Energy storage device for a vehicle comprising a tank and an electrochemical battery

Abstract

Energy storage device for a vehicle comprising a tank and an electrochemical battery Energy storage device (2) for a motor vehicle (1), comprising: - a set of electrochemical cells (21), - a tank (3, 3') intended to store an energy fluid, and - a casing (30) intended to be fixed to a chassis (31) of the vehicle, the casing supporting the set of electrochemical cells and the tank. Figure for the abstract: figure 2

Description

Title of the invention: Energy storage device for a vehicle comprising a tank and an electrochemical battery Technical field of the invention

[0001] The invention relates to an energy storage device for a vehicle comprising a tank intended to store an energy fluid, in particular hydrogen, and an electrochemical battery. The invention also relates to a vehicle, in particular a motor vehicle, comprising such an energy storage device. State of the prior art

[0002] In order to make the use of vehicles less polluting, vehicles are known that are equipped with a fuel cell powered by hydrogen. These vehicles therefore have a tank in which hydrogen is stored before being consumed by the fuel cell. The fuel cell provides electrical energy that can be consumed directly by an electric motor to move the vehicle forward, or stored in an electrochemical battery on board the vehicle. The electrochemical battery can therefore be recharged using the fuel cell. In addition, the electrochemical battery can also be configured to be recharged via an electricity distribution network. Such vehicles comprise two energy storage means formed on the one hand by the hydrogen tank, and on the other hand by the electrochemical battery.

[0003] The pressure of the hydrogen in the tank can be very high, for example of the order of 700 Bar. The tank must therefore be particularly resistant to the mechanical stresses exerted by pressurized hydrogen. In addition, hydrogen is a highly flammable gas which causes fire risks in the event of a leak. Hydrogen tanks must therefore also be shock-resistant, so as to guarantee the safety of passengers in the event of a vehicle accident. Tanks known from the state of the art generally take the form of one or more cylinders on board the vehicle. Such cylinders are particularly bulky and complex to integrate within the vehicle.

[0004] On the other hand, electrochemical batteries intended to power an electric motor are also dangerous energy reserves. In the event of damage, they can ignite and / or cause electrification or electrocution. An electrochemical battery conventionally comprises a set of electrochemical cells arranged in a casing supporting and protecting the electrochemical cells from the external environment. The casing protects the other components of the vehicle from any risk of contact with electrical conductors of the electrochemical battery and prevents the escape of gases in the event of a malfunction of an electrochemical cell. An electrochemical battery is also a very large and complex device to integrate within the vehicle. The electrochemical battery generally extends to the level of a floor of the vehicle.

[0005] Thus, the vehicles known from the state of the art which comprise both a reservoir for an energy fluid and an electrochemical battery to power an electric motor present a poor compromise between autonomy, space available for passengers or for storing objects, and size of the vehicle. Presentation of the invention

[0006] The aim of the invention is to provide an energy storage device for a vehicle which overcomes the above drawbacks and improves the energy storage devices known from the prior art.

[0007] More specifically, a first object of the invention is to provide an energy storage device comprising a reservoir and an electrochemical battery which is compact and which offers optimum safety for users of the vehicle. Summary of the invention

[0008] The invention relates to an energy storage device for a motor vehicle, the energy storage device comprising: - a set of electrochemical cells, - a reservoir intended to store an energy fluid, and - a casing intended to be fixed to a vehicle chassis, the casing supporting all of the electrochemical cells and the tank.

[0009] The housing may include a frame extending laterally around the electrochemical cells and the reservoir.

[0010] The frame can be formed by a series of profiled elements fixed, in particular welded, one after the other.

[0011] The casing may further comprise: - suitable mounting brackets for fixing the energy storage device to the vehicle chassis, and / or - shock absorbers capable of absorbing the energy of an impact in the event of the vehicle colliding with an obstacle.

[0012] The reservoir may comprise a collar at least partially surrounding the reservoir, and the reservoir may be secured to the casing via its collar.

[0013] The reservoir may comprise a rigid structure made of a composite material, and the collar may be anchored in the composite material.

[0014] The reservoir may comprise at least a first pair of connected opposing walls to each other by a first set of connecting elements, passing through the tank and extending parallel to a first axis, the tank comprising at least one fixing interface arranged at one end of at least one connecting element, the collar being fixed to the tank via the at least one fixing interface.

[0015] The collar may be fixed against an upper face of the frame or against a lower face of the frame.

