Patent Publication Number: US-2023158979-A1

Title: Assembly for a vehicle comprising a plurality of batteries and an evacuation system

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of the French patent application No. 2112507 filed on Nov. 25, 2021, the entire disclosures of which are incorporated herein by way of reference. 
     FIELD OF THE INVENTION 
     The present invention relates to an assembly for a vehicle, in particular an aircraft, in which the assembly comprises a plurality of batteries and an evacuation system arranged to evacuate fluids away from the vehicle. The invention also relates to a vehicle fitted with such an assembly. 
     BACKGROUND OF THE INVENTION 
     An aircraft conventionally includes batteries, in particular lithium-ion batteries, to supply electricity to the apparatuses on the aircraft. 
       FIG.  7    shows an installation according to the prior art. The installation has two battery blocks  102   a - b , each of which comprises at least one battery, and each battery block  102   a - b  is contained in an enclosure  104   a - b  delimited by a wall that confines the battery block  102   a - b  in the event of failure of one of the batteries in the battery block  102   a - b.    
     If a battery is damaged, gases can propagate inside the enclosure  104   a - b . To evacuate these gases, the aircraft has an evacuation system  110  to evacuate the gases to outside the aircraft. 
     The evacuation system  110  is provided for two battery blocks  102   a - b  and includes an outlet orifice  106  that is arranged in the skin  108  of the aircraft, a T-fitting  114 , and, for each battery block  102   a - b , an evacuation duct  112   a - b  that is fluidly connected between the associated enclosure  104   a - b  and one of the inlets of the T-fitting  114 . 
     The evacuation system  110  also includes an output duct  118  fluidly connected between an outlet of the T-fitting  114  and the outlet orifice  106 . 
     The T-fitting  114  is fitted with a check valve  116 , in this case in the form of a ball that moves between the two inlets of the T-fitting  114  as a function of the pressure in each evacuation duct  112   a - b  to close the inlets alternately, thereby enabling gas to flow from one evacuation duct  112   a - b  to the outlet orifice  106 . 
     Consequently, in the event of a problem with the battery block  102   a , the pressurized gas flows through the evacuation duct  112   a  and pushes the ball against the other evacuation duct  112   b  to close the duct and to prevent the fluid from flowing towards the battery block  102   b . The gas then proceeds through the output duct  118  to the outlet orifice  106 . 
     If a battery is damaged, the battery can generate an overpressure that propagates through the ducts  112   a - b  and  118  and the T-fitting  114 . To withstand this overpressure, the ducts  112   a - b  and  118  have to be relatively strong. To ensure this strength, the ducts are made of metal, which makes the evacuation system  110  relatively heavy, and this has a negative effect on aircraft fuel consumption. 
     Furthermore, where a ball is used, means preventing the ball from being jammed by freezing are required, which makes the evacuation system  110  even heavier. 
     SUMMARY OF THE INVENTION 
     One objective of the present invention is to propose an assembly for a vehicle, in particular an aircraft, in which the assembly comprises a plurality of batteries and an evacuation system arranged to evacuate fluids away from the vehicle, and in which this evacuation system is lighter than in the prior art. 
     For this purpose, an assembly for a vehicle is proposed, the assembly comprising:
         at least two battery blocks, each of which comprises at least one battery,   for each battery block, a casing in which the battery block is enclosed and that has a connection face,   an outlet orifice arranged through an outer skin of the vehicle,   a main duct fluidly connected to the outlet orifice,   for each casing, an evacuation duct fluidly connected between the connection face of the casing and the main duct, and   a damping unit of a first type at the joint between each connection face and the associated evacuation duct and a damping unit of a second type at the joint between the main duct and the outlet orifice, in which each damping unit is designed to limit the amplitude of an overpressure propagating from the casing towards the outlet orifice,       

     wherein the assembly includes, associated with each casing, an enclosure delimited by a wall and in which the casing and the damping unit of the first type associated with the casing are seated, and wherein each evacuation duct is fluidly connected to the associated connection face through the wall of the corresponding enclosure, wherein each damping unit of the first type has a weakened zone made in the connection face of the casing, a chassis fastened sealingly between the evacuation duct and the connection face of the casing and including a window that passes through the chassis and faces the weakened zone, and a shutter mounted on the chassis that is moveable alternately between a closed position in which the shutter closes the window and an open position in which the shutter does not close the window, an actuator arranged to move the shutter from the open position to the closed position and vice versa, wherein each enclosure is fitted with a pressure sensor and a temperature sensor provided to measure the pressure and the temperature inside the enclosure, and the assembly has a control unit arranged to receive the measurements sent by the pressure sensors and the temperature sensors and to control each actuator. 
