JLab/Cambridge, Exh. 1039, p. 1
`JLab/Cambridge v. Varta, 2020-01212
`
`

`

`(19) Japanese Patent Office (JP)
`
`(12) Publication of Unexamined
`Patent Application (A)
`
`(51) Int. Cl.7
`H01M 10/40
`
`
`4/78
`
`ID Number
`
`
`
`
`
`
`
`
`
`FI
`H01M
`
`
`(11) Patent Application Disclosure
`2003-31266
`(P2003-31266A)
`(43) Publication Date: January 31, 2003
`
`Theme code (ref.)
`10/40
`5H017
`4/78
`5H029
`
`Z
`A
`
`Request for Examination: Not Requested Number of Claims: 1 OL (Total pages: 7)
`
`(21) Application No.: 2001-215825 (P2001-215825)
`
`(22) Application Date: July 16, 2001
`
`(71) Applicant
`
`
`
`
`
`(72) Inventor
`
`
`
`
`
`(72) Inventor
`
`
`
`
`
`(74) Agent
`
`
`
`000003539
`Toshiba Battery Co. Ltd.
`3-4-10 Minamishinagawa, Shinagawa-ku,
`Tokyo
`KANNOU, Kouji
`c/o Toshiba Battery Co. Ltd.
`3-4-10 Minamishinagawa, Shinagawa-ku,
`Tokyo
`FUJITA, Kouji
`c/o Toshiba Battery Co. Ltd.
`3-4-10 Minamishinagawa, Shinagawa-ku,
`Tokyo
`100058479
`Patent Agent SUZUE, Masahiko (and 6
`others)
`
`
`
`
`
`
`
`
`
`(54) [Title of the Invention] FLAT-TYPE NON-
`AQUEOUS SECONDARY BATTERY
`(57) [Abstract]
`[Purpose] The purpose is to provide a flat-type non-
`aqueous secondary battery with
`improved discharge
`capacity.
`[Resolution Means] A flat-type non-aqueous secondary
`battery having a sealed container obtained by crimping and
`fixing a positive electrode container 1 and a negative
`electrode container 2 through an insulating gasket 3, and an
`electrode group 4 which is stored in the sealed container and
`is composed of a spirally rolled laminated member having
`a positive electrode including a positive electrode current
`collector and a negative electrode including a negative
`electrode current collector, wherein an end part of the
`positive electrode current collector or the negative electrode
`current collector is made to protrude from one of the roll
`surfaces electrode group, and the protruding end part is bent
`to contact the inner surface of the positive electrode
`container or the negative electrode container having the
`same electrode as the protruding end part.
`
`Continued on last page
`
`
`
`JLab/Cambridge, Exh. 1039, p. 2
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`
`

`

`[Scope of Patent Claims]
`What Is Claimed Is:
`[Claim 1] A flat-type non-aqueous secondary battery having a
`sealed container obtained by crimping and fixing a positive
`electrode container and a negative electrode container through an
`insulating gasket, and an electrode group which is stored in the
`sealed container and is composed of a spirally rolled laminated
`member having a positive electrode including a positive electrode
`current collector and a negative electrode including a negative
`electrode current collector;
`wherein an end part of the positive electrode current collector or
`the negative electrode current collector is made to protrude from
`one of the roll surfaces electrode group, and the protruding end part
`is bent to contact the inner surface of the positive electrode
`container or the negative electrode container having the same
`electrode as the protruding end part.
`[Detailed Description of the Invention]
`[0001]
`[Technical Field of the Invention] The present invention relates to
`a flat-type non-aqueous secondary battery.
`[0002]
`[Background Technology] The main application of small non-
`aqueous electrolyte batteries such as coin or button type non-
`aqueous electrolyte batteries has been as a main power source for
`small devices and a backup power source for recording elements.
`All cases consume very little power and are intended for long-term
`use. The structure is known to include a metal positive electrode
`case containing a pellet-shaped positive electrode and a metal
`negative electrode case containing a pellet-shaped negative
`electrode, with a separator interposed between the positive and
`negative electrodes. With this structure, the reactivity is low due to
`the small reaction area between the positive and negative
`electrodes, and only a small current can be discharged.