[0016] The invention also relates to a vehicle, in particular a motor vehicle, comprising a chassis and an energy storage device as defined previously, the casing of the energy storage device being fixed to the chassis.

[0017] The invention also relates to a method for designing an energy storage device as defined above, the method comprising: - the identification of an existing energy storage device comprising a housing and a set of electrochemical cells supported by said housing, then - the removal of a part of the electrochemical cells from said set of electrochemical cells, then - the design of a reservoir intended to store an energy fluid, the reservoir comprising a geometric shape adapted so that the reservoir occupies the space freed up by the removal of said part of the electrochemical cells. Presentation of figures

[0018] 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:

[0019] [Fig.l] is a schematic side view of a motor vehicle equipped with an energy storage device according to one embodiment of the invention.

[0020] [Fig.2] is a perspective view of a first embodiment of a reservoir of the energy storage device.

[0021] [Fig. 3] is a partial perspective view of the tank according to the first embodiment.

[0022] [Fig.4] is a partial and transparent view of the tank according to the first embodiment.

[0023] [Fig.5] is a sectional view of a tank attachment interface according to the first embodiment.

[0024] [Fig.6] is a perspective view of a second embodiment of a reservoir of the energy storage device.

[0025] [Fig.7] is a perspective view of an energy storage device according to one embodiment of the invention.

[0026] [Fig.8] is a top perspective view of the energy storage device of [Fig.7] with a reservoir of the energy storage device obscured.

[0027] [Fig.9] is a bottom perspective view of the energy storage device of [Fig.7], with the reservoir of the energy storage device hidden.

[0028] [Fig. 10] is a side view of the energy storage device of [Fig.7]. Detailed description

[0029] [Fig.l] schematically illustrates a motor vehicle 1 according to one embodiment of the invention. The vehicle 1 may be, for example, a private vehicle or a utility vehicle. Alternatively, it could be a truck, a bus, a lifting machine, an agricultural machine or even any other type of land vehicle. The invention may also be adapted to an aircraft or a boat.

[0030] In this document, the X axis designates the longitudinal axis of the vehicle 1. When moving forward and in a straight line, the vehicle 1 moves from the rear to the front in a direction parallel to its longitudinal axis. The X axis is oriented from the front to the rear of the vehicle, that is to say in the direction of reverse travel. The Y axis designates the transverse axis of the vehicle. The Y axis is oriented from left to right, left and right being defined according to the point of view of a driver of the vehicle 1. The Z axis designates the axis perpendicular to the X axis and the Y axis. It is considered that the vehicle 1 is resting on horizontal ground. The Z axis is a vertical axis, oriented from bottom to top. The X, Y and Z axes form an orthogonal reference frame. This reference defined in relation to the vehicle 1 may be used to describe an energy storage device 2 of the vehicle 1, even considered outside the vehicle, since the tank is intended to be integrated into the vehicle in a particular orientation..

[0031] The vehicle 1 is equipped with an energy storage device 2 according to one embodiment of the invention. The energy storage device 2 comprises a tank 3, 3' and an electrochemical battery 4. The vehicle 1 also comprises a fuel cell 5 capable of transforming hydrogen into an electric current, and an electric motor 6 powered by an electric current from the fuel cell 5. The electric motor 6 is configured to drive drive wheels of the vehicle 1. The vehicle 1 further comprises a chassis 31 supporting, among other things, the energy storage device 2, the fuel cell 5 and the electric motor 6.

[0032] Figures 2 and 6 respectively illustrate a first embodiment of the reservoir 3 and a second embodiment of the reservoir 3'. Where possible, the same references are used to describe the same characteristics of the reservoir 3 and the reservoir 3'.

[0033] According to the illustrated embodiments, the reservoir 3, 3' is intended to store hydrogen or more precisely dihydrogen. According to other variants, the reservoir 3, 3' could be configured to store other forms of energy gases, for example liquefied petroleum gas or natural gas. The tank could even be intended to store a liquid fuel such as gasoline, diesel or even ethanol. In such a case, the vehicle could include a combustion engine capable of transforming the energy of the energy fluid into electromotive force.

[0034] Generally speaking, the tank 3, 3' is intended to contain an energy fluid, that is to say a fluid forming a reserve of fluid energy, convertible into an electromotive force capable of moving the vehicle. The tank is therefore a component of the vehicle 1 which gives it a certain autonomy. The tank comprises in particular an inlet opening allowing the tank to be filled with an energy fluid and an outlet opening for delivering and then consuming the energy fluid contained in the tank.

