Wide-temperature-range electrochemical in-situ infrared spectrum testing device based on attenuated total reflection mode

Abstract

The invention provides a wide-temperature-range electrochemical in-situ infrared spectrum testing device based on an attenuated total reflection mode, which comprises a pool body, a shell, an ATR prism, a sealing ring, a temperature control assembly and a temperature sensor, the pool body is provided with a working surface, and the working surface is concavely provided with a reaction tank; the cell body is made of a metal material and can be used as a counter electrode current collector; the ATR prism is connected to the working surface of the cell body, the ATR prism is provided with a top surface opposite to the working surface, and the top surface is provided with a metal coating; the metal coating can be used as a working electrode current collector; the sealing ring is installed between the pool body and the ATR prism, the whole structure is compact, the cost is low, the thermal inertia is small, the good temperature control capacity is achieved, rapid response to temperature changes can be achieved, and the in-situ infrared testing device is suitable for the in-situ infrared testing requirement under the wide-temperature-range variable-temperature condition.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical spectroscopy, in particular to a wide-temperature-range electrochemical in-situ infrared spectroscopy testing device based on an attenuated total reflection mode. Background Art

[0002] To address the climate and energy crises and achieve my country's "dual carbon" goals, renewable energy sources such as photovoltaics and wind power are gaining attention. However, the intermittent nature and uneven spatial distribution of renewable energy sources are key bottlenecks hindering their large-scale application. For example, photovoltaic power generation is only effective during daylight hours and cannot match the peaks and valleys in electricity demand at night. Therefore, energy storage technology has become a core challenge in the energy transition. Among various energy storage technologies, electrochemical energy storage stands out due to its fast response speed (milliseconds), environmental friendliness, and modular deployment flexibility. Among them, lithium-ion batteries (LIBs) have become the mainstream choice due to their high energy density (250-300 Wh / kg), long life (>2000 cycles), and mature commercial applications.

[0003] Despite their widespread use, lithium-ion batteries experience significant performance degradation at extreme temperatures (e.g., below 0°C or above 50°C), posing safety risks. As human activities expand into polar regions, the deep ocean, and outer space, the market urgently demands high-performance batteries that can operate stably over a wide temperature range. Developing such batteries has become a strategic priority for energy storage technology innovation, but the technical bottleneck lies in understanding and addressing the degradation and even failure of batteries at extreme temperatures.

[0004] The performance of batteries over a wide temperature range depends largely on the electrode / electrolyte interface. Electrochemical in situ infrared spectroscopy is a powerful tool for real-time monitoring of changes in this interface. By monitoring molecular vibrations at the electrode / electrolyte interface in real time, it provides a key tool for revealing the evolution of interfacial molecular structure, intermediate generation, and dynamic reaction pathways, helping us analyze the effect of temperature on electrode / electrolyte interface processes. However, conventional electrochemical in situ infrared spectroscopy equipment can usually only be tested at room temperature and cannot characterize electrode / electrolyte interface processes under wide temperature conditions.

[0005] Most existing infrared spectrometers lack built-in temperature control systems. To meet variable temperature requirements, optical path accessories must be modified, or the entire instrument must be placed in a variable-temperature environmental chamber. This is costly, lacks compatibility with infrared spectrometers from different manufacturers, and is inconvenient to operate over a wide temperature range, potentially damaging the instrument. Furthermore, some existing electrochemical in-situ spectroscopy devices that can operate within a limited temperature range suffer from large size.

[0006] Therefore, there is an urgent need to develop an electrochemical in-situ infrared test cell that is low-cost, highly versatile, and can precisely control temperature. Summary of the Invention

[0007] To this end, in order to address at least one of the above problems, the present invention provides a wide-temperature-range electrochemical in-situ infrared spectroscopy testing device based on an attenuated total reflection mode.

