JP5537094B2 - battery - Google Patents

Description

  The present invention relates to a battery, and more particularly to a sealed secondary battery in which an electrode group, a lead, and a tab are fixed to an outer can and a lid so as to maintain insulation.

  With the advancement of electronic devices such as mobile phones and personal computers, secondary batteries used in these devices have been required to be smaller and lighter. As a secondary battery having a high energy density that can respond to this, a lithium ion secondary battery can be given. On the other hand, secondary batteries such as lead-acid batteries and nickel-metal hydride batteries are used as large-scale, large-capacity power sources such as electric vehicles, hybrid vehicles, electric motorcycles, and forklifts. Recently, lithium ions with high energy density are used. Development toward the adoption of secondary batteries is thriving. Lithium-ion secondary batteries that can respond to these demands have been developed for larger sizes and larger capacities while taking into consideration the long life and safety.

  As a power source for these applications, since the driving power is large, a battery pack containing a plurality of batteries connected in series or in parallel is used (for example, Patent Documents 1 and 2).

  Usually, the battery outer can is connected to the positive electrode potential or the negative electrode potential, but in the battery used for the assembled battery using a large number of batteries, the outer can becomes high voltage, so there is a risk of short circuit, Since there is a risk of electric leakage or electric shock to the human body, the outer can may be structured to be insulated from the electrode group and leads.

  In that case, the insulation between the outer can, the electrode group, the lead, and the like has been studied to have a structure in which the periphery is covered with a bag-shaped thin resin material or a plate-shaped resin material. However, in the case of a bag-shaped thin-walled resin material, there is a concern about tearing when inserted into an outer can. Further, in the case of a plate-like resin material, it becomes a cost increase factor such as an increase in the number of parts. Furthermore, both bag-shaped and plate-shaped resin materials have been harmful to downsizing due to volume increase.

JP 2009-87542 A JP 2009-87720 A

  An object of the present invention is to improve the volume efficiency of a battery having a structure in which an electrode group, a current collecting tab, and a lead are insulated from an outer can.

The battery of the present invention comprises a flat electrode group in which a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector are wound into a flat shape via a separator,
A positive electrode current collector tab comprising the positive electrode current collector projecting spirally from one end face of the electrode group;
A negative electrode current collector tab comprising the negative electrode current collector projecting spirally from the other end face of the electrode group;
An outer can in which the electrode group is stored;
A lid attached to the opening of the outer can and having a positive terminal and a negative terminal;
A positive electrode lead having one end electrically connected to the positive electrode terminal and the other end electrically connected to the positive electrode current collecting tab;
A negative electrode lead having one end electrically connected to the negative electrode terminal and the other end electrically connected to the negative electrode current collecting tab;
An insulating tape for insulating the outermost periphery of the electrode group;
A first insulating cover made of a resin molded product shaped to cover a portion of the positive electrode lead and the positive electrode current collecting tab facing the inner surface of the outer can;
A second insulating cover made of a resin molded product shaped to cover a portion of the negative electrode lead and the negative electrode current collecting tab facing the inner surface of the outer can ,
The first insulating cover has a convex portion projecting inwardly on a side plate facing the end face of the positive current collecting tab, and the second insulating cover faces the end face of the negative current collecting tab. The side plate has a convex portion protruding inward .

  ADVANTAGE OF THE INVENTION According to this invention, it has a structure which insulates an electrode group, a current collection tab, and a lead | read | reed from an exterior can, and can provide a battery with high volumetric efficiency.

The expansion | deployment perspective view which shows the battery of 1st Embodiment. The perspective view which shows the process of accommodating the electrode group in the battery of FIG. 1 in an armored can. The expansion | deployment perspective view which shows the electrode group of FIG. The perspective view which shows the 1st, 2nd insulating cover used for the battery of 2nd Embodiment. The perspective view which shows the electrode group used for the battery of 3rd Embodiment. The perspective view which shows typically the impregnation state of the electrolyte solution after the liquid injection in the battery of 3rd Embodiment.

  The batteries according to the first to third embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments.

