Initiating combustion of rechargeable lithium batteries in unmanned electronic devices

Abstract

Systems and methods for initiating combustion of a rechargeable lithium battery that powers an unmanned electronic device. A cell status regulator coupled to the battery is configured to change a status of a selected initiating cell of the battery by modifying at least one electrical or thermal characteristic of the initiating cell in response to a triggering event, the changed status resulting in initiating an internal short circuit in the cell, triggering a thermal runaway process, and battery combustion, thereby damaging at least one target portion of the device. Initiating the changing state of the battery cell may include heating, overcharge, reverse polarity, external short circuit, or forced discharge. Heating may be applied using a heating element powered by electrical energy extracted from the at least one battery cell. The trigger event may be receiving an activation signal from a remote activator or detecting an initiation condition according to a preloaded instruction.

Description

Technical Field

[0001] The present invention relates generally to battery powered electronic devices and, in particular, to the controlled destruction of unmanned electronic devices powered by rechargeable lithium type batteries. Background Art

[0002] Rechargeable lithium batteries are a type of rechargeable battery commonly used in electronic products. Lithium batteries are characterized by very high energy density relative to other types of rechargeable batteries, for example more than double the energy density of some nickel metal hydride batteries. Lithium-ion battery cells typically include a metal oxide, sulfur, iron phosphate-based, or air cathode; a lithium titanate anode that is usually graphite-based (sometimes combined with varying amounts of silicon) or carbon-based; and an electrolyte from an organic solvent. The anode and cathode react reversibly with lithium ions during charging and discharging. Rechargeable lithium batteries are also valued for their high power density, high quality performance over a wide temperature range, and low self-discharge rate. In addition, rechargeable lithium batteries are suitable for a variety of battery cell designs and configurations (e.g., prismatic, cylindrical, flat, coin, or pouch designs), as well as liquid organic electrolytes, solid electrolytes, and polymer electrolytes.

[0003] Rechargeable lithium batteries are also known for their tendency to ignite or explode under certain conditions. This phenomenon is usually caused by electrical faults, especially internal short circuits, which can be caused by the accumulation of latent defects and / or operational defects. Latent defects may involve the presence of contaminants or manufacturing defects, which may cause physical contact between the anode and cathode or their respective current collectors. Operational defects may include, for example: the growth of lithium dendrites caused by lithium metal plating in the battery; the growth of copper dendrites caused by copper plating (when the battery cell uses copper current collectors); tears or holes formed in the separator due to physical or thermal stress, which creates an opportunity for the anode and cathode to make physical contact; and manufacturing defects during the assembly of the battery cell. Short circuits in lithium battery cells can also be caused by degradation and environmental impacts, such as physical shock (such as dropping or vibration), large temperature fluctuations, physical shock, etc. An internal (or external) short circuit triggers an exothermic chain reaction of chemicals in the battery cell. This may cause a rapid increase in temperature, which can decompose the electrolyte to produce flammable gases, and thus cause pressure accumulation in the battery cell, causing the battery cell to swell or rupture, and may also cause the metal oxide cathode to decompose. The combination of the heat generated, the decomposition of the metal oxide cathode, and the flammable components of the electrolyte (in either decomposed or raw form) can cause the battery cell to burn or catch fire, and in some cases explode. The combustion can then propagate to other cells in a multi-cell module or pack, causing the entire battery to explode or catch fire.

[0004] Rapid self-heating of a battery cell driven by an exothermic reaction of the cell materials releasing stored energy, where the temperature increase accelerates the reaction, in turn causing further temperature increases in a positive feedback loop, describes a process known as "thermal runaway". At a critical temperature, thermal runaway can cause a sudden increase in the temperature of the battery cell, resulting in combustion. In the event of a short circuit, the internal temperature of a lithium battery cell can rise to unsafe levels in just a few seconds, resulting in thermal runaway and subsequent combustion, which may propagate to surrounding cells. Because rechargeable lithium batteries are more reactive and less thermally stable than other types of batteries, they are more susceptible to thermal runaway under certain conditions. These conditions may include: high temperature operation (e.g., above 80°C) or overcharging (e.g., high rate charging at low temperatures); conditions that may produce internal short circuits, such as lithium plating or copper plating; and / or manufacturing defects or defects caused by use, misuse, or abuse. At high temperatures, the cathode decomposes to produce oxygen, which reacts exothermically with organic materials in the battery cell (e.g., flammable organic solvent electrolyte and carbon anode). The highly exothermic chain reaction is very rapid and can lead to thermal runaway, reaching excessive temperatures and pressures (e.g., 700°C to 1000°C and about 500 psi) in just a few seconds. Once the chain reaction begins, it cannot be effectively stopped or extinguished, eventually leading to battery cell combustion (which in turn causes a propagation effect of the battery cell) and resulting in the combustion of the entire battery.

[0005] In summary, an initial internal fault or defect in a rechargeable lithium battery cell may trigger an internal short circuit, which in turn causes heating and a subsequent exothermic chain reaction, leading to irreversible thermal runaway and ultimately combustion / explosion. Cell heating due to high ambient temperature, rapid charging, high-load discharge, and the proximity of adjacent cells in a battery pack are all factors that increase the likelihood of thermal runaway.

