System for managing the safety of a battery and associated method

Abstract

The invention relates to a safety management system for managing the safety of a battery, the system comprising at least one module (1), characterised in that the module (1) comprises a cut-off relay (10) configured to open when the cut-off relay (10) is no longer being supplied with electric current, wherein the safety management system comprises an automaton (11) and a first power cabinet (12), wherein the first power cabinet (12) is connected to a safety device (16), wherein the first power cabinet (12) is configured to communicate with the control system of the battery (9) and with the cut-off relay (10) of the at least one module (1), wherein the first power cabinet (12) is configured to communicate with the gas sensor, and wherein the automaton (11) is connected to the cut-off relay (10) and to the safety device (16).

Description

BATTERY SAFETY MANAGEMENT SYSTEM AND ASSOCIATED METHOD

[0001] The invention relates to means of securing batteries.

[0002] Prior art patent application FR3134922, which describes a thermal regulation system for an automotive battery, is known. The thermal regulation system comprises a closed fluid network containing a liquid dielectric heat transfer fluid pumped by at least one pump. The fluid network includes at least one battery module. The module has an inlet and an outlet. The battery module includes electrical energy storage cells that are thermally regulated by partially filling the module with the heat transfer fluid. The thermal regulation system includes a control unit for monitoring the thermal regulation efficiency of the battery. Furthermore, the thermal regulation system incorporates a temperature sensing element within the module configured to communicate with the control unit.Thus, the operation of the thermal regulation system depends on the measured temperature and a predetermined target temperature. The thermal regulation system includes a heat transfer fluid heating device positioned upstream of the pump. The heating device is configured to activate upon command from the control unit when the measured temperature is lower than the predetermined target temperature. Finally, the fluid network includes a temperature sensing element positioned between the module's inlet and outlet to regulate the activation of the heating device based on the temperature measured in the fluid network. However, some drawbacks remain. In the event of a failure of the thermal regulation system, the coil is susceptible to thermal runaway, which can lead to damage or even ignition.

[0003] The objective of the present invention is to remedy these drawbacks and to secure the battery in order to limit the risks of thermal runaway and electrical risks.

[0004] To achieve this objective, the invention proposes a battery safety management system comprising at least one module, said module comprising a plurality of electrochemical cells connected in series or parallel, the cells comprising at least one gas, said battery comprising a cooling circuit comprising a dielectric fluid suitable for circulating in said module, a cooling system configured to cool said dielectric fluid and a transfer pump configured to generate the circulation of said dielectric fluid, said module comprising an inlet and an outlet, said cooling circuit comprising a first manifold connected to said inlet and a second manifold connected to said outlet, the first manifold being configured to direct said dielectric fluid into said module through said inlet,the second collector being configured to collect said dielectric fluid by said outlet and to direct said dielectric fluid to said cooling system, said cells being immersed in said dielectric fluid, said second collector being capable of collecting said gas, said module comprising a temperature sensor and a voltage sensor, said module comprising a battery control system configured to communicate with said temperature sensor and voltage sensor, notable in that said module comprises a cutoff relay, said safety management system comprising a PLC and a first power cabinet, said first power cabinet being configured to supply electrical current to the cutoff relay, said cutoff relay being capable of closing to allow electrical current to flow through said module or opening to electrically isolate said module,the cutoff relay being configured to open when said cutoff relay is no longer supplied with electrical current, said first power cabinet being supplied with electrical current via an electrical outlet, said first power cabinet being connected to a safety device, said first power cabinet being configured to communicate with the battery control system and said cutoff relay from said at least one module, said PLC being connected to the cutoff relay and the safety device, the cutoff relay being connected to the safety device.

[0005] Thanks to the invention, the battery offers improved safety. The risks of thermal runaway and electrical hazards are reduced.

[0006] Advantageously, said second manifold includes a gas sensor, the first power cabinet being configured to communicate with said gas sensor.

[0007] Alternatively, said module having a vent configured to vent said gas, said battery having a third collector connected to the vent, said third collector having a gas sensor, the first power cabinet being configured to communicate with said gas sensor.

[0008] Preferably, said gas sensor is a dihydrogen sensor or a carbon monoxide sensor.

[0009] Advantageously, said automaton is connected to a warning device configured to inform a user of the safety status of said battery, preferably an alarm or a display device.

