Current collector, prismatic battery cell and associated manufacturing method

Abstract

The invention relates to a primary current collector (10) for a prismatic electric battery cell (1) comprising at least two lateral arms (21), each lateral arm (21) comprising a foldable stop (25) forming a stop surface (s25) against which a current collection tab (55) is intended to bear. The invention also relates to an assembly (7) and a prismatic battery cell (1) comprising such a primary current collector (10). The invention also relates to a method of manufacturing a battery cell (1).

Description

[0001] DESCRIPTION

[0002] TITLE: Current collector, prismatic battery cell and associated manufacturing process

[0003] Technical field of the invention

[0004] The present invention relates to the field of prismatic electric battery cells.

[0005] More particularly, the invention relates to a current collector for such a prismatic battery cell, as well as an assembly comprising a cover and such a current collector.

[0006] State of the art

[0007] In the field of secondary batteries, and particularly batteries for electric vehicles, prismatic battery cells are commonly manufactured. Their shape allows them to be easily stacked side by side, which is especially advantageous for building an electric vehicle battery. Generally, such battery cells consist of two electrodes: an anode and a cathode, which are in the form of sheets. These electrodes are then stacked and compressed to form one or more electrode stacks that make up the prismatic battery cell. Between the anode and the cathode, a separator is positioned to prevent a short circuit between the two electrodes. The electrode stack is then inserted into a casing that serves to protect the stack and to allow the insertion of an electrolyte, which facilitates ion transport between the two electrodes.

[0008] To maximize battery cell capacity, it is known to create two stacks of electrodes designed to be inserted inside the same battery cell casing. Furthermore, the prismatic battery cell cover includes two terminals used for interconnection with other battery cells.

[0009] To channel the current produced by the electrode stacks to the terminals of the cover, it is known in the prior art to use a current collector for each terminal. These current collectors are electrically connected to each electrode. They must ensure efficient and reliable collection of the current produced by the electrodes. Furthermore, once the current collection is achieved, it is necessary to ensure that the assembly formed by the electrodes and current collectors is securely fixed inside the casing to limit any movement of the stack relative to the casing under normal battery operating conditions. Thus, to have a prismatic battery cell operating under optimal conditions, precise positioning of the stacks relative to the current collectors on one hand, and to the casing on the other, is necessary.This positioning is a critical step in the manufacturing process, particularly for large-scale production.

[0010] It is indeed necessary to ensure that the electrode stacks are inserted into the battery cell casing without coming into contact with the casing walls, as this could damage them. Furthermore, once inserted, the stacks must not be too close to the battery cell cover, as this would prevent the electrolyte from being introduced at the desired flow rate. Therefore, improper positioning of the stacks within the battery cell casing can lead to the disposal of numerous battery cells.

[0011] There is therefore a need to find a prismatic battery cell in which the current is efficiently collected at the electrodes and routed to the cover, and in which the positioning of the electrode stacks in the casing is reliable and simply achieved.

[0012] Object of the invention

[0013] The present invention aims to provide a solution that addresses all or part of the aforementioned problems.

[0014] This goal can be achieved through the implementation of a primary current collector for a prismatic electric battery cell comprising: an upper part intended to be electrically connected to a terminal of the battery cell; and a lateral part, forming at a non-zero angle with the upper part and intended to be electrically connected to current collection tabs of an electrode of the battery cell, the lateral part comprising at least two lateral arms comprising a proximal end portion fixed to the upper part, and a free distal end portion; each lateral arm comprising: o a main body extending in a laterally direction and intended to come into electrical contact with a current collection tab;and a foldable stop forming the free distal end portion of said lateral arm, said foldable stop being folded around a folding axis substantially perpendicular to the lateral direction, so as to form a stop surface at which said current collection tab is intended to bear.

[0015] The previously described design allows for the creation of a primary current collector for prismatic battery cells in which each lateral arm is capable of acting as a stop for one of the current collection tabs of the battery cell electrode. This facilitates the lateral positioning of the electrode stack within the prismatic battery cell casing. Furthermore, the single stop at the distal end of each lateral arm reduces the number of folds in the current collector, simplifying the manufacturing of the lateral arms. This also mitigates the potential fragility of the lateral arms, which can be more pronounced at the folds.

[0016] In other words, the folding stops allow for pre-positioning of the battery cell electrodes with the current collectors. This facilitates their placement in the battery cell casing before attaching the current collection tabs to the primary current collector. This ensures that the insertion into the casing is carried out smoothly and without risk of contact between the electrodes and the casing. Furthermore, the electrodes inserted into the casing are not too close to the lid, allowing for the electrolyte to be filled at an appropriate rate.

[0017] The primary current collector may also have one or more of the following characteristics, taken alone or in combination.

[0018] According to one embodiment, the folding stop is able to be folded around the folding axis to pinch the current collection tab.

