JP2011023130A - Nonaqueous secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery of high safety with a structure of an expansion and contraction alleviating function for alleviating expansion and contraction given to a positive electrode plate in the battery, and restraining break or buckling of an electrode plate at charge and discharge through relaxing of stress due to expansion and contraction of the electrode plate at charging and discharging of the battery. <P>SOLUTION: An electrode group 10 structured by winding around a positive electrode plate 4 having positive electrode mixture layers 2a, 2b formed by coating positive electrode mixture paint on a positive electrode collector 1, and an negative electrode plate 8 having negative electrode mixture layers 6a, 6b formed by coating negative electrode mixture paint on an negative electrode collector 5, with an interposition of a separator 9 is so constituted to provide the positive electrode plate 4 with an expansion and contraction alleviating function for alleviating expansion and contraction. <P>COPYRIGHT: (C)2011,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 having the positive electrode mixture layers 22a and 22b formed thereon and the negative electrode plate 26 having the negative electrode mixture layers 25a and 25b formed on the negative electrode current collector 24 through a separator 27 made of a porous insulator. It is conceivable that when the electrode group 28 is formed by winding, and further when the non-aqueous secondary battery is charged and discharged, the electrode plate is broken or buckled by stress applied to the electrode plate. 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 accommodated 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 a non-aqueous secondary battery in which a positive electrode lead 44 is connected to the positive electrode external terminal 46, a 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 prior art 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 electrode plate, it is due to bending stress applied to the positive electrode plate when forming the electrode group. Although the effect of suppressing the breakage of the positive electrode plate is exhibited, the stress due to the expansion and contraction of the electrode plate when charging and discharging the non-aqueous secondary battery can be relieved to suppress the breakage or buckling of the electrode plate during charge and discharge. It had the problem of being difficult.

  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, an electrode group is formed by pressing the electrode plate to a specified thickness and then performing heat treatment and winding to form an electrode group. The electrode plate compressed to the specified thickness by this heat treatment causes buckling. The thickness variation of the 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 has a structure in which a positive and negative electrode plate in a non-aqueous secondary battery is provided with an expansion / contraction relaxation function for relaxing expansion and contraction, and an electrode plate for charging and discharging the non-aqueous secondary battery An object of the present invention is to provide a highly safe non-aqueous secondary battery by relieving the stress accompanying expansion and contraction of the electrode and suppressing fracture 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 An aqueous secondary battery is characterized in that the positive electrode plate is provided with an expansion / contraction relaxation function for relaxing expansion / contraction.

  According to the non-aqueous secondary battery of the present invention, the positive electrode plate is provided with an expansion / contraction relaxation function that relaxes expansion / contraction, resulting in a difference in expansion / contraction between the positive electrode plate and the negative electrode plate during charge / discharge. The stress applied to the positive electrode plate or 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.

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 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. 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

  In the first invention 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 applied onto a positive electrode current collector. A negative electrode mixture layer obtained by applying a negative electrode mixture coating material obtained by kneading and dispersing an active material and a binder made of a material capable of holding lithium at least in a dispersion medium on a negative electrode current collector. A non-aqueous secondary battery in which a porous insulating material is wound or laminated with a non-aqueous electrolyte solution enclosed in a battery case with a porous insulator interposed between the non-aqueous secondary battery and the positive electrode plate By adopting a structure that provides an expansion / contraction relaxation function for relaxing expansion / contraction, the stress applied to the positive electrode plate or the negative electrode plate due to the difference in expansion / contraction due to expansion / contraction between the positive electrode plate and the negative electrode plate during charge / discharge is alleviated. Caused by fracture and electrode plate buckling And it is possible to suppress the internal short circuit, it is possible to provide a highly safe nonaqueous secondary battery.

  In the second invention of the present invention, by forming an exposed portion orthogonal to the longitudinal direction of the positive electrode current collector on at least one surface of the positive electrode mixture layer as a stretching relaxation function, The expansion and contraction function of the positive electrode plate or negative electrode plate can be imparted to the positive electrode plate by optimizing the application conditions of the positive electrode mixture paint without significantly changing the constituent materials. By relieving the stress accompanying this, it becomes possible to suppress breakage or buckling of the electrode plate.

  In the third invention of the present invention, as the expansion / contraction relaxation function, the exposed portion orthogonal to the longitudinal direction of the positive electrode current collector is formed in the same phase on the front and back surfaces of the positive electrode mixture layer. Can effectively disperse the stress associated with the expansion and contraction of the positive electrode plate or the negative electrode plate in the thickness direction of the electrode plate, and more effectively suppress the breakage or buckling of the electrode plate. It becomes.

  In the fourth invention of the present invention, as an expansion / contraction relaxation function, an exposed portion perpendicular to the longitudinal direction of the positive electrode current collector is formed on the front and back surfaces of the positive electrode mixture layer so as to be out of phase. Thus, the effect of relieving the stress accompanying expansion and contraction of the positive electrode plate or the negative electrode plate can be more effectively dispersed in the longitudinal direction of the electrode plate, and the breakage or buckling of the electrode plate can be more effectively suppressed. It becomes possible.

  In the fifth aspect of the present invention, the expansion / contraction relaxation function is formed by changing the width of the exposed portion of the positive electrode current collector, so that the width of the exposed portion is optimized and applied to the positive electrode plate. The stress relaxation effect can be adjusted, and the breakage or buckling of the electrode plate can be suppressed more effectively.

  In the sixth aspect of the present invention, as an example of the expansion / contraction relaxation function, the exposed portion width is changed between the outer peripheral side and the inner peripheral side of the positive electrode mixture layer, thereby forming a positive electrode in a spiral electrode group as an example. By making the width of the thin portion of the positive electrode mixture layer on the inner peripheral side of the plate wider than the width of the thin portion of the positive electrode mixture layer on the outer peripheral side, the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate The resulting stress difference can be mitigated, 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 seventh invention of the present invention, as an expansion / contraction relaxation function, the exposed portion is formed by changing the width of the exposed portion between the winding start side and the winding end side of the positive electrode mixture layer, so that the positive electrode mixture layer is exposed as an example. When the electrode group is configured by gradually widening the width of the part in the winding direction, the stress difference due to the difference in curvature between the start and end of winding of the positive electrode plate can be reduced. It becomes possible to effectively suppress the breakage of the positive electrode plate and the buckling of the electrode plate in the group.

