Thermal runaway flue gas treatment device

Abstract

The utility model provides a thermal runaway flue gas treatment device which mainly solves the problem that potential safety hazards exist when thermal runaway flue gas is discharged out of a battery shell. The thermal runaway flue gas treatment device comprises a liquid treatment device and a gas generation device, the liquid treatment device comprises at least one liquid treatment tank, the liquid treatment tank is provided with a flue gas inlet and a flue gas outlet which are communicated with an inner cavity of the liquid treatment tank, the liquid treatment tank is filled with a liquid treatment medium, the liquid treatment medium is mainly used for treating electrolyte in thermal runaway flue gas, and the gas generation device is used for generating flame-retardant gas. And the flame-retardant gas and the thermal runaway flue gas treated by the liquid treatment device are mixed, so that the proportion of combustible gas in the mixed gas is greatly reduced, combustion or explosion is difficult to occur after the mixed gas is in contact with air, and the problem of potential safety hazards caused by the fact that the thermal runaway flue gas is discharged out of the battery shell is solved.

Description

Technical Field

[0001] The utility model belongs to the field of batteries, and in particular relates to a thermal runaway flue gas treatment device. Background Art

[0002] With the widespread application of lithium-ion batteries, the safe use of lithium-ion batteries has also attracted attention. Under the influence of factors such as overcharge, overdischarge, overheating, and mechanical collision, lithium-ion batteries are prone to battery diaphragm collapse and internal short circuit, leading to thermal runaway.

[0003] When a lithium battery is in complete thermal runaway, the internal temperature of the battery is as high as 500-1000℃. The gas generated during the thermal runaway process causes the internal pressure of the battery to increase, causing the battery shell to expand and rupture, and eventually the explosion venting membrane opens, spraying and releasing the evaporated electrolyte and reaction gas inside the battery, forming thermal runaway smoke. The thermal runaway smoke includes combustibles such as electrolyte, hydrogen, carbon monoxide, methane, and ethylene, and combustibles account for a large proportion of the thermal runaway smoke. When the thermal runaway smoke is discharged from the battery shell, the combustibles come into contact with the air and are prone to combustion. In severe cases, they can cause explosions, posing safety hazards. Summary of the invention

[0004] In order to solve the potential safety hazard problem of thermal runaway smoke being discharged outside the battery housing, the utility model provides a thermal runaway smoke treatment device.

[0005] In order to achieve the above object, the technical solution of the utility model is:

[0006] A thermal runaway flue gas treatment device comprises a liquid treatment device and a gas generating device; the liquid treatment device comprises at least one liquid treatment tank, the liquid treatment tank is provided with a flue gas inlet and a flue gas outlet connected to its inner cavity, and the liquid treatment tank is filled with a liquid treatment medium, the liquid treatment medium is mainly used to treat the electrolyte in the thermal runaway flue gas; the gas generating device is used to generate a flame retardant gas, and the flame retardant gas and the thermal runaway flue gas treated by the liquid treatment device are mixed and discharged.

[0007] Furthermore, the liquid treatment medium is an alkaline solution.

[0008] Furthermore, the alkaline solution is a 0.05-0.5 mol / L NaOH solution.

[0009] Furthermore, a three-way valve is provided on the smoke outlet of the liquid treatment tank, a first port of the three-way valve is connected to the inner cavity of the liquid treatment tank, a third port is used to inject liquid treatment medium, and a second port is used to discharge thermal runaway smoke.

[0010] Furthermore, the smoke inlet and the smoke outlet are both arranged at the top of the liquid treatment tank, the smoke inlet is connected to a smoke inlet pipe, at least a portion of the smoke inlet pipe can be immersed in the liquid treatment medium, and a diversion part is provided at the end of the smoke inlet pipe immersed in the liquid treatment medium.

[0011] Furthermore, a spiral baffle is provided on the smoke inlet pipeline or a plurality of baffles are provided on the smoke inlet pipeline to increase the distance traveled by the thermal runaway flue gas in the liquid treatment tank.

[0012] Furthermore, the gas generating device includes at least one gas generating tank; the gas generating tank includes a first tank body, a second tank body and a flue gas pipeline; the first tank body is provided with a gas outlet connected to its inner cavity; the second tank body is arranged in the first tank body, and the second tank body is provided with an opening, and an isolation piece is installed on the opening; the inlet of the flue gas pipeline extends to the outside of the first tank body and is provided with a one-way valve, and the outlet of the flue gas pipeline is connected to the inner cavity of the second tank body for conveying the thermal runaway flue gas into the second tank body; the first tank body contains a first reaction medium, and the second tank body contains a second reaction medium, and the isolation piece is opened after the pressure in the second tank body reaches a set value, and the first reaction medium and the second reaction medium contact and react to generate flame-retardant gas, and the flame-retardant gas and the thermal runaway flue gas are mixed and discharged through the gas outlet on the first tank body.

[0013] Furthermore, a mixing structure is provided in the first tank body, and the mixing structure is a plurality of baffles fixed on the inner wall of the first tank body, and a filter is provided below the mixing structure.

