Method and device for detecting wettability of electrolyte

Abstract

The present invention relates to the technical field of lithium-ion power batteries, and provides a method and device for detecting the wettability of an electrolyte. The method comprises: adding deionized water and a water-removing additive to an initial electrolyte to obtain an electrolyte for detection; soaking a battery cell in the electrolyte for detection for a preset time; wherein the battery cell comprises a plurality of closely stacked electrode sheets; taking out the soaked battery cell, splitting the soaked battery cell, and obtaining a plurality of electrode sheets; dividing a plurality of areas to be tested at a preset position on the surface of each electrode sheet; obtaining the water distribution in each area to be tested, and determining the wettability of the electrolyte for detection according to the water distribution. Through the method for detecting the wettability of the electrolyte of the present invention, water can be used as a calibration material for detecting the wettability of the electrolyte, so as to more simply and quickly realize the detection of the wettability of the electrolyte, and provide effective data and theoretical support for the further development of subsequent lithium-ion power batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion power batteries, and in particular to a method for detecting wettability of an electrolyte and a device for detecting wettability of an electrolyte. Background Art

[0002] As a key component of lithium-ion power batteries, electrolyte affects whether the battery can be charged and discharged normally. Among them, the wettability of electrolyte to the battery cell is directly related to the transmission efficiency of ions inside the battery. Good wettability indicates that the electrolyte fully penetrates into the pores of the electrode material, thereby ensuring the efficient transmission of lithium ions, which in turn affects the performance of the battery.

[0003] In the related art, the method for detecting the wettability of battery cell electrolyte is mostly through the contact measurement angle method. However, the operational complexity and high testing cost of this detection method are not conducive to its widespread application in production and manufacturing. Alternatively, a calibration reagent containing an organic luminescent material or a fluorescent material is added to the electrolyte during the detection, and the wettability of the electrolyte is judged by detecting the distribution of the organic luminescent material or the fluorescent material. However, this detection method is relatively subjective and cannot quantify the wettability results, which affects the accuracy of the detection. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to provide a method for detecting the wettability of an electrolyte, which can use water as a calibration material for detecting the wettability of an electrolyte, and can detect the wettability of an electrolyte more simply and accurately.

[0005] The second objective of the present invention is to provide a device for detecting the wettability of an electrolyte.

[0006] To achieve the above-mentioned purpose, the first embodiment of the present invention proposes a method for detecting the wettability of an electrolyte, comprising: adding deionized water and a dehydrating additive to an initial electrolyte to obtain an electrolyte for detection; soaking a battery cell in the electrolyte for a preset time; wherein the battery cell comprises a plurality of closely stacked electrode sheets; taking out the soaked battery cell, splitting the soaked battery cell, and obtaining a plurality of electrode sheets; dividing a plurality of test areas at a preset position on the surface of each electrode sheet; obtaining the water distribution in each test area, and determining the wettability of the electrolyte for detection according to the water distribution. The present application adds a trace amount of a dehydrating additive to the electrolyte to complex water molecules, thereby avoiding the hydrolysis of lithium salts in the electrolyte, solving the problem that water cannot be used as a calibration material for detecting the wettability of the electrolyte, and further quantitatively analyzing the wettability of the electrolyte by detecting the water value of the sample, thereby improving the accuracy of evaluating the wettability of the electrolyte, making the wettability detection of the electrolyte more convenient, and improving the detection efficiency.

[0007] In addition, the method for detecting wettability of electrolyte according to the above embodiment of the present invention may also have the following additional technical features:

[0008] According to some embodiments of the present invention, the water content of the initial electrolyte is 0-10 ppm.

[0009] According to some embodiments of the present invention, the concentration of deionized water added to the initial electrolyte is in the range of 500 ppm to 5000 ppm.

[0010] According to some embodiments of the present invention, the concentration of the water-removing additive added to the initial electrolyte is in the range of 0.5% to 5%.

[0011] According to some embodiments of the present invention, the water removal additive is a silane additive, including tris(trimethylsilyl)borate and / or tris(trimethylsilyl)phosphite.

[0012] According to some embodiments of the present invention, the ambient temperature of the soaked battery cell is 30-60°C.

