Method for detecting a leak in an electrochemical device

Abstract

This article presents intelligent test systems for detecting leaks in electrochemical devices, methods for fabricating / using such test systems, and memory-stored instructions for automating the operation of such systems. One method for detecting a leak in an electrochemical device involves positioning a temperature-controlled (TC) shield with an electrothermal device at a predefined distance from an infrared camera to define a test envelope therebetween. A control unit of the test system commands the electrothermal device to change the operating temperature of the TC shield to a predefined shield test temperature. After positioning an electrochemical device in the test envelope between the TC shield and the infrared camera, the infrared camera captures infrared images of the electrochemical device in the test envelope, showing the device housing in front of the TC shield.The system control unit then analyzes the infrared images captured by the electrochemical device to determine if there is a gas leak in the device enclosure.

Description

[0001] The present disclosure relates generally to electrochemical devices. More specifically, aspects of this disclosure relate to systems and methods for detecting fluid leaks in cell casings during battery cell manufacturing.

[0002] Current production vehicles, such as the modern automobile, are originally equipped with a powertrain that propels the vehicle and supplies the on-board electronics. In automotive applications, for example, a vehicle's powertrain generally consists of a prime mover that transmits drive torque to the vehicle's final drive system (e.g., differential, axle shafts, cam modules, road wheels, etc.) via an automatic or manual transmission. Motor vehicles have traditionally been powered by a reciprocating internal combustion engine due to its readily available and relatively inexpensive design, lightweight construction, and high efficiency. Such engines include compression-ignition (CI) diesel engines, spark-ignition (SI) gasoline engines, two-, four-, and six-stroke engines, and rotary engines, to name a few.Hybrid electric and fully electric vehicles (collectively referred to as “electric propulsion vehicles”), on the other hand, use alternative energy sources to power the vehicle and therefore minimize or eliminate the need for a fossil fuel-based engine for traction power.

[0003] A fully electric vehicle (FEV), also colloquially referred to as an "electric car," is an electric-powered vehicle configuration that completely eliminates the internal combustion engine and its peripheral propulsion system components, instead utilizing a rechargeable energy storage system (RESS) and a traction motor for vehicle propulsion. The engine assembly, fuel supply system, and exhaust system of an internal combustion engine vehicle are replaced in a battery-powered FEV by one or more traction motors, rechargeable battery cells, and cooling and charging equipment. Hybrid electric vehicles (HEVs), on the other hand, utilize multiple power sources, typically an internal combustion engine combined with a battery- or fuel-cell-powered traction motor.Because hybrid-type electric vehicles can obtain their energy from sources other than the engine, the HEV engines can be fully or partially switched off while the vehicle is powered by the electric motor(s).

[0004] Many commercially available hybrid and fully electric vehicles have a rechargeable battery pack that stores and delivers the energy required to operate the traction motors. To generate traction power with sufficient range and speed, a battery pack is significantly larger, more powerful, and has a higher capacity (in amperes) than a standard 12-volt starting, lighting, and ignition (SLI) battery. In modern traction battery packs, for example, battery cell stacks (e.g., 12-75 cells / group) are grouped into individual battery modules (e.g., 10-40 modules / pack), which are mounted on the vehicle chassis using a battery pack enclosure or carrier. Stacked electrochemical battery cells can be connected in series or parallel using an electrical interconnect board (ICB) or a front-end DC bus assembly.A specialized electronic battery control module (EBCM), in conjunction with a powertrain control module (PCM) and a traction power inverter module (TPIM), controls the opening and closing of the battery pack contactors to control battery pack operation.

[0005] There are four main types of batteries used in electric vehicles: lithium batteries, nickel-metal hydride batteries, ultracapacitor batteries, and lead-acid batteries. Within lithium-class designs, lithium metal and lithium-ion (Li-ion) batteries make up the majority of commercial lithium battery (LiB) configurations, with Li-ion batteries being used in automotive applications due to their greater stability, energy density, and rechargeability. A standard lithium-ion cell generally consists of at least two conductive electrodes, an electrolyte material, and a permeable separator, all enclosed in an electrically insulated package. One electrode serves as the positive ("cathode") and the other electrode as the negative ("anode") electrode during cell discharge.The separator—often a microporous polymer membrane—is sandwiched between a pair of working electrodes to prevent electrical short circuits while allowing the transport of ionic charge carriers. Rechargeable lithium-ion batteries operate by reversibly shunting lithium ions between the negative and positive working electrodes. During the manufacturing of many lithium-ion battery cells, particularly prismatic lithium metal cells, a metered volume of compressed gas, such as carbon dioxide (CO2), is introduced into the cell's rigid battery casing to pressurize the cell. To ensure continuous and uninterrupted operation of the battery system, each cell is tested during the manufacturing process to ensure that there are no leaks in the cell casing.

[0006] DE 10 2023 126 184 A1 discloses a leak detection system for a battery case. A battery pack includes a gas supply system configured to selectively supply a trace gas to the battery case. A first optical gas imaging sensor is configured to generate images of a surface of the battery case after the gas supply system supplies the battery case with trace gas. The images are used to selectively detect a gas cloud adjacent to the surface of the battery case. The gas cloud is used to determine a location of a gas leak at the surface of the battery case.

[0007] WO 2021 / 094554 A2 discloses a method for testing the integrity of a disposable system for processing at least one liquid material, in particular for use in pharmaceutical processing. The method comprises the following steps: i.) Providing at least one disposable system for processing at least one fluid material, wherein the disposable system comprises at least one plastic component; ii.) Exposing at least one lumen of the disposable system to at least one test gas. The test gas has spectral absorption or spectral emission properties in the infrared spectral range that are distinguishable from ambient air; iii.) Monitoring at least part of the disposable system using an infrared camera.

[0008] DE 10 2021 120 269 A1 discloses a method for performing a leak test, comprising the steps of: providing a component for leak testing; introducing a test medium into the component, which is designed to flow out of the component in the event of a leak; providing an optical detection means, wherein the optical detection means is designed to optically detect any leakage flow in a test area; providing a suction device in the test area for aligning the leakage flow; and optically detecting the aligned leakage flow to generate image data.

