Dilution and sampling of sealed battery waste

Abstract

A sealed battery discharge dilution and sampling system includes a heated exhaust pipe, a housing having at least one inlet port defined at one end and an outlet port communicating with the heated exhaust pipe at the other end, a dilution air line, at least one heated inlet line disposed with one end of the dilution air line and communicating with the at least one inlet port, and a bypass line connected between the dilution air line and the heated exhaust pipe and disposed around the housing.

Description

Technical Field

[0001] (Cross-Reference to Related Application) This application claims priority to U.S. Patent Application No. 18 / 452,131 filed on August 18, 2023, the disclosure of which is incorporated into the present application by reference.

[0002] The present disclosure relates to battery inspection equipment. Background Art

[0003] Proper sampling is crucial for measuring emissions from batteries (cells, modules, packs, etc.).

[0004] Gas chromatography-mass spectrometers can detect and identify trace amounts of volatile organic compounds and other gases released from batteries.

[0005] Differential scanning calorimeters can measure the heat flow of a battery during operation, thereby enabling identification of exothermic reactions that may lead to thermal runaway and the energy released during the thermal runaway phase.

[0006] Fourier transform infrared spectrometers can identify specific chemical bonds and functional groups present in emissions from batteries.

[0007] Some battery emission inspection devices feature real-time monitoring. Sensors can provide continuous data regarding temperature, gas concentration and other parameters during battery operation.

[0008] Some battery emission inspection devices incorporate a housing that can prevent leakage of energy, emissions and debris during thermal runaway.

[0009] Devices and controls for initiating battery thermal runaway include nail penetration, controlled heating pads, and electrical connections for initiating overcharge / overvoltage. [Overview of the project]

[0010] A sealed battery exhaust dilution and sampling system comprises a heated exhaust pipe, a housing that completely encloses the battery and has at least one inlet port at one end and an outlet port at the other end communicating with the heated exhaust pipe, a dilution air line, at least one heated inlet line disposed with one end of the dilution air line and communicating with at least one inlet port, and a bypass line connected between the dilution air line and the heated exhaust pipe and disposed around the housing. The system further includes a pump disposed to flow a portion of the dilution air from the dilution air line into the housing on the at least one heated inlet line and the battery, to take in the battery exhaust into the housing to generate a diluted sample gas which is then discharged to the outlet port, to flow the remainder of the dilution air into the bypass line around the housing, and to mix the diluted sample gas and the remainder of the dilution air in the heated exhaust pipe. The system further includes a controller that calculates the mass flow rate of the exhaust as the difference between the mass flow rate of the gas through the heated exhaust pipe and the mass flow rate of the gas through the dilution air line. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of the layout for inspecting discharges from sealed batteries. [Modes for carrying out the invention]

[0012] Embodiments are described below. However, it should be understood that the disclosed embodiments are merely illustrative and that other embodiments may take various alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or minimized in order to show the details of certain parts. Accordingly, the specific structural and functional details disclosed herein should not be construed as limiting but merely as representative grounds for teaching to those skilled in the art.

[0013] By combining various features illustrated or described, embodiments not explicitly illustrated or described can be generated. The illustrated feature combinations represent typical embodiments for typical uses. However, for specific uses or implementations, various combinations and modifications of features consistent with the teachings of this disclosure may be desirable.

[0014] A lithium-ion battery typically includes a positive electrode (cathode), a negative electrode (anode), an electrolyte, and a separator. The electrodes may be made of a material that inserts (absorbs) and deinserts lithium ions during the charge and discharge cycle. The electrolyte facilitates the movement of lithium ions between the electrodes, while the separator prevents the movement of electrons through the electrolyte. This allows electrons to pass through the external circuit, generating an electric current.

[0015] During normal operation, lithium ions move between the cathode and anode via the electrolyte, generating thermal energy. This energy is directly proportional to the current. If the battery experiences an internal short circuit, a large amount of current and heat will be generated. If the battery experiences rapid heating due to external punctures or internal short circuits (such as thermal runaway), several chemical reactions can be triggered that lead to the generation of waste products.

[0016] The electrolyte in lithium-ion batteries is typically a lithium salt dissolved in a solvent. At high temperatures, the electrolyte can decompose, releasing gases such as carbon dioxide, carbon monoxide, and volatile organic compounds. This failure occurs due to the thermal degradation of the solvent and lithium salt. In other modifications, the electrolyte may consist of a solid material. This material may be a polymer, oxide, sulfide, halide, or other composition, and the properties and composition of the corresponding emissions may vary considerably.

