JP2007123009A - Wound type battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wound type battery having a high capacity by improving its volume energy density. <P>SOLUTION: The wound type battery has a positive electrode 1 and a negative electrode 4, in which electrode active material is formed on a current collector of belt shape, laminated and wound through a separator 7 and housed in an outer package. The separator 7 is not arranged at the portion where the electrodes of same polarity or the electrode and the outer package to become same polarity are opposed, and the separator 7 is arranged at the portion where the positive electrode 1 and the negative electrode 4 are opposed to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a wound battery in which a positive electrode and a negative electrode are laminated via a separator and wound to improve the volume energy density of the wound battery stored in an exterior body.

  Various types of batteries are used as power sources for small electronic devices, and small and large-capacity batteries are used as power sources for mobile phones and notebook personal computers. A battery using a non-aqueous electrolyte is used.

  Recently, there has been a strong demand for improvement in high-rate discharge characteristics as well as improvement in battery energy density. In a wound battery, the surface area of the positive electrode and the negative electrode is increased to increase the volumetric energy density and high capacity of the battery. The rate discharge characteristics are improved. In addition, since a battery using a rectangular battery or a laminate outer package can be efficiently mounted on a device such as a mobile phone or a notebook personal computer, a battery having a large energy density and a small thickness is used in such applications. There is a strong demand.

  In general, a wound battery using a prismatic battery or a laminated outer package contains a flat wound electrode body rather than a perfect circle.

  As a conventional wound-type battery, a structure in which a flat wound electrode body is housed in the battery exterior body, a structure in which the electrode plates of the same polarity located on the innermost side face each other with two separators proposed (For example, refer to Patent Document 1).

  However, since the two separators between the same-polarity electrode plates are not necessary for insulation, an extra separator portion exists.

  Further, in a prismatic battery in which a power generation element having a winding structure in which strip-like positive and negative electrode plates are wound via a separator is housed in a prismatic container, both surfaces of one polarity electrode plate at the winding core and The end of the longitudinal direction is covered with a separator, and the electrode plate of the other polarity is located in the inner portion between the end of one electrode plate and the first bent portion, in the vicinity of the first bent portion. And the other electrode plate is wound at the tip of one electrode plate and then wound around the separator so as to face the one electrode plate. A structure has been proposed in which electrode plates having different polarities face each other on the entire surface (see, for example, Patent Document 2).

  In this case, it is said that a battery excellent in volume efficiency and weight efficiency having a winding structure in which the same polarity electrode plates do not face each other is provided. However, in this structure, since the separator has a structure covering the outer periphery and has the same polarity as the exterior body, there is an extra separator portion.

  Further, in a wound battery in which a positive electrode having an electrode active material formed on a strip-shaped current collector and a negative electrode are laminated via a separator, the positive electrode is provided around the entire circumference of the winding core. A structure has been proposed in which a single-side coated portion of an active material is provided and the surface of the winding core portion on which the positive electrode active material is not applied faces the inner side of the wound body (for example, Patent Document 3). reference).

  According to the drawing of Patent Document 3, the separator has a structure in which two separators are arranged in a portion where the same polar plate faces in the core portion of the wound battery, and there is an extra separator portion.

JP 2004-349141 A JP-A-9-213374 JP 2002-8709 A

  An object of the present invention is to provide a wound battery that has a high volumetric energy density and can be manufactured at low cost.

  The wound battery of the present invention for solving the above-described problem is a laminate of a positive electrode and a negative electrode each having an electrode active material formed on a strip-shaped current collector with a separator interposed therebetween, and is housed in an outer package. In the wound battery, the separator is not disposed in the portion where the electrodes having the same polarity, or the electrode having the same polarity and the exterior body face each other, and the separator is disposed in the portion where the positive electrode and the negative electrode face each other. Features.

  According to the wound battery of the present invention, it is possible to reduce the amount of separator used by reducing the number of separators disposed between the electrodes of the same polarity, and to further improve the volume energy density and the reduced thickness of the separator. .