[0013] According to some embodiments of the present invention, the preset time for soaking the battery cell is 12 to 48 hours.

[0014] According to some embodiments of the present invention, obtaining the moisture distribution in each area to be tested, and determining the wettability of the detection electrolyte according to the moisture distribution, includes:

[0015] The wettability of the electrolyte is determined by taking samples from different test areas on each electrode sheet of the battery cell and detecting the moisture distribution in each sample.

[0016] According to some embodiments of the present invention, samples are taken from at least three different areas to be tested on the electrode sheet.

[0017] To achieve the above-mentioned purpose, the second embodiment of the present invention proposes a device for detecting the wettability of an electrolyte, which is used to execute the above-mentioned method for detecting the wettability of an electrolyte. The device for detecting the wettability of an electrolyte provided by the present invention complexes water molecules by adding a trace amount of water-removing additive into the electrolyte, thereby avoiding the hydrolysis of lithium salts in the electrolyte, solving the problem that water cannot be used as a calibration material for detecting the wettability of the electrolyte, and further quantitatively analyzing the wettability of the electrolyte by detecting the moisture value of the sample. While improving the accuracy of evaluating the wettability of the electrolyte, the wettability detection of the electrolyte is made simpler and more convenient, thereby improving the detection efficiency.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A flow chart of a method for detecting wettability of an electrolyte provided in an embodiment of the present invention.

[0021] Figure 2 A schematic diagram of a battery cell structure provided in an embodiment of the present invention.

[0022] Figure 3 Schematic diagram of a device for detecting wettability of electrolyte provided in an embodiment of the present invention.

[0023] Reference numerals:

[0024] 300-Detection device. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0026] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] As described in the background technology section, the electrolyte transfers ions between the positive and negative electrodes of the battery to achieve battery charging and discharging. The wettability of the electrolyte has a great influence on the working efficiency of lithium-ion power batteries. When the electrolyte can fully penetrate into the electrode material, the ion transmission efficiency is high. At this time, the energy density of the battery is high, and its service life and charging speed will also increase accordingly. Therefore, the detection of electrolyte wettability is an indispensable part of the quality inspection of lithium-ion power batteries.

[0028] In the process of realizing the present invention, the applicant discovered that in the related art, the wettability of the electrolyte can be detected by judging the contact angle of the electrode sheet. However, due to the fast spreading speed of the electrolyte, a high-speed camera is required, the detection cost is high and the detection effect may be biased. The wettability of the electrolyte can also be detected by adding fluorescent or luminescent materials and judging the wettability of the electrolyte based on the content of the fluorescent or luminescent materials. However, this detection method is cumbersome and costly, which is not conducive to application in large-scale production environments.

[0029] To this end, the present invention provides an electrolyte wettability detection method, which can accurately determine the electrolyte wettability while simplifying the detection operation and reducing the detection cost.

[0030] The technical solution of the present invention is further described in detail below through specific embodiments.

[0031] refer to Figure 1 , a flow chart of a method for detecting electrolyte wettability provided in an embodiment of the present invention.

[0032] Step S101, adding deionized water and a water-removing additive to an initial electrolyte to obtain an electrolyte for detection.

[0033] Specifically, the initial electrolyte is usually a standard electrolyte pre-configured according to the design requirements of the lithium-ion power battery, and is usually prepared from raw materials such as high-purity organic solvents, electrolyte lithium salts, and necessary additives under certain conditions and in a certain proportion. The initial electrolyte generally has high conductivity and high stability and is a carrier for ion transmission in lithium-ion power batteries. In order to manufacture the electrolyte detection environment of the present invention, it is necessary to further add deionized water and water-removing additives to the initial electrolyte to further obtain an electrolyte for detection.

[0034] As an optional embodiment, the water content of the initial electrolyte is 0-10 ppm.

[0035] Specifically, the moisture content of the electrolyte is related to the performance and safety of the lithium battery. Since water will react with the lithium ions in the electrolyte, it will cause corrosion inside the battery, further affecting the cycle life and performance of the battery. Therefore, the moisture content of the initial electrolyte needs to be controlled at 0-10ppm to ensure the performance and safety of the battery and extend the service life of the battery.

