DEMS in-situ gas testing module and testing system

Abstract

This invention relates to a DEMS in-situ gas testing module and system. The DEMS in-situ gas testing module includes: an upper mold base with a gas outlet section at its top; and a lower mold base threadedly connected to the upper mold base. The lower mold base contains a gas microchannel, which includes a connected spiral passage and a gas inlet section. The spiral passage includes multiple annular channels with diameters gradually decreasing from the outside to the inside, and each annular channel has an opening. A battery active material assembly is disposed between the upper and lower mold bases. When gas enters from the gas inlet section, it diffuses fully through the spiral passage, reacts fully with the battery active material assembly, and flows out from the gas outlet section. This invention is more advantageous for detecting trace gas changes in the DEMS in-situ gas testing module.

Description

Technical Field

[0001] This invention relates to the field of in-situ gas analysis technology, and in particular to a DEMS in-situ gas testing module and testing system. Background Technology

[0002] Differential electrochemical mass spectrometry (DEMS) is a modern in-situ electrochemical testing method that combines electrochemistry and mass spectrometry. DEMS is also the only analytical technique capable of online quantitative determination of electrochemical reaction products. It can detect volatile gaseous products and kinetic parameters, intermediates, and their structural properties in electrochemical reactions. By characterizing the changes in product distribution under different reaction systems (such as the composition of the electrolyte solution and the structure of the catalyst), the reaction mechanism can be revealed, and information such as the catalyst activity, selectivity, and stability of the catalyst material itself can be obtained. This information provides important experimental and theoretical basis for further guiding catalyst design and optimizing reaction conditions to control reaction performance. When the electrode reaction products are co-deposited, DEMS technology can simultaneously determine the change of the Faraday current of each product with electrode potential or time. When using DEMS to detect the change of a product signal peak with electrode reaction conditions, the analysis of the source of the signal peak is crucial for the qualitative and subsequent quantitative analysis of the product.

[0003] Typically, for operational feasibility, researchers use in-situ gas testing modules in conjunction with differential electrochemical mass spectrometry to monitor gas production or consumption during battery reactions.

[0004] The proper design of in-situ gas testing modules is particularly important for gas monitoring and battery evaluation. Currently, existing in-situ gas testing modules (such as...) Figure 1 The gas path design shown is unreasonable. Its gas path adopts the form of "top in and top out". On the one hand, it cannot allow the reaction gas to fully contact the active material. On the other hand, it is easy to cause the gas path to be blocked by the generated gas. It cannot fully carry the generated gas from the battery out of the in-situ gas test module, affecting the monitoring results, and even failing to achieve the effect of accurate real-time monitoring.

[0005] Therefore, in order to address this issue, it is imperative to innovate and redesign the in-situ battery mold pool structure to achieve more thorough and minute in-situ monitoring of battery gas generation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses a DEMS in-situ gas testing module and testing system.

[0007] The technical solution adopted in this invention is as follows:

[0008] A DEMS in-situ gas testing module includes:

[0009] The upper mold base has a gas outlet section at its top;

[0010] The lower mold base is threadedly connected to the upper mold base; wherein, the lower mold base is provided with a gas microchannel, the gas microchannel includes a connected spiral passage and a gas inlet section, the spiral passage includes multiple annular channels, the diameter of the multiple annular channels gradually decreases from the outside to the inside, and each annular channel is provided with a channel opening;

[0011] A battery active material assembly is disposed between the upper mold base and the lower mold base;

[0012] When the gas enters from the gas inlet section, it diffuses fully through the spiral passage, reacts fully with the battery active material components, and then flows out from the gas outlet section.

[0013] Its further technical feature is that both the upper mold base and the lower mold base are cylindrical.

[0014] Its further technical feature is that: there are two gas inlet sections, and the two gas inlet sections are symmetrically arranged on both sides of the lower mold base.

[0015] A further technical feature is that: a connecting portion is provided along the radial direction of the lower mold base, and the number of the connecting portions is the same as the number of the gas inlet sections.

[0016] Its further technical feature is that: the multiple annular channels are arranged concentrically; the center lines connecting the openings of two adjacent annular channels intersect.

[0017] Its further technical feature is that: the battery active material assembly includes a support, a positive electrode material, a separator and a negative electrode material, and the support supports the positive electrode material, the separator and the negative electrode material.

[0018] Its further technical feature is that the support includes a gasket and / or a spring.

[0019] Its further technical features are: it also includes a positive terminal and a negative terminal, the positive terminal being disposed on the top of the upper mold base, and the negative terminal being disposed on the side wall of the lower mold base.

[0020] A DEMS in-situ gas testing system includes:

[0021] Differential electrochemical mass spectrometry,

[0022] The DEMS in-situ gas testing module described above is electrically connected to the differential electrochemical mass spectrometer.

