Battery Protection at Altitude

Abstract

The battery assembly includes a first plurality of battery cells, a second plurality of battery cells, and a switch between the first and second plurality of battery cells. In one example, the first plurality of battery cells, the switch, and the second plurality of battery cells are connected in series with a load. In one example, the first plurality of battery cells, the second plurality of battery cells, and the switch are within an enclosure, the enclosure being within a pressure-regulated section of the aircraft. The load may be external to the enclosure. The battery assembly further includes a controller configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells in response to air pressure proximal to the first and second plurality of battery cells falling below a threshold level.

Description

[Technical Field]

[0001]

[0001] The present disclosure relates generally to battery technology, and more particularly to protecting battery packs. [Background technology]

[0002] Batteries are a common source of electrical power, for example, supplying direct current (DC) to a load. A battery has a positive terminal, or cathode, and a negative terminal, or anode. Multiple batteries can be combined in series and / or parallel to form a high-voltage and / or high-power DC power source.

[0003]

[0003] Rechargeable batteries can be charged and discharged, and such charge and discharge cycles can occur many times over the life of the battery. For example, when a battery is discharged during use, it can be recharged using an applied current, during which the original composition of the battery electrodes can be fully or at least partially restored by a reverse current. Examples of such rechargeable batteries include lead-acid batteries and lithium-ion batteries.

[0004] Batteries may be used in any number of applications, such as in consumer electronics devices, wearable devices, computers, electric and non-electric vehicles, and / or many other devices or systems that use DC power. Several significant challenges remain with regard to operating battery packs. [Brief explanation of the drawings]

[0005] [Figure 1]

[0005] FIG. 1 illustrates a battery assembly according to one embodiment of the present disclosure, comprising a plurality of battery cells within a housing, wherein the plurality of battery cells are arranged in series, the plurality of battery cells including one or more first battery cells and one or more second battery cells, and the battery assembly comprises a switch between the first one or more battery cells and the second one or more battery cells, the switch being turned off in response to the air pressure within the housing falling below a threshold pressure value. [Figure 2]

[0006] FIG. 2 illustrates the battery assembly of FIG. 1 installed in an aircraft, according to one embodiment of the disclosure. [Figure 3]

[0007] FIG. 3 illustrates a decompression event in an aircraft, for example, when the aircraft is at a first altitude H1, according to one embodiment of the present disclosure. [Figure 4]

[0008] FIG. 4 illustrates a decompression event in an aircraft, for example, when the aircraft is at a second altitude H2 that is higher than the first altitude H1 of FIG. 3, according to one embodiment of the present disclosure. [Figure 5A]

[0009] FIG. 5A illustrates a fault scenario that occurs when a switch between the first one or more battery cells and the second one or more battery cells of FIG. 1 is closed, the battery cells are disconnected from a load external to the enclosure, and the air pressure within the enclosure falls below a threshold air pressure, according to one embodiment of the present disclosure. [Figure 5B] FIG. 5B illustrates a fault scenario that occurs when a switch between the first one or more battery cells and the second one or more battery cells of FIG. 1 is closed, the battery cells are disconnected from a load external to the enclosure, and the air pressure within the enclosure falls below a threshold air pressure, according to one embodiment of the present disclosure. [Figure 6A]

[0010] FIG. 6A illustrates a fault scenario that occurs when a switch between the first one or more battery cells and the second one or more battery cells of FIG. 1 is open, the battery cells are disconnected from a load external to the enclosure, and the air pressure within the enclosure falls below a threshold air pressure, according to one embodiment of the present disclosure. [Figure 6B] FIG. 6B illustrates a fault scenario that occurs when a switch between the first one or more battery cells and the second one or more battery cells of FIG. 1 is open, the battery cells are disconnected from a load external to the enclosure, and the air pressure within the enclosure falls below a threshold air pressure, according to one embodiment of the present disclosure. [Figure 7]

[0011] FIG. 7 illustrates a battery assembly at least partially similar to the battery assembly of FIG. 1 , according to one embodiment of the present disclosure, wherein a switch between a first one or more battery cells and a second one or more battery cells is controlled by a controller within the housing and / or by a system external to the housing, and wherein controlling the switch is based at least in part on a sensor within the housing and / or a sensor external to the housing. [Figure 8]

[0012] FIG. 8 illustrates a battery assembly comprising a plurality of battery cells within a housing, the plurality of battery cells being arranged in series, the plurality of battery cells including: (i) one or more first battery cells; (ii) one or more second battery cells; (iii) one or more third battery cells; and (iv) one or more fourth battery cells, the battery assembly further comprising: (A) a first switch between the first one or more battery cells and the second one or more battery cells; (B) a second switch between the second one or more battery cells and the third one or more battery cells; and (C) a third switch between the third one or more battery cells and the fourth one or more battery cells, wherein the first switch, the second switch, and the third switch are turned off in response to the air pressure within the housing falling below a threshold pressure. [Figure 9]

[0013] FIG. 9 illustrates a flowchart illustrating a method for operating any of the battery assemblies described herein, according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006]

[0014] The drawings depict various embodiments of the present disclosure for purposes of illustration only and are not necessarily drawn to scale. Numerous variations, configurations and other embodiments will become apparent from the detailed description that follows.

[0007]

[0015] Techniques and structures for forming battery assemblies are disclosed. The battery assemblies may be used in any number of applications, but are particularly useful when installed on aircraft or other applications prone to arcing or shorting between terminals of battery cells of such battery assemblies and a housing that holds the battery cells due to a decompression event (e.g., when an aircraft including the battery assembly is flying above a threshold altitude). In some embodiments, the battery assembly includes a housing, first one or more battery cells and second one or more battery cells within the housing, and an intermediate switch between the first one or more battery cells and the second one or more battery cells. The first end switch is between the first one or more battery cells and a load external to the housing, and the second end switch is between the second one or more battery cells and the load. In one example, the first end switch, the first one or more battery cells, the intermediate switch, the second one or more battery cells, and the second end switch are connected in series with the load. In one example, the housing is within a section of an aircraft or other platform where air pressure is regulated.

[0008]

[0016] The battery assembly includes one or more sensors, which may be internal and / or external to the housing. For example, the sensor may detect air pressure within the housing (or may detect air pressure outside the housing but within a pressure-regulated section of the aircraft or platform) and output a sensed signal. In one example, the sensed signal indicates air pressure proximate to the battery cells (e.g., air pressure inside the housing or outside the housing). Continuing with the exemplary host platform of an aircraft, atmospheric pressure generally decreases with increasing altitude relative to standard atmospheric pressure at sea level. In one example, in addition to or instead of providing an indication of air pressure, the sensed signal may also provide an indication of the altitude of the battery assembly. Thus, the sensor (e.g., with attached sensor circuitry) may convert or correlate the detected air pressure to a corresponding altitude to provide an indication of the altitude of the battery assembly. During a decompression event, if the air pressure within or adjacent to the housing falls below a threshold pressure, this is indicated by the sensor's sensed signal. In one embodiment, a controller receives the sensed signal. In response to a sensing signal indicating that the air pressure has dropped below a threshold air pressure and / or that the altitude is above a threshold altitude, the controller opens one or more of the first end switch, the second end switch, and the middle switch. As described below, opening the one or more switches eliminates or reduces the possibility of arcing or shorting between the battery terminals and the housing, for example, during a pressure drop event. Numerous variations and embodiments will become apparent in light of this disclosure.

