JP2009193842A - Nonaqueous secondary battery, and manufacturing method and device thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of large capacity loss of a secondary battery, in a method thickening a separator thickness, since an innermost peripheral part of an electrode plate group has high curvature, and there are cutting burrs of a unformed part of a positive electrode active material mixture layer of a positive electrode plate or level differences of an end part of a forming part of the positive electrode active material mixture layer, and thus, sufficient insulation cannot be retained with only one thin separator. <P>SOLUTION: Tip parts 18 of separators 9, 10 are arranged on an inner peripheral side of a band-like negative electrode plate 7 in an innermost peripheral part of an electrode plate group 4 wound round in a spiral shape, and the tip parts 18 of the separators 9, 10 are folded and arranged to exist on an outer peripheral side of a part which is not protected by an insulation tape 25 between a forming part and a unformed part 19 of a positive electrode active material mixture layer of a band-like positive electrode plate 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithium ion secondary battery typified by a non-aqueous secondary battery, and a non-aqueous secondary battery containing an electrode plate group wound in a highly safe spiral shape that suppresses the occurrence of an internal short circuit; The present invention relates to a manufacturing method and a manufacturing apparatus thereof.

  In recent years, in the field of secondary batteries, lithium ion secondary batteries represented by non-aqueous secondary batteries that are lighter and have a higher capacity than nickel cadmium storage batteries and nickel metal hydride storage batteries have attracted attention. Secondary batteries are used as power sources for portable electronic devices. Shows significant growth in the market. In addition, with the diversification of electronic equipment and communication equipment, further increase in capacity is desired, and as the capacity increases, safety measures should be emphasized as well, especially the positive electrode plate that is a power generation element for lithium ion secondary batteries It is extremely important to suppress the generation of heat that causes a rapid temperature rise due to an internal short circuit between the negative electrode plate and the negative electrode plate. In this lithium ion secondary battery, an electrode plate group wound in a spiral shape with a separator interposed between a positive electrode plate and a negative electrode plate is housed in a battery case, and then a non-aqueous electrolyte is injected, and then a sealing body is used. It is manufactured by sealing the opening of the battery case.

  As shown in FIG. 5, in the configuration at the start of winding of the electrode plate group, the core 301 is sandwiched so that the ends of the two strip-shaped separators 302 and 303 that are overlapped are folded back. A strip-shaped positive electrode plate 304 with an insulating tape 306 attached to the boundary between the molded portion and the unmolded portion of the positive electrode active material mixture layer is wound between the separators 302 and 303. It is arranged on the inner peripheral side and wound. At this time, insulation between the outer peripheral side of the negative electrode plate 305 and the inner peripheral side of the positive electrode plate 304 is made by the separator 302, and insulation between the inner peripheral side of the negative electrode plate 305 and the outer peripheral side of the positive electrode plate 304 is made by the separator 303 and folded. The separator 307 is a useless part of the inner periphery, and from the viewpoint of effectively using a limited space, a method is proposed in which it is better to wind the turn-back length P shorter and a thinner separator thickness is more preferable. (For example, refer to Patent Document 1).

In addition, as shown in FIG. 6, between the front end portion 402 of the negative electrode plate 405 and the front end portion 408 of the separator 401, an unshaped portion 410 of the inner peripheral side of the negative electrode plate 405 and the positive electrode active material mixture layer of the positive electrode plate 407. Is separated by three separators 401, and one separator is provided between the outer peripheral side of the negative electrode plate 405 and the inner peripheral side of the unmolded portion 410 of the positive electrode active material mixture layer of the positive electrode plate 407. 401 and the positive electrode plate 407 are insulated by an insulating tape 404 affixed to an unmolded portion 410 of the positive electrode active material mixture layer. Furthermore, in the area A from the front end portion 408 of the separator 401 to the front end portion 403 of the insulating tape 404 affixed to the unformed portion 410 of the positive electrode active material mixture layer on the positive electrode plate 407, the inner peripheral side of the negative electrode plate 405 and Only one separator 401 is insulated from the outer peripheral side of the unshaped portion 410 of the positive electrode active material mixture layer of the positive electrode plate 407, and the inner periphery of the unshaped portion 410 of the positive electrode active material mixture layer of the positive electrode plate 407. The positive electrode lead 411 present in the part causes damage to the separator 401 due to burrs or the like, but the electrode plate is protected from internal short-circuit by applying insulation such as attaching a tape to the positive electrode lead 411 on the inner peripheral part of the positive electrode plate 407 A group 415 has been proposed (see, for example, Patent Document 2).
JP 07-320770 A JP-A-10-241737

