Degassing device for a rechargeable electric cell

Abstract

The degassing device (100) for a rechargeable electric cell is configured to vary from a closed state to an open state when a predetermined pressing force, induced by a release of gas in the rechargeable electric cell, is exerted on the degassing device (100) in the closed state in order to allow degassing by means of the degassing device (100), the degassing device (100) comprising:  a rupture initiation zone (101) configured to break first when the predetermined pressing force is exerted on the degassing device (100);  two preferential rupture zones (102, 103) extending from the rupture initiation zone (101), and on either side of the rupture initiation zone (101).

Description

Degassing device for rechargeable electric cell Technical field of the invention

[0001] The present invention relates to the technical field of rechargeable electric cells, particularly for vehicles, for example automobiles. Specifically, the invention relates to a degassing device for rechargeable electric cells. Prior art

[0002] When a rechargeable battery cell is used under unforeseen conditions or in the event of a battery cell failure, its temperature can rise above a certain threshold, causing the electrolyte it contains to overheat and potentially lead to thermal runaway. This results in the release of gas, increasing pressure within the battery cell to such an extent that the cell can swell and even burst uncontrollably. This occurs because the battery cell's casing is hermetically sealed to prevent electrolyte loss; the released gas cannot escape, thus generating overpressure within the sealed casing.

[0003] To address this problem, it is known in the field of rechargeable electric cells, particularly prismatic ones, to provide a safety device designed to open to prevent the rechargeable electric cell from bursting in the event of overpressure in the rechargeable electric cell.

[0004] The way in which this security opens is an important issue for manufacturers, particularly with a view to avoiding degradation in the environment of the rechargeable electric cell which may include other rechargeable electric cells or connectors for example between rechargeable electric cells forming a battery. Object of the invention

[0005] The present invention aims to facilitate the degassing of a rechargeable electric cell.

[0006] To this end, the invention relates to a degassing device for a rechargeable electric cell, said degassing device being configured to change from a closed state to an open state when a predetermined pressure force, induced by gas release in the rechargeable electric cell, is exerted on said degassing device in the closed state in order to allow degassing through said degassing device, said degassing device comprising: • a rupture initiation zone configured to rupture first when the predetermined pressure force is applied to said degassing device; • two preferential rupture zones extending from and on either side of the rupture initiation zone; each of the preferential rupture zones comprising: • a first fracture groove extending from the fracture initiation zone, said first fracture groove being straight and configured so that its rupture is caused by a rupture of the fracture initiation zone caused by the predetermined force; • a second rupture groove and a third rupture groove, the second and third rupture grooves each comprising: o a first curved portion extending from one end of said first fracture groove opposite the fracture initiation zone, said first curved portion being configured so that its fracture is caused by the fracture of said first fracture groove; o a second portion in continuity with said first curved portion, said second portion being configured so that its rupture is caused by the rupture of said first curved portion; the two preferential failure zones being configured to delimit two flaps arranged on either side of the first failure grooves and configured to open upon failure of the two preferential failure zones.

[0007] The degassing device may also include one or more of the following features.

[0008] According to a feature of the degassing device, the second portions are straight and are substantially parallel to the first rupture grooves.

[0009] According to a feature of the degassing device, each of the second and third rupture grooves includes an end end of one of the two preferential rupture zones facing one of the end ends of the other of the two preferential rupture zones.

[0010] According to a characteristic of the degassing device, each of the two preferential rupture zones is formed in a hollow within the thickness of said degassing device and has a depth that varies decreasing from the rupture initiation zone.

[0011] According to a feature of the degassing device, the degassing device includes, in the closed state, for each flap, a preferential deformation zone connecting one of the second portions of one of the two preferential rupture zones to one of the second portions of the other of the two preferential rupture zones so as to form a hinge allowing the opening of said flap to be constrained.

[0012] According to a characteristic of the degassing device, the degassing device has, at the periphery of the rupture initiation zone and the two preferential rupture zones, a thickness of between 0.23 mm and 0.27 mm, and: • the rupture initiation zone has a thickness of between 0.10 mm and 0.14 mm; • each preferential failure zone (i.e. preferential failure zone) has a thickness between 0.11 mm and 0.15 mm; Preferably, the thickness of the break initiation zone is strictly less than the minimum thickness of each of the preferential break zones, which helps to promote the start of the break at the break initiation zone.

