High-voltage direct current battery system with low-voltage storage module

Abstract

The invention relates to a system comprising one of the battery modules (2) coupled to at least one control device and formed of battery cells arranged in parallel coherent chains of battery cells, the battery modules (2) being distributed in two independent networks including a high-voltage network (3) and a low-voltage network (4) coupled in series, the low-voltage network (4) including a battery module (2) including a first sub-network (4A) and a second sub-network (4B) electrically separated from the first sub-network (4A) by a physical separation element (8) arranged on the battery module (2) of the low-voltage network (4), characterised in that each battery module (2) of the high-voltage network (3) includes a number of parallel coherent chains of battery cells equal to the number of parallel coherent chains of battery cells of each battery module (2) of the first sub-network (4A).

Description

[0001] DESCRIPTION

[0002] TITLE: HIGH VOLTAGE DIRECT CURRENT BATTERY SYSTEM MODULED WITH LOW VOLTAGE STORAGE

[0003] Technical field

[0004] The present invention relates to electricity storage and restitution systems, in particular in vehicles using battery-type storage elements which constitute the only source of energy available for all on-board equipment.

[0005] The present invention aims in particular to constitute a hybrid storage system for electrically powered aircraft platforms making it possible to combine low-voltage and high-voltage returns.

[0006] Previous techniques

[0007] Electric propulsion for conventional aircraft (known as "CTOL" for "Conventional Take Off and Landing") or new mobility aircraft (known as "VTOL" for "Vertical Take Off and Landing") requires high electrical power which, for reasons of optimizing power density, engine efficiency and wiring masses, operates at high direct voltage (or "HVDC" for "High Voltage Direct Current") between six hundred Volts and eight hundred Volts.

[0008] This electrical power is provided by HVDC batteries sized to provide sufficient power to ensure an aircraft flight mission with the necessary safety margin.

[0009] These batteries are made up of battery cells coupled in series and in parallel coherent chains to obtain the expected characteristics.

[0010] To fit into the restricted volumes of an aircraft and be compatible with handling and personnel safety operations, the batteries include modular battery modules.

[0011] The modules comprise battery cells arranged on the one hand in series to provide the desired voltage as the sum of the elementary voltages of each battery cell in series, and arranged on the other hand in parallel coherent chains of cells in series to obtain the desired current or capacity in Ampere-hours as the sum of the currents or capacities of each parallel chain.

[0012] The management of the state of charge and the balancing of the cells is carried out by an electronic organ which manages the energy between the different cells so that they are electrically balanced between their state of charge, their voltage and their temperature.

[0013] These assemblies are commonly used as described in the following documents: EP2932574B 1 , EP3694015A1 ,

[0014] US20220140409A1 or EP2452391B 1.

[0015] However, with these known systems, the low voltage requirement for an aircraft's navigation equipment is either provided by dedicated low-voltage batteries which are of limited capacity, and therefore risk not providing the necessary energy over the entire duration of a flight, or by converters placed between the main high-voltage batteries for electric propulsion, which introduce the risk of propagating high-voltage currents to low-voltage equipment which could be destroyed by this voltage level in the event of a failure.

[0016] Furthermore, it is known to use a solution for drawing electrical power at an intermediate point of the assembly of high-voltage batteries in direct current at a low-voltage level, but this requires that there be an identical number of parallel paths in the cell assemblies or modules that are put in series for the correct management of the battery cells, which is not taught by the current state of the art.

[0017] Statement of the invention

[0018] The Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0019] This sustained research and development work focuses on new generations of aircraft engines, the lightening of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0020] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft.

[0021] The invention aims to overcome at least some of the aforementioned drawbacks and to propose a storage system capable of combining the advantages of speed, simplicity and reliability for its implementation, and this by delivering low-voltage and high-voltage direct current.