(First embodiment)
The battery 20 shown in FIGS. 1 and 2 is a sealed prismatic non-aqueous electrolyte secondary battery. The battery 20 includes an outer can 1, a flat electrode group 2 accommodated in the outer can 1, positive and negative electrode leads 3 and 4 positioned in the outer can 1, and an insulating tape that covers the outermost periphery of the electrode group 2. 5, the first insulating cover 6, the second insulating cover 7, the insulating cover fixing tape 8, the lid 9 attached to the opening of the outer can 1, and the positive and negative terminals 10 provided on the lid 9. , 11.

  The outer can 1 has a bottomed rectangular tube shape, and is formed of a metal such as aluminum, an aluminum alloy, iron, or stainless steel, for example. An electrolytic solution (not shown) is accommodated in the outer can 1 and impregnated in the flat electrode group 2.

  As shown in FIG. 3, the flat electrode group 2 includes a positive electrode 12 and a negative electrode 13 wound in a flat shape with a separator 14 therebetween. The positive electrode 12 includes a strip-shaped positive electrode current collector made of, for example, a metal foil, a positive electrode current collector tab 12a composed of one end parallel to the long side of the positive electrode current collector, and at least the positive electrode current collector tab 12a. And a positive electrode active material layer 12b formed on the body. On the other hand, the negative electrode 13 is formed by excluding, for example, a strip-shaped negative electrode current collector made of a metal foil, a negative electrode current collector tab 13a having one end parallel to the long side of the negative electrode current collector, and at least the negative electrode current collector tab 13a. Negative electrode active material layer 13b.

  The positive electrode 12, the separator 14, and the negative electrode 13 are configured such that the positive electrode current collecting tab 12 a protrudes from the separator 14 in the winding axis direction of the electrode group, and the negative electrode current collecting tab 13 a protrudes from the separator 14 in the opposite direction. The positive electrode 12 and the negative electrode 13 are wound in a shifted position. As a result of such winding, as shown in FIG. 1, in the electrode group 2, the positive electrode current collecting tab 12a wound in a spiral shape protrudes from one end face, and is wound in a spiral form from the other end face. The negative electrode current collection tab 13a protrudes.

  As shown in FIG. 1, one end of the positive electrode lead 3 is electrically connected to the positive electrode current collecting tab 12a of the electrode group 2 by, for example, ultrasonic bonding. Note that the other end (not shown) of the positive electrode lead 3 is electrically connected to the positive electrode terminal 10. On the other hand, one end of the negative electrode lead 4 is electrically connected to the negative electrode current collecting tab 13a of the electrode group 2 by, for example, ultrasonic bonding. The other end (not shown) of the negative electrode lead 4 is electrically connected to the negative electrode terminal 11.

  The adhesive insulating tape 5 insulates the outermost periphery of the electrode group 2 from the outer can 1. In FIG. 1, the insulating tape 5 is in close contact with the outermost periphery of the electrode group 2 and covers the outermost periphery. This combines the winding function of the wound electrode group 2 and the insulating function between the electrode group 2 and the outer can 1. It also contributes to cost reduction by reducing the number of parts. Further, no new insulating material other than the insulating cover is required, and the insertion into the outer can 1 is facilitated, and the electrode group dimensions can be secured up to the inner dimensions of the outer can 1, thereby contributing to the improvement of volume efficiency. Further, since the positive and negative electrode current collecting tabs 12a and 13a at both ends of the electrode group 2 are not covered with the insulating tape 5, the insulating tape 5 does not hinder the impregnation of the electrolytic solution. The number of windings of the insulating tape 5 can be one or more. In the present embodiment, the electrode group 2 is wound in a flat shape, but it can also be applied to a stacked electrode group.

  Examples of the resin that can be used for the base material of the insulating tape 5 include polyester (PET), polyimide, polyphenylene sulfide (PPS), and polypropylene.

  The 1st insulating cover 6 consists of a resin molded product of the shape which covers the part which opposes the inner surface of the exterior can 1 in the positive electrode lead 3 and the positive electrode current collection tab 12a. Specifically, the first insulating cover 6 is composed of a flat cap that surrounds the end surface of the positive electrode current collecting tab 12a and a portion facing the inner surface of the outer can 1 on the outermost periphery of the positive electrode current collecting tab 12a. A portion facing the inner surface of the lid 5 is cut out to form an opening 6a. That is, the first insulating cover 6 includes an opening 6a, a side plate 6b that covers the end face of the positive current collecting tab 12a, and a side plate 6c that is curved in a U shape so as to cover the outermost periphery of the positive current collecting tab 12a. Have.