[0009] The following describes intelligent test systems with control logic for detecting fluid leaks in electrochemical devices, methods for manufacturing and operating such test systems, and instructions stored in memory to automate the operation of such systems. By way of example, but not limitation, one automated system and method uses optical infrared gas imaging (OGI) sensors to enable inline detection of gas leaks in prismatic cell enclosures. Prismatic cells can be pressurized with CO2 or another compressed gas; each cell is scanned in the mid-infrared (MWIR) wavelength range against a heated backdrop to determine whether or not gas is leaking from the cell enclosure. The system can actively monitor and control both the infrared wave output of the heated backdrop and any thermal fluctuations in the test enclosure.An optional mirror array and angled heater plate can be used to control the IR wave flux to visualize the areas behind the cell casing's fill port. The leak detection algorithm used to analyze the infrared images of the prismatic cell can exhibit high tolerance to variations in cell position, gas pressure, background temperature, and atmospheric turbulence.

[0010] A representative intelligent test system and method may employ six automated techniques for detecting leaks in prismatic battery cells: (1) A temperature-controlled shield is positioned at a fixed distance from an OGI camera, while a programmable logic controller (PLC) (a) uses a temperature sensor attached to the front bottom edge of the shield to monitor and control the ambient temperature, and (b) uses the OGI camera to ensure a minimal temperature gradient within the test enclosure before initiating cell analysis; (2) Upon arrival of a battery cell within the test enclosure, (a) an evacuation and fill tube is lowered into contact with and sealed to the cell, and (b) an optional background-plus-mirror assembly is simultaneously positioned adjacent to a fill port of the cell casing;(3) the PLC initiates and controls an evacuation cycle using a vacuum pump, a pressure sensor, and an on / off relay; (4) the PLC initiates a filling routine and (a) opens a flow control valve to admit CO2 into the cell until a desired pressure is reached, and (b) once the pressure is reached, the flow control valve is closed; (5) the PLC activates the OGI camera and simultaneously starts a leak detection algorithm to detect the presence and location of leaks, including leaks that may be behind the filler neck, e.g., using the mirror; and (6) the evacuation and fill tube and the background-plus-mirror assembly are retracted before the cell proceeds to the next station.

[0011] Aspects of this disclosure relate to test system control protocols, system control logic, and instructions stored in memory that enable automatic inline leak detection for electrochemical devices. In one example, a method is presented for detecting a leak in an electrochemical device, such as CO2 gas leaks in the cell casing of a prismatic battery cell. This representative method includes, in any order and in any combination with any of the options and features disclosed above and below: positioning, e.g., via a servomotor-controlled guide cylinder, a temperature-controlled (TC) shield with an electrothermal device at a predefined distance from an infrared camera to define a test envelope therebetween; instructing, e.g.,via a stationary or remote control unit, logical device, module, or network of control units / modules / devices (collectively, "Control Unit"), the electrothermal device to increase / decrease (modify) the operating temperature of the TC shield to a predefined shield test temperature; positioning, e.g., via a conveyor system, an electrochemical device within the test enclosure located between the TC shield and the infrared camera; capturing, e.g., using the infrared camera and process PC memory, one or more infrared images of the electrochemical device within the test enclosure, showing the device enclosure positioned in front of the heat-generating TC shield; and analyzing, e.g., via the system control unit using an image analysis module, the captured infrared image(s) of the electrochemical device to determine whether a gas leak is present in the device enclosure.

[0012] Aspects of this disclosure also relate to computer-readable media (CRM) containing control device-executable instructions that enable automatic inline leak detection for electrochemical devices. In one example, a non-transitory CRM stores instructions that can be executed by one or more processors of a system control device (e.g., PLC, process PC, and digital temperature controller) of a leak detection system for detecting a leak in an electrochemical device. The electrochemical device (e.g., a prismatic lithium-class battery cell) includes a device housing (e.g., an insulated metal cell casing) with a fill opening (e.g., a cell head fill nozzle).The CRM-stored instructions, when executed by the processor(s), cause the system controller to perform operations including: instructing a shield mover to position a temperature-controlled shield having an electrothermal device at a predefined distance from an infrared camera to define a test enclosure therebetween; instructing the electrothermal device to increase a shield operating temperature of the TC shield to a predefined shield test temperature; confirming that the electrochemical device is positioned within the test enclosure between the TC shield and the infrared camera; capturing, using the infrared camera, an infrared image of the electrochemical device within the test enclosure showing the device enclosure disposed in front of the TC shield; and analyzing the captured infrared image of the electrochemical device to determine if a gas leak exists within the device enclosure.

[0013] Further aspects of this disclosure relate to automated in-line leak detection systems for detecting gas leaks in electrochemical devices, such as prismatic battery cells for vehicle battery packs. As used herein, the terms "vehicle" and "motor vehicle" may be used interchangeably and synonymously and include all relevant vehicle platforms, such as passenger cars, commercial vehicles, industrial vehicles, off-road vehicles, motorcycles, agricultural equipment, watercraft, aircraft, spacecraft, etc. For non-automotive applications, the disclosed concepts may be implemented for any logically relevant application, including portable power plants, photovoltaic systems, pumping facilities, wind turbine farms, server systems, etc. In one example, a leak detection system includes a standalone or in-line test fixture and an infrared camera fixedly mounted to the test fixture.A TC shield, which contains an electrothermal device attached to a heat-conducting plate, is movably mounted on the test fixture near the infrared camera via a shield mover automated by a control unit. A system control unit is connected to the electrothermal device, the shield mover, and the infrared camera via a wired or wireless connection.

[0014] Continuing the previous example, the system controller is programmed to instruct the shield mover to position the TC shield at a predefined distance from the infrared camera to define a test envelope between them. Before, simultaneously with, or after positioning the TC shield, the system controller instructs the electrothermal device to raise the operating temperature of the TC shield to a predefined shield test temperature. The system controller also confirms that the electrochemical device is positioned in the test envelope, which is located between the TC shield and the infrared camera. After confirmation, the controller instructs the infrared camera to take one or more infrared images of the electrochemical device in the test envelope, showing the device housing and fill port located in front of the TC shield.The system control unit then analyzes the captured infrared image(s) to identify any gas leak in the electrochemical device enclosure.

[0015] In each of the disclosed systems, methods, and CRMs, the leak detection system controller may communicate with a temperature sensor attached to the TC shield to receive sensor signals indicative of a real-time operating temperature of the TC shield. In this case, the system controller may instruct the electrothermal device to actively modulate the operating temperature of the TC shield based on the real-time sensed operating temperature of the TC shield. In at least some system configurations, the temperature sensor may be attached to a bottom edge of a front surface of the TC shield facing the camera. According to the invention, the system controller uses the infrared camera to monitor a temperature gradient within the test enclosure.In this case, the system control unit instructs the electrothermal device to actively modulate the operating temperature of the TC shield to thereby maintain the temperature gradient at a gradient value less than or equal to a predefined maximum allowable temperature gradient.

