Thermal decomposition device and substance content measuring system

Abstract

The utility model belongs to the technical field of batteries, and discloses a thermal decomposition device and a substance content determination system. The device comprises a weighing device, a base, a carrying piece and a cover body, the weighing device comprises a weighing platform, and the weighing platform is provided with a first weighing area and a second non-weighing area; the base is arranged above the weighing table and is fixedly connected with the weighing device in the second area, and the base is provided with a heating table in the first area; an object carrying piece is arranged above the heating table, a containing cavity for containing a to-be-detected substance is formed in the object carrying piece, and the heating table heats the to-be-detected substance so that the to-be-detected substance can be decomposed to generate gas; a supporting piece is fixed to the object carrying piece, penetrates through the base in a sealed mode and is fixedly connected with the weighing device in the first area. The cover body and the base form a sealed cavity, the cover body is provided with an air inlet, an air outlet and a vacuum port which are communicated with the sealed cavity, the vacuum port vacuumizes the sealed cavity, and the air inlet inputs inert gas into the sealed cavity. The device can improve the accuracy of measuring the content of the alkaline compound.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, specifically relating to a heating decomposition device and a substance content determination system. Background Technology

[0002] The lithium source commonly used in the synthesis of cathode materials for lithium-ion batteries is a lithium-containing alkaline compound, such as lithium hydroxide (LiOH) or lithium carbonate (Li2CO3). A high lithium ratio is typically used in the preparation process, and the residual alkali after the reaction exists in the form of LiOH and Li2CO3. High LiOH and Li2CO3 content in the cathode material results in high viscosity during slurry preparation, affecting the processing performance of the cathode material. Furthermore, excessively high LiOH and Li2CO3 content can cause the battery to swell during high-temperature storage, leading to a decrease in cathode material capacity and safety issues. Therefore, the residual alkali content in the cathode material must be strictly controlled.

[0003] Existing devices for measuring residual alkali content in cathode materials are not accurate in measuring residual alkali content, and the measurement process may affect the structural morphology and electrochemical performance of the cathode material. Utility Model Content

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a heating decomposition device and a substance content determination system to solve the problem of inaccurate measurement of residual alkali content in cathode materials.

[0005] A first aspect of this utility model provides a heating decomposition apparatus, comprising:

[0006] A weighing device, the weighing device including a weighing platform having a first weighing area and a second area located outside the first area;

[0007] A base is disposed above the weighing platform and is fixedly connected to the weighing device in the second region. A heating platform is disposed on the base in the first region.

[0008] A carrier is disposed above the heating stage. The carrier has a cavity for holding a substance to be tested. The heating stage is used to heat the substance to be tested to decompose it and produce at least one gas.

[0009] A support is fixed on the carrier, the support passes through the base in a sealed manner and is fixedly connected to the weighing device at the first region, and the weighing device is used to obtain the mass and mass change of the substance to be tested.

[0010] A cover body is fitted onto the base and forms a sealed cavity with the base. The cover body has an air inlet, an air outlet, and a vacuum port that communicate with the sealed cavity. The vacuum port is used to evacuate the sealed cavity. The air inlet is used to introduce inert gas into the sealed cavity so that the substance to be tested decomposes under the protection of the inert gas to produce at least one gas. The air outlet is used to discharge the gases.

[0011] The heating decomposition device provided by this utility model has a simple structure. It can heat and decompose alkaline compounds in the test substance to produce gas under the protection of inert gas, avoiding interference from air and other factors in the measurement of alkaline compound content, improving the accuracy of alkaline compound measurement, and has a low detection limit and high sensitivity. It can also realize non-aqueous testing of alkaline compounds in the test substance without affecting the structure, morphology and electrochemical performance of the test substance.

[0012] In addition, the heating decomposition device of this utility model may also have the following additional technical features:

[0013] As one possible implementation, the heating platform has a heating plane on the side away from the base, and the heating plane contacts and engages with the loading object;

[0014] Alternatively, the heating platform may have an assembly groove on the side away from the base, and the load may extend at least partially into the assembly groove.

[0015] As an implementation method, the cover includes a cavity with a bottom opening, a partition is provided in the cavity, the partition divides the cavity into a first sub-cavity and a second sub-cavity that are spaced apart vertically, and the partition is provided with a plurality of vent holes, which are connected to the first sub-cavity and the second sub-cavity.

[0016] The first sub-cavity is located above the second sub-cavity. The heating platform and the loading device are located inside the second sub-cavity. The cover has an air inlet and an air outlet on its two side walls opposite to the first sub-cavity. The inert gas flows in from the air inlet and flows out from the air outlet to form a negative pressure at the exhaust port, so that the gas flows out from the exhaust port to the air outlet.

[0017] As an alternative implementation, a pressure sensor is provided at the fixed connection between the support and the weighing device, and the weighing device obtains the mass of the substance to be measured based on the pressure sensor.

[0018] As an alternative implementation, there are multiple support members, which are circumferentially distributed on the outside of the load, and each support member is fixedly connected to the load via a connector.

[0019] As an alternative, the support member is fitted with a protective sleeve on its outer side.

