Electrical energy storage device, in particular for the electric motorization of a motor vehicle

Abstract

Electrical energy storage device, in particular for the electric motorization of a motor vehicle, said device comprising at least two electrical energy storage cells (2) and at least one electrical connector (8), called internal, electrically connecting two by two said cells (2) so as to form a series (10) of cells (2), said device further comprising a protective casing (12), said series (10) of cells (2) and said internal connector(s) (8) being arranged inside said casing (12), said casing being capable of being folded so as to allow stacking of said cells (2) in a stacking direction. Figure for the abstract: Figure 3

Description

Title of the invention: Device for storing electrical energy, in particular for the electric motorization of a motor vehicle

[0001] The invention relates to an electrical energy storage device, in particular for the electric motorization of a motor vehicle.

[0002] In this field, batteries are known comprising a plurality of electrochemical cells for storing electrical energy. The cells are arranged in a stack next to each other and electrically connected to each other by conductive strips arranged on the sides of the stack of cells.

[0003] Such batteries present a high risk of damage during impacts suffered by the vehicle. This is particularly the case during the collision test called "pole" during which the conductive blades can behave like sharp objects and penetrate inside the cells, seriously damaging them.

[0004] The invention aims to at least partially overcome the above drawbacks and to this end proposes an electrical energy storage device, in particular for the electric motorization of a motor vehicle, said device comprising at least two electrical energy storage cells and at least one electrical connector, called internal, electrically connecting said cells two by two so as to form a series of cells, said device further comprising a protective casing, said series of cells and said internal connector(s) being arranged inside said casing, said casing being capable of being folded so as to allow stacking of said cells in a stacking direction.

[0005] Thanks to the envelope which protects both the cells and their electrical interconnection(s), the risk of damage to the cells in the event of shocks is reduced. In addition, the envelope being foldable, it allows the invention to have a stacked configuration of the cells, if desired.

[0006] According to various additional characteristics of the invention, which may be taken together or separately and which form as many embodiments of the invention: - said protective envelope is kept watertight, - said envelope has preforms intended to individually fit each of said cells, - said envelope is formed of two half-shells, in particular assembled by heat-sealing, - said internal electrical connector(s) electrically connect said cells in series, - said cells have two large opposite parallel flat faces. - said stacking direction is perpendicular to said large flat faces of the cells. - said envelope is folded and said cells form a stack in said stacking direction, - said stack has a plurality of folds and one and only one of said cells is located at the level of one and only one of said folds, - said device further comprises at least one electrical connector, called external, intended to electrically connect said series of cells to an electrical conductor located outside said protective envelope, said external connector being electrically connected to one of said cells, located at the end of said series of cells, - said external electrical connector is partly located inside the protective casing and partly located outside said protective casing, - said internal and / or external electrical connector(s) are electrically connected to current collectors of said cells, in particular by ultrasonic welding, - said device further comprises at least one measuring contactor making it possible to measure an electrical voltage between two consecutive cells in the series of cells, - said contactor passes through said protective casing, - said contactor is electrically connected to said corresponding internal electrical connector, - said internal electrical connectors have a first passage, said measuring contactor being inserted inside said first passage, - said envelope has a second passage of said measuring contactor(s), - said second passage is located opposite said first passage, - said second passage(s) are located at the level of flat areas provided between two neighboring preforms, - said device comprises a sealing element at said first and / or second passages,

[0007] In a first variant of the invention, in said device, said first passage is formed of a slot and said second passage is formed of a light, said light being located opposite said slot.

[0008] In a second variant, the invention relates to an assembly formed by a first and a second storage device as described above, said first and second storage devices being fitted into one another.