[0019] Thus, pinching the current collection tabs between the main body and the folding stop keeps the current collection tabs in contact with the primary current collector, which facilitates welding operations.

[0020] According to one embodiment, for each lateral arm, a thickness of the main body is strictly greater than a thickness of the folding stop.

[0021] Thus, it is possible to facilitate the folding of the bendable stop during the manufacture of the primary current collector, to form the stop surface.

[0022] According to one embodiment, at least one of the lateral arms includes a notch formed at the proximal end portion.

[0023] In this way, a preferred folding zone for the side arm can be provided at the notch. This notch facilitates folding of the side section relative to the upper section. In one embodiment, the folding stops of the two side arms are folded outwards so that the distal ends of the two side arms move away from each other.

[0024] In this way, it is possible to more easily position the current collection tabs on the stop surfaces, while also facilitating the folding of the foldable stops against said current collection tabs.

[0025] According to one embodiment, for each lateral arm, the folding stop forms an angle with the main body less than or equal to 90°.

[0026] Thus, the foldable stop forms a guide for positioning the current collection tab, which allows this current collection tab to be positioned before any welding operation or before its insertion into the battery cell housing.

[0027] The object of the invention can also be achieved through the implementation of an assembly for a prismatic electric battery cell comprising: a cover including a first terminal and a second terminal of opposite polarity to the first terminal; a primary current collector electrically connected on one side to the first terminal and intended on the other side to be electrically connected to first electrodes; and a secondary current collector electrically connected on one side to the second terminal and intended on the other side to be electrically connected to second electrodes distinct from the first electrodes; an assembly in which the primary current collector is a primary current collector as described above.

[0028] The arrangements described above make it possible to propose an assembly for prismatic battery cells configured both to collect the current from the battery cell, to ensure a watertight seal of the battery cell casing by the cover, and to efficiently position the electrode assembly relative to the cover, and therefore relative to the battery cell casing.

[0029] According to an embodiment in which the secondary current collector comprises:

[0030] -an upper section electrically connected to the second terminal of the cover; and a lateral section, forming a non-zero angle with the upper section and intended to be electrically connected to current collection tabs of the second electrodes of the battery cell, the lateral section comprising at least two lateral tabs each extending in the lateral direction between a proximal end fixed to the upper section, and a free distal end; each lateral tab having a contact surface intended to come into electrical contact with one of the current collection tabs of the second electrodes, each lateral tab further comprising a folding blade folded around an axis substantially parallel to the lateral direction.

[0031] In this way, the secondary current collector is configured to allow precise positioning of the current collection tabs of the second electrodes relative to the cover. This makes it possible to form a rigid grouping of elements intended to be inserted into the prismatic battery cell casing.

[0032] The object of the invention can also be achieved through the implementation of a prismatic battery cell for an electric propulsion vehicle, said battery cell comprising: a casing having a prismatic shape, the casing having a top opening and internally delimiting a housing; at least two electrode assemblies arranged in the housing where each assembly comprises the successive assembly of first and second electrodes of opposite polarity and separated from each other by a porous separator film; the first electrodes each having a current-collecting tab projecting from the assembly and being configured to collect an electric current from said first electrode;an assembly as described above, wherein the cover provides a tight seal for the upper opening of the housing, wherein the secondary current collector is electrically connected to the second electrodes, and wherein the lateral arms of the primary current collector are respectively in electrical contact with one of the current-collecting tabs of the first electrodes, the folding stops being folded around the current-collecting tabs of the first electrodes so that each current-collecting tab is pinched between the main body and the folding stop of the corresponding lateral arm.

[0033] The previously described provisions make it possible to propose a battery cell in which the grouping formed by the cover and the assembly facilitates its positioning in the housing defined by the casing.

[0034] Indeed, the stop surface of each folding stop prevents the current collection tab from moving in the direction of insertion of the corresponding electrode assembly into the housing. Thus, the two lateral arms allow for precise positioning of the electrode assembly according to its insertion direction into the housing.

[0035] The battery cell may also exhibit one or more of the following characteristics, taken alone or in combination.

[0036] In one embodiment, the first separator and / or the second separator are porous. Thus, they are adapted to allow the passage of the electrolyte, and therefore the ions it contains, through said separator.

[0037] According to one embodiment: the housing has a housing width measured along a transverse direction defined perpendicular to the bending axis and the lateral direction; wherein the two electrode assemblies each have an assembly thickness measured along the transverse direction; and wherein the two lateral arms are separated from each other by a positioning distance, said positioning distance being strictly greater than the sum of halves of said assembly thicknesses, and being strictly less than the difference between the housing width and the sum of halves of said assembly thicknesses.

[0038] Thus, the positioning distance between the two lateral arms allows the position of the electrode assemblies to be fixed simply in relation to the housing of the casing.

[0039] In other words

[0040] According to one embodiment, the lateral arms have an arm length measured along the lateral direction, said arm length being less than one third of a length of the housing length, measured along the lateral direction.

