Method and system for battery monitoring circuit

Abstract

A method and system for determining the health of a set of batteries by using a battery monitoring circuit. The battery monitoring circuit includes a first current loop and a second current loop. The first current loop is enabled by the first switch, the first resistor, and the second switch. The second current loop is enabled by the first switch, the third switch, the voltage sensor, and the second switch.

Description

Government funded research

[0001] The project leading to this application has received funding from NASA under the NASA EPFD program and under Grant Agreement No. 80AFRC-21-C-A021. Technical Field

[0002] The present disclosure relates generally to battery monitoring circuits, and more particularly to battery monitoring circuits for determining the health of a group of batteries. Background Art

[0003] Batteries are used as an energy source to feed DC electrical loads. During the life of a battery, its health may deteriorate, which may result in a reduced power output of the battery or its capacity. One way to determine the health of a battery is by measuring and evaluating its impedance. Impedance measurement is done by injecting a sinusoidal current into the battery terminals and measuring the injected sinusoidal current and the voltage across the battery. The battery impedance is then estimated by using the sinusoidal current and the measured battery voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A complete and enabling disclosure of the invention, including the best mode thereof, is set forth to one of ordinary skill in the art in the specification made with reference to the accompanying drawings, in which:

[0005] Figure 1 is a top view schematic diagram of an aircraft and its power distribution system according to various aspects described herein.

[0006] Figure 2 It is suitable for Figure 1 A schematic circuit diagram of a battery monitoring circuit used in an aircraft, wherein the battery monitoring circuit is used to monitor the health of a group of batteries, and the battery monitoring circuit includes a first current loop, a second current loop, a third current loop and a fourth current loop.

[0007] Figure 3 is through the use of Figure 2 The battery monitoring circuit is a method of determining the health of a group of batteries.

[0008] Figure 4 It is suitable for Figure 1 A schematic circuit diagram of an exemplary battery monitoring circuit for use in an aircraft, the battery monitoring circuit being used to monitor the health of a group of batteries, the battery monitoring circuit comprising a first current loop, a second current loop, a third current loop, and a fourth current loop.

[0009] Figure 5 It is suitable for Figure 1A schematic circuit diagram of an exemplary battery monitoring circuit for use in an aircraft, the battery monitoring circuit being used to monitor the health of a group of batteries, the battery monitoring circuit comprising a first current loop, a second current loop, and a third current loop. DETAILED DESCRIPTION

[0010] Various aspects of the disclosure described herein are directed to a battery monitoring circuit for monitoring the health of a group of batteries. The battery monitoring circuit includes at least a first current loop and a second current loop. The second current loop has an impedance analyzer. The battery monitoring circuit will be described based on a battery monitoring circuit for a group of batteries provided on an aircraft or otherwise used for avionics purposes. However, it will be understood that the present disclosure is not limited to battery monitoring circuits for aircraft, and that it has general applicability in non-aircraft applications (including other mobile applications and non-mobile industrial, commercial, and residential applications). For example, applicable mobile environments may include aircraft, spacecraft, space launch vehicles, satellites, locomotives, automobiles, etc. Commercial environments may include manufacturing facilities or power generation and distribution facilities or infrastructure.

[0011] Although a "group" of various elements will be described, it will be understood that a "group" may include any number of corresponding elements, including only one element. For example, as used herein, the term "a group of batteries" may refer to a single battery including a single battery cell, or a plurality of batteries (each battery including a group of corresponding battery cells). In addition, as used herein, the term "battery" or its iteration may refer to a single battery cell or a battery module. Each battery module includes a plurality of battery cells coupled to each other in series and in parallel. Thus, a group of batteries may, for example, include a plurality of battery modules, each of which includes a group of battery cells.

[0012] The use of the terms "nearby" or "nearly" refers to movement in a direction toward another component, or a component being relatively closer to another component as compared to another reference point. Also as used herein, although a sensor may be described as "sensing" or "measuring" a corresponding value, sensing or measuring may include determining a value indicative of or associated with the corresponding value, rather than directly sensing or measuring the value itself. The sensed or measured value may be further provided to an additional component. For example, the value may be provided to a controller module or processor, and the controller module or processor may process the value to determine a representative value or electrical characteristic representing the value. In addition, although terms such as "voltage", "current", and "power" may be used herein, it is apparent to those skilled in the art that these terms may be interrelated when describing various aspects of a circuit or circuit operation.

[0013] Unless otherwise indicated, connection references (e.g., attachment, coupling, connection, and engagement) should be interpreted broadly and may include intermediate members between a collection of elements and relative movement between elements. Therefore, a connection reference does not necessarily imply that two elements are directly connected and are in a fixed relationship to each other. In a non-limiting example, the connection or disconnection can be selectively configured, connected, or connectable to provide, enable, disable, etc., electrical connections between corresponding elements. Non-limiting example power distribution bus connection or disconnection can be enabled or operated by switches, bus connection logic, or any other connector configured to enable or disable energization of electrical loads downstream of the bus or between buses.

[0014] Directional references (eg, upstream and downstream) are used with respect to an electrical circuit. As used herein, the term "directional reference" with respect to an electrical circuit is with respect to the flow of current within the circuit.