[0013] According to a feature of the degassing device, the degassing device includes an edge having a thickness between 0.45 mm and 0.55 mm, and, for each of the two preferential break zones, the second and third break grooves of said preferential break zone extend along this edge in opposite directions from the end of the first break groove which they extend.

[0014] The invention also relates to a rechargeable electric cell comprising: • a case; • a cover mounted to the housing so as to delimit an internal compartment; • electrodes and an electrolyte arranged in the internal housing; • a degassing device as described.

[0015] The rechargeable electric cell can be such that the degassing device is: • delimited by a portion of the lid; or • delimited by a portion of the casing; or • a sealing insert, without its closed state, an opening in the lid, or the casing, to which it is mounted.

[0016] The invention also relates to an assembly for a rechargeable electric cell, said assembly comprising a cover intended to be mounted to an opening in a casing of the rechargeable electric cell, the assembly comprising a degassing device as described arranged through the cover. Brief description of the drawings

[0017] The invention will be better understood upon reading the detailed description that follows, given only by way of non-limiting example and made with reference to the drawings attached and listed below.

[0018] Figure 1 represents, from a top view, a degassing device according to one embodiment of the invention.

[0019] Figure 2 shows a perspective view of the degassing device of Figure 1 in a closed state.

[0020] Figure 3 shows a perspective view of the degassing device of Figure 1 in an open state.

[0021] Figure 4 schematically represents a rechargeable electric cell including the degassing device.

[0022] Figure 5 schematically represents a cross-sectional view of the rechargeable electric cell of Figure 4.

[0023] In these figures, the same references are used to designate the same elements. The elements represented in the different figures are not necessarily drawn to scale in order to facilitate understanding of the figures. Detailed description

[0024] By "approximately parallel", it is understood to be parallel or parallel to plus or minus 10 degrees.

[0025] The invention relates to a degassing device 100 for a rechargeable electric cell 1000 (also called a battery cell), a particular embodiment of which is illustrated in figures 1 to 4.

[0026] The degassing device 100 is configured to vary from a closed state (Figures 1, 2 and 4) to an open state (Figure 3) when a predetermined pressure force, induced by a gas release in the rechargeable electric cell 1000, is exerted on said degassing device 100 in the closed state in order to allow degassing through said degassing device 100.

[0027] Degassing specifically involves the release of a gas induced within the rechargeable electric cell by a thermal runaway of the rechargeable electric cell. Thus, the degassing device allows, in particular, for the local separation of the internal and external components of the rechargeable electric cell.

[0028] Typically, this predetermined pressure effort can be between 6 bars and 12 bars.

[0029] The 1000 rechargeable electric cell can be prismatic as shown for example in figure 4.

[0030] The degassing device 100 includes a rupture initiation zone 101 configured to rupture first when a predetermined pressure force is applied to the degassing device 100. "Rupture first" here refers to the ability to localize the initiation of the opening of the degassing device 100 at a very precise location. In other words, the purpose of this rupture initiation zone 101 is to provide a starting point for the opening kinematics of the degassing device 100 so that the transition from its closed to its open state is controlled, in order to prevent the degassing device 100 from bursting and generating projectiles that must be avoided, for obvious safety reasons, in a battery environment that may include a plurality of rechargeable electrical cells 1000.

[0031] The degassing device 100 further includes two preferential rupture zones 102, 103 extending from and on either side of the rupture initiation zone 101. In other words, each of the two preferential rupture zones 102, 103 interfaces with the rupture initiation zone 101. As will be seen later, in order to best control the opening of the degassing device 100, each of the two preferential rupture zones 102, 103 is configured so that its rupture is triggered by a rupture of the rupture initiation zone 101. In other words, each of the two preferential rupture zones 102, 103 is configured to rupture following the rupture of the rupture initiation zone 101.

