Electrical energy storage device, particularly for electric motorization of a motor vehicle

Abstract

An electrical energy storage device, particularly for the electric motorization of a motor vehicle, said device comprising at least two electrical energy storage cells (2) and at least one internal electrical connector (8) electrically linking said cells (2) in pairs to form a series (10) of cells (2), said device further comprising a protective enclosure (12), said series (10) of cells (2) and said internal connector(s) (8) being arranged inside said enclosure (12), said enclosure being capable of being folded to allow stacking of said cells (2) in a stacking direction. Figure for the abbreviation: Figure 3

Description

Title of the invention: Electrical energy storage device, particularly for electric motorization of a motor vehicle

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

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

[0003] Such batteries present a high risk of damage during impacts to the vehicle. This is particularly the case during the so-called "pole" crash test, in which the conductive blades can behave like sharp objects and penetrate the cells, severely damaging them.

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

[0005] Thanks to the casing that protects both the cells and their electrical interconnection(s), the risk of cell damage in the event of shocks is reduced. Furthermore, since the casing is foldable, it allows the invention to have a stacked cell configuration, if desired.

[0006] According to various additional features of the invention, which may be taken together or separately and which constitute so many embodiments of the invention: - said protective envelope is kept airtight, - said envelope has preforms designed to individually fit each of said cells, - said envelope is formed of two half-shells, assembled in particular by heat sealing, - the said internal electrical connector(s) electrically link 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 along said stacking direction, - said stacking has a plurality of folds and one and only one of said cells is located at one and only one of said folds, - said device further comprises at least one electrical connector, referred to as external, intended to electrically connect said cell sequence to an electrical conductor located outside said protective enclosure, said external connector being electrically connected to one of said cells, located at the end of said cell sequence, - said external electrical connector is partly located inside the protective enclosure and partly located outside said protective enclosure, - the 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 enabling the measurement of an electrical voltage between two consecutive cells in the cell sequence, - 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), - the said second passage is located opposite the said first passage, - the said second passage(s) are located at the level of the flat areas formed between two adjacent parts of the said preforms, - said device includes 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 slit and said second passage is formed of a light, said light being located opposite said slit.

[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 nested one inside the other.

[0009] According to various additional features of this variant of the invention, which may be taken together or separately and which constitute so many embodiments of the invention: - the first passages of the first and second storage devices are formed of slots and windows alternating along said sequence of cells, the measuring contactors passing through said windows being called first measuring contactors and the measuring contactors passing through said slots being called second measuring contactors, - said second passages of the first and second storage devices are formed of lights and enlarged openings, each of said lights being located opposite one of said slots and each of said enlarged openings being located opposite one of said windows so that the enlarged openings alternate with the lights along said sequence 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, - the said first and second contactors passing through the same of said windows and / or the same of said enlarged openings are spaced apart from each other in order to avoid any contact between them, - the said first and second measuring contacts have an identical shape, - the 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 objects, details, features and advantages thereof will become more apparent in the course of the detailed explanatory description that follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the accompanying 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 sequence of cells, formed with cells from [Fig.1],

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

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

[0015] [Fig.5] schematically illustrates in perspective a detail of the sequence of cells of [Fig. 2], from a first viewpoint,

[0016] [Fig.6] reproduces [Fig.6] from another viewpoint,

[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 part, a series of cells of a variant according to the invention,

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

[0020] [Fig. 10] schematically illustrates in perspective, partially and exploded view, an example of a device according to the invention, before folding of its sequence of cells, said sequence 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 example of an 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 a variant 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", ... are used only to distinguish the components concerned from each other and do not imply any order or 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, particularly for an electric motor of a motor vehicle. Such a device is sometimes referred to as a battery or a battery pack.

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

[0028] Figure 1 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. 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 flat shape and is elongated along a longitudinal direction X. It comprises two large, parallel, opposite flat 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, in this case, the longitudinal end edges.

