Battery pack cell holding frame with cooling

Abstract

The present invention relates to a holding frame (1) for at least one electrochemical cell and intended to be integrated into a battery pack in an electric vehicle, comprising a first half-frame (8a), a second half-frame (8b) and an electrochemical cell, the electrochemical cell being held between the half-frames (8a, 8b), characterized in that at least one recess (14) is formed along at least one of the half-frames (8a, 8b), said recess (14) being intended to be flown through by a cooling fluid for the electrochemical cells.

Description

Description Title of the invention: Battery pack cell holding frame with cooling

[0001] The present invention relates to the field of battery packs for electrically powered vehicles.

[0002] Currently, electric vehicles are equipped with battery packs comprising modules housing electrochemical cells. The number of components arranged within the battery pack is therefore significant, which complicates the integration of the battery pack in a vehicle whose space is increasingly limited. These two constraints are in opposition, which requires finding innovative solutions in the design of this battery pack.

[0003] This battery pack also requires a significant number of parts for the mechanical maintenance and for the cooling of the electrochemical cells it contains, including at least one interlayer, at least one frame and at least one cooling plate, all superimposed and held together, which has the effect of significantly increasing the size of the battery pack in the stacking direction of these elements. Such a battery pack is thus made up of a plurality of assemblies described in document EP2840626.

[0004] Such stacking negatively impacts the integration of the battery pack within the vehicle.

[0005] There is currently a need to improve the configuration of the holding frame and its electrochemical cell cooling system, in order to reduce the dimensions of the battery pack and facilitate its integration into the vehicle.

[0006] The present invention provides a holding frame configured to delimit a channel which conducts a cooling fluid, in order to optimally lower the temperature of the electrochemical cells, while requiring significantly reduced space.

[0007] The main subject of the present invention is thus a holding frame for at least one electrochemical cell and intended to integrate a battery pack of an electrically powered vehicle, comprising a first half-frame, a second half-frame and an electrochemical cell, the electrochemical cell being held between the half-frames, characterized in that at least one clearance is formed along at least one of the half-frames, said clearance being intended to be used by a cooling fluid for the electrochemical cells.

[0008] The assembly of the first half-frame and the second half-frame establishes the architecture of the holding frame for the electrochemical cell. At least one of the half-frames comprises a recess which facilitates the passage of a cooling fluid. dissement, so as to cool the electrochemical cell. The calories generated by this cell are transmitted to the half-frame, then to the cooling fluid which circulates in the clearance. This is how the calories are extracted from the electrochemical cell.

[0009] The holding frame according to the invention thus forms a cooling system and is able to cool the entire electrochemical cell without adding any additional parts, in particular by means of the clearance which is formed at its outer periphery.

[0010] The cooling fluid is preferably air. This airflow enters the vent and approaches the electrochemical cell. In doing so, it collects its calories and transports them outside the battery pack.

[0011] The frame material is preferably a synthetic material, with or without fibers, preferably made from recycled and recyclable material. This material has the advantage of offering a certain freedom in its shape due to the ease of molding complex shapes.

[0012] Alternatively, the frame could also be made of metal, particularly aluminum, if we want to improve their thermal conductivity and therefore the cooling of the electrochemical cells.

[0013] The holding frame, formed by the combination of the first half-frame and the second half-frame, delimits a central area surrounded by branches of this frame. The electrochemical cell is arranged in this central area of ​​the holding frame.

[0014] According to another characteristic of the invention, the two half-frames comprise two longitudinal branches and two lateral branches arranged between the two longitudinal branches, the half-frames comprising at least a first clearance formed on at least one of the longitudinal branches and at least a second clearance formed on at least one of the lateral branches.

[0015] The half-frames and the frame are generally rectangular in shape. At least two intersecting sides of this shape include a clearance. This promotes heat collection by allowing the flow of cooling fluid to circulate on at least two sides of the frame.

[0016] According to another characteristic of the invention, at least one of the clearances is a chamfer formed at an angle of the half-frame. A chamfer is the area which results from a reduction of an empty edge of the half-frame.

[0017] According to another characteristic of the invention, the clearance is formed along a first half-frame and another clearance is formed along the second half-frame, the two clearances at least partially delimiting a channel when the two half-frames are joined to each other.