[0032] Each of the preferential break zones 102 and 103 comprises: • a first rupture groove 1021, 1031 extending from the rupture initiation zone 101, said first rupture groove 1021, 1031 being straight and configured so that its rupture is caused by the rupture of the rupture initiation zone 101 caused by the predetermined pressure force (in other words, each of the two preferential rupture zones 102, 103 is configured to rupture consecutively to, and at the end of, the rupture of the rupture initiation zone 101); • a second rupture groove 1022, 1032 and a third rupture groove 1023, 1033, the second and third rupture grooves 1022, 1032, 1023, 1033 each comprising: o a first curved portion 1022a, 1023a, 1032a, 1033a extending from an end 1021a, 1031a of said first rupture groove 1021, 1031 opposite the rupture initiation zone 101, said first curved portion 1022a, 1023a, 1032a, 1033a being configured so that its rupture is caused by the rupture of said first rupture groove 102, 103 (in other words, each of the first curved portions 1022a, 1023a, 1032a, 1033a is configured to break consecutively to, and at the end of, the rupture of the corresponding first rupture groove 1021, 1031 when the latter has broken to its end 1021a, 1031a); or a second portion 1022b, 1023b, 1032b, 1033b in continuity with said first portion 1022a, 1023a, 1032a, 1033a curved, said second portion 1022b, 1023b, 1032b, 1033b being configured so that its rupture is caused by the rupture of said first curved portion 1022a, 1023a, 1032a, 1033a from which it extends (in other words, each of the second portions 1022b, 1023b, 1032b, 1033b is configured to break consecutively to, and at the end of, the rupture of the first curved portion 1022a, 1023a, 1032a, 1033a from which it extends). The two preferential failure zones 102, 103 are configured to delimit two flaps 104, 105 arranged on either side of the first failure grooves 1021, 1031 and configured to open upon the failure of the two preferential failure zones 102, 103. Specifically, the opening of the flaps 104, 105 corresponds to a displacement of these flaps 104, 105, possibly accompanied by a deformation of these flaps 104, 105, as shown, for example, in Figure 3.

[0033] The presence of the rupture initiation zone 101 combined with the two preferential rupture zones 102, 103 allows control of the propagation of a rupture of the two preferential rupture zones 102, 103 from the rupture initiation zone 101 in case of pressure within the rechargeable electric cell 1000 requiring degassing. In addition, the first curved portions 1022a, 1023a, 1032a, 1033a avoid forming angles so that the propagation of the failure of each of the preferential failure zones 102, 103 occurs progressively from the end 1021a, 103 of the first relevant failure groove 1021, 1031 to the end of the second two 1022b, 1023b, 1032b, 1033b portions of the corresponding preferential failure zone 102, 103.

[0034] Furthermore, each of the first 1021, 1031 rupture grooves can be configured so that its rupture is notably progressive in the sense that it is initiated at its interface with the 101 rupture initiation zone, following the rupture of the 101 rupture initiation zone, before propagating progressively to its end 1021a, 103 la where this triggers the ruptures of the second and third 1022, 1023, 1032, 1033 rupture grooves which extend from this end 1021a, 1031a.

[0035] Thus, for each first rupture groove 1021, 1031, when its rupture reaches its end 1021a, 1031a, the rupture of the corresponding preferential rupture zone 102, 103 continues by propagating progressively along the second and third rupture grooves 1022, 1032, 1023, 1033 arranged in continuity with said first rupture groove 1021, 1031.

[0036] In particular, each of the aforementioned ruptures is a consequence of / caused by the predetermined pressure force applied to the degassing device 100.

[0037] Figure 3 shows in particular the state of the degassing device 100 after rupture of the first and second preferential rupture zones 102, 103: an orifice 110 has been created through the degassing device 100 and allows degassing (arrows Fl).

[0038] The second portions 1022b, 1023b, 1032b, 1033b can be straight, as shown by example in Figures 1 and 2, and are, in this case, substantially parallel to the first fracture grooves 1021, 1031. The first curved portions 1022a, 1023a, 1032a, 1033a are then particularly well suited to connect each of the first straight fracture grooves 1021, 1031 to one of the corresponding second straight portions along a curvature allowing good progression in the fracture of the corresponding preferential fracture zone 102, 103.