[0016] In all disclosed systems, methods, and CRMs, the system controller can instruct a hydraulic, pneumatic, or electromechanical linear press to bring an evacuation and fill tube into contact with the fill opening of the device enclosure after the electrochemical device has been positioned in the test enclosure. In this case, the system controller can instruct the linear press to seal the evacuation and fill tube to the fill opening (e.g., by generating a predefined contact pressure between the tube and the opening). A fluid pump automated by a control unit can be fluidly coupled to the evacuation and fill tube via an electronic flow control valve. After the evacuation and fill tube is sealed to the fill opening, the system controller can instruct the fluid pump to evacuate gas from the device enclosure through the fill opening to create a predefined vacuum pressure in the device enclosure.After the fluid pump has evacuated gas from the device enclosure, the system control unit can instruct the flow control valve to open, thereby directing pressurized gas through the evacuation and fill tube and the fill port into the device enclosure. The flow control valve can be a three-way, multiport electronic pressure center valve that fluidly couples the fluid pump and a pressurized gas cylinder to the tube.

[0017] For each of the disclosed systems, methods, and CRMs, a mirror assembly can be positioned between the fill port of the device housing and a selected portion of the TC screen. In this case, the mirror assembly can be rigidly attached to the TC screen and therefore move with it. As another option, the analysis of the acquired infrared images from the electrochemical device can first involve evaluating the imaged MWIR waves generated by the electrothermal device and passing between the TC screen and the device housing. The system controller then locates any aberrations within the imaged MWIR waves; any aberration is caused by compressed gas leaking from the device housing.In at least some system configurations, the TC shield includes a U-shaped plate assembly with a metallic center plate and a pair of metallic flaps, each extending orthogonally from an opposite edge of the metallic center plate. In this case, the electrothermal device may be a silicone rubber heating pad bonded, for example, to the center plate and metallic flaps via a thermally conductive pressure-sensitive adhesive (PSA), so that the MWIR waves generated by the electrothermal device travel from the silicone rubber heating pad through the metallic plate / flaps and across the device enclosure. An airflow-restricting cover (e.g., an open-bottom Plexiglas jar) may be placed around the TC shield and electrochemical device to regulate the flow around the device during testing. Fig. 1 is a partially schematic side view illustration of a representative motor vehicle powered by an electrified powertrain and supplied by a battery pack including rechargeable battery cells with which aspects of this disclosure may be practiced. Fig. Figure 2 is a schematic diagram of a representative electrochemical device with which aspects of this disclosure may be practiced. Fig. 3 is a schematic illustration of a representative battery cell testing system and method for automating in-line gas leak detection of prismatic battery cells in accordance with aspects of the present disclosure. Fig. 4-8 are flowcharts illustrating a representative test system control protocol for in-line automation of leak detection in electrochemical devices, which, in accordance with aspects of the disclosed concepts, may correspond to instructions stored in memory that may be executed by a fixed or remote microcontroller, programmable logic controller, control module, or other integrated circuit (IC) or network of circuits / modules / microcontrollers / IC devices (collectively, "System Controller").

[0018] With reference to the drawings, in which like reference numerals refer to like features in the several views, Fig. 1, a representative motor vehicle is illustrated, generally designated 10, and shown for discussion as an electrically powered sedan-style automobile. The depicted motor vehicle 10—also referred to herein as a "motor vehicle" or "vehicle" for short—is merely an exemplary application with which aspects of this disclosure may be practiced. Likewise, the incorporation of the present concepts into the illustrated battery testing system for detecting leaks in lithium-class prismatic battery cells should be recognized as a non-limiting implementation of the disclosed features. It should be understood that aspects and features of this disclosure may be incorporated into other test system architectures, may be used for testing any logically relevant type of electrochemical device, and may be employed for both automotive and non-automotive applications.Furthermore, only selected components of the motor vehicle, test system, and battery cell are shown and described in detail herein. Nevertheless, the vehicles, systems, and cells discussed below may incorporate numerous additional and alternative features, as well as other available peripheral hardware, to perform the various methods and functions of this disclosure.

[0019] The representative vehicle 10 of Fig. 1 is originally equipped with a vehicle telecommunications and information unit (“telematics”) 14 that communicates wirelessly, e.g., via a cellular network, a satellite service, a wireless modem, etc., with a remote or “off-board” cloud computing host service 24 (e.g., OnStar®). Some of the other vehicle hardware components 16 that are included in Fig. 1 include, by way of non-limiting examples, an electronic video display device 18, a microphone 28, audio speakers 30, and various user input controls 32 (e.g., buttons, knobs, switches, joysticks, touchscreens, etc.). These hardware components 16 act, in part, as a human-machine interface (HMI), allowing the user to communicate with the telematics unit 14 and other components located both inside and outside the vehicle 10. The microphone 28, for example, provides occupants with a means of inputting verbal commands; the vehicle 10 may be equipped with embedded audio filtering, processing, and analysis modules to process the commands. Conversely, the speaker 30 provides an audible output to a vehicle occupant and may be either a standalone speaker or part of an audio system 22.The audio system 22 is operatively connected to a network connection interface 34 and an audio bus 20 to receive analog information and reproduce it as sound through one or more speaker components.

[0020] Communicatively coupled to the telematics unit 14 is a network connection interface 34, which may include, for example, fiber optic Ethernet switches, parallel / serial communication buses, LAN (local area network) interfaces, CAN (controller area network) interfaces, and the like. The network connection interface 34 enables the vehicle hardware 16 to send and receive signals with each other and with various systems inside and outside the vehicle body 12. This enables the vehicle 10 to perform various vehicle functions, such as modulating powertrain power, activating friction and regenerative braking systems, controlling vehicle steering, and other automated functions.For example, the telematics unit 14 may exchange signals with a powertrain control module (PCM) 52, an advanced driver assistance system (ADAS) module 54, an electronic battery control module (EBCM) 56, an steering control module (SCM) 58, a brake system control module (BSCM) 60, and various other control modules in the vehicle, such as a transmission control module (TCM), an engine control module (ECM), a sensor system interface module (SSIM), etc.

