JP2010118339A - Valve structure, and battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve structure capable of stably exhibiting a function without having effect of a decomposed gas. <P>SOLUTION: The valve structure includes a valve body 61, and a locking structure 62 capable of extending toward a bottom face of the valve body 61 in an approximately vertical direction and being inserted into a hole as a mounting target. The locking structure 62 has a plurality of inserting sections 62b extending in the approximately vertical direction from the vicinity of the bottom face, and projection sections 62c arranged on respective tips of the plurality of inserting sections 62b and facing from the approximately vertical direction to the outside. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas vent valve and a lithium secondary battery using the gas vent valve.

  A secondary battery such as a lithium secondary battery is known as the battery. The secondary battery can be repeatedly used (discharged) by charging. When the battery is charged, used (discharged), or injected with electrolyte during the manufacturing process, the secondary battery may generate a small amount of decomposition gas. When the decomposition gas accumulates, the internal pressure of the battery container gradually increases. If such a state is left for a long period of time, the internal pressure may exceed the allowable pressure of the battery container. In addition, when an abnormality occurs in the secondary battery for some reason, the internal pressure may increase. In order to cope with such a case, a safety valve (eg, a rupture disk) is generally attached to the secondary battery. However, since such a safety valve is destroyed during operation, it cannot be used continuously after destruction.

  Further, in the secondary battery, an electrolytic solution is injected into the battery container with the battery lid welded during the manufacturing process. A battery container with a battery cover has a positive electrode and a negative electrode disposed therein, and is connected to a positive electrode terminal and a negative electrode terminal provided on the battery cover, respectively. The electrolyte is injected from the inlet of the battery lid. After injecting the electrolyte, the container is sealed by closing the inlet with a sealing plug. Thereby, the basic configuration of the secondary battery is completed.

  A gas release valve (gas vent valve) provided for the purpose of keeping the internal pressure of the secondary battery within a range not exceeding the allowable pressure of the battery container is disclosed in Patent Document 1. The gas release valve of the solid-type chromium-fluorine-lithium secondary battery of Patent Document 1 includes an upper body portion including a gas discharge hole, a rubber piece, and a base plate provided with a gas discharge hole. When the internal gas pressure of the gas generated from the electrolyte solvent exceeds a predetermined level, the gas from the gas discharge hole applies an upward pressure to the bottom surface of the rubber piece. As a result, the gas overhangs the rubber piece and reaches the upper body portion through a gap left between the annular edge of the rubber piece and the base plate. Then, the gas flows out to the external environment through the gas discharge hole in the upper body portion.

Japanese Patent Laid-Open No. 2001-210379

  Although the method for attaching the gas release valve (gas vent valve) to the battery lid is not disclosed in Patent Document 1, for example, in order to face the internal pressure, any of a technique such as laser welding, a valve and a battery lid is used. A method of providing a male screw structure on one side and a female screw structure on the other is conceivable. Here, a technique such as laser welding is laborious, time-consuming, and costly. Further, in the method using the screw structure, when the engagement between the male screw structure and the female screw structure is poor, there is a possibility that chips are generated. In that case, there is a concern that the chips may be adversely affected on the performance and safety of the battery due to the chips inside the battery. There is a demand for a technique that does not require time, cost, and cost and does not affect the performance and safety of the battery.

  In addition, the gas release valve (gas vent valve) may cause the surface of the rubber piece to be deformed due to corrosion or the like when the decomposition gas is released, or the rubber piece may be suddenly deformed by a gas having a high flow velocity. Conceivable. If such deformation occurs even at one location, the rubber piece has a thin film shape, so that it is difficult for the force to correct the deformation to work and the deformation remains as it is. As a result, a gap is formed between the rubber piece and the base plate, and there is a possibility that gas leaks at all times, and it is considered that the function as a gas release valve cannot be performed. A technology that can stably function without being affected by cracked gas is desired.

  Furthermore, as a method of attaching the sealing plug to the battery lid, a screw attachment method in which either one of the sealing plug or the battery lid is provided with a male screw structure and the other is provided with a female screw structure. However, such a screw mounting method has the following drawbacks. That is, there is a possibility that metal chips are generated when the engagement between the male screw structure and the female screw structure is poor at the time of screw tightening. In that case, there is a risk that the metal chips are mixed into the battery, leading to a decrease in battery performance and safety. Moreover, in order to suppress generation | occurrence | production of the metal chip, the method of making a screw into resin is also considered. However, there is a risk that the screw will be damaged when the screw is tightened due to insufficient strength of the screw thread. In addition, in the case of the screw mounting method, tightening torque management is required in the manufacturing process, which increases the number of processes. Therefore, a technique that does not take time and effort for the sealing plug and does not affect the performance and safety of the battery is desired.

  The objective of this invention is providing the valve structure which can exhibit a function stably without being influenced by decomposition gas, and a battery using the same.

  Another object of the present invention is to provide a valve structure that does not require labor, time, and cost and does not affect the performance and safety of the battery, and a battery using the valve structure.

  Still another object of the present invention is to provide a sealing plug as a kind of degassing valve that does not take time and effort and does not affect the performance and safety of the battery, and a battery using the sealing plug. It is in.

  These objects and other objects and advantages of the present invention can be easily confirmed by the following description and attached drawings.

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the embodiments for carrying out the invention. These numbers and symbols are added with parentheses in order to clarify the correspondence between the description of the claims and the mode for carrying out the invention. However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.

The gas vent valve as the valve structure of the present invention includes a main body (31) and a locking structure (32). The locking structure (32) extends in a direction substantially perpendicular to the bottom surface of the main body (31) and can be inserted into a hole to be attached. The locking structure (32) includes a plurality of insertion portions (32b) and a plurality of protrusions (32c). The plurality of insertion portions (32b) extend in a substantially vertical direction from the periphery of the opening (35) provided on the bottom surface of the main body (31). The protrusion (32c) is provided at the tip of each of the plurality of insertion portions (32b) and faces outward from the substantially vertical direction.
If the gas vent valve of the present invention is used, the protrusion (32c) can be formed by inserting the locking structure (32) into the hole to be attached without using a technique such as laser welding or a technique using a screw structure. It is caught in the hole, and the gas vent valve can be attached to the attachment target very easily. As a result, it is possible to greatly reduce the labor, time and cost of attaching the secondary battery to the battery lid (2), etc., and to adversely affect the performance and safety of the battery due to the generation of chips. It can be avoided.

In the above vent valve, the locking structure (32) contains a resin.
In the present invention, the locking structure (32) is formed of resin. Therefore, when the locking structure (32) is inserted into the hole to be attached, the surface of the locking structure (32) is difficult to be scraped. Therefore, it can prevent that shavings generate | occur | produce.

In the gas vent valve, the elastic member (34) opens the seal when gas having a predetermined pressure or more is in contact with the opening (35), and gas is released from the opening (35) to the gas vent hole (33). Deforms so that it comes off.
The gas vent valve of the present invention uses a three-dimensional elastic member (34) and performs gas venting by deformation thereof. Therefore, even if the surface is affected by corrosion, etc., or part of it is subjected to abrupt deformation by a gas with a high flow velocity, the influence of the corrosion and deformation is compared with the film shape (two-dimensional shape). It is extremely small and does not cover the whole. Thereby, it becomes possible to exhibit the function as a gas vent valve stably and continuously without being influenced by the cracked gas.

