Cylindrical battery cell having at least one safety member

Abstract

The cylindrical battery cell (100) comprises: • a body (105) comprising a bottom (106) and an opening (107) located on the opposite side from the bottom (106); • a cover (108) hermetically fastened to the opening (107); • a winding of electrodes (103) arranged in the body (105) and electrically connected to first and second poles (101, 102) of the cylindrical battery cell (100). The cover (108) comprises at least one safety member (109a, 109b) delimiting a portion of the outer surface of the battery cell (100), said at least one safety member being configured to vary from a closed state to an open state when a predetermined pressure force is exerted on said at least one safety member in the closed state in order to create a degassing orifice.

Description

Cylindrical battery cell with at least one safety device Technical field of the invention

[0001] The present invention relates to the technical field of batteries, particularly for vehicles, for example automobiles. In particular, the invention relates to a cylindrical battery cell. Prior art

[0002] A cylindrical battery cell is known to comprise: a winding of electrodes; an electrolyte; and an elongated body forming the negative terminal of the cylindrical battery cell. This body includes a base and a side wall extending from the base along the length of the elongated body, thus defining a compartment in which the electrode winding and the electrolyte are arranged. Opposite the base, the body is closed by a cover forming the positive terminal of the cylindrical battery cell.

[0003] When using the cylindrical battery cell under unintended conditions or in the event of failure of the cylindrical battery cell, the temperature of the cylindrical battery cell may rise above a threshold such that the electrolyte will cause thermal runaway, inducing the release of a gas which increases the pressure within the cylindrical battery cell in a way which may lead to swelling of the cylindrical battery cell and may even cause an uncontrolled bursting of the cylindrical battery cell.

[0004] Indeed, since the body is hermetically sealed to prevent the loss of the electrolyte, the gas released cannot be evacuated and therefore generates overpressure within the closed body.

[0005] To address this issue, a fusible safety membrane is used. This membrane seals the housing hermetically on the lid side during normal operation but ruptures if the pressure inside the housing exceeds a predetermined value. This fusible safety membrane is positioned behind the lid, which has vents to allow gas to escape from the cylindrical battery cell if the membrane ruptures.

[0006] Thus, the fusible safety membrane is arranged in a dead volume between the housing and the cover.

[0007] Dead volume refers to a volume that does not contribute to the energy capacity of the cylindrical battery cell, thus reducing the energy density per unit volume of the cylindrical battery cell. In a complete battery comprising a plurality of cylindrical battery cells, the presence of fusible safety membranes limits the battery's energy density per unit volume. This can have a significant impact on the driving range of a motor vehicle using such a battery as its power source. Object of the invention

[0008] The invention relates to a solution allowing outgassing of a cylindrical battery cell while allowing the cylindrical battery cell to exhibit a satisfactory energy density.

[0009] To this end, the invention relates to a cylindrical battery cell comprising: • a first pole and a second pole of opposite signs; • a body comprising a base and an opening arranged opposite said base, the first pole comprising at least part of said body; • a lid fixed hermetically to the opening, the second pole comprising at least part of the lid; • a coil of electrodes arranged in the body and electrically connected to the first and second poles; • an electrolyte arranged in the body; the cover comprising at least one safety device delimiting a portion of the outer surface of the cylindrical battery cell, said at least one safety device being configured to vary from a closed state to an open state when a predetermined pressure force, induced by a gas release in the body, is exerted on said at least one safety device in the closed state in order to create a venting orifice through the cover, said at least one safety device comprising, in the closed state of said at least one safety device, a preferential rupture zone configured to rupture when said predetermined pressure force is exerted on said at least one safety device, the preferential rupture zone taking the form of a continuous line having two opposite longitudinal ends distant from each other.

[0010] This has the advantage of allowing effective degassing in case of overpressure in the cylindrical battery cell.

[0011] The cylindrical battery cell may also include one or more of the following features.

[0012] According to a characteristic of the cylindrical battery cell, the cover includes a plate mounted at its periphery at the opening in a hermetically sealed manner, the plate including said at least one safety device.

[0013] According to a characteristic of the cylindrical battery cell, the plate is fixed by welding to the opening so that the first pole includes the plate, said plate being of one piece.

[0014] According to a characteristic of the cylindrical battery cell, the cover includes a connecting element electrically linked to the electrode winding, said connecting element being: • formed by a portion, in particular the central portion of the plate, said plate constituting the lid; or mounted through a through hole formed in the plate, the cover comprising an electrically insulating element interposed between the plate and the connecting element, the second pole comprising the connecting element.