However, in Patent Document 1 which is the above-described prior art, the folded separator 307 is a useless part of the inner periphery, and the folded length P is shorter from the viewpoint of effectively using a limited space. It is better to make the separators 302 and 303 thinner. However, since the innermost peripheral portion of the wound electrode plate group has a large curvature and is susceptible to stress, only one separator 303 has sufficient insulation. In order to maintain the thickness, a thickness is necessary, and there is a problem that the positive electrode plate 304 and the negative electrode plate 305 come into contact with each other due to breakage of the separator 303 in the electrode plate group or the like, and an internal short circuit is likely to occur.

  In Patent Document 2, which is a prior art, the positive electrode lead 411 is protected with an insulating tape so that burrs or the like due to the cutting of the positive electrode lead 411 do not cause the separator 401 to be damaged. In the case where only one separator 401 is insulated due to burrs generated at the longitudinal ends of the electrode plate group 415 of the unformed portion 410 of the positive electrode active material mixture layer 407, the positive electrode plate 407 is damaged due to breakage of the separator 401. There arises a problem that the unformed portion 410 of the positive electrode active material mixture layer and the negative electrode plate 405 come into contact with each other to cause an internal short circuit. Further, the negative electrode is formed by the height of the bulge at the end 409 of the molded portion 406 of the positive electrode active material layer 407 of the positive electrode plate 407 or the level difference of the active material mixture layer or the cutting burrs generated when the positive electrode plate 407 is produced. Since it is necessary to avoid the connection with the plate 405, the thickness of the separator 401 is necessary. When the thickness of the separator 401 is increased in order to improve the insulation, the proportion of the separator 401 in the electrode plate group 415 increases, Capacity tends to decrease.

  The present invention has been made in view of the above-described conventional problems, and the tip portion of the separator is folded between the unformed portion of the positive electrode active material mixture layer of the positive electrode plate on the inner peripheral portion of the electrode plate group and the negative electrode plate. In spite of the thin separator, the electrode plate group that keeps the insulation of the inner peripheral part of the electrode plate group and suppresses the occurrence of the internal short circuit by arranging multiple pieces to the danger part of the internal short circuit The object is to provide a non-aqueous secondary battery having stable battery performance.

  In order to achieve the above-described object, a positive electrode plate having a molded part and a non-molded part of the positive electrode active material mixture layer on the current collector, and a molded part of the negative electrode active material mixture layer on the current collector And an electrode plate group formed by winding a negative electrode plate having an unmolded portion in a spiral shape with a separator interposed therebetween, and a non-aqueous electrolyte solution in the battery case, and a sealing body opening portion of the battery case In the non-aqueous secondary battery in which the electrode is sealed, the tip of the separator folded back at the innermost periphery of the electrode plate group is located between the negative electrode plate and the unformed portion of the active material mixture layer of the positive electrode plate. It is characterized by.

  According to the present invention, the tip portion of the separator folded at the innermost peripheral portion of the electrode plate group is located between the negative electrode plate and the unformed portion of the positive electrode active material mixture layer of the positive electrode plate, Occurred when making the positive plate or the height of the bulge at the end of the molded part of the positive electrode active material mixture layer of the positive plate, even if it is a thin separator, insulated from the positive plate by a plurality of separators Suppressing separator breakage due to cutting burrs, etc., and preventing short circuit between positive and negative plates, non-aqueous system with high reliability and safety without causing heat generation due to internal short circuit It becomes a secondary battery.

