Battery pack for a motor vehicle and method for assembling same

Abstract

The invention relates to a battery pack (3) that comprises: - at least one support member (8) which is intended to hold an electrochemical cell (4) or a group of electrochemical cells (4); and - at least one first holding rail (11) which is capable of holding the at least one support member, the first holding rail extending along a first side (9A) of the at least one support member, the at least one support member comprising a first lug (10) projecting from this first side, the first holding rail comprising a first recess (13) which is intended to cooperate with the first lug, the first recess comprising an insertion region (14) for inserting the first lug into the first recess, a holding region (15) which is intended to hold the first lug in the first recess, and an extraction region (16) for extracting the first lug from the first recess.

Description

[0001] DESCRIPTION

[0002] TITLE: BATTERY PACK FOR A MOTOR VEHICLE AND METHOD FOR ASSEMBLING SAME

[0003] Technical field of the invention

[0004] 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 drive wheels of the vehicle, and to 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 of assembling and a method of disassembling such a battery pack.

[0005] State of the prior art

[0006] So-called electric or hybrid motor vehicles include at least one electric motor and a battery pack designed to supply the electric motor with electrical energy. Battery packs generally include a casing containing a set of electrochemical modules commonly referred to as a "stack". These electrochemical modules are attached to the casing, in particular by screwing. Each electrochemical module includes a set of electrochemical cells. The electrochemical cells are electrically connected to each other so as to provide an electrical current to power the electric motor.

[0007] Each electrochemical cell is therefore doubly conditioned: on the one hand by a housing of the electrochemical module to which it belongs, on the other hand by the casing of the battery pack. Such an architecture is relatively bulky. The energy storage capacity of such a battery pack is therefore relatively limited for a given volume. To overcome this drawback, we know of so-called "cell to pack" battery packs in which the electrochemical cells are directly fixed to the casing of the battery pack by gluing. The electrochemical cells are embedded in a volume of glue closed by said casing.

[0008] Such an architecture makes maintenance operations very complicated because the cells are difficult to access. In particular, such a battery pack does not allow individual replacement of an electrochemical cell in the battery pack.

[0009] Presentation of the invention

[0010] The aim of the invention is to provide a battery pack which overcomes the above drawbacks and improves the battery packs known from the prior art.

[0011] More specifically, a first object of the invention is a space-saving battery pack comprising a set of electrochemical cells which can be easily assembled or disassembled.

[0012] Summary of the invention

[0013] The invention relates to a battery pack comprising:

[0014] - at least one support intended to hold an electrochemical cell or a group of electrochemical cells, and

[0015] - at least one first holding rail capable of holding the at least one support, the first holding rail extending along a first side of the at least one support, the at least one support comprising a first lug projecting from said first side, the first holding 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 holding zone intended to hold the first lug in the first housing, and an extraction zone for extracting the first lug from the first housing.

[0016] According to one embodiment, said holding zone is positioned between the insertion zone and the extraction zone.

[0017] According to one embodiment, the insertion zone comprises a bottom forming a first vertical stop for the first lug when the first lug is in the insertion zone, and the holding zone comprises a bottom forming a second vertical stop for the first lug when the first lug is in the holding zone, the bottom of the holding zone being positioned below the bottom of the insertion zone.

[0018] According to one embodiment, the at least one first retaining rail comprises an upper face comprising a first opening, the first lug being intended to pass through the first opening to be inserted 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 be extracted from the extraction zone.

[0019] According to one embodiment, the battery pack comprises a casing intended to be fixed to a chassis of a vehicle, the at least one retaining rail being fixed to said casing.

[0020] According to one embodiment, the housing comprises a lower plate on which the at least one support is intended to rest, and the battery pack comprises a layer of a thermally conductive elastic material extending between the at least one support and the lower plate.According to one embodiment, the battery pack comprises a second holding rail capable of holding the at least one support, the second holding 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 holding rail comprising 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 holding zone intended to hold the second lug in the second housing, and an extraction zone for extracting the second lug from the second housing.

