collector 1 is formed in a part of the negative electrode mixture layers 6 a and 6 b in the negative electrode plate 8 to suppress the expansion and contraction of the negative electrode plate 8 and to apply stress to the positive electrode plate 4. By relaxing, it is also possible to make the expansion degrees C and D of the positive electrode plate 4 close to the expansion degrees A and B of the negative electrode plate 8.

  Furthermore, another electrode plate for a non-aqueous secondary battery according to the present invention has a twelfth configuration in which the degree of expansion and contraction of the positive electrode plate 4 and the negative electrode plate 8 is made closer to each other, as shown in FIG. Exposed portions 3a and 3b are uniformly provided in the longitudinal direction on at least one of the current collectors 5, or exposed portions 3a and 3b of the positive electrode current collector 1 or the negative electrode current collector 5 as shown in FIG. Or the exposed portion 3a of the positive electrode current collector 1 or the negative electrode current collector 5 on at least one of the positive electrode plate 4 and the negative electrode plate 8 as shown in FIG. , 3b is changed stepwise with respect to the winding direction, or the positive electrode current collector 1 or the negative electrode current collector on the outer peripheral side of the positive electrode plate 4 or the negative electrode plate 8 of the electrode group 10 as shown in FIG. 5 of the exposed portion 3a and the positive electrode current collector 1 or the negative electrode on the inner peripheral side The positive electrode mixture paint and the negative electrode mixture paint are applied so that the width W5 of the exposed portion 3b of the electric body 5 is different, or is on the outer peripheral side of the positive electrode plate 4 or the negative electrode plate 8 of the electrode group 10 as shown in FIG. The positive electrode composite paint and the positive electrode paint so that the pitch P4 of the exposed portion 3a of the positive electrode current collector 1 or negative electrode current collector 5 and the pitch P5 of the exposed portion 3b of the positive electrode current collector 1 or negative electrode current collector 5 on the inner peripheral side are different. Similarly, any two or more of the negative electrode mixture paints may be applied in combination.

  Hereinafter, as a specific example of the present invention, an example in which thin portions of the positive electrode mixture layer are uniformly provided in the longitudinal direction will be described in more detail with reference to the drawings.

  First, 100 parts by weight of lithium cobaltate as an active material, 2 parts by weight of acetylene black as a conductive material with respect to 100 parts by weight of the active material, and 2 parts by weight of polyvinylidene fluoride as a binder with respect to 100 parts by weight of the active material Was mixed with an appropriate amount of N-methyl-2-pyrrolidone in a double-arm kneader to prepare a positive electrode mixture paint.

  Next, as shown in FIG. 2, the positive electrode mixture paint has a width on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. A portion 3c having a small thickness of 5 mm is formed at an equal pitch, and a portion 3d having a thickness of 5 mm having the same phase as the front surface on the back surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 is formed at an equal pitch in the longitudinal direction. On the other hand, after uniform coating, drying and drying, the thickness of the positive electrode mixture layers 2a and 2b on one side is 100 μm and the thickness of the positive electrode mixture layers 2a and 2b is 3 μm and 3d is 65 μm. A positive electrode plate 4 was prepared.

  Furthermore, the positive electrode plate 4 is pressed so that the total thickness becomes 165 μm, so that the positive electrode mixture layers 2a and 2b on one side have a thickness of 75 μm, and the surface has a width of 5 mm and a thickness of 65 μm. The portion 3c where the thickness of the layer 2a is thin, and the portion 3d where the thickness of the positive electrode mixture layer 2b whose width is 5 mm and thickness is 65 μm in the same phase as the front surface are thin are uniformly formed in the longitudinal direction. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

On the other hand, 100 parts by weight of artificial graphite as the active material of the negative electrode, and 2.5 parts by weight of styrene-butadiene copolymer rubber particle dispersion (solid content 40% by weight) as the binder with respect to 100 parts by weight of the active material ( 1 part by weight in terms of solid content of the binder), 1 part by weight of carboxymethyl cellulose as a thickener with respect to 100 parts by weight of the active material, and an appropriate amount of water, and agitation in a double-arm kneader. An agent paint was prepared.

  Next, as shown in FIG. 2, this negative electrode mixture paint was applied to a negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm, dried, and then negative electrode on one side. A negative electrode plate 8 in which the thickness of the mixture layers 6a and 6b was 110 μm was produced.

  Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 1.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the positive electrode mixture layer 2a has a thin portion 3c on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and the back surface has the same width and phase as the positive electrode mixture layer 2b. By forming the portion 3d uniformly with respect to the longitudinal direction, the positive electrode plate 4 can be easily stretched and the stress applied to the positive electrode plate 4 is effectively dispersed in the longitudinal direction, and the positive electrode mixture layers 2a and 2b It is considered that good battery characteristics could be maintained because the volume change due to expansion and contraction of the negative electrode plate 8 at a position facing the thin portions 3c and 3d could be suppressed.

