Acid-scavenging and fire-suppressing device and method for lithium-ion batteries

Abstract

A fire-mitigation device for lithium-ion battery fires includes a low-permeability layer; a semi-permeable membrane; and an acid-scavenging medium layer disposed between the low-permeability anti-fragmentation layer and the semi-permeable membrane, and wherein at least one of the low-permeability layer or the acid-scavenging medium layer is an anti-fragmentation layer.

Description

[0001] ACID-SCAVENGING AND FIRE-SUPPRESSING DEVICE AND METHOD FOR LITHIUM-ION BATTERIES

[0002] Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 751,351 (filed January 30, 2025), which is hereby incorporated herein by reference in its entirety.

[0004] Federally-Sponsored Research and Development This invention was made with United States Government support from the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce. The Government has certain rights in this invention.

[0005] Copyright Notice

[0006] This patent disclosure may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves any and all copyright rights.

[0007] Field of Invention

[0008] The present invention relates generally to fire suppression, and more particularly to acid-scavenging and fire-suppressing technologies for lithium-ion batteries.

[0009] Background

[0010] Unlike conventional fires, thermal runaway in Li-ion batteries introduces unique dangers due to the creation of vapor clouds and battery fragmentation. There are two types of vapor clouds: buoyant and heavy clouds. Buoyant clouds primarily consist of hydrogen, carbon monoxide, and carbon dioxide, while heavy clouds, which settle down and persist longer, are extremely toxic and reactivedue to the presence of heavy metals, hydrogen fluoride (HF), hydrogen chloride (HCI), hydrogen cyanide (HCN), and organic solvents. In indoor fires, these acidic gases can lead to poisoning, lung damage, and increased fire losses by damaging electronic components and escalating restoration costs.

[0011] Summary of Invention

[0012] Although there are various suppression methods for lithium-ion battery fires, none is fully effective and addresses the issue of acidic gas emissions. Fire blankets are often used to limit flame spread (by reducing convective and radiative heat transfer to the surrounding items) and oxygen supply to smother the flame, however smothering is rarely successful in Li-ion battery fires since thermal runaway generates additional oxygen. Conventional fire blankets are made from costly specialty fabrics, such as aluminum-zirconium-silicate, oxidized polyacrylonitrile, aramids, and alkali-free high-silica glass, coated with silicone or polyurethane. While these fabrics are excellent thermal insulators and can isolate the fire, this can paradoxically increase battery temperature by restricting air cooling, enhance gas production and elevate the risk of explosion.

[0013] According to one aspect of the invention, a fire-mitigation device for lithium-ion battery fires includes a low-permeability layer; a semi-permeable membrane; and an acid-scavenging medium layer disposed between the low-permeability anti-fragmentation layer and the semi-permeable membrane, wherein at least one of the low-permeability layer or the acid-scavenging medium layer includes an anti-fragmentation material.

[0014] Optionally, the acid-scavenging layer includes an intumescent material. Optionally, the semi-permeable membrane is a non-woven flash-spun fabric.

[0015] Optionally, the acid-scavenging medium layer is configured to cool a battery that is on fire and which is adjacent, in, or under the device.

[0016] Optionally, the acid-scavenging medium layer is configured to conform to a battery that is on fire and which is adjacent, in, or under the device and to a substrate adjacent the deviceOptionally, the acid-scavenging medium layer is configured to capture and neutralize harmful gases from the battery fire.

[0017] Optionally, the acid-scavenging medium layer includes a water gel.

[0018] Optionally, the acid-scavenging medium layer is configured to create a thermally stable insulator tending to prevent burn-through in the fire-mitigation device once the cooling potential of the water gel has been depleted.

[0019] Optionally, the water gel includes additives that enhance gelling and shear-thickening.

[0020] Optionally, the water gel includes charring and blowing agents.

[0021] Optionally, the water gel includes a nonwoven high loft fabric.

[0022] Optionally, the high loft fabric comprises natural and synthetic fibers with thermoplastic or crosslinked binders.

[0023] Optionally, the high loft fabric includes ceramic fibers, glass fibers, cellulosic fibers, organic-inorganic hybrid fibers, or oxidized polyacrylonitrile.

