Testing device and testing method for battery diaphragm

Abstract

The invention discloses a battery diaphragm testing device and method, the battery diaphragm testing device comprises a reaction system, the reaction system comprises a shell, two reaction frames and a to-be-tested diaphragm material, the to-be-tested diaphragm material is located between the two reaction frames, the shell is located on the side, away from the to-be-tested diaphragm material, of each reaction frame, and the shell is located on the side, away from the to-be-tested diaphragm material, of each reaction frame; the reaction frame is provided with a middle hollow part, and the middle hollow part is used for accommodating a reaction solution; the circulating system is used for providing a reaction solution for the reaction system and receiving the reaction solution flowing out of the reaction system; and the temperature control system is used for detecting the reaction temperature of the reaction solution when the testing device works and keeping the reaction temperature at the target temperature. The testing device is simple, only one reaction chamber is involved, the influence of degradation of other assemblies on the testing result is avoided, the problem that the reaction is insufficient due to the fact that the battery diaphragm is directly soaked in the reaction solution is also avoided, and the error of the testing result is further reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a testing device and a testing method for a battery separator. Background Art

[0002] All-vanadium liquid flow batteries (abbreviated as vanadium batteries) use vanadium ions of different valence states as positive and negative active materials, and realize the storage and release of electrical energy through the valence transformation of vanadium ions. With the advantages of high safety, long service life and low maintenance cost, it has become one of the preferred technical solutions in the field of large-scale energy storage. The diaphragm is one of the key components of the all-vanadium liquid flow battery, which greatly affects the battery's coulombic efficiency, energy efficiency, self-discharge time and cycle life. At present, the most widely used diaphragm in all-vanadium liquid flow batteries is a perfluorosulfonic acid cation exchange membrane, which has high proton conductivity and excellent mechanical stability. During the actual operation of the battery, the vanadium battery diaphragm will be in long-term contact with strongly acidic sulfuric acid (H2SO4) and oxidizing pentavalent vanadium (VO2 + ), hydroxyl radicals (·OH), therefore, the ability to exist stably for a long time in a strong acid and strong oxidizing environment is a necessary condition for the all-vanadium redox flow battery membrane.

[0003] At present, the method for testing the oxidation stability of membranes in vanadium batteries is to immerse the membrane directly in VO2 + In the electrolyte, the valence state of vanadium ions in the electrolyte is monitored for a long time using an ultraviolet spectrophotometer, and the valence change of vanadium ions indirectly reflects the oxidation stability of the membrane. This method directly immerses the membrane in the electrolyte, which is closer to the working environment of the membrane, but due to the VO2 + Because perfluorosulfonic acid membranes are less oxidizing, this method requires a long testing time (typically about a month). Consequently, the test results are often undervalued, which can lead to errors. Furthermore, this method involves battery assembly and testing, making the overall testing process more cumbersome. The degradation of components such as the battery plates in the electrolyte can also affect the test results. Summary of the Invention

[0004] To solve the above technical problems, the present application provides a battery separator testing device and testing method. The specific technical solutions are as follows:

[0005] In the first aspect, the present application provides a testing device for a battery separator, comprising: a reaction system, the reaction system comprising an outer shell, two reaction frames and a membrane material to be tested, the membrane material to be tested being located between the two reaction frames, the outer shell being located on the side of each reaction frame away from the membrane material to be tested, wherein the reaction frame has a middle hollow portion, and the middle hollow portion is used to accommodate a reaction solution; a circulation system for providing the reaction solution to the reaction system and receiving the reaction solution flowing out of the reaction system; and a temperature control system for detecting the reaction temperature of the reaction solution and maintaining the reaction temperature at a target temperature when the testing device is working.

[0006] Optionally, the reaction frame further has a frame portion, which is located around the middle hollow portion. A plurality of first holes are provided on the side of the frame portion, and a plurality of second holes are provided on the outer shell. The plurality of first holes correspond to the plurality of second holes, and the first holes and the second holes are suitable for passing bolts to connect and fix the reaction frame and the outer shell.

