JP2015060654A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery which enables easy expansion control without impairing the sealability.SOLUTION: According to one embodiment, a battery includes: an exterior member 1; an electrode group 2; an electrolyte; a liquid injection port 14a; a first sealing lid 17; a second opening part 14b; a resin content sheet 19 having a gas venting hole 18; and a second sealing lid 23. The liquid injection port 14a is formed by a first opening part opened in the exterior member 1. The first sealing lid 17 seals the liquid injection port. The second opening part 14b is opened in the exterior member 1. The resin content sheet 19 is disposed on an inner surface of the exterior member 1 and faces the second opening part 14b. The second sealing lid 21 is disposed on an outer surface of the exterior member 1 and seals the second opening part 14b.

Description

  Embodiments described herein relate generally to a battery.

  As a large-sized and large-capacity power source used for an electric vehicle (EV), a hybrid vehicle (HEV), an electric motorcycle, a forklift, and the like, a non-aqueous electrolyte battery (for example, a lithium ion battery) having a high energy density has attracted attention.

  In order for lithium-ion batteries to become widespread as large-scale and large-capacity power supplies, various issues such as improved safety, increased capacity (higher energy density), longer life, higher input / output characteristics, and lower costs It is necessary to clear. When entering the automobile industry, safety improvements and cost reductions are essential.

  In particular, with regard to cost reduction, the cost reduction of raw materials is progressing very much along with the improvement of manufacturing, and each battery manufacturer is required to establish a simple manufacturing method and to use cheap raw materials. For this reason, there is a demand for realizing a battery that can easily control the swelling of the battery and has excellent sealing properties even when manufactured by a simple method at a low cost regardless of the manufacturing method.

JP 2000-353547 A JP 2006-331828 A JP 2007-59145 A JP 2007-257842 A JP 2008-41548 A

  The problem to be solved by the present invention is to provide a battery that does not impair hermeticity and is easy to control swelling.

  According to the embodiment, an exterior member, an electrode group, a liquid injection port, a first sealing lid, a second opening, a resin-containing sheet having a vent hole, and a second sealing lid A battery is provided. The electrode group is accommodated in the exterior member. The electrolytic solution is impregnated in the electrode group. The liquid injection port includes a first opening that is opened in the exterior member. The first sealing lid seals the liquid injection port. The second opening is opened in the exterior member. The resin-containing sheet is disposed on the inner surface of the exterior member and faces the second opening. The second sealing lid is disposed on the outer surface of the exterior member and seals the second opening.

FIG. 1 is a perspective view of an example battery according to the embodiment. FIG. 2 is a top view of the battery of FIG. FIG. 3 is an exploded perspective view of a main part of the battery shown in FIG. FIG. 4 is an exploded perspective view of a main part of the battery shown in FIG. FIG. 5 is a partially developed perspective view of the electrode group of the battery shown in FIG. FIG. 6 is a partial cross-sectional view of the sealing plate of the battery shown in FIG. FIG. 7 is a partial cross-sectional view showing the sealing plate before opening the gas vent hole. FIG. 8 is a cross-sectional view showing the gas release step. FIG. 9 is a cross-sectional view showing the second opening after sealing. FIG. 10 is a cross-sectional view showing a resin-containing sheet. FIG. 11 is a partial cross-sectional view showing a sealing plate before opening a vent hole in a battery of a comparative example. FIG. 12 is a cross-sectional view showing a gas releasing step in the battery of the comparative example. FIG. 13 is a cross-sectional view showing a state where the resin-containing sheet is removed from the battery of the comparative example. FIG. 14 is a cross-sectional view showing the second opening after sealing the battery of the comparative example.

  Lithium ion batteries are repeatedly charged and discharged, so that impurities, moisture, or electrolyte present in the battery cause a chemical reaction to generate gas. The battery can may be deformed by the internal pressure, and it is known that the prismatic lithium ion secondary battery is particularly susceptible to deformation. Therefore, when manufacturing a prismatic lithium ion secondary battery, after injecting the electrolyte, temporarily seal the injection port with a rubber plug, etc., perform initial charging, remove the rubber plug after charging, release the gas, A series of degassing processes are performed in which the liquid mouth is fully sealed. It is necessary to perform this degassing process more easily and at low cost.