[0024] Optionally, the low-permeability anti-fragmentation layer is configured to stop shrapnel and fragments from battery explosion.

[0025] Optionally, the low-permeability layer comprises ballistic nylon or silicone impregnated glass fabric.

[0026] Optionally, the low-permeability layer comprises an elastomeric coating configured to enhance blast-resistance and reduce gas permeability of the low-permeability layer.

[0027] Optionally, the low-permeability layer comprises acid scavengers treated with surface modifiers configured to enhance coating flexibility.

[0028] Optionally, the fire-mitigation device includes a seam along an outer perimeter of the low-permeability layer and semi-permeable membrane joining the low-permeability layer to the semi-permeable membrane.

[0029] Optionally, the acid-scavenging medium layer is dehydrated.

[0030] The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.

[0031] Brief Description of the DrawingsFIG. 1 shows a cross-sectional schematic illustration of an exemplary firemitigation device in the form and size of a fire blanket and includes a 3-layered design.

[0032] FIG. 2 shows the exemplary fire-mitigation device in the process of mitigating a battery fire with the middle layer activated and processing the fire off-gassing.

[0033] FIG. 3 shows an exemplary fire mitigation device in the form of a sealable bag.

[0034] Detailed Description

[0035] As the use of lithium-ion batteries continues to grow in various devices and appliances — such as electric scooters, electric vehicles, powered tools, tablets, lawn mowers, and power backups — the risk of thermal runaway in domestic environments is increasing rapidly. This underscores the urgent need for affordable and easily deployable fire-suppressing technologies. Exemplary blankets, made from low-cost materials, addresses this need by cooling the battery, neutralizing acidic and toxic gases, and mitigating explosion risks. It can be shipped and stored dry, allowing users to simply add water upon receipt, making it both convenient and easy to deploy.

[0036] Referring first to FIG. 1 , an exemplary fire-mitigation device is shown at 100. The device 100 may be flexible and take the general form and size of a fireblanket. It features a layered design, with each layer serving a specific function. In exemplary uses, a device 100 may be placed, thrown, or otherwise deployed on to a battery 180 that is on a substrate 190 (a floor or table, e.g.).

[0037] The device 100 may include a semi-permeable membrane 110. The semi-permeable membrane 110 may be made of one or more materials that allow water vapor and gases to pass through while blocking water. In particular, the semi-permeable membrane 110 may be made of any one or more film or fabric which is impermeable to water and permeable to water vapor and / or have a low melting temperature below 200 °C or preferably below 140 °C. Materials suitable for this application include non-woven polypropylene fabrics, hydrophobic mesh materials, nanofiber membranes and microporous polyethylene (PE) films (e.g., Tyvek), for example. Exemplary embodiments may use microporouspolyethylene which may provide an ideal combination of properties due to good air permeability and low melting temperature combined with a relatively low cost.

[0038] However, a semi-permeable membrane (such as Tyvek or the like) will not retain water for an extended period. There are two possible approaches:

[0039] 1. Store the blanket inside a bag with low water vapor permeability, such as polyethylene, until it is ready for use.

[0040] 2. Include a refill port in the blanket to add water once it reaches its destination or point of deployment.

[0041] The second option allows the blanket to be shipped dry, reducing shipping and storage costs — particularly advantageous for large blankets due to their weight. It also makes handling and positioning the blankets easier for firefighters before adding water. Water could then be supplied directly from a fire hydrant immediately after deployment in a battery fire.

[0042] The fire-mitigation device 100 may include an acid-scavenging medium layer 120. This medium layer 120 may include, one or more intumescent materials and may include, for example, a water gel. The medium layer 120 may be configured to: (1) cool the battery; (2) conform to the battery and the substrate; (3) capture and neutralize harmful gases like HF, HCI and HCN; and / or (4) create a thermally stable insulator to prevent burn-through in the firemitigation device 100 once the cooling potential of the water gel has been depleted.

[0043] This medium layer 120 may comprise water containing gelling additives and one or more additives from each of one or more of charring agents, blowing agents, acid scavengers, and / or shear-thickening agents.

