Battery pack for a motor vehicle

Abstract

Battery pack for a motor vehicle. Battery pack (3) comprising: - at least one holder (8) for retaining an electrochemical cell (4) or a group of electrochemical cells (4), and - at least one first retaining rail (11) for retaining the at least one holder, the first retaining rail extending along a first side (9A) of the at least one holder, the at least one holder comprising a first lug (10) projecting from said first side, the first retaining rail comprising a first housing (13) for cooperating with the first lug, the first housing comprising an insertion zone (14) for inserting the first lug into the first housing, a retention zone (15) for retaining the first lug in the first housing, and an extraction zone (16) for extracting the first lug from the first housing. Figure for abbreviation: Figure 2

Description

Title of the invention: Battery pack for a motor vehicle Technical field of the invention

[0001] The invention relates to a battery pack, in particular a battery pack for a vehicle, in particular a motor vehicle. The invention also relates to a vehicle comprising an electric motor capable of driving the vehicle's drive wheels, and such a battery pack, electrochemical cells of the battery pack being intended to supply the electric motor with electrical energy. The invention also relates to a method for assembling and a method for disassembling such a battery pack. Prior art

[0002] So-called electric or hybrid motor vehicles comprise at least one electric motor and a battery pack designed to supply the electric motor with electrical energy. Battery packs generally comprise a casing containing a set of electrochemical modules commonly referred to as a "stack." These electrochemical modules are attached, notably by screws, to the casing. Each electrochemical module comprises a set of electrochemical cells. The electrochemical cells are electrically connected to each other in such a way as to provide an electric current to power the electric motor.

[0003] Each electrochemical cell is therefore doubly conditioned: firstly by the casing of the electrochemical module to which it belongs, and secondly by the battery pack housing. Such an architecture is relatively bulky. The energy storage capacity of such a battery pack is therefore relatively limited for a given volume.

[0004] To overcome this drawback, so-called "cell-to-pack" battery packs are known, in which the electrochemical cells are directly attached to the battery pack casing by gluing. The electrochemical cells are embedded in a volume of glue sealed by said casing.

[0005] Such an architecture makes maintenance operations very complicated because the cells are difficult to access. In particular, such a battery pack does not allow for the individual replacement of an electrochemical cell within the battery pack. Presentation of the invention

[0006] The object of the invention is to provide a battery pack that remedies the above disadvantages and improves upon known prior art battery packs.

[0007] More specifically, a first object of the invention is a compact battery pack comprising a set of electrochemical cells that can be easily assembled or disassembled. Summary of the invention

[0008] The invention relates to a battery pack comprising: - at least one support intended to hold an electrochemical cell or a group of electrochemical cells, and - at least one first retaining rail suitable for retaining at least one support, the first retaining rail extending along a first side of at least one support, the at least one support comprising a first lug projecting from said first side, the first retaining rail comprising a first housing intended to cooperate with the first lug, the first housing comprising an insertion zone for inserting the first lug into the first housing, a retaining zone intended to retain the first lug in the first housing, and an extraction zone for extracting the first lug from the first housing.

[0009] According to one embodiment, said holding zone is positioned between the insertion zone and the extraction zone.

[0010] According to one embodiment, the insertion zone includes a base forming a first vertical stop for the first lug when the first lug is in the insertion zone, and the holding zone includes a base forming a second vertical stop for the first lug when the first lug is in the holding zone, the base of the holding zone being positioned below the base of the insertion zone.

[0011] According to one embodiment, the at least one first retaining rail comprises an upper face including a first opening, the first lug being intended to pass through the first opening to insert into the insertion zone, the upper face comprising a second opening distinct from the first opening, the first lug being intended to pass through the second opening to extract from the extraction zone.

[0012] According to one embodiment, the battery pack includes a housing intended to be fixed to a vehicle chassis, at least one retaining rail being fixed to said housing.

[0013] According to one embodiment, the housing includes a lower plate on which at least one support is intended to rest, and the battery pack includes a layer of a thermally conductive elastic material extending between at least one support and the lower plate.