[0021] Further referring to Fig. 1, the telematics unit 14 is an on-board computing device that provides a range of services both individually and through its communication with other networked devices. This telematics unit 14 may generally consist of one or more processors 40, each of which may be embodied as a discrete microprocessor, an application-specific integrated circuit (ASIC), or a dedicated control unit. Vehicle 10 may provide centralized vehicle control via a central processing unit (CPU) 36 operably coupled to a real-time clock (RTC) 42 and one or more electronic storage devices 38, each of which may take the form of a CD-ROM, a magnetic disk, an integrated circuit (IC), solid-state drive (SSD), hard disk (HDD), flash memory, semiconductor memory (e.g., various types of RAM or ROM), etc.

[0022] Long-range communication (LRC) with remote devices outside the vehicle may be provided via one or more or all of a cellular phone chipset / component, a navigation and positioning chipset / component (e.g., GPS transceiver), or a wireless modem, all shown collectively at 44. Short-range wireless connectivity may be provided via a short-range communication (SRC) device 46 (e.g., a Bluetooth® unit or an NFC transceiver), a dedicated short-range communication component (DSRC) 48, and / or a dual antenna 50. The communication devices described above may enable data exchange as part of a periodic broadcast in a vehicle-to-vehicle (V2V) or vehicle-to-everything (V2X) communication system.

[0023] CPU 36 receives sensor data from one or more sensing devices using, for example, photodetection, radar, laser, ultrasonic, optical, infrared, or other suitable technology to perform a control unit-assisted automated driving (AV / ADAS) operation or vehicle navigation service. According to the example shown, vehicle 10 may be equipped with one or more digital cameras 62, one or more range sensors 64, one or more vehicle speed sensors 66, one or more vehicle dynamics sensors 68, and the necessary filtering, classification, fusion, and analysis hardware and software to process the raw sensor data. The type, placement, number, and interoperability of the distributed array of on-board sensors may be individually or collectively tailored to a particular vehicle platform to achieve a desired level of automated vehicle operation.

[0024] To drive the motor vehicle 10, an electrified drive train can generate a traction torque and deliver it to one or more of the drive wheels 26 of the vehicle. The drive train is in Fig. 1 by a rechargeable, chassis-mounted battery pack 70 operatively connected to an electric traction motor (M) 78. The traction battery pack 70 generally consists of one or more battery modules 72, each containing a group of battery cells 74, such as lithium-class or organosilicon-class cells of the pocket, prism, or cylinder type. One or more electrical machines, such as traction motor / generator (M) units 78, draw electrical energy from, and optionally supply it to, the battery pack 70. A power inverter module (PIM) 80 electrically connects the battery pack 70 to the motor(s) 78 and modulates the transfer of electrical current between them. The battery pack 70 may include an integrated electronics package, such as a wireless cell monitoring unit (CMU) 76, which enables module management, cell sensing, and module communication functions.

[0025] In Fig. 2, an exemplary electrochemical device in the form of a rechargeable lithium battery 110 is shown that can drive a desired electrical load, such as the motor 78 of Fig. 1. The battery 110 includes a series of electrically conductive electrodes, namely a first (negative or anode) working electrode 122 and a second (positive or cathode) working electrode 124, which are stacked and packaged within a protective outer casing 120 (also referred to herein as a "cell case" or "case"). Referring to either of the working electrodes 122, 124 as an "anode" or "cathode," or in this context as "positive" or "negative," does not limit the electrodes 122, 124 to a particular polarity, as the system polarity may change depending on whether the battery 110 is operating in a charge or discharge mode. The device housing 120 (also referred to herein as the “cell housing”) may take a cylindrical construction, a pocket construction, or a prismatic construction formed from aluminum, nickel-plated steel, ABS, PVC, or other suitable material.A metal casing may be coated with a polymer coating to insulate the metal from the internal cell elements and from neighboring cells. Although . Fig. 2 shows a single galvanic monocell unit enclosed within cell casing 120, it should be appreciated that casing 120 may accommodate a stack or reel of monocell units (e.g., five to 500 cells or more).

[0026] The anode electrode 122 may be fabricated with an active anode electrode material capable of trapping lithium ions during a battery charging process and releasing lithium ions during a battery discharging process. In at least some embodiments, the anode electrode 122 is fabricated in whole or in part from a lithium metal, e.g., lithium-aluminum (LiAl) alloy materials with a Li / Al atomic ratio (as indicated by an atomic percentage (at.%) of an atomic species relative to a total number of atoms) in the range of 0 at.%≤Li / Al<70 at.% and / or aluminum alloys with an Al atomic ratio >50 at.% (e.g., lithium metal is molten). Further non-limiting examples of suitable active anode materials include carbonaceous materials (e.g., graphite, hard or soft carbon, etc.), silicon, silicon-carbon mixed materials (silicon-graphite composite), Li4Ti5O 12, transition metals (alloy types, e.g. Sn), metal oxides / sulfides (e.g. SnO2, FeS and the like), etc.

[0027] The cathode electrode 124 can be fabricated with an active cathode electrode material capable of delivering lithium ions during a battery charging process and trapping lithium ions during a battery discharging process. The material of the cathode 124 can include, for example, a lithium transition metal oxide, phosphate (including olivine), or silicate, such as LiMO2 (M=Co, Ni, Mn, or combinations thereof); LiM2O4 (M=Mn, Ti, or combinations thereof), LiMPO4 (M=Fe, Mn, Co, or combinations thereof), and LiMxM'2-xO4 (M, M'=Mn, or Ni). Additional non-limiting examples of suitable active cathode materials include lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese aluminum oxide (NCMA), and other lithium transition metal oxides.

[0028] Inside the cell housing 120 of Fig. 2, and between each paired pair of working electrodes 122, 124 is an electrically insulating porous separator 126. The separator 126 may be in the form of an electrically non-conductive, ion-transporting micro- or nanoporous polymeric separator film. The separator 126 may be a film-like structure formed from a porous polyolefin membrane, e.g., with a porosity of about 35% to about 65%. Electrically non-conductive ceramic particles (e.g., silicon dioxide) may be applied to the porous membrane surfaces of the separators 126. The porous separator 126 may include a non-aqueous liquid electrolyte composition, a solid electrolyte composition, and / or a quasi-solid electrolyte composition, collectively referred to as 130, which may also be present in the negative electrode 122 and the positive electrode 124.The porous separator 126 can function as both an electrical insulator and a mechanical support structure by being inserted between the two electrodes 122, 124 to prevent the electrodes from coming into physical contact with each other and thus preventing a short circuit from occurring. In addition to providing a physical barrier between the electrodes 122, 124, the separator 126 can provide a minimal resistance path for the internal passage of lithium ions (and related anions) during lithium ion cycling to facilitate the functioning of the battery 110.

