JP2011210690A - Sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for improving productivity in a sealing process by avoiding a sealing failure occurring when sealing a liquid intake port provided on a battery seal, and secure long-term reliability in preventing liquid leakage after fitting.SOLUTION: A sealing plug 21 includes a lid 22 of a flat shape and a plug 23 provided so as to project in a central part of the lid, and includes an annular elastic member 24 between the intake port 20 and the sealing plug 21 arranged so as to cover the intake port. The lid 22 is arranged so as to cover the electrolyte solution intake port of the battery seal 10, and the plug 23 is inserted into the intake port opened on the battery seal through an inner air gap of the annular elastic member 24. By pressure contacting the annular elastic member 24 with the sealing plug formed of a sidewall of the intake port, the lid, and the plug, welding between the sealing plug 21 and the battery seal 10 is sufficiently carried out to securely seal. Therefore, the sealed battery with high reliability can be provided.

Description

The present invention relates to a sealed battery, and more particularly, to a technique for injecting an electrolytic solution from a liquid injection port into a battery outer can and sealing the liquid injection port with a sealing plug after the injection.

In recent years, nickel metal hydride has been used as an electronic device such as a mobile phone and a personal computer, a power source for an uninterruptible power source of a hybrid vehicle, an electric vehicle, a mobile phone base station, and a power storage power source used for power leveling. Secondary batteries and sealed batteries such as non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries are expected.

Normally, a sealed battery has an electrochemical function as a battery only when an electrolyte is injected. As a method for this, there are many methods in which an electrode body is accommodated in an outer can, and then an electrolytic solution is poured into the outer can, and then sealed with a battery seal, but between the battery seal and the outer can opening. When sealing is performed by laser welding, sealing failure is liable to occur due to adhesion of the electrolyte to the place to be welded.

Therefore, a small liquid injection port of about 1 to 3 mm for injecting the electrolyte into the battery sealing body is established, and the opening of the outer can is sealed with the battery sealing body, and then the nozzle from the liquid injection port is used. There is also known a method in which an electrolytic solution is injected, and then a sealing plug is fitted into the injection port and this is sealed by laser welding.

In Patent Document 1, after injecting an electrolyte from an injection hole 13 for injecting an electrolyte formed in the lid plate 2, the sealing plug 3 is inserted into the injection hole 13, and the injection hole is sealed by laser welding. A technique for stopping is disclosed.

Patent Document 2 discloses that a liquid injection port 13 formed in a sealing body 12 includes an elastic sealing portion 21 and a metal plate-like body that holds the sealing portion 21 and is welded to the liquid injection port 13. The technique which can reduce the sealing defect of the liquid injection port 13 by making it the structure which seals the liquid injection port 13 with the liquid port stopper 20 which consists of 25 is disclosed.

Japanese Patent Laid-Open No. 11-25936 JP 2005-190689 A

However, since the plug body portion and the lid body portion of the sealing plug are integrated, when the plug body portion of the sealing plug is press-fitted into the liquid inlet, the external dimensions of the plug body and the opening of the liquid inlet are opened. When the dimensional difference with the diameter is large, the plug is not press-fitted into the liquid injection port, and the sealing plug does not adhere to the battery plug. For this reason, when the sealing plug is welded to the battery sealing body after injecting the electrolytic solution into the sealed battery, there is a problem that a welding failure occurs and productivity is deteriorated. In addition, the fitting range between the plug body and the liquid injection port is narrow, and there are problems such as those that are tight and cannot be fitted, and that the fitting can be made but is loose and leaks. For this reason, welding between the sealing plug and the battery sealing body becomes insufficient, resulting in poor sealing.

The present disclosure improves productivity in a sealing process between a sealing plug used when sealing a liquid injection port established in a sealed battery and a battery sealing body or an outer can provided with the liquid injection port. Further, it is to provide a highly reliable sealed battery that further reduces the leakage failure by increasing the adhesion between the sealing plug and the liquid injection port.