[0014] According to one embodiment, the battery pack includes a second retaining rail adapted to hold at least one support, the second retaining rail extending along a second side of the at least one support, the second side being opposite the first side of the support, the at least one support comprising a second lug projecting from said second side, the second retaining rail including a second housing intended to cooperate with the second lug, the second housing comprising an insertion zone for inserting the first lug into the second housing, a retention zone intended to hold the second lug in the second housing, and an extraction zone for extracting the second lug from the second housing.

[0015] The invention also relates to a motor vehicle comprising an electric motor capable of driving the drive wheels of the vehicle, and a battery pack as defined above, the electrochemical cells of the battery pack being intended to supply the electric motor with electrical energy.

[0016] The invention also relates to a method for assembling a battery pack as defined above, the assembly method comprising: - the supply of at least one support intended to hold an electrochemical cell or a group of electrochemical cells, the at least one support comprising a first lug projecting from a first side of the at least one support, - the provision of at least one first retaining rail capable of holding at least one support, the first retaining rail comprising a first housing intended to cooperate with the first lug, the first housing comprising an insertion zone for inserting the first lug into the first housing, a retaining zone intended to hold the first lug in the first housing, and an extraction zone for extracting the first lug from the first housing, then - the insertion of the first lug into the insertion zone of the first housing by a substantially vertical displacement of at least one support, then - the displacement of the first lug from the insertion zone to the retention zone of the first housing by a substantially horizontal displacement of at least one support.

[0017] The invention also relates to a method for disassembling a battery pack as defined above, the disassembly method comprising: - the displacement of the first lug from the retention zone to the extraction zone of the first housing by a substantially horizontal displacement of at least one support, then - the extraction of the first lug from the extraction zone of the first housing by a substantially vertical displacement of at least one support. Presentation of the figures

[0018] These objects, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, with reference to the accompanying figures, among which:

[0019] Fig. 1 is a schematic view of a motor vehicle according to one embodiment of the invention.

[0020] Figure [Fig. 2] is a perspective view of part of a battery pack according to a mode of the realization of the invention.

[0021] Fig. 3 is a perspective view of a battery pack support.

[0022] Fig. 4 is a perspective view of part of a rail of the battery pack.

[0023] Fig. 5 is a perspective view of the support of Fig. 3 assembled to the part of rail of the [Fig.4]. Detailed description

[0024] Figure 1 schematically illustrates a motor vehicle 1 according to an embodiment of the invention. The vehicle 1 may be, for example, a passenger car, a commercial vehicle, a truck, or even a bus. The vehicle 1 is an "electric" vehicle. It comprises an electric motor 2 capable of driving the vehicle's rotating drive wheels, and a battery pack 3 electrically connected to the electric motor 2, to supply the electric motor 2 with electrical energy. The direct current supplied by the battery pack can be converted into alternating current by a power electronic converter to supply the electric motor 2 with alternating current. Alternatively, the vehicle 1 could also be a "hybrid" vehicle, that is, a vehicle comprising an internal combustion engine in addition to the electric motor 2.Vehicle 1 can thus comprise a plurality of motors, for example one motor per axle of the vehicle. Alternatively, the invention can also be adapted to equip other types of vehicles than motor vehicles, for example boats, or even equipment that is not a vehicle, such as stationary energy storage devices.

[0025] The battery pack 3 is an electrochemical energy storage device. The battery pack 3 comprises a set of electrochemical cells 4 capable of generating an electric current. Each electrochemical cell 4 may, in particular, include an anode, a cathode, and an electrolyte arranged between the anode and the cathode. Each electrochemical cell 4 may, for example, be of the lithium-ion type. The electrochemical cells 4 are electrically connected in series or in parallel so that the battery pack 3 delivers an appropriate electric current and voltage.