[0014] Furthermore, the flame retardant gas is carbon dioxide, the first reaction medium is water, and the second reaction medium is sodium bicarbonate and aluminum sulfate solid.

[0015] Furthermore, the second tank body is a cylindrical structure with an open bottom, and its open end is fixed to the bottom plate of the first tank body. The gas outlet is arranged on the top of the first tank body, and the isolation member is arranged on the top of the second tank body, and the isolation member is an isolation membrane.

[0016] Compared with the prior art, the technical solution of the utility model has the following advantages:

[0017] 1. The thermal runaway flue gas treatment device of the utility model comprises a liquid treatment device and a gas generating device. The liquid treatment device is mainly used to treat the electrolyte in the thermal runaway flue gas to prevent the vaporized electrolyte from continuing to decompose and produce combustible gas, thereby reducing the amount of combustible gas. Subsequently, the gas generating device generates a flame retardant gas, and mixes the flame retardant gas with the thermal runaway flue gas treated by the liquid treatment device and discharges the mixture. The proportion of combustible gas in the discharged mixed gas is greatly reduced, and it is difficult to burn or explode after contacting with the air, thereby solving the potential safety hazard problem of thermal runaway flue gas being discharged outside the battery casing.

[0018] 2. In the thermal runaway flue gas treatment device of the utility model, the liquid treatment medium is an alkaline solution, which can not only fully treat the electrolyte carried in the thermal runaway flue gas to prevent the vaporized electrolyte from continuing to decompose and produce combustible gas, but also treat part of the gas in the thermal runaway flue gas. The gas volume of the thermal runaway flue gas treated with the alkaline solution is greatly reduced. Among them, the treatment effect of 0.05-0.5 mol / L NaOH solution on thermal runaway flue gas is more prominent.

[0019] 3. In the thermal runaway flue gas treatment device of the utility model, a three-way valve is provided on the flue gas outlet of the liquid treatment tank. The three-way valve can be used to fill the liquid treatment medium after the air tightness test of the liquid treatment tank is completed. There is no need to conduct a secondary air tightness test on the liquid treatment tank, thereby improving the assembly efficiency of the liquid treatment device.

[0020] 4. In the thermal runaway flue gas treatment device of the utility model, the flue gas inlet and the flue gas outlet on the liquid treatment tank are both arranged at the top of the liquid treatment tank, which improves the connectivity of the entire device and the compactness of the pipeline layout. At the same time, a smoke inlet pipeline is arranged in the liquid treatment tank, and at least part of the smoke inlet pipeline can be immersed in the liquid treatment medium, so that the thermal runaway flue gas can fully contact with the liquid treatment medium. At the same time, a diversion part is arranged at one end of the smoke inlet pipeline immersed in the liquid treatment medium. When the thermal runaway flue gas passes through the liquid treatment tank, the diversion part breaks up and diverts the thermal runaway flue gas and then reacts with the liquid treatment medium in the liquid treatment tank, so that the thermal runaway flue gas and the liquid treatment medium are more fully contacted and reacted, which improves the treatment effect of the liquid treatment medium and the treatment of the thermal runaway flue gas is more thorough.

[0021] 5. In the thermal runaway flue gas treatment device of the utility model, a spiral baffle or multiple baffles are arranged on the smoke inlet pipe. When the thermal runaway flue gas passes through the liquid treatment tank, the spiral baffle or multiple baffles increase the stroke of the thermal runaway flue gas, so that the thermal runaway flue gas can more fully contact and react with the liquid treatment medium, further improving the treatment effect of the liquid treatment medium.

[0022] 6. In the thermal runaway flue gas treatment device of the utility model, the thermal runaway flue gas treated by the liquid treatment device passes through the inner cavity of the second tank body, the isolation piece on the second tank body is opened, and the first reaction medium in the first tank body contacts and reacts with the second reaction medium in the second tank body to generate flame-retardant gas. This gas generating device can generate flame-retardant gas in time when the thermal runaway flue gas passes through, and can fully mix the flame-retardant gas and the thermal runaway flue gas and then discharge them. At the same time, a one-way valve is provided at the inlet of the flue gas pipeline. The one-way valve can hold back the thermal runaway flue gas in the second tank body so that the thermal runaway flue gas can smoothly open the isolation piece on the second tank body. At the same time, the one-way valve can also prevent the thermal runaway flue gas from flowing back into the liquid treatment device and affecting the liquid treatment medium in the liquid treatment device.

[0023] 7. In the thermal runaway flue gas treatment device of the utility model, a mixing structure is provided inside the first tank body. The mixing structure is a plurality of baffles fixed on the inner wall of the first tank body. The baffles increase the distance for the flame-retardant gas and the thermal runaway flue gas to pass through, further uniformly mix the flame-retardant gas and the thermal runaway flue gas, and reduce the probability of combustion still occurring due to excessive local concentration of combustible gas in the mixed gas. At the same time, a filter is provided below the mixing structure, which filters impurities such as solid matter in the flame-retardant gas and the thermal runaway flue gas to avoid clogging the gas outlet on the first tank body.

