Cell short circuit test device and test method

Abstract

The invention relates to the technical field of battery testing, and particularly provides a battery cell short circuit testing device and testing method. The device comprises a device body, a gas control assembly and a test circuit. An opening capable of being opened and closed is formed in the device main body, and when the opening is closed, a closed test cavity for accommodating a to-be-tested battery cell is formed in the device main body. The test surface of the to-be-tested cell is exposed in the test cavity, and the test surface is a non-planar surface. And the gas control assembly controls the gas pressure in the test cavity. The test circuit comprises a test probe electrically connected with the to-be-tested cell. According to the device and the method provided by the invention, the problem that uniform pressurization on a non-plane is difficult to realize during the short-circuit test of the battery cell is solved, nondestructive uniform pressurization is realized through the pressure of the gas medium in the cavity, the short-circuit test can be completed on the premise of not damaging the structure of the battery cell, and the damage of physical contact to the battery cell is avoided. The testing efficiency and accuracy are high, and the testing error is smaller.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to a battery cell short-circuit testing device and a testing method. Background Art

[0002] During the manufacturing process, batteries can easily become contaminated with metal debris, burrs, welding defects, and dust particles. These impurities can create a potential short-circuit risk, potentially causing a safety incident under unusual external forces. Therefore, short-circuit testing is a key method for evaluating battery safety performance. By applying pressure to ensure full contact between the positive and negative electrodes and the separator inside the battery, and then testing for any abnormalities, the risk of a battery short circuit can be determined.

[0003] Cylindrical batteries are widely used in portable electronic devices and electric vehicles due to their high energy density and excellent cycle life. However, it is currently difficult to uniformly pressurize the sides of cylindrical battery cells, making it impossible to effectively screen out defective cells through short-circuit testing. Summary of the Invention

[0004] The embodiments of the present invention provide a battery cell short circuit testing device and a testing method, which at least solve the problem that it is difficult to achieve uniform pressurization on a non-planar surface during battery cell short circuit testing.

[0005] In a first aspect, the present invention provides a battery short circuit test device, which includes: A device body having an openable and closable opening, wherein when the opening is closed, the interior of the device body forms a sealed test cavity for accommodating the battery cell to be tested; a test surface of the battery cell to be tested is exposed in the test cavity, wherein the test surface is non-planar; a gas control assembly, the gas control assembly controlling the gas pressure in the test chamber; A test circuit includes a test probe electrically connected to the battery cell to be tested.

[0006] The battery short circuit testing device provided by the embodiment of the present invention also includes a fixing component; The battery cell to be tested includes two end surfaces that are oppositely arranged and lead out the tabs, and the test surface; the test surface connects the two end surfaces; the fixing assembly fixes the battery cell to be tested in the test cavity along the direction in which the two end surfaces are oppositely arranged.

[0007] The present invention provides a battery short circuit test device according to an embodiment of the present invention, wherein the fixing assembly includes a pressure member and a substrate; One end surface of the battery cell to be tested is arranged on the substrate through the test probe, and the other end surface is in contact with the pressure-applying member through the test probe; A pressure sensor is also provided on the substrate, and the pressure sensor is used to feed back the pressure exerted on the battery cell to be tested to the pressure applying member.

[0008] In the battery cell short circuit testing device provided by an embodiment of the present invention, the pressure-applying member is a sealing cover of the opening, and the sealing cover is sealed to the opening.

[0009] In the battery cell short circuit test device provided by the embodiment of the present invention, the battery cell to be tested is a cylindrical wound battery cell, and a support member is further provided in the winding hole of the battery cell to be tested, and both ends of the support member extend beyond the end surface of the battery cell to be tested; The first end of the support member is arranged on the base plate; the second end is installed in the avoidance hole of the pressure member, and the avoidance hole is a blind hole.

[0010] In the battery cell short circuit test device provided by the embodiment of the present invention, the second end of the support member is configured as a cone, and the tip of the cone is configured as an arc surface; And / or, the extension length of the portion of the second end of the support member extending beyond the test probe is greater than or equal to 5 mm.

[0011] The present invention provides a battery cell short-circuit testing device in which the end face of the lead-out tab of the battery cell to be tested abuts against the test probe of corresponding polarity to electrically connect the tab and the test probe; the edge of the test probe extends beyond the periphery of the battery cell to be tested.

