JP5222030B2 - Winding type secondary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wound secondary battery and a method for manufacturing the same, and in particular, a wound group in which a positive electrode plate and a negative electrode plate are wound through a separator, an electrolyte solution infiltrating the wound group, and a wound group The present invention relates to a wound secondary battery including a battery container that houses a battery and an electrolytic solution, and a method for manufacturing the same.

  Conventionally, in a wound secondary battery, a wound group in which a positive electrode plate and a negative electrode plate are wound in a spiral shape through a separator is housed in a cylindrical container. In general, the wound group is wound around the core while applying tension to the positive and negative electrode plates and the separator in order to prevent twisting. Among such wound secondary batteries, cylindrical lithium secondary batteries are widely used in portable devices such as VTR cameras, notebook personal computers, and mobile phones, taking advantage of the high energy density. Moreover, it is used also as the vehicle-mounted power supply etc. of an electric vehicle (EV) or a hybrid electric vehicle (HEV) as a secondary battery for large current charge / discharge applications.

  In a secondary battery for large current charge / discharge applications, a module in which a large number (for example, 40 to 100) of cylindrical batteries are connected in series is usually used. However, since a gap is formed between adjacent cylindrical batteries, there is a problem that the volume efficiency of the module is impaired. In order to solve this problem, for example, a wound secondary battery is disclosed in which a wound group in which a positive electrode plate and a negative electrode plate are wound in a flat shape via a separator is contained in a rectangular parallelepiped container ( Patent Document 1).

  By the way, in order to improve the volume efficiency of a single battery, it is effective to make the core thin or not use the core. In this regard, in Patent Document 1, a so-called air core winding group that does not use a core is manufactured and accommodated in a rectangular parallelepiped container.

JP 2003-249423 A

  However, the wound secondary battery of Patent Document 1 does not use a wound core, so it is difficult to support the wound group. For example, in a battery used for a power source of an electric vehicle or the like, there is a high possibility that the winding group will be displaced or damaged due to vibration, and a short circuit between the positive and negative electrode plates may occur. For this reason, it is desirable to have a member for supporting the wound group inside the battery in consideration of vibration of an electric vehicle or the like, but when a new support member is used, the volume efficiency of the single battery is reduced. It will be. If the core used in the wound group can function as a support member, the earthquake resistance can be improved without reducing the volume efficiency. On the other hand, as described above, if the core is made thin in order to improve the volume efficiency of a single battery, the core will bend without being able to withstand the tension applied to the positive and negative electrode plates and the separator during winding, and an appropriate flat shape You will not be able to get the wound group. If the tension applied to the positive and negative electrode plates and the separator during winding is weakened, warpage of the core can be suppressed, but in this case, there is a high possibility that a twisting deviation occurs due to vibration or the like.

  An object of the present invention is to provide a wound secondary battery capable of improving volume efficiency and earthquake resistance and a method for manufacturing the same.

In order to solve the above-described problems, a first aspect of the present invention is a wound secondary battery, in which tension is applied to each of a positive electrode plate, a negative electrode plate, and a separator, and a plate-like non-conductor core. a winding group in which the said positive electrode plate to the winding core under tension in the winding axis direction and the negative electrode plate were wound into a flat shape through the separator, and an electrolyte to infiltrate the winding assembly, The winding group and a battery container that stores the electrolyte solution , wherein the tension applied to the core is equal to or greater than the total tension applied to the positive and negative electrode plates and the separator. And

In a first aspect, the positive electrode plate, with tension to the negative electrode plate and a separator, while applying a tension of the winding axis direction to the winding core and the positive and negative electrode plates are wound in a flat shape via a separator Since the tension applied to the core is equal to or greater than the total tension applied to the positive and negative electrode plates and the separator, deformation of the core during winding is suppressed. The efficiency can be improved, and the segregation of the positive and negative electrode plates and the separator with respect to the core is suppressed, so that the earthquake resistance can be improved.

1st aspect WHEREIN: The to-be-attached part for mounting | wearing a winding core with a winding apparatus may be formed in the winding axial direction both ends of a winding core .