[0026] Figure 2 illustrates battery pack 3 in more detail. Battery pack 3 comprises a casing 5, through which the battery pack is attached to a vehicle chassis. The battery pack 3 may extend under a vehicle passenger compartment. The casing 5 may include a metal frame 6 and a lower plate 7. The lower plate 7 can extend substantially horizontally when the vehicle 1 is resting on a horizontal surface. The metal frame 6 can extend vertically along a contour of the lower plate 7. The lower plate 7 may have a generally rectangular contour.

[0027] The lower plate 7 may include a cooling plate. In particular, the lower plate 7 may include a hydraulic circuit in which a coolant is intended to circulate to cool the battery pack.

[0028] The battery pack 3 further comprises a set of supports 8, each support holding one or more electrochemical cells 4. In [Fig. 2], only two supports 8 are shown. However, the number of supports 8 in the battery pack may, of course, be different from two. The battery pack 3 may, in particular, comprise a number of distinct supports ranging from one to four hundred. The battery pack 3 may comprise several rows of supports extending side by side. For example, the battery pack may comprise two rows of ten supports 8. The supports 8 preferably extend side by side and thus form a single layer of supports.

[0029] The supports 8 rest on the lower plate 7. Advantageously, a layer of a thermally conductive elastic material, generally referred to by the English term "gap filler," extends between the supports 8 and the lower plate 7. This layer of thermally conductive elastic material may be in the form of an adhesive paste. Alternatively, a battery pack comprising several superimposed layers of supports could be considered.

[0030] In [Fig.2], the electrochemical cells 4 are not shown. Each Support 8 can include a number of electrochemical cells ranging, for example, from one to fifty. The electrochemical cells 4 can, for example, have a parallelepiped shape or a cylindrical shape.

[0031] A support 8 is illustrated in more detail in [Fig. 3]. Each support 8 may include a housing containing one or more electrochemical cells 4. Such a housing may include a base surrounded by side walls. As shown in [Fig. 3], the base and side walls may be solid. Alternatively, these walls may also be perforated, for example, mesh walls. Alternatively, the support could also include no base and / or only a portion of the side walls shown in [Fig. 3]. More generally, each support 8 may, in particular, adopt any shape suitable for holding one or more electrochemical cells 4.

[0032] Each support 8 comprises a first side 9A and a second side 9B, opposite the first side. Each of the two sides 9A and 9B comprises a lug 10 projecting outwards from the support 8. As shown in [Fig. 3], the lugs 10 can in particular, they could have a prismatic shape. Alternatively, the lugs 10 could have a different shape, for example, a cylindrical shape. According to other variations, each support 8 could include only one lug projecting from one side of the support. Each support could also include at least two lugs projecting from each of the two faces 9A and / or 9B.

[0033] Each lug 10 is designed to cooperate with a retaining rail 11 to hold the support 8 within the battery pack. Thus, the battery pack also includes at least one retaining rail 11 fixed to the housing 5. The retaining rail 11 can, for example, be welded, glued, riveted, or screwed to the housing 5.

[0034] According to the embodiment presented, the battery pack comprises four retaining rails 11 extending parallel to each other. Each retaining rail 11 extends along one side 9A or 9B of a support. Each row of supports 8 cooperates with a pair of retaining rails 11. The retaining rails may extend along the entire length of the lower plate 7 of the housing. The retaining rails 11 may extend parallel to a longitudinal axis of the vehicle, that is, parallel to an axis along which the vehicle moves in a straight line. Alternatively, the retaining rails 11 may extend parallel to a transverse axis of the vehicle. In a variant, the number of retaining rails could be different from four, for example, one retaining rail, two retaining rails, three retaining rails, or any number greater than four.

[0035] Each retaining rail 11 can, for example, be made from an aluminum profile. Alternatively, each retaining rail 11 can be obtained by injecting plastic material into an injection mold, in particular a fiber-reinforced plastic material to increase the strength of the retaining rail. Each retaining rail 11 can be a single piece or, conversely, be formed by assembling several rail sections 12 arranged end-to-end. Each rail section 12 can be identical to the other rail sections 12. Each rail section 12 can cooperate with a single lug 10.