  The 2nd insulating cover 7 consists of a resin molded product of the shape which covers the part which opposes the inner surface of the armored can 1 in the negative electrode lead 4 and the negative electrode current collection tab 13a. Specifically, the second insulating cover 7 is composed of a flat cap that surrounds the end surface of the negative electrode current collecting tab 13a and a portion facing the inner surface of the outer can 1 on the outermost periphery of the negative electrode current collecting tab 13a. A portion facing the inner surface of the lid 5 is cut out to form an opening 7a. That is, the second insulating cover 7 includes an opening 7a, a side plate 7b covering the end face of the negative electrode current collecting tab 13a, and a side plate 7c curved in a U shape so as to cover the outermost periphery of the negative electrode current collecting tab 13a. Have.

  The first insulating cover 6 has a function of protecting the ultrasonic welded portion between the positive electrode lead 3 and the positive electrode current collecting tab 12a from vibration and impact, and a function of insulating the positive electrode lead 3 and the positive electrode current collecting tab 12a from the outer can. This also contributes to cost reduction by reducing the number of parts. The second insulating cover 7 has a function of protecting the ultrasonic welded portion between the negative electrode lead 4 and the negative electrode current collecting tab 13 a from vibration and impact, and the negative electrode lead 4 and the negative electrode current collecting tab 13 a from the outer can 1. It can also function as an insulation, contributing to cost reduction by reducing the number of parts. Further, by protecting the ultrasonic welded portion with the first and second insulating covers 6 and 7, the insertion property of the electrode group 2 into the outer can 1 is also improved.

  As shown in FIG. 2, the first insulating cover 6 is inserted into the end surface from which the positive electrode current collecting tab 12 a of the electrode group 2 protrudes, and the U-shaped side plate 6 c is overlaid on the insulating tape 5. It is fixed on the insulating tape 5 with a fixing tape 8. The second insulating cover 7 is inserted into the end face from which the negative electrode current collecting tab 13 a of the electrode group 2 protrudes, and the U-shaped side plate 7 c is overlaid on the insulating tape 5 and insulated by the insulating cover fixing tape 8. It is fixed on the tape 5. With this configuration, the electrode group 2, the positive and negative current collecting tabs 12 a and 13 a, and the positive and negative electrode leads 3 and 4 can be completely insulated from the outer can 1. In FIG. 2, the first and second insulating covers 6 and 7 are fixed on the insulating tape 5 with the insulating cover fixing tape 8, but the insulating tape 5 and the first and second insulating covers 6 and 6 are fixed. A method in which the insulating cover fixing tape 8 is not used is also conceivable.

  Examples of the resin that can be used for the first and second insulating covers 6 and 7 include polypropylene, polyimide, polyphenylene sulfide (PPS), and polyester (PET). Among these, polypropylene is desirable from the viewpoints of heat resistance, insulation, and cost.

  By the way, as shown in FIGS. 1 and 2, the positive terminal 10 is attached to the lid 9 via an insulating gasket 15 by, for example, caulking. The positive terminal 10 is also electrically connected to the positive lead 3 by caulking. Thereby, the positive electrode terminal 10 is electrically connected to the positive electrode 12 of the electrode group 2 via the positive electrode lead 3. The negative electrode terminal 11 is attached to the lid 9 via an insulating gasket 16 by caulking, for example. The negative electrode terminal 11 is also electrically connected to the negative electrode lead 4 by caulking. Thereby, the negative electrode terminal 11 is electrically connected to the negative electrode 13 of the electrode group 2 through the negative electrode lead 4.

  The lid 9 is attached to the opening portion of the outer can 1 by, for example, laser seam welding. The lid 9 is made of a metal such as aluminum, aluminum alloy, iron or stainless steel, for example. The lid 9 and the outer can 1 are preferably formed from the same type of metal.

  According to the battery of the first embodiment described above, the portions of the positive and negative current collecting tabs 12a and 13a and the positive and negative electrode leads 3 and 4 that face the inner surface of the outer can 1 are made of resin molded products. 2 with insulating covers 6 and 7. At the same time, the outermost periphery of the electrode group 2 is covered with the insulating tape 5. Thereby, the electrode group 2, the positive and negative electrode current collecting tabs 12a and 13a, and the positive and negative electrode leads 3 and 4 can be insulated from the outer can 1.