[0015] As used herein, a "system" or "controller module" may include at least one processor and memory. Non-limiting examples of memory may include random access memory (RAM), read-only memory (ROM), flash memory, or one or more different types of portable electronic memory (e.g., optical disks, DVDs, CD-ROMs, etc.) or any suitable combination of these types of memory. The processor may be configured to run any suitable program or executable instruction designed to implement various methods, functionalities, processing tasks, calculations, etc. to enable or implement one or more technical operations described herein. The program may include a computer program product that may include a machine-readable medium for carrying or having machine-executable instructions or data structures stored thereon. Such a machine-readable medium may be any available medium that can be accessed by a general-purpose or special-purpose computer or other machine with a processor. Typically, such a computer program may include routines, programs, objects, components, data structures, algorithms, etc., which have the technical effect of performing a specific task or realizing a specific abstract data type.

[0016] As used herein, a controllable switch element or "switch" is an electrical device that can be controlled to switch between a first operating mode (wherein the switch is "closed" to transfer current from the switch input to the switch output) and a second operating mode (wherein the switch is "open" to prevent current from being transferred between the switch input and the switch output). In a non-limiting example, a connection or disconnection (e.g., a connection enabled or disabled by a controllable switch element) can be selectively configured to provide, enable, disable, etc. an electrical connection between the corresponding elements.

[0017] Aspects of the present disclosure may be used in any circuit environment including a power source for delivering power to a load. A non-limiting example of such a circuit environment may be an aircraft power system architecture, which is capable of generating electrical power from at least one rotating shaft of a turbine engine and delivering the electrical power to a group of electrical loads through a power converter. A typical power converter is a power processing circuit that converts an input voltage into a specified output voltage. A controller may be associated with a power converter to control its operation by selectively controlling the conduction period of the switch employed therein. The switch employed by the power converter is typically a semiconductor switching device (e.g., MOSFET). Although various non-limiting aspects are depicted and described herein using various semiconductor switching devices such as MOSFET, other aspects are less restrictive. Other non-limiting aspects may include any desired switching device capable of switching a state between a low resistance state and a high resistance state in response to an electrical signal. For example, the switching devices of various aspects may include, but are not limited to, any desired type of switching element, including, for example, transistors, gate-commutated thyristors, field effect transistors (FETs), insulated gate bipolar transistors (IGBTs), MOSFETs, etc.

[0018] The exemplary drawings are for illustrative purposes only, and the dimensions, positions, orders, and relative sizes reflected in the drawings attached hereto may vary.

[0019] Figure 1 1 is a schematic diagram of an aircraft 10. The aircraft 10 may have a power system. The power system may, for example, include at least one turbine engine, shown as a left engine system 12 and a right engine system 14. The left engine system 12 and the right engine system 14 may be substantially identical, and may further include at least one power source, shown as a set of generators 18, respectively. At least one of the set of generators 18 may include a variable speed or variable output generator. In this example, the variable speed or variable output generator may include a generator adapted or configured to operate within a predetermined range of input speed, gearbox speed ratio, etc., and may generate a power output within a predetermined output range (e.g., a voltage output range, a current output range, a frequency output range, or a combination thereof). In a non-limiting example, the variable output generator may include a generator adapted or configured to output approximately 115 volts AC between 390 Hz and 410 Hz.

[0020] The aircraft 10 is also shown having a set of power consuming components or electrical loads 20, such as, for example, actuator loads, flight critical loads, and non-flight critical loads. The electrical loads 20 are electrically coupled to at least one of the generators 18 via a power distribution system 30 that includes, for example, a transmission line 22, a bus bar, a power bus (or the like) and a set of distribution nodes 16.

[0021] The aircraft 10 may also include a set of batteries 24 that are selectively connectable to the power transmission line 22 and operable to provide at least a portion of the following to at least a portion of the aircraft 10: primary power, supplemental power, redundant power, backup power, emergency power, etc. As shown, the set of batteries 24 can provide power to the set of power transmission lines 22 and thereby provide power to the set of power distribution nodes 16 or the set of electrical loads 20.

[0022] In the aircraft 10, the operating left and right engine systems 12, 14 provide mechanical energy (which is typically extracted via a rotating shaft) to provide driving force for the set of generators 18. The set of generators 18 in turn generates power (e.g., AC or DC power) and provides the generated power to a power transmission line 22, which delivers the power to electrical loads 20 located throughout the aircraft 10. In addition, during operation, the set of batteries 24 can be selectively connected to the power transmission line 22 and can be operated to provide primary power or supplemental power to a subset of the electrical loads 20.

[0023] Example power distribution management functions may include, but are not limited to, selectively enabling or disabling power delivery to specific electrical loads 20 depending on, for example, available power distribution supplies, criticality of electrical load 20 functionality, or aircraft operating mode (e.g., takeoff, cruise, or ground operations). During emergency or insufficient periods of electrical power generation (including, but not limited to, engine or generator failures), at least one of the supplemental power batteries 24 may be operated, enabled, or connected for providing power to the electrical loads 20. Additional management functions may be included.

