JP7023144B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

The present invention relates to a non-aqueous electrolyte secondary battery.

The non-aqueous electrolyte secondary battery is used in a power supply unit of an electronic device, a power storage unit that absorbs fluctuations in the amount of power generated by a power generation device, and the like. In particular, small non-aqueous electrolyte secondary batteries such as coin type (button type) have traditionally been used as backup power supplies for clock functions, backup power supplies for semiconductor memories, backup power supplies for electronic devices such as microcomputers and IC memories, and solars. In addition to watch batteries, it is widely used in portable devices such as power supplies for driving motors.
Such a coin-type non-aqueous electrolyte secondary battery adopts, for example, a structure in which a positive electrode, a negative electrode, and an electrolyte are housed in a storage space surrounded by a bottomed cylindrical positive electrode can and a negative electrode can. The positive electrode is electrically connected to the can, and the negative electrode is electrically connected to the negative electrode can.
Further, a gasket is interposed between the positive electrode can and the negative electrode can, and the positive electrode can and the negative electrode can are caulked to seal the can, and the accommodation space of the non-aqueous electrolyte secondary battery is sealed.

In this kind of coin-type non-aqueous electrolyte secondary battery, in order to increase the capacity, it is necessary to increase the battery height and increase the volumes of the positive electrode and the negative electrode.
Further, when the height of a coin-type battery that can be reflow-mounted is increased, the internal pressure of the battery may increase due to the influence of heat during reflow mounting, and the gasket may be deformed.

As disclosed in Patent Document 1 below as a structure that can withstand an increase in the internal pressure of a battery and can prevent deformation of the gasket, a cup-shaped inner battery case having a flange plate on the bottom side of the positive electrode case of the battery. The structure provided with the above is known. In the structure described in Patent Document 1, a reinforcing rib is provided on the side surface of the battery inner case to reinforce the flange plate, and the bottom of the gasket is supported by the flange plate to prevent deformation of the gasket, resulting in a stable sealing state for a long period of time. Is getting.
Further, Patent Document 2 below discloses a structure in which a reverse hat type positive electrode ring is interposed between the positive electrode case and the positive electrode, and the bottom portion of the gasket is supported by the flange plate-shaped circumferential portion of the positive electrode ring. There is.

Japanese Unexamined Patent Publication No. 2011-129253 Japanese Unexamined Patent Publication No. 2007-200593

In the techniques described in Patent Documents 1 and 2, a flange plate of a cup-shaped battery inner case is used, or a gasket is supported by the circumference of an inverted hat type positive electrode ring. Since the portion that supports the gasket is made of a plate material, there is a problem that the supporting portion is easily deformed. For example, when the opening of the positive electrode case is pressed toward the gasket side for sealing by caulking, the pressure associated with the caulking acts on the flange plate and the circumferential portion via the gasket, which may be deformed.
Deformation of the flange plate or the circumferential portion that supports the gasket may result in deformation of the gasket or deformation of the battery case, resulting in a decrease in liquid leakage resistance.

In order to improve the liquid resistance, it is necessary to increase the wall thickness of the flange plate and the circumferential portion to improve the strength of the gasket support portion. However, if the wall thickness of the battery inner case or the wall thickness of the entire reverse hat type positive electrode ring is increased, the wall thickness of the battery inner case bottom plate and the wall thickness of the bottom plate of the reverse hat type positive electrode ring also increase. As a result of limiting the height of the positive electrode or the thickness of the electrode that can be accommodated inside, there may be a problem that the capacity of the battery cannot be sufficiently increased. In addition, since the positive electrode is electrically connected to the positive electrode can, the bottom plate of the battery inner case or the bottom plate of the inverted hat type positive electrode ring is interposed between the positive electrode and the electrode can body, and the internal resistance of the battery increases. There is also a risk of doing so.

The present invention has been made in view of the conventional circumstances described above, and is a high-capacity type capable of realizing a highly durable sealing structure even under the influence of heat such as during reflow mounting and improving liquid leakage resistance. The purpose is to provide a non-aqueous electrolyte secondary battery.

