Battery case equipped with a battery management system

Abstract

This battery enclosure for electrical energy storage comprises a tray (2) configured for mounting the battery's power elements (3), a bell (5) covering the tray (2), and mechanical means for attaching the bell (5) to the tray (2). The tray (2) includes means for electrically connecting the battery and means for thermally controlling the power elements (3). The tray and the bell form a containment structure to prevent thermal runaway of the power elements (3). The enclosure includes a battery management system (16), at least a portion (16a) of which is mounted outside the containment structure. [Fig. 2]

Description

Title of the invention: Battery housing equipped with a battery management system. Technical field

[0001] The present invention relates to the field of electrical energy storage, particularly in the field of aeronautics. More specifically, the invention relates to systems for monitoring operating conditions and managing batteries, for applications in which reducing mass and size is a significant issue, such as in aeronautical applications. Previous techniques

[0002] Classically, in the field of aeronautics, the storage of electrical energy is carried out by means of low voltage Lithium-Ion batteries, typically a voltage below 120V.

[0003] The term battery means a set of individual packs, each comprising modules made up of power elements and configured in combination in series and / or in parallel in order to achieve the desired electrical voltage and electrical capacity.

[0004] Modern aircraft have increasing electrical power requirements, which necessitates configuring batteries accordingly. Indeed, climate change is a major concern for many legislative and regulatory bodies worldwide. Various restrictions on carbon emissions have been, are being, or will be adopted by various states.

[0005] Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0006] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible, in order to reduce the environmental footprint of its activity.

[0007] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and finally aviation biofuels.

[0008] In order to provide the required electrical power while minimizing the weight of the electrical equipment, it is advantageous to increase the voltage of the batteries, for example to 800 V.

[0009] Conventionally, batteries are housed inside a casing consisting of a tray covered by a lid. The tray holds the installed batteries in place and also provides structural rigidity. Sufficient rigidity can be achieved by imposing a minimum wall thickness on the tray, but this results in a significant increase in the casing's mass. In an improved design, the minimum casing thickness can be reduced by means of localized reinforcements.

[0010] These solutions are accompanied by an increase in the mass of the casing, either by increasing the minimum thickness of the tray, or by providing reinforcements.

[0011] Furthermore, the cover allows the tank to be sealed airtight and integrates the electrical power and communication connections with electrical system management systems for diagnostic, control, and / or regulation purposes. The integration of the power and communication connections may increase the risk of gas leaks in the event of thermal runaway, as well as weaken the structural resistance.

[0012] Depending on the technologies, batteries may require a cooling system to ensure performance, lifespan and safety.

[0013] In particular, Lithium-Ion batteries with a high energy density relative to mass require significant monitoring of their operating conditions, such as voltage or temperature, and a cooling system to keep them within a reduced temperature range.

[0014] Beyond a temperature threshold known as "thermal runaway," internal exothermic chemical reactions can begin. When the battery is no longer able to dissipate sufficient heat, the cell temperature rises until it is destroyed. In other words, thermal runaway occurs in a battery when the energy released by the exothermic reactions occurring inside it exceeds the capacity to dissipate this energy outside the battery. This runaway can be followed by the generation of gas and an explosion and / or fire, which risks propagating the reaction to the other electrochemical cells of the battery.

[0015] To contain the phenomenon of thermal runaway, aircraft batteries are generally enclosed in a dedicated containment structure.

[0016] It is therefore necessary to cool the batteries through the containment structure put in place.

[0017] Classically, this cooling is achieved by a single-phase cooling fluid circuit installed near the cells and / or by one or more cold plates installed in the containment structure by means of sealed connectors.

[0018] However, establishing a cold zone within the battery containment structure presents several drawbacks. For example, the integration ratio, which is the ratio between the total mass of the equipment and the mass of the electrical power components of the equipment, is reduced. Furthermore, the risk of battery short-circuiting increases due to potential condensation.

[0019] Furthermore, in the event of thermal runaway, the proximity between the cooling circuit and the battery cells can increase the risk of damage to the cooling system, or even worsen the thermal runaway reaction by an explosive interaction of the cooling fluid (water) with the chemical components (such as lithium) of the electrical cells.

[0020] Document FR 3 131 454 - Al, filed on behalf of the Applicant, discloses an electrical battery enclosure in which the thermal control means for the power elements are located outside the containment structure. However, this document does not address battery management systems, also known by the acronym BMS (Battery Management System).

[0021] Classically, such a management system is placed either inside the containment structure or outside of it in a specific housing.

[0022] When the BMS is located inside the containment structure, it is not protected against thermal runaway. Furthermore, such a configuration does not improve the battery integration rate.

[0023] When the BMS is located outside the containment structure, it is housed in its own separate enclosure, which does not benefit from active cooling. Such a configuration is not optimal in terms of overall mass balance, given the additional weight of the BMS enclosure. Description of the invention

[0024] The invention aims to provide a battery housing integrating a battery management system (or BMS) which improves the overall mass balance and benefits from active cooling as well as protection against possible thermal runaway.