[0012] The battery short circuit test device provided by the embodiment of the present invention, the gas control component includes a vacuum pipe, a gas input pipe and a gas recovery pipe; The vacuuming pipe is in communication with the test cavity and is used to vacuum the test cavity; The gas input pipe is in communication with the test chamber and is used to input a gas medium into the test chamber, and the density of the gas medium is consistent at all locations; The gas recovery pipe is in communication with the test chamber and is used to extract gas from the test chamber; A pressure sensor is also provided in the test chamber, and the pressure sensor is used to feed back the gas pressure in the test chamber to the gas control component.

[0013] In a second aspect, the present invention also provides a method for testing a short circuit of a battery cell, comprising the following steps: Placing the battery cell to be tested in a sealed test cavity of the device body, exposing the test surface of the battery cell to be tested to the test cavity; Electrically connecting the test circuit to the battery cell to be tested; Filling the test chamber with a gas medium through a gas control component so that the air pressure in the test chamber reaches a first preset pressure; wherein the gas medium is set to be an inert gas or pure air; The voltage or current of the battery cell to be tested is detected by a test circuit to determine whether the battery cell to be tested is short-circuited.

[0014] The present invention provides a method for testing a short circuit of a battery cell, wherein the battery cell to be tested is placed in a sealed test cavity of a device body, and includes: Opening the opening of the device body, placing the battery cell to be tested on the substrate in the test cavity, with the support member passing through the winding hole of the battery cell to be tested; Align the avoidance hole of the pressure-applying member with the second end of the support member extending beyond the battery cell to be tested, seal the pressure-applying member with the opening, and apply pressure toward the substrate; The pressure sensor of the substrate feeds back pressure to the pressure applying member until the pressure applied by the pressure applying member is controlled to be a second preset pressure.

[0015] The battery cell short circuit testing method provided by the embodiment of the present invention further includes, before filling the test cavity with a gas medium through a gas control component, extracting the air in the test cavity through the gas control component.

[0016] The battery cell short circuit test method provided by the embodiment of the present invention, after determining whether the battery cell to be tested is short-circuited, the method further includes: releasing the gaseous medium in the test chamber, or recovering the gaseous medium in the test chamber through a gas control component; When the gas pressure in the test cavity is balanced with the atmospheric pressure, the opening of the device body is opened and the battery cell to be tested is taken out from the test cavity.

[0017] The battery cell short-circuit test device and method provided by the present invention solve the problem of difficulty in achieving uniform pressurization on non-planar surfaces during battery cell short-circuit testing. A sealed test chamber is provided for placing the battery cell to be tested and exposing the non-planar test surface. Non-destructive uniform pressurization is achieved through the air pressure within the chamber. This allows for the short-circuit test to be completed without damaging the battery cell structure, thus avoiding damage to the cell due to physical contact. This results in higher test efficiency and accuracy, with smaller test errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1This is a schematic diagram of the use of the battery short-circuit testing device in Example 1 of the present invention.

[0019] Figure 2 This is a schematic diagram of assembling a battery cell before use in the battery cell short circuit testing device in Example 1 of the present invention.

[0020] Figure 3 This is a schematic diagram of assembling a pressure piece of the battery cell short circuit test device in Example 1 of the present invention before use.

[0021] Figure 4 This is a flow chart of the battery cell short circuit testing method in Example 2 of the present invention.

[0022] The above drawings include the following reference numerals: 1. Device body; 11. Opening; 12. Test chamber; 13. Shell; 14. Cover; 2. Battery cell to be tested; 21. Test surface; 22. End face; 2201. Tab; 3. Gas control assembly; 31. Vacuum pipe; 32. Gas input pipe; 33. Gas recovery pipe; 34. Purifier; 4. Test probe; 5. Fixing assembly; 51. Pressure member; 5101. Avoidance hole; 52. Substrate; 6. Support member; 61. First end; 62. Second end; 7. Pressure sensor. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary, not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0026] Due to the limitation of the surface structure, it is difficult to apply uniform pressure on the surface during short circuit testing. Figures 1 to 3 As shown, a first embodiment of the present invention provides a battery cell short circuit test device, which includes a device body 1, a gas control component 3, and a test circuit. A battery cell 2 to be tested is placed in a test chamber 12 of the device body 1. The gas control component 3 controls the gas pressure in the sealed test chamber 12 within the device body 1, thereby pressurizing the battery cell 2 to be tested. The test circuit then detects the short circuit condition within the battery cell 2 to screen out defective batteries.

