Roll-on battery cell comprising cell electrodes and held in a cell housing

Abstract

A battery cell (100) comprises a housing (105) and a roller (102) housed in the housing (105), the roller (102) delimiting a central volume (106) around which said roller (102) is formed by winding. The roller (102) comprises electrodes (103, 104) of the cell (100). The cell (100) comprises at least one return member (101) arranged at least partly in the central volume (106), said at least one return member (101) exerting a return force on the roller (102) tending to ensure that the roller (102) is held between said at least one return member (101) and a wall (107) of the housing (105) of the cell (100). Figure to be published with the abstract: Fig. 3

Description

Title of the invention: Roll battery cell comprising cell electrodes and held in a cell housing Technical field of the invention

[0001] The technical field of the invention relates to battery cells, in particular for a vehicle comprising an electric motor to be powered by a battery comprising cells according to the present invention.

[0002] More particularly, the present invention relates to a battery cell, said cell comprising a housing and a roller housed in the housing, the roller delimiting a central volume around which the roller is formed by winding, the roller comprising electrodes of the cell. State of the prior art

[0003] Known in the state of the art are roll-type battery cells comprising cell electrodes, also known as "jelly roll" in English.

[0004] Conventionally, the roll of a battery cell may be formed by winding a multilayer successively comprising a first electrode sheet, a first separator sheet, a second electrode sheet and a second separator sheet. This roll may be formed by winding the multilayer onto a rotating winding mandrel. After forming the roll, the winding mandrel is separated from the roll, leaving an empty central volume in the center of said roll. The roll is then inserted into a rigid housing and the central volume is either left empty of solid material, or a rigid body, therefore with fixed dimensions and for example tubular, is inserted inside the central volume. The cell further comprises an electrolyte present in the housing.

[0005] The manufacture of such a cell requires great industrial precision in the sense that the housing volume in the casing to receive the roller must be suitably sized to allow the insertion of the roller into the casing and limit the movements of the roller in the casing to avoid the collapse of said roller, in particular when its central volume is left empty of solid material. "Collapse" means that the multilayer breaks down inside the casing, which may cause misalignment of the electrodes (including the aforementioned first and second electrode sheets) and the separator (including the aforementioned first separator sheet and / or second separator sheet). In other words, the multilayer unfolds from the inside, into the central volume. Although current cells when properly sized and pa rameterized are generally satisfactory, they remain perfectible. Indeed, changes in dimensions and / or parameters of the electrodes modify the charging / discharging behavior of the cells. Successive charging and discharging cycles of the cell cause movements of the roller in the case. Naturally, the central volume can vary accordingly, sometimes causing the collapse of the roller in said central volume. The collapse of the roller affects the performance of the cell. In the worst scenarios, the collapse of the roller can lead to dramatic accidents, such as explosions or fires, in particular due to short circuits caused by direct contact of electrodes with opposite potentials (in particular contact of the first and second electrode sheets) due to misalignment of the sheets (i.e.the first electrode sheet, the first separator sheet, the second electrode sheet and the second separator sheet) of the multilayer.

[0006] Thus, there is a need to improve the cell to improve the retention of the roller in the housing, in particular with a view to limiting the occurrence of an accident such as mentioned above. Subject of the invention

[0007] The present invention aims to improve the retention of the roller in the housing.

[0008] For this purpose, the invention relates to a battery cell, said cell comprising a housing and a roller housed in the housing, the roller delimiting a central volume around which said roller is formed by winding, the roller comprising electrodes of the cell, the cell comprising at least one return member arranged at least partly in the central volume, said at least one return member exerting a return force on the roller tending to ensure that the roller is held between said at least one return member and a wall of the housing of the cell.

[0009] This makes it possible to avoid displacements / movements of the roller within the cell which could lead to a collapse of the roller as mentioned in the prior art section or to the creation of short circuit(s) within the cell.

[0010] The cell may further comprise one or more of the following features.

[0011] According to a characteristic of the cell, the roller is held by com pressure of the roller between said at least one return member and the wall of the housing.