[0036] It should be noted that ppm (Parts Per Million) is a unit of solute concentration, meaning "parts per million", indicating the mass of the solute accounts for one millionth of the mass of the total solution, also known as parts per million concentration. Specifically, 1 ppm means that there is 1 part of solute in 1,000,000 parts of solution, that is, the mass of the solute accounts for one millionth of the total mass of the solution. PPM is similar to percentage (%), but the ratio of ppm is larger than that of percentage, and the conversion relationship is 1% = 10,000 ppm.

[0037] Deionized water is a high-purity water obtained by removing ions and impurities from water. Since the initial electrolyte is a non-aqueous electrolyte, the water content is usually less than 10ppm. Adding a small amount of deionized water to the initial electrolyte can make it possible to more accurately detect the moisture content at each position of the electrode sheet and improve the accuracy of judging the wettability of the electrolyte.

[0038] As an optional embodiment, the concentration range of deionized water added to the initial electrolyte is 500ppm to 5000ppm.

[0039] Specifically, the concentration range of deionized water added to the initial electrolyte is maintained at 500ppm to 5000ppm, which can ensure that the electrode sheet can be completely wetted to achieve the detection of the wettability of the electrolyte.

[0040] The dehydrating additive can complex water molecules, and the dehydrating additive molecules usually contain functional groups that can form hydrogen bonds (a weak interaction force between molecules) with water molecules. When adding deionized water to the initial electrolyte, the dehydrating additive is added. At this time, the dehydrating additive can form a stable complex with the water molecules, that is, the water molecules are "fixed" in the complex, and the activity is greatly reduced. Therefore, the hydrolysis reaction of the lithium salt can be effectively inhibited, and water can be used as a calibration reagent. Furthermore, when it is necessary to detect the moisture content inside the electrode sheet, the hydrogen bonds in the electrolyte can be destroyed by a specific method to release the complexed water molecules, and the wettability of the electrolyte can be further detected.

[0041] As an optional embodiment, the concentration of the water-removing additive added to the initial electrolyte is in the range of 0.5% to 5%.

[0042] Specifically, the concentration range of the dehydrating additive is 0.5% to 5% of the total mass of the initial electrolyte, and the concentration of the dehydrating additive needs to correspond to the concentration of the added deionized water, so that the dehydrating additive can complex with water molecules, so that the added deionized water does not react with the lithium salt in the electrolyte, thereby inhibiting the hydrolysis of the lithium salt.

[0043] As an optional embodiment, the water removal additive is a siloxane, a silazane, a phosphite and a nitrogen-containing compound, including one or more of tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphite, trimethylsilyl imidazole, trimethylsilyl oxazolidinone, dimethyldiphenoxysilane, N-acetylcaprolactam, and cyclopentyl isocyanate.

[0044] Specifically, the water-removing additive may be a silane additive. The preferred silane water-removing additive in the embodiment of the present invention includes tris(trimethylsilyl)borate, the chemical formula of which is C9H 27 BO3Si3, referred to as TMSB, also includes (trimethylsilyl) phosphite, with the chemical formula C3H 10 O3PSi, referred to as TMSP. TMSP and TMSB, as water removal additives, can better complex with water molecules, ensuring that the electrolyte is in a stable state before the wettability of the electrolyte is tested, thereby improving the accuracy of the test.

[0045] Step S102, immersing the battery cell in a detection electrolyte for a preset time; wherein the battery cell includes a plurality of closely stacked electrode sheets.

[0046] Specifically, the battery cell is formed by closely stacking and assembling a number of dry electrode sheets. Further, the detection electrolyte is injected into the dry battery cell, and the dry battery cell is left to stand for a preset time. In an embodiment of the present invention, the preset time for immersion is preferably 12 to 48 hours, and the specific value of the preset time can also be set according to actual conditions.

[0047] As an optional embodiment, the ambient temperature of the soaked battery cell is 30-60°C.

[0048] Specifically, since deionized water and water-removing additives are added to the detection electrolyte, a stable hydrogen bond network exists in the detection electrolyte at this time. It is necessary to break the hydrogen bonds at a temperature of 30 to 60°C to release the complexed water molecules so that the water molecules exist in the form of free water. This is the basic condition for the subsequent detection of the wettability of the electrolyte.