[0015] According to a characteristic of the cylindrical battery cell, the preferential failure zone of said at least one safety device is formed by a localized thinning of the cover.

[0016] According to a characteristic of the cylindrical battery cell, said at least one safety device comprises, in its closed state, a preferential deformation zone connecting the two opposite longitudinal ends of said continuous line.

[0017] According to a characteristic of the cylindrical battery cell, said line continues: • comprises two segments forming an angle with each other and connected by a curved portion of said continuous line, said curved portion being proximal to the connecting organ; or • comprises a segment including first and second opposing longitudinal extremities, the first longitudinal extremity of the segment being proximal to the connecting organ, and a curved portion extending continuously from the second longitudinal extremity of the segment; or • is at least mostly curved, for example in the manner of an arc of a circle.

[0018] According to a characteristic of the cylindrical battery cell, said at least one safety device is configured such that, at any time during the transition from its closed state to its open state, any point of said at least one safety device is arranged at a level: • located between a first level defined by the bottom of the body and a second level defined by a vertex of the distal connecting organ of the bottom of the body; • at a distance from the second level.

[0019] According to a characteristic of the cylindrical battery cell, the cover includes several safety devices.

[0020] According to a characteristic of the cylindrical battery cell, the preferential breakage zones have the same shape and are distributed at regular intervals around the connecting element.

[0021] According to a characteristic of the cylindrical battery cell, the preferential failure zone takes the form of a groove such as: • the groove depth is between 70% and 95% of the lid thickness at the periphery of the groove; and / or • the longitudinal ends of the preferential breaking zone are separated by a distance greater than or equal to ten times the thickness of the cover at the periphery of the groove; and / or • the length of the groove is between 10% and 60% of the perimeter of the lid.

[0022] According to a characteristic of the cylindrical battery cell, the cover includes a connection element electrically linked to the electrode winding, said at least one safety element being configured such that, at any time during the transition from its closed state to its open state, any point of said at least one safety element is arranged at a level: • located between a first level defined by the bottom of the body and a second level defined by a vertex of the distal connecting organ of the bottom of the body; • at a distance from the second level. This ensures that the opening of at least one safety device does not impact the connections of the cylindrical battery cell.

[0023] Other features and benefits may emerge from the detailed description that follows. Brief description of the drawings

[0024] The invention will be better understood upon reading the detailed description that follows, given only as a non-limiting example and made with reference to the attached drawings listed below.

[0025] Figure 1 schematically represents a cross-sectional view of a cylindrical battery cell according to an embodiment of the invention; in this figure 1, the cylindrical battery cell includes a cover equipped with two safety devices, each in a closed state.

[0026] Figure 2 schematically represents a cross-sectional view of the cylindrical battery cell of Figure 1 in which both safety devices are each in an open state.

[0027] Figure 3 represents an embodiment of the invention, according to a perspective view, in which a cover plate comprises four safety devices, each in the closed state.

[0028] Figure 4 shows, in perspective view, the plate of figure 3 for which the safety devices are each in the open state.

[0029] Figure 5 represents, in perspective view, another embodiment of the plate in which the two safety devices are each in the closed state.

[0030] Figure 6 represents, in perspective view, the plate of the type of figure 5 whose safety devices are each in the open state.

[0031] Figure 7 shows, in perspective view, another embodiment of the plate in which the four safety devices are each in the closed state.

[0032] Figure 8 represents, in perspective view, the plate of figure 7 whose safety devices are each in the open state.

[0033] 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

[0034] In this detailed description, "between two values" means that the corresponding range of values ​​includes said two values.

[0035] The invention relates to a cylindrical battery cell 100, a particular embodiment of which is illustrated in Figures 1 and 2 respectively, in two different configurations of the cylindrical battery cell 100. These two configurations, referred to respectively as closed (Figure 1) and open (Figure 2), are detailed below.

[0036] Generally, a battery module may comprise a plurality of cylindrical battery cells 100 as described, and an electrical connection system linking the cylindrical battery cells 100 together, particularly on the side of a cover 108 of the battery cell 100. A battery specifically comprises battery cells 100 or a plurality of battery modules as described, electrically connected together.

[0037] The cylindrical battery cell 100 comprises a first pole 101 and a second pole 102 of opposite signs.

[0038] The first and second poles 101 and 102 are electrical poles, each with a polarity chosen from a positive pole (connected to at least one cathode of the cylindrical battery cell 100) and a negative pole (connected to at least one anode of the cylindrical battery cell 100). These poles are accessible from outside the cylindrical battery cell 100, thus allowing for reconnection to the cylindrical battery cell 100. These first and second poles 101 and 102 form connection terminals for the cylindrical battery cell 100, specifically designated as the negative terminal for the first pole 101 and the positive terminal for the second pole 102.