[0039] In particular, each of the second and third break grooves 1022, 1023, 1032, 1033 may include a terminal end 1022c, 1023c, 1032c, 1033c of one of the two preferential break zones 102, 103 facing (i.e. turned towards) one of the terminal ends 1022c, 1023c, 1032c, 1033c of the other of the two preferential break zones 102, 103, in particular while being at a distance from said one of the terminal ends 1022c, 1023c, 1032c, 1033c of the other of the two preferential break zones 102, 103.

[0040] This allows for the delimitation of the two flaps 104, 105 arranged on either side of the first rupture grooves 1021, 1031 and each delimited partly by one of the two preferential rupture zones 102, 103 and partly by the other of the two preferential rupture zones 102, 103. Furthermore, this allows each flap 104, 105 to be associated with two end caps between which the material of the degassing device 100 can form a hinge-like articulation through deformation.

[0041] In fact, by "terminal end of a corresponding preferential failure zone," we mean an end where the failure stops when the preferential failure zone ruptures. It is understood from the above description that each of the two preferential failure zones 102, 103 comprises a two-branch derivation (i.e., the corresponding second and third failure grooves 1022, 1023 or 1032, 1033), in particular this derivation is arranged at the end 1021a, 1031a of its first failure groove 1021, 1031. These two branches each terminate in a terminal end: each of the preferential failure zones 102, 103 therefore comprises two terminal ends, in particular located on either side of its first failure groove 1021, 1031.

[0042] In particular, the degassing device 100 is such that it comprises two pairs of second portions (one of the two pairs being represented by the second portions 1022b and 1032b in figures 1 and 2, and the other two pairs being represented by the second portions 1023b and 1033b in figures 1 and 2) co-linear so as to allow good articulation of each of the two flaps 104, 105, the articulations being arranged in particular opposite each other on either side of the first grooves 1021, 1031 of rupture and of the zone 101 of rupture initiation.

[0043] Thus, there is a need to promote the opening of the shutters 104, 105 while ensuring that they remain attached to the rest of the degassing device 100 and that they are contained within a controlled volume in order to optimize the structure of a battery comprising rechargeable electrical cells.

[0044] For this purpose, the degassing device 100 may include, in the closed state and for each flap 104, 105, a zone 106, 107 of preferential deformation connecting one of the second portions 1022b, 1023b of one of the two zones 102 of preferential rupture to one of the second portions 1032b, 1033b of the other of the two zones 103 of preferential rupture so as to form the articulation allowing the opening of said flap 104, 105 to be constrained.

[0045] The presence of the preferential deformation zone 106, 107 makes it possible to constrain the way in which the degassing device 100 will go from its closed state to its open state and thus open the corresponding flap 104, 105.

[0046] Each zone 106, 107 of preferential deformation is preferentially straight and substantially parallel to the first fracture grooves 1021, 1031. Each zone 106, 107 connects, in particular, two terminal ends, each originating from a different zone 102, 103 of preferential fracture.

[0047] For example, each zone 106, 107 of preferential deformation takes the form of a hollow formed in the thickness of the degassing device 100, the depth of which is strictly greater than the depth of the two second portions 1022b, 1032b, 1023b, 1033b that it connects. Preferably, the depth of each zone 106, 107 of preferential deformation is strictly less than the minimum depth of each of the two zones 102, 103 of preferential rupture. The aim is to prevent the rupture of the zones 102, 103 of preferential rupture from propagating to the zones 106, 107 of preferential deformation, which, in the open state, will ensure that the flaps 104, 105 remain connected to the rest of the degassing device 100.

[0048] Each of the two preferential rupture zones 102, 103 can be formed in a hollow within the thickness of the degassing device 100 and can have a depth that varies decreasing from the rupture initiation zone 101.

[0049] The concept of variable depth allows the failure of each of the preferential failure zones 102 and 103 to be guided so that it is progressive. As a result, the failure behavior of the preferential failure zones 102 and 103 is known and controlled in a sensitive environment such as a battery comprising electrically connected rechargeable cells.