[0008] The present invention is implemented by the following scheme: The present invention proposes a wide-temperature-range electrochemical in-situ infrared spectroscopy testing device based on attenuated total reflection mode, comprising: A cell body having a working surface with a reaction groove recessed thereon; the cell body is made of metal and can serve as a current collector for the counter electrode; An ATR prism, the ATR prism being connected to the working surface of the cell body, the ATR prism having a top surface disposed opposite to the working surface, the top surface being provided with a metal coating; the metal coating being capable of serving as a working electrode current collector; A sealing ring is installed between the cell body and the ATR prism, and is arranged around the periphery of the reaction tank. The sealing ring can seal the gap between the cell body and the ATR prism, thereby providing a reaction chamber; A temperature control component, the temperature control component is attached to the pool body; A housing having a hollow structure for mounting the cell body and the temperature control assembly therein; and A temperature sensor is used to monitor the temperature of the cell body.

[0009] In one embodiment, the ATR prism is a three-dimensional structure with an inverted trapezoidal cross-section, and the ATR prism further includes a bottom surface, a light incident surface, a light emitting surface, and two side surfaces.

[0010] In one embodiment, the ATR prism is mounted on the working surface of the pool body through a prism bracket, and the prism bracket includes a flange, one side of the flange is connected to a first side panel and a second side panel, and the lower ends of the first side panel and the second side panel are connected through a bottom plate, thereby forming a prism mounting cavity in the prism bracket, and the prism mounting cavity has a first opening and a second opening, which correspond to the light incident surface and the light exit surface of the ATR prism, respectively.

[0011] In one embodiment, the prism bracket is made of metal; the flange is provided with screw holes for passing screws to install and connect the prism bracket to the working surface of the pool body; and insulating material is provided inside and around the screw holes.

[0012] In one embodiment, the insulating material is PEEK material.

[0013] In one embodiment, the material of the ATR prism is ZnSe.

[0014] In one embodiment, the temperature control component includes a TEC heating and cooling plate, and the TEC heating and cooling plate is arranged close to the pool body; the temperature control component also includes a heat dissipation copper bar, and the heat dissipation copper bar is provided with a cooling fluid channel.

[0015] In one embodiment, the temperature sensor is a PT100 thermistor, a sensor mounting hole is provided on one side of the cell body, and the temperature sensor is embedded in the cell body through the sensor mounting hole.

[0016] In one embodiment, the shell includes a first half shell and a second half shell connected to each other, the first half shell is provided with a mounting groove, the mounting groove is used to install the pool body, and the bottom of the mounting groove is provided with an opening; the pool body is provided with a boss, the boss protrudes and fits into the opening, and the working surface of the pool body is flush with the lower surface of the first half shell.

[0017] In one embodiment, the metal plating layer is a gold plating layer; and / or the cell body is made of stainless steel 316L.

[0018] The technical solution provided by the present invention has the following technical effects: 1. The present invention proposes a wide-temperature-range electrochemical in-situ infrared spectroscopy testing device based on an attenuated total reflection mode, comprising a cell body, a shell, an ATR prism, a sealing ring, a temperature control component, and a temperature sensor. The cell body has a working surface with a reaction groove recessed on the working surface; the cell body is made of metal and can serve as a counter electrode current collector; the ATR prism is connected to the working surface of the cell body, and the ATR prism has a top surface arranged opposite to the working surface, and the top surface is provided with a metal coating; the metal coating can serve as a working electrode current collector; the sealing ring is installed between the cell body and the ATR prism. The overall structure is compact, the cost is low, the thermal inertia is small, and it has good temperature control capability. It can achieve rapid response to temperature changes and is suitable for in-situ infrared testing requirements under variable temperature conditions in a wide temperature range.

[0019] 2. The ATR prism is made of zinc selenide (ZnSe). ZnSe prisms have good temperature stability and are highly transparent in a wide infrared range. They have a relatively high refractive index and a low absorption coefficient, which can ensure the effective transmission of infrared light and improve the analytical accuracy of the device. Their good mechanical strength and thermal shock resistance make them more suitable for electrochemical in-situ infrared spectroscopy test devices with a wide temperature range.

[0020] 3. The temperature control component includes a TEC heating and cooling plate and a heat dissipation copper bar. The heat dissipation copper bar is provided with a cooling fluid channel for promoting heat exchange, through which cooling water flows, thereby achieving high-power rapid temperature change, thereby forming a semiconductor temperature-controlled and variable-temperature electrochemical in-situ infrared cell body with an integrated water cooling system.

