Device for testing electrolyte infiltration capacity of pole piece
The described device addresses the inefficiencies of existing electrode wettability tests by using a device with a partition and scale to measure electrolyte climbing on electrodes, achieving accurate and efficient wettability assessment for multiple samples.
Patent Information
- Application Number
- CN202420533968.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-19
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-03-19
AI Technical Summary
Existing methods for testing the wettability of electrodes to electrolytes are costly, require high-speed cameras, are time-consuming, and do not accurately reflect the true wettability due to fixture interference, limiting efficiency and consistency in testing multiple samples.
A device comprising a transparent container with a partition and scale for measuring the climbing height and speed of electrolyte on an electrode, utilizing capillary force without external instruments, allowing simultaneous testing of multiple samples.
The device provides accurate, efficient, and cost-effective characterization of electrode wettability through climbing height and speed, reducing test time and system errors, and facilitating rational battery design.
Smart Images
Figure CN222144796U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of pole piece testing, in particular to a device for testing the wettability of a pole piece to an electrolyte. Background Art
[0002] The electrolyte is an ionic conductor that conducts between the positive and negative electrodes of the battery. It is responsible for the transmission of ions during the charge and discharge process. The wetting effect of the electrolyte on the electrode has a great influence on the battery's capacity, internal resistance, charge and discharge performance, cycle life and temperature range. Different positive and negative electrode formulations, electrode compaction density, rolling process and diaphragm all have an impact on the wettability of the electrolyte; in addition, the electrolyte's own formulation will also affect its wetting ability. Generally, the electrode is observed to be wetted by the electrolyte by disassembling the battery cell after injection. This method can most realistically reflect the wettability of the electrode. However, for battery cell design and electrolyte selection, if some simpler test methods are used in the early stage to test the electrode's wettability to the electrolyte, there will be reasonable data reference when formulating battery cell and electrolyte plans, which can greatly reduce the experimental cost and improve efficiency.
[0003] At present, the commonly used test methods for testing the wettability of the electrode to the battery are usually to test the liquid absorption amount, liquid absorption area, liquid absorption height of the electrode or the contact angle of the electrolyte to the electrode.
[0004] CN114062201A discloses using a syringe to drop electrolyte onto the surface of an electrode on a sample table, and photographing the electrolyte dripping process, capturing an image when the electrolyte completely contacts the electrode but has not yet begun to spread, thereby obtaining the contact angle at that moment, and characterizing the wettability of the electrolyte to the electrode by the contact angle. However, due to the rapid penetration of the electrolyte on the electrode, a high-speed camera is required to capture accurate test results. This method has high testing costs and is difficult to implement.
[0005] CN113188957 discloses using a fixture to clamp and fix the electrode to be tested, inserting one end of the electrode into the electrolyte, and calculating the electrolyte wetting rate by recording the wetting area in real time. The problem with this method is that in addition to the electrolyte wetting the electrode through capillary force, a part of the electrolyte will also infiltrate into the electrode along the fixture, which cannot truly reflect the wettability of the electrode and cannot eliminate the influence of the fixture on the wetting.
[0006] CN114252363A discloses calculating and characterizing the electrode's wettability to electrolyte by testing the time and amount of liquid absorbed when the electrode sample reaches saturation. Although this method is relatively accurate, it takes a long time for the electrode to reach saturation, and there are large differences between different samples, so it takes a lot of time.
[0007] The above technologies can test the electrode's ability to wet the electrolyte to a certain extent, but the test accuracy and simplicity of the method are often not achieved at the same time. In addition, the efficiency is low. The above methods can only test one electrode sample at a time. In the actual test process, there are usually multiple samples that need to be compared and tested, and the consistency of the test conditions cannot be fully guaranteed. Therefore, it is necessary to further design a test device with accurate test results, simple methods and high test efficiency. Utility Model Content
[0008] The purpose of the utility model is to overcome the defects in the prior art and provide a device for testing the wettability of an electrode piece to an electrolyte.
