JP2000138047A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical secondary battery having compact and simple constitution free from an increase in assembling manhour, in a cylindrical secondary battery having a take-up electrode body housed in a battery can. SOLUTION: This cylindrical secondary battery is provided with a safety valve 5 having a pressure releasing plate 7, screwed and fixed to the cover 12 of a battery can 1. The safety valve 5 houses a pair of clamping rings in a cylindrical member 51 screwed to the tapped hole 15 of the cover 12 for clamping the pressure releasing plate 7 and the external surface thereof from upper and lower sides, and has fixing rings screwed for applying a clamping force to both clamping rings. In addition, cylindrical parts are respectively projected from both clamping rings toward the pressure releasing plate 7, and a thin part is formed on the pressure releasing plate 7 with the clamping force of both cylindrical parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery can, in which a wound electrode body serving as a secondary battery element is housed, and power generated by the secondary battery element is supplied from a pair of electrode terminals attached to the battery can. The present invention relates to a secondary battery that can be taken out.

[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. 4, a cylindrical lithium secondary battery having a relatively large capacity used in electric vehicles has a cylindrical shape in which lids (12) and (12) are fixed to both ends of a cylindrical body (11) by welding. A wound electrode body (2) is housed inside a battery can (1) in the shape of a circle. A pair of positive and negative electrode terminal mechanisms (9) and (9) are attached to the lids (12) and (12), and the take-up electrode body (2) and the two electrode terminal mechanisms (9) and (9) are attached. Are connected to each other by a plurality of current collecting tabs (3), so that electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (9) (9). . Also, the lid (1
2) is equipped with a return type safety valve (13).

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. 4, 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.

As shown in FIG. 5, a pressure relief type safety valve (4) which operates when the internal pressure of the battery can (1) exceeds a predetermined value is provided in a through hole (14) formed in the lid (12). ) Is known cylindrical type secondary battery (JP-A-6-68861, JP-A-9-13)
No. 9196). The safety valve (4) shown in FIG. 5 has a disc-shaped pressure release plate (42) made of aluminum foil having a thickness of about 20 μm fixed to the back surface of the ring body (41). The outer peripheral portion is fixed to the lid (12) by laser welding to the opening edge of the through hole (14) of the lid (12).

[0006]

However, in the case of a cylindrical secondary battery provided with a return-type safety valve (13) shown in FIG. 4, when the pressure inside the battery can (1) rises, the safety valve (13) returns. Although it is opened against the force, when the pressure rises sharply, there is a problem that the pressure cannot be sufficiently released at the initial stage when the opening area of the return type safety valve (13) is small. In addition, since there are many components such as springs and valve mechanisms, and the height exceeds the electrode terminal mechanism (9) as shown in FIG. 4, 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, a pressure relief type safety valve shown in FIG.
In the case of the cylindrical secondary battery provided with (4), when an abnormal pressure is generated inside the battery can (1), the pressure release plate (42) operates,
Since the pressure is released instantaneously, the rise in pressure is sufficiently suppressed. The pressure relief type safety valve (4) is a reset type safety valve (13).
Since the number of components is smaller and the size can be reduced, the size can be reduced even when a battery pack is configured. However, in a conventional cylindrical secondary battery having a pressure relief type safety valve (4), the battery can (1)
When the electrolyte is injected into the inside of the container, a safety valve (4) is placed on the lid (12).
Is fixed by welding, it is necessary to separately provide a screw hole for injecting the electrolytic solution, and to close the screw hole after injecting the electrolytic solution. This not only complicates the configuration, but also
There is a problem that the number of assembly steps increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylindrical secondary battery which is compact and has a simple structure without increasing the number of assembling steps.

[0009]

In the cylindrical secondary battery according to the present invention, when the internal pressure of the battery can (1) exceeds a predetermined value, the lid (12) constituting the battery can (1) is placed on the cover (12). A safety valve (5) provided with a disk-shaped pressure release plate (7) that operates in a fixed manner is screwed into a screw hole (15) formed in the lid (12).

In the cylindrical secondary battery according to the present invention, since the safety valve (5) of the pressure release type is screwed and fixed to the lid (12), the safety valve (5) is inserted into the battery can (1) during the assembly process. When the electrolyte is impregnated into the separator by applying pressure, the lid (1
A sealing plug is screwed into the screw hole (15) of the battery can (1) of 2). After the pressurizing step, the sealing plug is removed, and a safety valve (5) is inserted into the screw hole (15) of the battery can (1). Can be screwed in and fixed.