  In Example 1, the portion 3c where the thickness of the positive electrode mixture layer 2a on the front surface is thin and the portion 3d where the thickness of the positive electrode mixture layer 2b on the back surface is thin are formed in the same phase. It is also possible to form the portions 3c and 3d having a small thickness by shifting them.

  As an embodiment of the present invention, an embodiment in which the width of a portion where the thickness of the positive electrode mixture layer is thin is reduced stepwise with respect to the winding direction will be described with reference to the drawings.

First, as shown in FIG. 3, the same positive electrode mixture paint as in Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. W1 = 5 mm> W2 = 4.5 mm> W3 = 4.0 mm from the beginning of spreading on the surface in the vertical direction, and the positive electrode mixture layer 2a, whose width is successively narrowed, is formed at an equal pitch, and the positive electrode current collector The thickness of the positive electrode mixture layer 2b, in which W1 = 5 mm> W2 = 4.5 mm> W3 = 4.0 mm, and the width of the positive electrode mixture layer 2b are sequentially narrowed from the beginning in the same phase as the front surface on the back surface perpendicular to the longitudinal direction of 1. The portions 3d are provided stepwise in the winding direction at equal pitches, applied, dried, and then the thickness of the positive electrode mixture layers 2a, 2b on one side is 100 μm, and the thickness of the positive electrode mixture layers 2a, 2b The positive electrode plate 4 in which the thickness of the thin portions 3a and 3b is 75 μm is prepared. It was.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, so that the thickness of the positive electrode mixture layers 2a and 2b on one side is 75 μm and the surface has W1 = 5 mm> W2 = 4.5 mm> W3. = 4.0 mm of the positive electrode mixture layer 2 a having a small thickness 3 c, and the back surface of the positive electrode mixture layer 2 b having the same phase as the front surface W 1 = 5 mm> W 2 = 4.5 mm> W 3 = 4.0 mm A thin portion 3d was formed stepwise in the winding direction. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, after applying the negative electrode mixture paint similar to that of Example 1 to the negative electrode current collector 5 made of a tough pitch copper foil (Cu: 99.9%) having a thickness of 10 μm and drying as shown in FIG. A negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced. The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11.

Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 2.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the thin portions 3c, which are narrowed from the beginning in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1, are thinned at equal pitches, and the width is sequentially increased from the beginning in the same phase as the surface. Are formed in a stepwise manner in the winding direction at equal pitches, so that the positive electrode mixture layers 2a and 2b at the beginning of winding and the positive electrode mixture layer 2a at the end of winding are formed. It is considered that the stress difference due to expansion and contraction due to the difference in curvature from 2b could be alleviated and good battery characteristics could be maintained.

In Example 2, the portion 3c where the thickness of the positive electrode mixture layer 2a on the front surface is thin and the portion 3d where the thickness of the positive electrode mixture layer 2b on the back surface is thin are formed in the same phase. It is also possible to form the portions 3c and 3d having a small thickness by shifting them.

  As an embodiment of the present invention, an embodiment in which the pitch of the portion where the thickness of the positive electrode mixture layer is thin is increased stepwise in the winding direction will be described with reference to the drawings.

  First, as shown in FIG. 4, the same positive electrode mixture paint as that of Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. P1 = 20 mm <P2 = 30 mm <P3 = 40 mm pitch from the beginning of spreading a portion 3c where the thickness of the positive electrode mixture layer 2a having a width of 5 mm is thin on the surface in the vertical direction, and with respect to the longitudinal direction of the positive electrode current collector 1 Then, a portion 3d of the positive electrode mixture layer 2b having the same phase as the front surface and a width of 5 mm is thinly provided on the back surface in the vertical direction at a pitch of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm from the start. On the other hand, after being applied stepwise and dried, the thickness of the positive electrode mixture layers 2a, 2b on one side is 100 μm, and the thickness of the portions 3c, 3d where the positive electrode mixture layers 2a, 2b are thin is 75 μm. A positive electrode plate 4 was produced.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, whereby the thickness of the positive electrode mixture layer 2a, 2b on one side is 75 μm and the thickness of the positive electrode mixture layer 2a is 5 mm wide on the surface. The thin portion 3c has a pitch of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm, and the thin portion 3d of the positive electrode mixture layer 2b having the same phase as the front surface and a width of 5 mm on the back surface has a thickness of P1 = 20 mm <P2 = It formed in steps with respect to the winding direction at a pitch of 30 mm <P3 = 40 mm. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 4, the same negative electrode mixture paint as in Example 1 was applied to a negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced. The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11.

Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 3.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the pitch is gradually increased from the beginning of the rolling of the thin portion 3c on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1. By forming a thin portion 3d having the same phase as the front surface on the back surface and gradually increasing the pitch from the beginning and forming it stepwise in the winding direction, the positive electrode mixture layers 2a and 2b at the beginning of winding in the electrode group 10 and It is considered that the stress difference due to expansion and contraction due to the difference in curvature with the positive electrode mixture layers 2a and 2b at the end of rolling can be alleviated, and good battery characteristics can be maintained.