[0009] A device for testing the wettability of an electrode to an electrolyte comprises a transparent container with an opening on the top surface for containing electrolyte, a partition with scale arranged in the transparent container, and an electrode hanging plate, wherein the scale on the partition is arranged without interruption from left to right and is used to read the climbing height of the electrolyte on the electrode; the partition divides the interior of the transparent container into two separated and non-communicating spaces, and the electrode hanging plate is used to hang the electrode to be tested and then place it on the upper end of the partition.
[0010] The electrode hanging plate is horizontally arranged on the open top surface of the transparent container and is perpendicular to the partition; the electrode hanging plate is in a T-shape after being connected to the partition.
[0011] Wherein, the length of the electrode hanging plate is greater than the length of the transparent container.
[0012] Wherein, the electrode to be tested is bonded and connected to the electrode hanging plate, and the electrode to be tested is perpendicular to the electrode hanging plate.
[0013] Wherein, the electrode to be tested and the electrode hanging plate are bonded and connected by a flexible adhesive tape.
[0014] Wherein, the transparent container is a rectangular cube container with an open top surface.
[0015] Wherein, the depth of the transparent container is 10-15 cm.
[0016] Wherein, the partition is fixed at a position of 1 / 2-1 / 4 of the width of the transparent container.
[0017] Wherein, the distance between adjacent scales is 1 mm.
[0018] Wherein, the top of the partition is flush with the top of the transparent container.
[0019] The test device of the utility model is simple, and utilizes the capillary force between the electrode and the electrolyte to characterize the electrode's wettability to the electrolyte through the climbing height and climbing speed of the electrolyte on the electrode. The test efficiency is high, and test results of multiple schemes can be obtained in a short time, and no external testing instrument is required. The cost is low and it is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a three-dimensional structural diagram of a device for testing the wettability of an electrode to an electrolyte according to an embodiment of the utility model.
[0021] Figure 2 This is a three-dimensional diagram of the transparent container and the partition after being assembled in the device for testing the wettability of the electrode to the electrolyte according to the embodiment of the utility model.
[0022] Figure 3 It is a side view of a device for testing the wettability of an electrode to an electrolyte according to an embodiment of the utility model.
[0023] Figure 4 This is a three-dimensional diagram of a pole piece hanging plate of a device for testing the wettability of a pole piece to an electrolyte according to an embodiment of the utility model after being bonded to a pole piece to be tested.
[0024] Figure 5 This is a graph showing the relationship between the electrolyte climbing height and time obtained when the electrode is tested by the device for testing the electrode wettability of the electrode according to an embodiment of the utility model.
[0025] Figure 6 This is a relationship diagram between the electrolyte climbing speed and time obtained when the electrode is tested by the device for testing the electrode's electrolyte wettability according to an embodiment of the utility model.
[0026] Description of reference numerals:
[0027] 1 is a transparent container, 2 is a partition with scales, 3 is a fixing plate for fixing the electrode, 4 is a flexible tape for fixing the electrode, and 5 is the electrode to be tested. DETAILED DESCRIPTION
[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0029] like Figure 1As shown, the device for testing the wettability of an electrode to an electrolyte in an embodiment of the utility model comprises a transparent container with an opening on the top surface for containing an electrolyte, a partition with scales arranged in the transparent container, and a electrode hanging plate. The scales on the partition are arranged without interruption from left to right and are used to read the climbing height of the electrolyte on the electrode. The partition divides the interior of the transparent container into two separated and non-communicating spaces, and the electrode hanging plate is used to hang the electrode to be tested and then place it on the upper end of the partition.
[0030] In the present application, the transparent container is suitable for containing electrolyte, and the container has a certain size. Preferably, a cubic container is used, and the length, width and height ratio of the transparent container is (3.5-4.5)(1.5-2.5):(1.5-2.5); the transparent container has a certain depth, and preferably the depth of the transparent container is 10-15cm; in the above-mentioned depth and length, width and height ratio, the size of the container can be designed according to your own choice. It should be noted that in the present application, the design of the length, width and height ratio of the container is for the rational use of space, and can also be improved according to actual conditions. The graduated partition is used to read the climbing height of the electrolyte on the electrode. In order to reduce the error caused by the time sequence of reading the data, it can be directly observed by human eyes, or recorded by taking pictures.