[0018] The coupling of the first half-frame and the second half-frame is thus configured to form a channel in which the cooling fluid circulates to cool the electrochemical cells, such a channel resulting from the combination of at least two clearances. These two clearances are therefore at least partly opposite each other.

[0019] The channel is any recess, conduit or space along the wall through which a cooling fluid can flow, the cooling fluid advantageously being air.

[0020] By this configuration, the holding frame formed by the association of two half-frames comprises a channel arranged on at least one lateral branch of the frame and a channel arranged on a longitudinal branch of this frame. In this way, the air can circulate as close as possible to the electrochemical cell which is arranged in contact with the holding frame and thus cool the electrochemical cell, on at least two sides thereof.

[0021] Furthermore, this configuration makes it possible to reduce the space to be left between the longitudinal branch of the holding frame and the wall of a housing constituting the battery pack. This channel formed by these two contiguous clearances allows the cooling fluid to circulate, which makes it possible to bring the wall of the housing closer to the holding frame and, ultimately, to reduce a dimension of the battery pack, compared to the prior art. A saving of space in the integration of the battery pack in the vehicle is thus notable.

[0022] According to another characteristic of the invention, at least one clearance comprises cooling fins.

[0023] These cooling fins are arranged within the gap formed in the half-frame. They increase the exchange surface between the cooling fluid, in this case air, and the half-frame. Indeed, the air can lick the cooling fins and get closer to the electrochemical cells, thus lowering their temperature.

[0024] Furthermore, these cooling fins generate turbulence in the circulation of the cooling fluid, which also increases heat exchange. The fins also help reduce the mass of the frames while stiffening them, which allows them to be reinforced while removing material.

[0025] According to another characteristic of the invention, the frame comprises a system for centering the first half-frame with the second half-frame. Advantageously, the electrochemical cell is engaged with the centering system.

[0026] The centering system comprises at least one rib arranged along a longitudinal branch of the first half-frame and on a face thereof which faces the second half-frame. The centering system also comprises at least one groove arranged along a longitudinal branch of the second half-frame and on a face thereof which faces the first half-frame.

[0027] In this way, the rib of the first half-frame fits into the groove of the second half-frame adjacent to the first half-frame in order to form a solid assembly, namely the holding frame.

[0028] The complementary shape between the rib and the groove guarantees good positioning of the first half-frame in relation to the second half-frame, these two elements then being perfectly superimposed.

[0029] According to another characteristic of the invention, at least one of the half-frames comprises at least one ear provided with an orifice intended to receive a member for holding a plurality of frames.

[0030] Such a holding member is, for example, a tie rod whose role is to exert a force on a stack of holding frames. The ear, or plurality of ears, of each half-frame makes it possible to transmit the force from the holding member to the entire half-frame, and thus to ensure that each electrochemical cell is sandwiched between two half-frames of a holding frame according to the invention.

[0031] This holding member, here the tie rod, puts pressure on the stack of holding frames and also the spacers, when the battery pack includes them.

[0032] According to another characteristic of the invention, an interlayer is surrounded by the holding frame and in contact with the electrochemical cell.

[0033] The holding frame prevents the interlayer from moving in order to keep it in contact with the electrochemical cell, this pressure being necessary for the proper functioning of the electrochemical cell to which the interlayer is associated.

[0034] The interlayer is configured to deform according to a dimensional change of the electrochemical cell. In one example, the dimensional change is a change in the thickness of the electrochemical cell.

[0035] Between each electrochemical cell or every n intervals of electrochemical cells, an interlayer is integrated. This interlayer is made of deformable material, advantageously foam or silicone for example, to manage the variations in volume of the electrochemical cells, during the charging or discharging phases of the electrochemical cells, or during the aging of these cells whose volume often tends to increase.

[0036] According to another characteristic of the invention, the electrochemical cell comprises a peripheral edge which surrounds a zone for receiving the electrochemical elements of the electrochemical cell, the peripheral edge being interposed and in contact with the two half-frames.

[0037] When two half-frames are joined together, they pinch the peripheral edge of the electrochemical cell, thus ensuring its mechanical support and the transfer of its calories to the support frame.