  In Example 3, the portion 3c where the thickness of the positive electrode mixture layer 2a on the front surface is thin and the portion 3d where the thickness of the positive electrode mixture layer 2b on the back surface is thin are formed in the same phase. It is also possible to form the portions 3c and 3d having a small thickness by shifting them.

  As one embodiment of the present invention, the width of the portion where the thickness of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group is thinner than the width of the portion where the thickness of the positive electrode mixture layer on the outer peripheral side is thinner. An embodiment which is also widened will be described with reference to the drawings.

  First, as shown in FIG. 5, the same positive electrode mixture paint as in Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. A portion 3c where the thickness of the positive electrode mixture layer 2a having a width W4 of 5 mm is thin on the surface in the vertical direction at an equal pitch, and a width W5 in the same phase as the surface on the back surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 The positive electrode mixture layer 2b having a thickness of 6 mm is provided with a thin portion 3d at an equal pitch, applied, dried, and then the positive electrode mixture layer 2a, 2b on one side has a thickness of 100 μm, and the positive electrode mixture layer 2a, A positive electrode plate 4 in which the thicknesses of the portions 3c and 3d where the thickness 2b is thin was 75 μm was produced.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, whereby the thickness of the positive electrode mixture layer 2a, 2b on one side is 75 μm and the thickness of the positive electrode mixture layer 2a is 5 mm wide on the surface. A thin portion 3c was formed, and a thin portion 3d of the positive electrode mixture layer 2b having the same phase as the front surface and a width of 6 mm was formed on the back surface. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 5, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced. The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11.

Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected. Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 4.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because a portion 3c where the thickness of the positive electrode mixture layer 2a having a width W4 is thin is formed on the surface of the positive electrode current collector 1, and a portion 3d where the thickness of the positive electrode mixture layer 2b having a width W5 of W5> W4 is thin is formed on the back surface. By forming the electrode group 10 uniformly with respect to the direction, expansion and contraction due to a difference in curvature between the positive electrode mixture layer 2b on the inner peripheral side and the positive electrode mixture layer 2a on the outer peripheral side when the electrode group 10 is configured. It is considered that the stress difference caused by the above can be alleviated and good battery characteristics can be maintained.

  In Example 4, the portion 3c where the thickness of the positive electrode mixture layer 2a on the front surface is thin and the portion 3d where the thickness of the positive electrode mixture layer 2b on the back surface is thin are formed in the same phase. It is also possible to form the portions 3c and 3d having a small thickness by shifting them.

  As an example of the present invention, the pitch of the portion where the thickness of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group is thinner than the pitch of the portion where the thickness of the positive electrode mixture layer on the outer peripheral side is thinner. An embodiment with a narrower width will be described with reference to the drawings.

  First, as shown in FIG. 6, the same positive electrode mixture paint as in Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. The positive electrode mixture layer 2a having a width of 5 mm on the surface in the vertical direction has a thin portion 3c with a pitch P4 of 30 mm, and the positive electrode mixture having a width of 5 mm on the back surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1. The portion 3d where the thickness of the agent layer 2b is thin is provided with a pitch P5 of 15 mm, and after coating and drying, the thickness of the positive electrode mixture layers 2a, 2b on one side is 100 μm and the thickness of the positive electrode mixture layers 2a, 2b The positive electrode plate 4 in which the thicknesses of the thin portions 3c and 3d were 75 μm was produced.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, whereby the thickness of the positive electrode mixture layer 2a, 2b on one side is 75 μm and the thickness of the positive electrode mixture layer 2a is 5 mm wide on the surface. The thin part 3c was formed with a pitch P4 of 30 mm, and the thin part 3d of the positive electrode mixture layer 2b with a width of 5 mm was formed on the back surface with a pitch P5 of 15 mm. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 6, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 5.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because a portion 3c where the thickness of the positive electrode mixture layer 2a is thin on the surface of the positive electrode current collector 1 is a pitch P4, and a portion 3d where the thickness of the positive electrode mixture layer 2b is thin at a pitch P5 where P5 <P4. By forming the electrode group 10 uniformly with respect to the longitudinal direction, expansion is caused by a difference in curvature between the positive electrode mixture layer 2b on the inner peripheral side and the positive electrode mixture layer 2a on the outer peripheral side. It is considered that the stress difference caused by the shrinkage could be relaxed, and good battery characteristics could be maintained.

  In Example 5, the portion 3c where the thickness of the positive electrode mixture layer 2a on the front surface is thin and the portion 3d where the thickness of the positive electrode mixture layer 2b on the back surface is thin are formed with the same width. It is possible to change the width as well.

  As an embodiment of the present invention, an embodiment in which an exposed portion is provided uniformly in the longitudinal direction on a positive electrode current collector will be described with reference to the drawings.