According to a second aspect of the present invention, there is provided a method for manufacturing a wound secondary battery according to the first aspect, wherein a mounting step of mounting a plate-like, non-conductive core on the winding device; Winding that applies tension to each of the negative electrode plate and the separator and winds the positive electrode plate and the negative electrode plate in a flat shape through the separator while applying tension in the winding axis direction to the core. It viewed including the steps, and in the winding step, the magnitude of the tension applied to the said winding core, characterized in that said positive and negative electrode plates and the separator to the sum over tension multiplied respectively. In this case, in the mounting step, the mounted portions formed at both ends of the winding core in the winding axis direction and the mounting portions provided in the winding device may be brought into contact with each other.

According to the present invention , the positive electrode plate, the negative electrode plate, and the separator are each tensioned, and the positive electrode plate and the negative electrode plate are wound in a flat shape through the separator while applying tension in the winding axis direction to the core. Since the tension applied to the core is equal to or greater than the total tension applied to the positive and negative electrode plates and the separator, deformation of the core during winding is suppressed. The efficiency can be improved, and the positive and negative electrode plates and the separator are prevented from slipping with respect to the core, so that the effect of improving the earthquake resistance can be obtained.

  Hereinafter, embodiments of a flat lithium secondary battery to which the present invention is applied will be described with reference to the drawings.

(Constitution)
As shown in FIG. 1, the flat lithium secondary battery 20 of the present embodiment has a rectangular parallelepiped aluminum alloy battery can (part of a battery container) 11. A wound group 1 is housed inside the battery can 11.

  As shown in FIG. 2, the wound group 1 has a plate-like and non-conductive core 4. A positive and negative electrode plate is wound in a flat shape through a separator at the center of the core 4. The positive and negative electrode plates and the separator constitute the electrode group 2. The end of the separator located on the outermost periphery of the electrode group 2 is fixed with a tacking tape 3 to prevent unraveling. When the winding group 1 is wound, tension is applied to the positive and negative electrode plates and the separator, and the winding core 4 is wound while applying tension in the winding axis direction. At this time, the magnitude of the tension applied to the core 4 is set to be equal to or greater than the total tension applied to the positive and negative electrode plates and the separator. In this example, the core 4 has a plate shape with a length in the winding axis direction of 100 mm, a width in the winding direction of 74 mm, and a thickness of 2 mm, and uses an electrically insulating member made of polypropylene. The end portion in the rotation direction is rounded to prevent breakage of the separator or the like. At both ends of the winding core 4 in the winding axis direction, circular openings (attached portions) 5 for mounting on the winding device are formed at two locations, respectively, for a total of four locations. It penetrates the core 4. The two openings 5 are respectively formed at positions symmetrical with respect to the winding axis.

  As shown in FIG. 1, a positive electrode current collector plate (not shown) made of an aluminum alloy is joined to the inner bottom surface of the battery can 11. The lower end in the winding axis direction of the core 4 is bonded and fixed to the upper surface of the central portion of the positive electrode current collector plate. The other end of the positive electrode lead plate 15 having one end bonded to the positive electrode plate is bonded to the upper surface of the peripheral edge of the positive electrode current collector plate. Therefore, the battery can 11 also serves as a positive electrode external terminal.

  In addition, a copper battery lid 10 having a hat shape in cross section is disposed on the battery can 11. On the upper side of the outer edge of the battery lid 10, an upper cover 12 made of an aluminum alloy having a rectangular flat plate and a rectangular opening formed in the center is disposed, and the outer edge of the upper lid 12 is welded to the battery can 11. The battery lid 10 is sandwiched between an inner edge portion of the upper lid 12 and a member having an L-shaped cross section fixed to the lower side of the inner edge portion via an insulator 13 made of propylene resin. In other words, the battery lid 10 is fixed to the upper part of the battery can 11 via the insulator 13 and the upper lid 12. The lower surface of the central portion of the battery lid 10 is bonded and fixed to the upper end of the winding core 4 in the winding axis direction, and the negative electrode lead plate 14 having one end bonded to the negative electrode plate is attached to the lower surface of the peripheral portion of the battery lid 10. The other end is joined. Accordingly, the protruding portion protruding from the upper portion of the battery lid 10 also serves as the negative electrode external terminal.