[0027] Specifically, the device body 1 is provided with an openable and closable opening 11, which is configured to have two states: open and closed. When the opening 11 is open, the space inside the device body 1 is connected to the external atmosphere. The battery cell 2 to be tested can be placed inside the device body 1 through the open opening 11, or can be removed from the interior of the device body 1 through the open opening 11. When the opening 11 is closed, a sealed test chamber 12 is formed inside the device body 1. When the battery cell short-circuit test device is in use, the test chamber 12 is used to accommodate the battery cell 2 to be tested.

[0028] In some embodiments, the opening 11 is provided on a side surface of the device body 1. Depending on the actual layout of the device body 1, the opening 11 can be provided on one or more of the top, bottom, or side surfaces of the device body 1. In other embodiments, the device body 1 can be configured as at least two separate parts that can be assembled. When the separate parts are assembled, they are sealed together to form a test cavity 12. The side of the at least two separate parts that are assembled after being disassembled forms an opening 11 for accessing and placing the battery cell 2 to be tested.

[0029] In the embodiment of the present invention, preferably, referring to Figures 1 to 3As shown, the opening 11 is provided at the top of the device body 1 and is opened and closed by a pressure member 51 as a sealing cover. The opening 11 in the first embodiment is provided to facilitate the removal and placement of the battery cell 2 to be tested, and the sealing cover can simultaneously close the opening 11 and fix the battery cell 2 to be tested.

[0030] The contour shape and size of the opening 11 can be set according to the actual size requirements of the battery cell 2 to be tested. In the embodiment of the present invention, the opening 11 is not specifically limited, so long as it can be placed in and out of the battery cell 2 to be tested, can be closed and opened, and meet the actual requirements of other battery cell short-circuit tests.

[0031] Short-circuit testing is required at many stages of battery production to eliminate short-circuited cells and ensure product yield and quality. Short-circuit testing of cells after winding or lamination is particularly important. This is because defects such as misaligned pole pieces, wrinkled and damaged separators during winding, and burrs on the pole piece edges piercing the separator during lamination are common. These can easily lead to direct contact between the positive and negative poles, causing a short circuit, self-discharge, heat generation, and even fire. Furthermore, the subsequent assembly process for winding and lamination is complex, and failure to promptly detect and address short-circuit issues can result in significant cost and safety risks.

[0032] In the current short-circuit test process, the flat surface of the wound and laminated battery cell is mechanically pressurized, and the test is performed by directly pressing the pressure workpiece against the flat large surface of the battery cell. However, the spiral winding process will form at least some non-planar structures, including cylindrical curved surfaces, prismatic folded corners, and other irregular curved surfaces. The lamination process can also produce non-planar structures due to the cutting accuracy of the electrode edges, alignment errors, and diaphragm folding marks, including slight surface undulations, folded corners, and localized uneven areas.

[0033] For the aforementioned non-planar structures, the related mechanical pressurization methods are difficult to achieve uniform pressurization. Therefore, the first embodiment of the present invention provides a battery cell short-circuit test device. During a short-circuit test, the test surface 21 of the battery cell 2 to be tested is exposed in the enclosed test cavity 12. The test surface 21 is configured to be non-planar.

[0034] The present invention controls and adjusts the gas pressure within the test chamber 12 through the gas control assembly 3, uniformly applying pressure to the test surface 21 of the cell 2 under test. This pressure can accommodate complex curved surfaces and various non-planar structures. This uniform pressure within the test chamber 12 is combined with the test probe 4 of the test circuit, which electrically connects the test probe 4 to the cell 2 under test for a short-circuit test. This provides a more uniform pressure than mechanical pressure and avoids misalignment of the cell structure caused by rigid abutment.

[0035] Reference Figure 1 and Figure 2As shown, the battery cell 2 to be tested includes two end surfaces 22 arranged opposite to each other, and a test surface 21 located between the two end surfaces 22. The test surface 21 connects the two end surfaces 22, and the two end surfaces 22 respectively lead to tabs 2201 of opposite polarity. The battery cell short circuit test device also includes a fixing assembly 5. The fixing assembly 5 fixes the battery cell 2 to be tested along the direction in which the two end surfaces 22 of the battery cell 2 to be tested are arranged opposite to each other, thereby fixing the battery cell 2 to be tested within the test cavity 12.

[0036] Specifically, refer to Figure 2 As shown, the fixing assembly 5 includes a pressure member 51 and a base plate 52. One end surface 22 of the battery cell 2 to be tested is set on the base plate 52 through the test probe 4, and the other end surface 22 of the battery cell 2 to be tested contacts the pressure member 51 through the test probe 4.