  The battery of the embodiment includes a first opening and a second opening that are opened in the exterior member. The first opening is a liquid injection port for injecting the electrolytic solution into the electrode group, and is sealed by the first sealing lid. On the other hand, the second opening portion faces the resin-containing sheet having a gas vent hole, and the resin-containing sheet is fixed to the inner surface of the exterior member. When the gas generated in the exterior member in the manufacturing process is released to the outside from the gas vent hole of the resin-containing sheet, the initial amount of gas in the exterior member can be reduced. Battering of the battery when this occurs can be suppressed. In addition, since the liquid injection is performed through the first opening, the electrolyte and impurities do not adhere to the inner surface of the second opening. Furthermore, since the resin-containing sheet is fixed to the inner surface of the exterior member, the second sealing lid is fixed to the outer surface of the exterior member after the gas is released from the gas vent hole of the resin-containing sheet, and the second When the opening is sealed with the second sealing lid, since the resin-containing sheet does not hinder the sealing, the sealing reliability by the second sealing lid can be kept high. Accordingly, it is possible to provide a battery that can suppress swelling due to gas generation during use and has high sealing reliability.

  The resin-containing sheet preferably has metal adhesion. Specifically, it is desirable that the portion facing the inner surface of the exterior member is made of a metal adhesive resin. For such a resin-containing sheet, for example, a laminate film including a metal adhesive resin layer, a resin layer, and a metal layer disposed between the metal adhesive resin layer and the resin layer can be used. Examples of the metal adhesive resin include acid-modified polypropylene and acid-modified polyethylene. Examples of the resin layer include, for example, a polymer material having corrosion resistance against an electrolytic solution such as nylon and polyethylene terephthalate (PET). The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. The kind of material used for each layer can be one kind or two or more kinds. Moreover, you may fix a resin containing sheet to the inner surface of an exterior member with an adhesive instead of the heat bonding by the resin containing sheet which has metal adhesiveness.

  Hereinafter, embodiments will be described with reference to the drawings. In the following description, constituent elements that exhibit the same or similar functions are denoted by the same reference numerals throughout the drawings, and redundant descriptions are omitted.

  Hereinafter, an example of the battery according to the first embodiment will be described with reference to the drawings.

As shown in FIG. 1, the battery includes an exterior member 1, a flat electrode group 2 housed in the exterior member 1, and a nonaqueous electrolyte solution (not shown) impregnated in the flat electrode group 2. . The exterior member 1 has a bottomed rectangular tube-shaped container 3 and a sealing plate 4 fixed to the opening of the container 3 by welding, for example.

  As shown in FIG. 5, the flat electrode group 2 has a positive electrode 5 and a negative electrode 6 wound in a flat shape with a separator 7 therebetween. The positive electrode 5 is a positive electrode except for a strip-shaped positive electrode collector made of, for example, a metal foil, a positive electrode current collector tab 5a having one end parallel to the long side of the positive electrode current collector, and at least the positive electrode current collector tab 5a portion. And a positive electrode active material-containing layer 5b formed on the current collector. On the other hand, the negative electrode 6 excludes, for example, a strip-shaped negative electrode current collector made of a metal foil, a negative electrode current collector tab 6a formed of one end parallel to the long side of the negative electrode current collector, and at least a portion of the negative electrode current collector tab 6a. And a negative electrode active material-containing layer 6b formed on the negative electrode current collector.

  In the positive electrode 5, the separator 7, and the negative electrode 6, the positive electrode current collecting tab 5 a protrudes from the separator 7 in the winding axis direction of the electrode group, and the negative electrode current collecting tab 6 a protrudes from the separator 7 in the opposite direction. Thus, the positive electrode 5 and the negative electrode 6 are wound with the positions shifted. As a result of such winding, as shown in FIG. 5, the electrode group 2 has the positive electrode current collecting tab 5a wound spirally from one end face and is wound spirally from the other end face. The negative electrode current collection tab 6a protrudes.

