Measuring device for detecting deformation displacement of battery

Abstract

The embodiment of the utility model provides a measuring device for detecting deformation displacement of a battery, and relates to the technical field of battery detection. The measuring device for detecting the deformation displacement of the battery comprises a capacitance tester, a lower polar plate placed on the upper surface of the battery and an upper polar plate suspended above the lower polar plate, the position of the upper polar plate is fixed, the lower polar plate is movable, and an air medium is arranged between the upper polar plate and the lower polar plate. The upper pole plate and the lower pole plate are respectively connected with a capacitance tester. The measuring device for detecting the deformation displacement of the battery can detect the displacement generated by volume expansion and shrinkage of the battery, and is high in sensitivity and accuracy.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and more specifically, to a measuring device for detecting battery deformation displacement. Background Technology

[0002] Lithium-ion batteries exhibit regular volume expansion and contraction during charge-discharge cycles: during charging, as lithium is inserted into the negative electrode, the thickness of the negative electrode increases, and the battery volume expands; during discharging, as lithium is delithiated from the negative electrode, the thickness of the negative electrode decreases, and the battery volume contracts. Detecting the volume expansion and contraction during lithium-ion battery cycling is of great significance for revealing the mechanisms of lithium-ion battery cycle life degradation and cycle life extension.

[0003] Currently, devices for detecting displacement caused by the volume expansion of lithium-ion batteries typically include two clamping plates that hold the lithium-ion battery in the middle. As the lithium-ion battery expands in volume during cycling, the displacement caused by the battery volume expansion is obtained by detecting the displacement between the two clamping plates.

[0004] This device requires applying pressure to the battery using pressure plates during testing, ensuring a tight seal between the plates and the lithium-ion battery surface. Displacement only occurs when the pressure exerted by the battery expansion on the pressure plates exceeds the applied pressure, allowing for the measurement of displacement caused by battery volume expansion. Therefore, this device cannot measure displacements below the applied pressure, limiting its sensitivity. Furthermore, when using guide rods to connect the two pressure plates and guide the displacement direction, the friction between the pressure plates and the guide rods further restricts the accuracy of displacement measurement. Utility Model Content

[0005] The purpose of this application is to provide a measuring device for detecting battery deformation displacement, which can detect the displacement caused by battery volume expansion and contraction, and has high sensitivity and accuracy.

[0006] This application provides a measuring device for detecting battery deformation displacement, which includes a capacitance tester, a lower electrode plate placed on the upper surface of the battery, and an upper electrode plate suspended above the lower electrode plate. The position of the upper electrode plate is fixed, the lower electrode plate is movable, and the space between the upper electrode plate and the lower electrode plate is air. The upper electrode plate and the lower electrode plate are respectively connected to the capacitance tester.

[0007] In the above implementation process, the measuring device includes a parallel plate capacitor composed of an upper electrode plate, a lower electrode plate, and a capacitance tester. During use, the lower electrode plate is placed on the upper surface of the lithium-ion battery, while the upper electrode plate is suspended above the lower electrode plate and fixed in position. When the lithium-ion battery deforms (expands or contracts in volume), the lower electrode plate displaces along with the upper surface of the battery, changing the distance between the lower and upper electrode plates and thus altering the capacitance value of the parallel plate capacitor. Therefore, by detecting the change in capacitance value using the capacitance tester, the displacement caused by the battery's volume expansion and contraction can be detected. The upper electrode plate in this measuring device does not contact the battery, and the lower electrode plate applies extremely low pressure to the battery and can move in real time with the battery's expansion and contraction. Therefore, it can detect the minute expansion and contraction of the lithium-ion battery during cycling, exhibiting high sensitivity. Furthermore, the lower electrode plate interacts almost no with other objects during displacement, eliminating the problem of friction limiting test accuracy and resulting in high accuracy.

[0008] In one possible implementation, the lower surface of the lower electrode plate is provided with a surrounding plate that matches the upper surface of the battery, the surrounding plate and the lower electrode plate together form a receiving cavity, and the top of the battery is embedded in the receiving cavity.

[0009] In the above implementation process, the lower electrode plate can be stably placed on the battery and move synchronously with the upper surface of the battery through the function of the surrounding plate, and the pressure added to the battery is small, and the impact on the sensitivity detection is small.