The sealed battery according to the present invention includes an outer can, an electrode group that is housed in the outer can and includes a positive electrode and a negative electrode, a battery sealing body that is attached to an opening of the outer can, and the battery sealing body or the outer packaging. A sealed battery comprising a liquid injection port for injecting an electrolyte into the outer can provided on the can, and a sealing plug for sealing the liquid injection port,
The sealing plug is formed of a lid body fixed in a state of covering the liquid injection port provided in the battery sealing body or the outer can, and a plug body supported by the lid body, A sealed battery comprising an annular elastic member between a liquid port and a sealing plug disposed so as to cover the liquid injection port.

The present invention improves the productivity in the sealing step between a sealing plug used when sealing a liquid injection port established in a sealed battery and a battery sealing body or an outer can having a liquid injection port. Further, by increasing the adhesion between the sealing plug and the liquid inlet, liquid leakage defects can be reduced, and a highly reliable sealed battery can be provided.

The expansion | deployment perspective view which shows the sealed battery of embodiment. The perspective view which shows the sealing part of the sealed battery of embodiment. FIG. 3 is a cross-sectional view taken along a line AA in FIG. The shape figure of the cyclic | annular elastic member in embodiment of this invention. AA sectional view in Drawing 2 by Example 4 of the present invention. FIG. 3 is a cross-sectional view taken along the line AA in FIG.

Hereinafter, a sealed battery according to an embodiment of the present invention will be described with reference to the drawings.

The square sealed battery shown in FIG. 1 includes an outer can 1 having a bottomed rectangular cylindrical shape. The outer can 1 is formed, for example, by deep drawing an aluminum plate or an aluminum alloy plate. The electrode group 2 is formed by, for example, winding a sheet-like positive electrode and a sheet-like negative electrode in a spiral shape with a separator in between, and then crushing the whole into a square shape that matches the cross-sectional shape of the battery can It is produced by doing.

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. As the positive electrode active material, oxides, sulfides, polymers, and the like that can occlude and 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. As the negative electrode active material, metal oxides, metal sulfides, metal nitrides, alloys, and the like that can occlude and release lithium can be used. It is a substance. 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 oxide, 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.

A non-aqueous electrolyte (not shown) is accommodated in the outer can 1 and impregnated in the electrode group 2. The non-aqueous electrolyte is prepared by dissolving an electrolyte (for example, a lithium salt) in a non-aqueous solvent. 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 (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenide (LiAsF6), and lithium trifluoromethanesulfonate (LiCF3SO3). ) And the like. 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.

As shown in FIG. 1, the plurality of positive electrode conductive tabs 3 are electrically connected to a plurality of locations of the positive electrode, and each is led upward from the upper end face of the electrode group 2. On the other hand, the plurality of negative electrode conductive tabs 4 are electrically connected to a plurality of portions of the negative electrode, and each is led upward from the upper end face of the electrode group 2. As the positive electrode conductive tab 3, for example, a positive electrode current collector partially extended can be used, but may be separate from the positive electrode. In addition, the negative electrode conductive tab 4 may be a negative electrode current collector partially extended, for example, but may be separate from the negative electrode.

The positive electrode conductive tab 3 is covered with a positive electrode protection lead 5 in which the outermost layers of both of the overlapped portions are U-shaped or folded in two after at least the tip portions are overlapped. The positive electrode protection lead 5 is fixed to the positive electrode conductive tab 3 by welding. On the other hand, the negative electrode conductive tab 4 is covered with a negative electrode protective lead 6 in which at least the front end portions are overlapped, and the outermost layers of both of the overlapped portions are U-shaped or folded in two. The negative electrode protection lead 6 is fixed to the negative electrode conductive tab 4 by welding. In addition, although methods, such as laser welding, ultrasonic welding, resistance welding, are used for the welding method of a conductive tab and a protection lead, ultrasonic welding is preferable. The material of the positive electrode protection lead 5 can be, for example, aluminum or an aluminum alloy. The material of the negative electrode protection lead 6 can be aluminum or an aluminum alloy, for example. The material of the positive electrode protection lead 5 is preferably the same material as that of the positive electrode conductive tab 3, and the material of the negative electrode protection lead 6 is preferably the same material as that of the negative electrode conductive tab 4.