In the eighth invention of the present invention, the outer peripheral side and the inner peripheral side are formed by changing the widths of the outer peripheral side and the inner peripheral side as the expansion / contraction relaxation function and changing the widths of the winding start side and the winding end side. In addition to the effect of changing the width of the exposed portion on the circumferential side, the synergistic effect of changing the width of the exposed portion on the winding start side and the winding end side causes the electrode plate in the electrode group to break and the electrode plate to buckle. Can be more effectively suppressed.

  In the ninth aspect of the present invention, the stress imparted to the positive electrode plate by optimizing the interval between the exposed portions is formed by changing the interval between the exposed portions of the positive electrode current collector as the expansion / contraction relaxation function. The relaxation effect can be adjusted, and the breakage or buckling of the electrode plate can be suppressed more effectively.

  In the tenth aspect of the present invention, as an example of the expansion / contraction relaxation function, the interval between the exposed portions is changed and formed on the outer peripheral side and the inner peripheral side of the positive electrode mixture layer. By making the interval between the exposed portions of the positive electrode mixture layer on the inner peripheral side of the plate narrower than the interval between the exposed portions of the positive electrode mixture layer on the outer peripheral side, the difference in curvature between the outer peripheral side and the inner peripheral side of the positive electrode plate can be obtained. The resulting stress difference can be mitigated, 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 eleventh aspect of the present invention, as an example of the expansion / contraction relaxation function, the exposed portion interval is changed between the winding start side and the winding end side of the positive electrode mixture layer. Since the gap between the portions can be gradually increased with respect to the winding direction, the difference in stress due to the difference in curvature between the start and end of winding of the positive electrode plate can be reduced when the electrode group is configured. It becomes possible to effectively suppress the breakage of the positive electrode plate and the buckling of the electrode plate in the group.

  In the twelfth aspect of the present invention, as the expansion / contraction relaxation function, the exposed portion is formed by changing the interval between the outer peripheral side and the inner peripheral side and changing the interval between the winding start side and the winding end side. In addition to the effect of changing the interval between the exposed portions on the side, the synergistic effect of changing the interval between the exposed portions on the winding start side and the winding end side reduces the breakage of the electrode plate and the electrode plate in the electrode group. It becomes possible to suppress effectively.

  In the thirteenth aspect of the present invention, the width of the exposed portion of the positive electrode current collector is changed as an expansion / contraction relaxation function, and the exposed portion is formed by changing the interval between the exposed portions of the positive electrode current collector. In addition to the effect of changing the width, it is possible to effectively suppress the breakage of the electrode plate and the buckling of the electrode plate in the electrode group by the synergistic effect of changing the interval between the exposed portions.

  In the fourteenth aspect of the present invention, by providing an expansion / contraction relaxation function and an expansion / contraction promotion function for promoting expansion / contraction in the positive electrode plate, a difference in expansion / contraction due to expansion / contraction of the positive electrode plate and the negative electrode plate during charging / discharging. By relieving the stress applied to the positive electrode plate or the negative electrode plate due to the above and increasing the degree of expansion / contraction of the other electrode plate, the degree of expansion / contraction between the positive electrode plate and the negative electrode plate can be made more effective.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of an electrode group 10 after winding in a nonaqueous 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. In the negative electrode plate 8 in which the agent coating material is applied on the negative electrode current collector 5 to form the negative electrode mixture layers 6a and 6b, the positive electrode plate 4 is provided with an expansion / contraction relaxation function, and the positive electrode plate 4 and the negative electrode A separator 9 as a porous insulator is interposed between the plate 8 and the plate 8 so as to be spirally wound.

Here, in the lithium ion secondary battery represented by the non-aqueous secondary battery of the present invention described above, the negative electrode mixture is obtained by intercalating lithium with the negative electrode plate 8 during charging as shown in FIG. Stress applied to the negative electrode plate 8 or the positive electrode plate 4 due to the difference in elongation between the degree of elongation A of the negative electrode plate 8 due to expansion of the layers 6a and 6b and the degree of elongation C of the positive electrode plate 4 at this time, and the negative electrode during discharge Due to the difference in contraction between the contraction degree B of the negative electrode plate 8 and the contraction degree D of the positive electrode plate 4 due to the contraction of the negative electrode mixture layers 6a and 6b due to deintercalation of lithium from the plate 8. In order to relieve the stress applied to the negative electrode plate 8 or the positive electrode plate 4 generated, the positive electrode plate 4 is provided with an expansion / contraction relaxation function for relaxing expansion / contraction. 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 prepared as described above is applied on the positive electrode current collector 1 made of, for example, an aluminum foil using a die coater, dried and pressed to a predetermined thickness. A long belt-like positive electrode plate 4 is obtained by slitting into a width and a length.

  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, A long strip-shaped negative electrode plate 8 is obtained by slitting into a width and a length.

  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 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 is 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. 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. In order to form a good film on the positive electrode plate 4 or the negative electrode plate 8 and to ensure stability during overcharge, vinylene carbonate (VC), cyclohexylbenzene (CHB), and modified products thereof are used. It is preferable to use it.

  As a first configuration of the expansion / contraction relaxation function that is a feature of the present invention, the electrode plate for a non-aqueous secondary battery of the present invention is orthogonal to the longitudinal direction of the positive electrode mixture layers 2a and 2b as shown in FIG. This can be realized by forming the exposed portion so as to have the same phase. As an example of a specific structure, the exposed portion 3a of the positive electrode mixture layer 2a is equidistantly provided on the surface of the positive electrode current collector 1 shown in FIG. An exposed portion 3b of the layer 2b is formed.