[0010] In one possible implementation, the enclosure is made of an insulating material.

[0011] In the above implementation process, the enclosure is made of insulating material, which can reduce the impact on the lower electrode plate, thereby reducing the impact on the detection sensitivity.

[0012] In one possible implementation, a bracket for mounting the upper electrode plate is also included, with the upper electrode plate fixedly mounted on the bracket.

[0013] In the above process, the upper electrode plate can be suspended and fixed by means of a bracket.

[0014] In one possible implementation, the support is made of an insulating material.

[0015] In the above implementation process, the support is made of insulating material to ensure the normal operation of the parallel plate capacitor.

[0016] In one possible implementation, the support includes a horizontal bar and a vertical bar connected together, the horizontal bar being disposed above the upper electrode plate, the vertical bar being disposed on one side of the upper electrode plate and the lower electrode plate, the upper electrode plate being suspended from one end of the horizontal bar, and the other end of the horizontal bar being connected to the vertical bar.

[0017] In the above implementation process, the combination of horizontal and vertical bars allows the upper electrode plate and other components to be installed on the same worktable.

[0018] In one possible implementation, it further includes a test bench with a placement area for placing the battery, and the lower electrode plate is mounted on the test bench via a bracket.

[0019] In one possible implementation, the placement area is provided with a positioning element for limiting the translation of the battery.

[0020] In the above implementation process, the positioning component reduces the movement of the battery in the placement area, so as to accurately detect the displacement of the upper surface of the battery, thereby obtaining the displacement caused by the deformation of the battery.

[0021] In one possible implementation, the upper electrode plate is made of metal and has a thickness of 5μm-10μm.

[0022] The lower electrode plate is made of metal and has a thickness of 5μm-10μm.

[0023] In the above implementation process, the sensitivity of the measuring device can be controlled by adjusting the thickness of the lower electrode (micrometer level) in response to the minute expansion and contraction of the lithium-ion battery during cycling.

[0024] In one possible implementation, the upper electrode plate and the lower electrode plate are arranged opposite to each other, and the upper electrode plate is arranged horizontally. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a measuring device provided in an embodiment of this application when detecting battery deformation displacement.

[0027] Icons: 001-Lithium-ion battery; 110-Lower electrode plate; 120-Upper electrode plate; 130-Capacitance tester; 140-Support; 150-Test platform; 161-First lead wire; 162-Second lead wire. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application 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 application.

[0033] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] First Embodiment

[0036] Please refer to Figure 1This embodiment provides a measuring device for detecting battery deformation displacement, comprising a capacitance tester 130, a lower electrode plate 110 placed on the upper surface of the battery, and an upper electrode plate 120 suspended above the lower electrode plate 110. The upper electrode plate 120 is fixed in position, while the lower electrode plate 110 is movable. Air is the medium between the upper electrode plate 120 and the lower electrode plate 110. The upper electrode plate 120 and the lower electrode plate 110 are respectively connected to the capacitance tester 130. Here, "battery" refers to the object under test, and "upper surface of the battery" refers to the battery in a specific placement state during testing. The capacitance tester 130 is an instrument used to detect the capacitance value between the upper electrode plate 120 and the lower electrode plate 110.

[0037] In some embodiments of this application, the upper electrode 120 is made of metal and has a thickness of 5μm-10μm; the lower electrode 110 is also made of metal and has a thickness of 5μm-10μm. In this embodiment, the upper electrode 120 is made of copper and has a thickness of 5μm; the lower electrode 110 is also made of copper and has a thickness of 5μm. The lower electrode 110 is electrically connected to the capacitance tester 130 via a first wire 161, and the upper electrode 120 is electrically connected to the capacitance tester 130 via a second wire 162.

[0038] In some embodiments of this application, the upper electrode plate 120 and the lower electrode plate 110 are arranged opposite to each other, and the upper electrode plate 120 is arranged horizontally. In this embodiment, the battery to be tested is a lithium-ion battery 001. When using the measuring device for testing, the lower electrode plate 110 is placed on the upper surface of the lithium-ion battery 001 and is in contact with each other (at least the middle area of ​​the lower electrode plate 110 is in contact with the upper surface of the lithium-ion battery 001). The lower electrode plate 110 is also initially arranged horizontally, opposite to the upper electrode plate 120 and parallel to each other.

