Assembly comprising a battery and an emergency system, and associated method
A pressurized fluid emergency system for vehicle batteries addresses thermal runaway by spraying vaporized fluid to cool and freeze the battery, effectively preventing fire spread without adding weight, thus meeting fire safety and roadworthiness standards.
Patent Information
- Application Number
- FR2024006617
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2024-06-20
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-06-20
AI Technical Summary
High-power vehicle batteries pose a fire risk due to thermal runaway, which can spread throughout the battery and surrounding components, necessitating heavy fluid immersion for extinguishing, impractical for vehicle implementation.
A pressurized fluid emergency system that remains isolated from the battery in normal operation but connects to spray vaporized fluid onto the battery during thermal runaway, using a refrigeration circuit to cool and potentially freeze the battery.
Effectively limits thermal runaway without significantly increasing vehicle weight by using a compact emergency system that vaporizes and sprays fluid to cool or freeze the battery, preventing fire propagation.
Smart Images
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Abstract
Description
Title of the invention: Assembly comprising a battery and an emergency system, and associated method
[0001] The present invention relates to an assembly comprising a battery with an emergency system and an associated method.
[0002] When using batteries in a vehicle, the use of high-power batteries can pose a risk to passengers in the event of a fire. For example, if a battery cell malfunctions, thermal runaway may occur. The battery's architecture can trigger a chain reaction, propagating the thermal runaway from one cell to surrounding cells. Thus, if a cell experiences thermal runaway, the heat can spread throughout the entire battery until it is completely destroyed, along with its surrounding components, or until emergency services intervene.
[0003] Fire safety and vehicle roadworthiness standards require the implementation of specific upstream measures to address the risk of battery fires, in order to protect persons in the vehicle. However, the occurrence of such an event must still be taken into account.
[0004] Today, to extinguish a Lithium battery fire and stop the associated thermal runaway, one solution would be, for example, to immerse the battery in a fluid.
[0005] However, implementing such a technology on a battery embedded in a vehicle requires the storage of a very large volume of fluid, which is too heavy, for this solution to be implemented in a vehicle.
[0006] The aim of the invention is therefore to propose a system to limit the risk of thermal runaway, which can be implemented in a vehicle.
[0007] For this purpose, the invention relates to an assembly comprising a vehicle battery and an emergency system, the emergency system having an operational mode of operation and an emergency mode, the emergency system containing a pressurized fluid in the operational mode of operation, the pressurized fluid not communicating fluidly with the battery in the operational mode of operation, the emergency system being fluidly connected to the battery in the emergency mode so as to spray the fluid onto the battery, the fluid then being vaporized between the emergency system and the battery.
[0008] Vaporizing the fluid under pressure lowers its temperature, resulting in efficient cooling of the battery, for example up to the freezing of the battery, without requiring as much fluid as immersing the battery.
[0009] According to other advantageous aspects of the invention, the assembly comprises one or more of the following features, taken individually or in all technically possible combinations:
[0010] - the battery includes a casing containing battery cells, the system emergency being adapted to spray the fluid directly inside the casing;
[0011] - the emergency system includes a tap having an open configuration and a closed configuration, the tap being in the open configuration in emergency mode and in the closed configuration in operational mode;
[0012] - the valve is adapted to relieve the pressurized fluid passing through it by open configuration;
[0013] - the emergency system includes a refrigeration circuit containing the fluid under pressure, more specifically from a heating, ventilation and air conditioning system or a battery thermal management system;
[0014] - the fluid is suitable for being drawn from the refrigeration circuit at a point of sampling, preferably equipped with a valve;
[0015] - the refrigeration circuit includes a buffer tank;
[0016] - the refrigeration circuit includes a compressor and / or at least one expansion valve of the pressurized fluid; and / or
[0017] - the emergency system includes spray nozzles adapted for spraying the fluid on the battery.
[0018] The invention also relates to a method for limiting the thermal runaway of a battery, comprising the following steps:
[0019] - supply of an assembly as defined above, the emergency system operating according to the operational mode,
[0020] - detection of thermal runaway within the battery, and
[0021] - activation of the emergency system in emergency mode, the vaporized fluid being sprayed onto the battery.
[0022] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the following drawing:
[0023] [Fig-1] [Fig.1] is a schematic representation of an example assembly according to an embodiment of the invention.
[0024] The invention relates to an assembly 10 comprising a vehicle battery 12, more particularly a railway vehicle battery, and an emergency system 14.
[0025] The battery 12 here comprises a case 16 containing battery cells.