In the gas vent valve, the elastic member (34) includes a bottom portion (34a), a side surface portion (34b), and an upper end portion (34c). The bottom (34a) covers the opening (35). The side surface part (34b) is connected around the bottom part (34a) and provided so as to rise from the bottom part (34a). The upper end (34c) is connected to the end of the side surface (34b) and is held by the gas vent valve body (31).
In the elastic member (34) of the present invention, the upper end (34c) fixes the basic position, the bottom (34a) is in direct contact with the gas to close the opening (35), and the side (34b) is the bottom ( The position change of 34a) is controlled by its own deformation. As a result, compared to a simple two-dimensional elastic membrane, the effect of corrosion and deformation is extremely small, and it can function stably and continuously without being affected by the cracked gas. It becomes possible.

In the gas vent valve, the elastic member (34A) has a solid cylindrical shape that covers the opening (35) at the bottom surface and the top surface is pressed by the gas vent valve body (31).
In the elastic member (34A) of the present invention, the upper surface portion fixes the basic position of the whole, the bottom surface portion closes the opening (35), and as a whole deforms itself, the position change of the bottom surface portion is controlled. ing. As a result, compared to a simple two-dimensional elastic membrane, the effect of corrosion and deformation is extremely small, and it can function stably and continuously without being affected by the cracked gas. It becomes possible.

The secondary battery of the present invention includes a secondary battery body (2, 3) and a gas vent valve (6). The secondary battery body includes a battery container (3) and a battery lid (2) provided on the battery container (3). The gas vent valve (6) is mounted in the gas vent valve mounting hole (23) of the battery lid (2) and is described in any of the above paragraphs. In the gas vent valve (6), a plurality of insertion portions (32b) are inserted into the gas vent valve mounting hole (23), and locked to the gas vent valve mounting hole (23) by the protrusion (32c).
The secondary battery of the present invention is stable without being affected by the degassing valve (6) which does not affect the performance and safety of the battery and the decomposition gas because it does not take time, cost and cost as described above. It uses a vent valve that can function continuously and continuously. As a result, when a pressure increase occurs, the gas vent valve (6) can appropriately remove high-pressure gas, and a lithium secondary battery that is highly reliable and excellent in safety can be obtained.

In the above secondary battery, the gas vent valve mounting hole (23) is recessed toward the inside of the battery container (3).
In the present invention, the gas vent valve mounting hole (23) of the battery lid (2) is recessed. Thereby, the locking structure (32) can be easily mounted by sliding in the recess. Moreover, when the pressure in a battery container (3) rises, it can make it hard to remove | eliminate a gas vent valve (6) by relieving a pressure in a hollow part.

In the above secondary battery, the predetermined pressure is lower than the set pressure in the safety valve (11) provided on the battery lid and opened irreversibly at a set pressure or higher.
In the present invention, sudden and high pressure changes are dealt with by an irreversible method using the safety valve (11), while at a pressure lower than the set pressure of the safety valve (11), the gas vent valve (6) is used repeatedly and continuously. Can be dealt with in a way that is compatible with That is, when a pressure increase occurs, it can be dealt with by the gas vent valve (6) before an emergency situation (a situation where the safety valve (11) is used). As a result, it is possible to extend the usable period of the secondary battery while maintaining safety and reliability.

The vent valve of the present invention comprises a vent valve main body (31) and a locking structure (32). The gas vent valve body (31) includes an internal space (A, B) having an opening (35) on the bottom surface and a gas vent hole (33) on the other surface, and seals the opening (35). The member (34) is provided in the internal space (A, B). The locking structure (32) is provided on the bottom surface and can be attached to a hole to be attached. The elastic member (34) has a three-dimensional shape, opens the seal when a gas having a predetermined pressure or more comes into contact with the opening (35), and gas is released from the opening (35) to the gas vent hole (33). Deforms so that it comes off.
The gas vent valve of the present invention uses a three-dimensional elastic member (34) and performs gas venting by deformation thereof. Therefore, even if the surface is affected by corrosion, etc., or part of it is subjected to abrupt deformation by a gas with a high flow velocity, the influence of the corrosion and deformation is compared with the film shape (two-dimensional shape). It is extremely small and does not cover the whole. Thereby, it becomes possible to exhibit the function as a gas vent valve stably and continuously without being influenced by the cracked gas.

In the gas vent valve, the elastic member (34) includes a bottom portion (34a), a side surface portion (34b), and an upper end portion (34c). The bottom (34a) covers the opening (35). The side surface part (34b) is connected around the bottom part (34a) and provided so as to rise from the bottom part (34a). The upper end portion (34c) is connected to the end portion of the side surface portion (34b) and is held by the gas vent valve main body (31).
In the elastic member (34) of the present invention, the upper end (34c) fixes the basic position, the bottom (34a) is in direct contact with the gas to close the opening (35), and the side (34b) is the bottom ( The position change of 34a) is controlled by its own deformation. As a result, compared to a simple two-dimensional elastic membrane, the effect of corrosion and deformation is extremely small, and it can function stably and continuously without being affected by the cracked gas. It becomes possible.

In the gas vent valve, the elastic member (34A) has a solid cylindrical shape that covers the opening (35) at the bottom surface and the top surface is pressed by the gas vent valve body (31).
In the elastic member (34A) of the present invention, the upper surface portion fixes the basic position of the whole, the bottom surface portion closes the opening (35), and as a whole deforms itself, the position change of the bottom surface portion is controlled. ing. As a result, compared to a simple two-dimensional elastic membrane, the effect of corrosion and deformation is extremely small, and it can function stably and continuously without being affected by the cracked gas. It becomes possible.

The secondary battery of this invention comprises a secondary battery main body and a gas vent valve (6). The secondary battery body includes a battery container (3) and a battery lid (2) provided on the battery container (3). The gas vent valve (6) includes the gas vent valve (6) according to any one of the above paragraphs mounted in the gas vent valve mounting hole (23) of the battery lid (2). The gas vent valve (6) is attached to the gas vent valve mounting hole (23) with a locking structure (32).
The secondary battery of the present invention uses a gas vent valve as described above, which can stably function without being affected by the cracked gas. As a result, when a pressure increase occurs, the gas vent valve (6) can appropriately remove high-pressure gas, and a lithium secondary battery that is highly reliable and excellent in safety can be obtained.

The sealing plug as the valve structure of the present invention includes a sealing plug body (61) and a locking structure (62). The locking structure (62) extends in a direction substantially perpendicular to the bottom surface of the sealing plug body (61) and can be inserted into a hole to be attached. The locking structure (62) includes a base portion (62a), a plurality of insertion portions (62b), and a protruding portion (62c). The base portion (62a) extends from the bottom surface in a substantially vertical direction. The plurality of insertion portions (62b) extend in a substantially vertical direction from the base portion (62a). The protrusion (62c) is provided at the tip of each of the plurality of insertion portions (62b) and faces outward.
When the sealing plug of the present invention is used, the protrusion (62c) is caught in the hole by inserting the locking structure (62) into the hole to be attached, so that a screw attachment method using a screw structure is not used. The sealing plug can be attached to the attachment target very easily. For sealing, after the base portion (62a) is surrounded by an O-ring or gasket, the locking structure (62) is inserted into the hole so that the sealing plug body (61) is attached to the O-ring or gasket. This can be realized by pressing the object. Alternatively, a method of filling a space between the attachment target and the locking structure (62) with a sealant or an adhesive can be used. As a result, it is possible to greatly reduce the labor and time for attaching the sealing plug to the battery cover (2) of the secondary battery, etc., and adversely affect the performance and safety of the battery due to the generation of chips. This can be avoided.