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram for explaining the positional relationship between a positive electrode, a negative electrode, and a separator of a flat wound electrode body according to a first embodiment of the wound battery of the present invention. The tip part of the negative electrode current collector 5 is provided with a portion where the negative electrode active material 6 is not applied on both surfaces up to the first bent part, and the negative electrode current collector 5 is connected to the negative electrode current collector 5 so as to be inside, A single-side coated portion where the negative electrode active material 6 is not coated is provided for one round after the first bent portion. The positive electrode 1 has a structure in which a positive electrode active material 3 is applied to both surfaces from the front end portion of the positive electrode current collector 2, and a separator 7 is disposed so as to wrap the positive electrode 1 from the front end portion of the positive electrode 1. The winding starts so as to face the single-sided application start part of the negative electrode active material 6 on the inner side, and the outer side faces the double-sided application start part. For this reason, the separator 7 is not disposed in the portion where the negative electrode 4 in the winding center overlaps.

  The terminal portion of the negative electrode 4 has a structure in which the negative electrode active material 6 is applied to both surfaces of the negative electrode current collector 5, and the positive electrode 1 is provided with a single-side coating portion for one turn at the terminal portion via the separator 7. It arrange | positions between the single-sided application start part and the single-sided application end part. Further, the positive electrode conductive tabs 8 are connected to the inner surfaces of the terminal portions of the positive electrode 1 where the positive electrode active material 3 is not applied. The end of the separator 7 is disposed so as to enclose the negative electrode 4. The positive electrode conductive tabs 8 are connected to the portions where the positive electrode active material 3 is not applied on both surfaces of the terminal portion of the positive electrode 1 so as to be inside. In the case of using a battery can made of an aluminum alloy whose outer casing is a positive electrode, the outermost peripheral portion of the wound electrode body is the positive electrode 1, so that the separator 7 for insulating the outer periphery is not disposed.

  FIG. 2 is a diagram for explaining the positional relationship between the positive electrode, the negative electrode, and the separator of the flat wound electrode body according to the second embodiment of the wound battery of the present invention. The tip of the negative electrode current collector 5 is connected to the portion where the negative electrode active material 6 is not applied on both sides so that the negative electrode conductive tab 9 is on the inside, and the negative electrode active material 6 is connected to the inside from the front of the first bent portion. A single-side application part that is not applied is provided for one round. The positive electrode 1 has a structure in which the positive electrode active material 3 is applied to both surfaces from the front end portion of the positive electrode current collector 2, and a separator 7 is disposed so as to wrap the positive electrode 1 from the front end portion of the positive electrode 1. Winding is started so as to face the single-sided coating start part of the negative electrode active material 6 on the inner side, and the outer side is arranged to face the double-sided coating start part. For this reason, the separator 7 is not disposed in the portion where the negative electrode 4 in the winding center overlaps.

  The terminal part of the negative electrode 4 has a structure in which the negative electrode active material 6 is applied to both surfaces of the negative electrode current collector 5, and a positive electrode in which a single-sided application part for one round is provided on the terminal part inside through the separator 7. It arrange | positions so that the single-sided application | coating start part of 1 may face the single-sided application end part on the outer side. The positive electrode conductive tabs 8 are connected to the portions where the positive electrode active material 3 is not applied on both surfaces of the terminal portion of the positive electrode 1 so as to be inside. When the outer package is a positive electrode, the outermost peripheral portion of the wound electrode body is the positive electrode 1, so that the separator 7 for insulating the outer periphery is not necessary.

  FIG. 3 is a diagram for explaining the positional relationship between the positive electrode, the negative electrode 4 and the separator of the flat wound electrode body according to the third embodiment of the wound battery of the present invention. After the first bent portion of the negative electrode 4 in which the negative electrode active material 6 is applied to both surfaces of the negative electrode current collector 5, the positive electrode active material 3 is formed on both surfaces of the positive electrode current collector 2 wrapped with the separator 7 outside the negative electrode 4. It has a structure in which the tip of the positive electrode 1 coated with is disposed and wound. For this reason, the separator 7 is not disposed in the portion where the negative electrode 4 in the winding center overlaps.

  Further, for all the embodiments, when there is a non-coated portion of the positive electrode active material 3 at the tip of the positive electrode 1 at the center of the flat wound electrode body, the negative electrode at the end of the negative electrode 4 at the outer periphery Even in the case where the active material 6 is provided, a separator is not disposed in a portion where the electrodes having the same polarity or between the electrodes having the same polarity and the outer casing are opposed to each other, and a separator is disposed in a portion where the positive electrode and the negative electrode are opposed. Thus, an equivalent effect can be obtained. The negative electrode 4 facing the positive electrode 1 is disposed so that the portion where the negative electrode active material 6 is applied covers the portion where the positive electrode active material 3 is applied. A portion to which the negative electrode active material 6 is applied is always present on the surface. By arranging in this way, in a lithium ion secondary battery, lithium metal can be prevented from depositing on the negative electrode during charging, and the safety of the battery can be improved.

