JP2001052674A - Cylindrical secondary battery - Google Patents

Abstract

(57) [Problem] To provide a cylindrical secondary battery in which the structure of a gas discharge valve is compact and easy to install, and can reduce the number of battery assembly steps. SOLUTION: In the cylindrical secondary battery according to the present invention,
A stepped hole 16 is formed in the lid constituting the battery can, and the gas discharge valve 5 is screwed and fixed to an inner screw 15 formed in the stepped hole 16. The gas discharge valve 5 includes a disc-shaped valve membrane 7 that opens when the internal pressure exceeds a predetermined value, a pair of clamping rings 6, 8 disposed on both sides of the valve membrane 7, and one clamping ring 8.
And an O-ring 58 interposed between the valve membrane 7 and an outer screw 83 screwed to the inner screw 15 of the lid is formed on the outer peripheral surface of the pressure ring 8 disposed outside the valve membrane 7. ing.
Cylindrical portions 62 and 82 are respectively provided on both the pressing rings 6 and 8 toward the outer peripheral portion of the valve membrane 7.
The thin portion 71 is formed by the pinching pressure between 2 and 82.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accommodating an electrode body serving as a secondary battery element in a battery can and extracting power generated by the secondary battery element from a pair of electrode terminals attached to the battery can. The present invention relates to a cylindrical secondary battery capable of performing the following.

[0002]

2. Description of the Related Art In recent years, lithium secondary batteries having a high energy density have attracted attention as power sources for portable electronic devices, electric vehicles and the like. For example, as shown in FIG. 7, a cylindrical lithium secondary battery having a relatively large capacity used in an electric vehicle has a cylindrical body (12) welded and fixed to each end of a cylindrical body (11). A battery can (1) is formed, and a wound electrode body (2) is housed inside the battery can (1). An electrode terminal mechanism (9) is attached to the lid (12),
(2) and the electrode terminal mechanism (9) are connected to each other by a plurality of current collecting tabs (3). A similar electrode terminal mechanism (not shown) is also attached to a lid (not shown) fixed to the other end of the cylindrical body (11), and power generated by the winding electrode body (2) is provided. Can be taken out from the pair of electrode terminal mechanisms. A spring return type gas discharge valve (13) is attached to each lid (12).

The wound electrode body (2) has a separator (22) impregnated with a non-aqueous electrolyte interposed between a positive electrode (21) containing a lithium composite oxide and a negative electrode (23) containing a carbon material. These are spirally wound. A plurality of current collecting tabs (3) are respectively drawn from the positive electrode (21) and the negative electrode (23) of the winding electrode body (2), and a plurality of current collecting tabs having the same polarity are provided.
The tip (31) of (3) is connected to one electrode terminal mechanism (9). In FIG. 7, for convenience, only a state in which the tip of a part of the current collecting tabs is connected to the electrode terminal mechanism (9) is shown, and the other current collecting tabs are connected to the electrode terminal mechanism (9). Illustration of the connected distal end portion is omitted.

The electrode terminal mechanism (9) is provided with a lid (1) of the battery can (1).
The screw member (91) has a flange (92) formed at the base end of the screw member (91). An insulating packing (93) is attached to the through-hole of the lid (12), so that electrical insulation and sealing between the lid (12) and the fastening member (91) are maintained. A washer (94) is fitted into the screw member (91) from the outside of the cylinder (11), and a nut (95) is screwed into the screw member (91). The nut (95) is tightened, and the insulating packing (93) is clamped between the flange (92) of the screw member (91) and the washer (94), thereby enhancing the sealing performance. The distal end portions (31) of the plurality of current collecting tabs (3) are provided with a flange portion of a screw member (91).
(92) is fixed by spot welding or ultrasonic welding.

[0005] As shown in FIG. 8, a pressure release type gas that is broken and opened when the internal pressure of the battery can (1) exceeds a predetermined value is inserted into a through hole (14) formed in the lid (12). A cylindrical secondary battery equipped with a discharge valve (4) is known (Japanese Patent Laid-Open No. 6-68861,
JP-A-9-139196). As shown in the figure, the pressure release type gas discharge valve (4) is formed by fixing a disc-shaped valve membrane (42) made of aluminum foil having a thickness of about 20 μm to the back surface of a ring body (41). The outer periphery of (41) is a through hole (14) of the lid (12).
Is laser-welded to the opening edge thereof and fixed to the lid (12).