[0012] This compression makes it possible to obtain friction forces adapted to maintaining the roller in the housing and makes it possible to tend to effectively avoid the collapse of the roller by taking into account the variation, over time, of the central volume and the natural movements of the roller.

[0013] According to a characteristic of the cell, said at least one return member is configured so as to allow a variation of the volume occupied by the roller around the volume central.

[0014] This makes it possible to absorb expansions inside the cell while maintaining the roller in the housing.

[0015] According to a characteristic of the cell, the cell comprises a plurality of return members distributed in the central volume along an axis of the roller.

[0016] This makes it possible to benefit from the advantage of the presence of the return force while making it possible to reduce the overall weight of the cell since there can then be specific areas of the central volume without a return member. The reduction in the weight of the cell induces a reduction in the weight of the battery which in turn induces, where appropriate, a reduction in the consumption of the vehicle incorporating the battery and set in motion using the battery.

[0017] According to a characteristic of the cell, the return members are arranged so as to occupy within the central volume at least 70% of the height of the roller.

[0018] This ensures suitable support for the roller while limiting the mass added to the cell to limit its weight.

[0019] According to a characteristic of the cell, said at least one return member is elongated and extends in the central volume from a first longitudinal end of the roller to a second longitudinal end of the roller, opposite the first longitudinal end of the roller, so as to exert its return force over its entire length.

[0020] This makes it possible to ensure a uniform distribution of the roll support, in particular over the height of the cell taken in the direction of the roll winding axis.

[0021] According to a characteristic of the cell, said at least one return member is a spring.

[0022] This has the advantage of being simple to implement while having a low unit cost.

[0023] According to a characteristic of the cell, the spring is a torsion spring in the form of an element wound on itself and configured so as to produce a radial force making it possible to urge the roller towards the wall.

[0024] Such an embodiment of the spring is easy to implement and the wound element will tend to naturally open / unwind which induces the radial force.

[0025] According to a characteristic of the cell, the spring is a helical spring.

[0026] The coils of such a spring advantageously make it possible to provide the desired return force.

[0027] According to a characteristic of the cell, said at least one return member is made of steel.

[0028] The steel is suitable to provide the desired function while being compatible for being in the cell.

[0029] According to a characteristic of the cell, said at least one return member is an elastic body or a foam.

[0030] These are two alternatives to a spring that can be adapted as a return member. The elastic body or the foam have the advantage of being inexpensive and, if necessary, allow for less risk of short circuiting because they can be electrically insulating.

[0031] According to a characteristic of the cell, the return force of said at least one return member is substantially radial to the winding axis of the roller and oriented towards the wall of the housing.

[0032] This prevents the roll from collapsing into the central volume.

[0033] According to a characteristic of the cell, the return force of said at least one return member is omnidirectional around the winding axis of the roll and oriented towards the wall of the housing.

[0034] This improves the support to prevent the roll from collapsing into the central volume.

[0035] The invention also relates to a method of manufacturing the battery cell, in particular as described above, the method comprising the following steps: a) providing the housing; b) provide the roller; c) insert the roll into the case; d) inserting said at least one return member into the central volume.

[0036] This allows the cell to be manufactured simply while ensuring adequate support for the roller.

[0037] The manufacturing method may further comprise one or more of the following features.

[0038] According to a characteristic of the manufacturing method, step d) is such that said at least one return member is inserted compressed.

[0039] The compression of said at least one return member allows it to be inserted into the central volume quickly without damaging the roller.

[0040] According to a characteristic of the manufacturing method, said at least one compressed return member has lateral dimensions, measured orthogonally to its direction of insertion into the central volume, strictly less than the lateral dimensions of the central volume measured orthogonally to the direction of insertion of said at least one compressed return member into the central volume.

[0041] This allows simple and secure insertion of said at least one return member into the central volume.

[0042] Other advantages and characteristics may emerge from the detailed description which follows. Brief description of the drawings

[0043] The invention will be better understood upon reading the detailed description which follows, given solely by way of non-limiting example and made with reference to the appended drawings listed below.

