Valve plug

Abstract

A valve plug (1; 100; 1000; 2000) for venting gases generated inside a container comprises a sealing member (10; 110; 1010; 2010) and a vent plunger (12; 112; 1012; 2012) cooperating with the sealing member. The vent plunger (12; 112; 1012; 2012) comprises at least one vent passage (20; 120; 1020; 2020) and is axially movable within the sealing member (10; 110; 1010; 2010) between a closure position, in which the sealing member seals the vent passage (20; 120; 1020; 2020), and an opening position, in which the vent passage (20; 120; 1020) is not sealed by the sealing member so as to allow fluids to pass through said vent passage.

Description

"VALVE PLUG"DESCRIPTIONField of the invention

[0001] The present invention relates to a valve plug suitable for being installed in a bore, for example a venting or a filling bore, of a cover of a container for venting the gases generated inside the container . In particular, but not exclusively, the valve plug is suitable for being installed on an energy container, such as a battery cell, a capacitor, or a supercapacitor, for venting the gas generated inside the container, for example by the battery formation process , moisture, or the gases generated while filling the container, for example by the chemical reaction between an electrolyte and an active material .Background of the invention

[0002] As it is known, in the formation process of batteries , such as lithium-ion batteries , or, in general, in the formation, production, manufacturing of energy containers , gas may be generated inside the container . These gases have to be discharged from the interior of the container . I f the gas generated in the formation process cannot be discharged successfully, gas expansion will occur and may seriously affect the properties and operation of the energy container .

[0003] Venting devices for discharging the gases have already been proposed . However, these devices do not guarantee a perfect airtight when they are in the close position and the pressure inside the battery raises beyond a certain threshold . In addition, some known venting devices have a complex structure and are difficult to assemble and disassemble .

[0004] Other known plug devices are designed to only temporary seal the battery, then they are unplugged and disposed . Therefore, there is the problem that every battery cell generates waste that must be properly handled .

[0005] Therefore, there is the need of solving the problem of discharging the gases generated inside a battery cell during the battery formation process , overcoming at the same time the limits and drawbacks of the known venting devices .

[0006] Another object of the invention is to provide a valve plug that can be used not only for discharging gas , but also for injecting a fluid, for example an electrolyte liquid, inside the battery .

[0007] These objects are achieved with a valve plug according to claim 1 , with a vent assembly according to claim 10 , with a method for venting gases according to claim 15 , and with a method for injecting a liquidaccording to claim 16 . The dependent claims describe preferred embodiments of the invention .Brief description of the drawings

[0008] features and advantages of the valve plug, vent assembly and methods according to the invention will be apparent from the description given below of preferred embodiments thereof , made by way of a non-limiting examples with reference to the appended drawings , wherein :

[0009] - Figure 1 is an axial section of a valve plug according to one embodiment of the invention, in a closed position;

[0010] - Figure 2 is the axial section of the valve plug of Figure 1 , in an open position;

[0011] - Figure 3 is an axial section of the vent plunger of the valve plug of figures 1 and 2 ;

[0012] - Figure 4 is a perspective view of the vent plunger of figure 3 ;

[0013] - Figure 5 is an axial section of the sealing member of the valve plug of figures 1 and 2 ;

[0014] - Figures 6 and 7 are axial sections of a valve plug according to another embodiment of the invention, in a closed and open position, respectively;

[0015] - Figures 8 and 9 are axial sections of a valve plug according to another embodiment of the invention, ina closed and open position, respectively;

[0016] - Figure 10 is an axial section of a vent assembly according to one embodiment of the invention;

[0017] - Figure 11 is an axial section of a vent assembly according to another embodiment of the invention; and

[0018] - Figure 12 is an axial section of a vent assembly according to further embodiment of the invention .Detailed description of the invention

[0019] In the following description, all directional references (e . g . , top, bottom, up, down, left , right , vertical, horizontal, clockwise, and counterclockwise ) are used only for identification purposes to assist the reader in understanding the described embodiments of the invention and are not intended to create limitations , particularly with respect to the location, orientation, or use of the described embodiments .

