Battery and battery testing device

Abstract

The utility model discloses a battery and a battery testing device, and relates to the technical field of battery testing, the battery comprises a shell and a laminated core, the laminated core is arranged in the shell; the laminated core comprises a positive pole piece, a negative pole piece, a reference electrode, a first diaphragm and a second diaphragm. The device can dynamically monitor the voltage change of the positive and negative electrodes of the battery in a lossless manner in the charging and discharging test process, not only can provide reference for the failure mechanism analysis of the battery, but also can predict the lithium precipitation risk in the charging and discharging process, and can improve the test stability and the manufacturing success rate, realize the multi-site high-precision monitoring of the lithium precipitation potential change, and improve the reliability of the battery. The lithium ion battery can be applied to the fields of blade lithium ion batteries and other secondary batteries.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery test technical field especially relates to a battery and battery testing arrangement. BACKGROUND

[0002] Lithium ion batteries have been widely used in electric vehicles, smartphones, laptops and other fields due to their high energy density, long cycle performance, lightweight, non-pollution, and low self-discharge rate. For example, Tesla's electric vehicles use lithium ion batteries as power sources, which have longer driving ranges and faster charging speeds. However, in practical applications, lithium ion batteries have the problem of lithium precipitation, which means that lithium metal is deposited on the negative electrode during charging and discharging, leading to a decrease in battery performance. Lithium precipitation can cause the battery's lifespan to be shortened, its safety to be reduced, and its capacity to be decreased.

[0003] To address the problem of lithium precipitation, evaluation methods mainly include electrochemical testing and characterization techniques. With the help of scanning electron microscopy (SEM), X-ray diffraction (XRD), and other techniques, the morphology and chemical composition of lithium precipitation products are analyzed to determine the health status of the battery. In addition, the principles and advantages of three-electrode evaluation of battery performance are also widely used to analyze lithium precipitation problems. This method adds an additional electrode to the battery, allowing direct observation of lithium precipitation during battery charging and discharging, thereby evaluating battery performance. The principles and advantages of three-electrode evaluation of battery performance enable accurate observation of the lithium precipitation process, helping researchers better understand battery performance and improve battery design and manufacturing. For example, researchers found that certain new electrolytes can effectively suppress lithium metal deposition and improve battery cycle life using the three-electrode evaluation method.

[0004] Currently, some researchers have attempted to apply the three-electrode evaluation method to actual lithium ion batteries. However, in practical operation, there are some difficulties and shortcomings in manufacturing. For example, since the three-electrode evaluation method requires modification of the battery, the manufacturing process is complex and can easily cause changes in the battery structure. In addition, due to the complexity of the three-electrode manufacturing process and the reference electrode, the efficiency of the final manufactured product is low. At the same time, the placement position of the reference electrode is relatively random or placed based on experience, and a single position cannot accurately characterize the lithium precipitation state of the stacked core. Therefore, although the three-electrode evaluation method has broad application prospects, there are still many challenges to overcome in practical applications. UTILITY MODEL CONTENT

[0005] The utility model aims to provide a battery and battery testing arrangement for solving the above technical problems.

[0006] The technical scheme adopted by the utility model is as follows:

[0007] A battery comprising a shell and a stack, the inside of the shell being provided with the stack;

[0008] The stack comprises positive electrode sheets, negative electrode sheets, reference electrodes, first separators and second separators, one positive electrode sheet is arranged between two adjacent negative electrode sheets, the second separators are arranged between the positive electrode sheets and the negative electrode sheets, the reference electrodes are arranged on the negative electrode sheets between two adjacent positive electrode sheets or on the positive electrode sheets, and the reference electrodes extend out of the shell.

[0009] Preferably, the shell comprises a shell body, a positive cover plate and a negative cover plate, the positive cover plate and the negative cover plate are mounted at both ends of the shell body, and the reference electrodes extend out of the shell body, the positive cover plate or the negative cover plate from the same side.

[0010] Further preferably, the shell body, the positive cover plate or the negative cover plate is provided with a lead-out hole.

[0011] Preferably, the battery further comprises positive and negative electrode tabs, the end of the positive electrode sheet is provided with the positive electrode tab, and the end of the negative electrode sheet is provided with the negative electrode tab.

[0012] Preferably, the first separator completely covers the negative electrode sheet or covers part of the negative electrode sheet.

[0013] Preferably, the second separator covers all the negative electrode sheets and the positive electrode sheets.

[0014] Preferably, the first separator partially covers the reference electrode and is fixed by a fixing member.

[0015] Further preferably, the positive cover plate and / or the negative cover plate is provided with a liquid injection hole.