[0050] In particular, the variation in depth can be gradual along a constant slope or can occur in steps along the first rupture groove 1021, 1031 and then along the second and third rupture grooves 1022, 1023, 1032, 1033 from the end of the first rupture groove 1021, 1031, from which they extend, each step being associated with a portion of constant depth within the preferred rupture zone 102, 103. The aforementioned slope can also vary by a gradual increase between 1 degree and 10 degrees.

[0051] As described above, each preferred fracture zone 102, 103 can include several ends, one at the interface with the fracture initiation zone 101 and two terminal ends. Specifically, the depth of the reference fracture zone 102, 103 is greatest at its interface with the initiation zone 101 and greatest at its two terminal ends.

[0052] The degassing device 100 may have a thickness of between 0.23 mm and 0.27 mm at the periphery of the rupture initiation zone 101 and the two preferential rupture zones 102 and 103. Preferably, the degassing device 100 may include at least one portion 108 with a maximum thickness of between 0.23 mm and 0.27 mm, which includes, in a recess, the rupture initiation zone 101 and the two preferential rupture zones 102 and 103, formed in particular by a localized reduction in the thickness of the portion 108.

[0053] Specifically, the fracture initiation zone 101 may have a thickness between 0.10 mm and 0.14 mm (measured at the bottom of the fracture initiation zone 101), and each preferred fracture zone 102, 103 may have a thickness between 0.11 mm and 0.15 mm (measured at the bottom of its first, second, and third fracture grooves). Preferably, the thickness of the fracture initiation zone 101 is strictly less than the minimum thickness of each of the preferred fracture zones 102, 103 in order to promote the initiation of fracture at the fracture initiation zone 101.

[0054] Such values ​​are particularly suitable for enabling outgassing in a 1000 rechargeable electric cell, typically when the predetermined effort is reached within the 1000 rechargeable electric cell.

[0055] Part 108 may of course also include the preferential deformation zones 106, 107 which may, where appropriate, have a thickness identical to the maximum thickness of said part 108 or a thickness between 0.18 mm and 0.22 mm so as to form a hollow groove (in particular this thickness is then measured at the level of the bottom of the hollow groove).

[0056] Advantageously, the degassing device 100 may include an edge 109 having a thickness between 0.45 mm and 0.55 mm. In this case, for each of the two preferential failure zones 102, 103, the second and third failure grooves 1022, 1023, 1032, 1033 of said preferential failure zone 102, 103 extend along this edge 109 in opposite directions from the end 1021a, 1031a of the first failure groove 1021, 1031 which said second and third failure grooves 1022, 1023, 1032, 1033 extend.

[0057] This allows for an increase in the length of the second and third rupture grooves 1022, 1023, 1032, 1033. During degassing, the pressure within the rechargeable 1000 electric cell is reduced less abruptly.

[0058] The edge 109 allows, if necessary, for mounting, for example by welding, to a component of the rechargeable electric cell 1000. Furthermore, the greater thickness of the edge 109 stiffens the degassing device 100, thus preventing its failure at its portion 108.

[0059] The edge 109 can be an oval-shaped ring, comprising two opposing curves, for example in the form of two semicircles connected by two straight lines. These two semicircles then determine the curvature of the second and third rupture grooves 1022, 1023, 1032, 1033.

[0060] The 101 rupture initiation zone is notably located in the center of this oval-shaped ring.

[0061] In the event of the presence of the edge 109, the degassing device 100 is in particular a degassing insert to be mounted on an opening of a part of the rechargeable electric cell 1000.

[0062] In a particular example, the oval ring has a longitudinal dimension between 49.7 mm and 49.9 mm and a lateral dimension, measured orthogonally to the longitudinal dimension, between 19.7 mm and 19.9 mm. Specifically, the two semicircles are each delimited by a portion of the outer edge of the oval ring and have centers 30 mm apart in a dimension measured along the direction of measurement of the longitudinal dimension.

[0063] In particular, the two preferential rupture zones 102, 103 can be symmetrical, notably with orthogonal symmetry with respect to a plane passing through the rupture initiation zone 101 and orthogonal to the plane of the degassing device 100.

[0064] Thus, the degassing device 100 may include a plate whose thickness varies to delimit the zones 102, 103 of preferential rupture, the zone 101 of rupture initiation and where applicable the zones 106, 107 of preferential deformation and / or the part 108 and the edge 109.