[0035] The tank 3, 3' is intended to store the energy fluid under pressure, that is to say at a pressure strictly higher than atmospheric pressure. In this case, the tank is intended to store the energy fluid, in particular hydrogen, at a pressure greater than or equal to 700 Bar. Alternatively, the tank could be intended to store the energy fluid at a different pressure, for example a pressure greater than or equal to 300 Bar, or 500 Bar, or 1000 Bar, or any other value. The tank thus comprises a rigid structure capable of withstanding the forces exerted by the pressurized fluid that it contains, that is to say centrifugal forces acting from inside the tank and which tend to cause it to burst.

[0036] Furthermore, the tank 3, 3' may have a capacity greater than or equal to 50 liters, preferably greater than or equal to 100 liters, or even greater than or equal to 150 liters. A 100-liter tank makes it possible to store approximately 4 kg of hydrogen at 700 Bar, which gives a motor vehicle a range of around 300 km.

[0037] The structure of the tank 3, 3' is also capable of withstanding significant impacts, in particular impacts occurring in the event of an accident of the vehicle 1, without generating any leakage of the energy fluid to the outside. Accident data and / or simulations and / or crash tests make it possible to size the structure, in particular the required wall thicknesses, so that no leakage of energy fluid occurs, even for the most violent accidents.

[0038] Advantageously, the reservoir 3,3', the high strength of which is necessary to withstand high pressures of the energy fluid it contains as well as to guarantee the safety of the passengers of the vehicle 1 in the event of an accident, can be used to stiffen the energy storage device 2, and more generally to stiffen the structure of the vehicle. The reservoir is capable of supporting the weight exerted by other equipment of the vehicle, and also provides a support for fixing these equipment.

[0039] The tank 3, 3' is capable of supporting loads that can reach at least one hundred kilograms, or even several hundred kilograms. These loads can be static loads such as those exerted by the weight of equipment such as vehicle seats and / or the weight of the vehicle's passengers. These loads can also be dynamic loads such as those that appear in particular situations such as during an impact against the vehicle. These different static or dynamic loads can exert compressive or shear forces on the tank. These forces are therefore oriented in a different direction from the centrifugal forces exerted by the pressurized energy fluid inside the tank.Advantageously, the resistance of the reservoir necessary to resist the pressure exerted by the energy fluid it contains is therefore also used to support loads which are exerted in different directions.

[0040] The tank 3, 3' referred to in the invention is typically a polymorphic structural tank made of composite materials using a weaving process similar to that presented in document FR 2888915Al. This tank comprises internal reinforcement wells which pass through the interior volume of the tank and which connect two by two of the opposite walls of the tank 3 so as to secure them together. This structure and this arrangement ensure mechanical support of the tank suitable for receiving high-pressure gases, in particular for containing hydrogen. The tank being rigid, it is therefore used as a structural element of the vehicle, in addition to the conventional structural elements of the underbody of the vehicle.

[0041] The reservoir 3, 3' typically comprises a roughly parallelepiped shape. In this embodiment, it comprises three pairs of opposite walls. A first pair of opposite walls is composed of a front wall 7A and a rear wall 7B. The walls 7A and 7B extend substantially parallel to the Y and Z axes. A second pair of opposite walls is composed of a left side wall 8A and a right side wall 8B. The walls 8A and 8B extend substantially parallel to the X and Z axes. A third pair of opposite walls is composed of an upper wall 9A and a lower wall 9B. The walls 9A and 9B extend substantially parallel to the X and Y axes. Alternatively, any other shape of the reservoir could be envisaged.

[0042] The tank 3, 3' is arranged in the rear part of the vehicle 1, in particular at the level of a rear part of a base of the vehicle. The tank 3, 3' extends in particular under a row of rear seats of the vehicle and / or under a trunk of the vehicle, or even up to the level of a rear bumper of the vehicle. The tank can thus be intended to support the load exerted by the rear seats and all of the objects stored in the trunk of the vehicle.

[0043] The upper wall 9A may comprise recesses 10 intended to receive the seat base of the vehicle, so that the passengers seated on these seats are not installed too high. Between the recesses 10, the upper wall 9A comprises a projecting central rib 11 which makes it possible to increase the volume of the tank without penalizing the comfort of the passengers installed on the seats above the tank.