`[0003] On the other hand, cylindrical and rectangular batteries
`used in mobile phones and electronic devices are capable of
`discharging at high currents because they use a group of electrodes
`rolled in a spiral shape with a separator interposed between the
`band-shaped positive and negative electrodes. In addition, there is
`a degree of freedom in designing the thickness and area of the
`electrode to match the load and capacity of the required electronic
`device.
`[0004] Incidentally, there is a need for coin- or button-type non-
`aqueous electrolyte batteries to carry a large current due to the
`diversification of their uses. In order to carry a large current, the
`reaction area of the electrodes must be large, and a rolled structure
`is required, like a cylindrical or square battery. There is a method
`of storing thin, square electrodes by crushing rolled structure
`electrodes in a flat container used for coin or button type batteries
`(e.g., Japanese Unexamined Patent Application 2000-164259), but
`storing a square electrode group in a cylindrical container causes a
`problem in that a lot of space is wasted. However, storing a square
`electrode group in a cylindrical container causes a problem in that
`a lot of wasted space is generated.
`[0005] In order to solve such a problem, Japanese Unexamined
`Patent Application H11-345626 proposes making the height in the
`direction of the central axis of the roll smaller than the size in the
`direction perpendicular to the central axis.
`[0006] However, in the battery described in Japanese Unexamined
`Patent Application H11-345626, high discharge capacity cannot be
`obtained because the electrical connection is made by contact
`between the tab and the container.
`
`(2) 2003-31266 (P2003-31266A)
`
`[0007]
`[Problem to be Solved by the Invention] An object of the present
`invention is to provide a flat-type non-aqueous secondary battery
`with improved discharge capacity.
`[0008]
`[Means for Solving the Problem] The flat-type non-aqueous
`secondary battery of the present invention has a sealed container
`obtained by crimping and fixing a positive electrode container and
`a negative electrode container through an insulating gasket, and an
`electrode group which is stored in the sealed container and is
`composed of a spirally rolled laminated member having a positive
`electrode including a positive electrode current collector and a
`negative electrode including a negative electrode current collector,
`wherein an end part of the positive electrode current collector or
`the negative electrode current collector is made to protrude from
`one of the roll surfaces electrode group, and the protruding end part
`is bent to contact the inner surface of the positive electrode
`container or the negative electrode container having the same
`electrode as the protruding end part.
`[0009]
`[Description of the Preferred Embodiments] An example of a flat-
`type non-aqueous secondary battery is described.
`[0010] This flat-type non-aqueous secondary battery has a sealed
`container obtained by crimping and fixing a positive electrode
`container and a negative electrode container through an insulating
`gasket, and an electrode group which is stored in the sealed
`container and is composed of a spirally rolled laminated member
`having a positive electrode including a positive electrode current
`collector and a negative electrode including a negative electrode
`current collector. A separator can be provided between the positive
`and negative electrodes.
`[0011] The flat non-aqueous secondary battery can have the
`structure described in (a) to (c) below.
`[0012] (a) The end part of the positive electrode current collector
`is made to protrude from one roll surface of the electrode group,
`and the protruding end part is bent to contact the inner surface of
`the positive electrode container.
`[0013] (b) The end part of the negative electrode current collector
`is made to protrude from one roll surface of the electrode group,
`and the protruding end part is bent to contact the inner surface of
`the negative electrode container.
`[0014] (c) The end part of the positive electrode current collector
`is made to protrude from one roll surface of the electrode group,
`and the protruding end part is bent to contact the inner surface of
`the positive electrode container. Furthermore, the end part of the
`negative electrode current collector is made to protrude from a
`second roll surface of the electrode group, and the protruding end
`part is bent to contact the inner surface of the negative electrode
`container.
`[0015] Herein, the roll surface refers to the surface perpendicular
`to the roll axis of the electrode group.
`[0016] Of the aforementioned configurations (a) to (c), the
`discharge capacity of configuration (c) can be significantly
`enhanced, which is desirable.
`[0017] With the aforementioned configurations (a) to (c), the edge
`part of the negative electrode active material-containing layer
`preferably protrudes from the edge of the positive electrode active
`material-containing layer. This is because lithium dendrites tend to
`precipitate at the edge of the negative electrode active material-
`containing layer when the edge part of the negative electrode active
`material-containing layer is facing the positive electrode active
`material-containing layer.