[0020] Conjunction references (e . g . , fixed, coupled, connected, and the like ) are to be interpreted broadly and may include intermediate elements between a connection of elements and a relative movement between elements . Thus , conjunction references do not neces sarily imply that two elements are directly connected and in a fixed relationship to each other .

[0021] In addition, same or similar elements belonging to different embodiments of the invention are denoted with the same reference numbers.

[0022] In the drawings, reference numbers 1; 100; 1000; 2000 globally denote a valve plug suitable for being installed in a bore 2, for example a venting or a filling bore, of a cover 3 of a container for venting the gases generated inside the container.

[0023] The valve plug is specifically intended to be installed on a battery cell, for example a lithium-ion battery cell, for venting the gas generated within the battery cell by the battery formation process and, in a preferred embodiment, for introducing an electrolyte liquid in the battery cell.

[0024] The valve plug 1; 100; 1000; 2000 comprises a sealing member 10; 110; 1010; 2010 and a vent plunger 12; 112; 1012; 2012 cooperating with the sealing member 10; 110; 1010; 2010.

[0025] A plunger seat 14; 114; 1014; 2014 axially extends in the sealing member 10; 110; 1010; 2010. The plunger seat at least partially accommodated the vent plunger.

[0026] In one embodiment, the sealing member 10; 110; 1010; 2010 has an axial-symmetric shape and extends around a main sealing member axis X.

[0027] In one embodiment, the vent plunger 12; 112; 1012;2012 also has an axial-symmetric shape and extends around a main vent plunger axis Y.

[0028] In one embodiment, when the vent plunger 12; 112; 1012; 2012 is at least partially inserted into the sealing member 10; 110; 1010; 2010, the vent plunger is coaxial to the sealing member.

[0029] The sealing member 10; 110; 1010; 2010 comprises a head portion 16; 116; 1016; 2016 and a bore engagement portion 18; 118; 1018; 2018.

[0030] The bore engagement portion 18; 118; 1018; 2018 extends from the head portion 16; 116; 1016; 2016.

[0031] The bore engagement portion 18; 118; 1018; 2018 is adapted to be inserted into the bore 2.

[0032] The bore engagement portion 18; 118; 1018; 2018, when engages, that is, penetrates, the bore 2, makes a seal with an edge 2' of the bore 2.

[0033] In the examples shown in the drawings, the bore engagement portion 18; 118; 1018; 2018 passes completely through the bore 2 to protrude inside the container with its distal end 18' ; 118' ; 1018' ; 2018' . In this case, the distal end 18' ; 118' ; 1018' ; 2018' seals the inner side of the edge 2' of the bore 2, that is, the side facing the interior of the container. For example, the distal end 18' ; 118' ; 1018' ; 2018' of the bore engagement portion forms, in its outer surface, and undercut 18",118"; 1018" engaging the inner side of the edge 2' of the bore 2.

[0034] The vent plunger 12; 112; 1012; 2012 is at least partially arranged in the plunger seat 14; 114; 1014; 2014. In the vent plunger at least one vent passage 20; 120; 1020; 2020 is made. The vent passage 20; 120; 1020; 2020 is suitable for providing a fluidic communication path between the interior of the container and the exterior of the container.

[0035] The vent plunger 12; 112; 1012; 2012 is axially movable with respect to the sealing member 10; 110; 1010; 2010.

[0036] The vent plunger 12; 112; 1012; 2012 can move between a closure position, in which the sealing member 10; 110; 1010; 2010 seals the vent passage 20; 120; 1020 so as to prevent fluids from passing through said vent passage, and an opening position, in which the vent passage 20; 120; 1020; 2020 is not sealed by the sealing member so as to allow fluids to pass through said vent passage .