[0044] [Fig-1] [Fig.l] schematically represents a battery cell seen in perspective according to one embodiment of the invention.

[0045] [Fig.2] [Fig.2] schematically represents an embodiment of the cell, for example from [Fig.l], according to a sectional view taken orthogonally to the direction of measurement of the height of the cell.

[0046] [Fig.3] [Fig.3] represents a particular embodiment of the cell, by example of [Fig.l], according to a cross-sectional view showing the presence of a return organ placed in the cell.

[0047] [Fig.4] [Fig.4] represents a particular embodiment of the cell, by example of [Fig.l], according to a cross-sectional view, showing the presence of three return organs placed in the cell.

[0048] [Fig.5] [Fig.5] schematically illustrates, in a sectional view, a multilayer used to form a roll arranged in the cell.

[0049] [Fig.6] [Fig.6] schematically illustrates, in a cross-sectional view, a case used to form the cell, particularly as part of a cell manufacturing process.

[0050] [Fig.7] [Fig.7] schematically illustrates, in a cross-sectional view, the housing in which the roller is arranged during the manufacturing process.

[0051] [Fig.8] [Fig.8] schematically illustrates, in a cross-sectional view, the housing in which the roller and the return member are arranged during the roller manufacturing process.

[0052] [Fig.9] [Fig.9] schematically illustrates, in a cross-sectional view, a particular embodiment of a step of the manufacturing process consisting of inserting the return member into the housing in which the roller is arranged.

[0053] [Fig. 10] [Fig. 10] schematically illustrates, in a cross-sectional view, a particular embodiment of a step of the manufacturing process consisting of adding an electrolyte of the cell into the case.

[0054] [Fig. 11] [Fig. 11] schematically illustrates, in a cross-sectional view, a particular embodiment of a step of the manufacturing process consisting of forming the roller to be inserted into the housing.

[0055] 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

[0056] The present invention relates to a battery cell 100 and proposes integrating at least one return member 101 within the cell 100 in order to participate in maintaining a roll 102 of the cell 100, this roll 102 comprising electrodes 103, 104 of the cell 100. In particular, FIGS. 1 to 4 show such a cell 100 according to two embodiments respectively with one return member 101 ([Fig.3]) and with three return members 101 ([Fig.4]), and [Fig.5] illustrates an example of a portion of a multilayer 111 intended to be wound to form the roll 102.

[0057] In particular, the cell 100 comprises a housing 105 and the roller 102 is housed in the housing 105. The roller 102 delimits a central volume 106 around which said roller 102 is formed by winding. Said at least one return member 101, which the cell 100 comprises, is arranged at least partly in the central volume 106. Said at least one return member 101 exerts a return force on the roller 102 tending to ensure that the roller 102 is held between said at least one return member 101 and a wall 107 of the housing 105 of the cell 100.

[0058] By "central volume 106 around which said roller 102 is formed by winding", it is understood that the roller 102 is a winding, that is to say that it comprises an internal surface 102a delimiting the central volume 106 and an external surface 102b at the periphery of the roller 102 around an axis Al of winding of the roller 102.

[0059] The wall 107 of the housing 105 is, preferably, a side wall closed at a first end, preferably longitudinal, by a bottom 108 of the housing 105, in particular from which the wall 107 of the housing 105 rises, and at a second end, preferably longitudinal, by a cover 109 of the cell 100 so as to delimit a sealed internal volume of the cell 100. Sealing is then ensured between the interior of the cell 100 (i.e. the internal volume) and the exterior of the cell 100.

[0060] The cell 100 may comprise, in the housing 105, an electrolyte 110; this notably allows the exchange of ions between the two electrodes 103, 104 to selectively charge or discharge the cell 100. In particular, the roller 102 is immersed in the electrolyte 110.

[0061] In particular, the electrolyte 110 fills the internal volume, in particular notwithstanding the presence of said at least one return member 101 and of the roller 102.