[0041] Thus, the arm length of the side arms allows the position of the electrode assemblies to be fixed vertically relative to the cover.

[0042] According to one embodiment, each current collection tab and each main body has a width measured along an axis parallel or coincident with the folding axis, a width of a main body being substantially equal to a width of the current collection tab with which said main body is in electrical contact.

[0043] Thus, it is possible to ensure optimal current transfer between the current collection tab and the corresponding lateral arm.

[0044] By "approximately equal", we mean "equal to within 10%".

[0045] According to one embodiment, the primary current collector and the current collection tabs of the first electrodes are formed of the same material. Thus, the electrical connection between the primary current collector and the current collection tabs is improved.

[0046] According to one embodiment, the material of the primary current collector and the current collection tabs of the first electrodes comprises aluminum.

[0047] Advantageously, aluminum is a material that is easier to bend, so it is possible to facilitate the bending of the folding stops while maintaining a good electrical connection between the primary current collector and the current collection tabs.

[0048] In general, the cathode of a battery cell comprises an aluminum foil, so the provisions described above apply preferentially to the cathode.

[0049] According to one embodiment, the main body of each lateral arm is welded to the current collection tab with which said main body is in electrical contact.

[0050] In this way, it is possible to keep the electrode assembly securely attached to the primary current collector, which ensures good stability of the electrode assembly in the battery cell casing, especially when it is in operation.

[0051] According to one embodiment, the second electrodes each have a current-collecting tab projecting from the assembly and configured to collect an electric current from said second electrode, each folding blade of the side tabs of the secondary current collector being folded over one of the current-collecting tabs of the second electrodes.

[0052] In this way, the side tabs are configured to block translation in both directions of the corresponding current collection tabs, in a direction perpendicular to the lateral direction.

[0053] The object of the invention can also be achieved through the implementation of a method for manufacturing a battery cell, the method comprising the following steps: a preliminary positioning step, in which the current-collecting tabs of the first electrodes bear respectively on one and the other of the stop surfaces of the foldable stops of the primary current collector; a first connection step, in which for each lateral arm, the foldable stop is folded around the current-collecting tab which is bearing on this foldable stop, so as to place the corresponding main body in electrical contact with this current-collecting tab; a second connection step, in which the secondary current collector is brought into electrical contact with the second electrodes;an introduction step, in which the group formed by the assembly and the electrode assemblies is introduced into the housing of the casing, the cover ensuring a tight seal of the upper opening of the casing.;

[0054] The arrangements described above allow us to propose a manufacturing process for a prismatic battery cell in which the position of the electrode assemblies relative to the cover is controlled by the butting of the current collection tabs, and by the folding of the foldable stops, during the preliminary positioning step, and during the first connection step.

[0055] The manufacturing process may also have one or more of the following characteristics, taken alone or in combination.

[0056] According to one embodiment, the manufacturing process further includes a welding step carried out after the first connection step, in which the main body of each lateral arm of the primary current collector is welded to the current collection tab with which it is in electrical contact.

[0057] Advantageously, the first connection step allows the main body of each side arm to be kept in contact with one of the current collection tabs, which facilitates the welding step.

[0058] According to one embodiment, the second connection step includes, for each lateral leg of the secondary current collector, the insertion of one of the current collection tabs of the second electrodes between the contact surface and the bending blade.

[0059] Thus, the manufacturing process allows the current collection tabs of the first electrodes to be fixed on the one hand with the primary current collector, thus fixing at least one translation between the assembly and the electrode assemblies, and on the other hand to fix the second electrodes with the secondary current collector, thus fixing at least another translation between the assembly and the electrode assemblies.

[0060] Brief description of the drawings

[0061] Other aspects, objectives, advantages, and features of the invention will become clearer upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0062] Figure 1 is a schematic view of an assembly comprising a primary current collector according to the invention.

[0063] Figure 2 is a schematic view of the assembly shown in Figure 1 when electrically connected to the electrode assemblies. Figure 3 is a schematic view of the assembly shown in Figure 1 and its insertion into the battery cell casing.

[0064] Figure 4 is a schematic view showing the secondary current collector.

[0065] Figure 5 is a schematic view of a sequence of steps in the manufacturing process according to a particular embodiment of the invention.

[0066] Detailed description

[0067] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale to ensure clarity. Moreover, the different embodiments and variants are not mutually exclusive and can be combined.

[0068] As can be seen in Figures 1 to 4, the invention relates to a primary current collector 10 for a prismatic electric battery cell 1. The invention also relates to such a battery cell 1, partially shown in Figure 3.