Further, the pressure relief type safety valve (5) has a smaller number of parts and can be constructed compactly as compared with a return type safety valve. It can be formed lower than the height of the electrode terminal mechanism (9). Therefore, when an assembled battery is configured using the cylindrical secondary battery according to the present invention, the entire device can be downsized.

In a specific configuration, the safety valve (5) is provided with a lid
A pressure release plate (7) and an outer peripheral portion of the pressure release plate (7) are clamped inside a cylindrical member (51) having an external thread (52) screwed into the screw hole (15) of (12). An inner screw (53) formed on the inner peripheral surface of the cylindrical member (51) is provided outside the two pressing rings (6) and (8) while accommodating a pair of pressing rings (6) and (8). A fixing ring (55) screwed to the cylinder is arranged, and cylindrical portions (63) and (82) protrude from both clamping rings (6) and (8) toward the pressure release plate (7). The outer diameter of the cylindrical portion (63) of one pressing ring (6) is larger than the inner diameter of the cylindrical portion (82) of the other pressing ring (8).
The pressure release plate (7) is formed to be small by a predetermined size, and a thin portion (71) is formed on the pressure release plate (7) by the pressing force of the cylindrical portions (63) and (82) of the two pressing rings (6) and (8). I have.

In the above specific configuration, the fixing ring (5
By screwing 5) into the inside of the cylindrical member (51), a clamping force is generated in both clamping rings (6) and (8), and the outer peripheral portion of the pressure release plate (7) is ) (8). Here, in the cylindrical portions (63) and (82) protruding from the two pressure rings (6) and (8), the outer diameter of one cylindrical portion (63) is larger than the inner diameter of the other cylindrical portion (82). Are also formed smaller by a predetermined dimension, the two cylindrical portions (63) and (82) can be fitted to each other, and by the fitting, the outer peripheral surface of one cylindrical portion (63) and the other cylindrical portion ( A ring-shaped space of a predetermined size is formed between the inner peripheral surfaces of the above (82). Therefore, the outer peripheral portion of the pressure release plate (7) is pinched by the two cylindrical portions (63) and (82),
Press processing is performed using the ring-shaped space as a mold space, and as a result, a thin portion (71) having a predetermined thickness defined by the dimensions of the ring-shaped space is formed. As described above, in the pressure relief valve (5) in which the thin portion (71) having a predetermined thickness is formed on the pressure release plate (7), when a pressure exceeding a predetermined value is generated inside the battery can (1). First, a break occurs in the thin portion (71), and the pressure release plate (7) operates instantaneously. Therefore, the operating pressure of the safety valve (5) depends on the thickness of the thin portion (71) of the pressure release plate (7), that is, the cylindrical portions (63) of the two clamping rings (6) and (8).
The dimension (82) can be precisely defined.

More specifically, between the opposing surfaces of the inner pressing ring (6) installed on the inner side of the battery can (1) and the cylindrical member (51), and on the outer side of the battery can (1). O-rings (57) and (58) are interposed between the opposing surfaces of the arranged outer pressing ring (8) and the pressure release plate (7). Thereby, the inside of the battery can (1) can be sealed with high airtightness.

[0015]

In the cylindrical secondary battery according to the present invention, the compactness is realized by the provision of the screw-in type pressure relief type safety valve, and the hole for screwing in the safety valve is used for injecting the electrolyte. Since it is possible, the configuration is simplified, and the number of assembly steps is reduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIGS. 1 and 2, a cylindrical secondary battery according to the present invention has a cylindrical battery can formed by welding and fixing lids (12) and (12) to both ends of a cylindrical body (11).
A winding electrode body (2) is housed inside (1). Both lids (12) and (12) have a pair of positive and negative electrode terminal mechanisms.
(9) (9) is attached, and the winding electrode body (2) and the two electrode terminal mechanisms (9) (9) are connected to each other by a plurality of current collecting tabs (3), and are wound. The power generated by the electrode body (2) can be taken out from the pair of electrode terminal mechanisms (9) (9). A pressure release type safety valve (5) is screwed and fixed in a screw hole (15) opened in 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. 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) 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 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.