[0024] It will be understood that while aspects of the present disclosure are Figure 1 The present disclosure is illustrated in the context of an aircraft, but the present disclosure is not so limiting and may have applicability in a variety of contexts. For example, while the present description is directed to a power system architecture in an aircraft, aspects of the present disclosure may also be applicable to providing power, supplemental power, emergency power, necessary power, etc. in other non-emergency operations (e.g., takeoff, landing, or cruise flight operations).

[0025] also, Figure 1 The number and placement of the various components depicted in the drawings are also non-limiting examples of aspects associated with the present disclosure. For example, although various components have been shown with relative locations of the aircraft 10 (e.g., electrical loads 20 on the wings of the aircraft 10, etc.), aspects of the present disclosure are not so limiting, and the components are not so limiting based on their schematic depictions. Additional aircraft 10 configurations are foreseen.

[0026] Figure 2 It is suitable for Figure 11 is a schematic circuit diagram of a battery monitoring circuit 100 for use within an aircraft 10 of the type shown in FIG. 1. Although described with respect to the aircraft 10, it will be appreciated that the battery monitoring circuit 100 may be used within any suitable aircraft or non-aircraft application. As non-limiting examples, the battery monitoring circuit 100 may be used on an aircraft, off an aircraft (e.g., testing of aircraft components), or in a non-aircraft application.

[0027] The battery monitoring circuit 100 can be selectively coupled to a group of batteries 102. The battery monitoring circuit 100 includes a first terminal (Tr1) and a second terminal (Tr2). The first terminal (Tr1) can be a positive terminal, and the second terminal (Tr2) can be a negative terminal, so that current can flow from the first terminal (Tr1) to the second terminal (Tr2) via an electrical load.

[0028] The first switch 104 may be arranged downstream of the first terminal (Tr1) and connected in series therewith. The second switch 106 may be arranged upstream of the second terminal (Tr2) and connected in series therewith. The first node (n1) may be arranged downstream of the first switch 104. The first capacitor 118 may be arranged downstream of the first node (n1). The second node (n2) may be arranged downstream of the first capacitor 118. The third node (n3) may be arranged downstream of the second node (n2). The third switch 108 may be arranged downstream of the third node (n3). The fourth switch 110 may be arranged downstream of the third switch 108 and connected in series therewith. The fourth node (n4) may be arranged downstream of the fourth switch 110. The fifth node (n5) may be arranged downstream of the fourth switch (n4). The second capacitor 120 may be arranged downstream of the fifth node (n5). The sixth node (n6) may be arranged downstream of the second capacitor 120. The second switch 106 may be arranged downstream of the sixth node (n6).

[0029] First switch 104, second switch 106, third switch 108, and fourth switch 110 may be any suitable components of battery monitoring circuit 100 for selectively opening or closing various portions of battery monitoring circuit 100. As non-limiting examples, first switch 104, second switch 106, third switch 108, and fourth switch 110 may be mechanical switches or solid-state switches.

[0030] The first resistor 112 may be disposed on a branch of the battery monitoring circuit 100 extending between the third node (n3) and the fourth node (n4). The first resistor 112 may define a first resistance. The second resistor 114 may be disposed on a branch of the battery monitoring circuit 100 extending between the second node (n2) and the fifth node (n5). The second resistor 114 may define a second resistance. The third resistor 116 may be disposed on a branch of the battery monitoring circuit 100 extending between the first node (n1) and the sixth node (n6). The third resistor 116 may define a third resistance.

[0031] At least two of the first resistance, the second resistance, and the third resistance may be equal or unequal. As a non-limiting example, the first resistance may be lower than the second resistance and the third resistance. As a non-limiting example, the first resistance may be lower than the second resistance and the third resistance, wherein the second resistance is equal to the third resistance.

[0032] Although a single resistor is shown for the first resistor 112 , the second resistor 114 , and the third resistor 116 , it will be appreciated that at least one of the first resistor 112 , the second resistor 114 , and the third resistor 116 may include two or more resistors connected in series.

[0033] The voltage sensor 150 may be disposed downstream of and in series with the third switch 108 and upstream of and in series with the fourth switch 110. The voltage sensor 150 may be any suitable component in the battery monitoring circuit 100 for measuring the voltage seen across the voltage sensor 150. As a non-limiting example, the voltage sensor 150 may be an impedance analyzer.

[0034] The battery monitoring circuit 100 may include a plurality of current loops. As non-limiting examples, the battery monitoring circuit 100 may define a first current loop 124, a second current loop 126, a third current loop 128, a fourth current loop 130, or a combination thereof.

[0035] The first current loop 124 can be enabled by at least the first switch 104, the first node (n1), the first capacitor 118, the second node (n2), the third node (n3), the first resistor 112, the fourth node (n4), the fifth node (n5), the second capacitor 120, the sixth node (n6), the second switch 106, or any combination thereof arranged in series. As used herein, the term "enable" when used in terms of a current loop can refer to providing a current or applying a voltage to the corresponding current loop or through the corresponding current loop. The first current loop 124 can be connected in parallel with the second resistor 114, the third resistor 116, and the voltage sensor 150.

[0036] The second current loop 126 may be arranged in parallel with the first current loop 124 and at least partially downstream thereof. The second current loop 126 may be enabled by the first switch 104, the first node (n1), the first capacitor 118, the second node (n2), the third node (n3), the third switch 108, the voltage sensor 150, the fourth switch 110, the fourth node (n4), the fifth node (n5), the second capacitor 120, the sixth node (n6), the second switch 106, or any combination thereof, arranged in series. The second current loop 126 may be connected in parallel with the first resistor 112, the second resistor 114, and the third resistor 116.