[0037] In embodiments shown in figures 1-7, the closure position corresponds to a retracted position of the vent plunger 12; 112 with respect to the sealing member, while the open position corresponds to an advanced position of the vent plunger 12; 112 with respect to the sealingmember .

[0038] In the embodiments of figures 8 , 9, on the contrary, the closure position corresponds to an advanced position of the vent plunger 2012 with respect to the sealing member, while the open position corresponds to a retracted position of the vent plunger 2012 with respect to the sealing member .

[0039] In one embodiment shown in figure 10 , the bore engagement portion 1018 comprises a diaphragm portion 1018a that axially closes the plunger seat 1014 . The vent plunger 1012 comprises a needle end portion 1012 ' . The vent passage 1020 terminates in the needle end portion 1012 ' . When the vent plunger 1012 is in the retracted closure position, the needle end portion 1012 ' is spaced apart from the diaphragm portion 1018a, so that the plunger seat 1014 , and therefore the vent passage 1020 , is sealed by the diaphragm portion 1018a . When the vent plunger 1012 is in the advanced opening position, the needle end portion 1012 ' pierces the diaphragm portion 1018a and passes through it to project in the interior of the container .

[0040] In embodiments shown in figures 1-7 , the vent plunger 12 ; 112 ends with a closed distal plug portion 12a; 112a . In the retracted closure position, this distal plug portion 12a; 112a sealingly engages the boreengagement portion 18; 118. In the advanced opening position, the distal plug portion 12a; 112a disengages from the bore engagement portion 18; 118.

[0041] For example, the closed distal plug portion 12a; 112a has a conical end that facilitates the insertion of the vent plunger 12; 112 in the sealing member 10; 110. In an outer surface of the closed distal portion 12a; 112a, just above the conical end, an engagement rim 12a' ; 112a' is provided, which is suitable for being engaged by the distal end 18' ; 118' of the bore engagement portion 18; 118 when the vent plunger 12; 112 is in the retracted position .

[0042] In one embodiment, at least the head portion 16; 116; 1016 of the sealing member 10; 110 is made of an elastically deformable material, for example rubber EPDM. The axial displacement of the vent plunger 12; 112 uses the elastic deformability of the head portion 16; 116; 1016.

[0043] In one embodiment, the vent plunger 12; 112; 1012; 2012 is made in a material having a higher stiffness than the material of the sealing member 10; 110; 1010; 2010, so that, when a force is applied to the vent plunger to move the vent plunger from the closure position to the opening position, the vent plunger deforms the sealing member and such a deformation allows the displacement ofthe vent plunger.

[0044] In one embodiment, the sealing member 10; 110; 1010; 2010 is integrally made in a single piece. In one embodiment, also the vent plunger 12; 112; 1012; 2012 is integrally made in a single piece.

[0045] In one embodiment, the vent plunger 12; 112; 1012 comprises a vent plunger proximal portion 12b; 112b; 1012b; 2012b that, at least in the closure position, sealingly engages the head portion 16; 116; 1016; 2016 of the sealing member so as to prevent external agents from entering into the vent passage 20; 120; 1020; 2020.

[0046] In one embodiment, the head potion 16; 116; 1016; 2016 of the sealing member has a top surface 16a; 116a; 1016a; 2016a and the proximal portion 12b; 112b; 1012b of the vent plunger lies on this top surface.

[0047] It can be noted that, in one embodiment, a distance B from a sealing rim 19a; 119a; 2019a of the vent plunger to a distal sealing cone of the vent plunger 19b; 119b; 2019b is the same or less than a distance A from the top surface of the head portion 16; 116; 2016 of the sealing member 10; 110; 2010 and and the end of the bore engagement portion 18; 118; 2018. Thanks to this arrangement, a kind of pretension, improving the sealing effect, is achieved in the plug device when it is in the closed sealing position.