  First, in order to form the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b, the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b are elongated in the longitudinal direction of the positive electrode current collector 1 shown in FIG. It is manufactured through a first process in which the exposed portion 3a and the exposed portion 3b are applied and formed at equal intervals in the direction and in the same phase. Next, after the positive electrode mixture coating material is dried, the exposed portion 3a, 3b of the positive electrode mixture layers 2a, 2b on the positive electrode plate 4 in the longitudinal direction and the like is pressed to a predetermined thickness. Formed at intervals. The exposed surface 3a, 3b of the positive electrode mixture layer 2a, 2b formed in the same phase in the front surface and the back surface and at equal intervals in the longitudinal direction has an effect of relaxing expansion / contraction of the positive electrode plate 4 or the negative electrode plate 8 By doing so, the stress applied to the positive electrode plate 4 or the negative electrode plate 8 can be relaxed, and 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, as a second configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery of the present invention has an exposed portion 3a, which is orthogonal to the longitudinal direction of the positive electrode mixture layers 2a, 2b as shown in FIG. This can be realized by forming and configuring 3b to have different phases. As an example of a specific configuration, the exposed portion 3a of the positive electrode mixture layer 2a is equidistantly formed on the surface of the positive electrode current collector 1 shown in FIG. An exposed portion 3b of 2b is formed.

First, in order to form the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b, the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b are elongated in the longitudinal direction of the positive electrode current collector 1 shown in FIG. It is manufactured through a first step of coating and forming at equal intervals with respect to the direction and so that the phase of the exposed portion 3a and the exposed portion 3b is shifted by 1/2. Next, after the positive electrode mixture coating material is dried, the positive electrode plate is subjected to 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 of the exposed portions 3a and 3b. 4, exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b are formed at equal intervals in the longitudinal direction. An effect of relaxing the expansion and contraction of the positive electrode plate 4 or the negative electrode plate 8 on the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b formed on the front surface and the rear surface in different phases and at equal intervals in the longitudinal direction. By applying, the stress applied to the positive electrode plate 4 or the negative electrode plate 8 can be relaxed, and the expansion degrees C and D of the positive electrode plate 4 and the expansion degrees A and B of the negative electrode plate 8 can be brought close to each other. As a third configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery according to the present invention has a width of the exposed portions 3a and 3b and the outer peripheral side of the positive electrode mixture layers 2a and 2b as shown in FIG. This can be realized by forming and changing the inner peripheral side. As an example of a specific configuration, as shown in FIG. 4, the exposed portion 3a of the positive electrode mixture layer 2a having the width W2 is formed on the surface of the positive electrode current collector 1, and the positive electrode mixture having the width W3 satisfying W3> W2 on the back surface. The exposed portion 3b of the layer 2b is uniformly formed in the longitudinal direction. With this configuration, when the electrode group 10 is formed by spirally winding in the E direction, 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 Compressive stress is applied to the negative electrode mixture layer 6b, but the width of the exposed portion 3b 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. By forming W3 wider than the width W2 of the exposed portion 3a of the positive electrode mixture layer 2a on the outer peripheral side, expansion and contraction of the negative electrode plate 8 are more effectively suppressed, and stress applied to the positive electrode plate 4 is relieved. Become.

  In order to form the above-described exposed portions 3a and 3b in a part of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, a positive electrode mixture layer having a width W2 on the surface of the positive electrode current collector 1 as shown in FIG. The exposed portion 3a of 2a and the exposed portion 3b of the positive electrode mixture layer 2b having a width W3 satisfying W3> W2 are formed on the back surface through a first process in which the exposed portion 3b is uniformly applied in the longitudinal direction. Next, the width W3 of the exposed portion 3b of the positive electrode mixture layer 2b on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is passed through a second step in which the positive electrode mixture paint is dried and pressed to a predetermined thickness. The exposed portions 3a and 3b are uniformly formed in the longitudinal direction so that the width W2 of the exposed portion 3a of the positive electrode mixture layer 2a on the outer peripheral side is wider. Further, as a fourth configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery according to the present invention has a width of the exposed portions 3a and 3b as shown in FIG. 5 and the winding start side of the positive electrode mixture layers 2a and 2b. It can be realized by forming and changing at the winding end side. As an example of a specific configuration, as shown in FIG. 5, an exposed portion 3a having widths W4> W5> W6 in order from the beginning of winding on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1 is formed on the back surface. An exposed portion 3b having widths W4> W5> W6 is formed stepwise in the winding direction in order from the beginning of winding in the same phase as the surface. With this configuration, when the electrode group 10 shown in FIG. 13 is formed by spirally winding in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding more than the negative electrode plate 8 at the end of winding due to the difference in curvature. However, the negative electrode plate 8 in the electrode group 10 is formed by forming the exposed portions 3a and 3b wider than the positive electrode plate 4 at the end of rolling on the positive electrode plate 4 at the start of winding opposite to the negative electrode plate 8 at the start of winding. Therefore, the stress applied to the positive electrode plate 4 is alleviated more effectively.

  In order to form the exposed portions 3a and 3b in the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the positive electrode mixture is formed on the front and rear surfaces perpendicular to the longitudinal direction of the positive electrode current collector 1 as shown in FIG. The exposed portions 3a and 3b of the agent layers 2a and 2b are manufactured through a first process in which the widths W4> W5> W6 are sequentially applied in the winding direction in order from the start of winding. Then, after the positive electrode mixture coating material is dried and then pressed to a predetermined thickness, the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b are wound in the winding direction in the longitudinal direction of the positive electrode plate 4. Are formed in stages. Further, as a fifth configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery of the present invention changes the width of the outer peripheral side and the inner peripheral side of the positive electrode mixture layers 2a and 2b as shown in FIG. Similarly, it is possible to make the expansion degree of the positive electrode plate 4 and the expansion degree of the negative electrode plate 8 close to each other by forming the exposed portions 3a and 3b by changing the width of the winding start side and the winding end side. . As an example of a specific configuration, as shown in FIG. 6, an exposed portion 3a having widths W4> W5> W6 in order from the beginning of winding on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1 is formed on the back surface. An exposed portion 3b having a width W7> W8> W9 (W7> W4 here) is formed stepwise in the winding direction in order from the beginning of winding.