[0039] The cylindrical battery cell 100 comprises a winding 103 of electrodes electrically connected to the first and second poles 101, 102.

[0040] Conventionally, the electrode winding 103 can be formed by winding a multilayer material onto itself, comprising successively a first electrode sheet (for example, an anode of the electrode winding 103), a first separator sheet, a second electrode sheet (for example, a cathode of the electrode winding 103) of opposite polarity to the first electrode sheet, and a second separator sheet. This allows the electrode winding 103 to be formed while keeping the anode and cathode of the electrode winding 103 separated and allowing the electrolyte 104 of the cylindrical battery cell 100 to be impregnated within the first and second separator sheets.

[0041] The cylindrical battery cell 100 comprises a body 105. This body 105 comprises a base 106 and an opening 107 arranged opposite said base 106.

[0042] The first pole 101 includes at least part of the body 105. Preferably, the first pole 101 includes the body 105 which is then electrically conductive and, preferably, electrically connected to the anode of the electrode winding 103.

[0043] According to the preferred embodiment shown in Figures 1 and 2, the body 105 can be a hollow cylinder made of a metallic material including steel. Such a material is chosen for its electrical conductivity and, where appropriate, its ease of welding.

[0044] Typically, the cylindrical battery cell 100 has a circular cross-section taken between the bottom 106 and the opening 107.

[0045] Preferably, the body 105 is a straight circular cylinder. The opening 107 can therefore adopt a circular profile.

[0046] The body 105 can be a single piece or formed by assembling parts, for example welded together.

[0047] The electrode winding 103 described above is arranged in the body 105.

[0048] The cylindrical battery cell 100 includes the cover 108 hermetically mounted / fixed to the opening 107, the second pole 102 comprising at least a portion of the cover 108.

[0049] The electrolyte 104 of the cylindrical battery cell 100 is arranged in the body 105. In particular, the electrode winding 103 is immersed in this electrolyte 104.

[0050] Electrolyte 104 acts as a conductor allowing ions to circulate, in particular between the first and second electrode sheets of the electrode winding 103.

[0051] The cover 108 includes at least one safety device 109a, 109b, 109c, 109d (see in particular Figures 1 to 8) delimiting a portion of the outer / extreme surface of the cylindrical battery cell 100. This at least one safety device 109a, 109b, 109c, 109d is configured to have a closed state and an open state. Said at least one safety device 109a, 109b, 109c, 109d is configured to vary from its closed state to its open state when a predetermined pressure force Fl (Figure 1), induced by a gas release in the body 105 (for example caused by a thermal runaway of the cylindrical battery cell 100) is exerted on said at least one safety device 109a, 109b, 109c, 109d in the closed state in order to create a degassing orifice 110 through the cover 108.

[0052] Of course, in the closed state of said at least one safety device 109a, 109b, 109c, 109d, gas cannot pass through said at least one safety device 109a, 109b, 109c, 109d. In the open state of said at least one safety device 109a, 109b, 109c, 109d, the latter allows fluid communication from the inside of the cylindrical battery cell 100 to the outside of the cylindrical battery cell 100.

[0053] Thus, in the event of thermal runaway of the cylindrical battery cell 100, the gas released in the body 105, which is then closed at the opening 107 by the cover 108, can, when the conditions are met, induce the predetermined pressure force Fl necessary to create the degassing orifice 110 through which the gas G1 (represented schematically by three wavy lines in figure 2) will be able to escape.

[0054] It is in this sense that the transition from figure 1 to figure 2 shows the transition from the closed configuration of the cylindrical 100 battery cell to the open configuration of the cylindrical 100 battery cell.

[0055] It follows from the foregoing that, generally, said at least one safety device 109a, 109b, 109c, 109d allows, where necessary, the evacuation of gas G1 from the inside of the cylindrical battery cell 100 to the outside of the cylindrical battery cell 100 in the event of overpressure. Furthermore, the presence of said at least one safety device 109a, 109b, 109c, 109d on the outer surface of the cylindrical battery cell 100, directly at the level of the cover 108, reduces the overall size of the cylindrical battery cell 100 by avoiding the presence of a dead volume as defined in the prior art section.