[0006] As a result, a wide range of rechargeable lithium battery-powered devices, from laptops and cell phones to electric or hybrid cars, present serious safety risks, with frequent reports of hazardous incidents and multiple product recalls. The risk of such incidents is rising as the requirements for performance and size of battery cells and battery packs continue to increase, battery cell energy density is increasing, and rechargeable lithium battery cells are becoming more common in commercial products. Lithium battery cells may burn without any prior warning even under normal use. Therefore, many manufacturers try to minimize or prevent the possibility of lithium battery combustion in various ways, such as by using diagnostic tools and ensuring appropriate storage and operating conditions for the equipment. Some devices contain protection mechanisms for rechargeable lithium batteries at the battery cell or battery pack level to prevent overcharging, overdischarging, overheating, short circuiting, or other potentially dangerous conditions. For example, some mechanisms may terminate the battery current if specific operating limits are exceeded. However, in specific circumstances, it may be desirable to actively destroy or damage the electronic device powered by the lithium battery. Such destruction needs to be carried out in a safe, controlled and reliable manner while avoiding damage to individuals and surrounding property. For example, the electronic device may contain sensitive or secret information and / or confidential materials or components that need to be kept away from unauthorized parties. The device may be located in a remote location or in a location with limited or difficult-to-access access, which may complicate the ability to remove confidential information or materials from the device and / or render it unusable, undecryptable, and / or inaccessible. Summary of the invention

[0007] According to one aspect of the present invention, a method for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device is provided. The method includes the following steps: in response to a triggering event, changing the state of a selected initiating cell of the rechargeable lithium battery, the changed state causing an internal short circuit in the initiating cell, triggering a thermal runaway process and combustion of the battery for damaging at least a target portion of the device. Changing the state of the selected initiating cell of the battery may include: using energy from the battery to modify at least one electrical characteristic or thermal characteristic of the initiating cell by a cell state regulator connected to the battery. Changing the state of the selected initiating cell of the battery may include at least one of the following actions: externally heating the initiating cell; overcharging the initiating cell; applying reverse polarity to the initiating cell; applying an external short circuit to the initiating cell; or applying a forced discharge to the initiating cell. Externally heating the initiating cell may include: applying heat to the initiating cell by a heating element connected to at least a portion of the initiating cell, the heating element being powered by electrical energy extracted from at least one cell of the battery. The method may also include a preliminary step of selecting a means for inducing an internal short circuit in the initiating cell to trigger thermal runaway according to at least one parameter or condition. The method may also include a preliminary step of selecting an initiating cell based on at least one parameter or condition. The initiating cell may be selected based on at least one of the following parameters: a maximum power output available from at least one cell of the battery; a minimum energy required to induce thermal runaway in at least one cell of the battery; and a maximum damage distance related to the size of the battery. The triggering event may include receiving an activation signal from a remote activator. The triggering event may include detecting at least one initiating condition based on preloaded instructions in the device. The device may include an unmanned vehicle.

[0008] According to another aspect of the present invention, a system for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device is provided. The system includes a cell state regulator, which is coupled to the rechargeable lithium battery and configured to, in response to a triggering event, change the state of a selected initiating cell of the rechargeable lithium battery, the changed state causing an internal short circuit in the initiating cell, triggering a thermal runaway process and combustion of the battery, for damaging at least a target portion of the device. The cell state regulator may be configured to change the state of the selected initiating cell by modifying at least one electrical characteristic or thermal characteristic of the selected initiating cell using energy from the battery. Changing the state of the selected initiating cell of the battery may include at least one of the following actions: externally heating the initiating cell; overcharging the initiating cell; applying reverse polarity to the initiating cell; applying an external short circuit to the initiating cell; or applying a forced discharge to the initiating cell. The cell state regulator may include a heating element coupled to at least a portion of the initiating cell, the heating element configured to heat the initiating cell from the outside, the heating element being powered by electrical energy extracted from at least one cell of the battery. The system may also include at least one sensor configured to detect at least one parameter of the battery, wherein the state of the triggering battery cell changes according to the detected parameter. The system may also include a processor configured to select a manner for causing an internal short circuit in the triggering battery cell to trigger thermal runaway according to at least one parameter or condition. The system may also include a processor configured to select a triggering battery cell according to at least one parameter or condition. The triggering battery cell may be selected based on at least one of the following parameters: a maximum power output available from at least one battery cell of the battery; a minimum energy required to trigger thermal runaway in at least one battery cell of the battery; and a maximum damage distance related to the size of the battery. The system may also include a remote activator, the remote activator being communicatively coupled to the device and configured to send an activation signal to the device, wherein the triggering event includes receiving the activation signal from the remote activator. The triggering event may include detecting at least one triggering condition according to instructions preloaded in the device. The device may include an unmanned vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be more fully understood and appreciated from the following detailed description in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a schematic diagram of a system for initiating combustion of a rechargeable lithium battery for powering unmanned electronic devices, constructed and operative in accordance with an embodiment of the present invention;