[0062] Generally speaking, by “said at least one return member 101”, it is understood that the cell 100 may comprise a single one, or several which may have identical or similar characteristics. Thus, in the present detailed description, everything that applies to said at least one return member 101 applies to this return member 101 when it is unique or to each return member 101 when there are several.

[0063] The roller 102 may be of the straight cylinder type (whose section adopts the shape of a circle) or of the prismatic type (whose section adopts the shape of a polygon). In particular, in [Fig.l] the roller 102 is a straight cylinder.

[0064] For example, the roll 102 is formed by winding the multi-layer 111 on itself, as for example illustrated in [Fig.5], successively comprising a first electrode sheet 112 (forming for example the aforementioned electrode 103), a first separator sheet 113, a second electrode sheet 114 (forming for example the aforementioned electrode 104) of opposite polarity to the first electrode sheet 112, and a second separator sheet 115.

[0065] Preferably, in the cell 100, the electrolyte 110 impregnates the first and second separator sheets 113, 115.

[0066] The cell 100 with roller 102 is, in particular, called in the technical field of the invention “jelly roll”.

[0067] With respect to the winding axis A1 shown in Figures 3 and 4, the roller 102 can form, radially with respect to the winding axis A1, a millefeuille of which each layer corresponds to a part of the multilayer 111 mentioned above, said parts being in contact so as to tend towards the optimization of the energy density within the cell 100. In Figures 3 and 4, a spacing between the parts of the millefeuille is shown schematically to schematize the presence of the electrolyte 110, but in reality there is in fact contact between the layers in such a way that the first and second electrode sheets 112, 113 are always separated by one of the first and second separator sheets 113, 115 in order to avoid short circuits.

[0068] The housing 105 is notably rigid.

[0069] According to an embodiment allowing: • to obtain friction forces adapted to maintaining the roller 102 in the housing 105; and • to prevent the central volume 106 which can vary over time depending on the variation in the volume of the roller 102 and / or natural movements of the roller 102 from causing the roller to collapse; the maintenance of the roller 102 is preferably ensured by compression of the roller 102 between said at least one return member 101 and the wall 107 of the housing 105.

[0070] In fact, the rigidity of the housing 105 is such that it does not deform in contact with the roller 102 and exerts a reaction force against the roller 102 in particular on its external surface 102b. This reaction force is opposed, where appropriate locally, to the return force of said at least one return member 101, from which it follows that the compression of the roller 102 is ensured using said at least one return member 101 which pushes the roller 102, in particular at its internal surface 102a, against the wall 107 of the housing 105.

[0071] For example, this compression is obtained by the return force of said at least one return member 101 which allows a stress on the roller 102 according to the arrows F1 of FIGS. 3 and 4 in the direction of the housing 105, and more particularly in the direction of its wall 107. The arrows F1 are shown schematically in number two per return member 101 in FIGS. 3 and 4 and are oriented, for the section shown, in opposite directions towards portions of the wall 107 facing each other.

[0072] For example, said at least one return member 101 is configured so as to allow a variation in the volume occupied by the roller 102 around the central volume 106. Thus, the expansions of the roller 102 during the life of the cell 100 are not to the detriment of the maintenance of the roller 102, thus improving safety during use of the cell 100. The central volume 106 can also vary as a function of the variation in the volume occupied by the roller 102.

[0073] Generally, the roller 102 may comprise a first longitudinal end 116 and a second longitudinal end 117 opposite the first longitudinal end 116 of the roller 102.

[0074] According to one embodiment, the cell 100 comprises a plurality of return members 101 distributed in the central volume 106 along an axis of the roller 102. In particular, this axis of the roller 102 is in fact its longitudinal axis and may correspond to the winding axis A1. This embodiment is notably visible in [Fig. 4] which represents by way of example three return members 101 distributed along the axis of the roller which coincides in the example illustrated with the winding axis A1. Each return member 101 then participates in the pressing of the roller 102 at its circumference, i.e. at its external surface 102b facing the wall 107, against the wall 107

[0075] Preferably, the return members 101 are arranged so as to occupy within the central volume at least 70% of the height of the roller 102. The height of the roller 102 is in particular measured along the axis of the roller mentioned above. Thus, the height of the roller 102 corresponds to the distance separating the first longitudinal end 116 and a second longitudinal end 117.