[0048] In one embodiment, the plunger seat 14 ; 114 ; 2014 comprises a plunger seat proximal section 14a ; 114a; 2014a, mainly made in the head portion 16 ; 116 ; 2016, and a plunger seat distal section 14b; 114b; 2014b, mainly extending in the engagement portion 18 ; 118 ; 2018 . The plunger seat proximal section 14a; 114a; 2014a has a proximal section diameter dl and the plunger seat distal section 14b; 114b; 2014b has a distal section diameter d2 . The proximal section diameter dl is greater than the distal section diameter d2 .

[0049] In one embodiment , the plunger seat proximal section 14a; 114a; 2014a and the plunger seat distal section 14b; 114b; 2014b are linked by a plunger seat conical intermediate section 14c; 114 c; 2014c .

[0050] Correspondingly, the vent plunger 12 ; 112 , 2012 comprises , between the proximal portion 12b; 112b; 2012b, which rests on the top surface of the head portion of the sealing member, and the distal plug portion 12a; 112a; 2012a, a vent plunger first intermediate portion 12c; 112c; 2012c which extends from the proximal portion 12b ; 112b; 2012b and a vent plunger second intermediate portion 12d; 112d; 2012d, which extends from the first intermediate portion 12c; 112c; 2102c and terminates with the distal plug portion 12a; 112a; 2012a .

[0051] The vent plunger first intermediate portion 12c ;112c; 2012c is inserted, with shape coupling, in the plunger seat proximal section 14a; 114a; 2104a; the vent plunger second intermediate portion 12d; 112d; 2012d is inserted, with shape coupling, in the plunger seat distal section 14b; 114b; 2014b .

[0052] In one embodiment , the first intermediate portion 12c; 112c; 2012c and the second intermediate portion 12d; 112d; 2012d are connected by a vent plunger intermediate conical portion 12e ; 112e ; 2012e, which has the same conicity of the plunger seat conical intermediate section 14 ; 114c; 2014c .

[0053] In one embodiment , the vent plunger first intermediate portion 12c; 112c has an axial extension which is shorter than the axial extension of the plunger seat proximal portion 14a, 114a, so that , when the vent plunger is in the retracted closure position, the vent plunger intermediate conical portion 12e, 112e is spaced apart from the plunger seat conical intermediate section 14 , 114c and the vent plunger second intermediate portion 12d; 112d partially extends in the plunger seat proximal section 14a; 114a (Figure 1 ) ; when the vent plunger 12 , 112 is pressed downwards and the sealing member proximal head 16 ; 116 is deformed, that is , is axially pressed (at least in a portion surrounding the plunger seat 20 , 120 ) , the vent plunger first intermediate portion 12c; 112cfurther penetrates in the plunger seat proximal section14a; 114a until the vent plunger intermediate conical portion 12e ; 112e abuts against the plunger seat conical intermediate section 14 ; 114c . In this axial position of the vent plunger, the second intermediate portion 12d; 112d completely extends in the plunger seat distal section 14b; 114b (Figure 2 ) .

[0054] In one embodiment (Figures 1-5 ) , the vent passage 20 is axially formed in the vent plunger 12 . In other words , the vent plunger 12 is axially hollow, except for the distal plug portion 12a, which closes the vent passage 20 .

[0055] In a rearward position from the distal plug portion 12a, at least one radial opening 20 ' communicating with the vent passage 20 is formed in the vent plunger 12 . Preferably, two or more radial openings 20 ' , evenly distributed along the circumference, are obtained in the lateral wall of the vent plunger 12 . This at least one radial opening 20 ' is located axially beyond the bore engagement portion 18 of the sealing member 10 in the forward direction, when the vent plunger 12 is in the advanced opening position (Figure 2 ) .

[0056] In another embodiment shown in Figures 6 and 7 , the vent passage 120 is formed by a vent passage proximal portion 120a, obtained within the vent plunger 112 , and avent passage distal portion 120b, obtained between the outer surface of the vent plunger 112 and an inner wall of the plunger seat 114 .