[0007] Optionally, a sealing line is further included, which is arranged on the reaction frame. The sealing line is located on the side of the reaction frame that contacts the film material to be tested and is located at the junction of the frame portion and the middle hollow portion. The sealing line is used to seal the film material to be tested and the reaction frame.

[0008] Optionally, the two reaction frames respectively have a first sealing line and a second sealing line, and in the reaction system, the projections of the first sealing line and the second sealing line on the film material to be tested do not overlap.

[0009] Optionally, the circulation system includes a peristaltic pump, a liquid storage tank, a liquid inlet pipe and a liquid outlet pipe; wherein, the liquid storage tank is used to accommodate the reaction solution, one end of the liquid inlet pipe and the liquid outlet pipe are both inserted into the liquid storage tank, the other end of the liquid inlet pipe is inserted into the reaction system, and the other end of the liquid outlet pipe is inserted into the reaction system; the peristaltic pump is arranged on the liquid inlet pipe, and the peristaltic pump is used to make the reaction solution circulate between the liquid storage tank and the reaction system.

[0010] Optionally, the circulation system further includes a defoaming device, which includes a bracket and an agitator. The top of the agitator is fixed on the bracket, and the agitating part of the agitator is located in the liquid storage tank.

[0011] Optionally, the material of the liquid storage tank includes borosilicate glass; and / or the material of the liquid inlet pipe and the liquid outlet pipe includes polypropylene respectively; and / or the material of the agitator includes polytetrafluoroethylene.

[0012] Optionally, the temperature control system includes a constant temperature heater, which is used to heat the reaction solution in the liquid storage tank and maintain the reaction temperature of the reaction solution at the target temperature.

[0013] Optionally, the temperature control system also includes a temperature sensor, and a third hole is provided on the top of any reaction frame, the third hole is used to place the temperature sensor, and the temperature sensing probe of the temperature sensor is suitable for entering the middle hollow part of the reaction frame, wherein the temperature sensor has a protective shell, and the material of the protective shell is polypropylene.

[0014] Optionally, the material of the membrane to be tested is a perfluorosulfonic acid proton exchange membrane, and / or the material of the shell and the reaction frame are both polytetrafluoroethylene.

[0015] Optionally, the reaction solution is a Fenton reagent, which includes 2% to 4% H2O2 and 1.2 mmol / L to 3.9 mmol / L Fe 2+ .

[0016] In a second aspect, the present application also provides a method for testing a battery separator, the method comprising:

[0017] The membrane material to be tested is placed in the reaction system of the testing device; the temperature control system of the testing device is started to heat the reaction solution, and the circulation system of the testing device is started to allow the reaction solution to enter the reaction system and react with the membrane material to be tested; the reaction temperature of the reaction solution is detected by the temperature control system, and when the reaction temperature reaches the set temperature, a specified amount of the reaction solution is extracted as the initial reaction solution, and the absorbance of the initial reaction solution is measured to obtain the initial absorbance; when the reaction time reaches the set time, the temperature control system is stopped, a specified amount of the reaction solution is extracted as the post-reaction solution, and the absorbance of the post-reaction solution is measured to obtain the post-reaction absorbance; and the absorbance loss rate is calculated according to the initial absorbance and the post-reaction absorbance, and the oxidative stability of the membrane material to be tested is determined according to the absorbance loss rate.

[0018] Optionally, the set temperature ranges from 80°C to 85°C.

[0019] Optionally, the absorbance measurement method includes ultraviolet spectrophotometry.

[0020] Optionally, the calculation formula for the absorbance loss rate is:

[0021] L=[(A0-A s ) / A0]×100%

[0022] Wherein, L is the absorbance loss rate, A0 is the initial absorbance, A s is the absorbance after the reaction.