  In the first invention of the present invention, a positive electrode plate having a molded part of the positive electrode active material mixture layer and an unmolded part on the current collector, and a molded part of the negative electrode active material mixture layer on the current collector An electrode plate group formed by winding a negative electrode plate having a molded portion in a spiral shape with a separator interposed therebetween is housed in a battery case together with a non-aqueous electrolyte, and the opening of the battery case is sealed with a sealing body. In the non-aqueous secondary battery, the tip portion of the separator folded back at the innermost peripheral portion of the electrode plate group is located between the unformed portion of the active material mixture layer of the negative electrode plate and the positive electrode plate, Non-aqueous secondary battery with stable battery performance that can interpose a plurality of separators, maintains the insulation of the inner periphery of the electrode plate group even when a thin separator is used, and suppresses the occurrence of internal short circuits It becomes.

  In the second invention of the present invention, the tip portion of the innermost peripheral separator of the electrode plate group wound in a spiral shape is disposed at a position inside the unformed portion of the negative electrode active material mixture layer of the negative electrode plate. Thus, the negative electrode plate and the positive electrode plate are insulated by a plurality of separators, and it is possible to maintain the insulation of the inner peripheral portion of the electrode plate group.

  In the third aspect of the present invention, the winding direction of the tip of the separator at the innermost peripheral portion of the electrode group wound in a spiral shape is wound in the direction opposite to the winding direction of the positive electrode plate and the negative electrode plate. As a result, the tip portion of the separator folded back at the innermost periphery of the electrode plate group can be positioned between the negative electrode plate and the unformed portion of the positive electrode active material mixture layer of the positive electrode plate, and heat is generated due to an internal short circuit. It becomes a non-aqueous secondary battery with high reliability and safety that does not reach the above.

  In the fourth invention of the present invention, a strip-like positive electrode plate in which a molded portion of a positive electrode active material mixture layer coated with a positive electrode active material mixture on a current collector and an uncoated portion not coated are molded And a strip-shaped negative electrode plate in which a negative electrode active material mixture layer coated with a negative electrode active material mixture is formed on a current collector and a non-coated non-coated portion is formed on the current collector. After the electrode plate group formed by winding in a spiral shape is stored in the battery case, the nonaqueous electrolyte is injected, the sealing body is placed on the opening of the battery case, and the opening of the battery case is caulked and sealed In the method for manufacturing a non-aqueous secondary battery, when the electrode plate group is wound, the front end portion of the separator is folded back, and the front end portion of the negative electrode plate is folded back while holding the front end portion of the separator at a predetermined length. The positive electrode active material of the negative electrode plate and the positive electrode plate is arranged and wound on the outer peripheral side of the separator. Can place distal portion of the separator between the unmolded parts of the adhesive layer, the distal end portion of the separator can be utilized without waste effective folded.

  5th invention of this invention WHEREIN: The strip | belt-shaped positive electrode plate which had the shaping | molding part and unshaped part of the positive electrode active material mixture layer on the electrical power collector, and the shaping | molding part of the negative electrode active material mixture layer on the electrical power collector A non-electrolytic solution is housed in the battery case together with a non-aqueous electrolyte solution in which the electrode plate group obtained by spirally winding a strip-shaped negative electrode plate having a non-molded portion through a separator is sealed, and the opening of the battery case is sealed with a sealing body An apparatus for manufacturing an aqueous secondary battery includes a positive electrode unwinding unit that supplies a positive electrode plate, a negative electrode plate unwinding unit that supplies a negative electrode plate, and a separator unwinding unit that supplies a separator. A sandwiching part to be sandwiched, a holding part that keeps the front end part of the separator at a predetermined length when the electrode plate group is wound, a winding part that is wound in a spiral after the front end part of the separator is folded, and a negative electrode plate To place the tip of the separator on the outer periphery of the folded separator By comprising the intrusion guide portion that assists the negative electrode plate, it becomes possible to reliably arrange the tip portion of the separator between the negative electrode plate and the unformed portion of the positive electrode active material mixture layer of the positive electrode plate. It is possible to prevent the front end portion of the separator from being caught in the front end portion of the folded separator.

  In the sixth aspect of the present invention, as the holding portion, a length measuring portion for measuring a predetermined length of the front end portion of the separator by controlling a feeding amount of the separator, and a front end portion of the separator are cut into a predetermined length. By forming the cutting portion and the separator pressing portion that assists holding the tip portion of the separator, the minimum required predetermined length of the tip portion of the separator can be efficiently suppressed, and productivity can be improved. .