[0044] Advantageously, the tank 3, 3' also comprises an anti-submarining device 12. Such a device forms a stop preventing the seating of the seats above the tank from sliding forward in the event of an accident. The anti-submarining device 12 is formed by a protrusion extending forward and upward in front of the recesses 10. The anti-submarining device 12 may comprise a profiled shape along the Y axis and / or extend over the entire width of the tank along the Y axis. In addition to improving passenger safety, the integration of the anti-submarining device 12 into the tank makes it possible to increase the volume of the tank and therefore to increase its energy fluid storage capacity.

[0045] The tank 3, 3' may be isolated from the passenger compartment by a simple protective element, for example made of plastic, which covers the tank. No structural element must be integrated between the tank 3, 3' and the vehicle seats above the tank since the latter has sufficient strength to support the weight of the seats and the passengers seated on these seats.

[0046] The tank 3, 3' may also provide a support for attaching a safety device. The safety device is intended to protect the passengers of the vehicle in the event of an accident. In particular, the safety device may comprise a seat belt and / or a device according to ISO 13216-1:1999, more commonly referred to as the "Isofix" system. These safety devices may be attached to the upper wall 9A of the tank.

[0047] Advantageously, the structure of the tank 3, 3' is made of composite material. Such a material is lighter than steel and even than any other metal for equivalent strength. In addition, the methods for manufacturing components made of composite material make it possible to produce structures with a wide variety of geometric shapes. More complex structural shapes than those obtained in metal can thus be envisaged so as to exploit all available volume of the vehicle and thus increase the capacity of the tank. More complex tank shapes can in particular be recommended when the tanks are intended to store a gas under pressure rather than a liquid because, unlike a liquid, the gas does not present a risk of retention in the tank.

[0048] The composite material may comprise a draped or preformed structure, and / or woven and / or braided materials impregnated with resin. The composite material may be consisting of reinforcing elements and a matrix. The reinforcing elements may include carbon or glass fibers, which are lightweight materials, or Kevlar (registered trademark), which has greater impact resistance. The matrix may be an organic matrix, for example, epoxy resin, phenolic resin, or a modified polyester. The matrix may also be a metal matrix.

[0049] Figures 3 and 4 illustrate in perspective view the structure of the tank 3 according to the first embodiment. The walls 7A and 7B are connected to each other by a first set of connecting elements 51 extending parallel to the X axis. These connecting elements form internal wells passing through the interior volume of the tank and securing two opposite walls to each other and working essentially in traction so as to stiffen the structure of the tank. Similarly, the walls 8A and 8B are connected to each other by a second set of connecting elements 52 extending parallel to the Y axis and the walls 9A and 9B are connected to each other by a third set of connecting elements 53 extending parallel to the Z axis.

[0050] According to an alternative embodiment, the tank 3 could comprise only one set of connecting elements or only two sets of connecting elements among the three sets of connecting elements 51, 52, 53. Alternatively, all or part of the sets of connecting elements 51, 52, 53 could extend in directions different from the X, Y and Z axes, provided that the axis along which each of the sets of connecting elements extends forms a non-zero angle with the axis along which the other sets of connecting elements extend. Advantageously, the three axes along which the three sets of connecting elements 51, 52 and 53 extend are perpendicular to each other so as to stiffen the tank optimally.

[0051] The connecting elements 51, 52, 53 pass through the tank 3 from one side to the other between two opposite walls. The connecting elements act as tie rods reinforcing the resistance of the tank: they are subjected to tensile stress when the energy fluid contained in the tank exerts pressure on the walls 7A, 7B, 8A, 8B, 9A, 9B. The connecting elements 51, 52, 53 are arranged inside the casing of the tank 3 and not on the periphery of this casing.

[0052] Preferably, each connecting element 51, 52, 53 is distinct from the other connecting elements, that is to say that the connecting elements 51, 52, 53 are without contact with each other and do not touch each other inside the tank. Thus, the tank 3 is not compartmentalized and the energy fluid can circulate easily inside the tank 3.

[0053] The connecting elements 51, 52, 53 are hollow. In particular, the connecting elements, which could also be called "reinforcement wells", may be tubes when they have a circular section. However, the section of the connecting elements is not necessarily circular. For example, the section of the connecting elements could also be square, rectangular, polygonal or ovoid.

[0054] [Fig. 5] illustrates in more detail a connecting element 51, the other connecting elements being designed in a similar manner. Each connecting element 51, 52, 53 comprises a tubular shape provided with an external face 54 and an internal face 55. The external face 54 is turned towards the inside of the tank and is therefore intended to be in contact with the energy fluid, while the internal face 55 communicates with the outside of the tank and is therefore intended to be in contact with the ambient air.