  As shown in FIGS. 3 and 4, the positive lead 8 has a connecting plate 8 a for electrical connection with the positive terminal 9, a through hole 8 b opened in the connecting plate 8 a, and a bifurcated branch from the connecting plate 8 a. And a strip-shaped current collector 8c extending downward. The current collecting portion 8c of the positive electrode lead 8 sandwiches the positive electrode current collecting tab 5a of the electrode group 2 therebetween, and is electrically connected to the positive electrode current collecting tab 5a by welding. On the other hand, the negative electrode lead 10 has a connection plate 10a for electrical connection with the negative electrode terminal 11, a through hole 10b opened in the connection plate 10a, a strip that branches off from the connection plate 10a and extends downward. And a current collector 10c. The current collecting part 10c of the negative electrode lead 10 sandwiches the negative electrode current collecting tab 6a of the electrode group 2 therebetween, and is electrically connected to the negative electrode current collecting tab 6a by welding. The method for electrically connecting the positive and negative electrode leads 8 and 10 to the positive and negative electrode current collecting tabs 5a and 6a is not particularly limited, and examples thereof include welding such as ultrasonic welding and laser welding.

  The insulating member 12 includes a side plate 12a that covers the end faces of the positive and negative current collecting tabs 5a and 6a, and a side plate 12b that is curved in a U shape so as to cover the outermost periphery of the positive and negative current collecting tabs 5a and 6a. The upper end of the insulating member 12 is opened to accommodate the electrode group 2 therefrom. The positive electrode current collecting tab 5a of the electrode group 2 is covered with the insulating member 12 in a state where the current collecting portion 8c of the positive electrode lead 8 is welded. The connection plate 8 a of the positive electrode lead 8 is located above the insulating member 12. On the other hand, the negative electrode current collecting tab 6a of the electrode group 2 is covered with the insulating member 12 in a state where the current collecting portion 10c of the negative electrode lead 10 is welded. The connection plate 10 a of the negative electrode lead 10 is located above the insulating member 12. The two insulating members 12 are fixed to the electrode group 2 with an insulating tape 13.

  As shown in FIGS. 1 to 4, the sealing plate 4 has a rectangular plate shape. As shown in FIG. 4, the sealing plate 4 includes through holes 4 a and 4 b for attaching the positive and negative terminals 9 and 11, a liquid injection port 14 a composed of a circular first opening, and a circular second opening. Part 14b. Moreover, the sealing board 4 has the gas exhaust valve 15 near the center, as shown in FIG.1 and FIG.2. The gas discharge valve 15 includes a thin portion formed in an X shape on the sealing plate 4. When the pressure in the exterior member 1 increases due to the generation of gas and reaches a predetermined value, the thin-walled portion is broken, and the gas is released to the outside from the broken portion.

  The liquid injection port 14 a is for injecting the electrolytic solution into the exterior member 1. As shown in FIG. 6, the rubber plug 16 is filled in the liquid injection port 14a. Note that the rubber plug 16 may or may not be used. The first sealing lid 17 made of a metal disk is fixed around the liquid injection port 14a on the outer surface of the sealing plate 4 by welding, for example. The resin-containing sheet 19 having the gas vent hole 18 near the center is fixed by thermal bonding around the second opening 14b on the inner surface of the sealing plate 4. The resin-containing sheet 19 has metal adhesiveness, and is, for example, a laminated film in which a metal adhesive resin layer 20, a metal layer 21, and a resin layer 22 are laminated in this order as shown in FIG. The metal adhesive resin layer 20 of the resin-containing sheet 19 is thermally bonded to the inner surface of the sealing plate 4. The second sealing lid 23 made of a metal disk is fixed around the second opening 14b on the outer surface of the sealing plate 4 by, for example, welding.