     Such an assembly enables an overpressure to be damped in the event of a battery being damaged, inter alia. 
     Advantageously, each enclosure has a temperature sensor provided to measure the temperature inside the enclosure, the assembly has a tank containing a pressurized inert gas, a network of overflow ducts with one end fluidly connected to the tank through an origin solenoid valve, for each enclosure, one end fluidly connected to the enclosure through a destination solenoid valve, and one end fluidly connected to the main duct through a destination solenoid valve, and a secondary control unit arranged to receive the measurements sent by the temperature sensors and to command each solenoid valve to close or to open. 
     The invention also proposes an aircraft including an outer skin and at least one assembly according to one of the preceding variants. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned and other features of the present invention are set out more clearly in the description given below of an example embodiment, the description being provided with reference to the attached drawings, in which: 
         FIG.  1    is a side view of an aircraft according to the invention, 
         FIG.  2    is a schematic view of an assembly according to a first embodiment of the invention, 
         FIG.  3    is a schematic view of an assembly according to a second embodiment of the invention, 
         FIG.  4    is a cross-section view of a damping unit according to a first embodiment of the invention, 
         FIG.  5    is a cross-section view of a damping unit according to a second embodiment of the invention, 
         FIG.  6    is a cross-section view of a damping unit according to a third embodiment of the invention, and 
         FIG.  7    is a schematic view of an assembly according to the prior art. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG.  1    shows an aircraft  100  that comprises a fuselage  102  with an outer skin  158 , inside which is fastened an assembly  150  according to the invention, as shown schematically in  FIG.  2    for a first embodiment of the invention and in  FIG.  3    for a second embodiment of the invention. Although the invention is described more specifically for an aircraft, it can be applied to any vehicle carrying battery blocks in operation. 
     In the first embodiment of the invention, the assembly  150  comprises a plurality of battery blocks  152   a - c  and each battery block  152   a - c  is enclosed in a casing  202  that confines the battery block  152   a - c  and has a connection face  203 . In the embodiment of the invention shown in  FIGS.  2  and  3   , there are three battery blocks  152   a - c , but the invention can be implemented using at least two battery blocks  152   a - c.    
     Each battery block  152   a - c  has at least one battery, in particular a lithium-ion battery. These batteries are intended to power the electrical apparatuses of the aircraft  100  via electrical conductors (not shown) running between the batteries and the electrical apparatuses. 
     The assembly  150  also has an evacuation system  160  that has an outlet orifice  156  that is arranged through the outer skin  158  of the aircraft  100 , a main duct  161  fluidly connected to the outlet orifice  156 , and, for each casing  202 , an evacuation duct  162   a - c  fluidly connected between the connection face  203  of the associated casing  202  and the main duct  161  and via this latter to the outlet orifice  156 . 
     Consequently, in the event of a problem with a battery block  152   a - c , the pressurized gas flows through the corresponding evacuation duct  162   a - c  to the main duct  161  and the outlet orifice  156 . 
     Depending on the problem with the battery block  152   a - c , an overpressure may be caused. This overpressure can then propagate through the evacuation ducts  162   a - c  and the main duct  161 . 
     To prevent such an overpressure from propagating, the evacuation system  160  includes a damping unit  170   a - c  of a first type at the joint between each connection face  203  and the associated evacuation duct  162   a - c  and a damping unit  170   d  of a second type at the joint between the main duct  161  and the outlet orifice  156 . 
     Each damping unit  170   a - d  is provided to limit the amplitude of the overpressure propagating from the casing  202  towards the outlet orifice  156  in the evacuation system  160 , and heavy rigid ducts are no longer required, allowing lighter ducts to be used. 
     The evacuation system  160  according to the invention no longer requires a T-fitting with a check valve system, enabling a simpler installation requiring less maintenance to be used. More than two battery blocks  152   a - c  can also be installed. 
     Each damping unit  170   a - c  of the first type associated with a casing  202  enables any overpressure coming out of the casing  202  through the connection face  203  towards the outlet orifice  156  to be attenuated, and performs the function of a check valve if an overpressure is generated from another casing  202 . 
     If a battery is damaged and generates an overpressure, the corresponding damping unit  170   a  of the first type dampens the overpressure propagating through the corresponding evacuation duct  162   a  and the main duct  161 , and if the overpressure reaching the main duct  161  is still relatively powerful, the damping unit  170   d  of the second type at the outlet orifice  156  dampens the overpressure before the overpressure is discharged to the outside. 