[0037] It should be noted that, in some embodiments, the two end faces 22 of the battery cell to be tested 2 are arranged relative to each other in the vertical direction. In other embodiments, the two end faces 22 of the battery cell to be tested 2 can also be arranged relative to each other in other directions, and the two end faces 22 are fixed by a fixing component 5. That is to say, the battery cell to be tested 2 can be set to any posture that can be fixed and expose the test surface 21 in the test cavity 12. According to Pascal's law, when any point in an incompressible static fluid is subjected to an external force to generate a pressure increase, this pressure increase is instantaneously transmitted to all points in the fluid and remains unchanged. The core of Pascal's law is the uniform transmission of pressure inside a closed fluid. The pressure transmission is instantaneous and non-directional, and will be transmitted to all parts of the fluid and the container wall at the same time. In the closed environment of the test cavity 12, the fluid is at rest without macroscopic flow. After the gas medium is inflated and stabilized, its pressure is evenly distributed in the test cavity 12, and the pressure of each point in the gas medium is equal in all directions. When the test surface 21 is fully exposed, all parts of its surface are in contact with the gas medium in the test chamber 12. After reaching equilibrium, the gas pressure on all parts of the test surface 21 is equal, meeting the short-circuit test requirement of uniform pressurization of the test surface 21.

[0038] Preferably, in the first embodiment of the present invention, the opening 11 is provided on the top surface of the device body 1, and the battery cell 2 to be tested is placed vertically downward into the test cavity 12. The two end surfaces 22 of the battery cell to be tested are arranged relative to each other in the vertical direction, and the pressure member 51 and the base plate 52 are arranged relative to each other in the vertical direction to fix the battery cell to be tested 2. In this case, the force-applying fixing direction of the fixing assembly 5 is consistent with the direction of gravity of the battery cell to be tested 2 after it is placed. Compared with other directions, the fixing assembly 5 only needs to adjust the height in the vertical direction to achieve force clamping and release, making it easier to assemble.

[0039] Further, refer to Figure 2As shown, the pressure member 51 also serves as a sealing cover for closing the opening 11 of the device body 1. During a short-circuit test, the pressure member 51 applies pressure to the test cell 2, along the direction in which the two end faces 22 of the test cell 2 face each other, toward the substrate 52. While adjusting and applying pressure to the test cell 2, the pressure member 51 acts as a sealing cover to seal the opening 11 of the device body 1, maintaining a sealed connection with the opening 11.

[0040] In some embodiments, the outer circumference of the pressure member 51 is threadedly engaged with the opening 11 of the device body 1, the outer circumference of the pressure member 51 is provided with an external thread, and the opening 11 of the device body 1 is provided with an internal thread. The device body 1 can also be set as a structure in which a shell 13 and a cover plate 14 are spliced ​​together, the opening 11 is provided on the cover plate 14, and the length of the internal thread of the opening 11 is related to the thickness of the cover plate 14. The longer the thread when the pressure member 51 is threadedly engaged with the opening 11, the longer the effective screwing length that can be engaged with each other, the larger the space that the pressure member 51 can adjust in the screwing direction, and the larger the adjustment range of the force applied to the battery cell 2 to be tested. In other embodiments, the pressure member 51 can also be set as an adjustable plunger structure or a snap-on structure with an elastic element such as a spring sheet, etc., to meet the requirements of a sealed connection with the opening 11 and the ability to adjust the depth of entry into the opening 11. In order to improve the sealing connection effect, a sealing ring can also be provided at the position where the pressure member 51 abuts the opening 11 to enhance the airtightness of the test chamber 12.

[0041] Furthermore, a pressure sensor is also provided on the substrate 52. When performing a short circuit test, refer to Figure 2 As shown, the pressure member 51, the test probe 4, the battery cell to be tested 2, the substrate 52 and the pressure sensor on the substrate 52 are arranged in a straight line. In a balanced state, according to Newton's third law, the pressure applied to the test probe 4 by the pressure member 51 and the pressure transmitted to the battery cell to be tested 2 by the test probe 4 are equal to the pressure applied to the substrate 52 and the pressure sensor after the battery cell to be tested is pressurized. There is no other external force interference in the direction in which the two end faces 22 of the battery cell are relatively set in the test cavity 12. The battery cell to be tested 2 only conducts force between the pressure member 51 and the substrate 52. The pressure applied by the pressure member 51 is transmitted along the relative setting direction and is equal. The pressure sensor can be set in the substrate 52 or on the two side surfaces of the substrate 52 along the relative setting direction. The value of the pressure sensor can directly reflect the pressure value applied by the pressure member 51 to the battery cell to be tested 2 when it is fixed.