[0055] The connecting elements 51, 52, 53 may be made of composite material or metal. They may also comprise both a composite material and metal. In particular, they may comprise a metal tube arranged inside a structure made of composite material.

[0056] The internal face 55 may be provided in a material different from that forming the structure of the tank. The internal face 55 may in particular be equipped with a metal tube which extends over the entire length of the connecting element 51, 52, 53 or only at the ends of the connecting elements 51, 52, 53. The metal tube may optionally be ringed on its outer periphery so as to guarantee good support in the structure.

[0057] Each connecting element 51, 52, 53 comprises two opposite ends at the level of the two opposite walls that it connects. Due to the hollow nature of the connecting elements 51, 52, 53, the tank 3 comprises, for each connecting element, an opening 56 passing right through the tank. These openings 56 do not communicate with the energy fluid storage volume. These openings 56 are therefore not useful for delivering an energy fluid, in particular for delivering pressurized hydrogen to the fuel cell 5.

[0058] On the other hand, the openings 56 can be used for the passage of electrical wires and / or hydraulic conduits. It is thus possible to save the space provided outside the tank for the passage of these electrical wires and / or these hydraulic conduits while providing them with a means of holding them in position. The openings 56 can also be used to allow the evacuation of a liquid from the vehicle, or even to create vents intended to cool or heat the passenger compartment. The openings 56 can also be used to fix various pieces of equipment of the vehicle.

[0059] For this purpose, the tank 3 may comprise a set of fixing interfaces 57, each arranged at one end of at least one connecting element 51, 52, 53, in particular arranged in one end of an opening 56. As illustrated in [Fig. 5], all or part of the fixing interfaces 57 may comprise an insert intended to cooperate with a fixing screw 58, for example a fixing screw of type M8 or M10. The insert may be formed in the metal tube equipping the internal face 55 of the connecting elements or be an additional element fitted against the internal face 55 of the connecting elements, for example a plastic dowel. The insert may for example have a length between 20mm and 60mm inclusive. The insert may be threaded or unthreaded. The insert thus provides a means of fixing extending deep into the volume of the tank. Such a means of fixing is particularly robust and makes it possible to envisage the fixing of heavy loads.

[0060] Each fixing interface 57 makes it possible to fix a piece of equipment of the vehicle against a wall of the tank 3. A fixing interface 57 can be arranged at the end of the opening 56 located on the side of the wall against which the equipment is fixed. Alternatively, a fixing interface 57 could also be arranged at the end of the opening 56 located on the opposite side of the wall against which the equipment is fixed. In this case, an axis or a cable connecting the fixing interface 57 to the equipment could extend inside the opening 56 along the latter. Such an arrangement would for example make it possible to provide fixing interfaces at the level of the lower wall 9B to fix equipment against the upper wall 9A, which would facilitate vehicle assembly or maintenance operations.

[0061] Advantageously, such fixing interfaces 57 can be provided at the ends of each opening 56 of the tank 3. Each connecting element 51, 52, 53 can thus support two fixing interfaces 57 arranged on two opposite faces of the tank. The tank can thus be provided with a multitude of fixing interfaces 57 making it possible to fix various equipment in very varied positions.

[0062] The same equipment can even be fixed to the tank 3 using two or more fixing interfaces, so as to secure its fixing. The same equipment can also easily be fixed in different positions of the tank, without having to be modified.

[0063] The same tank 3 can also be easily reused for different vehicle models because the multitude of fixing interfaces provides numerous possibilities for fixing equipment.

[0064] The openings 56 which are not intended to fix equipment of the vehicle can be plugged with a sealing means so as to avoid the accumulation of mud, sand, earth, stones or any other particles. In particular, the unused openings 56 can be plugged with individual plugs or with a film surrounding the entire tank or any other protective device. The unused openings 56 can possibly be used during the life of the vehicle for example to fix new equipment or a new accessory.

[0065] Advantageously, the connecting elements 51, 52, 53 are distributed according to a regular pitch, for example a pitch between 5 cm and 30 cm inclusive, in particular between 10 cm and 20 cm inclusive. Consequently, the fixing interfaces 57 are distributed on the walls of the tank at a regular pitch. The fixing interfaces 57 are thus arranged according to a grid on the surface of the tank 3. This further facilitates the reuse of the same tank and the same equipment for different vehicle models because this same equipment can be fixed in several places on the tank without requiring an adaptation part. The tank thus forms a modular structure, on which numerous pieces of equipment can be fixed. The invention therefore makes it possible to envisage great freedom of design of motor vehicles while achieving economies of scale.