  The first and second sealing lids 17 and 23 are made of a metal such as aluminum or an aluminum alloy, for example. Moreover, the shape of the 1st, 2nd sealing lid | covers 17 and 23 is not limited to disk shape, It can change according to the shape of a liquid inlet. Laser welding, spot welding, ultrasonic welding, or the like can be used for welding the first and second sealing lids 17 and 23 and the sealing plate 4.

  As shown in FIG. 4, the insulating plate 24 has a recess 24a in which the connection plate 8a of the positive electrode lead 8 is stored at one end, and a recess 24b in which the connection plate 10a of the negative electrode lead 10 is stored at the other end. And have. An opening is formed between the recess 24a and the recess 24b, and the back surface of the sealing plate 4 is exposed. Further, the recess 24 a and the recess 24 b of the insulating plate 24 have through holes that communicate with the through holes 4 a and 4 b of the sealing plate 4, respectively. The insulating plate 24 is disposed on the back surface of the sealing plate 4.

  The positive and negative terminals 9 and 11 respectively have rectangular plate-like projections 9a and 11a and shafts 9b and 11b extending from the projections 9a and 11a. The insulating gasket 25 has a through hole 25a into which the shaft portions 9b and 11b of the positive and negative terminals 9 and 11 are inserted. The shaft portion 9b of the positive electrode terminal 9 is inserted into the through hole 25a of the insulating gasket 25, the through hole 4a of the sealing plate 4, the through hole of the insulating plate 24, the through hole 8b of the connection plate 8a of the positive electrode lead 8, and these members It is fixed by caulking. Thereby, the positive electrode terminal 9 is electrically connected to the positive electrode current collecting tab 5 a via the positive electrode lead 8. On the other hand, the shaft portion 11 b of the negative electrode terminal 11 is inserted into the through hole 25 a of the insulating gasket 25, the through hole 4 b of the sealing plate 4, the through hole of the insulating plate 24, and the through hole 10 b of the connection plate 10 a of the negative electrode lead 10. It is fixed by caulking to the member. As a result, the negative electrode terminal 11 is electrically connected to the negative electrode current collecting tab 6 a via the negative electrode lead 10.

  According to such a battery, the second opening 14b is provided separately from the liquid injection port 14a, and the second opening 14b is covered with the resin-containing sheet 19 from the back surface side of the sealing plate 4, and the resin Since the gas vent hole 18 is opened in the containing sheet 19, the gas generated in the exterior member 1 in the manufacturing process (for example, aging) or the like is removed before the gas is sealed by the second sealing lid 23. Can be discharged to the outside. Although gas may be generated by subsequent charging and discharging or the like, since the original amount of gas in the exterior member 1 is small, it is possible to suppress swelling of the battery due to the generated gas. In addition, since the liquid injection is performed through the first opening 14a, the electrolytic solution and impurities do not adhere to the inner surface of the second opening 14b. Further, since the resin-containing sheet 19 is fixed to the inner surface of the sealing plate 4, after the gas is released from the gas vent hole 18 of the resin-containing sheet 19, the second opening is formed in the second sealing lid 23. When the sealing is performed, the resin-containing sheet 19 does not hinder the sealing, so that the sealing reliability by the second sealing lid 23 can be kept high. Accordingly, it is possible to provide a battery that can suppress swelling due to gas generation during use and has high sealing reliability.

  The gas vent hole 18 of the resin-containing sheet 19 is desirably opened after gas is generated in the manufacturing process. An example of this will be described with reference to FIGS.

  After injecting the electrolyte solution into the exterior member 1 from the injection port 14a, a rubber plug 16 is inserted into the injection port 14a, and the first sealing lid 17 is placed around the injection port 14a on the outer surface of the sealing plate 4. Fix by welding. At this time, the second opening 14b is covered with a resin-containing sheet 19 that is thermally bonded to the inner surface of the sealing plate 4 as shown in FIG. The resin-containing sheet 19 has not yet been vented. The battery in this state can obtain a withstand voltage of about 1 MPa or more. After the battery is first charged or initially charged / discharged, it is aged.