[0044] Exemplary gelling additives include, for example, starch, gelatin, alginates, laponite, cellulose derivatives like hydroxy-Zcarboxy- or methylcellulose, or the like.

[0045] Charring agents may promote carbonization of the medium at high temperature. Exemplary charring agents may include, for example, monoammonium phosphate, diammonium phosphate, or the like.

[0046] Blowing agents (like sodium bicarbonate or the like) may promote the formation of a porous residue with low thermal conductivity.

[0047] Acid scavengers may react with acidic gases released during thermalrunaway. Exemplary acid scavengers may include, for example, sodium bicarbonate, calcium carbonate, calcium gluconate, or the like.

[0048] Shear-thickening agents (which may also act as a gelling agent) may help absorb and / or dissipate energy (blast wave mitigation) in the event of battery fragmentation. Exemplary shear-thickening agents may include, for example, starch, laponite, or the like.

[0049] The acid-scavenging medium layer 120 may include a high-loft nonwoven fabric. Such a fabric may promote a constant given thickness of the acidscavenging layer throughout the blanket, have an anti-blast action to potentially allow the minimization or removal of a separate anti-blast layer. In such an exemplary embodiment, a high-loft nonwoven fabric, water, acid scavenging agents and optionally intumescent agents would be contained between a semi-permeable layer and a low-permeability anti-blast layer. Examples of fiber materials used for the high-loft nonwoven are ceramic fibers, glass fibers, hybrid fibers (like Visil fibers, or the like), and oxidized polyacrylonitrile.

[0050] An exemplary formulation may contain, for example, a minimum of 50% by mass of water and up to 20% by mass starch, 10% laponite, 10% monoammonium phosphate, 20% sodium bicarbonate. A preferred formulation contains between 70 and 80% water, 5 to 10% starch, 5 to 8% laponite, 5 to 10% monoammonium phosphate and 5 to 10% sodium bicarbonate. In other exemplary embodiments, the device 100 may include a dehydrated formulation that is hydrated by an end user.

[0051] The fire-mitigation device 100 may include a low-permeability (and optionally, anti-fragmentation) layer 130. This layer 130 may be made of a specialty fabric (e.g., ballistic nylon, silicone impregnated glass fabric (used as welding blankets), or the like) configured to stop shrapnel and fragments from battery explosion. The fabric may be rubberized with an elastomeric coating to enhance its blast-resistance and reduce gas permeability. The coating may also contain acid scavengers treated with surface modifiers to enhance coating flexibility. Exemplary fibers for use in the anti-fragmentation layer 130 include aramid fibers, ultra-high molecular weight polyethylene, polyamides, ceramic fibers, carbon fibers and / or a combination thereof.However, in some embodiments, the nonwoven fabric within the acidscavenging medium layer 120 can act as an anti-fragmentation layer. In this case the low-permeability layer 130 could be a non-gas-permeable material without anti-fragmentation properties.

[0052] The seam 105 of an exemplary fire-mitigation device 100 may be formed by any type of joining known to those skilled in the art, such as, for example, adhesively joining or welding the outer layers 110, 130 to each other to form a bag holding the middle layer 120 therebetween. The seam 105 may be continuous or discontinuous and may include a plurality of joins for redundancy. In embodiments where the semi-permeable membrane and the antifragmentation layer are made of different materials and / or cannot otherwise be easily sealed together by heat welding (pressure and heat) or other methods known in the art, water gel may be contained inside a bag made of semi-permeable membrane which is a thermoplastic. The anti-fragmentation layer may then be sewed over the edges of the blanket or glued to the semi-permeable membrane. The seam may be at the farthest lateral extent of the firemitigation device, forming its outer boundary, or, as shown in FIG. 1, may be laterally inward from the outer extent of the fire-mitigation device 100, with the anti-fragmentation layer 130 being smaller than the semi-permeable membrane 110, thereby allowing vapors to be released more readily from the edges of the fire-mitigation device than if the proportions of the layers 110, 130 were equal or reversed.