[0024] 8. In the thermal runaway flue gas treatment device of the utility model, the flame retardant gas is carbon dioxide which is easy to make and has good flame retardant effect. At the same time, the carbon dioxide is obtained by reacting water, sodium bicarbonate and aluminum sulfate solids which are easy to fill.

[0025] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic structural diagram of a thermal runaway flue gas treatment device in an embodiment;

[0028] Figure 2 This is a schematic diagram of an explosion of a liquid treatment tank in an embodiment;

[0029] Figure 3 is a cross-sectional view of a liquid treatment tank in an embodiment;

[0030] Figure 4 A cross-sectional view of a liquid treatment tank (including a spiral baffle) in an embodiment;

[0031] Figure 5 It is a cross-sectional view of the liquid treatment tank (including the baffle) in the embodiment;

[0032] Figure 6 is a cross-sectional view of a gas generating tank in an embodiment;

[0033] Figure 7 It is a cross-sectional view of the gas generating tank (including the mixing structure) in the embodiment.

[0034] Figure markings: 1-liquid treatment device, 2-gas generating tank, 11-liquid treatment tank, 12-three-way valve, 13-smoke inlet, 14-smoke outlet, 15-smoke inlet pipeline, 16-diversion part, 17-spiral baffle, 18-baffle, 19-connecting pipeline, 121-first port, 122-second port, 123-third port, 21-first tank body, 22-second tank body, 23-smoke pipeline, 24-mixing structure, 25-one-way valve, 26-filter, 211-gas outlet, 221-opening, 222-isolating member. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary persons in the field without creative work should fall within the scope of protection of the utility model.

[0036] The "other embodiments" that appear in different places in this specification do not all refer to the same embodiment, nor are they separate or selective embodiments that are mutually exclusive with other embodiments. In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of this utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited.

[0037] In the description of this specification, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate, or the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0038] At the same time, in the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "top, bottom, inside and outside" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] Research shows that when a lithium-ion battery experiences thermal runaway, a series of chemical reactions will occur inside, releasing a large amount of heat and gas, such as: SEI film decomposition reaction (90-120°C), cathode and electrolyte reaction (100-350°C), electrolyte decomposition reaction (110-300°C), diaphragm shrinkage and melting reaction (>130°C), cathode and electrolyte reaction (200-300°C), and binder decomposition reaction (200-300°C), etc. The above reactions do not occur in a fixed order, nor do they proceed independently.

[0040] When the battery temperature is around 90-120℃, first, the SEI film decomposes, releasing heat and producing gases such as C2H4, CO2 and O2. As the temperature continues to rise, when the battery temperature is around 120℃, the negative electrode surface has lost the protection of the SE I film, and the embedded lithium reacts with the electrolyte organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) to produce C x H y Gas. When the temperature is 110-300°C, the electrolyte and the electrolyte itself will also undergo a series of decomposition reactions to produce some fluorides. As the temperature continues to rise, the positive electrode material begins to decompose and produce O2. The O2 produced by the decomposition of the positive electrode material reacts with the solvent of the electrolyte: when the O2 concentration is high, the reaction produces CO2, and when the O2 concentration is low, the reaction produces CO. When the battery temperature exceeds 235°C, the binder polyvinylidene fluoride (PVDF) will react with lithium and self-decompose.

[0041] From the above process, it can be seen that when the battery is in thermal runaway, the exhaust gas mainly includes the following components: vaporized electrolyte, CO2, CO, H2, C x H y , C x H y O z , C x H yF, POF3 and HF, etc. The thermal runaway flue gas contains not only hydrogen, CO, CO2, methane and other gases, but also a large amount of electrolyte vapor. The vaporized electrolyte will not only react with the positive or negative electrode in the battery cavity, but also undergo a series of decomposition reactions, thereby continuing to produce a large amount of harmful gases and flammable gases.

[0042] The utility model provides a thermal runaway flue gas treatment device, in which a liquid treatment device first treats the electrolyte in the thermal runaway flue gas to prevent the vaporized electrolyte from continuing to undergo a decomposition reaction to produce combustible gas, thereby reducing the amount of combustible gas; subsequently, a gas generating device generates a flame retardant gas, and the flame retardant gas and the thermal runaway flue gas treated by the liquid treatment device are mixed and discharged; the proportion of combustible gas in the discharged mixed gas is greatly reduced, and it is difficult to burn or explode after contacting with air, thereby solving the potential safety hazard problem of thermal runaway flue gas being discharged outside the battery casing.

[0043] like Figure 1 As shown, the thermal runaway flue gas treatment device in this embodiment includes a liquid treatment device 1 and a gas generating device; the liquid treatment device 1 includes at least one liquid treatment tank 11, which is filled with a liquid treatment medium and is mainly used to treat the electrolyte in the thermal runaway flue gas; the gas generating device is used to generate a flame retardant gas, and mix the flame retardant gas with the thermal runaway flue gas treated by the liquid treatment device 1 and then discharge it, thereby reducing the concentration of combustible gas in the thermal runaway flue gas. The structures of the liquid treatment device 1 and the gas generating device are described in detail below.