[0069] As can be seen in this figure, the battery cell 1 comprises a prismatic housing 4. The housing 4 internally delimits a compartment 9 and has a top opening 8 that provides access to this compartment 9. The compartment 9 can extend along a lateral direction denoted "Z," which corresponds to the direction of insertion of electrode assemblies 50 that will be described later. The top opening 8 has a generally rectangular shape in a plane substantially perpendicular to the lateral direction Z. For example, this top opening 8 can be characterized by an opening length (not shown) measured along a longitudinal direction denoted "X," substantially perpendicular to the lateral direction, and by a width, corresponding to a compartment width L9, which is measured along a transverse direction Y defined substantially perpendicular to the longitudinal direction X and the lateral direction Z.

[0070] Such a housing 9 is configured to receive at least two assemblies 50 of electrodes 51, 53. Each assembly 50 comprises the successive assembly of first and second electrodes 51, 53 of opposite polarity and separated from each other by a porous separating film.

[0071] The first electrode 51 may include a first metal foil in the form of a thin strip, onto which a layer of a first active material is deposited. If the first electrode 51 is a cathode, the first metal foil may be aluminum. The second electrode 53 may include a second metal foil in the form of a thin strip, onto which a layer of a second active material is deposited. If the second electrode 53 is an anode, the second metal foil may be copper.

[0072] The insulating separators are arranged so that no electrical contact is possible between the first electrode 51 and the second electrode 53. The insulating separators also have a porous structure, allowing the passage of an electrolyte comprising ions responsible for the charge transfer between the first electrode 51 and the second electrode 53.

[0073] In the particular case of prismatic battery cells 1, the assemblies 50 generally comprise a stacking or winding of the layers previously described, and in particular two stackings or windings, thus forming two distinct assemblies 50 intended to be housed in a single housing 9. Figures 2 to 4 illustrate in particular an embodiment in which the two assemblies 50 of electrodes 51, 53 each have an assembly thickness e50a, e50b measured along the transverse direction Y.

[0074] The first electrodes 51 each have a current-collecting tab 55 projecting from the assembly 50 and configured to collect an electric current from said first electrode 51. In the embodiment shown in Figures 2 and 3, the battery cell 1 comprises two assemblies 50, and therefore two current-collecting tabs 55 connected to the first electrodes 51 of each of the assemblies 50.

[0075] In general, the second electrodes 53 also each have a current-collecting tab 55 projecting from the assembly 50, and configured to collect an electric current from said second electrode 53. In the embodiment shown in Figure 4, the battery cell 1 comprises two assemblies 50, and therefore two current-collecting tabs 55 connected to the second electrodes 53 of each of the assemblies 50. These current-collecting tabs 55 are distinct from those that are electrically connected to the first electrodes 51.

[0076] The battery cell 1 also includes a cover 6 comprising a first terminal 2, visible in figures 1 to 3, and a second terminal 3 of opposite polarity to the first terminal 2, and visible in figure 4. The cover 6 ensures a tight seal of the upper opening 8 of the housing 4.

[0077] Battery cell 1 also includes a primary current collector 10 for electrically connecting the first electrodes 51 to the first terminal 2, and a secondary current collector 30 for electrically connecting the second electrodes 53 to the second terminal 3.

[0078] For example, the primary current collector 10 can be a primary current collector 10 according to the invention, an embodiment of which is shown in Figures 1 to 3. This primary current collector 10 can advantageously be made of the same material as the current collection tabs 55 of the first electrodes 51. Thus, the electrical connection between the primary current collector 10 and the current collection tabs 55 is improved. More specifically, the material of the primary current collector 10 and the current collection tabs 55 of the first electrodes 51 can include aluminum. Advantageously, aluminum is a material that is easier to bend, so it is possible to facilitate the bending of flexible stops 25 (which will be described later) while maintaining a good electrical connection between the primary current collector 10 and the current collection tabs 55.

[0079] In general, the cathode of a battery cell 1 comprises an aluminum foil, so the provisions described above apply preferentially to the cathode.

[0080] The primary current collector 10 includes first of all an upper part 11 intended to be electrically connected to one of the terminals 2, 3 of the battery cell 1, for example the first terminal 2. This upper part 11 can in particular extend in the longitudinal direction X.

[0081] The primary current collector 10 further comprises a lateral portion 20, forming a non-zero angle with the upper portion 11. Generally, the lateral portion 20 forms an angle of approximately 90° with the upper portion 11, so that it extends in the lateral direction Z. This lateral portion 20 is intended to be electrically connected to current collection tabs 55 of the electrodes 51, 53 of the battery cell 1, for example, the first electrodes 51. In other words, the primary current collector 10 is electrically connected on one side to the first terminal 2 and electrically connected on the other side to the first electrodes 51, via the current collection tabs 55.

[0082] As illustrated in Figures 1 to 3, the lateral part 20 comprises at least two lateral arms 21, each including a proximal end portion 21p attached to the upper part 11, and a free distal end portion 21d. The figures illustrate, in particular, an embodiment in which the lateral part 20 comprises two lateral arms 21. The number of lateral arms 21 is generally equal to the number of assemblies 50 present in the battery cell 1, since each lateral arm 21 is electrically connected to one of the assemblies 50 of the battery cell 1 via the current-collecting tabs 55. Furthermore, these lateral arms 21 can be connected to each other at their proximal end portions 21p, thus forming a fork shape.