[0006]

However, in the case of a cylindrical secondary battery having a spring return type gas discharge valve (13) shown in FIG. 7, when the pressure inside the battery can (1) rises,
The gas discharge valve (13) will be opened against the spring return force, but if a sudden pressure rise occurs, the gas discharge valve (13)
There is a problem that the pressure cannot be sufficiently released at the initial stage when the opening area is small. Further, since there are many components such as a spring and a valve mechanism, and the height exceeds the electrode terminal mechanism (9) as shown in FIG. 7, for example, when an assembled battery is configured by arranging a plurality of secondary batteries, There is a problem that the housing becomes large.

On the other hand, in a cylindrical secondary battery having a pressure release type gas discharge valve (4) shown in FIG. 8, when an abnormal pressure is generated inside the battery can (1), the valve membrane (42) Is instantaneously broken and the pressure is released, so that an increase in pressure is effectively suppressed. Also, the pressure release type gas discharge valve (4) has a smaller number of components and can be made smaller than the spring return type gas discharge valve (13), so that it can be made compact even when configuring an assembled battery. It is possible.

However, in a conventional cylindrical secondary battery provided with a pressure release type gas discharge valve (4), especially when the size of the battery is increased, the gas discharge valve is attached to the lid (12) of the battery can (1). There was a problem that it was difficult to weld (4). That is, as the size of the battery increases, the thickness of the lid (12) increases. For example, the ring (41) of the gas discharge valve (4) is attached to the lid (12) having a thickness of several mm or more by laser. When welding, the thickness of the lid (12) is very large compared to the thickness of the ring (41), so the heat dissipated during welding is remarkable, and the metal melted by laser irradiation cools rapidly As a result, defects such as pinholes and cracks may occur in the welded portion.

In a conventional cylindrical secondary battery provided with a pressure release type gas discharge valve (4), when an electrolyte is injected into a battery can (1) in an assembling process, a cover (12) is used. Since the gas discharge valve (4) is fixedly welded to (2), a screw hole for injecting the electrolyte must be separately provided, and after the electrolyte is injected, the screw hole must be closed. As a result, there is a problem that not only the configuration becomes complicated but also the number of assembling steps increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylindrical secondary battery in which the structure of the gas discharge valve is compact, which can be easily mounted, and which can reduce the number of battery assembly steps. It is.

[0011]

In the cylindrical secondary battery according to the present invention, a stepped hole (16) is formed in a lid (12) of a battery can (1), and the stepped hole (16) is formed. Is a large-diameter hole (17) which is opened to the outside of the lid (12) and has an internal thread formed on the inner peripheral surface, and a lid
It has a small-diameter hole (18) opening inside (12) and a step (19) interposed between the large-diameter hole (17) and the small-diameter hole (18). A gas discharge valve (5) is installed inside the large-diameter hole (17) of the stepped hole (16), and the gas discharge valve (5) is provided with a step (19) of the stepped hole (16).
A disc-shaped valve membrane (7) installed on the battery can (1) and opened when the internal pressure of the battery can (1) exceeds a predetermined value, and a stepped hole (16) formed by the outer periphery of the valve membrane (7). (19) a fixing device for fixing on the outer surface of the fixing device, the outer peripheral surface of the fixing device is formed with an external screw to be screwed with the internal screw of the large diameter hole (17) of the stepped hole (16). I have.

In the cylindrical secondary battery of the present invention, the valve membrane (7) is provided on the step (19) of the lid (12) of the battery can (1),
The valve membrane (7) can be fixed on the step (19) by screwing the external screw of the fixing device into the internal screw of the stepped hole (16). Therefore, it is not necessary to fix the gas discharge valve (5) to the lid (12) by welding. In addition, in the assembling process of the cylindrical battery of the present invention, after the electrolyte is injected from the stepped hole (16) of the lid (12) of the battery can (1), the pressure inside the battery can (1) is increased. When the electrolyte is impregnated into the separator by applying
A sealing plug is screwed into the inner screw of (16), and after the pressurizing step, the sealing plug is removed and the gas discharge valve (5) is screwed into the inner screw of the stepped hole (16) to be fixed. I can do it. Therefore, it is not necessary to separately provide an electrolyte injection hole in the lid (12) of the battery can (1).