[0042] After the pressure sensor is pressurized and outputs a pressure value in real time, it is used to feed back the real-time output pressure value to the pressure-applying member 51 through a programmable logic controller (PLC). The pressure-applying member 51 adjusts the pressure output to the test probe 4 and the battery cell 2 to be tested through the feedback signal until the pressure applied to the battery cell 2 to be tested for fixing reaches a second preset pressure. The specific value of the second preset pressure can be set according to the size and other characteristics of the battery cell 2 to be tested. In some embodiments, the second preset pressure can be set to 5N~10N. If the second preset pressure is too high, it is easy to crush the tab 2201, causing damage to the tab or expansion of the battery cell. If the second preset pressure is too low, the fixing effect is poor and it is easy to cause the battery cell to tilt and fall.

[0043] Specifically, in a preferred embodiment of the first embodiment of the present invention, the cell to be tested 2 is configured as a cylindrical wound cell. The top and bottom surfaces of the cylinder serve as the two end surfaces 22 of the cell to be tested 2 for extending the tabs 2201 . The side surfaces of the cylinder, i.e., the test surface 21 of the cell to be tested 2 exposed within the test cavity 12 , are curved.

[0044] Corresponding to the cylindrical wound cell, when the cell to be tested 2 is placed and fixed in a vertical direction, the central axis of the cylindrical structure extends in the vertical direction. In addition to the technical effects of facilitating assembly and pressure fixation as mentioned above, this placement orientation can also reduce the risk of collapse of the cylindrical cell.

[0045] The cylindrical structural design provides the battery cell with high axial compressive strength. When placed upright, the cell's own weight is transferred axially, providing good load-bearing capacity. When placed horizontally or tilted, although the test surface 21 can also be evenly stressed, the direction of the cell's weight is not parallel to the direction of pressure applied by the pressure member 51. The cell is subjected to non-axial forces, making it more susceptible to deformation, collapse, and rupture due to stress concentration, affecting test safety.

[0046] Specifically, refer to Figure 2 As shown, the cylindrical wound cell has a winding hole along its central axis. A support member 6 is also provided in the winding hole of the cell to be tested 2. The support member 6 is made of a smooth and hard material. The support member 6 extends through the winding hole along the central axis, with both ends of the support member 6 extending beyond the end face 22 of the cell to be tested 2. The support member 6 provides central support to prevent the internal structure of the cell to be tested 2 from collapsing if subjected to external forces.

[0047] The first end 61 of the support member 6 is disposed on the substrate 52, and one of the test probes 4 is disposed on the substrate 52 and penetrated by the support member 6. The support member 6 can be pre-fixed to the substrate 52 via the first end 61, and then inserted into the substrate 52 when the battery cell 2 to be tested is placed into the test cavity 12. Alternatively, the support member 6 can be pre-inserted into the winding hole and then placed into the test cavity 12 together with the battery cell 2 to be tested and fixed to the substrate 52.

[0048] The second end 62 of the support member 6 is mounted within the avoidance hole 5101 of the pressure member 51. Another of the test probes 4 is disposed on the pressure member 51 and is penetrated by the support member 6. The second end 62 of the support member 6 is configured as a cone, the tip of which has a relatively small radial dimension, thereby improving the alignment accuracy of the support member 6 during insertion. The tip of the cone is configured as a curved surface to prevent damage to the battery cell 2 to be tested during insertion. And / or, the extension length D2 of the second end 62 of the support member 6 beyond the test probe 4 is greater than or equal to 5 mm.

[0049] Exemplarily, the second end 62 of the support member 6 extends by 30 mm beyond the end face 22 of the battery cell to be tested, and the thickness of the test probe 4 abutting the end face 22 is 20 mm, then the extension length D2 of the second end 62 of the support member 6 extending beyond the test probe 4 is 10 mm.

