FR2988522A1 - Battery element i.e. battery container, for electric storage unit of electric vehicle, has cells mechanically and electrically connected inside closed container, and ventilation openings allowing circulation of air through cells - Google Patents

Abstract

The element has individual electrochemical cells (129) comprising two opposite ends (1291, 1292). The individual electrochemical cells are mechanically and electrically connected inside a single piece closed container. The cells are fixed to a turntable by the opposite ends according to an arrangement to maintain the turntable around each cell with respect to sufficient air thickness (E129). Ventilation openings (1211, 1212) allow air circulation (R12) through the cells.

Description

The present invention relates to an electric storage battery element and a set of such elements for an electric vehicle, in particular of competition, as well as such a vehicle equipped with a battery. such a set. This element comprises a group of several individual electrochemical cells identical to each other and each having two opposite ends, and which are connected electrically in series and / or in parallel to supply at least one electric propulsion motor. According to the invention, these individual cells are mechanically assembled and electrically connected inside an electrically insulating and dust-tight closed self-supporting container. This container is provided with one or more ventilation apertures and encloses at least a first plate and a second electrically insulating plate substantially parallel to each other, and receiving a circuit for connecting the cells together. These cells are fixed on these plates by their two opposite ends in a determined arrangement to maintain between each cell and its neighbors a sufficient air thickness: on the one hand to satisfy a specific condition of non-arc formation and - on the other hand to allow air circulation between said aeration apertures and through said group of cells. It also relates to such a battery element provided with a common degassing space that can communicate individually with the degassing vents of the different cells.

STATE OF THE ART Motor vehicles with electric propulsion are as old as those with a combustion engine, ie around the end of the 19th century. The industry and the electric vehicle market are currently experiencing significant and growing development, particularly in the last twenty or so years, particularly for reasons of energy and pollution. Electric competition vehicles have existed for such a long time and have provided for example the first vehicle to reach the speed of 100 km / h in 1899. The storage of electricity is a major problem in electric vehicles, inter alia for reasons of safety but also of capacity relative to the weight and the congestion. The traction batteries of small material handling vehicles and the starter batteries of motor vehicles were traditionally lead and acid batteries. For several years now, electric motor vehicles of the road and of competition have adopted batteries of different technologies, which provide a better capacity in relation to their weight and their size, for example lithium-ion batteries, or nickel-ion batteries. hybrid metal or sodium. A vehicle generally comprises a set or "pack" of batteries, which is made from multiple individual electrochemical cells connected together in series and / or in parallel. In the case of lithium-ion technology, these individual cells each provide a voltage of 3.6 V. These individual cells are stacked in a regular shaped plastic container to form a standard module, and several identical modules are assembled from each other. contiguous way to form a complete pack. To maximize performance without compromising vehicle livability, these cells are stacked as compact as possible. These cells are often of elongated cylindrical shape and are stacked parallel to each other in a plastic container forming a module, as described by WO 2011/104792. To improve the compactness and facilitate the evacuation of heat, these cells are now often themselves of a very flattened rectangular shape, sometimes called laminated, and are stacked by their large surface in a module, of which several copies are stacked like blades to form a pack. Such examples are described in documents EP 2 355 201 and WO201199703. This type of batteries gives packs of very compact prismatic shape.

However, such a pack is of a high weight that can create a problem of balancing the vehicle, and may present a tendency to overheat. Coolant piping devices for cooling elements are sometimes provided inside the pack or inside the modules, as described in WO 2011/021843. This cooling circuit however represents additional complexity and risk of leakage, and requires circulation means such as a pump that consume energy and represent additional weight. These types of prismatic arrangements are used in the most recent and fastest vehicles whose performance is similar to that of thermal vehicles of the same categories, for example multipurpose passenger cars such as the "Prius" model of the Toyota company or the road roadster of Tesla brand. More particularly for competition vehicles, the deployment of the first sports electric vehicles, for example of the "Andros Trophy" type, has revealed significant energy needs to guarantee the performance of the vehicle over the entire duration of an event. Thus, for this type of vehicle must be shipped 200 elementary Li-ion cells (type Saft VL41M) to ensure the autonomy of a race of 20 to 25 minutes. With conventional packaging, for example using the plastic containers forming six-cell modules supplied by the company Saft and bringing them together in a metal structure, the total mass is 350 kg, which represents a significant handicap in matter of acceleration, speed and autonomy in the context of an automobile competition. An object of the invention is to improve the performance of electric competition vehicles, speed but possibly also the autonomy, for example by improving the energy / mass ratio of the components. - 4 - Improvements are sought in particular in the very specific field of closed-circuit speed competition over a certain distance or duration of category "Formula" and for example of type "Formula 3".