[0022] In view of the above, the subject of the invention is a high-voltage and low-voltage direct current hybrid battery system, comprising battery modules coupled to at least one control device and formed of battery cells arranged in parallel coherent strings of battery cells, the battery modules being distributed into two independent networks including a high-voltage network and a low-voltage network coupled in series, the low-voltage network comprising a battery module comprising a first sub-network and a second sub-network electrically separated from the first sub-network by a physical separation element arranged on the battery module of said low-voltage network, each battery module of the high-voltage network comprising a number of parallel coherent strings of battery cells equal to the number of parallel coherent strings of battery cells of each battery module of the first sub-network.

[0023] Preferably, the high-voltage network and the low-voltage network are each coupled to and controlled by a separate dedicated control device.

[0024] For example, battery cells are adapted to be able to deliver a capacity of between five and twenty Ampere-hours.

[0025] Advantageously, each battery module fits in a parallelepiped having a height of between one hundred and eight and one hundred and twenty-eight millimeters, a width of between three hundred and twenty-one and three hundred and thirty-one millimeters, and a length of between three hundred and eighty-three and four hundred and three millimeters.

[0026] According to one embodiment, the battery modules of the high-voltage network and the first sub-network are formed from the same number of battery cells, this number being an integer multiple of the number of parallel coherent strings of battery cells of the first sub-network.

[0027] In one embodiment, the battery modules each comprise ninety-six battery cells, the high-voltage network comprises seven battery modules coupled in series and the low-voltage network comprises a battery module which includes the first and second electrically separated sub-networks, the physical separation element being configured so that the first sub-network comprises four parallel coherent strings of twelve battery cells such that on the one hand the second sub-network comprises eight parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network comprise four parallel coherent strings of twenty-four battery cells.

[0028] Advantageously, the battery modules each comprise ninety-six battery cells, the high-voltage network comprises seven battery modules coupled in series and the low-voltage network comprises a battery module which includes the first and second electrically separated sub-networks, the physical separation element being configured so that the first sub-network comprises four parallel coherent strings of eight battery cells so that on the one hand the second sub-network comprises eight parallel coherent strings of eight battery cells and on the other hand the modules of the high-voltage network comprise four parallel coherent strings of twenty-four battery cells.

[0029] The system may further provide that the battery modules each comprise ninety-six battery cells, the high-voltage network comprising five battery modules coupled in series and the low-voltage network comprising a battery module which includes the first and second electrically separated sub-networks, the physical separation element being configured so that the first sub-network comprises three parallel coherent strings of twelve battery cells such that on the one hand the second sub-network comprises five parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network comprise three parallel coherent strings of thirty-two battery cells.

[0030] Preferably, the system is adapted to fit into a parallelepiped having a height and length of between four hundred and fifty and five hundred millimeters, and a width of between six hundred and fifty and six hundred and ninety millimeters.

[0031] The invention also relates to an aircraft comprising a system as described above.

[0032] Brief description of the drawings

[0033] The invention will be better understood from a detailed study of some embodiments taken as non-limiting examples and illustrated by the appended drawings, in which:

[0034] [Fig 1] represents a battery system according to a first particular embodiment.

[0035] [Fig 2] shows a second embodiment of the battery system.

[0036] [Fig 3] shows a housing for the battery module.

[0037] [Fig 4] shows the battery modules coupled to an aircraft engine.

[0038] [Fig 5] represents a first view of the installation of the system in an aircraft.

[0039] [Fig 6] represents a second view of the system's installation in an aircraft.

[0040] Detailed description

[0041] In the first embodiment illustrated in Figure 1, the high-voltage and low-voltage direct current hybrid battery system 1 comprises battery modules 2 coupled to at least one control device and formed of battery cells arranged in parallel coherent chains of battery cells. The battery modules 2 are divided into two independent networks, including a high-voltage network 3 and a low-voltage network 4 coupled in series.

[0042] The low-voltage network 4 comprises a battery module 2 comprising a first sub-network 4A and a second sub-network 4B electrically separated from the first sub-network 4A by a physical separation element 8 arranged on the battery module 2 of said low-voltage network 4.

[0043] Each battery module 2 of the high-voltage network 3 comprises a number of parallel coherent strings of battery cells equal to the number of parallel coherent strings of battery cells of each battery module 2 of the first sub-network 4A.