"1" In order to solve the above problems, the non-aqueous electrolyte secondary battery according to one embodiment of the present invention is fixed with a bottomed cylindrical positive electrode can and a gasket inside the opening of the positive electrode can. A negative electrode can that forms an accommodation space between the positive electrode can and a negative electrode can is provided, and the accommodation space is sealed by providing a caulking portion that crimps the opening of the positive electrode can to the negative electrode can side. A non-aqueous electrolyte secondary battery containing a negative electrode, an electrolytic solution, and a separator, and a spacer having a ring portion located between the bottom surface of the gasket and the inner bottom surface of the positive electrode can on the inner bottom side of the positive electrode can. The outer peripheral surface of the ring portion is brought into contact with the inner peripheral surface on the bottom side of the positive electrode can, the bottom surface thereof is brought into contact with the inner bottom surface of the positive electrode can, and the upper surface thereof is substantially the entire surface of the bottom surface of the gasket. It is characterized in that it is formed in a thick annular shape to be brought into contact with.

Since the ring portion of the spacer of this embodiment is located between the bottom surface of the gasket and the bottom surface of the positive electrode can, the ring portion is deformed even if the caulking force when caulking the peripheral edge of the opening of the positive electrode can acts. Supports the bottom of the separator without any. Therefore, the sealing structure of the positive electrode can, the negative electrode can, and the gasket by caulking can be formed into a reliable sealing structure having the desired shape without deformation or distortion. Further, even if the height of the positive electrode can is increased due to the increase in capacity, it can be dealt with by increasing the thickness of the ring portion according to the height of the positive electrode can.
For this reason, according to this embodiment, the structure is highly durable and has improved liquid leakage resistance even if it is affected by heat such as when reflowing, and the structure is sealed via a gasket by the caulking part. It has the effect of providing batteries.
A thick annular ring in which the outer peripheral surface of the ring portion is in contact with the inner peripheral surface on the bottom side of the positive electrode can, the bottom surface of the ring portion is in contact with the inner bottom surface of the positive electrode can, and the upper surface of the ring portion is in contact with almost the entire bottom surface of the gasket. In the case of the configuration formed in the above, the ring portion is stably supported on the inner bottom portion side of the positive electrode can without any gap, so that the ring portion that is stably supported during the caulking process stably supports the gasket bottom portion. Therefore, it is possible to obtain a sealing structure having a desired shape without unnecessary deformation or distortion during caulking.

"2" In the non-aqueous electrolyte secondary battery of the above embodiment, the outer edge of the gasket is in close contact with the outer peripheral surface of the side wall opening end of the negative electrode can, and the inner edge of the gasket is in close contact with the inner peripheral surface of the side wall opening end of the negative electrode can. A configuration can be adopted in which the portion and the bottom wall portion that is in close contact with the side wall opening end of the negative electrode can and connects the outer edge portion and the inner edge portion are provided, and the ring portion is in contact with the bottom wall portion.
"3" In the non-aqueous electrolyte secondary battery of the one form, the configuration in which the ring portion is composed of a laminated body of a plurality of auxiliary rings can be adopted.

Since the gasket can be supported by constructing the ring from the laminated body of the auxiliary ring, the sealing structure of the positive electrode can, the negative electrode can and the gasket by caulking is formed into a reliable sealing structure as intended without deformation or distortion. can.
Further, even if the height of the positive electrode can is increased due to the increase in capacity, it can be easily dealt with by adjusting the number of laminated auxiliary rings and increasing the thickness of the ring portion according to the height of the positive electrode can.

"4" In the non-aqueous electrolyte secondary battery of the one embodiment, a configuration in which the positive electrode is arranged inside the ring portion can be adopted.

When the ring portion is in contact with the bottom wall portion of the gasket having the outer edge portion, the inner edge portion, and the bottom wall portion, the ring portion surely supports the gasket bottom portion and is sandwiched between the outer edge portion and the inner edge portion to reach the bottom. Including the outer peripheral edge of the negative electrode can body located on the wall part, these can be securely supported by the ring part during caulking, and a sealing structure with the desired shape without unnecessary deformation or distortion can be obtained. can.

When the positive electrode is arranged inside the ring portion, the positive electrode current collector provided on the positive electrode side can be easily connected to the inner bottom surface of the positive electrode can, and the internal resistance does not increase unnecessarily. A water electrolyte secondary battery can be provided. In addition, the electrical connection between the positive electrode and the positive electrode can can be easily performed.