[0009] According to various additional characteristics of this variant of the invention, which may be taken together or separately and which form as many embodiments of the invention: - the first passages of the first and second storage devices are formed of slots and windows alternating along said series of cells, the measuring contacts passing through said windows being called first measuring contacts and the measuring contacts passing through said slots being called second measuring contacts, - said second passages of the first and second storage devices are formed of lights and widened openings, each of said lights being located opposite one of said slots and each of said widened openings being located opposite one of said windows so that the widened openings alternate with the lights along said series of cells, - the second measuring contacts of one of said devices pass through said windows and said enlarged openings of the other of said devices, - said first and second contactors passing through the same one of said windows and / or the same one of said enlarged openings are distant from each other in order to avoid any contact between them, - said first and second measuring contacts have an identical shape, - said first and second storage devices are intended to be electrically connected in parallel, in particular via their external connectors.

[0010] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the appended schematic drawings among which:

[0011] [Fig-1] schematically illustrates in perspective a cell of an example of an electrical energy storage device according to the invention,

[0012] [Fig.2] schematically illustrates in perspective a series of cells, formed with cells of [Fig.l],

[0013] [Fig.3] illustrates schematically in exploded perspective an example of device according to the invention, before folding its sequence of cells, said sequence repeating that illustrated in [Fig.2],

[0014] [Fig.4] schematically illustrates in perspective such a device, after folding, at number of cells present,

[0015] [Fig.5] schematically illustrates in perspective a detail of the series of cells of [Fig.2], according to a first angle of view,

[0016] [Fig.6] takes up [Fig.6] from another angle of view,

[0017] [Fig.7] schematically illustrates in perspective a detail of [Fig.3], in a assembled version of said device,

[0018] [Fig.8] illustrates schematically in perspective, in a partial way, a series of cells of a variant in accordance with the invention,

[0019] [Fig.9] schematically illustrates in perspective a detail of [Fig.8],

[0020] [Fig. 10] schematically illustrates in perspective in a partial and exploded manner an example of a device in accordance with the invention, before folding its series of cells, said series being in accordance with that illustrated in figures 8 and 9,

[0021] [Fig. 11] schematically illustrates in side view a first device conforming to that illustrated in [Fig. 10], after folding,

[0022] [Fig. 12] schematically illustrates in side view a second device conforming to that illustrated in [Fig. 10], after folding,

[0023] [Fig. 13] schematically illustrates in side view an exemplary embodiment of an assembly according to the invention formed by combining the devices of figures 11 and 12,

[0024] [Fig. 14] schematically illustrates in perspective an alternative embodiment of the assembly according to the invention formed by completing the assembly of [Fig.13].

[0025] It should first be noted that the terms "first", "second", "third", etc. are only used to distinguish the components concerned from each other and do not indicate an order or a possible importance of said components or even the presence of all of them in the invention.

[0026] As illustrated in the various figures, the invention relates to an electrical energy storage device, in particular for an electric motor of a motor vehicle. Such a device is sometimes referred to as a battery or accumulator battery.

[0027] Said device comprises a plurality of electrical energy storage cells 2. Said cells 2 are for example lithium-ion accumulators.

[0028] [Fig.l] illustrates one of said cells 2. Said cell 2 comprises, for example, positive and negative electrodes here assembled in a stack 3. At this stage, according to the illustrated embodiment, said cell 2 is not yet sealed. Said cell 2 has current collectors 4a, 4b. One 4a of the current collectors forms a positive terminal of the cell, electrically connected to the positive electrode(s), and the other 4b forms a negative terminal of the cell, electrically connected to the negative electrode(s).

[0029] According to the illustrated embodiment, said cell 2 has a substantially planar and elongated shape in a longitudinal direction X. It comprises two large opposite parallel planar faces 6a, 6b connected by lateral edges. Said current collectors 4a, 4b are located at two of the opposite lateral edges of said cell 2, namely, here, longitudinal end edges.

[0030] Said device comprises at least one electrical connector 8, called internal. In [Fig.l], the cell 2 is equipped with two of these internal electrical connectors 8, connected respectively to each of the current collectors 4a, 4b of the cell 2, in particular by ultrasonic welding. Said internal electrical connectors 8 are formed, for example, of a flat metal blade.