A square plate-like positive electrode intermediate lead 7 is welded to one surface outside the positive electrode protection lead 5. The positive intermediate lead 7 is desirably larger in size than the area facing the positive electrode protection lead 5, and the thickness is desirably small from the thickness of the positive electrode lead 15. A rectangular plate-like negative electrode intermediate lead 8 is welded to one surface outside the negative electrode protection lead 6. The negative electrode intermediate lead 8 is desirably larger in size than the area facing the negative electrode protection lead 6, and the thickness is desirably small with respect to the thickness of the negative electrode lead 14. As a welding method, laser welding, ultrasonic welding, resistance welding, or the like is used, but ultrasonic welding is preferable. The material of the positive electrode intermediate lead 7 can be, for example, aluminum or an aluminum alloy. The material of the negative electrode intermediate lead 8 can be, for example, aluminum or an aluminum alloy. The material of the positive electrode intermediate lead 7 is preferably the same material as that of the positive electrode conductive tab 3, and the material of the negative electrode intermediate lead 8 is preferably the same material as that of the negative electrode conductive tab 4.

The opening of the outer can 1 is sealed with a sealing member 9. As shown in FIG. 1, the sealing member 9 includes a battery sealing body 10 that closes the opening of the outer can 1, and an output terminal (rivet) 12 that is attached to the outer surface (upper surface) of the battery sealing body 10 via a gasket 11. And a negative electrode lead 14 and a positive electrode lead 15 attached to the inner surface (lower surface) of the battery sealing body 10 via an insulator 13. Examples of the material of the gasket 11 include polypropylene (PP) and thermoplastic fluororesin. Examples of the thermoplastic fluororesin include tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

The battery sealing body 10 is made of a press-molded product made of aluminum or an aluminum alloy plate material. A through hole 16 is formed on the plate surface for attaching the gasket 11, and an opening peripheral edge on the upper surface side of the through hole 16 is formed. A receiving seat 17 for the gasket 11 is formed in a recess. The receiving seat 17 has a shape other than a circle, for example, a quadrangle in FIG. On the other hand, the positive electrode terminal 18 as the electrode terminal protrudes in a convex shape on the upper surface side of the battery sealing body 10. The tip surface of the positive electrode terminal 18 has a shape other than a circle, for example, a quadrangle in FIG. The pressure release valve includes an X-shaped groove 19 provided on the bottom surface in the recess located between the receiving seat 17 and the positive electrode terminal 18 on the upper surface of the battery sealing body 10, and the case internal pressure is constant. If it exceeds, the groove 19 breaks to release the internal pressure. The electrolyte solution injection port 20 is closed by the sealing plug 21 and the elastic annular member 24 after the electrolyte solution is injected. The sealing plug 21 is welded to the battery sealing body 10.

The negative electrode lead 14 is provided so as to communicate with the shaft through hole 30 of the insulator 13, and at least a part of the first plate portion 14 a having a shaft through hole 14 c having a shape other than a circular shape, And a second plate portion 14b extending from the plate portion 14a to the electrode group 2 side, and has an L-shaped cross-sectional shape. The first plate portion and the second plate portion are made of a conductive material. The shaft through hole 14c is a circular hole. The shaft tip 24 of the output terminal 12 is inserted into the shaft through hole 14c. The thickness of the negative electrode lead 14 is desirably 0.5 to 1.5 mm. The material of the negative electrode lead 14 is changed according to the material of the active material. When the negative electrode active material is lithium titanate, aluminum or an aluminum alloy can be used.

The positive electrode lead 15 includes a first plate portion 15a made of a rectangular plate, and a second plate portion 15b extending from the first plate portion 15a to the electrode group 2 side. The first plate portion and the second plate portion are made of a conductive material. Laser welding is performed around the positive electrode terminal 18 in contact with the first plate portion 15 a and the lower surface of the battery sealing body 10. Although the material of the positive electrode lead 15 is changed depending on the type of the positive electrode active material, for example, aluminum or an aluminum alloy can be used.