[0031] The scale on the graduated partition in the transparent container is uninterrupted from left to right, so as to facilitate observation of the climbing state of the electrolyte. More preferably, the minimum accuracy of the scale is 1 mm; the graduated partition is used to separate the container to ensure that the two sides of the container are not connected, and it is located at about 1 / 2-1 / 4 of the width of the container. Preferably, the height of the graduated partition is flush with the top of the container.
[0032] It should be noted that the transparent container and the partition with scale are made of the same material, including but not limited to polycarbonate (PC), polyimide (PI), polyvinyl pyrrolidone (PVP), polytetrafluoroethylene (PTFE), polyether ketone (PEEK) and polystyrene (PS); the transparent container and the partition have a certain thickness, preferably, the thickness range of the transparent container and the partition is 5-8mm.
[0033] In the present application, the pole piece hanging plate is placed above the partition, and is not fixed to the container. The pole piece hanging plate is a pole piece hanging plate, which is longer than the transparent container and is conveniently placed on the transparent container.
[0034] In one embodiment, the electrode to be tested is bonded to the electrode plate, and the electrode to be tested is perpendicular to the electrode plate. As a more preferred solution, the electrode to be tested is bonded to the electrode plate using a flexible tape, and the flexible tape is used to fix the electrode to be tested to the electrode plate. When bonding, a section of the flexible tape can be first fixed to a section of the electrode to be tested, with a bonding length of 10-20mm, and the other end of the flexible tape is fixed to the electrode plate to ensure that the electrode is perpendicular to the electrode plate. Figure 4 As shown, there is no limit on the width of the electrode sample to be tested, and the length is determined by the depth of the transparent container groove. The electrode to be tested is a rectangular strip.
[0035] In the present application, the composition of the electrode active material of the electrode piece to be tested is not specifically limited. The electrode piece to be tested can be a positive electrode, and the positive electrode active material can be lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, nickel cobalt manganese oxide / lithium aluminum oxide, etc.; the electrode piece to be tested can also be a negative electrode, and the negative electrode active material can be natural graphite, artificial graphite, soft / hard carbon, lithium titanate LTO, silicon-based materials SiC, SiOx, etc.
[0036] The device of the present application is used to perform a pole piece test, and the test method thereof comprises the following steps:
[0037] The first step is to dry the electrode to be tested after hot pressing in a vacuum environment, such as 80-120°C in a vacuum environment for 8-32 hours. The drying temperature and time are determined according to the electrode plan and moisture content.
[0038] The second step is to cut the electrode to be tested into samples of a certain width, such as 25mm. The length is determined by the depth of the transparent container. If the length of the electrode is 2-8mm less than the depth of the transparent container, the electrode needs to be smaller than the depth of the container, and the cut electrode sample is fixed on the electrode hanging plate with a flexible tape;
[0039] The third step is to inject a proper amount of electrolyte into the transparent container, and place the electrode plate for fixing the electrode above the container so that the lower end of the electrode is immersed in the electrolyte and the electrode is at a certain distance in front of the partition. It should be noted that the depth of the lower end of the electrode is controlled by the amount of electrolyte added.
[0040] The fourth step is to regularly record the height of the electrode wetted by the electrolyte, and then calculate the climbing height and climbing speed of the electrolyte on the electrode at different times: through the capillary force between the electrolyte and the electrode, the electrolyte will climb upward along the electrode, and the climbing height of the electrolyte on the electrode is read according to the graduated partition in the container, and the initial height H0 of the electrolyte is recorded. The height H of the electrode wetted by the electrolyte and the time T are regularly recorded, H-H0 is the climbing height of the electrolyte on the electrode in T time, H-H0 / T is the average climbing speed of the electrolyte on the electrode in T time, and then calculate the climbing height and climbing speed of the electrolyte on the electrode at different times; the use of the climbing height and speed of the electrolyte on the electrode per unit time to characterize the wetting ability of the electrolyte is achieved.
[0041] Among them, the greater the values of the climbing height and speed of the electrolyte on the electrode per unit time, the better the wettability of the electrode, and vice versa.
[0042] It should be noted that the test in the present application needs to be carried out in a constant humidity and temperature environment to reduce the impact of the volatilization of the electrolyte itself on the accuracy of the test results.