  The positive electrode plate constituting the electrode group 2 is a belt-like aluminum alloy foil having a thickness of 20 μm, and a mixture containing lithium manganate as a positive electrode active material is applied to both surfaces. A non-coating portion of the mixture is formed on one side along the longitudinal direction of the aluminum alloy foil. A positive electrode lead plate 15 is joined to the uncoated portion. On the other hand, the negative electrode plate is coated with a mixture containing amorphous carbon powder of the negative electrode active material on both sides of a strip-like copper foil having a thickness of 10 μm, and no mixture is coated on one side along the longitudinal direction. A landing part is formed. A negative electrode lead plate 14 is joined to the non-coated portion in the same manner as the positive electrode plate. As the separator, a polyethylene microporous film having a band shape and a thickness of 25 μm is used. The positive electrode lead plate 15 and the negative electrode lead plate 14 are disposed on opposite sides of the electrode group 2.

The outer edge of the upper lid 12 is welded to the upper end surface of the battery can 11, and the lithium secondary battery 20 is sealed. In addition, a non-aqueous electrolyte solution (not shown) in an amount capable of infiltrating the entire electrode group 2 is injected into the battery can 11. In the non-aqueous electrolyte, 1 mol of lithium hexafluorophosphate (LiPF ₆ ) is mixed in a mixed solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC), which are organic solvents, are mixed at a volume ratio of 1: 2. A solution dissolved at a concentration of 1 liter is used.

(Manufacture of lithium secondary batteries)
The lithium secondary battery 20 includes a preparation step of preparing a positive and negative electrode mixture to produce a positive and negative electrode plate, a winding step of attaching the winding core 4 to a winding device and winding the positive and negative electrode plates through a separator, The winding group 1 is housed in a battery can 11 and is manufactured by an assembly process for completing the lithium secondary battery 20. Hereinafter, it demonstrates in order of a process.

  In the preparation step, lithium manganate powder as the positive electrode active material, flaky graphite as the conductive material, and polyvinylidene fluoride as the binder (hereinafter abbreviated as PVDF) at a mass ratio of 85: 10: 5. A positive electrode mixture is prepared by mixing. Using N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) as the viscosity adjusting solvent, the positive electrode mixture is kneaded substantially uniformly to prepare a mixture slurry. The mixture slurry is applied to both sides of the aluminum alloy foil. After drying, pressing is performed to cut the width of the coated portion of the mixture to 86 mm and the width of the uncoated portion to 17 mm to produce a positive electrode plate. Moreover, the negative electrode mixture is prepared by mixing the amorphous carbon powder of the negative electrode active material and the PVDF of the binder at a mass ratio of 90:10. A negative electrode mixture is kneaded substantially uniformly using NMP to prepare a mixture slurry. The mixture slurry is applied to both sides of the strip-shaped copper foil, dried and pressed, and the width of the coated portion is cut to 88 mm and the width of the non-coated portion is cut to 15 mm to produce a negative electrode plate. Each of the produced positive and negative electrode plates is scraped off into a hoop shape.

  The winding process includes an attaching step for attaching the winding core 4 to the winding device and a winding step for fixing the winding start end of the separator to the winding core 4 and winding the positive and negative electrode plates through the separator. Composed.

  Here, the winding device will be described. The winding device has a pair of jigs for fixing the winding core 4 at both ends in the winding axis direction. As shown in FIG. 3, the jig 6 is formed in a U-shaped cross section in which a gap for inserting both ends of the winding core 4 in the winding axis direction is formed. The interval of the gap can be arbitrarily set according to the thickness of the core 4. Further, the jig 6 is formed with an opening having the same shape as the opening 5 so as to match the position of the opening 5 formed in the core 4 when the core 4 is inserted into the gap. When the core 4 is fixed to the jig 6, a pin 7 is used. The pin 7 is formed in a T-shaped cross section having a protruding portion having a shape matching the opening 5 of the core 4 and the opening of the jig 6 and a fixing portion for fixing to the jig 6. The fixed part of the pin 7 is formed with a larger diameter than the protrusion. The hole on one side of the jig 6 is provided with a recess so that the fixing portion of the pin 7 cannot be fitted. Further, the winding device includes a mechanism for applying tension in the winding axis direction T to the winding core 4 and a mechanism for rotating the jig 6 in the winding direction R. The tension applied in the winding axis direction T and the rotation speed in the winding direction R can be arbitrarily set.

  In the mounting step, both ends of the winding core 4 in the winding axis direction are inserted into the gaps of the jig 6 of the winding device described above. The protruding portion of the pin 7 is inserted into the opening 5 of the core 4 and the opening of the jig 6. At this time, the fixing portion of the pin 7 is fitted into the recess of the jig 6.