  Moreover, since both ends of the electrode group 2 are covered with the first and second insulating covers 6 and 7 made of a resin molded product, the electrode group 2 can be smoothly inserted into the outer can 1. Furthermore, since the electrodes other than both ends of the electrode group 2 are covered with the insulating tape 5, the volume of the insulating member necessary for insulation from the outer can 1 can be reduced. As a result, the volume of the electrode group 2 that can be accommodated in the outer can 1 can be increased, and high volume efficiency can be realized. Furthermore, since the insertability of the electrode group 2 into the outer can 1 is improved, it is possible to prevent the first and second insulating covers 6 and 7 and the insulating tape 5 from being damaged when inserted into the outer can 1. In addition, the number of parts required for insulation from the outer can can be reduced.

(Second Embodiment)
In the battery according to the second embodiment, the structure of the first and second insulating covers of the battery according to the first embodiment is changed in order to improve the impregnation property of the electrolytic solution or to prevent breakage of the electrode group inside the battery. Except for this, the configuration is the same as that of the first embodiment.

  FIG. 4 is a perspective view showing first and second insulating covers used in the battery of the second embodiment. In a sealed secondary battery, it is necessary to impregnate an electrode group with an electrolytic solution. The first and second insulating covers 6, 7 shown in FIGS. 1 and 2 have openings 6 a, 7 a at the upper ends, so the electrolyte injected from the liquid injection port of the lid 9 of the outer can 1 is The electrode group 2 is impregnated through the openings 6a and 7a. By the way, the first and second insulating covers 6 and 7 have the side plates 6b and 7b in close contact with the side surface of the outer can 1, while the inner surfaces of the U-shaped side plates 6c and 7c and the outer can 1 are slightly on the inner surface. There is a gap. In order to impregnate the electrode group 2 with the electrolytic solution accumulated in the gap, the first and second insulating covers 6 and 7 shown in FIG. 4 are arranged on the bottom of the U-shaped side plates 6c and 7c, A plurality of electrolyte holes 17 serving as flow paths to the group 2 are opened. Thereby, the electrolyte solution accumulated between the outer can 1 and the first and second insulating covers 6 and 7 can be effectively utilized.

  Further, as shown in FIG. 4, a convex portion 18 projecting inward (on the electrode group 2 side) can be provided on each of the side plates 6 b and 7 b of the first and second insulating covers 6 and 7. The convex portion 18 is inserted into the gap between the positive and negative current collecting tabs 12 a and 13 a of the electrode group 2. Since the projections 18 provided on the first and second insulating covers 6 and 7 prevent the electrode group 2 from moving when the battery is accidentally dropped or the like, the electrode group 2 inside the battery is prevented. The movement of can be eliminated. As a result, inconveniences such as the positive and negative electrode current collecting tabs 12a and 13a being deformed or damaged and the bonding with the positive and negative electrode leads 3 and 4 coming off are eliminated, so that the safety of the battery can be improved.

  Even if only one of the electrolytic solution hole 17 or the convex portion 18 is formed in the first and second insulating covers 6 and 7, both the electrolytic solution hole 17 and the convex portion 18 are provided as shown in FIG. May be.

  Hereinafter, except for using the first and second insulating covers 6 and 7 shown in FIG. 4, it has the structure shown in FIGS. 1 to 3 and is 100 mm (width) × 20 mm (thickness) × 100 mm (height). A square nonaqueous electrolyte secondary battery (Example 1) having a weight of about 500 g and a square nonaqueous electrolyte secondary battery (Example 2) having the same configuration as that of Example 1 except that no convex portion is provided. ) Was prepared. About Example 1, 2, the drop test was implemented on condition of the following. A polypropylene molded product was used for the first and second insulating covers 6 and 7, and polyester was used for the base material of the insulating tape 5.