[0011] Figure 2 is a diagrammatic representation of an exemplary arrangement of a system for initiating combustion of a rechargeable lithium battery using an external heating method, constructed and operative in accordance with an embodiment of the present invention;

[0012] Figure 3A is an illustration of a first exemplary configuration of an initiating cell in a rechargeable lithium battery pack constructed and operative in accordance with an embodiment of the present invention;

[0013] Figure 3B is an illustration of a second exemplary configuration of an initiating cell in a rechargeable lithium battery pack constructed and operative in accordance with an embodiment of the present invention;

[0014] Figure 4 is a schematic diagram of thermal runaway propagation leading to explosion in a battery pack operated according to an embodiment of the present invention; and

[0015] Figure 5 is a flow chart of a method for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device, operated in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present invention overcomes the shortcomings of the prior art by providing a novel method and system for actively implementing controlled damage to unmanned electronic devices powered by rechargeable lithium batteries by initiating combustion of the lithium battery. The disclosed method and system can induce an irreversible thermal runaway process in a device battery by changing the state of at least one battery cell of the battery (e.g., by modifying at least one electrical characteristic or thermal characteristic of the battery cell), thereby causing an induced (i.e., non-spontaneous) combustion of the battery and subsequent damage or destruction of the electronic device powered by the battery. For example, an external heating element proximate to one of the battery cells in a multi-battery cell lithium battery can be intended to use electrical energy from other battery cells in the battery pack to heat the closest battery cell. The operating voltage of the heating element can be scaled to the voltage of the battery cell group from which the electrical energy is obtained. The triggering event that activates the initiation of battery cell combustion can include receiving a trigger signal from a remote source, or detecting a selected trigger condition by the device itself.

[0017] The present invention will be apparent from the following detailed description made with reference to the accompanying drawings, wherein like reference numerals refer to like elements. In order to better understand specific embodiments and to show how to implement these embodiments, reference will now be made to the accompanying drawings by way of example only, wherein like numerals always represent corresponding elements or parts.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms "include" or "comprise" when used in this specification specify the presence of the features, integers, steps, operations, elements, components, and / or groups or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups or combinations thereof. As used herein, the terms "include", "comprises", "has", and their anagrams mean "including but not limited to". The term "consisting of" means "including and limited to".

[0020] As used herein, the term "and / or" includes any and all possible combinations or one or more of the associated listed items, as well as the lack of a combination when interpreted in the alternative ("or").

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having the same meaning as they have in the context of the specification and claims, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0022] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. Instead, these terms are only used to distinguish one element, component, region, layer and / or part from another element, component, region, layer and / or part.

[0023] It should be understood that when an element is referred to as being "on another element", "attached to" another element, "operably coupled to" another element, "operably connected to" another element, "operably engaged to" another element, "connected to" another element, "coupled to" another element, "contacting" another element, "added to" another element, etc., the element can be directly on, attached to, connected to, operably coupled to, operably engaged to, coupled to, added to, and / or contacting another element, and other elements or intermediate elements may also be present. In contrast, when an element is referred to as being "directly in contact with" or "directly added to" another element, there are no intermediate elements and / or steps.

[0024] Whenever the term "about" is used, it refers to a measurable value, such as an amount, a duration of time, etc., and is intended to encompass variations from the specified value as such variations are suitable for performing the disclosed methods.

[0025] For the sake of clarity, certain features of the invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of brevity, various features of the invention described in the context of a single embodiment may also be provided separately or in any suitable sub-combination or in any suitable manner in any other described embodiment of the invention. Certain features described in the context of various embodiments should not be considered essential features of those embodiments, unless the embodiment cannot be implemented without those elements.

[0026] Whenever the terms "plurality" and "multiple" are used, they are intended to include, for example, "plurality" or "two or more". The terms "plurality" or "multiple" may be used throughout the specification to describe two or more components, devices, elements, units, parameters, etc. A set of terms may include one or more items when used herein. Unless explicitly stated, the method embodiments described herein are not limited to a particular order or sequence. In addition, some of the method embodiments or elements thereof may occur or be performed simultaneously, at the same point in time, or concurrently.

[0027] As used herein, the term "method" refers to ways, means, techniques and procedures for accomplishing a given task, including but not limited to ways, means, techniques and procedures that are known or readily developable from known ways, means, techniques and procedures.

[0028] Throughout the disclosure, references to "disclosed embodiments," "disclosed systems," and "disclosed methods" refer to examples of the inventive ideas, concepts, and / or manifestations described herein. Many related and unrelated embodiments are described throughout the disclosure. Some "disclosed embodiments" are described as exhibiting a feature or characteristic, but this does not mean that other disclosed embodiments necessarily share the feature or characteristic.

[0029] The present disclosure uses open licensing language, for example, indicating that some embodiments "may" employ, involve, or include a particular feature. The use of the term "may" and other open terms is intended to indicate that, although not every embodiment may employ the features of the particular disclosure, at least one embodiment employs the features of the particular disclosure.

[0030] The terms "user" and "operator" are used interchangeably herein to refer to any individual or group of people who use or operate a method or system according to embodiments of the present invention, such as a person performing a controlled combustion of an unmanned electronic device.