[0009] [General Overview]

[0017] Several significant issues remain regarding operating battery packs, such as those used on aircraft or other platforms susceptible to pressure changes. In one example, a battery pack including multiple battery cells is coupled in series with a load, where the multiple battery cells are within an enclosure installed within the aircraft. A minimum clearance "w1" is maintained between the battery cell terminals and a conductive wall of the enclosure (or between the battery cell terminals and a conductive element coupled to the enclosure). In one example, the clearance w1 may be sufficient to prevent or reduce the possibility of electrical arcing and short circuits between the battery cell terminals and the enclosure, for example, when the air pressure within the enclosure is maintained at sea level or an air pressure found at a relatively low altitude. In one example, the enclosure is within a section of the aircraft that has a regulated air pressure (e.g., a pressurization system maintains a minimum air pressure within the section of the aircraft). In one example, when the aircraft climbs at a high altitude, there is a drop in atmospheric pressure outside the aircraft based on the aircraft's altitude. However, the pressurization system regulates the air pressure to at least the minimum air pressure level within the aircraft. In one example, a decompression event could cause the pressurization system to fail, for example, due to a failure of the pressurization system and / or due to a crack or break in the body of the aircraft. If such a decompression event occurs at a high enough altitude, the air pressure inside the aircraft would drop rapidly (e.g., depending on the altitude and / or the severity of the decompression event). Exacerbating this situation is that air at lower pressures (e.g., at relatively higher altitudes) is a better conductor of electricity compared to air at sea level or relatively lower altitudes. Thus, if a decompression event occurs at a high enough altitude that the air pressure inside the enclosure drops sufficiently (e.g., below a threshold pressure level), this would increase the conductivity of the low-pressure air inside the enclosure, and the gap w1 between the battery terminals and the conductive wall of the enclosure may no longer be sufficient to prevent arcing or shorting between the battery terminals and the enclosure.

[0010]

[0018] Accordingly, techniques are described herein for forming a battery assembly for installation on an aircraft or other platform susceptible to pressure changes, wherein the possibility of arcing or shorting between the battery terminals and the housing of the battery assembly is eliminated or at least reduced, for example, during a depressurization event when the aircraft is flying at a high altitude (e.g., above a threshold altitude). For example, as described below, in response to air pressure within the housing of the battery assembly dropping below a threshold pressure, an intermediate switch between first one or more battery cells and second one or more battery cells is opened. Opening the intermediate switch (also referred to herein as an intermediate battery pack switch or contactor) and / or one or more other switches of the battery assembly eliminates or at least reduces the possibility of arcing or shorting between the battery terminals of the battery assembly and the housing.

[0011]

[0019] In some embodiments, a battery assembly includes a housing and a plurality of battery cells within the housing. In some examples, the battery cells may be lithium-ion battery cells, although other types of battery cells (such as lead-acid battery cells or hydrogen cells) may also benefit from the techniques described herein.

[0012]

[0020] In one example, the battery cells within the housing include a first one or more battery cells and a second one or more battery cells, and an intermediate switch between the first one or more battery cells and the second one or more battery cells. The first end switch is between the first one or more battery cells and a load external to the housing, and the second end switch is between the second one or more battery cells and the load. In one example, the first end switch, the first one or more battery cells, the intermediate switch, the second one or more battery cells, and the second end switch are connected in series with the load.

[0013]

[0021] The battery assembly includes one or more sensors, which may be internal and / or external to the housing. For example, the sensors may detect air pressure within the housing (or may detect air pressure within a pressure-regulated section of the platform, but outside the housing) and output a sensed signal. In one example, the sensed signal indicates air pressure proximate to the battery cells (e.g., air pressure inside or outside the housing) and / or altitude of the battery assembly. For example, the sensors (e.g., with attached sensor circuitry) may convert or correlate the detected air pressure to a corresponding altitude, providing an indication of the altitude of the battery assembly. Note that the detected air pressure and the detected altitude are generally correlated (lower air pressure corresponds to higher altitude, and higher air pressure corresponds to lower altitude).

[0014]

[0022] As described above, air pressure is regulated within a section of the platform that holds the battery assembly. For example, assume the platform is an aircraft, which may be manned or unmanned (e.g., an unmanned aerial vehicle or drone). In one such example, air pressure is maintained at a somewhat constant level, e.g., within a target pressure range. In one example, air pressure within the aircraft is maintained substantially at sea level pressure or an air pressure typically found at a particular altitude, e.g., the air pressure found at an altitude of 6,000 feet (ft), or 8,000 ft, or 10,000 ft. For example, air pressure at sea level may be approximately 101 kilopascals (kPa), and air pressure at an altitude of 8,000 ft may be approximately 75 kPa. In one example, the aircraft pressurization system is designed to maintain a minimum pressure typically found at an altitude of, e.g., approximately 75 kilopascals (kPa), although other pressure ranges may be possible and are implementation-specific.

[0015]

[0023] Thus, even if the aircraft is at an altitude above 8,000 ft, the aircraft pressurization system aims to regulate the air pressure within the aircraft to be approximately 75 kPa. Thus, even if the aircraft is flying at an altitude above 8,000 ft (e.g., 15,000 ft or 20,000 ft), the sensing signal described above will indicate a pressure of 75 kPa and / or an altitude of 8,000 ft, for example, because the interior sections and enclosures of the aircraft are pressurized to 75 kPa. Note that, in one example, if the aircraft is flying at an altitude below 8,000 ft, the air pressure within the aircraft may be higher than 75 kPa, for example, because the external air pressure at that altitude may be higher than 75 kPa.

[0016]

[0024] The battery assembly may not be safely operated at low air pressures, for example, when the air pressure inside the enclosure is less than a threshold air pressure due to the higher electrical conductivity of air at this low air pressure. This threshold air pressure may be based, for example, on the aforementioned gap w1 and / or the voltage level of the battery cells, and may be implementation-specific. As an example, assume the threshold air pressure is approximately 58 kPa, which is typically the air pressure at an altitude of approximately 15,000 ft. In this example, the altitude of 15,000 ft is the threshold altitude. Therefore, if the air pressure inside the aircraft (and inside the enclosure) falls below 58 kPa, the battery assembly may no longer be safe to operate.

[0017]

[0025] Now, if a decompression event occurs, the pressure regulation system can no longer effectively control the pressure inside the aircraft. In one example, the decompression event may occur at a sufficiently low altitude, such as below the threshold altitude (which in the example above is 15,000 ft). For example, assume that the decompression event occurs at an altitude of 12,000 ft, where the external air pressure is (for example) approximately 64 kPa. Due to the decompression event, the internal air pressure tends to equalize with the external air pressure. Thus, the interior of the aircraft, as well as the interior of the enclosure, is now at a pressure of approximately 64 kPa, which is still higher than the exemplary threshold pressure of 58 kPa. In one example, the sensed signal indicates an air pressure of 64 kPa. Additionally or alternatively, the sensed signal may also indicate a corresponding altitude of 12,000 ft (e.g., where this altitude may be derived from the sensed air pressure). Therefore, because the sensed air pressure is higher than the threshold air pressure and / or the sensed altitude is lower than the threshold altitude, the battery assembly remains operational, and the middle switch and the first and second end switches remain closed, for example, as also described below with respect to FIG. 3.