  In the drop vibration test, each surface of the secondary battery was dropped from a height of 10 cm. This drop test was performed on all six surfaces. This was made into 1 cycle and repeated. The secondary battery of Example 1 provided with the convex portions 18 endured 3600 cycles. On the other hand, in Example 2 in which the convex portion 18 was not provided, there was a problem that the connecting portion between the positive and negative electrode leads 3 and 4 and the positive and negative current collecting tabs 12a and 13a was disconnected in 600 cycles. In addition, the same effect was confirmed also in the drop test from 1 m.

(Third embodiment)
The battery of the third embodiment is the same as that of the first embodiment except that the structure of the electrode group and the insulating tape of the battery of the first embodiment is changed in order to smoothly impregnate the electrode group with the electrolytic solution. It has the same configuration as. The first and second insulating covers used in the second embodiment can also be used in the third embodiment.

  As shown in FIG. 5, the flat electrode group 2 used in the third embodiment is preferably configured with a separator 14 on the outermost periphery. Thereby, since the electrolytic solution impregnation from the outermost periphery 14 of the electrode group proceeds, it can be avoided that the first and second insulating covers 6 and 7 and the insulating tape 5 obstruct the electrolytic solution impregnation. Examples of the separator 14 include olefinic microporous membranes, nonwoven fabrics made of olefinic fibers, nonwoven fabrics made of cellulosic fibers, and the like. The separator is preferred.

  The width A of the short side of the insulating tape 5 is adjusted by the dimensional relationship between the first and second insulating covers 6 and 7 and the insulating cover fixing tape 8, but is basically a positive or negative current collector. What is necessary is just to be able to coat the portion where the active material layer is formed (electrode portion) that can contact the outer can 1. The width A of the short side of the insulating tape 5 is desirably equal to or greater than the width B of the short side of the separator 14. Thereby, since the separator 14 can be covered with the insulating tape 5 having a mechanical strength stronger than that of the separator 14, damage to the separator 14 when the insulating cover 5 is attached to the electrode group can be reduced. Moreover, since the affixing of the insulating cover fixing tape 8 can be rough, it is preferable. Note that the width A of the short side of the insulating tape 5 is desirably set so that the long side of the insulating tape 5 does not overlap with the positive and negative current collecting tabs 12 a and 13 a of the electrode group 2. This is to prevent the insulating tape 5 from interfering with the welding between the positive and negative electrode leads 3 and 4 and the positive and negative electrode current collecting tabs 12a and 13a.

  The thickness of the base material of the insulating tape 5 is not particularly limited as long as the insulation of the electrode group 2 can be ensured. If the thickness is increased, the capacity is reduced due to a decrease in the volume of the electrode group. A more preferable range is 0.025 mm or more and 0.2 mm or less.

  In the first and second embodiments, the outermost periphery of the electrode group 2 is covered with the insulating tape 5 for one turn or more, but can be made less than one turn. In this case, in order to insulate the outermost periphery of the electrode group 2, the outermost periphery of the electrode group 2 is constituted by the separator 14. The position at which the outermost periphery of the electrode group 2 is exposed is preferably on the side opposite to the liquid injection port where the electrolytic solution pools during liquid injection. Although the function of impregnating the electrolytic solution is performed also on the liquid injection side, it is necessary to draw the electrolytic solution to the liquid injection side at the time of impregnation, and complicated work such as reversing the posture of the cell at that time is required. Further, it is essential that the exposed portion of the electrode group 2 is a separator 14 in order to ensure insulation from the outer can 1. For example, as shown in FIG. 5, it is desirable that the portion of the electrode group 2 that faces the bottom surface of the outer can 1 is not covered with the insulating tape 5 and the outermost separator 14 is exposed. FIG. 6 is a perspective view in which the electrode group in FIG. 5 is housed in the outer can 1 without being covered with the first and second insulating covers 6 and 7 for the sake of convenience in order to explain the electrolytic solution impregnation step. The electrolytic solution is injected from a liquid injection port 19 provided in the lid 9 after the electrode group 2 is inserted into the outer can 1 and the lid 9 is welded to the opening of the outer can 1. Although a part of the electrolytic solution is impregnated in the electrode group 2, the remaining electrolytic solution 21 accumulates at the bottom of the outer can 1. The electrode group 2 is impregnated with the electrolytic solution 21 by repeating the pressurization and depressurization while the electrolytic solution 21 is accumulated in the bottom of the can. At this time, the electrolytic solution 21 is impregnated from a portion where the outermost separator 14 of the electrode group 2 is exposed. Therefore, it is necessary that the exposed portion of the separator 14 is in contact with the place where the electrolytic solution is accumulated after the injection.