[0023] The technical effects of a battery diaphragm testing device and testing method provided in this application are as follows: The testing device of the present invention is simple and only involves one reaction chamber, which not only avoids the impact of degradation of other components on the test results, but also avoids the problem of insufficient reaction of the battery diaphragm when it is directly immersed in the reaction solution, further reducing the error of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 This is a schematic diagram of a battery separator testing device provided in this application;

[0026] Figure 2 is a schematic diagram of the first reaction frame 121 provided in this application;

[0027] Figure 3 is a schematic diagram of the second reaction frame 122 provided in this application;

[0028] Figure 4 This is a flow chart of a battery separator testing method provided in this application. DETAILED DESCRIPTION

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0030] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0031] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0032] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0033] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0034] Reference Figure 1, is a schematic diagram of a battery separator testing device 100 proposed in this application, comprising a reaction system 10, a circulation system 20 and a temperature control system 30. The reaction system 10 comprises a housing 11, two reaction frames 12 (a first reaction frame 121 and a second reaction frame 122) and a membrane material to be tested 13, wherein the membrane material to be tested 13 is located between the two reaction frames 12, and the housing 11 is located on a side of each reaction frame 12 away from the membrane material to be tested 13. Furthermore, the circulation system 20 is used to provide a reaction solution to the reaction system 10 and to receive a reaction solution flowing out of the reaction system 10. The temperature control system 30 is used to detect the reaction temperature of the reaction solution and maintain the reaction temperature at a target temperature when the testing device 100 is working. In this embodiment, preferably, the membrane material 13 to be tested is a perfluorosulfonic acid proton exchange membrane, the shell 11 and the reaction frame 12 are both corrosion-resistant, preferably, the shell 11 and the reaction frame 12 are made of polytetrafluoroethylene, the reaction solution is a Fenton reagent, and the Fenton reagent includes 2% to 4% H2O2 and 1.2 mmol / L to 3.9 mmol / L Fe 2+ The Fenton reagent has the characteristic of rapid reaction and can react quickly with the membrane material to be tested 13, greatly reducing the reaction time and improving the test efficiency.

[0035] Figure 2 and Figure 3 Schematic diagrams of the first reaction frame 121 and the second reaction frame 122, respectively. In the present embodiment, preferably, the reaction frame 12 has a middle hollow portion 123, the middle hollow portion 123 is used to accommodate the reaction solution, and the middle hollow portions 123 of the two reaction frames 12 are connected together to form a reaction chamber, and the film material 13 to be tested reacts in the reaction chamber. The reaction frame 12 also has a frame portion 124, which is located around the middle hollow portion 123, and the side of the frame portion 124 is provided with a plurality of first holes 125. In the present embodiment, preferably, the housing 11 is provided with a plurality of second holes 111, and the plurality of first holes 125 correspond to the plurality of second holes 111, and the first holes 125 and the second holes 111 are suitable for allowing bolts to pass through to connect and fix the reaction frame 12 and the housing 11.

[0036] In this embodiment, preferably, a sealing line 14 is further included, which is arranged on the reaction frame 12. The sealing line 14 is located on the side of the reaction frame 12 that contacts the film material to be tested 13, and is located at the junction of the frame portion 124 and the middle hollow portion 123. The sealing line 14 is used to seal the film material to be tested 13 and the reaction frame 12. Specifically, the two reaction frames 12 respectively have a first sealing line 141 and a second sealing line 142. In the reaction system 10, the projections of the first sealing line 141 and the second sealing line 142 on the film material to be tested 13 do not overlap, that is, the first sealing line 141 and the second sealing line 142 are staggered. The sealing of the film material to be tested 13 and the reaction frame 12 is achieved by the sealing line 14. The staggered arrangement of the first sealing line 141 and the second sealing line 142 can further enhance the sealing effect of the film material to be tested 13.