[0044] In the above liquid treatment device 1, the number of liquid treatment tanks 11 can be set according to the number and demand of lithium-ion batteries. If there are multiple liquid treatment tanks 11, multiple liquid treatment tanks 11 can be connected in series through the connecting pipe 19. The shape of the liquid treatment tank 11 is not limited, and can be a rectangular tank body, a circular tank body, an elliptical tank body, etc., and a circular tank body is preferably used, which has good pressure-bearing performance.

[0045] like Figure 2As shown, the liquid treatment tank 11 is provided with a smoke inlet 13 and a smoke outlet 14. The smoke inlet 13 is used to input the thermal runaway smoke into the liquid treatment tank 11, and the smoke outlet 14 is used to discharge the treated thermal runaway smoke. When the smoke inlet 13 is specifically set, it can be set at the top of the liquid treatment tank 11, or it can be set at the bottom of the liquid treatment tank 11. In order to facilitate the connection of each liquid treatment tank 11, it is preferred to set the smoke inlet 13 and the smoke outlet 14 at the top of the liquid treatment tank 11. At this time, each liquid treatment tank 11 only needs to be connected at the top, which improves the connectivity of the entire thermal runaway smoke treatment device and the compactness of the pipeline layout. In addition, the above-mentioned connecting pipeline 19 can adopt a metal bellows. After the metal corrugated connection is adopted, each liquid treatment tank 11 can be arranged according to the requirements of the installation space, meet various installation requirements, and save installation space.

[0046] Before using the above-mentioned liquid treatment tank 11, it is generally necessary to carry out a corresponding airtight pressure leak test to ensure the sealing and reliability of the liquid treatment tank 11 during subsequent use. When the liquid treatment tank 11 is subjected to a pressure leak test, the first pressure leak test is generally carried out on an empty liquid treatment tank 11. After the first pressure leak test is completed, the liquid treatment tank 11 is filled with a liquid treatment medium, and then multiple liquid treatment tanks 11 are connected through a connecting pipe 19. After connecting multiple liquid treatment tanks 11, it is necessary to carry out a second pressure leak test on the connecting pipes 19 between the liquid treatment tanks 11. The two pressure leak tests result in a lower detection efficiency of the liquid treatment tank 11, which further reduces the assembly efficiency of the liquid treatment device.

[0047] like Figure 2 and Figure 3 As shown, in order to facilitate the injection of liquid treatment medium and the pressure test of the liquid treatment tank 11 for leak detection, a three-way valve 12 is provided on the above-mentioned smoke outlet 14. The three-way valve 12 can be a three-way ball valve or the like. The three-way valve 12 can be used to fill the liquid treatment medium after the pressure test of all liquid treatment tanks 11 is completed. When specifically connected, the first port 121 of the three-way valve 12 is connected to the smoke outlet 14, the second port 122 is used to discharge the thermal runaway smoke, and the third port 123 is used to inject the liquid treatment medium.

[0048] like Figure 3As shown, after the smoke inlet 13 is set at the top of the liquid treatment tank 11, in order to make the thermal runaway smoke fully contact with the liquid treatment medium in the liquid treatment tank 11, the smoke inlet 13 is connected with a smoke inlet pipe 15, and at least part of the smoke inlet pipe 15 can be immersed in the liquid treatment medium. Optimally, the smoke inlet pipe 15 preferably extends to the bottom of the liquid treatment tank 11 and can be completely immersed in the liquid treatment medium. When the thermal runaway smoke passes through the liquid treatment tank 11, it fully contacts the liquid treatment medium in the liquid treatment tank 11, and the liquid treatment medium performs a relatively sufficient treatment on the thermal runaway smoke, thereby improving the treatment effect of the liquid treatment medium.

[0049] like Figure 3 As shown, a diversion portion 16 may also be provided at one end of the smoke inlet pipe 15 immersed in the liquid treatment medium. The diversion portion 16 disperses and diverts the thermal runaway flue gas before reacting with the liquid treatment medium in the liquid treatment tank 11, so that the thermal runaway flue gas enters in a large flow and exits in a small flow, which is beneficial to the dispersion of the thermal runaway flue gas, so that the thermal runaway flue gas and the liquid treatment medium are fully contacted and reacted, thereby improving the treatment effect of the liquid treatment medium. In the present embodiment, the diversion portion 16 is a foam copper column, which is easy to install and has a better dispersion and diversion effect. When the foam copper column is specifically installed, it is fixed to the port at one end of the smoke inlet pipe 15 immersed in the liquid treatment medium. Foam copper is a structure with a large number of three-dimensional holes in a copper matrix, which has a dispersing and buffering effect on the fluid. When in use, it is processed into a columnar structure, and the thermal runaway flue gas flows out from the foam copper column through the smoke inlet pipe 15, and then flows out through the side wall or bottom of the foam copper column to achieve the dispersion and buffering effect on the thermal runaway flue gas, so that the thermal runaway flue gas after diversion is fully in contact with the liquid treatment medium.