[0018]

[0026] In another example scenario, a decompression event may occur at a sufficiently high altitude, such as above a threshold altitude (15,000 ft in the example above). For example, assume that a decompression event occurs at an altitude of 20,000 ft, where the external air pressure is approximately 46 kPa. Thus, the interior of the aircraft, as well as the interior of the enclosure, is now at an air pressure of 46 kPa, which is lower than the example threshold pressure of 58 kPa above, and 20,000 ft is higher than the threshold altitude of 15,000 ft. In one example, the sensed signal indicates an air pressure of 46 kPa. Additionally or alternatively, the sensed signal may also indicate a corresponding altitude of 20,000 ft (e.g., where this altitude may be derived from the sensed air pressure). Thus, because the sensed air pressure is below the threshold air pressure and / or the sensed altitude is above the threshold altitude, the battery assembly may no longer be safely operated due to the gap w1 being insufficient at such low air pressure (as discussed above, low-pressure air has better electrical conductivity) to prevent arcing or shorting between the battery terminals of the battery assembly and the housing. In one embodiment, a controller (which may be internal to the housing or may be replaced by a control system external to the housing) receives the sensing signal indicating that the sensed air pressure is below the threshold air pressure and / or the sensed altitude is above the threshold altitude and issues a control signal to open one or more of the switches. For example, the first end switch and the second end switch may be opened by the controller, thereby disconnecting the battery cells from the load. In some such cases, even though the first one or more battery cells and the second one or more battery cells are no longer connected to the load (e.g., disconnected by opening two end switches), the series connection of the first one or more battery cells and the second one or more battery cells may still have sufficient electrical potential to cause arcing or an electrical short between the battery terminals and the housing, for example, due to (i) a small gap w1 between the battery terminals and the housing, and (ii) a low atmospheric pressure with a relatively high electrical conductivity. Thus, in one embodiment, in addition to opening the first and second end switches, the middle switch is also opened during the example decompression event described above.

[0019]

[0027] Opening the intermediate switch splits the series-connected battery cells into two separate, disconnected, disjoint groups of battery cells, e.g., a first one or more battery cells and a second one or more battery cells. This reduces the voltage of the battery cells in each such group, thereby eliminating or reducing the possibility of the above-mentioned arcing or short circuit between the battery terminals and the housing. Furthermore, if an arcing or electrical short occurs between the battery cells and the housing, such arcing or electrical short may be less severe (e.g., compared to a situation where the intermediate switch is not open) due to the lower voltage available to each group of battery cells.

[0020]

[0028] According to some embodiments of the present disclosure, these various approaches may be used individually or together to eliminate or reduce the possibility of arcing or short circuits between the battery terminals and the housing. Numerous variations and embodiments will become apparent in light of the present disclosure.

[0021]

[0029] As used herein, the term "about" indicates that the recited value may be varied slightly or otherwise within acceptable tolerances, provided that the variation does not result in process or device incompatibility. For example, for some elements, the term "about" may refer to a variation of ±0.1%, while for other elements, the term "about" may refer to a variation of ±1% or ±10%, or any point therein. Also, as used herein, terms defined in the singular are intended to include terms defined in the plural, and vice versa.

[0022]

[0030] Reference herein to any range of values ​​expressly includes each and every value (including fractions and integers) subsumed within that range. For example, reference herein to a range of "at least 50" or "at least about 50" includes every whole number equal to or greater than 50, and reference herein to a range of "less than 50" or "less than about 50" includes every whole number equal to or less than 49.

[0023]

[0031] As used herein, the terms "substantially" or "substantial" are equally applicable when used in the negative sense to refer to the complete or nearly complete absence of an action, feature, characteristic, state, structure, item, or result. For example, a surface that is "substantially" flat is either completely flat or so nearly flat that the effect would be the same as if the surface were completely flat.

[0024] [architecture]

[0032] FIG. 1 illustrates a battery assembly 100 comprising a plurality of battery cells 102 a, ..., 102 p in a housing 101 according to one embodiment of the present disclosure, wherein the plurality of battery cells 102 a, ..., 102 p are arranged in series, the plurality of battery cells 102 a, ..., 102 p including a first one or more battery cells 102 a, ..., 102 h and a second one or more battery cells 102 i, ..., 102 p, the battery assembly 100 comprising a switch 116 between the first one or more battery cells 102 a, ..., 102 h and the second one or more battery cells 102 i, ..., 102 p, the switch 116 being turned off in response to the air pressure in the housing 101 falling below a threshold pressure value.

[0025]

[0033] In some examples, the walls of the housing 101 comprise a metal, while in some other examples, the walls of the housing 101 comprise a non-metal. In one example, the walls of the housing 101 comprise a combination of a metal and a non-metal. In one example, the housing 101 is somewhat airtight but may have vents or openings, for example, to allow the housing 101 and battery cells 102a,..., 102p to "breathe" or, for example, to gradually exchange air or gas with the ambient (e.g., the space outside the housing 101). Thus, for example, a decrease in air pressure outside the housing 101 may result in a corresponding decrease in air pressure inside the housing 101, albeit after some time delay.

[0026]

[0034] In one embodiment, the individual battery cells 102 may comprise any suitable type of battery cell. For example, the individual battery cells 102 may comprise lithium-ion battery cells, although the battery cells 102 may be of another suitable type, such as lead-acid battery cells or hydrogen cells. In one example, the battery cells 102 a, ..., 102 n may be of any suitable size and may have any suitable shape or form factor. In one embodiment, each battery cell 102 includes an electrolyte in a corresponding container, although the electrolyte and containers of the battery cells 102 are not illustrated in FIG. 1 .

[0027]

[0035] In one embodiment, the switch 116 is between the first one or more battery cells 102a, ..., 102h and the second one or more battery cells 102i, ..., 102p. Thus, the switch 116, the first one or more battery cells 102a, ..., 102h, and the second one or more battery cells 102i, ..., 102p are in series.

[0028]

[0036] 1, there are 16 battery cells 102a,...,102p, with eight battery cells 102a,...,102h on one side of the switch 116 and eight other battery cells 102i,...,102p on the other side of the switch 116. Thus, in the example of FIG. 1, there are an equal number of battery cells on either side of the switch 116. In one example, the switch 116 is positioned in the middle of the series-connected battery cells, such that there are an equal number of battery cells on each side of the switch 116. In another example, the switch 116 is positioned approximately in the middle of the series-connected battery cells, such that the number of battery cells on each side of the switch 116 differs by at most one, or at most two, or at most three. For example, there may be an unequal number of battery cells on either side of the switch 116. In an example where there are 16 total battery cells, there may be 7 battery cells on one side of the switch 116 and 9 cells on the other side of the switch 116, or there may be 10 battery cells on one side of the switch 116 and 6 cells on the other side of the switch 116, and so on.

[0029]

[0037] The series-connected battery cells 102a, ..., 102p (e.g., connected through switch 116) are coupled to a load 140, for example, through load terminals (also called connectors) 138 and 139 of the housing 101. In one example, the load 140 is external to the housing 101. The load 140 may be any suitable load that can be driven by the battery cells 102a, ..., 102p.

[0030]

[0038] In one embodiment, the positive ends of the battery cells 102a, ..., 102p are coupled to the load 140 through the switch 112a and the load terminal 138 of the housing 101, and the negative ends of the battery cells 102a, ..., 102p are coupled to the load 140 through the switch 112b and the load terminal 139 of the housing 101. Thus, the switch 112a, the first one or more battery cells 102a, ..., 102h, the switch 116, the second one or more battery cells 102i, ..., 102p, and the switch 112b are in series, and the series-connected battery cells and the switch are connected to the load 140.

[0031]

[0039] In one embodiment, the controller 108 controls the switches 112a, 112b, and 116 using control signals 120a, 120b, and 124, respectively. For example, the controller 108 may use the control signal 120a to control the state of the switch 112a (e.g., open or close the switch 112a). Similarly, the controller 108 may use the control signal 120b to control the state of the switch 112b (e.g., open or close the switch 112b). Similarly, the controller 108 may use the control signal 124 to control the state of the switch 116 (e.g., open or close the switch 112b). The control signals 120a, 120b, and 124 are illustrated using dotted lines, for example, to better distinguish the control signals from the connections of the battery cells 102.