As shown in FIGS. 1 and 2, the negative electrode intermediate lead 8 is laser welded to the second plate portion 14b of the negative electrode lead 14 of the sealing member 9, and the second plate portion 15b of the positive electrode lead 15 of the sealing member 9 is used. The positive intermediate lead 7 is laser welded. Providing the positive and negative intermediate leads 7 and 8 facilitates electrical connection between the sealing member 9 and the positive and negative electrode conductive tabs 3 and 4 of the electrode group 2. That is, the positive and negative electrode conductive tabs 3 and 4 are sandwiched between the positive and negative electrode protective leads 5 and 6 and the intermediate leads 7 and 8, and these are integrated by ultrasonic welding, and then the intermediate leads 7 and 8 are connected to the positive and negative electrode leads 14 and 15 respectively. By performing laser welding on the sealing member 9, vibration is not applied to the sealing member 9 during welding, so that the breakage of the groove 19 of the pressure release valve provided in the sealing member 9 can be prevented. When the protective lead can be thickened and the conductive tab to which the protective lead is welded can be laser-welded to the lead member, the intermediate lead may not be used.

After electrical connection between the sealing member and the electrode group, the battery sealing body 10 is fitted into the outer can 1 and the fitting surface between the battery sealing body 10 and the outer can 1 is sealed by welding. . Finally, after the electrolyte solution is injected into the outer can 1 from the electrolyte solution injection port 20 of the battery sealing body 10, as shown in FIG. 3A, the plug body 23 of the sealing plug 21 is annular elastic member. The battery shown in FIG. 1 is obtained by inserting into the inner space part 24 of 24, fitting the sealing plug 21 into the liquid inlet 20 and welding it, and sealing the liquid inlet 20.

Next, the sealing member will be described. As shown in FIG. 1, the liquid injection port is a hole having a small diameter of about 1 to 3 mm opened in a battery sealing body that hermetically seals the outer can.

As shown in FIG. 3B, the sealing plug 21 is formed by a flat lid body 22 and a plug body 23 provided so as to protrude from the center of the lid body. Is inserted into the inner space of the annular elastic member 24, and a sealing plug 21 is fitted into the liquid injection port 20 and welded to seal the liquid injection port 20.

The lid body 22 is installed so as to cover the electrolyte solution injection port of the battery sealing body 10, and the plug body 23 is inserted through the inner space of the annular elastic member 24 into the liquid injection port opened in the battery sealing body, The annular elastic member 24 is in pressure contact with a sealing plug formed by a side wall portion of a liquid inlet, a lid body, and a plug body.

It is preferable that the lid body 22 has rigidity capable of holding the plug body 23 press-fitted into the liquid injection port in the liquid injection port. And in order to seal a liquid injection port, it adheres by laser welding etc. Therefore, the material of the lid 22 is preferably the same material as the battery sealing body. Specifically, in this embodiment, aluminum or aluminum alloy that is the same quality as the battery sealing body is suitable.

The plug body may be formed integrally with the lid body or may be fixed to the lid body as a separate part. The material is not particularly limited, but if it is formed integrally with the lid, it will be of the same quality, and if it is formed as a separate part, the side wall portion of the liquid inlet and the sealing plug will be connected via an annular elastic member. In order to maintain the sealing, it is preferable to have rigidity. The plug body is preferably made of a material having an electrolytic solution resistance and a heat resistance in preparation for direct contact with the electrolytic solution or when the battery generates heat due to some external trouble such as overcharge. Specifically, the same material as the lid is suitable.

The annular elastic member 24 is injected into the battery container containing the electrode group from the injection port, and then disposed in the injection port. For this reason, the material which has electrolyte solution resistance and heat resistance is preferable for the case where the annular elastic member is in direct contact with the electrolyte solution or the battery generates heat due to some external trouble such as overcharge. Specifically, EP rubber, EPDM, silicon rubber, polypropylene, polyethylene and the like can be used. In particular, EP rubber and EPDM are preferable.