[0038] The invention also covers a battery pack for power supply of an electrically powered vehicle comprising at least one housing and a plurality of holding frames according to any one of the preceding claims housed inside the housing, characterized in that a cooling fluid circulates at least in the clearance.

[0039] The cooling fluid is, for example, air. The housing is an envelope that separates an internal volume of the battery pack from the environment surrounding it. The airflow circulates in the housing, along the retaining frames and in at least one clearance, or a channel formed by two contiguous clearances.

[0040] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0041] [Fig- 1] is a perspective representation of a first half-frame and a second half-frame of the holding frame according to the invention;

[0042] [Fig.2] is a sectional representation illustrating the assembly of the half-frames of the [Fig.l] ;

[0043] [Fig.3] is an exploded view representation of a stack of several holding frames according to the invention;

[0044] [Fig.4] is a representation of a plurality of holding frames according to the invention;

[0045] [Fig.5] is a schematic representation of the cooling fluid circuit along the plurality of holding frames according to the invention;

[0046] [Fig.6] is a schematic representation of the cooling fluid circuit according to one variant.

[0047] The features, variants and different embodiments of the invention, as described or as will be presented in the following description, may be combined with each other, in various combinations, to the extent that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0048] As a reminder, the invention proposes a holding frame 1 intended to equip a battery pack of an electrically powered vehicle and in particular making it possible to provide a cooling function for one or more electrochemical cells 2 housed in a housing of the battery pack. This holding frame 1 is particular in that it comprises a channel 4 configured to allow the circulation of a cooling fluid so as to reduce the number of parts usually used for cooling the electrochemical cell 2. Such a holding frame 1 is formed by the junction of two half-frames 8a, 8b, at least one of which includes a clearance 14 which participates in the formation of the channel 4.

[0049] The half-frames 8a, 8b may be structurally identical. In such a case, one of the two half-frames is inverted with respect to the other half-frame, so as to form the holding frame according to the invention.

[0050] [Fig.1] represents on the left a perspective view of a first half-frame 8a and on the right a perspective view of a second half-frame 8b, the assembly of these half-frames forming the frame for holding the electrochemical cell 2.

[0051] As detailed in [Fig.l], each half-frame 8a, 8b comprises two longitudinal branches 10a, 10b and two lateral branches 12a, 12b. The lateral branches 12a, 12b are arranged between the two longitudinal branches 10a, 10b, all of these branches forming a rectangle and delimiting a central zone 11 for receiving the electrochemical cell.

[0052] At least one of the longitudinal branches 10a, 10b and / or the lateral branches 12a, 12b comprises at least one clearance 14, and advantageously several clearances 14 distributed along the branch concerned. In the example illustrated here, each of the longitudinal branches 10a, 10b and each of the lateral branches 12a, 12b comprises one or more clearances 14.

[0053] [Fig.l] also shows the presence of a centering means 13 for centering the first half-frame 8a with the second half-frame 8b. Such a centering means 13 has the role of ensuring the correct positioning of these half-frames 8a, 8b, so that they stack along a rectilinear stacking direction.

[0054] According to an exemplary embodiment illustrated on the left of [Fig.l], the centering means 13 comprises at least one rib 16 formed on at least one of the longitudinal branches 10a, 10b of the first half-frame 8a. The centering means 13 further comprises at least one groove 18 formed in at least one of the longitudinal branches 10a, 10b of the second half-frame 8b, as can be seen in the diagram on the right of [Fig.l].

[0055] In the present case, the centering means 13 comprises in all six ribs 16 and six grooves 18, forming two by two a pair of centering means. This centering means 13 is divided into three ribs 16 and three grooves 18 arranged on each of the longitudinal branches 10a, 10b of each half-frame 8a, 8b.

[0056] It is therefore understood that the ribs 16 arranged on the first half-frame 8a are associated and inserted into the grooves 18 arranged on the second adjacent half-frame 8b, thus constituting the centering means 13 for coupling two half-frames 8a, 8b of the holding frame 1 according to the invention.