[0021] The invention also relates to a motor vehicle comprising an electric motor capable of driving drive wheels of the vehicle, and a battery pack as defined previously, the electrochemical cells of the battery pack being intended to supply the electric motor with electrical energy.

[0022] The invention also relates to a method of assembling a battery pack as defined above, the assembly method comprising:

[0023] - providing at least one support for holding 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,

[0024] - the provision of at least one first holding rail capable of holding the at least one support, the first holding 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 holding 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

[0025] - the insertion of the first lug into the insertion zone of the first housing by a substantially vertical movement of the at least one support, then

[0026] - the movement of the first lug from the insertion zone to the holding zone of the first housing by a substantially horizontal movement of the at least one support.

[0027] The invention also relates to a method of disassembling a battery pack as defined above, the disassembly method comprising:

[0028] - the movement of the first lug from the holding zone to the extraction zone of the first housing by a substantially horizontal movement of the at least one support, then

[0029] - the extraction of the first lug from the extraction zone of the first housing by a substantially vertical movement of the at least one support.

[0030] Presentation of figures

[0031] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures among which:

[0032] Figure 1 is a schematic view of a motor vehicle according to one embodiment of the invention.

[0033] Figure 2 is a perspective view of a portion of a battery pack according to one embodiment of the invention.

[0034] Figure 3 is a perspective view of a battery pack holder.

[0035] Figure 4 is a perspective view of a portion of a rail of the battery pack. Figure 5 is a perspective view of the bracket of Figure 3 assembled to the rail portion of Figure 4.

[0036] Detailed description

[0037] Figure 1 schematically illustrates a motor vehicle 1 according to one embodiment of the invention. The vehicle 1 may be, for example, a private vehicle, a utility vehicle, a truck or even a bus. The vehicle 1 is a so-called "electric" vehicle. It comprises an electric motor 2 capable of driving the driving wheels of the vehicle in rotation, and a battery pack 3 electrically connected to the electric motor 2, to supply the electric motor 2 with electrical energy. The direct electric current supplied by the battery pack can be transformed into alternating electric current by an electronic power converter to supply the electric motor 2 with an alternating electric current. Alternatively, the vehicle 1 could also be a so-called "hybrid" vehicle, that is to say a vehicle comprising an internal combustion engine in addition to the electric motor 2.The vehicle 1 may thus comprise a plurality of engines, for example one engine per axle of the vehicle. Alternatively, the invention may also be adapted to equip other types of vehicles than motor vehicles, for example boats, or even equipment which is not a vehicle, such as for example stationary energy storage devices.

[0038] The battery pack 3 is an energy storage device in electrochemical form. The battery pack 3 comprises a set of electrochemical cells 4 capable of generating an electric current. Each electrochemical cell 4 may in particular comprise 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 adequate electric current and an adequate electric voltage.

[0039] Figure 2 illustrates the battery pack 3 in more detail. The battery pack 3 comprises a casing 5 by means of which the battery pack is attached to a chassis of the vehicle. The battery pack 3 may in particular extend under a passenger compartment of the vehicle. The casing 5 may in particular comprise a metal frame 6 and a bottom plate 7. The bottom plate 7 may extend substantially horizontally when the vehicle 1 is resting on horizontal ground. The metal frame 6 may extend vertically along a contour of the bottom plate 7. The bottom plate 7 may comprise a generally rectangular contour.

[0040] The lower plate 7 may comprise a cooling plate. In particular, the lower plate 7 may comprise a hydraulic circuit in which a cooling liquid is intended to circulate to cool the battery pack.

[0041] The battery pack 3 further comprises a set of supports 8, each support holding one or more electrochemical cells 4. In Figure 2, only two supports 8 are shown. However, the number of supports 8 of the battery pack may of course be other than two. The battery pack 3 may in particular comprise a number of distinct supports of between one and four hundred. The battery pack 3 may comprise several rows of supports extending next to each other. For example, the battery pack may comprise two rows of around ten supports 8. The supports 8 preferably extend next to each other and thus form a single layer of supports. The supports 8 rest on the lower plate 7. Advantageously, a layer of a thermally conductive elastic material, generally referred to by the Anglicism "gap filler", extends between the supports 8 and the lower plate 7.This layer of thermally conductive elastic material can be in the form of an adhesive paste. Alternatively, a battery pack comprising several layers of superimposed supports could be considered.

