POWER STORAGE SYSTEM FOR AN AIRCRAFT

Description

[0001] The invention relates to an electrical energy storage system for aircraft and an electrical energy distribution assembly comprising such a system.

[0002] An aircraft typically has an electrical system that includes a primary electrical power distribution circuit and a secondary electrical power distribution circuit. These primary and secondary distribution circuits, also known as primary or secondary distribution boxes, protect and distribute electrical power from internal sources, such as generators or batteries, or from external sources, such as power units, to payloads or to other distribution boxes within the aircraft.

[0003] Internal sources are thus known to include Li-Ion type batteries including electronic cards, cut-off elements, such as contactors, and fuses.

[0004] A cut-off element, such as a contactor, connected to the battery protects the battery by electrically insulating it.

[0005] However, such an architecture does not allow for optimizing the management of the battery and, in general, the electrical energy storage system.

[0006] There is therefore a need to provide an efficient electrical energy storage system for aircraft that does not have the aforementioned drawbacks. Examples of prior art are the following documents: FR2951320; US2014167655; and WO2014180662.

[0007] According to a first aspect, the invention relates to an electrical energy storage system for aircraft comprising at least one battery comprising a plurality of battery cell modules connected together by means of a secondary cut-off element specific to each module so as to form the at least one battery. In addition, at least one of the cut-off elements is a SSPC type contactor.

[0008] Thanks to the invention, the management of at least one battery is optimized.

[0009] Indeed, the battery is managed by managing all the modules forming the battery. Thus, the maintenance and repair steps are simplified thanks to the modular aspect of the invention, which results in cost savings. Safety is enhanced because the battery can continue to operate by isolating any module with a fault. The charging and pre-charging of each module is also optimized. It is even possible to eliminate the module pre-charging step.

[0010] Particular embodiments of the invention are defined in the dependent claims.

[0011] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which: there figure 1 is a diagram of an embodiment of a distribution assembly according to the invention; the figure 2 is a diagram of another embodiment of an assembly according to the invention.

[0012] As illustrated in the figures, the electrical energy distribution assembly of the invention 1 comprises at least one electrical energy storage system 3 and at least one main cut-off element 5 capable of electrically isolating said system 3.

[0013] The main cut-off element(s) 5 make it possible to manage the protections and electrical insulation of the storage system 3. In particular, the cut-off element(s) make it possible to protect the connecting elements, such as the cables, connecting the elements of the assembly of the invention 1 between them against a short circuit.

[0014] The main cut-off element(s) 5 can be sized to the nominal currents flowing through the storage system 3.

[0015] According to the invention, the cut-off element(s) are one or more Solid State Power Controller type contactors, known as “SSPC”. Said one or more SSPC contactors can be integrated and managed by a so-called “master” electronic card capable of managing other functions of the assembly of the invention 1.

[0016] One of the cut-off elements 5 can be associated with a fuse element 9. Said fuse element 9 can be calibrated to protect the storage system 3 of the invention from a short circuit.

[0017] The storage system of the invention 3 can be connected to a charger 7 or to several chargers intended to electrically charge said storage system 3.

[0018] The charger 7 can advantageously be connected in parallel with a main switching element 5.

[0019] The storage system 3 of the invention makes it possible to store electrical energy to power loads (not shown) in an aircraft (not shown) via the assembly of the invention.

[0020] The storage system 3 of the invention thus comprises at least one battery comprising a plurality of modules 11 comprising battery cells connected together by means of a secondary cut-off element 13 specific to each module 11 so as to form the at least one battery.

[0021] The modules 11 can be connected together in series and / or in parallel. Depending on the architecture chosen, it is advantageously possible to carry out a flight with a distribution assembly of the invention 1 having a different number of modules 11 if the energy required for said flight is less than the maximum capacity of the system of the invention 3. It is therefore possible to reduce the mass of the aircraft to have better performance. The invention therefore has the advantage of modularity that can be achieved in a simple and efficient manner.

[0022] Advantageously, the system of the invention 3 can limit the circulating current by disconnecting one or more modules 11.

[0023] To do this, the system of the invention 3 can comprise a switch to disconnect module by module or use the main disconnecting element 5 to disconnect all of the modules.

[0024] According to the invention, at least one of the cut-off elements 13 is a Solid State Power Controller type contactor, called “SSPC”. Said SSPC contactor does not allow the current entering the module to be cut off. It allows the unloaded modules 11 to be connected before the switching of the system of the invention 3 by the main cut-off element(s) 5. Thus, advantageously, the secondary cut-off elements 13 are sized to the nominal currents flowing through said modules 11.