[0044] Thus, the system benefits from the structuring of the battery modules 2 to constitute on the one hand the assembly of the high-voltage battery network 4A, used in particular for propulsion in an aircraft, and on the other hand a dedicated and segregated assembly constituted by the low-voltage network 4B to supply the low-voltage equipment of this aircraft.

[0045] Thus, from battery modules 2 consisting of a defined number of battery cells arranged in series in parallel chains of each module 2 to have the desired voltage level V3 and the expected capacity in Ampere-hours between the input of the high-voltage network 6 and the outputs 5,7 of the low-voltage network 4, it is possible to easily define the chains in each module 2.

[0046] The physical separation element arranged between the first and second sub-networks 4A, 4B of cells of the battery module 2 forming the low-voltage network 4 is provided to prevent any propagation of faults from one sub-network 4A, 4B to the other, as well as to form an electrical interface to both be able to output sufficient propulsion power from the first sub-network 4A and independently connect the non-propulsion power to the various consumers thanks to the second sub-network 4B. In addition, the high-voltage network 3 and the low-voltage network 4 can each be coupled to a separate dedicated control device and controlled by it.

[0047] In particular, a control device dedicated solely to the first sub-network 4A can be provided.

[0048] This allows monitoring of the V2 voltages and currents of the first 4A sub-network, to manage the correct balancing of its battery cells.

[0049] For example, the battery cells are adapted to deliver a capacity of between five and twenty ampere-hours.

[0050] The voltage, capacity and current performance of cells are characteristic of their chemistry.

[0051] Thus, considering a cell voltage of four point two Volts, the capacity is of the order of five Ampere-hours to twenty Ampere-hours, typically ten Ampere-hours.

[0052] Considering a structure of the battery module 2 with ninety-six cells, an assembly of twenty-four cells in series and four coherent chains in parallel for the high-voltage network 3, a battery module 2 of the high-voltage network 3 is produced delivering a voltage V3 of one hundred Volts and having a capacity of forty Ampere-hours.

[0053] In the first embodiment, the high-voltage network 3 further comprises seven battery modules 2 coupled in series and the low-voltage network 4 comprises a battery module 2 which includes the first and second electrically separated sub-networks 4A, 4B, the physical separation element 8 being configured so that the first sub-network 4A comprises four parallel coherent strings of twelve battery cells so that on the one hand the second sub-network 4B comprises eight parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network 4A comprise four parallel coherent strings of twenty-four battery cells.

[0054] Thus, the low-voltage network 4 comprises twelve cells in series of eight coherent chains in parallel, which allows its module 2 to deliver a voltage V2 of fifty Volts and a capacity of eighty Ampere-hours.

[0055] Considering a division of said module 2 of the low-voltage network 4 into two sub-networks of battery cells 4A, 4B using the physical separation element 8, the first and second electrically separated sub-networks 4A, 4B are produced, each of fifty Volts and forty Ampere-hours.

[0056] The advantage of this structuring of the battery modules 2 is to have a high-voltage network 3 configured to have a voltage V3 of seven hundred and fifty Volts with a capacity of forty Ampere-hours for electric propulsion, with a coherent chain of four chains of battery cells in parallel whose balancing is ensured by the control device dedicated solely to the first sub-network 4A, and a battery pack configured to have a voltage V2 of fifty Volts and forty Ampere-hours which can be managed by a second control device and dedicated to powering the low-voltage equipment.

[0057] For example, the battery modules 2 of the high-voltage network 3 and the first sub-network 4A are formed from the same number of battery cells, this number being an integer multiple of the number of parallel coherent strings of battery cells of the first sub-network 4A.

[0058] In a second embodiment illustrated by Figure 2, the battery modules 2 each comprise ninety-six battery cells, the high-voltage network 3 comprises seven battery modules 2 coupled in series and the low-voltage network 4 comprises a battery module 2 which includes the first and second electrically separated sub-networks 4A, 4B, the physical separation element 8 being configured so that the first sub-network 4A comprises four parallel coherent strings of eight battery cells so that on the one hand the second sub-network 4B comprises eight parallel coherent strings of eight battery cells and on the other hand the modules of the high-voltage network 4A comprise four parallel coherent strings of twenty-four battery cells.