[0083] It is also possible to provide that at least one of the lateral arms 21 includes a notch 27 provided at the level of the proximal end portion 21p. In this way, it is possible to provide a preferential folding zone of the lateral arm 21, at the level of the notch 27. This notch 27 thus makes it easier to fold the lateral part 20 in relation to the upper part 11.

[0084] Each lateral arm 21 comprises a main body 23 extending along the lateral direction Z and intended to make electrical contact with a current-collecting tab 55. Each current-collecting tab 55 connected to the primary current collector 10 may have a width denoted "L55" measured along the longitudinal direction X. Each main body 23 may have a width denoted "L23" measured along this longitudinal direction X. It may then be advantageous for the width L23 of a main body 23 to be substantially equal to the width L55 of the current-collecting tab 55 with which said main body 23 is in electrical contact. Thus, it is possible to ensure optimal current transfer between the current-collecting tab 55 and the corresponding lateral arm 21. Throughout this text, "substantially equal" means "within 10%" or "within 10°".

[0085] Furthermore, the main bodies 23 of the lateral arms 21 may have an arm length L21 measured along the lateral direction Z, which is less than one third of a length of the housing 9 of the casing 4, measured along the lateral direction Z. Thus, the arm length L21 of the lateral arms 21 allows the position of the electrode assemblies 51, 53 to be fixed vertically relative to the cover 6.

[0086] As will be described later, the gap between the two lateral arms 21 can be used to position the assemblies 50 in the housing 9 of the battery cell 1, or to pre-position the assemblies 50 relative to the cover 6 of the battery cell 1, before the assemblies 50 are inserted into the housing 9. To do this, it is advantageous to provide that the lateral arms 21 are separated from each other by a positioning distance denoted "D" chosen relative to the final positioning of the assemblies 50 in the housing 9. For example, this positioning distance D can be chosen to be strictly greater than the sum of halves of the assembly thicknesses e50a, e50b, and strictly less than the difference between the housing width L9 and the sum of halves of said assembly thicknesses e50a, e50b. In other words (e50 a + e50 fe ) < D < L9 - (e50 a+ e50 fe ). Thus, the positioning distance D between the two lateral arms 21 allows the position of the electrode assemblies 50 51, 53 to be fixed simply in relation to the housing 9 of the casing 4.

[0087] Each lateral arm 21 further comprises a folding stop 25 forming the free distal end portion 21d of said lateral arm 21. Said folding stop 25 is folded about a folding axis X substantially perpendicular to the lateral direction Z, so as to form a stop surface s25 against which said current collection tab 55 is intended to bear. According to the embodiments shown, the folding axis X is parallel to the longitudinal direction X, which is why the same reference dimension is used. For example, the folding stops 25 may have a stop length denoted "L25" and measured along the transverse direction Y that is less than or equal to half of one of the assembly thicknesses e50a, e50b.

[0088] Advantageously, the folding stops 25 of the two lateral arms 21 can be folded outwards so that the distal ends of the two lateral arms 21 move away from each other. In this way, it is easier to position the current collection tabs 55 on the stop surfaces 25, while also facilitating the folding of the folding stops 25 against said current collection tabs 55. For example, the folding stop 25 can form an angle with the main body 23 of 90° or less. Thus, the folding stop 25 forms a guide for positioning the current collection tab 55, which allows this current collection tab 55 to be positioned before any welding operation or before its insertion into the housing 4 of the battery cell 1.

[0089] It is also possible, as illustrated in Figure 3, for the folding stops 25 to be folded around the folding axis X to pinch the current-collecting tab 55. Thus, pinching the current-collecting tabs 55 between the main body 23 and the folding stop 25 maintains contact between the current-collecting tabs 55 and the primary current collector 10, thereby facilitating welding operations. To facilitate folding the folding stop 25 during the manufacture of the primary current collector 10, it is advantageous to ensure that the thickness of the main body 23 is strictly greater than the thickness of the folding stop 25.

[0090] It is therefore clearly understood that the folding stops 25 allow for the preliminary positioning of the electrodes 51 of the battery cell 1 with the primary current collector 10. This facilitates their positioning in the housing 4 of the battery cell 1 before the current collection tabs 55 are attached to the primary current collector 10. This ensures that insertion into the housing 4 will be carried out correctly and smoothly, without risk of contact between the electrodes 51 and the housing 4. Furthermore, the electrodes 51 inserted into the housing 4 are not too close to the cover 6, thus allowing the electrolyte to be filled at an appropriate flow rate.