     In the second embodiment of the invention, each casing  202  is seated in an enclosure  154   a - c  delimited by a wall  205  that confines the battery block  152   a - c  enclosed in the casing  202  and the damping unit  170   a - c  of the first type associated with the casing  202 . 
     Each evacuation duct  162   a - c  is fluidly connected to the connection face  203  of the corresponding casing  202  through the wall  205  of the associated enclosure  154   a - c.    
       FIGS.  4  to  6    show different embodiments of a damping unit  370 ,  470 ,  570 . Each of  FIGS.  4  to  6    shows a damping unit  370 ,  470 ,  570  of the first type at the joint between a connection face  303 ,  403 ,  503  of the casing  302 ,  402 ,  502  and the associated evacuation duct  312 ,  412 ,  512 . Naturally, each damping unit  370 ,  470 ,  570  of the first type can adopt one or other of the different proposed forms. 
     In each of the embodiments, the casing  302 ,  402 ,  502  is fastened to the structure of the aircraft  100 . Where the casing  302 ,  402 ,  502  is in an enclosure  354 ,  454 ,  554 , the wall  372 ,  472 ,  572  of the enclosure  354 ,  454 ,  554  is also fastened to the structure of the aircraft  100  using first fastening means  103 . 
     The casing  302 ,  402 ,  502  can then be fastened to the wall  372 ,  472 ,  572  of the enclosure  354 ,  454 ,  554  or directly to the structure of the aircraft  100  using fastening means  101 , regardless of whether the casing  302 ,  402 ,  502  is seated in an enclosure  354 ,  454 ,  554  or otherwise. 
     In the embodiment shown in  FIG.  4   , the damping unit  370  of the first type includes a rupture disk  304  forming the connection face  303  of the casing  302  in which the battery block  352  is enclosed. The rupture disk  304  is a wall that is designed to break when the pressure exerted on the disk reached a predetermined threshold, and that has a mechanical strength value below the mechanical strength of the other faces of the casing  302  to ensure that the rupture disk  304  breaks before the other faces. 
     The damping unit  370  of the first type also has bellows  306  having a first end fastened sealingly to the casing  302  about the rupture disk  304  and a second end fastened sealingly to the inlet of the evacuation duct  312 . Consequently, if an overpressure is generated in the battery block  352 , the overpressure breaks the rupture disk  304 , which reduces the amplitude thereof and the bellows  306  are inflated under the effect of the overpressure, which also reduces the amplitude. 
     In the second embodiment, to confine the overpressure, for example in the event of the bellows  306  breaking, the wall  372  of the enclosure  354  encloses the battery block  352 , the casing  302  thereof, the inlet of the evacuation duct  312  and the bellows  306 . 
     In the embodiment of the invention shown in  FIG.  4   , the bellows  306  have a skirt  308  at each end to fasten the bellows, the skirt in this case being fastened using nuts  310  about the skirt  308  respectively to the casing  302  or to the evacuation duct  312 . To complete the seal, a ring gasket  313  is clamped between the skirt  308  and the casing  302  and a ring gasket  314  is clamped between the skirt  308  and the evacuation duct  312 . 
     In the embodiment shown in  FIG.  5   , the damping unit  470  of the first type includes a weakened zone  405  made in the connection face  403  of the casing  402  in which the battery block  452  is enclosed. The weakened zone  405  is, for example, an orifice or a pre-cut zone or a zone of lesser thickness than the other faces of the casing  402 . In general, the weakened zone  405  has a mechanical strength value below the mechanical strength of the other faces of the casing  402 . 
     The damping unit  470  of the first type also has a rupture disk  404  that is fastened between the connection face  403  of the casing  402  and the inlet of the evacuation duct  412 . To do so, the damping unit  470  has a chassis  413  against which the rupture disk  404  is held. The chassis  413  is fastened to the structure of the aircraft  100  or to the wall  472  of the enclosure  454  where present. 
     The damping unit  470  of the first type also has first bellows  406   a  with a first end fastened sealingly to the casing  402  about the weakened zone  405  and a second end fastened sealingly to a first face of the rupture disk  404 , and second bellows  406   b  with a first end fastened sealingly to a second face of the rupture disk  404  and a second end fastened sealingly to the inlet of the evacuation duct  412 . The two faces of the rupture disk  404  are opposite one another. 
     Consequently, if an overpressure is generated in the battery block  452 , the overpressure breaks the rupture disk  404 , which reduces the amplitude thereof and the bellows  406   a - b  are inflated under the effect of the overpressure, which also reduces the amplitude. 