[0042] In Figure 2, the electrochemical cells 4 are not shown. Each support 8 may comprise a number of electrochemical cells of, for example, between one and fifty. The electrochemical cells 4 may, for example, have a parallelepiped shape or a cylindrical shape.

[0043] A support 8 is illustrated in more detail in Figure 3. Each support 8 may comprise a housing containing one or more electrochemical cells 4. Such a housing may comprise a bottom surrounded by side walls. As shown in Figure 3, the bottom and the side walls may be solid walls. Alternatively, these walls may also be perforated, for example mesh walls. Alternatively, the support could also comprise no bottom and / or only part of the side walls shown in Figure 3. More generally, each support 8 may in particular adopt any shape making it possible to hold one or more electrochemical cells 4.

[0044] 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 outwardly from the support 8. As shown in FIG. 3, the lugs 10 may in particular have a prismatic shape. Alternatively, the lugs 10 could have a different shape, for example a cylindrical shape. According to other variants, each support 8 could comprise only one lug projecting from a single side of the support. Each support could also comprise at least two lugs projecting from each of the two faces 9A and / or 9B.

[0045] Each lug 10 is intended to cooperate with a holding rail 11 to hold the support 8 within the battery pack. Thus, the battery pack also comprises at least one holding rail 11 fixed to the casing 5. The holding rail 11 may, for example, be welded, glued, riveted or screwed to the casing 5.

[0046] According to the embodiment presented, the battery pack comprises four holding rails 11 extending parallel to each other. Each holding rail 11 extends along one side 9A or 9B of a support. Each row of supports 8 cooperates with a pair of holding rails 11. The holding rails may extend along the entire length of the lower plate 7 of the casing. The holding rails 11 may extend parallel to a longitudinal axis of the vehicle, i.e., parallel to an axis in which the vehicle is traveling in a straight line. Alternatively, the holding rails 11 may extend parallel to a transverse axis of the vehicle. Alternatively, the number of holding rails could be other than four, for example, a single holding rail, two holding rails, three holding rails, or any number greater than four.

[0047] Each holding rail 11 may, for example, be made from an aluminum profile. Alternatively, each holding rail 11 may be obtained by injecting plastic material into an injection mold, in particular a plastic material filled with fibers in order to increase the strength of the holding rail. Each holding rail 11 may be a single-piece assembly or, on the contrary, be formed by assembling several rail parts 12 arranged in the extension of one another. Each of the rail parts 12 may be identical to the other rail parts 12. Each rail part 12 may cooperate with a single lug 10.

[0048] Figure 4 illustrates in more detail a rail portion 12. It is assumed that this rail portion 12 cooperates with the lug 10 projecting from the side 9A of the support. A rail portion symmetrical to the rail portion 12 can cooperate with the lug 10 projecting from the side 9B of the support.

[0049] The rail portion 12 comprises a housing 13 intended to cooperate with a lug 10 to hold the support 8 in the battery pack 3. The housing 13 comprises an insertion zone 14, a holding zone 15 and an extraction zone 16. The insertion zone 14 is configured to allow the insertion of the lug 10 into the housing 13 and guide it to the holding zone 15. The holding zone 15 is configured to hold the lug 10 in the housing 13. The holding zone notably provides stop surfaces preventing the movement of the support in at least one direction. The extraction zone 16 is configured to allow the extraction of the lug 10 from the housing 13.