[0057] One and / or the other of the half-frames 8a, 8b also comprises at least one ear 20 provided with an orifice 22. In the example of [Fig.l], each half-frame 8a, 8b comprises four ears 22 which project two by two from each lateral branch 12a, 12b of the half-frame.

[0058] The orifice 22 provides a passage for a holding member in order to hold the stack of holding frames 1 together, as illustrated in figures 2, 3 and 4.

[0059] As detailed in [Fig.2], the first half-frame 8a when attached to the second half-frame 8b forms the holding frame 1 according to the invention, as illustrated by the dotted lines in [Fig.2].

[0060] This combination of half-frames creates a channel 4 for the circulation of the cooling fluid. The section of this channel, seen in cross-section, is triangular in shape.

[0061] The holding frame 1 frames the electrochemical cell 2 and an interlayer 26 per electrochemical cell. The interlayer 26 is in contact with one of the large faces of the electrochemical cell 2. The electrochemical cell 2 is in contact with the holding frame 1, its peripheral edge being interposed between the two half-frames 8a, 8b. The holding frame 1 prevents any movement of the interlayer 26, so as to maintain a pressure exerted by the interlayer 26 on the electrochemical cell 2.

[0062] The electrochemical cells 2 are each configured to store or restore electrical energy, necessary for the operation of the electrically powered vehicle with which they are equipped. In one embodiment, the electrochemical cells 2 are lithium-ion battery cells. Of course, other types of battery cells known to those skilled in the art could be used.

[0063] The electrochemical cell 2 comprises a peripheral edge 32 which surrounds a receiving area for the electrochemical elements of the electrochemical cell 2, these elements being the components which store and which restore the electrical energy. The electrochemical cell is a pocket inside which these electrochemical elements are found, such a pocket being joined all around these elements forming the peripheral edge 32.

[0064] As mentioned above, the first half-frame 8a and the second half-frame 8b pinch a peripheral edge 32 which surrounds the electrochemical cell 2. The peripheral edge 32 is defined by thin lateral extensions extending all around the electrochemical cell 2. The peripheral edge 32, once inserted and pinched by the half-frames, securely holds the electrochemical cell 2 within the holding frame 1 according to the invention.

[0065] As detailed in Figures 3 and 4, two electrochemical cells 2 immediately adjacent to each other are electrically connected by a connection member 34, which ensures electrical series or parallel connection of these electrochemical cells 2. Such a connection member takes the form of an electrical strip electrically conductive. Two electrical poles of electrochemical cells could also be connected together directly, without using a connecting member.

[0066] As detailed in [Fig.4], channels 4 are formed on an upper part 36 and on a lower part 38 of the holding frame 1, as well as on two lateral parts, namely a first lateral part 40 and a second lateral part 42 arranged on either side of the holding frame 1.

[0067] The upper part 36 and the lower part 38 of the holding frame 1 are each formed by the juxtaposition of the longitudinal branches of the two half-frames 8a, 8b which form the holding frame 1. The same applies to the first lateral part 40 and the second lateral part 42 which result from the juxtaposition of the lateral branches of the half-frames 8a, 8b. The holding frame 1 according to the invention thus at least partially delimits longitudinal channels 4 and lateral channels 4.

[0068] The upper part 36 is arranged opposite an upper wall of a housing constituting the battery pack and the lower part 38 is arranged opposite a lower wall of this same housing.

[0069] The cooling fluid represented by arrows in [Fig.4] can thus circulate within these different channels 4 for the cooling of the electrochemical cells 2.

[0070] As seen in Figures 1 to 4, the channels 4 include cooling fins 44, configured to transfer thermal energy from the electrochemical cells 2 to the cooling fluid flowing in the clearance 14, along the cooling fin 44.

[0071] A cooling fin 44 takes the form of a flat flank that extends within a clearance 14 of at least one of the half-frames 8a, 8b. The cooling fin 44, or the plurality of cooling fins 44, disturbs the flow of the cooling fluid. In doing so, the amount of heat transferred from the holding frame 1 according to the invention to the cooling fluid is greater. The fins also help to reduce the mass of the holding frames 1 by stiffening them, requiring less material to be used for their manufacture.

[0072] The cooling fluid can thus perform its function as close as possible to the electrochemical cells 2 with improved cooling efficiency.