The safety valve (5) comprises a cylindrical member (51) having a step (54) as shown in FIGS. 3 (a) and (b). The cylindrical member (51) has an external thread ( 52), an inner screw (53) is formed at the upper end, the outer screw (52) is screwed into the screw hole (15) of the lid (12), and the inner screw (53) has a fixing ring (55). Is fixed by screwing an external screw (56). A predetermined thickness is set inside the cylindrical member (51).
(For example, 20 μm), a disc-shaped pressure release plate (7) made of aluminum, and a pair of brass pressure rings (6) and (8) for pressing the outer periphery of the pressure release plate (7) from above and below. Are disposed coaxially with the cylindrical member (51), between the inner pressing ring (6) near the inner side of the battery can (1) and the step (54) of the cylindrical member (51), and the battery can ( O-rings (57) and (58) made of silicone are interposed between the outer pressing ring (8) closer to the outer side of (1) and the pressure release plate (7).

The inner pressing ring (6) has a sleeve (62) projecting downward from the back surface of the disk portion (61) and a disk portion (61).
A cylindrical portion (63) is provided so as to protrude upward from the surface thereof. The outer clamping ring (8) is configured by projecting a cylindrical portion (82) downward on the back surface of the disk portion (81). here,
The cylindrical part (63) of the inner pressing ring (6) and the outer pressing ring (8)
Is located coaxially with the cylindrical portion (82). Inner clamping ring
The outer diameter of the cylindrical portion (63) of (6) is formed smaller than the inner diameter of the cylindrical portion (82) of the outer pressing ring (8) by a predetermined dimension (for example, 36 μm). 6) cylindrical part (63)
The cylindrical portion (82) of the outer pressing ring (8) can be fitted to each other.

In assembling the safety valve (5), as shown in FIG. 3 (a), an O-ring (57), an inner clamping ring (6), a pressure release plate (7), After the outer clamping ring (8) and the fixing ring (55) are sequentially attached, the fixing ring (55) is screwed into the cylindrical member (51) as shown in FIG. As a result, the outer peripheral portion of the pressure release plate (7) is clamped between the inner pressing ring (6) and the outer pressing ring (8), and the cylindrical portion (63) of the inner pressing ring (6) and the outer portion are pressed. The cylindrical portion (82) of the pressure ring (8) is a mold, and the outer peripheral portion of the pressure release plate (7) is connected to the cylindrical portion (63) of the inner pressure ring (6) and the disk portion ( 6
Plastic deformation along the surface of 1). Thereby, the pressure release plate (7) has a region between the cylindrical portions (63) and (82),
A predetermined thickness defined by the gap S between the two cylindrical portions (63) and (82)
A thin portion (71) of (for example, 18 μm) is formed in a ring shape.

Also, by screwing the fixing ring (55),
An O-ring (57) is sandwiched between the inner pressing ring (6) and the step (54) of the cylindrical member (51), and an outer pressing ring (8).
An O-ring (58) is sandwiched between the pressure release plate (7) and the pressure release plate (7), thereby sealing between the inside and outside of the cylindrical member (51).

In assembling the cylindrical secondary battery provided with the safety valve (5), the electrolyte is introduced into the battery can (1) from the screw hole (15) of the lid (12) of the battery can (1). After injection, screw holes (15)
A sealing plug (not shown) is screwed into the container to seal it, and in this state, a predetermined pressure is applied to the inside of the battery can (1) to wind up the electrolyte and impregnate the separator (22) of the electrode body (2). . afterwards,
Remove the sealing plug and screw the safety valve (5) into the screw hole (15) to fix it.

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 pressure release plate (7) is broken. ,
The pressure release plate (7) operates instantaneously, and the internal pressure can be released to the outside at a stretch. Here, the operating pressure of the pressure release plate (7) is determined by the thickness of the thin portion (71) of the pressure release plate (7), that is, the outer diameter of the cylindrical portion (63) of the inner pressure ring (6) and the outer pressure. Accuracy can be defined by the inner diameter of the cylindrical portion (82) of the pressure ring (8).

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cylindrical secondary battery according to the present invention (Examples 1 to 4) shown in FIGS. 1 to 3 and a conventional cylindrical secondary battery (Comparative Examples 1 and 2) shown in FIGS. ) Was prepared to confirm the effects of the present invention. First, the steps common to each battery will be described, and then the structure of the safety valve that differs for each battery and its mounting will be described.