[0050] The pressure member 51 is provided with an avoidance hole 5101 at the position where the support member 6 is located, for accommodating its second end 62. The avoidance hole 5101 is set as a blind hole to prevent the through-hole structure from damaging the airtightness of the test chamber 12. The pressure member 51 abuts the test probe 4 to apply pressure to the end face 22 of the battery cell 2 to be tested. The thickness direction of the test probe 4 is the same as the direction in which the two end faces 22 of the battery cell 2 to be tested are relatively arranged. The pressure member 51 abuts the surface of the test probe 4 away from the battery cell 2 to be tested in the thickness direction. Therefore, the extension length D2 of the part of the second end 62 of the support member 6 that exceeds the test probe 4 needs to be adapted to the depth D1 of the avoidance hole 5101, and D2≤D1 exists. If the extension length of the part of the second end 62 of the support member 6 that exceeds the test probe 4 is too short, it is inconvenient to accurately align the battery cell 2 to be tested, and the support and fixing effect is also not ideal. If the extension length is too long, the corresponding avoidance hole 5101 depth required is larger, which is inconvenient to assemble the pressure member 51.

[0051] Specifically, the test circuit includes a test probe 4 and a detection component. The two end faces 22 of the battery cell 2 to be tested extend to tabs 2201 of different polarities. The end faces 22 of the battery cell 2 to be tested, where the tabs 2201 extend, abut against the test probe 4 of the corresponding polarity, electrically connecting the tabs 2201 to the test probe 4.

[0052] The test unit includes wires, a power supply, a protective resistor, a switch, and measuring instruments such as an ammeter and / or a voltmeter. Connected to two test probes (4) of different polarity, the test unit forms a complete electrical circuit, providing the necessary electrical connections and measurement capabilities for cell short-circuit testing. Voltage or current is applied, and abnormal readings from the measuring instruments determine whether the cell has a short circuit.

[0053] In the first embodiment of the present invention, the test probe 4 is configured as a pancake-shaped probe, which can better contact the tab 2201 than needle-shaped or fork-shaped probes. The cross-sectional shape of the pancake-shaped probe can be configured as a circle corresponding to the cylindrical battery cell 2 to be tested, or can be configured as a square, oval, or other special shape. The cross-sectional shape here refers to the cross-sectional shape of the pancake-shaped probe perpendicular to its thickness direction.

[0054] When the pancake-shaped probe is electrically connected to the battery cell 2 to be tested, it fully covers the end face 22 of the battery cell to avoid missed detection areas. The orthographic projection of the end face 22 of the cylindrical battery cell along the central axis direction falls inside the orthographic projection of the pancake-shaped probe in the same direction. The edge of the test probe 4 exceeds the periphery of the end face 22 of the battery cell 2 to be tested where it contacts the test probe 4. It is preferred that the cross section of the test probe 4 is set to a regular circle and is concentric with the end face 22 of the battery cell to be tested. The diameter of the cross section is larger than the diameter of the end face 22 and the diameter difference is at least 3 mm, that is, Figure 3 The radial difference D3 is ≥1.5 mm, which can ensure that the test probe 4 is fully connected to the battery cell 2 to be tested, and no missed detection area will occur even if the battery cell is slightly displaced.

[0055] Specifically, refer to Figure 1 As shown, the gas control assembly 3 includes a vacuum line 31, a gas input line 32, and a gas recovery line 33. The vacuum line 31 is in communication with the test chamber 12 and is used to evacuate the test chamber 12. The gas input line 32 is in communication with the test chamber 12 and is used to input a gaseous medium into the test chamber 12. The gas recovery line 33 is in communication with the test chamber 12 and is used to extract gas from the test chamber 12.

[0056] Furthermore, the density of the gas medium introduced during the short-circuit test of the battery cell is consistent at all locations. The gas medium can be set to an inert gas such as nitrogen or clean air. The flow characteristics of the same gas or gas medium with the same density are consistent, and thus the pressure applied to the test surface 21 is consistent, meeting the requirement of uniform pressurization during the short-circuit test. In addition, the gas medium can also be set to a mixed gas. When set to a mixed gas, the ratio of the mixed gas needs to be adjusted to avoid gas stratification. The stratified mixed gas may cause uneven pressure on the test surface 21.

[0057] A pressure sensor 7 is also provided in the test chamber 12, and the pressure sensor 7 is used to feed back the gas pressure in the test chamber 12 to the gas control component 3. This allows the gas control component 3 to evacuate or inflate the test chamber 12 until the gas pressure in the test chamber 12 reaches a first preset pressure. The first preset pressure is determined based on the actual needs of the battery cell short-circuit test. The larger the value of the first preset pressure, the greater the risk of deformation, rupture, and internal short circuit of the battery cell. Exceeding the normal operating range may cause distortion of the test results and interfere with the evaluation. The smaller the value of the first preset pressure, the smaller the risk of deformation and short circuit of the battery cell. If it is lower than the normal range, it may result in the inability to expose the defects of the battery cell, and there are certain hidden dangers in concealing safety issues.