According to this embodiment, since the ring portion located between the bottom surface of the gasket and the bottom surface of the positive electrode can is provided, the ring portion is deformed even if the caulking force when caulking the peripheral edge of the opening of the positive electrode can acts. Support the bottom of the separator without doing anything. Therefore, the sealing structure of the positive electrode can, the negative electrode can, and the gasket by caulking has a desired shape without unnecessary deformation and distortion, and can be formed as a reliable sealing structure. Further, even if the height of the positive electrode can is increased due to the increase in capacity, it can be dealt with by increasing the thickness of the ring portion according to the height of the positive electrode can.
For this reason, according to this embodiment, the structure is highly durable and has improved liquid leakage resistance even if it is affected by heat such as when reflowing, and the structure is sealed via a gasket by the caulking part. It has the effect of providing batteries.

It is sectional drawing which shows the non-aqueous electrolyte secondary battery before caulking processing which concerns on 1st Embodiment. It is sectional drawing which shows the non-aqueous electrolyte secondary battery after caulking processing which concerns on 1st Embodiment. It is sectional drawing which shows the non-aqueous electrolyte secondary battery before caulking processing which concerns on 2nd Embodiment. It is sectional drawing which shows an example of the conventional non-aqueous electrolyte secondary battery.

Hereinafter, an example of the non-aqueous electrolyte secondary battery according to the embodiment of the present invention will be given, and the configuration thereof will be described in detail with reference to FIGS. 1 and 2. The non-aqueous electrolyte secondary battery described in the present invention is specifically a non-aqueous electrolyte secondary battery in which an active material used as a positive electrode or a negative electrode and an electrolytic solution are housed in a container. Further, in the drawings used in the following description, in order to make each member a recognizable size, the scale of each member is appropriately changed and displayed, so that the relative size of each member is limited to the form shown in the drawing. Of course not.

[First Embodiment of Non-Water Electrolyte Secondary Battery]
The non-aqueous electrolyte secondary battery 1 of the present embodiment shown in FIGS. 1 and 2 is a so-called coin (button) type battery. The non-aqueous electrolyte secondary battery 1 is arranged in the storage container 2 between the positive electrode 10 capable of occluding / discharging lithium ions, the negative electrode 20 capable of occluding / discharging lithium ions, and the positive electrode 10 and the negative electrode 20. The separator 30 is provided with an electrolytic solution 50 containing at least a supporting salt and an organic solvent, and a ring-shaped spacer 15. Note that FIG. 1 shows a state before crimping the opening of the positive electrode can 12, and FIG. 2 shows a state after crimping the opening of the positive electrode can 12.
More specifically, the non-aqueous electrolyte secondary battery 1 is fixed to the bottomed cylindrical positive electrode can 12 via the gasket 40 at the opening 12a of the positive electrode can 12 to provide a storage space between the positive electrode can 12 and the positive electrode can 12. It has a covered cylindrical (hat-shaped) negative electrode can 22 to be formed, and the accommodation space is sealed by crimping the peripheral edge portion 12b of the opening of the positive electrode can 12 shown in FIG. 1 to the inside, that is, to the negative electrode can 22 side. A storage container 2 is provided.

In the storage space sealed by the storage container 2, the positive electrode 10 provided on the inner bottom surface side of the positive electrode can 12 and the negative electrode 20 provided on the negative electrode can 22 side are vertically opposed to each other via the separator 30, and further electrolyzed. The spacer 15 is arranged so as to be filled with the liquid 50 and occupy the bottom of the accommodation space.
As shown in FIG. 1, the gasket 40 is narrowed along the inner peripheral surface of the positive electrode can 12 and is connected to the outer periphery of the separator 30 to hold the separator 30.
Further, the positive electrode 10, the negative electrode 20, and the separator 30 shown in FIG. 2 are impregnated with the electrolytic solution 50 filled in the storage container 2.

In the non-aqueous electrolyte secondary battery 1 shown in FIGS. 1 and 2, a positive electrode 10 is installed on the center of the bottom surface of the positive electrode can 12, and a separator 30 and a negative electrode 20 having a two-layer structure are sequentially arranged on the positive electrode 10.
Although the positive electrode 10 is abbreviated as a single-layer structure in FIGS. 1 and 2, the positive electrode 10 adopts a structure in which a positive electrode active material is laminated on a positive electrode current collector, and the positive electrode current collector is used as a positive electrode can 12. It is electrically connected.
The negative electrode 20 is abbreviated as a two-layer structure in FIGS. 1 and 2, but a structure in which a negative electrode active material is laminated on a negative electrode current collector is adopted, and the negative electrode current collector is electrically attached to the negative electrode can 22. It is connected.