[0032]

[0040] In one example, the controller 108 is implemented using a processor, such as a microcontroller. While not illustrated, in one example, the processor may be coupled to a communications chip, for example, for communicating with the sensor 104 and / or the switches 112a, 112b, 116. In one embodiment, the processor is coupled to a computer-readable storage medium (not illustrated in FIG. 1 ), such as a memory or data storage device, also within the housing 101. In one embodiment, the computer-readable storage medium stores instructions or code that, when executed by the processor 108, cause the processor 108 to perform operations to control the switches 112a, 112b, and / or 116. In one embodiment, the processor 108 and / or memory are on a printed circuit board (PCB), where the PCB is mounted within the housing 101. In another example, the controller 108 is implemented using another suitable hardware circuit.

[0033]

[0041] In some embodiments, battery assembly 100 includes sensor 104, which in one example may be an air pressure sensor (such as a barometric pressure sensor). In some such embodiments, sensor 104 is within housing 101, while in some other embodiments, sensor 104 may be external to housing 101 (see, e.g., sensor 704 in FIG. 7). Sensor 104 monitors the air pressure within housing 101. A sensed signal 105 generated by sensor 104 is received by controller 108.

[0034]

[0042] As explained below, atmospheric pressure decreases with increasing altitude. For example, atmospheric pressure at 10,000 ft is lower than atmospheric pressure at sea level. In one example, in addition to or instead of providing an indication of barometric pressure, sensor 104 (and / or sensor circuitry coupled to sensor 104) may also provide the altitude of the battery assembly. Thus, the sensor circuitry may convert or correlate the detected barometric pressure to a corresponding altitude and provide an indication of the altitude of the battery assembly.

[0035]

[0043] 1 , one or more battery terminals (e.g., positive and / or negative terminals) of one or more battery cells 102 have a clearance of approximately “w1” from the housing 101. Thus, the battery terminals are separated from an interior wall of the housing 101 (or another conductive surface attached to the housing 101) by a clearance distance w1. In one example, the distance w1 may be the average distance between the battery terminals and the housing 101. In another example, the distance w1 may be the minimum or lowest distance between one or more battery terminals and the housing 101.

[0036]

[0044] In one example, the gap distance w1 may be sufficient to avoid arcing or unintentional electrical shorting between the battery terminals and the housing 101, for example, during "normal operating conditions" of the battery assembly 100, where "normal operating conditions" of the battery assembly 100 means operating the battery assembly 100 at or above a threshold atmospheric pressure value.

[0037]

[0045] For example, air typically exists between the battery terminals and the housing 101. At sea level pressure or at pressures present at altitudes below a threshold altitude (e.g., 15,000 ft), the distance w1 may be sufficient to avoid arcing or unintentional electrical shorting between the battery terminals and the housing 101. Thus, for example, the battery assembly 100 including the gap w1 may be designed and rated for sea level pressure or at pressures present at relatively low altitudes, such as below a threshold altitude.

[0038]

[0046] However, as and when the air pressure decreases (e.g., with increasing altitude or due to an aircraft decompression event), the conductivity of the air increases. Thus, at low air pressure (e.g., below a threshold air pressure level), the air between the battery terminals and the enclosure 101 has a higher conductivity (e.g., compared to the conductivity of air at pressures above the threshold air pressure level). Thus, as the air pressure within the enclosure 101 decreases, the likelihood of arcing or an unintentional electrical short between the battery terminals and the enclosure 101 increases.

[0039]

[0047] Thus, in one embodiment, controller 108 controls the state of switch 116 (and optionally also the state of switches 112a, 112b) based at least in part on sense signal 105 generated by sensor 104 and indicative of the air pressure within housing 101 and / or the altitude of housing 101 (where altitude may be estimated by measuring air pressure), e.g., as described herein. For example, when air pressure falls below a threshold air pressure level (or altitude exceeds a threshold altitude) as described above, switches 112a, 112b, and / or 116 are opened by controller 108 to, for example, eliminate or reduce the possibility of arcing or unintentional electrical shorts between the battery terminals and housing 101.

[0040]

[0048] 2 illustrates a battery assembly 100 installed in an aircraft 200, according to one embodiment of the present disclosure. In one example, the battery assembly 100 may be installed in any suitable type of aircraft, such as an airplane or helicopter, an unmanned aerial vehicle (UAV), a missile system, a spacecraft, or another powered aerial vehicle.

[0041]

[0049] For example, battery assembly 100 is located in an area of ​​aircraft 200 where air pressure (and possibly temperature) is regulated. For example, as aircraft 200 gains altitude, and as altitude increases, the air pressure outside the aircraft decreases. Thus, without pressure regulation, the air pressure inside the aircraft would correspondingly decrease, causing, for example, discomfort to passengers and / or causing detrimental problems to one or more elements within the pressure-regulated section of the aircraft.

[0042]

[0050] Thus, in some examples, air pressure is regulated within at least some sections of aircraft 200 such that air pressure is maintained at a somewhat constant level, e.g., within a target pressure range, within such sections of aircraft 200. In one example, air pressure within such sections of aircraft 200 is maintained substantially at an air pressure typically found at a particular altitude or range of altitudes, such as 6,000 feet (ft), or 8,000 ft, or 10,000 ft, or another suitable altitude or range of altitudes (or may even be maintained at sea level air pressure).

[0043]

[0051] As an example, air pressure at sea level may be approximately 101 kilopascals (kPa), and air pressure at an altitude of 8,000 ft may be approximately 75 kPa (note that the actual pressure and altitude values ​​presented herein are merely examples). The pressurization system of aircraft 200 may be designed to maintain a pressure typically found at an altitude of (for example) approximately 8,000 ft, e.g., approximately 75 kPa. Thus, even if the aircraft's altitude is above 8,000 ft, the pressurization system of aircraft 200 aims to regulate the air pressure within the aircraft to be approximately 75 kPa. In one example, there may be some fluctuation in air pressure within the pressurized section (e.g., varying between 101 and 70 kPa), but if successfully regulated, the air pressure within the regulated section, by way of example only, may not fall below 75 kPa or 70 kPa.

[0044]

[0052] By way of example, and without limiting the scope of the present disclosure, it is assumed that the air pressure within aircraft 200 is maintained at 75 kPa, e.g., a pressure typically found at an altitude of approximately 8,000 ft. However, such values ​​are merely examples, and the air pressure may be adjusted to other suitable pressure levels.

[0045]

[0053] Thus, once the air pressure has been successfully adjusted within the aircraft 200, the sensor 104 will output an air pressure of approximately 75 kPa, even if the air pressure outside the aircraft is less than 75 kPa.

[0046]

[0054] In one example, in addition to or instead of providing an indication of pressure, sensor 104 (and / or sensor circuitry coupled to sensor 104) may also provide an altitude of battery assembly 100. For example, sensor circuitry may convert or correlate the air pressure detected within enclosure 101 to a corresponding altitude and provide an indication of the altitude of the battery assembly. Thus, sensor 104 may provide an altitude of 8,000 ft even if aircraft 200 is flying at a much higher altitude, such as an altitude of 15,000 ft or 20,000 ft.

[0047]

[0055] By way of example, and without limiting the scope of the present disclosure, the threshold air pressure for activating switches 116, 112a, and / or 112b may be assumed to be approximately 58 kPa, e.g., the air pressure typically found at 15,000 ft (which may be the threshold altitude value). Thus, if the pressure sensed by sensor 104 is less than 58 kPa and / or the altitude sensed by sensor 104 is greater than 15,000 ft, controller 108 activates (e.g., opens) switches 116, 112a, and / or 112b as described herein.

[0048]

[0056] In one example, the threshold air pressure and threshold altitude may be implementation-specific and may depend on various factors, such as the gap distance w1, the actual voltage supplied by the battery cell 102, and / or one or more other related factors.