These improvements are sought in particular on the following points: - stored mass energy; - evacuation of the heat produced; - mechanical resistance ; - resistance to breakdown (ie to arcing); - safety in operation and in case of accident; - ease and cost of manufacture, especially at the unit; - maintenance flexibility; - flexibility of implantation within the vehicle; - Reliability of operation, and homogeneity over the entire speed range and the entire duration of use. The invention proposes a battery cell, said battery tray, electric storage for electric vehicle, in particular competition, comprising a group of several individual electrochemical cells identical to each other and each having two opposite ends, said cells being electrically connected to less in series to power at least one electric propulsion motor. According to the invention, said individual cells are mechanically assembled and electrically connected inside an electrically insulating and dustproof closed self-supporting container. This container is provided with one or more ventilation openings and encloses at least a first plate and a second electrically insulating plate substantially parallel to each other, that is to say making between them an angle of less than 30 ° or even 15 °, and receiving a circuit connecting the cells together. These cells are fixed on these plates by their two opposite ends in a determined arrangement to maintain around each cell, and with respect to its neighbors and said container, a sufficient air thickness: on the one hand to satisfy a determined condition of non-arcing, and secondly to allow air to circulate between said vent openings and through said group of cells. In addition, a set of batteries is provided which comprises at least two battery trays as described herein, which are mechanically independent and connected together to provide a voltage greater than 500 V, and in particular between 560 V and 800 V or between 700 V and 800 V. This total voltage can be for example about 800 V, which allows for example to limit the intensities and therefore the heating and weight of components and electrical circuits. The flexibility of design and realization provided by this architecture also applies to a realization in several separate and autonomous blocks. It is thus possible to distribute the quantity of cells needed in different locations of the vehicle, to optimize for example the size, aerodynamics and weight distribution.

According to another aspect of the invention, there is provided an electric vehicle, in particular closed circuit speed competition, comprising at least one such battery tray. According to a feature, at least two of the battery trays are installed in two separate locations of different shapes, and have different shapes from each other which are adapted to the volumes available in said locations non-interchangeably between them. It is thus possible to distribute the total mass of batteries more flexibly and more efficiently according to criteria specific to the needs of the vehicle.

According to a feature of the invention, the container has a bottom which is surrounded, over its entire periphery by so-called vertical walls transverse to the plates, preferably in a watertight manner. These plates are fixed on said vertical walls in different heights so as to arrange - between - the bottom and the lowest plate a so-called degassing space capable of communicating with a degassing opening carried by one end of the cells, - between the two plates a cooling space communicating with the ventilation openings, and - above the highest plate an accessible space enclosing the cell connecting circuit between them. In addition, the degassing space may be arranged to be airtight in normal use, for example by sealing between the lower plate and the cells, and between the bottom plate and the walls. The degassing space is further arranged to communicate with the degassing vent of each of the individual cells via one (or more) individual orifice which is closed by a fire or protective element, arranged to to open beyond a given heat and / or overpressure from said degassing vent. Thus, in case of degassing of a cell following an individual failure, the degassing space can absorb excess gas, pressure and temperature, without risk to the rest of the cells or the vehicle.

This individual fire-resistant element can be in particular a low mechanical strength seal, for example a tablet of deformable and thermally insulating material such as cardboard sandwiched between two joints carried by the periphery of the end of the cell and the periphery of the housing of the low platinum that encloses this end. It could also be any damper or overpressure firewall of a known type. Such a pellet only yields if it is directly pressurized by the cell it covers. The ends of other cells in good condition are then protected by their own pellet, which receives from the degassing space only a very attenuated overpressure.

In preferred embodiments, the individual cells have an elongated shape along a longitudinal axis, and are arranged parallel to each other and with their longitudinal axis transverse to the plates. In addition, at least two ventilation apertures are provided in container walls substantially transverse to the plates and located at opposite ends of said container, and so as to define an air flow path passing through said container according to a direction substantially parallel to the plates and transverse to the axes of the cells.

Preferably, this circulation path follows a "direct" path, i.e. without loop or return, nor global deviation greater than 90 °. Preferably, at least one battery tray is inserted into the vehicle in a static air cooling circuit (without forced circulation), and has on the one hand at least one ventilation opening provided with a filter against the particles solid and disposed towards the front of the vehicle or confined with a dynamic air inlet, and secondly at least one ventilation opening located towards the rear or the side of the vehicle or closed with a dynamic air outlet .