[0056] In particular, the cover 108 has a face facing outwards from the cylindrical battery cell 100 and contributing to defining the overall volume of the cylindrical battery cell 100. This face includes the portion of the external surface of the cylindrical battery cell 100 that is delimited by at least one safety device 109a, 109b, 109c, 109d.

[0057] According to one embodiment, the cover 108 can be made at least partly from an electrically conductive material, preferably metallic such as steel.

[0058] In a preferred embodiment, the cover 108 includes a shape enabling it to fit onto the opening 107, for example, to be welded thereto. If necessary, at least a portion of the cover 108, or element of the cover 108, may have the shape of a right circular cylinder (i.e., a disc shape).

[0059] For example, the cover 108 includes a plate 113, in particular forming said element of the cover 108. This plate 113 is then mounted at its periphery at the opening 107 in a hermetically sealed manner, for example by welding, the plate 113 including said at least one safety device 109a, 109b, 109c, 109d.

[0060] The presence of such a plate 113 is advantageous because it allows, by integrating said at least one safety device 109a, 109b, 109c, 109d, to avoid the presence of a dead volume dedicated to degassing in the cylindrical battery cell 100.

[0061] For example, plate 113 is welded to opening 107 so that the first pole 101 includes plate 113, this plate 113 being a single piece. Thus, plate 113 is preferentially electrically conductive.

[0062] This has the advantage that the plate 113 and the body 105 can be welded together at the opening 107 to ensure electrical continuity. Preferably, for this purpose, the body 105 and the plate 113 are made of the same material.

[0063] The cover 108 may include a connecting member 114 (which is, of course, electrically conductive) electrically connected to the electrode winding 103, for example to the cathode of the electrode winding 103, said connecting member 114 being: formed by a portion, particularly a central one, of plate 113, said plate 113 constituting the cover 108, this avoids having a through hole in the cover 108; or • mounted through a through hole 115 formed in the plate 113, the cover 108 comprising an electrically insulating element 116, such as a seal, interposed between the plate 113 and the connection element 114, the second pole 102 comprising the connection element 114, thus making accessible in particular the first and second poles 101, 102 of the cylindrical battery cell 100 on the same face at the level of the cover 108.

[0064] In particular, the through hole 115 is arranged in a central region of the plate 113. When the plate 113 takes the form of a disk, the through hole 115 and the disk are preferably coaxial.

[0065] The connecting member 114 may be a rivet passing through the plate 113 via the open hole 115 and electrically connected to the electrode winding 103.

[0066] Advantageously, the cover 108, in particular the plate 113, can include several safety devices 109a, 109b, 109c, 109d.

[0067] This has the effect of increasing the release rate of gas G1 through the simultaneous opening of the safety devices 109a, 109b, 109c, and 109d in the event of overpressure within the cylindrical battery cell 100 in its closed configuration. In other words, the predetermined pressure force Fl is preferably the same for each of the safety devices 109a, 109b, 109c, and 109d in order to allow their simultaneous opening.

[0068] In addition, the presence of several safety devices 109a, 109b, 109c, 109d also helps to reduce the risk of uncontrolled explosion of the cylindrical battery cell 100 in the sense that if one of the safety devices 109a, 109b, 109c, 109d does not open in the event of overpressure in the cylindrical battery cell 100, then at least one other, or all of the others, can take over.

[0069] In this description, everything described in relation to a 109a, 109b, 109c, 109d safety device can be applied to each of the 109a, 109b, 109c, 109d safety devices.

[0070] In figures 3 to 8, the cover 108 includes the plate 113 including the through hole 115, the connecting member 114 and the electrically insulating member 116 have not been shown for clarity.

[0071] Figures 1, 2, 5 and 6 show in part the cover 108 comprising two safety devices 109a, 109b.

[0072] Figures 3, 4, 7 and 8 show in part the cover 108 comprising four safety devices 109a, 109b, 109c, 109d.

[0073] Of course, a single safety device may suffice to carry out degassing when necessary, although a solution with several safety devices 109a, 109b, 109c, 109d (i.e. at least two) is preferred.

[0074] Of course, when the safety device in the case where it is alone, or when all the safety devices 109a, 109b, 109c, 109d, are in the closed state, the cylindrical battery cell 100 is hermetically sealed (i.e. in its closed configuration) so as to prevent any fluidic communication (gas and / or electrolyte) between the inside and outside of the cylindrical battery cell 100.

[0075] According to the invention, said at least one safety device 109a, 109b, 109c, 109d comprises, in the closed state of said at least one safety device 109a, 109b, 109c, 109d, a preferential rupture zone 111 configured to rupture when said predetermined pressure force Fl is exerted on said at least one safety device 109a, 109b, 109c, 109d.