[0059] Thus, the second embodiment of the system 1 is slightly different from the first embodiment in that the low-voltage network 4 comprises a module 2 of the low-voltage network 4 having eight battery cells in series and twelve coherent chains in parallel delivering a voltage V2 of thirty-three Volts per one hundred and twenty Ampere-hours.

[0060] In the second embodiment, the first and second sub-networks 4A, 4B are configured to be able to deliver a voltage V2 of thirty-three Volts and respectively forty Ampere-hours, to be consistent with the high-voltage chain, and eighty Ampere-hours, for the low-voltage loads.

[0061] The advantage of this structuring of the battery modules 2 of the second embodiment makes it possible to have a high-voltage battery pack configured to have a voltage V3 of seven hundred and forty Volts having a capacity of forty Ampere-hours for electric propulsion, with a coherent chain of four chains of cells in parallel that can be managed by the first control device to ensure balancing and monitoring, and a battery pack configured to have a voltage V2 of thirty-three Volts having a capacity of eighty Ampere-hours, coherent that can be managed by a second control device to power the low-voltage equipment.

[0062] This V2 voltage of thirty-three Volts for low-voltage equipment is consistent with the regulatory voltage envelope of the aeronautical standard “DO 160” for which they are designed and qualified.

[0063] Figures 3 and 4 illustrate that each battery module 2 can, for example, fit into a parallelepiped having a height DI of between one hundred and eight and one hundred and twenty-eight millimeters, a width D2 of between three hundred and twenty-one and three hundred and thirty-one millimeters, and a length D3 of between three hundred and eighty-three and four hundred and three millimeters, which allows these modules 2 to be very compact, and to be able to install them homogeneously in the aircraft insofar as they are of the same dimensions and therefore can be integrated into identical housings 9.

[0064] In a third embodiment, the battery modules 2 each comprise ninety-six battery cells, the high-voltage network 3 comprises five battery modules 2 coupled in series and the low-voltage network 4 comprises a battery module 2 which includes the first and second electrically separated sub-networks 4A, 4B, the physical separation element 8 being configured so that the first sub-network 4A comprises three parallel coherent strings of twelve battery cells so that on the one hand the second sub-network 4B comprises five parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network 4A comprise three parallel coherent strings of thirty-two battery cells.

[0065] For an electric propulsion chain with battery cells of four point two Volts and a capacity of five Ampere-hours per cell, the third embodiment comprises six battery modules 2 in series consisting of five modules 2 which deliver a voltage V3 of one hundred and thirty-four Volts each and sixty Ampere-hours, as well as a battery module 2 which delivers a voltage V2 of fifty Volts of which the first sub-network 4A has a capacity of sixty Ampere-hours for the propulsion chain and the second sub-network 4B has one hundred Ampere-hours for the avionics.

[0066] The assembly thus constituted of six geometrically identical battery modules 2 produces a high-voltage battery for the aircraft propulsion chain delivering a voltage V3 of seven hundred and twenty-two Volts and sixty Ampere-hours and a low-voltage battery for the avionics delivering a voltage V2 of fifty Volts and one hundred Ampere-hours.

[0067] As illustrated by Figures 5 and 6, the system can be adapted to fit into a parallelepiped having a height D5 and a length D4 of between four hundred and fifty and five hundred millimeters, and a width of between six hundred and fifty and six hundred and ninety millimeters.

[0068] Thanks to the identical dimensions of the six battery modules 2 described above, installation on an aircraft is facilitated by the homogeneity of the housings 9 in the areas dedicated to the electrical energy storage elements of the aircraft, in particular electrically powered aircraft which only have this type of energy on board to ensure both the power supply of the propulsion members 10 and the power supply of the navigation equipment (avionics, radio, lighting, etc.). The invention therefore also relates to an aircraft comprising a system 1 as described above.

[0069] A high-voltage battery system 1 for electric propulsion is thus produced, making it possible to supply low-voltage energy to power low-voltage navigation equipment, and in which the battery cells assembled in each battery module 2 are managed by the corresponding dedicated control devices as if they were independent batteries but integrated into identical mechanical structures, thanks to chains of parallel coherent cells originating from the assemblies of battery modules 2.