  In the winding step, the winding start end portions of the two separators are fixed to the core 4 by heat welding or the like. A tension of 5 N is applied to each of the two separators, and the separator is wound around the core 4 about 2-3 times while tension is applied to the core 4 in the winding axis direction T in the range of 10 to 100 N. The winding start end portions of the positive electrode plate and the negative electrode plate are sandwiched between the separators so that the mixture-uncoated portion of the positive and negative electrode plates is positioned on the opposite side of the winding core 4 in the winding axis direction. Each of the positive electrode plate and the negative electrode plate is applied with a tension of 8N, and each of the two separators is applied with a tension of 5N. Through the core 4. After winding a positive electrode plate and a negative electrode plate of a desired length, the positive electrode plate and the negative electrode plate are cut. After winding only the separator around 2-3 times, the separator is cut. The winding end portion of the separator is fixed with the tacking tape 3.

  In the assembling process, one end portions of the positive electrode lead plate 15 and the negative electrode lead plate 14 are joined to the uncoated portions of the positive electrode plate and the negative electrode plate positioned at both ends of the electrode group 2 in the winding axis direction, respectively. The lower end in the winding axis direction of the core 4 is bonded and fixed to the upper surface of the central portion of the positive electrode current collector plate (not shown). The other end portion of the positive electrode lead plate 15 is joined to the upper surface of the outer edge portion of the positive electrode current collector plate. Similarly, the other end portion of the negative electrode lead plate 14 is joined to the lower surface of the outer edge portion of the battery lid 10. The wound group 1 is accommodated in the battery can 11, and the lower surface of the positive electrode current collector plate is joined to the inner bottom surface of the battery can 11. After injecting the non-aqueous electrolyte, the battery lid 10 is disposed on the upper portion of the battery can 11 via the insulator 13, and the lower surface of the central portion of the battery lid 10 is bonded and fixed to the upper end in the winding axis direction of the core 4. The outer edge of the upper lid 12 is welded to the upper end surface of the battery can 11 to seal and complete the lithium secondary battery 20.

  Next, examples of the lithium secondary battery 20 manufactured according to the present embodiment will be described. A comparative example prepared for comparison is also shown.

( Reference Example 1, Reference Example 2, Example 3 to Example 6)
In Reference Example 1, Reference Example 2, and Examples 3 to 6, as shown in Table 1 below, the magnitude of tension in the winding axis direction T applied to the core 4 (hereinafter referred to as core tension). ) Was changed to produce a lithium secondary battery 20. Winding core tension, respectively, in Reference Example 1 10 N, Reference Example 2, 20 N, Example 3 30 N, in Example 4 50 N, in Example 5 70N, was set to 100N in Example 6.

(Comparative example)
In the comparative example, a wound group was prepared in the same manner as in Example 3, and then the core was taken out to prepare a lithium secondary battery.

(Evaluation)
Fifty lithium secondary batteries of each of the examples , reference examples, and comparative examples were produced, and each was charged to a fully charged state. About the lithium secondary battery of each example , reference example, and comparative example, using a vibration tester (Emic Co., Ltd., F1400BDH / LA-E type), a vibration test of 10G · 100 hours was performed, Short-circuit occurrence rate, smoke generation rate and ignition rate were measured. Each measurement result is shown in Table 1. Each occurrence rate represents a ratio of short circuit, smoke generation, and ignition with respect to 50 lithium secondary batteries of Examples , Reference Examples, and Comparative Examples.

Since the battery of the comparative example did not have a core, it was difficult to support the wound group, and a short circuit occurred in all the lithium secondary batteries during the vibration test, resulting in smoke or ignition. On the other hand, in the lithium secondary battery 20 of the reference example 1, the warp of the core 4 was large, and a significant twist was generated, and the winding could not be performed. This is probably because the core tension was too small. In the lithium secondary battery 20 of Reference Example 2, a whirling occurred, and as a result, a short circuit occurred in 28% during the vibration test, and 12% (8% + 4%) smoked or ignited. On the other hand, in the lithium secondary batteries 20 of Examples 3 to 6, no abnormality was found at the end of the vibration test.