`
`
`
`JLab/Cambridge, Exh. 1039, p. 3
`JLab/Cambridge v. Varta, 2020-01212
`
`

`

`[0018] With the aforementioned configurations (a) to (c),
`the end parts protruding from the roll surface can be bent to
`the outer or inner circumference of the electrode group.
`Bending to the inner circumference is preferred because it
`is less likely to cause an internal short circuit.
`[0019] In the electrode group, the length in the direction
`perpendicular to the roll axis is preferably longer than the
`length in the roll axis direction. Using this configuration, a
`non-aqueous electrolyte battery with a thin profile and high
`energy density can be obtained.
`[0020] The positive electrode, negative electrode, separator
`and non-aqueous electrolyte are described below.
`[0021] (1) Positive Electrode
`The positive electrode is formed from a positive electrode
`layer containing an active material and a conductive
`material, supported on a current collector.
`[0022] The active material can be various oxides (for
`example, lithium manganese complex oxides such as
`LiMn2O4, manganese dioxide, lithium nickel complex
`oxide such as LiNiO2, lithium cobalt complex oxides such
`as LiCoO2, lithium cobalt nickel complex oxide, lithium
`containing amorphous vanadium pentoxide, and the like) or
`chalcogen compounds (for example, titanium disulfide,
`molybdenum disulfide, etc.). Of these, lithium manganese
`composite oxides, lithium cobalt composite oxides and
`lithium nickel composite oxides are preferably used.
`[0023] For example, aluminum expanded metal, aluminum
`foil, aluminum mesh, aluminum punched metal, and the like
`can be used as the current collector.
`[0024] Examples of the conductive material (conductive
`filler) include carbon black (for example, acetylene black,
`furnace black, ketjen black, and the like), graphites (for
`example, artificial graphite, powdered graphite, powdered
`expanded graphite, and the like), pulverized glassy carbon,
`powdered or crushed coke, carbon fiber pulverized material,
`graphitized carbon fiber pulverized material, nickel powder,
`and the like. The aforementioned conductive materials may
`be used alone, or two or more materials may be blended and
`used together.
`[0025] The positive electrode is made, for example, by
`preparing a slurry by kneading a positive electrode active
`material, a conductive material, and a binder in the presence
`of a solvent, applying the slurry to a current collector,
`drying, and then press forming.
`for example,
`[0026] The binding agent may be,
`polyvinylidene fluoride, styrene butadiene copolymer,
`carboxymethyl cellulose, derivatives thereof, and the like.
`[0027] (2) Negative Electrode
`The negative electrode is formed from a negative electrode
`layer containing an active material supported on a current
`collector.
`[0028] The active material can be, for example, a
`carbonaceous material that absorbs and releases lithium
`
`(3) 2003-31266 (P2003-31266A)
`
`ions. Examples of the carbonaceous material include
`materials obtained by calcination of organic polymer
`compounds (for example, phenol resin, polyacrylonitrile,
`cellulose, and the like), coke, materials obtained by
`calcination of mesophase pitch, artificial graphite, natural
`graphite, and the like. Of these, a carbonaceous material
`obtained by calcinating mesophase pitch at a temperature of
`500-3000°C under normal or reduced pressure in an inert
`gas atmosphere such as argon gas or nitrogen gas is
`preferably used.
`[0029] Examples of the current collector can include copper
`expanded metal, copper foil, copper mesh, copper punched
`metal, and the like.
`[0030] The negative electrode is allowed to contain a
`conductive material (conductive filler). The conductive
`material (conductive filler) can be the same materials as
`described for the positive electrode.
`[0031] The negative electrode is made, for example, by
`preparing a slurry by kneading a negative electrode active
`material and a binder, in the presence of a solvent, applying
`the slurry to a current collector, drying, and then press
`forming.
`[0032] The binder can be the same as the aforementioned
`binder described for the positive electrode.
`[0033] (3) Separator
`The separator can be any type of separator that allows the
`movement of lithium ions while isolating the positive and
`negative electrodes. These separators can be, for example,
`microporous membranes and non-woven fabrics mainly
`composed of polyolefins (for example, polyethylene,
`polypropylene).