Preparation of Positive Electrode LiCoO ₂ (lithium composite oxide) as a positive electrode active material and carbon as a conductive agent were mixed at a weight ratio of 90: 5 to prepare a positive electrode mixture. Next, polyvinylidene fluoride as a binder was dissolved in N-methyl-2-pyrrolidone (NMP) to prepare an NMP solution. Then, the positive electrode mixture and the NMP solution are mixed so that the weight ratio of the positive electrode mixture to polyvinylidene fluoride becomes 95: 5 to prepare a slurry, and the slurry is applied to both surfaces of an aluminum foil as a positive electrode current collector. It was applied by a doctor blade method and vacuum dried at 150 ° C. for 2 hours to produce a positive electrode.

Preparation of Negative Electrode Polyvinylidene fluoride as a binder was dissolved in NMP to prepare an NMP solution, and kneaded so that the weight ratio of graphite powder having a particle diameter of 10 μm to polyvinylidene fluoride was 85:15. Prepared with slurry. This slurry was applied to both surfaces of a copper foil as a negative electrode current collector by a doctor blade method, and vacuum dried at 150 ° C. for 2 hours to produce a negative electrode.

Preparation of Electrolyte Solution LiPF ₆ was dissolved in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1 at a ratio of 1 mol / l to prepare an electrolyte solution.

The battery was assembled on the surface of the aluminum foil constituting the positive electrode to a thickness of 0.3 mm.
Welded 10 aluminum collecting tabs of 1 mm at regular intervals, and 10 nickel collecting tabs of 0.1 mm in thickness on the surface of the copper foil constituting the negative electrode. Welded. Then, the separator was sandwiched between the positive electrode and the negative electrode, and was spirally wound to form a wound electrode body. As the separator, a microporous membrane made of ion-permeable polyethylene was used. After loading the wound electrode body into a cylindrical body serving as a battery can, the positive and negative current collecting tabs extending from the wound electrode body were respectively connected to an electrode terminal mechanism attached to a lid. The lid was welded and fixed to a cylinder to assemble a cylindrical secondary battery. In addition, the cylindrical body of the battery can has an outer diameter of 60 mm, a height of 300 mm, and a thickness of 2 mm.
mm, the lid is 60 mm in diameter and 5 m in thickness
m. The height of the electrode terminal mechanism is 20 mm from the surface of the lid. The average discharge voltage of the battery is 3.6
V, the battery capacity is 70 Ah (discharge current 8.75 A).

Invention Example 1 Two screw-in safety valves (10 mm in height) each having a pressure release plate made of aluminum foil having a thickness of 50 μm were attached to the lid, and the cylindrical battery according to the present invention (the present invention) Example 1) was produced.

Inventive Example 2 Four cylindrical screw-type safety valves (height: 10 mm) each having a pressure relief plate made of nickel foil having a thickness of 5 μm were attached to the lid, and the cylindrical battery according to the present invention (the present invention) Example 2) was produced.

Invention Example 3 Four screw-in safety valves (10 mm in height) each having a pressure release plate made of copper foil having a thickness of 30 μm were attached to the lid, and the cylindrical battery according to the present invention (the present invention) Example 3) was produced.

Inventive Example 4 Two screw-in safety valves (5 mm in height) each having a pressure release plate made of stainless steel foil having a thickness of 5 μm were attached to the lid, and the cylindrical battery (the present invention) was mounted. Invention Example 4) was produced.

Comparative Example 1 ^Two return-type safety valves with a set pressure of 10 kg / cm ² were provided on the lid.
Then, a conventional cylindrical secondary battery (Comparative Example 1) was manufactured.

COMPARATIVE EXAMPLE 2 A conventional cylindrical secondary battery (Comparative Example 2) was prepared by attaching one weld-fixed safety valve having a pressure release plate made of aluminum foil having a thickness of 50 μm to a lid. .

According to the cylindrical secondary battery of the present invention, when the electrolyte is injected into the battery can in the battery assembling process, the conventional secondary battery (Comparative Example 2) shown in FIG. Although it is necessary to separately provide a hole for injecting the electrolyte, the secondary battery of the present invention can use the screw hole for screwing the safety valve formed in the cylinder, so that the configuration is simplified. Also, when assembling a battery pack using a plurality of secondary batteries, the pressure relief type safety valve as in Examples 1 to 3 of the present invention can be formed lower than the height of the electrode terminal mechanism. The work of connecting the secondary batteries to each other with the conducting wire is not hindered by the safety valve, and the assembly work becomes easier as compared with a case where a similar assembled battery is assembled using a conventional secondary battery. Further, when a battery pack is configured by connecting a plurality of secondary batteries in series, according to the present invention, compared to a case where a similar battery pack is configured 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 a perspective view illustrating a state in which a safety valve is screwed into a battery can in the cylindrical secondary battery according to the present invention.

