Early detection and early warning method for thermal runaway of batteries in battery pack, thermosensitive barrier material and device

Abstract

The invention belongs to the technical field of fire fighting, and discloses an early detection and early warning method for thermal runaway of batteries in a battery pack, a thermosensitive barrier material and a device. According to the method, thermosensitive barrier materials are arranged among batteries in a battery pack and decomposed at a specific temperature to generate marking gas, the marking gas and combustible gas are detected by using an all-in-one gas detector, and a power management system and a fire extinguishing system are linked through a signal processing unit, so that graded early warning and early treatment are realized; a wide early warning window can be provided before thermal runaway of the battery, the battery pack has the advantages of low cost and long service life, and the safety performance of the battery pack is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the field of fire protection technology, and particularly relates to a method for early detection and warning of thermal runaway of batteries in a battery pack, a thermosensitive barrier material and a device. Background Art

[0002] In the first half of 2024, the newly installed power and energy scale of new energy storage both increased by 71% year-on-year. It is worth noting that the cumulative installed capacity of new energy storage exceeded 100 GWh for the first time, the power scale increased by 129% year-on-year, and the energy scale increased by 142% year-on-year. Lithium iron phosphate batteries have become the main choice for energy storage units in electrochemical energy storage due to their high safety, excellent electrochemical performance, long cycle life and environmental friendliness. However, in the context of the continuous increase in the energy density of lithium-ion batteries and the continuous expansion of the application scale, the safety problem of lithium-ion batteries has become one of the main technical bottlenecks restricting the development of electrochemical energy storage. In view of the characteristics of the fire in the electrochemical energy storage station, such as large combustion rate, rapid temperature rise, easy reignition and easy explosion, multiple fire cases show that the existing fire prevention and control technologies need to be improved urgently.

[0003] At present, there are mainly two kinds of safety monitoring means for lithium-ion batteries that have been applied in engineering: (1) When the battery is charging and discharging normally, the battery management system (BMS) is used in combination with traditional algorithms to detect the battery state, and monitor various battery states such as temperature, voltage, state of charge (SOC), etc.; (2) When the battery undergoes thermal runaway, the battery generates a large amount of heat and smoke and causes thermal spread in the energy storage system. The temperature sensors arranged in the system are used to detect the fixed-point temperature of the system, and the fire extinguishing device is linked to contain the thermal spread. A sensor with a certain sensitivity is used as the probe, and the external intuitive thermal runaway variables are processed by combining electronic components and a central processing unit, so as to carry out fire extinguishing.

[0004] The information required by the existing battery thermal runaway warning technology is usually obtained only after the lithium-ion battery opens the valve or undergoes thermal runaway. There are problems such as a narrow warning time window, short detector life, and high cost, resulting in that the thermally runaway battery cannot be identified and disposed of in time and effectively, and then thermal runaway spreads, ultimately causing disasters. At present, there is still a lack of technologies with low cost, long life and wide warning window, as well as devices and methods that can issue hierarchical warning signals before the battery undergoes thermal runaway. Summary of the Invention

[0005] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide a method for early detection and warning of thermal runaway of batteries in a battery pack, a thermosensitive barrier material and a device.

[0006] According to the embodiment of the present invention, the first solution is provided as follows:

[0007] An early detection and warning method for thermal runaway of batteries in a battery pack, comprising the following steps:

[0008] Arrange thermosensitive barrier materials between the batteries in the battery pack, and the thermosensitive barrier materials decompose to generate marker gases when the battery pack reaches a specific temperature;

[0009] Arrange a multi-gas detector in the battery pack to detect the marker gases and the combustible gases released after the battery safety valve is opened;

[0010] Process the signals sent by the multi-gas detector through a signal processing unit and transmit them to the power management system and the linkage device respectively;

[0011] The power management system and the linkage device perform corresponding disposal operations according to the received warning signals of different levels.

[0012] Further, when the concentration of the marker gas reaches the first threshold, the power management system controls the battery pack to reduce the output power, starts the cooling system to cool down, and triggers the first-level warning at the same time;

[0013] When the concentration of the marker gas reaches the second threshold, the power management system controls the battery pack to shut down, and triggers the second-level warning at the same time;

[0014] When the concentration of the combustible gas reaches the risk upper limit, the linkage device starts the fire extinguishing system and injects fire extinguishing agent into the battery pack;

[0015] When the linkage device starts the fire extinguishing system, the ventilation opening of the battery pack is closed at the same time to prevent oxygen from supporting combustion.