[0050] like Figure 4 and Figure 5 As shown, in order to further allow the thermal runaway flue gas to fully react with the liquid treatment medium, a spiral baffle 17 is provided on the above-mentioned smoke inlet pipe 15, or a plurality of baffles 18 are provided on the smoke inlet pipe 15. The spiral baffle 17 or a plurality of baffles 18 increase the travel of the thermal runaway flue gas when the thermal runaway flue gas passes through the liquid treatment tank 11, so that the thermal runaway flue gas can more fully contact with the liquid treatment medium. The thermal runaway flue gas enters from the flue gas inlet 13 of the liquid treatment tank 11, and then enters the bottom of the liquid treatment medium through the smoke inlet pipe 15, and then is broken up by the foam copper column. Then, during the process of rising from the bottom, the spiral baffle 17 or a plurality of baffles 18 will allow the thermal runaway flue gas to fully contact with the liquid treatment medium in the liquid treatment tank 11, so as to perform corresponding treatment. During the specific connection, the spiral baffle 17 can be fixed on the smoke inlet pipe 15. The baffles 18 are semicircular baffles, and a plurality of baffles 18 are arranged in sequence from bottom to top and are respectively fixed on the smoke inlet pipe 15 , and adjacent baffles 18 are installed in a staggered manner.

[0051] The liquid treatment tank 11 is filled with a liquid treatment medium, which is mainly used to fully treat the electrolyte carried in the thermal runaway flue gas to prevent the vaporized electrolyte from continuing to decompose and produce combustible gas, thereby reducing the content of combustibles (electrolyte and combustible gas) in the thermal runaway flue gas. The liquid treatment medium can specifically use the following substances:

[0052] First, the liquid treatment medium can be an organic solvent. According to the principle of like dissolves like, the organic solvent can fully treat the electrolyte carried in the thermal runaway flue gas, and at the same time can prevent the vaporized electrolyte from continuing to decompose. The organic solvent is specifically an ester solvent, an alcohol solvent or an aldehyde solvent. The ester solvent can specifically be diethyl phthalate solvent, methyl salicylate solvent, ethyl acetate solvent or butyl acetate solvent, etc. The alcohol solvent can specifically be benzyl alcohol solvent, isopentanol solvent, isobutanol solvent, isopropanol solvent, isooctyl alcohol solvent, n-propanol solvent or cyclohexanol solvent, etc. The aldehyde solvent is benzaldehyde solvent, heptaldehyde, phenylpropionaldehyde or methylnonaneacetaldehyde, etc.

[0053] Second, the liquid treatment medium is an alkaline solution, which can specifically be an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous barium hydroxide solution, etc. The alkaline solution can react with carbonate substances in the electrolyte to prevent the vaporized electrolyte from continuing to produce harmful gases and combustible gases, and treat the thermal runaway flue gas to a certain extent at the source. At the same time, the alkaline solution has a good treatment effect on acidic substances such as CO2, POF3 and HF, and can effectively treat some gases in the thermal runaway flue gas. In addition, the alkaline solution can cool the thermal runaway flue gas and fully dissolve the electrolyte vapor in the thermal runaway flue gas in the alkaline solution.

[0054] Among the above two liquid treatment media, the alkaline solution can not only treat the electrolyte in the thermal runaway flue gas, but also treat the gas in the thermal runaway flue gas. Therefore, the alkaline solution has a better treatment effect than the organic solvent.

[0055] For alkaline solutions, generally, the higher the concentration, the better the treatment effect on thermal runaway flue gas. However, the applicant found that low-concentration alkaline solutions have better treatment effects than high-concentration alkaline solutions, especially 0.05-0.5 mol / L alkaline solutions. When thermal runaway flue gas passes through an alkaline solution of this concentration, the amount of gas collected is minimal, and its treatment effect is better than that of alkaline solutions with a concentration of more than 0.5 mol / L. Therefore, the prejudice of the prior art is overcome, and a low-concentration alkaline solution is used to treat thermal runaway flue gas, so that the alkaline solution can achieve more effective treatment of thermal runaway flue gas.

[0056] Taking the alkaline solution as NaOH solution as an example, a large number of battery thermal runaway tests were carried out. After a horizontal comparison of the treatment effects of water and NaOH solutions of different concentrations on thermal runaway flue gas, it was found that the volume of gas collected after the thermal runaway flue gas was the smallest after being treated with 0.05-0.5 mol / L NaOH solution, the effect was significant after being treated with 0.1-0.2 mol / L NaOH solution, and the best effect was achieved after being treated with 0.1 mol / L NaOH solution.

