Battery housing provided with a battery management system

Abstract

The invention relates to a housing (1) for an electric energy storage battery, which includes a platform (2) configured so that power elements (3) of the battery attach thereto, a protective cover (5) covering the platform (2), and means for mechanically attaching the protective cover (5) to the platform, the platform (2) comprising means for electrical connection of the battery and means (6) for thermal management of the power elements (3). The platform and the protective cover form a structure for containing any thermal runaway of the power elements (3), the housing comprising a battery management system (16) of which at least one portion (16a) is mounted outside the containment structure and is in a heat-exchange relationship with the thermal control means (6) of the power elements (3).

Description

[0001] DESCRIPTION

[0002] TITLE: Battery case with battery management system

[0003] Technical field

[0004] The present invention relates to the field of electrical energy storage, in particular in the field of aeronautics. More specifically, the invention relates to systems for monitoring operating conditions and battery management, for applications in which reducing mass and size are an important issue, such as an aeronautical application.

[0005] Previous techniques

[0006] Traditionally, in the aeronautics field, the storage of electrical energy is carried out using low-voltage Lithium-Ion batteries, typically a voltage lower than 120V.

[0007] 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.

[0008] Modern aircraft have increasing electrical power requirements, requiring battery configurations accordingly. Indeed, climate change is a major concern for many legislative and regulatory bodies around the world. Various carbon emission restrictions have been, are being, or will be adopted by various states.

[0009] For several years now, civil aviation has been mobilizing to contribute to the fight against climate change.

[0010] Technological research efforts have already made it possible to significantly improve 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.

[0011] This ongoing 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 aeronautical biofuels.

[0012] In order to provide the required electrical power while minimizing the weight of the electrical equipment, it is interesting to increase the battery voltage, for example to 800 V.

[0013] Conventionally, batteries are arranged inside a housing consisting of a tray covered by a hood. The tray holds the installed batteries in position and also ensures the structural rigidity of the tray. Sufficient rigidity can be achieved by imposing a minimum thickness on the tray wall, but this is accompanied by a significant increase in the mass of the housing. In an improved design, the minimum thickness of the housing can be reduced using localized reinforcements.

[0014] These solutions are accompanied by an increase in the mass of the housing, whether by increasing the minimum thickness of the tank, or by providing reinforcements.

[0015] Furthermore, the cover allows the container to be sealed and integrates the electrical power and communication connectors with electrical system management systems for diagnostic, control and / or regulation purposes. The integration of power and communication connectors may be accompanied by an increased risk of gas leaks in the event of thermal runaway, as well as a weakening of the structural strength. Depending on the technology, batteries may require a cooling system to ensure performance, lifespan and safety.

[0016] 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.

[0017] Beyond a temperature threshold known as "thermal runaway", exothermic internal chemical reactions may begin. When the battery is no longer able to dissipate enough heat, the cell temperature increases 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 may be followed by the generation of gas and an explosion and / or fire, which risks spreading the reaction to the other electrochemical cells in the battery.

[0018] To contain the thermal runaway phenomenon, aircraft batteries are generally enclosed in a dedicated containment structure.

[0019] It is therefore necessary to cool the batteries through the containment structure put in place.

[0020] Conventionally, 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.

[0021] However, the implementation of a cold zone inside the battery containment structure has several disadvantages. Thus, the integration rate constituted by the ratio between the total mass of the equipment and the mass of the electrical power elements of the equipment is reduced. The risk of short circuiting of the battery increases because of the condensation that can occur. 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 aggravate the thermal runaway reaction by an explosive interaction of the cooling fluid (water) with the chemical components (such as lithium) of the electric cells.

[0022] Document FR 3 131 454 - A1 in the name of the Applicant discloses an electrical box for a battery, in which the thermal control means of the power elements are located outside the containment structure. However, this document does not deal with battery management systems, also known by the acronym BMS for "Battery Management System" in English.

[0023] Typically, such a management system is placed either inside the containment structure or outside it in a specific housing.

[0024] When the BMS is inside the containment structure, it is not protected against thermal runaway. Moreover, such a configuration does not improve the battery integration rate.