[0023] Its further technical features include: a gas collecting tank, a filter, a mass gas flow meter, and a cold trap. The gas collecting tank, the filter, the mass gas flow meter, the DEMS in-situ gas testing module, the cold trap, and the differential electrochemical mass spectrometer are connected in sequence, and valves are provided between the mass gas flow meter and the DEMS in-situ gas testing module, and between the DEMS in-situ gas testing module and the differential electrochemical mass spectrometer.

[0024] The technical solution of the present invention has the following advantages compared with the prior art:

[0025] 1. The modified DEMS in-situ gas testing module of the present invention has smoother airflow and is less prone to clogging.

[0026] 2. The DEMS in-situ gas testing module of the present invention has a "bottom inlet and top outlet" gas flow column, with two gas inlet sections and one gas outlet section, i.e., dual-pipe inlet and single-pipe outlet, which makes the gas reaction more complete.

[0027] 3. The carrier gas of the DEMS in-situ gas testing module described in this invention can more effectively carry out the gas generated inside the mold.

[0028] 4. Experimental tests show that the modified mold of the DEMS in-situ gas testing module described in this invention is more conducive to the observation of trace gas production. Attached Figure Description

[0029] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0030] Figure 1 This is a physical image of an existing in-situ gas testing module.

[0031] Figure 2 This is a schematic diagram of the DEMS in-situ gas testing module in this invention.

[0032] Figure 3 This is a top view of the DEMS in-situ gas testing module in this invention.

[0033] Figure 4 This is a left view of the DEMS in-situ gas testing module in this invention.

[0034] Figure 5 This is a physical image of the DEMS in-situ gas testing module in this invention.

[0035] Figure 6 This is a schematic diagram of the DEMS in-situ gas testing system in this invention.

[0036] Figure 7 This is a comparison chart of the gas production test results of existing in-situ gas testing modules and the DEMS in-situ gas testing module of this invention.

[0037] Explanation of reference numerals in the accompanying drawings: 1. Lower mold base; 2. Gas microchannel; 201. Gas inlet section; 202. Gas outlet section; 3. Positive electrode post; 4. Negative electrode post; 5. Connecting part; 6. Upper mold base; 7. Positive electrode material; 8. Diaphragm; 9. Negative electrode material; 10. Gasket; 11. Spring; 12. Gas collecting tank; 13. Filter; 14. Mass flow meter; 15. Check valve; 16. Cold trap; 17. Shut-off valve; 18. Differential electrochemical mass spectrometer. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0039] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention. Furthermore, in all embodiments, the same reference numerals denote the same elements.

[0040] Example 1:

[0041] Combination Figures 2-4 A DEMS in-situ gas testing module, comprising:

[0042] The upper mold base 6 has a gas outlet section 202 at its top;

[0043] The lower mold base 1 is threadedly connected to the upper mold base 6; wherein, the lower mold base 1 is provided with a gas microchannel 2, the gas microchannel 2 includes a connected spiral passage and a gas inlet section 201, the spiral passage includes multiple annular channels, the diameter of the multiple annular channels gradually decreases from the outside to the inside, and each annular channel is provided with a channel opening;

[0044] The battery active material assembly is disposed between the upper mold base 6 and the lower mold base 1;

[0045] When the gas enters from the gas inlet section 201, it diffuses fully through the spiral passage, reacts fully with the battery active material components, and flows out from the gas outlet section 202.

[0046] The above provides a DEMS in-situ gas testing module, which solves the problem that existing in-situ gas testing modules cannot fully extract the gas generated by the battery from the in-situ gas testing module, affecting the monitoring results and even failing to achieve accurate real-time monitoring.

[0047] In this embodiment, both the upper mold base 6 and the lower mold base 1 are cylindrical. The upper mold base 6 can be made of a nut, and its inner ring has multiple threads. Correspondingly, the outer ring of the lower mold base 1 has multiple threads. When the operator tightens the upper mold base 6 and the lower mold base 1, the threads of the upper mold base 6 and the lower mold base 1 mesh with each other.

[0048] In this embodiment, there are two gas inlet sections 201, which are symmetrically arranged on both sides of the lower mold base 1. Specifically, the central axes of the two gas inlet sections 201 are on the same horizontal line, which can better balance the weight of the lower mold base 1 and ensure its stability. Of course, the number of gas inlet sections 201 is not limited to two. According to the needs of those skilled in the art, the number of gas inlet sections 201 is preferably an even number.

[0049] In this embodiment, connecting portions 5 are arranged radially along the lower mold base 1, and the number of connecting portions 5 is the same as the number of gas inlet sections 201. Therefore, the connecting portions 5 protect the gas inlet sections 201, and the length of the gas inlet section 201 is less than or equal to the length of the connecting portion 5, and the outer diameter of the gas inlet section 201 is less than the inner diameter of the connecting portion 5.