In the present embodiment, the non-aqueous electrolyte secondary battery provided with the positive electrode current collector and the negative electrode current collector is described as an example, but the present invention is not limited to this, and for example, the positive electrode can 12 may be used. A configuration in which the negative electrode can 22 also serves as the negative electrode current collector may be adopted as well as the positive electrode current collector. Further, a structure in which a lithium foil or the like is interposed at the interface between the negative electrode 20 and the separator 30 may be adopted.

The non-aqueous electrolyte secondary battery 1 of the present embodiment is roughly configured as described above, so that lithium ions move from one of the positive electrode 10 and the negative electrode 20 to the other, thereby accumulating (charging) electric charges. , Can release (discharge) electric charge.

(Positive electrode can and negative electrode can)
In the present embodiment, the positive electrode can 12 constituting the storage container 2 is configured in a bottomed cylindrical shape as described above, and has a circular opening 12a in a plan view. As the material of such a positive electrode can 12, conventionally known materials can be used without any limitation, and for example, stainless steels such as SUS316L, SUS329J4L, and NAS64 can be adopted.

Further, as described above, the negative electrode can 22 is configured to have a covered cylindrical shape (hat shape), and the outer peripheral end portion 22a thereof is configured to slightly enter the positive electrode can 12 from the opening 12a. As the material of such a negative electrode can 22, conventionally known stainless steel can be adopted as in the material of the positive electrode can 12, and for example, SUS316L, SUS329J4L, SUS304-BA and the like can be used. Further, as the negative electrode can 22, for example, a clad material formed by pressing copper, nickel, or the like onto stainless steel can be used.

As shown in FIG. 2, the positive electrode can 12 and the negative electrode can 22 are formed by caulking the peripheral edge of the opening 12a of the positive electrode can 12 toward the negative electrode can 22 with the gasket 40 interposed therebetween. The non-aqueous electrolyte secondary battery 1 in a state of being sealed and forming a storage space has a sealed structure. Therefore, the maximum inner diameter of the positive electrode can 12 is larger than the maximum outer diameter of the negative electrode can 22.

When the non-aqueous electrolyte secondary battery 1 is a high-capacity type having a diameter d of about 4.0 to 6.0 mm and a height h1 of about 2.1 to 2.8 mm, the positive electrode can 12 and the negative electrode can 22 The plate thickness of the metal plate material used in the above is generally about 0.1 to 0.3 mm, and for example, the average plate thickness of the entire positive electrode can 12 and the negative electrode can 22 can be about 0.15 mm.

(gasket)
As shown in FIGS. 1 and 2, the gasket 40 is formed in an annular shape along the inner peripheral surface of the positive electrode can 12, and the outer peripheral end portion 22a of the negative electrode can 22 is arranged inside the annular groove 41. ..
The gasket 40 has a ring-shaped outer edge portion 40A having an outer diameter that is inserted without a gap on the inner peripheral side of the opening of the positive electrode can 12, a ring-shaped inner edge portion 40B, and the lower ends of the outer edge portion 40A and the inner edge portion 40B. It is composed of a bottom wall portion 40C to which the above is connected. Therefore, an annular groove 41 into which the outer peripheral end portion 22a of the negative electrode can 22 can be inserted is formed on the upper surface side of the outer peripheral edge of the gasket 40.
FIG. 1 shows a state before the opening 12a of the positive electrode can 12 is crimped. From the state of FIG. 1, the peripheral edge 12b of the opening is crimped and the peripheral edge 12b of the opening is squeezed inward. Therefore, the upper edge portion of the outer edge portion 40A of the gasket 40 is pressed against the outer peripheral portion of the negative electrode can 22, and the storage container 2 is sealed.

Further, the gasket 40 is preferably made of, for example, a resin having a heat distortion temperature of 230 ° C. or higher. If the thermal deformation temperature of the resin material used for the gasket 40 is 230 ° C. or higher, heat is generated when the non-aqueous electrolyte secondary battery 1 is used or stored in a high temperature environment, or when the non-aqueous electrolyte secondary battery 1 is used. Even when the above occurs, it is possible to prevent the gasket from being significantly deformed and the electrolytic solution 50 from leaking out.