[0076] This allows, during an overpressure inside the cylindrical 100 battery cell then in its closed configuration, to obtain a controlled and localized rupture on a predetermined area in order to control the deformation of the cylindrical 100 battery cell so that this deformation does not impact other components (for example the electrical connection system) within a battery integrating a plurality of cylindrical 100 battery cells as described.

[0077] The preferential break zone 111 takes the form of a continuous line 111a having two longitudinal ends 111b, 111c opposite and distant from each other.

[0078] One advantage of such a continuous line 111a is that it allows control over the opening of at least one safety device 109a, 109b, 109c, 109d, while also promoting the retention of the material constituting said at least one safety device 109a, 109b, 109c, 109d during the transition from its closed to its open state. This helps to prevent the ejection of debris away from the cylindrical battery cell 100 in the event of overpressure in the body 105 of the cylindrical battery cell 100. Furthermore, it also prevents the expulsion of macroscopic materials from inside the cylindrical battery cell 100, since its explosion is prevented by the opening of said at least one safety device 109a, 109b, 109c, 109d.

[0079] Furthermore, this can allow a reduction (or even avoid the presence), along a longitudinal axis Al of the cylindrical battery cell 100 represented in figures 1 and 2, of the dead volume as defined in the prior art section since the cover 108 can be closer to the electrode winding 103.

[0080] Furthermore, such a continuous line 111a makes it possible to constrain the deformation of said at least one safety device 109a, 109b, 109c, 109d, and thus the maximum height, relative to the bottom 106, that said at least one safety device 109a, 109b, 109c, 109d can reach once opened. This allows for easier integration of the cylindrical battery cell 100 within a battery, or battery module, while taking into account the opening of its safety device(s) 109a, 109b, 109c, 109d.

[0081] The manufacture of the cover 108 is advantageously done in a simple and high-speed manner in the sense that creating a zone of weakness (i.e. the preferential breaking zone), particularly in the form of a line, can be done at high speed.

[0082] As can be seen by way of example in Figures 1, 3, 5, and 7, each preferential failure zone 111 exists in the closed state of the corresponding safety device 109a, 109b, 109c, 109d. As can be seen in Figures 2, 4, 6, and 8, each preferential failure zone 111 has ruptured, i.e., the corresponding safety devices 109a, 109b, 109c, 109d are shown in the open state.

[0083] Advantageously, the preferential break zone 111 of said at least one safety device 109a, 109b, 109c, 109d is formed by a localized thinning of the cover 108, and where applicable of the plate 113.

[0084] This makes it possible to induce ease of manufacture and integration of said at least one safety device 109a, 109b, 109c, 109d by simply carrying out local thinning operations of the cover 108. With such a solution, the bulk induced by the presence of said at least one safety device 109a, 109b, 109c, 109d has little or no impact on the overall bulk of the cylindrical battery cell 100 since it is formed in the thickness of the cover 108: there is no need to add a specific degassing element (such as a fusible safety membrane) between the cover and the electrode winding.

[0085] As shown in Figure 1, a non-through material removal from the plate 113 can be performed to obtain the preferential rupture zone(s) 111. The non-through nature of the removal ensures the sealing of the cylindrical battery cell 100 to prevent the loss of electrolyte 104 when the safety device(s) 109a, 109b, 109c, 109d are in the closed state.

[0086] According to various non-limiting embodiments, several manufacturing processes can be used to enable the realization of this localized thinning, such as a machining, stamping or laser process for example implemented before mounting / fixing the cover 108 to the body 105.

[0087] According to different embodiments, in the case of localized thinning achieved by machining, several shapes of the thinning can be achieved, according to a cross-sectional view of the plate 113, such as a U-shape or a V-shape. A representation of a U-shape is illustrated in Figure 1.

[0088] According to one embodiment, in the closed state of said at least one corresponding safety device 109a, 109b, 109c, 109d, its continuous line 111a is included in the plane of a first face of the cover 108, where appropriate of the plate 113, turned outwards from the cylindrical battery cell 100 (see for example Figures 1 and 2).

[0089] Alternatively, in the closed state of said at least one corresponding safety device 109a, 109b, 109c, 109d, its continuous line 111a is included in the plane of a second face of the cover 108, and where applicable, of the plate 113, facing the bottom 106 of the body 105 of the cylindrical battery cell 100. The first and second faces of the cover 108 are opposite.

[0090] Specifically, a continuous line is understood to mean one without discontinuities along its entire length. In this sense, the preferred break zone(s) 111 is preferably a groove, notably formed in the thickness of the plate 113.