[0029] A negative electrode current collector 132 of the electrochemical battery cell 110 can be positioned at or near the negative electrode 122, and a positive electrode current collector 134 can be positioned at or near the positive electrode 124. The negative electrode current collector 132 and the positive electrode current collector 134 each collect free electrons and transport them to and from an external circuit 140. An interruptible external circuit 140 with a load 142 is connected to the negative electrode 122 via its respective current collector 132 and negative electrode tab 136, and to the positive electrode 124 via its respective current collector 134 and positive electrode tab 138.

[0030] As a rechargeable storage device, battery 110 generates electrical power that is transferred to one or more operational electrical loads 142 connected to external electrical circuit 140. Load 142 may be any number of devices. Some non-limiting examples of power-consuming devices include electric traction motors for hybrid and all-electric vehicles, photovoltaic systems, autonomous power plants and portable power generators, server systems, wind turbines, etc. Battery cell 110 may include a variety of other components, such as fluid seals, terminal caps, cell heads, tabs, battery posts, cooling and charging devices, and other commercially available components that may be located on or within battery 110. Furthermore, the size and shape, as well as the operating characteristics, of battery 110 may vary depending on the specific application for which it is intended.

[0031] Fig. 3 schematically illustrates a non-limiting example of a battery cell test system 200 for automating in-line gas leak detection in prismatic battery cells. In accordance with the illustrated example, the test system 200 consists of six interoperable subsystems: (1) a standalone test fixture subsystem 202; (2) a high-precision linear press subsystem 204; (3) a pump-assisted evacuation subsystem 206; (4) a pressurized gas delivery subsystem 208; (5) a system controller network 210; and (6) a cell conveying subsystem 212. Although not limited per se, the test fixture 202 may be Fig. 3, a rigid support platform 214 having a pair (first and second) support posts 216 and 218, each fixedly mounted on the support platform 214 and projecting vertically upward therefrom. A temperature-controlled (TC) shield 220 is movably mounted on the upper end of the left (first) support post 216 via a servo-motor-controlled guide cylinder 222. Opposing the TC shield 220 is an optical infrared gas imaging (OGI) camera 224 (e.g., a medium-sized FLIR optical sensor capturing 10-200 frames per second (fps)), which is pivotally mounted on the upper end of the right (second) support post 218 via a rotatable mount 226. It is envisaged that the battery cell test system 200 may adopt different architectures, may include more or fewer than six interoperable subsystems, and may use similar or different subsystem types than those shown in the figures.

[0032] To enable active thermal control of the test procedure, the TC-shield 220 from Fig. 3 shows a U-shaped plate assembly generally characterized by a thermally conductive (metallic) center plate 228 having a pair of thermally conductive (first and second metallic) flaps 230, each extending orthogonally from a respective opposite (first or second) edge of the center plate 228. The center plate 228 and the adjacent flaps 230 may be made from individual anodized aluminum plates joined together, for example, by welding or clamping; alternatively, the center plate 228 and the adjacent flaps 230 may be formed as a one-piece structure from a single anodized aluminum plate. An electrothermal device 232, which may act as a silicone rubber heating pad, is used, for example, B. glued to the backs of the center plate 228 and the adjacent flaps 230 with a thermally conductive pressure sensitive adhesive (PSA) or an epoxy-based thermal interface material (TIM) adhesive.A temperature sensor, such as a laser-based digital infrared sensor head 234, is operatively mounted on the TC shield 220 (e.g., on a lower edge of a front surface of the center plate 228 facing the camera). The temperature sensor 234 senses a real-time operating temperature of the TC shield 220 and outputs temperature sensor signals indicative thereof to a programmable logic controller (PLC) of the system 236. With this arrangement, the PLC 236 portion of the system controller 210 network can control the heating power of the electrothermal device 232 to actively modulate the operating temperature of the TC shield based on the real-time sensed operating temperature of the TC shield 220.

[0033] With further reference to Fig. 3, the high-precision linear press 204 can be mounted on the test fixture 202 on top of the deployable TC screen 220. The linear press 204 can be a one-kilonewton (kN) hydraulic, pneumatic, or electromechanical press with force and / or displacement feedback. An evacuation and fill tube 238 and a vacuum pressure sensor 240 are attached to a distal (lower) end of a linearly displaceable piston 242, which is operable to bring the evacuation and fill tube 238 into contact with a fill opening 244 in the head of a device housing 246 of an electrochemical device 248. Although different in appearance, the electrochemical device 248 can be Fig. 3 have all the features and options described above with respect to the rechargeable lithium battery 110 of Fig. 2. With this arrangement, the PLC 236 portion of the system controller 210 network may activate the linear press 204 to align, abut, and seal the evacuation and fill tube 238 against the fill opening 244 (e.g., by applying at least five (5) pounds (lbs.) of pressure via the tube 238 to the fill opening 244 to create a fluid-tight seal).

[0034] To enable controlled pressurization of the electrochemical device 248, the pump-assisted evacuation subsystem 206 utilizes a controller-automated fluid pump 250 fluidly coupled to the evacuation / fill tube 238 via an electronic flow control valve 252. According to the illustrated example, the flow control valve 252 is a three-way, five-port electronic pressure center valve. Once the evacuation and fill tube 238 is sealed to the fill port 244 of the device housing, the PLC 236 of the system controller 210 may instruct the flow control valve 252 to open an outlet port 251 connecting the evacuation and fill tube 238 to the fluid pump 250, which may be a controlled electronic vacuum pump activated by an ON / OFF relay switch.The PLC 236 may simultaneously activate the fluid pump 250 to selectively evacuate gas from the device housing 246 through the fill port 244 to create a predefined vacuum pressure within the housing 246. When the device housing 246 reaches the desired vacuum level, the controller 236 may instruct the flow control valve 252 to close the outlet port 251, thereby decoupling the fluid pump 250 from the evacuation / full pipe 238.