In the above sealing plug, the locking structure (62) contains a resin.
In the present invention, the locking structure (32) is formed of resin. Therefore, when the locking structure (32) is inserted into the hole to be attached, the surface of the locking structure (32) is difficult to be scraped. Therefore, it can prevent that shavings generate | occur | produce.

The secondary battery of the present invention includes a secondary battery body (2, 3) and a sealing plug (56). The secondary battery body (2, 3) includes a battery container (3) and a battery lid (2) provided on the battery container (3). The sealing plug (56) is mounted in the sealing plug mounting hole (28) of the battery lid (2) and is described in any of the above paragraphs. In the sealing plug (56), a plurality of insertion portions (62b) are inserted into the sealing plug mounting hole (28), and locked to the sealing plug mounting hole (28) by the protrusions (62c).
The secondary battery of the present invention uses the sealing plug (56) which does not take time and effort and does not affect the performance and safety of the battery as described above. Accordingly, a secondary battery that is easy to manufacture, reliable, and excellent in safety can be obtained.

The secondary battery further includes a sealing material (18) disposed between the battery lid (2) and the base (62a).
In the secondary battery of the present invention, since the sealant (18) is used, it is possible to reliably prevent the electrolyte solution and the decomposition gas from leaking from the battery container (3).

In the above secondary battery, the sealing material (18) is an O-ring (18) attached so as to surround the base portion (62a).
In the secondary battery of the present invention, since the O-ring (18) is used as the sealant (18), leakage can be prevented more reliably.

In the above secondary battery, the sealing plug mounting hole (28) is recessed toward the inside of the battery container (3).
In the present invention, the sealing plug mounting hole (28) of the battery lid (2) is recessed. Thereby, the locking structure (62) can be easily mounted by sliding in the recess.

  According to the present invention, it is possible to provide a gas vent valve and a lithium secondary battery using the gas vent valve that do not require labor, time, and cost and do not affect the performance and safety of the battery. In addition, it is possible to provide a gas vent valve that can function stably without being affected by the cracked gas and a lithium secondary battery using the gas vent valve. Further, it is possible to provide a sealing plug and a lithium secondary battery using the sealing plug that do not require time and effort and do not affect the performance and safety of the battery.

FIG. 1 is a top view showing a schematic configuration of a lithium secondary battery according to first and second embodiments of the present invention. FIG. 2 is a front view showing a schematic configuration of the lithium secondary battery according to the first and second embodiments of the present invention. FIG. 3 is a schematic diagram showing a schematic internal configuration of the lithium secondary battery according to the embodiment of the present invention. FIG. 4 is a schematic diagram showing the configuration of the gas vent valve according to the embodiment of the present invention. FIG. 5A is a cross-sectional view showing an example of a schematic configuration of a gas vent valve according to an embodiment of the present invention. FIG. 5B is a cross-sectional view showing an example of a schematic configuration of the gas vent valve according to the embodiment of the present invention. FIG. 5C is a schematic diagram illustrating an example of a schematic configuration of the elastic member according to the embodiment of the present invention. FIG. 6A is a cross-sectional view showing another example of the schematic configuration of the gas vent valve according to the embodiment of the present invention. FIG. 6B is a cross-sectional view showing another example of the schematic configuration of the gas vent valve according to the embodiment of the present invention. FIG. 6C is a schematic diagram illustrating another example of the schematic configuration of the elastic member according to the embodiment of the present invention. FIG. 7 is a schematic view showing a configuration of a gas vent valve according to another embodiment of the present invention. FIG. 8 is a top view showing a schematic configuration of a lithium secondary battery according to the third embodiment of the present invention. FIG. 9 is a front view showing a schematic configuration of a lithium secondary battery according to the third embodiment of the present invention. FIG. 10 is a schematic diagram showing a configuration of a sealing plug according to a third embodiment of the present invention. FIG. 11 is a schematic diagram showing a configuration of a sealing plug according to the third embodiment of the present invention. FIG. 12 is a schematic diagram showing a configuration of a sealing plug according to the third embodiment of the present invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a lithium secondary battery using the gas vent valve and the gas vent valve of the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
1 and 2 are a top view and a front view showing a schematic configuration of a lithium secondary battery according to an embodiment of the present invention. The lithium secondary battery 1 includes a battery lid 2 and a battery container 3.

  The battery lid 2 is a lid for sealing the battery container 3 and is formed of, for example, a steel material such as stainless steel or an aluminum-based material. The battery cover 2 includes a positive electrode terminal 4, a negative electrode terminal 5, insulators 14 and 15, a gas vent valve 6, and a safety valve 11.

  The positive electrode terminal 4 is an extraction terminal for a positive electrode, and is attached to the battery lid 2 via an insulator 14. The positive electrode terminal 4 is made of aluminum, for example, and is connected to the positive electrode (described later) inside the battery container 3. The positive electrode terminal 4 may cover the outer surface of the battery container 3 with, for example, nickel plating in order to reduce contact resistance. The negative electrode terminal 5 is a takeout terminal for a negative electrode, and is attached to the battery lid 2 via an insulator 15. The negative electrode terminal 5 is made of, for example, copper, and is connected to a negative electrode (described later) inside the battery container 3.

  The gas vent valve 6 opens the gas in the battery container 3 to the outside when the pressure in the battery container 3 becomes equal to or higher than a predetermined pressure. That is, the gas vent valve 6 can be continuously used and has a function of keeping the internal pressure of the lithium secondary battery 1 within a range that does not exceed the allowable pressure of the battery container 3. The configuration of the gas vent valve 6 will be described later. The gas vent valve 6 is mounted in a gas vent valve mounting hole (described later) of the battery lid 2. As the degassing valve mounting hole, an injection hole for injecting an electrolytic solution (described later) into the battery container 3 can be used. That is, the injection hole can be sealed with a gas vent valve. Further, in the figure, the gas vent valve 6 is provided at one end of the battery lid 2, but may be provided at the other end. Furthermore, it is more preferable to provide at a position on a diagonal line. This is because any of the gas vent valves 6 can perform the function of venting even when the battery container 3 is used in a state where the battery container 3 is tilted sideways.

  The safety valve 11 bursts when the pressure in the battery container 3 suddenly rises, and releases the pressure in the battery container 3. The safety valve 11 is exemplified by a rupture disk. Thereby, it can prevent that the whole battery container 3 bursts. However, since it bursts, it cannot be reused. The safety valve 11 is provided at a substantially central portion of the battery lid 2 and is formed of a metal material such as aluminum, for example.

  The battery container 3 is a container for storing a battery main body, and is formed of, for example, a steel material such as stainless steel or an aluminum-based material. The inner surface of the battery container 3 may be in direct contact with the electrolytic solution, but may be covered with an insulating film such as a modified polyolefin.

  FIG. 3 is a schematic diagram showing a schematic internal configuration of the lithium secondary battery according to the embodiment of the present invention. The battery container 3 includes an electrolytic solution 7, a positive electrode 8, and a negative electrode 9.