Examples of the material of the gasket 40 include polypropylene resin (PP), polyphenylsulfide (PPS), polyethylene terephthalate (PET), polyamide, liquid crystal polymer (LCP), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin. (PFA), polyetheretherketone resin (PEEK), polyethernitrile resin (PEN), polyetherketone resin (PEK), polyallylate resin, polybutylene terephthalate resin (PBT), polycyclohexanedimethylene terephthalate resin, polyether Examples thereof include resins such as sulfone resin (PES), polyaminobismaleimide resin, polyetherimide resin, and fluororesin. Among these, it is preferable to use polypropylene resin for the gasket 40 from the viewpoint of preventing the gasket from being significantly deformed during use and storage in a high temperature environment and further improving the sealing performance of the non-aqueous electrolyte secondary battery.

Further, as the gasket 40, a gasket obtained by adding fine powder of glass fiber, mica, whiskers, ceramic or the like to the resin in an addition amount of 30% by mass or less can be preferably used. By using such a material, the gasket is not significantly deformed even by a high temperature, and the electrolytic solution 50 can be prevented from leaking.
Further, a sealing agent may be applied to the inner surface of the annular groove 41 of the gasket 40. As such a sealing agent, asphalt, epoxy resin, polyamide resin, butyl rubber adhesive and the like can be used. Further, the sealing agent can be used after being applied to the inside of the annular groove 41 and then dried.

(Separator)
The separator 30 is interposed between the positive electrode 10 and the negative electrode 20, and an insulating film having a large ion transmittance, excellent heat resistance, and a predetermined mechanical strength is used.
As the separator 30, conventionally used as a separator for a non-aqueous electrolyte secondary battery, a material made of a material satisfying the above characteristics can be applied without any limitation, for example, alkali glass, borosilicate glass, quartz glass, lead glass and the like. Non-woven fabric made of resin such as glass, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyamideimide (PAI), polyamide, polyimide (PI), aramid, cellulose, fluororesin, ceramics, etc. Examples include fiber. Among the above, it is more preferable to use a non-woven fabric made of glass fiber as the separator 30.
Since the glass fiber has excellent mechanical strength and a large ion permeability, it is possible to reduce the internal resistance and improve the discharge capacity.
The thickness of the separator 30 is determined in consideration of the size of the non-aqueous electrolyte secondary battery 1, the material of the separator 30, and the like, and can be, for example, about 5 to 300 μm.

(spacer)
In the structures shown in FIGS. 1 and 2, a ring-shaped spacer 15 is installed on the inner bottom side of the positive electrode can 12.
The spacer 15 has an outer diameter that can be inserted into the inner bottom portion of the positive electrode can 12 without a gap, and has a thick ring-shaped ring having an upper surface 15a that can contact almost the entire surface of the bottom surface 40a of the gasket 40 and support the gasket 40. It consists of a part 15A.
Since the spacer 15 can be inserted into the inner bottom of the positive electrode can 12 without a gap, the outer peripheral surface 15b of the spacer 15 is in contact with the inner peripheral surface of the bottom of the positive electrode can 12, and the bottom surface 15c of the spacer 15 is on the inner bottom surface of the positive electrode can 12. I'm in contact. The inner diameter of the spacer 15 is formed to be slightly larger than the outer diameter of the positive electrode 10, and the positive electrode 10 is arranged inside the spacer 15. Since the outer diameter and inner diameter of the spacer 15 are the above-mentioned sizes, the spacer 15 is formed to occupy the space between the bottom surface 40a of the gasket 40 and the inner bottom surface of the positive electrode can 12.
Since the thickness of the spacer 15 (the thickness in the vertical direction of the spacer 1 when installed horizontally as shown in FIGS. 1 and 2) is slightly smaller than the thickness of the positive electrode 10, the upper surface 15a of the spacer 15 is a separator. It is located slightly below 30.

In the structure of the embodiment shown in FIGS. 1 and 2, the outer peripheral end portion 22a of the negative electrode can 22 extends to a position equivalent to the height of the separator 30. Therefore, the bottom surface 40a of the gasket 40 is arranged at a height of about half the height of the peripheral wall 12A of the positive electrode can 12. Therefore, the thickness of the spacer 1 is formed to be about half the height of the peripheral wall 12A of the positive electrode can 12.