Hereinafter, the case where the wound battery of the present invention is a lithium ion battery will be described in detail. A composite aluminum oxide, such as Li _x CoO ₂ , Li _x MO ₂ (wherein M represents at least one transition metal) as a positive electrode active material 3, is applied to a strip-shaped aluminum foil that serves as a positive electrode current collector. _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x MnO ₃ , Li _x Ni _y Co _(1-y) O ₂ , etc., conductive materials such as carbon black, binders such as polyvinylidene fluoride (PVDF), etc. The positive electrode 1 is produced by applying a positive electrode coating solution prepared by dispersing and kneading a solvent such as N-methyl-2-pyrrolidone (NMP) with a coating apparatus. After the application on one side is finished, a predetermined part is applied and dried on the opposite side after drying.

  Cokes such as pyrolytic carbons, pitch coke, needle coke, petroleum coke, and the like that can be doped and dedoped with lithium as the negative electrode active material 6 on the surface of a strip-shaped copper foil or the like that becomes the negative electrode current collector 5, graphite Conductive materials such as carbon black, carbonaceous materials such as carbon fiber, activated carbon such as carbon fiber, activated carbon such as carbon fiber, activated carbon, carbon fiber, activated carbon such as activated carbon, carbon fiber, activated carbon The negative electrode 4 is obtained by applying a prepared negative electrode coating liquid prepared by dispersing and kneading a binder such as a conductive material, polyvinylidene fluoride (PVDF) and a solvent such as N-methyl-2-pyrrolidone (NMP) with a coating apparatus. Produced. After the application on one side is finished, a predetermined part is applied and dried on the opposite side after drying.

  In the positive electrode 1 and the negative electrode 4 thus obtained, after compressing each electrode to a predetermined thickness, each electrode is cut into a predetermined shape by a cutting device, and the positive electrode and the negative electrode conductive tab are joined to each other. Then, a flat wound electrode body is manufactured by winding the positive electrode 1 and the negative electrode 4 at the predetermined positions through a polyolefin separator 7 having a thickness of 20 μm in a predetermined position. The thickness of the separator 7 is preferably 8 to 25 μm. If the separator is thick, the internal resistance of the battery increases and the load characteristics deteriorate. Further, since the flat wound electrode body is thick, the volume energy density of the battery is small. Therefore, the thickness of the separator is preferably 25 μm or less. In addition, the thinner the separator, the better for improving the volume energy density of the battery, but maintaining the good mechanical strength, etc. necessary for short circuit prevention, electrolyte retention, and flat wound electrode body production. Therefore, the thickness of the separator is preferably 8 μm or more. After heating and compressing the flat wound electrode body, it is housed in an aluminum, aluminum alloy or iron-based battery can and injected with a non-aqueous electrolyte, then the external connection terminal, a safety valve that releases the pressure by increasing the internal pressure of the battery, and the battery A lithium ion battery is manufactured by attaching and sealing a lid provided with a PTC element or the like that cuts off the current by increasing the electrical resistance due to an increase in temperature. Alternatively, the wound electrode body is housed in a laminate outer body to manufacture a lithium ion battery.

  Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

  The winding type battery of the present invention will be described with reference to FIG. 1 described as the first embodiment. As the negative electrode 4, 20 mm from the tip of the negative electrode current collector 5 made of copper foil having a length of 453 mm, a width of 44 mm, and a thickness of 0.010 mm is set as a non-applied part, and adjacent to it, one turn of the winding core part. A single-side coated portion was formed at 56 mm corresponding to the length, and the negative electrode conductive tab 9 was joined to the non-coated portion. The negative electrode active material 6 is compressed after a negative electrode coating solution containing a carbonaceous material that can be doped and dedoped with lithium is applied and dried with a coating apparatus.

  The positive electrode 1 has a length of 476 mm, a width of 43 mm, and a thickness of 0.015 mm from the terminal end of the positive electrode current collector 2 made of aluminum foil, 38 mm as a non-applied portion, and a length corresponding to one circumference of the outer peripheral portion adjacent thereto. A single-side coated portion was formed at 64 mm corresponding to the thickness, and the positive electrode conductive tab 8 was joined to the non-coated portion. The positive electrode active material 3 is compressed after applying and drying a positive electrode coating solution containing lithium cobaltate with a coating apparatus.