[0037] The third current loop 128 can be arranged in parallel with the first current loop 124 and the second current loop 126 and at least partially upstream thereof. The third current loop 128 can be enabled by the first switch 104, the first node (n1), the first capacitor 118, the second node (n2), the second resistor 114, the fifth node (n5), the second capacitor 120, the sixth node (n6), the second switch 106, or any combination thereof arranged in series. The third current loop 128 can be connected in parallel with the first resistor 112, the third resistor 116, and the voltage sensor 150.

[0038] The fourth current loop 130 may be arranged in parallel with the first current loop 124, the second current loop 126, and the third current loop 128 and at least partially upstream thereof. The fourth current loop 130 may be enabled by the first switch 104, the first node (n1), the third resistor 116, the sixth node (n6), the second switch 106, or any combination thereof arranged in series. The fourth current loop 130 may be connected in parallel with the first resistor 112, the second resistor 114, and the voltage sensor 150.

[0039] A controller module 152 having a processor 154 and a memory 156 may be communicatively coupled to the battery monitoring circuit 100. The memory 156 may be defined as an internal memory used for various aspects of the battery monitoring circuit 100. For example, the memory 156 may store code, executable instructions, commands, instructions, authorization keys, private data keys, passwords, etc. The memory 156 may be RAM, ROM, flash memory, or one or more different types of portable electronic memory (e.g., optical disks, DVDs, CD-ROMs, etc.) or any suitable combination of these types of memory. The processor 154 may be defined as a portion of the controller module 152 that may receive input, perform calculations, and output executable data. The processor 154 may be a microprocessor. The controller module 152 may be further defined as a portion of the set of batteries 102 or otherwise used in conjunction with the set of batteries 102. As a non-limiting example, the controller module 152 may be included in a battery management system or otherwise form a battery management system.

[0040] It will be appreciated that various portions of the battery monitoring circuit 100 may be included or excluded. As a non-limiting example, the battery monitoring circuit 100 may be formed without the fourth switch 110 or the second switch 106. As a non-limiting example, the battery monitoring circuit 100 may be formed with fewer or additional current loops. As a non-limiting example, the battery monitoring circuit may be formed without the first capacitor 118 or the second capacitor 120.

[0041] Figure 3 is through the use of Figure 2 The battery monitoring circuit 100 determines the group of batteries 102 ( Figure 2 ) of the health method 140. By combining method 140 with Figure 2 The battery monitoring circuit 100 and the physical aspects of the set of batteries 102 described in Figure 2 and Figure 3 Make a reference.

[0042] The method 140 may include closing the first switch 104 and the second switch 106 at a first time at 142. It will be appreciated that the first time may be a specific time for both the first switch 104 and the second switch 106 (e.g., at time=0 seconds), or a time frame for the first switch 104 and the second switch 106 to be closed (e.g., between time=0 seconds and time=1 second). Closing at the first time may enable at least the first current loop 124. Closing at the first time may further include enabling the first current loop 124, the third current loop 128, and the fourth current loop 130. As a non-limiting example, closing the first switch 104 and the second switch 106 enables current from the group of batteries 102 to be supplied to at least a portion of the battery monitoring circuit 100. As a non-limiting example, at the first time, the third switch 108 may be open so that current flows only through the first current loop 124, the third current loop 128, and the fourth current loop 130. It is expected that when the first switch 104 and the second switch 106 are closed, a majority of the current from the set of batteries 102 will flow through the first current loop 124 due to the lower rating of the first resistor 112 relative to at least the second resistor 114 and the third resistor 116. Therefore, the first current loop 124 can be defined as a main current loop.

[0043] At 144, at least the third switch 108 may be closed at a second time. It will be appreciated that the second time may be a specific time greater than the first time (e.g., when the time > the first time), where the third switch 108 is closed, or a time frame after the first time (e.g., between >0 seconds and ≤1 second after the first time), where the third switch 108 is closed. Closing at the second time may enable the second current loop 126. It will be appreciated that the fourth switch 110 may optionally be included. In such a case where the fourth switch 110 is included, the method may include closing the third switch 108 and the fourth switch 110 at the second time at 144. When the third switch 108, and optionally the fourth switch 110 (if the fourth switch 110 is included), is closed at the second time, at least a portion of the current that has flowed through the battery monitoring circuit 100 from the group of batteries 102 may be supplied to the second current loop 126.

[0044] The second time may be after the first time. As a non-limiting example, the second time may be greater than or equal to 0.5 seconds after the first time and less than or equal to 1.5 seconds after the first time.

[0045] At 146, the voltage sensor 150 may measure the voltage between the second node (n2) and the third node (n3). At 148, based on the measured voltage, the impedance of the group of batteries 102 may be determined. The determined impedance may be used to determine the state of health of the group of batteries 102 and indicate whether the group of batteries 102 is in a healthy state or an unhealthy state. As used herein, the term "determined" may include the calculation of an exact value or an estimate of a value.