[0020] As an alternative implementation, the heating decomposition apparatus further includes a cooling pipe that passes through the heating platform and has an inlet and an outlet for circulating a cooling medium into the cooling pipe to facilitate heat exchange between the cooling pipe and the heating platform.

[0021] As an alternative implementation, the base is provided with a groove on the side away from the weighing device and located in the first region, and the heating platform is assembled in the groove.

[0022] As an implementation method, a heating element is provided on the heating platform, and the heating element is used to heat the heating platform.

[0023] As an implementation method, the base is provided with slots around its perimeter, and the cover is fitted into the slots so that the cover and the base are sealed together to form the sealed cavity.

[0024] A second aspect of this utility model provides a substance content determination system. The system is used to determine the content of alkaline compounds in the substance to be tested. The system includes: a vacuum pump, a gas supply device, a mass spectrometer, a computer, and the heating decomposition device described in any embodiment of this application. The vacuum pump is connected to the vacuum port, the gas supply device is connected to the gas inlet, the mass spectrometer is connected to the gas outlet, and the signal output terminals of the mass spectrometer and the weighing device are electrically connected to the signal input terminal of the computer.

[0025] As an alternative implementation, the system further includes a cooling device connected to the inlet and outlet of the cooling pipe.

[0026] As an implementation method, the mass spectrometer is used to acquire the elution time and peak end time of various gases, and send the elution time and peak end time of various gases to a computer.

[0027] The weighing device is used to acquire the mass of the substance to be tested in real time and send the acquired mass of the substance to be tested to the computer.

[0028] The computer determines a mass change curve of the analyte over time based on the real-time mass of the analyte acquired by the weighing device. The computer also determines the mass of the analyte corresponding to the peak elution time and peak end time for each gas, based on the peak elution time and peak end time acquired by the mass spectrometer, and in conjunction with the mass change curve of the analyte over time. Based on the mass loss of the analyte corresponding to the peak elution time and peak end time for each gas, the computer determines the mass of the corresponding gas type. Furthermore, the computer determines the mass percentage of the gas in the analyte based on the gas mass and the initial mass of the analyte acquired by the weighing device, and, in conjunction with the heating decomposition equation of the analyte, determines the mass percentage of the alkaline compound in the analyte.

[0029] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0031] Figure 1 A three-dimensional structural diagram of the heating decomposition apparatus provided in the embodiments of this application;

[0032] Figure 2 A perspective structural diagram of the heating and decomposition apparatus (cover not shown) provided in an embodiment of this application;

[0033] Figure 3 A top view of the heating and decomposition apparatus (cover not shown) provided in an embodiment of this application;

[0034] Figure 4 A structural diagram of the weighing device provided in the embodiments of this application;

[0035] Figure 5 A three-dimensional structural diagram of the cover provided in the embodiments of this application;

[0036] Figure 6 This is a cross-sectional view of the cover provided in an embodiment of this application;

[0037] Figure 7 Structural diagram of the carrier provided in the embodiments of this application;

[0038] Figure 8 This is a structural diagram of the substance content determination system provided in the embodiments of this application.

[0039] In the above image:

[0040] 100 Heating and decomposition device;

[0041] 110 Weighing device; 111 First zone; 112 Second zone; 113 Support; 114 Connector; 115 Display; 116 Controller;

[0042] 120 Base; 121 Groove; 122 Slot;

[0043] 130 Heating platform; 131 Heating element;

[0044] 140 Loading container; 141 Receiving cavity;

[0045] 150 Cover; 151 Air inlet; 152 Air outlet; 153 Vacuum port; 154 Partition; 155 Exhaust vent;

[0046] 160 Cooling pipe; 161 Liquid inlet; 162 Liquid outlet;

[0047] 200 Vacuum pump; 210 Gas supply equipment; 220 Mass spectrometer; 230 Cooling equipment; 240 Computer. Detailed Implementation

[0048] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0051] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0052] In the description of this specification, the terms "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0054] The lithium source commonly used in the synthesis of lithium-ion battery cathode materials is a lithium-containing alkaline compound, such as lithium hydroxide (LiOH) or lithium carbonate (Li₂CO₃). A high lithium ratio is typically used in the preparation process, and the residual alkali after the reaction exists in the form of LiOH and Li₂CO₃. High LiOH and Li₂CO₃ content in the cathode material results in high viscosity during slurry preparation, affecting the processing performance of the cathode material. Furthermore, excessively high LiOH and Li₂CO₃ content can cause the battery to swell during high-temperature storage, leading to a decrease in cathode material capacity and safety issues. Therefore, the residual alkali content in the cathode material must be strictly controlled. The residual alkali content refers to the percentage of the mass of residual alkali after the cathode material reaction relative to the total mass of the cathode material.

[0055] Current methods for measuring residual alkali content on the surface of cathode materials employ potentiometric titration. This involves mixing the cathode material with water to extract the residual alkali, followed by titration to determine the alkali content. However, for alkaline compounds such as lithium-rich or high-nickel (Ni) materials, dissolving the alkali in water can cause lithium leaching from the material's crystal lattice, resulting in an inflated alkali content reading. For example, with lithium-replenishing agents like Li5FeO4 and Li2NiO2 introduced to improve battery energy density and cycle performance, conventional electrochemical titration after dissolving them in water results in continuous lithium leaching, leading to alkali content readings as high as 40%. Even with alcohol solvents, the measured alkali content remains close to 10%, which is clearly inconsistent with the actual alkali content. Furthermore, high-Ni cathode materials are highly sensitive to water; washing away residual Li compounds inevitably affects the material's structure, morphology, and electrochemical performance. Therefore, achieving non-aqueous detection of residual alkali on the cathode material surface is a pressing issue that needs to be addressed.