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional perspective view of a lithium ion secondary battery according to an embodiment of the present invention, and a positive electrode plate 5 using a composite lithium oxide as an active material and a negative electrode plate using a material capable of holding lithium as an active material. 7 is spirally wound through separators 9 and 10, and the electrode plate group 4 is housed inside the bottomed cylindrical battery case 1 together with the insulating plate 15. A positive electrode lead 6 led out from the upper part of the electrode plate group 4 is connected to the sealing plate 2, and a non-aqueous electrolyte solution (not shown) made of a predetermined amount of non-aqueous solvent is stored in the battery case 1. A sealing plate 2 having a sealing gasket 3 attached to the periphery thereof is placed on the opening of the battery case 1, and the opening of the battery case 1 is folded inward to be caulked and sealed.

  Next, FIG. 2 is an enlarged cross-sectional view showing the innermost peripheral portion of the electrode plate group 4 in one embodiment of the present invention. As shown in FIG. 2, the positive electrode active material mixture layer of the positive electrode plate 5 covers the tip portion 30 of the molded portion 24 of the positive electrode active material mixture layer of the positive electrode plate 5 on the inner peripheral side and outer peripheral side of the positive electrode plate 5. Insulating tape 25 is applied together with a part of the unshaped part 19 of the negative electrode 7, and the molded part 26 of the negative electrode active material mixture layer of the negative electrode plate 7 from the tip part 22 of the unshaped part 20 of the negative electrode active material mixture layer of the negative electrode plate 7. Until the position where the terminal portion 28 of the insulating tape 25 affixed to the positive electrode plate 5 exists on the outer peripheral side, the insulating tape 25 is present in addition to the one separator 10 interposed. In addition, the outer peripheral side of the positive electrode plate 5 between the molded portion 24 of the positive electrode active material mixture layer of the positive electrode plate 5 and the end portion 28 of the insulating tape 25 affixed to a part of the unmolded portion 19. And the inner peripheral side of the negative electrode plate 7, there is an insulating tape 25 in addition to a single separator 9.

  Further, the outer peripheral side of the positive electrode plate 5 and the negative electrode plate 7 from the start end portion 29 of the insulating tape 25 to the tip portion 23 of the unformed portion 19 of the positive electrode active material mixture layer of the positive electrode plate 5 to which the positive electrode lead 6 is connected. In between, there are a total of three separators including the separators 9 and 10 in which the tip portions 18 of the separators 9 and 10 are folded back in the direction opposite to the winding direction of the positive electrode plate 5 and the negative electrode plate 7. The curvature of the innermost peripheral portion of the wound electrode plate group 4 in which the tip end portions 18 of the folded separators 9 and 10 are arranged inside the unformed portion 20 of the negative electrode active material mixture layer of the negative electrode plate 7 is wound. The total thickness of the separator capable of maintaining sufficient insulation even when subjected to stress generated by the above is obtained, and the tip portion 23 of the unmolded portion 19 of the positive electrode active material mixture layer of the positive electrode plate 5 and the negative electrode plate 7 It is possible to suppress an internal short circuit due to contact with the tip portion 22 of the unmolded portion 20 of the negative electrode active material mixture layer.

  Thus, in the electrode group in one embodiment of the present invention, the insulation between the unformed portion of the positive electrode active material active material mixture layer of the positive electrode plate and the negative electrode plate is composed of three separators or one separator and an insulating tape. It becomes a state of one sheet, and there is no portion where the separator existing in the electrode plate group of the prior art is insulated by only one sheet, and insulation can be maintained even if the separator is thinner than the prior art. The thickness of the separator includes a cutting burr that occurs when the positive electrode plate is cut into a strip shape, a step at the tip of the mixture molding portion of the positive electrode plate, and so on. Although it is necessary, in the electrode plate group in one embodiment of the present invention, since there are three separators, it is possible to use a separator with a thin separator thickness, which is limited in the battery case of the non-aqueous secondary battery. Space can be used more effectively.