[0016] Preferably, the battery is one of a square battery, a soft pack battery, a cylindrical battery or a blade lithium ion battery.

[0017] Preferably, at least two reference electrodes are arranged on the negative electrode sheet or the positive electrode sheet between each two adjacent positive electrode sheets.

[0018] Further preferably, the battery is a blade battery, and the reference electrodes extend out of the negative cover plate.

[0019] A battery testing device comprising the battery, the battery testing device comprising a testing cabinet, and the reference electrodes extend out of the shell and are connected to the testing cabinet.

[0020] The above technical solution has the following advantages or beneficial effects:

[0021] In this invention, by setting up a positive electrode, a negative electrode, a reference electrode, a first separator, and a second separator, the voltage changes of the positive and negative electrodes of the battery can be monitored non-destructively and dynamically during the charging and discharging test. This not only provides a reference for the analysis of battery failure mechanisms but also predicts the risk of lithium plating during charging and discharging. Furthermore, it can improve the stability of the test and the success rate of the fabrication, and achieve high-precision monitoring of lithium plating potential changes at multiple sites. It can be applied to blade lithium-ion batteries and other secondary battery fields. Attached Figure Description

[0022] Figure 1 This is an exploded schematic diagram of the battery in this utility model;

[0023] Figure 2 This is a schematic diagram of the reference electrode extending out of the negative electrode cover plate in this utility model;

[0024] Figure 3 This is a schematic diagram showing the distribution of the positive electrode, negative electrode, and second diaphragm in the cross-section of the stacked core in this utility model.

[0025] In the diagram: 1. Positive electrode; 2. Negative electrode; 3. Reference electrode; 4. First diaphragm; 5. Second diaphragm; 6. Positive electrode tab; 7. Negative electrode tab; 8. Negative electrode cover plate; 9. Lead-out hole; 10. Liquid injection hole; 11. Stacked core. Detailed Implementation

[0026] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of the utility model, it is to explain, unless another explicit provision and limitation, if the term "installation", "connection", "connect" should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrally connected;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be two elements inside the communication。For ordinary skilled in the art, the above-mentioned terms can be understood according to the specific meaning of the utility model.

[0029] Figure 1 It is the explosion schematic diagram of the battery in the utility model; Figure 2 It is the schematic diagram of reference electrode extending negative cover plate in the utility model; Figure 3 It is the distribution schematic diagram of positive pole piece, negative pole piece and second diaphragm in the utility model core section. Figures 1 to 3 As shown in the figure, a preferred embodiment is shown, showing a kind of battery, including shell and core 11, the inside of shell is provided with core 11.

[0030] Core 11 includes positive pole piece 1, negative pole piece 2, reference electrode 3, first diaphragm 4 and second diaphragm 5, one positive pole piece 1 is respectively arranged between two adjacent negative pole pieces 2, and the second diaphragm 5 is arranged between a plurality of positive pole pieces 1 and a plurality of negative pole pieces 2, a plurality of reference electrodes 3 are placed on the negative pole piece 2 between two adjacent positive pole pieces 1 by the first diaphragm 4, and a plurality of reference electrodes 3 extend out of the shell.In the embodiment, the number of positive pole piece 1, negative pole piece 2, reference electrode 3 and first diaphragm 4 is set to several, while the number of second diaphragm 5 can be one or several. Figure 3 As shown in the figure, when the second diaphragm 5 is provided with one, the second diaphragm 5 can be bent for many times, and the positive pole piece 1 and the negative pole piece 2 are arranged at the included angle position formed by the bending of the second diaphragm 5, so that the adjacent positive pole piece 1 and negative pole piece 2 can be separated by the second diaphragm 5, and the adjacent two positive pole pieces 1 or the adjacent two negative pole pieces 2 can also be separated from each other, and the number of negative pole pieces 2 is greater than the number of positive pole pieces 1, the two pole pieces located at the outermost side are negative pole pieces 2, and the two negative pole pieces 2 located at the outermost side do not have reference electrode 3.When the second diaphragm 5 is provided with several, the second diaphragm 5 is arranged between the adjacent positive pole piece 1 and negative pole piece 2, for separating the positive pole piece 1 and the negative pole piece 2.