[0053] As mentioned above, in some embodiments, the fire-mitigation device 100 may be manufactured and shipped without water which could be added by an end user, thereby reducing manufacturing and shipping costs by reducing manufacturing complexity and reducing the size and weight of the fire-mitigation device 100 for shipping. In such cases, the fire-mitigation device 100 may include an optional port (not shown) for filling the fire-mitigation device 100 with water.

[0054] Turning now to FIG. 2, in the event of thermal runaway, the semi-permeable membrane 110 may be configured to melt and release the water gel of the middle layer 120 over the battery 180. The water gel may conform to the battery’s surface, enhancing cooling through water evaporation. As hot gases160 vent from the battery 180, they may cause the water gel to undergo localized intumescence, forming a foam-like residue with excellent thermal insulation properties. The foam residue, with its high surface area, may facilitate heterogeneous reactions between the acidic gases and the acid scavengers embedded in the residue. The delaminated laponite that may be within the water gel may stabilize the char intumescence and ensure effective thermal insulation, even in the oxidizing atmosphere and high temperatures characteristic of thermal runaway. The evolved gases can react with the acid scavengers in both the condensed phase within the expanded residue and the liquid phase within the water gel.

[0055] The low-permeability anti-fragmentation fabric 130 may prevent the gases from escape until they reach the lateral edges of the fire-mitigation device 100, promoting acid gas neutralization across a large volume.

[0056] Turning now to Fig. 3, an exemplary embodiment of the fire mitigation device is shown at 300. The fire mitigation device 300 is substantially the same as the above-referenced fire mitigation device 100, and consequently the same reference numerals but indexed by 200 are used to denote structures corresponding to similar structures in the fire mitigation devices. In addition, the foregoing description of the fire mitigation device 100 is equally applicable to the fire mitigation device 300 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the fire mitigation devices may be substituted for one another or used in conjunction with one another where applicable.

[0057] The exemplary fire mitigation device 300 takes the form of a bag, sleeve, or pouch, which, in at least some situations (such as, for example, for mitigation of fires from consumer electronics such as cellphones, laptops, tablets, or the like) may be more effective than a blanket. The semi-permeable layer inner layer 310 may line the inside of the bag and face the item on fire (not shown). Low-permeability anti-fragmentation fabric outer layer 330 may line the outside of the bag and wholly or partially contain any fumes / gasses / particulates coming from the fire. The acid-scavenging layer 320 may be disposed between the outer layer 330 and the inner layer 310. A bag-closure device 312 such as hook-and-loop fasteners or a slider zipper on an open end 305 may be used to wholly or partially seal the bag after inserting the item on fire.

[0058] Embodiments of the invention promise several significant benefits for residential, commercial, and industrial environments where lithium-ion batteries are commonly used:

[0059] o Enhanced Safety: Reduces the risk of toxic and acidic gas exposure, improving safety for both people and property.

[0060] o Cost-Effectiveness: Lowers the cost of fire blankets, facilitating widespread adoption.

[0061] o Improved Firefighting: Increases firefighting effectiveness by minimizing injury risk and property damage.

[0062] o Reduced Hazardous Agents: Limits the use of harmful extinguishing agents.

[0063] o Lower Environmental Impact: Minimizes the release of corrosive and toxic substances, as well as hazardous extinguishing agents.

[0064] o Economic Benefits: Decreases property damage, repair costs, insurance premiums, and financial losses.

[0065] Notably, firefighters would be able to deploy the blanket / fire-mitigation device without approaching the battery during thermal runaway, thereby avoiding exposure to potential explosions and fragmentation. Automated deployment systems for lithium-ion fires in residential garages, public indoor parking areas, and outdoor settings could include the deployment of exemplary fire-mitigation devices.

[0066] While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. Embodiments herein can be used independently or can be combined.

[0067] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The ranges are continuous and thus contain every value and subset thereof in the range.

[0068] Unless otherwise stated or contextually inapplicable, all percentages, when expressing a quantity, are weight percentages. The suffix (s) as used herein isintended to include both the singular and the plural of the term that it modifies, thereby including at least one of that term (e.g., the colorant(s) includes at least one colorants). Option, optional, or optionally means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not. As used herein, combination is inclusive of blends, mixtures, alloys, reaction products, collection of elements, and the like.