[0030] Said device comprises at least one internal electrical connector 8. In [Fig. 1], cell 2 is equipped with two of these internal electrical connectors 8, connected respectively to each of the current collectors 4a, 4b of cell 2, in particular by ultrasonic welding. Said internal electrical connectors 8 are formed, for example, of a flat metal strip.

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

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

[0033] The device further advantageously comprises at least one electrical connector, referred to as external 9, for electrically connecting said sequence 10 of cells 2 to an electrical conductor, not shown in this figure. Such an external connector 9 is provided here at each longitudinal end of the sequence 10 of cells 2. The external connector(s) 9 are thus electrically connected to one of said cells 2, located at the end of said sequence 10 of cells 2.

[0034] Like the internal electrical connectors 8, the 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 comprises a protective enclosure 12. Said sequence 10 of cells 2 and said internal connector(s) 8 are arranged inside said enclosure 12. According to the illustrated embodiment, a portion of said protective enclosure 12 further provides sealing for each of said cells 2. More specifically, according to this embodiment, each of the stacks 3 forming one of said cells 2 and the corresponding portion of The aforementioned protective casing 12 forms an assembly that can be likened, for example, to a pocket cell. In addition to the electrodes already mentioned, each of these pocket cells includes an electrolyte.

[0036] The said casing 12 is also capable of being folded. It is formed, for example, of a material having inherent folding capabilities and impact protection properties, or of a rigid material with fold lines. The said protective casing 12 is preferably kept airtight.

[0037] Said casing 12 has, for example, preforms 14 designed to individually conform to each of said cells 2. Said casing 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 only during the welding phase. For example, three sides of the protective casing are welded, the electrolyte is injected, and then the fourth and final side, preferably a longitudinal side of said pocket cell, is welded.

[0038] Said external electrical connectors 9 are, for example, partly located inside the protective enclosure 12 and partly located outside said protective enclosure 12. The electrical conductors to which said external electrical connectors 9 are intended to be electrically connected are located outside said protective enclosure 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 along 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] This figure shows that only the external electrical connectors 9 open outside the envelope 12, the internal electrical connectors being entirely located inside the envelope, 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 sequence 10 of cells 2, as illustrated in [Fig. 3], constitutes a variant embodiment of the device according to the invention even though 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 to the cells by the electrically interconnecting elements, namely the internal connectors, in the event of shocks, is limited. Furthermore, by being designed to be foldable, said casing 12 allows the device according to the invention to have configurations that limit its size in different chosen directions, particularly in X or Z. In addition, preferably, as already indicated, said envelope 12 makes said cell 2 watertight.

[0043] Advantageously, said folds are adjacent and / or parallel in pairs. 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-shape, inside the envelope 12, at the level of the vertices 13 of the folds.

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

[0045] As illustrated in Figures 5 and 6, the device advantageously further comprises at least one measuring contactor 16 for measuring the electrical voltage between two consecutive cells 2 of the sequence 10 of cells. The purpose of such a voltage measurement is to ensure proper balancing of the cells 2 so that they maintain a relatively constant charge level from one cell 2 to the next for the proper functioning of the storage device. Preferably, such a measuring contactor 16 is 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 apexes 13 of the folds, as can be more clearly seen [Fig.4].

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

[0048] The measuring contacts 16 are L-shaped. A first arm 30a of the L is fixed against a face, referred to as the lower face 8a, of the corresponding internal electrical connector 8, in particular plane to plane. Another arm 30b of the L passes through the slot 18 to emerge on the other side of the internal electrical connector 8 and protrudes from a face, referred to as the upper face 8b, the lower and upper faces 8a, 8b being opposite each other.

[0049] As illustrated in [Fig. 7], said measuring contactor 16 passes through said protective enclosure 12. Said enclosure 12 here presents 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] The said second passage(s) 20 are advantageously located at the level of the flat 34 provided between two neighbors of the said preforms 14.