[0066] According to the second embodiment, the reservoir 3' is devoid of connecting elements as described previously. The resistance of the reservoir 3' can then be provided by the thickness of its walls, and possibly by the addition of other reinforcing inserts.

[0067] Generally speaking, the reservoir 3, 3' is positioned at the rear of the electrochemical battery 4. The front wall 7A of the reservoir faces the rear wall of the electrochemical battery 4

[0068] The electrochemical battery 4 can be configured to deliver a direct electric current whose voltage is approximately equal to 400V, or possibly 800V. The electrochemical battery 4 can be recharged by an electric current from the fuel cell 5 and / or by a connection to an electricity distribution network. The electric motor 6 can thus be supplied with energy by an electric current from the electrochemical battery 4. The tank 3, 3' associated with the fuel cell 5 can thus act as a range extender for the vehicle, when the electrochemical battery 4 is discharged.

[0069] The electrochemical battery 4 comprises a set of electrochemical cells 21, for example of the lithium-ion type. The electrochemical cells 21 are electrically connected to each other, for example in series and / or in parallel. The electrochemical cells 21 can be grouped into electrochemical modules. Each electrochemical module thus comprises several electrochemical cells 21. The electrochemical battery 4 can comprise, for example, between two and twenty electrochemical modules. The electrochemical modules are preferably distributed on the same level. The electrochemical battery 4 thus has a height along the Z axis which is relatively restricted, which makes it possible to integrate the electrochemical battery 4 into the underbody of the vehicle. The electrochemical modules can be separated from each other by partition walls. The electrochemical battery 4 also comprises a cooling device.The cooling device may comprise a cooling plate, which extends under the electrochemical modules to cool them. Finally, the electrochemical battery 4 may also comprise an electronic controller and electrical conductors, in particular for . connect the electrochemical battery 4 to the electric motor 6.

[0070] The various components of an electrochemical battery 4 are conventionally supported by a casing. According to the invention, and as is also shown in FIGS. 7 to 10, the casing usually used to hold the electrochemical cells 21 is used to also support the reservoir 3, 3' described previously. Consequently, the reservoir 3, 3' can be integrated in place of a portion of the electrochemical cells 21. The energy storage device 2 therefore comprises a casing 30 supporting all of the electrochemical cells 21, as well as the reservoir 3, 3'. The casing 30 is fixed to the chassis 31 of the vehicle.

[0071] The chassis 31 is a part of the vehicle body, that is to say a rigid structure, preferably made of steel, which supports all of the vehicle's components, including the fuel cell 5, the electric motor 6, but also a passenger compartment, a body or even a running gear of the vehicle.

[0072] More specifically, the casing 30 comprises a frame 32 extending laterally around the electrochemical cells 21 and the reservoir 3, 3'. The frame 32 thus forms a belt which surrounds the electrochemical cells 21 and the reservoir 3, 3' at the front, at the rear, and along their right and left sides.

[0073] The casing 30 is fixed to the chassis 31 by means of the frame 32. For this purpose, the casing 30 comprises fixing lugs 33 distributed around the frame 32. The fixing lugs 33 may comprise holes cooperating with fixing screws. The fixing lugs 33 may be welded to the frame 32.

[0074] The casing 30 also comprises a lower plate 34 fixed to the frame 32. The lower plate 34 supports all of the electrochemical cells 21. The lower plate 34 extends substantially horizontally under the electrochemical cells 21 and is preferably made of metal, for example aluminum. The cooling plate previously described preferably extends between the lower plate 34 and the electrochemical cells 21. The lower plate 34 protects the electrochemical cells from impacts and / or projections oriented from the bottom to the top. It also protects the electrical conductors of the electrochemical battery from any unwanted contact. As can be seen in [Fig. 9], the lower plate 34 does not extend under the reservoir 3, 3'. Indeed, the reservoir 3, 3' already comprises a sealed and impact-resistant casing.The dimensions of the lower plate 34 may therefore be limited to the dimensions of the volume occupied by the electrochemical cells 21. The reservoir 3, 3' may nevertheless be protected against abrasion by a lighter protective element, for example a plastic plate. The lower wall 9B of the reservoir 3, 3' may extend lower than the lower plate 34 so as to increase the capacity of the reservoir.