From the results of Comparative Example , Reference Example 2 and Examples 3 to 6, it was revealed that the twisting deviation was suppressed by applying the core tension. However, in the lithium secondary battery 20 of Reference Example 2, there was a misalignment due to the small core tension. On the other hand, in the lithium secondary batteries 20 of Examples 3 to 6, no cracking occurred. Therefore, by setting the core tension to 30 N or more, that is, the total tension (8 + 8 + 5 + 5 = 26 N) applied to the positive electrode plate, the negative electrode plate, and the separator, respectively, It has been clarified that a highly earthquake-resistant lithium secondary battery 20 that is not easily damaged can be manufactured. Further, it was found that even if the core 4 is made thin, an appropriate flat wound group can be obtained, and the volume efficiency of the lithium secondary battery 20 can be improved.

(Action etc.)
Next, the operation and the like of the lithium secondary battery 20 of the present embodiment will be described.

  In the lithium secondary battery 20 of this embodiment, the winding is applied while applying tension in the winding axis direction T to the core 4 while applying tension to the positive and negative electrode plates and the separator when the winding group 1 is wound. . For this reason, deformation of the core 4 is suppressed during winding, and an appropriate flat wound group 1 can be obtained even if the core 4 is thinned. As a result, the volume efficiency of the lithium secondary battery 20 can be improved.

  Moreover, in the lithium secondary battery 20 of this embodiment, the magnitude | size of the tension | tensile_strength of the winding axis direction T hung on the core 4 is set more than the sum total of the tension | tensile_strength each applied to a positive / negative electrode plate and a separator. Since the deviation of the positive and negative electrode plates and the separator with respect to the core is suppressed, the earthquake resistance can be improved (see Examples 3 to 6).

  Furthermore, in the lithium secondary battery 20 of this embodiment, a nonconductor is used for the core 4. For this reason, even if both ends of the winding core 4 in the winding axis direction are bonded and fixed to the battery lid 10 and the positive current collector plate (not shown), a short circuit can be prevented. Therefore, since the upper part and the lower part of the core 4 are fixed in the battery can 11, the winding group 1 can be supported by the core 4, and even if vibration is applied, the winding group 1 is misaligned or damaged. Is suppressed. As a result, the earthquake resistance of the lithium secondary battery 20 can be further improved.

  Furthermore, in the lithium secondary battery 20 of the present embodiment, the opening 5 as the attached portion is formed at both ends of the winding core 4 in the winding axis direction. For this reason, by inserting the pin 7 into the opening 5 of the winding core 4 and the opening of the jig 6 of the winding device, the winding core 4 can be easily and reliably attached to the winding device. Thereby, when the tension | tensile_strength of the winding axis direction T is applied to the winding core 4, tension | tensile_strength can be applied substantially equally, without removing the winding core 4 from a winding apparatus. Therefore, even if a thin plate-shaped core 4 is used, the core 4 is not deformed such as warping, and it is suitable for the positive and negative plates and the separator so that the winding group 1 does not bend even when vibration is applied. Tension can be applied. As a result, the earthquake resistance of the lithium secondary battery 20 can be improved.

  In addition, in this embodiment, although the circular opening 5 was shown as a to-be-attached part in the winding-axis direction both ends of the winding core 4, the present invention is not limited to this. . In the present invention, it is only necessary that the mounted portion formed on the core 4 and the mounting portion provided in the winding device can be brought into contact with each other. For example, as shown in FIG. 4, grooves 8 may be formed at both ends of the winding core 4 in the winding axis direction instead of the opening 5. In this case, the protrusion 9 is formed on the jig 6 of the winding device. The core 4 can be attached to the winding device by fitting the protrusion 9 and the groove 8 together.

  Moreover, in this embodiment, although the plate-shaped nonconductor made from a polypropylene with a thickness of 2 mm was illustrated as the core 4, the present invention is not limited to this. The core 4 is preferably a nonconductor that is resistant to a non-aqueous electrolyte and does not short-circuit the positive electrode and the negative electrode. Examples of such materials include fiber reinforced plastic (FRP), polyetheretherketone (PEEK), polyethylene, and the like. In consideration of weight reduction and volumetric efficiency improvement of the lithium secondary battery 20, it is desirable to use a lightweight and as thin core as possible.

  Furthermore, in this embodiment, although an example of the tension | tensile_strength applied to a positive electrode plate, a negative electrode plate, and a separator and the tension | tensile_strength applied to the core 4 was shown, this invention is not limited to this. It is desirable that the tension applied to the positive electrode plate, the negative electrode plate, and the separator is an appropriate tension that can suppress the occurrence of scratching in consideration of breakage of the positive and negative electrode plates and the separator. In consideration of breakage of the core 4, the tension applied in the winding axis direction T of the core 4 should be an appropriate tension that is greater than or equal to the total tension applied to the positive electrode plate, the negative electrode plate, and the separator. desirable.