[0046] The use of the battery monitoring circuit 100 ensures that the voltage experienced at the voltage sensor 150 is within the voltage threshold that can be handled by the voltage sensor. As a non-limiting example, the voltage sensor 150 may be rated for a maximum voltage of 10 volts, however, the group of batteries 102 may output a voltage greater than 10 volts. At least the first current loop 124 and optionally also the third current loop 128 or the fourth current loop 130 may be used to reduce the voltage experienced at the voltage sensor 150.

[0047] It is contemplated that the battery monitoring circuit 100 may step down a first voltage directly from the set of batteries 102 (eg, supplied directly to the first switch 104 ) to a second voltage experienced at the voltage sensor 150 .

[0048] As a non-limiting example, Table 1 below has been provided to illustrate an example environment where the output of the set of batteries 102 is 800 volts. Table 1 illustrates the voltage experienced at each of the nodes (n1-n6) along with the voltage experienced at the voltage sensor 150 relative to the sixth node (n6). Table 1

[0049] The voltage reduction from the first voltage to the second voltage may allow the use of a voltage sensor 150 having a low voltage rating. For example, if the voltage was not reduced and the voltage experienced at the voltage sensor 150 was equal to or close to the first voltage, a much higher rating of the voltage sensor 150 would be required, which may be impossible or otherwise very expensive to implement.

[0050] It will be appreciated that the method 140 is flexible. For example, the order of steps depicted is for illustrative purposes only and is not meant to limit the method 140 in any way, as it is understood that the steps may be performed in a different logical order or may include additional or intermediate steps without departing from embodiments of the present disclosure.

[0051] As a non-limiting example, method 140 may include rating first resistor 112 to have a first resistance lower than a second resistance of second resistor 114 or a third resistance of third resistor 116 . This in turn enables a majority of current from the group of batteries 102 to flow through first current loop 124 .

[0052] As a non-limiting example, the method 140 may include opening at least the third switch 108 and optionally also the fourth switch 110 before or during the first time. This in turn may ensure that current from the group of batteries 102 does not flow through the second current loop 126 at the first time.

[0053] As a non-limiting example, the method 140 may include, at 146, injecting a sinusoidal current into the second current loop 126 by the voltage sensor 150 while the voltage sensor 150 is measuring the voltage. The voltage sensor 150 may then inject the sinusoidal current into the second current loop 126 and measure the voltage for a set amount of time and use these measurements to estimate or otherwise determine the impedance of the group of batteries 102. It is contemplated that the measurement at 146 and the determination at 148 may be performed by the voltage sensor 150.

[0054] Alternatively, the method 140 may include receiving the measured voltage at the controller module 152 after the measurement at 146. At 148, the controller module 152 may then use the measured voltage and the processor 154 to determine the voltage.

[0055] As a non-limiting example, the method 140 may include, at 142, closing, by the controller module 152, the first switch 104 and the second switch 106 at a first time. The method 140 may include, at 144, closing, by the controller module 152, at least the third switch 108 and optionally also the fourth switch 110 at a second time. The third switch 108 and the fourth switch 110 may be closed simultaneously or at different times relative to each other. As a non-limiting example, the method 140 may include retrieving an executable runtime function of the battery monitoring circuit from the memory 156 or a memory accessible by the controller module 152, and further operating the battery monitoring circuit 100 by the controller module 152 according to the executable runtime function. The executable runtime function may be any suitable set of commands or instructions for operating the battery monitoring circuit 100 according to the desired operating parameters. As a non-limiting example, the executable runtime function may include the open or closed state of the first switch 104, the second switch 106, the third switch 108, and the fourth switch 110 at the first time, the second time, or any other time. Using this information, the controller module 152 can then send commands to the first switch 104, the second switch 106, the third switch 108, and the fourth switch 110 to open or close based on time. The method 140 can include automatically running the executable runtime function. The method 140 can include receiving input from a user to cause the controller module 152 to run the executable runtime function.

[0056] Figure 4 It is suitable for Figure 1 1 is a schematic circuit diagram of an exemplary battery monitoring circuit 200 for use within an aircraft 10 of the type shown in FIG. The battery monitoring circuit 200 is similar to the battery monitoring circuit 100 and, therefore, like parts will be identified with like numerals incremented into the 200 series, with the understanding that the description of the battery monitoring circuit 100 applies to the battery monitoring circuit 200 unless otherwise noted.

[0057] The battery monitoring circuit 200 can be selectively coupled to a group of batteries 202. The group of batteries 202 can have a first terminal (Tr1) and a second terminal (Tr2). A first switch 204 can be downstream of the first terminal (Tr1) and in series with it. A second switch 206 can be upstream of the second terminal (Tr2) and in series with it. The battery monitoring circuit 200 may include a first node (n1) downstream of and in series with the first switch 204, a first capacitor 218 may be downstream of and in series with the first node (n1), a second node (n2) may be downstream of and in series with the first capacitor 218, a third switch 208 may be downstream of and in series with the second node (n2), a voltage sensor 250 may be downstream of and in series with the third switch 208, a fourth switch 210 may be downstream of and in series with the voltage sensor 250, a third node (n3) may be downstream of and in series with the fourth switch 210, a second capacitor 220 may be downstream of and in series with the third node (n3), a fourth node (n4) may be downstream of and in series with the second capacitor 220, a second switch 206 may be downstream of and in series with the fourth node (n4), or any combination thereof. Although not shown, a controller module (e.g., Figure 2 The controller module 152) can be communicatively coupled to the battery monitoring circuit 200.