[0058] The battery cell short-circuit test device provided in the first embodiment of the present invention can uniformly pressurize the test surface 21 of the non-planar structure of the battery cell 2 to be tested, so that the internal positive and negative electrodes and the diaphragm of the battery cell 2 to be tested are in full contact, and defects such as molten beads and foreign particles break through the diaphragm under the high voltage of the short-circuit test to cause a short circuit, thereby achieving the purpose of screening short-circuited batteries. Compared with mechanical pressurization and other methods, it not only solves the problem that non-planar surfaces are difficult to pressurize, but also can complete the test without destroying the battery cell structure, avoiding damage to the battery cell caused by physical contact. In addition, the rapid response and uniform distribution characteristics of the gas pressure can also effectively improve the test efficiency and accuracy, and reduce test errors.

[0059] Reference Figure 4 As shown, the second embodiment of the present invention further provides a cell short circuit test method. The cell short circuit test method can be implemented based on the cell short circuit test device in the first embodiment. Specifically, the cell short circuit test method includes the following steps: In step S100 , the battery cell 2 to be tested is placed in the sealed test cavity 12 of the device body 1 , and the test surface 21 of the battery cell 2 to be tested is exposed in the test cavity 12 .

[0060] As an implementable method, step S100 includes: In step S110, opening 11 of apparatus body 1 is opened, and the cell to be tested 2 is placed on substrate 52 within apparatus body 1. The end face 22 of the positive electrode tab of the cell to be tested 2 abuts against the positive electrode test probe 4 on substrate 52 to establish an electrical connection. A support member 6 extends through the winding hole of the cell to be tested 2 to provide support, and a first end 61 of the support member 6 is connected to substrate 52.

[0061] In step S120, the avoidance hole 5101 of the pressure member 51 is aligned with the second end 62 of the support member 6 extending beyond the battery cell 2 to be tested, and the pressure member 51 is sealedly connected to the opening 11 as a sealing cover, and the device body 1 is closed to form a closed space in the test cavity 12. At this time, the test surface 21 of the battery cell 2 to be tested, except for the two end faces 22, is exposed in the test cavity 12.

[0062] In step S130, the pressure member 51 is adjusted so that it applies pressure toward the substrate 52 along the axis of the battery cell 2 to be tested. The pressure member 51 and the negative electrode test probe 4 are moved synchronously until they abut against the end surface 22 of the negative electrode tab of the battery cell 2 to be tested, thereby establishing an electrical connection between the negative electrode test probe 4 and the battery cell 2 to be tested.

[0063] In step S140, the pressure sensor on the substrate 52 feeds back pressure to the pressure member 51 through the PLC, and then adjusts the force applied to the battery cell 2 to be tested by the position of the pressure member 51 until the pressure applied by the pressure member 51 is controlled to be the second preset pressure and the adjustment of the pressure member 51 is stopped.

[0064] In step S200 , measuring instruments and other electrical components in the test circuit except the test probe 4 are electrically connected to the battery cell 2 to be tested via the test probe 4 to form a complete circuit.

[0065] In step S300, the gas control component 3 is used to fill the test chamber 12 with a gas medium so that the pressure in the test chamber 12 reaches a first preset pressure. The gas medium is set to be an inert gas or pure air.

[0066] Specifically, before filling the test chamber 12 with the gaseous medium, the air within the test chamber 12 must be evacuated via the vacuum line 31. The vacuum line 31 is then closed, and the gaseous medium, preferably nitrogen, is continuously introduced into the test chamber 12 via the gas inlet line 32. According to Pascal's law, the pressure of the gaseous medium within the test chamber 12 is uniformly transmitted in all directions. By continuously pressurizing and filling with nitrogen, the force applied to the test surface 21 is uniform.

[0067] The pressure sensor 7 in the test chamber 12 provides real-time feedback of the pressure in the chamber. When the pressure in the test chamber 12 reaches a first preset pressure, nitrogen filling is stopped. The gas input pipe 32 is closed to maintain the airtightness of the test chamber 12.

[0068] In step S400 , after the gas state in the test chamber 12 is stabilized, the voltage or current of the test cell 2 is detected by the test circuit, and whether the test cell 2 is short-circuited is determined based on the abnormal performance of the test circuit.