[0039] To improve the stability of the lower electrode plate placed on the upper surface of the lithium-ion battery 001, in some embodiments of this application, the lower surface of the lower electrode plate 110 is provided with a surrounding plate that matches the upper surface of the lithium-ion battery 001. The surrounding plate and the lower electrode plate 110 together form a receiving cavity, and the top of the lithium-ion battery 001 is embedded in the receiving cavity. The surrounding plate is made of an insulating material, such as plastic. In this embodiment, the lower electrode plate 110 is not provided with a surrounding plate or other positioning components. The lithium-ion battery 001 is placed flat with the tabs facing one side. The upper surface of the battery is the side surface of the lithium-ion battery 001, and the area of ​​this side surface is larger than the area of ​​the lower electrode plate 110. The lower electrode plate 110 can be directly placed in the middle of the side surface of the lithium-ion battery 001 and maintain a stable horizontal state.

[0040] In some embodiments of this application, a bracket 140 for mounting the upper electrode plate 120 is also included. The upper electrode plate 120 is fixedly mounted on the bracket 140, and the bracket 140 is made of an insulating material. In one embodiment, the bracket 140 includes a horizontally arranged crossbar and a vertically arranged vertical bar connected together. The crossbar is positioned above the upper electrode plate 120, and the vertical bar is positioned on one side of the upper electrode plate 120 and the lower electrode plate 110. The upper electrode plate 120 is suspended from one end of the crossbar, the other end of the crossbar is connected to the top of the vertical bar, and the bottom end of the vertical bar is fixed to a testing platform. In other embodiments, the bracket 140 may also adopt other structural forms or be fixed in other locations, such as the upper electrode plate 120 being fixedly suspended from the ceiling via the bracket 140.

[0041] In some embodiments of this application, it further includes a test stage 150, on which a placement area for placing the lithium-ion battery 001 is provided, and the lower electrode plate 110 is mounted on the test stage 150 via a bracket 140. To improve the positioning effect of the lithium-ion battery 001, a positioning element for limiting battery translation can also be provided in the placement area. To detect battery deformation displacement, the positioning element cannot restrict the vertical movement of the lithium-ion battery 001. Exemplarily, the positioning element includes suction cups dispersed around the battery, used to adsorb the sides of the battery, and the suction cups are mounted on the test stage 150 via a mounting member; or the positioning element is a baffle disposed around the battery.

[0042] To facilitate a further understanding of the measuring device in the embodiments of this application, the working principle and testing method of the measuring device are described below.

[0043] The measuring device is based on a parallel-plate capacitor, and the corresponding formula for its principle is as follows:

[0044] Formula 1:

[0045] Formula 2:

[0046] Formula 3:

[0047] Where C: capacitance (F); ε r k: Dielectric constant of the medium (F / m); k: Electrostatic constant (N·m) 2 / C 2 ); π: Pi; d: Distance between the two plates of a parallel-plate capacitor (m); S: Surface area of ​​the plates (m²) 2 ).

[0048] As can be seen from the above formula, the capacitance C of a parallel plate capacitor is inversely proportional to the distance d between the two plates (Formula 2). When the distance d changes, the capacitance C of the parallel plate capacitor will also change accordingly. Therefore, the expansion or contraction of the lithium-ion battery 001 during cycling causes a change Δd in the distance d of the parallel plate capacitor, and a corresponding change ΔC in the capacitance C of the parallel plate capacitor. Thus, the correspondence between Δd and ΔC is established (Formula 3).

[0049] The measuring device is based on a parallel-plate capacitor, comprising two plates: a lower plate 110 and an upper plate 120, with air as the dielectric. The testing method using the measuring device is as follows:

[0050] Building such Figure 1 The structure shown involves placing the lithium-ion battery 001 to be tested in the placement area of ​​the horizontal test platform 150, then placing the lower electrode plate 110 on the upper surface of the lithium-ion battery 001, and ensuring that the suspended upper electrode plate and the lower electrode plate are opposite each other and both are horizontally positioned. The lower electrode plate and the upper electrode plate are connected to the capacitance tester 130 through the first wire 161 and the second wire 162, respectively. The capacitance value of the measuring device is adjusted to C0 and the spacing is adjusted to d0.