[0021] 4. The ATR prism is mounted and connected to the working surface of the cell body through a prism bracket. The prism bracket includes a flange. The flange is provided with screw holes for passing screws to mount the prism bracket on the working surface of the cell body. Insulating material is provided inside and around the screw holes to prevent short circuits between electrodes, making the device safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a three-dimensional diagram of an infrared spectrum testing device according to an embodiment of the present invention; Figure 2 is an exploded view of the infrared spectrum testing device of this embodiment; Figure 3 is a partially cutaway perspective view of the infrared spectrum testing device of this embodiment; Figure 4 is a perspective view of the cell body of this embodiment; Figure 5 is a perspective view of the first half shell of this embodiment; Figure 6 is a perspective view of the ATR prism of this embodiment; Figure 7 is a full cross-sectional view of the ATR prism of this embodiment; Figure 8 is a perspective view of the prism holder of this embodiment; Figure 9 is a three-dimensional view of the prism bracket of the embodiment from another direction; Figure 10 The blank prism at 20 ℃ is used as the background to compare the infrared spectra of blank samples collected by Si and ZnSe prisms at -20 ℃ with the infrared spectra of electrolyte collected at 20 ℃. Figure 11 The results of the pool temperature control test are shown in Figure (a), where Figure (b) shows a test at 30 to 70°C; Figure (a) shows a test at -20 to 17°C. Figure 12 This is an infrared spectrum diagram of the infrared spectrum testing device of this embodiment testing 1 M LiFSI DME electrolyte in the range of -20 to 70°C. DETAILED DESCRIPTION

[0023] To further illustrate various embodiments, the present invention is provided with accompanying drawings. These drawings form part of the present disclosure and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, one of ordinary skill in the art will understand other possible embodiments and the advantages of the present invention. The components in the figures are not drawn to scale, and similar reference numerals are generally used to represent similar components.

[0024] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1-12 As shown, this embodiment provides a wide temperature range electrochemical in-situ infrared spectroscopy testing device 1 based on attenuated total reflection mode, including a cell body 10, a shell 20, an ATR prism 30, a sealing ring 40, a temperature control component 50, a prism bracket 60 and a temperature sensor 70.

[0026] The housing 20 comprises a first half-shell 21 and a second half-shell 22, which are connected to each other, for example, by screws, to form the housing 20. The housing 20 is a hollow structure, which houses the tank 10 and the temperature control assembly 50. The temperature control assembly 50 is attached to the tank 10 and is used to regulate the temperature of the tank 10.

[0027] The temperature control assembly 50 includes a TEC heating and cooling plate 51, which is positioned adjacent to the cell body 10. The TEC heating and cooling plate 51 is a semiconductor temperature controller. Semiconductor temperature control is based on the Peltier effect. When a direct current passes through a semiconductor thermocouple pair, electrons move from the N-type semiconductor to the P-type semiconductor, while holes move in the opposite direction, resulting in heat absorption (cold end) and heat release (hot end) at the junction. This method is suitable for in-situ testing scenarios with a temperature range of -20°C to 60°C and the need for rapid temperature changes. However, its cooling efficiency decreases significantly with increasing temperature differences, requiring water or air cooling to maintain stable performance during high-power operation. Based on the above considerations, the temperature control assembly 50 of this embodiment further includes a heat dissipation copper busbar 52, which is equipped with cooling fluid channels 521 and 522 to facilitate heat exchange, such as channels for cooling water. This allows for rapid high-power temperature changes, thereby forming a semiconductor-controlled, variable-temperature electrochemical in-situ infrared cell with an integrated water cooling system. In this embodiment, TEC heating and cooling plates are used for temperature control. Compared with traditional fluid circulation temperature control, this embodiment has a faster temperature change speed, a simple system, and occupies a small volume.

[0028] The cell body 10 is also equipped with a temperature sensor 70, which can be embedded in the cell body 10 through a sensor mounting hole 13 on one side of the cell body 10. The temperature sensor 70, for example, is a PT100 thermistor, which monitors the temperature of the cell body in real time. The first half shell 21 is provided with a through hole 213 for passing the temperature sensor 70 and its leads. The PT100 thermistor is encased in a polytetrafluoroethylene sleeve to prevent any electrical interference from the thermistor.