  First, as shown in FIG. 7, the same positive electrode mixture paint as that of Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. An exposed portion 3a having a width of 5 mm is formed on the surface in the vertical direction at an equal pitch, and an exposed portion 3b having the same phase as the surface is formed on the back surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 at an equal pitch. A positive electrode plate 4 was produced in which the thickness of the positive electrode mixture layers 2a, 2b on one side was 100 μm after being provided uniformly in the longitudinal direction, intermittently applied, and dried.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, so that the exposed portion 3a having a thickness of 75 μm on one side and a width of 5 mm on the front surface is formed on the back surface. An exposed portion 3b having the same phase as the surface and a width of 5 mm was uniformly formed in the longitudinal direction. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 7, the same negative electrode mixture paint as in Example 1 was applied to a negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. Later, the active material density was 1.6 g / cc, and the thickness of the negative electrode mixture layers 6a and 6b on one side was 85 μm (porosity 25%). Then, the negative electrode plate 8 was produced by slitting to a specified width of the cylindrical battery.

Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound through a separator 9 made of a polyethylene microporous film having a thickness of 20 μm were produced. The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11.

Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was designated as Example 6.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the exposed portions 3a and 3b are provided uniformly in the longitudinal direction of the positive electrode current collector 1, so that the exposed portions 3a and 3b exhibit the effect of relieving the stress accompanying expansion and contraction, and the positive electrode plate. It is considered that the stress applied to 4 was relaxed, and the degree of expansion / contraction of the positive electrode plate 4 could be brought close to the degree of expansion / contraction of the negative electrode plate 8, and good battery characteristics could be maintained.

  In Example 6, the exposed portion 3a on the front surface and the exposed portion 3b on the back surface are formed in the same phase, but it is also possible to form the exposed portions 3a and 3b by shifting the phase on the front and back surfaces of the positive electrode plate 4. It is. Moreover, although the exposed portion 3a on the front surface and the exposed portion 3b on the back surface are formed at an equal pitch, it is also possible to change the pitch in the longitudinal direction of the front and back surfaces or the same surface.

  Furthermore, in Example 6, it was set as the structure which provided the exposed parts 3a and 3b uniformly with respect to the longitudinal direction of the positive electrode collector 1, However, It is not limited to this, The longitudinal direction of the negative electrode collector 5 is set. It is also possible to provide an exposed portion (not shown) uniformly with respect to the direction.

  As an embodiment of the present invention, an embodiment in which the width of the exposed portion of the positive electrode current collector is reduced stepwise in the winding direction will be described with reference to the drawings.

  First, as shown in FIG. 8, the same positive electrode mixture paint as that of Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil having a thickness of 15 μm (Al purity: 99.85%). The exposed portions 3a of the positive electrode current collector 1 whose widths are successively narrowed such that W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm from the beginning of spreading on the surface in the vertical direction are arranged at an equal pitch, and the positive electrode current collector 1 The exposed portion 3b of the positive electrode current collector 1 whose width is successively narrowed such as W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm from the beginning of spreading in the same phase as the front surface on the back surface perpendicular to the longitudinal direction, etc. A positive electrode plate 4 was produced in which the thickness of the positive electrode mixture layers 2a and 2b on one side became 100 μm after being provided by being applied stepwise in the winding direction at a pitch, and dried.

Next, the positive electrode plate 4 is pressed so that the total thickness becomes 165 μm, so that the positive electrode mixture layers 2a and 2b on one side have a thickness of 75 μm and the surface has W4 = 5 mm> W5 = 4.5 mm> W6. = Exposed portion 3a of positive electrode current collector 1 of 4.0 mm, and exposed portion 3b of positive electrode current collector 1 of W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm in the same phase as the front surface on the back surface It formed in steps with respect to the winding direction. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 8, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu: 99.9%) having a thickness of 10 μm and dried. A negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 7.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the exposed portions 3a of the positive electrode current collector 1 whose width is narrowed sequentially from the beginning of the surface on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1 are spread at an equal pitch and on the back surface in the same phase as the surface. By forming the exposed portion 3b of the positive electrode current collector 1 having a narrow width from the beginning in a stepwise manner at an equal pitch with respect to the winding direction, the electrode mixture 10 and the positive electrode mixture layers 2a and 2b at the start of winding are spread. It is considered that the stress difference due to expansion and contraction due to the difference in curvature with the positive electrode mixture layers 2a and 2b at the end can be relaxed, and good battery characteristics can be maintained.

  In Example 6, the exposed portion 3a of the positive electrode current collector 1 on the front surface and the exposed portion 3a of the positive electrode current collector 1 on the back surface were formed in the same phase, but the positive and negative electrodes were shifted in phase on the front and back surfaces of the positive electrode plate 4. It is also possible to form the exposed portions 3a and 3b of the current collector 1.

  Furthermore, in Example 7, although the width of the exposed portions 3a and 3b of the positive electrode current collector 1 was reduced stepwise with respect to the winding direction, the present invention is not limited to this, and the negative electrode current collector is not limited thereto. It is also possible to provide an exposed portion (not shown) in 5 and to narrow the width of the exposed portion in a stepwise manner in the winding direction.