[0075] The housing 30 also includes an upper plate 35 fixed to the frame 32. The upper plate 35 extends substantially horizontally above the electrochemical cells 21 and is preferably made of metal, for example aluminum. The upper plate 35 protects the electrochemical cells 21 against downwardly directed projections, in particular from runoff water, and also protects the electrical conductors of the electrochemical battery from any unwanted contact. As can be seen in [Fig. 8], the upper plate 35 does not extend above the reservoir 3, 3'. The dimensions of the upper plate 35 can therefore be limited to the dimensions of the volume occupied by the electrochemical cells 21. The upper wall 9A of the reservoir 3, 3' can extend higher than the upper plate 35 so as to increase the capacity of the reservoir 3, 3'.

[0076] Advantageously, the frame 32 is formed by a series of profiled elements 36 fixed one after the other. Each profiled element 36 is rectilinear and extends horizontally. Each profiled element 36 has a constant section along the direction in which it extends. This section preferably has a rectangular shape with a small horizontal side and a large vertical side. The profiled elements are preferably made of aluminum, which offers a very good compromise between lightness and rigidity. The different profiled elements 36 are preferably welded one after the other. Thus the junction between the profiled elements 36 is watertight.

[0077] The frame 32 roughly comprises a rectangular shape. The frame 32 may nevertheless be narrower in the rear portion, at the height of the tank 3, 3'. The narrowness of the frame in the rear portion may be useful for arranging wheel arches of the vehicle.

[0078] The casing 30 also comprises a separator 37 (shown schematically in [Fig.l]) separating the electrochemical battery 4 from the reservoir 3, 3'. The separator 37 may advantageously be in the form of at least one profiled element similar to the profiled elements 36 described previously. The separator 37 may extend parallel to the transverse axis Y and connect two profiled elements 36 forming lateral sides of the frame 32. The separator 37 may also be welded at its two ends to the profiled elements 36 of the frame 32.

[0079] The lower plate 34 is fixed, for example screwed, against a lower face of the profiled elements 36 and against a lower face of the separator 37. Similarly, the upper plate 35 is fixed, for example screwed, against an upper face of the profiled elements 36 and against an upper face of the separator 37. The lower plate 34, the upper plate 35, the profiled elements 36 and the separator 37 thus form a sealed envelope around the electrochemical cells 21.

[0080] The casing 30 extends along the transverse axis Y over the width of the vehicle 1, and is therefore exposed to possible lateral impacts against the vehicle. Advantageously, the casing 30 further comprises shock absorbers 38 capable of absorbing the energy of an impact by case of collision of the vehicle against an obstacle. The shock absorbers 38 are in particular positioned along the left and right sides of the casing 30. The shock absorbers 38 extend parallel to the longitudinal axis X. The shock absorbers 38 are fixed, in particular screwed or welded, to lateral profiled elements 36.

[0081] According to another interesting aspect of the invention, the reservoir 3, 3' comprises a collar 41, or flange 41, at least partially surrounding the reservoir. The collar 41 is configured to fix the reservoir 3, 3' to the casing 30, and in particular to the frame 32. Preferably, the collar extends all around the reservoir 3, 3'. The collar comprises a portion extending horizontally by means of which the reservoir 3, 3' is fixed to the casing 30. This portion of the collar extends approximately halfway up the reservoir 3, 3' along the vertical axis Z. This portion of the collar comprises a plurality of fixing holes, these holes cooperating with fixing screws provided in the frame 32. Preferably, the collar 41 is made of metal, for example steel or aluminum.

[0082] According to one embodiment, the collar 41 is fixed against an upper face of the frame 32, in particular on an upper face of a portion of the profiled elements 36. The collar 41 can also be fixed against an upper face of the separator 37. According to this embodiment, the tank 3, 3' is therefore assembled to the frame 32 by bringing the tank from above and translating it downwards. Alternatively, the collar 41 could also be fixed against a lower face of the frame, in particular on a lower face of a portion of the profiled elements 36, and possibly a lower face of the separator 37. According to this embodiment, the tank 3, 3' is therefore assembled to the frame 32 by bringing the tank from below and translating it upwards.

[0083] According to a first embodiment, illustrated in [Fig.2], the collar 41 is attached to the structure of the tank 3. The collar is then advantageously fixed to the tank 3 using fixing interfaces 57 as described previously. According to this embodiment, the collar 41 therefore extends completely outside the structure of the tank 3.

[0084] According to a second embodiment, illustrated in [Fig.6], the collar 41 is anchored in the composite material forming the rigid structure of the tank 3'. The collar 41 therefore comprises a part embedded inside the structure of the tank. The collar 41 is thus integrated into the tank during the manufacture of the composite structure of the tank. As a note, the anchoring of the collar 41 in the rigid structure of the tank would also be possible with the tank 3 according to the first embodiment.