[0058] The first resistor 212 may be disposed on a branch between the second node (n2) and the third node (n3). The second resistor 214 may be disposed on a branch between the first node (n1) and the sixth node (n6).

[0059] The first current loop 224 may be enabled by the first switch 204, the first node (n1), the first capacitor 218, the second node (n2), the first resistor 212, the third node (n3), the second capacitor 220, the fourth node (n4), the second switch 206, or a combination thereof, which are arranged in series. The second current loop 226 may be enabled by the first switch 204, the first node (n1), the first capacitor 218, the second node (n2), the third switch 208, the voltage sensor 250, the fourth switch 210, the third node (n3), the second capacitor 220, the fourth node (n4), the second switch 206, or a combination thereof, which are arranged in series. The third current loop 228 may be enabled by the first switch 204, the first node (n1), the second resistor 214, the fourth node (n4), the second switch 206, or a combination thereof, which are arranged in series.

[0060] The battery monitoring circuit 200 is similar to the battery monitoring circuit 100 ( Figure 2 ) because it includes the first current loop 224, the second current loop 226, and the third current loop 228. However, the difference is that the resistor with the lowest rating (e.g., Figure 2 The first resistor 112 of the battery monitoring circuit 200 is removed and replaced with a transient voltage suppressor 222, which is disposed downstream of the third switch 208 and in series with it, and upstream of the fourth switch 210 and in series with it. The transient voltage suppressor 222 can be any suitable component of the battery monitoring circuit 200 that suppresses or otherwise reduces transient overvoltages. As a non-limiting example, the transient voltage suppressor 222 can be a diode. The transient voltage suppressor 222 can be connected in parallel with the voltage sensor 250.

[0061] Therefore, the second current loop can be enabled by the first switch 204, the first node (n1), the first capacitor 218, the second node (n2), the third switch 208, the voltage sensor 250, the transient voltage suppressor 222 in parallel with the voltage sensor 250, the fourth switch 210, the third node (n3), the second capacitor 220, the fourth node (n4), the second switch 206, or a combination thereof arranged in series.

[0062] Figure 5 It is suitable for Figure 1 1 is a schematic circuit diagram of an exemplary battery monitoring circuit 300 for use within an aircraft 10 of the type shown in FIG. The battery monitoring circuit 300 is similar to the battery monitoring circuits 100, 200 and, therefore, like parts will be identified with like numerals incremented to the 300 series, with the understanding that the description of the battery monitoring circuits 100, 200 applies to the battery monitoring circuit 300 unless otherwise noted.

[0063] The battery monitoring circuit 300 can be selectively coupled to a group of batteries 302. The group of batteries 302 can have a first terminal (Tr1) and a second terminal (Tr2). A first switch 304 can be downstream of the first terminal (Tr1) and in series with it. A second switch 306 can be upstream of the second terminal (Tr2) and in series with it. The battery monitoring circuit 300 may include a first node (n1) downstream of and in series with the first switch 304, a first capacitor 318 may be downstream of and in series with the first node (n1), a second node (n2) may be downstream of and in series with the first capacitor 318, a third switch 308 may be downstream of and in series with the second node (n2), a voltage sensor 350 may be downstream of and in series with the third switch 308, a fourth switch 310 may be downstream of and in series with the voltage sensor 350, a third node (n3) may be downstream of and in series with the fourth switch 310, a second capacitor 320 may be downstream of and in series with the third node (n3), a fourth node (n4) may be downstream of and in series with the second capacitor 320, a second switch 306 may be downstream of and in series with the fourth node (n4), or any combination thereof. Although not shown, a controller module (e.g., Figure 3 The controller module 152) can be communicatively coupled to the battery monitoring circuit 300.

[0064] The first resistor 312 may be disposed on a branch between the third node (n3) and the fourth node (n4). The second resistor 314 may be disposed on a branch between the second node (n2) and the fifth node (n5).

[0065] The first current loop 324 may be enabled by the first switch 304, the first node (n1), the first capacitor 318, the second node (n2), the first resistor 312, the third node (n3), the second capacitor 320, the fourth node (n4), the second switch 306, or a combination thereof, which are arranged in series. The second current loop may be enabled by the first switch 304, the first node (n1), the first capacitor 318, the second node (n2), the third switch 308, the voltage sensor 350, the fourth switch 310, the third node (n3), the second capacitor 320, the fourth node (n4), the second switch 306, or a combination thereof, which are arranged in series. The third current loop 328 may be enabled by the first switch 304, the first node (n1), the second resistor 314, the fourth node (n4), the second switch 306, or a combination thereof, which are arranged in series.