[0091] The previously described arrangements allow for the design of a primary current collector 10 for a prismatic battery cell 1, in which each lateral arm 21 is capable of forming a stop for one of the current collection tabs 55 of the electrode 51 of the battery cell 1. This facilitates the positioning of the electrode stack 51 along the lateral direction Z within the casing 4 of the prismatic battery cell 1. Furthermore, the formation of a single stop at the distal end of each lateral arm 21 reduces the number of folds in the current collector 10, thus simplifying the manufacturing of the lateral arms 21. This also reduces the potential fragility of the lateral arms 21, which can be greater at the folds.

[0092] The invention also relates to an assembly 7 for a prismatic electric battery cell 1 comprising the cover 6, the primary current collector 10 described above and the secondary current collector 30 which is electrically connected on one side to the second terminal 3 and which is intended on the other side to be electrically connected to the second electrodes 53. An assembly 7 thus formed makes it possible both to collect the current from the battery cell 1, to ensure a watertight seal of the housing 4 of the battery cell 1 by the cover 6, and to efficiently position the electrode assembly 50 with respect to the cover 6, and therefore with respect to the housing 4 of the battery cell 1.

[0093] Although not limiting, it is possible that such an assembly 7 may include a secondary current collector 30 as shown in Figure 4.

[0094] This secondary current collector 30 may include an upper section 31 electrically connected to the second terminal 3 of the cover 6. This upper section 31 may extend along the longitudinal direction X. The secondary current collector 30 may also include a lateral section 40, forming a non-zero angle with the upper section 31. Generally, the lateral section 40 forms an angle of approximately 90° with the upper section 31, so that it extends along the lateral direction Z. This lateral section 40 is intended to be electrically connected to the current collection tabs 55 of the second electrodes 53 of the battery cell 1. In other words, the secondary current collector 30 is electrically connected on one side to the second terminal 3 and electrically connected on the other side to the second electrodes 53.

[0095] The lateral section 40 may include at least two lateral tabs 41, each extending in the lateral direction Z between a proximal end 41p attached to the upper section 31 and a free distal end 41d. Similar to the primary current collector 10, the secondary current collector 30 shown in the figures includes two lateral tabs 41. The number of lateral tabs 41 is generally equal to the number of assemblies 50 present in the battery cell 1, since each lateral tab 41 is electrically connected to one of the assemblies 50 of the battery cell 1 via the current-collecting tabs 55. Furthermore, these lateral tabs 41 may be connected to each other at their proximal ends 41p, thus forming a fork shape.

[0096] Each lateral tab 41 may have a contact surface s41 intended to make electrical contact with one of the current-collecting tabs 55 of the second electrodes 53. Each lateral tab 41 may further include a folding blade 43 folded about an axis substantially parallel to the lateral direction Z. In this way, the secondary current collector 30 is configured to allow precise positioning of the current-collecting tabs 55 of the second electrodes 53 relative to the cover 6. It is thus possible to form a fixed grouping of elements intended to be inserted into the casing 4 of the prismatic battery cell 1.

[0097] The battery cell 1 according to the invention thus comprises the housing 4, at least two assemblies 50 arranged in the housing 9, and an assembly 7 as described above, in which the secondary current collector 30 is electrically connected to the second electrode 53, and in which the folding stops 25 are folded around the current collection tabs 55 of the first electrodes 51 so that each current collection tab 55 is pinched between the main body 23 and the folding stop 25 of the corresponding lateral arm 21.

[0098] Advantageously, the main body 23 of each lateral arm 21 can be welded to the current-collecting tab 55 with which said main body 23 is in electrical contact. In this way, it is possible to keep the electrode assembly 50 51, 53 fixed to the primary current collector 10, which ensures good stability of the electrode assembly 50 51, 53 in the housing 4 of the battery cell 1, particularly when it is in operation.

[0099] Furthermore, each folding blade 43 of the lateral tabs 41 of the secondary current collector 30 can be folded (and optionally welded) over one of the current collection tabs 55 of the second electrodes 53. In this way, the lateral tabs 41 are configured to block translation in both directions of the corresponding current collection tabs 55, in a direction perpendicular to the lateral direction Z, for example the longitudinal direction X and / or the transverse direction Y.

[0100] The arrangements described above allow for the provision of a battery cell 1 in which the grouping formed by the cover 6 and the assembly 7 facilitates its positioning in the housing 9 defined by the casing 4. Indeed, the stop surface s25 of each foldable stop 25 prevents a translation of the current collection tab 55 in the direction of insertion of the corresponding electrode assembly 50 into the housing 9 of the casing 4. Thus, the two lateral arms 21 allow for the fine positioning of the electrode assembly 50 51, 53 according to the direction of insertion of said electrode assembly 50 51, 53 into the housing 9 of the casing 4.

[0101] Finally, and as illustrated in Figure 5, the invention relates to a method for manufacturing a battery cell 1 as described above.