The spacer 15 is preferably made of a hard engineering plastic such as polyetheretherketone resin (PEEK) or polyphenylsulfide (PPS), which is excellent in strength and heat resistance, or a metal material such as stainless steel or aluminum.
When the spacer 15 is made of engineering plastic, the spacer 15 can secure good adhesion to the positive electrode 10, the positive electrode can 12, and the gasket 40, and can improve the sealing performance of the storage container 2.
When the spacer 15 is made of metal, the spacer 15 can improve the sealing property of the container 2 and at the same time increase the durability of the sealing structure. The portion of the spacer 15 in contact with the inner bottom corner portion of the positive electrode can 12 is chamfered according to the R shape of the corner portion of the inner bottom surface of the positive electrode can 12 to ensure adhesion to the inner bottom surface of the positive electrode can 12. Is preferable.
As an example, the size of the spacer 15 is about 4.5 mm in outer circumference, 3.3 mm in inner circumference, and 1.1 mm in height in a button type battery having a diameter of 4.75 mm × t2.55 mm.
The inner diameter of the spacer 15 may be formed to be substantially the same as the outer diameter of the positive electrode 10, or the positive electrode 10 may be embedded inside the spacer 15 without a gap.

(Electrolytic solution)
As the non-aqueous electrolyte secondary battery 1 of the present embodiment, a battery containing at least an organic solvent and a supporting salt is used as the electrolytic solution 50. The electrolytic solution 50 is preferably a high boiling point type organic solvent having reflow heat resistance. For example, the solvent may be a mixed solvent of TEG (tetraethylene glycol dimethyl ether) + DEE (ethylene glycol dimethyl ether), or a mixed solvent in which EC (ethylene carbonate) or VC (vinylene carbonate) is added to TEG instead of DEE. can.
Such an electrolytic solution usually consists of a supporting salt dissolved in a non-aqueous solvent such as an organic solvent, and its characteristics are determined in consideration of the heat resistance and viscosity required for the electrolytic solution.

(Positive electrode)
The type of the positive electrode active material in the positive electrode 10 is not particularly limited, and a positive electrode active material that contains a lithium compound and is conventionally known in this field is used, and further, polyacrylic acid is used as a binder, graphite and the like are used as a conductive auxiliary agent. A mixture can be used. In particular, it contains at least one of lithium manganese oxide (Li ₄ Mn ₅ O ₁₂ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ), MoO ₃ , LiFePO ₄ , and Nb ₂ O ₃ as the positive electrode active material. Of these, lithium-manganese oxide or lithium titanate is more preferably contained.
In the present embodiment, the positive electrode active material may contain not only one of the above materials but also a plurality of the above materials.
Further, the positive electrode 10 may contain a positive electrode conductive auxiliary agent made of a carbonaceous material such as Ketjen black, or may contain a positive electrode binder such as polyacrylic acid.
As the positive electrode current collector, a conductive resin adhesive or the like using carbon as a conductive filler can be used, but conventionally known positive electrode current collectors can be widely applied.

(Negative electrode)
The type of the negative electrode active material in the negative electrode 20 is not particularly limited, but for example, an alloy-based negative electrode such as carbon or Li—Al, or a negative electrode active material conventionally known in this field such as silicon oxide is used, and more appropriate. A mixture of a binder, polyacrylic acid as a binder, and graphite or the like as a conductive auxiliary agent can be used. In particular, it is preferable that the negative electrode active material contains at least one of SiO, SiO ₂ , Si, WO ₂ , WO ₃ and a Li—Al alloy.
The negative electrode current collector can be configured by using the same material as the positive electrode current collector.

In the non-aqueous electrolyte secondary battery 1 configured as described above, as shown in FIG. 1, a spacer 15 is arranged at the bottom of the positive electrode can 12 in a state before the positive electrode can 12 is caulked, and further, the positive electrode 10 and the positive electrode 10 The separator 30 and the negative electrode 20 are arranged, the gasket 40 and the negative electrode can 22 are arranged, and the electrolytic solution 50 is filled. After that, the peripheral portion 12b of the opening of the positive electrode can 12 is squeezed by caulking to form the opening 12a, and the storage container 2 can be sealed.