[0029] The first half shell 21 is provided with a mounting groove 212 for mounting the tank body 10. The bottom of the mounting groove 212 is provided with an opening 211, and the tank body 10 at least partially protrudes into the opening 211. Preferably, the tank body 10 is provided with a boss 11, which protrudes and fits into the opening 211, and the working surface 12 of the tank body 10 is flush with the lower surface of the first half shell 21. Figure 3 As shown, the working surface 12 of the cell body 10 is recessed with a reaction groove 15, which can serve as a chamber that at least partially contains the electrochemical reaction material. The ATR prism 30 is mounted and connected to the working surface 12 of the cell body 10 via a prism bracket 60. A sealing ring 40 is installed between the cell body 10 and the ATR prism 30. The sealing ring 40 is arranged around the periphery of the reaction groove 15 and can seal the gap between the cell body 10 and the ATR prism 30, thereby providing a sealed reaction chamber 80.

[0030] The reaction chamber 80 includes a reaction tank 15, and the reaction chamber 80 is used to accommodate battery components; more specifically, the reaction chamber 80 is used to accommodate the counter electrode, the diaphragm, the working electrode and the electrolyte. The cell body 10 is made of metal, so that the cell body 10 is in contact with the counter electrode and electrically connected. The cell body 10 also serves as a counter electrode current collector, and plays the role of conducting the counter electrode current. The cell body 10 is connected to the counter electrode wire 101, which serves as a lead-out wire for the counter electrode. The top surface 31 of the ATR prism 30 is provided with a metal coating 301, wherein the top surface 31 is arranged opposite to the working surface 12, and the metal coating 301 is attached to the working electrode piece and electrically connected; the metal coating 301 can serve as a working electrode current collector to conduct current to the external circuit.

[0031] In this embodiment, the metal coating 301 is specifically a gold-plated layer, which provides excellent electrical conductivity. The gold-plating process is mature and reliable, and the gold-plated layer can also enhance the infrared spectrum, thereby increasing the observed infrared spectrum intensity. The cell body 10 is specifically made of 316L stainless steel, which is not easily reactive with other chemicals and has stable performance.

[0032] Conventional in-situ Fourier transform infrared spectroscopy (FTIR) test modes include: external reflection (thin layer mode) and internal reflection (attenuated total reflection mode). The thin layer mode relies on the formation of a thin layer of electrolyte between the electrode surface and the infrared window to reduce the interference of excessive infrared absorption of the bulk electrolyte on the acquisition of infrared signals at the interface. Generally, the thin layer solution is 1 to 10 μm thick. Due to the presence of the thin layer electrolyte, the solution resistance increases, the mass transfer resistance increases, resulting in a slow potential response speed (about tens of milliseconds). At the same time, the species are easily depleted, and there are problems such as uneven current density distribution on the electrode surface. In this embodiment, the internal reflection (attenuated total reflection) mode is used to cause the infrared light to be totally reflected on the prism test surface, and the test is performed through the latent vector wave. Therefore, there is no need to form a thin layer, which overcomes the above-mentioned problems of the thin layer mode.

[0033] The ATR prism 30 is an attenuated total reflection (ATR) prism. It is a three-dimensional structure with an inverted trapezoidal cross-section, comprising a top surface 31, a bottom surface 34, a light-incident surface 32, a light-exiting surface 33, and two side surfaces 35. The top surface 31 of the ATR prism 30 is larger than the bottom surface 34. Because the top surface 31 of the ATR prism 30 is coated with a metal coating 301, infrared light enters the ATR prism 30 through the light-incident surface 32 and irradiates the reaction chamber 80. At appropriate angles of incidence, the infrared light undergoes attenuated total reflection within the ATR prism 30 and exits through the light-exiting surface 33. When the sample in the reaction chamber 80 is exposed to infrared light of continuously varying frequencies, the molecules absorb some of the radiation, causing vibrations or rotations to change the molecular dipole moment. This causes transitions in vibrational and rotational energy levels from the ground state to excited states, resulting in a molecular absorption spectrum. By analyzing the infrared absorption spectrum of the emitted infrared light, it is possible to perform group structure analysis of the material and qualitative and quantitative analysis of the material.