  Further, as a sixth configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery according to the present invention has an interval between the exposed portions 3a and 3b and the outer peripheral side of the positive electrode mixture layers 2a and 2b as shown in FIG. This can be realized by forming and changing the inner peripheral side. As an example of a specific configuration, as shown in FIG. 7, the exposed portion 3a of the positive electrode mixture layer 2a is formed on the surface of the positive electrode current collector 1 at an interval P1, and the back surface is formed at an interval P2 where P2 <P1. An exposed portion 3b of the agent layer 2b is formed. With this configuration, when the electrode group 10 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 compressive stress is applied to the agent layer 6b, the interval P2 between the exposed portions 3b 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 set to the outer periphery. By forming narrower than the interval P2 of the exposed portion 3a of the positive electrode mixture layer 2a on the side, the expansion and contraction of the negative electrode plate 8 is more effectively suppressed, and the stress applied to the positive electrode plate 4 is relieved.

  In order to form the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the exposed portion 3a of the positive electrode mixture layer 2a is formed on the surface of the positive electrode current collector 1 as shown in FIG. It is manufactured through a first step in which the exposed portion 3b of the positive electrode mixture layer 2b is applied and formed on the back surface at a distance P2 where P2 <P1. Next, after the positive electrode mixture coating material is dried and then pressed to a predetermined thickness, the interval P2 between the exposed portions 3b of the positive electrode mixture layer 2b on the inner peripheral side in the longitudinal direction of the positive electrode plate 4 is obtained. The exposed portions 3a and 3b are formed so as to be narrower than the interval P1 between the exposed portions 3a of the positive electrode mixture layer 2a on the outer peripheral side. Further, as a seventh configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery according to the present invention has an interval between the exposed portions as shown in FIG. 8 with the winding start side and the winding end of the positive electrode mixture layers 2a and 2b. It can be realized by forming and configuring on the side. As an example of a specific configuration, as shown in FIG. 8, the surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 has a spacing P3 <P4 <in order from the beginning of winding the exposed portion 3a around the positive electrode mixture layer 2a. The back surface is formed stepwise with respect to the winding direction at intervals of P3 <P4 <P5 in order from the start of winding the exposed portion 3b in phase with the surface around a part of the positive electrode mixture layer 2b at intervals of P5. Yes. With this configuration, when the electrode group 10 shown in FIG. 13 is formed by spirally winding in the E direction, bending stress is applied to the negative electrode plate 8 at the beginning of winding more than the negative electrode plate 8 at the end of winding due to the difference in curvature. The negative electrode plate 8 in the electrode group 10 is formed by forming the exposed portions 3a and 3b at a narrower interval than the positive electrode plate 4 at the end of rolling on the positive electrode plate 4 at the start of winding opposite to the negative electrode plate 8 at the start of winding. Therefore, the stress applied to the positive electrode plate 4 is alleviated more effectively.

  In order to form the exposed portions 3a and 3b in the positive electrode mixture layers 2a and 2b in the positive electrode plate 4, the exposed portions of the positive electrode mixture layers 2a and 2b in the longitudinal direction of the positive electrode current collector 1 as shown in FIG. 3a and 3b are manufactured through a first process in which the winding is sequentially applied in the winding direction at intervals of P3 <P4 <P5 from the start of winding. Then, after the positive electrode mixture paint is dried, the exposed portions 3a and 3b of the positive electrode mixture layers 2a and 2b are wound in the winding direction in the longitudinal direction of the positive electrode plate 4 through a second step of pressing to a predetermined thickness. Are formed in stages. As an eighth configuration of the expansion / contraction relaxation function, the electrode plate for a non-aqueous secondary battery according to the present invention changes the interval between the outer peripheral side and the inner peripheral side of the positive electrode mixture layers 2a and 2b as shown in FIG. Similarly, it is possible to make the expansion degree of the positive electrode plate 4 and the expansion degree of the negative electrode plate 8 close to each other by forming the exposed portion by changing the interval between the winding start side and the winding end side. As an example of a specific configuration, as shown in FIG. 9, the surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 has an interval P3 <P4 <in order from the beginning of winding the exposed portion 3a around the positive electrode mixture layer 2a. The back surface is formed stepwise in the winding direction at intervals of P6 <P7 <P8 (where P6> P3) in order from the start of winding the exposed portion 3b around the positive electrode mixture layer 2b at intervals of P5. Yes.

  As a ninth configuration of the expansion / contraction suppression function, the electrode plate for a non-aqueous secondary battery of the present invention changes the width of the exposed portions 3a and 3b of the positive electrode current collector 1 as shown in FIG. This can be realized by changing the interval between the exposed portions 3a and 3b of the electric body 1 to form the exposed portions 3a and 3b. As an example of a specific configuration, as shown in FIG. 10, the width is W4> W5> W6 in order from the beginning of winding on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and the interval is P1 < The exposed portion 3a where P2 <P3 is wound on the back surface in the same phase as the front surface, and the exposed portion 3b where the width is W4> W5> W6 and the interval is P1 <P2 <P3 with respect to the winding direction. It is formed step by step. Furthermore, as a structure combining the expansion / contraction relaxation function and the expansion / contraction promotion function, the electrode plate for a non-aqueous secondary battery according to the present invention provides the expansion / contraction relaxation function for the positive electrode plate 4 as shown in FIG. This can be realized by providing an expansion / contraction accelerating function for accelerating expansion / contraction in the direction where the degree of expansion / contraction during charging / discharging of the plate 8 is small. As an example of a specific configuration, as shown in FIG. 11, the exposed portion 3 a of the positive electrode mixture layer 2 a is equidistantly formed on the surface of the positive electrode current collector 1, and the positive electrode is equidistantly spaced on the back surface in phase with the surface. While forming the exposed part 3b of the mixture layer 2b, the positive electrode current collector 1 is provided with a thin part 1a orthogonal to the longitudinal direction.