[0010] This allows people in the vicinity of the battery to be warned of a risk.

[0011] Preferably, said module includes a fuse, said fuse being configured to interrupt the flow of electric current in said module when the voltage sensor is above a predetermined threshold voltage.

[0012] The fuse provides an additional safety measure by cutting off the electrical current when the cutoff relay malfunctions.

[0013] Advantageously, said battery includes a heating device configured to warm said cells.

[0014] In this way, the cells maintain an optimal operating temperature. This improves the lifespan of these cells.

[0015] Preferably, the safety device is an immersion sensor.

[0016] Preferably, said battery contains lithium, iron and phosphate.

[0017] Such a battery exhibits high thermal stability, a long lifespan and tolerance to extreme temperatures, reducing the risk of damage in the event of fire or explosion.

[0018] Furthermore, the invention relates to a method of securing a battery by the previously described safety management system, remarkable in that said method comprises the following steps: - a step of detection by the battery control system of a temperature greater than a first threshold value predetermined by the temperature sensor and / or of a gas concentration greater than a second threshold value predetermined by a gas sensor positioned on the second or third collector, and / or a step of detection of an event likely to damage the battery by the safety device; - a step of actuation of the transfer pump controlled by a PLC communicating with the battery control system when the temperature is greater than said first predetermined threshold value;- a step of interrupting the power supply to the cut-off relay by the PLC when the temperature remains above said first predetermined threshold value following the actuation step of the transfer pump and / or when the gas concentration is above the second predetermined threshold value and / or when the safety device detects an event likely to damage the battery.

[0019] This process allows the battery to be isolated when it overheats, when gas accumulates within it, or when a hazard related to an external condition is detected. This improves the safety of people present around the battery.

[0020] Advantageously, the module includes a fuse, the method comprising a step of interrupting the flow of electric current in the module by the fuse when the cutoff relay malfunctions so that the cutoff relay is constantly closed.

[0021] Preferably, said battery includes a heating device configured to warm said cells, said method including a step of heating said cells by said heating device when the temperature sensor measures a temperature below a predetermined minimum temperature.

[0022] Advantageously, the process is implemented on a marine vehicle, said safety device being an immersion sensor of the marine vehicle, said immersion sensor being configured to emit a signal when said immersion sensor is immersed in a liquid.

[0023] The invention also relates to a land or sea vehicle comprising said battery safety management system previously described, said safety management system being configured to implement the battery safety method previously described.

[0024] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the attached figures illustrating variants of the invention, in which: schematically illustrates a battery safety management system according to an embodiment of the invention; schematically illustrates a battery module of the battery safety management system illustrated in.