  As an embodiment of the present invention, an embodiment in which the pitch of the exposed portion of the positive electrode current collector is increased stepwise in the winding direction will be described with reference to the drawings.

First, as shown in FIG. 9, the same positive electrode mixture paint as in Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. A pitch of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm from the beginning of spreading the exposed portion 3a of the positive electrode current collector 1 having a width of 5 mm on the surface in the vertical direction, and perpendicular to the longitudinal direction of the positive electrode current collector 1 The exposed portion 3b of the positive electrode current collector 1 having the same phase as the front surface and a width of 5 mm is provided on the back surface in the direction at a pitch of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm from the start and stepwise with respect to the winding direction. The positive electrode plate 4 in which the thickness of the positive electrode mixture layers 2a and 2b on one side becomes 100 μm after being applied to and dried.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, so that the positive electrode current collector 1 having a thickness of 75 μm on one side and a width of 5 mm on the surface is exposed. The portion 3a has a pitch of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm, and the exposed portion 3b of the positive electrode current collector 1 having the same phase as the front surface and a width of 5 mm on the back surface has P1 = 20 mm <P2 = 30 mm <P3 = It formed in steps with respect to the winding direction at a pitch of 40 mm. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 9, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was designated as Example 8.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the pitch is gradually increased from the beginning of the exposed portion 3a of the positive electrode current collector 1 on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and with respect to the longitudinal direction of the positive electrode current collector 1. Then, the exposed portion 3b of the positive electrode current collector 1 is formed on the back surface in the vertical direction in the same phase as the front surface, and the pitch is gradually increased from the beginning and formed stepwise in the winding direction. It is considered that the stress difference due to expansion and contraction due to the difference in curvature between the positive electrode mixture layers 2a and 2b and the positive electrode mixture layers 2a and 2b at the end of rolling can be alleviated, and good battery characteristics can be maintained. It is done.

In Example 8, the exposed portion 3a of the positive electrode current collector 1 on the front surface and the exposed portion 3b of the positive electrode current collector 1 on the back surface were formed in the same phase. It is also possible to form the exposed portions 3a and 3b of the current collector 1.

  Further, in Example 8, the pitch of the exposed portions 3a and 3b of the positive electrode current collector 1 is gradually increased with respect to the winding direction. However, the present invention is not limited to this, and the negative electrode current collector is not limited thereto. It is also possible to provide an exposed portion (not shown) in 5 and increase the pitch of the exposed portion stepwise in the winding direction.

  As an embodiment of the present invention, the width of the exposed portion of the positive electrode current collector on the inner peripheral side of the positive electrode plate in the spiral electrode group is made wider than the width of the exposed portion of the positive electrode current collector on the outer peripheral side. Examples will be described with reference to the drawings.

  First, as shown in FIG. 10, the same positive electrode mixture paint as that of Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. The exposed portions 3a of the positive electrode current collector 1 having a width W4 of 5 mm are formed on the surface in the vertical direction at an equal pitch, and the back surface perpendicular to the longitudinal direction of the positive electrode current collector 1 is in phase with the surface and the width W5 is 6 mm. A positive electrode plate 4 was prepared in which the exposed portions 3b of the positive electrode current collector 1 were applied at an equal pitch, coated, and dried, and then the thickness of the positive electrode mixture layers 2a, 2b on one side became 100 μm.

  Next, the positive electrode plate 4 is pressed so that the total thickness is 165 μm, whereby the positive electrode current collector layer 1 having a thickness of 75 μm on one side and a width W4 of 5 mm on the surface is obtained. The exposed portion 3a and the exposed portion 3b of the positive electrode current collector 1 having the same phase as the front surface and a width W5 of 6 mm were formed on the back surface. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 10, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 9.

Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Further, 20 out of 100 lithium ion secondary batteries 17 after 500 cycles of charge / discharge were extracted.
As a result, no defects such as lithium deposition, electrode plate breakage, electrode plate buckling, and electrode mixture layer dropping were observed.

  This is because the exposed portion 3a of the positive electrode current collector 1 having a width W4 is formed on the surface of the positive electrode current collector 1, and the exposed portion 3b of the positive electrode current collector 1 having a width W5 of W5> W4 is formed on the back surface with respect to the longitudinal direction. Due to the uniform formation, when the electrode group 10 is configured, the stress difference due to expansion and contraction due to the difference in curvature between the positive electrode mixture layer 2b on the inner peripheral side and the positive electrode mixture layer 2a on the outer peripheral side. It is considered that good battery characteristics could be maintained.

  In Example 9, the exposed portion 3a of the positive electrode current collector 1 on the front surface and the exposed portion 3b of the positive electrode current collector 1 on the back surface were formed in the same phase. It is also possible to form the exposed portions 3a and 3b of the current collector 1.