Here, when caulking is performed, the gasket 40 and the outer peripheral end portion 22a of the negative electrode can 22 are pressed downward by the application of the caulking force, but the upper surface 15a of the spacer 15 supports the bottom surface 40a of the gasket 40. As a result of the gasket 40 being deformed into the desired shape shown in FIG. 2 and intervening between the peripheral edge of the opening of the positive electrode can 12 and the outer peripheral end 22a of the negative electrode can 22, the gasket 40 is excellent in shape without distortion or defects. It is possible to realize a sealing structure.
Therefore, according to this embodiment, a high-capacity non-aqueous electrolyte having a structure in which the structure is sealed via the gasket 40 by the caulking portion even when affected by heat such as when mounting the reflow is highly durable and has improved liquid leakage resistance. There is an effect that the secondary battery 1 can be provided.

FIG. 4 shows a conventional example of a non-aqueous electrolyte secondary battery in which a positive electrode 100 is housed in a reverse hat type battery inner case 101, a collar 102 is provided at an opening of the battery inner case 101, and a gasket 103 is provided by the flange 102. Shows the structure supporting the bottom of the.
In the structure shown in FIG. 4, the outer peripheral portion 108 of the negative electrode can 107 is inserted inside the opening 106 of the positive electrode can 105, and the gasket 103 is provided so as to surround the tip end side of the outer peripheral portion 108.
In this structure, the opening peripheral edge portion of the positive electrode can 105 is crimped to form a caulked portion 110, and the positive electrode can 105 is sealed.

In the structure shown in FIG. 4, when the crimped portion 110 is formed by crimping the opening peripheral portion of the positive electrode can 105, the flange portion 102 may be deformed as shown by the chain line in FIG.
In contrast to this structure, in the structures shown in FIGS. 1 and 2, since the spacer 15 supports the gasket 40 from the bottom side, defects such as distortion and deformation do not occur in the structure of the sealing portion by the gasket 40.

[Second Embodiment of Non-Water Electrolyte Secondary Battery]
FIG. 3 shows the structure of the second embodiment of the non-aqueous electrolyte secondary battery. In the non-aqueous electrolyte secondary battery 60 of the second embodiment, the non-aqueous electrolyte secondary battery of the first embodiment is shown. What is different from the configuration of 1 is the structure of the spacer 65.
In this second embodiment, the spacer 65 is composed of a ring portion 65A which is a laminated body of a plurality of auxiliary rings 65a (7 in FIG. 3). The spacer 65 having the ring portion 65A made of the laminated body of the auxiliary ring 65a has the same outer diameter and inner diameter as the spacer 15 of the first embodiment, and is formed to have the same thickness.
Other structures are the same as those of the above-mentioned non-aqueous electrolyte secondary battery 1.
Since FIG. 3 shows the state before caulking, the non-aqueous electrolyte secondary battery of the second embodiment is completed by caulking the peripheral edge portion 12b of the positive electrode can 12.

The auxiliary ring 65a constituting the spacer 65 is made of the same material as the material constituting the spacer 15.
Since the structure of the other parts is the same as the structure of the first embodiment, the description of the structure of the other parts will be omitted.

Also in the structure of the second embodiment, since the spacer 65 supports the bottom portion of the gasket 40, even if the caulked portion is formed by caulking, the structure of the sealing portion maintains the desired structure. Therefore, even with the structure of the second embodiment, the same effect as that of the structure of the first embodiment can be obtained.
Since the spacer 65 is a laminated body of a plurality of auxiliary rings 65a, it has a feature that the height can be easily adjusted. Even when the non-aqueous electrolyte secondary battery 60 has a structure higher than that shown in FIG. 3, a required number of auxiliary rings 65a may be prepared according to the height and laminated. When the non-aqueous electrolyte secondary battery 60 has a structure lower than that shown in FIG. 3, it can be dealt with by reducing the number of laminated batteries.