Further, the pressure release type gas discharge valve (5)
Since the number of parts is smaller than that of the reset type gas discharge valve and it can be configured compactly, it can be housed and deployed entirely in the thickness area sandwiched between the inner surface and the outer surface of the lid (12). . Therefore, when an assembled battery is configured using the cylindrical secondary battery according to the present invention, the entire device can be downsized.

[0014] In a specific configuration, the fixing device is a valve membrane.
(7) A pair of squeezing rings (6) arranged on both sides of the squeezing ring
(8), at least one of the pressure ring (8) and the valve membrane
(7) and an O-ring (58) interposed between the
The outer thread (83) is formed on the outer peripheral surface of a pressure ring (8) disposed outside of (7), and the outer peripheral portions of the valve membrane (7) are respectively formed on both pressure rings (6) and (8). The cylindrical portions (62) and (82) are protruded toward the outer circumferential surface of the cylindrical portion (62) of the other pressing ring (8). It is formed smaller than the inner diameter by a predetermined dimension, and a thin portion (71) is formed on the valve membrane (7) by the pressing force of the cylindrical portions (62) and (82) of the two pressing rings (6) and (8). Have been.

In the specific configuration, the outer pressing ring is provided.
By screwing the outer screw (83) of (8) into the inner screw (15) of the lid (12), a clamping force is generated in both clamping rings (6) and (8),
The outer periphery of the valve membrane (7) is sandwiched by the two clamping rings (6) and (8), and the O-ring (58) is sandwiched by the front surface of the valve membrane (7) and the back surface of the outer clamping ring (8). You. Here, in the cylindrical portions (62) and (82) protruding from both the pressing rings (6) and (8), the outer diameter of one cylindrical portion (62) is larger than the inner diameter of the other cylindrical portion (82). Are also made smaller by the specified size,
(62) and (82) can be fitted to each other, and by this fitting, a ring-shaped member having a predetermined dimension is provided between the outer peripheral surface of one cylindrical portion (62) and the inner peripheral surface of the other cylindrical portion (82). A space will be formed. Therefore, the outer peripheral portion of the valve membrane (7) is pressed by the two cylindrical portions (62) and (82) to press the ring-shaped space into a mold space. A thin portion (71) having a predetermined thickness defined by the dimensions of (1) is formed.

As described above, a thin portion (71) having a predetermined thickness is formed on the valve membrane (7).
In the pressure release type gas discharge valve (5) in which
When a pressure exceeding a predetermined value is generated inside the battery can (1), first, the thin portion (71) is broken, and the valve membrane (7) is instantaneously broken.
Will be open. Therefore, the operating pressure of the gas discharge valve (5) depends on the thickness of the thin portion (71) of the valve membrane (7), that is, the dimensions of the cylindrical portions (62) and (82) of both the clamping rings (6) and (8). It can be defined with high accuracy.

[0017] In another specific configuration, the fixing device includes a valve membrane provided on the step (19) of the stepped hole (16) of the lid (12).
Lower pressure ring to lower pressure with the outer periphery of (7) directed toward step (19)
(50), and an outer screw (52) screwed to the inner screw (15) of the lid (12) is formed on the outer peripheral surface of the ring-shaped main body overlapping the lower pressure ring (50), and the ring-shaped main body is formed. An outer peripheral tightening ring (51) having an inner screw (53) formed on the inner peripheral surface thereof and an outer screw (56) formed to be screwed into the inner screw (53) of the outer peripheral tightening ring (51). Circumferential tightening ring (54) and inner circumferential tightening ring (54)
And an O-ring (59) interposed between the valve membrane (7).