[0049]

[0057] Figure 3 illustrates a decompression event in aircraft 200 of Figure 2 when, for example, aircraft 200 is at a first altitude H1, according to one embodiment of the disclosure. Figure 4 illustrates a decompression event in aircraft 200 of Figure 2 when, for example, aircraft 200 is at a second altitude H2 that is higher than first altitude H1 of Figure 3, according to one embodiment of the disclosure.

[0050]

[0058] 3 , aircraft 200 is at a first altitude or height H1 above sea level 350 and a decompression event occurs. A decompression event is an unintentional event when a pressurized section of aircraft 200 (e.g., a section of aircraft 200 where pressure is regulated) loses air pressure. The decompression event may be due to, for example, a failure of a mechanism used to regulate air pressure within aircraft 200. In another example, the decompression event may be due to a relatively large opening 304 that may have unintentionally formed in the fuselage of aircraft 200 (e.g., due to an accident or a crack in the fuselage of the aircraft).

[0051]

[0059] In any such case where a decompression event occurs, the air pressure within aircraft 200 can no longer be effectively regulated. Based on the severity of the decompression event, the air pressure within aircraft 200 tends to approach the air pressure outside aircraft 200. Also, as the altitude of aircraft 200 increases, the air pressure outside aircraft 200 decreases. Thus, the air pressure outside aircraft 200 at altitude H1 may be lower than the air pressure at sea level.

[0052]

[0060] In instances where the decompression event is relatively minor (e.g., a partially functioning pressure regulating mechanism or a small crack in the aircraft fuselage), the air pressure within aircraft 200 may be adjusted to some extent. However, in instances where the decompression event is relatively major (e.g., a non-functioning pressure regulating mechanism or a large crack in the aircraft fuselage), the air pressure within aircraft 200 may not be adjusted at all.

[0053]

[0061] Thus, depending on altitude H1 (and the corresponding air pressure outside aircraft 200 at altitude H1) and / or the severity of the decompression event, the air pressure inside aircraft 200 decreases. As the air pressure inside aircraft 200 decreases, there is a corresponding decrease in air pressure inside enclosure 101. Sensor 104 senses the air pressure inside enclosure 101 and indicates the air pressure inside enclosure 101 via sensed signal 105.

[0054]

[0062] It should be noted that if the aircraft 200 is at a lower altitude (e.g., in the example above where the air pressure inside the aircraft is adjusted to 75 kPa, which may be found at 8,000 ft, altitude H1 is less than 8,000 ft), there may be no decompression or drop in pressure inside the aircraft 200.

[0055]

[0063] 3 , the air pressure inside the aircraft 200, and therefore the air pressure inside the enclosure 101, may still be higher than the threshold air pressure mentioned above (e.g., in the example described herein above, 58 kPa, or the pressure found at an altitude of 15,000 ft). Thus, at altitude H1, it may still be safe to operate the battery assembly (e.g., the possibility of arcing or an unintended electrical short between the battery terminals and the enclosure 101 may still be within an acceptable range). For example, altitude H1 may be less than the threshold altitude of 15,000 ft, and therefore the air pressure inside the enclosure 101 may be higher than the threshold pressure of approximately 58 kPa. Thus, the sense signal 105 may indicate that the air pressure inside the enclosure 101 is higher than the threshold air pressure and / or that the altitude is lower than the threshold altitude. Thus, the switches 112a, 112b, 116 may remain closed, and the battery assembly may operate normally, e.g., continue to supply power to the load 140.

[0056]

[0064] 4, aircraft 200 is at a second altitude or height H2 above sea level 350 and a decompression event occurs within aircraft 200. Thus, similar to Figure 3, in the scenario of Figure 4, air pressure within aircraft 200 can no longer be effectively regulated.

[0057]

[0065] Depending on altitude H2 (and the corresponding air pressure outside aircraft 200 at altitude H2) and / or the severity of the decompression event, the air pressure inside aircraft 200 decreases. As the air pressure inside aircraft 200 decreases, there is a corresponding decrease in air pressure inside enclosure 101. Sensor 104 senses the air pressure inside enclosure 101 and indicates the air pressure inside enclosure 101 via sensed signal 105.

[0058]

[0066] Height H2 in example Figure 4 may be higher than height H1 in example Figure 3. In the example of Figure 4, the air pressure within aircraft 200, and therefore within enclosure 101, may also be lower than the threshold air pressure discussed above (e.g., in the example discussed herein above, 58 kPa, or the pressure found at an altitude of 15,000 ft). For example, altitude H2 may be greater than the threshold altitude of 15,000, and therefore the air pressure within enclosure 101 may fall below the threshold pressure of approximately 58 kPa due to a decompression event.

[0059]

[0067] Thus, it may no longer be safe to operate the battery assembly because the possibility of arcing or an unintentional electrical short between the battery terminals and the housing 101 may be outside of an acceptable range due to the low air pressure within the housing 101. For example, the sense signal 105 may indicate that the air pressure inside the housing 101 is below a threshold air pressure and / or the altitude is above a threshold altitude. Thus, one or more of the switches 112a, 112b, 116 may be opened by the controller 108, for example, using the control signals 120a, 120b, and / or 124, respectively. Thus, in the example of FIG. 4, the battery assembly stops supplying power to the load 140.

[0060]

[0068] 4 , opening switches 112a and / or 112b effectively decouples battery cells 102a...102p from load 140. Thus, switch 116 does not contribute to disconnecting battery cells 102a...102p from load 140. Rather, opening switch 116 reduces the total potential level provided by battery cells 102a...102p, for example, by breaking the series connection of battery cells 102a...102p into two separate series connections comprising a first battery cell 102a...102h and a second battery cell 102i...102p. In one embodiment, breaking the series connection of battery cells 102a...102p into two separate series connections reduces the possibility of high-voltage arcing within enclosure 101.

[0061]

[0069] 5A and 5B illustrate a fault scenario that occurs when the switch 116 between the first one or more battery cells 102a, ..., 102h and the second one or more battery cells 102i, ..., 102p of FIG. 1 is closed, when these battery cells 102a, ..., 102p are disconnected from the load 140 external to the enclosure 101, and when the air pressure inside the enclosure falls below the threshold air pressure described above, in accordance with one embodiment of the present disclosure.

[0062]

[0070] 4, the sensing signal 105 indicates that the air pressure within the enclosure 101 is below a threshold air pressure and / or the altitude is above a threshold altitude. Therefore, for safety reasons as discussed above, switches 112a and 112b are now open. However, because switch 116 is still closed, the electrical potential across the series-connected battery packs is available for potential arcing or shorting with the enclosure 101. Furthermore, due to the pressure reduction event and the resulting air pressure within the enclosure 101 being less than the threshold air pressure, the likelihood of such potential arcing or shorting with the enclosure 101 increases beyond an acceptable risk level.

[0063]

[0071] By way of example only, assume there are 16 battery cells 102a,...,102p, each having a voltage level of approximately 50 volts (V). Thus, in the example of Figures 5A and 5B, the series-connected battery cells 102a,...,102p have a combined potential of 16 x 50V, e.g., 800V, as symbolically labeled in Figure 5A.

[0064]

[0072] Furthermore, due to such a relatively high 800V potential level, and due to the air pressure within the enclosure 101 being less than the threshold air pressure, the possibility of arcing increases even further. For example, FIG. 5B illustrates an arcing event 504 between battery cell 102a and enclosure 101. Thus, there are 16 series-connected battery cells 102a,...,102p, and thus a potential level of 16 x 50V, or 800V, can be shorted to enclosure 101, thereby generating a relatively higher short-circuit current (e.g., higher compared to the scenario of FIG. 6B) and a resulting potential fire hazard.