[0017] The cathode material in lithium-ion batteries often contains metal oxides such as lithium cobalt oxide or lithium iron phosphate. The cathode material may also contain more complex compounds such as nickel-manganese-cobalt and nickel-cobalt-aluminum. At high temperatures, these metal oxides can undergo chemical reactions that release oxygen. When oxygen reacts with other materials in the battery, it can lead to the production of gases such as carbon monoxide and carbon dioxide. The release of oxygen can also cause lithium-ion batteries to burn continuously even in the absence of external oxygen.

[0018] The anode is generally made of graphite or other carbon-based materials. Other anode materials include silicon, lithium titanate oxide, and pure lithium metal. At high temperatures, these materials can react with the electrolyte or other components, potentially releasing gases. Therefore, in some cases, the anode may undergo a process in which the anode material reacts exothermically with the lithium compound, further increasing its temperature.

[0019] Batteries may contain organic components that oxidize or decompose at high temperatures. These reactions release volatile organic compounds and other by-products, which can contribute to emissions generated during thermal runaway.

[0020] If the internal temperature of the battery rises, the casing may be damaged, potentially exposing reactive materials to the environment. This could trigger further exothermic reactions and gas generation.

[0021] The emissions generated during a thermal runaway event vary depending on numerous factors, including the battery's chemical properties, the materials used, and the specific conditions of the runaway. Therefore, batteries may be inspected to evaluate the nature of their emissions and their tendency to generate them.

[0022] Measuring battery cell emissions requires comprehensive extraction of gases emitted from the device under test (battery, cells, modules, etc.) from its enclosure. However, the device under test does not inherently generate the pressure or flow necessary to facilitate the movement of emissions to the sample analyzer. Therefore, a battery thermal runaway testing system must be capable of generating a certain flow to transport battery emissions from the device under test to the sampler.

[0023] The emissions must be extracted while the temperature of the device under test is maintained to allow the thermal runaway reaction to continue. This means that the diluting air introduced into the chamber containing the device under test must match the test temperature, which may exceed 1200°C. However, emissions analyzers may require the sample gas temperature to be even lower (e.g., below 400°C). Emissions analyzers also require that the gas in the sample be diluted to a level acceptable to the analyzer.

[0024] In some examples, a test arrangement is proposed in which dilution air is supplied through two paths. One path bypasses the chamber accommodating the device under test at ambient temperature. The other path passes through a heating element to adjust to the temperature of the device under test and flows through the chamber. Said other path may be used to purge the enclosure over a predetermined period before the onset of thermal runaway (and the onset of emissions). The bypass path may be used to obtain a baseline reading of the characteristics of dilution air before testing. During testing, a valve (such as a piezoelectric valve, a needle valve, etc.) may be used to split the dilution flow between the chamber and the bypass. The hot air passing through the chamber promotes the movement of gas released from the device under test without affecting the temperature of the device under test. The temperature of the hot air is controlled by feeding back the temperature of the chamber to the setting of the heating element for the hot air. Cold air is used downstream of the chamber to reduce the level and temperature of emissions to levels suitable for an analyzer. A valve defines the ratio between hot air and cold air to control the temperature of the emissions at the sampler depending on the temperature of the device under test.

[0025] The test arrangement may comprise a combination of an enclosure of the device under test, a supply of dilution air, and a configuration of tubes and valves coupled to the chamber. The chamber can be designed to allow airflow as required.

[0026] Prior to the start of inspection, the diluted air may be supplied around the bypass path. This is used as a reference for downstream measurements. When inspection is started, the valve is switched, and the diluted air flows through the device to be inspected (such as battery cells, packs, modules, etc.). Thereby, the exhaust from the device to be inspected passes through the required heating line path. The ratio of diluted air and the temperature of the thermally diluted air are defined by the observed temperature of the device to be inspected. The split ratio of the diluted air can be changed, for example, from 80% cold air and 20% hot air to 80% cold air and 20% hot air, at a ratio defined by the required cooling behind the housing. In some examples, the split ratio can be set using proportional-integral-derivative control based on the temperature of the gas behind the housing. If the temperature of the inspection chamber is lower than the temperature required for the analyzer, a larger amount of hot air is used. If the temperature of the chamber exceeds the maximum temperature of the analyzer, cold air may be used to reduce the overall gas temperature before it reaches the analyzer.

[0027] When inspecting batteries, accurate estimation of gas emission and real-time analysis of gas are required during battery cycling and thermal runaway events. This is particularly difficult in the case of thermal runaway, because a large amount of gas may be generated without a constant pressure for transferring the gas to other parts of the system. The use of the proposed diluted air flow through the chamber provides a constant flow and pressure for the gas to move through the system, enabling constant real-time measurement.