The shape of the annular elastic member is a ring shape with a circular cross section, as shown in FIG. In the sealing plug combined with the annular elastic member, the length of the collar portion extending outward from the outer shape of the lid body of the sealing plug is set longer than the diameter of the ring-shaped portion of the annular elastic member. The It is preferable that the length of the collar portion extending outward from the outer shape of the lid body of the sealing plug is twice or more the diameter of the ring-shaped portion of the annular elastic member. However, the size of the lid of the sealing plug is not particularly limited as long as it does not protrude from the outer shape of the sealing member of the sealed battery.

The ring-shaped annular elastic member having a circular cross section shown in FIG. 4A has been described. However, as shown in FIGS. 4B to 4C, the cross-sectional shape is an oval or a polygon such as a hexagon. You can also.

(Example 1)
As the outer can 1, a rectangular outer can having a length of 20 mm, a width of 100 mm, a height of 110 mm, and a can wall thickness of 0.5 mm formed by drawing an aluminum plate was used. Next, a positive electrode plate prepared by applying LiCoO2 as a positive active material to a strip-shaped current collector as a positive electrode, and lithium titanate having a spinel structure represented by Li4 + xTi5O12 (x is -1≤x≤3) as a negative electrode Electrode group 2 is formed by winding a negative electrode plate formed by applying a main active material to a strip-shaped current collector through a separator, and a positive electrode tab 3 and a positive electrode terminal 18 extending from electrode group 2 are formed. Welding is performed via the positive electrode protection lead 5, the positive electrode intermediate lead 7, and the positive electrode lead 15. Similarly, one negative electrode tab 4 and the negative electrode terminal 12 are welded via the negative electrode protection lead 6, the negative electrode intermediate lead 8, and the negative electrode lead 14. After that, the electrode group 2 was inserted into the outer can 1, the battery sealing body 10 was fitted into the outer can opening, and the fitting portion was integrated by laser welding.

As a non-aqueous electrolyte, 1.5 mol / L of lithium salt LiBF4 was mixed with an organic solvent in which ethylene carbonate (EC) and γ-butyrolactone (GBL) were mixed at a volume ratio (EC: GBL) of 1: 2. After dissolving, preparing a liquid non-aqueous electrolyte (non-aqueous electrolyte), placing the battery semi-product obtained as described above under reduced pressure, and pouring this non-aqueous electrolyte from the electrolyte injection port 20, After closing the liquid injection port with the sealing plug 21, the periphery of the sealing plug 21 is laser welded and welded to the battery sealing body 10, so that the sealing is performed with a length of 20 mm, a width of 100 mm, a height of 110 mm, and a capacity of 6000 mAh. Type prismatic lithium ion secondary battery was fabricated.

As shown in FIGS. 3A to 3B, the sealing plug 21 is formed by a flat lid body 22 and a plug body 23 that protrudes from the center of the lid body.

The lid body 22 is installed so as to cover the electrolyte solution injection port of the sealed battery seal body 10, and the plug body 23 is inserted into the liquid injection port opened in the battery seal body through the inner space of the annular elastic member 24. The annular elastic member 24 is pressed against a sealing plug formed by a side wall portion of the liquid injection port, a lid body, and a plug body.

The sealing plug 21 has an overall height of 2.5 mm, a lid diameter of 8 mm, a lid plate thickness of 0.3 mm, an outer diameter of the distal end portion 23 a of the plug body of 2.1 mm, and an outer portion of the root portion 23 b. The diameter was 2.4 mm, the outer diameter of the annular elastic member 24 was 3 mm, the inner diameter was 2.2 mm, the cross-sectional shape of the ring-shaped part was circular, and the diameter of the circular part was 0.4 mm. In this case, the annular elastic member 24 is made of rubber (for example, EP rubber) in order to give elasticity. The sealing plug 21 is made of aluminum which is the same as the material of the outer can 1.

(Example 2)
As shown in FIG. 4B, the annular elastic member has an elliptical cross-sectional shape, the outer diameter of the annular elastic member 25 is 3 mm, the inner diameter is 2.2 mm, and the major axis of the elliptical cross-section is 0.6 mm. A sealed battery having the same configuration as in Example 1 was produced except that the minor axis was changed to 0.4 mm.