[0057] Table 1 Unprocessed full-charge 32650 battery out-of-control data

[0058]

[0059] Table 2 Treatment results of different concentrations of NaOH solution

[0060]

[0061]

[0062] When the thermal runaway flue gas is transported to the NaOH solution, the NaOH solution reacts with the electrolyte, CO2, POF3 and acidic substances such as HF in the thermal runaway flue gas. For example, the ester in the electrolyte reacts with the NaOH solution: CHOOCR+NaOH=RCOONa+CHOH; CO2 reacts with the NaOH solution: 2NaOH+CO2=Na2CO3+H2O; CO2 will also react subsequently: Na2CO3+CO2+H2O=2NaHCO3; POF3 reacts with the NaOH solution: POF3+2NaOH=NaPF2O2+NaF+H2O; HF reacts with the NaOH solution: NaOH+HF=NaF+H2O. After the above reactions, the volume of the thermal runaway flue gas is greatly reduced.

[0063] According to the above test data, when the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway is not treated in any way, the collected gas volume is 4L. When the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway passes through a NaOH solution with a concentration of 0.5mol / L or more, the collected gas is generally greater than 2L, and the treatment effect is not ideal. After the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway passes through a 0.05-0.5mol / L NaOH solution, the gas volume is small, all below 2L. After being treated with 0.1-0.2mol / L sodium hydroxide, the effect is significant. After being treated with 0.1mol / L sodium hydroxide, the collected gas volume is the smallest, only about 1L, and the effect is the best. Therefore, 0.05-0.5mol / L NaOH solution has a good treatment effect on the thermal runaway flue gas after battery thermal runaway.

[0064] In the above-mentioned liquid treatment device, the liquid treatment medium can effectively treat the thermal runaway flue gas, so that the volume of the treated thermal runaway flue gas is greatly reduced. On this basis, a gas generating device is connected to the rear end of the liquid treatment device 1, and the gas generating device generates a flame-retardant gas, and mixes the flame-retardant gas with the thermal runaway flue gas treated by the liquid treatment device 1, thereby reducing the concentration of combustible gas in the thermal runaway flue gas. Since the concentration of the combustible gas in the mixed gas is relatively small, it is difficult to cause safety hazards such as combustion or explosion when it comes into contact with air.

[0065] like Figure 1 and Figure 6 As shown, the gas generating device in this embodiment includes at least one gas generating tank 2, and the gas generating tank 2 includes a first tank body 21, a second tank body 22 and a flue gas pipeline 23; the first tank body 21 is provided with a gas outlet 211 connected to its inner cavity; the second tank body 22 is arranged in the first tank body 21, and the second tank body 22 is provided with an opening 221, and an isolation member 222 is installed on the opening 221, and the isolation member 222 is used to isolate the inner cavities of the first tank body 21 and the second tank body 22; the flue gas pipeline 23 is mainly used to transport the thermal runaway flue gas treated by the liquid treatment device 1 to the second tank body 22. When the flue gas pipeline 23 is installed, the inlet extends to the outside of the first tank body 21 and is connected to the smoke outlet 14 of the last liquid treatment tank 11 in the liquid treatment device 1, and the outlet is connected to the inner cavity of the second tank body 22. When the smoke pipe 23 is installed, a through hole is set on the top of the second tank body 22. The smoke pipe 23 passes through the through hole and is connected to the smoke outlet 14 of the liquid treatment tank 11, and its inlet is connected to the second tank body 22.

[0066] The first tank body 21 contains a first reaction medium, and the second tank body 22 contains a second reaction medium. The isolation piece 222 is opened after the pressure in the second tank body 22 reaches a set value, and the first reaction medium and the second reaction medium come into contact and react to produce a flame-retardant gas. The flame-retardant gas and the thermal runaway flue gas are mixed and discharged through the gas outlet 211 on the first tank body 21. The proportion of combustible gas in the discharged mixed gas is greatly reduced, and it is difficult to burn or explode after contacting with air.

[0067] like Figure 6As shown, the present embodiment does not limit the shape of the first tank body 21, which may be a rectangular tank body, a circular tank body, an elliptical tank body, and the like. Preferably, the first tank body 21 adopts a circular tank body, which has good pressure-bearing performance. The above-mentioned first tank body 21 is provided with a gas outlet 211 connected to its inner cavity, and the gas outlet 211 mainly discharges the mixed gas in the first tank body 21. The specific position of the gas outlet 211 is not required, as long as the mixed gas can be discharged. In this embodiment, in order to ensure the smooth discharge of the mixed gas, the gas outlet 211 is arranged at the top of the first tank body 21. At the same time, a pipeline can also be installed on the gas outlet 211 to transport the mixed gas to a designated point through the pipeline for directional and safe discharge.

[0068] like Figure 6 As shown, the second tank body 22 is placed in the first tank body 21 as a whole. Similarly, the shape of the second tank body 22 is not limited, and can be a rectangular tank body, a circular tank body, an elliptical tank body, etc. Similar to the first tank body 21, the second tank body 22 is also a cylindrical tank body. At the same time, in order to facilitate manufacturing and installation, the second tank body 22 adopts a cylindrical structure with an open bottom. When installed, the bottom open end is fixedly installed on the bottom of the first tank body 21, and the bottom open end is sealed by the bottom plate of the first tank body 21.