[0076] In particular, each return member 101 is distant from each of the other return members 101, in other words the return members 101 do not cover the entire height of the roller 102.

[0077] According to one embodiment, such as for example illustrated in [Fig. 3], said at least one return member 101 is elongated and extends in the central volume 106 from the first longitudinal end 116 of the roller 102 to the second longitudinal end 117 of the roller 102 so as to exert its return force over its entire length, in particular radially in the direction of the wall 107. For example, ... at least one return member 101 exerts its return force over its entire length in order to press the roller 102 at its circumference, i.e. at its external surface 102b facing the wall 107, against the wall 107. In other words, the return force of said at least one return member 101 is exerted transversely, and preferably radially, to the longitudinal direction of the roller 102.

[0078] According to an exemplary embodiment, and in particular as illustrated in [Fig.3], the cell 100 comprises a single return member 101.

[0079] In [Fig. 3], said at least one return member 101 is arranged entirely in the central volume 106, but it can just as easily protrude from the roller 102 from its first and second longitudinal ends 116, 117 if the configuration of the cell 100 allows it.

[0080] In [Fig. 3], by way of example, the first longitudinal end 116 of the roller 102 is proximal to, and in particular in contact with, the cover 109 and distal to the bottom 108; while the second longitudinal end 117 is distal to the cover 109 and proximal to, and in particular in contact with, the bottom 108.

[0081] Said at least one return member 101 may be a spring.

[0082] The spring may be a torsion spring, for example in the form of an element wound on itself and configured so as to produce a radial force making it possible to urge the roller 102 towards the wall 107. The wound element may be a metal sheet or a metal ribbon. The tendency of the wound element to want to open or unwind will make it possible to exert the return force corresponding to the aforementioned radial force.

[0083] The torsion spring may be a spiral torsion spring.

[0084] The spring, and therefore said at least one return member 101, may be a helical spring. licorice. In this case, the helical spring is advantageously arranged in the central volume 106 so that its direction of elongation, around which its turns are formed, is substantially parallel to the axis A1 of winding of the roller 102. The helical spring thus positioned in the central volume 106 undergoes stresses in the sense that all or part of its turns are compressed transversely to its direction of elongation so as to thus ensure the return force radially relative to its direction of elongation making it possible to maintain the roller 102 between the helical spring and the wall 107 of the housing 105. In fact, the radial compression of the helical spring will tend to modify its length and the properties of the helical spring will induce stresses within it tending to its return to the free length from which results the generation of the return force then radial against the internal surface 102b of the roller 102.The coil spring can be compression.

[0085] By “substantially parallel to the winding axis A1 of the roller 102”, it is understood parallel or parallel to plus or minus 10 degrees.

[0086] The helical spring may be a steel wire, in particular stainless steel. The steel wire is then shaped in a suitable manner to form the turns around the direction of elongation of the helical spring.

[0087] Said at least one return member 101 may be made of steel.

[0088] Said at least one return member 101 may be a foam.

[0089] Said at least one return member 101 may be a plastic return element.

[0090] Said at least one return member 101 may be an elastic body. In this case the elastic body may be an elastic material which has the property of tending to undergo expansion when it has undergone compression in order to exert the return force on the roller 102.

[0091] Preferably, the return force of said at least one return member 101 is substantially radial to the winding axis A1 of the roller 102 and oriented towards the wall 107 of the housing 105. For example, this orientation is shown diagrammatically by the arrows F1 in FIGS. 3 and 4. This is made possible in particular in the context of the embodiment where the spring is a torsion spring or a helical spring as described above.

[0092] By "substantially radial" is meant perpendicular, or orthogonal, to the winding axis Al, or perpendicular, or orthogonal, to the winding axis Al of the roller 102 at plus or minus 10 degrees.