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

[0052] As can be seen more clearly by referring again to [Fig. 6], said sealing element 24 has, for example, a nipple shape through which the second arm 30b of said internal electrical connector 8 passes. Said nipple has a base 25a, here rectangular, bearing against the upper face 8b of said internal electrical connector 8 and / or a portion 25b projecting from the base 25a. Said portion 25b projecting from the base 25a is intended to pass through said opening 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, alternatively, in said sequence 10 of cells 2, some of said internal electrical connectors 8 have as their 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 windows 26 alternate with the internal connectors 8 with slots 18 along said sequence 10 of cells. Said windows 26 have a larger passage area than said slots 18.

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

[0056] For the first measuring contactors 16', the first arm of the L is fixed against the lower face 8a of said internal electrical connector 8, in particular plane to plane. The other arm 30b of the L passes through the window 26, along one of the edges of said window 26, to emerge on the other side of the internal electrical connector 8 and protrude 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 measure 16” is fixed to the upper face 8b of said corresponding internal electrical connectors 8 and their other arm 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, by 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 each other, or even have substantially the same size passage cross-section. The enlarged openings 28 alternate with the lights 22 along said sequence 10 of cells 2.

[0060] At the level of said windows 26, the sealing element 24 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 sequence 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, each has eight folds.

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

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

[0065] In a first 1 of the devices, illustrated in [Fig. 11], a first 101 of the folds in the sequence 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 enlarged 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 openings 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 thus has four fold vertices 13 with enlarged openings 28 and three fold vertices 13 with openings 22, respectively located on the left and right of the figure.

[0066] In a second 1' of said devices, illustrated in [Fig. 12], a first 101' of the folds of the sequence 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 openings 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 enlarged 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' thus has three fold vertices 13 with enlarged openings 28 and four fold vertices 13 with openings 22, respectively located on the right and left of 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 extension direction X of the cells 2.

[0068] It is observed that a spacing between two consecutive folds separated by one of the fold vertices 13 presenting one of the enlarged openings 28 of one of the devices 1, 1' presents a spacing allowing to accommodate two consecutive folds separated by one of the fold vertices presenting one of the lights 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 openings 22 of one of the subassemblies are located opposite one of the enlarged openings 28 of the other device. In this way, the second measuring contacts 16” of one of the devices pass alongside the first measuring contact 16” of the other device through the same window and through the same corresponding enlarged passage 28.

[0071] Said first and second contactors 16', 16" passing through the same said window and / or the same said enlarged openings 28 are advantageously spaced apart 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 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 to both 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 to both the external connectors 9 of said first and second devices 1, 1', at their last fold 108, 108'.

Claims

Demands

1. 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 (2) and at least one electrical connector (8), referred to as internal, electrically connecting said cells (2) in pairs so as to form a sequence (10) of cells (2), said device further comprising a protective enclosure (12), said sequence (10) of cells (2) and said internal connector(s) (8) being arranged inside said enclosure (12), said enclosure being capable of being folded so as to allow stacking of said cells (2) in a stacking direction (Z), said device further comprising at least one measuring contactor (16, 16', 16") located between successive cells and enabling the measurement of an electrical voltage between two consecutive cells (2) of the sequence (10) of cells, said contactor (16, 16',16”) passing through said protective envelope (12).,

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

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

4. Device according to any one of the preceding claims in which said envelope (12) is folded to form said stack of cells (2) in 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 claim 1 in which said contactor (16, 16', 16") is electrically connected to said internal electrical connector (8).

6. Device according to claim 5 in which said internal electrical connectors (8) have a first passage (17), said measuring contactor (16, 16', 16") being inserted inside said first passage (17), said enclosure (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).

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

8. Assembly formed by a first and a second storage device according to any one of claims 6 or 7, said first and second storage devices (1, 1') being nested one inside the other.

9. 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 sequence (10) of cells (2), the measuring contacts (16') passing through said windows (26) being referred to as first measuring contacts and the measuring contacts (16') passing through said slots (17) being referred to as second measuring contacts, said second passages (20) of the first and second storage devices (1, 1') being formed of lights (22) and enlarged openings (28), each of said lights (22) being located opposite one of said slots (18) and each of said enlarged openings (28) being located opposite one of said windows (26) such that the enlarged openings (28) alternate with the lights (22) along said sequence (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')-,

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