[0031] Among them, refer to Figure 1As shown, the reference electrode 3 is provided in plurality, one end of the reference electrode 3 is provided on the negative electrode tab 2 and is isolated by the first diaphragm 4, and the other end of the reference electrode 3 penetrates through the shell. By providing the positive electrode tab 1, the negative electrode tab 2, the reference electrode 3, the first diaphragm 4 and the second diaphragm 5, the voltage change in the process of charging and discharging of the battery can be dynamically monitored without damage, which not only provides a reference for analyzing the failure mechanism of the battery, but also predicts the risk of lithium precipitation in the charging and discharging process. Unlike the single reference electrode 3 of the three-electrode stack core 11 in the past, the three-electrode system can improve the stability of the test, the success rate of the production and other advantages, realize multi-site high-precision monitoring of lithium precipitation potential change, and can be applied to the field of blade lithium ion battery and other secondary batteries. The material of the reference electrode 3 in the embodiment is insulating paint-wrapped gold wire, silver wire, copper wire or platinum wire, and the length and diameter of the reference electrode 3 can be set as needed. The length, height and width of the first diaphragm 4 and the second diaphragm 5 can also be set as needed.

[0032] Further, as a preferred embodiment, the shell includes a shell body 6, a positive electrode cover plate 7 and a negative electrode cover plate 8, the shell body 6 is provided with the positive electrode cover plate 7 and the negative electrode cover plate 8 at both ends, and the plurality of reference electrodes 3 extend out of the shell body 6, the positive electrode cover plate 7 or the negative electrode cover plate 8 from the same side. The battery in the embodiment can be selected as a blade battery, and the reference electrode 3 in the battery extends out of the negative electrode cover plate 8. In the embodiment, the shell body 6 is used to mount the stack core 11, and the positive electrode cover plate 7 and the negative electrode cover plate 8 are used to encapsulate both ends of the shell body 6. In the embodiment, the reference electrode 3 extending out of the negative electrode cover plate 8 is taken as an example for description, of course, in other embodiments, the reference electrode 3 can extend out of the positive electrode cover plate 7, or extend out of the side wall of the shell body 6, and the specific selection can be made as needed. It also includes a positive electrode tab 6 and a negative electrode tab 7, the end of the positive electrode tab 1 is provided with the positive electrode tab 6, and the end of the negative electrode tab 2 is provided with the negative electrode tab 7. Referring to Figure 1 As shown, the part of the end of the positive electrode tab 1 extending outwards forms the positive electrode tab 6, and the positive electrode tab 6 is not coated with active material, and the part of the end of the negative electrode tab 2 extending outwards forms the negative electrode tab 7, and the negative electrode tab 7 is not coated with active material.

[0033] In the embodiment, when the other end of the reference electrode 3 extends out of the negative electrode cover plate 8, the reference electrode 3 can be placed on the negative electrode cover plate 8 and protected by the adhesive tape.

[0034] Further, as a preferred embodiment, the shell body 6, the positive electrode cover plate 7 or the negative electrode cover plate 8 is provided with a lead-out hole 9. In the embodiment, the lead-out hole 9 is preferentially provided on the negative electrode cover plate 8, and a liquid injection hole 10 is provided on the positive electrode cover plate 7 and / or the negative electrode cover plate 8. Among them, the liquid injection hole 10 is preferentially provided on the positive electrode cover plate 7 and the negative electrode cover plate 8.

[0035] Furthermore, as a preferred embodiment, the first diaphragm 4 completely covers the negative electrode plate 2 or covers a portion of the negative electrode plate 2. In this embodiment, see [reference needed]. Figure 1 As shown, the first diaphragm 4 preferably covers a portion of the negative electrode plate 2, and several first diaphragms 4 are spaced apart. In other embodiments, only one first diaphragm 4 may be provided on each negative electrode plate 2. Several reference electrodes 3 are mounted on the negative electrode plate 2 through the first diaphragms 4, and the several reference electrodes 3 are arranged separately.

[0036] Furthermore, as a preferred implementation method, see [link to previous document]. Figure 3 As shown, the second diaphragm 5 comprises several segments connected in sequence, each segment arranged in a "Z" shape. The negative electrode 2 and the positive electrode 1 are positioned at the angle between the segments and, after hot pressing, form a stacked core 11. Figure 3 As shown, the second diaphragm 5 covers all the negative electrode plates 2 and positive electrode plates 1, and the two outermost negative electrode plates 2 are also covered by the second diaphragm 5.

[0037] Furthermore, as a preferred embodiment, the first diaphragm 4 partially covers the reference electrode 3 and is fixed by a fastener. The size of the first diaphragm 4 is larger than the diameter of the reference electrode 3, so that the reference electrode 3 can be completely covered, preventing the reference electrode 3 on the negative electrode plate 2 from being exposed. In this embodiment, the first diaphragm 4 covers the processed end position of the reference electrode 3 and can be fixed by a fastener to prevent movement. The fastener can be tape or other fixing device.