In this specific construction, the outer peripheral side tightening ring (51) is screwed into the inner screw (15) of the lid (12) so that the lower pressure ring (50) lowers the outer peripheral portion of the valve membrane (7). The valve membrane (7) is thereby clamped between the step (19) of the stepped hole (16) and the lower pressure ring (50). Also, the inner circumference side tightening ring (54)
The O-ring (59) is screwed into the inner screw (53) of the outer-side tightening ring (51) so that the O-ring (59) and the lower pressure ring
It is pinched by the back surface of (50). According to the configuration in which the clamping of the valve membrane (7) is performed by tightening the outer circumferential side tightening ring (51) while the clamping pressure of the O-ring (59) is performed by tightening the inner circumferential side tightening ring (54), Can be individually adjusted, and an optimum clamping force can be given. Further, since the outer peripheral side tightening ring (51) and the inner peripheral side tightening ring (54) are arranged on the same plane, the thickness of the gas discharge valve (5) can be reduced.

[0019]

According to the cylindrical secondary battery of the present invention, the gas exhaust valve can be made compact by employing a pressure release type gas exhaust valve, and the gas exhaust valve is connected to the stepped hole of the lid. By adopting a structure in which the gas discharge valve is screwed and fixed, the gas exhaust valve can be easily mounted, and the stepped hole can be used for injecting the electrolyte, thereby reducing the number of steps for assembling the battery.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIG. 1, a cylindrical secondary battery according to the present invention includes a cylindrical battery can (1) formed by welding and fixing a lid (12) to each end of a cylindrical body (11). It is configured to house the winding electrode body (2). An electrode terminal mechanism (9) is attached to the lid (12),
The winding electrode body (2) and the two-electrode terminal mechanism (9) are connected to each other by a plurality of current collecting tabs (3). In addition, cylindrical body
A similar electrode terminal mechanism (not shown) is also attached to a lid (not shown) welded and fixed to the other end of (11), and the power generated by the winding electrode body (2) is supplied to a pair of electrodes. It can be taken out from the terminal mechanism. Also, each lid
A pressure release type gas discharge valve (5) is screwed into and fixed to the stepped hole (16) opened in (12).

The wound electrode body (2) has a separator (22) impregnated with a non-aqueous electrolyte interposed between a positive electrode (21) containing a lithium composite oxide and a negative electrode (23) containing a carbon material. These are spirally wound. A plurality of current collecting tabs (3) are respectively drawn from the positive electrode (21) and the negative electrode (23) of the winding electrode body (2), and a plurality of current collecting tabs having the same polarity are provided.
The tip (31) of (3) is connected to one electrode terminal mechanism (9). In FIG. 1, for convenience, only a state in which the tip of a part of the current collecting tabs is connected to the electrode terminal mechanism (9) is shown, and the other current collecting tabs are connected to the electrode terminal mechanism (9). Illustration of the connected distal end portion is omitted.

The electrode terminal mechanism (9) is a cover (1) for the battery can (1).
The screw member (91) has a flange (92) formed at the base end of the screw member (91). An insulating packing (93) is attached to the through-hole of the lid (12), so that electrical insulation and sealing between the lid (12) and the fastening member (91) are maintained. A washer (94) is fitted into the screw member (91) from the outside of the lid (12), and a nut (95) is screwed into the screw member (91). The nut (95) is tightened, and the insulating packing (93) is clamped between the flange (92) of the screw member (91) and the washer (94), thereby enhancing the sealing performance. The distal end portions (31) of the plurality of current collecting tabs (3) are provided with a flange portion of a screw member (91).
(92) is fixed by spot welding or ultrasonic welding.

As shown in FIG. 3, a stepped hole (16) formed in the lid (12) of the battery can (1) opens outside the lid (12) and has an internal thread ( A large-diameter hole (17) in which 15) is formed,
It comprises a small-diameter hole (18) opening inside the lid (12), and a step (19) interposed between the large-diameter hole (17) and the small-diameter hole (18).