The electrolytic solution 7 is a non-aqueous electrolytic solution containing lithium ions (example: an organic solvent such as ethylene carbonate or diethyl carbonate + a lithium salt such as lithium hexafluorophosphate (LiPF ₆ )). The positive electrode 8 is configured, for example, by applying lithium manganate (LiMn ₂ O ₄ ) capable of inserting and extracting lithium ions as a positive electrode active material on the surface of a main body made of aluminum foil or the like. The positive electrode terminal 4 is connected to the upper part. The negative electrode 9 is made of, for example, carbon or graphite. The negative electrode terminal 5 is connected to the upper part. A plurality of positive electrodes 8 and negative electrodes 9 are alternately arranged, and a separator is inserted between them. The separator is made of, for example, a porous polymer film such as polyethylene or polypropylene, a non-woven fabric made of glass fiber or polymer fiber, or the like.

  Note that the configuration of the lithium secondary battery is an example, and other configurations can be used without departing from the technical idea of the present invention.

  Next, the configuration of the gas vent valve 6 will be described. FIG. 4 is a schematic diagram showing the configuration of the gas vent valve according to the embodiment of the present invention. The gas vent valve 6 includes a gas vent valve main body 31 and a locking structure 32. The gas vent valve 6 is fitted in a gas vent valve mounting hole (gas vent hole) 23 provided in the battery lid 2 by a locking structure 32 via a sealing material such as an O-ring 16.

  The gas vent valve main body 31 has an elastic member 34 (described later) inside, a first hole 35 (described later) on the bottom surface, and a second hole 33 on the side surface or top surface. In the example of FIG. 4, the second hole 33 is provided on the side surface. When the pressure in the battery container 3 becomes equal to or higher than a predetermined pressure, the gas vent valve main body 31 is deformed by the elastic member 34 that closes the first hole 35 to open the first hole 35, the first hole 35, the gas The gas in the battery container 3 is opened to the outside through the inside of the drain valve main body 31 and the second hole 33. The gas vent valve body 31 has a cylindrical shape. A center line C in FIG. 4 passes through the centers of the gas vent valve main body 31 and the first hole 35. The internal structure will be described later.

  The locking structure 32 is provided on the bottom surface of the gas vent valve main body 31 and extends in a substantially vertical direction (a downward direction along the center line C in FIG. 4) from the periphery of the first hole 35 on the bottom surface. The locking structure 32 is inserted and fitted into the gas vent valve mounting hole 23 of the battery lid 2. Thereby, the gas vent valve 6 is fixed to the battery lid 2. A center line C in FIG. 4 also passes through the centers of the locking structure 32 and the gas vent valve mounting hole 23. The locking structure 32 includes a base portion 32a, a plurality of insertion portions 32b, and a protruding portion (return) 32c.

  The base portion 32 a is provided on the bottom surface of the gas vent valve main body 31 so as to surround the first hole 35. In the case of FIG. 4, it has a thick cylindrical shape surrounding the first hole 35. Since the O-ring 16 is in close contact with the periphery of the base portion 32a, the sealing performance by the O-ring 16 is further improved. A plurality of insertion portions 32 b are provided on the surface of the base portion 32 a so as to surround the first hole 35. And the insertion part 32b is extended in the substantially perpendicular | vertical direction (downward direction along the centerline C of FIG. 4) from the base | substrate part 32a. Since the end of the insertion portion 32b opposite to the base portion 32a is not fixed, it can swing. In the case of FIG. 4, the shape which divided the cylinder into four, ie, the four insertion parts 32b, are provided on the base | substrate part 32a. However, the number of insertion parts 32b is not limited to four. The protrusion 32c is a protrusion that is provided at an end of each insertion portion 32b opposite to the base portion 32a and extends outward with respect to the center line C.

  The outer diameter d1 of the circle surrounding the outside of the plurality of insertion portions 32b is substantially equal to or more preferably slightly larger than the inner diameter D1 of the gas vent valve mounting hole 23. As a result, shake and backlash in a direction parallel to the surface of the battery lid 2 can be suppressed. Further, the outer diameter d2 of the circle surrounding the outside of the plurality of protrusions 32c is larger than the inner diameter D1 of the gas vent valve mounting hole 23. Thereby, the gas vent valve 6 is locked in the gas vent valve mounting hole 23, and it is possible to prevent the gas vent valve 6 from being detached from the gas vent valve mounting hole 23. Further, the length t1 to the base of the protrusion 32c in the locking structure 32 (the length to the base of the protrusion 32c of the base portion 32a + the insertion portion 32b) is determined by venting the gas vent valve 6 via the O-ring 16. When fitted in the valve mounting hole 23, the lower part of the gas vent valve body 31 is moderately pressed against the O-ring 16. Accordingly, the O-ring 16 can appropriately perform sealing.

  The gas vent valve main body 31 and the locking structure 32 are made of resin (example: plastics). The resin is preferably a resin having high corrosion resistance, high strength, and a certain degree of elasticity. For example, a thermoplastic resin. More preferably, it is an engineering plastic having relatively high strength and corrosion resistance. Engineering plastics are exemplified by polycarbonate (PC), polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). More preferably, it is a super engineering plastic having higher strength and corrosion resistance. Super engineering plastics include polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyether ether Examples are ketone (PEEK), thermoplastic polyimide (PI), and polyamideimide (PAI). More preferred is polyphenylene sulfide (PPS).

  The battery lid 2 is preferably recessed toward the inside of the battery container 3 in the gas vent valve mounting hole 23. That is, the battery lid 2 preferably has a flat plate portion 21 and a recess 22 that is connected to the flat plate portion 21 and that is recessed toward the inside of the battery container 3. The reason is as follows. The recess 22 has an inner diameter that gradually decreases (squeezes) from the outside to the inside of the battery container 3. Therefore, when the gas vent valve 6 is installed in the gas vent valve mounting hole 23, the recess portion 22 becomes narrowed as the insertion portion 32 b and the projection portion 32 c of the locking structure 32 are inserted into the recess portion 22. Along the direction toward the center line C, it is guided and elastically deformed easily. As a result, the locking structure 32 (outer diameter d2) can be easily entered into the gas vent valve mounting hole 23 (inner diameter D1 <d2). When the protrusion 32 c is inserted into the gas vent valve mounting hole 23 at the tip of the recess 22, the protrusion 32 c is released from the restriction of the recess 22. Thereby, the elastic deformation of the insertion portion 32b is released and the state returns to the original state. At that time, the protrusion 32 c enters the gas vent valve mounting hole 23 and is caught by the inner peripheral portion of the gas vent valve mounting hole 23. This state is shown in FIG. A shape such as the depression 22 can be produced by, for example, press working.

  Furthermore, after the degassing valve 6 is mounted, the degassing valve 6 is mounted in the degassing valve mounting hole 23 only by being caught in the inner peripheral portion of the degassing valve mounting hole 23 by the protrusion 32c. Become. At this time, when the pressure of the gas in the battery container 3 rises, the recess 22 can relieve the pressure applied to the portion where the protrusion 32c is caught by the effect of elastic deformation on the curved surface. Thereby, the degassing valve 6 can be made more difficult to come off with respect to the increase in the gas pressure in the battery container 3.