(Example 3)
As shown in FIG. 4 (c), the annular elastic member has a hexagonal cross section, and the annular elastic member 26 has an outer diameter of 3 mm and an inner diameter of 2.2 mm. A sealed battery having the same configuration as in Example 1 was produced except that the thickness was changed to 0.25 mm.

Example 4
As shown in FIG. 5, the sealing plug 31 is formed of an elastic rubber plug 33 and a metal lid 32 that holds the plug 33 and is welded to the battery sealing body 10. The plug body is solid resin, and the plug body 33 is bonded to the metal lid body 32, so that the base section has a predetermined area and is formed on the tip section so as to taper from the base section. The shape of the truncated cone was the same as that of Example 1. Further, the lid 32 is made of aluminum which is the same as the material of the outer can 1. In order to bond the plug 33 to the lid 32, first, a polyolefin-based adhesive is applied to the lid 32 by screen printing or the like, and this is put in a vulcanization mold and placed on the lid 22. The plug 23 is formed by vulcanizing rubber. A sealed battery having the same configuration as in Example 1 was produced except that the sealing plug 31 was used.

(Comparative Example 1)
As shown in FIG. 6, a sealed battery having the same configuration as that of Example 1 except that the sealing plug is formed of a lid 42 and a plug 43 having a solid shape filled with resin. Produced.

About the said Example and comparative example, the battery was manufactured with the manufacturing equipment of a sealed battery, and the sealing plug supply state in that case was confirmed. A battery sealing body is fitted into the opening of the outer can, and the battery semi-finished product integrated by laser welding of the fitting part is placed under reduced pressure. After pouring a non-aqueous electrolyte from the electrolyte inlet, After the liquid port was closed with a sealing plug, the periphery of the sealing plug was laser welded to complete a sealed battery. In the process of welding the sealing plug to the battery sealing body, the sealing plug is pressed into the injection port and the contact state between the lid and the battery sealing body is observed for 10,000 batteries, and the sealing plug is floated. And those that were not press-fitted into the injection port were regarded as defective.

Next, a leak test was performed on 3000 completed sealed batteries, and the sealing performance of the batteries was evaluated. The leak test is a high-temperature, high-humidity storage test in which the completed sealed battery is stored in a high-temperature, high-humidity tank with a temperature of 60 ° C. and a humidity of 90% Rh for 3 months. Check and evaluate whether there is any leakage failure such as liquid scooping. When the lid and the battery sealing body are welded to each other after the electrolyte is injected, the electrolyte injected into the battery is not welded when the lid and the battery sealing body are laser-welded. It is vaporized by the heat generated by laser welding, creating small pinholes or blowholes that cannot be visually confirmed from the inside of the battery to the outside of the battery at the welded portion. Table 1 summarizes the defect rates of the above-described process defects and leak defects.

As is clear from Table 1, in the battery of the example, the leak failure rate and the sealing plug supply process failure rate are significantly reduced as compared with the battery of the comparative example. The low leak rate in the battery of the example indicates that the occurrence of poor sealing between the liquid injection port 20 and the sealing plug 21 is small. In particular, by using an annular elastic member, even when the joining position of the lid body and the plug body is shifted, the plug body is sufficiently pressed into the liquid injection port, and the adhesion between the lid body and the battery sealing body is ensured. By doing so, welding between the sealing plug and the battery sealing body is sufficiently performed, and the sealing can be surely performed.

The sealing plug supply failure rate in the comparative example is high because when the sealing plug 21 is continuously supplied, the joining position of the lid of the sealing plug and the plug is shifted from the center of the lid. Due to variations in body external dimensions and liquid inlet inner diameter, the fitting range between the stopper and the liquid inlet is narrow, and the fitting range is tight and cannot be fitted. What cannot be secured is the cause of supply failure.