[0016] Further, the thermosensitive barrier material decomposes to generate marker gases when the temperature exceeds a specific temperature, and the marker gases are non-combustible gases;

[0017] The first threshold is 50% of the concentration of the marker gas, and the second threshold is 100% of the concentration of the marker gas.

[0018] The thermosensitive barrier material used in this solution is prepared by mixing aluminosilicate fiber, marker material and silicone resin, wherein the content of the marker material is 30-50wt% of the total weight of the thermosensitive barrier material;

[0019] The marker material decomposes to generate marker gases at a specific temperature, and the marker gases are non-combustible gases;

[0020] The thickness of the thermosensitive barrier material is 2-5mm.

[0021] Further, the marker material is selected from one or more of sodium bicarbonate and ammonium sulfate, and the marker gases include carbon dioxide and / or sulfur dioxide.

[0022] Further, the marking material includes two materials with different decomposition temperatures. The decomposition temperature of the first material is 70°C, releasing carbon dioxide; the decomposition temperature of the second material is 120°C, releasing sulfur dioxide.

[0023] Further, the preparation method includes: mixing the marking material with aluminosilicate fiber, adding silicone resin, and pressing and forming at 50°C followed by vacuum drying.

[0024] According to the embodiments of the present invention, using the method for early detection and warning of battery thermal runaway in the battery pack provided in the first solution of the present invention, the second solution is provided as follows:

[0025] An early detection and warning device for battery thermal runaway in a battery pack, comprising:

[0026] A thermosensitive barrier material, disposed on the side wall of the battery or between the batteries in the battery pack, decomposing at a specific temperature to generate a marking gas;

[0027] A multi-gas detector, disposed in the battery pack, for detecting the marking gas and the combustible gas released after the battery safety valve is opened;

[0028] A signal processing unit, connected to the multi-gas detector, for converting the detected gas concentration signal into an electrical signal;

[0029] A power management system, connected to the signal processing unit, for controlling the operating state of the battery pack according to the marking gas concentration;

[0030] A linkage device, connected to the signal processing unit, for controlling the activation of the fire extinguishing system according to the combustible gas concentration;

[0031] A fire extinguishing system, connected to the linkage device, for injecting a fire extinguishing agent into the battery pack through a filling port.

[0032] Further, the multi-gas detector can detect carbon dioxide, hydrogen, carbon monoxide, and volatile organic compounds, and the response time is less than 10 seconds.

[0033] Further, the power management system reduces the output power of the battery pack when the marking gas concentration reaches the first threshold, and controls the battery pack to shut down when the marking gas concentration reaches the second threshold;

[0034] The fire extinguishing system closes the ventilation port of the battery pack when starting to prevent oxygen from assisting combustion.

[0035] Compared with the prior art, the beneficial effects of the technical solution provided in this application.

[0036] By decomposing to generate marker gases before the thermal runaway of the battery through a thermosensitive barrier material, abnormal conditions can be detected in advance before the battery safety valve opens, significantly extending the early warning time window compared with traditional methods, facilitating timely power reduction or shutdown measures to avoid thermal runaway.

[0037] Trigger different levels of early warnings and response measures (such as power reduction, shutdown or fire extinguishing) according to different thresholds of the marker gas concentration (such as 50% and 100%), improving the flexibility and pertinence of disposal and being applicable to various application scenarios; By detecting and intervening in advance, the occurrence of battery thermal runaway is avoided to the greatest extent, ensuring the operation safety of the energy storage system.

[0038] The thermosensitive barrier material decomposes above 70°C to generate different non-combustible marker gases (such as carbon dioxide or sulfur dioxide), which can provide detectable signals even in the initial stage of battery thermal runaway or when the safety valve is not opened, significantly enhancing the early warning ability.

[0039] The marker gas is not only used for detection, but also can inert the environment inside the battery pack, reduce the explosion limit of combustible gases, and enhance the fire prevention performance of the barrier material.