[0035] Upon completion of the evacuation procedure, the compressed gas supply subsystem 208 uses a compressed gas container 254 and a gas conditioning device 256 to supply compressed gas through the flow control valve 252 and the evacuation and fill tube 238 into the device housing 246. As shown, the compressed gas container 254 is an aluminum alloy CO2 tank pressurized, e.g., to at least 1 pound per square inch (psi), and is fluidly coupled to an inlet port 253 of the flow control valve 252 via the gas conditioning device (CO2 conditioning) 256, with the container 254 in fluid communication upstream of the device 256.After the fluid pump 250 has evacuated the gas from the device housing 246, the PLC 236 portion of the system controller 210 can instruct the flow control valve 252 to open the fill port 253, thereby connecting the pressurized gas container 254 and the CO2 processing device 256 to the fill port 244 via the evacuation and fill tube 238. Once fluid communication is established, the container 254 directs the pressurized CO2 through the evacuation and fill tube 238 and the fill port 244 into the device housing 246. When the device housing 246 is filled with a desired volume of pressurized gas, the PLC 236 can instruct the flow control valve 252 to close the inlet port 253, thereby fluidly decoupling the container 254 from the tube 238.

[0036] Automatic control of the battery cell testing system 200 is provided by the network of the system controller 210, which may consist of the PLC 236, a process server-class computer (PC) 258, and a digital temperature controller 260. An image acquisition module 262 resident in the PC 258 is operatively connected to the OGI camera 224 via a first network interface controller 264 and controls the operation of the camera 224. Similarly, the image acquisition module 262 and an image analysis module 266 located in the PC 258 are communicatively connected to the PLC 236 via a second network interface controller 268. The image analysis module 266 analyzes the captured infrared images of the electrochemical device 248 to determine if a gas leak is present in the device enclosure 246.Both the image acquisition module 262 and the image analysis module 266 are communicatively connected to a server system database 270 located on the PC computer 258. The cell conveying system 212 may be a modular, motorized belt or roller conveyor system that automates the transfer of each electrochemical device 248 into and out of a test enclosure defined between the TC screen 220 and the OGI camera 224.

[0037] With reference to the flowcharts in the Fig. 4 to 8, in accordance with aspects of the present disclosure, at 300 an improved method or control protocol for controlling the operation of an intelligent test system, such as the battery cell test system 200 of Fig. 3, for providing automatic leak detection of an electrochemical device, such as the prismatic batteries 110 and 200 of Fig. 2 and Fig. 3, generally described. Some or all of the Fig. 4 to 8 and described in more detail below may represent an algorithm corresponding to non-transitory, processor-executable instructions stored, for example, in main or auxiliary memory or in remote memory (e.g., in the resident test system database 270 of Fig. 3 and / or the remote cloud computing database 24 of Fig. 1). These instructions may be issued, for example, by an electronic control unit, a processing unit, a dedicated control module, a logic circuit, or another module or device, or a network of control units / modules / devices (e.g., the system control unit 210 network of Fig. 3 and / or the cloud computing service 24 of Fig. 1) to perform any or all of the functions described above and below associated with the disclosed concepts. It should be noted that the order of execution of the illustrated operation blocks may be changed, additional operation blocks may be added, and some of the operations described herein may be modified, combined, or eliminated.

[0038] The method 300 begins at start terminal block 301 of Fig. 4 with processor-executable instructions stored in memory for initializing an automatic in-line gas leak detection protocol. Terminal block 301 may be initialized in response to a user command prompt (e.g., via the input controls of PC computer 258), in response to a system controller request (e.g., from PLC 236), in response to a sensor signal indicating that a new battery cell has entered the test enclosure, and / or automatically in response to system power being turned on. Upon completion of some or all of the Fig. 4-8, the method 300 may advance to terminal block 327 and temporarily terminate, or it may optionally loop back to the START terminal block 301 and run in a continuous loop.

[0039] Proceeding from terminal block 301 to SYSTEM OPERATING TEMPERATURE decision block 303, method 300 determines whether or not the test enclosure TEI between the TC shield 220 and the OGI camera 224 has reached a predefined system / shield operating temperature. In accordance with the Fig. 3, the PLC 236 may instruct the servomotor-controlled guide cylinder 222 (also referred to herein as the "shield mover") to position the TC shield 220 assembly at a predefined distance from the camera 224 to define a test envelope TEI therebetween. Once properly positioned, the PLC 236 may activate and control the electrothermal device 232 to increase and / or decrease ("modify") the operating temperature of the TC shield 220 assembly to achieve a predefined shield test temperature (e.g., between about 100 and about 180 degrees Fahrenheit (°F)). To monitor and control thermal changes of the TC shield 220, the PLC 236 communicates with the shield-mounted temperature sensor 234 to receive sensor signals therefrom that indicate a real-time operating temperature of the TC shield 220 assembly.The PLC 236 can instruct the electrothermal device 232 to actively modulate the operating temperature of the TC shield based on the real-time sensed operating temperature of the TC shield 220. Simultaneously, the PLC 236 can communicate with the OGI camera 224 via the PC computer 258 to track a temperature gradient across the test envelope TEI. The PLC 236 can instruct the electrothermal device 232 to modulate the operating temperature of the TC shield, thereby controlling the temperature gradient and ensuring that the gradient value is less than or equal to a maximum allowable temperature gradient (e.g., Δ). G ≤ 70°F).

[0040] If the predefined operating temperature has not yet been reached (block 303=NO), the process 300 may run in a continuous loop until the test system / TC shield has reached the desired operating temperature. When the predefined operating temperature is reached (block 303=YES), the process 300 may operatively proceed to process block 305, TEST INITIALIZATION, and activate the leak test. At this point, the PLC 236 may instruct the cell conveying system 212 to transport an electrochemical device 248 into the test enclosure TEI for subsequent testing. In system configurations where the conveying system 212 operates independently, the PLC 236 may communicate with a proximity sensor or similarly suitable sensing device to confirm that an electrochemical device 248 is positioned within the test enclosure TEI.

[0041] The method 300 starts from the method block 305 of Fig. 4 to decision block CELL EVACUATION 307 from Fig. 5 to determine whether the device 248 under test should be evacuated (e.g., because there is insufficient internal space for compressed CO2 to achieve a desired vessel pressure). If the device 248 in question should not be evacuated (block 307=NO), the process 300 can skip process blocks 309, 311, 313, and 315 and proceed directly to the gas filling protocol of Fig. 6. After determining that the device under test 248 is to be evacuated within the test enclosure TEI (block 307=YES), the PLC 236 may instruct the linear press 204 to align the evacuation and fill tube 238 and immerse it into contact with the fill opening 244 of the device housing 246. Once correctly aligned, the PLC 236 instructs the linear press 204 to seal the evacuation and fill tube 238 to the fill opening 244, e.g., by sealing the device housing 246 with a sealant. B. by generating a predefined contact pressure between the tube 238 and the fill opening 244. After the evacuation and fill tube 238 is fluidically closed to the fill opening 244, the method 300 executes the EVAC PROTOCOL block 309, in which the PLC 236 instructs the flow control valve 252 to fluidically connect the fluid pump 250 to the evacuation and fill tube 238 and simultaneously activates the pump 250 to suck air out of the housing 246.