[0091] Specifically, for each preferential rupture zone 111, the groove forming said preferential rupture zone 111 may have a constant or variable depth between the two opposing longitudinal ends 111b, 111c of its continuous line 111a. With a variable depth, it is possible to orient the rupture in the correct direction and control the rupture speed of the line, thus allowing the cylindrical battery cell 100 to be designed in a way that the opening of the safety device(s) 109a, 109b, 109c, 109d will occur.

[0092] For example, the diameter of the cylindrical 100 battery cell is 46 mm.

[0093] Preferably, the cover 108 or said at least part of the cover 108, and in particular the plate 113, has a thickness between 0.2 mm and 1 mm and for example equal to 0.6 mm.

[0094] Preferably, for the preferred failure zone(s) 111, it takes the form of a groove such that: • the groove depth is between 70% and 95% of the thickness of the cover 108 at the periphery of the groove (i.e., at the interface of the crests of the groove walls – opposite the bottom of the groove – with the rest of the cover 108 or, more particularly, the plate 113); and / or • the longitudinal ends of said preferential breaking zone 111 are separated by a distance greater than or equal to ten times the thickness of the cover 108 from the periphery of the groove (in particular ten times the thickness of the plate 113 outside the preferential breaking zone(s) 111, i.e. the maximum thickness of the plate 113); and / or • the length of the groove is between 10% and 60% of the perimeter P of the cover 108 (in particular its edge), in particular of the plate 113 (in particular its edge), and more particularly this perimeter P corresponding to the perimeter of the opening 107. Each of these features helps to improve the safety of the cylindrical battery cell 100 by tending to prevent the explosion of the cover 108.

[0095] In particular, limiting the groove width makes the cover 108 more robust, thus preventing it from cracking outside the corresponding preferential failure zone 111. This could lead to uncontrolled cover rupture, causing electrolyte to be ejected and / or damaging nearby cylindrical battery cells. For this purpose, the groove width can be between 0.1 mm and 1 mm. Furthermore, the groove can have a V-shaped profile such that the longitudinal walls of the groove are angled between 60 degrees and 110 degrees.

[0096] Said at least one safety device 109a, 109b, 109c, 109d may advantageously include, in its closed state, a zone 112 of preferential deformation (schematized in dotted lines for one of the safety devices in figures 3, 5 and 7) connecting the two opposite longitudinal ends 111b, 111c of the continuous line 111a of the zone 111 of preferential rupture of said at least one safety device 109a, 109b, 109c, 109d.

[0097] This enables the creation of the corresponding degassing orifice 110 because, once the relevant preferential rupture zone 111 has given way / broken, the associated preferential deformation zone 112 will allow the corresponding safety device 109a, 109b, 109c, 109d to bend / deform locally in a controlled manner in order to allow the gas internal to the cylindrical battery cell 100 to escape. Furthermore, this allows, in the open state of the corresponding safety device 109a, 109b, 109c, 109d, to connect the corresponding safety device 109a, 109b, 109c, 109d to the rest of the cover 108, preventing this corresponding safety device 109a, 109b, 109c, 109d from being projected freely into the environment outside the cylindrical battery cell 100.

[0098] The deformation of the or each zone 112 of preferential deformation is made possible in particular by the thickness considered of the cover 108 at its level, or of the thickness considered of said plate 113 at its level, which then makes it possible to confer locally a hinge function to said zone 112 of preferential deformation.

[0099] More specifically, the preferential deformation zone 112 can be defined, for example, by a segment connecting the two opposite longitudinal ends 111b, 111c of the corresponding continuous line 111a. This preferential deformation zone 112 can deform elastically or plastically during the transition from the closed to the open state of the corresponding safety device 109a, 109b, 109c, 109d.

[0100] Thus, it follows from what has been described above that, for each preferential break zone 111, the corresponding continuous line 111a can: • comprising two segments 117a, 117b forming an angle between them and connected by a curved portion 117c of said continuous line 111a, said curved portion 117c being proximal to the connecting organ 114 and, where applicable, to the opening 115 (see in particular Figure 7 for this purpose); or • include (see in particular in this regard Figure 3) a segment 118 comprising first and second opposing longitudinal ends 118a, 118b (for example, one of which corresponds to one of the opposite longitudinal ends of the continuous line 111a), the first longitudinal end 118a of segment 118 being proximal to the connecting organ 114 and, where applicable, to the opening 115, and include a curved portion 119 extending continuously from the second longitudinal end 118b of segment 118 (and this curved portion 119 comprising, for example, the other of the opposite longitudinal ends of the continuous line 111a); or • is at least mostly curved, for example in the manner of an arc of a circle (see in particular in this sense figure 5 where the convex part of the arc of a circle is predominant and turned away from the connecting member 114 and where applicable the opening hole 115, the arc of a circle being able to continue at its two ends by segments one in the direction of the other).