`[0034] (4) Non-aqueous Electrolyte
`The non-aqueous electrolyte is prepared, for example, by
`dissolving an electrolyte in a non-aqueous solvent.
`[0035] Examples of the non-aqueous solvent can be
`ethylene carbonate (EC), propylene carbonate (PC),
`butylene carbonate (BC), dimethyl carbonate (DMC),
`diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-
`butyrolactone
`(γ-BL),
`sulfolane,
`acetonitrile,
`1,2-
`dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether,
`tetrahydrofuran (THF), 2- methyltetrahydrofuran, and the
`like. The aforementioned non-aqueous solvents may be
`used alone or in a mixture of two or more types.
`[0036] Examples of the electrolyte include lithium salts
`lithium
`(LiClO4),
`such
`as
`lithium
`perchlorate
`hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4),
`lithium
`(LiAsF6),
`lithium
`arsenic
`hexafluoride
`trifluoromethanesulfonate (LiCF3SO3), and the like. The
`electrolytes may be used alone or in a mixture of two or
`more types.
`
`
`JLab/Cambridge, Exh. 1039, p. 4
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`
`

`

`[0037] The dissolution amount of the electrolyte in the non-
`aqueous medium should be in the range of 0.2 mol/L to 2 mol/L.
`[0038] An example of a flat-type non-aqueous secondary battery is
`illustrated in FIGS. 1-5. FIG. 1 is a cross-sectional view of an
`example of a flat-type non-aqueous secondary battery (for example,
`a coin-type non-aqueous secondary battery).
`[0039] An electrode group 4 is stored in a sealed container in which
`a cylindrical positive electrode container with bottom (outer can) 1
`is crimped and fixed to a cylindrical negative electrode container
`with bottom (cap) 2 via an insulating gasket 3. The electrode group
`4 is fabricated, for example, by being rolled in a spiral shape with
`a separator 5 interposed between the positive electrode and the
`negative electrode. a negative electrode current collector 6
`protrudes from one roll surface of the electrode group 4, and the
`protruding negative electrode current collector 6 is bent to the inner
`circumference and contacts the inner surface of the negative
`electrode container 2. Furthermore, the positive electrode current
`collector 7 protrudes from the second roll surface of the electrode
`group 4, and the protruding positive electrode current collector 7 is
`bent to the inner circumference and contacts the inner surface of
`the positive electrode container 1. The non-aqueous electrolyte is
`impregnated in the electrode group 4.
`[0040] This flat-type non-aqueous secondary battery of the present
`invention described above has a sealed container obtained by
`crimping and fixing a positive electrode container and a negative
`electrode container via an insulating gasket, and an electrode group
`which is stored in the sealed container and is composed of a spirally
`rolled laminated member having a positive electrode including a
`positive electrode current collector and a negative electrode
`including a negative electrode current collector. An end part of the
`positive electrode current collector or the negative electrode
`current collector is made to protrude from one of the roll surfaces
`electrode group, and the protruding end part is bent to contact the
`inner surface of the positive electrode container or the negative
`electrode container having the same electrode as the protruding end
`part.
`[0041] If the length of the electrode group in the direction
`perpendicular to the roll axis is made longer than the length in the
`roll axis direction in order to increase the energy density of the flat
`battery, the electrode group is easily deformed into a telescoping
`roll shape by handling or the like during manufacturing, resulting
`in roll shifting and disintegration. According to the present
`application, even when the length in the direction perpendicular to
`the roll axis is longer than the length in the direction of the roll axis
`of the electrode group, the electrodes and separator near the center
`of the roll surface can be restrained from protruding outward by
`the bent part, thereby reducing roll shifting and disintegration of
`the electrode group during manufacturing.
`[0042] In addition, the edge protruding from the roll surface is bent
`without a notch, so a repulsive force that attempts to return the bent
`part to the original shape can easily act, and thus the contact area
`between the protruding edge and the inner surface of the container
`can be improved. As a result, the internal resistance of the battery
`can be reduced and the discharge capacity can be enhanced.
`[0043]
`[Examples] An example of the present invention will be described
`below in detail while referring to the drawings.