[0025] A battery safety management system is schematically illustrated in Figure 1 according to one embodiment of the invention. The battery comprises a plurality of modules 1. For example, in Figure 1, the safety management system comprises three modules 1. In another embodiment, the battery comprises a single module. Module 1 comprises a plurality of electrochemical cells 2 containing at least one gas. Each cell 2 has a positive terminal and a negative terminal. The cells 2 are connected in series or in parallel. When connected in series, the cells 2 are connected end-to-end such that the positive terminal of one cell 2 is connected to the negative terminal of the next cell 2. When connected in parallel, the positive terminals of each cell 2 are connected together. The same applies to the negative terminals of each cell 2.Module 1 includes a temperature sensor (not shown) and a voltage sensor (not shown). Module 1 includes a battery control system 9 configured to communicate with the temperature and voltage sensors. In addition, Module 1 includes a disconnect relay 10 configured to electrically isolate Module 1. The disconnect relay 10 is configured to close to allow current to flow or to open to interrupt the flow of current. The disconnect relay 10 is configured to open, i.e., to interrupt the flow of current, when the disconnect relay 10 is no longer energized. Preferably, the disconnect relay 10 includes at least one coil and contacts. The contacts are responsible for closing the electrical circuit when the coil is energized or opening the electrical circuit when the coil is de-energized.Preferably, module 1 includes a fuse 18 to interrupt the flow of electric current when the voltage measured by the voltage sensor exceeds a predetermined threshold voltage. Furthermore, the battery includes a cooling circuit for module 1. The cooling circuit includes a dielectric fluid 3 configured to circulate within module 1(s). Preferably, this dielectric fluid 3 is a biodegradable fluid such as a product from the MIVOLT® brand. Biodegradable products decompose naturally into non-toxic elements, thus avoiding contributing to the accumulation of waste in the environment. The cooling circuit also includes a cooling system configured to cool this dielectric fluid 3 and a transfer pump configured to allow the circulation of this dielectric fluid 3 within the battery.As shown in the figure, module 1 has an inlet 4 and an outlet 5. The dielectric fluid 3 is able to circulate between said inlet 4 and said outlet 5 of module 1. The cells 2 are immersed in the dielectric fluid 3. The cooling circuit has a first manifold (not shown) connected to said inlet 4. The first manifold is configured to direct said cold dielectric fluid 3 into said module 1 in order to cool the cells 2 inside said module 1. In addition, the cooling circuit has a second manifold (not shown) connected to said outlet 5. The second manifold is configured to collect said hot dielectric fluid 3 from the outlet 5 of module 1 and to direct said hot dielectric fluid 3 to said cooling system. In addition, the second manifold is able to collect said gas emitted by the cells 2 in the event of outgassing from them.Thus, the dielectric fluid 3 is cooled by the cooling system before being reinjected into the first collector. Optionally, the battery includes a heating device configured to warm the cells 2 when the temperature sensor measures a temperature below a predetermined minimum temperature. This maintains the battery at an optimal temperature, thereby improving its lifespan. The optimal temperature is between 10°C and 30°C. The battery temperature must remain below 50°C. Preferably, the battery has a voltage between 10V and 100V. The nominal voltage of the battery is 51V. Preferably, the battery contains lithium iron phosphate. It is a type of rechargeable battery with an iron phosphate cathode and a lithium anode.Such a battery exhibits high thermal stability and resistance to fire and explosion hazards, making it safer than other battery types, such as lithium-ion batteries. Furthermore, the lithium-iron-phosphate battery offers a long lifespan and tolerance to extreme temperatures. Optionally, the second manifold includes a gas sensor. Preferably, the second manifold includes an expansion tank with the gas sensor. The expansion tank absorbs volume variations in the dielectric fluid due to temperature and maintains pressure in the cooling circuit. It prevents leaks caused by potential overpressure. In addition, the second manifold preferably includes a pressure sensor and / or a level sensor capable of measuring the fluid level in the second manifold.Alternatively, the battery includes a third collector 6 configured to collect said gas via a vent 7. The vent 7 allows the gas accumulating in said module 1 to be vented to said third collector 6. The third collector 6 includes a gas sensor 8. For example, the gas sensor could be a hydrogen sensor or a carbon monoxide sensor. The gas sensor could also be a pollution sensor, also known as a PM2.5 sensor, or a smoke sensor. The smoke sensor is, for example, an optical sensor. The optical sensor operates via a light source and a photodetector capable of measuring changes in the light from the light source due to scattering or absorption by smoke particles. In addition, said safety management system includes a programmable logic controller (PLC) 11 and a first power cabinet 12.The first power cabinet 12 is configured to supply electrical current to the cutoff relay 10 and to communicate with the battery control system 9 and the previously mentioned gas sensor 8. Communication between the various components is ensured either by wired or wireless communication devices. The different communication methods are illustrated by dashed lines on the diagram. The solid lines shown in the diagram illustrate the electrical connections between the different components of the safety management system. The first power cabinet 12 is itself supplied with electrical current via a power outlet 13 through a second power cabinet 14 and a charger 15. The second power cabinet 14 may include voltage converters. The role of the charger 15 is to regulate the voltage or current.The first power cabinet 12 is connected, preferably via a wired connection, to a safety device 16. The safety device 16, as defined in the present invention, is a device capable of detecting an event that could lead to battery damage, the damage itself being likely to endanger people in the vicinity of said battery. The safety device 16 is designed to prevent battery damage by detecting upstream an event likely to damage it. For example, in the case of batteries stored on the ground in the open air, the safety device 16 is a sensor that detects when said battery is opened. Opening the battery is an event likely to lead to battery damage because said battery is then exposed to a risk of short circuit if it rains, for example.The safety device 16 is configured to control the electrical isolation of the battery module(s) 1 to prevent damage to the battery. The controller 11 is a device capable of communicating with the disconnect relay 10 and with the safety device 16. Preferably, the controller 11 is connected to a control device 19 and a warning device 17. The control device 19 is an interface between the battery safety management system and people around the battery. For example, if a user wishes to perform maintenance on the battery, they can configure the safety management system so that the battery poses no danger to them. In other words, it is possible to manually isolate the battery from the control device 19 to prevent the risk of electric shock to users.The warning device 17 is present to alert a user to the battery's safety status. Thus, in the event of an electrical hazard, the user(s) are warned by said warning device 17. For example, the warning device 17 is a display device such as a digital screen or an alarm. It is also possible that the warning device 17 may be capable of automatically calling emergency services, for example, the fire department, if necessary. The safety management system is implemented in a vehicle. This can be any vehicle capable of movement, with or without human assistance. The first power cabinet 12 supplies an electric motor 20 of said vehicle via a variable frequency drive 21. The role of the variable frequency drive 21 is to regulate the rotational speed of the electric motor 20 by varying the frequency and voltage supplied to said electric motor 20.The motor is a consumer of electrical current. This is a non-limiting example. Alternatively, the motor could be replaced by a DC / AC converter (acronym meaning Direct Current / Alternating Current), for example.