  Next, nonaqueous secondary batteries according to embodiments of the present invention will be described in detail with reference to the drawings.

  As an embodiment of the present invention, an embodiment in which exposed portions orthogonal to the longitudinal direction of the positive electrode current collector are provided in the same phase on the front and back surfaces of the positive electrode mixture layer will be described 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. The exposed portions 3a having a width of 5 mm are arranged at an equal pitch, and the exposed portions 3b having the same phase as the front surface and a width of 5 mm on the back surface perpendicular to the longitudinal direction of the positive electrode current collector 1 are arranged at an equal pitch with respect to the longitudinal 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 intermittent application, drying, and drying was prepared. Further, by pressing the positive electrode plate 4 so that the total thickness becomes 165 μm, the exposed portion 3 a having a thickness of 75 μm on one side of the positive electrode mixture layers 2 a and 2 b and a width of 5 mm on the surface An exposed portion 3b having the same phase as the front surface and a width of 5 mm was formed uniformly on the back surface in the longitudinal direction. Then, the positive electrode plate 4 was produced by slitting into a prescribed 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, it 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 pressed to have an active material density of 1.6 g. / Cc, and 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 into a prescribed 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. Next, the positive electrode lead 14 led out from the upper part of the electrode group 10 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 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 can be relaxed, and the degree of expansion and contraction of the positive electrode plate 4 can be brought close to the degree of expansion and contraction of the negative electrode plate 8, thereby maintaining good battery performance. In Example 1, 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 with the same width, but the exposed portions 3a and 3b on the front and back surfaces of the positive electrode plate 4 were formed. It is also possible to form the exposed portions 3 a and 3 b of the positive electrode current collector 1 by changing the width of the positive electrode current collector 1.

  As another example of the present invention, an example in which exposed portions orthogonal to the longitudinal direction of the positive electrode current collector are provided in different phases on the front and back surfaces of the positive electrode mixture layer while referring to the drawings. explain. First, as shown in FIG. 3, a positive electrode mixture paint similar to that in Example 1 was 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. The exposed portions 3a having a width of 5 mm are equidistantly formed on the surface of the positive electrode current collector 1 and the exposed portions 3b having a width of 5 mm having a phase shifted by 1/2 from the front surface on the back surface perpendicular to the longitudinal direction of the positive electrode current collector 1 After coating, drying, and drying at intervals, the thickness of the positive electrode mixture layers 2a, 2b on one side is 100 μm, and the exposed portions 3a, 3b of the positive electrode mixture layers 2a, 2b A positive electrode plate 4 having a thickness of 65 μm was prepared. 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 a width of 5 mm and a thickness of 65 μm. The exposed portion 3a of the agent layer 2a and the exposed portion 3b of the positive electrode mixture layer 2b having a width of 5 mm and a thickness of 65 μm, which are ½ phase shifted from the front surface, were uniformly formed in the longitudinal direction on the back surface. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

  On the other hand, as shown in FIG. 3, 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 exposed portion 3a of the positive electrode mixture layer 2a on the surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1, the exposed portion of the positive electrode mixture layer 2b having the same width as the front surface and a different phase on the back surface. By forming 3b in the longitudinal direction, expansion of the negative electrode plate 8 when lithium was intercalated and volume change due to contraction of the negative electrode plate 8 when lithium was deintercalated could be mitigated. In addition, it is considered that good battery performance was maintained. In Example 2, 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 with the same width, but the exposed portions 3a and 3b on the front and back surfaces of the positive electrode plate 4 were formed. It is also possible to form the exposed portions 3 a and 3 b of the positive electrode current collector 1 by changing the width of the positive electrode current collector 1.

As another 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 wider than the width of the exposed portion of the positive electrode current collector on the outer peripheral side. The embodiment 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. The exposed portions 3a of the positive electrode current collector 1 having a width W2 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 W3 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 as to have a total thickness of 165 μm, whereby the positive electrode current collector 1 having a positive electrode mixture layer 2a, 2b on one side having a thickness of 75 μm and a width W2 of 5 mm on the surface. The exposed portion 3a of the positive electrode current collector 1 having the same phase as the front surface and a width W3 of 6 mm was formed on the back surface. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

  On the other hand, as shown in FIG. 4, the 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 exposed portion 3a of the positive electrode current collector 1 having a width W2 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 W3 satisfying W3> W2 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 performance was maintained. In Example 3, 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.

As another embodiment of the present invention, an embodiment in which the width of the exposed portion 3a of the positive electrode current collector 1 is reduced stepwise with respect to the winding direction 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. 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 start of winding on the surface in the vertical direction are arranged at equal pitches, 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 start of winding 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 stepwise in the winding direction at a pitch, applied and dried.

  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, 2b on one side is 75 μm and the surface has W4 = 5 mm> W5 = 4.5 mm>. The exposed portion 3a of the positive electrode current collector 1 with W6 = 4.0 mm and the exposed portion 3b of the positive electrode current collector 1 with W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm in the same phase as the front surface on the back surface. Was formed stepwise with respect to the winding direction. Then, the positive electrode plate 4 was produced by slitting into a prescribed 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 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 the exposed portion 3a of the positive electrode current collector 1 whose width is narrowed sequentially from the beginning in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 is wound at an equal pitch and on the back surface at 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 from the positive electrode mixture layers 2a and 2b at the end can be alleviated, and good battery performance can be maintained. In Example 4, 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. It is also possible to form the exposed portions 3a and 3b of the current collector 1.