  Next, as shown in FIG. 8, when the resin-containing sheet 19 is pierced by the operation pin 26 (perforated member) having a sharp tip, the gas vent hole 18 is opened, and the gas in the exterior member 1 is degassed. Released through. It is desirable to release the gas in a sealed space such as a glove box. By discharging the gas in the sealed space and then collecting the gas in the sealed space, the gas can be prevented from diffusing over a wide range.

  Next, as shown in FIG. 9, the second sealing lid 23 is disposed on the outer surface of the sealing plate 4, the second sealing lid 23 covers the second opening 14 b, and the second sealing lid 23 Is sealed to the sealing plate 4 by welding.

  A charge / discharge cycle may be applied after the sealing step and before shipment.

  An example of the battery according to the embodiment described above is a lithium ion secondary battery. Hereinafter, the positive electrode, the negative electrode, the separator, the electrolytic solution, and the container that can be used in the battery according to the embodiment, and the structure and shape of the electrode group will be described in detail.

1) Positive Electrode The positive electrode can include a positive electrode current collector and a positive electrode active material-containing layer formed on a part of the surface of the current collector.

  The positive electrode active material-containing layer can contain a positive electrode active material, and optionally a conductive agent and a binder.

As the positive electrode active material, for example, an oxide or a sulfide can be used. Examples of oxides and sulfides include manganese dioxide (MnO ₂ ) that occludes lithium, iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (eg, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), Lithium nickel composite oxide (for example, Li _x NiO ₂ ), lithium cobalt composite oxide (for example, Li _x CoO ₂ ), lithium nickel cobalt composite oxide (for example, LiNi _1-y Co _y O ₂ ), lithium manganese cobalt composite oxide (e.g. _{Li x Mn y Co 1-y} O 2), lithium manganese nickel complex oxide having a spinel structure (e.g., _{Li x Mn 2-y Ni y} O 4), lithium phosphates having an olivine structure (e.g., Li _{x FePO 4, Li x Fe 1-} y Mn y PO 4, Li x CoPO 4), iron sulfate _{(Fe 2 (SO 4) 3} ), vanadium oxide (e.g. Examples thereof include V ₂ O ₅ ) and lithium nickel cobalt manganese composite oxide. In the above formula, 0 <x ≦ 1 and 0 <y ≦ 1. As the active material, these compounds may be used alone, or a plurality of compounds may be used in combination.

  The binder is blended to bind the active material and the current collector. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

  The conductive agent is blended as necessary in order to enhance the current collecting performance and suppress the contact resistance between the active material and the current collector. Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, and graphite.

  The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil containing at least one element selected from Mg, Ti, Zn, Ni, Cr, Mn, Fe, Cu, and Si.

  The positive electrode current collector is preferably integral with the positive electrode current collector tab. However, the positive electrode current collector may be separate from the positive electrode current collector tab.

  For the positive electrode, for example, a positive electrode active material, a binder, and a conductive agent blended as necessary are suspended in an appropriate solvent to prepare a slurry, and this slurry is applied to a positive electrode current collector and dried to dry the positive electrode active material. After the substance-containing layer is formed, it is manufactured by pressing. Or you may produce a positive electrode by forming the active material, a binder, and the electrically conductive agent mix | blended as needed in the shape of a pellet to make a positive electrode layer, and arrange | positioning this on a collector.

2) Negative electrode The negative electrode can include a negative electrode current collector and a negative electrode active material-containing layer formed on a part of the surface of the negative electrode current collector.

  The negative electrode active material-containing layer can contain a negative electrode active material and optionally a conductive agent and a binder.

  As the negative electrode active material, for example, a metal oxide, metal nitride, alloy, carbon, or the like that can occlude and release lithium ions can be used.

  The conductive agent is blended in order to improve current collecting performance and suppress contact resistance between the negative electrode active material and the current collector. Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, and graphite.