[0049] As an optional embodiment, the preset time for soaking the battery cell is 12 to 48 hours.

[0050] Specifically, in order to allow the battery cell electrode sheets to fully absorb the detection electrolyte, the preset time for soaking the battery cell is 12 to 48 hours. If the soaking time is too short, it may affect the soaking effect of the battery cell and thus affect the accuracy of the inspection; if the soaking time is too long, it may cause unnecessary damage to the battery cell, which also affects the accuracy of the inspection.

[0051] Step S103, taking out the soaked battery cell, and splitting the soaked battery cell to obtain a plurality of electrode sheets.

[0052] refer to Figure 2 , a diagram of a battery cell structure provided by an embodiment of the present invention.

[0053] Specifically, after the soaking is completed, the soaked battery cell is taken out and the soaked battery cell is split to further obtain a plurality of soaked electrode sheets. A1 represents the first electrode sheet, A M It represents the Mth electrode sheet, i.e. the middlemost layer.

[0054] Step S104, dividing a plurality of test areas at preset positions on the surface of each electrode sheet.

[0055] Specifically, the shapes and areas of the several test areas divided at the preset positions on the surface of each electrode sheet can be the same or different. The mass range of the test area provided in the embodiment of the present invention is preferably 0.1 to 3g. Through the divided several test areas, the wettability of the electrode sheet electrolyte can be more accurately and comprehensively detected, thereby improving the accuracy of the detection.

[0056] As an optional embodiment, samples are taken from at least three different areas to be tested on the electrode sheet.

[0057] Specifically, it is necessary to select at least three different test areas on the electrode sheet for sampling, and the sampling area can be an edge area or a middle area. Figure 2 As shown, A 11 Indicates the edge position of the first electrode sheet, A 1N Indicates the middle position of the first electrode sheet, and the accuracy of the detection is ensured by sampling multiple different areas.

[0058] Step S105, obtaining the water distribution in each area to be tested, and determining the wettability of the detection electrolyte according to the water distribution.

[0059] Specifically, instruments including but not limited to Karl Fischer moisture testers can be used to detect the moisture distribution in the test area. The working principle of the Karl Fischer moisture tester is based on the quantitative reaction of iodine and sulfur dioxide with water in the presence of an organic base (such as pyridine, methanol, etc.). When the moisture meter heating furnace heats the test area for a certain period of time, the water molecules in the test area will react with the iodine and sulfur dioxide in the reagent to generate pyridine iodide and pyridine bisulfite. Since this reaction is quantitative, that is, 1 mole of water molecules will consume 1 mole of iodine, by measuring the amount of iodine consumed, the moisture content in the test area can be indirectly determined. Further, the wettability of the detection electrolyte is analyzed according to the moisture content of different test areas. In addition, the accuracy of the Karl Fischer moisture tester is usually high, and it can accurately measure the trace moisture in the sample. When the measured moisture value deviation is within 0-5%, it proves that the electrolyte infiltration effect is good.

[0060] As an optional embodiment, the moisture distribution in each test area is obtained, and the wettability of the detection electrolyte is determined based on the moisture distribution, including: sampling at different test areas on each layer of electrode sheets of the battery cell, and detecting the moisture distribution in each sample to determine the wettability of the electrolyte.

[0061] Specifically, since the battery cell is composed of multiple layers of electrode sheets, different test areas on each layer of electrode sheets are infiltrated with different test electrolytes. Sampling different test areas on each layer of electrode sheets can more completely detect and analyze the moisture distribution in each sample, thereby ensuring the accuracy and completeness of the test data.

[0062] Refer to Table 1, which is a reference table for the detection test of electrolyte wettability provided in an embodiment of the present invention.

[0063]

[0064] Table 1

[0065] As an optional embodiment, a method for detecting the wettability of an electrolyte provided by the present invention can be detected using a Karl Fischer moisture tester, and the specific test is as follows:

[0066] Test 1:

[0067] Step S1, preparing an electrolyte for detection.