[0085] To design the energy storage device 2 previously described, the following design method can be adopted. First, an electro battery is identified existing electrochemical battery comprising a casing and a set of electrochemical cells supported by said casing. The existing electrochemical battery may, for example, be a mass-produced electrochemical battery or one intended to be mass-produced for a given vehicle model. The casing of the existing electrochemical battery comprises, in particular, a frame, a bottom plate and a top plate. Next, a portion of the electrochemical cells is removed from said set of electrochemical cells. Removing a portion of the electrochemical cells frees up space in said casing. Next, a reservoir is designed for storing an energy fluid whose geometric shape is adapted to occupy the space freed up by the removal of said portion of the electrochemical cells. Certain components of the existing energy storage device may possibly be modified to adapt to the shape of the reservoir.For example, the bottom plate and top plate of the existing energy storage device can be reduced to cover only the electrochemical cells, not the reservoir. The reservoir can potentially occupy a larger volume than the volume occupied by the removed electrochemical cells.

[0086] On the other hand, the frame of the tank advantageously remains unchanged. The interfaces for attaching the frame to the vehicle chassis can also remain unchanged. This design method can be implemented virtually on a computer, for example using computer-aided design (CAD) software.

[0087] The energy storage device 2 can therefore be designed and manufactured without modifying or by limiting the modifications made to an electrochemical battery casing initially intended to contain only electrochemical cells.

[0088] Finally, thanks to the invention, there is a vehicle equipped with an energy storage device comprising an electrochemical battery and a reservoir for an energy fluid. The energy storage device is particularly compact and thus allows a large volume to be retained for passengers and / or for transporting objects in the vehicle. The energy storage device is simple to install since it can be housed in place of a pre-existing electrochemical battery. The electrochemical battery and the reservoir can also be easily dismantled, for example for maintenance operations.

Claims

Claims

1. Energy storage device (2) for a motor vehicle (1), comprising: - a set of electrochemical cells (21), - a reservoir (3, 3') intended to store an energy fluid, and - a casing (30) intended to be fixed to a chassis (31) of the vehicle, the casing supporting the set of electrochemical cells and the reservoir.

2. Energy storage device (2) according to the preceding claim, characterized in that the casing (30) comprises a frame (32) extending laterally around the electrochemical cells and the reservoir.

3. Energy storage device (2) according to the preceding claim, characterized in that the frame (32) is formed by a series of profiled elements (36) fixed, in particular welded, one after the other.

4. Energy storage device (2) according to one of the preceding claims, characterized in that the casing (30) further comprises: - fixing lugs (33) adapted for fixing the energy storage device to the chassis (31) of the vehicle, and / or - shock absorbers (38) capable of absorbing the energy of an impact in the event of the vehicle colliding with an obstacle.

5. Energy storage device (2) according to one of the preceding claims, characterized in that the reservoir (3, 3') comprises a collar (41) at least partially surrounding the reservoir, and in that the reservoir is fixed to the casing (30) by means of its collar.

6. Energy storage device (2) according to the preceding claim, characterized in that the reservoir comprises a rigid structure made of a composite material, and in that the collar (41) is anchored in the composite material.

7. Energy storage device (2) according to claim 5, characterized in that the reservoir (3) comprises at least a first pair of opposite walls (7A, 7B) connected to each other by a first set of connecting elements (51), passing through the reservoir and extending parallel to a first axis (X), the reservoir comprising at least one fixing interface (57) arranged at one end of at least one connecting element (51, 52, 53), the collar (41) being fixed to the reservoir via the at least one fixing interface.

8. Energy storage device (2) according to one of claims 5 to 7 and according to one of claims 2 or 3, characterized in that the collar (41) is fixed against an upper face of the frame (32) or against a lower face of the frame.

9. Vehicle (1), in particular a motor vehicle, characterized in that it comprises a chassis (31) and an energy storage device (2) according to one of the preceding claims, the casing (30) of the energy storage device being fixed to the chassis.

10. A method of designing an energy storage device (2) according to one of claims 1 to 8, comprising: - identifying an existing energy storage device comprising a casing and a set of electrochemical cells supported by said casing, then - removing a portion of the electrochemical cells from said set of electrochemical cells, then - designing a reservoir intended to store an energy fluid, the reservoir comprising a geometric shape adapted so that the reservoir occupies the space freed by the removal of said portion of the electrochemical cells.

Images