  Furthermore, in the present embodiment, lithium manganate is exemplified as the positive electrode active material, but the present invention is not limited to this, and any lithium-containing complex oxide may be used. Examples of the positive electrode active material that can be used other than in the present embodiment include lithium cobaltate and lithium nickelate, and manganese and lithium in the crystal as other elements such as Fe, Co, and Ni. Lithium-containing double oxides having different compositions substituted or doped with elements such as Cr, Al, Mg, etc. may be used. The crystal structure is not particularly limited, and may have any crystal structure of spinel type, layered type, and olivine type. In the present embodiment, an amorphous carbon material is exemplified as the negative electrode active material, but the present invention is not limited to this, and any material may be used as long as it is used for a lithium secondary battery. As a negative electrode active material that can be used other than the present embodiment, for example, a graphite-based carbon material such as natural graphite, artificial graphite, or vapor-grown carbon fiber can be used. Moreover, there is no restriction | limiting in particular also about a non-aqueous electrolyte, a electrically conductive material, a binder, etc. Of course, you may use the material normally used for a lithium secondary battery.

  Furthermore, in the present embodiment, a relatively large lithium secondary battery 20 used for a power source for an electric vehicle or the like is illustrated. However, the present invention is a winding in which the positive and negative electrode plates are wound in a flat shape via a separator. Any secondary battery can be used. For example, the present invention can be applied to a nickel metal hydride battery, a nickel cadmium battery, and the like, and is not limited to the type, battery capacity, size, shape, or the like of the battery. Furthermore, the structure of the battery to which the present invention can be applied may be other than a battery having a structure in which the battery lid 10 also serves as a negative electrode terminal and the battery can 11 serves as a positive electrode terminal. As an example of such a structure, for example, a battery structure in which the battery lid 10 also serves as a positive electrode terminal and the battery can 11 serves as a negative electrode terminal can be given.

  INDUSTRIAL APPLICABILITY The present invention contributes to the manufacture and sale of wound secondary batteries in order to provide a wound secondary battery that can improve volumetric efficiency and earthquake resistance, and its manufacturing method. Have sex.

It is sectional drawing of the flat lithium secondary battery of embodiment to which this invention is applied. It is a perspective view of the winding group of the flat lithium secondary battery of embodiment. It is sectional drawing which shows typically the mounting state of the core with respect to the jig | tool of the winding apparatus when producing the winding group of a flat lithium secondary battery. It is sectional drawing which shows typically another aspect of the mounting state of the core with respect to the jig | tool of the winding apparatus when producing the winding group of a flat lithium secondary battery.

Explanation of symbols

1 winding group 4 core 5 opening (attached part)
10 Battery cover (part of battery container)
11 Battery can (part of battery container)
12 Upper lid (part of the battery case)
20 Flat lithium secondary battery (winding type secondary battery)

Claims (4)

The positive electrode plate, with tension to the negative electrode plate and a separator, and the said positive electrode plate to the winding core under tension in the winding axis direction to the winding core of the non-conductive plate-shaped negative electrode plate via the separator A wound group wound in a flat shape;
An electrolyte solution infiltrating the wound group;
A battery container containing the wound group and the electrolyte;
Equipped with a,
The wound secondary battery according to claim 1, wherein the tension applied to the core is equal to or greater than the total tension applied to the positive and negative electrode plates and the separator .   The wound secondary battery according to claim 1, wherein the winding core has a mounted portion for mounting on a winding device at both ends in the winding axis direction. A method for manufacturing a wound secondary battery according to claim 1 or 2 ,
A mounting step of mounting a non-conductive core in the form of a plate on the winding device;
While applying tension to each of the positive and negative electrode plates and the separator, and winding the positive electrode plate and the negative electrode plate in a flat shape through the separator while applying tension in the winding axis direction to the core. Winding step,
Only including,
In the winding step, the magnitude of the tension applied to the core is equal to or greater than the total tension applied to the positive and negative electrode plates and the separator . In the mounting step, to claim 3, characterized in that the mating attachment section which is formed in the winding axis direction end portion of the winding core, are brought into contact with a mounting portion provided on the wound device mounted The manufacturing method as described.

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