     In the second embodiment, to confine the overpressure, for example in the event of the bellows  406   a - b  breaking, the wall  472  of the enclosure  454  encloses the battery block  452 , the casing  402  thereof, the inlet of the evacuation duct  412 , the rupture disk  404  and the bellows  406   a - b.    
     In the embodiment of the invention shown in  FIG.  5   , each of the bellows  406  has a skirt at each end to fasten the bellows, the skirt in this case being fastened using nuts about the skirt, to the rupture disk  404  and to the casing  402  or to the evacuation duct  412 . To complete the seal, a ring gasket is clamped between each skirt and the corresponding counterpart. 
     In the embodiment shown in  FIG.  6   , the damping unit  570  of the first type includes a weakened zone  505  made in the connection face  503  of the casing  502  in which the battery block  552  is enclosed. The weakened zone  505  is, for example, an orifice or a pre-cut zone or a zone of lesser thickness than the other faces of the casing  502 . In general, the weakened zone  505  has a mechanical strength value below the mechanical strength of the other faces of the casing  502 . 
     The damping unit  570  of the first type also has a chassis  514  that is fastened sealingly between the evacuation duct  512  and the connection face  503  of the casing  502 . In the embodiment of the invention shown in  FIG.  6   , the chassis  514  is fastened and fitted inside the inlet of the evacuation duct  512 . 
     In this case, the fastening is sealed by two ring gaskets  520  fastened between the chassis  514  and the casing  502 . 
     The chassis  514  has a window  516  traversing the chassis and a shutter  518  that is mounted on the chassis  514  and that is moveable alternately between a closed position in which the shutter  518  closes the window  516  and an open position in which the shutter  518  does not close the window  516 . The window  516  faces the weakened zone  505 . 
     To prevent the untimely opening of the shutter  518 , the damping unit  570  also has return means  507 , such as a spring, that constrain the shutter  518  in the closed position. The force exerted by the return means  507  should be enough to hold the shutter  518  in the closed position, but should not prevent the shutter  518  from opening when the pressure exerted on the shutter  518  exceeds a threshold. 
     In the embodiment of the invention shown in  FIG.  6   , the shutter  518  is mounted movably in rotation and opens towards the evacuation duct  512  and the return means  507  are for example a torsion spring. 
     Consequently, if an overpressure is generated in the battery block  552 , the overpressure pushes the shutter  518  towards the open position to open the window  516 , which reduces the amplitude of the overpressure. 
     In the second embodiment, to confine the overpressure in the event of a leak from the ring gaskets  520 , the wall  572  of the enclosure  554  encloses the battery block  552 , the casing  502  thereof, the inlet of the evacuation duct  512 , the chassis  514 , and the shutter  518 . 
     There is a hole  522 , for example with a diameter in the order of 1 mm to 2 mm, in the shutter  518  to balance the pressure on each side thereof. 
     The different embodiments described with reference to  FIGS.  4  to  6    are associated with a damping unit of the first type. For a damping unit of the second type, the outlet of the evacuation duct  312 ,  412 ,  512  is used in place of the casing  302 ,  402 ,  502  and the outlet orifice  156  is used in place of the evacuation duct  312 ,  412 ,  512 . The rupture disk or the shutter are then provided at the outlet of the evacuation duct  312 ,  412 ,  512  and the bellows, where present, are provided between the outlet of the evacuation duct  312 ,  412 ,  512  and the outlet orifice  156 . 
     The embodiments shown in  FIGS.  4  to  6    are passive damping units, but active damping units can also be used. 
     In the embodiment shown in  FIG.  6   , the return means  507  are replaced by an actuator  509 , for example a motor or a jack, that is arranged to move the shutter  518  from the open position to the closed position and vice versa. 
     The assembly  150  also includes a control unit  178  that, for example, includes the following, linked by a communication bus: a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), a storage unit such as a hard disk or a storage medium reader such as a secure digital (SD) card reader, and at least one communication interface enabling, for example, the control unit  178  to communicate with each actuator  509 , inter alia. 
     The processor is able to execute instructions loaded into the RAM from the ROM, an external memory (not shown), a storage medium (such as an SD card), or a communication network. When the equipment is powered up, the processor is able to read the instructions from the RAM and to execute the instructions. These instructions form a computer program causing the processor to implement some or all of the algorithms and steps described below. 
     Some or all of the algorithms and steps described below can be implemented in software form by executing a set of instructions using a programmable machine, such as a digital signal processor (DSP) or a microcontroller, or be implemented in hardware form using a dedicated component or machine, for example a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). 