It should be noted that the mode of implantation of the cells provides a spacing between them which makes it possible to satisfy jointly several types of constraints, whereas it could appear a priori as a disadvantage. Preferably, the cells chosen are of a type without particular external insulation, which saves weight. Such cells have for example metal walls, which are electrically and thermally conductive, or light electrical insulation as a simple varnish. Such light insulation is insufficient to prevent arcing when contact between them at the maximum voltage existing within said battery tray at the maximum voltage of the tray, especially when this voltage is chosen very high. Preferably, such cells are used as such, and are surrounded by no insulating layer other than their outer wall as supplied by the manufacturer, for example a simple liner of a heat-shrinkable material. Most of the electrical insulation between the cells is thus essentially achieved by the air layer due to the spacing of the cells. - 8 - However, this type of insulation requires a larger gap, and therefore a lower compactness than if the cells were embedded or enclosed in housings of insulating material, as is the trend for many existing modules.

By way of example, the manufacturer of Saft cells of the VL41M type for an air layer insulation in a polluted atmosphere recommends a dielectric resistance provided by the formula: withstand (in volts) = 2x voltage (volts) + 2000. maximum of 800 V compared to the vehicle, it is necessary to provide a holding of 3600 V. Such resistance requires a gap of 8 mm in the air, while plastic housings in a container, for example provided by the same manufacturer , allow to be satisfied with a lower thickness of about 5 mm. However, by accepting this larger difference, the invention makes it possible to jointly obtain a lower weight and a greater ease and flexibility in designing and producing the battery pack. In addition, these characteristics are advantageously combined to make it possible to exploit this difference to circulate a cooling current in a simple manner, and in particular by using only few circulation means or not at all. The simplicity and fluidity of the path of the cooling air and its large passage section make it possible to use a dynamic flow naturally created by the speed of the vehicle. Thus, it is even possible to avoid having to implement circulation means such as a cooling turbine.

Optionally, there are external circulators that can be temporarily applied to the air inlets or outlets during stops of the vehicle at the preparation stand. According to another particularity of the invention, the electrical circuit for connecting the cells to one another is carried by the uppermost plate, and is protected by a removable cover covering a part of said upper plate on the whole of said connection circuit. According to yet another particularity of the invention, the space above the upper plate contains all the electrical circuits external to the individual cells within the battery tray, and is external to the individual cells, and is closed. in a waterproof way. Preferably, this seal is made: downwards, for example with respect to splashing from the track in the cooling space, for example by a sealed container and a permanent seal between the plate and the cells and between platinum and walls; and - upwards, for example with respect to the sprinkling by the rain or the fall of the splashing of the track, for example by a seal between the cover and the walls.

The electrical zone is thus located only on the top of the tank. It is both well protected against moisture and remains easily accessible for any intervention. According to the invention, such an element or "battery tray" may have a shape occupying a so-called global volume having on the one hand a so-called main portion having a rectangular section in a specific sectional plane and on the other hand an adjoining portion said additional plane in said section plane outside said rectangular section. For a plan of section parallel to the plates, such a battery can thus have plates whose contour is substantially complementary to the section of said overall volume, said plates supporting individual cells located for some inside said main portion and for others outside of said main portion.