[0025] Furthermore, in charging operation, an SSPC contactor, through its internal resistance, manages the current flowing through the module. This saves charging time for the system of the invention, slows down the aging of the module and reduces cell degradation. The performance, cost and safety of the system of the invention are improved.

[0026] Preferably, at least one of the cutting elements 13 is arranged in the module 11 specific to said cutting element 13. Such a configuration allows a maintenance step to be carried out more safely by the operator. Safety is thus improved.

[0027] Preferably, the system of the invention 3 comprises a means of communication or sending information (not shown) configured to send load shedding information out of the system of the invention 3 when at least one module 11 is loaded or overloaded. This makes it possible to reduce the consumption of said system of the invention 3.

[0028] As shown in the figure 2 , at least one module 11 is protected by a fuse element 19.

[0029] The fuse elements 19 can be arranged in series with all the modules 11 arranged in parallel in order to protect the entire storage system 3.

[0030] Said fuse element 19 may be, typically a cable, making it possible to connect said system of the invention 3 to the other elements of the assembly of the invention 1.

[0031] Said fuse element 19 can be calibrated to the power level of the module 11 and a chosen connecting element 21, typically a cable, making it possible to connect said system of the invention 3 to the other elements of the assembly of the invention 1. Said fuse element 19 thus provides protection for each module 11. The assembly formed by the fuse element 19, the modules 11 and the cut-off element 13 arranged in series is mounted in parallel in order to produce the storage system 3. The number of parallel connections can depend on the expected power.

[0032] Preferably, the system of the invention 3 comprises at least one connecting element 21 having a cross-section such that the ratio of the charging current as a function of the number of modules is optimized. In other words, the connecting element 19 of each module can be calibrated to the maximum of the current size of the load and the number of modules.

[0033] Thus, advantageously, the cross-section of the connecting elements of each module is reduced. This allows costs to be reduced by reducing the cross-section of the connecting element and the fuse rating, to facilitate the integration of the connecting elements and therefore of the aircraft and to limit the mass. In addition, in the event of load shedding, voltage outages are avoided.

[0034] In operation, during pre-charging, the system of the invention 3 can connect a single module 11. The capacities of the other modules are then charged at limited current via said single module.

[0035] The switching of the other charged modules is done at a substantially zero current. As a result, the pre-charging of all modules can be advantageously eliminated, allowing cost and mass savings.

[0036] Similarly, in charging operation, the system of the invention can optimize the charging of the modules by charging module by module. Thus, the system of the invention can choose to start charging with the most discharged module, the least discharged module or in parallel.

[0037] During maintenance of a module, the system of the invention can simply perform a charge on the loaded module(s).

[0038] Furthermore, said system of the invention makes it possible to unit test and isolate a defective module.

[0039] To do this, in the event of a fault being detected during operation, an interruption of a main cut-off element is necessary to disconnect said defective module. Such rapid switching makes it possible to carry out this action without impacting the operation of the aircraft since the system of the invention can continue to operate despite the disconnection of said module.

Claims

1. Electrical energy storage system (3) for an aircraft comprising at least one battery including a plurality of battery cell modules (11) connected to each other by means of a secondary disconnecting element (13) specific to each module (11) so as to form the at least one battery, at least one of the disconnecting elements (13) being an SSPC type contactor.

2. System (3) according to Claim 1, wherein at least one of the disconnecting elements (13) is arranged in the battery module (11) of said disconnecting element (13).

3. System (3) according to any one of the preceding claims, wherein at least one module (11) is protected by a fuse element (19).

4. System (3) according to any one of the preceding claims, comprising a communication means configured to send load-shedding information out of the storage system (3) when at least one module (11) is charged.

5. System (3) according to any one of the preceding claims, comprising at least one connecting element (21) having a cross-section such that the ratio of charging current to the number of modules is optimised.

6. Electrical energy distribution assembly (1) comprising at least one electrical energy storage system (3) according to any one of the preceding claims, and at least one main disconnecting element (5) capable of electrically isolating said system (3).

7. Assembly (1) according to the preceding claim, wherein the storage system (3) is connected to a charger (7).

8. Assembly according to the preceding claim, wherein the charger (7) is connected in parallel with the main disconnecting element (5).