[0037] In this embodiment, preferably, the circulation system 20 includes a peristaltic pump 21, a liquid storage tank 22, a liquid inlet pipe 23, and a liquid outlet pipe 24. The liquid storage tank 22 is used to hold the reaction solution, one end of the liquid inlet pipe 23 and the liquid outlet pipe 24 are both inserted into the liquid storage tank 22, the other end of the liquid inlet pipe 23 is inserted into the reaction system, and the other end of the liquid outlet pipe 24 is inserted into the reaction system. In this embodiment, preferably, the housing 11 also has a liquid inlet 112 and a liquid outlet 113, the other end of the liquid inlet pipe 23 is inserted into the liquid inlet 112, and the other end of the liquid outlet pipe 24 is inserted into the liquid outlet 113. The peristaltic pump 21 is provided on the liquid inlet pipe 23 and is used to circulate the reaction solution between the liquid storage tank 22 and the reaction system 10.

[0038] In the present embodiment, preferably, the circulation system 20 further comprises a defoaming device 25, the defoaming device 25 comprises a bracket 251 and an agitator 252, the top of the agitator 252 is fixed on the bracket 251, and the stirring portion 2521 of the agitator 252 is located in the liquid storage tank 22. In a specific implementation, the stirring portion 2521 can be a spiral blade. The defoaming device 25 mixes the reaction solution evenly by stirring, and at the same time can eliminate the bubbles generated by the reaction system 10 to prevent the bubbles from hindering the reaction. In the present embodiment, the liquid storage tank 22, the liquid inlet pipe 23, the liquid outlet pipe 24 and the agitator 252 are all corrosion-resistant. Preferably, the material of the liquid storage tank 22 includes borosilicate glass; and / or the materials of the liquid inlet pipe 23 and the liquid outlet pipe 24 include polypropylene respectively; and / or the material of the agitator 252 includes polytetrafluoroethylene.

[0039] In the present embodiment, preferably, the temperature control system 30 includes a constant temperature heater 31, which is used to heat the reaction solution in the liquid storage tank 22 and maintain the reaction temperature of the reaction solution at the target temperature. Preferably, the reaction temperature can be better controlled by heating in a water bath to ensure the stable reaction. The temperature control system 30 also includes a temperature sensor 32, and the top of any reaction frame 12 is also provided with a third hole 126, which is used to place the temperature sensor 32. The temperature sensing probe of the temperature sensor 32 (not shown in the figure) is suitable for entering the middle hollow portion 123 of the reaction frame 12. Preferably, the temperature sensor 32 has a protective shell, which is corrosion-resistant and is preferably made of polypropylene.

[0040] The battery diaphragm testing device 100 proposed in the present application is simple, involving only a reaction chamber composed of two reaction frames 12. The diaphragm to be tested is placed in the reaction chamber for reaction, which not only avoids the impact of degradation of other components on the test results, but also avoids the problem of insufficient reaction of the battery diaphragm when it is directly immersed in the reaction solution, further reducing the error of the test results. In addition, the use of Fenton reagent as the reaction solution greatly improves the reaction speed, reduces the reaction time, and improves the efficiency of the test.

[0041] Reference Figure 4 The present application also provides a battery separator testing method 40, which is applied to the battery separator testing device 100. The specific steps of the testing method 40 are as follows:

[0042] S401: Place the film material to be tested in the reaction system of the test device. For example, the film material to be tested 13 can be cut into a regular rectangle, and then placed between the two reaction frames 12 of the reaction system 10 and fastened.

[0043] S402, start the temperature control system of the test device to heat the reaction solution, and start the circulation system of the test device to allow the reaction solution to enter the reaction system and react with the membrane material to be tested. In this embodiment, preferably, Fenton reagent is prepared as the reaction solution, an appropriate amount of Fenton reagent is added to the liquid storage tank 22, the temperature sensor 32 is inserted into the reaction system 10, the constant temperature heater 31 and the stirrer 252 are turned on, the target temperature and reaction time of the constant temperature heater 31 are set, and the two peristaltic pumps 21 are turned on to circulate the reaction solution. Preferably, the target temperature range is 80℃~85℃, and the reaction time is greater than or equal to 3h.