Alternatively or in combination, for a cross-section plane to the plates, such a battery tray may also have plates forming an angle in said section plane so that the ends of the cells that they support occupy a space whose contour is substantially complementary to the lower contour of said overall volume. It can be seen that this architecture makes it possible to design and realize, in a flexible or even unitary manner, battery packs that make the best use of the space available in a vehicle. Within the section of the available volume, for example a horizontal section, it is then simple to bypass the reliefs or to fill the available hollows by distributing the cells inside the outline of the plates, for example according to a distribution. in a grid with a matrix of square "mesh", or with staggered rows in a matrix repeating a substantially hexagonal pattern. This is particularly true in the case of elongated cells, even revolution, and for example cylindrical cells whose two connectors are located at the same end. The design of the vehicle is facilitated, and it is possible to better optimize its layout and the distribution of its masses, within which the batteries represent an important part. This architecture thus makes it possible to satisfy the various technical and safety constraints, while improving the performance, of the vehicle itself, but also the numerous processes that surround it, from design and manufacture to use and maintenance. interview. Thus, in a configuration based on the energy requirements defined for a vehicle of the "Andros Trophy" type, it was possible to reduce the weight of the batteries by 100 kg compared to an initial mass of 350 kg, by making the containers bins of composite material with high resistance. Various embodiments of the invention are provided, integrating, according to all of their possible combinations, the various optional features set forth herein. List of Figures Other features and advantages of the invention will emerge from the detailed description of an embodiment which is in no way limitative, and the attached drawings in which: FIG. 1 is a perspective and transparency diagram of FIG. a "Formula 3" type electric vehicle, illustrating an embodiment of the invention; FIGURE 2 is a perspective diagram showing only the different battery trays in their configuration on the vehicle of FIGURE 1; FIGURE 3 and FIGURE 4 are perspective views, with cover removed and respectively transparent and without connection circuit, of the right front battery tray of the vehicle of FIGURE 1; FIGURE 5 is a perspective view from the rear with covers removed from the central double rear box of the vehicle of FIGURE 1; FIGURE 6 is an exploded view of the right-hand element of the central rear double-bin of the vehicle of FIGURE 1; FIGURE 7 is a sectional side view along AA (see FIGURE 8) illustrating the cell distribution and the architecture of the right front canister of the vehicle of FIGURE 1; and FIGURE 8 is a top view in transparency illustrating the distribution of cells within the right front tray of the vehicle of FIGURE 1.

DESCRIPTION OF AN EMBODIMENT FIG. 1 to FIGURE 8 illustrates a presently preferred embodiment of the invention in a "Formula 3" type closed circuit racing electric vehicle. As illustrated in FIG. 1, the batteries of this vehicle 1 are divided into several blocks or elements each constituting a "battery tray" 11, 12 and 13, each of which is in the form of a closed element, assembled mechanically . Typically, these three bins are mounted in series to provide together the tensile voltage, here 800 V. They each include their own electronic management and monitoring of cells. Two of these so-called simple bins are located on either side of the cockpit, one 12 on the right and the other 13 on the left. At the rear of the cockpit is implanted another bin 11 said double, which has an architecture grouping two subassemblies forming two half-elements 11a and 11b joined back to back. As seen in FIGURE 2 and following, the single bins 12, 13 comprise a container 121, 131 with a bottom 1210 surrounded by so-called vertical walls 1219. This container 121, 131 has an upward opening which is closed by a cover 122, 132. The open container 121, 131 is made watertight or even airtight, for example to prevent water and dust, and the risk of leakage in case of deterioration of their contents. Above the bottom 1210, a degassing space 128 is delimited by a bottom plate 123 which is fixed to the vertical walls 1219, here by external screws cooperating with inserts F12 included in the thickness of the plate in a sealed housing and electrically insulating. A high platen 124 is similarly fixed to the vertical walls 1219 above this low platen 123. The two platens are fixed together by bolting to the two ends of rods 1234 forming both columns and rods, and thus maintain their spacing . The individual cells 129 of the tray 12 are held between these two plates 123 and 124 by their two ends 1291 and 1292 so as to maintain a determined distance between them E29, by insertion into perforations of the plates themselves, or in a perforated grid 1231 and 1241 attached to each plate and surrounding all cell ends. In this embodiment, the cells 129 are of a type grouping its two terminals 1295 on the same end 1291, for example lithium-ion cells with liquid electrolyte type VL41M brand Saft. All the cells 129 have their end 1291 with terminals located on the side of the high platen 124 and whose terminals 1295 pass through the high platen 124. On its face opposite the cells, the high platen 124 carry the connection circuit 125 of the cells together. , or "bus bar" in English. This circuit 125 is thus located in the accessible space 126 of the container 121 after removal of the cover 122, preferably with all or part of the electronics 127 for managing and / or monitoring the cells. All of this circuit 125, 127 is connected to an outlet socket 1278 located outside the tray 12. As seen in FIGURE 7 and FIGURE 8, the two terminals 1295 of each of the cells 129 pass through the high platen 124 by two separate orifices 1249, which each have an elongate shape in a groove in an arc around the axis 1290 of the cell. This elongated shape makes it possible to accept inaccurate angular positions of the cells when they are mounted, when they are all at the same time capped with the upper plate 124. All the terminals can thus be inserted more easily into the orifices 1249. The two orifices 1249 for each cell have different shapes or lengths having a polarity-indicating function. All cells 129 have another end 1292 with a degassing vent 1299 located on the low platen side 123, in communication with the degassing gap 128 through an individual port 1239 for each cell 129.