[0040] The material has stable properties at room temperature, and the water generated by thermal decomposition can be absorbed by itself, improving the barrier performance; The optimization of the marker material content (30-50wt%) ensures the balance between decomposition efficiency and material strength.

[0041] By using marker materials with different decomposition temperatures (such as sodium bicarbonate at 70°C and ammonium sulfate at 120°C), hierarchical early warnings in multiple temperature ranges are realized, which are applicable to scenarios with different safety requirements.

[0042] Overcoming the problems of narrow technical window, short detector life and high cost of traditional thermal runaway early warning technologies, it provides an economical and efficient solution.

[0043] It is applicable to new energy storage systems, especially electrochemical energy storage stations, can effectively cope with the safety challenges brought by the increasing energy density, and promote the development of energy storage technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0045] Among them:

[0046] Figure 1 It is a structural block diagram of an early detection and warning device for battery thermal runaway in a battery pack in an embodiment.

[0047] Figure 2 It is a flowchart of a method for early detection and warning of thermal runaway of batteries in a battery pack in an embodiment.

[0048] Reference numerals:

[0049] 1. Single battery; 1-1. Safety valve; 2. Thermosensitive barrier material; 3. Battery pack; 4. Detector; 5. Signal processing unit; 6. Linkage device; 7. Fire extinguishing system; 8. Filling port; 9. Power management system. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0051] A method for early detection and warning of thermal runaway of batteries in a battery pack,

[0052] Arrange thermosensitive barrier materials between the batteries in the battery pack, and the thermosensitive barrier materials decompose to generate marker gas when the battery pack reaches a specific temperature;

[0053] Arrange a multi-gas detector in the battery pack to detect the marker gas and the combustible gas released after the battery safety valve is opened;

[0054] The signal processing unit processes the signals sent by the detector and transmits them to the power management system and the linkage device respectively;

[0055] When the marker gas reaches 50% of the threshold, the power management system controls the output power of the battery pack to decrease, and starts the air cooling or liquid cooling system of the battery pack to strengthen cooling; triggers a warning and notifies the operation and maintenance personnel to check.

[0056] When the marker gas reaches the threshold, the power management system controls the battery pack to shut down, triggers a warning, notifies the operation and maintenance personnel to troubleshoot and replace, and replace the thermosensitive barrier material.

[0057] When the concentration of the combustible gas reaches the risk upper limit, the linkage device starts the fire extinguishing system, and injects the fire extinguishing agent into the battery pack through the nozzle. At the same time, the ventilation opening of the battery pack is closed to prevent oxygen from assisting combustion.

[0058] The thermosensitive barrier material is stable in nature at normal temperature, decomposes to generate marker gas when the ambient temperature exceeds a specific temperature, and the marker gas is a gas that is easily detected by the detector.

[0059] The thermosensitive barrier material contains a marking material.

[0060] The marking gas generated by the thermosensitive barrier material when heated can not only be detected by the detector, but also be used for inerting inside the battery pack to reduce the explosion limit of combustible gases, thereby reducing the fire and explosion consequences caused by battery thermal runaway.

[0061] The water generated by the thermal decomposition of the thermosensitive barrier material can be absorbed by the thermosensitive barrier material itself, thereby improving the barrier performance of the thermosensitive barrier material.

[0062] The thermosensitive barrier material includes aluminosilicate fiber, a marking material and silicone resin, wherein the content of the marking material is 30-50 wt%; the marking material is one or more of sodium bicarbonate and ammonium sulfate; the thickness of the thermosensitive barrier material is 2-5 mm

[0063] The multi-gas detector can detect carbon dioxide, hydrogen, carbon monoxide and volatile organic compounds, and the response time is less than 10 seconds.

[0064] In a further improvement, the marking material is further optimized and set as two materials with different decomposition temperatures. In this way, different response measures and different warning messages can be taken for the battery pack in different temperature ranges, so that the flexibility of disposal is higher, and there will be more operation options for different application scenarios, especially applicable to the situation where it is not desired to open the battery valve, and even if the battery pack status is abnormal, the battery pack can still be used in stages.