[0102] The process first includes a supply step E1 of an assembly 7 and a prismatic housing 4 having a top opening 8 and internally delimiting a housing 9, as well as a provision step E2 of at least two electrode assemblies 50 51, 53. In order to position the assemblies 50 relative to the cover 6 of the assembly 7, the manufacturing process includes a preliminary positioning step E3, in which the current collection tabs 55 of the first electrodes 51 bear respectively on one and the other of the stop surfaces S25 of the foldable stops 25 of the primary current collector 10.

[0103] It is thus possible to implement a first connection step E4, in which for each lateral arm 21, the folding stop 25 is folded around the current collection tab 55 which rests on this folding stop 25, so as to place the corresponding main body 23 in electrical contact with this current collection tab 55. Such a step is visible in figure 3.

[0104] A second connection step E5 is also implemented, in which the secondary current collector 30 is brought into electrical contact with the second electrodes 53. For example, this second connection step E5 may include, for each lateral leg 41 of the secondary current collector 30, the insertion of one of the current-collecting tabs 55 of the second electrodes 53 between the contact surface s41 and the bending blade 43. Thus, the manufacturing process makes it possible to fix the current-collecting tabs 55 of the first electrodes 51 on the one hand with the primary current collector 10, thereby fixing at least one translation between the assembly 7 and the electrode assemblies 51, 53, and on the other hand to fix the second electrodes 53 with the secondary current collector 30, thus fixing at least one other translation between the assembly 7 and the electrode assemblies 51, 53. 53.

[0105] The process can then include a welding step E6 carried out after the first connection step E4, in which the main body 23 of each lateral arm 21 of the primary current collector 10 is welded to the current-collecting tab 55 with which it is in electrical contact. Advantageously, the first connection step E4 allows the main body 23 of each lateral arm 21 to remain in contact with one of the current-collecting tabs 55, thus facilitating the welding step E6.

[0106] Finally, the manufacturing process includes an introduction step E7, in which the group formed by the assembly 7 and the electrode assemblies 51, 53 is introduced into the housing 9 of the casing 4, so that the cover 6 ensures a tight seal of the upper opening 8 of the casing 4.

[0107] The arrangements described above allow us to propose a method for manufacturing a prismatic battery cell 1 in which the position of the electrode assemblies 50 51, 53 relative to the cover 6 is controlled by the butting of the current collection tabs 55, and by the folding of the foldable stops 25, during the preliminary positioning step E3, and during the first connection step E4.

Claims

DEMANDS 1. Primary current collector (10) for prismatic electric battery cell (1) comprising: - an upper part (11) intended to be electrically connected to a terminal (2, 3) of the battery cell (1); and - a lateral portion (20), forming at a non-zero angle with the upper portion (11) and intended to be electrically connected to current-collecting tabs (55) of an electrode (51) of the battery cell (1), the lateral portion (20) comprising at least two lateral arms (21) comprising a proximal end portion (21p) integral with the upper portion (11), and a free distal end portion (21d); each lateral arm (21) comprising: • a main body (23) extending in a lateral direction (Z) and intended to come into electrical contact with a current-collecting tab (55); and • a foldable stop (25) forming the free distal end portion (21d) of said lateral arm (21), said foldable stop (25) being folded around a folding axis (X) substantially perpendicular to the lateral direction (Z), so as to form a stop surface (s25) at the level of which said current collection tab (55) is intended to come to rest.

2. Primary current collector (10) according to claim 1, wherein, for each lateral arm (21), a thickness of the main body (23) is strictly greater than a thickness of the foldable stop (25).

3. Primary current collector (10) according to any one of claims 1 or 2, wherein the foldable stops (25) of the two lateral arms (21) are folded outwards so that the distal ends of the two lateral arms (21) move away from each other.

4. Primary current collector (10) according to any one of claims 1 to 3, wherein for each lateral arm (21), the foldable stop (25) forms an angle with the main body (23) less than or equal to 90°.

5. Assembly (7) for prismatic electric battery cell (1) comprising: - a cover (6) comprising a first terminal (2) and a second terminal (3) of opposite polarity to the first terminal (2); - a primary current collector (10) electrically connected on one side to the first terminal (2) and intended on the other side to be electrically connected to first electrodes (51); and - a secondary current collector (30) electrically connected on one side to the second terminal (3) and intended on the other side to be electrically connected to second electrodes (53) distinct from the first electrodes (51); assembly (7) wherein the primary current collector (10) is a primary current collector (10) according to any one of claims 1 to 4.

6. Assembly (7) according to claim 5, wherein the secondary current collector (30) comprises: - an upper section (31) electrically connected to the second terminal (3) of the cover (6); and - a lateral section (40), forming a non-zero angle with the upper section (31) and intended to be electrically connected to current collection tabs (55) of the second electrodes (53) of the battery cell (1), the lateral section (40) comprising at least two lateral tabs (41) each extending in the lateral direction (Z) between a proximal end (41p) integral with the upper section (31), and a free distal end (41d); each lateral tab (41) having a contact surface (s41) intended to come into electrical contact with one of the current collection tabs (55) of the second electrodes (53), each lateral tab (41) further comprising a folding blade (43) folded about an axis substantially parallel to the lateral direction (Z).