[0050] The support 8 is intended to be placed in the battery pack 3 by inserting the lug 10 into the housing 13 via the insertion zone 14, then moving the lug 10 to the holding zone 15. To extract the support from the battery pack 3, the lug moves from the holding zone 15 to the extraction zone 16. The insertion zone 14 is distinct from the extraction zone 16. Thus, the support 8 is intended to follow two distinct trajectories for its insertion and its extraction from the battery pack. Each of these two trajectories can be adapted to the constraints of maneuverability and accessibility during the insertion and respectively during the extraction of a support from the battery pack 3. The extraction zone 16 communicates with the insertion zone 14 via the holding zone 15. The insertion 14, holding 15 and extraction 16 zones are positioned next to each other.The holding zone 15 is positioned between the insertion zone 14 and the extraction zone 16. Thus, to extract the support from the battery pack 3, the lug passes from the holding zone 15 to the extraction zone 16 without passing through the insertion zone 14.

[0051] The rail portion 12 is now described in more detail. The rail portion 12 is included in an envelope of generally parallelepipedal shape. With reference to FIG. 4, this envelope comprises an upper face 17, a lower face 18, a first lateral face 19 intended to face the side 9A of the support from which the lug 10 projects, and a second lateral face 20 opposite the first lateral face 19. The rail portion further comprises a third lateral face 21 and a fourth lateral face 22 each intended to face an adjacent rail portion 12 or the metal frame 6.

[0052] The upper face 17 comprises a first opening 23 opening into the insertion zone 14, and a second opening 24 opening into the extraction zone 16. Between the first opening 23 and the second opening 24, the upper face 17 comprises a retaining wall 25 extending above the retaining zone 15. The retaining wall 25 is intended to prevent vertical movement 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 which 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 which borders the first opening 23.The portion of the first lateral face 19 facing the housing 13 is open so that the lug, which is integral with the support 8, can pass the insertion zone 14 to the holding zone 15 then to the extraction zone 16. As can be seen in Figure 4, the portion of the second lateral face 20 facing 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 passing through the thickness of the rail part 12. Alternatively, the portion of the second lateral face 20 facing the housing 13 could be solid so as to increase the rigidity of the rail part 12 and in particular the rigidity of the holding wall 25.

[0053] The insertion zone 14 comprises a bottom 27 forming a first vertical stop for the lug 10 when the lug 10 is in the insertion zone. The holding zone 15 comprises a bottom 28 forming a second vertical stop for the lug when the lug 10 is in the holding zone. The bottom 28 of the holding zone is positioned below the bottom 27 of the insertion zone. In other words, the bottom of the housing 13 comprises a descending step when it is traveled from the insertion zone 14 to the holding zone 15. A riser 29 thus extends vertically on an edge of the holding zone 15. This riser 29 forms a lateral stop for the lug 10. The riser 29 is positioned substantially under the holding wall 25. The extraction zone 16 comprises a bottom 30 extending at the same level as the bottom 28 of the holding zone.

[0054] To assemble a support 8 to a rail portion 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 portion 12 by moving the support 8 substantially vertically downward. The lug thus passes through the first opening 23 until it comes to bear against the bottom 27 of the insertion zone 14. Then the support 8 is moved horizontally so that the lug 10 slides along the bottom 27 of the insertion zone until it reaches the holding zone 15. During this sliding, the support 8 is slightly raised relative to the lower plate 7 and therefore does not rub against the latter. 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 to bear against the lower plate 7, in particular against the layer of thermally conductive elastic material.The support 8 or the electrochemical cells 4 approach the layer of thermally conductive elastic material by a vertical displacement, which is favorable to the establishment of 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 abutment against the bottom 28 of the holding zone 15 or at a short distance from the bottom 28. The trajectory followed by the lug 10 when the support 8 is placed in the battery pack 3 is illustrated by a first arrow F1 in FIG. 5.

[0055] Once the lug 10 is in the holding zone 15, a lateral movement of the support 8 is blocked by the stop of the lug 10 against the riser 29. An upward movement of the support 8 is limited by the stop of the lug 10 against the holding wall 25. The other potential movements of the support 8 can be blocked or limited for example by a support of the support 8 against an adjacent support or by a complementary fixing means. As a note, in the event that the lower plate 7 is covered with a layer of a thermally conductive elastic material, this can also include an adhesive power forming a complementary fixing means.