[0057] In the vent plunger 112 at least one side opening 120d is formed to connect the vent passage proximal portion 120a with the vent passage distal portion 120b .

[0058] For example, the vent passage proximal portion 120a is axially obtained in the vent plunger proximal portion 112b and in the vent plunger first intermediate portion 120c . The at least one side opening 120d may be formed in the vent plunger intermediate conical portion 112e . The vent passage distal portion 120b may be formed by one or more longitudinal channels obtained in the lateral wall of the vent plunger second intermediate portion 112d .

[0059] In another embodiment (Figures 8 , 9 ) , the vent passage 2020 is axially formed in the vent plunger 2012 , except for the vent plunger proximal portion 2012b, which is closed . The vent passage 2020 is distally open towards the inside of the container and terminates, at the proximal end, with radial passages 2020a . The radial passages 2020a cross the vent plunger first intermediate portion 2012c . When the vent plunger 2012 is in the advanced closing position, the radial passages 2020a are sealed by the inner wall of the plunger seat proximal section 2014a and / or by the interaction between theannular rim 2019a and the top surface of the head portion2016a of the sealing member 2016 (figure 8) . When the vent plunger 2012 is pulled upwards in the retracted opening position, the annular rim 2019a disengages from the top surface of the head portion 2016 of the sealing member 2016 and the radial passages 2020a open towards the outside of the container (Figure 9) .

[0060] As shown in Figures 10 and 11, the vent plunger 12; 112; 1012; 2012 is adapted to fluidically connect the interior of the container with a suction device 200; 200' for the suction of gases, when the suction device 200; 200' is coupled to the vent plunger 12; 112; 1012; 2012 in the opening position.

[0061] Another object of the present invention is therefore a vent assembly 500; 500' for venting gases generated within a container. The vent assembly 500; 500' comprises a valve plug 1; 100; 1000; 2000 as disclosed above and a suction device 200; 200' cooperating with the valve plug for suctioning the gases from the container through the vent passage 20; 120; 1020; 2020.

[0062] The suction device comprises a device distal portion 210; 210' configured to axially engage the vent plunger 12; 112; 1012; 2012 and operable to cause the vent plunger to move from the closed position to the opening position, and vice versa.

[0063] The device distal portion 210; 210' may be provided on an adapter 510; 510' suitable for coupling the vent plug 1; 100; 1000; 2000 according to the invention with a suction device already commercially available.

[0064] In the following, the term "suction device 200; 200'" will also include a suction device provided with the adapter 510; 510' .

[0065] It should be noted that, in one embodiment, the suction device 200; 200' is suitable for allowing the vent plunger to return from the opening position to the closure position thanks to reverse force generated by the elastic deformation of the sealing member 10; 110; 1010; 2010.

[0066] It should be further noted that the suction device 200; 200' may be used not only to suction gases from the container, but also be to inject a liquid, for example an electrolyte liquid, in the container through the vent passage, when the vent plunger is in the open position.

[0067] In one embodiment, the device distal portion 210; 210' is provided with sealing means 220; 220' suitable for sealingly coupling the device distal portion 210; 210' and the vent passage 20; 120; 1020; 2020. For example, the device distal portion 210' is provided with a sealing ring 222' suitable for sealingly engaging a proximal end 12b; 112b; 1012b of the vent plunger, aroundthe vent passage 20; 120; 1020.

[0068] In an alternative embodiment, the sealing means 200; 220 ' may be provided on the vent plunger proximal portion 12b; 112b; 1012b or on both the device distal portion 210; 210' and the valve plug 1; 100; 1000.

[0069] For example, in the embodiment of Figure 11, the head portion 16; 116; 1016; 2016 of the sealing member 10; 110; 1010; 2010 forms, around the vent plunger 12; 112; 1012; 1012, an annular sealing protrusion 222. The device distal portion 210; 210' forms an annular surface 224 suitable for sealingly engaging such an annular sealing protrusion 222 when the device distal portion 210 axially engages the vent plunger 12; 112; 1012; 2012.