[0026] The emergency system 14 has an operational mode of operation and an emergency mode.
[0027] The emergency system 14 includes a container 18 for pressurized fluid, for example carbon dioxide.
[0028] The fluid is, for example, in liquid form in the container 18.
[0029] The fluid has, for example, a pressure between 5 bars and 15 bars.
[0030] Container 18 comprises, for example, between 10 and 100 kilograms of carbon dioxide.
[0031] This makes it possible to compensate at least in part for the energy released by the cells in the event of thermal runaway, without significantly increasing the weight of the vehicle.
[0032] The emergency system 14 includes, for example, a refrigeration circuit 20 containing the pressurized fluid, forming here the container 18, more particularly the refrigeration circuit of a heating, ventilation and air conditioning system 22 (called HVAC) or of a battery thermal management system (called BTMS).
[0033] In the embodiment shown, the refrigeration circuit 20 includes, for example, a buffer tank 24.
[0034] The buffer tank 24 is here a local enlargement of the refrigeration circuit line.
[0035] This allows the refrigeration circuit to contain more fluid than without the expansion. This also reduces the impact on HVAC performance in the event of a leak, and thus increases maintenance intervals.
[0036] The refrigeration circuit 20 includes, here, a compressor 26 and / or at least one expansion valve 28 of the pressurized fluid, here a compressor 26 and an expansion valve 28 of the pressurized fluid.
[0037] The compressor 26 compresses the fluid circulating in the refrigeration circuit.
[0038] This results in a rise in the temperature of said fluid.
[0039] The expansion valve 28 reduces the pressure of the fluid circulating in the refrigeration circuit.
[0040] This results in a drop in the temperature of said fluid.
[0041] A direction of fluid flow in the refrigeration circuit is defined.
[0042] From the compressor 26 to the expansion valve 28 along the flow direction, extends the condenser.
[0043] From the expansion valve 28 to the compressor along the flow direction, extends the evaporator.
[0044] The fluid has a temperature strictly greater than -10°C throughout the entire refrigeration circuit.
[0045] Alternatively, the emergency system includes a simple tank containing the fluid, here carbon dioxide, under pressure.
[0046] The pressurized fluid does not communicate fluidly with the battery 12 in the operational mode, that is to say that the container, here the refrigeration circuit or the tank, does not communicate fluidly with the battery 12 in the operational mode.
[0047] In emergency mode, the emergency system 14 is fluidically connected to the battery 12 so as to spray the fluid onto the battery 12, more particularly directly inside the housing 16, the fluid being vaporized between the emergency system 14 and the battery 12, resulting, for example, in the battery 12 freezing.
[0048] More particularly, the battery 12 is fluidically connected to the container 18 by a fluidic line 30.
[0049] The fluid is, for example, taken from the refrigeration circuit 20 or from the tank at a sampling point 32, for example equipped with a valve 33.
[0050] In the example above, the sampling point 32 is arranged downstream of the regulator 28, and here upstream of the compressor 26.
[0051] The sampling point 32 is arranged at the level of the condenser.
[0052] The valve 33 has an open configuration, in which fluid is able to pass through the valve, and a closed configuration, in which fluid cannot pass through the valve.
[0053] The emergency system 14 here includes a valve 34 having an open configuration, in which fluid is able to pass through the valve, and a closed configuration, in which fluid cannot pass through the valve.
[0054] The valve 34 is arranged on the fluidic line 30.
[0055] The valve 34 is adapted to relieve pressure on the fluid passing through it. open configuration.
[0056] The fluid passing through the tap 34 has, for example, a fixed flow rate within 5%.
[0057] The emergency system 14 further comprises adapted spray nozzles 36 to spray the fluid onto battery 12.
[0058] The spray nozzles 36 extend downstream of the fluidic line 30.
[0059] More specifically, the spray nozzles 36 are arranged so that spray the fluid inside the housing 16, onto the battery cells 12.
[0060] The 36 spray nozzles are distributed over the entire battery.
[0061] The spray nozzles 36 are adapted to expand the fluid passing through them.
[0062] More particularly, after spraying through the spray nozzles 36, in particular here after passing through the tap 34 and then the spray nozzles 36, the fluid is at the ambient pressure of the battery.
[0063] The spray nozzles 36 are adapted to reduce the pressure of the fluid passing through them, for example, by at least 1 bar, more particularly by at least 3 bars, here between 3 and 6 bars.
[0064] In the operational mode of the emergency system, the pressurized fluid is contained in said emergency system, here in the container 18, for example within the refrigeration circuit 20 or the tank.