[0065]

[0073] 6A and 6B illustrate a fault scenario that occurs when the switch 116 between the first one or more battery cells 102a, ..., 102h and the second one or more battery cells 102i, ..., 102p of FIG. 1 is open, and when these battery cells 102a, ..., 102p are disconnected from the load 140 external to the enclosure 101, and when the air pressure inside the enclosure falls below the threshold air pressure described above, in accordance with one embodiment of the present disclosure.

[0066]

[0074] 5A and 5B, switch 116 is closed, while in FIGS. 6A and 6B, switch 116 is open. By opening switch 116, the series of battery cells 102a, ..., 102p is now separated into two disconnected and disjoint series of battery cells, such as a first series including battery cells 102a, ..., 102h and a second series including battery cells 102i, ..., 102p. Thus, by opening switch 116, approximately half the potential of the battery pack is available for potential arcing or shorting with the housing 101. For example, assuming there are 16 battery cells 102a, ..., 102p, each having a voltage level of approximately 50V, each of the first and second series of battery cells described above has a maximum potential of 8 x 50V, e.g., 400V, as symbolically labeled in FIG. 6A. Furthermore, such a relatively low potential level of 400V (e.g., lower than 800V in FIGS. 5A and 5B) reduces the likelihood of arcing (e.g., lower than in the scenarios of FIGS. 5A and 5B). Furthermore, if arcing does occur, the severity of the arcing is also reduced (e.g., compared to the scenarios of FIGS. 5A and 5B).

[0067]

[0075] 6B illustrates an arcing event 604 between battery cell 102a and housing 101. However, there are only eight series-connected battery cells 102a,...,102p, and therefore a potential level of 400V can be shorted to housing 101, thereby generating a relatively lower short-circuit current (e.g., lower compared to the scenario of FIG. 5B).

[0068]

[0076] FIG. 7 illustrates a battery assembly 700 at least partially similar to the battery assembly of FIG. 1 , according to one embodiment of the present disclosure, wherein a switch 116 between a first one or more battery cells 102 a, ..., 102 h and a second one or more battery cells 102 i, ..., 102 p is controlled by a controller 108 within the housing 101 and / or by a system 708 external to the housing 101, and wherein controlling the switch 116 is based at least in part on a pressure sensor 104 within the housing 101 and / or a sensor 704 external to the housing 101.

[0069]

[0077] Thus, in one example, controlling switches 112a, 112b, 116 may be performed by processor 108 and / or by system 708. In one example, system 708 comprises a processor coupled to a computer-readable storage medium (not illustrated in FIG. 7 ), such as a memory or data storage device. In one embodiment, the computer-readable storage medium stores instructions or code that, when executed by processor 708, cause processor 708 to perform operations to control switches 112a, 112b, and / or 116. In one embodiment, processor 708 and / or memory are on a PCB that is external to housing 101. In one example, system 708 may issue control signals 120a, 120b, and / or 124, for example, through controller 108 or bypassing controller 108 (although FIG. 7 does not illustrate control signals 120a, 120b, and / or 124 issued by system 708 by bypassing controller 108). In one example, a human user may interact with system 708 to at least partially control the issuance of control signals 120a, 120b, and / or 124, for example, in the event of a depressurization of aircraft 200 and a resulting pressure drop below the aforementioned threshold pressure.

[0070]

[0078] 1, sensor 104 was inside housing 101. In contrast, in FIG. 7, sensor 104 is inside housing 101 and another similar (or different) sensor 704 is outside housing 101. In one example, a battery assembly may include either sensor 104 or 704, or both sensors 104 and 704.

[0071]

[0079] Controller 108 and / or system 708 receives sensed signal 105 from sensor 104 indicative of air pressure inside housing 101 and / or receives sensed signal 705 from sensor 704 indicative of air pressure outside housing 101. Based on sensed signal 105 and / or 705 indicating the air pressure is less than the above-mentioned threshold pressure, controller 108 and / or system 708 issues control signals 120a, 120b, and / or 124 to open switches 112a, 112b, and / or 116, respectively, as described herein above.

[0072]

[0080] It should be noted that in one example, in addition to or instead of indicating barometric pressure, sensors 104 and / or 704 may indicate the altitude of aircraft 200, as described herein and above, and controlling the switch may also be based at least in part on such altitude reading.

[0073]

[0081] FIG. 8 illustrates a battery assembly 800 comprising a plurality of battery cells 102 a, ..., 102 p in a housing 101 according to one embodiment of the present disclosure, wherein the plurality of battery cells 102 a, ..., 102 p are arranged in series, and the plurality of battery cells 102 a, ..., 102 p includes: (i) a first one or more battery cells 102 a, ..., 102 d; (ii) a second one or more battery cells 102 e, ..., 102 h; (iii) a third one or more battery cells 102 i, ..., 102 l; and (iv) a fourth one or more battery cells 102 m, ..., 102 p; and the battery assembly 100 includes: (A) a first one or more battery cells 102 a, ..., 102 d; (B) a second one or more battery cells 102 e, ..., 102 h; (C) a third one or more battery cells 102 i, ..., 102 l; and (D) a fourth one or more battery cells 102 m, ..., 102 p. , 102p, (A) a first switch 816a between the second one or more battery cells 102a, ..., 102d and the second one or more battery cells 102e, ..., 102h; (B) a second switch 116 between the second one or more battery cells 102e, ..., 102h and the third one or more battery cells 102i, ..., 102l; and (C) a third switch 816b between the third one or more battery cells 102i, ..., 102l and the fourth one or more battery cells 102m, ..., 102p, wherein the first switch 816a, the second switch 116, and the third switch 816b are turned off in response to the air pressure in the housing 101 falling below a threshold pressure.

[0074]

[0082] Thus, in the battery assembly 100 of FIG. 1, the battery cells 102a, ..., 102p are divided into two groups, and there is a switch 116 between the battery cells of these two groups to disconnect the battery cells 102a, ..., 102h of the first group from the battery cells 102i, ..., 102p of the second group, thereby resulting in a maximum voltage of 400V (in the example of FIG. 6A) in either the first or second group of battery cells (e.g., assuming 16 battery cells, each having a voltage of 50V).

[0075]

[0083] 8, the battery cells 102a...102p are divided into four groups, with switches 816a, 816b, 816c, 816d, and 816e between the battery cells of two corresponding groups, for example, to disconnect the battery cells of each group from the battery cells of adjacent groups. This results in a maximum voltage of 200V for any of the battery cells in the first, second, third, or fourth groups (e.g., assuming 16 battery cells, each having a voltage of 50V). This results in a lower voltage level for each battery group, for example, thereby further reducing the possibility of arcing or unintentional electrical shorting between the battery terminals and the housing 101, and / or the severity of any such arcing, compared to the case of a single switch, for example, when a single switch 116 is present in the battery assembly.

[0076]

[0084] In another example, it will be appreciated that instead of one switch (e.g., switch 116 in FIG. 1 ) or three switches (e.g., switches 816a, 816b, 116 in FIG. 8 ), the battery assembly may include another suitable number of switches (e.g., two, four, or more) in the string of battery cells to separate the battery cells into corresponding groups of disjointed and disconnected battery cells (e.g., when a switch is open).

[0077]

[0085] 8, switches 816a, 816b may, in one example, be controlled by the above-described control signal 124. The operation of switches 816a, 816b may, in one example, be similar to the above-described operation of switch 116.

[0078]

[0086] 9 illustrates a flowchart illustrating a method 900 for operating any of the battery assemblies described herein, according to one embodiment of the disclosure. At 904 of the method 900, power is supplied from the first plurality of battery cells 102a, ..., 102h and the second plurality of battery cells 102i, ..., 102p to the load 140 (see, e.g., FIG. 1). A first switch 116 is between the first plurality of battery cells 102a, ..., 102h and the second plurality of battery cells 102i, ..., 102p. A second switch 112a is between the first plurality of battery cells 102a, ..., 102h and the load 140. A third switch 112b is between the second plurality of battery cells 102i, ..., 102p and the load 140, as described above. Additional switches, such as switches 816a and 816b, may be present (see FIG. 8).