  As shown in FIG. 4, the angle α formed by the lower surface of the protrusion 32c and the surface parallel to the center line C of the insertion portion 32b is preferably smaller than 90 degrees. More preferably, it is in the range of 30 to 60 degrees. This is because the resistance when the protrusion 32c slides on the recess 22 is reduced. Further, the angle β formed by the end of the battery lid 2 on the side of the gas vent valve mounting hole 23 and the upper surface of the protrusion 32c is preferably in the range of 30 to 60 degrees. More preferably, it is 40 to 50 degrees. The protrusion 32c is appropriately fixed at the end of the battery lid 2 so that the gas release valve 6 does not come off against the internal pressure of the battery container 3, and the gas release valve 6 can be removed with a certain degree of pulling force (replacement). This is to make it possible. If the “a certain degree of strength” is set to the same level as the pressure at which the safety valve 11 bursts, for example, the function of the safety valve 11 can be performed at the same time.

  When the gas vent valve 6 is inserted into the gas vent valve mounting hole 23, the gas vent valve 6 is inserted together with the sealing material exemplified by the O-ring 16. The O-ring (seal material) 16 is elastically deformed by being sandwiched between the upper surface of the recess 22 and the bottom surface of the gas vent valve body 31. Thereby, the gas inside the battery container 3 can be isolated from the outside with the flat plate portion 21, the recessed portion 22, the O-ring 16, and the gas vent valve body 31 (bottom surface) of the battery lid 2 as boundaries. As a result, even if there is a gap through which gas can flow between the insertion portion 32b (protrusion portion 32c) of the gas vent valve 6 and the gas vent valve mounting hole 23 of the battery lid 2, gas leakage can be prevented. And the gas inside battery container 3 does not leak outside except gas vent valve 6 or safety valve 11.

  Next, the internal structure of the gas vent valve 6 will be described. 5A to 5C are a cross-sectional view and a schematic view showing an example of a schematic configuration of the gas vent valve according to the embodiment of the present invention. The gas vent valve main body 31 includes an upper gas vent valve main body 31a, a lower gas vent valve main body 31b, and an elastic member 34.

  Referring to FIG. 5A, the lower gas vent valve main body 31b has a cylindrical container shape, and has a first hole 35 on the bottom surface and a second hole 33 on the side surface. The upper gas vent valve main body 31a has a cylindrical lid shape, has a second hole 33 on a side surface, and covers the lower gas vent valve main body 31b from above. The upper gas vent valve main body 31a and the lower gas vent valve main body 31b may be coupled by, for example, a male screw structure / female screw structure, or may be coupled by an adhesive.

  The elastic member 34 has a bowl shape and is stored in a space formed between the upper gas vent valve main body 31a and the lower gas vent valve main body 31b. Since there are empty spaces A and B on the upper and lower sides of the bowl shape, the elastic member 34 can be deformed in the spaces A and B. The elastic member 34 is deformed to open the first hole 35 when the pressure in the battery container 3 becomes equal to or higher than a predetermined pressure, and passes through the first hole 35, the gas vent valve main body 31 and the second hole 33. Then, the gas in the battery container 3 is released to the outside. The elastic member 34 includes a bottom portion 34a, a side surface portion 34b, and an upper end portion 34c. A schematic perspective view showing the shape of the elastic member 34 is shown in FIG. 5C.

  Since the bottom portion 34a is disposed at a position closing the first hole 35, the gas of the battery container 3 is in contact therewith. Moreover, when the pressure of the battery container 3 rises, high-pressure gas comes into contact. Therefore, it has a certain thickness so as not to lose the gas. The side surface portion 34b is connected to the periphery of the bottom portion 34a and is provided so as to rise from the bottom portion 34a. When the bottom portion 34a is flipped up by the gas pressure of the battery case 3, the magnitude of the jumping pressure is defined by the elastic force and shape. And it functions so that the bottom part 34a which bounces up once may be returned by the elastic force. The upper end 34c is fitted and fixed between the upper gas vent valve main body 31a and the lower gas vent valve main body 31b. By firmly fixing the upper end portion 34c, even if the bottom portion 34a and the side surface portion 34b move or deform, the elastic member 34 finally returns to its original position and shape by its own elastic force. I can do it. As described above, the elastic member 34 includes an upper end 34c that fixes the basic position of the whole, a bottom 34a that closes the first hole 35, and a side part 34b that controls the position change of the bottom 34a by deforming itself. It consists of and.

  The elastic member 34 is made of an elastic material. The elastic material is preferably a material that has high corrosion resistance and can be deformed by a predetermined gas pressure. An example is synthetic rubber. Synthetic rubbers are exemplified by diene rubbers such as hydrogenated nitrile rubber and chloroprene rubber, and non-diene rubbers such as ethylene propylene rubber, ethylene propylene diene rubber (EPDM) rubber and fluoro rubber. More preferred is ethylene propylene diene rubber. The shape and material (especially the elastic coefficient) of the elastic member 34 are determined experimentally or simulationally, for example, corresponding to the set pressure for degassing required for the degassing valve 6.

  FIG. 5B is a schematic cross-sectional view showing a state in which gas is extracted through the gas release valve 6. When the pressure of the gas in the battery container 3 increases, the pressure on the bottom 34a covering the first hole 35 increases. When the pressure overcomes the elastic force of the side surface portion 34b, the side surface portion 34b is deformed and the bottom portion 34a jumps up. As a result, the gas in the battery container 3 passes through the first hole 35, the space B, and the second hole 33 and is sent to the outside. Thereafter, when the pressure of the gas in the battery container 3 decreases and the elastic force of the side surface portion 34b is overcome, the side surface portion 34b returns to its original position, and the bottom portion 34a covers the first hole 35 again.

  In this way, the pressure of the gas in the battery container 3 is maintained at a predetermined pressure. The predetermined pressure can be set in a desired range depending on the material type and shape of the elastic member 34 (including the thickness of each part). In that case, continuous use is possible, and the internal pressure of the lithium secondary battery 1 is set in a range not exceeding the allowable pressure of the battery container 3, that is, lower than the set pressure in the safety valve 11. For example, if the set pressure of the safety valve 11 is 0.5 MPa, the set pressure of the gas vent valve 6 can be set to 0.05 MPa to 0.1 MPa.

  In the example of FIGS. 5A to 5C, the elastic member 34 has a bowl shape. However, the elastic member is not limited to its shape, and when the pressure in the battery container 3 becomes equal to or higher than a predetermined pressure, the elastic member is deformed to open the first hole 35, and the first hole 35, the gas vent valve. Any shape that can open the gas in the battery container 3 to the outside through the inside of the main body 31 and the second hole 33 may be used.

  6A to 6C are a cross-sectional view and a schematic view showing another example of the schematic configuration of the gas vent valve according to the embodiment of the present invention. Compared to the case of FIGS. 5A to 5C, the configuration of the elastic member 34A is different.