[0066] The battery monitoring circuit 300 is similar to the battery monitoring circuit 100 ( Figure 2 )、200( Figure 4 ) because it includes the first current loop 324, the second current loop 326, and the third current loop 328. However, the battery monitoring circuit 300 does not include a minimum rated resistor (e.g., Figure 2 The first resistor 112) or the transient voltage suppressor 222 ( Figure 3 ) to reduce the voltage experienced at the voltage sensor 350. Instead, the battery monitoring circuit 300 reduces the voltage by setting at least one of the first switch 304, the second switch 306, the third switch 308, the fourth switch 310, or a combination thereof as a semiconductor-based power switch. It is contemplated that a semiconductor-based power switch may be used to at least partially reduce the voltage experienced at the voltage sensor 350. As a non-limiting example, at least one of the first switch 304 or the third switch 308 may be a semiconductor-based power switch that reduces the voltage upstream of the voltage sensor 350. Thus, the need for an additional resistor (e.g., Figure 2 The need for the first resistor 112) or the transient voltage suppressor 222 is eliminated.

[0067] It will be appreciated that any combination of current loops as described herein is contemplated. As a non-limiting example, the exemplary battery monitoring circuit may include only the first current loop 124 ( Figure 2 )、224( Figure 4 )、324( Figure 5 ) and the second current loop 126 ( Figure 2 )、226( Figure 4 )、326( Figure 5 ). As a non-limiting example, the exemplary battery monitoring circuit may include any number of two or more current loops, wherein a second one of the current loops includes a voltage sensor.

[0068] Benefits associated with the present disclosure include lower cost and less complex battery monitoring circuits when compared to conventional battery monitoring circuits. For example, conventional battery monitoring circuits that rely on determining the impedance of the group of batteries may rely on voltage sensors with high ratings or otherwise rely on complex systems including an impedance network that requires a processing unit to determine the impedance of the battery module to which the conventional battery monitoring circuit is coupled. The processing unit requires an independent power source. When compared to the battery monitoring circuit as described herein, the processing unit and power source are relatively expensive and greatly increase the complexity of the circuit. However, the battery monitoring circuit as described herein utilizes a relatively simple combination of a current loop and an operating method to reduce the voltage experienced at the voltage sensor. This in turn results in a less complex battery monitoring circuit that has a reduced burden and manufacturing cost when compared to conventional battery monitoring circuits. In addition, as the voltage from the group of batteries to the voltage sensor is reduced, a voltage sensor with a relatively low voltage rating can be used. This in turn greatly reduces the cost associated with the voltage sensor when compared to a conventional voltage sensor provided within a conventional battery monitoring circuit.

[0069] To the extent not yet described, the different features and structures of each aspect can be used in combination or replaced with each other as needed. The fact that a feature is not shown in all examples does not mean that it cannot be so shown, but it is done so for the simplicity of description. Therefore, various features of different aspects can be mixed and matched as needed to form new aspects, whether or not the new aspects are explicitly described. This disclosure covers all combinations or arrangements of the features described herein.

[0070] This written description uses examples, including the best mode, to describe the various aspects of the disclosure described herein, and also enables those skilled in the art to practice the various aspects of the disclosure, including making and using any device or system and performing any combined method. The patentable scope of the various aspects of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples have structural elements that are not different from the literal language of the claims, or if such other examples include equivalent structural elements that are not substantially different from the literal language of the claims, such other examples are intended to be within the scope of the claims.

[0071] Further aspects of the disclosure are provided by the subject matter of the following clauses:

[0072] A method for monitoring a group of batteries by a battery monitoring circuit that can be electrically coupled to the group of batteries, the method comprising: closing a first switch and a second switch at a first time, thereby enabling a first current loop defined by at least the first switch, a first resistor, and the second switch in series, the first current loop defining a first current that can be supplied from the group of batteries; closing a third switch at a second time after the first time, thereby enabling a second current loop defined by the third switch and an impedance analyzer connected in series with the third switch, the second current loop being connected in parallel with the first resistor, wherein the second current loop defines a second current that is less than the first current; measuring, by the impedance analyzer, a voltage experienced at the impedance analyzer based on the second current; and determining the impedance of the group of batteries by the measured voltage.

[0073] A battery monitoring circuit for monitoring a group of batteries that can be electrically coupled to the battery monitoring circuit, the battery monitoring circuit comprising: a first current loop having a first current that can be supplied from the group of batteries, the first current loop being defined by the following items: a first switch; a first resistor; and a second switch, wherein the first switch, the first resistor, and the second switch are connected in series; a second current loop having a second current that is less than the first current, the second current loop being connected in parallel with the first current loop and being defined by the following items: a third switch; and a voltage sensor connected in series with the third switch; and a controller module configured to: close the first switch and the second switch at a first time, thereby enabling the first current loop; close the third switch at a second time after the first time, thereby enabling the second current loop; receive a value corresponding to a measured voltage at the voltage sensor from the voltage sensor; and determine the impedance of the group of batteries based at least in part on the measured voltage.

[0074] The method of any preceding clause, further comprising closing the first switch and the second switch at the first time, thereby enabling the second current loop defined by the first switch, the first capacitor, the first resistor, the second capacitor, and the second switch arranged in series.

[0075] A method as described in any of the preceding clauses, further comprising closing the first switch and the second switch at the first time, thereby enabling a third current loop defined by the first switch, the first capacitor, the second resistor, the second capacitor and the second switch arranged in series, wherein the third current loop is connected in parallel with and upstream of the first current loop.

[0076] A method as in any preceding clause, further comprising rating the first resistor to have a lower resistance than a resistance of the second resistor.