[0079]

[0087] Method 900 proceeds from 904 to 908, where one or more sensed signals (e.g., sensed signals 105 and / or 705) output by corresponding one or more sensors (e.g., sensors 104 and / or 704) are monitored. In one example, the one or more sensed signals indicate air pressure proximate the battery assembly and / or the altitude of the battery assembly. The air pressure proximate the battery assembly is the air pressure within housing 101 (e.g., measured by sensor 104) and / or the air pressure outside housing 101 but within a pressurized section of aircraft 200 (e.g., measured by sensor 704).

[0080]

[0088] Because the air pressure is regulated within a pressurized section of aircraft 200 in which the battery assembly is installed, the air pressure will be as regulated by the aircraft's pressurization system. For example, when the pressurization system is operable as intended, the air pressure will be at least near a target air pressure, such as 75 kPa, which is the air pressure typically found at an altitude of 8,000 ft. In such an example, the battery assembly's altitude reading will be 8,000 ft even when aircraft 200 is flying at a much higher altitude.

[0081]

[0089] However, if aircraft 200 experiences a depressurization event at a higher altitude (e.g., greater than 8,000 ft for the example scenario described above), the pressure in the pressurized sections of aircraft 200, as well as the pressure in the battery assemblies, will decrease. Accordingly, the altitude reading will also commensurate with the decreased air pressure level and indicate a corresponding higher altitude. In one example, if the air pressure falls below the threshold air pressure and / or the altitude reading exceeds the threshold altitude, switches 112a, 112b, and / or 116 must be opened.

[0082]

[0090] The method 900 proceeds from 908 to 912, where the controller 108 and / or system 708 monitors, for example, based on the monitored sensed signals, whether the air pressure is less than a threshold pressure value and / or the altitude reading is greater than a threshold altitude value.

[0083]

[0091] A "No" at 912 indicates that a decompression event has not occurred. A "No" at 912 may also be possible if a decompression event occurred, but at a lower altitude and without a sufficient drop in air pressure. Thus, if "No" at 912, method 900 loops back to 908 to continue monitoring the sensed signal.

[0084]

[0092] If 912 returns "Yes," this indicates that a decompression event occurred at a high enough altitude that the air pressure within the enclosure 101 decreased to the point where it is no longer safe to operate the battery assembly. Accordingly, the method proceeds from 912 to 916. At 916, one or more (e.g., all) of the first switch 116, the second switch 112a, and the third switch 112b are opened (e.g., by the controller 108 and / or the system 708 using the respective control signals 124, 120a, 120b). This eliminates or reduces the possibility of electrical arcing within the battery assembly (as well as the severity of such arcing, if it occurs), thereby preventing fire hazards and / or other potential hazards that may arise from any such electrical arcing, as discussed above.

[0085]

[0093] It should be noted that the processes in method 900 are shown in a particular order for ease of explanation. However, according to some embodiments, one or more of the processes may be performed in a different order or may not be performed at all (and may therefore be optional). Numerous variations on method 900 and techniques described herein will be apparent in light of this disclosure.

[0086] Further Example Embodiments

[0094] The following examples relate to further embodiments, from which numerous permutations and configurations are apparent.

[0087]

[0095] Example 1. A battery assembly comprising: a first plurality of battery cells, a second plurality of battery cells, and a switch between the first and second plurality of battery cells such that the first plurality of battery cells, the switch, and the second plurality of battery cells are connected in series to a load; and a controller configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells in response to air pressure proximal to the first and second plurality of battery cells falling below a threshold level.

[0088]

[0096] Example 2. The battery assembly of Example 1, further comprising a sensor configured to monitor air pressure proximate the first and second plurality of battery cells and output a sensing signal, wherein the controller is configured to open a switch and disconnect the first plurality of battery cells from the second plurality of battery cells based at least in part on the sensing signal.

[0089]

[0097] Example 3. A battery assembly as described in any one of Examples 1-2, further comprising a sensor circuit for monitoring air pressure proximal to the first and second plurality of battery cells and outputting a sensing signal, the sensing signal indicating an altitude of the battery assembly, wherein the altitude of the battery assembly is based on air pressure proximal to the first and second plurality of battery cells, and wherein the controller is configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells based at least in part on the sensing signal indicating that the sensed altitude is higher than a threshold altitude.

[0090]

[0098] Example 4. The battery assembly of any one of Examples 1 to 3, wherein the switch is a first switch, and the battery assembly further includes: a second switch between the first plurality of battery cells and a first load terminal configured to be connected to a load; and a third switch between the second plurality of battery cells and a second load terminal configured to be connected to the load, such that the second switch, the first plurality of battery cells, the first switch, the second plurality of battery cells, and the third switch are configured to be connected in series between the first load terminal and the second load terminal.

[0091]

[0099] Example 5. The battery assembly of Example 4, wherein the controller is further configured to control the second and third switches based at least in part on air pressure proximate the first and second pluralities of battery cells.

[0092]

[0100] Example 6. The battery assembly of any one of Examples 1-5, further comprising a housing for holding the first and second plurality of battery cells, wherein the housing includes one or more load terminals configured to couple to a load.

[0093]

[0101] Example 7. The battery assembly of example 6, wherein the controller is within the housing.

[0094]

[0102] Example 8. A battery assembly according to any one of Examples 6 to 7, further comprising a sensor configured to monitor air pressure proximal to the first and second plurality of battery cells and output a sensing signal, wherein the sensor is within the housing.

[0095]

[0103] Example 9. The battery assembly of any one of Examples 6-8, wherein the air pressure proximal to the first and second pluralities of battery cells is the air pressure within the enclosure.

[0096]

[0104] Example 10. A method of operating a battery assembly, the method comprising: supplying power to a load from a first plurality of battery cells and a second plurality of battery cells, wherein a first switch is between the first plurality of battery cells and the second plurality of battery cells, a second switch is between the first plurality of battery cells and the load, and a third switch is between the second plurality of battery cells and the load; monitoring one or more sensed signals output by corresponding one or more sensors, the one or more sensed signals indicating air pressure proximate the battery assembly and / or an altitude of the battery assembly; and controlling the first, second, and third switches based at least in part on the one or more sensed signals.

[0097]

[0105] Example 11. The method of example 10, wherein controlling the first, second, and third switches comprises opening one or more of the first, second, and third switches in response to the air pressure being less than a threshold pressure value and / or the altitude being greater than a threshold altitude value.

[0098]

[0106] Example 12. The method of any one of Examples 10-11, further comprising: installing a battery assembly within the aircraft; and, in response to a decompression event within the aircraft when the aircraft is at or above a threshold altitude, one or more sensing signals output by corresponding one or more sensors indicating that the air pressure is less than a threshold pressure value and / or the altitude is greater than a threshold altitude value; and opening one or more of the first, second, and third switches based on the one or more sensing signals indicating that the air pressure is less than the threshold pressure value and / or the altitude is greater than the threshold altitude value.

[0099]

[0107] Example 13. The method of any one of Examples 10-12, further comprising: installing a battery assembly within the section of the aircraft; and adjusting the air pressure within the section of the aircraft.

[0100]

[0108] Example 14. The method of any one of Examples 10-12, wherein the first number of battery cells in the first plurality of battery cells and the second number of battery cells in the second plurality of battery cells are equal to or differ by at most two.