  Hereinafter, Example 1 of the present invention will be described in detail, but the present invention is not limited to the following. First, although it does not specifically limit about the positive electrode plate 5 shown in FIG. 1, The foil, nonwoven fabric, etc. which are made from aluminum or aluminum alloy can be used, the foil made from aluminum alloy, and the thickness of foil is 5 micrometers-30 micrometers. A positive electrode active material, a conductive material, and a binder are mixed and dispersed in a dispersion medium with a dispersing machine such as a planetary mixer on both sides of the current collector. The positive electrode plate 5 was produced by forming an active material mixture layer.

As the positive electrode active material, lithium cobaltate and modified products thereof (such as lithium cobaltate in which aluminum or magnesium is dissolved), for example, lithium nickelate and modified products thereof (partly nickel-substituted cobalt) Etc.), and complex oxides such as lithium manganate and modified products thereof. As the conductive material at this time, acetylene black is used. For example, carbon black such as ketjen black, channel black, furnace black, lamp black, thermal black, and various graphites may be used alone or in combination. As the binder, polyvinylidene fluoride (PVdF) can be used. For example, 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 into which a reactive functional group is introduced into the binder.

  On the other hand, although it does not specifically limit about the negative electrode plate 7, rolled copper foil, electrolytic copper foil, the nonwoven fabric of copper fiber, etc. can be used, In Example 1 of this invention, rolled copper foil is used and the thickness of foil is 5 micrometers- A negative electrode current collector having a thickness of 25 μm was mixed with a negative electrode active material, a binder, and optionally a conductive material and a thickener in a dispersion medium by a dispersing machine such as a planetary mixer. A negative electrode plate 7 was prepared by applying a coating agent, drying and rolling to form a negative electrode active material active material mixture layer.

  As the negative electrode active material, natural graphite and artificial graphite can be used, and silicon-based composite materials such as silicide and various alloy composition materials can also be used. As the binder for the negative electrode at this time, a binder of PVdF can be used, and various binders including PVdF and modified products thereof can be used. From the viewpoint of improving lithium ion acceptability, styrene-butadiene copolymer rubber particles (SBR) and modified products thereof can also be used. As the thickener, polyethylene oxide (PEO) is used, and there is no particular limitation as long as it is a material having viscosity as an aqueous solution such as polyvinyl alcohol (PVA). However, cellulose resins such as carboxymethyl cellulose (CMC) and their modification are not limited. The body is preferable from the viewpoint of dispersibility and thickening of the mixture paint.

As for the electrolytic solution, a LiPF ₆ used as an electrolyte salt, for example may be any of various lithium compounds such as LiBF _4. Further, although ethylene carbonate (EC) was used as a solvent, dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC) can be used alone or in combination. It is also preferable to use vinylene carbonate (VC), cyclohexylbenzene (CHB), or a modified product thereof in order to form a good film on the positive and negative electrode plates or to ensure stability during overcharge.

  As the separator, polyethylene is used, for example, polypropylene, PVdF, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, PTFE, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyether (PEO or polypropylene oxide), cellulose (carboxymethylcellulose, It is also preferable to use a microporous film made of a polymer such as hydroxypropylcellulose), poly (meth) acrylic acid, poly (meth) acrylic acid ester. In addition, a multilayer film in which these microporous films are superposed is also possible, and among them, a microporous film made of polyethylene, polypropylene, PVdF or the like is suitable, and the thickness is preferably 10 μm to 25 μm. In Example 1, the thickness is 20 μm. A thick separator was used.

  As the battery case 1, a bottomed cylindrical or rectangular battery case having an open top can be used. In the present invention, a bottomed cylindrical shape is used, and the steel plate is nickel-plated as the material. Was used. Other materials include those made of an aluminum alloy.

  Next, a manufacturing method and a manufacturing apparatus for a nonaqueous secondary battery according to Example 1 of the present invention will be described with reference to the drawings. FIG. 3 is a schematic diagram of a secondary battery manufacturing apparatus according to Embodiment 1 of the present invention. In addition, Example 1 of this invention below does not limit this invention.