  The binder is blended to fill the gap between the dispersed negative electrode active materials and to bind the negative electrode active material and the current collector. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-based rubber, and styrene butadiene rubber.

  As the current collector, a material that is electrochemically stable at the lithium insertion and extraction potential of the negative electrode active material is used. The current collector is preferably made of copper, nickel, stainless steel or aluminum or an aluminum alloy containing at least one element selected from Mg, Ti, Zn, Mn, Fe, Cu and Si.

  The negative electrode current collector is preferably integral with the negative electrode current collector tab. The negative electrode current collector may be separate from the negative electrode current collector tab.

  The negative electrode is prepared by, for example, suspending a negative electrode active material, a binder and a conductive agent in a commonly used solvent to prepare a slurry. The slurry is applied to a current collector, dried, a negative electrode layer is formed, and then pressed. It is produced by giving. The negative electrode may also be produced by forming a negative electrode active material, a binder, and a conductive agent into a pellet to form a negative electrode layer, which is disposed on a current collector.

3) Separator The separator may be formed of, for example, a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), or a synthetic resin nonwoven fabric. Especially, since the porous film formed from polyethylene or a polypropylene can melt | dissolve at a fixed temperature and can interrupt | block an electric current, safety | security can be improved.

4) Electrolytic Solution As the electrolytic solution, for example, a nonaqueous electrolytic solution can be used.

  The non-aqueous electrolyte may be, for example, a liquid non-aqueous electrolyte prepared by dissolving an electrolyte in an organic solvent, or a gel-like non-aqueous electrolyte in which a liquid electrolyte and a polymer material are combined.

  The liquid non-aqueous electrolyte is preferably one in which the electrolyte is dissolved in an organic solvent at a concentration of 0.5 mol / L or more and 2.5 mol / L or less.

Examples of the electrolyte dissolved in the organic solvent include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), and lithium arsenic hexafluoride (LiAsF _6). ), Lithium trifluorometasulfonate (LiCF ₃ SO ₃ ), and lithium salts such as lithium bistrifluoromethylsulfonylimide [LiN (CF ₃ SO ₂ ) ₂ ], and mixtures thereof. The electrolyte is preferably one that is difficult to oxidize even at a high potential, and LiPF ₆ is most preferred.

  Examples of organic solvents include propylene carbonate (PC), ethylene carbonate (EC), cyclic carbonates such as vinylene carbonate; diethyl carbonate (DEC), dimethyl carbonate (DMC), chain like methyl ethyl carbonate (MEC) Carbonates; cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), dioxolane (DOX); chain ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); γ-butyrolactone (GBL), Acetonitrile (AN) and sulfolane (SL) are included. These organic solvents can be used alone or as a mixed solvent.

  Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

  Alternatively, the non-aqueous electrolyte may be a room temperature molten salt (ionic melt) containing lithium ions.

  A room temperature molten salt (ionic melt) refers to a compound that can exist as a liquid at room temperature (15 to 25 ° C.) among organic salts composed of a combination of an organic cation and an anion. The room temperature molten salt includes a room temperature molten salt that exists alone as a liquid, a room temperature molten salt that becomes liquid when mixed with an electrolyte, and a room temperature molten salt that becomes liquid when dissolved in an organic solvent. In general, the melting point of a room temperature molten salt used for a nonaqueous electrolyte battery is 25 ° C. or less. The organic cation generally has a quaternary ammonium skeleton.

5) Container As the container, a metal container can be used like the container 1 included in the battery described with reference to FIGS.

  As the metal container, for example, a metal container having a thickness of 1 mm or less can be used. The metal container is more preferably 0.5 mm or less in thickness, and still more preferably 0.2 mm or less.

  The shape of the container may be a flat type (thin type), a square type, a cylindrical type, a coin type, a button type, or the like. The container may be, for example, a small battery container loaded on a portable electronic device or the like, or a large battery container loaded on a two-wheeled or four-wheeled vehicle, depending on the battery size.