[0077] The method as described in any of the preceding clauses further includes closing the first switch and the second switch at the first time, thereby enabling a fourth current loop defined by the first switch, the third resistor and the second switch arranged in series, wherein the fourth current loop is connected in parallel with and upstream of the first current loop and the third current loop.

[0078] A method as in any preceding clause, further comprising rating the first resistor to have a lower resistance than a resistance of the second resistor and a resistance of the third resistor.

[0079] A method as in any preceding clause, further comprising providing the fourth current loop upstream of the first capacitor and downstream of the second capacitor.

[0080] A method as in any preceding clause, further comprising positioning a transient voltage suppressor along the second current loop in parallel with the impedance analyzer.

[0081] The method of any preceding clause, further comprising opening the third switch before closing the first switch and the second switch.

[0082] The method of any preceding clause, further comprising closing the third switch and the fourth switch at the first time, thereby enabling the second current loop defined by the third switch, the impedance analyzer, and the fourth switch arranged in series.

[0083] A method as in any preceding clause, further comprising determining the impedance via the measured voltage and a controller module.

[0084] A method as in any preceding clause, further comprising providing the battery monitoring circuit on an aircraft or turbine engine comprising the set of batteries.

[0085] A method as in any preceding clause, further comprising closing the third switch at the second time that is greater than or equal to 0.5 seconds after the first time and less than or equal to 1.5 seconds after the first time.

[0086] The method of any preceding clause, further comprising estimating the impedance of the group of batteries via the impedance analyzer.

[0087] A method as in any preceding clause, further comprising configuring at least one of the first switch or the third switch as a semiconductor-based power switch.

[0088] A battery monitoring circuit as described in any preceding clause, wherein the first current loop further includes: a first capacitor downstream of the first switch and upstream of the first resistor; and a second capacitor downstream of the first resistor and upstream of the second switch.

[0089] A battery monitoring circuit as described in any of the preceding clauses, further comprising a third current loop defined by: the first switch; the first capacitor downstream of the first switch; a second resistor downstream of the first capacitor; the second capacitor downstream of the second resistor; and the second switch.

[0090] A battery monitoring circuit as described in any preceding clause, wherein the first resistor has a lower resistance than a resistance of the second resistor.

[0091] A battery monitoring circuit as described in any preceding clause, wherein the voltage sensor is an impedance analyzer.

Claims

1. A method of monitoring a group of batteries by a battery monitoring circuit electrically coupled to the group of batteries, the method comprising: closing a first switch and a second switch at a first time, thereby enabling a first current loop defined by at least the first switch, a first resistor, and the second switch connected in series, the first current loop defining a first current supplyable from the group of batteries; closing a third switch at a second time after the first time, thereby enabling a second current loop defined by the third switch and an impedance analyzer connected in series with the third switch, the second current loop being connected in parallel with the first resistor, wherein the second current loop defines a second current that is less than the first current; measuring, by the impedance analyzer, a voltage experienced at the impedance analyzer based on the second current; and The impedance of the group of batteries is determined from the measured voltage.

2. The method of claim 1, further comprising closing the first switch and the second switch at the first time, thereby enabling the second current loop defined by the first switch, the first capacitor, the first resistor, the second capacitor, and the second switch arranged in series.

3. The method according to claim 2, further comprising closing the first switch and the second switch at the first time, thereby enabling a third current loop defined by the first switch, the first capacitor, the second resistor, the second capacitor, and the second switch arranged in series, wherein the third current loop is connected in parallel with and upstream of the first current loop. 4 . The method of claim 3 , further comprising rating the first resistor to have a lower resistance than the resistance of the second resistor.

5. The method of claim 3, further comprising closing the first switch and the second switch at the first time, thereby enabling a fourth current loop defined by the first switch, a third resistor, and the second switch arranged in series, wherein the fourth current loop is connected in parallel with and upstream of the first current loop and the third current loop. 6 . The method of claim 5 , further comprising rating the first resistor to have a lower resistance than a resistance of the second resistor and a resistance of the third resistor. 7 . The method of claim 5 , further comprising providing the fourth current loop upstream of the first capacitor and downstream of the second capacitor.

8. The method according to any one of claims 1 to 7, further comprising placing a transient voltage suppressor along the second current loop in parallel with the impedance analyzer.

9. The method of any one of claims 1-7, further comprising opening the third switch before closing the first switch and the second switch.

10. A battery monitoring circuit for monitoring a group of batteries electrically coupled to the battery monitoring circuit, the battery monitoring circuit comprising: a first current loop having a first current supplyable from the set of batteries, the first current loop being defined by: First switch; a first resistor; as well as a second switch, wherein the first switch, the first resistor, and the second switch are connected in series; A second current loop having a second current less than the first current, the second current loop being connected in parallel with the first current loop and being defined by: The third switch; as well as A voltage sensor connected in series with the third switch; and A controller module (152) configured to: Closing the first switch and the second switch at a first time, thereby enabling the first current loop; closing the third switch at a second time after the first time, thereby enabling the second current loop; receiving, from the voltage sensor, a value corresponding to a measured voltage at the voltage sensor; as well as An impedance of the group of batteries is determined based at least in part on the measured voltage.

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