[0031] As illustrated in [Fig.2], said internal connector(s) 8 electrically connect said cells 2 in pairs so as to form a series 10 of cells. Said internal electrical connector(s) 8 electrically connect said cells 2, for example, in series. In other words, in such a case, each cell 2 of the series 10 of cells 2 is connected in series to the preceding cell and / or to the following cell in said series 10 of cells 2.

[0032] Said cells 2 of the series 10 of cells are preferably identical. Said series 10 of cells 2 advantageously extends along said longitudinal direction X of extension of each of the cells 2.

[0033] Said device further advantageously comprises at least one electrical connector, called external 9, intended to electrically connect said series 10 of cells 2 to an electrical conductor, not illustrated in this figure. Such an external connector 9 is here provided at each longitudinal end of the series 10 of cells 2. Said external connector(s) 9 are thus electrically connected to one of said cells 2, located at the end of said series 10 of cells 2.

[0034] Like the internal electrical connectors 8, the said external electrical connector(s) 9 are electrically connected to the current collectors 4a, 4b of the corresponding cells 2, in particular by ultrasonic welding.

[0035] As illustrated in [Fig. 3], said device further comprising a protective envelope 12. Said series 10 of cells 2 and said internal connector(s) 8 are arranged inside said envelope 12. According to the illustrated embodiment, a portion of said protective envelope 12 further provides sealing to each of said cells 2. More precisely, according to this embodiment, each of the stacks 3 forming one of said cells 2 and the corresponding portion of said protective envelope 12 forms an assembly which can be compared, for example, to a pocket cell. In addition to the electrodes already mentioned, each of said pocket cells comprises an electrolyte.

[0036] Said envelope 12 is further capable of being folded. It is formed, for example, from a material which itself has folding capabilities and shock protection properties or from a rigid material provided with fold lines. Said protective envelope 12 is preferably kept watertight.

[0037] Said envelope 12 has, for example, preforms 14 intended to individually fit each of said cells 2. Said envelope 12 is here formed from an assembly of two half-shells 12a, 12b, in particular assembled by heat welding, which makes the pocket cell watertight in the illustrated embodiment. The electrolyte is, in particular, injected just during the welding phase. For example, three sides of the protective envelope are welded, the electrolyte is injected and then the fourth and last side is welded, preferably a longitudinal side of said pocket cell.

[0038] Said external electrical connectors 9 are, for example, partly located inside the protective casing 12 and partly located outside said protective casing 12. The electrical conductors to which said external electrical connectors 9 are intended to be electrically connected are located outside said protective casing 12. Welding a polymer around the external electrical connectors 9 advantageously promotes sealing.

[0039] As illustrated in [Fig.4], said envelope 12 is folded and said cells form a stack in a stacking direction Z. The stacking direction Z is here perpendicular to the longitudinal extension direction X of the cells. In other words, said stacking direction Z is perpendicular to said large flat faces of the cells.

[0040] It can be seen in this figure that only the external electrical connectors 9 open outside the casing 12, the internal electrical connectors being entirely located inside the casing, like the cells 2.

[0041] It should be noted that the devices illustrated in Figures 3 and 4 do not have the same number of folds but are otherwise identical. Furthermore, the assembly formed by the envelope 12 and the series 10 of cells 2, as illustrated in [Fig. 3] forms an alternative embodiment of the device according to the invention even if it has been chosen not to fold the envelope 12.

[0042] Thanks to the casing 12 which protects not only the cells but also the internal connectors, the risk of damage, in the event of impacts, to the cells by the elements allowing them to be electrically interconnected, namely here said internal connectors, is limited. In addition, by being designed to be foldable, said casing 12 allows the device according to the invention to have configurations making it possible to limit its size in different chosen directions, in particular in X or in Z. In addition, preferably, as already indicated, said envelope 12 makes said cell 2 watertight.