[0065] Example 1

[0066] The preparation steps of a thermosensitive barrier material with a single-temperature marking gas include,

[0067] Mix sodium bicarbonate with aluminosilicate fiber and add silicone resin;

[0068] Aluminosilicate fiber: 40 wt%;

[0069] Marking material (sodium bicarbonate): 35 wt%;

[0070] Silicone resin: 25 wt%;

[0071] Press and form at 50 °C, and control the thickness at 2.5 mm;

[0072] Vacuum dry to remove moisture to obtain the required thermosensitive barrier material with a single-temperature marking gas.

[0073] The marking gas released by the thermosensitive barrier material with a single-temperature marking gas is carbon dioxide, and the specific release temperature is 70 °C.

[0074] Example 2

[0075] The preparation process is the same as that of Example 1, with the difference being that:

[0076] Aluminum silicate fiber: 30 wt%;

[0077] Marking material (sodium bicarbonate): 50 wt%;

[0078] Silicone resin: 20 wt%;

[0079] The pressing thickness is 3.5 mm.

[0080] Example 3

[0081] The preparation steps of the thermosensitive barrier material for multi-temperature marking gas include:

[0082] The production process is similar to that of the thermosensitive barrier material for single-temperature marking gas, with the difference being that

[0083] Aluminum silicate fiber: 30 wt%;

[0084] Marking material: 50 wt% (35 wt% sodium bicarbonate + 15 wt% ammonium sulfate, ratio 7:3);

[0085] Silicone resin: 20 wt%;

[0086] The thickness of the pressed and formed product is controlled at 5 mm.

[0087] The released marking gas is carbon dioxide, and the specific release temperature is 70 °C;

[0088] The released marking gas is sulfur dioxide, and the specific release temperature is 120 °C.

[0089] Using the above thermosensitive barrier material and the method for early detection and warning of battery thermal runaway in a battery pack, a device for early detection and warning of battery thermal runaway in a battery pack is designed in practical applications, including

[0090] A thermosensitive barrier material 2 provided on the side wall of the single cell 1 or between the single cells 1 in the battery pack 3;

[0091] A multi-gas detector 4 is provided in the battery pack 3, and the detector 4 is mainly responsible for detecting two types of gases, namely the marking gas and the combustible gas;

[0092] The marking gas includes carbon dioxide and sulfur dioxide, and the marking gas is released by the thermal decomposition of the thermosensitive barrier material 2 when it reaches the thermal decomposition temperature; the combustible gas includes hydrogen, carbon monoxide and VOC, and the combustible gas is generally released when the safety valve 1-1 of the battery thermal runaway is opened.

[0093] The multi-gas detector 4 is connected to the signal processing unit 5;

[0094] The signal processing unit 5 converts the gas concentration signal detected by the multi-gas detector 4 into an electrical signal and transmits it to the power management system 9 and the linkage device 6 connected thereto.

[0095] The power management system 9 controls the operation and output of the battery pack 3.

[0096] According to the set activation conditions, the linkage device 6 controls the activation of the fire extinguishing system 7 connected thereto and injects the fire extinguishing medium into the battery pack 3.

[0097] The fire extinguishing system 7 injects the fire extinguishing medium into the battery pack 3 through the injection port 8 provided on the battery pack 3.

[0098] Embodiment 3

[0099] The thermosensitive barrier material prepared in Embodiment 3 is filled in the battery gaps within a battery pack composed of 400 single 18650 batteries, and it is configured and installed according to a battery thermal runaway early detection and warning device.

[0100] By forcibly inducing a short circuit in the battery pack, during the monitoring of the battery pack in the experiment, the highest temperature point in the entire area of the battery pack is in the range of 70 - 75 °C. The power management system receives the first warning signal sent by the signal processing unit, restricts the output current of the battery pack, and blocks the continuous state of the short circuit.

[0101] During the further temperature rise of the battery pack, when the highest temperature point in the entire area of the battery pack reaches 125 °C, the power management system receives the second warning signal, cuts off the external power supply of the battery pack, and fully activates the circulating cooling system. Since no combustible gas released by the battery is detected, no fire extinguishing agent is injected. After 1.5 hours, the battery returns to room temperature. The battery pack is disassembled and inspected. None of the safety valves of the 18650 batteries are opened. However, during the destructive opening inspection of 25 randomly selected batteries, it is found that the diaphragms of 2 batteries in the central part of the battery pack have obvious shrinkage.