[0036] Figure 4 illustrates in more detail a portion of rail 12. It is assumed that this portion of rail 12 cooperates with the lug 10 protruding from side 9A of the support. A portion of rail symmetrical to the portion of rail 12 can cooperate with the lug 10 protruding from side 9B of the support.

[0037] The rail portion 12 includes a housing 13 designed to cooperate with a lug 10 to retain the support 8 in the battery pack 3. The housing 13 includes an insertion zone 14, a retention zone 15, and an extraction zone 16. The insertion zone 14 is configured to allow the lug 10 to be inserted into the housing 13 and guided to the retention zone 15. The retention zone 15 is configured to hold the lug 10 in the housing 13. The retention zone notably provides Stop surfaces prevent movement of the support in at least one direction. The extraction zone 16 is configured to allow extraction of the lug 10 from the housing 13.

[0038] The support 8 is designed to be inserted into the battery pack 3 by inserting the lug 10 into the slot 13 through the insertion zone 14, and then moving the lug 10 to the retention zone 15. To remove the support from the battery pack 3, the lug moves from the retention zone 15 to the extraction zone 16. The insertion zone 14 is separate from the extraction zone 16. Thus, the support 8 is designed to follow two distinct trajectories for its insertion and removal from the battery pack. Each of these two trajectories can be adapted to the handling and accessibility requirements during the insertion and, respectively, the removal of a support from the battery pack 3.

[0039] The extraction zone 16 communicates with the insertion zone 14 via the retention zone 15. The insertion zone 14, retention zone 15, and extraction zone 16 are positioned side by side. The retention zone 15 is positioned between the insertion zone 14 and the extraction zone 16. Thus, to extract the battery pack holder 3, the lug passes from the retention zone 15 to the extraction zone 16 without passing through the insertion zone 14.

[0040] The rail section 12 is now described in more detail. The rail section 12 is contained within a generally parallelepiped-shaped enclosure. With reference to [Fig. 4], this enclosure comprises an upper face 17, a lower face 18, a first lateral face 19 facing the side 9A of the support from which the lug 10 protrudes, and a second lateral face 20 opposite the first lateral face 19. The rail section further comprises a third lateral face 21 and a fourth lateral face 22, each facing an adjacent rail section 12 or the metal frame 6.

[0041] The upper face 17 includes a first opening 23 leading into the insertion zone 14, and a second opening 24 leading into the extraction zone 16. Between the first opening 23 and the second opening 24, the upper face 17 includes a retaining wall 25 extending above the retaining zone 15. The retaining wall 25 is intended to prevent vertical displacement of the lug 10 when the lug is in the retaining zone 10. The retaining wall 25 is formed in the upper face 17 of the rail portion 12. The retaining wall 25 is connected to the rest of the upper face 17 by an arm 26 that borders the second opening 24. Alternatively or in addition, the retaining wall 25 could also be connected to the rest of the upper face 17 by an arm that borders the first opening 23.

[0042] The portion of the first lateral face 19 opposite the housing 13 is open so that the lug, which is integral with the support 8, can pass through the insertion zone 14 to the retention zone 15 and then to the extraction zone 16. As can be seen in [Fig. 4], the portion of the second lateral face 20 opposite the housing 13 is also open. Thus, the housing 13 opens onto each of the two lateral faces 19 and 20. The housing 13 is therefore an opening through the thickness of the rail section 12. Alternatively, the portion of the second lateral face 20 opposite the housing 13 could be solid in order to increase the rigidity of the rail section 12 and, in particular, the rigidity of the retaining wall 25.