[0101] These different realizations of the continuous line 111a each allow to constrain the way in which the safety device 109a, 109b, 109c, 109d will open while limiting the bulk associated with this opening along the longitudinal axis Al of the cylindrical battery cell 100 (this longitudinal axis Al, although not shown in figures 3, 5 and 7, would preferably be orthogonal to the plane of the plate 113).

[0102] By "at least mostly curved", it is understood that the continuous line 111a may be entirely curved or that depending on the length of the continuous line 111a, a portion of the continuous line 111a is curved and represents more than 50% of the length of the continuous line 111a.

[0103] The possibility of limiting the bulk generated by at least one safety device 109a, 109b, 109c, 109d during its opening was mentioned above. To this end, and as illustrated for example in Figures 1 and 2, said at least one safety device 109a, 109b, 109c, 109d can be configured so that, at any time during the transition from its closed state to its open state, any point / any part of said at least one safety device 109a, 109b, 109c, 109d is arranged at a level: • located between a first level L1 defined by the bottom 106 of the body 105 and a second level L2 defined by a vertex of the organ 114 of distal connection of the bottom 106 of the body 105; • at a distance from the second level L2.

[0104] This ensures that opening at least one of the safety devices 109a, 109b, 109c, 109d does not affect the connections of the cylindrical battery cell 100, particularly within the battery module or the battery itself. It is therefore possible to design a suitable battery module architecture that allows its cylindrical battery cells 100 to be connected to each other without affecting these connections if one or more safety devices 109a, 109b, 109c, 109d within the battery module are opened.

[0105] In particular, the first level L1 may correspond to a first plane defined by a face of said base 106 turned inwards towards the cylindrical battery cell 100, and the second level L2 corresponds to a second plane parallel to the first plane. The second plane passes through the apex of the connecting member 114. In this case, said at least one safety member 109a, 109b, 109c, 109d, regardless of the state of said at least one safety member 109a, 109b, 109c, 109d chosen from the closed state and the open state, always remains between the first and second levels L1 and L2 and at a distance from these first and second levels L1 and L2. These first and second planes may be planes orthogonal to the longitudinal axis A1.

[0106] Preferably, in the closed state of said at least one safety device 109a, 109b, 109c, 109d, the latter comprises a sealing portion 120, also called a flap, extending between / connecting the preferred deformation zone 112 and the preferred rupture zone 111. The transition from the closed state to the open state of said at least one safety device 109a, 109b, 109c, 109d results in a displacement of its sealing portion 120, in particular such that said sealing portion 120 forms an angle with the plane of the plate 113 considered before said transition.

[0107] Advantageously, the preferential break zones 111 have the same shape (i.e., in particular, all have the same shape) and are distributed at regular intervals around the connecting organ 114.

[0108] The advantage provided is improved control over the failure of the preferential failure zones 111. This allows for smaller components 109a, 109b, 109c, and 109d, thereby reducing the risk of premature opening if the cylindrical battery cell 100 is exposed to heat. Another advantage is that the repeatability of the shapes of the preferential failure zones 111 is well-suited to mass production.

[0109] For example, as seen in Figure 3 and Figure 7 respectively, four preferential break zones 111 are identical and are distributed at 90-degree angles around the connecting member 114. Thus, the preferential break zones 111 are symmetrical with respect to the central point of the circular plate 113 of the cover 108, in particular through which the open hole 115 passes.

[0110] The battery mentioned above is preferably a battery for a motor vehicle and intended to serve as a power source for an electric motor of the motor vehicle enabling the movement of the motor vehicle (also called an "electric vehicle" such as a 100% electric vehicle or a plug-in hybrid vehicle or not) for example: • by propulsion or traction via two drive wheels of the vehicle; or • by all-wheel drive via four drive wheels of the vehicle in particular when two electric motors of the vehicle, powered by the battery, are coupled respectively to a front axle of the motor vehicle comprising two of the wheels of the motor vehicle and to a rear axle of the motor vehicle comprising two other of the wheels of the motor vehicle. [yes] The cylindrical 100 battery cell as described has an industrial application in the field of the battery industry, particularly in the automotive field.