First, a strip-like positive electrode plate 5 in which a positive electrode active material mixture containing at least a positive electrode active material is applied to a positive electrode current collector and a negative electrode active material mixture containing an active material capable of holding lithium are applied to a negative electrode current collector. The strip-shaped negative electrode plate 7 and the strip-shaped separator 9 and the separator 10 are in the hoop state, respectively, the unwinding portion 44 of the positive electrode plate 5, the unwinding portion 42 of the negative electrode plate 7, the unwinding portion 43 of the separator 9, and the winding of the separator 10 A protruding portion 45 is arranged. The strip-shaped positive electrode plate 5 drawn out from the unwinding portion 44, the strip-shaped negative electrode plate 7 pulled out from the unwinding portion 42, the strip-shaped separator 9 pulled out from the unwinding portion 43 or the unwinding portion 44, and the separator 10 Is wound in a spiral shape at the winding portion 46 to produce the electrode plate group 4 shown in FIG.

  In addition, the winding portion 46 is provided with a winding core 32 through which the separators 9 and 10 pass through a central portion divided into two, and a rush guide portion 31 that assists in winding the negative electrode plate 7 into the winding core 32. Further, above the winding portion 46, a nip roller 35 as a sandwiching portion is disposed so as to sandwich the separators 9 and 10 and the positive electrode plate 5 and the negative electrode plate 7, and below the winding portion 46, the separators 9 and 10 A separator cutter 33 that is a cutting portion that cuts the tip end portion 18 with a predetermined length; a separator presser portion 34 that is a holding portion that holds the tip portions 18 of the separators 9 and 10 at a predetermined length; and a presser block 41; Further, between the nip roller 35 and the unwinding portion 43 of the separator 9, a separator length measuring encoder 40 which is a length measuring portion for measuring the feed amount of the separator 9 is disposed.

  Further, the winding part 46 will be described in more detail with reference to the drawings. As shown in FIG. 4, the core 32 has a two-part structure, and the leading end portion 18 of the separators 9, 10 is sandwiched between the center parts of the cores 32 divided into two parts, and is sandwiched between the separators 9, 10. The positive electrode plate 5 is arranged so that the positive electrode plate 5 is composed of a molded part 24 coated with a positive electrode active material mixture layer and an unmolded part 19 not coated with the positive electrode active material mixture layer. An insulating tape 25 is affixed to the boundary between 24 and the unmolded portion 19. Further, a positive electrode lead is welded to the unmolded portion 19 of the positive electrode active material mixture layer of the positive electrode plate 5. Further, the negative electrode plate 7 is disposed with the positive electrode plate 5 and the separator 10 interposed therebetween, and the negative electrode plate 7 is composed of a molded portion 26 coated with the negative electrode active material mixture layer and an unmolded portion 20 not coated. .

  Next, the operation content in Example 1 of this invention is demonstrated using FIG. 3 and FIG. As shown in FIG. 3, the strip-shaped positive electrode plate 5 drawn from the unwinding portion 44, the strip-shaped negative electrode plate 7 pulled out from the unwinding portion 42, the unwinding portion 43, and the strip-shaped separator pulled out from the unwinding portion 44. 9. The separator 10 is sandwiched between the nip rollers 35, and the leading end portions 18 of the separators 9 and 10 are sandwiched between the two divided portions of the core 32. At that time, a predetermined length for turning back the tip end portions 18 of the separators 9 and 10 is determined by the position at which the tip end portions 18 of the separators 9 and 10 are cut, that is, the position of the core 32 to the separator cutter 33. The position of the separator cutter 33 is movable and can be adjusted. It is also possible to determine the length of the tip end portion 18 of the separators 9 and 10 by measuring the feed amount with the separator measuring encoder 40.