[0056] Existing methods involve placing the cathode material sample in a reaction chamber crucible, adding flux, and heating it in an oxygen atmosphere to generate carbon dioxide (CO2). The relative carbon content of the carbon dioxide is then measured using a carbon content testing instrument, and this relative carbon content is used as an indicator of the relative alkali content on the cathode material surface. However, this method only measures the CO2 content. Since the cathode material surface contains not only Li2CO3 but also LiOH, using only carbon content as an indicator of surface alkali content is not accurate enough.

[0057] Another method involves exposing the cathode material to a dry CO2 atmosphere for a period of time, allowing residual alkalis such as LiO2 and LiOH to be converted into Li2CO3, and then determining the Li2CO3 content through electrochemical titration. However, this method cannot guarantee that all residual alkalis such as LiO2 and LiOH in the sample will be converted into Li2CO3 after exposure to CO2 for a period of time, and it does not provide corresponding detection methods, thus failing to guarantee the accuracy of the results.

[0058] To solve the above-mentioned technical problems, the first aspect of this utility model refers to... Figures 1 to 7 A heating decomposition apparatus 100 is provided, comprising:

[0059] Weighing device 110, the weighing device 110 includes a weighing platform, the weighing platform having a first weighing area 111 and a second area 112 located outside the first area 111.

[0060] A base 120 is disposed above the weighing platform and is fixedly connected to the weighing device 110 in the second region 112. A heating platform 130 is disposed on the base 120 in the first region 111.

[0061] The object carrier 140 is disposed above the heating stage 130. The object carrier 140 has a receiving cavity 141, which is used to place the substance to be tested. The heating stage 130 is used to heat the substance to be tested so that the substance to be tested decomposes to produce at least one gas.

[0062] A support member 113 is fixed on the carrier 140. The support member 113 passes through the base 120 and is fixedly connected to the weighing device 110 at the first region 111. The weighing device 110 is used to obtain the mass and mass change of the substance to be tested.

[0063] A cover 150 is provided, which covers the base 120 and forms a sealed cavity with the base 120. The cover 150 is provided with an air inlet 151, an air outlet 152 and a vacuum port 153 communicating with the sealed cavity. The vacuum port 153 is used to evacuate the sealed cavity. The air inlet 151 is used to introduce inert gas into the sealed cavity so that the substance to be tested decomposes under the protection of the inert gas to produce at least one gas. The air outlet 152 is used to discharge the gases.

[0064] Specifically, the analyte includes at least one basic compound and / or at least one acidic compound, which can decompose to produce gas under heating conditions. The acidic compound can be oxalic acid (H₂C₂O₄), nitric acid (HNO₃), formic acid, acetic acid, ammonium bicarbonate, etc.; the basic compound can be sodium carbonate (Na₂CO₃), Li₂CO₃, LiOH, etc. The principle for determining the mass ratio of the acidic and basic compounds in the analyte is the same; this application uses a basic compound as an example for illustrative purposes.

[0065] In some embodiments, the analyte may include an alkaline compound that decomposes upon heating to produce one or more gases; or, the analyte may include two or more alkaline compounds, each of which decomposes upon heating to produce a corresponding gas. The analyte can be a positive or negative electrode material of a battery. The alkaline compounds included in the positive electrode material generally include Li₂CO₃, LiOH, etc. Li₂CO₃ decomposes upon heating to produce CO₂, and LiOH decomposes upon heating to produce water (H₂O) vapor. The decomposition temperature of LiOH is 900–1000°C, and the decomposition temperature of Li₂CO₃ is 700–1300°C.

[0066] refer to Figure 7 The cavity 141 of the carrier 140 is used to place the substance to be tested. The carrier 140 can be a crucible, which is made of high-temperature resistant material, such as ceramic, platinum and other high-temperature resistant materials.

[0067] refer to Figure 1 , Figure 2 and Figure 4 As a weighing device, the weighing instrument 110 can acquire the mass of the substance to be measured in the container 140 in real time, and thus obtain a curve of the mass of the substance to be measured changing over time.

[0068] The heating stage 130 can heat the substance to be tested, causing the alkaline compounds within the substance to decompose and generate gas. The heating stage 130 can control the heating rate and temperature of the substance, enabling linear temperature rise and constant temperature settings at different levels. The heating stage 130 is preferably made of high-temperature resistant materials, providing a heating temperature range from room temperature to 1500°C to meet the heating temperature requirements of different substances. For example, the heating stage 130 can be made of ceramics, graphene, silicon carbide, stainless steel, etc.