  Furthermore, in Example 9, the width W5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate 4 in the electrode group is larger than the width W4 of the exposed portion 3a of the positive electrode current collector 1 on the outer peripheral side. However, the present invention is not limited to this configuration, and the negative electrode current collector 5 is provided with an exposed portion (not shown) so that the exposed portion of the negative electrode current collector 5 on the inner peripheral side of the negative electrode plate 8 is provided. Similarly, it is possible to make the width wider than the width of the exposed portion of the negative electrode current collector on the outer peripheral side.

  As an embodiment of the present invention, the pitch of the exposed portion of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate in the spiral electrode group is narrower than the pitch of the exposed portion of the positive electrode current collector 1 on the outer peripheral side. The embodiment will be described with reference to the drawings.

  First, as shown in FIG. 11, the same positive electrode mixture paint as that of Example 1 was applied to the longitudinal direction of the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm. The exposed portion 3a of the positive electrode current collector 1 having a width of 5 mm on the surface in the vertical direction is formed with a 30 mm pitch P4, and the positive electrode current collector 1 having a width of 5 mm on the back surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 The exposed portion 3b was provided with a 15 mm pitch P5, coated, dried, and then the positive electrode mixture layer 2a, 2b on one side had a thickness of 100 μm.

  Next, the positive electrode plate 4 is pressed to a total thickness of 165 μm, so that the positive electrode current collector 1 having a thickness of 75 μm on one side and a width of 5 mm on the surface is exposed. The portions 3a were formed at a pitch P4 of 30 mm, and the exposed portions 3b of the positive electrode current collector 1 having a width of 5 mm were formed on the back surface at a pitch P5 of 15 mm. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting to a specified width of the cylindrical battery.

  On the other hand, as shown in FIG. 11, the same negative electrode mixture paint as in Example 1 was applied to the negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. After that, the negative electrode plate 8 in which the thickness of the negative electrode mixture layers 6a and 6b on one side was 110 μm was produced. Further, this negative electrode plate 8 was pressed to a total thickness of 180 μm, and then slitted to a specified width of the cylindrical battery to produce the negative electrode plate 8.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound in the E direction through a polyethylene microporous film separator 9 having a thickness of 20 μm were produced.

The electrode group 10 was housed in the bottomed cylindrical battery case 11 together with the insulating plate 12, and the negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Next, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was taken as Example 10.

  Charging / discharging of 100 lithium ion secondary batteries 17 produced as described above was repeated 500 cycles, but cycle deterioration did not occur. Moreover, when 20 pieces were extracted from 100 pieces of 100 lithium ion secondary batteries 17 after repeating 500 cycles of charge and discharge, and the electrode group 10 was disassembled, lithium deposition, electrode plate breakage, electrode plate buckling, electrode No defects such as dropping of the mixture layer were observed.

  This is because the exposed portion 3a of the positive electrode current collector 1 on the surface of the positive electrode current collector 1 has a pitch of P4, and the back surface of the exposed portion 3b of the positive electrode current collector 1 with a pitch P5 of P5 <P4 with respect to the longitudinal direction. When the electrode group 10 is formed, the stress accompanying expansion and contraction due to the difference in curvature between the positive electrode mixture layer 2b on the inner peripheral side and the positive electrode mixture layer 2a on the outer peripheral side when the electrode group 10 is formed. It is considered that the difference could be alleviated and good battery characteristics could be maintained.

  In Example 10, the exposed portion 3a of the positive electrode current collector 1 on the front surface and the exposed portion 3b of the positive electrode current collector 1 on the back surface are formed with the same width, but the width is changed in the longitudinal direction of the front and back surfaces or the same surface. It is possible as well.

  Furthermore, in Example 10, the pitch P5 of the exposed portion 3b of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate 4 in the electrode group is larger than the pitch P4 of the exposed portion 3a of the positive electrode current collector 1 on the outer peripheral side. However, the present invention is not limited to this, and the negative electrode current collector 5 is provided with an exposed portion (not shown) so that the exposed portion of the negative electrode current collector 5 on the inner peripheral side of the negative electrode plate 8 is provided. It is also possible to make the pitch narrower than the pitch of the exposed portion of the negative electrode current collector on the outer peripheral side.

  Further, as another embodiment of the present invention, as shown in Embodiment 1, the thin portion of the positive electrode mixture layer is uniformly provided in the longitudinal direction, or as shown in Embodiment 2. The width of the portion where the thickness of the positive electrode mixture layer is thin is gradually reduced with respect to the winding direction, or the pitch of the portion where the thickness of the positive electrode mixture layer is thin as shown in Example 3 is set in the winding direction. In contrast, the width of the portion where the thickness of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group is small as shown in Example 4 is set on the outer peripheral side. The pitch of the portion where the thickness of the positive electrode mixture layer on the inner peripheral side of the positive electrode plate in the spiral electrode group is thin as shown in Example 5 is wider than the width of the portion where the thickness of the agent layer is thin. Combine any two or more of the positive electrode mixture layers on the outer peripheral side to be narrower than the pitch of the thin part. It is likewise possible to configure Te Align.