[0070] These chains allow for physically and functionally independent paths managed independently between high-voltage and low-voltage equipment, ensuring that there can be no high-voltage propagation on low-voltage circuits and equipment.

Claims

CLAIMS 1. High-voltage and low-voltage direct current hybrid battery system (1), comprising battery modules (2) coupled to at least one control device and formed of battery cells arranged in parallel coherent chains of battery cells, the battery modules (2) being distributed into two independent networks including a high-voltage network (3) and a low-voltage network (4) coupled in series, the low-voltage network (4) comprising a battery module (2) comprising a first sub-network (4A) and a second sub-network (4B) electrically separated from the first sub-network (4A) by a physical separation element (8) arranged on the battery module (2) of said low-voltage network (4),characterized in that each battery module (2) of the high-voltage network (3) comprises a number of parallel coherent strings of battery cells equal to the number of parallel coherent strings of battery cells of each battery module (2) of the first sub-network (4A)., 2. System (1) according to claim 1, wherein the high-voltage network (3) and the low-voltage network (4) are each coupled to and controlled by a separate dedicated control device.

3. System (1) according to any one of claims 1 and 2, in which the battery cells are adapted to be able to deliver a capacity of between five and twenty Ampere-hours.

4. System (1) according to any one of the preceding claims, wherein each battery module (2) fits in a parallelepiped having a height (D1) of between one hundred and eight and one hundred and twenty-eight millimeters, a width (D2) of between three hundred and twenty-one and three hundred and thirty-one millimeters, and a length (D3) of between three hundred and eighty-three and four hundred and three millimeters.

5. System (1) according to any one of the preceding claims, in which the battery modules (2) of the high-voltage network (3) and the first sub-network (4A) are formed from the same number of battery cells, this number being an integer multiple of the number of parallel coherent strings of battery cells of the first sub-array (4A).

6. System (1) according to any one of the preceding claims, wherein the battery modules (2) each comprise ninety-six battery cells, the high-voltage network (3) comprises seven battery modules (2) coupled in series and the low-voltage network (4) comprises a battery module (2) which includes the first and second electrically separated sub-networks (4A, 4B), the physical separation element (8) being configured so that the first sub-network (4A) comprises four parallel coherent strings of twelve battery cells so that on the one hand the second sub-network (4B) comprises eight parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network (4A) comprise four parallel coherent strings of twenty-four battery cells.

7. System (1) according to any one of claims 1 to 6, wherein the battery modules (2) each comprise ninety-six battery cells, the high-voltage network (3) comprises seven battery modules (2) coupled in series and the low-voltage network (4) comprises a battery module (2) which includes the first and second electrically separated sub-networks (4A, 4B), the physical separation element (8) being configured so that the first sub-network (4A) comprises four parallel coherent strings of eight battery cells so that on the one hand the second sub-network (4B) comprises eight parallel coherent strings of eight battery cells and on the other hand the modules of the high-voltage network (4A) comprise four parallel coherent strings of twenty-four battery cells.

8. System (1) according to any one of claims 1 to 6, wherein the battery modules (2) each comprise ninety-six battery cells, the high-voltage network (3) comprises five battery modules (2) coupled in series and the low-voltage network (4) comprises a battery module (2) which includes the first and second electrically separated sub-networks (4A, 4B), the physical separation element (8) being configured so that the first sub-network (4A) comprises three parallel coherent strings of twelve cells of battery so that on the one hand the second sub-network (4B) comprises five parallel coherent strings of twelve battery cells and on the other hand the modules of the high-voltage network (4A) comprise three parallel coherent strings of thirty-two battery cells.

9. System (1) according to any one of the preceding claims, adapted to fit in a parallelepiped having a height (D5) and a length (D4) of between four hundred and fifty and five hundred millimeters, and a width of between six hundred and fifty and six hundred and ninety millimeters.

10. Aircraft comprising a system (1) according to any one of the preceding claims.

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