Normally, this communication port 1293 is obstructed by a cover 1298 of limited resistance to heat and / or pressure, for example a thin plastic or coated cardboard or varnish. In case of overpressure of any cell, which is a safety risk to manage for the lithium-ion technology, the 1299 degassing vent lets out a hot gas and under pressure. The latter opens the lid 1298 and can relax in the degassing space 128. The other lids 1298 isolate the other cells and thus prevent their deterioration. The container 121 (or 111a and / or 111b) has vents 1280 (or 1180) formed by openings cut in its outer wall 1219 and closed by a thin and water-tight membrane, for example Gore-type fabric. Tex. These membranes can give out in case of degassing and the vents then limit the overpressure in the degassing space. The tray 12 has an inlet ventilation opening 1211 and an outlet ventilation opening 1212, here formed in the vertical walls 1219 of the container 121. The inlet opening 1211 is located to receive a pressure of at least one pressure. Positive dynamic air by the speed of the car 1. The outlet opening 1212 is located on the side, preferably in a static or dynamic pressure zone negative or inferior to that of entry. Because of the speed of the vehicle 1, this pressure difference causes an air flow R12 between the inlet opening 1211 and the outlet opening 1212, which passes between the different cells transversely to their longitudinal axis 1290. All the walls of these tanks, ie including the bottom and the lid are made to provide an electrically insulating contact, and are separated from the individual cells and electrical connections of a distance sufficient to meet the protection requirements against arcing for the maximum voltage used.

As can be seen more particularly in FIGURE 7 and FIGURE 8, this architecture allows a great flexibility of implantation of the cells, and to make the most of the space available in the vehicle 1. In side view on FIG. 7 it can be seen that the plates 123 and 124 comprise two substantially flat portions forming between them a slight angle A123 and A124. Since the cells 129 are transverse to the plates, or even perpendicular as in the present case, those situated on these two parts form between them an angle A129 complementary to that A123, A124 of the plates. These angles make it possible to circumvent possible obstacles 10 forming part of the rest of the vehicle, for example a spar 10a or any other part 10b, positioning the cells as low as possible and making the best use of the available volume. Viewed from above in FIGURE 8, it is seen that the majority of the cells 129 are distributed in a contour forming a substantially rectangular region R1240. However, the architecture makes it possible to use some available volumes R1241, R1242 and R1243 outside this main region R1240 to implant additional cells. it may be for example a hollow left by the location of the outer socket 1278; or a narrowing required by a vehicle element such as a post 10c or by the position of an air outlet 1212, for example to abut an outer conduit or to obtain a better depression. Illustrated more particularly in FIGURE 5 and FIGURE 6, the central tray 11 has many points in common with the side bins 12 and 13, and will be described only in its differences. This central tray is formed by several subassemblies, here two half-bins 11a and 12b joined back to back, each having a structure similar to that of a "simple" tray 12 or 13. - 15 - Each half bac lia, lib comprises is accessible by a cover 112a, 112b capping the accessible space 116a of said half tray 11a, and thus defines its so-called "high" region. Each half-tray 11a comprises a ilia container illb bottomless, in which are fixed a "bottom" plate 113a and an "upper" plate 114a, which carries the connecting circuit 115a of cells 119a of the half-tray. These plates tightly enclose the cells through perforated grids 1141a and 1131a. The lower plates 113a of the two half tanks 11a and 10b delimit between them a degassing space 118 common to these two half-tanks, which is facilitated by the fact that only the upper plates 114a carry electrical circuits 115a and 117a. Each half tank accommodates a Rila, Riib cooling air flow between an inlet opening 1111a, illib and an outlet opening 1112a, 1112b. In FIGURE 2, these inlet openings ilia, illb are shown provided with a duct constituting a dynamic inlet mouth or leading to such an inlet mouth, for example a convergent or a NACA outlet. It could be the same for the exit openings.

The container ilia of each half-tank further comprises an internal partial wall 1113a, which obstructs a portion of the passage section of the air stream Riila so as to force it to traverse all the cells 119a, and thus to improve cooling in the parts located away from the direct path between inlet opening 1111a and outlet opening 1112a. The two half tanks lia and lib are contiguous permanently around their common degassing space 118, and are served by the same outlet electrical outlet 1178. In this "double" configuration, the "low" stage 113a of one lia half bins is actually the bottom 30 of the other half bac lib, and vice versa. Of course, the invention is not limited to the examples that have just been described and many adjustments can be made to these examples without departing from the scope of the invention. 35

Claims (10)