     Each enclosure  154   a - c  is fitted with a sensor system  176  with a pressure sensor and a temperature sensor provided to measure the pressure and the temperature inside the enclosure  154   a - c , and the control unit  178  is arranged to receive the measurements sent by the pressure sensors and the temperature sensors. 
     The control unit  178  uses this information to determine whether or not there is a problem in one of the enclosures  154   a - c . Accordingly, there is a problem in an enclosure  154   a - c  if the temperature and/or the pressure in the enclosure  154   a - c  exceed predetermined thresholds, and there is no problem in the enclosure  154   a - c  if neither the temperature nor the pressure inside the enclosure  154   a - c  has exceeded the predetermined thresholds. 
     According to one specific embodiment, each enclosure  154   a - c  is fitted with such a damping unit of the first type. In normal operation, i.e., when no problem has been detected, the control unit  178  commands the actuator  509  associated with each enclosure  154   a - c  to position the associated shutter  518  in the open position, and when a problem is detected in an enclosure  154   a - c , the control unit  178  commands each actuator  509  corresponding to an enclosure  154   a - c  where no problem has been detected to position the corresponding shutter  518  in the closed position. Consequently, if a problem is detected in an enclosure  154   a - c , the shutters  518  corresponding to the other enclosures  154   a - c  are closed to prevent propagation to the healthy enclosures  154   a - c  and to reduce the amplitude of the overpressure. 
     According to another specific embodiment, each enclosure  154   a - c  is fitted with such a damping unit of the first type. In normal operation, the control unit  178  commands the actuator  509  of each enclosure  154   a - c  to position the associated shutter  518  in the closed position, and when a problem is detected in an enclosure  154   a - c , the control unit  178  commands the actuator  509  corresponding to the enclosure  154   a - c  to position the corresponding shutter  518  in the open position. Consequently, if a problem is detected in an enclosure  154   a - c , the shutter  518  corresponding to the enclosure  154   a - c  is opened to reduce the amplitude of the overpressure. 
     According to one specific embodiment, the assembly  150  has a tank  180  containing a pressurized inert gas, and a network of overflow ducts  182  with one end fluidly connected to the tank  180  through an origin solenoid valve  179 , for each enclosure  154   a - c , one end fluidly connected to the enclosure  154   a - c , and one end fluidly connected to the main duct  161 . 
     For each enclosure  154   a - c  and for the main duct  161 , the assembly  150  also has a destination solenoid valve  181  that is mounted at the end fluidly connected to the enclosure  154   a - c  or to the main duct  161  respectively. 
     Consequently, when the origin solenoid valve  179  is open, the inert gas spreads through the network of overflow ducts  182  and, depending on which destination solenoid valve  181  is open, the inert gas spreads into the enclosure  154   a - c  or the main duct  161  respectively and the evacuation duct  162   a - c  when the inert gas spreads through the main duct  161 . 
     This embodiment can be implemented with either of the active or passive embodiments described above. 
     The assembly  150  also has a secondary control unit that can be the same as described above or of another of the same type in communication therewith. In the embodiment of the invention shown in  FIG.  3   , the secondary control unit is considered to be the control unit  178 . 
     As in the active embodiments, each enclosure  154   a - c  includes a sensor system  176  with a temperature sensor provided to measure the temperature inside the enclosure  154   a - c , and the secondary control unit  178  is arranged to receive the measurements sent by each temperature sensor and to command the origin solenoid valve  179  to open or close alternately and to command each destination solenoid valve  181  to open or close. As before, the secondary control unit  178  determines whether or not there is a problem in one of the enclosures  154   a - c . Accordingly, there is a problem in an enclosure  154   a - c  if the temperature exceeds a predetermined threshold, and there is no problem if the temperature has not exceeded the predetermined threshold. 
     In normal operation, the secondary control unit  178  commands the origin solenoid valve  179  to close, thereby preventing the inert gas from flowing into the enclosures  154   a - c  and the main duct  161 . 
     If a problem is detected in an enclosure  154   a - c , the secondary control unit  178  commands the origin solenoid valve  179  to open, which enables the inert gas to flow through the network of overflow ducts  182 , and the secondary control unit  178  commands the destination solenoid valve  181  corresponding to each enclosure  154  with a problem to open, and the destination solenoid valves  181  of the other enclosures  154   a - c  and of the main duct  161  to close. 
     This injection of inert gas helps to reduce overheating and to prevent any flames from forming in the enclosure  154   a - c  where the problem has been detected. 
     Furthermore, each destination solenoid valve  181  is preferably a check valve to prevent the inert gas or overpressure gas from spreading from the enclosure  154   a - c  to the tank  180 . 
     While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.