The gas discharge valve (5) is, as shown in FIGS.
A disk-shaped valve membrane (7) made of aluminum foil having a predetermined thickness (for example, 20 μm), and a pair of brass pressure rings (6) and (8) for pressing the outer peripheral portion of the valve film (7) from above and below, An O-ring (58) made of silicone resin is interposed between the valve membrane (7) and the outer clamping ring (8). Gas exhaust valve
The valve membrane (7) of (5) can be formed of not only aluminum but also nickel or stainless steel.

The inner clamping ring (6) is formed by projecting a cylindrical portion (62) upward on the surface of a disk portion (61) having a central hole (63). Also, the outer pressing ring (8) has a central hole (80).
The disk portion (81) has a cylindrical portion (82) projecting downward from the rear surface thereof, and an outer thread (83) is formed on the outer peripheral surface of the disk portion (81). Here, the cylindrical portion (6
2) and the cylindrical portion (82) of the outer pressing ring (8) are located coaxially. The outer diameter of the cylindrical portion (62) of the inner pressing ring (6) is smaller than the inner diameter of the cylindrical portion (82) of the outer pressing ring (8) by a predetermined dimension (for example, 36 μm). The cylindrical portion (62) of the inner pressing ring (6) and the cylindrical portion (82) of the outer pressing ring (8) can be fitted to each other.

In assembling the gas discharge valve (5), as shown in FIG. 3, the step (19) of the stepped hole (16) of the lid (12) is
After the inner pressing ring (6), the valve membrane (7) and the O-ring (58) are installed in this order, the outer pressing ring (15) is screwed into the inner screw (15) of the stepped hole (16) of the lid (12). 8) Screw in the outer screw (83). Thereby, as shown in FIG. 4, the outer peripheral portion of the valve membrane (7) is pressed by the inner pressing ring (6) and the outer pressing ring (8),
The cylindrical part (62) of the inner pressing ring (6) and the outer pressing ring (8)
The cylindrical portion (82) becomes a mold, and the outer peripheral portion of the valve membrane (7) is formed into a cylindrical portion (62) and a disk portion (61) of an inner pressing ring (6) as shown in the figure.
Plastic deformation along the surface of. This allows the valve membrane
(7) includes a thin portion (71 μm) having a predetermined thickness (for example, 18 μm) defined by a gap S between the two cylindrical portions (62) and (82) in a region sandwiched between the two cylindrical portions (62) and (82). ) Is formed in a ring shape.

The O-ring (58) is pressed between the outer pressing ring (8) and the surface of the valve membrane (7) by screwing in the outer pressing ring (8). 8) and leaflet (7)
A seal will be applied between the two.

In assembling the cylindrical secondary battery having the gas discharge valve (5), a stepped hole in the lid (12) of the battery can (1) is used.
After injecting the electrolyte from (16) into the inside of the battery can (1), a sealing stopper (not shown) is screwed into the stepped hole (16) and sealed, and in this state, the inside of the battery can (1) is inserted. The electrolyte is taken up by applying a predetermined pressure to impregnate the separator (22) of the electrode body (2).
Thereafter, the sealing plug is removed, and the gas discharge valve (5) is screwed into the stepped hole (16) and fixed.

In the cylindrical secondary battery assembled as described above, when the pressure inside the battery can (1) increases, first, the thin portion (71) of the valve membrane (7) is broken, and the valve membrane (7) is broken.
(7) is released instantaneously and the internal pressure is released to the outside at a stretch. Here, the opening pressure of the valve membrane (7) depends on the thickness of the thin portion (71) of the valve membrane (7), that is, the outer diameter of the cylindrical portion (62) of the inner pressing ring (6) and the outer pressing ring (8). ) Can be accurately defined by the inner diameter of the cylindrical portion (82).

FIGS. 5 and 6 show another example of the structure of the gas discharge valve (5). The gas discharge valve (5) is provided on the step (19) of the stepped hole (16) of the lid (12), as in the valve valve described above.
(7), a lower pressure ring (50) for lowering the outer peripheral portion of the valve membrane (7) toward the step (19), and an outer screw on an outer peripheral portion of the ring-shaped main body overlapping the lower pressure ring (50). (52) and an outer tightening ring (51) having an inner screw (53) in the inner circumferential portion, and an outer screw (56) screwed into the inner screw (53) of the outer tightening ring (51). Inner ring (54) and inner ring (5
4) and an O-ring (59) interposed between the valve membrane (7), and a cylindrical portion (5
5) is projected downward, and a central hole (57) coaxial with the stepped hole (16) is formed in the center of the inner peripheral side tightening ring (54).