[0038] The shell 6 in the embodiment is an aluminum plastic film shell 6. In the process of preparing the blade battery three-electrode system in the embodiment, the reference electrode 3 is first pretreated, then the first diaphragm 4 is cut, then the lead-out hole 9 is arranged on the negative electrode cover plate 8, the positive electrode cover plate 7 or the shell 6, and the reference electrode 3 is prepared to be led out, then the laminated core 11 after hot pressing is disassembled, the glue on the laminated core 11 is removed by a blade, so that the laminated core 11 can be opened from the middle area, the pretreated reference electrode 3 and the first diaphragm 4 are placed on the negative electrode plate 2 in the inside of the laminated core 11, and the reference electrode 3 is led out with the help of the lateral adhesive tape. The opened laminated core 11 is placed in the original position, the laminated core 11 is restored by sticking the adhesive tape, the laminated core 11 in which the reference electrode 3 is placed is first welded with the cover plate, the reference electrode 3 is led out from the lead-out hole 9 after welding, the reference electrode 3 after being led out is placed on the negative electrode cover plate 8 and is protected by the adhesive tape, then normal film coating, shell entering, cover plate welding, peripheral welding and baking treatment are carried out, the laminated core 11 after baking is filled with glue, the reference electrode 3 is straightened and then filled with glue, the reference electrode 3 is placed on the negative electrode cover plate 8 again after the glue is dry and is protected by the adhesive tape, then the laminated core 11 is normally subjected to primary liquid injection, formation, secondary liquid injection and capacity grading treatment, and the reference electrode 3 can be led out through the lead-out hole 9 on the negative electrode cover plate 8 and is connected with the external test line.

[0039] The battery in the embodiment can be one of a square battery, a soft package battery, a cylindrical battery or a blade lithium ion battery, and can be selected as required.

[0040] In the embodiment, at least two reference electrodes 3 are arranged on the negative electrode plate 2 between each two adjacent positive electrode plates 1, and the number of the reference electrodes 3 can be selected as required.

[0041] On the basis of the above-mentioned embodiment, the utility model discloses a battery testing device, including the battery, and the battery testing device includes the test cabinet, and the reference electrode 3 is connected with the test cabinet after extending the shell. In the embodiment, the reference electrode 3 can be connected with the external test cabinet through the lead after extending the shell, and the lead and the test cabinet are connected through the test clamp. The test cabinet is mainly used for measuring the voltage, current and the like of the battery.

[0042] The above-mentioned is only the preferred embodiment of the utility model, and does not limit the implementation and protection scope of the utility model. For those skilled in the art, it should be realized that the scheme obtained by equivalent replacement and obvious change of the utility model specification and drawing content should be included in the protection scope of the utility model.

Claims

1. A battery, characterized by, The battery includes a shell and a stack core, and the stack core is arranged inside the shell; The stack core includes positive electrode sheets, negative electrode sheets, reference electrodes, first separators, and second separators. Each of the negative electrode sheets is arranged between two adjacent positive electrode sheets. The second separators are arranged between the positive electrode sheets and the negative electrode sheets. The reference electrodes are arranged on the negative electrode sheets between the positive electrode sheets or on the positive electrode sheets. The reference electrodes extend out of the shell.

2. The battery of claim 1, wherein, The shell includes a shell body, a positive electrode cover plate, and a negative electrode cover plate. The positive electrode cover plate and the negative electrode cover plate are arranged at both ends of the shell body. The reference electrodes extend out of the shell body, the positive electrode cover plate, or the negative electrode cover plate from the same side.

3. The battery of claim 2, wherein the cathode is a lithium cobalt oxide cathode. The shell body, the positive electrode cover plate, or the negative electrode cover plate is provided with a lead-out hole.

4. The battery of claim 1, wherein the cathode comprises a lithium metal oxide. The first separator completely covers the negative electrode sheet or covers a part of the negative electrode sheet.

5. The battery of claim 1, wherein the cathode comprises a lithium metal oxide. The second separator covers all the negative electrode sheets and the positive electrode sheets.

6. The battery of claim 1, wherein the cathode comprises a lithium metal oxide. The first separator partially covers the reference electrode and is fixed by a fixing member.

7. The battery of claim 1, wherein the cathode comprises a lithium metal oxide. The battery is one of a square battery, a soft package battery, a cylindrical battery, or a blade lithium ion battery.

8. The battery of claim 1, wherein the cathode comprises a lithium metal oxide. At least two reference electrodes are arranged on each of the negative electrode sheets between the positive electrode sheets or on each of the positive electrode sheets.

9. The battery of claim 2, wherein the cathode comprises a lithium cobalt oxide. The battery is a blade battery, and the reference electrodes extend out of the negative electrode cover plate.

10. A battery testing device comprising the battery of any one of claims 1-9, wherein, The battery testing device includes a test cabinet, and the reference electrodes extend out of the shell and are connected to the test cabinet.

Images