`[0044] FIG. 2 is a plan view illustrating the positional relationship
`between the positive electrode, the negative electrode, and the
`separator of the electrode group in the coin-type non-aqueous
`
`(4) 2003-31266 (P2003-31266A)
`
`secondary battery of FIG. 1; FIG. 3 is a cross-sectional view along
`line III-III of FIG. 2; FIG. 4 is a schematic view illustrating a rolled
`body in which the positive electrode, the separator and the negative
`electrode of FIG. 2 are rolled in a spiral shape; and FIG. 5 is a
`cross-sectional view illustrating a state in which the negative
`electrode collector protruding from one roll surface of the rolled
`body of FIG. 4 is bent to the inner circumference.
`[0045] (Example 1)
`Preparation of the Positive Electrode: The positive electrode slurry
`was prepared by dissolving 3 parts by mass of polyvinylidene
`fluoride (product name: #1100 manufactured by Kureha Chemical
`Industry) in 25 parts by mass of N-methylpyrrolidone, then adding
`89 parts by mass of LiCoO2 with an average particle diameter of 3
`μm as a positive electrode active material and 8 parts by mass of
`graphite (product name: KS6 manufactured by Lonza) as a
`conductive material, then stirring and mixing using a dissolver and
`a bead mill. The slurry was applied to both sides of 15 μm thick
`aluminum foil as a current collector at regular intervals using a die
`coater, dried, pressed, and slit to obtain a reel-shaped positive
`electrode 9 having a width of 3.5 mm and having the structure
`illustrated in FIG. 2, with a thickness of 200 μm, a width of the
`positive electrode active material-containing layer 8 of 2 mm, and
`a width of the positive electrode active material-containing layer
`non-retaining region 7 (positive electrode current collector) of 1.5
`mm.
`[0046] Preparation of the Negative Electrode: 10 mass parts of
`graphite powder (product name: KS15 manufactured by Lonza)
`were added and mixed into 100 mass parts of mesophase pitch-
`based carbon fiber powder (manufactured by Petca), and then 4.2
`mass parts of styrene/butadiene latex (product name: L1571
`manufactured by Asahi Kasei Corporation, solid content 48% by
`weight), 130 mass parts of an aqueous solution (solid content 1%
`by weight) of carboxymethyl cellulose (product name: BSH12
`manufactured by Dai-ichi Kogyo Seiyaku) as a thickener, and 20
`mass parts of distilled water were added and mixed to prepare a
`slurry. The slurry was applied to both sides of a 10 μm thick copper
`foil at regular intervals using a die coater, dried, pressed, and slit
`to obtain a reel-shaped negative electrode 11 with a width of 4.5
`mm and having the structure illustrated in FIG. 2, a thickness of
`200 μm, a width of the negative electrode active material-
`containing layer 10 of 3 mm, and a width of the negative electrode
`active material-containing layer non-retaining region 6 (negative
`electrode current collector) of 1.5 mm.
`[0047] Preparation of the Electrode Group: A 4 mm wide strip of
`a porous polyethylene film was prepared as the separator 5. The
`active material-containing layer 8 of the positive electrode 9 was
`made to face the central portion of the active material-containing
`layer 10 of the negative electrode 11, the separator 5 was placed on
`the outer side of the positive electrode 9 between the negative
`electrode 11 and the positive electrode 9 so that the end part of the
`negative electrode current collector 6 protruded from one end of
`the long side of the separator 5, and the end of the positive
`electrode current collector 7 protruded from the second end. The
`laminated member that was obtained was rolled in a spiral shape,
`and as illustrated in FIG. 4, the roll end portion of the obtained
`rolled body 12 was secured with adhesive tape 13.
`[0048] Next, as illustrated in FIG. 5, the negative electrode current
`collector 6 protruding from one roll surface of the rolled body 12
`was bent down to the inner circumference every 90° such that the
`entire body was bent. Furthermore, the positive electrode current
`collector 7 protruding from the second roll surface of the roll body
`12 was bent to the inner circumference at 90° intervals
`
`
`
`
`
`JLab/Cambridge, Exh. 1039, p. 5
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`
`

`

`such that the entire body was bent to obtain an electrode group 4
`having a diameter of 20 mm and a height of 4.5 mm.