[0070] In order to vent gases generated within a container, for example a lithium-ion battery, the above described vent assembly 500; 500' is provided. The valve plug 1; 100; 1000; 2000 is coupled to the bore 2 of the cover 3 of the container. The device distal portion 210; 210' of the vent assembly is then brought into contact with the valve plug 1; 100; 1000; 2000.

[0071] The device distal portion 210; 210' is actuated so as to press the vent plunger 12; 112; 1012 in the advanced opening position or to pull the vent plunger 2012 in the retracted opening position.

[0072] The gases can then be sucked by the suction device200; 200' through the vent passage 20; 120; 1020; 2020.

[0073] In order to introduce a fluid into a container, for example an electrolyte liquid in a battery cell, the above described vent assembly 500; 500' is provided. The valve plug 1; 100; 1000; 2000 is coupled to the bore 2 of the cover 3 of the container. The device distal portion 210; 210' of the vent assembly is then brought into contact with the valve plug 1; 100; 1000; 2000.

[0074] The device distal portion 210; 210' is actuated so as to press the vent plunger 12; 112; 1012 in the advanced opening position or to pull the vent plunger 2012 in the retracted opening position.

[0075] The liquid can then be injected into the container through the vent passage 20; 120; 1020; 2020.

[0076] In one embodiment, the device distal portion 210; 210' contacts the head portion of the sealing member or the vent plunger by means of the sealing means 220; 220' .

[0077] The sealing means are pressed so as to sealingly coupling the device distal portion 210; 210' and the vent passage 20; 120; 1020; 2020.

[0078] In one embodiment, when the device distal portion 201; 210' is actuated, the head portion 16; 116; 1016 or the end portion 2018' of the sealing member is elastically deformed in order to allow the relative movement of the vent plunger with respect to the sealingmember from the closure position to the opening position .

[0079] The elastic deformation of the sealing member may result in a reverse force that causes the vent plunger to return from the opening position to the closure position .

[0080] For example, the valve plug and vent assembly according to the invention can be used in the following process of formation of a battery cell .

[0081] The valve plug is coupled to the venting or filling bore of the battery cell container . The battery cell is initially partially filled with the electrolyte liquid ( for example up to 75% of the battery capacity) .

[0082] The battery cell, including the valve plug, can then be subjected to other processes .

[0083] After a predetermined time interval, a degassing process can be activated by means of the vent assembly to vent the gases generated inside the battery cell during the battery formation process .

[0084] The battery cell, including the same valve plug, can then be subjected to other proces ses .

[0085] Having evacuated the gases , the cell battery can be completely filled with the electrolyte liquid ( for example up to 100% of the battery capacity) .

[0086] In some embodiments , the process may provide filling the battery cell to 100% by applying an overpressure, for example with nitrogen .

[0087] It should be noted that , when the valve plug is in the closure position, no air flow or pressure can escape through the valve plug . In some embodiments , the sealing is achieved by the interaction between the plug distal portion and the sealing member engagement portion .

[0088] When the valve plug is in the open position, gases can be sucked in a controlled atmosphere and cannot escape in the environment . In some embodiments , this is achieved thanks to the sealed coupling between the suction device and the vent plug and thanks to the sealing contacts between outer surfaces of the vent plunger and the sealing member, in particular between the vent plunger proximal portion and the sealing member proximal head .

[0089] The same sealing effect ensures that the liquid is injected in the container in controlled atmosphere .

[0090] However, in certain cases it could be desirable to allow the gases to flow from the container to the external environment through the vent plug when the top surface of the proximal portion is sealed, for example by the f illing / suction device . Therefore, in one embodiment shown for example in figures 1-4 , a radial groove communicating with the vent passage is made in the top surface of the proximal portion of the vent plug .

[0091] It should be noted that the same valve plug can beused during all the filling and degas sing processes .