[0068] Specifically, the moisture content of the test electrolyte is within 10 ppm as the initial electrolyte, and the density of the electrolyte is 1.25 g / cm 3 , take 10g of the initial electrolyte into a centrifuge tube, further, inject 8μL of deionized water into the centrifuge tube, and add 0.1g of the water removal additive TMSP into the centrifuge tube to obtain an electrolyte for detection. At this time, the total water content in the electrolyte is 1000ppm.

[0069] Step S2, soaking the dry battery cell.

[0070] Specifically, the positive electrode sheet, the separator, and the negative electrode sheet are stacked into a dry cell, and the moisture value of the cell is baked below 100 ppm, wherein the number of positive electrode sheets is 29 layers, and the number of negative electrode sheets is 30 layers, and the dry cell is obtained after hot pressing, welding, and packaging. The assembled dry cell is injected with the detection electrolyte and soaked in an environment of 45°C for 24 hours.

[0071] Step S3, disassembling the dry battery cells.

[0072] Specifically, the soaked battery cell is taken out from the battery casing, and the battery cell is separated into separate electrode sheet layers.

[0073] Step S4, preparing samples to be tested.

[0074] Specifically, the middle position of the first electrode sheet is marked as A. 1N , the middle position of the 8th electrode sheet is marked as A 8N , the three positions of the 15th electrode sheet are marked as A 15-1 , A 15-2 , A 15-3 , 5 locations in total, use a sampler to sample the mass of each area to be tested is 200mg.

[0075] Step S5, detecting the wettability of the electrolyte.

[0076] Specifically, a Karl Fischer moisture tester was used to measure the sample to be tested, the temperature of the moisture meter heating furnace was set to 200° C., the setting time was 10 min, and the moisture content at the test endpoint was recorded.

[0077] Step S6, changing the test data and conducting a comparative experiment.

[0078] Specifically, in Experiment 2, the volume of deionized water was changed to 80 μL, and the other experimental conditions remained the same;

[0079] Specifically, in Experiment 3, the volume of deionized water was changed to 2 μL, and the other experimental conditions remained the same;

[0080] Specifically, in Experiment 4, the mass of the water removal additive was changed to 0.5 g, and the other experimental conditions remained the same;

[0081] Specifically, in experiment 5, the immersion time was changed to 12 h, and the other experimental conditions remained the same;

[0082] Specifically, in Experiment 6, the immersion time was changed to 48 h, and the other experimental conditions remained the same;

[0083] Specifically, in Experiment 7, the mass of the sampled area to be tested was changed to 2 g, and the other experimental conditions remained the same;

[0084] Specifically, in Experiment 8, the heating furnace temperature was changed to 150°C, and the other experimental conditions remained the same;

[0085] Specifically, in Experiment 9, the moisture test time was changed to 3 min, and the other experimental conditions remained the same;

[0086] Specifically, in comparative experiment 10, deionized water was not added to the initial electrolyte, and the other experimental conditions remained the same;

[0087] Specifically, in comparative experiment 11, no water-removing additive was added to the initial electrolyte, and the other experimental conditions remained the same.

[0088] According to Test 1, the score deviation of each tested area is within 0-5%, which means that the battery cell has been completely wetted.

[0089] According to Test 2, when the deionized water content in Test 2 is higher than that in Test 1, the moisture score obtained is larger, and the reagent consumption of the moisture meter is larger. At this time, the score deviation of each tested area is within 0-5%, which can be judged that the battery cell has been completely wetted.

[0090] According to Experiment 3, the deionized water content added in Experiment 3 is lower than that in Experiment 1, and the moisture content of the electrode sheet itself has a greater impact on the moisture content of the electrode sheet after infiltration. At this time, the score deviation of each tested area is outside 0-5%, and the battery cell is not completely infiltrated.

[0091] According to Test 4, more water-removing additives were added in Test 4 than in Test 1, which affected the infiltration of the electrolyte and the tested moisture content was too low. At this time, the score deviation of each tested area was outside 0-5%, and the battery cell was not completely infiltrated.

[0092] According to Test 5, the soaking time of Test 5 is shorter than that of Test 1. At this time, the score deviation of each tested area is outside 0-5%, and the cell soaking is incomplete.

[0093] According to Test 6, the soaking time of Test 6 is longer than that of Test 1, which usually affects the production efficiency. At this time, the score deviation of each tested area is within 0-5%, which can be judged that the battery cell is completely soaked.