  Referring to FIG. 6A, the elastic member 34A has a substantially cylindrical (solid, bulk shape) shape and is stored in a space formed between the upper gas vent valve main body 31a and the lower gas vent valve main body 31b. Has been. Since there are empty spaces E and D on the side or part of the upper side of the solid cylinder, the elastic member 34A can be deformed in the spaces E and D. The elastic member 34 </ b> A is deformed to open the first hole 35 when the pressure in the battery container 3 becomes equal to or higher than a predetermined pressure, and the first hole 35, the gas vent valve body 31 and the second hole 33 are interposed. Then, the gas in the battery container 3 is released to the outside. The elastic member 34A is fixed on the upper surface of the solid cylinder. In this case, the elastic member 34 controls the positional change of the bottom surface portion by fixing the basic position of the entire upper surface portion, closing the first hole 35 by the bottom surface portion, and deforming itself as a whole. The material of the elastic member 34A is the same as that of the elastic member 34A. A schematic perspective view showing the shape of the elastic member 34A is shown in FIG. 6C.

  FIG. 6B is a schematic cross-sectional view showing a state where gas is extracted through the gas vent valve 6. When the pressure of the gas in the battery container 3 increases, the pressure on the bottom surface of the solid cylinder covering the first hole 35 increases. When the pressure overcomes the elastic force of the solid cylinder, mainly the lower part and the periphery of the side part of the solid cylinder are deformed, and the bottom surface jumps up. As a result, the gas in the battery container 3 passes through the first hole 35, the space E, and the second hole 33 and is sent to the outside. After that, when the pressure of the gas in the battery container 3 decreases and the elastic force of the solid cylinder overcomes, the deformed portions such as the lower part and the side part of the solid cylinder return to the original, and the bottom surface covers the first hole 35 again. In this way, the pressure of the gas in the battery container 3 is maintained at a predetermined pressure.

  In addition to the solid cylindrical shape as in the examples of FIGS. 6A to 6C, the gas is contained in the gas vent valve body 31 (cylindrical container) and the gas between the first hole 35 and the second hole 33 is not contained. The shape may be a shape that blocks distribution, for example, a shape like a spheroid that is flat vertically. Alternatively, the cylindrical shape or the spheroid shape may be hollow. In that case, deformation becomes easy.

  The gas vent valve according to the present embodiment can be attached to the battery lid very easily with a locking structure without using a technique such as laser welding or a technique using a screw structure. As a result, it is possible to greatly reduce labor, time and cost with respect to attachment to the battery lid, and to avoid adversely affecting the performance and safety of the battery due to the generation of chips.

  In addition, the gas vent valve according to the present embodiment has a three-dimensional structure such as a bowl shape or a solid cylinder shape, not an elastic member having a thin film shape (two-dimensional shape). Yes. Therefore, even if the surface of the elastic member is somewhat corroded or receives a gas having a high flow rate, it is difficult to be deformed and the shape can be maintained. Accordingly, it is possible to stably function as a gas release valve without being influenced by the gas in the battery container.

(Second Embodiment)
In the above-described embodiment, the structure of the gas vent valve 6 has the locking structure 32 at the lower part of the gas vent valve main body 31. However, when a screw structure may be used (example: a material that does not easily generate chips or a material that does not affect the battery characteristics even if it is generated), the screw structure is changed to a locking structure. May be used.

  FIG. 7 is a schematic view showing a configuration of a gas vent valve according to another embodiment of the present invention. The gas vent valve 6A includes a gas vent valve main body (gas vent valve main body) 31 and a screw structure 32A. The gas vent valve 6 </ b> A is fitted into a gas vent valve mounting hole (gas vent hole) 23 </ b> A provided in the battery lid 2 with a screw structure 32 </ b> A via a sealing material such as an O-ring 16. The screw structure 32 </ b> A of the gas vent valve 6 </ b> A is different from the locking structure in that the screw structure 32 </ b> A hardly deviates due to the pressure inside the battery container 3. Removal (exchange) can be easily performed by screw rotation.

  Since the gas vent valve main body 31 is the same as that of the first embodiment (FIGS. 4, 5A to 5C, and FIGS. 6A to 6C), the description thereof is omitted. The screw structure 32A is a male screw structure provided on the bottom surface of the gas vent valve body 31, and extends from the bottom surface in a substantially vertical direction. The screw structure 32A is provided with a flow path (not shown) communicating with the first hole 35 (not shown). Thereby, the gas in the battery container 3 is in contact with the first hole 35. The screw structure 32 </ b> A is screwed with a female screw structure 22 </ b> A provided in the gas vent valve mounting hole 23 of the flat plate portion 21 of the battery lid 2.

  The screw structure 32A is made of a resin (eg, plastics) as a material that hardly generates chips or a material that does not affect the battery characteristics even when the chips are generated. The resin is preferably a resin having high corrosion resistance, high strength, and a certain degree of elasticity. For example, a thermoplastic resin. More preferably, it is an engineering plastic having relatively high strength and corrosion resistance. Engineering plastics are exemplified by polycarbonate (PC), polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). More preferably, it is a super engineering plastic having higher strength and corrosion resistance. Super engineering plastics include polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyether ether Examples are ketone (PEEK), thermoplastic polyimide (PI), and polyamideimide (PAI).

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  In this case, the same effect as that of the first embodiment can be obtained.

(Third embodiment)
Next, the configuration of the lithium secondary battery according to the third embodiment of the present invention will be described. 8 and 9 are a top view and a front view showing a schematic configuration of a lithium secondary battery according to the third embodiment of the present invention. A lithium secondary battery 1 a according to the present embodiment includes a battery lid 2 and a battery container 3.

  In the first and second embodiments, a sealing plug which is a kind of degassing valve is not explicitly shown (FIGS. 1 and 2), but in this embodiment, the sealing plug 56 is explicitly shown. The details will be described. The sealing plug of the present embodiment is a valve structure in which the gas vent structure is omitted from the valve structure of the gas vent valve of the first embodiment. As obvious to those skilled in the art, in the case of the first and second embodiments, the sealing plug 56 of this embodiment can be applied separately from the gas vent valve 6. Conversely, also in the present embodiment, the gas vent valve 6 of the first and second embodiments can be applied separately from the sealing plug 56.

  In the present embodiment, the battery lid 2 is a lid for sealing the battery container 3, and is formed of, for example, a steel material such as stainless steel or an aluminum-based material. The battery lid 2 includes a positive electrode terminal 4, a negative electrode terminal 5, insulators 14 and 15, a sealing plug 56, and a safety valve 11.

  The sealing plug 56 is a plug that seals a hole (also referred to as a sealing plug mounting hole (described later)) for injecting the electrolytic solution 7 into the battery container 3 to which the battery lid 2 is welded. By mounting the sealing plug 56 in the sealing plug mounting hole, it is possible to prevent leakage of the electrolyte solution 7 and decomposition gas in the battery container 3. The configuration of the sealing plug 56 will be described later. In the drawing, the sealing plug 56 is provided at one end (corner) of the battery lid 2. However, the present invention is not limited to this example, and may be provided at other end portions (corner portions) or at diagonal positions (example: sealing plug 56 '). .

  Other configurations, for example, the positive electrode terminal 4, the negative electrode terminal 5, the insulators 14 and 15, and the safety valve 11 are the same as those in the first embodiment, and thus description thereof is omitted.

  The battery container 3 is a container for storing a battery main body, and is formed of, for example, a steel material such as stainless steel or an aluminum-based material. The inner surface of the battery container 3 may be in direct contact with the electrolytic solution, but may be covered with an insulating film such as a modified polyolefin.

  The internal configuration of the lithium secondary battery is the same as that of the first and second embodiments (FIG. 3), and thus the description thereof is omitted.