`[0049] Preparation of Non-aqueous Electrolyte: The non-aqueous
`electrolyte was prepared by mixing ethylene carbonate (EC) and γ-
`butyl lactone (γ-BL) at a 1:3 volume ratio and dissolving 1.5 mol/L
`of LiBF4 in the resulting mixed solvent as the electrolyte.
`[0050] Assembly of the battery: A 2450 size battery container (24
`mm in diameter and 5 mm in height) was used. The electrode group
`4 was stored in the positive electrode container 1 such that the bent
`part of the positive electrode current collector 7 is in contact with
`the bottom inner surface of the positive electrode container 1, and
`was subjected to reduced pressure drying at 80°C for 24 hours.
`Then, after cooling to room temperature, 0.6 g of the non-aqueous
`electrolyte was injected. An annular insulating gasket 3 was
`attached to the open end of the negative electrode container 2, the
`negative electrode container 2 was crimped and fixed to the
`positive electrode container 1, such that the bent part of the
`negative electrode current collector 6 comes into contact with the
`inner surface of the negative electrode container 2, so as to obtain
`a coin-type non-aqueous secondary battery having the structure
`illustrated in FIG. 1.
`[0051] (Example 2)
`Preparation of the Negative Electrode: A slurry similar to that
`described in Example 1 was applied to both sides of a 10 μm thick
`copper foil at regular intervals using a die coater, dried, pressed,
`and slit to obtain a reel-shaped negative electrode having a
`thickness of 200 μm, a width of the negative electrode active
`material-containing layer of 3 mm, and no negative electrode
`active material-containing
`layer non-retaining region. The
`negative electrode active material-containing layer at the end part
`in the short side direction of the negative electrode was removed,
`and then a nickel tab was welded to the negative electrode.
`[0052] Preparation of the Electrode Group: The active material-
`containing layer of the positive electrode was made to face the
`central portion of the active material-containing layer of the
`negative electrode, and then a separator similar to that described in
`Example 1 was placed between the positive electrode and the
`negative electrode and to the outside of the positive electrode, such
`that the end part of the positive electrode current collector
`protrudes from one end part of the long side of the separator. The
`obtained laminated member was rolled into a spiral shape, and the
`end part of the roll of the obtained rolled body was secured with
`adhesive tape.
`[0053] Next, the positive electrode current collector protruding
`from the second roll surface of the rolled body was bent to the inner
`circumference at 90° intervals such that the entire body was bent,
`so as to obtain an electrode group having a diameter of 20 mm and
`a height of 4.5 mm.
`[0054] Assembly of the battery: A battery container with a similar
`size to that described in Example 1 was used. The electrode group
`was stored in the positive electrode container such that the bent
`part of the positive electrode current collector and the bottom of
`the container are in contact, and then dried at 80°C for 24 hours
`under reduced pressure. Next, after cooling to room temperature,
`0.6 g of a non-aqueous electrolyte similar to that described in
`Example 1 was injected. An annular insulating gasket was attached
`to the open end of the negative electrode container, the negative
`electrode container was crimped and fixed to the positive electrode
`container, such that the negative electrode tab is in contact with the
`inner surface of the negative electrode container so as to obtain a
`coin-type non-aqueous secondary battery.
`[0055] (Comparative Example 1) First, the electrode group was
`fabricated by the method illustrated in FIGS. 6 and 7.
`
`(5) 2003-31266 (P2003-31266A)
`
`[0056] Preparation of the positive electrode: A slurry similar to that
`described in Example 1 was applied to both sides of a 15 μm thick
`aluminum foil as a current collector at regular intervals using a die
`coater, dried, pressed, and slit to obtain a reel-type positive
`electrode having a width of 3.0 mm, a thickness of 200 μm, a width
`of the positive electrode active material-containing layer of 2.0 mm,
`and a plain part having a width of 0.5 mm formed on both sides of
`the positive electrode active material-containing layer. The
`positive electrode active material-containing layer was removed at
`the end part 13 in the short side direction of the positive electrode,
`and an aluminum tab 14 was welded to the positive electrode.