[0043] Advantageously, said folds are adjacent and / or parallel two by two. They are connected by parts of the envelope 12 protecting the internal collectors 8. In other words, the internal connectors 8 are also folded, here in a U, inside the envelope 12, at the level of the vertices 13 of the folds.

[0044] In the illustrated embodiment, said stack has a plurality of folds and one and only one of said cells 2 is located at the level of one and only one of said folds, between two of said peaks 13 of the folds.

[0045] As illustrated in Figures 5 and 6, said device advantageously further comprises at least one measuring contactor 16 making it possible to measure an electrical voltage between two consecutive cells 2 of the series 10 of cells. Such a voltage measurement aims to allow good balancing of the cells 2 between them so that they maintain a relatively constant charge level from one cell 2 to the next for good operation of said storage device. Such a measuring contactor 16 is thus preferably provided between each successive cell 2.

[0046] Said measuring contactor 16 is electrically connected, for example, to said internal electrical connector 8 located between each successive cell 2. In other words, after folding, said measuring contactors 16 are located at the level of the vertices 13 of the folds, as is better seen [Fig.4].

[0047] Said internal electrical connectors 8 have here for this purpose a first passage 17. Said first passage 17 is here formed of a slot 18. Said measuring contacts 16 are inserted inside said first passages 17, in particular said slots 18. A connection between said measuring contacts 16 and said internal connectors 8 is made, in particular, by welding. Said measuring contacts 16 are located, for example, in a central zone of said internal connectors 8. Said slot 18 extends, for example, in said direction of extension X of the cells 2.

[0048] Said measuring contactors 16 here have an L shape. A first branch 30a of the L is fixed against a face, called lower 8a, of said corresponding internal electrical connector 8, in particular plane against plane. Another branch 30b of the L passes through the slot 18 to open on the other side of the internal electrical connector 8 and to project from a face, called upper 8b, of said internal electrical connector 8, said lower and upper faces 8a, 8b being opposite each other.

[0049] As illustrated in [Fig.7], said measuring contactor 16 passes through said protective casing 12. Said casing 12 has here for this purpose a second passage 20 of said measuring contactor(s) 16, in particular in the form of a light 22. Said light 22 is located opposite said slot 18.

[0050] Said second passage(s) 20 are advantageously located at the level of flat areas 34 arranged between two neighbors of said preforms 14.

[0051] Advantageously, said measuring contactor 16 passes through said protective casing 12 in a sealed manner. Said device here comprises for this purpose a sealing element 24 between said measuring contactor 16 and said protective casing 12. Said sealing element 24 is located at said first passage 17 and / or said second passage 20.

[0052] As is better seen by referring again to [Fig.6], said sealing element 24 has, for example, a nipple shape crossed by the second branch 30b of said internal electrical connector 8. Said nipple has a base 25a, here rectangular, bearing against the upper face 8b of said internal electrical connector 8 and / or a part 25b projecting from the base 25a. Said part 25b projecting from the base 25a is intended to pass through said light 22 of the casing 12. Said nipple is made, for example, of an elastomeric material. Said sealing element is, for example, heat-sealed at the same time as the assembly of the two half-shells forming the casing 12.

[0053] As illustrated in Figures 8 to 10, as a variant, in said series 10 of cells 2, some of said internal electrical connectors 8 have as first passage 17 a passage window 26, in particular rectangular, instead of the first slot-shaped passages 18.

[0054] In the illustrated embodiment, the internal connectors 8 with window 26 alternate with the internal connectors 8 with slot 18 along said sequence 10 of cells. Said windows 26 have a larger passage section than said slots 18.

[0055] Some 16' of the measuring contacts, called first measuring contacts, are inserted inside the windows 26 and the other 16”, called second measuring contacts, are inserted into the slots 18. Said first and second measuring contacts 16', 16” preferably have an identical shape. Here, they have an L shape as in the sequence 10 of cells 2 mentioned above.