[0069] As used herein, a combination thereof refers to a combination comprising at least one of the named constituents, components, compounds, or elements, optionally together with one or more of the same class of constituents, components, compounds, or elements.

[0070] All references are incorporated herein by reference.

[0071] The use of the terms “a,” “an,” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. It can further be noted that the terms first, second, primary, secondary, and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. For example, a first current could be termed a second current, and, similarly, a second current could be termed a first current, without departing from the scope of the various described embodiments. The first current and the second current are both currents, but they are not the same condition unless explicitly stated as such.

[0072] The modifier about used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). The conjunction or is used to link objects of a list or alternatives and is not disjunctive; rather the elements can be used separately or can be combined together under appropriate circumstances.

[0073] Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations andmodifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

ClaimsWhat is claimed is:

1. A fire-mitigation device for lithium-ion battery fires comprising: a low-permeability layer;a semi-permeable membrane; andan acid-scavenging medium layer disposed between the low-permeability layer and the semi-permeable membrane,wherein at least one of the low-permeability layer or the acid-scavenging medium layer includes an anti-fragmentation material.

2. The fire-mitigation device of claim 1 , wherein the acid-scavenging layer includes intumescent material.

3. The fire-mitigation device of claim 1 , wherein the semi-permeable membrane includes a film or fabric having a melting temperature below about 200 °C.

4. The fire-mitigation device of claim 1 , wherein the semi-permeable membrane includes a film or fabric having a melting temperature below about 140 °C.

5. The fire-mitigation device of claim 1 , wherein the semi-permeable membrane includes microporous polyethylene.

6. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer is configured to cool a battery on fire and adjacent, in, or under the device.

7. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer is configured to conform to a battery on fire and adjacent, in, or under the device and to a substrate adjacent the device8. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer is configured to capture and neutralize harmful gases from the battery fire.

9. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer includes a water gel.

10. The fire-mitigation device of claim 9, wherein the acid-scavenging medium layer is configured to create a thermally stable insulator tending to prevent burn-through in the fire-mitigation device once the cooling potential of the water gel has been depleted.

11. The fire-mitigation device of claim 9, wherein the water gel includes additives that enhance gelling and shear-thickening.

12. The fire-mitigation device of claim 9, wherein the water gel includes charring and blowing agents.

13. The fire-mitigation device of claim 1 , wherein the low-permeability layer is an anti-fragmentation layer configured to stop shrapnel and fragments from battery explosion.

14. The fire-mitigation device of claim 1, wherein the low-permeability layer comprises ballistic nylon or silicone impregnated glass fabric.

15. The fire-mitigation device of claim 1 , wherein the low-permeability layer comprises an elastomeric coating configured to enhance blast-resistance and reduce gas permeability of the low-permeability layer.

16. The fire-mitigation device of claim 1 , wherein the low-permeability layer comprises acid scavengers treated with surface modifiers configured to enhance coating flexibility.

17. The fire-mitigation device of claim 1 , further comprising a seam along an outer perimeter of the low-permeability layer and semi-permeable membrane joining the low-permeability layer to the semi-permeable membrane.

18. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer is dehydrated.

19. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer includes 50% by mass of water and up to 20% by mass starch, 10% laponite, 10% monommonium phosphate, 20% sodium bicarbonate.

20. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer includes between 70 and 80% water, 5 to 10% starch, 5 to 8% laponite, 5 to 10% monoammonium phosphate and 5 to 10% sodium bicarbonate.

21. The fire-mitigation device of claim 1 , wherein the acid-scavenging medium layer includes a nonwoven high loft fabric.

22. The fire-mitigation device of claim 21 , wherein the high loft fabric comprises natural and synthetic fibers with thermoplastic or crosslinked binders.

23. The fire-mitigation device of claim 21 , wherein the high loft fabric comprises ceramic fibers, glass fibers, cellulosic fibers, organic-inorganic hybrid fibers, or oxidized polyacrylonitrile.

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