As another 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 wider than the width of the exposed portion of the positive electrode current collector on the outer peripheral side. In addition, 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. 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 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 start of winding on the surface in the vertical direction are arranged at equal pitches, and the positive electrode current collector 1 W7 = 6 mm> W8 = 5.5 mm> W9 = 5. From the beginning of winding on the back surface perpendicular to the longitudinal direction.
The thickness of the positive electrode mixture layers 2a and 2b on one side is set after the exposed portions 3b of the positive electrode current collector 1 having a width of 0 mm and the width of the positive electrode current collector 1 are successively applied at an equal pitch in the winding direction and dried. A positive electrode plate 4 having a thickness of 100 μm was produced. 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, 2b on one side is 75 μm and the surface has W4 = 5 mm> W5 = 4.5 mm>. The exposed portion 3a of the positive electrode current collector 1 with W6 = 4.0 mm and the exposed portion 3b of the positive electrode current collector 1 with W7 = 6 mm> W8 = 5.5 mm> W9 = 5.0 mm in the winding direction on the back surface. In contrast, it was formed stepwise. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

  On the other hand, as shown in FIG. 6, the 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 the width of the exposed portion 3b on the back surface of the positive electrode current collector 1 is formed wider than the width of the exposed portion 3a on the front surface, so that the positive electrode mixture layer 2b on the inner peripheral side when the electrode group 10 is formed. It is considered that the stress difference accompanying expansion and contraction due to the difference in curvature between the positive electrode mixture layer 2a on the outer peripheral side and the positive electrode mixture layer 2a could be relaxed. In addition to this, the exposed portion 3a whose width is sequentially narrowed in the order of W4> W5> W6 from the beginning of winding on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and W7> W8> from the beginning of winding on the back surface. By forming W9 and the exposed portion 3b whose width is sequentially narrowed in a stepwise manner in the winding direction, the positive electrode mixture layers 2a and 2b at the beginning of winding and the positive electrode mixture layers 2a and 2b at the end of winding in the electrode group 10 are formed. It is considered that the stress difference due to expansion and contraction due to the difference in curvature with respect to the above could be alleviated, and good battery characteristic battery performance could be maintained.

As another embodiment of the present invention, the interval between the exposed portions of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate in the spiral electrode group is larger than the interval between the exposed portions of the positive electrode current collector on the outer peripheral side. A narrowed embodiment 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. 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 spaced by a distance P1 of 30 mm, and the positive electrode current collector 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 After the 1 exposed portion 3b was applied with a spacing P2 of 15 mm, and coated and dried, 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. Next, the positive electrode plate 4 is pressed so that the total thickness becomes 165 μm, so that the positive electrode mixture layer 2a on one side is pressed.
, 2b has a thickness of 75 μm, the exposed portion 3a of the positive electrode current collector 1 having a width of 5 mm on the surface is spaced by a distance P1, and the exposed portion 3b of the positive electrode current collector 1 having a width of 5 mm is 15 mm on the back surface. Formed at the interval P2. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

On the other hand, as shown in FIG. 7, the 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 portion 3a of the positive electrode current collector 1 is placed on the surface of the positive electrode current collector 1 at an interval P1, and the back surface is exposed at an interval P2 where P2 <P1. 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 performance could be maintained. In Example 6, 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.

  As another embodiment of the present invention, an embodiment in which the interval between the exposed portions 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. 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%). From the beginning of winding the exposed portion 3a of the positive electrode current collector 1 having a width of 5 mm on the surface in the vertical direction, the pitch P3 = 20 mm <P4 = 30 mm <P5 = 40 mm 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 from the start of winding, and is provided at intervals of P3 = 20 mm <P4 = 30 mm <P5 = 40 mm. 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 so that the total thickness is 165 μm, so that the positive electrode mixture layers 2 a and 2 b on one side have a thickness of 75 μm and the surface has a width of 5 mm. The exposed portion 3a is spaced at an interval of P3 = 20 mm <P4 = 30 mm <P5 = 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 is exposed to P3 = 20 mm <P4 = 30 mm <P5. = It formed in steps with respect to the winding direction at intervals of 40 mm. Then, the positive electrode plate 4 was produced by slitting into a prescribed 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 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 interval is gradually increased from the beginning of winding 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 from the start of winding so that the interval is gradually increased and stepwise formed in the winding direction. It is considered that the stress difference due to expansion and contraction caused by 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 performance can be maintained. It is done. In Example 7, 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.

  As another embodiment of the present invention, the interval between the exposed portions of the positive electrode current collector 1 on the inner peripheral side of the positive electrode plate in the spiral electrode group is larger than the interval between the exposed portions of the positive electrode current collector 1 on the outer peripheral side. An example in which the distance between the exposed portions 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. The exposed portion 3a of the positive electrode current collector 1 having a width of 5 mm is wound on the surface in the vertical direction at intervals of P3 = 20 mm <P4 = 30 mm <P5 = 40 mm 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 a width of 5 mm is provided on the back surface in the direction from the start of winding at an interval of P6 = 15 mm <P7 = 25 mm <P8 = 35 mm, and is applied stepwise in the winding direction and dried. Then, a positive electrode plate 4 was produced in which the thickness of the positive electrode mixture layers 2a and 2b on one side was 100 μm.