[0069] The second tank body 22 has an opening 221 connected to its inner cavity, and an isolating member 222 is provided on the opening 221. The isolating member 222 can be a separation membrane or a pressure valve. The opening pressure of the separation membrane or the pressure valve is relatively small, for example, the opening pressure is less than 0.1 MPa, and can be opened in time when the thermal runaway flue gas passes through. The separation membrane and the pressure valve are opened when the pressure of the thermal runaway flue gas in the second tank body 22 reaches a certain value. At this time, the inner cavity of the first tank body 21 and the inner cavity of the second tank body 22 are connected through the opening 221, so that the first reaction medium in the first tank body 21 and the second reaction medium in the second tank body 22 contact through the opening 221 to react. When the above-mentioned isolation member 222 is installed, it can be set at any position of the second tank body 22, preferably at the top of the second tank body 22. At this time, the thermal runaway smoke and flame-retardant gas in the second tank body 22 can flow out of the second tank body 22 very smoothly. If the isolation member 222 is set on the side wall or bottom of the second tank body 22, the thermal runaway smoke and flame-retardant gas may not be discharged smoothly.

[0070] like Figure 6 As shown, a one-way valve 25 can also be provided at the inlet of the above-mentioned flue gas pipeline 23. The one-way valve 25 can hold back the pressure of the thermal runaway flue gas in the second tank body 22 so that the thermal runaway flue gas can smoothly open the isolation piece 222 on the second tank body 22. At the same time, the one-way valve 25 prevents the thermal runaway flue gas from flowing back into the liquid treatment device and affecting the liquid treatment medium in the liquid treatment device.

[0071] After being treated by the liquid treatment medium in the liquid treatment tank 11, the thermal runaway flue gas enters the second tank body 22, and the thermal runaway flue gas gathers in the second tank body 22 until the pressure in the second tank body 22 reaches a certain value, and the isolation piece 222 is opened, and the first reaction medium and the second reaction medium contact and react to produce a flame retardant gas. The flame retardant gas is specifically a non-flammable gas, which is used to dilute the thermal runaway flue gas and reduce the concentration of the combustible gas when the thermal runaway flue gas is discharged, so that the content of the combustible gas in the thermal runaway flue gas is lower than its lower explosion limit, and finally achieves a non-flammable effect. The above-mentioned flame retardant gas may specifically include inert gases, carbon dioxide gas and other non-combustible gases. The flame retardant gas is preferably carbon dioxide gas, which can be obtained through a reaction under relatively simple conditions and also has a certain fire extinguishing effect.

[0072] At room temperature, carbon dioxide gas can be obtained by reacting different liquid or solid substances. There are different placement methods according to the reaction principle:

[0073] 1) The first reaction medium is water, and the second reaction medium is sodium bicarbonate and aluminum sulfate solid;

[0074] 2) The first reaction medium is an aluminum sulfate solution, and the second reaction medium is a sodium bicarbonate solution;

[0075] 3) The first reaction medium is a sodium bicarbonate solution, and the second reaction medium is an aluminum sulfate solid;

[0076] 4) The first reaction medium is solid sodium bicarbonate, and the second reaction medium is aluminum sulfate solution;

[0077] In the above method, the first reaction medium is water, and the second reaction medium is sodium bicarbonate and aluminum sulfate solid, which is the best choice. This method is convenient for filling separately and can continue to maintain its effect after being placed for a long time.

[0078] When the first reaction medium and the second reaction medium are filled, if the second reaction medium is a solid substance, it can be built into the second tank body 22 in advance, and then the second tank body 22 is fixed in the first tank body 21, or the second reaction medium can be filled through the flue gas pipeline 23. If the second reaction medium is a liquid substance, the second tank body 22 is placed in the first tank body 21, and then the second reaction medium is filled through the flue gas pipeline 23. If the first reaction medium can be added through the gas outlet 211 after the second tank body 22 and the flue gas pipeline 23 are installed.

[0079] When the first reaction medium and the second reaction medium react, some solid impurities may be generated, or the thermal runaway flue gas may carry solid substances generated by the thermal runaway of the battery. The above solid impurities will be discharged with the mixed gas and block the gas outlet 211 on the first tank body 21 or the subsequent pipeline. Figure 7 As shown, a filter screen 26 is added to the top of the inner cavity of the first tank body 21, and the filter screen 26 removes the above impurities to ensure that the mixed gas can be discharged smoothly.

[0080] like Figure 7 As shown, in order to fully mix the flame retardant gas generated by the first reaction medium and the second reaction medium with the thermal runaway flue gas, the present embodiment may further provide a mixing structure 24 in the first tank body 21, the mixing structure 24 enables the flame retardant gas and the thermal runaway flue gas to be evenly mixed, and the mixing structure 24 includes a plurality of baffles, which are arranged in sequence from bottom to top, respectively fixed on the inner wall of the first tank body 21, and adjacent baffles are installed in a staggered manner. When the thermal runaway flue gas passes through the gas generating tank 2, the above-mentioned baffles can, on the one hand, extend the mixing path of the flame retardant gas and the thermal runaway flue gas, increase the mixing time of the flame retardant gas and the thermal runaway flue gas, thereby improving the mixing effect of the two; on the other hand, it further intensifies the mutual collision and mixing of the flame retardant gas and the thermal runaway flue gas, thereby improving the mixing effect of the two, and reducing the probability of combustion still occurring due to excessive local concentration of combustible gas in the mixed gas.