[0042] After completing an evacuation cycle at process block 309, process 300 executes the VACUUM LEVEL decision block 311 of Fig. 5 to determine if a desired vacuum level has been achieved. As a non-limiting example, the PLC 236 may communicate with the vacuum pressure sensor 240, which is operatively connected to the evacuation and fill tube 238, to ensure that a sufficient amount of gas has been evacuated from the device housing 246 through the fill port 244 to achieve a predefined internal vacuum pressure. If this is not the case (block 311=NO), the method 300 may proceed in a continuous flow through blocks 309 and 311 until the desired vacuum level is achieved. Upon confirming that the desired vacuum level has been achieved (block 311=YES), the method 300 may responsively execute method block 313 PUMP OFF and deactivate the fluid pump 250.Concurrently with process block 313, process 300 may execute process block 315 VALVE SWITCH - FILL 1, in which PLC 236 instructs valve 252 to both disconnect pump 250 from evacuation and fill tube 238 and connect container 254 to evacuation and fill tube 238.

[0043] The method 300 proceeds from method block 315 of Fig. 5 to decision block EVACUATED CELL 317 of Fig. 6 to determine whether the device 248 under test has been evacuated. If it is determined that the device 248 in question has not been evacuated and should be evacuated, e.g., as described in the previous paragraph (block 317=NO), the method 300 may run in an endless loop, e.g., returning to the cell evacuation protocol of Fig. 4, until it is determined that the device 248 in question has been evacuated. After confirming that the device 248 in question has been evacuated (block 317=YES), the method 300 may respond by executing the VALVE FILL decision block 319 to determine whether or not the electronic flow control valve 252 is in a fill mode in which the valve 252 fluidly connects the pressurized gas container 254 to the evacuation and fill tube 238 and therefore to the electrochemical device 248. If not (block 319=NO), the method 300 may respond by executing the VALVE SWITCH - FILL 2 process block 321 and instructing the flow control valve 252 to fluidly connect the container 254 to the evacuation and fill tube 238. It is intended that process blocks 317, 319 and 321 may be considered optional in view of the processes presented in process blocks 307 and 315.

[0044] The method 300, after confirming that the flow control valve 252 is set to the fill mode (block 319=YES), may respond by executing the LEAK DETECTION subroutine block 323 to determine whether or not a leak exists in the device housing 246 of the particular electrochemical device 248 currently located within the test enclosure TEI. At this time, the image acquisition module 262, located in the PC computer 258 portion of the system controller 210 network, may activate and control the control operation of the OGI camera 224 to capture one or more infrared images of the particular device 248. It may be desirable for each captured infrared image to show the fill port 244 and / or the device housing 246 located in front of the heated TC shield assembly 220.Before analysis, the infrared images can be filtered, preprocessed, smoothed, compressed and stored in the database of the server system 270.

[0045] After capturing and, if desired, storing MWIR (Middle Wavelength Infrared) images of the device 248 in question, the image analysis module 266, located in the PC computer 258, analyzes the captured infrared images to determine whether or not a gas leak exists in the device housing 246. As a non-limiting example, the image analysis module 266 examines each captured infrared image to evaluate the imaged MWIR waves generated by the electrothermal device 232 that travel between the TC shield 220 and the device housing 246, e.g., along an upper trailing edge of the housing 246. The image analysis module 266 uses a gas cloud modeling algorithm to then locate one or more aberrations within these imaged MWIR waves; it can be determined that any aberration is caused by compressed CO2 gas leaking from the device housing 246 (e.g.due to a torn O-ring seal of the filler opening 244). In at least some applications, an optional mirror assembly 274 (. Fig. 3) be placed between the fill port 244 of the device housing and one of the adjacent flaps 230 of the TC shield assembly 220. It may be desirable for the mirror assembly 274 to be rigidly connected to the TC shield assembly 220 and therefore move in unison with it. The mirror assembly 274 may help redirect MWIR waves to enhance the analysis of the respective electrochemical device 248 for leak detection. Upon completion of the leak detection analysis at block 323, the method 300 may execute the process block 325 VALVE SWITCH - EVAC1, in which the PLC 236 instructs the flow control valve 252 to switch back to an evacuation mode; the method 300 then returns to the process block 307 of Fig. 5 to evaluate another electrochemical device. Alternatively, the method may instruct the PLC 236 to switch the flow control valve 252 to a closed mode; the method 300 may then proceed to the END terminal block 327 and temporarily terminate.

[0046] In connection with the various Fig. 4-6 and described above, the network of the system controller 210 can be Fig. 3, including PLC 236, PC computer 258 and digital temperature controller 260, which are Fig. 7 and Fig. 8. For example, PLC 236 may initialize the gas leak detection protocol connected to START terminal block 301 upon detection of one or more prismatic battery cells 248 arriving at the station of battery testing system 200, as shown in Fig. 7 is displayed in CELL PALLET DETECTION process block 329. Upon detection of a new pallet of battery cells, process 300 may responsively execute PALLET SCAN process block 331; at this time, the PLC may read an RFID tag, NFC transponder, QR code, or similarly suitable data device to retrieve information about the prismatic battery cells on the new pallet. Based on the retrieved data, PLC 236 may determine at CELL REJECT decision block 333 whether the cell or cells on the pallet are not designated as "reject." If the pallet cell(s) are designated as reject (block 333=NO), PLC 236 may responsively execute DROP PALLET-1 process block 335 to stop and release the new pallet; At this point, the process 300 may return to process block 329 and await the arrival of a new pallet.

[0047] If it is determined that the pallet cell(s) has / have not been designated as scrap (block 333=YES), PLC 236 may respond by executing process block 337 PALLET POSITIONING to lift and position the pallet, e.g., for sequentially feeding the individual battery cells into the test fixture 202 via the conveyor subsystem 212. At process block 339 FILL TUBE, PLC 236 may instruct linear press 204 to lower evacuation and fill tube 238 into contact with fill port 244 of each cell 248 being inspected for gas leaks. The PLC 236 may then execute the NOZZLE SEAL process block 341 and instruct the linear press 204 to apply a predefined pressure (e.g., 5 lbs) via the evacuation and fill tube 238 to the fill nozzle 244 to create a fluid seal therebetween.Once the evacuation and fill tube 238 is sealed to the fill port 244, the PLC 236 executes process block 343 VALVE SWITCH - EVAC2 and instructs the valve 252 to enter evacuation mode.