[0050] In this embodiment, multiple annular channels are arranged concentrically; the center lines connecting the openings of two adjacent annular channels intersect. Specifically, when there are nine annular channels, for ease of description, they are designated as the first annular channel, the second annular channel, the third annular channel, the fourth annular channel, the fifth annular channel, the sixth annular channel, the seventh annular channel, the eighth annular channel, and the ninth annular channel, corresponding to the number of gas inlet sections 201, and each of the nine annular channels has two openings.

[0051] Preferably, the lines connecting the two openings of the first annular channel and the two openings of the second annular channel are perpendicular to each other, the lines connecting the two openings of the second annular channel and the two openings of the third annular channel are perpendicular to each other, and so on. The lines connecting the two openings of two adjacent annular channels are set perpendicular to each other to increase the gas flow path, make the airflow smoother, less prone to blockage, and make the gas reaction in the test module more complete, which is conducive to observing trace gas production.

[0052] It should be noted that the two entrances of the same circular channel are not necessarily on the same straight line. The two entrances of the same circular channel may form a broken line. It is only necessary to satisfy that the lines connecting the entrances of two adjacent circular channels intersect.

[0053] In this embodiment, the battery active material assembly includes a support, a positive electrode material 7, a separator 8, and a negative electrode material 9. The support supports the positive electrode material 7, the separator 8, and the negative electrode material 9. The support includes a gasket 10 and / or a spring 11. Specifically, the positive electrode material 7 includes, but is not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese phosphate, lithium iron manganese phosphate, and lithium iron phosphate. The separator 8 can be selected from commonly used battery separator materials, including, but not limited to, one or more of polypropylene separators, polyethylene separators, polyimide separators, and cellulose nonwoven separators. The negative electrode material 9 is selected from, but is not limited to, one or more of natural graphite, artificial graphite, mesophase carbon microspheres, soft carbon and hard carbon, elemental silicon, silicon oxide, silicon-carbon, and silicon alloys.

[0054] In this embodiment, the DEMS in-situ gas testing module further includes a positive electrode post 3 and a negative electrode post 4. The positive electrode post 3 is disposed on the top of the upper mold base 6, and the negative electrode post 4 is disposed on the side wall of the lower mold base 1. The positive electrode post 3 and the negative electrode post 4 are electrically connected to the differential electrochemical mass spectrometer 18.

[0055] like Figure 5 As shown, the applicant has designed a physical prototype based on the above technical solution, and compared the gas production test results of the existing in-situ gas testing module and the DEMS in-situ gas testing module of this invention to prove the technical advantages of this invention.

[0056] like Figure 7 As shown, figures a and b are ion current values ​​and relative gas concentration percentages observed during battery operation using an existing in-situ gas testing module; figures c and d are ion current values ​​and relative gas concentration percentages observed during battery operation using the DEMS in-situ gas testing module of this invention.

[0057] By comparing the ion current value and the percentage of relative gas concentration, it can be seen that, under the same conditions, the CO2 gas generated by the battery during operation is more clearly detected using this DEMS in-situ gas testing module.

[0058] Example 2:

[0059] like Figure 6 As shown, a DEMS in-situ gas testing system includes:

[0060] Differential electrochemical mass spectrometer 18,

[0061] The DEMS in-situ gas testing module provided in Example 1 is electrically connected to the differential electrochemical mass spectrometer 18.

[0062] In this embodiment, the DEMS in-situ gas testing system also includes a gas collection tank 12, a filter 13, a mass gas flow meter 14, and a cold trap 16. The gas collection tank 12, filter 13, mass gas flow meter 14, DEMS in-situ gas testing module, cold trap 16, and differential electrochemical mass spectrometer 18 are connected in sequence, and valves are provided between the mass gas flow meter 14 and the DEMS in-situ gas testing module, and between the DEMS in-situ gas testing module and the differential electrochemical mass spectrometer 18.

[0063] Specifically, the gas collecting tank 12 releases argon (Ar), and the filter 13 filters the gas released from the gas collecting tank 12.

[0064] The working principle of the mass flow meter 14 is based on the heat transfer principle that the mass of gas flowing through the sensor is proportional to the output voltage (current). The mass flow meter 14 consists of a gas flow mass sensor and a digital integrator. The mass flow meter 14 uses an existing microbridge gas flow sensor, which converts the gas flow mass into an electrical signal. The digital integrator uses an imported computer chip to convert the electrical signal output by the sensor into a digital signal, which is then processed and accumulated to convert the gas mass into the corresponding volume under standard conditions, displayed on a digital display.

[0065] A cold trap 16 is a device that prevents vapor or liquid from entering a measuring instrument from a system, or from entering a system from a measuring instrument. It provides a very low-temperature surface on which molecules can condense and increase the vacuum level by one to two orders of magnitude.