[0025] When the BMS is located outside the containment structure, it is placed in an additional housing of its own, which does not benefit from active cooling. Such a configuration is not optimal in the overall mass balance, given the additional weight brought by the BMS housing.

[0026] Statement of the invention

[0027] The aim of the invention is to propose a battery case integrating a battery management system (or BMS) which improves the overall mass balance and which benefits from active cooling as well as protection against possible thermal runaway.

[0028] The invention relates to a housing for an electrical energy storage battery, comprising a tray configured so that power elements of the battery can be fixed thereto, a bell covering the tray, and means for mechanically fixing the bell to the tray, the tray comprising means for electrically connecting the battery and means for thermally controlling the power elements.

[0029] The tray and the bell constitute a containment structure for any thermal runaway of the power elements, the housing comprising a battery management system of which at least a part is mounted outside the containment structure. Such a housing makes it possible to guarantee the protection of at least a part of the battery management system against thermal runaway of the power elements. In addition, such a configuration improves the integration rate of the batteries and the overall mass balance.

[0030] According to one feature, the part of the battery management system mounted outside the containment structure is in heat exchange relationship with the thermal control means of the power elements. Such a housing makes it possible to share the thermal control means.

[0031] 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 layer of material makes it possible to optimize the heat exchange relationship by guaranteeing a controlled contact surface and aims to reduce the risks of current leaks.

[0032] 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.

[0033] 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. Preferably, the housing comprises a high-level battery management unit configured to supervise a plurality of master battery management units.

[0034] Advantageously, the portion of the management system mounted externally to the containment structure comprises the battery management units.

[0035] For example, the part of the management system mounted outside the containment structure includes the sensor management units.

[0036] For example, the thermal control means of the power elements comprise a temperature regulation circuit of the power elements.

[0037] According to another aspect, the invention relates to a battery assembly for an aircraft, comprising a set of power elements and a housing as described above, in which the power elements of the battery are mounted.

[0038] According to another aspect, the invention relates to an aircraft comprising at least one battery assembly as described above.

[0039] Brief description of the drawings

[0040] 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:

[0041] [Fig 1] is a perspective view of the main constituent elements of a housing according to an example of the invention;

[0042] [Fig 2] is a longitudinal sectional view of a housing according to an example of the invention;

[0043] [Fig 3] illustrates an exploded view of a housing according to an example of the invention; and

[0044] [Fig 4] shows the case of Figure 3, in the closed position.

[0045] Detailed description of at least one embodiment Figures 1 to 4 show an exemplary embodiment of a battery case according to an example of the invention, designated by the general reference numeral 1. The case 1 is intended to receive a battery.

[0046] In the embodiment described, the housing is intended to be mounted on board an aircraft. It will be noted, however, that the invention also applies, in general, to other fields in which problems of mass management and integration arise.

[0047] The housing is intended to ensure the mounting and connection of the battery power elements and to ensure the protection of the battery. It comprises a plate 2 on which the battery power elements 3 are fixed and a bell 5.

[0048] Tray 2 has the necessary structural rigidity to accommodate the desired power elements 3 by fixing.

[0049] The plate 2 is intended to provide a temperature management functionality, and for this purpose comprises means for thermally controlling the power elements 3. For example, the thermal control means comprise a regulation circuit 6 intended to maintain the temperature of the power elements 3 around an optimal operating temperature setpoint or within an optimal operating temperature range. For example, the regulation circuit may comprise pipes, such as 7, inside which a heat transfer fluid circulates. The plate 2 is advantageously made of a thermally conductive material, in this case a metallic material.

[0050] The regulation circuit 6 is installed in a heat exchange relationship on the external face 8 of the plate 2, that is to say on the face opposite the internal face 9 which accommodates the power elements 3. It can also be integrated into the plate 2.

[0051] The plate 2 is cooled or heated by the control circuit 6 and can therefore maintain the temperature of the power elements 3 within an optimal operating temperature range. For example, an optimal operating temperature range is from 40°C to 60°C.

[0052] For example, the control circuit 6 comprises metal tubes, such as 10, welded to the plate 2.

[0053] The tray 2 is equipped with several fixing elements 1 1 which allow its installation on board an aircraft. It will be noted, however, that the tray may be constituted, as a variant, by a structural element supporting the aircraft provided for the integration of the battery.