  Further, as another embodiment of the present invention, the positive electrode current collector is uniformly provided in the longitudinal direction as shown in the sixth embodiment, or the positive electrode collector is used as shown in the seventh embodiment. The width of the exposed portion of the electric body is reduced stepwise with respect to the winding direction, or the pitch of the exposed portion of the positive electrode current collector is increased stepwise with respect to the winding direction as shown in Example 8. Or, as shown in Example 9, the width of the exposed portion of the positive electrode current collector on the inner peripheral side of the positive electrode plate in the spiral electrode group is larger than the width of the exposed portion of the positive electrode current collector on the outer peripheral side. Or, as shown in Example 10, the pitch of the exposed portion of the positive electrode current collector on the inner peripheral side of the positive electrode plate in the spiral electrode group is set to the pitch of the exposed portion of the positive electrode current collector on the outer peripheral side. Similarly, any two or more of the pitches narrower than the pitch can be combined.

(Comparative Example 1)
First, as shown in FIG. 12, the same positive electrode mixture paint as in Example 1 was applied to the positive electrode current collector 1 made of an aluminum foil (Al purity: 99.85%) having a thickness of 15 μm and dried. The thickness of the positive electrode mixture layers 2a and 2b on one side was set to 75 μm. Then, the positive electrode plate 4 was produced by slitting to a width of 56 mm.

  Next, as shown in FIG. 12, a negative electrode mixture paint similar to that of Example 1 was applied to a negative electrode current collector 5 made of a tough pitch copper foil (Cu purity: 99.9%) having a thickness of 10 μm and dried. Later, the thickness of the negative electrode mixture layers 6a and 6b on one side was set to 85 μm. Then, the negative electrode plate 8 was produced by slitting to a width of 58 mm.

  Using the positive electrode plate 4 and the negative electrode plate 8 produced as described above, a cylindrical lithium ion secondary battery 17 as shown in FIG. 13 was produced. More specifically, 100 electrode groups 10 in which the positive electrode plate 4 and the negative electrode plate 8 were spirally wound through a separator 9 made of a polyethylene microporous film having a thickness of 20 μm were produced.

Ten electrodes were extracted from the electrode group 10 and accommodated in the bottomed cylindrical battery case 11 together with the insulating plate 12. A negative electrode lead 13 led out from the lower part of the electrode group 10 was connected to the bottom of the battery case 11. Subsequently, the positive electrode lead 14 led out from the upper part of the electrode group 10 was connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC were dissolved in a predetermined amount of EC, DMC, and MEC mixed solvent in the battery case 11. A non-aqueous electrolyte solution (not shown) was injected.

  Thereafter, a sealing plate 15 having a sealing gasket 16 attached to the periphery thereof is inserted into the opening of the battery case 11, the opening of the battery case 11 is bent inward, and caulked and sealed. The secondary battery 17 was set as Comparative Example 1.

  As a result of repeating the charge / discharge of 100 lithium ion secondary batteries 17 produced as described above for 500 cycles, cycle deterioration was observed in 4 out of 100 batteries. Thus, when the four lithium ion secondary batteries were disassembled, one was broken by the positive electrode plate 4 and three were crooked by the negative electrode plate 8.

  In the lithium ion secondary battery 17 of the comparative example 1, the degree of expansion and contraction C and D of the positive electrode plate 4 with respect to the degree of expansion and contraction A and B of the negative electrode plate 8 due to expansion and contraction of the negative electrode mixture layers 6a and 6b during charging and discharging. Therefore, it is considered that the positive electrode plate 4 was broken and the negative electrode plate 8 was bent.

  The non-aqueous secondary battery according to the present invention is configured such that the degree of expansion and contraction of the positive electrode plate and the negative electrode plate is close to each other, so The stress applied to the positive electrode plate or the negative electrode plate due to the difference can be relieved, and it is possible to suppress the breakage or buckling of the electrode plate. Since it is possible to provide a secondary battery, it is useful as a portable power source or the like for which higher capacity is desired with the increase in functionality of electronic devices and communication devices.

The fragmentary sectional view which shows the principal part of the electrode group for non-aqueous secondary batteries which shows the principal part of the electrode group after winding in the non-aqueous secondary battery which concerns on one embodiment of this invention The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on one embodiment of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on one Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on the comparative example of this invention. The perspective view which shows the principal part of the electrode group before winding in the non-aqueous secondary battery which concerns on another Example of this invention. 1 is a partially cutaway perspective view of a cylindrical secondary battery according to an embodiment of the present invention. (A) The fragmentary sectional view which shows the principal part of the electrode group for non-aqueous secondary batteries in a prior art example, (b) The principal part of an electrode group when the fracture | rupture of an electrode plate generate | occur | produces in the non-aqueous secondary battery in a prior art example (C) The fragmentary sectional view which shows the principal part of an electrode group in case the buckling of an electrode group generate | occur | produces in the non-aqueous secondary battery in a prior art example Cross-sectional view of a non-aqueous secondary battery in a conventional example Cross-sectional view of a non-aqueous secondary battery in a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode collector 2a, 2b Positive mix layer 3a, 3b Exposed part 3c, 3d Thick place 4 Positive electrode plate 5 Negative electrode collector 6a, 6b Negative mix layer 8 Negative electrode plate 9 Separator 10 Electrode group 11 Battery case 12 Insulating plate 13 Negative electrode lead 14 Positive electrode lead 15 Sealing plate 16 Sealing gasket 17 Lithium ion secondary battery A, B Elasticity of negative electrode plate C, D Elasticity of positive electrode plate E Winding direction P1, P2, P3 of electrode group P4, P5 Pitch W1, W2, W3, W4, W5 where the thickness is thin Width of the portion where the thickness is thin