[0069] The base 120 serves as a support for the heating stage 130, providing stable support for the heating stage 130. It can also form a sealed cavity with the cover 150. The air in the sealed cavity can be discharged through the vacuum port 153 provided on the cover 150, so that the substance to be tested in the carrier 140 can be heated and decomposed in a vacuum environment. This avoids interference from CO2, H2O and other gases in the air on the gases produced by the decomposition of alkaline compounds, thus preventing inaccurate measurement of alkaline compounds.

[0070] refer to Figure 5 and Figure 6 The air inlet 151 on the cover 150 is used to introduce inert gas, such as nitrogen, argon, or helium, into the sealed cavity, so that the alkaline compound is heated and decomposed under the protection of the inert gas, thus avoiding the problem of inaccurate measurement caused by the oxidation of the alkaline compound.

[0071] Understandably, reference Figure 4 The weighing platform has a first weighing area 111 and a second weighing area 112. The second area 112 is located outside the first area 111. The heating platform 130 and the load 140 are both located in the first area 111, and the load 140 is fixedly connected to the first area 111 of the weighing platform via a support member 113, allowing the weighing device 110 to directly weigh the mass of the substance to be measured within the load 140. Although the heating platform 130 is located in the first area 111, it is directly fixed to the base 120, which is fixedly connected to the second area 112 of the weighing platform. Therefore, the heating platform 130 and the base 120 will not interfere with the weighing device 110's measurement of the substance to be measured within the load 140. The support rod can be a support rod or a spring, preferably made of a high-temperature resistant material such as stainless steel. A sealing element is provided at the connection between the support member 113 and the base 120. The sealing element is preferably made of a high-temperature resistant material, and the setting of the sealing element does not affect the vertical movement of the support member 113 relative to the base 120, so as to avoid interference with the weighing of the symmetrical weight 110 by the base 120 and other components.

[0072] The weighing platform of the weighing device 110 is also equipped with conventional components such as a display 115 and a controller 116. The mass information of the substance to be tested acquired by the weighing device 110 can be displayed on the display 115. The signal output terminal of the control module is electrically connected to the control terminal of the heating platform 130, so that the heating rate and heating temperature of the heating platform 130 can be controlled by the controller 116 program. The weighing device 110 is directly connected to the computer 240 via a network cable or USB cable. The computer 240 can record the initial mass and mass loss of the substance to be tested, the mass of the decomposed sample and the mass loss curve, and the mass change curve of the substance to be tested over time. The computer 240 can also control the heating platform, edit the program, and record the temperature change curve of the heating platform over time.

[0073] For example, if the analyte includes alkaline compound A and alkaline compound B, alkaline compound A decomposes upon heating to produce gas A1, and alkaline compound B decomposes upon heating to produce gas B1, the weighing device 110 acquires the mass of the analyte in real time and sends the acquired mass information to the computer 240. The computer 240 records the mass change curve of the analyte over time, and the mass spectrometer 220 acquires the peak times and peak ending times of gases A1 and B1 respectively. When the temperatures of gases A1 and B1 produced by heating and decomposition are completely separated and do not overlap... The mass spectrometer 220 can determine the substances A1 and B1 and obtain the peak elution and peak end times of A1 and B1 produced by thermal decomposition. The peak elution and peak end times of gas A1 and gas B1 do not overlap; that is, gas B1 begins to elute only after gas A1 has eluted. Combined with the curve of the mass change of the analyte over time, the mass of the analyte at the peak elution time and the mass at the peak end time of gas A1 can be determined. The mass m of gas A1 can be obtained using the difference in mass loss between the two. A1 Similarly, the mass m of gas B1 can be obtained. B1 .

[0074] Since the basic compound A decomposes upon heating to produce gas A1, according to the decomposition equation, the mass ratio of basic compound A to gas A1 is equal to its corresponding molar mass ratio. Therefore, the mass m of basic compound A is... A For: m A =m A1 ×x×M A / (y×M A1 ), where M A Let be the molar mass of basic compound A, x be the reaction coefficient of basic compound A, and y be the reaction coefficient of gaseous compound A1. Similarly, the mass m of basic compound B... B For: m B =m B1 ×a×MB / (b×M B1 ), where M B Let be the molar mass of basic compound B, a be the reaction coefficient of basic compound B, and b be the reaction coefficient of gaseous compound B1.

[0075] The content W of basic compound A A For: m A / m 0= m A1 ×x×M A / (y×M A1 ×m0), the content of basic compound B W B For m B / m 0= m B1 ×a×M B / (b×M B1 ×m0). It is understood that the content of alkaline compounds in this application refers to the mass percentage of alkaline compounds in the analyte. For example, if the analyte is a positive electrode material of a battery, and the mass of the positive electrode material is 5~10g, then the content of alkaline compounds in the positive electrode material is generally 0.01%~2.1%. Therefore, the heating decomposition device 100 provided in this application embodiment has high sensitivity and can be used for the measurement of alkaline substances at the mg level, such as for testing at the 0.1mg level.

[0076] It should be noted that when the mass m of gas A1 is obtained... A1 Then, the computer 240 can calculate the mass percentage W of gaseous Al in the analyte. A1 W A1= m A1 / m0, based on the heating decomposition equation, the content W of alkaline compound A is obtained. A For W A= W A1 ×x×M A / (y×M A1 ) = m A1 ×x×M A / (y×M A1 (×m0), consistent with the calculation results above. Similarly, when the mass m of gas B1 is obtained... B1 Then, computer 240 can calculate the mass percentage W of gas B1 in the analyte. B1 W B1= m B1 / m0, based on the heating decomposition equation, the content W of alkaline compound B is obtained. B For W B= W B1 ×a×M B / (b×M B1 ) =m B1 ×a×M B / (b×M B1 (×m0), which is consistent with the calculation results above.