[0065] As shown in Figures 1 and 2, the degassing device 100 may include slots 111, shaped like grooves, connecting the first groove 1021 to the second and third grooves 1022 and 1023 of the preferential failure zone 102, and slots 112, shaped like grooves, connecting the first groove 1031 to the second and third grooves 1032 and 1033 of the preferential failure zone 103. The role of these slots 111 and 112 is to absorb the material deformation of the degassing device 100 during its manufacturing process.

[0066] Specifically, the first fracture grooves 1021, 1031 of the preferential fracture zones 102, 103 are arranged along the same axis (i.e., are collinear) and are therefore parallel, said axis passing notably through the fracture initiation zone 101. Thus, the first fracture grooves 1021, 1031 extend in opposite directions from the fracture initiation zone 101.

[0067] The invention is of course also related to the rechargeable electric cell 1000, for example as illustrated in figures 4 and 5, comprising: a housing 1001; a cover 1002 mounted to the housing 1001 so as to delimit an internal housing 1006 (i.e. internal to the rechargeable electric cell 1000); electrodes 1003 and an electrolyte 1004 arranged in the internal housing 1006; and the degassing device 100 as described.

[0068] Such a 1000 battery cell has the advantage of being secured in case of overpressure via the 100 degassing device which can open in a controlled manner, thus protecting the environment of the rechargeable 1000 electric cell.

[0069] The 100 degassing device can be: • delimited by a portion of lid 1002, it can then come from the same material as lid 1002; or • delimited by a portion of housing 1001, it can then come from the same material as housing 1002; or • a sealing insert, without its closed state, an opening 1005 of the cover 1002 as for example illustrated in figures 4 and 5, or of the housing 1001, to which it is mounted. These different possibilities are particularly suitable for allowing the degassing of the 100% rechargeable electric cell when necessary.

[0070] The invention also relates to an assembly 1009 for a rechargeable electric cell 1000. This assembly 1009 comprises a cover 1002 intended to be mounted in an opening 1010 of the casing 1001 of the rechargeable electric cell 1000. The assembly 1009 includes a degassing device 100 as described, arranged through the cover 1002 and which may form a portion of the cover 1002 machined in a suitable manner or may take the form of an insert mounted in the opening 1005 of the cover 1002. This embodiment advantageously allows for degassing at the level of the cover 1002 while tending to prevent the loss of the electrolyte 1004 when the cover 1002 is turned away from the ground during the use of the rechargeable electric cell 1000.

[0071] Figures 4 and 5 show the 1000 rechargeable electric cell which is prismatic.

[0072] Specifically, the electrodes 1003 comprise at least one anode and at least one cathode. In this case, said at least one cathode is electrically connected to a positive terminal 1007 of the rechargeable electric cell 1000 via a cathode collector 1111 and said at least one anode is electrically connected to a negative terminal 1008 of the rechargeable electric cell 1000 via an anode collector 1112.

[0073] These positive and negative terminals are notably mounted on cover 1002.

[0074] Generally, the degassing device 100 may include or be made of aluminum. For example, the degassing device 100 is made of AL 1050.

[0075] The present invention finds industrial application in the field of batteries, particularly for electric vehicles. A battery can comprise a plurality of 1000 rechargeable electrical cells.

[0076] An electric vehicle is defined as a vehicle comprising at least one motor to drive one or more of the wheels of the electric vehicle using a battery comprising 1000 rechargeable electric cells as described. Such a vehicle may be 100% electric or a hybrid vehicle also equipped with an internal combustion engine.