[0054] With regard to the bell 5, this covers all the elements located inside the housing 1 and represents a physical barrier which separates and protects the interior of the housing 1 and its external environment.

[0055] Bell 5 is intended in particular to reduce the risk of gas leaks.

[0056] In the event of a thermal runaway type event, the bell 5 also provides a function of protecting 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 of guiding the gases emitted by the battery during its operation. The bell 5 comprises for this purpose a profiled opening 12 intended for gas management and provided so that the emitted gases are guided in a desired direction. For example, the profiled opening 12 is kept closed by a cover 13 capable of breaking in the event of overpressure. In an embodiment not shown, the profiled opening 12 can advantageously be placed on the base 2.

[0057] The bell 5 is made of a material that is both light and strong and capable of providing the protective functionality in the event of thermal runaway, for example in a ceramic matrix composite material or in a composite material comprising an internal thermal protection layer.

[0058] Thus, plate 2 and bell 5 constitute a containment structure for any thermal runaway of the power elements.

[0059] The housing comprises a battery management system 16 (conventionally known as “BMS”), at least a portion 16a of which is mounted outside the containment structure. Advantageously, the portion 16a of the battery management system 16 is in heat exchange relationship with the thermal control means 6. In the case where a temperature regulation circuit 6 is integrated into the tray 2, the heat exchange relationship with the portion 16a is achieved through the tray 2.

[0060] Preferably, the heat exchange relationship between the 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 heat exchange relationship between the part 16a and the thermal control means 6 can be achieved without the layer 17.

[0061] 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 arranged near the power elements and inside 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.

[0062] Each sensor management unit includes a measurement module that receives temperature, voltage and / or current measurements from the sensors 18 and a non-volatile memory module for storing information such as module identification data, overvoltage data, undervoltage data, overtemperature data, or the number of charge / discharge cycles.

[0063] The measurements from the sensors 18 can pass through a communication connector 15 (figure 3) connected to the sensor management units. Alternatively, the communication connector can comprise wall connectors capable of managing overpressure and temperature in the event of thermal runaway. Each master battery management unit determines for each power element 3 of the module a state of charge of the power element from the data provided by the associated sensor management units. Each master battery management unit is capable of carrying out load balancing operations on the power elements of the associated module.

[0064] Preferably, the master and high-level battery management units are integrated into the part 16a of the battery management system 16 located outside the containment structure described above. The sensor management units may also be arranged in the part 16a of the management system 16. Alternatively, it remains possible for the sensor management units to be placed as close as possible to the power elements 3, inside the containment structure.

[0065] The battery management units and the sensor management units arranged in the part 16a are integrated on an electronic card, preferably fixed to the plate 2 by second chemical and / or mechanical fixing means 19. For example, the second means 19 comprise columns and screw or bolt type fixings.

[0066] With reference to figure 3, the tray 2 comprises means for electrically connecting the battery, comprising a power connector 14 necessary to supply electrical current to the aircraft systems, as well as means for connecting communication means, comprising a communication connector 15 with the battery management system for diagnostic, control and / or regulation purposes.

[0067] Finally, the housing is preferably provided with first means for mechanically fixing the bell 5 on the plate 2, produced for example in the form of screws, bolts or any other fixing means appropriate for the intended use.

Claims

CLAIMS 1. Housing (1) for an electrical energy storage battery, comprising a tray (2) configured so that power elements (3) of the battery are fixed thereto, a bell (5) covering the tray (2), and means for mechanically fixing the bell (5) to the tray (2), the tray (2) comprising means for electrically connecting (14) the battery and means for thermally controlling (6) the power elements (3), characterized in that the tray and the bell constitute a structure for confining any thermal runaway of the power elements, said housing comprising a battery management system (16) of which at least one part (16a) is mounted outside the confinement structure and is in heat exchange relationship with the thermally controlling means (6) of the power elements (3).

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

3. Housing according to claim 1 or 2, in which 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. A 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, in which the thermal control means (6) of the power elements (3) comprise a temperature regulation circuit for said power elements.

8. Battery assembly for aircraft, 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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