  Next, winding is started so that the negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 of the negative electrode 4 is inside, and the positive electrode is started from the tip of the single-side coated portion after the first bent portion. The positive electrode 1 is placed so as to be wrapped with a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm so that the tip of the coating portion of the positive electrode active material 3 is positioned 2 to 4 mm later. The electrode 4 was cut by extending 2 to 10 mm from the terminal portion, and was disposed so as to enclose the negative electrode 4, and the single-sided positive electrode 1 was disposed so as to face the outermost negative electrode. Thereafter, it was compression molded and housed in a battery can made of aluminum, and an electrolytic solution was injected to produce a wound battery.

(Comparative Example 1)
FIG. 4 is a diagram for explaining the positional relationship between a positive electrode, a negative electrode, and a separator of a flat wound electrode body according to Comparative Example 1 of a conventional wound battery. The negative electrode 4 and the positive electrode 1 have the same structure as in the first embodiment. From the tip of the negative electrode 4, it is disposed so as to be wrapped with a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm, and the negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 is wound inside. The positive electrode 1 is wound so that the tip of the coating portion of the positive electrode active material 3 of the positive electrode 1 is positioned 2 to 4 mm after the tip of the single-side coating portion after the first bending portion, and the separator 7 was cut by extending 2 to 10 mm from the terminal portion of the negative electrode 4 and disposed so as to wrap the negative electrode 4, and the single-sided positive electrode 1 was disposed so as to face the outermost negative electrode. Thereafter, it was compression molded and housed in a battery can made of aluminum, and an electrolyte was injected to produce a wound battery.

  In Comparative Example 1, two separators 7 are overlapped with each other at the portion where the negative electrodes 4 face each other and do not contribute to insulation, and four sheets are extra in thickness. In the first embodiment, the separator 7 is disposed so as to wrap the positive electrode 1, so that it is possible to reduce the thickness of the separator 7 for four sheets in an extra thickness compared to the first comparative example.

(Comparative Example 2)
FIG. 5 is a diagram for explaining the positional relationship between the positive electrode, the negative electrode, and the separator of a flat wound electrode body according to Comparative Example 2 of a conventional wound battery (the tip of the separator 7 is the tip of the negative electrode 4). The same as Comparative Example 1 except that it is installed earlier and winding is started from the separator 7). The negative electrode 4 and the positive electrode 1 have the same structure as in the first embodiment. The negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 of the negative electrode 4 is installed so as to be inside, and the positive electrode active material of the positive electrode 1 from the tip of the single-side coated portion after the first bent portion. The positive electrode 1 is disposed so as to be sandwiched between polyolefin separators 7 having a thickness of 20 μm and a width of 46 mm so that the tip of the three application portions is positioned 2 to 4 mm later. The tip end of the separator 7 is placed before the tip end of the negative electrode 4 and winding starts from the separator 7. The separator 7 was cut by extending 2 to 10 mm from the terminal portion of the negative electrode 4 and arranged so as to wrap the negative electrode 4, and the single-sided positive electrode 1 was arranged so as to face the outermost negative electrode. Then, it compression-molded, accommodated in the battery can which consists of aluminum, and injected electrolyte solution.

  This Comparative Example 2 referred to Patent Document 3. Although there is no detailed description in Patent Document 3, a drawing of a wound electrode body is described. The structure of this wound body has a structure in which the negative electrode 4 is an outer periphery and the positive electrode 1 is an inner periphery. The inner peripheral separator 7 is disposed so as to enclose the negative electrode 4, but the front end of the separator 7 is longer than the front end of the negative electrode 4 by a half turn to the inner peripheral side. Two separators 7 overlap each other at the portion where the same poles face each other and do not contribute to insulation, and the separators 7 for two sheets are extra in thickness. In Patent Document 3, the negative electrode is the outer periphery and the positive electrode is the inner periphery. However, since the negative electrode can be the inner periphery and the positive electrode can be the outer periphery, this structure is referred to as Comparative Example 2. In the first embodiment, the separators 7 for two sheets are reduced in thickness by one turn compared to the second comparative example.