[0025] The invention relates to a housing for an electrical energy storage battery, comprising a tray configured to accommodate the battery's power elements, a bell covering the tray, and mechanical means for fixing the bell to the tray, the tray including means for electrical connection of the battery and means for thermal control of the power elements.

[0026] The platform and the bell form a containment structure to prevent thermal runaway of the power elements, the housing comprising a battery management system, at least part of which is mounted outside the containment structure. Such a housing ensures the protection of at least part of the battery management system against thermal runaway of the power elements. Furthermore, this configuration improves the battery integration rate and the overall mass balance.

[0027] Preferably, the part of the battery management system mounted outside the containment structure is in heat exchange contact with the thermal control means for the power elements. Such a housing allows for the sharing of thermal control means.

[0028] Advantageously, the heat exchange relationship between the part of the management system and the thermal control means is achieved through a layer of thermally conductive and electrically insulating material. The material layer optimizes the heat exchange relationship by ensuring a controlled contact surface and aims to reduce the risk of current leakage.

[0029] According to an optional feature, the part of the management system mounted in thermal exchange relationship with the thermal control means outside the containment structure is fixed to the tray by second chemical and / or mechanical fixing means.

[0030] According to another optional feature, the battery comprises a plurality of modules, the management system comprising for each module of the battery a master battery management unit, a plurality of battery sensor management units associated with the master management unit and battery sensors each associated with a power element of the module.

[0031] Preferably, the housing includes a high-level battery management unit configured to supervise a plurality of master battery management units.

[0032] Advantageously, the part of the management system mounted outside the containment structure includes the battery management units.

[0033] For example, the part of the management system mounted outside the containment structure includes the sensor management units.

[0034] For example, the means for thermal control of the power elements include a temperature regulation circuit for the power elements.

[0035] According to another aspect, the invention relates to an aircraft battery assembly, comprising a set of power elements and a housing as described above, in which the battery power elements are mounted.

[0036] According to another aspect, the invention relates to an aircraft comprising at least one battery assembly as described above. Brief description of the drawings

[0037] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0038] [Fig-1] is a perspective view of the main constituent elements of a housing conforming to an example of the invention;

[0039] [Fig.2] is a longitudinal cross-sectional view of a housing conforming to an example of the invention;

[0040] [Fig.3] illustrates an exploded view of a housing according to an example of the invention; and

[0041] [Fig.4] shows the housing of [Fig.3], in the closed position. Detailed description of at least one embodiment

[0042] Figures 1 to 4 show an example of an embodiment of a battery case according to an example of the invention, designated by the general numerical reference 1. The case 1 is intended to receive a battery.

[0043] In the described embodiment, the housing is intended to be carried on board an aircraft. It should be noted, however, that the invention also applies, in general, to other fields in which mass management and integration issues arise.

[0044] The housing is intended to provide mounting and connection for the battery's power elements and to protect the battery. It comprises a plate 2 onto which the battery's power elements 3 are mounted and a bell 5.

[0045] The platform 2 has the structural rigidity necessary to be able to accommodate by fixing the desired power elements 3.

[0046] The platform 2 is intended to provide temperature control functionality and, for this purpose, includes means for thermally controlling the power elements 3. For example, the thermal control means include a control circuit 6 for maintaining the temperature of the power elements 3 around an optimal operating temperature setpoint or within an optimal operating temperature range. For example, the control circuit may include pipes, such as 7, through which a heat transfer fluid circulates. The platform 2 is advantageously made of a thermally conductive material, in this case a metallic material.

[0047] The regulation circuit 6 is installed in thermal exchange relationship on the external face 8 of the platform 2, that is to say on the face opposite to the internal face 9 which accommodates the power elements 3. It can also be integrated into the platform 2.

[0048] The platform 2 is cooled or heated by the control circuit 6 and can consequently maintain the temperature of the power elements 3 within a range of optimal operating temperature. For example, an optimal operating temperature range is from 40°C to 60°C.

[0049] For example, the regulation circuit 6 includes metal tubes, such as 10, welded to the plate 2.

[0050] The platform 2 is equipped with several fastening elements 11 which allow its installation on board an aircraft. It should be noted, however, that the platform may alternatively consist of a structural aircraft support element designed for the integration of the battery.

[0051] As regards the bell 5, it covers all the elements located inside the housing 1 and represents a physical barrier which separates and protects the inside of the housing 1 and its external environment.

[0052] Bell 5 is specifically designed to reduce the risk of gas leaks.

[0053] In the event of a thermal runaway event, the bell 5 also provides protection for the external environment of the housing 1 by limiting the impact of this event on the external environment of the housing 1. It also provides a function for guiding the gases emitted by the battery during its operation. To this end, the bell 5 includes a profiled opening 12 for gas management, designed to guide the emitted gases in a desired direction. For example, the profiled opening 12 is held closed by a cover 13 that can rupture in the event of overpressure. In an embodiment not shown, the profiled opening 12 can advantageously be located on the base 2.