[0031] As used herein, the general term "battery" and the specific term "lithium battery" or "rechargeable lithium battery (RLB)" refer to any lithium-based rechargeable battery comprising any number of electrochemical cells (or groups of cells) connected in any configuration (e.g., in series, in parallel, and a combination of series and parallel), including batteries of single cells, and comprising all types of cell form factors (e.g., including but not limited to: cylindrical, prismatic, pouch, coin, and button cells), sizes, and cell designs (e.g., including but not limited to: jelly roll design cells, bobbin cells, cells with Z-folded electrodes, cells with dog-bone folded electrodes, cells with elliptical folded electrodes, and parallel plate stacked electrode cells, whether bipolar or not). LIBs typically include at least one pair of electrodes (anode, cathode), an electrolyte (liquid, solid, semi-solid, and / or polymer) for conducting lithium ions, and a separator. The battery may be integrated with or form part of at least one electrical or electronic device or component (e.g., including but not limited to at least one of the following: a capacitor; a supercapacitor; a printed circuit board (PCB); a semiconductor device, an electronic device, a passive electronic component, a battery management system; an electronic control unit; a power adapter; a charger; a wireless charging system; a fuse; a sensor; a positive temperature coefficient (PTC) device; a current interrupt device (CID); and any combination thereof). The terms "battery" and "battery pack" are used interchangeably herein. It is worth noting that "lithium battery" herein covers lithium metal rechargeable batteries, lithium ion (Li-ion) rechargeable batteries, and lithium ion polymer rechargeable batteries, as well as batteries of these types, including but not limited to: reserve batteries, thermal batteries, so-called lithium ion capacitors, lithium air, and lithium sulfur batteries. The disclosed embodiments are applicable to all types of rechargeable lithium battery chemistries, including but not limited to cathodes whose active materials are based on nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LCO), lithium ion manganese oxide (LMO), sulfur and lithium iron phosphate (LFP) (each cathode within the effective stoichiometric range), and anodes whose active materials are based on graphite, hard carbon, soft carbon, lithium titanate (LTO), lithium metal, silicon, silicon-carbon composites, silicon-graphite composites, and tin.

[0032] The term "combustion" as used herein broadly covers all forms of destructive battery conditions following or caused by thermal runaway, including but not limited to lithium batteries and / or at least one of their battery cells at least partially experiencing: combustion, ignition, fire, explosion, ignition, rupture, electrolyte solution leakage, expansion, exhaust, etc.

[0033] The term "damage" as used herein broadly encompasses any form of damage, destruction, or destruction to an electronic device that renders at least a portion of the device (including but not limited to the electronic device, components, or data contained in the device) unusable, undecipherable, unrecognizable, and / or inaccessible.

[0034] Reference now Figure 1 , which is a schematic diagram of a system for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device, generally designated 100, constructed and operated in accordance with an embodiment of the present invention. System 100 is configured to effect controlled damage to an electronic device 120 powered by a lithium-ion battery 122 comprised of a plurality of battery cells 124. Device 120 is described herein as an unmanned aerial vehicle (UAV) or "drone" for exemplary purposes, but may alternatively represent different types of unmanned electric vehicles operating in any environment (e.g., air, land, or sea). More generally, the disclosed embodiments may be applied to any device powered by at least one multi-cell rechargeable lithium battery. Non-limiting examples may include: electric or hybrid vehicles, such as automobiles, buses, trucks, airplanes, or marine vessels; two- or three-wheeled electric / hybrid vehicles; electric bicycles (e-bikes); electric scooters; household appliances; electronic devices; medical devices; mobile devices; energy storage devices; uninterruptible power supplies; battery for charging devices; battery for charging electric vehicles; satellites; robots; and the like.

[0035] The system 100 includes an activator 115 of an operator unit 110 and a battery cell state regulator 126 of an electronic device 120. The operator unit 110 may be located remotely from the electronic device 120. The activator 115 is communicatively coupled to the battery cell state regulator 126 so as to be capable of transmitting (and optionally receiving) signals over any suitable data communication channel or network, using any type of channel or network model and any signal transmission protocol (e.g., wired, wireless, radio, WiFi, Bluetooth, etc.).

[0036] The operator unit 110 may be embodied by any type of electronic device having computing and signal transmission / reception capabilities, including but not limited to: a mobile computer; a desktop computer; a smart phone; a laptop computer; a netbook computer; a tablet computer; or any combination thereof. Alternatively, the operator unit 110 may be a basic remote control device, such as embodied by only an activator 115. It is noted that the system 100 may generally include multiple operator units operable by multiple respective users, although only a single operator unit 110 is depicted for exemplary purposes.

[0037] The activator 115 is configured to send an activation signal 117 to a battery cell state regulator 126 to trigger the activation of the initiated battery combustion. The activation signal 117 can be, for example, a radio frequency signal of any wavelength, or a wired or wireless communication signal. The battery cell state regulator 126 is configured to change the state of at least one battery cell 124 of the battery 122, which will be further described below.