[0051] The lithium-ion battery 001 is subjected to charge-discharge cycle testing. During the test, the upper electrode plate 120 remains stationary and horizontal, while the lower electrode plate 110 moves with the lithium-ion battery 001. The capacitance value measured by the capacitance tester 130 is recorded at a certain frequency. The general process is as follows: The battery is charged at a certain rate to the cutoff voltage. During this process, the volume of the lithium-ion battery 001 expands, and the distance between the upper electrode plate 120 and the lower electrode plate 110 decreases from d0 to d2. Correspondingly, the capacitance value increases from C0 to C2. After charging is completed and the battery is allowed to rest, the lithium-ion battery 001 is discharged at a certain rate to the cutoff voltage. During this process, the volume of the lithium-ion battery 001 shrinks, and the distance between the upper electrode plate 120 and the lower electrode plate 110 decreases from d2 to d1. Correspondingly, the capacitance value decreases from C2 to C1. The above process is repeated. Therefore, when the capacitance value detected by the capacitance tester 130 gradually decreases, it indicates that the lithium-ion battery 001 is in a contracted state, and the contracted displacement generated by the lithium-ion battery 001 during the cycle can be calculated by the difference in capacitance value; when the detected capacitance value gradually increases, it indicates that the lithium-ion battery 001 is in an expanded state, and the expanded displacement generated by the lithium-ion battery 001 during the cycle can be calculated by the difference in capacitance value.

[0052] In summary, the measuring device for detecting battery deformation displacement according to the embodiments of this application can detect the displacement caused by battery volume expansion and contraction, and has high sensitivity and accuracy.

[0053] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A measuring device for detecting battery deformation displacement, characterized in that, It includes a capacitance tester, a lower electrode plate placed on the upper surface of the battery, and an upper electrode plate suspended above the lower electrode plate. The position of the upper electrode plate is fixed, while the lower electrode plate is movable. The space between the upper electrode plate and the lower electrode plate is air. The upper electrode plate and the lower electrode plate are respectively connected to the capacitance tester.

2. The measuring device for detecting battery deformation displacement according to claim 1, characterized in that, The lower surface of the lower electrode plate is provided with a surrounding plate that matches the upper surface of the battery. The surrounding plate and the lower electrode plate together form a receiving cavity, and the top of the battery is embedded in the receiving cavity.

3. The measuring device for detecting battery deformation displacement according to claim 2, characterized in that, The enclosure is made of insulating material.

4. The measuring device for detecting battery deformation displacement according to claim 1, characterized in that, It also includes a bracket for mounting the upper electrode plate, the upper electrode plate being fixedly mounted on the bracket.

5. The measuring device for detecting battery deformation displacement according to claim 4, characterized in that, The bracket is made of insulating material.

6. The measuring device for detecting battery deformation displacement according to claim 4, characterized in that, The support includes a horizontal bar and a vertical bar connected together. The horizontal bar is located above the upper electrode plate, and the vertical bar is located on one side of the upper electrode plate and the lower electrode plate. The upper electrode plate is suspended from one end of the horizontal bar, and the other end of the horizontal bar is connected to the vertical bar.

7. The measuring device for detecting battery deformation displacement according to claim 1 or 4, characterized in that, It also includes a test stand, which has a placement area for placing the battery, and the lower electrode plate is mounted on the test stand by a bracket.

8. The measuring device for detecting battery deformation displacement according to claim 7, characterized in that, The placement area is provided with positioning elements to restrict the translation of the battery.

9. The measuring device for detecting battery deformation displacement according to claim 1, characterized in that, The upper electrode plate is made of metal and has a thickness of 5μm-10μm. The lower electrode plate is made of metal and has a thickness of 5μm-10μm.

10. The measuring device for detecting battery deformation displacement according to claim 1, characterized in that, The upper and lower electrode plates are arranged opposite to each other, and the upper electrode plate is arranged horizontally.

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