[0054] The bell 5 is made of a material that is both lightweight, resistant and suitable for ensuring the protective functionality in case of thermal runaway, for example in a ceramic matrix composite material or in a composite material comprising an internal thermal protection layer.

[0055] Thus, the plate 2 and the bell 5 constitute a containment structure for any thermal runaway of the power elements.

[0056] The housing includes a battery management system 16 (conventionally known as a "BMS" for Battery Management System), at least one part 16a of which is mounted outside the containment structure. Preferably, said part 16a of the battery management system 16 is in a heat exchange relationship with the thermal control means 6. In the case where a temperature control circuit 6 is integrated into the platform 2, the heat exchange relationship with part 16a is achieved through the platform 2.

[0057] Preferably, the heat exchange relationship between part 16a of the management system and the thermal control means 6 is achieved through a layer 17 of thermally conductive and electrically insulating material. Alternatively, the relationship heat exchange between part 16a and thermal control means 6 can be achieved without layer 17.

[0058] The battery management system 16 comprises, for each battery module, a master management unit, a plurality of battery sensor management units associated with the master management unit, and battery sensors 18, each associated with a power element of the module. The sensors 18 are temperature, voltage, and / or current sensors located near the power elements and within the containment structure. The battery management system 16 further comprises a high-level battery management unit configured to supervise a plurality of master battery management units.

[0059] Each sensor management unit includes a measurement module that receives temperature, voltage and / or current measurements from sensors 18 and a non-volatile memory module to store information such as module identification data, overvoltage data, undervoltage data, overheating data, or the number of charge / discharge cycles.

[0060] The measurements from the sensors 18 can be transmitted via a communication connector 15 ([Fig. 3]) linked to the sensor management units. Alternatively, the communication connector may include wall connectors capable of managing overpressure and temperature in the event of thermal runaway.

[0061] Each master battery management unit determines, for each power cell 3 of the module, a state of charge of the power cell based on data provided by the associated sensor management units. Each master battery management unit is capable of performing charge balancing operations on the power cells of the associated module.

[0062] Preferably, the master and high-level battery management units are integrated into part 16a of the battery management system 16 located outside the containment structure described above. The sensor management units can also be arranged in part 16a of the management system 16. Alternatively, the sensor management units may be placed as close as possible to the power elements 3, inside the containment structure.

[0063] The battery management units and sensor management units arranged in part 16a are integrated onto an electronic board, preferably fixed to the tray 2 by second chemical and / or mechanical fastening means 19. For example, the second means 19 include standoffs and screw or bolt-type fasteners.

[0064] With reference to [Fig. 3], the platform 2 includes means for electrically connecting the battery, comprising a power connector 14 necessary to supply electrical current to the aircraft systems, as well as means connection of means of communication, including a communication connector 15 with the battery management system for diagnostic, control and / or regulation purposes.

[0065] Finally, the housing is preferably equipped with first mechanical means of fixing the bell 5 to the plate 2, made for example in the form of screws, bolts or any other suitable means of fixing for the intended use.

Claims

Demands

1. Housing for an electrical energy storage battery, comprising a tray (2) configured for the attachment of power elements (3) of the battery, a bell (5) covering the tray (2), and mechanical attachment means for the bell (5) on the tray (2), the tray (2) comprising electrical connection means (14) for the battery and thermal control means (6) for the power elements (3), characterized in that the tray and the bell constitute a containment structure for any thermal runaway of the power elements, said housing comprising a battery management system (16) at least a part (16a) of which is mounted outside the containment structure and is in thermal exchange relationship with the thermal control means (6) for the power elements (3).

2. Housing according to claim 1, wherein the heat exchange relationship between said part (16a) of the management system and the thermal control means is achieved through a layer (17) of thermally conductive and electrically insulating material.

3. Housing according to claim 1 or 2, wherein the battery comprises a plurality of modules, the management system (16) comprising for each module of the battery a master battery management unit, a plurality of battery sensor management units associated with the master management unit and battery sensors (18) each associated with a power element (3) of the module.

4. Housing according to claim 3 comprising a high-level battery management unit configured to supervise a plurality of master battery management units.

5. Housing according to claim 3 or 4, wherein said part (16a) of the management system (16) mounted outside the containment structure comprises the battery management units.

6. Housing according to claim 5, wherein said part (16a) of the management system (16) mounted outside the containment structure comprises the sensor management units.

7. Housing according to any one of claims 1 to 6, wherein the thermal control means (6) of the power elements (3) 10 include a temperature regulation circuit for said power elements.

8. Aircraft battery assembly, comprising a set of power elements (3) and a housing (1) according to any one of claims 1 to 7, in which the power elements (3) of the battery are mounted.

9. Aircraft comprising at least one battery assembly according to claim 8.

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