[0038] The components and devices of system 110 may be based on hardware, software, or a combination thereof. It will be appreciated that the functionality associated with each of the devices or components of system 110 may be distributed across multiple devices or components, which may be located in a single location or in multiple locations. System 100 may optionally include Figure 1 Additional components not shown and / or Figure 1 The operating unit 110 may be associated with additional components, not shown, for enabling the disclosed subject matter. For example, the operating unit 110 may include: an electrical sensor (not shown) for detecting one or more electrical characteristics of the battery, such as a voltage or current measuring device; a processor (not shown) for receiving and processing information from other components, such as detected battery parameters; a user interface (not shown) for allowing a user to control various parameters or settings associated with the system 100; a memory or storage device (not shown) for storing information related to the operation of the system 100; a display device (not shown) for visually displaying information related to the operation of the system 100, and / or a camera or imaging device (not shown) for capturing images of the operation of the system 100.

[0039] The operation of the system 100 will now be described in general terms, followed by a description of specific examples. An authorized decision is made to implement controlled destruction of an unmanned electronic device 120. Specifically, an owner or operator of the device 120, or other individual authorized to make a decision to destroy it, decides to implement controlled destruction, such as to prevent unwanted access to confidential material contained in the device 120. After making the decision, the operator activates the initiation of combustion of the battery cell 124 by deploying the activator 115, such as by manual operation (e.g., by pressing a button or flipping a switch) or by inputting a command (e.g., through a touch screen user interface, or by providing a voice instruction in a voice recognition setting). The activator 115 can also be configured to receive instructions remotely, such as from: a service center, a monitoring station, and / or a remote server, application, or database in a cloud computing network, where the instructions can be provided in real time or at a predetermined, programmable, or spontaneous time (e.g., based on a set of rules).

[0040] Upon deployment, the activator 115 sends an activation signal 117 to the device 120. The battery cell state regulator 126 receives the activation signal 117 and initiates the combustion of the battery 122. The initiation may be performed immediately or upon the satisfaction of at least one initiation condition, such as a predetermined time in the future, environmental conditions in which the device is operating (e.g., weather or climate conditions), detection of the device by unauthorized parties, and / or based on at least one parameter of the battery 122 (e.g., state of charge, temperature, voltage). According to an embodiment of the present invention, the device 120 is preloaded with activation trigger instructions (i.e., without the need to receive an activation signal from the operating unit 110), such that the device 120 is programmed or configured to automatically initiate the battery combustion process if and when selected initiation conditions are satisfied, such as based on a predetermined time, based on environmental conditions (e.g., weather), based on unauthorized detection or access to the device 120, and / or based on at least one detected parameter of the battery 122.

[0041] To initiate combustion of the battery 122, the battery cell state regulator 126 changes the state of the selected battery cell 124 of the battery 122 to cause an internal short circuit and trigger the thermal runaway process. Specifically, the battery cell state regulator 126 modifies the initiating battery cell 124 i At least one electrical characteristic or thermal characteristic of the battery cell 124 i The triggering cell 124 may be a single cell or a group of cells in any position of the battery cell group. The triggering cell 124 may be selected based on various criteria. i For example, the selection criteria may include: triggering the battery cell 124 i Position or location within battery pack 122; triggering battery cell 124 i a proximity to at least one target object to be damaged in the device 120; and a type of battery cell and a size of the battery relative to a size of the target object.

[0042] The battery cell state regulator 126 can modify the triggering battery cell 124 i The changed state can be used to introduce one or more defects into the triggering battery cell 124. i , which causes an internal short circuit and triggers thermal runaway, resulting in battery cell 124 i Combustion. Initiation of battery cell 124 i The combustion of the battery 122 is propagated to other battery cells 124, which in turn undergo combustion, resulting in combustion of the battery 122 and damage to (at least the targeted portion of) the device 120. This propagation of combustion can be used to maximize the effectiveness of the damage caused by the device 120.

[0043] In one example, the battery cell state regulator 126 triggers the battery cell 124i External heating is applied to trigger thermal runaway. External heating can be triggered by proximity to the battery cell 124 i For example, the heating element may be coupled to the triggering battery cell 124 i The heating element may receive electrical energy extracted from other cells 124 of the battery 122 and direct the extracted energy in the form of heat to the inducing cell 124. i . External heating of an initiating battery cell can result in a high probability of internal short circuit and thermal runaway regardless of the state of the battery cell, but the time required to initiate a combustion may depend on several factors, such as the charge state of the initiating battery cell, the power rating of the heating element, and the power supplied to the heating element. The input voltage to the heating element is scaled to the voltage that can be provided by the battery cell from which the power is drawn. The heating element can be configured in an optimal position relative to the initiating battery cell in order to maximize the heating effect to initiate combustion. The geometry of the heating element can be adjusted to maximize the heat flow to the initiating battery cell. An increased power rating of the heating element generally shortens the time to initiate combustion. In general, the higher the charge state of the initiating battery cell, the greater the combustion force.