[0028] The approach considered also enables effective execution of thermal runaway inspection at an appropriate temperature, while keeping the gas temperature within an available range before collecting samples for the gas analyzer.

[0029] Pressure can be applied by airflow, but a vacuum approach may be used to extract the exhaust from the chamber. The direction of airflow may be varied. A vertical airflow (bottom to top) is preferred for uniform dispersion and mixing of the exhaust, but a horizontal airflow may also be used. The chamber may be cylindrical or other shapes (for uniform dispersion). To promote turbulence and mixing of the air, the method of providing the airflow may be varied (for example, using a series of small holes instead of one large hole).

[0030] Other available systems may not be able to extract effluent from the chamber with the same level of sophistication as proposed. This means there may be a delay when effluenting the gas from the chamber, which could affect the reliability of the measurements. The lack of facilitated dilution / effluent mixing also means that the concentrations of effluent / dilution may not be uniform in alternative designs, which could affect the reproducibility of the tests and could result in localized samples outside the measurement range.

[0031] Referring to Figure 1, the battery discharge inspection setup 10 includes a dilution air line 12, a filter 14, a mass flow meter 16, a bypass line 18, a valve 20, a valve 22, an inlet line 24, a heater 26, a housing 28, a tube 30, a heater 32, an analyzer 34, an analysis line 36, a valve 38, a filter 40, a mass flow meter 42, a valve 44, a pump 46, and a controller 48.

[0032] The dilution air line 12 has a filter 14 and a flow meter 16 and is in communication with the valve 22. The flow meter measures the mass flow rate Qa of the gas passing through the dilution air line 12 before it enters the valve 22.

[0033] The bypass line 18 branches off from the dilution air line 12 upstream of the valve 22 and has a valve 20. The flow rate of gas through the bypass line 18 is controlled by the valve 20. When the valve 20 is closed, the dilution air flowing through the dilution air line 12 does not flow through the bypass line 18. When the valve 20 is open, some of the dilution air flowing through the dilution air line 12 flows through the bypass line 18, and the remainder of the dilution air flowing through the dilution air line 12 flows through the inlet line 24.

[0034] The enclosure 28 has an inlet port 50 and an outlet port 52 and is configured to house the device to be inspected (battery, cell, module, etc.) 54 inside. Each of the inlet lines 24 branches off from a valve 22 and communicates with one of the inlet ports 50 and has one of the heaters 26. The outlet port 52 communicates with a tube 30.

[0035] The dilution air that flows into valve 22 is then distributed between inlet ports 24, where it is heated by heater 26 before entering housing 28. The waste from the device 54 under inspection is taken into the dilution air to generate a diluted sample gas. This diluted sample gas flows into tube 30 through outlet port 52.

[0036] Since the bypass line 18 communicates with tube 30 located downstream of outlet port 52, the mass flow rate to tube 30 is the sum of the mass flow rate Qa of the gas flowing through the dilution air line 12 and the mass flow rate Qs of the emissions from the device under inspection 54. Qs is calculated as will be explained in more detail below.

[0037] Tube 30 defines a port 56 and has a heater 32. Each of the analysis lines 36 communicates with one of the ports 56, has one of the valves 38, and is connected to one of the analyzers 34. The flow rate through one of the analysis lines 36 is controlled by the valve 38 above it. When the valve 38 is closed, the diluted sample gas flowing through tube 30 does not flow through one of the analysis lines 36. When the valve 38 is open, a portion of the diluted sample gas flowing through tube 30 flows through one of the analysis lines 36. The mass flow rate Qs of the gas flowing through one of the analysis lines 36 n This can be measured by the analytical device 34 connected to it. In this example, there are four analytical devices 34 and four analytical lines 36 (n=4). Therefore, there are four mass flow rates flowing through the analytical lines 36: Qs1, Qs2, Qs3, and Qs4. In other examples, the number of analytical devices 34 and analytical lines 36 may be fewer or more.

[0038] Tube 30 further includes a filter 40, a mass flow meter 42, and a valve 44 downstream of port 56. The mass flow meter 42, located downstream of the filter 40, measures the mass flow rate Qt of the gas passing through tube 30. The flow rate of the gas passing through tube 30 is controlled by the valve 44, located downstream of the mass flow meter 42. Moving the valve 44 to the closed position decreases the flow rate of the gas passing through tube 30. Opening the valve 44 to the open position increases the flow rate of the gas passing through tube 30.

[0039] In this example, the pump 46 is connected to the tube 30 downstream of the valve 44 and is used to generate suction throughout the system to draw fluid through the housing 28 and the tube 30. The flow rate through the tube can also be controlled by operating the pump 46.