  The winding type battery of the present invention will be described with reference to FIG. 2 described as the second embodiment. As the negative electrode 4, 12 mm from the tip of the negative electrode current collector 5 made of copper foil having a length of 445 mm, a width of 44 mm, and a thickness of 0.010 mm is set as an uncoated portion, and adjacent to it, one turn of the winding core portion. A single-side coated portion was formed at 56 mm corresponding to the length, and the negative electrode conductive tab 9 was joined to the non-coated portion. The negative electrode active material 6 is compressed after a negative electrode coating solution containing a carbonaceous material that can be doped and dedoped with lithium is applied and dried with a coating apparatus.

  As the positive electrode 1, 46 mm from the terminal portion of the positive electrode current collector 2 made of an aluminum foil having a length of 480 mm, a width of 43 mm, and a thickness of 0.015 mm is set as a non-applied portion, and the length corresponding to one circumference of the outer peripheral portion is adjacent thereto. A single-side coated portion was formed at 68 mm corresponding to the thickness, and the positive electrode conductive tab 8 was joined to the non-coated portion. The positive electrode active material 3 is compressed after applying and drying a positive electrode coating solution containing lithium cobaltate with a coating apparatus.

  Next, winding is started so that the negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 of the negative electrode 4 is inside, and the positive electrode is started from the tip of the single-side coated portion before the first bent portion. The positive electrode 1 is placed and wrapped so as to be wrapped by a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm so that the front end of 1 is positioned 2 to 4 mm later. It cut | disconnected by extending 10 mm, it has arrange | positioned so that the negative electrode 4 may be wrapped, and the single-sided coating positive electrode 1 was arrange | positioned so as to oppose the negative electrode of the outermost periphery. Unlike Example 1, Example 2 shows a case where the tip of the active material application part is on the same surface as the tip of the negative electrode plate. Thereafter, it was compression molded and housed in a battery can made of aluminum, and an electrolyte was injected to produce a wound battery.

(Comparative Example 3)
FIG. 6 is a diagram for explaining the positional relationship between a positive electrode, a negative electrode, and a separator of a flat wound electrode body according to Comparative Example 3 of a conventional wound battery. The negative electrode 4 and the positive electrode 1 have the same structure as in Example 2. The negative electrode 4 is disposed so as to be wrapped with a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm from the tip of the negative electrode 4, and the negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 is placed inside. Winding is started, and the positive electrode 1 is wound so that the front end of the positive electrode 1 is positioned 2 to 4 mm after the front end of the single-side coated part before the first bent part. It cut | disconnected by extending 2-10 mm from the termination | terminus part, it has arrange | positioned so that the negative electrode 4 may be wrapped, and the positive electrode of single-sided application | coating was arrange | positioned at the outermost periphery. Thereafter, it was compression molded and housed in a battery can made of aluminum, and an electrolyte was injected to produce a wound battery. Two separators 7 are overlapped by 3/4 rounds at the central part of the flat wound electrode body so that the negative electrodes face each other and do not contribute to insulation, and four or two separators 7 are added in thickness. It has become. Since the separator 7 is disposed so as to wrap the positive electrode 1 in the second embodiment, the separator 7 for four or two sheets can be reduced in thickness by an extra 3/4 round compared to the third comparative example. .

  A description will be given with reference to FIG. 3 described as the third embodiment of the wound battery of the present invention. As the negative electrode 4, 20 mm from the terminal portion of the negative electrode current collector 5 made of copper foil having a length of 453 mm, a width of 44 mm, and a thickness of 0.010 mm was used as an uncoated portion, and the negative electrode conductive tab 9 was joined to the non-coated portion. The negative electrode active material 6 is compressed after a negative electrode coating solution containing a carbonaceous material that can be doped and dedoped with lithium is applied and dried with a coating apparatus.

  The positive electrode 1 has a length of 472 mm, a width of 43 mm, and a thickness of 0.015 mm as a non-applied portion of 38 mm from the end portion of the positive electrode current collector 2 made of an aluminum foil. A single-side coated part was formed at 64 mm corresponding to the thickness, and a positive electrode conductive tab was joined to the non-coated part. The positive electrode active material 3 is compressed after applying and drying a positive electrode coating solution containing lithium cobaltate with a coating apparatus.

  Next, winding is started so that the negative electrode conductive tab 9 connected to the non-coated portion of the negative electrode active material 6 of the negative electrode 4 is inside, and the positive electrode is started from the tip of the single-side coated portion after the first bent portion. The positive electrode 1 is placed so as to be wrapped with a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm so that the tip of the coating portion of the positive electrode active material 3 is positioned 2 to 4 mm later. The electrode 4 was cut by extending 2 to 10 mm from the terminal portion, and was disposed so as to enclose the negative electrode 4, and the single-sided positive electrode 1 was disposed so as to face the outermost negative electrode. Thereafter, it was compression molded and housed in a battery can made of aluminum, and an electrolyte was injected to produce a wound battery.