[0081] In other embodiments, the gas generating device may also be an existing aerosol smoke generating device or an inert gas generating device.

[0082] The gas generating device in this embodiment includes at least one of the above-mentioned gas generating tanks 2, and the number of gas generating tanks 2 is set accordingly according to the number of lithium-ion batteries. If there are multiple gas generating tanks 2, the multiple gas generating tanks 2 can be set in series or in parallel. If they are set in series, the thermal runaway flue gas is diluted in sequence until the content of combustible gas in the thermal runaway flue gas discharged from the last gas generating tank 2 is lower than its lower explosion limit. If multiple gas generating tanks 2 are set in parallel, the thermal runaway flue gas treated by the liquid treatment device 1 is divided into multiple portions, and each gas generating tank 2 dilutes each portion of thermal runaway flue gas, and the content of combustible gas in the mixed gas discharged from each gas generating tank 2 is lower than its lower explosion limit. In addition, multiple gas generating tanks 2 can also be combined in series and parallel, as long as the content of combustible gas in the discharged mixed gas is lower than its lower explosion limit.

Claims

1. A thermal runaway flue gas treatment device, characterized in that: including a liquid handling device and a gas generating device; The liquid treatment device comprises at least one liquid treatment tank, the liquid treatment tank is provided with a smoke inlet and a smoke outlet communicated with its inner cavity, and the liquid treatment tank is filled with a liquid treatment medium, the liquid treatment medium is mainly used to treat the electrolyte in the thermal runaway smoke; The gas generating device is used to generate flame retardant gas, and mix the flame retardant gas with the thermal runaway smoke treated by the liquid treating device and then discharge the mixture.

2. The thermal runaway flue gas treatment device according to claim 1, characterized in that: The liquid treatment medium is an alkaline solution.

3. The thermal runaway flue gas treatment device according to claim 2, characterized in that: The alkaline solution is a 0.05-0.5 mol / L NaOH solution.

4. The thermal runaway flue gas treatment device according to claim 1, characterized in that: A three-way valve is provided on the smoke outlet of the liquid treatment tank, the first port of the three-way valve is connected to the inner cavity of the liquid treatment tank, the third port is used to inject liquid treatment medium, and the second port is used to discharge thermal runaway smoke.

5. The thermal runaway flue gas treatment device according to claim 4, characterized in that: The smoke inlet and the smoke outlet are both arranged at the top of the liquid treatment tank. The smoke inlet is connected to a smoke inlet pipeline. At least a part of the smoke inlet pipeline can be immersed in the liquid treatment medium, and a diversion part is arranged at the end of the smoke inlet pipeline immersed in the liquid treatment medium.

6. The thermal runaway flue gas treatment device according to claim 5, characterized in that: The smoke inlet pipeline is provided with a spiral baffle or a plurality of baffles are provided on the smoke inlet pipeline to increase the travel distance of the thermal runaway flue gas in the liquid treatment tank.

7. The thermal runaway flue gas treatment device according to any one of claims 1 to 6, characterized in that: The gas generating device comprises at least one gas generating tank; the gas generating tank comprises a first tank body, a second tank body and a flue gas pipeline; the first tank body is provided with a gas outlet connected to its inner cavity; the second tank body is arranged in the first tank body, and the second tank body is provided with an opening, and an isolation piece is installed on the opening; the inlet of the flue gas pipeline extends to the outside of the first tank body and is provided with a one-way valve, and the outlet of the flue gas pipeline is connected to the inner cavity of the second tank body for conveying the thermal runaway flue gas into the second tank body; the first tank body contains a first reaction medium, and the second tank body contains a second reaction medium, and the isolation piece is opened after the pressure in the second tank body reaches a set value, and the first reaction medium and the second reaction medium contact and react to generate flame-retardant gas, and the flame-retardant gas and the thermal runaway flue gas are mixed and discharged through the gas outlet on the first tank body.

8. The thermal runaway flue gas treatment device according to claim 7, characterized in that: A mixing structure is disposed in the first tank body, wherein the mixing structure is a plurality of baffles fixed on the inner wall of the first tank body, and a filter is disposed below the mixing structure.

9. The thermal runaway flue gas treatment device according to claim 7, characterized in that: The flame retardant gas is carbon dioxide, the first reaction medium is water, and the second reaction medium is sodium bicarbonate and aluminum sulfate solid.

10. The thermal runaway flue gas treatment device according to claim 7, characterized in that: The second tank body is a cylindrical structure with an open bottom, and its open end is fixed to the bottom plate of the first tank body. The gas outlet is arranged on the top of the first tank body, and the isolation member is arranged on the top of the second tank body, and the isolation member is an isolation membrane.

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