[0044] S403. The reaction temperature of the reaction solution is detected by the temperature control system. When the reaction temperature reaches the set temperature, a specified amount of the reaction solution is extracted as the initial reaction solution, and the absorbance of the initial reaction solution is measured to obtain an initial absorbance. In this embodiment, preferably, when it is detected that the reaction temperature reaches the set temperature, a specified amount of the reaction solution is taken from the liquid storage tank 22 as the initial reaction solution, and then the initial absorbance A0 of the initial reaction solution is measured by ultraviolet spectrophotometry. Preferably, the ultraviolet spectrophotometry is salicylic acid spectrophotometry, using salicylic acid as a scavenger for ·OH generated by the Fenton reagent, and its reaction product has a characteristic absorption peak at a specific wavelength.

[0045] S404. When the reaction time reaches the set time, the temperature control system and the circulation system are stopped, and the reaction solution of the specified amount is extracted as the post-reaction solution, and the absorbance of the post-reaction solution is measured to obtain the post-reaction absorbance. In this embodiment, preferably, when the reaction time reaches the set time, the temperature control system and the circulation system are turned off, heating, circulation and stirring are stopped, and the reaction solution of the specified amount is extracted from the liquid storage tank 22 again as the post-reaction solution. After the post-reaction solution is cooled, the post-reaction absorbance A of the post-reaction solution is measured by ultraviolet spectrophotometry. s .

[0046] S405. Calculate the absorbance loss rate based on the initial absorbance and the absorbance after the reaction, and determine the oxidative stability of the membrane material to be tested based on the absorbance loss rate. The absorbance loss rate of the solution before and after the reaction reflects the degree of oxidation of the battery separator. The greater the absorbance loss rate before and after the reaction, the more ·OH is consumed during the reaction, the deeper the degree of oxidation of the battery separator, and the poorer its antioxidant properties. Specifically, the absorbance loss rate is calculated as follows:

[0047] L=[(A0-A s ) / A0]×100%

[0048] Wherein, L is the absorbance loss rate, A0 is the initial absorbance, A s is the absorbance after the reaction.

[0049] For ease of understanding, a specific embodiment of a testing method 40 using the above-mentioned battery separator is shown below.

[0050] Example 1

[0051] (S1) Weigh 0.0345 g of salicylic acid and dissolve it in 50 mL of ethanol to obtain a 5 mmol / L salicylic acid-ethanol solution, which is set aside. Prepare a 0.1 mol / L NaOH solution, which is set aside.

[0052] (S2) Cut a piece of about 10×8cm 2The perfluorosulfonic acid proton exchange membrane is used as the membrane material 13 to be tested, and the membrane material 13 to be tested is placed in the reaction system 10 to ensure that the reaction area is 6×5 cm 2 .

[0053] (S3) Fasten the reaction system 10 with eight bolts and connect the pipelines of each part.

[0054] (S4) Prepare 50-100 mL of Fenton's reagent: dilute a commercially available 30% H2O2 solution to obtain a 2% H2O2 solution, weigh 1.3902 g of Fe2SO4 and dissolve it in 50 mL of deionized water to obtain a 0.1 mol / LFe2SO4 solution; take an appropriate amount of the above Fe2SO4 solution and add it to 50-100 mL of H2O2 solution to obtain 2% H2O2 + 1.2 mmolFe 2+ Fenton's reagent.

[0055] (S5) The Fenton reagent is added to the liquid storage tank 22, and the two peristaltic pumps 21 are turned on to circulate the reaction solution. The temperature sensor 32 is inserted into the reaction system 10, and the constant temperature heater 31 and the stirrer 252 are turned on. The target temperature of the constant temperature heater 31 is set to 80-85° C., and the reaction time is set to be not less than 3 hours.

[0056] (S6) After the real-time temperature displayed by the constant temperature heater 31 reaches the target temperature, 3 mL of the reaction solution is taken from the liquid storage tank 22, 1 mL of the above-mentioned 5 mmol / L salicylic acid-ethanol solution is added, and the mixture is shaken and mixed evenly. After standing for 10 minutes, the above-mentioned 0.1 mol / L NaOH solution is added, and the absorbance is then measured by ultraviolet spectrophotometer, which is recorded as the initial absorbance A0 of the reaction solution.