(Comparative Example 4)
FIG. 7 is a diagram for explaining the positional relationship between the positive electrode, the negative electrode 4 and the separator of a flat wound electrode body according to Comparative Example 4 of a conventional wound battery. The negative electrode 4 and the positive electrode 1 have the same structure as that of Example 3. The negative electrode 4 is arranged so as to be wrapped with a polyolefin separator 7 having a thickness of 20 μm and a width of 46 mm from the tip of the negative electrode 4, and the positive electrode 1 is arranged outside the negative electrode 4 after the first bent part. Wind. Thereafter, the end portion was produced in the same manner as in Example 3 to produce a wound battery. This Comparative Example 4 referred to Patent Document 1. In Patent Document 1, there is a description about the center portion of the flat wound electrode body, but the non-coated portion, single-side coated portion, and conductive tab of the electrode active material are not clearly shown, but the wound electrode body as shown in FIG. Can be estimated. The feature is that the electrode plates with the same polarity located on the innermost side face each other with two separators 7 interposed therebetween.

  In this structure, two separators 7 are overlapped in a portion where the same poles face each other and do not contribute to insulation, and four separators 7 are extra in thickness. In Example 3, four separators 7 are reduced in thickness by one turn compared to Comparative Example 4. The structure of the central part of the wound electrode body of Example 3 is the same as that of Example 1.

  For these examples and comparative examples, the comparison of the amount of separator used for each of the five average values is shown in Table 1, and the battery capacity comparison in which the amount of separator reduction is converted to an increase in battery capacity is summarized in Table 2. The battery capacity is measured by charging at a constant current of 1000 mA with a constant voltage and constant current charging method at 20 ° C., and when the voltage reaches 4.2 V, switching to 4.2 V constant voltage charging is performed. Is 2.5 hours in total. Discharge was measured by discharging at 20 ° C. with a constant current of 200 mA until the voltage reached 3.0V.

  Since the structure according to the present invention can provide a sufficient effect as long as the battery includes a flat wound electrode body regardless of a non-aqueous battery such as a lithium ion battery, the use thereof may be a primary battery or a secondary battery. Absent. Although the lithium ion battery was produced in the said Example, it can utilize for an alkaline storage battery, a lithium primary battery, etc. Moreover, as a specific example of the battery exterior body that accommodates the flat wound electrode body, a laminate exterior body and the like can be exemplified in addition to the square exterior cans used in the above-described embodiments.

The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by 1st embodiment of this invention, the negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by 2nd embodiment of this invention, and the negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by 3rd embodiment of this invention, and the negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by the comparative example 1 of the conventional winding type battery, a negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by the comparative example 2 of the conventional winding type battery, a negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by the comparative example 3 of the conventional winding type battery, a negative electrode, and a separator. The figure explaining the positional relationship of the positive electrode of the flat winding electrode body by the comparative example 4 of the conventional winding type battery, a negative electrode, and a separator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Positive electrode collector 3 Positive electrode active material 4 Negative electrode 5 Negative electrode current collector 6 Negative electrode active material 7 Separator 8 Positive electrode conductive tab 9 Negative electrode conductive tab

Claims (4)

  In a wound battery in which a positive electrode and a negative electrode formed with an electrode active material on a strip-shaped current collector are stacked and wound via a separator, and housed in an exterior body, A separator is not disposed in a portion where the electrode and the outer package face each other, and a separator is disposed in a portion where the positive electrode and the negative electrode face each other.   At the winding center for starting winding of the wound battery stored in the exterior body, the positive electrode and the negative electrode on which the electrode active material is formed on the belt-shaped current collector are laminated and wound via the separator. The wound battery according to claim 1, wherein the negative electrodes face each other.   At the winding center for starting winding of the wound battery stored in the exterior body, the positive electrode and the negative electrode on which the electrode active material is formed on the belt-shaped current collector are laminated and wound via the separator. The wound battery according to claim 1, wherein the positive electrodes face each other.   The wound type battery according to any one of claims 1 to 3, wherein the outer package is an aluminum, aluminum alloy, iron-based battery can, or a laminate outer package.

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