[0044] refer to Figure 2 , which is a diagram of an exemplary arrangement of a system for initiating combustion of a rechargeable lithium battery using an external heating method, constructed and operated according to an embodiment of the present invention. The arrangement includes a battery 132 composed of a plurality of battery cells 134, a heating element 136 coupled to the initiating battery cell 134 i In some cases, lithium batteries are separated from electronic device components by separators, for example for safety reasons. Figure 2 In the example of FIG. 1 , battery 132 is separated from target electronic device 130 (depicted as a printed circuit board (PCB) for exemplary purposes) by a separator 137 having a thickness “y” by a distance “x”. The destructive force of the triggered combustion event can be used to overcome the distance “x” and thickness “y” of separator 137. Battery 132 can be embodied, for example, by a lithium-ion battery pack having a 6S2P configuration with 18,650 battery cells. The triggering battery cells can be in any position. For example, Figure 3A The initiation battery cell (144) in the rechargeable lithium battery pack 142 having a 6S2P configuration is shown. i ) in a first exemplary configuration, wherein the battery cell 144 is triggered i Located at a corner of the battery pack 142. For another example, Figure 3B The initiation battery cell (154) in a rechargeable lithium battery pack 152 having a 6S2P configuration is shown. i ) in a second exemplary configuration, wherein the battery cell 154 is triggered iLocated at the middle edge of the battery pack 152. The location of the initiating cell (which may be a group of cells) may depend on the form factor of the cells in the battery pack, the location of the target portion of the device to be damaged, the design of the device, and other factors. The location of the initiating cell and its orientation relative to the propagating cell may be selected so as to maximize the effect of initiating combustion.

[0045] Upon activation, the heating element 136 provides a charge to the triggering cell 134. i Heat is applied. The applied heat causes the battery cell 134 to i The internal short circuit in the battery 132 triggers thermal runaway and combustion, which then propagates along other battery cells 134 in the battery 132. The combustion initiated can be configured to have sufficient force to ensure that the propagated combustion reaches all other battery cells 134 of the battery 132, or at least reaches multiple battery cells 134 of the battery 132. The operation of the heating element 136 can be achieved by extracting electrical energy from the battery cells 134 of the battery 132, which can include electrical energy from the initiating battery cell 134. i Thus, no external power source is required to operate the heating element, as all required power can be obtained internally from the battery 132.

[0046] In another example, the change in state of the induced battery cell is achieved by overcharging. Figure 1 The battery cell state regulator 126 may trigger the battery cell 124 i Overcharging is performed to trigger thermal runaway, for example by providing a charge to the triggering battery cell 124 i Delivers a constant current. This may require preliminary charging of the battery to a selected initial state of charge (SOC) before overcharging. Excessive electrical energy in the battery cell caused by overcharging causes heat generation and thermal runaway. Overcharging methods may result in a high probability of internal short circuits and thermal runaway. However, if the triggering battery cell is at a low state of charge, combustion may take a relatively long time. Overcharging may consume energy from other battery cells that are not used to trigger thermal runaway, and may cause venting, swelling, or rupture of the battery cell instead of combustion.

[0047] Another example of changing the state of the battery cell is related to the polarity of the battery cell. Specifically, the battery cell state regulator 126 can cause the battery cell 124 to i Applying reverse polarity to trigger thermal runaway, for example, first disconnects the battery cell 124, for example, via an external resistor. i Discharge the battery completely and then reverse the polarity of the battery cell 124 iRecharge. This method does not require preliminary charging of the battery 122, but may take a relatively long time to initiate combustion. Applying reverse polarity may consume energy from other battery cells that are not used to initiate thermal runaway.

[0048] In yet another example, the battery cell state regulator 126 may trigger the battery cell 124 i Apply an external short circuit to trigger thermal runaway, such as by connecting the positive and negative battery cell terminals to an external resistor. The external short circuit method may not always generate enough heat to cause thermal runaway or battery cell combustion, especially at low states of charge.

[0049] In yet another example, the battery cell state regulator 126 may trigger the battery cell 124 i Applying forced discharge to a low voltage or negative voltage (e.g., 0V) to trigger thermal runaway. The forced discharge method may take a relatively long time to initiate combustion and may consume energy from other battery cells that are not used to initiate thermal runaway.

[0050] Before the cell state changes, the triggering cell may need to undergo preliminary preparation. For example, it may be necessary to remove at least one protective component from the battery cell, such as a positive temperature coefficient (PTC) or a current interrupt device (CID). If the PTC is not removed, the cell state change may terminate before reaching combustion because the cell temperature will trigger the PTC to prevent current from flowing into the battery cell. If the CID is not removed, the cell state change may terminate before reaching combustion because the high cell current applied in the cell state change will trigger the CID to prevent current from flowing into the battery cell. It may also be necessary to apply a preliminary charge to the triggering cell to reach a selected state of charge (SOC) sufficient to trigger significant combustion. The preliminary charge can be optimized so that the battery cell reaches a sufficient SOC level as quickly as possible to maximize the energy available for combustion. The battery cell can then be subjected to external heating, overcharging, or other characteristic modifications intended to trigger thermal runaway and trigger combustion.

[0051] The series-parallel connections between the battery cells in the battery pack can be reconfigured around the time of the activation trigger of the initiating battery cell to optimize the battery pack current and voltage for a given thermal runaway generation method. MOSFET switching circuits can be used to isolate the initiating battery cell from the remaining battery cells in the battery pack and / or reconfigure the series-parallel connections to maximize the power provided to the initiating battery cell.