REVENDICATIONS1. Battery cell, said battery tray (11, 12, 13), for electric vehicle electrical storage (1) comprising a group of several individual electrochemical cells (119a, 119b, 129, 139) identical to each other and each having two ends (1291, 1292), said cells being electrically connected in series and / or in parallel for supplying at least one electric propulsion motor (19), characterized in that said individual cells are mechanically assembled and electrically connected inside the a closed, electrically insulating and dust-tight container (111a, 111b, 121, 131), which is provided with one or more vent openings (1111a, 1112a, 1211, 1212) and encloses at least a first platen (113a, 123) and a second plate (114a, 124) electrically insulating substantially parallel to each other and receiving a connection circuit (115a, 125) cells between they, said cells being fixed by their two opposite ends to said plates in a determined arrangement to maintain around each cell, and with respect to its neighbors and said container, a sufficient air thickness (E129): - on the one hand to satisfy a predetermined condition of non-arcing, and - secondly to allow air circulation (Rila, R12) between said aeration openings (1111a, 1112a, 1211, 1212) and to through said group of cells (119a, 129). 2. Device according to the preceding claim, characterized in that the container (121, 131) has a bottom (1210) which is surrounded on its entire periphery by walls (1219) said vertical transverse platens (123, 124) , and in that said plates are fixed on said vertical walls in different heights so as to provide: - between the bottom and the lowest plate a so-called degassing space (128) able to communicate with a degassing opening (1298) carried by one end of the cells (129), - between the two plates (123, 124) a cooling space (1230) communicating with the ventilation openings (1211, 1212), and - above the plate the higher an accessible space (126) enclosing the connecting circuit (125) between the cells. 3. Device according to the preceding claim, characterized in that the degassing space (128) is arranged to be airtight in normal use, and communicates with the degassing vent (1298) of each of the individual cells ( 129) via an individual orifice (1239) which is closed by a fire element (1299) arranged to open beyond a determined overpressure from said degassing vent. 4. Device according to any one of the preceding claims, characterized in that on the one hand the individual cells (119a, 129, 139) have an elongated shape along a longitudinal axis (1290), and are arranged parallel to each other and with their transverse longitudinal axis to the plates (113a, 114a, 123, 124), and on the other hand at least two ventilation openings (111a, 1112a, 1211, 1212) are formed in walls (1219) of the container (111a, 121) substantially transverse to said plates and located at opposite ends of said container, and so as to define an air flow path (Rila, R12) passing through said container in a direction substantially parallel to the plates and transverse to the axes of the cells. 5. Device according to any one of the preceding claims, characterized in that it has a shape occupying a so-called global volume having on the one hand a so-called main portion (R1210, R1240) having a rectangular section in a given section plane and on the other hand an additional said adjoining portion (R1211, R1241, -R1242) which protrudes in said section plane outside said rectangular section, and in that: for a section plane parallel to the plates, said battery tray (12) has platens (124) whose contour is substantially complementary to the section of said overall volume, said platens supporting individual cells (129) some located within said main portion (R1240) and for others outside said main portion; and / or for a cross-sectional plane to the plates, said battery tray (12) has plates (123, 124) forming an angle (A123, 124) in said section plane so that the ends of the cells ( 129) that they support occupy a space whose contour is substantially complementary to the lower contour (10) of said global volume. 6. Device according to the preceding claim, characterized in that the space (116a, 126) located above the upper plate (114a, 124) encloses all the electrical circuits (115a, 125, 127) external to the individual cells ( 119a, 119b, 129) within the battery tray (11, 12, 13), and is watertightly closed with respect to the cooling space. 7. A battery pack comprising at least two battery packs according to any of the preceding claims mechanically independent and connected together to provide a voltage greater than 500 V, and in particular between 700 V and 800 V. Electric vehicle (1) comprising at least one battery tray (11, 12, 13) or a battery pack according to any one of the preceding claims. 30 9. Vehicle according to claim 8, characterized in that at least two of the battery trays are installed in two separate locations of different shapes, and have different shapes from each other which are adapted to the volumes. available in said locations non-interchangeably between them. 10. Vehicle (1) according to any one of claims 8 to 9, characterized in that at least one battery tray (11, 12, 13) is inserted in a static air cooling circuit (Rila, R11b, R12), and has on the one hand at least one inlet ventilation opening (1111a, 111b, 1211, 1311) provided with a filter against solid particles and arranged towards the front of the vehicle or closed with an inlet dynamic air, and on the other hand at least one outlet air outlet (1112a, 1112b, 1122) located towards the rear or the side of the vehicle or end with a dynamic air outlet.