  By adopting the configuration as described above, the number of parts of the insulating member can be reduced, the adverse effect on the miniaturization due to the increase in the volume of the insulating member can be avoided, and the impregnation property of the electrolytic solution can be improved to increase the productivity. It becomes possible to raise.

  Here, typical positive and negative electrode terminal materials in the first to third embodiments will be described. In the case of a lithium ion secondary battery using a carbon-based material for the negative electrode active material, the positive electrode terminal is generally made of aluminum or an aluminum alloy, and the negative electrode terminal is made of a metal such as copper, nickel, or nickel-plated iron. used. When lithium titanate is used as the negative electrode active material, in addition to the above, aluminum or an aluminum alloy may be used for the negative electrode terminal. When aluminum or an aluminum alloy is used for the positive and negative electrode terminals, the positive and negative current collecting tabs and the positive and negative electrode leads are preferably formed from aluminum or an aluminum alloy.

  Hereinafter, the positive electrode, the negative electrode, the separator, and the electrolytic solution used in the prismatic nonaqueous electrolyte secondary batteries of the first to third embodiments will be described.

  The positive electrode is produced, for example, by applying a slurry containing a positive electrode active material to a current collector made of an aluminum foil or an aluminum alloy foil. Although it does not specifically limit as a positive electrode active material, The oxide, sulfide, polymer, etc. which can occlude / release lithium can be used. Preferable active materials include lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium iron phosphate, and the like that can obtain a high positive electrode potential. The negative electrode is produced by applying a slurry containing a negative electrode active material to a current collector made of an aluminum foil or an aluminum alloy foil. The negative electrode active material is not particularly limited, and metal oxides, metal sulfides, metal nitrides, alloys, and the like that can occlude and release lithium can be used. Preferably, the lithium ion occlusion and release potential is metal lithium. It is a substance that becomes noble 0.4V or more with respect to the potential. Since the negative electrode active material having such a lithium ion storage / release potential can suppress the alloy reaction between aluminum or an aluminum alloy and lithium, it is possible to use aluminum or an aluminum alloy for a negative electrode current collector and a negative electrode related component. And For example, there are titanium oxide, lithium titanium composite oxide such as lithium titanate, tungsten oxide, amorphous tin oxide, tin silicon oxide, silicon oxide, etc. Among them, lithium titanium composite oxide is preferable. As the separator, a microporous film, a woven fabric, a non-woven fabric, a laminate of the same material or different materials among these can be used. Examples of the material for forming the separator include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-butene copolymer.

As the electrolytic solution, a nonaqueous electrolytic solution prepared by dissolving an electrolyte (for example, lithium salt) in a nonaqueous solvent is used. Examples of the non-aqueous solvent include 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. Nonaqueous solvents may be used alone or in combination of two or more. Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), and trifluorometa. A lithium salt such as lithium sulfonate (LiCF ₃ SO ₃ ) can be given. The electrolyte may be used alone or in combination of two or more. The amount of electrolyte dissolved in the non-aqueous solvent is desirably 0.2 mol / L to 3 mol / L.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
Hereinafter, the invention described in the scope of claims at the beginning of the application of the present application will be added.
[1] A flat electrode group in which a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector are wound into a flat shape via a separator;
A positive electrode current collector tab comprising the positive electrode current collector projecting spirally from one end face of the electrode group;
A negative electrode current collector tab comprising the negative electrode current collector projecting spirally from the other end face of the electrode group;
An outer can in which the electrode group is stored;
A lid attached to the opening of the outer can and having a positive terminal and a negative terminal;
A positive electrode lead having one end electrically connected to the positive electrode terminal and the other end electrically connected to the positive electrode current collecting tab;
A negative electrode lead having one end electrically connected to the negative electrode terminal and the other end electrically connected to the negative electrode current collecting tab;
An insulating tape for insulating the outermost periphery of the electrode group;
A first insulating cover made of a resin molded product shaped to cover a portion of the positive electrode lead and the positive electrode current collecting tab facing the inner surface of the outer can;
A battery comprising: a second insulating cover made of a resin molded product having a shape covering a portion of the negative electrode lead and the negative electrode current collecting tab facing the inner surface of the outer can.
[2] The battery according to [1], wherein the insulating tape covers the outermost periphery of the electrode group one or more times.
[3] [1] or [2], wherein the first insulating cover or the second insulating cover has a plurality of holes serving as flow paths between the outer can and the electrode group. Battery.
[4] The first insulating cover has a convex portion projecting inwardly on a side plate facing the end face of the positive current collecting tab, and the second insulating cover is an end face of the negative current collecting tab. The battery according to any one of [1] to [3], wherein the side plate opposed to each other has a convex portion protruding inward.
[5] The battery according to any one of [1] to [4], wherein an outermost periphery of the electrode group includes the separator.
[6] The battery according to [5], wherein the width of the short side of the insulating tape is equal to or greater than the width of the short side of the separator.
[7] The battery according to [5] or [6], wherein the insulating tape partially covers the outermost periphery of the electrode group, and the separator on the outermost periphery of the electrode group is exposed. .
[8] The battery according to [7], wherein a portion of the electrode group where the separator on the outermost periphery is exposed is provided in contact with an electrolytic solution stored in the outer can.
[9] The battery according to any one of [1] to [8], wherein the insulating tape has a base material thickness in a range of 0.012 mm to 0.2 mm.