[0056] For the first measuring contacts 16', the first branch of the L is fixed against the lower face 8a of said internal electrical connector 8, in particular plane against plane. The other branch 30b of the L passes through the window 26, along one of the edges of said window 26, to open on the other side of the internal electrical connector 8 and project from the upper face 8b of said internal electrical connector 8.

[0057] Said measuring contactors 16', 16” are oriented alternately in opposite directions. More precisely, here, the first branch 30a of the second contactors of measuring 16” is fixed to the upper face 8b of said corresponding internal electrical connectors 8 and their other branch 30b protrudes from the lower face 8a of said internal electrical connectors 8.

[0058] Thanks to its enlarged section, said window 26 is configured to also allow passage of one of the second measuring contactors 16” of another electrical energy storage device according to the invention, as will be detailed below in relation to figures 13 and 14.

[0059] Said second passage 20 corresponding to the first measuring contactor 16' is formed, for example, of an enlarged opening 28 so as to correspond to said window 26. In other words, said enlarged opening 28 and said window 26 are located opposite, or even have substantially the same size passage section. The enlarged openings 28 alternate with the lights 22 along said series 10 of cells 2.

[0060] At the level of said windows 26, the sealing element 24 here has the form of an annular seal interposed between the upper face 8b of the internal electrical connectors 8 and a lower face of the casing 12. Said annular seal is, for example, made of elastomeric material. Said sealing element is, for example, heat-sealed at the same time as the assembly of the two half-shells forming the casing 12.

[0061] For the rest, the envelope 12 and the series 10 of cells of the embodiment of figures 8 to 10 is preferably identical to that of [Fig.3].

[0062] As illustrated in Figures 11 and following, the invention also relates to an assembly formed of two devices as described above in relation to Figures 8 to 10, nested one inside the other, after folding. Here they each have eight folds.

[0063] It is understood that each of said devices is provided alternately with first measuring contactors 16', that is to say passing through windows of the internal electrical connectors and the enlarged openings 28 of the casing 12, and with second measuring contactors 16” that is to say passing through slots of the internal electrical connectors and the lights 22 of the casing 12.

[0064] The tops 13 of the folds provided with the enlarged openings 28 are wider than the tops 13 of the folds provided with the lights 22.

[0065] In a first 1 of the devices, illustrated in [Fig. 11], a first 101 of the folds of the series 10 of cells 2 is located at a distance from a second 102 of the folds. They are separated by one of the vertices 13 comprising one of the widened openings 28. A third 103 of the folds is in contact with the second fold 102. They are separated by one of the vertices 13 comprising one of the lights 22. Such a pattern is repeated up to the last 108 of the folds, which is therefore at a distance from the seventh 107 of the folds. The first subset 1 therefore has four vertices 13 of folds with widened opening 28 and three vertices 13 of folds with light 22 respectively located on the left and right in the figure.

[0066] In a second 1' of said devices, illustrated in [Fig.12], a first 101' of the folds of the series 10 of cells 2 is located against a second 102' of the folds. They are separated by one of the vertices 13 comprising one of the lights 22. A third 103' of the folds is at a distance from the second fold 102'. They are separated by one of the vertices 13 comprising one of the widened openings 28. Such a pattern is repeated up to the last 108' of the folds, which is therefore against the seventh 107' of the folds. The second subset 1' therefore has three vertices 13 of folds with widened opening 28 and four vertices 13 of fold with light 22 respectively located on the right and left in the figure.

[0067] In Figures 13 and 14, the illustrated assembly comprises the first and second devices 1, 1' described above nested one inside the other, in a direction parallel to the direction of extension X of the cells 2.

[0068] It is noted that a spacing between two consecutive folds separated by one of the fold apexes 13 having one of the widened openings 28 of one of the devices 1, 1' has a spacing making it possible to accommodate two consecutive folds separated by one of the fold apexes having one of the openings 22 of the other device.