Further, the auxiliary rings 65a constituting the spacer 65 do not all have to have the same thickness. For example, a part of the auxiliary ring 65a can be formed thinly, and the thin auxiliary ring 65a can be used for fine adjustment of the height.
By fine-tuning the overall thickness of the spacer 65 using the thin auxiliary ring 65a, even if the distance between the bottom surface 40a of the gasket 40 and the inner bottom surface of the positive electrode can 12 is not as designed, the gasket 40 can be used. The spacer 65 can be arranged without a gap between the bottom surface 40a and the inner bottom surface of the positive electrode can 12.
By arranging the spacer 65 on the inner bottom surface side of the positive electrode can 12 without a gap, when the opening of the positive electrode can is caulked, the desired shape is maintained without applying unnecessary distortion or load to the structure around the gasket 40. A sealing structure can be realized.

By the way, in the embodiments shown in FIGS. 1 to 3, the spacers 15 and 65 are drawn in a simple ring shape, but the spacers 15 and 65 are not limited to the simple ring shape and are reinforced on the outer peripheral portion and the inner peripheral portion thereof. The shape may be provided with ribs, protrusions, or the like.
For example, in the structure shown in FIG. 2, since there is a gap between the outer peripheral surface of the positive electrode 10 and the inner peripheral surface of the spacer 15, reinforcing ribs, protrusions, or the like may be formed on the inner peripheral surface of the spacer 15. Further, it is not necessary that all the outer peripheral surfaces 15b of the spacer 15 are in contact with the inner peripheral surface of the positive electrode can 12, and unevenness or reinforcing ribs may be provided along the outer peripheral surface of the spacer 15. In this case, the upper surface of the spacer 15 does not support the entire surface of the bottom surface 40a of the gasket 40, but the spacer 15 supports the bottom surface 40a of the gasket 40 to the extent that the gasket 40 does not undergo unnecessary deformation due to the pressure due to caulking. You just have to do it. Therefore, the ring portion 15A of the spacer 15 shown in FIG. 2 may have irregularities or reinforcing ribs as long as it has sufficient strength so as not to be deformed by the pressure of caulking, and the peripheral wall of the ring portion 15A itself may have. It may have a hollow structure.

1 ... Non-aqueous electrolyte secondary battery, 2 ... Storage container, 10 ... Positive electrode, 12 ... Positive electrode can, 12A ... Peripheral wall, 12a ... Opening, 12b ... Peripheral part, 15 ... Spacer, 15A ... Ring part, 15a ... Top surface, 15b ... outer peripheral surface, 15c ... bottom surface, 20 ... negative electrode, 22 ... negative electrode can, 22a ... outer peripheral end, 30 ... separator, 40 ... gasket, 40A ... outer edge, 40a ... bottom surface, 40B ... inner edge, 40C ... bottom wall Part, 41 ... annular groove, 50 ... electrolytic solution, 60 ... non-aqueous electrolyte secondary battery, 65 ... spacer, 65a ... auxiliary ring.

Claims (4)

A bottomed cylindrical positive electrode can and
A negative electrode can that is fixed with a gasket inside the opening of the positive electrode can and forms a storage space between the positive electrode can and the positive electrode can is provided.
A non-aqueous electrolyte secondary battery in which the accommodation space is sealed by crimping the opening of the positive electrode can to the negative electrode can side, and the positive electrode, the negative electrode, the electrolytic solution, and the separator are accommodated in the accommodation space. There,
A spacer having a ring portion located between the bottom surface of the gasket and the inner bottom surface of the positive electrode can is provided on the inner bottom side of the positive electrode can.
The ring portion has a thick wall in which the outer peripheral surface thereof is brought into contact with the inner peripheral surface on the bottom side of the positive electrode can, the bottom surface thereof is brought into contact with the inner bottom surface of the positive electrode can, and the upper surface thereof is brought into contact with almost the entire bottom surface of the gasket. A non-aqueous electrolyte secondary battery characterized by being formed in an annular shape . The gasket is in close contact with the outer peripheral surface of the side wall opening end of the negative electrode can, the inner edge portion of the negative electrode can in close contact with the inner peripheral surface of the side wall opening end, and the side wall opening end of the negative electrode can. The non-aqueous electrolyte secondary battery according to claim 1, further comprising a bottom wall portion connecting the outer edge portion and the inner edge portion, and the ring portion is in contact with the bottom wall portion . The non-aqueous electrolyte secondary battery according to claim 1 or 2 , wherein the ring portion is composed of a laminated body of a plurality of auxiliary rings. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3 , wherein the positive electrode is arranged inside the ring portion .

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