[0092] The valve plug can be made to ensure chemical compatibility with electrolyte gases .

[0093] The valve plug is easy to clean, to assemble and disassemble .

[0094] A person skilled in the art may make modifications and adaptations to the embodiments of the valve plug according to the invention, replacing elements with others functionally equivalent so as to satisfy contingent requirements while remaining within the scope of protection of the following claims .

[0095] Each of the characteristics described as belonging to a possible embodiment may be realized independently of the other embodiments described .

Claims

CLAIMS1. Valve plug (1; 100; 1000; 2000) suitable for being installed in a bore (2) of a cover (3) of a container for venting gases generated inside the container, the valve plug comprising a sealing member (10; 110; 1010; 2010) and a vent plunger (12; 112; 1012; 2012) cooperating with the sealing member, wherein:- a plunger seat (14; 114; 1014; 2014) axially extends in the sealing member (10; 110; 1010) ;- the sealing member (10; 110; 1010) comprises a head portion (16; 116; 1016; 2016) and a bore engagement portion (18; 118; 1018; 2018) , wherein the bore engagement portion (18; 118; 1018; 2018) extends from the head portion (16; 116; 1016; 2016) and is adapted to be inserted into the bore (2) so as to make a seal with the edge (2' ) of the bore (2) ;- the vent plunger (12; 112; 1012; 2012) comprises at least one vent passage (20; 120; 1020; 2020) and is at least partially arranged in the plunger seat (14; 114; 1014; 2014) such that,- the vent plunger (12; 112; 1012; 2012) is axially movable with respect to the sealing member (10; 110;1010; 2010) , wherein the movement is between- a closure position, in which the sealing member sealsthe vent passage (20; 120; 1020; 2020) so as to prevent fluids from passing through said vent passage,- and an opening position, in which the vent passage (20; 120; 1020) is not sealed by the sealing member so as to allow fluids to pass through said vent passage.

2. Valve plug according to claim 1, wherein the bore engagement portion (1018) comprises a diaphragm portion (1018a) that axially closes the plunger seat (1014) , and wherein the vent plunger (1012) comprises a needle end portion (1012' ) which, when the vent plunger is in the retracted closure position, is spaced from the diaphragm portion (1018a) , and which, when the vent plunger is in the advanced opening position, passes through the diaphragm portion (1018a) .

3. Valve plug according to claim 1 or 2, wherein the vent plunger (12; 112) ends with a closed distal plug portion (12a; 112a) , wherein, in the closure position, said distal plug portion (12a; 112a) sealingly engages the bore engagement portion (18; 118) , and wherein, in the opening position, said distal plug portion (12a; 112a) disengages from the bore engagement portion (18; 118) . . Valve plug according to any one of the preceding claims, wherein at least a head portion (16; 116; 1016) and / or a distal end portion (2018' ) of the sealing memberis made of an elastically deformable material and wherein the axial displacement of the vent plunger uses the elastic deformability of the head portion and / or distal end portion of the sealing member.

5. Valve plug according to any one of the preceding claims, wherein the vent plunger (12; 112; 1012; 2012) comprises a proximal portion (12b; 112b; 1012b; 2012b) that sealingly engages the head portion (16; 116; 1016; 2016) of the sealing member so as to prevent external agents from entering into the vent passage.

6. Valve plug according to any one of claims 3-5, wherein the vent passage (20) is axially formed in the vent plunger (12) and wherein, in a rearward position from the distal plug portion (12a) , at least one radial opening (20' ) communicating with the vent passage (20) is formed in the vent plunger (12) , said at least one radial opening (20' ) being located axially beyond the bore engagement portion (18) in the forward direction when the vent plunger (12) is in the advanced opening position.

7. Valve plug according to any one of claims 3-5, wherein the vent passage (120) is defined by a vent passage proximal portion (120a) formed within the vent plunger (112) and a vent passage distal portion (120b) formed between the outer surface of the vent plunger (112) and an inner wall of the plunger seat (114) , in thevent plunger (112) at least one side opening (120d) being formed to connect the vent passage proximal portion (120a) with the vent passage distal portion (120b) .