[0026] Furthermore, the invention relates to a method for securing the battery using the previously described safety management system. During a detection step, the battery control system 9 detects a temperature exceeding a first predetermined threshold value set by the temperature sensor and / or, when the second or third collector includes a gas sensor, a gas concentration exceeding a second predetermined threshold value set by said gas sensor 8. When the high temperature and / or high gas concentration is detected, the information is transmitted to the controller 11. The safety device 16 can also detect an event likely to cause damage to the battery. During a step involving the actuation of the transfer pump by said controller 11, when the temperature exceeds said first predetermined threshold value set during the previous detection step.Indeed, if module 1 reaches a temperature that could lead to deterioration, explosion, or fire, the cooling circuit transfer pump activates to circulate the dielectric fluid 3. This lowers the temperature of module 1. If the temperature remains above the first predetermined threshold value despite the activation of the transfer pump during the transfer pump activation step, the controller 11 commands a power cut-off to the module 1 cut-off relay 10 during a power cut-off relay 10 interruption step in order to electrically isolate module 1 and prevent a temperature increase, and consequently thermal runaway, of module 1.Similarly, the control unit 11 interrupts the power supply to the cutoff relay 10 when the gas concentration exceeds the second predetermined threshold value and / or when an event likely to damage the battery is detected by the safety device 16. Indeed, the accumulation of gas in the second or third collector 6 indicates a gas leak at the electrochemical cells 2. Since the gas is flammable and potentially toxic, it is necessary to isolate module 1 to prevent a potential explosion and / or poisoning of nearby people.When said module 1 includes the fuse 18, the process optionally includes a step of interrupting the flow of electric current by said fuse 18 when the cut-off relay 10 is still energized despite the control of the controller 11, that is to say, despite the temperature of module 1 remaining above said first predetermined threshold value, the gas concentration being above the second predetermined threshold value, or said external risk being detected by said safety device 16. Thus, in the event of a malfunction of the cut-off relay 10, which fails to open, the fuse 18 provides additional safety by cutting off the electric current instead of the cut-off relay 10.Furthermore, if the temperature measured inside module 1 by the temperature sensor, during the detection stage, undergoes a sudden change, for example from 5°C to 30°C in less than ten minutes, a warning may be issued by said warning device 17, without necessarily triggering the transfer pump.

[0027] When the battery is used for a marine vehicle, for example, a ship, the safety device 16 is preferably an immersion sensor configured to send a signal to the controller 11 when said immersion sensor is immersed in a liquid, for example, water. For example, the immersion sensor includes a float to measure the water level in a container positioned so that said container only fills with water in the event of a shipwreck. In this alternative, during the detection stage, the event likely to damage the battery is the shipwreck. The electrical isolation of the battery module(s) 1 in this case prevents the risk of electrocution of persons on board the ship. The controller is configured to communicate with said immersion sensor. Communication can be ensured via a wired connection, for example. The immersion sensor can also be used outside of a marine vehicle.In this application, the electrical outlet 13 supplying power to the first power cabinet 12 is a shore power outlet. A shore power outlet, also known as an earth connection, is an electrical device installed on port docks to provide electricity to maritime vehicles when they are docked.