Claims

Demands 1. Cylindrical battery cell (100) comprising: • a first pole (101) and a second pole (102) of opposite signs; • a body (105) comprising a base (106) and an opening (107) arranged opposite said base (106), the first pole (101) comprising at least part of said body (105); • a cover (108) hermetically fixed to the opening (107), the second pole (102) comprising at least a part of the cover (108); • a winding (103) of electrodes arranged in the body (105) and electrically connected to the first and second poles (101, 102); • an electrolyte (104) arranged in the body (105); the cover (108) comprising at least one safety device (109a, 109b, 109c, 109d) delimiting a portion of the outer surface of the cylindrical battery cell (100), said at least one safety device (109a, 109b, 109c, 109d) being configured to change from a closed state to an open state when a predetermined pressure force (Fl), induced by gas release in the body (105), is exerted on said at least one safety device (109a, 109b, 109c, 109d) in the closed state in order to create a degassing orifice (110) through the cover (108), said at least one safety device (109a, 109b, 109c, 109d) comprising, in the closed state of said at least one device (109a, 109b, 109c, 109d) safety device, a preferred rupture zone (111) configured to rupture when said predetermined pressure force (Fl) is exerted on said at least one safety device (109a, 109b, 109c, 109d),the preferential breaking zone (111) taking the form of a continuous line (111a) having two opposite longitudinal ends (111b, 111c) distant from each other, the cover (108) comprising a connecting element (114) electrically connected to the electrode winding (103), said at least one safety element (109a, 109b, 109c, 109d) being configured such that, at any time during the transition from its closed state to its open state, any point of said at least one safety element (109a, 109b, 109c, 109d) is arranged at a level:, • located between a first level (L1) defined by the bottom (106) of the body (105) and a second level (L2) defined by a vertex of the distal connecting organ (114) of the bottom (106) of the body (105); • at a distance from the second level (L2).

2. Cylindrical battery cell (100) according to claim 1, wherein the cover (108) comprises a plate (113) mounted hermetically at its periphery at the opening (107), the plate (113) comprising said at least one safety device (109a, 109b, 109c, 109d).

3. Cylindrical battery cell (100) according to claim 2, wherein the plate (113) is welded to the opening (107) such that the first pole (101) comprises the plate (113), said plate (113) being of one piece.

4. Cylindrical battery cell (100) according to any one of claims 2 to 3, wherein said connecting member (114) is: • formed by a portion, in particular the central portion, of the plate (113), said plate (113) constituting the cover (108); or • mounted through a through hole (115) formed in the plate (113), the cover (108) comprising an electrically insulating member (116) interposed between the plate (113) and the connecting member (114), the second pole (102) comprising the connecting member (114).

5. Cylindrical battery cell (100) according to any one of claims 1 to 4, wherein the preferential break zone (111) of said at least one safety element (109a, 109b, 109c, 109d) is formed by a localized thinning of the cover (108).

6. Cylindrical battery cell (100) according to any one of claims 1 to 5, wherein said at least one safety device (109a, 109b, 109c, 109d) comprises, in its closed state, a preferential deformation zone (112) connecting the two opposite longitudinal ends (111b, 111c) of said continuous line (111a).

7. Cylindrical battery cell (100) according to claim 4, wherein said line (111a) continues: • comprises two segments (117a, 117b) forming an angle with each other and connected by a curved portion (117c) of said continuous line (111a), said curved portion (117) being proximal to the connecting organ (114); or • comprises a segment (118) comprising first and second longitudinal ends (118a, 118b) opposite each other, the first longitudinal end (118a) of segment (118) being proximal to the connecting organ (114), and a curved portion (119) extending continuously from the second longitudinal end (118b) of segment (118); or • is at least mostly curved, for example in the manner of an arc of a circle.

8. Cylindrical battery cell (100) according to any one of claims 1 to 7, wherein the cover (108) comprises several safety devices (109a, 109b, 109c, 109d).

9. Cylindrical battery cell (100) according to claim 8 and claim 4, wherein the preferential failure zones (111) have the same shape and are distributed at regular intervals around the connecting member (114).

10. Cylindrical battery cell (100) according to any one of claims 1 to 9, wherein the preferential failure zone (111) is in the form of a groove such that: • the groove depth is between 70% and 95% of the lid thickness (108) at the periphery of the groove; and / or • the longitudinal ends of the preferential breaking zone (111) are separated by a distance greater than or equal to ten times the thickness of the cover (108) at the periphery of the groove; and / or • the length of the groove is between 10% and 60% of the perimeter of the lid (108).

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