[0069] In said assembly, each fold of each of the devices 1, 1' is sandwiched between a fold of the same device and a fold of the other device, with the exception of the first fold 101 and the last fold 108 of the first device 1.

[0070] It is further understood that, between each of the folds, the apexes 13 of the folds associated with one of the lights 22 of one of the subassemblies are located opposite one of the enlarged openings 28 of the other of the devices. In this way, the second measuring contacts 16” of one of the devices pass next to the first measuring contactors 16” of the other of the devices through the same window and through the same corresponding enlarged passage orifice 28.

[0071] Said first and second contactors 16', 16” passing through the same one of said windows and / or the same one of said enlarged openings 28 are advantageously distant from each other in order to avoid any contact between them.

[0072] Said first and second storage devices 1, 1' are intended to be electrically connected in parallel, in particular via their external connectors 9.

[0073] As illustrated in [Fig. 14], said assembly further comprises here the electrical conductors connected to their external conductors 9. Said electrical conductors form terminals 40a, 40b for connecting said assembly to an electrical circuit. A first 40a of said terminals is connected both to the external connectors 9 of said first and second devices 1, 1', between each of their first folds 101, 101'. A second 40b of said terminals is connected both to the external connectors 9 of said first and second devices 1, 1', at their last fold 108, 108'.

Claims

Claims

1. Device for storing electrical energy, in particular for the electric motorization of a motor vehicle, said device comprising at least two cells (2) for storing electrical energy and at least one electrical connector (8), called internal, electrically connecting two by two said cells (2) so as to form a series (10) of cells (2), said device further comprising a protective casing (12), said series (10) of cells (2) and said internal connector(s) (8) being arranged inside said casing (12), said casing being capable of being folded so as to allow stacking of said cells (2) in a stacking direction (Z).

2. Device according to the preceding claim in which said protective envelope (12) is kept watertight.

3. Device according to any one of the preceding claims in which said envelope (12) has preforms (14) intended to individually fit each of said cells (2).

4. Device according to any one of the preceding claims wherein said envelope (12) is folded to form said stack of cells (2) according to a plurality of folds, one and only one of said cells (2) being located at one and only one of said folds.

5. Device according to any one of the preceding claims further comprising at least one measuring contactor (16, 16', 16”) making it possible to measure an electrical voltage between two consecutive cells (2) of the series (10) of cells, said contactor (16, 16', 16”) passing through said protective casing (12).

6. Device according to the preceding claim wherein said contactor (16, 16', 16”) is electrically connected to said internal electrical connector (8).

7. Device according to any one of claims 5 or 6 wherein said internal electrical connectors (8) have a first passage (17), said measuring contactor (16, 16', 16”) being inserted inside said first passage (17), said casing (12) has a second passage (20) of said measuring contactor(s) (16, 16', 16”), said second passage (20) being located opposite said first passage (17).

8. Device according to the preceding claim comprising a sealing element (24) at said first and / or second passages (17, 22).

9. Assembly formed by a first and a second storage device according to any one of claims 7 or 8, said first and second storage devices (1, 1') being nested inside each other.

10. An assembly according to the preceding claim, wherein the first passages (17) of the first and second storage devices (1, 1') are formed of slots (18) and windows (26) alternating along said series (10) of cells (2), the measuring contacts (16') passing through said windows (26) being called first measuring contacts and the measuring contacts (16”) passing through said slots (17) being called second measuring contacts, said second passages (20) of the first and second storage devices (1, 1') being formed of slots (22) and enlarged openings (28), each of said slots (22) being located opposite one of said slots (18) and each of said enlarged openings (28) being located opposite one of said windows (26) so that the enlarged openings (28) alternate with the lights (22) along said series (10) of cells (2),the second measuring contacts (16”) of one of said devices passing through said windows (26) and said enlarged openings (28) of the other of said devices (1,1')-,

Images