  Next, the configuration of the sealing plug 56 will be described. FIGS. 10-12 is a schematic diagram which shows the structure of the sealing plug which concerns on the 3rd Embodiment of this invention. However, FIG. 10 is a side view (the O-ring 18 and the battery cover 2 are cross sections), FIG. 11 is a perspective view, and FIG. 12 is a cross-sectional view (including the O-ring 18). The sealing plug 56 includes a sealing plug body 61 and a locking structure 62. The sealing plug 56 is fitted into the sealing plug mounting hole 28 provided in the battery lid 2 by a locking structure 62 via a sealing material such as an O-ring 18.

  The sealing plug body 61 has a bulk solid structure having at least one plane (bottom surface). In the example of FIG. 10, it has a cylindrical shape. Then, a locking structure 62 is provided on the one plane so as to extend perpendicularly from the plane. In the example of FIG. 10, the locking structure 62 is formed on the bottom surface of the cylinder so as to extend in the vertical direction from the bottom surface. Further, the O-ring 18 (sealing material) whose bottom surface (plane) is disposed between the sealing plug 56 and the battery cover 2 is pressed against the surface of the battery cover 2 with a predetermined pressing pressure. The stop plug 56 seals the sealing plug mounting hole 28. A center line C <b> 2 in FIG. 10 passes through the centers of the sealing plug body 61 and the locking structure 62.

  The locking structure 62 is provided on the bottom surface of the sealing plug body 61, and extends from the bottom surface in a substantially vertical direction (a downward direction along the center line C2 in FIG. 10). The locking structure 62 is inserted and fitted into the sealing plug mounting hole 28 of the battery lid 2. Thereby, the sealing plug 56 is fixed to the battery lid 2. The center line C2 in FIG. 10 also passes through the centers of the locking structure 62 and the sealing plug mounting hole 28. The locking structure 62 includes a base portion 62a, a plurality of insertion portions 62b, and a protruding portion (return) 62c.

  The base portion 62 a is provided on the bottom surface of the sealing plug body 61 substantially perpendicular to the bottom surface. The base portion 62a has a bulk solid structure. In the case of FIG. 10, it has a cylindrical shape centered on the center line C2. The thickness d5 of the base portion 62a is preferably larger than the height d6 from the bottom surface of the sealing plug body 61 to the contact portion between the O-ring 18 and the locking structure 62 (d5> d6). This is because the sealing performance of the O-ring 18 can be further improved by bringing the O-ring 18 into close contact with the base portion 62a. That is, the O-ring 18 is in close contact with the curved surface above the sealing plug mounting hole 28 of the battery lid 2 and the bottom surface of the sealing plug main body 61, and in addition to the side wall portion of the base portion 62 a, so The performance of sealing the liquid 7 is further improved.

  A plurality of insertion portions 62b are provided on the surface of the base portion 62a so as to surround the center line C2 and its peripheral region 65. And the insertion part 62b is extended in the substantially perpendicular | vertical direction (downward direction along the centerline C2 of FIG. 10) from the base part 62a. Since the end of the insertion part 62b opposite to the base part 62a is not fixed, it can swing. In the case of FIG. 11, the shape obtained by dividing the cylinder into four parts, that is, four insertion parts 62b are provided on the base part 62a. However, the number of insertion parts 62b is not limited to four. The protrusion 62c is provided at the tip of each insertion part 62b, and has a protrusion extending in the direction toward the outside with respect to the center line C2.

  The outer diameter d3 of the circle surrounding the outer sides of the plurality of insertion portions 62b is substantially equal to or more preferably slightly larger than the inner diameter D2 of the sealing plug mounting hole 28. As a result, shake and backlash in a direction parallel to the surface of the battery lid 2 can be suppressed. Further, the outer diameter d4 of the circle surrounding the outer sides of the plurality of protrusions 62c is larger than the inner diameter D2 of the sealing plug mounting hole 28. Thereby, the plurality of protrusions 62 c can be caught on the end of the battery lid 2. As a result, the sealing plug 56 is locked in the sealing plug mounting hole 28, and the sealing plug 56 can be prevented from being detached from the sealing plug mounting hole 28. Further, the length t2 to the base of the protrusion 32c in the locking structure 32 (the length to the base of the protrusion 62c of the insertion portion 62b) is sealed with the sealing plug 56 via the O-ring 18. When fitted in the plug mounting hole 28, the bottom surface of the sealing plug body 61 is moderately pressed against the O-ring 18. As a result, the O-ring 18 can be appropriately sealed.

  The sealing plug main body 61 and the locking structure 62 may be formed of resin (example: plastics). The resin is preferably a resin having high corrosion resistance to the electrolytic solution 7 and its decomposition gas, high strength, and a certain degree of elasticity. For example, a thermoplastic resin. More preferably, it is an engineering plastic having relatively high strength and corrosion resistance. Engineering plastics are exemplified by polycarbonate (PC), polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). More preferably, it is a super engineering plastic having higher strength and corrosion resistance. Super engineering plastics include polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyether ether Examples are ketone (PEEK), thermoplastic polyimide (PI), and polyamideimide (PAI). More preferred is polyphenylene sulfide (PPS).

  The O-ring 18 is made of an elastic member. The elastic member is preferably a material having high corrosion resistance against the electrolyte solution 7 and its decomposition gas and having appropriate elasticity. For example, EPDM (Ethylene Propylene Diene Monomer) is preferable.

  The battery lid 2 is preferably recessed toward the inside of the battery container 3 in the sealing plug mounting hole 28. That is, it is preferable that the battery lid 2 has a flat plate portion 21 and a hollow portion 27 that is connected to the flat plate portion 21 and that is recessed toward the inside of the battery container 3. The reason is as follows. The hollow portion 27 has an inner diameter gradually decreasing (squeezed) from the outside to the inside of the battery container 3. Therefore, when the sealing plug 56 is mounted in the sealing plug mounting hole 28, the insertion portion 62 b and the projection 62 c of the locking structure 62 are inserted into the recess portion 27, so that the recess portion 27 is narrowed. Along the direction along the direction toward the center line C2, it is easily elastically deformed. As a result, the locking structure 62 (outer diameter d4) can be easily entered into the sealing plug mounting hole 28 (inner diameter D2 <d4). When the protrusion 62 c is completely inserted into the sealing plug mounting hole 28 at the tip of the recess 27, the protrusion 62 c is released from the restriction of the recess 27. Thereby, the elastic deformation of the insertion portion 62b is released, and the state returns to the original state (shape). At that time, the protruding portion 62 c enters the sealing plug mounting hole 28 and is caught by the inner peripheral portion of the sealing plug mounting hole 28. This state is shown in FIG. The shape like the depression 27 can be produced by, for example, press working.

  Furthermore, after the sealing plug 56 is attached, the sealing plug 56 is attached to the sealing plug attachment hole 28 only by being caught at the inner peripheral portion of the sealing plug attachment hole 28 by the protrusion 62c. Become. At this time, when the gas pressure in the battery container 3 rises, the recess 27 is strongly pressed against the insertion portion 62b due to the effect of elastic deformation on the curved surface. Thereby, the sealing plug 56 can be made more difficult to come off with respect to an increase in the gas pressure in the battery container 3.