[0094] According to Test 7, the sampling quality of Test 7 is larger than that of Test 1, the moisture of the electrode sheet is not completely dried out, and it is impossible to determine whether the battery cell is completely soaked.

[0095] According to Test 8, the heating furnace temperature in Test 8 was lower than that in Test 1, and the moisture was not completely dried out, so it was impossible to determine whether the battery cell was completely soaked.

[0096] According to Test 9, the heating test time of Test 9 is shorter than that of Test 1, the moisture is not completely dried out, and it is impossible to determine whether the battery cell is completely soaked.

[0097] According to comparative test 10, compared with test 1, when deionized water is not added to the standard electrolyte, the moisture content at various locations of the electrode sheets in the battery cell is low and inconsistent, and it is impossible to determine whether the battery cell is completely wetted.

[0098] According to comparative test 11, compared with test 1, when no water removal additive is added to the electrolyte, the lithium salt in the electrolyte is hydrolyzed to generate acid and some insoluble matter, which affects the wetting effect of the electrolyte.

[0099] From the above, it can be seen that the present invention provides a method for detecting the wettability of electrolyte, which overcomes the phenomenon of lithium salt hydrolysis that occurs when water is used as a calibration reagent. By injecting a trace amount of water into the electrolyte, and further using a moisture meter to accurately measure the moisture in each electrode sheet, the wettability of the electrolyte is intuitively and quantitatively characterized, which improves the accuracy of judging the wettability of the electrolyte, simplifies the detection operation, and reduces the production test cost.

[0100] It should be noted that some embodiments of the present invention are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0101] Based on the same inventive concept, corresponding to the method provided in any of the above embodiments, the present invention also provides an electrolyte wettability detection device 300, which is used to execute the above electrolyte wettability detection method and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0102] In addition, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flow chart can be performed in a different order. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0103] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0104] Although the spirit and principle of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the disclosed specific embodiments, and the division of various aspects does not mean that the features in these aspects cannot be combined to benefit, and this division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the attached claims. The scope of the attached claims conforms to the broadest interpretation, thereby including all such modifications and equivalent structures and functions.

Claims

1. A method for detecting wettability of an electrolyte, characterized in that: include: Adding deionized water and a water-removing additive to the initial electrolyte to obtain an electrolyte for detection; Immersing the battery cell in the detection electrolyte for a preset time; wherein the battery cell comprises a plurality of closely stacked electrode sheets; Taking out the soaked battery cell, and splitting the soaked battery cell to obtain the plurality of electrode sheets; Dividing a plurality of test areas at preset positions on the surface of each electrode sheet; The moisture distribution in each of the test areas is obtained, and the wettability of the detection electrolyte is determined according to the moisture distribution.

2. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The water content of the initial electrolyte is 0-10 ppm.

3. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The concentration range of the deionized water added to the initial electrolyte is 500ppm to 5000ppm.

4. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The concentration range of the water removal additive added to the initial electrolyte is 0.5% to 5%.

5. The method for detecting wettability of electrolyte according to claim 4, characterized in that: The water removal additive is siloxane, silazane, phosphite and nitrogen-containing compound, including one or more of tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphite, trimethylsilyl imidazole, trimethylsilyl oxazolidinone, dimethyldiphenoxysilane, N-acetylcaprolactam and cyclopentyl isocyanate.

6. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The ambient temperature of the battery core is 30-60°C.

7. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The preset time for soaking the battery cell is 12 to 48 hours.

8. The method for detecting wettability of electrolyte according to claim 1, characterized in that: The obtaining of the water distribution in each of the regions to be tested and determining the wettability of the detection electrolyte according to the water distribution comprises: The wettability of the electrolyte is determined by taking samples from different test areas on each layer of the electrode sheet of the battery cell and detecting the water distribution in each sample.

9. The method for detecting wettability of electrolyte according to claim 6, characterized in that: Samples are taken from at least three different areas to be tested on the electrode sheet.

10. A device for detecting wettability of electrolyte, characterized in that: The detection device performs the electrolyte wettability detection method according to any one of claims 1 to 9.

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