[0057] (S7) After the set reaction time is reached, the constant temperature heater 31, the two peristaltic pumps 21 and the stirrer 252 are stopped, and 3 mL of the reacted solution is taken from the liquid storage tank 22 again. After the solution is cooled, the absorbance is measured according to the steps of (S6), and recorded as the absorbance of the reacted solution A s .

[0058] (S8) By the formula L=[(A0-A s ) / A0]×100% to calculate the loss rate of absorbance L, and calculate the average value of three parallel samples.

[0059] The test results of Example 1 are shown in Table 1 below:

[0060]

[0061] Table 1

[0062] Example 2

[0063] (S1) Weigh 0.0345 g of salicylic acid and dissolve it in 50 mL of ethanol to obtain a 5 mmol / L salicylic acid-ethanol solution, which is set aside. Prepare a 0.1 mol / L NaOH solution, which is set aside.

[0064] (S2) Cut a piece of about 10×8cm 2 The perfluorosulfonic acid proton exchange membrane is used as the membrane material 13 to be tested, and the membrane material 13 to be tested is placed in the reaction system to ensure that the reaction area is 6×5 cm 2 .

[0065] (S3) Fasten the reaction system with eight bolts and connect the various pipelines.

[0066] (S4) Prepare 50-100 mL of Fenton's reagent: dilute a commercially available 30% H2O2 solution to obtain a 3% H2O2 solution, weigh 1.3902 g of Fe2SO4 and dissolve it in 50 mL of deionized water to obtain a 0.1 mol / LFe2SO4 solution; take an appropriate amount of the above Fe2SO4 solution and add it to 50-100 mL of H2O2 solution to obtain 3% H2O2 + 2.2 mmolFe 2+ Fenton's reagent.

[0067] (S5) The Fenton reagent is added to the liquid storage tank 22, and the two peristaltic pumps 21 are turned on to circulate the reaction solution. The temperature sensor 32 is inserted into the reaction system 10, and the constant temperature heater 31 and the stirrer 252 are turned on. The target temperature of the constant temperature heater 31 is set to 80-85° C., and the reaction time is set to be not less than 3 hours.

[0068] (S6) After the real-time temperature displayed by the constant temperature heater 31 reaches the target temperature, 3 mL of the reaction solution is taken from the liquid storage tank 22, 1 mL of the above-mentioned 5 mmol / L salicylic acid-ethanol solution is added, and the mixture is shaken and mixed evenly. After standing for 10 minutes, the above-mentioned 0.1 mol / L NaOH solution is added, and the absorbance is then measured by ultraviolet spectrophotometer, which is recorded as the initial absorbance A0 of the reaction solution.

[0069] (S7) After the set reaction time is reached, the constant temperature heater 31, the two peristaltic pumps 21 and the stirrer 252 are stopped, and 3 mL of the reacted solution is taken from the liquid storage tank 22 again. After the solution is cooled, the absorbance is measured according to the steps of (S6), and recorded as the absorbance of the reacted solution A s

[0070] (S8) By the formula L=[(A0-A s ) / A0]×100% to calculate the loss rate of absorbance L, and calculate the average value of three parallel samples.

[0071] The test results of Example 2 are shown in Table 2 below:

[0072]

[0073] Table 2

[0074] Example 3

[0075] (S1) Weigh 0.0345 g of salicylic acid and dissolve it in 50 mL of ethanol to obtain a 5 mmol / L salicylic acid-ethanol solution, which is set aside. Prepare a 0.1 mol / L NaOH solution, which is set aside.

[0076] (S2) Cut a piece of about 10×8cm 2 The perfluorosulfonic acid proton exchange membrane is used as the membrane material 13 to be tested, and the membrane material 13 to be tested is placed in the reaction system to ensure that the reaction area is 6×5 cm 2 .