  Next, in a state where the separators 9 and 10 are sandwiched between the winding cores 32, the leading end portions 18 of the separators 9 and 10 are sandwiched between the separator pressing portion 34 and the pressing block 41 and then cut by the separator cutter 33. Thereafter, as shown in FIG. 4, the core 32 is rotated halfway in the direction of the arrow, and the tip portions 18 of the separators 9 and 10 are folded back. At this time, when the separator presser 34 is kept pressed, the tip end portions 18 of the separators 9 and 10 on the folding side are not wound around the core 32, and the separator 9 on the side wound together with the positive electrode plate 5 and the negative electrode plate 7. , 10 is wound. When the winding core 32 is rotated by a half circumference, the separators 9 and 10 on the side wound together with the positive electrode plate 5 and the negative electrode plate 7 are pressed from the outer peripheral side of the tip end portions 18 of the separators 9 and 10 on the folding side, Ten tip portions 18 also begin to wind.

  At this time, if the tip end portion 18 of the separators 9 and 10 is kept pressed by the separator presser 34, the core 32 is pulled halfway around the separator presser 34 in order to prevent the winding core 32 from being bent and to cause winding slippage. It is released when it has rotated more than one revolution. The timing at which the separator presser 34 is released is measured when the feed amount is measured by the separator measuring encoder 40 provided between the nip roller 35 and the unwinding portion 43 of the separator 9, and the tip end portions 18 of the separators 9 and 10 are folded back. To release the separator presser 34.

  That is, in the present invention, the pressing of the tip end portion 18 of the separators 9 and 10 is held until the winding core 32 rotates more than half a turn, and the winding core 32 is opened after a half turn and is turned and folded. The length L can be maintained at a predetermined length. Further, until the winding core 32 is rotated half a turn, the feeding amount of the separators 9 and 10 is reliably measured, the front end portions 18 of the separators 9 and 10 are sufficiently held, and the front end portions of the separators 9 and 10 are turned back. The length L of 18 is suppressed so as not to be shorter than a predetermined length.

  Next, the winding core 32 is rotated in the direction of the arrow shown in FIG. 4, the separators 9 and 10 are wound, and the unformed portion 19 of the positive electrode active material mixture layer of the positive electrode plate 5 disposed between the separators 9 and 10. Begin to wind the tip portion 23. When winding the negative electrode plate 7, the tip portion 22 of the unmolded portion 20 of the negative electrode active material mixture layer of the negative electrode plate 7 is pressed by the intrusion guide portion 31 so as to approach the separator 10 to assist. Further, the positive electrode plate 5, the negative electrode plate 7, and the separators 9 and 10 are wound while being sandwiched by the nip rollers 35 until the leading end portion 23 of the positive electrode plate 5 and the leading end portion 22 of the negative electrode plate 7 start to be wound. Further, the winding core 32 was rotated to produce the electrode plate group 4 as shown in FIG. 2 and housed in the battery case 1 shown in FIG. 1 to produce a non-aqueous secondary battery.

  The separator tip portion folded back at the innermost periphery of the electrode plate group according to the present invention is positioned between the negative electrode plate and the unformed portion of the positive electrode active material mixture layer of the positive electrode plate, Can be insulated with a plurality of separators to prevent a short circuit between the positive electrode plate and the negative electrode plate, resulting in a highly reliable and safe non-aqueous secondary battery that does not cause heat generation due to an internal short circuit. .

  In the non-aqueous secondary battery according to the present invention, the front end portion of the separator folded back at the innermost peripheral portion of the electrode plate group is located between the negative electrode plate and the unformed portion of the active material active material mixture layer of the positive electrode plate. This makes it possible to diversify electronic equipment and communication equipment because it is highly reliable and safe in that it has high insulation at the inner periphery with high curvature and is difficult to cause an internal short circuit even when a thin separator is used. Accordingly, it is desired to further increase the capacity, and it is useful as a non-aqueous secondary battery in which safety is emphasized while the capacity is increased.

Sectional cutaway perspective view of a non-aqueous secondary battery in an embodiment of the present invention Enlarged cross-sectional schematic view of the inner periphery of the electrode plate group in the embodiment of the present invention The schematic diagram of the manufacturing apparatus of the non-aqueous secondary battery in embodiment of this invention The schematic diagram of the winding part in embodiment of this invention Schematic diagram of the winding part in the prior art Enlarged cross-sectional schematic diagram of the inner periphery of a conventional electrode plate group