[0056] To disassemble a support 8 from a rail portion 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 holding zone until it reaches the extraction zone 16. Once the lug 10 is in the extraction zone, the support 8 is lifted by a substantially vertical upward movement. The lug then leaves the housing 13 through the second opening 24. The path followed by the lug 10 during the extraction of the support 8 in the battery pack 3 is illustrated by a second arrow F2 in FIG. 5. In the event 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.

[0057] As a note, when it is inserted into or extracted from the battery pack, the support 8 is moved in a translational movement. The cooperation which has just been described in relation to the protruding lug from the side 9A of the support can therefore be transposed to the protruding lug 10 from the side 9B of the same support 8. The protruding lugs from the two sides 9A and 9B of the support 8 can therefore be engaged and disengaged simultaneously from their respective housing.

[0058] Finally, each support is thus held at two points thanks to two holding rails extending on either side of the support. In the event that a support has only one lug, the support would only be held at one point. According to another alternative embodiment, the side 9A and / or the side 9B of each support could comprise at least two projecting lugs, each lug cooperating with a housing as described previously. Such a variant makes it possible to further improve the holding of the support 8.

[0059] 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 device for holding the electrochemical cells 4 is simple to manufacture and compact, which leaves a large free volume for the electrochemical cells.

Claims

CLAIMS 1. Battery pack (3) including: - at least one support (8) intended to hold an electrochemical cell (4) or a group of electrochemical cells (4), and - at least one first holding rail (11) capable of holding the at least one support, the first holding rail extending along a first side (9A) of the at least one support, the at least one support comprising a first lug (10) projecting from said first side, the first holding rail comprising a first housing (13) intended to cooperate with the first lug, the first housing comprising an insertion zone (14) for inserting the first lug into the first housing, a holding zone (15) intended to hold the first lug in the first housing, and an extraction zone (16) for extracting the first lug from the first housing.

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

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

4. Battery pack (3) according to one of the preceding claims, characterized in that the at least one first holding rail (11) comprises an upper face (17) comprising a first opening (23), the first lug (10) being intended to pass through the first opening to be inserted into the insertion zone (14), the upper face comprising a second opening (24) separate from the first opening, the first lug (10) being intended to pass through the second opening to be extracted from the extraction zone (16).

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

6. Battery pack (3) according to the preceding claim, characterized in that the casing (5) comprises a lower plate (7) on which the 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 the at least one support and the lower plate.

7. Battery pack (3) according to one of the preceding claims, characterized in that it comprises a second holding rail (11) capable of holding the at least one support (8), the second holding 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 holding rail comprising a second housing (13) intended to cooperate with the second lug, the second housing comprising an insertion zone (14) for inserting the first lug into the second housing, a holding zone (15) intended to hold the second lug in the second housing, and an extraction zone (16) for extracting the second lug from the second housing.

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

9. Method for assembling a battery pack (3) according to one of claims 1 to 7, characterized in that it comprises: - providing at least one support (8) intended to hold 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 holding rail (11) capable of holding the at least one support, the first holding rail comprising a first housing (13) intended to cooperate with the first lug (10), the first housing comprising an insertion zone (14) for inserting the first lug into the first housing, a holding zone (15) intended to hold the first lug in the first housing, and an extraction zone (16) for extracting the first lug from the first housing, then - the insertion of the first lug (10) into the insertion zone (14) of the first housing by a substantially vertical movement of the at least one support, then - the movement of the first lug (10) from the insertion zone (14) to the holding zone (15) of the first housing by a movement substantially horizontal of the at least one support.

10. Method for disassembling a battery pack (3) according to one of claims 1 to 7, characterized in that it comprises: - moving the first lug (10) from the holding zone (15) to the extraction zone (16) of the first housing by a substantially horizontal movement of the 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 movement of the at least one support.

Images