Claims

Demands 1. Degassing device (100) for a rechargeable electric cell (1000), said degassing device (100) being configured to change from a closed state to an open state when a predetermined pressure force, induced by gas release in the rechargeable electric cell (1000), is exerted on said degassing device (100) in the closed state to allow degassing through said degassing device (100), said degassing device (100) comprising: • a rupture initiation zone (101) configured to rupture first when the predetermined pressure force is exerted on said degassing device (100); • two preferential failure zones (102, 103) extending from and on either side of the failure initiation zone (101); each of the preferential failure zones (102, 103) comprising: • a first fracture groove (1021, 1031) extending from the fracture initiation zone (101), said first fracture groove (1021, 1031) being straight and configured so that its rupture is caused by a rupture of the fracture initiation zone (101) caused by the predetermined force; • a second rupture groove (1022, 1032) and a third rupture groove (1023, 1033), the second and third rupture grooves (1022, 1032, 1023, 1033) each comprising: o a first curved portion (1022a, 1023a, 1032a, 1033a) extending from one end (1021a, 1031a) of said first fracture groove (1021, 1031) opposite the fracture initiation zone (101), said first curved portion (1022a, 1023a, 1032a, 1033a) being configured so that its fracture is caused by the fracture of said first fracture groove (1021, 1031); o a second portion (1022b, 1023b, 1032b, 1033b) in continuity with said first portion (1022a, 1023a, 1032a, 1033a) curved, said second portion (1022b, 1023b, 1032b, 1033b) being configured so that its rupture is caused by the rupture of said first portion (1022a, 1023a, 1032a, 1033a) curved; the two preferential failure zones (102, 103) being configured to delimit two flaps (104, 105) arranged on either side of the first failure grooves (1021, 1031) and configured to open upon failure of the two preferential failure zones (102, 103).

2. Degassing device (100) according to claim 1, wherein the second portions (1022b, 1023b, 1032b, 1033b) are straight and are substantially parallel to the first rupture grooves (1021, 1031).

3. Degassing device (100) according to any one of claims 1 to 2, wherein each of the second and third rupture grooves (1022, 1023, 1032, 1033) comprises a terminal end (1022c, 1023c, 1032c, 1033c) of one of the two preferential rupture zones (102, 103) facing one of the terminal ends (1022c, 1023c, 1032c, 1033c) of the other of the two preferential rupture zones (102, 103).

4. Degassing device (100) according to claim 1, in which each of the two preferential rupture zones (102, 103) is formed in a hollow in the thickness of said degassing device (100) and has a depth varying by decreasing from the rupture initiation zone (101).

5. Degassing device (100) according to any one of claims 1 to 4, comprising in the closed state, for each flap (104, 105), a zone (106, 107) of preferential deformation connecting one of the second portions (1022b, 1023b) of one of the two zones (102) of preferential rupture to one of the second portions (1032b, 1033b) of the other of the two zones (103) of preferential rupture so as to form a hinge allowing the opening of said flap (104, 105) to be constrained.

6. A degassing device (100) according to any one of claims 1 to 5, having, at the periphery of the rupture initiation zone (101) and the two preferential rupture zones (102, 103), a thickness of between 0.23 mm and 0.27 mm, and wherein: • the (101) break initiation zone has a thickness between 0.10 mm and 0.14 mm; • Each preferential break zone (102, 103) has a thickness between 0.11 mm and 0.15 mm.

7. Degassing device (100) according to claim 6, comprising an edge (109) having a thickness between 0.45 mm and 0.55 mm, and in which, for each of the two preferential break zones (102, 103), the second and third break grooves (1022, 1023, 1032, 1033) of said preferential break zone (102, 103) extend along this edge (109) in opposite directions from the end (1021a, 1031a) of the first break groove (1021, 1031) which they extend.

8. Rechargeable electric cell (1000) comprising: • a case (1001); • a cover (1002) mounted to the housing (1001) so as to delimit an internal compartment (1006); • electrodes (1003) and an electrolyte (1004) arranged in the internal housing (1006); • a degassing device (100) according to any one of claims 1 to 7.

9. Rechargeable electric cell (1000) according to claim 8, wherein the degassing device (100) is: • delimited by a portion of the lid (1002); or • delimited by a portion of the casing (1001); or • a sealing insert, without its closed state, an opening (1005) in the cover (1002), or in the housing (1001), to which it is mounted.

10. Assembly (1009) for rechargeable electric cell (1000), said assembly (1009) comprising a cover (1002) intended to be mounted to an opening in a housing (1001) of the rechargeable electric cell (1000), the assembly (1009) comprising a degassing device (100) according to any one of claims 1 to 7 arranged through the cover (1002).

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