In assembling the gas discharge valve (5), the valve membrane (7) and the lower pressure ring (50) are sequentially installed on the step (19) of the stepped hole (16) of the lid (12). After that, the stepped hole (1
The outer screw (52) of the outer peripheral side tightening ring (51) is screwed into the inner screw (15) of 6). After the O-ring (59) is installed on the valve membrane (7), the outer screw (56) of the inner-side tightening ring (54) is screwed into the inner screw (53) of the outer-side tightening ring (51). . As a result, as shown in FIG. 5, the outer periphery of the valve membrane (7) is pressed between the step (19) of the stepped hole (16) and the lower pressure ring (50), and the valve membrane (7) is closed. Fixed to (12). Further, an O-ring (58) is pressed between the inner peripheral side tightening ring (54) and the surface of the valve membrane (7), and a seal is formed between the inner peripheral side tightening ring (54) and the valve membrane (7). Will be applied.

In the cylindrical secondary battery provided with the above-mentioned gas discharge valve (5), an outer peripheral side fastening ring (51) is used to make a valve membrane.
A sufficient tightening force can be applied to (7), and an appropriate tightening force can be applied to the O-ring (59) by using the inner circumferential side tightening ring (54). Further, since the outer peripheral side tightening ring (51) and the inner peripheral side tightening ring (54) are arranged on the same plane, the thickness can be further reduced than the gas discharge valve (5) shown in FIGS. It is.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cylindrical secondary battery according to the present invention (Examples 1 to 4) shown in FIGS. 1 to 4 and a conventional cylindrical secondary battery shown in FIG.
(Comparative Example) was prepared, and the effect of the present invention was confirmed. First,
After describing the steps common to each battery, the structure of the gas discharge valve that differs for each battery and its attachment will be described.

[0034]Preparation of positive electrode  LiCoO as positive electrode active material₂(Lithium composite oxide)
And carbon as a conductive agent in a weight ratio of 90: 5,
A mixture was prepared. Next, polyvinylidene fluoride as a binder
Den was dissolved in N-methyl-2-pyrrolidone (NMP)
Thus, an NMP solution was prepared. Then, the positive electrode mixture and polyf
Positive electrode mixture so that the weight ratio of vinylidene fluoride is 95: 5
And NMP solution to prepare a slurry.
Lead on both sides of the aluminum foil as the positive electrode current collector.
Coating by tar blade method, vacuum at 150 ° C for 2 hours
Drying was performed to produce a positive electrode.

[0035]Fabrication of negative electrode  Dissolve polyvinylidene fluoride as a binder in NMP
To prepare an NMP solution, graphite powder having a particle diameter of 10 μm and
Mix so that the weight ratio of vinylidene fluoride is 85:15.
A slurry was prepared by kneading. This slurry is used as a negative electrode current collector.
By doctor blade method on both sides of copper foil as
And vacuum dried at 150 ° C. for 2 hours to produce a negative electrode.
Was.

[0036]Preparation of electrolyte  Volume ratio of ethylene carbonate and diethyl carbonate
LiPF was added to the solvent mixed at 1: 1.₆At a rate of 1 mol / l
And dissolved to prepare an electrolytic solution.

[0037]Battery assembly  Multiple electrodes are placed on the surface of the aluminum foil that constitutes the positive electrode.
Welding the Luminum current collector tabs at regular intervals
In addition, the surface of the copper foil that constitutes the negative electrode
The current collector tabs were welded at regular intervals. And the positive electrode
Spirally with a separator between the
A scraping electrode body was configured. As a separator,
An on-permeable polyethylene microporous membrane was used. This
The winding electrode body of the above is loaded into the inside of a cylindrical body that becomes a battery can,
The positive and negative current collecting tabs extending from the winding electrode body
Each was connected to the electrode terminal mechanism attached to the lid
Thereafter, the lid is welded and fixed to the cylinder to assemble the cylindrical secondary battery.
I stood up. The battery can has an outer diameter of 45 mm and a length of 20 mm.
0mm, the thickness of the cylinder is 1.25mm,
The diameter is 45 mm and the thickness is 5 mm. or,
The total length of the battery including the pair of positive and negative electrode terminals is 220 mm
It is.