[0043] The insertion zone 14 includes a base 27 forming a first vertical stop for the lug 10 when the lug 10 is in the insertion zone. The retention zone 15 includes a base 28 forming a second vertical stop for the lug when the lug 10 is in the retention zone. The base 28 of the retention zone is positioned below the base 27 of the insertion zone. In other words, the bottom of the housing 13 includes a descending step when traversing it from the insertion zone 14 to the retention zone 15. A riser 29 thus extends vertically on an edge of the retention zone 15. This riser 29 forms a lateral stop for the lug 10. The riser 29 is positioned substantially below the retention wall 25. The extraction zone 16 includes a bottom 30 extending at the same level as the bottom 28 of the retention zone.

[0044] To assemble a support 8 to a rail section 12, the following procedure can be used. First, the lug 10 is inserted into the insertion zone 14 of the housing 13 of a rail section 12 by moving the support 8 in a substantially vertical downward direction. The lug thus passes through the first opening 23 until it rests against the bottom 27 of the insertion zone 14. Next, the support 8 is moved horizontally so that the lug 10 slides along the bottom 27 of the insertion zone until it reaches the retaining zone 15. During this sliding motion, the support 8 is slightly raised relative to the lower plate 7 and therefore does not rub against it.Once the lug 10 is in the holding zone, it descends along the riser 29 until the support 8 or the electrochemical cells it contains come into contact with the lower plate 7, specifically with the layer of thermally conductive elastic material. The support 8 or the electrochemical cells 4 approach the layer of thermally conductive elastic material through a vertical movement, which promotes good contact between the support 8 or the electrochemical cells 4 and this layer of thermally conductive elastic material. The lug 10 is then in contact with the bottom 28 of the holding zone 15 or a short distance from the bottom 28. The trajectory followed by the lug 10 during the placement of the support 8 in the battery pack 3 is illustrated by the first arrow Fl in [Fig. 5].

[0045] Once the lug 10 is in the retaining zone 15, lateral movement of the support 8 is blocked by the stop of the lug 10 against the riser 29. The upward movement of the support 8 is limited by the stop of the lug 10 against the retaining wall 25. Other potential movements of the support 8 can be blocked or limited, for example, by the support 8 bearing against an adjacent support or by an additional fastening means. Note that if the lower plate 7 is covered with a layer of a thermally conductive elastic material, this layer may also include an adhesive component, thus providing an additional fastening means.

[0046] To disassemble a support 8 from a rail section 12, the following procedure can be used. First, the support 8 is moved horizontally so that the lug 10 slides along the bottom 28 of the retaining area until it reaches the extraction area 16. Once the lug 10 is in the extraction area, the support 8 is lifted by a substantially vertical upward movement. The lug then exits the housing 13 through the second opening 24. The path followed by the lug 10 during the extraction of the support 8 from the battery pack 3 is illustrated by a second arrow F2 in [Fig. 5]. Assuming that the lower plate 7 is covered with a layer of thermally conductive elastic material, the horizontal movement of the support prior to its vertical movement is advantageous because it allows the support or the electrochemical cells to be detached from this layer of thermally conductive elastic material.Advantageously, the horizontal displacement of the lug between the holding zone and the extraction zone is greater than or equal to 1 cm so as to properly detach the support from the layer of thermally conductive elastic material.

[0047] As a side note, during insertion or removal from the battery pack, the support 8 is moved in a translational motion. The interaction just described with the protruding lug on side 9A of the support can therefore be transposed to the protruding lug 10 on side 9B of the same support 8. The protruding lugs on both sides 9A and 9B of the support 8 can thus be simultaneously engaged and disengaged from their respective housings.

[0048] Finally, each support is thus held at two points by means of two retaining rails extending on either side of the support. If a support had only one lug, it would only be held at one point. According to another embodiment, side 9A and / or side 9B of each support could include at least two protruding lugs, each lug cooperating with a housing as described above. Such a variant would further improve the retention of the support 8.

[0049] Thanks to the invention, each support 8 can be easily assembled or disassembled from the battery pack, which facilitates the initial assembly of the battery pack and any subsequent maintenance operations. The electrochemical cell retention device 4 is simple to manufacture and compact, which leaves a large free volume for electrochemical cells.