[0040] The controller 48 communicates with and controls the mass flow meter 16, valves 20 and 22, heater 26, heater 32, analyzer 34, valve 38, mass flow meter 42, valve 44, and pump 46. For example, the controller 48 can generate commands to open and close valves 20, 22, 38, and 44, and commands to operate heaters 26 and 32, etc. The controller 48 can also receive the various mass flow rate data mentioned above and calculate Qs and the dilution coefficient DF according to the following formula. Qs = Qs1 + Qs2 + Qs3 + Qs4 + Qt - Qa (1) DF = (Qa + Qs) / Qs (2) The controller 48 can also calculate the actual concentration of the gas emitted from the device 54 under test by subtracting the background concentration of the diluted air from the product obtained by multiplying the concentration measured by the analyzer by DF.

[0041] The algorithms, methods, or processes disclosed herein are deliverable or implementable in a computer, controller, or processing unit, which may include any dedicated or programmable electronic control unit. Similarly, the algorithms, methods, or processes can be stored as executable data and instructions by a computer or controller in various forms, including but not limited to information permanently stored in a non-writable storage medium such as a read-only memory device, and information mutably stored in a writable storage medium such as a compact disk, random-access memory device, or other magnetic and optical media. The algorithms, methods, or processes can also be implemented in a software executable object. Alternatively, the algorithms, methods, or processes can be embodied in whole or in part using appropriate hardware components such as application-specific integrated circuits, field-programmable gate arrays, state machines, other hardware components or devices, or combinations of firmware, hardware, and software components.

[0042] While exemplary embodiments have been described above, these embodiments do not describe all possible forms that may be included in the claims. For example, the pump 46 may be located upstream of the inspection arrangement 10 instead of downstream. Naturally, other components and variations should also be considered.

[0043] The terms used herein are descriptive rather than restrictive, and it is understood that they may be modified in various ways without deviating from the gist and scope of the disclosed material. For example, the terms “controller” and “multiple controllers” can be used interchangeably because the functionality of one controller can be distributed across multiple controllers / modules that can communicate with each other via standard technologies.

[0044] As described above, features of various embodiments can be combined to form further embodiments of the present invention not explicitly described or illustrated. While various embodiments have been described as having advantages or being preferable to other embodiments or prior art practices with respect to one or more desired characteristics, those skilled in the art will recognize that, depending on the particular application and implementation, one or more features or characteristics may be compromised to achieve desired overall system attributes. These attributes include, but are not limited to, strength, durability, marketability, appearance, packaging, size, maintainability, weight, manufacturability, and ease of assembly. Therefore, embodiments described as being undesirable to other embodiments or prior art practices with respect to one or more characteristics are not outside the scope of this disclosure and may be desirable for particular applications.

Claims

1. A dilution and sampling system for sealed battery waste, A housing configured to fully enclose the battery, having at least one inlet port at one end and an outlet port at the other end that communicates with the heating exhaust pipe, Dilution air line, At least one heating inlet line is provided at one end of the dilution air line and communicates with the at least one inlet port, A bypass line is connected between the dilution air line and the heating exhaust pipe and is arranged around the housing, (i) a pump arranged to flow a portion of the diluted air from the diluted air line into the housing on the at least one heating inlet line and the battery, to take in the discharge from the battery to generate a diluted sample gas which is flowed to the outlet port, and to flow the remainder of the diluted air into the bypass line around the housing, and (ii) a pump arranged to mix the diluted sample gas and the remainder of the diluted air in the heating exhaust pipe, A controller programmed to calculate the mass flow rate of the exhaust as the difference between the mass flow rate of the gas passing through the heating exhaust pipe and the mass flow rate of the gas passing through the dilution air line, A sealed battery discharge dilution and sampling system comprising the following features.

2. The system according to claim 1, wherein the mass flow rate of the gas passing through the heating exhaust pipe is the sum of the mass flow rate of the gas passing through the analyzer associated with the heating exhaust pipe and the mass flow rate of the gas passing through the pump.

3. The system according to claim 1, further comprising one or more valves on the dilution air line configured to establish a flow splitting ratio between a portion of the dilution air and the remainder of the dilution air.

4. The system according to claim 3, wherein the controller is further programmed to perform proportional-integral-derivative control to achieve the flow division ratio based on the temperature of the gas in the heated exhaust pipe.

5. The system according to claim 3, wherein one or more of the valves are piezoelectric valves or needle valves.

6. The system according to claim 1, wherein the controller is further programmed to purge the housing with diluted air for a predetermined period of time before the discharge of the battery begins.

7. The system according to claim 1, wherein the housing is arranged to allow a portion of the flow of the diluted air to pass through the at least one heating inlet line and the housing and flow vertically over the battery.

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