[0102] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0103] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for early detection and warning of thermal runaway of batteries in a battery pack, characterized in that, It includes the following steps: Arrange heat-sensitive barrier materials between the batteries in the battery pack. The heat-sensitive barrier materials decompose to produce marker gas when the battery pack reaches a specific temperature; Arrange a multi-gas detector in the battery pack to detect the marker gas and the combustible gas released after the battery safety valve is opened; Process the signals sent by the multi-gas detector through a signal processing unit and transmit them to the power management system and the linkage device respectively; The power management system and the linkage device perform corresponding disposal operations according to the received warning signals of different levels.

2. The method for early detection and warning of thermal runaway of batteries in a battery pack according to claim 1, wherein When the concentration of the marker gas reaches the first threshold, the power management system controls the battery pack to reduce the output power, starts the cooling system to cool down, and triggers a first-level warning at the same time; When the concentration of the marker gas reaches the second threshold, the power management system controls the battery pack to shut down and triggers a second-level warning at the same time; When the concentration of the combustible gas reaches the risk upper limit, the linkage device starts the fire extinguishing system and injects fire extinguishing agent into the battery pack; When the linkage device starts the fire extinguishing system, the ventilation opening of the battery pack is closed at the same time to prevent oxygen from supporting combustion.

3. The method for early detection and warning of thermal runaway of batteries in a battery pack according to claim 2, wherein The heat-sensitive barrier materials decompose to produce marker gas when the temperature exceeds a specific temperature, and the marker gas is non-combustible gas; The first threshold is 50% of the concentration of the marker gas, and the second threshold is 100% of the concentration of the marker gas.

4. A heat-sensitive barrier material for early detection and warning of thermal runaway of batteries in a battery pack, wherein The heat-sensitive barrier material is prepared by mixing aluminosilicate fiber, marker material and silicone resin, and the content of the marker material is 30-50wt% of the total weight of the heat-sensitive barrier material; The marker material decomposes to produce marker gas at a specific temperature, and the marker gas is non-combustible gas; The thickness of the heat-sensitive barrier material is 2-5mm.

5. The heat-sensitive barrier material according to claim 4, wherein The marker material is selected from one or more of sodium bicarbonate and ammonium sulfate, and the marker gas includes carbon dioxide and / or sulfur dioxide.

6. The heat-sensitive barrier material according to claim 4, wherein The marker material includes two materials with different decomposition temperatures. The decomposition temperature of the first material is 70°C, releasing carbon dioxide; the decomposition temperature of the second material is 120°C, releasing sulfur dioxide.

7. The thermosensitive barrier material according to claim 4, wherein The preparation method includes: mixing the marker material with aluminosilicate fiber, adding silicone resin, and pressing and forming at 50°C and then drying in vacuum.

8. An early detection and warning device for thermal runaway of batteries in a battery pack, characterized in that, It includes: Heat-sensitive barrier materials are arranged on the side walls of the batteries in the battery pack or between the batteries and decompose to produce marker gas at a specific temperature; A multi-gas detector is arranged in the battery pack to detect the marker gas and the combustible gas released after the battery safety valve is opened; A signal processing unit is connected to the multi-gas detector and is used to convert the detected gas concentration signal into an electrical signal; A power management system, connected to the signal processing unit, for controlling the operating state of the battery pack according to the concentration of the marker gas; An interlocking device, connected to the signal processing unit, for controlling the activation of the fire extinguishing system according to the concentration of the combustible gas; A fire extinguishing system, connected to the interlocking device, for injecting a fire extinguishing agent into the battery pack through the injection port.

9. The early detection and warning device for thermal runaway of batteries in a battery pack according to claim 8, wherein The multi-gas detector can detect carbon dioxide, hydrogen, carbon monoxide and volatile organic compounds, and the response time is less than 10 seconds.

10. The early detection and warning device for thermal runaway of batteries in a battery pack according to claim 8, wherein The power management system reduces the output power of the battery pack when the concentration of the marker gas reaches the first threshold, and controls the battery pack to shut down when the concentration of the marker gas reaches the second threshold; The fire extinguishing system closes the ventilation opening of the battery pack when starting to prevent oxygen from supporting combustion.

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