[0093] The return force of said at least one return member 101 may be omnidirectional, in particular around the winding axis A1 of the roller 102 and oriented towards the wall 107 of the housing 105. For example, this makes it possible to ensure a preferably homogeneous application of the roller 102 over at least one surface portion, for example of revolution or adopting the form of a closed loop of polygonal section, in particular orthogonal to the winding axis A1, of the wall 107.

[0094] The invention also relates to a method for manufacturing the battery cell 100. This method comprises the following steps: a) provide the housing 105, for example as shown in [Fig.6]; b) providing the roller 102 comprising the electrodes 103, 104 of the cell 100; c) inserting the roller 102 into the housing 105, [Fig.7] shows as an example the result of step c); d) inserting said at least one return member 101 into the central volume 106 (for example as shown in figures 8 and 9). These steps have the advantage of being easy to implement and the addition of said at least one return member 101 ultimately makes it possible to obtain adequate support for the roller 102 in the housing 105.

[0095] Of course, the method may comprise a step e) of adding the electrolyte 110 into the housing 105, in particular after steps c) and d), so as to add only the required quantity of electrolyte 110 into the housing 105, for example by filling the housing. This step e) is notably illustrated in [Fig. 10] showing the housing 105 in which the electrolyte 110 and the roller 102 surrounding said at least one return member 101 are arranged.

[0096] The method may further comprise a step f) of sealing the housing 105. Step f) may consist of placing the cover 109 on the housing 105 and crimping it to the housing 105 (Figures 1, 3 and 4).

[0097] Step f) is notably implemented in order to form a container (housing 105 plus cover 109) sealed against the electrolyte 110 to prevent leaks of electrolyte 110 from the container to the outside of the container.

[0098] The manufacturing method may be such that the roll 102 provided in step b) is secured to a winding mandrel 119 used to form the roll 102 (see in particular in this regard [Fig.l 1], and that the winding mandrel 119 is removed before step c), in particular this removal corresponds to a separation of the winding mandrel 119 from the roll 102 and to an extraction of the winding mandrel 119 before inserting the roll 102 into the housing 105.

[0099] Thus, the multilayer 111 as shown in [Fig.5] can be wound onto the winding mandrel 119 prior to step b) in order to form the roll 102 which will be inserted into the housing in step c) after removal of the winding mandrel 119 relative to the roll 102. The removal of the winding mandrel 119 allows the central volume 106 to be left free of access in order to insert therein, after having inserted the roll 102 into the housing 105, said at least one return member 101 (step d)).

[0100] Preferably, step d) is such that said at least one return member 101 is inserted compressed. This compression advantageously allows said at least one return member 101 to have a lateral dimensioning adapted to its insertion into the central volume 106 without damaging the roller 102, for example without generating friction against the internal surface 102a of the roller 102 delimiting the central volume 106. This is notably visible in [Fig.9].

[0101] Preferably, the compression of said at least one return member 101, so that it is inserted into the housing 105, is such that it has dimensions allowing its insertion into the central volume 106 without touching the roller 102. For this, said at least one compressed return member 101 may have lateral dimensions, measured orthogonally to its direction of insertion into the central volume 106, strictly less than the lateral dimensions of the central volume 106 measured orthogonally to the direction of insertion of said at least one compressed return member 101 into the central volume 106.

[0102] Then, after insertion of said at least one compressed return member 101 into the central volume 106, its compression can be released to allow its expansion into the central volume 106, resulting in the roller 102 being held in place by the force of recall exerted by said at least one return member 101 on the roller 102.

[0103] By "expansion of said at least one return member 101", is meant in the present description an expansion of the volume occupied by the latter. For example, an expansion of the foam corresponds to an increase in its volume, an expansion of the torsion spring, or where appropriate of the helical spring, allows an increase in its diameter to ensure the aforementioned radial force.