[0052] The cell state change may take into account relevant information, such as the initial state or characteristics of the battery 122, which may be obtained using one or more battery monitoring devices. For example, a processor (not shown) may determine the maximum power output that can be obtained from the selected cell, and / or may determine the minimum energy required to induce thermal runaway in the selected cell for evaluating the suitability of the selected cell as an initiating cell. The processor may evaluate several possible methods of inducing thermal runaway in the selected cell based on the received data, and may determine and select the best method, for example, to optimize combustion and / or maximize the likelihood and impact of damage to the target device portion.

[0053] Triggering battery cell 124 i The state change is intended to cause internal defects and internal short circuits, which lead to the initiation of battery cell 124 i The thermal runaway of the battery cell 124 eventually leads to its combustion. i The combustion of the battery 122 triggers the propagation of combustion in the adjacent battery cells 124 of the battery 122, which then propagates to other battery cells 124 until all (or at least a plurality of) battery cells 124 in the battery 122 are finally burned. Figure 4 , which is a schematic diagram of thermal runaway propagation leading to explosion within a battery pack operated according to an embodiment of the present invention. In a first stage 161, a battery pack is provided. In a second stage 162, a triggering cell (located in the lower left corner) undergoes a cell state change to cause an internal short circuit and trigger thermal runaway. In a third stage 163, the combustion of the triggering cell propagates to an initial first group of cells adjacent to the triggering cell. In the next stage 164, the combustion propagates to a larger group of cells adjacent to the first group. In the next stage 165, the combustion has propagated to almost all of the cells. In the final stage 166, the battery has exploded.

[0054] It will be appreciated that the disclosed embodiments may provide a reliable and secure technique for actively damaging unmanned electronic devices powered by rechargeable lithium batteries. The disclosed embodiments may provide enhanced security, such as by preventing the transfer of assets or confidential materials to unwelcome parties, and may expand mission capabilities in the case of drone devices. The disclosed embodiments may be implemented in a simple manner, using existing onboard batteries to produce an induced (non-spontaneous) combustion or explosion, resulting in targeted damage to electronic devices. The power required to induce battery combustion may come entirely from the battery itself, so no external power source is required. In addition, there is no need to reduce the payload or cargo size or weight of the device because the combustion source is the battery typically used to power the device, thereby eliminating the need to sacrifice characteristics of the device (e.g., the range of the drone device) in order to provide a mechanism to damage the device in a targeted manner to protect confidential information or materials contained onboard.

[0055] The following table provides experimental results of the embodiments of the present invention applied to different battery types under different conditions.

[0056]

[0057]

[0058]

[0059]

[0060] Table 1

[0061] Reference now Figure 5 , which is a flow chart of a method for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device operated in accordance with an embodiment of the present invention. In step 182, a triggering event for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device is detected. Figure 1 , the initiation of combustion of the battery 124 of the electronic device 120 is triggered by a triggering event, such as receiving the activation signal 117 from the external activator 115, or detecting at least one initiation condition according to preloaded instructions in the device 120 or after receiving the activation signal 117. The initiation condition may include a predetermined time, unauthorized detection or access to the device 120, at least one environmental condition; and / or at least one parameter of the battery 124.

[0062] At step 183, the state of the selected initiating cell of the lithium battery is changed to cause an internal short circuit in the initiating cell, thereby triggering a thermal runaway process and combustion of the battery. The state of the initiating cell may be changed by modifying at least one of its electrical or thermal characteristics. Figure 1 In response to the detected triggering event, the battery cell state regulator 126 modifies the triggering battery cell 124 of the battery 122 i The characteristics of the battery cell are changed to change its state. Inducing the battery cell state change can be achieved in various ways. In the first example (sub-step 184), the battery cell is heated by a heating element using electrical energy extracted from the battery cell in the battery. Figure 2 , the closest heating element 136 applies heat to the triggering battery cell 134 i , causing the triggering cell 134 i The operation of the heating element 136 is powered by electrical energy extracted from the battery cell 134 of the battery 132 (which may include electrical energy from the initiating battery cell 134). iThe operating voltage of the heating element can be scaled to the voltage of the battery cell from which the power is obtained. In the second example (sub-step 185), the battery cell is induced to undergo overcharging. Figure 1 The battery cell state regulator 126 triggers the battery cell 124 i Overcharging is performed, for example, by causing the battery cell 124 to i A constant current is delivered to cause an internal short circuit, triggering thermal runaway and combustion. In another example (sub-step 186), a reverse polarity is applied to the triggering battery cell. See Figure 1 The battery cell state regulator 126 triggers the battery cell 124 i Applying reverse polarity to trigger thermal runaway, for example by causing the triggering battery cell 124 i The battery cell 124 is then triggered by fully discharging (e.g., via an external resistor) and then reversing the polarity. i In another example (sub-step 187), an external short circuit is applied to the triggering battery cell. Figure 1 The battery cell state regulator 126 triggers the battery cell 124 i An external short circuit is applied to cause an internal short circuit, triggering thermal runaway and combustion, such as by connecting the positive and negative battery cell terminals to an external resistor. In yet another example (sub-step 188), the battery cell is induced to undergo a forced discharge. See Figure 1 The battery cell state regulator 126 triggers the battery cell 124 i Applying forced discharge to low or negative voltage to cause internal short circuit, triggering thermal runaway and combustion.