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Sealing plate 3 Sealing gasket 4 Electrode plate group 5 Positive electrode plate 6 Positive electrode lead 7 Negative electrode plate 8 Negative electrode lead 9 Separator 10 Separator 15 Insulating plate 18 Tip part 19 Unmolded part 20 Unmolded part 22 Tip part 23 Tip part 24 Molded portion 25 Insulating tape 26 Molded portion 28 Terminating portion 29 Start end portion 30 Tip portion 31 Entry guide portion 32 Core 33 Separator cutter 34 Separator pressing portion 35 Nip roller 40 Separator length measuring encoder 41 Pressing block 42 Unwinding portion 43 Unwinding portion 44 Unwinding part 45 Unwinding part 46 Winding part L Length of tip part

Claims (6)

  A positive electrode plate having a molded portion and an unmolded portion of the positive electrode active material mixture layer on the current collector, and a negative electrode plate having a molded portion and an unmolded portion of the negative electrode active material mixture layer on the current collector. In a non-aqueous secondary battery in which a group of electrode plates wound in a spiral shape with a separator interposed therebetween is housed in a battery case together with a non-aqueous electrolyte, and the opening of the battery case is sealed with a sealing body, A non-aqueous two-phase structure characterized in that a front end portion of the separator folded back at an innermost peripheral portion of the electrode plate group is located between an unformed portion of the active material mixture layer of the negative electrode plate and the positive electrode plate. Next battery.   The tip portion of the separator at the innermost peripheral portion of the electrode group wound in a spiral shape is disposed at a position inside the unformed portion of the negative electrode active material mixture layer of the negative electrode plate. Item 2. The nonaqueous secondary battery according to Item 1.   The winding direction of the tip portion of the separator at the innermost peripheral portion of the electrode group wound in a spiral shape is wound in a direction opposite to the winding direction of the positive electrode plate and the negative electrode plate. The non-aqueous secondary battery according to claim 1.   A positive electrode active material mixture layer coated with a positive electrode active material mixture on the current collector and a strip-shaped positive electrode plate formed with a non-coated portion coated with a positive electrode active material mixture, and a negative electrode active material on the current collector Formed by spirally winding a separator between a formed part of the negative electrode active material mixture layer coated with the material mixture and a strip-shaped negative electrode plate formed with the uncoated part not coated Of the non-aqueous secondary battery in which the electrode plate group is stored in the battery case, a non-aqueous electrolyte is injected, a sealing body is placed on the opening of the battery case, and the opening of the battery case is caulked and sealed. In the manufacturing method, when the electrode plate group is wound, the outer periphery of the separator is folded back while the tip end portion of the negative electrode plate is folded back while holding the tip end portion of the separator at a predetermined length. A method for producing a non-aqueous secondary battery, wherein the method is arranged and wound around.   A strip-shaped positive electrode plate having a molded portion and an unmolded portion of the positive electrode active material mixture layer on the current collector, and a strip-shaped positive plate having a molded portion and an unmolded portion of the negative electrode active material mixture layer on the current collector In an apparatus for producing a non-aqueous secondary battery in which a group of electrode plates in which a negative electrode plate is spirally wound through a separator is housed in a battery case together with a non-aqueous electrolyte, and the opening of the battery case is sealed with a sealing body A positive electrode unwinding section for supplying the positive electrode plate, an unwinding section for the negative electrode plate for supplying the negative electrode plate, and an unwinding section for the separator for supplying the separator, and sandwiching the positive electrode plate, the negative electrode plate and the separator at the same time A holding part, a holding part that keeps the front end part of the separator at a predetermined length when the electrode plate group is wound, and a winding part that is wound in a spiral shape after folding the front end part of the separator; The outside of the separator folded back at the tip of the negative electrode plate Nonaqueous secondary battery manufacturing apparatus characterized by being configured inrush guide section for assisting the negative electrode plate for placement into the side.   As the holding part, a length measuring part for measuring a predetermined length of the front end part of the separator by controlling a feeding amount of the separator, a cutting part for cutting the front end part of the separator to a predetermined length, 6. The non-aqueous secondary battery manufacturing apparatus according to claim 5, wherein the non-aqueous secondary battery manufacturing apparatus comprises a separator pressing portion that assists in holding the tip portion of the separator.

Images