[0034] The ATR prism 30 is used to ensure efficient transmission of infrared light. In this embodiment, the material of the ATR prism 30 is zinc selenide (ZnSe). However, this is not limiting. In other embodiments, the ATR prism 30 may also be made of Si prism material.

[0035] In order to evaluate the stability of different ATR prism materials under variable temperature conditions and the reliability of sample testing, ATR prisms made of Si and ZnSe were tested. The test band of Si prism is 4000-1000 cm -1 , ZnSe prism is 4000-650 cm -1 The spectral resolution is 4 cm -1 .

[0036] First, single-beam spectra of a blank prism were collected at 20°C and -20°C. Using the 20°C spectrum as a reference, the transmission spectra of the Si and ZnSe prisms at a 40°C temperature difference were obtained using the difference spectrum method. The intensity changes in the resulting spectra can be used to assess the prism material's response to temperature changes, thereby determining its impact on the stability of infrared spectral acquisition.

[0037] In addition, single-beam spectra of the electrolyte samples were collected through Si and ZnSe prisms at 20 ° C, and the blank prism spectrum under the same conditions was used as a reference for difference spectrum processing to obtain the electrolyte transmission spectra of Si and ZnSe prisms at room temperature. The electrolyte used was 1 M LiFSI DME electrolyte, which is an electrolyte with a concentration of 1 mol / L prepared by dissolving bis(fluorosulfonyl)imide in lithium salt (LIFSI) in ethylene glycol dimethyl ether (DME) solvent. By comparing the spectral results obtained by the same prism under different temperature conditions, the influence of prism temperature change on the reliability of sample testing is analyzed. The experimental results are shown in Figure 2. Figure 10 shown.

[0038] from Figure 10 As can be seen from the figure, Si prism has a wavelength of 1500-1000 cm -1 The band is more sensitive to temperature changes, and this region corresponds to its inherent absorption peak. At a temperature difference of 40°C, the maximum intensity change of the Si prism is about twice the sample signal intensity, which seriously interferes with the normal detection of the sample. In contrast, the ZnSe prism shows good temperature stability, with a peak intensity of 760-650cm -1 The maximum intensity variation within the band is only 0.1 (relative intensity), and this variation does not affect the accurate identification of the sample signal. Therefore, in this embodiment, after precise experimental analysis, zinc selenide (ZnSe) was selected as the material for ATR prism 30 due to its excellent temperature stability. ZnSe prisms are highly transparent across a wide infrared range, have a relatively high refractive index, and a low absorption coefficient, ensuring efficient transmission of infrared light and improving the analytical accuracy of the device. Their excellent mechanical strength and thermal shock resistance make them particularly suitable for electrochemical in-situ infrared spectroscopy testing devices operating over a wide temperature range.

[0039] As mentioned above, the ATR prism 30 is mounted on the working surface 12 of the cell body 10 via the prism bracket 60. Figure 8-Figure 9 The prism holder 60 includes a flange 61, one side of which is connected to a first side plate 62 and a second side plate 63. The lower ends of the first side plate 62 and the second side plate 63 are connected by a bottom plate 64, thereby forming a prism mounting cavity 65 in the prism holder 60. The prism mounting cavity 65 has a first opening 651 and a second opening 652, which correspond to the light incident surface 32 and the light exit surface 33 of the ATR prism 30, respectively.

[0040] The flange 61 is provided with screw holes 67 for inserting screws to install and connect the prism bracket 60 to the working surface 12 of the cell body 10. The working surface 12 of the cell body 10 is provided with threaded holes 14 for connection with the screws. The prism bracket 60 is usually made of metal material. However, since the metal coating 301 on the ATR prism 30 can serve as a working electrode current collector to conduct current to the external circuit; if it is connected to the cell body 10 as the counter electrode current collector by a metal screw, a short circuit between the electrodes is likely to occur and testing cannot be performed. In this embodiment, insulating material is provided inside and around the screw hole 67 to achieve insulation between the electrodes, which is convenient for subsequent testing. In this embodiment, the insulating material inside and around the screw hole 67 is PEEK material. PEEK material is an ideal electrical insulator. It can still maintain good electrical insulation performance under harsh working conditions such as high temperature, high pressure and high humidity, and the device is safer.

[0041] Preferably, the housing 20 is made of a heat-insulating material, such as PEEK material, so that the device has less heat exchange with the outside world and the temperature control is more precise and stable.