[0077] (S3) Fasten the reaction system with eight bolts and connect the various pipelines.

[0078] (S4) Prepare 50-100 mL of Fenton's reagent: dilute a commercially available 30% H2O2 solution to obtain a 4% H2O2 solution, weigh 1.3902 g of Fe2SO4 and dissolve it in 50 mL of deionized water to obtain a 0.1 mol / LFe2SO4 solution; take an appropriate amount of mL of the above Fe2SO4 solution and add it to 50-100 mL of H2O2 solution to obtain 4% H2O2 + 3.9 mmolFe 2+ Fenton's reagent.

[0079] (S5) The Fenton reagent is added to the liquid storage tank 22, and the two peristaltic pumps 21 are turned on to circulate the reaction solution. The temperature sensor 32 is inserted into the reaction system 10, and the constant temperature heater 31 and the stirrer 252 are turned on. The target temperature of the constant temperature heater 31 is set to 80-85° C., and the reaction time is set to be not less than 3 hours.

[0080] (S6) After the real-time temperature displayed by the constant temperature heater 31 reaches the target temperature, 3 mL of the reaction solution is taken from the liquid storage tank 22, 1 mL of the above-mentioned 5 mmol / L salicylic acid-ethanol solution is added, and the mixture is shaken and mixed evenly. After standing for 10 minutes, the above-mentioned 0.1 mol / L NaOH solution is added, and the absorbance is then measured by ultraviolet spectrophotometer, which is recorded as the initial absorbance A0 of the reaction solution.

[0081] (S7) After the set reaction time is reached, the constant temperature heater 31, the two peristaltic pumps 21 and the stirrer 252 are stopped, and 3 mL of the reacted solution is taken from the liquid storage tank 22 again. After the solution is cooled, the absorbance is measured according to the steps of (S6), and recorded as the absorbance of the reacted solution A s

[0082] (S8) By the formula L=[(A0-A s ) / A0]×100% to calculate the loss rate of absorbance L, and calculate the average value of three parallel samples.

[0083] The test results of Example 3 are shown in Table 3 below:

[0084]

[0085] Table 3

[0086] As shown in Tables 1-3 above, the same membrane material was tested three times in the examples, and the test results of the three parallel samples were very close, indicating that the method has good stability and operational repeatability.

[0087] The test method of the battery separator provided in this application is different from the conventional method of immersing the battery separator in VO2 + The testing method in electrolyte saves a lot of testing time and improves testing efficiency. It not only avoids the impact of degradation of other components on the test results, but also avoids the problem of insufficient reaction of the battery separator when it is directly immersed in the reaction solution, further reducing the error of the test results.

[0088] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely examples and do not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to the present application. Such modifications, improvements, and revisions are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0089] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0090] Similarly, it should be noted that, in order to simplify the description of this application and thus facilitate understanding of one or more embodiments of the application, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, the features of an embodiment may be fewer than all the features of the individual embodiments disclosed above.

[0091] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0092] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A battery separator testing device, characterized in that: include: A reaction system comprising a housing, two reaction frames, and a membrane material to be tested, wherein the membrane material to be tested is located between the two reaction frames, and the housing is located on a side of each reaction frame away from the membrane material to be tested, wherein the reaction frame has a middle hollow portion for accommodating a reaction solution; a circulation system for supplying the reaction solution to the reaction system and receiving the reaction solution flowing out of the reaction system; and The temperature control system is used to detect the reaction temperature of the reaction solution and maintain the reaction temperature at a target temperature when the testing device is working.

2. The testing device according to claim 1, wherein: The reaction frame also has a frame portion, which is located around the middle hollow portion. The side of the frame portion is provided with a plurality of first holes, and the outer shell is provided with a plurality of second holes. The plurality of first holes correspond to the plurality of second holes, and the first holes and the second holes are suitable for allowing bolts to pass through to connect and fix the reaction frame and the outer shell.