  As shown in FIG. 10, the angle γ formed by the lower surface of the protrusion 62c and the surface parallel to the center line C2 of the insertion portion 62b is preferably smaller than 90 degrees. More preferably, it is in the range of 30 to 60 degrees. This is because the resistance when the protrusion 62c slides on the recess 27 is reduced. Further, the angle δ formed by the end of the battery lid 2 on the sealing plug mounting hole 28 side and the upper surface of the protrusion 62c is preferably in the range of 30 to 60 degrees. More preferably, it is 40 to 50 degrees. This is because the protrusion 32c is appropriately fixed at the end of the battery lid 2 so that the sealing plug 56 does not come off against the internal pressure of the battery case 3. However, there is a possibility that the sealing plug 56 may be detached with a certain amount of force simply by being fitted. However, there is no problem if the shape of the projection 62c is designed so that a certain amount of force necessary for the removal is equal to or greater than the pressure at which the safety valve 11 bursts. Moreover, you may adhere | attach with an adhesive agent as needed.

  When the sealing plug 56 is inserted into the sealing plug mounting hole 28, the sealing plug 56 is inserted together with the sealing material exemplified by the O-ring 18. The O-ring (sealing material) 18 is elastically deformed by being sandwiched between the upper surface of the recess 27 and the bottom surface of the sealing plug body 61. Thereby, the electrolytic solution 7 and the decomposition gas inside the battery container 3 are isolated from the outside with the flat plate portion 21, the recessed portion 27, the O-ring 18, and the sealing plug body 61 (bottom surface) of the battery lid 2 as boundaries. I can do it. As a result, even if there is a gap through which gas can flow between the insertion portion 62b (protrusion portion 62c) of the sealing plug 56 and the sealing plug mounting hole 28 of the battery lid 2, gas leakage can be prevented. And the electrolyte solution 7 and decomposition gas inside the battery container 3 do not leak outside.

  About the manufacturing method of the sealing plug 56, it can form using the existing manufacturing method like the injection molding method using a predetermined resin material, for example.

  The recess 27 of the battery lid 2 is a curved surface having a predetermined curvature R (convex upward) in a cross-sectional view as shown in FIG. However, the present invention is not limited to this example. For example, a conical side surface shape having a downward surface (tapered surface) at a predetermined angle (example: about 45 degrees) with respect to the flat plate portion 21 may be used. Further, the end of the conical side surface shape having a surface facing downward at a predetermined angle may further have a curved surface shape having a predetermined curvature R ′.

  When the sealing plug 56 is inserted into the sealing plug mounting hole 28, the O-ring 18 may be coated with a material that enhances sealing properties such as grease. Further, without using a sealing material such as the O-ring 18, for example, the sealing plug 56 may be inserted together with a sealing resin or adhesive and then cured.

  Further, the sealing plug 56 may be a metal. This is because the possibility of generating chips is very small because it does not have a screw structure. In that case, the metal is preferably the same metal as the battery lid 2. This is because if different metals are used, corrosion tends to occur. In addition, as a manufacturing method, for example, an existing manufacturing method such as a method of manufacturing using a mold or a method of cutting and manufacturing from a bulk metal can be used.

  Next, a method for manufacturing a lithium secondary battery according to the third embodiment of the present invention will be described.

  First, referring to FIG. 8, FIG. 9, and FIG. 3, first, the battery lid 2 (positive electrode terminal) is inserted into the battery container 3 (however, including the positive electrode 8 and the negative electrode 9 and the electrolyte solution 7 has not yet been injected). 4, the negative electrode terminal 5, the insulators 14 and 15, and the safety valve 11, and the sealing plug 56 is not yet mounted). Thereby, the secondary battery before injecting the electrolyte solution 7 is prepared (step S01).

  Next, a predetermined amount of the electrolyte 7 is injected into the battery container 3 from the sealing plug mounting hole 28 (step S02). Subsequently, it is left at room temperature for a while until the electrolyte solution 7 in the battery container 3 is stabilized (step S03). Thereafter, the generated decomposition gas is extracted from the battery container 3 and replaced with an inert gas (step S04). Next, the secondary battery is temporarily charged (supplementary charge) by a predetermined amount (step S05). Subsequently, it is left for a while at room temperature until the electrolyte solution 7 in the battery container 3 is stabilized again (step S06). Thereafter, the generated decomposition gas is extracted from the battery container 3 and replaced with an inert gas (step S07).

  Thereafter, the O-ring 18 is attached to the prepared sealing plug 56. Then, the sealing plug 56 (FIGS. 10 to 12) is inserted and mounted in the sealing plug mounting hole 28 of the secondary battery for which the processing of steps S02 to S07 has been completed (step S08). Thereby, sealing of the secondary battery (encapsulation of the electrolytic solution 7) is completed, and the secondary battery 1a can be manufactured.

  At this time, since the mounting is simply performed by inserting and pressing, the work is easy, no extra man-hours are required, and labor and time can be greatly reduced. In addition, since it does not have a screw structure, there is no possibility of metal chips being generated, and battery performance can be deteriorated and safety can be maintained. It is possible to avoid adversely affecting sex.

  The present invention is not limited to the embodiments described above, and it is obvious that the embodiments can be appropriately modified or changed within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1, 1a Lithium secondary battery 2 Battery cover 3 Battery container 4 Positive electrode terminal 5 Negative electrode terminal 6, 6A Gas vent valve 7 Electrolytic solution 8 Positive electrode 9 Negative electrode 11 Safety valve 14, 15 Insulator 16, 18 O-ring 21 Flat plate part 22 Recessed part 22A female screw structure 23 gas vent valve mounting hole 27 recess 28 sealing plug mounting hole 31 gas vent main body 31a upper gas vent valve main body 31b lower gas vent valve main body 32 locking structure 32A screw structure 32a base portion 32b insertion portion 32c protrusion Part 33 Second hole 34, 34A Elastic member 34a Bottom part 34b Side face part 34c Upper end part 35 First hole 56 Sealing plug 61 Sealing plug body 62 Locking structure 62a Base part 62b Insertion part 62c Projection part 65 Peripheral region

Claims (4)

The body,
A locking structure that extends in a substantially vertical direction with respect to the bottom surface of the main body and can be inserted into a hole to be attached;
The locking structure is
A plurality of insertion portions extending in the substantially vertical direction from the periphery of the bottom surface;
A valve structure comprising: a protrusion provided at a tip portion of each of the plurality of insertion portions and facing outward from the substantially vertical direction. The valve structure is provided on a bottom surface of the main body and disposed between the plurality of insertion portions, and a first hole provided on another surface of the main body different from the bottom surface. Two holes, an internal space that is provided inside the main body and connects the first hole and the second hole, and an elastic member that is disposed in the internal space and seals the first hole Have
The elastic member is deformed so that the gas is released from the first hole to the second hole when the gas having a predetermined pressure or more comes into contact with the first hole. The valve structure according to claim 1, wherein A battery body comprising a battery container and a battery lid provided on the battery container;
The valve structure according to claim 1 or 2, wherein the valve structure is attached to an attachment hole of the battery lid via an O-ring.
The battery structure is characterized in that the plurality of insertion portions are inserted into the mounting holes, and are locked to the mounting holes by the protrusions.   The battery according to claim 3, wherein the mounting hole is recessed toward the inside of the battery container.

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