[0048] After the fluid pump 250 has been connected to the battery cell fill port 244 via the valve 252 and the evacuation and fill tube 238, the PLC 236 can execute the EVAC PROTOCOL process block 345 and turn on the fluid pump 250. At decision block 347 VACUUM ACHIEVED, the PLC 236 can determine whether the evacuated cell housing 246 has reached a desired vacuum level. If so (block 347=YES), the PLC 236 can execute the VALVE SWITCH - FILL 3 process block 349 and instruct the flow control valve 252 to switch to fill mode, thereby connecting the reservoir 254 to the evacuation and fill tube 238. PLC 236 may then execute decision block 351 FILL ACHIEVED to determine whether or not the evacuated and filled cell housing 246 has reached a desired internal gas pressure. If so (block 351=YES), process 300 may automatically proceed to block 353 of the image acquisition process of Fig. 8 progress.

[0049] With reference to Fig. 8, the PC computer 258 may execute the image capture process block 353 and, using the OGI camera 224, acquire infrared images of each cell 248 being inspected for gas leaks. Each acquired image may be saved to the database of the server system 270 or other solid-state drive (SSD) storage at WRITE TO DISC process block 355. After each image has been written to disk, the PC computer 258 may execute the SAVED IMAGE decision block 357 to determine if each image was properly saved. If so (block 357=YES), the PC computer 258 may responsively execute the LOAD IMAGE process block 359, PROCESS IMAGE process block 361, and WRITE IMAGE process block 363 in sequence to load, process, and save each processed image, respectively. Process blocks 357, 359, 361 and 363 can be executed for each infrared image taken.

[0050] The method 300 may proceed from the WRITE TO DISC method block 355 to the TIME LAPSE method block 365 of Fig.8, in which the PC computer 258 can determine if a preset image acquisition window (e.g., approximately five (5) seconds) has elapsed. If this has not been the case (block 365=NO), the method 300 can return to process block 353 and acquire additional infrared images of the respective cell 248. If it is determined that the preset image acquisition window has expired (block 365=YES), the PC computer 258 can respond by executing process block 367, STOP ACQUISITION, and instructing the OGI camera 224 to temporarily cease image acquisition. Depending on the results of the leak detection analysis for each battery cell 248 evaluated, the PC computer 258 can write PASS or FAIL to the pallet's RFID tag / data device at ANALYSIS RESULTS (process block 369).The PC computer 258 may then execute the DROP PALLET-2 process block 371 to release the evaluated pallet; at this time, the process 300 may loop back to the process block 329 and await the arrival of a new pallet or proceed to the END terminal block 327.

Claims

[1] A method (300) for detecting a leak in an electrochemical device (248), the electrochemical device comprising a device housing (246) having a fill opening (244), the method (300) comprising: Positioning (301) a temperature-controlled shield (220) with an electrothermal device (232) at a predefined distance from an infrared camera (224) to define a test envelope (TE1) therebetween; instructing (303) the electrothermal device (232) via a system controller (210) to change a shield operating temperature of the temperature-controlled shield (220) to a predefined shield test temperature; Positioning (305) the electrochemical device (248) in the test enclosure (TE1) between the temperature-controlled shield (220) and the infrared camera (224); Taking (353) an infrared image of the electrochemical device (248) in the test enclosure (TE1) using the infrared camera (224), showing the device housing (246) positioned in front of the temperature-controlled shield (220); Analyzing (323) the captured infrared image of the electrochemical device (248) via the system control unit (210) to determine whether a gas leak is present in the device housing (246), Monitoring a temperature gradient across the test envelope (TE1) by the system controller (210) using the infrared camera (224); and Instructing the electrothermal device (232) via the system controller (210) to modulate the operating temperature of the temperature-controlled shield (220) to thereby maintain the temperature gradient at a gradient value less than or equal to a maximum allowable temperature gradient. [2] The method (300) of claim 1, further comprising: Receiving (303) sensor signals indicative of a real-time operating temperature of the temperature-controlled screen (220) via the system controller (210) from a temperature sensor (234) attached to the temperature-controlled screen (220); and Instructing (303) the electrothermal device (232) via the system controller (210) to modulate the operating temperature of the shield (220) depending on the real-time operating temperature of the temperature-controlled shield (220). [3] The method (300) of claim 2, wherein the temperature sensor (234) is mounted on a lower edge of a front surface of the temperature-controlled screen (220) facing the camera (224). [4] The method (300) of claim 1, further comprising: Instructing (307), via the system control unit (210), after the electrochemical device (248) is positioned in the test enclosure (TE1), a linear press (204) to move an evacuation and fill tube (238) into contact with the fill opening (244) of the device housing (246); and instructing, via the system control unit (210), the linear press (204) to close (307) the evacuation and fill tube (238) to the fill opening (244), wherein the evacuation and fill tube (238) is coupled in fluid communication with a fluid pump (250). [5] The method (300) of claim 4, further comprising instructing the fluid pump (250) via the system controller (210), after the evacuation and filling tube (238) is sealed to the fill opening (244), to evacuate gas from the device housing (246) through the fill opening (244) to create a predefined vacuum pressure in the device housing (246) (309). [6] The method (300) of claim 5, further comprising instructing (315) a flow control valve (252) via the system controller (210) after the fluid pump (250) has evacuated the gas from the device housing (246) to open and thereby direct pressurized gas through the evacuation and fill tube (238) and the fill opening (244) into the device housing (246). [7] The method (300) of claim 6, wherein the flow control valve (252) includes a three-way multiport pressure central valve coupling the fluid pump (250) and a pressurized gas container (254) in fluid communication with the evacuation and fill tube (238). [8] The method (300) of claim 1, further comprising positioning a mirror assembly (274) between the fill opening (244) of the device housing (246) and a selected portion of the temperature-controlled shield (220). [9] The method (300) of claim 1, wherein analyzing the captured infrared image includes: Evaluating the imaged medium wavelength infrared (MWIR) waves generated by the electrothermal device (232) and passing between the temperature-controlled screen (220) and the device housing (246); and Localize an aberration in the imaged MWIR waves caused by compressed gas leaking from the electrochemical device (248).

Images