[0104] For example, as shown in [Fig.9], step d) can be implemented using a gripping member such as a clamp 300. This gripping member, in addition to serving as a gripper for said at least one return member 101, makes it possible, where appropriate, to keep said at least one return member 101 compressed by opposing its return force.

[0105] When said at least one return member 101 is compressed by the gripping member, the separation of the gripping member from said at least one return member 101, then in place in the central volume 106, allows said at least one return member 101 to come into contact with the roller 102 in the central volume 106 ([Fig.8]) where it then exerts its return force.

[0106] The cell 100 finds an industrial application in the field of batteries, particularly for vehicles, a battery comprising a plurality of cells 100 as described.

[0107] The battery is preferably a battery for a motor vehicle and intended to serve as an energy source for an electric motor of the motor vehicle making it possible to implement movement of the motor vehicle, for example by propulsion or traction via two drive wheels of the vehicle, or by all-wheel drive via four drive wheels in particular when two electric motors, 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 wheels of the motor vehicle.

Claims

Claims

1. Battery cell (100), said cell (100) comprising a housing (105) and a roller (102) housed in the housing (105), the roller (102) delimiting a central volume (106) around which said roller (102) is formed by winding, the roller (102) comprising electrodes (103, 104) of the cell (100), characterized in that the cell (100) comprises at least one return member (101) arranged at least partly in the central volume (106), said at least one return member (101) exerting a return force on the roller (102) tending to ensure that the roller (102) is held between said at least one return member (101) and a wall (107) of the housing (105) of the cell (100).

2. Cell (100) according to claim 1, in which the roller (102) is held in place by compressing the roller (102) between said at least one return member (101) and the wall (107) of the housing (105).

3. Cell (100) according to any one of claims 1 to 2, in which said at least one return member (101) is configured so as to allow a variation in the volume occupied by the roller (102) around the central volume (106).

4. Cell (100) according to any one of claims 1 to 3, comprising a plurality of return members (101) distributed in the central volume (106) along an axis of the roller (102).

5. Cell (100) according to claim 4, in which the return members (101) are arranged so as to occupy within the central volume at least 70% of the height of the roller (102).

6. Cell (100) according to any one of claims 1 to 3, in which said at least one return member (101) is elongated and extends in the central volume (106) from a first longitudinal end (116) of the roller (102) to a second longitudinal end (117) of the roller (102), opposite the first longitudinal end (116) of the roller (102), so as to exert its return force over its entire length.

7. Cell (100) according to any one of claims 1 to 6, in which said at least one return member (101) is a spring.

8. Cell (100) according to claim 7, in which the spring is a torsion spring in the form of an element wound on itself and configured so as to produce a radial force making it possible to urge the roller (102) towards the wall (107).

9. The cell (100) of claim 7, wherein the spring is a helical spring.

10. Cell (100) according to any one of claims 7 to 9, wherein said at least one return member (101) is made of steel.

11. Cell (100) according to any one of claims 1 to 6, wherein said at least one return member (101) is an elastic body or a foam.

12. Cell (100) according to any one of claims 1 to 11, in which the return force of said at least one return member (101) is substantially radial to the winding axis of the roll (102) and oriented towards the wall (107) of the housing (105).

13. Cell (100) according to any one of claims 1 to 12, in which the return force is omnidirectional around the axis (Al) of winding of the roll (102) and oriented towards the wall (107) of the housing (105).

14. A method of manufacturing a battery cell (100) according to any one of claims 1 to 13, comprising the following steps: a) providing the housing (105); b) providing the roller (102); c) inserting the roller (102) into the housing (105); d) inserting said at least one return member (101) into the central volume (106).

15. Manufacturing method according to claim 14, wherein step d) is such that said at least one return member (101) is inserted compressed.

16. Manufacturing method according to claim 15, wherein said at least one compressed return member (101) has lateral dimensions, measured orthogonally to its direction of insertion into the central volume (106), strictly less than the lateral dimensions of the central volume (106) measured orthogonally to the direction of insertion of said at least one compressed return member (101) into the central volume (106).

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