  The metal container is made of aluminum or an aluminum alloy. The aluminum alloy is preferably an alloy containing elements such as magnesium, zinc, and silicon. When the alloy contains a transition metal such as iron, copper, nickel, or chromium, the content is preferably 1% by mass or less.

  The container is not limited to a metal container. For example, a laminate film container can also be used.

6) Structure and shape of electrode group As long as the electrode group has a structure in which the positive electrode and the negative electrode face each other with a separator interposed therebetween, any structure can be adopted.

  For example, the electrode group can have a stack structure. The stack structure has a structure in which the positive electrode and the negative electrode described above are stacked with a separator interposed therebetween.

  Alternatively, the electrode group may have a wound structure. The wound structure is a structure in which the positive electrode and the negative electrode described above are stacked with a separator interposed therebetween, and the stacked body thus obtained is wound into a spiral shape or a flat spiral shape.

  The overall shape of the electrode group can be determined according to the container in which it is stored.

  The battery according to the embodiment described above has a second opening separately from the liquid injection port, covers the second opening from the inner surface side of the exterior member with a resin-containing sheet, and vents the resin-containing sheet. Since the holes are opened, it is possible to provide a battery that can suppress swelling due to gas generation during use and has high sealing reliability.

  On the other hand, as shown in FIG. 11, the battery of the comparative example in which the second opening 14 b is covered with the resin-containing sheet 19 by thermally bonding the resin-containing sheet 19 to the outer surface side of the sealing plate 4 is about 1 MPa. A breakdown voltage can be obtained. After the gas is generated in the exterior member, as shown in FIG. 12, the resin containing sheet 19 is pierced from the outside by the operation pin 26 to open the gas vent hole 18, and the gas is released from the gas vent hole 18. Thereafter, as shown in FIG. 13, the resin-containing sheet 19 is removed from the surface of the sealing plate 4. However, since it is difficult to completely remove the resin-containing sheet 19, a part 27 remains attached to the outer surface of the sealing plate 4. . In this state, when the second sealing lid 23 is welded to the outer surface of the sealing plate 4, a portion 27 of the resin is sandwiched between the sealing plate 4 and the second sealing lid 23 as shown in FIG. As a result, defects such as defective pinholes occur, and the pressure resistance of the battery of the comparative example is about 1 MPa.

  On the other hand, according to the battery of the embodiment, since the resin-containing sheet is fixed to the inner surface of the sealing plate, a pressure strength of at least about 2 MPa can be obtained, and a pressure strength of twice or more that of the battery of the comparative example can be realized. it can.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Exterior member, 2 ... Electrode group, 3 ... Container, 4 ... Sealing plate, 5 ... Positive electrode, 5a ... Positive electrode current collection tab, 5b ... Positive electrode active material content layer, 6 ... Negative electrode, 6a ... Negative electrode current collection tab, 6b DESCRIPTION OF SYMBOLS ... Negative electrode active material content layer, 7 ... Separator, 9 ... Positive electrode terminal, 11 ... Negative electrode terminal, 12 ... Insulating member, 13 ... Insulating tape, 14a ... Liquid injection port, 14b ... 2nd opening part, 17 ... 1st Sealing lid, 18 ... gas venting hole, 19 ... resin-containing sheet, 20 ... metal adhesive resin layer, 21 ... metal layer, 22 ... resin layer, 23 ... second sealing lid, 24 ... insulating plate, 25 ... Insulating gasket, 26 ... acting pin.

Claims (2)

An exterior member;
An electrode group housed in the exterior member;
An electrolytic solution impregnated in the electrode group;
A liquid injection port including a first opening opened in the exterior member;
A first sealing lid for sealing the liquid injection port;
A second opening opened in the exterior member;
A resin-containing sheet disposed on the inner surface of the exterior member so as to face the second opening and having a vent hole;
A battery comprising: a second sealing lid which is disposed on an outer surface of the exterior member and seals the second opening.   The said resin containing sheet | seat has metal adhesiveness, and the said resin containing sheet | seat is heat-bonded to the edge part of the said 2nd opening part of the said inner surface of the said exterior member. battery.

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