On the other hand, the sealing plug supply failure rate in the examples is low when the sealing plug is press-fitted into the liquid injection port, even when the joining position of the lid body and the plug body is shifted. This is because the annular elastic member is in close contact with the body, and the liquid injection port is sealed by the sealing plug.

As described above, in this embodiment, the sealing plug used when sealing the liquid injection port established in the battery sealing body for a sealed battery is fixed on the surface of the battery sealing body in a state of covering the liquid injection port. The plug body is composed of a lid body and a plug body, and the plug body is inserted into the liquid injection port opened in the battery sealing body through the inner space of the annular elastic member.

The annular elastic member is pressed against a sealing plug formed by a side wall portion of the liquid injection port, a lid body, and a plug body.

When the liquid injection port is sealed in this way, the sealing plug and the inner wall of the liquid injection port of the battery sealing body can be sealed by the annular elastic member, and the lid body and the battery sealing body arranged on the plug body Airtightness can be ensured before laser welding.

When the annular elastic member is disposed between the sealing plug and the liquid injection port of the battery sealing body, the joining position of the sealing plug lid body and the plug body is shifted from the center position of the lid body. In addition, since the plug body is sufficiently inserted into the liquid injection port at a constant pressure by the annular elastic member, the plug body and the inner wall of the electrolyte liquid injection port are in close contact with each other through the ring elastic member, so that the sealing is performed. The stopper plug comes into close contact with the battery sealing body, and the sealing stopper and the battery sealing body are sufficiently welded. The sealed battery thus manufactured has no leakage and can ensure long-term reliability.

In other words, according to the present embodiment, it is possible to provide a highly reliable sealed battery by reducing the sealing plug insertion failure and reducing the leakage due to the increased adhesion. For this reason, it is possible to provide a sealed battery excellent in reliability with no liquid leakage in heat cycle, large current applications, etc., and is particularly used for in-vehicle secondary batteries mounted on hybrid cars and electric cars, and power leveling. This is suitable as a secondary battery for power storage.

The above-described embodiment is not limited to the above-described embodiment, and the constituent elements can be modified and embodied without departing from the spirit 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.

DESCRIPTION OF SYMBOLS 1 ... Exterior can, 2 ... Electrode group, 3 ... Positive electrode conductive tab, 4 ... Negative electrode conductive tab, 5 ... Positive electrode protective lead, 6 ... Negative electrode protective lead, 7 ... Positive electrode intermediate lead, 8 ... Negative electrode intermediate lead, 9 ... Sealing member DESCRIPTION OF SYMBOLS 10 ... Battery sealing body, 11 ... Gasket, 12 ... Output terminal, 13 ... Insulator, 14 ... Negative electrode lead, 15 ... Positive electrode lead, 16 ... Through-hole, 17 ... Receiving seat, 18 ... Positive electrode terminal, 19 ... Pressure release Valve, 20 ... Electrolyte injection port, 21, 31, 41 ... Sealing plug, 22, 32, 42 ... Lid, 23, 33, 43 ... Plug, 24 ... Ring elastic member

Claims (4)

An outer can, an electrode group housed in the outer can and including a positive electrode and a negative electrode, a battery sealing body attached to an opening of the outer can, and the outer casing provided in the battery sealing body or the outer can A sealed battery comprising a liquid injection port for injecting an electrolyte solution therein and a sealing plug for sealing the liquid injection port,
The sealing plug is formed of a lid body fixed in a state of covering the liquid injection port provided in the battery sealing body or the outer can, and a plug body supported by the lid body, A sealed battery comprising an annular elastic member between a liquid port and the sealing plug disposed so as to cover the liquid injection port. The annular elastic member is formed in a state in which the plug body of the sealing plug is press-fitted into the annular inner space of the annular elastic member, and the outer side of the annular elastic member is in close contact with the inner side wall portion of the liquid injection port The sealed battery according to claim 1, wherein the sealed battery is sealed. The sealed battery according to claim 1, wherein the annular elastic member is sealed without being in contact with the lid of the sealing plug. 2. The sealed battery according to claim 1, wherein the annular member has a circular, oval or polygonal cross-sectional shape.

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