  DESCRIPTION OF SYMBOLS 1 ... Exterior can, 2 ... Electrode group, 3 ... Positive electrode lead, 4 ... Negative electrode lead, 5 ... Insulating tape, 6 ... 1st insulating cover, 7 ... 2nd insulating cover, 8 ... Insulating tape, 9 ... Cover, DESCRIPTION OF SYMBOLS 10 ... Positive electrode terminal, 11 ... Negative electrode terminal, 12 ... Positive electrode, 12a ... Positive electrode current collection tab, 13 ... Negative electrode, 13a ... Negative electrode current collection tab, 14 ... Separator, 15, 16 ... Insulation gasket, 17 ... Electrolyte hole, 18 ... convex part, 20 ... battery, 21 ... electrolyte solution.

Claims (8)

A flat electrode group in which a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector are wound into a flat shape via a separator;
A positive electrode current collector tab comprising the positive electrode current collector projecting spirally from one end face of the electrode group;
A negative electrode current collector tab comprising the negative electrode current collector projecting spirally from the other end face of the electrode group;
An outer can in which the electrode group is stored;
A lid attached to the opening of the outer can and having a positive terminal and a negative terminal;
A positive electrode lead having one end electrically connected to the positive electrode terminal and the other end electrically connected to the positive electrode current collecting tab;
A negative electrode lead having one end electrically connected to the negative electrode terminal and the other end electrically connected to the negative electrode current collecting tab;
An insulating tape for insulating the outermost periphery of the electrode group;
A first insulating cover made of a resin molded product shaped to cover a portion of the positive electrode lead and the positive electrode current collecting tab facing the inner surface of the outer can;
A second insulating cover made of a resin molded product shaped to cover a portion of the negative electrode lead and the negative electrode current collecting tab facing the inner surface of the outer can ,
The first insulating cover has a convex portion projecting inwardly on a side plate facing the end face of the positive current collecting tab, and the second insulating cover faces the end face of the negative current collecting tab. A battery having a convex portion projecting inwardly on a side plate .   The battery according to claim 1, wherein the insulating tape covers the outermost periphery of the electrode group one or more times.   3. The battery according to claim 1, wherein the first insulating cover or the second insulating cover has a plurality of holes serving as a flow path between the outer can and the electrode group. The battery according to any one of claims 1 to 3, wherein an outermost periphery of the electrode group is configured by the separator. The battery according to claim 4 , wherein the width of the short side of the insulating tape is equal to or greater than the width of the short side of the separator. The battery according to claim 4 or 5 , wherein the insulating tape partially covers the outermost periphery of the electrode group, and the separator on the outermost periphery of the electrode group is exposed. The battery according to claim 6 , wherein a portion of the electrode group on the outermost periphery where the separator is exposed is provided so as to be in contact with an electrolytic solution stored in the outer can. The battery according to any one of claims 1 to 7 , wherein the insulating tape has a base material thickness in a range of 0.012 mm to 0.2 mm.

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