[0065] The pressurized fluid has a temperature strictly greater than 0°C.
[0066] The tap 34 is in the closed configuration.
[0067] The container 18 does not communicate fluidly with the battery 12.
[0068] In emergency mode, the container 18 communicates smoothly with the battery 12.
[0069] The pressurized fluid is taken from the sampling point 32 and sprayed onto the battery, more particularly inside the housing 16.
[0070] Here, the refrigeration circuit drains inside battery 12.
[0071] Here, tap 34 is in the open configuration in emergency mode.
[0072] More specifically, in emergency mode, the pressurized fluid exits the container 18 through the sampling point 32, and passes through the valve 34.
[0073] During its passage through the valve 34, the fluid undergoes expansion. This results in the fluid cooling, for example to a temperature strictly below -50°C for carbon dioxide.
[0074] The fluid then reaches the spray nozzles 36, which spray it onto the battery 12, more particularly inside the housing 16.
[0075] The spraying results in an immediate expansion of the fluid, which is vaporized.
[0076] The fluid then exchanges heat with the battery, which cools, or even freezes, the battery.
[0077] The fluid draws energy in the form of heat from the battery.
[0078] The quantity of pressurized fluid carried on board makes it possible to compensate for the energy released by at least all of the cells.
[0079] This helps to prevent the spread of thermal runaway.
[0080] A method for limiting the thermal runaway of a battery will now be described, with regard to the assembly described previously.
[0081] The process comprises the following steps:
[0082] - supply of a set described above, the emergency system 14 operating according to the operational mode,
[0083] - detection of thermal runaway within battery 12, and
[0084] - activation of emergency system 14 in emergency mode, the vaporized fluid being sprayed on battery 12.
[0085] The detection of thermal runaway within the battery 12 is carried out by local detection of an abnormal temperature rise, in particular by means of dedicated sensors, for example temperature probes, such as a linear heat detector (or LHD from the English "Linear heat detection").
[0086] Such detection automatically causes a change in the operation of the emergency system from operational mode to emergency mode.
[0087] The pressurized fluid is vaporized and sprayed onto battery 12 in accordance with what has been described previously.
[0088] This makes it possible to dissipate the energy released by the battery cells, particularly those affected by thermal runaway.
[0089] The fluid draws energy in the form of heat from the battery.
[0090] This therefore makes it possible to limit or even stop the thermal runaway of the battery, so as to avoid the propagation and a possible fire.
Claims
Demands
1. Assembly (10) comprising a vehicle battery (12) and an emergency system (14), the emergency system (14) having an operational mode of operation and an emergency mode, the emergency system (14) containing a pressurized fluid in the operational mode of operation, the pressurized fluid not communicating fluidly with the battery (12) in the operational mode of operation, the emergency system (14) being fluidly connected to the battery (12) in the emergency mode so as to spray the fluid onto the battery (12), the fluid then being vaporized between the emergency system (14) and the battery (12).
2. Assembly according to claim 1, wherein the battery (12) comprises a case (16) containing battery cells, the emergency system (14) being adapted to spray the fluid directly inside the case (16).
3. Assembly according to claim 1 or 2, wherein the emergency system (14) comprises a valve (34) having an open configuration and a closed configuration, the valve (34) being in the open configuration in emergency mode and in the closed configuration in operational mode.
4. Assembly according to claim 3, wherein the valve (34) is adapted to relieve the pressurized fluid passing through it in open configuration.
5. Assembly according to any one of claims 1 to 4, wherein the emergency system (14) comprises a refrigeration circuit (20) containing the pressurized fluid, more particularly from a heating, ventilation and air conditioning system (22) or a battery thermal management system.
6. Assembly according to claim 5, wherein the fluid is able to be taken from the refrigeration circuit (20) at a sampling point (32), preferably equipped with a valve (33).
7. Assembly according to claim 5 or 6, wherein the refrigeration circuit (20) includes a buffer tank (24).
8. Assembly according to any one of claims 5 to 7, wherein the refrigeration circuit (20) comprises a compressor (26) and / or at least one expansion valve (28) of the pressurized fluid.
9. Assembly according to any one of claims 1 to 8, wherein the emergency system (14) includes spray nozzles (36) adapted to spray the fluid onto the battery (12).
10. Method for limiting thermal runaway of a battery (12), comprising the following steps: - providing an assembly (10) according to any one of claims 1 to 9, the emergency system (14) operating in the operational mode, - detecting thermal runaway within the battery (12), and - activating the emergency system (14) in emergency mode, the vaporized fluid being sprayed onto the battery (12).