[0077] It should be noted that when the temperatures of gases A1 and B1 produced by thermal decomposition cannot be completely separated and overlap, the mass percentage of each gas A1 and B1 in the analyte can be determined using mass spectrometry 220. Specifically, this involves preparing a series of analytes with known A and B mass percentages, performing thermal decomposition tests, and obtaining standard curves for A1 and B1 ion concentrations using mass spectrometry 220. When testing gases A1 and B1, the mass percentage W of A1 and B1 in the analyte can be determined by the relative ion intensity of the test results using mass spectrometry. A1 and W B1 By combining this with the heating decomposition method, the mass percentage of alkaline compounds A and B in the analyte can be obtained.

[0078] The heating decomposition device 100 provided in this application embodiment can heat and decompose alkaline compounds in the test substance to generate gas under the protection of inert gas, avoiding interference from air and other factors on the measurement of alkaline compound content, improving the accuracy of alkaline compound measurement, and having a low detection limit and high sensitivity. It can also realize non-aqueous testing of alkaline compounds in the test substance, avoiding the problem of high residual alkali content on the surface due to water dissolution and destruction of the structure and morphology of the test substance in potentiometric titration method, and lithium migration. It is especially suitable for measuring the residual alkali content in battery cathode materials.

[0079] In some embodiments, the heating platform 130 has a heating plane on the side away from the base 120, and the heating plane contacts and engages with the loading member 140;

[0080] Alternatively, the heating platform 130 may have an assembly groove on the side away from the base 120, and the loading component 140 may extend at least partially into the assembly groove.

[0081] For details, please refer to Figure 2 The upper surface of the heating stage 130 has a heating plane, which contacts and engages with the lower surface of the carrier 140 so that the material to be tested in the carrier 140 can be heated by the heating stage 130, and the heating stage 130 will not interfere with the weighing of the material to be tested.

[0082] Alternatively, an assembly slot can be provided at the upper end of the heating stage 130, allowing the carrier 140 to be assembled into the assembly slot. This ensures that the carrier 140 is heated more evenly, guaranteeing that the substance to be tested inside the carrier 140 is fully heated. Furthermore, the carrier 140 and the heating stage 130 are fitted with a clearance to avoid interference from the heating stage 130 on the weight detection of the substance to be tested inside the carrier 140, thereby improving the sensitivity and accuracy of the detection of the substance to be tested.

[0083] In some implementations, reference Figure 5 and Figure 6 The cover 150 includes a cavity with a bottom opening. A partition 154 is provided in the cavity. The partition 154 divides the cavity into a first sub-cavity and a second sub-cavity that are spaced apart vertically. A plurality of vent holes 155 are provided on the partition 154. The vent holes 155 are connected to the first sub-cavity and the second sub-cavity.

[0084] The first sub-cavity is located above the second sub-cavity. The heating platform 130 and the loading component 140 are located inside the second sub-cavity. The cover 150 has an air inlet 151 and an air outlet 152 on its two side walls opposite to the first sub-cavity. The inert gas flows in from the air inlet 151 and flows out from the air outlet 152 to form a negative pressure at the exhaust port 155, so that the gas flows from the exhaust port 155 to the air outlet 152 and is discharged.

[0085] Specifically, the cover plate includes a cavity with an opening at the bottom. The open end of the cover plate can cover the base 120 and form a sealed cavity with the base 120. A partition 154 is fixedly installed inside the cover plate. The partition 154 and the cover plate can be fixedly connected by welding or other methods. The partition 154 divides the cavity inside the cover plate into a first sub-cavity and a second sub-cavity spaced apart vertically. The first sub-cavity is located above the second sub-cavity. Multiple vent holes 155 are provided in the middle of the partition 154, and each vent hole 155 communicates with the first and second sub-cavities. Furthermore, an air inlet 151 and an air outlet 152 are respectively opened on the two opposite side walls of the first sub-cavity. Inert gas is blown into the first sub-cavity through the air inlet 151 and discharged through the air outlet 152. The inert gas will form a negative pressure at the exhaust port 155. This negative pressure can be used to make the gas generated by the heating and decomposition of alkaline compounds in the second sub-cavity flow out from the exhaust port 155 to the air outlet 152, so as to collect the gas from the air outlet 152 and measure the collected gas.

[0086] It is understood that the vacuum port 153 can be located on the side wall corresponding to the first sub-cavity on the cover 150, or on the side wall corresponding to the second sub-cavity, preferably on the side wall corresponding to the second sub-cavity, and the vacuum port 153 and the air inlet 151 can be located on the same side wall of the cover 150.

[0087] In some embodiments, a pressure sensor is provided at the fixed connection between the support member 113 and the weighing device 110, and the weighing device 110 obtains the mass of the substance to be tested based on the pressure sensor.