Next, the positive electrode plate 4 is pressed so that the total thickness is 165 μm, so that the positive electrode mixture layers 2 a and 2 b on one side have a thickness of 75 μm and the surface has a width of 5 mm. The exposed portions 3a are spaced at intervals of P3 = 20 mm <P4 = 30 mm <P5 = 40 mm, and the exposed portions 3b of the positive electrode current collector 1 having a width of 5 mm on the back surface are spaced at intervals of P6 = 15 mm <P7 = 25 mm <P8 = 35 mm. It formed in steps with respect to the winding direction. Then, the positive electrode plate 4 was produced by slitting into a prescribed 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 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 gap between the exposed portions 3b on the back surface of the positive electrode current collector 1 is narrower than the interval between the exposed portions 3a on the front surface, so that the positive electrode mixture layer 2b on the inner peripheral side when the electrode group 10 is formed. It is considered that the stress difference accompanying expansion and contraction due to the difference in curvature between the positive electrode mixture layer 2a on the outer peripheral side and the positive electrode mixture layer 2a could be relaxed. In addition to this, the exposed portion 3a, which is gradually spaced from P3 <P4 <P5 from the beginning of winding on the surface perpendicular to the longitudinal direction of the positive electrode current collector 1, and P6 <P7 < P8 and the exposed portion 3b whose width is sequentially narrowed are formed stepwise in the winding direction, so that the positive electrode mixture layers 2a and 2b at the beginning of winding and the positive electrode mixture layers 2a and 2b at the end of winding in the electrode group 10 are formed. It is considered that the stress difference due to expansion and contraction due to the difference in curvature with respect to the above could be alleviated, and good battery characteristic battery performance could be maintained.

  As another embodiment of the present invention, the width of the exposed portion of the positive electrode current collector is reduced stepwise with respect to the winding direction, and the interval between the exposed portions of the positive electrode current collector is stepped with respect to the winding direction. Embodiments that are broadened will be described with reference to the drawings. First, as shown in FIG. 10, the positive electrode mixture paint similar to that of Example 1 was 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. W1 = 20 mm <P2 = 30 mm <P3 = from the beginning of winding the exposed portion 3a of the positive electrode current collector 1 whose width is sequentially narrowed to W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm from the beginning of winding W4 = 5 mm> W5 = 4.5 mm> W6 = 4.0 mm from the beginning of winding on the back surface perpendicular to the longitudinal direction of the positive electrode current collector 1 in the same phase as the front surface at intervals of 40 mm, and the width becomes narrower sequentially. After the exposed portion 3b of the positive electrode current collector 1 is wound, it is applied stepwise in the winding direction at intervals of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm, and is applied and dried, and then the positive electrode assembly on one side is combined. The thickness of the agent layers 2a and 2b is 100 μm And the positive electrode plate 4 from which the thickness of the exposed parts 3a and 3b of positive mix layer 2a and 2b was set to 75 micrometers was produced.

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, 2b on one side is 75 μm and the surface has W4 = 5 mm> W5 = 4.5 mm>. The exposed portion 3a of the positive electrode current collector 1 with W6 = 4.0 mm is spaced at an interval of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm, and in the same phase as the front surface at the back surface W4 = 5 mm> W5 = 4.5 mm>
The exposed portion 3b of the positive electrode current collector 1 with W6 = 4.0 mm was formed stepwise in the winding direction at intervals of P1 = 20 mm <P2 = 30 mm <P3 = 40 mm. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

  On the other hand, as shown in FIG. 10, the negative electrode mixture paint similar to that of 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. 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 into a prescribed 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 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 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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. 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 in addition to the effect of alleviating the stress difference accompanying expansion and contraction caused by the difference in curvature between the winding start and the winding end in the electrode group 10 by changing the width of the exposed portions 3a and 3b of the positive electrode current collector 1. Expansion and contraction by a synergistic effect of alleviating the stress difference associated with expansion and contraction caused by the difference in curvature between the winding start and the winding end in the electrode group 10 by changing the interval between the exposed portions 3a and 3b of the positive electrode current collector 1 It can be considered that the stress difference accompanying the process can be more effectively mitigated and good battery performance can be maintained.

  As another example of the present invention, an exposed portion perpendicular to the longitudinal direction of the positive electrode current collector is provided in the same phase on the front and back surfaces of the positive electrode mixture layer, and the positive electrode current collector is disposed in the longitudinal direction. An embodiment configured by providing orthogonal thin portions will be described with reference to the drawings. First, as shown in FIG. 11, a positive electrode mixture paint similar to that in Example 1 was provided with thin portions 1a having a depth of 2 μm at equal intervals in the direction perpendicular to the longitudinal direction, and an aluminum foil having a thickness of 15 μm (Al The exposed portions 3a having a width of 5 mm are formed on the surface in the direction perpendicular to the longitudinal direction of the positive electrode current collector 1 having a purity of 99.85%) at an equal pitch and perpendicular to the longitudinal direction of the positive electrode current collector 1 The thickness of the positive electrode mixture layers 2a, 2b on one side after the exposed portions 3b having the same phase as the front surface and 5 mm wide on the back surface in the direction are uniformly applied to the longitudinal direction at equal pitches and dried. A positive electrode plate 4 having a thickness of 100 μm was produced. Next, this positive electrode plate 4 is pressed so that the total thickness becomes 165 μm, so that the thickness of the positive electrode mixture layers 2 a and 2 b on one side is 75 μm, and the exposed portion 3 a having a width of 5 mm is formed on the surface. An exposed portion 3b having the same phase as the front surface and a width of 5 mm was formed uniformly on the back surface in the longitudinal direction. Then, the positive electrode plate 4 was produced by slitting into a prescribed width of the cylindrical battery.

On the other hand, as shown in FIG. 11, the 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. 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 into a prescribed 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 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.

Next, the positive electrode lead 14 led out from the upper part of the electrode group 10 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 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 could be relaxed. In addition to this, by providing the thin-walled portion 1a on the positive electrode current collector 1, the positive electrode plate 4 can be easily stretched, and the expansion and contraction degrees of the positive electrode plate 4 and the negative electrode plate 8 can be made closer to each other. It is thought that it was able to maintain. In the lithium ion secondary battery 17 having the configuration in Example 10, the positive electrode plate 4 has a smaller degree of expansion / contraction during charge / discharge than the negative electrode plate 8, so that the expansion / contraction promotion function promotes expansion / contraction of the positive electrode plate 4. Although the thin part 1a orthogonal to the longitudinal direction was provided in the positive electrode current collector 1, the present invention is not limited to this, and the negative electrode plate 8 is different from that in Example 10 in charge and discharge. For the lithium ion secondary battery 17 having a low degree of expansion / contraction, it is also possible to provide the negative electrode plate 8 with an expansion / contraction promotion function for promoting expansion / contraction.