Claims (13)

  A positive electrode plate having a positive electrode mixture layer formed by adhering a positive electrode mixture coating material obtained by kneading and dispersing an active material comprising at least a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium onto a positive electrode current collector; Between a negative electrode plate in which a negative electrode mixture layer is formed by adhering a negative electrode mixture paint obtained by kneading and dispersing at least an active material made of a material capable of holding lithium and a binder in a dispersion medium onto a negative electrode current collector A non-aqueous secondary battery in which an electrode group formed by winding or laminating a porous insulator is enclosed in a battery case together with a non-aqueous electrolyte solution, the positive electrode mixture layer or the negative electrode mixture The exposed portion of the positive electrode current collector or the negative electrode current collector is provided by partially providing a thin portion on at least one of the layers or by adhering at least one of the positive electrode mixture paint or the negative electrode mixture paint intermittently. By providing the positive electrode plate and Nonaqueous secondary battery, characterized in that to constitute a telescopic degree during charging and discharging of the electrode plate to be close to each other.   The nonaqueous secondary battery according to claim 1, wherein the thin portion of the positive electrode mixture layer or the negative electrode mixture layer is provided uniformly in the longitudinal direction.   The nonaqueous secondary battery according to claim 1, wherein the width of the thin portion of the positive electrode mixture layer or the negative electrode mixture layer is changed stepwise with respect to the winding direction.   The nonaqueous secondary battery according to claim 1, wherein the pitch of the thin portion of the positive electrode mixture layer or the negative electrode mixture layer is changed stepwise with respect to the winding direction.   In the wound electrode group, the width of the thin portion of the positive electrode / negative electrode mixture layer on the outer peripheral side of the positive electrode plate or the negative electrode plate and the width of the thin portion of the positive electrode / negative electrode mixture layer on the inner peripheral side are set. The nonaqueous secondary battery according to claim 1, wherein the nonaqueous secondary battery is changed.   In the wound electrode group, the pitch of the thin portion of the positive electrode / negative electrode mixture layer on the outer peripheral side of the positive electrode plate or the negative electrode plate and the pitch of the thin portion of the positive electrode / negative electrode mixture layer on the inner peripheral side are set. The nonaqueous secondary battery according to claim 1, wherein the nonaqueous secondary battery is changed.   The thin portion of the positive electrode mixture layer or the negative electrode mixture layer is uniformly provided in the longitudinal direction, or the width is changed stepwise with respect to the winding direction, or stepwise with respect to the winding direction. 2. The structure according to claim 1, wherein the pitch is changed, the width is changed between the outer peripheral side and the inner peripheral side, or the pitch is changed between the outer peripheral side and the inner peripheral side. Non-aqueous secondary battery.   The nonaqueous secondary battery according to claim 1, wherein an exposed portion of the positive electrode current collector or the negative electrode current collector is provided uniformly in the longitudinal direction.   The non-aqueous secondary battery according to claim 1, wherein the width of the exposed portion of the positive electrode current collector or the negative electrode current collector is changed stepwise with respect to the winding direction.   The non-aqueous secondary battery according to claim 1, wherein the pitch of the exposed portions of the positive electrode current collector or the negative electrode current collector is changed stepwise with respect to the winding direction.   In the wound electrode group, the width of the exposed portion of the positive / negative current collector on the outer peripheral side of the positive electrode plate or the negative electrode plate and the width of the exposed portion of the positive / negative current collector on the inner peripheral side are changed. The non-aqueous secondary battery according to claim 1. The pitch of the exposed portion of the positive electrode / negative electrode current collector on the outer peripheral side of the positive electrode plate or the negative electrode plate and the pitch of the exposed portion of the positive electrode / negative electrode current collector on the inner peripheral side in the wound electrode group are changed. The non-aqueous secondary battery according to claim 1.   The exposed portion of the positive electrode current collector or the negative electrode current collector is uniformly provided in the longitudinal direction, or the width is changed stepwise with respect to the winding direction, or the pitch is gradually changed with respect to the winding direction. The non-aqueous system according to claim 1, wherein the non-aqueous system is a combination of any two or more of changing, changing the width on the outer peripheral side and the inner peripheral side, or changing the pitch on the outer peripheral side and the inner peripheral side. Secondary battery.

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