[0088] For example, the weighing device 110 is an electronic scale, etc. It converts the mass information of the substance to be measured in the load 140 into an electrical signal through a pressure sensor, and then amplifies and converts the signal into a digital signal, which is finally displayed on the display 115 of the weighing device 110. The weighing device 110 is directly connected to the computer 240 via a network cable or USB cable. The computer 240 records the mass of the substance to be measured and the mass change curve over time and temperature.

[0089] In some implementations, reference Figure 1 and Figure 2 There are multiple support members 113, which are circumferentially distributed on the outer side of the load member 140, and each support member 113 is fixedly connected to the load member 140 through a connector 114.

[0090] Specifically, the support member 113 can be a support rod, and there are at least two support rods, such as 2, 3, 4, etc. Each support rod is circumferentially distributed on the outside of the load member 140, preferably evenly distributed, and provides stable support force to the load member 140 through each support rod. The upper end of each support member 113 is fixedly connected to the side wall of the load member 140 through a connector 114, such as by welding, screwing, riveting, etc. The connector 114 can be a connecting plate, etc. The lower end of each support rod passes through the base 120 and is connected to the weighing platform at the first area 111.

[0091] In some embodiments, a protective sleeve is fitted over the outer side of the support member 113.

[0092] Specifically, the support 113 is fitted with a high-temperature resistant protective sleeve on its outer side, which can be made of ceramic or high-temperature resistant metal, to prevent the support 113 from deforming at high temperatures.

[0093] In some implementations, reference Figures 1 to 3 The heating and decomposition device 100 further includes a cooling pipe 160, which passes through the heating platform 130 and has an inlet 161 and an outlet 162. The inlet 161 and the outlet 162 are used to circulate cooling medium into the cooling pipe 160 so that the cooling pipe 160 and the heating platform 130 can exchange heat.

[0094] Specifically, the cooling pipe 160 is located near the lower end of the heating platform 130. The cooling pipe 160 can circulate cooling medium through the liquid inlet 161 and the liquid outlet 162. The cooling medium includes water, air, liquid nitrogen, etc. The cooling medium can absorb the heat of the heating platform 130, ensuring that the heating platform 130 will not affect the weighing device 110 when heating.

[0095] In some implementations, reference Figure 2 and Figure 3The base 120 has a groove 121 on the side away from the weighing device 110 and located in the first region 111, and the heating table 130 is assembled in the groove 121.

[0096] In some implementations, reference Figure 2 and Figure 3 The heating platform 130 is provided with a heating element 131, which is used to heat the heating platform 130.

[0097] Specifically, the heating element 131 is made of high-temperature resistant material. The heating element 131 can be a resistance wire, etc. The heating stage 130 is heated by controlling the heating of the resistance wire, so as to heat the substance to be tested and decompose the alkaline compound to produce gas.

[0098] In some implementations, reference Figure 2 and Figure 3 The base 120 has slots 122 around its perimeter, and the cover 150 is fitted into the slots 122 so that the cover 150 and the base 120 are sealed together to form the sealed cavity.

[0099] In this example, a slot 122 is formed on the side of the base 120 away from the weighing device 110 along the circumference. The open end of the cover 150 can be fastened into the slot 122, so that the cover 150 and the base 120 cooperate to form a sealed cavity, thereby providing a closed environment for the heating and decomposition of the substance to be tested. A sealing gasket or similar device can also be installed in the slot 122 to increase the sealing performance of the cavity.

[0100] The second aspect of this utility model, with reference to... Figure 8 A substance content determination system is provided, which is used to determine the content of alkaline compounds in the substance to be tested. The system includes: a vacuum pump 200, a gas supply device 210, a mass spectrometer 220, a computer 240, and a heating decomposition device 100 as described in any embodiment of this application. The vacuum pump 200 is connected to the vacuum port 153, the gas supply device 210 is connected to the gas inlet 151, the mass spectrometer 220 is connected to the gas outlet 152, and the signal output terminals of the mass spectrometer 220 and the weighing device 110 are electrically connected to the signal input terminal of the computer 240.

[0101] Specifically, the substance to be tested is placed in the receiving cavity 141 of the carrier 140, and the cover 150 is closed onto the base 120 to form a sealed cavity. The weighing device 110 can obtain the initial mass of the substance to be tested and display it on the display 115. First, the sealed cavity is evacuated by the vacuum pump 200 to ensure that the residual air in the sealed cavity is expelled. Then, inert gas is introduced into the sealed cavity through the gas supply device 210. The heating rate and temperature of the heating stage 130 are controlled to heat the substance to be tested, so that the alkaline compounds in the substance to be tested decompose and produce gas in a vacuum and inert environment. The molar mass of the produced gas can be obtained by the mass spectrometer 220. The weighing device 110 is directly connected to the computer 240 via a network cable or USB cable. The weighing device 110 obtains the mass of the substance to be tested in real time during the heating process, and the computer 240 records the mass change curve of the substance to be tested over time. The mass spectrometer 220 is directly connected to the computer 240 via a network cable or USB cable. The mass spectrometer 220 can acquire the type of each gas and the corresponding peak time and peak end time of the gas. The computer 240 can determine the mass of each type of gas and the mass ratio of each type of gas in the analyte by combining the peak time and peak end time of each type of gas with the mass change curve of the analyte over time.