`[0057] Preparation of the Negative Electrode: A slurry similar to
`that described in Example 1 was applied to both sides of a 10 μm
`thick copper foil at regular intervals using a die coater, dried,
`pressed, and slit to obtain a reel-shaped negative electrode having
`a thickness of 200 μm, a width of the negative electrode active
`material-containing layer of 3 mm, and no negative electrode
`active material-containing
`layer non-retaining region. The
`negative electrode active material-containing layer at the end part
`15 in the short side direction of the negative electrode was removed,
`and then a nickel tab 16 was welded to the negative electrode.
`[0058] Preparation of the Electrode Group: A 4 mm wide strip of
`a porous polyethylene film was prepared as the separator 17. The
`active material-containing layer of the positive electrode was made
`to face the central portion of the active material-containing layer
`of the negative electrode similar to that described in Example 2,
`and then a separator 17 similar to that described in Example 1 was
`placed between the positive electrode and the negative electrode.
`Continuing, a separator 17 was further placed on the positive
`electrode side of the laminate member. The resulting laminate
`member was rolled in a spiral shape, and the roll end part of the
`resulting rolled body was secured with adhesive tape 18 to obtain
`an electrode group 19 having separators protruding from both roll
`surfaces.
`[0059] Assembly of the Battery: A battery container with a similar
`size to that described in Example 1 was used. The electrode group
`was stored in the positive electrode container such that the positive
`electrode tabs are in contact with the inner surface of the container,
`and then dried at 80°C for 24 hours under reduced pressure. Next,
`after cooling to room temperature, 0.6 g of a non-aqueous
`electrolyte similar to that described in Example 1 was injected. An
`annular insulating gasket was attached to the open end of the
`negative electrode container, the negative electrode container was
`crimped and fixed to the positive electrode container, such that the
`negative electrode tab is in contact with the inner surface of the
`negative electrode container so as to obtain a coin-type non-
`aqueous secondary battery.
`[0060] (Comparative Example 2)
`Preparation of the Electrode Group: The rolled body was made in
`the same manner as described in Example 1. Notches parallel to
`the roll axis were formed at equal intervals in the negative
`electrode current collector protruding from one roll surface of the
`rolled body, and then the negative electrode current collector was
`bent to the inner circumference. Furthermore, notches parallel to
`the roll axis were formed at equal intervals in the positive electrode
`current collector protruding from the second roll surface of the
`rolled body, and then the positive electrode current collector was
`bent to the inner circumference to obtain an electrode group with a
`diameter of 20 mm and a height of 4.5 mm.
`[0061] Assembly of the Battery: A battery container with a similar
`size to that described in Example 1 was used. The electrode group
`was stored in the positive electrode container such that the bent
`part of the positive electrode current collector is in contact with the
`bottom inner surface of the positive electrode container, and was
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`JLab/Cambridge, Exh. 1039, p. 6
`JLab/Cambridge v. Varta, 2020-01212
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`(6) 2003-31266 (P2003-31266A)
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`subjected to reduced pressure drying at 80°C for 24 hours. Next,
`after cooling to room temperature, 0.6 g of a non-aqueous
`electrolyte similar to that described in Example 1 was injected. An
`annular insulating gasket was attached to the open end of the
`negative electrode container, the negative electrode container was
`crimped and fixed to the positive electrode container, such that the
`bent part of the negative electrode current collector comes into
`contact with the inner surface of the negative electrode container,
`so as to obtain a coin-type non-aqueous secondary battery.
`[0062] The secondary batteries obtained in Examples 1 and 2 and
`Comparative Examples 1 and 2 were filled with liquid and then
`aged at room temperature for 24 hours. Next, a charge-discharge
`cycle was performed by charging the battery for 10 hours at 10 mA
`corresponding to 0.2 C in a constant-current, constant-voltage
`system, and then discharged at 10 mA. Discharge capacity
`
`and internal resistance were measured at the 1st cycle, 50th cycle
`and 100th cycle, and the results are shown in Table 1.
`[0063] With respect to the secondary batteries of Examples 1 and
`2 and Comparative Examples 1 and 2, the number of pieces (out of
`100 electrode groups) in which roll shifting occurred in the
`electrode groups was measured by the method described below,
`and the results are shown in Table 1.
`[0064] In other words, the electrode group was dropped from a
`height of 20 cm and the shape was observed. A passing product
`had an increase in the vertical direction (roll axis direction) within
`+0.5 mm (total height of 5.0 mm maximum) of the electrode group,
`and prod