7. Prismatic battery cell (1) for an electric propulsion vehicle, said battery cell (1) comprising: - a casing (4) having a prismatic shape, the casing (4) having a top opening (8) and internally delimiting a housing (9); - at least two assemblies (50) of electrodes (51, 53) arranged in the housing (9) where each assembly (50) comprises the successive assembly of first and second electrodes (51, 53) of opposite polarity and separated from each other by a porous separator film; the first electrodes (51) each having a current-collecting tab (55) projecting from the assembly (50) and configured to collect an electric current from said first electrode (51); - an assembly (7) according to any one of claims 5 or 6, wherein the cover (6) provides a tight seal for the upper opening (8) of the housing (4), wherein the secondary current collector (30) is electrically connected to the second electrodes (53), and wherein the lateral arms (21) of the primary current collector (10) are respectively in electrical contact with one of the current collection tabs (55) of the first electrodes (51), the folding stops (25) being folded around the current collection tabs (55) of the first electrodes (51) so that each current collection tab (55) is pinched between the main body (23) and the folding stop (25) of the corresponding lateral arm (21).

8. Battery cell (1) according to claim 7, wherein: - the housing (9) has a housing width (L9) measured along a transverse direction (Y) defined perpendicular to the folding axis (X) and to the lateral direction (Z); in which - the two electrode assemblies (50) (51, 53) each have an assembly thickness (e50a, e50b) measured along the transverse direction (Y); and in which - the two lateral arms (21) are separated from each other by a positioning distance (D), said positioning distance (D) being strictly greater than the sum of the halves of said assembly thicknesses (e50a, e50b), and being strictly less than the difference between the housing width (L9) and the sum of the halves of said assembly thicknesses (e50a, e50b).

9. Battery cell (1) according to any one of claims 7 or 8, wherein the side arms (21) have an arm length (L21) measured along the lateral direction (Z), said arm length (L21) being less than one third of a length of the housing (9) of the casing (4), measured along the lateral direction (Z).

10. Battery cell (1) according to any one of claims 7 to 9, wherein each current collection tab (55) and each main body (23) has a width (L55, L23) measured along an axis parallel or coincident with the folding axis (X), a width (L23) of a main body (23) being substantially equal to a width (L55) of the current collection tab (55) with which said main body (23) is in electrical contact.

11. Battery cell (1) according to any one of claims 7 to 10, wherein the primary current collector (10) and the current-collecting tabs (55) of the first electrodes (51) are formed of the same material 12. Battery cell (1) according to claim 11, wherein the material of the primary current collector (10) and of the current collection tabs (55) of the first electrodes (51) comprises aluminum.

13. Battery cell (1) according to any one of claims 7 to 12, wherein the main body (23) of each lateral arm (21) is welded to the current-collecting tab (55) with which said main body (23) is in electrical contact.

14. Battery cell (1) according to any one of claims 7 to 13, wherein the assembly (7) is an assembly (7) according to claim 6, and wherein the second electrodes (53) each have a current-collecting tab (55) projecting from the assembly (50) and configured to collect an electric current from said second electrode (53), each folding blade (43) of the side tabs (41) of the secondary current collector (30) being folded over one of the current-collecting tabs (55) of the second electrodes (51).

15. A method for manufacturing a battery cell (1) according to any one of claims 7 to 14, the method comprising the following steps: - a preliminary positioning step (E3), in which the current collection tabs (55) of the first electrodes (51) bear respectively on one and the other of the stop surfaces (S25) of the foldable stops (25) of the primary current collector (10); - a first connection step (E4), in which for each lateral arm (21), the folding stop (25) is folded around the current collection tab (55) which rests on this folding stop (25), so as to place the corresponding main body (23) in electrical contact with this current collection tab (55); - a second connection stage (E5), in which the secondary current collector (30) is brought into electrical contact with the second electrodes (53); - an introduction step (E7), in which the group formed by the assembly (7) and the electrode assemblies (50) (51, 53) is introduced into the housing (9) of the case (4), the cover (6) ensuring a tight seal of the upper opening (8) of the case (4).

16. Manufacturing method according to claim 15, further comprising a welding step (E6) carried out after the first connection step (E4), in which the main body (23) of each lateral arm (21) of the primary current collector (10) is welded to the current collection tab (55) with which it is in electrical contact.

17. A method for manufacturing according to any one of claims 15 or 16 a battery cell (1) according to claim 14, wherein the supply step (E1) comprises supplying an assembly (7) according to claim 7, the second connection step (E5) then comprising for each lateral leg (41) of the secondary current collector (30), the insertion of one of the current collection tabs (55) of the second electrodes (53) between the contact surface (s41) and the bending blade (43).

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