[0073] As detailed in [Fig. 5], the cooling fluid arrives simultaneously on the two lateral parts 40, 42 of the holding frames 1, ensuring on this occasion the cooling of the electrical connection poles of the electrochemical cells 2, or the connection members 34, in the first place. This cooling of the electrical poles or the connection members is particularly interesting because of the high heat emitted by the latter and transmitted to the electrochemical cells 2. The cooling fluid arriving on the two lateral parts 40, 42 is the coolest, which prevents these calories from being transmitted to the electrochemical cell, as such. Furthermore, the air flow, by its impact, generates turbulence, which provides efficient cooling. The cooling fluid changes direction substantially in the center of the holding frames 1, according to their longitudinal direction. Before this change of direction, the cooling fluid circulates in the channels 4 of the plurality of holding frames 1. In this way, the cooling fluid circulates in the channels 4 then circulates perpendicular to the longitudinal branches 10a, 10b of the holding frames 1 towards an extraction zone 46 of the battery pack.

[0074] As detailed in [Fig.6], it is also possible to alternatively design that the cooling fluid arrives at one of the lateral parts 40 of one or more holding frames 1, then travels through the lateral channels 4, then the longitudinal channels 4 of the holding frame 1. After having licked the other lateral part of the holding frame 1 while circulating in the lateral channels 4, the cooling fluid is extracted by an extraction zone 46.

[0075] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0076] The invention, as just described, achieves the goal it set itself, and makes it possible to propose a holding frame which is optimized and more compact compared to the holding frames currently used to provide a cooling function for electrochemical cells.

[0077] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

Claims

Claims

1. Holding frame (1) for at least one electrochemical cell (2) and intended to integrate a battery pack of an electrically powered vehicle, comprising a first half-frame (8a), a second half-frame (8b) and an electrochemical cell (2), the electrochemical cell (2) being held between the half-frames (8a, 8b), characterized in that at least one clearance (14) is formed along at least one of the half-frames (8a, 8b), said clearance (14) being intended to be used by a cooling fluid for the electrochemical cells (2).

2. Holding frame (1) according to the preceding claim, characterized in that the two half-frames (8a, 8b) comprise two longitudinal branches (10a, 10b) and two lateral branches (12a, 12b) arranged between the two longitudinal branches (10a, 10b), the half-frames (8a, 8b) comprising at least one clearance (14) formed on at least one of the longitudinal branches (10a, 10b) and at least one clearance (14) formed on at least one of the lateral branches (12a, 12b).

3. Holding frame (1) according to any one of the preceding claims, characterized in that at least one of the clearances (14) is a chamfer formed at an angle of the half-frame (8a, 8b).

4. Holding frame (1) according to any one of the preceding claims, in which the clearance (14) is formed along the first half-frame (8a) and another clearance (14) is formed along the second half-frame (8b), the two clearances (14) at least partially delimiting a channel (4) when the two half-frames (8a, 8b) are joined to each other.

5. Holding frame (1) according to any one of the preceding claims, characterized in that at least one clearance (14) comprises cooling fins (38).

6. Holding frame (1) according to any one of the preceding claims, comprising a centering system (13) of the first half-frame (8a) with the second half-frame (8b).

7. Holding frame (1) according to any one of the preceding claims, characterized in that at least one of the half-frames (8a, 8b) comprises at least one ear (20) provided with an orifice (22) intended to receive a holding member of a plurality of holding frames

8. Holding frame (1) according to any one of the preceding claims, comprising an interlayer (26) surrounded by the holding frame (1) and in contact with the electrochemical cell (2).

9. Holding frame (1) according to any one of the preceding claims, characterized in that the electrochemical cell (2) comprises a peripheral edge (32) which surrounds a zone for receiving the electrochemical elements of the electrochemical cell (2), the peripheral edge (32) being interposed and in contact with the two half-frames (8a, 8b).

10. Battery pack for the electrical supply of an electrically powered vehicle comprising at least one housing and a plurality of holding frames (1) according to any one of the preceding claims housed inside the housing, characterized in that a cooling fluid circulates at least in the clearance (14).

Images