Claims

Demands

1. Battery pack (3) comprising: - at least one holder (8) for holding an electrochemical cell (4) or a group of electrochemical cells (4), and - at least one first retaining rail (11) capable of holding the at least one holder, the first retaining rail extending along a first side (9A) of the at least one holder, the at least one holder comprising a first lug (10) projecting from said first side, the first retaining rail comprising a first housing (13) for cooperating with the first lug, the first housing comprising an insertion zone (14) for inserting the first lug into the first housing, a retaining zone (15) for retaining the first lug in the first housing, and an extraction zone (16) for extracting the first lug from the first housing, the at least one first retaining rail (11) comprising an upper face (17) comprising a first opening (23),the first lug (10) being intended to pass through the first opening to insert into the insertion zone (14), the upper face comprising a second opening (24) distinct from the first opening, the first lug (10) being intended to pass through the second opening to extract itself from the extraction zone (16).

2. Battery pack (3) according to the preceding claim, characterized in that said holding area (15) is positioned between the insertion area (14) and the extraction area (16).

3. Battery pack (3) according to any one of the preceding claims, characterized in that the insertion zone (14) comprises a base (27) forming a first vertical stop for the first lug (10) when the first lug is in the insertion zone, and in that the retention zone (15) comprises a base (28) forming a second vertical stop for the first lug when the first lug is in the retention zone, the base (28) of the retention zone being positioned below the base (27) of the insertion zone.

4. Battery pack (3) according to any one of the preceding claims, characterized in that it comprises a housing (5) intended to be fixed to a vehicle chassis, at least one retaining rail (11) being fixed to said housing.

5. Battery pack (3) according to the preceding claim, characterized in that the housing (5) comprises a lower plate (7) on which at least one support (8) is intended to rest, and in that the battery pack comprises a layer of a thermally conductive elastic material extending between at least one support and the lower plate.

6. Battery pack (3) according to any one of the preceding claims, characterized in that it comprises a second retaining rail (11) capable of retaining at least one support (8), the second retaining rail extending along a second side (9B) of the at least one support, the second side (9B) being opposite the first side (9A) of the support, the at least one support comprising a second lug (10) projecting from said second side, the second retaining rail comprising a second housing (13) intended to cooperate with the second lug, the second housing comprising an insertion area (14) for inserting the first lug into the second housing, a retaining area (15) intended to retain the second lug in the second housing, and an extraction area (16) for extracting the second lug from the second housing.

7. Motor vehicle (1), characterized in that it comprises an electric motor (2) capable of driving the drive wheels of the vehicle, and a battery pack (3) according to any one of the preceding claims, the electrochemical cells (4) of the battery pack being intended to supply the electric motor with electrical energy.

8. A method for assembling a battery pack (3) according to any one of claims 1 to 6, characterized in that it comprises: - providing at least one support (8) for holding an electrochemical cell (4) or a group of electrochemical cells (4), the at least one support comprising a first lug (10) projecting from a first side (9A) of the at least one support, - providing at least one first retaining rail (11) suitable for holding the at least one support, the first retaining rail comprising a first housing (13) for cooperating with the first lug (10), the first housing comprising an insertion zone (14) for inserting the first lug into the first housing, a retention zone (15) for holding the first lug in the first housing, and an extraction zone (16) for extracting the first lug from the first housing,

9. Then - the insertion of the first lug (10) into the insertion zone (14) of the first housing by a substantially vertical displacement of at least one support, then - the displacement of the first lug (10) from the insertion zone (14) to the retention zone (15) of the first housing by a substantially horizontal displacement of at least one support. A method for disassembling a battery pack (3) according to any one of claims 1 to 6, characterized in that it comprises: - the displacement of the first lug (10) from the retention zone (15) to the extraction zone (16) of the first housing by a substantially horizontal displacement of at least one support (8), then - the extraction of the first lug (10) from the extraction zone (16) of the first housing by a substantially vertical displacement of at least one support.

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