[0101]

[0109] Example 15. The method of any one of Examples 10 to 14, wherein the first plurality of battery cells and the second plurality of battery cells are in an enclosure, and the method further comprises installing an enclosure containing the first and second plurality of battery cells in an aircraft, and monitoring the one or more sensing signals comprises sensing air pressure in the enclosure by a pressure sensor among the one or more sensors, and monitoring the sensing signal output by the pressure sensor.

[0102]

[0110] Example 16. The method of any one of Examples 10 to 15, wherein the first plurality of battery cells and the second plurality of battery cells are in a housing, and the method further comprises installing a housing containing the first and second plurality of battery cells in an aircraft, and monitoring the one or more sensing signals comprises sensing the altitude of the housing based on the air pressure in the housing by a sensor of the one or more sensors, and monitoring the sensing signal output by the sensor.

[0103]

[0111] Example 17. A system comprising: an aircraft; a plurality of battery cells comprising a first one or more battery cells and a second one or more battery cells, the plurality of battery cells being within the aircraft, wherein the aircraft is fully or at least partially powered by the plurality of battery cells; a sensor configured to output a sensing signal indicative of air pressure proximate the plurality of battery cells; and a controller configured to disconnect the first one or more battery cells from the second one or more battery cells in response to the sensing signal indicating the air pressure is less than a threshold value.

[0104]

[0112] Example 18. The system of Example 17, further comprising a switch between the first one or more battery cells and the second one or more battery cells, wherein the controller is configured to issue a control signal that transitions the switch to an open state to disconnect the first one or more battery cells from the second one or more battery cells.

[0105]

[0113] Example 19. A system described in any one of Examples 17 to 18, further comprising a first switch and a second switch, and a first load terminal and a second load terminal, wherein a plurality of battery cells are coupled to the first and second load terminals through the first switch and the second switch, respectively, and wherein the controller is further configured to issue one or more control signals that transition the first and second switches to an open state in response to a sensing signal indicating that the air pressure is less than a threshold.

[0106]

[0114] Example 20. A system described in any one of Examples 17 to 19, further comprising a housing, wherein the plurality of battery cells and the sensor are within the housing, the housing is within an aircraft, and the sensing signal indicates air pressure within the housing.

[0107]

[0115] The foregoing description of example embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future applications claiming priority to this application may claim the disclosed subject matter differently and may generally include any set of one or more limitations as variously disclosed or otherwise set forth herein.

Claims

1. 1. A battery assembly comprising: a first plurality of battery cells, a second plurality of battery cells, and a switch between the first plurality of battery cells and the second plurality of battery cells, such that the first plurality of battery cells, the switch, and the second plurality of battery cells are connected in series to a load; a controller configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells in response to air pressure proximate the first and second plurality of battery cells falling below a threshold level; A battery assembly comprising:

2. a sensor configured to monitor the air pressure proximate the first and second plurality of battery cells and output a sensing signal; wherein the controller is configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells based at least in part on the sense signal. The battery assembly of claim 1 .

3. further comprising a sensor circuit for monitoring the air pressure proximate the first and second plurality of battery cells and outputting a sense signal, the sense signal indicating an altitude of the battery assembly, wherein the altitude of the battery assembly is based on the air pressure proximate the first and second plurality of battery cells; wherein the controller is configured to open the switch and disconnect the first plurality of battery cells from the second plurality of battery cells based at least in part on the sensing signal indicating that the sensed altitude is greater than a threshold altitude. The battery assembly of claim 1 .

4. The switch is a first switch, and the battery assembly is a second switch between the first plurality of battery cells and a first load terminal configured to be connected to the load; a third switch between the second plurality of battery cells and the second load terminal configured to be connected to the load, such that the second switch, the first plurality of battery cells, the first switch, the second plurality of battery cells, and the third switch are configured to be connected in series between the first load terminal and a second load terminal; The battery assembly of claim 1 further comprising:

5. 5. The battery assembly of claim 4, wherein the controller is further configured to control the second and third switches based at least in part on the air pressure proximate the first and second pluralities of battery cells.

6. 10. The battery assembly of claim 1, further comprising a housing for holding the first and second pluralities of battery cells, wherein the housing includes one or more load terminals configured to couple to the load.

7. The battery assembly of claim 6 , wherein the controller is within the housing.

8. a sensor configured to monitor the air pressure proximate the first and second plurality of battery cells and output a sensing signal; wherein the sensor is located within the housing.

7. The battery assembly of claim 6.

9. The battery assembly of claim 6 , wherein the air pressure proximate the first and second pluralities of battery cells is the air pressure within the enclosure.

10. 1. A method of operating a battery assembly, the method comprising: supplying power from a first plurality of battery cells and a second plurality of battery cells to a load, wherein a first switch is between the first plurality of battery cells and the second plurality of battery cells, a second switch is between the first plurality of battery cells and the load, and a third switch is between the second plurality of battery cells and the load; monitoring one or more sensed signals output by one or more corresponding sensors, the one or more sensed signals indicative of an air pressure proximate the battery assembly and / or an altitude of the battery assembly; controlling the first, second, and third switches based at least in part on the one or more sense signals; A method comprising:

11. Controlling the first, second, and third switches includes:

11. The method of claim 10, comprising opening one or more of the first, second, and third switches in response to the air pressure being less than a threshold pressure value and / or the altitude being greater than a threshold altitude value.

12. the battery assembly is located on board an aircraft; the one or more sensors are configured to output the one or more sensed signals indicative of a pressure event when the air pressure is outside a predetermined range and / or when the altitude is outside a predetermined range; one or more of the first, second, and third switches are controllable based on the one or more sensed signals indicating that the air pressure is outside the predetermined pressure range and / or that the altitude is outside the predetermined altitude range; The method of claim 10.

13. The battery assembly is installed in a section of an aircraft, and the method comprises: adjusting the air pressure within the section of the aircraft; The method of claim 10 further comprising:

14. 11. The method of claim 10, wherein a first number of battery cells in the first plurality of battery cells and a second number of battery cells in the second plurality of battery cells are equal or differ by at most two.

15. The first plurality of battery cells and the second plurality of battery cells are in an enclosure within the aircraft, and monitoring the one or more sensed signals includes: sensing the air pressure within the enclosure with a pressure sensor among the one or more sensors; monitoring a sensed signal output by the pressure sensor; The method of claim 10, comprising:

16. The first plurality of battery cells and the second plurality of battery cells are in an enclosure within the aircraft, and monitoring the one or more sensed signals includes: sensing, with a sensor of the one or more sensors, an altitude of the enclosure based on the air pressure within the enclosure; monitoring a sensed signal output by the sensor; The method of claim 10, comprising:

17. 1. A system comprising: Aircraft and a plurality of battery cells, including first one or more battery cells and second one or more battery cells, the plurality of battery cells being within the aircraft, and wherein the aircraft is fully or at least partially powered by the plurality of battery cells; a sensor configured to output a sensed signal indicative of air pressure proximate the plurality of battery cells; a controller configured to disconnect the first one or more battery cells from the second one or more battery cells in response to the sense signal indicating the air pressure is less than a threshold; A system comprising:

18. further comprising a switch between the first one or more battery cells and the second one or more battery cells; wherein the controller is configured to issue a control signal that transitions the switch to an open state to disconnect the first one or more battery cells from the second one or more battery cells.

20. The system of claim 17.

19. a first switch and a second switch; a first load terminal and a second load terminal, wherein the plurality of battery cells are coupled to the first and second load terminals through the first switch and the second switch, respectively; Furthermore, wherein the controller is further configured to issue one or more control signals to transition the first and second switches to an open state in response to the sensing signal indicating that the air pressure is less than the threshold.

20. The system of claim 17.

20. 20. The system of claim 17, further comprising an enclosure, wherein the plurality of battery cells and the sensor are within the enclosure, the enclosure is within the aircraft, and the sensed signal is indicative of the air pressure within the enclosure.

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