8. Valve plug according to any one of the preceding claims, wherein a distance (B) from a sealing rim (19a; 119a; 2019a) of the vent plunger to a distal sealing cone of the vent plunger (19b; 119b; 2019b) is the same or less than a distance (A) from the top surface of the head portion (16; 116; 2016) of the sealing member (10; 110; 2010) and the end of the bore engagement portion (18; 118; 2018) .

9. Valve plug according to any one of the preceding claims, wherein the vent plunger with at least one vent passage (20; 120; 1020; 2020) is adapted to fluidically connect the interior of the container with a suction device (200; 200' ) for the suction of gases when said suction device is coupled to the vent plunger in the opening position.

10. A vent assembly (500; 500' ) for venting gases generated within a container, comprising a valve plug (1; 100; 1000; 2000) according to any one of the preceding claims and a suction device (200; 200' ) cooperating with the valve plug for suctioning the gases from the container through the vent passage (20; 120; 1020; 2020) , wherein the suction device comprises a device distalportion (210; 210' ) configured to axially engage the vent plunger (12; 120; 1020; 2020) and operable to cause the vent plunger to move from the closure position to the opening position, and vice versa.

11. Vent assembly according to claim 10, wherein said device distal portion (210; 210' ) and / or the valve plug (1; 100; 1000; 2000) is provided with sealing means (220; 220' ) suitable for sealingly coupling the device distal portion (210; 210' ) and the vent passage (20; 120; 1020; 2020) .

12. Vent assembly according to claim 10, wherein the head portion (16; 116; 1016; 2016) of the sealing member (10; 110; 1010) forms, around the vent plunger, an annular sealing protrusion (222) , and wherein the device distal portion forms an annular surface (224) suitable for engaging said annular sealing protrusion (222) when the device distal portion (210) axially engages the vent plunger (12; 112; 1012; 2012) .

13. Vent assembly according to claim 10, wherein the device distal portion (210' ) is provided with a sealing ring (222' ) suitable for sealingly engaging a proximal end (12b; 112b; 1012b) of the vent plunger, around the vent passage (20; 120; 1020) .

14. Battery cell, comprising a cover in which a vent or filling bore is made and a valve plug according to anyoneof the claims 1-9 installed in the vent or filling bore .15 . Method for venting gases generated within a container by means of the vent assembly according to any one of claims 10-13 , comprising the steps of : a) bringing the device distal portion of the vent assembly into contact with the valve plug; b) actuating the device distal portion so as to pres s or pull the vent plunger in the opening position; c) suctioning gases through the vent passage .16 . Method for introducing a fluid into a container battery by means of the vent assembly according to any one of claims 10-13 , comprising the steps of :(a) bringing the device distal portion of the vent assembly into contact with the valve plug; b) actuating the device distal portion so as to pres s or pull the vent plunger in the opening position; c) introducing the fluid into the container through the vent passage .17 . Method according to claim 15 or 16, wherein, in step a) , the device distal portion contacts the head portion of the sealing member or the vent plunger by means of the sealing means , and wherein, in step b) , the sealing means are pressed so as to sealingly coupling the device distal portion and the vent passage .18 . Method according to claim 15 or 16 or 17 , wherein,in step b) , the head portion and / or the distal end portion of the sealing member is elastically deformed in order to allow the relative movement of the vent plunger with respect to the sealing member from the closure position to the opening position .19 . Method according to claim 18 , wherein the elastic deformation results in a reverse force in order to return the vent plunger with respect to the sealing member from the opening position to the closure position . 20 . Method according to any of the claims 15-19, wherein the container is a battery cell and wherein the gases are generated during the battery formation process .21 . Method according to any of the claims 16-20 , wherein the container is a battery cell and wherein the fluid is an electrolyte liquid .

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