[0028] The invention also relates to a land or sea vehicle comprising a battery safety management system configured to implement the battery safety method described above.

Claims

Battery safety management system comprising at least one module (1), said module (1) comprising a plurality of electrochemical cells (2) connected in series or in parallel, the cells (2) comprising at least one gas, said battery comprising a cooling circuit comprising a dielectric fluid (3) suitable for circulating in said module (1), a cooling system configured to cool said dielectric fluid (3) and a transfer pump configured to generate the circulation of said dielectric fluid (3), said module (1) comprising an inlet (4) and an outlet (5), said cooling circuit comprising a first manifold connected to said inlet (4) and a second manifold connected to said outlet (5), the first manifold being configured to direct said dielectric fluid (3) into said module (1) through said inlet (4),the second collector being configured to collect said dielectric fluid (3) by said outlet (5) and to direct said dielectric fluid (3) to said cooling system, said cells (2) being immersed in said dielectric fluid (3), said second collector being capable of collecting said gas, said module (1) comprising a temperature sensor and a voltage sensor, said module (1) comprising a battery control system (9) configured to communicate with said temperature sensor and voltage sensor, characterized in that said module (1) comprises a cutoff relay (10), said safety management system comprising a PLC (11) and a first power cabinet (12), said first power cabinet (12) being configured to supply electrical current to the cutoff relay (10),said disconnect relay (10) being capable of closing to allow electric current to flow through said module (1) or of opening to electrically isolate said module (1), the disconnect relay (10) being configured to open when said disconnect relay (10) is no longer supplied with electric current, said first power cabinet (12) being supplied with electric current by an electrical outlet (13), said first power cabinet (12) being connected to a safety device (16), said first power cabinet (12) being configured to communicate with the battery control system (9) and said disconnect relay (10) of said at least one module (1), said PLC (11) being connected to the disconnect relay (10) and to the safety device (16), the disconnect relay (10) being connected to the safety device (16). System according to claim 1 characterized in that said second manifold comprises a gas sensor, the first power cabinet (12) being configured to communicate with said gas sensor. System according to claim 1 characterized in that said module (1) comprising a vent (7) configured to vent said gas, said battery comprising a third collector (6) connected to the vent (7), said third collector (6) comprising a gas sensor (8), the first power cabinet (12) being configured to communicate with said gas sensor (8). System according to claim 2 or 3 characterized in that said gas sensor is a dihydrogen sensor or a carbon monoxide sensor. System according to any one of claims 1 to 4 characterized in that said automaton (11) is connected to a warning device (17) configured to inform a user of the safety status of said battery, preferably an alarm or a display device. System according to any one of claims 1 to 5 characterized in that said module (1) comprises a fuse (18), said fuse (18) being configured to interrupt the flow of electric current in said module (1) when the voltage sensor is above a predetermined threshold voltage. System according to any one of claims 1 to 6, characterized in that the safety device (16) is an immersion sensor. A method for securing a battery by means of the safety management system according to any one of claims 1 to 7, characterized in that said method comprises the following steps: - a step of detection by the battery control system (9) of a temperature greater than a first threshold value predetermined by the temperature sensor and / or of a gas concentration greater than a second threshold value predetermined by a gas sensor (8) positioned on the second collector or on the third collector (6), and / or a step of detection of an event likely to damage the battery by the safety device (16); - a step of actuation of the transfer pump controlled by a controller (11) communicating with the battery control system (9) when the temperature is greater than said first predetermined threshold value;- a step of interrupting the power supply to the cut-off relay (10) by the PLC (11) when the temperature remains above said first predetermined threshold value following the actuation step of the transfer pump and / or when the gas concentration is above the second predetermined threshold value and / or when the safety device (16) detects an event likely to damage the battery. ; Method according to claim 8 characterized in that the module (1) comprises a fuse (18), said method comprising a step of interrupting the flow of electric current in said module (1) by said fuse (18) when the cutoff relay (10) malfunctions so that said cutoff relay (10) is constantly closed. Method according to claim 8 or 9 characterized in that the method is implemented on a marine vehicle, said safety device (16) being an immersion sensor of the marine vehicle, said immersion sensor being configured to emit a signal when said immersion sensor is immersed in a liquid.

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