FIG. 3 is an enlarged sectional view showing a state (a) before fastening a fixing ring and a state (b) after fastening in a safety valve according to the present invention.

FIG. 4 is a sectional view of a conventional cylindrical secondary battery provided with a return-type safety valve.

FIG. 5 is a sectional view of a conventional cylindrical secondary battery to which a pressure release type safety valve is fixed by welding.

[Explanation of symbols]

 (1) Battery can (11) Cylindrical body (12) Lid (2) Winding electrode body (3) Current collecting tab (5) Safety valve (51) Cylindrical member (52) External screw (55) Retaining ring (6) Inner clamping ring (63) Cylindrical part (7) Pressure release plate (71) Thin part (8) Outer clamping ring (82) Cylindrical part (9) Electrode terminal mechanism

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Noma 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Ikuo Yonezu 2-chome Keihanhondori, Moriguchi-shi, Osaka 5-5 Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H012 AA01 BB02 DD01 DD05 EE04 FF01 GG01 JJ03 5H029 AJ14 AK03 AL06 AM01 AM02 AM03 AM07 BJ02 BJ27 DJ02 EJ01 HJ04 HJ12

Claims (6)

[Claims] 1. A winding electrode body (2) serving as a secondary battery element is provided inside a battery can (1) having a lid (12) fixed to an opening of a cylindrical body (11) and airtight. A safety valve having a disk-shaped pressure release plate (7) that is activated when the internal pressure of a battery can (1) exceeds a predetermined value in a cylindrical secondary battery housed and stored.
A cylindrical secondary battery characterized in that (5) is screwed into a screw hole (15) opened in the lid (12). 2. A pressure relief plate (7) is provided inside a cylindrical member (51) having an external thread (52) to be screwed into a screw hole (15) of a lid (12). And a pair of clamping rings (6) and (8) for clamping the outer periphery of the pressure release plate (7), and a cylindrical member (51) is provided outside the clamping rings (6) and (8). ), A fixing ring (55) to be screwed into an internal screw (53) formed on the inner peripheral surface is arranged, and the pressure release plates (7) are provided on both the pressing rings (6) and (8).
Each of the cylindrical portions (63) and (82) protrudes toward the outer ring, and the outer diameter of the cylindrical portion (63) of one of the pressing rings (6) is equal to that of the other pressing ring.
The inner diameter of the cylindrical portion (82) of (8) is smaller than the inner diameter of the cylindrical portion (82) by a predetermined dimension.
The cylindrical secondary battery according to claim 1, wherein the thin portion (71) is formed by the pressure applied by the cylindrical portions (63) and (82) of (8). 3. A squeezing ring is provided inside the cylindrical member (51).
(6) A step (54) for receiving (8) is formed, and the cylindrical part (63) (82) clamps the outer peripheral part of the pressure release plate (7) by screwing the fixing ring (55). The cylindrical secondary battery according to claim 2. 4. An inner clamping ring (6) installed on the inner side of the battery can (1) is formed by projecting a cylindrical portion (63) on an inner peripheral portion of a disk portion (61). On the other hand, the outer clamping ring (8) arranged on the outer side of the battery can (1) is formed by projecting a cylindrical portion (82) on the inner periphery of the disk portion (81), The outer diameter of the cylindrical portion (63) of the ring (6) is smaller than the inner diameter of the cylindrical portion (82) of the outer pressing ring (8), and the outer peripheral portion of the pressure release plate (7) is connected to the outer pressing ring (8). ), And is plastically deformed along the surfaces of the disk part (61) and the cylindrical part (63) of the inner pressing ring (6), and the thin part (71) is formed by the plastic deformation. 4. The cylindrical secondary battery according to claim 2, wherein 5. The space between the disk portion (61) of the inner pressing ring (6) and the opposing surface of the step (54) of the cylindrical member (51), and the disk portion of the outer pressing ring (8). The cylindrical secondary battery according to claim 4, wherein O-rings (57) and (58) are interposed between the opposing surfaces of the pressure release plate (81) and the outer peripheral portion of the pressure release plate (7). 6. The safety valve according to claim 1, wherein the safety valve is formed to be lower than a height of a current extraction electrode terminal mechanism protruding from the lid. 4. The cylindrical secondary battery according to 1.