[0102] It should be noted that the criterion for determining whether the analyte has completely decomposed by heating is as follows: if the mass change value of the analyte obtained by the weigher 110 is less than a preset threshold, then the analyte is determined to have completely decomposed by heating. The preset threshold can be 0.1 mg, 0.01 mg, or other values, which can be set by those skilled in the art according to actual needs; or, if the ion peak of the corresponding gas obtained by the mass spectrometer 220 disappears, it indicates that the analyte has completely decomposed by heating.

[0103] The substance content determination system provided in this application embodiment can decompose alkaline compounds in the test substance under the protection of inert gas to generate gas, avoiding interference from air and other factors on the measurement of alkaline compound content, improving the accuracy of alkaline compound measurement, and having a low detection limit and high sensitivity. It can also realize non-aqueous testing of alkaline compounds in the test substance without affecting the structure, morphology and electrochemical performance of the test substance.

[0104] The specific technical features and effects of the substance content determination system provided in this application embodiment are the same as those of the heating decomposition device 100, and will not be repeated in this application embodiment.

[0105] It is understood that the substance content determination system provided in this application embodiment may also include components such as a temperature sensor. The temperature sensor is disposed within the side wall of the cover 150 corresponding to the second sub-chamber, and is used to acquire the temperature within the sealed cavity. The signal output terminal of the temperature sensor is electrically or wirelessly connected to the signal input terminal of the computer 240, and the signal output terminal of the pressure sensor is also electrically or wirelessly connected to the signal input terminal of the computer 240. The computer 240 is equipped with temperature monitoring software and quality monitoring software. Through the cooperation of the temperature monitoring software and the temperature sensor, the temperature changes within the sealed cavity can be monitored in real time; through the cooperation of the quality monitoring software and the pressure sensor, the mass changes of the substance to be tested can be monitored in real time.

[0106] In some implementations, reference Figure 8 The system also includes a cooling device 230, which is connected to the inlet 161 and outlet 162 of the cooling pipe 160.

[0107] In this example, the cooling device 230 can be a chiller, etc. The chiller circulates cooling water into the cooling pipe 160 through the inlet 161 and outlet 162 to cool the lower end of the heating platform 130 and ensure that the upper end of the heating platform 130 will not affect the balancer 110 when it is heated.

[0108] In some embodiments, the mass spectrometer 220 is used to acquire the elution time and peak end time of various gases, and to send the elution time and peak end time of various gases to the computer 240.

[0109] The weighing device 110 is used to acquire the mass of the substance to be tested in real time and send the acquired mass of the substance to be tested to the computer 240.

[0110] The computer 240 determines the mass change curve of the analyte over time based on the mass of the analyte acquired in real time by the weighing device 110. The computer 240 also determines the mass of the analyte corresponding to the peak elution time and the mass of the analyte corresponding to the peak end time based on the peak elution time and peak end time of various gases acquired by the mass spectrometer 220, and in conjunction with the mass change curve of the analyte over time. Based on the mass loss of the analyte corresponding to the peak elution time and the mass of the analyte corresponding to the peak end time, the computer 240 determines the mass percentage of the gas in the analyte, based on the mass of the gas and the initial mass of the analyte acquired by the weighing device 110, and in conjunction with the heating decomposition equation of the analyte, determines the mass percentage of the alkaline compound in the analyte.

[0111] Specifically, the mass spectrometer 220 is used to obtain the molar mass, peak elution time, and peak end time of various gases to ensure the comprehensiveness and accuracy of gas detection. Among these, the molar mass of the gas can be used for gas type identification.

[0112] For example, the substance to be tested is a positive electrode material, which includes the alkaline compounds Li₂CO₃ and LiOH. The initial mass of the positive electrode material obtained by the weighing device 110 is m₀. Under the protection of an inert gas, the Li₂CO₃ and LiOH on the surface of the positive electrode material decompose. The heating decomposition equation of Li₂CO₃ is: Li₂CO₃ = Li₂O + CO₂↑; the heating decomposition equation of LiOH is: 2LiOH = Li₂O + H₂O↑. The CO2 and H2O generated by the heating and decomposition of the cathode material enter the mass spectrometer 220 under the purging of the gas supply device 210. When the mass spectrometer 220 captures CO2 and H2O, it indicates that Li2CO3 and LiOH on the surface of the cathode material have begun to decompose and produce CO2 and H2O. When the ion peaks of CO2 and H2O disappear, it indicates that the decomposition is over. The mass spectrometer 220 can capture the start and end times of CO2 elution. Combined with the time-varying curve of the analyte obtained by the computer 240, the mass m of CO2 can be obtained by using the difference between the mass of the analyte at the start of CO2 elution and the mass loss of the analyte at the end of the peak. CO2 Then calculate the mass percentage W of CO2 in the initial mass of the analyte. CO2 =m CO2 / m0. Based on the thermal decomposition equation of Li2CO3, the mass percentage of Li2CO3 in the cathode material is obtained as W. Li2CO3 =W CO2 ×73.89 / 44=m CO2 ×73.89 / (44×m0)

[0113] Similarly, the mass spectrometer 220 can capture the start and end times of H2O elution. Combined with the time-varying curve of the analyte acquired by the computer 240, the mass m of H2O can be obtained by using the difference between the mass of the analyte at the start and end times of H2O elution. H2O Then calculate the mass percentage W of H2O in the initial mass of the analyte. H2O =m H2O / m0. Based on the thermal decomposition equation of LiOH, the mass percentage of LiOH in the cathode material is obtained as W. LiOH =W H2O ×2×23.95 / 18 =m H2O ×2×23.95 / (18×m0).