[0066] The differential electrochemical mass spectrometer 18 is a commercially available instrument for separating and detecting different isotopes. Its model can be selected and adjusted by those skilled in the art as needed.

[0067] The working principle of this embodiment is as follows:

[0068] The DEMS in-situ gas testing system can analyze trace amounts of gas generated or consumed by energy storage devices such as lithium-ion batteries, sodium-ion batteries, and metal-air batteries in situ during operation. It can analyze and detect the gas consumption or generation at different stages of battery operation in real time, thereby obtaining qualitative and quantitative information on gas participation or gas release in electrochemical reactions.

[0069] Specifically, in electrocatalytic testing, relying on vacuum pressure difference as the driving force, the gas, volatile products or intermediate products generated by the electrochemical reaction on the electrode surface are extracted into the mass spectrometer within milliseconds through a water-resistant and gas-permeable membrane, thereby achieving high sensitivity and high resolution detection of the products. It is mainly used in electrocatalytic reactions such as MOR, EOR, CO2RR, HER, OER, ORR, NRR, nitrate reduction, and ammonia oxidation.

[0070] Specifically, the electrochemical reaction apparatus is connected to a mass spectrometer. Volatile products generated by the electrochemical reaction enter the vacuum system of the mass spectrometer through a hydrophobic and gas-permeable membrane interface. The mass spectrometer then obtains the changes in current over time for ions with different mass-to-charge ratios. Cyclic voltammetry (CV) is a commonly used electrochemical technique in the study of electrochemical reaction mechanisms, and rich electrochemical information can be obtained from the obtained CV graphs.

[0071] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0072] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A DEMS in-situ gas testing module characterized by: include: The upper mold base (6) has a gas outlet section (202) at its top. The lower mold base (1) is threadedly connected to the upper mold base (6); wherein, the lower mold base (1) is provided with a gas microchannel (2), the gas microchannel (2) includes a connected spiral passage and a gas inlet section (201), the number of gas inlet sections (201) is an even number, the spiral passage includes multiple annular channels, the multiple annular channels are arranged concentrically, the diameter of the multiple annular channels gradually decreases from the outside to the inside, and each annular channel is provided with a channel opening, the center line connecting the channel openings of two adjacent annular channels intersects; corresponding to the number of gas inlet sections (201), each annular channel has the same number of channel openings as the number of gas inlet sections (201); A battery active material assembly is disposed between the upper mold base (6) and the lower mold base (1); When the gas enters from the gas inlet section (201), it diffuses fully through the spiral passage, reacts fully with the battery active material components, and flows out from the gas outlet section (202).

2. The DEMS in-situ gas test module of claim 1, wherein: Both the upper mold base (6) and the lower mold base (1) are cylindrical.

3. The DEMS in-situ gas test module of claim 1, wherein: There are two gas inlet sections (201), and the two gas inlet sections (201) are symmetrically arranged on both sides of the lower mold base (1).

4. The DEMS in-situ gas test module of claim 1, wherein: A connecting part (5) is provided radially along the lower mold base (1), and the number of the connecting parts (5) is the same as the number of the gas inlet section (201).

5. The DEMS in-situ gas test module of claim 1, wherein: Multiple annular channels are arranged concentrically; the center lines connecting the openings of two adjacent annular channels intersect.

6. The DEMS in-situ gas test module of claim 1, wherein: The battery active material assembly includes a support, a positive electrode material (7), a separator (8), and a negative electrode material (9), wherein the support supports the positive electrode material (7), the separator (8), and the negative electrode material (9).

7. The DEMS in-situ gas test module of claim 6, wherein: The support includes a gasket (10) and / or a spring (11).

8. The DEMS in-situ gas test module of claim 1, wherein: It also includes a positive terminal (3) and a negative terminal (4), wherein the positive terminal (3) is disposed on the top of the upper mold base (6) and the negative terminal (4) is disposed on the side wall of the lower mold base (1).

9. A DEMS in-situ gas testing system characterized by: include: Differential electrochemical mass spectrometer (18). The DEMS in-situ gas testing module as described in any one of claims 1-8 is electrically connected to the differential electrochemical mass spectrometer (18).

10. The DEMS in-situ gas testing system of claim 9, wherein: It also includes a gas collection tank (12), a filter (13), a mass gas flow meter (14), and a cold trap (16). The gas collection tank (12), the filter (13), the mass gas flow meter (14), the DEMS in-situ gas testing module, the cold trap (16), and the differential electrochemical mass spectrometer (18) are connected in sequence, and valves are provided between the mass gas flow meter (14) and the DEMS in-situ gas testing module, and between the DEMS in-situ gas testing module and the differential electrochemical mass spectrometer (18).

Images