[0042] In addition, in order to reduce the interference of water vapor condensation on infrared spectrum acquisition under low temperature conditions, an air compressor was introduced into the system for dehumidification, which effectively improved the signal quality and test stability.

[0043] The wide temperature range electrochemical in-situ infrared spectroscopy testing device 1 based on attenuated total reflection mode provided in this embodiment has a compact overall structure, low cost, and low thermal inertia through the above design. The temperature regulation stability of the device is tested using the PID control algorithm. The experimental results are as follows: Figure 11 As shown. Figure 11 As can be seen in the figure, the device can stably reach 70°C at high temperatures with a relatively fast heating rate; at low temperatures, it can reach as low as -20°C with good temperature control accuracy. In summary, the system has excellent temperature control capabilities and can quickly respond to temperature changes, making it suitable for in-situ infrared testing under variable temperature conditions over a wide temperature range.

[0044] The wide temperature range electrochemical in-situ infrared spectroscopy test device 1 provided in this embodiment was used to test the infrared spectrum of 1 M LiFSI DME electrolyte in the range of -20 to 70 °C. The test results are as follows: Figure 12 The test curve is smooth overall with low noise level, indicating that the platform can effectively meet the infrared testing requirements under different temperature conditions.

[0045] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A wide temperature range electrochemical in-situ infrared spectroscopy testing device based on attenuated total reflection mode, characterized in that: include: A cell body having a working surface with a reaction groove recessed thereon; the cell body is made of metal and can serve as a current collector for the counter electrode; An ATR prism, the ATR prism being connected to the working surface of the cell body, the ATR prism having a top surface disposed opposite to the working surface, the top surface being provided with a metal coating; the metal coating being capable of serving as a working electrode current collector; A sealing ring is installed between the cell body and the ATR prism, and is arranged around the periphery of the reaction tank. The sealing ring can seal the gap between the cell body and the ATR prism, thereby providing a reaction chamber; A temperature control component, the temperature control component is attached to the pool body; A housing, the housing being a hollow structure for mounting the cell body and the temperature control assembly therein; as well as A temperature sensor is used to monitor the temperature of the cell body.

2. The testing device according to claim 1, wherein: The ATR prism is a three-dimensional structure with an inverted trapezoidal cross section. The ATR prism further includes a bottom surface, a light incident surface, a light emitting surface, and two side surfaces.

3. The testing device according to claim 2, wherein: The ATR prism is mounted on the working surface of the pool body through a prism bracket. The prism bracket includes a flange. One side of the flange is connected to a first side panel and a second side panel. The lower ends of the first side panel and the second side panel are connected through a bottom plate, thereby forming a prism mounting cavity in the prism bracket. The prism mounting cavity has a first opening and a second opening, which correspond to the light incident surface and the light exit surface of the ATR prism, respectively.

4. The testing device according to claim 3, wherein: The prism bracket is made of metal material; the flange is provided with screw holes for passing screws to install and connect the prism bracket to the working surface of the pool body; insulating material is provided inside and around the screw holes.

5. The testing device according to claim 4, characterized in that: The insulating material is PEEK material.

6. The testing device according to claim 1, wherein: The material of the ATR prism is ZnSe.

7. The testing device according to claim 1, wherein: The temperature control component includes a TEC heating and cooling plate, and the TEC heating and cooling plate is arranged close to the pool body; the temperature control component also includes a heat dissipation copper bar, and the heat dissipation copper bar is provided with a cooling fluid channel.

8. The testing device according to claim 1, wherein: The temperature sensor is a PT100 thermistor. A sensor mounting hole is provided on one side of the cell body, and the temperature sensor is embedded in the cell body through the sensor mounting hole.

9. The testing device according to claim 1, wherein: The shell includes a first half shell and a second half shell connected to each other. The first half shell is provided with a mounting groove, which is used to install the pool body. The bottom of the mounting groove is provided with an opening; the pool body is provided with a boss, which protrudes and fits into the opening, and the working surface of the pool body is flush with the lower surface of the first half shell.

10. The testing device according to claim 1, wherein: The metal plating layer is a gold plating layer; and / or the cell body is made of stainless steel 316L.

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