[0043] In a preferred embodiment, the plate material of the transparent container is a 5 mm thick transparent PVP plate, the length, width and height of the transparent container are set to 35 cm*20 cm*15 cm, the depth of the transparent container is 14.5 cm, the partition is located at about 1 / 4 of the width of the container, the length of the electrode hanging plate is 40 cm, and the bonding length of the flexible tape is 10-20 mm. The device of this embodiment is used as a device for the following tests.
[0044] In order to improve the test accuracy, the samples to be tested were set as 3 groups, one group of test samples included three electrode samples, and 3 groups of data were obtained at the same time. The unreasonable data were eliminated and the average value was taken as the test result. The wetting energy was characterized by the climbing rate and climbing height of the electrolyte.
[0045] Test Example 1
[0046] The testing process is as follows:
[0047] In the first step, the three electrode groups after hot pressing are placed in a vacuum oven at 90°C and dried for 24 hours.
[0048] In the second step, the dried electrodes are cut into electrode samples with a width of 25 mm and a length of 140 mm. Three samples are made in parallel for each group of electrodes, and then fixed on the same electrode hanging board with flexible tape.
[0049] The third step is to inject an appropriate amount of electrolyte into a container with a scale under a constant temperature and humidity environment. The electrolyte depth is 12mm, and then the electrode hanging plate that fixes the electrode sample is placed above the sample slot so that the electrode is partially immersed in the electrolyte. Start timing and record the initial height of the electrolyte infiltrating the electrode, which is 10mm.
[0050] The fourth step is to read the scale on the inner wall of the container and record the infiltration height of the electrolyte on the electrode at regular intervals. The infiltration height of the electrolyte on the electrode at 0, 5, 15, 30, 60, 120, and 180 minutes is recorded respectively. The test results are shown in Table 1.
[0051] Table 1
[0052]
[0053] In order to more intuitively compare the wettability of different electrodes to the same electrolyte, the test results are presented in the form of graphs, see Figure 5 , Figure 6 shown.
[0054] From the above illustrations or descriptions, it can be seen that the testing device of the utility model is transparent, and has a scale on the partition inside the transparent container, so that the climbing height of the electrolyte on the electrode can be easily read, and its wetting ability can be characterized by calculating the climbing speed and height of the electrolyte. The operation is convenient and the test results are relatively accurate.
[0055] In addition, the novel test device can also test multiple electrode samples at the same time, which can reduce the system error of the test, compare the test results more intuitively, and greatly improve the test efficiency.
[0056] The test device of the utility model has a simple test process and can quickly and accurately determine the wettability of different pole pieces to the electrolyte, providing a design basis for improving the wettability of the pole pieces to the electrolyte, and contributing to the rationalization of the design of the battery material system.
[0057] The above shows and describes the basic principles and main features of the utility model and the advantages of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model.
[0058] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. A device for testing the wettability of an electrode to an electrolyte, characterized in that: It comprises a transparent container with an opening on the top surface for containing electrolyte, a partition with scale arranged in the transparent container, and a pole piece hanging plate. The scale on the partition is arranged without interruption from left to right and is used to read the climbing height of the electrolyte on the pole piece. The partition divides the interior of the transparent container into two separated and non-communicating spaces. The pole piece hanging plate is used to hang the pole piece to be tested and then place it on the upper end of the partition.
2. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The pole piece hanging plate is horizontally arranged on the open top surface of the transparent container and is perpendicular to the partition plate; the pole piece hanging plate is in a T-shape after being connected to the partition plate.
3. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The length of the pole piece hanging plate is greater than the length of the transparent container.
4. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The electrode to be tested is bonded to the electrode hanging plate, and the electrode to be tested is perpendicular to the electrode hanging plate.
5. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The electrode to be tested and the electrode hanging plate are bonded and connected by a flexible adhesive tape.
6. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The transparent container is a rectangular cube container with an open top surface.
7. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The depth of the transparent container is 10-15 cm.
8. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The partition is fixed at a position of 1 / 2-1 / 4 of the width of the transparent container.
9. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that: The distance between adjacent scales is 1 mm.
10. The device for testing the wettability of an electrode to an electrolyte according to claim 1, characterized in that , the top of the partition is flush with the top of the transparent container.