(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 into a prescribed width of the cylindrical battery.

On the other hand, as shown in FIG. 12, 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 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 into a prescribed 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. 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. Next, the positive electrode lead 14 led out from the upper part of the electrode group 10 is connected to the sealing plate 15, and 1 part of LiPF ₆ and 3 parts by weight of VC are 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 17 were disassembled, one was broken by the positive electrode plate 4 and three were bent by the negative electrode plate 8. In the lithium ion secondary battery 17 of Comparative Example 1 described above, the degree of expansion C of the positive electrode plate 4 with respect to the degree of expansion 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. Since D could not follow, it is considered that the positive electrode plate 4 was broken and the negative electrode plate 8 was buckled.

  According to the present invention, the positive electrode plate or the negative electrode plate caused by the difference in expansion and contraction due to the expansion and contraction of the positive electrode plate and the negative electrode plate during charging / discharging is provided by providing the positive electrode plate with an expansion / contraction relaxation function for relaxing expansion / contraction. It is possible to relieve the stress applied to the electrode, and it is possible to suppress breakage or buckling of the electrode plate, and it is possible to provide a highly safe non-aqueous secondary battery by suppressing internal short circuit caused by these Therefore, it is useful as a portable power source or the like for which a higher capacity is desired along with the multifunctionalization of electronic devices and communication devices.

DESCRIPTION OF SYMBOLS 1 Positive electrode collector 1a Thin part 2a, 2b Positive electrode mixture layer 3a, 3b Exposed part 4 Positive electrode plate 5 Negative electrode collector 6a, 6b Negative electrode mixture 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 Stretching degree of negative electrode plate C, D Stretching degree of positive electrode plate E Winding direction of electrode group P1, P2, P3, P4, P5 P6, P7, P8 Exposed portion spacing W2, W3, W4, W5, W6, W7, W8, W9 Exposed portion width

Claims (14)

  A positive electrode plate having a positive electrode mixture layer formed by applying 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 on a positive electrode current collector; A negative electrode mixture coating material in which an active material made of a material capable of holding lithium and a binder are kneaded and dispersed in a dispersion medium is applied on the negative electrode current collector to form a porous material between the negative electrode plate and the negative electrode plate. A non-aqueous secondary battery in which an electrode group formed by winding or stacking in a spiral shape with a porous insulator interposed is enclosed in a battery case together with a non-aqueous electrolyte solution, and the expansion and contraction of the positive electrode plate is reduced. A non-aqueous secondary battery characterized by having a structure provided with an expansion / contraction relaxation function.   The non-aqueous secondary battery according to claim 1, wherein an exposed portion orthogonal to the longitudinal direction of the positive electrode current collector is formed on at least one surface of the positive electrode mixture layer as the expansion / contraction relaxation function.   3. The exposed portion perpendicular to the longitudinal direction of the positive electrode current collector is formed on the front surface and the back surface of the positive electrode mixture layer so as to have the same phase as the elongation relaxation control function. The nonaqueous secondary battery as described.   3. The expansion and contraction relaxation function is formed by forming exposed portions orthogonal to the longitudinal direction of the positive electrode current collector on the front and back surfaces of the positive electrode mixture layer so as to have different phases. The nonaqueous secondary battery as described.   The non-aqueous secondary battery according to claim 2, wherein the expansion / contraction relaxation function is formed by changing a width of an exposed portion of the positive electrode current collector.   6. The non-aqueous secondary battery according to claim 5, wherein, as the expansion / contraction relaxation function, the width of the exposed portion is changed between the outer peripheral side and the inner peripheral side of the positive electrode mixture layer.   6. The non-aqueous secondary battery according to claim 5, wherein the expansion / contraction relaxation function is formed by changing the width of the exposed portion between the winding start side and the winding end side of the positive electrode mixture layer.   6. The non-aqueous secondary according to claim 5, wherein, as the expansion / contraction relaxation function, the exposed portion is formed by changing the width of the outer peripheral side and the inner peripheral side and changing the width of the winding start side and the winding end side. battery.   The non-aqueous secondary battery according to claim 2, wherein the expansion / contraction relaxation function is formed by changing an interval between exposed portions of the positive electrode current collector.   10. The non-aqueous secondary battery according to claim 9, wherein the non-aqueous secondary battery is formed by changing an interval between exposed portions on the outer peripheral side and the inner peripheral side of the positive electrode mixture layer as the expansion / contraction relaxation function.   10. The non-aqueous secondary battery according to claim 9, wherein the expansion / contraction relaxation function is formed by changing an interval between exposed portions between a winding start side and a winding end side of the positive electrode mixture layer. 11.   10. The non-aqueous secondary battery according to claim 9, wherein as the expansion / contraction relaxation function, an exposed portion is formed by changing an interval between the outer peripheral side and the inner peripheral side and changing an interval between the winding start side and the winding end side. .   The exposed portion is formed by changing a width of an exposed portion of the positive electrode current collector or the negative electrode current collector as the expansion / contraction relaxation function and changing an interval between the exposed portions of the positive electrode current collector. Non-aqueous secondary battery.   A positive electrode plate having a positive electrode mixture layer formed by applying 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 on a positive electrode current collector; A negative electrode mixture coating material in which an active material made of a material capable of holding lithium and a binder are kneaded and dispersed in a dispersion medium is applied on the negative electrode current collector to form a porous material between the negative electrode plate and the negative electrode plate. A non-aqueous secondary battery in which an electrode group formed by winding or stacking in a spiral shape with a porous insulator interposed is enclosed in a battery case together with a non-aqueous electrolyte solution, and the expansion and contraction of the positive electrode plate is reduced. A non-aqueous secondary battery provided with an expansion / contraction relaxation function and an expansion / contraction promotion function for promoting expansion / contraction in a direction where the degree of expansion / contraction during charging / discharging of the positive electrode plate and the negative electrode plate is small.

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