[0038]Example 1  A stepped hole with an inner diameter of 5 mm is opened in the lid,
Made of aluminum foil with a thickness of 30 μm for the hole
Attach the gas exhaust valve (5) of FIGS. 1-3 with a valve membrane
Thus, a cylindrical secondary battery of Example 1 was produced.

[0039]Example 2  The use of a valve membrane made of nickel foil with a thickness of 20 μm
Other than the above, the cylindrical secondary battery of the second embodiment is the same as that of the first embodiment.
It was created.

[0040]Example 3  Use a valve membrane made of stainless steel foil with a thickness of 10 μm.
In the same manner as in Example 1 except that
Battery was created.

[0041]Comparative Example 1  Connect the pressure release type gas discharge valve (4) shown in FIG. 8 to the lid (12).
By performing laser welding, a cylindrical secondary battery of Comparative Example 1 was produced.

[0042]Comparative Example 2  As shown in FIG. 7, the spring return type gas discharge valve (13) is connected to the lid (12).
Into the cylindrical secondary battery of Comparative Example 2
did. The total length of the battery including the pair of gas discharge valves (13) (13)
Is 225 mm.

[0043]Calculation of volume energy density  The capacity of each battery of Examples 1 to 3 and Comparative Examples 1 and 2 was
It measured and calculated volume energy density. The results are displayed
It is shown in FIG. The volume of the battery depends on the electrode terminal mechanism and gas exhaust.
The volume was defined as the volume of a cylindrical body containing the entire battery including the outlet valve.

[0044]

[Table 1]

As is clear from Table 1, the same battery energy was obtained in all the batteries, but the batteries of Examples 1 to 3 and Comparative Example 1 were different from those of Comparative Example 2 due to the difference in battery volume.
Has a larger volume energy density than that of the battery.

Further, when a leak check test using a soap solution was performed, Examples 1 to 3 in which the gas discharge valve was screwed in and no welding was performed were the same as Comparative Example 1 in which the gas discharge valve was welded and fixed. No gas leak was found.

According to the cylindrical secondary battery of the present invention, when the electrolyte is injected into the inside of the battery can in the battery assembling process, the conventional battery (Comparative Example 1) shown in FIG. Although it is necessary to open a hole for injecting the electrolyte, the battery of the present invention can utilize a stepped hole formed in the cylindrical body, so that the configuration is simplified. The gas discharge valve (5) is a lid
Since it is embedded and fixed in (12), the electrode terminal mechanism
There is no problem of interfering with (9), and the opening area of the valve can be increased as compared with the configuration in which the gas discharge valve is protruded from the lid (12).

Further, when assembling an assembled battery using a plurality of secondary batteries, according to the battery of the present invention, the pressure release type gas discharge valve (5) is set within the thickness range of the lid (12). Since the batteries can be accommodated and arranged, the operation of connecting the batteries to each other with the conducting wires is not hindered by the gas discharge valve, and the assembling work is facilitated. Furthermore, when a plurality of secondary batteries are connected in series to form an assembled battery, according to the battery of the present invention, compared to a case where a similar assembled battery is formed using a conventional secondary battery, The housing can be downsized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cylindrical secondary battery according to the present invention.

FIG. 2 is an exploded perspective view of a gas discharge valve provided in the cylindrical secondary battery.

FIG. 3 is an enlarged sectional view showing a state before the gas discharge valve is tightened.

FIG. 4 is an enlarged sectional view showing a state after the gas discharge valve is tightened.

FIG. 5 is a cross-sectional view illustrating another configuration of the gas discharge valve.

FIG. 6 is an exploded perspective view of the gas discharge valve.

FIG. 7 is a cross-sectional view of a conventional cylindrical secondary battery provided with a spring return type gas discharge valve.