3. The testing device according to claim 2, wherein: It also includes a sealing line, which is arranged on the reaction frame. The sealing line is located on the side of the reaction frame that contacts the film material to be tested and is located at the junction of the frame portion and the middle hollow portion. The sealing line is used to seal the film material to be tested and the reaction frame.

4. The testing device according to claim 3, wherein: in, The two reaction frames respectively have a first sealing line and a second sealing line. In the reaction system, the projections of the first sealing line and the second sealing line on the film material to be tested do not overlap.

5. The testing device according to claim 1, wherein: The circulation system includes a peristaltic pump, a liquid storage tank, a liquid inlet pipe and a liquid outlet pipe; wherein, The liquid storage tank is used to contain the reaction solution, one end of the liquid inlet pipe and the liquid outlet pipe are both inserted into the liquid storage tank, the other end of the liquid inlet pipe is inserted into the reaction system, and the other end of the liquid outlet pipe is inserted into the reaction system; The peristaltic pump is arranged on the liquid inlet pipe, and is used to make the reaction solution circulate between the liquid storage tank and the reaction system.

6. The testing device according to claim 5, wherein: The circulation system further comprises a defoaming device, which comprises a bracket and a stirrer. The top of the stirrer is fixed on the bracket, and the stirring part of the stirrer is located in the liquid storage tank.

7. The testing device according to claim 6, wherein: The material of the liquid storage tank includes borosilicate glass; and / or The material of the liquid inlet pipe and the liquid outlet pipe respectively includes polypropylene; and / or The material of the stirrer includes polytetrafluoroethylene.

8. The testing device according to claim 5, wherein: The temperature control system includes a constant temperature heater, which is used to heat the reaction solution in the liquid storage tank and maintain the reaction temperature of the reaction solution at the target temperature.

9. The testing device according to claim 8, wherein: The temperature control system also includes a temperature sensor. A third hole is provided on the top of any of the reaction frames. The third hole is used to place the temperature sensor. The temperature sensing probe of the temperature sensor is suitable for entering the middle hollow portion of the reaction frame. The temperature sensor has a protective shell, and the material of the protective shell is polypropylene.

10. The testing device according to any one of claims 1 to 9, characterized in that: The membrane material to be tested is a perfluorosulfonic acid proton exchange membrane, and / or The shell and the reaction frame are both made of polytetrafluoroethylene.

11. The testing device according to any one of claims 1 to 9, characterized in that: The reaction solution is a Fenton reagent, which includes 2% to 4% H2O2 and 1.2 mmol / L to 3.9 mmol / L Fe 2+ .

12. A method for testing a battery separator, characterized in that: Applied to the testing device according to any one of claims 1 to 11, the testing method comprises: Placing the membrane material to be tested in the reaction system of the testing device; Starting the temperature control system of the test device to heat the reaction solution, and starting the circulation system of the test device to allow the reaction solution to enter the reaction system and react with the membrane material to be tested; detecting the reaction temperature of the reaction solution by a temperature control system, extracting a specified amount of the reaction solution as an initial reaction solution when the reaction temperature reaches a set temperature, and measuring the absorbance of the initial reaction solution to obtain an initial absorbance; When the reaction time reaches a set time, stopping the temperature control system and the circulation system, extracting a specified amount of the reaction solution as a post-reaction solution, and measuring the absorbance of the post-reaction solution to obtain a post-reaction absorbance; and The absorbance loss rate is calculated according to the initial absorbance and the absorbance after the reaction, and the oxidation stability of the film material to be tested is determined according to the absorbance loss rate.

13. The testing method according to claim 12, wherein: The set temperature range is 80°C to 85°C.

14. The testing method according to claim 12, wherein: The absorbance determination method includes ultraviolet spectrophotometry.

15. The testing method according to claim 12, wherein: The calculation formula of the absorbance loss rate is: L=[(A0-A s ) / A0]×100% Wherein, L is the absorbance loss rate, A0 is the initial absorbance, A s is the absorbance after the reaction.

Images