[0114] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A heating decomposition apparatus (100), characterized in that, include: The weighing device (110) includes a weighing platform having a first weighing area (111) and a second area (112) located outside the first area (111). A base (120) is disposed above the weighing platform and is fixedly connected to the weighing device (110) in the second region (112). A heating platform (130) is disposed on the base (120) in the first region (111). A carrier (140) is disposed above the heating stage (130). The carrier (140) has a receiving cavity (141) for placing the substance to be tested. The heating stage (130) is used to heat the substance to be tested so that the substance to be tested decomposes to produce at least one gas. A support member (113) is fixed on the carrier (140). The support member (113) passes through the base (120) and is fixedly connected to the weighing device (110) at the first region (111). The weighing device (110) is used to obtain the mass and mass change of the substance to be tested. A cover (150) is fitted onto the base (120) and forms a sealed cavity with the base (120). The cover (150) is provided with an air inlet (151), an air outlet (152), and a vacuum port (153) communicating with the sealed cavity. The vacuum port (153) is used to evacuate the sealed cavity. The air inlet (151) is used to introduce inert gas into the sealed cavity so that the substance to be tested decomposes under the protection of the inert gas to produce at least one gas. The air outlet (152) is used to discharge each of the gases.

2. The heating decomposition apparatus (100) according to claim 1, characterized in that, The heating platform (130) has a heating plane on the side away from the base (120), and the heating plane is in contact with the carrier (140); Alternatively, the heating platform (130) may have an assembly groove on the side away from the base (120), and the load (140) may extend at least partially into the assembly groove.

3. The heating decomposition apparatus (100) according to claim 1, characterized in that, The cover (150) includes a cavity with a bottom opening. A partition (154) is provided in the cavity. The partition (154) divides the cavity into a first sub-cavity and a second sub-cavity that are spaced apart vertically. A plurality of vent holes (155) are provided on the partition (154). The vent holes (155) are connected to the first sub-cavity and the second sub-cavity. The first sub-cavity is located above the second sub-cavity. The heating platform (130) and the loading device (140) are located inside the second sub-cavity. The cover (150) has an air inlet (151) and an air outlet (152) on its two side walls opposite to the first sub-cavity. The inert gas flows in from the air inlet (151) and flows out from the air outlet (152) to form a negative pressure at the exhaust port (155) so that the gas flows out from the exhaust port (155) to the air outlet (152).

4. The heating decomposition apparatus (100) according to claim 1, characterized in that, A pressure sensor is provided at the fixed connection between the support member (113) and the weighing device (110), and the weighing device (110) obtains the mass of the substance to be tested based on the pressure sensor.

5. The heating decomposition apparatus (100) according to claim 1, characterized in that, There are multiple support members (113), which are circumferentially distributed on the outside of the load (140), and each support member (113) is fixedly connected to the load (140) through a connector (114).

6. The heating decomposition apparatus (100) according to claim 5, characterized in that, The support (113) is covered with a protective sleeve on its outer side.

7. The heating decomposition apparatus (100) according to claim 1, characterized in that, The heating and decomposition device (100) further includes a cooling pipe (160) that passes through the heating platform (130) and has an inlet (161) and an outlet (162) for circulating cooling medium into the cooling pipe (160) to facilitate heat exchange between the cooling pipe (160) and the heating platform (130).

8. The heating decomposition apparatus (100) according to claim 1, characterized in that, The base (120) is provided with a groove (121) on the side away from the weighing device (110) and located in the first region (111), and the heating table (130) is assembled in the groove (121).

9. The heating decomposition apparatus (100) according to claim 1, characterized in that, The heating platform (130) is provided with a heating element (131), which is used to heat the heating platform (130).

10. The heating decomposition apparatus (100) according to claim 1, characterized in that, The base (120) has slots (122) around its perimeter, and the cover (150) is fitted into the slots (122) so that the cover (150) and the base (120) are sealed together to form the sealed cavity.

11. A substance content determination system, characterized in that, The system is used to determine the content of alkaline compounds in the analyte, and the system includes: The device comprises a vacuum pump (200), a gas supply device (210), a mass spectrometer (220), a computer (240), and a heating decomposition apparatus (100) according to any one of claims 1-10. The vacuum pump (200) is connected to the vacuum port (153), the gas supply device (210) is connected to the gas inlet (151), the mass spectrometer (220) is connected to the gas outlet (152), and the signal output terminals of the mass spectrometer (220) and the weighing device (110) are electrically connected to the signal input terminal of the computer (240).

12. The substance content determination system according to claim 11, characterized in that, The system also includes a cooling device (230), which is connected to the inlet (161) and outlet (162) of the cooling pipe (160).

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