FIG. 8 is a sectional view of a conventional cylindrical secondary battery provided with a pressure release type gas discharge valve.

[Explanation of symbols]

 (1) Battery can (11) Cylindrical body (12) Lid (2) Winding electrode body (3) Current collecting tab (5) Gas exhaust valve (58) O-ring (6) Inner clamping ring (62) Cylinder Part (7) Valve membrane (8) Outer clamping ring (82) Cylindrical part (9) Electrode terminal mechanism

Continued on the front page (72) Inventor Toshiyuki Noma 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Ikuro Yonezu 2-5-25 Keihanhondori, Moriguchi-shi, Osaka No. SANYO Electric Co., Ltd. F term (reference) 5H012 AA01 BB02 CC00 DD01 DD05 EE04 FF01 GG00 JJ03 JJ10 5H029 AJ14 AK03 AL07 AM03 AM05 AM07 BJ02 BJ14 CJ07 DJ02 HJ04 HJ15

Claims (5)

[Claims] An electrode body (2) serving as a secondary battery element is housed inside a battery can (1) having a lid (12) fixed to an opening of a cylindrical body (11) and airtight. In the cylindrical secondary battery, the lid (12) of the battery can (1) is provided with a stepped hole (16), and the stepped hole (16) is provided outside the lid (12). A large-diameter hole (17) with an internal thread formed on the inner peripheral surface
Small hole (18), large hole (17) and small hole (1
8), a gas exhaust valve (5) is installed inside the large-diameter hole (17) of the stepped hole (16), and the gas exhaust valve (19) is provided. 5) a disc-shaped valve membrane (7) installed on the step (19) of the stepped hole (16) and opened when the internal pressure of the battery can (1) exceeds a predetermined value; Insert the stepped hole (1)
And a fixing device for fixing on the step portion (19) of (6), and the outer peripheral surface of the fixing device has an external screw which is screwed into the inner screw of the large diameter hole (17) of the stepped hole (16). A cylindrical secondary battery, wherein a screw is formed. 2. A fixing device comprising: a pair of squeezing rings (6) and (8) arranged on both sides of a valve membrane (7); at least one of the squeezing rings (8) and the valve membrane (7). An outer ring (83) is formed on the outer peripheral surface of a pressure ring (8) disposed outside the valve membrane (7),
Cylindrical portions (62) and (82) are provided on both the pressing rings (6) and (8) toward the outer peripheral portion of the valve membrane (7), respectively.
The outer diameter of the cylindrical portion (62) of (6) is smaller than the inner diameter of the cylindrical portion (82) of the other pressure ring (8) by a predetermined dimension. The cylindrical part (6
2) The cylindrical secondary battery according to claim 1, wherein the thin portion (71) is formed by the pressure applied by (82). 3. An outer peripheral portion of the valve membrane (7) is subjected to a downward pressure by a cylindrical portion (82) of the other pressing ring (8), and a cylindrical portion (62) of the one pressing ring (6). 3. The cylindrical secondary battery according to claim 2, wherein the thin-walled portion (71) is plastically deformed along the outer peripheral surface of the battery, and the thin wall portion (71) is formed by the plastic deformation. 4. The fixing device lowers the outer peripheral portion of the valve membrane (7) installed on the step (19) of the stepped hole (16) of the lid (12) toward the step (19). The lower pressure ring (50) to be mounted and the inner screw (1) of the lid (12) are provided on the outer peripheral surface of the ring-shaped body overlapping the lower pressure ring (50).
An outer-side tightening ring (51) in which an outer screw (52) screwed to 5) is formed and an inner screw (53) is formed on the inner circumferential surface of the ring-shaped body, and an outer-side tightening ring (51) Inner peripheral side tightening ring (54) formed with an external screw (56) to be screwed into the internal screw (53)
The cylindrical secondary battery according to claim 1, further comprising an O-ring (59) interposed between the inner peripheral side fastening ring (54) and the valve membrane (7). 5. The gas discharge valve according to claim 1, wherein the gas discharge valve is entirely contained in a thickness region sandwiched between an inner surface and an outer surface of the lid body. Cylindrical secondary battery.