[0063] Due to its modified characteristics and changed state, the battery cell 124 is caused i An internal defect occurs, causing an internal short circuit, which leads to thermal runaway and battery cell combustion. i The combustion propagates to adjacent battery cells 124 of battery 122 and further battery cells 124, causing battery 122 to burn (and / or explode) and causing targeted damage to device 120, thereby rendering confidential information or materials contained in device 120 unusable, undecryptable and / or inaccessible.

[0064] While certain embodiments of the disclosed subject matter have been described to enable those skilled in the art to practice the invention, the foregoing description is intended to be exemplary only. It should not be used to limit the scope of the disclosed subject matter, which should be determined with reference to the following claims.

Claims

1. A method for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device, the method comprising the following steps: In response to a triggering event, the state of a selected triggering cell of the rechargeable lithium battery is changed, the changed state causing an internal short circuit in the triggering cell, triggering a thermal runaway process and combustion of the battery for damaging at least a target portion of the device.

2. The method of claim 1 , wherein changing the state of a selected triggering cell of the battery comprises: Energy from the battery is used to modify at least one electrical or thermal characteristic of the initiating cell via a cell state regulator coupled to the battery.

3. The method of claim 1 , wherein changing the state of the selected triggering cell comprises at least one action selected from the group consisting of: Initiate heating of the battery cell from the outside; Overcharging of the triggering battery cells; applying reverse polarity to the triggering cell; applying an external short circuit to the triggering cell; and Forced discharge is applied to the triggering cell.

4. The method of claim 3, wherein externally heating the initiation cell comprises: Heat is applied to the initiation cell via a heating element coupled to at least a portion of the initiation cell, the heating element being powered by electrical energy extracted from at least one cell of the battery.

5. The method of claim 1 further comprising a preliminary step of sensing at least one parameter of the battery, wherein a change in the state of the battery cell is initiated based on the sensed parameter.

6. The method of claim 1 further comprising a preliminary step of selecting a means for causing an internal short circuit in the initiating battery cell to trigger thermal runaway based on at least one parameter or condition.

7. The method of claim 1 further comprising a preliminary step of selecting an initiating cell based on at least one parameter or condition.

8. The method according to claim 7, wherein: The initiation cell is selected based on at least one parameter selected from the group consisting of: a maximum power output obtainable from at least one cell of the battery; a minimum energy required to induce thermal runaway of at least one battery cell in the battery; and Maximum damage distance related to battery size.

9. The method of claim 1, wherein the triggering event comprises receiving an activation signal from a remote activator.

10. The method of claim 1, wherein the triggering event comprises detecting at least one triggering condition according to instructions preloaded in the device.

11. The method of claim 1 , wherein the device comprises an unmanned vehicle.

12. A system for initiating combustion of a rechargeable lithium battery for powering an unmanned electronic device, the system comprising: A battery cell state regulator is connected to a rechargeable lithium battery and is configured to change the state of a selected triggering battery cell of the rechargeable lithium battery in response to a triggering event, the changed state causing an internal short circuit in the triggering battery cell, triggering a thermal runaway process and combustion of the battery, for damaging at least a target portion of the device.

13. The system of claim 12, wherein the cell state regulator is configured to change the state of the selected initiating cell by modifying at least one electrical characteristic or thermal characteristic of the selected initiating cell using energy from the battery.

14. The system of claim 12, wherein changing the state of the selected triggering cell comprises at least one action selected from the group consisting of: Initiate heating of the battery cell from the outside; Overcharging of the triggering battery cells; applying reverse polarity to the triggering cell; applying an external short circuit to the triggering cell; and Forced discharge is applied to the triggering cell.

15. The system of claim 14, wherein the battery cell state regulator includes a heating element coupled to at least a portion of the initiation battery cell, the heating element configured to externally heat the initiation battery cell, the heating element being powered by electrical energy extracted from at least one battery cell of the battery.

16. The system of claim 12, further comprising at least one sensor configured to detect at least one parameter of the battery, wherein a change in the state of the battery cell is induced based on the detected parameter.

17. The system of claim 12, further comprising a processor configured to select a manner for causing an internal short circuit in the initiating battery cell to trigger thermal runaway based on at least one parameter or condition.

18. The system of claim 12, further comprising a processor configured to select the initiation cell based on at least one parameter or condition.

19. The system of claim 18, wherein: The initiation cell is selected based on a parameter selected from the group consisting of: a maximum power output obtainable from at least one cell of the battery; a minimum energy required to induce thermal runaway of at least one battery cell in the battery; and Maximum damage distance related to battery size.

20. The system of claim 12, further comprising a remote activator communicatively coupled to the device and configured to send an activation signal to the device, wherein the triggering event comprises receiving the activation signal from the remote activator.

21. The system of claim 12, wherein the triggering event comprises detecting at least one triggering condition according to preloaded instructions in the device.

22. The system of claim 12, wherein the device comprises an unmanned vehicle.

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