[0069] If an abnormally high current far exceeding the normal operating current of the battery cell appears in the test circuit, and / or the terminal voltage of the battery cell 2 to be tested drops sharply to near zero, a short circuit may have occurred. A data acquisition device that records the current and voltage waveforms in real time can also be set up in the test circuit. If the current curve instantly soars to a peak and remains high, and the voltage curve quickly drops below the threshold, it is determined that the battery cell 2 to be tested has a short circuit. In addition, a comprehensive judgment can be made by combining multi-dimensional data such as temperature performance and internal gas production detection of the battery cell.

[0070] In step S500, after the short circuit test is completed, the gas medium in the test chamber 12 is released, or the gas medium in the test chamber 12 is recovered through the gas recovery pipe 33 of the gas control assembly 3. The gas recovery pipe 33 can also be connected to an external purifier 34 to purify the gas medium for recycling.

[0071] When the gas pressure in the test cavity 12 is balanced with the atmospheric pressure, the opening 11 of the device body 1 is opened, and the battery cell 2 to be tested is taken out of the test cavity 12 .

[0072] The cell short circuit test method provided in the second embodiment of the present invention is implemented based on the cell short circuit test device of the first embodiment. Therefore, the method in the second embodiment includes all the technical effects of the device, which have been described in detail above and will not be repeated here.

[0073] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0074] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0075] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery short circuit test device, characterized in that: include: A device body (1), wherein the device body (1) is provided with an openable and closable opening (11), and when the opening (11) is closed, a sealed test cavity (12) is formed inside the device body (1) for accommodating a battery cell (2) to be tested; a test surface (21) of the battery cell (2) to be tested is exposed in the test cavity (12), wherein the test surface (21) is non-planar; A gas control component (3), the gas control component (3) controls the gas pressure in the test chamber (12); A test circuit, comprising a test probe (4), wherein the test probe (4) is electrically connected to the battery cell (2) to be tested.

2. The battery short circuit test device according to claim 1, characterized in that: Also included is a fixing assembly (5); The battery cell to be tested (2) comprises two end faces (22) arranged opposite to each other and extending from a tab (2201), and the test surface (21); the test surface (21) connects the two end faces (22); and the fixing assembly (5) fixes the battery cell to be tested (2) in the test cavity (12) along the direction in which the two end faces (22) are arranged opposite to each other.

3. The battery short circuit test device according to claim 2, characterized in that: The fixing assembly (5) comprises a pressure member (51) and a base plate (52); One end surface (22) of the battery cell to be tested (2) is arranged on the substrate (52) through the test probe (4), and the other end surface (22) contacts the pressure member (51) through the test probe (4); A pressure sensor is also provided on the substrate (52), and the pressure sensor is used to feed back the pressure exerted on the battery cell (2) to be tested to the pressure-applying member (51).

4. The battery short circuit test device according to claim 3, characterized in that: The pressure-applying member (51) is a sealing cover of the opening (11), and the sealing cover is sealedly connected to the opening (11).

5. The battery short circuit test device according to claim 3, characterized in that: The battery cell (2) to be tested is a cylindrical wound battery cell, and a support member (6) is further provided in the winding hole of the battery cell (2) to be tested, with both ends of the support member (6) extending beyond the end surface (22) of the battery cell (2) to be tested; The first end (61) of the support member (6) is arranged on the base plate (52); the second end (62) is installed in the avoidance hole (5101) of the pressure member (51), and the avoidance hole (5101) is a blind hole.

6. The battery short circuit test device according to claim 5, characterized in that: The second end (62) of the support member (6) is configured as a cone, and the tip of the cone is configured as a curved surface; And / or, the extension length of the portion of the second end (62) of the support member (6) extending beyond the test probe (4) is greater than or equal to 5 mm.

7. The battery short circuit test device according to claim 1, characterized in that: The end surface (22) of the lead-out tab (2201) of the battery cell to be tested (2) abuts against the test probe (4) of corresponding polarity to electrically connect the tab (2201) and the test probe (4); the edge of the test probe (4) exceeds the periphery of the battery cell to be tested (2).

8. The battery short circuit test device according to claim 1, characterized in that: The gas control assembly (3) includes a vacuum pipe (31), a gas input pipe (32) and a gas recovery pipe (33); The vacuuming pipe (31) is in communication with the test chamber (12) and is used to vacuum the test chamber (12); The gas input pipe (32) is in communication with the test chamber (12) and is used to input a gas medium into the test chamber (12), wherein the density of the gas medium is uniform at all locations; The gas recovery pipe (33) is in communication with the test chamber (12) and is used to extract gas from the test chamber (12); A pressure sensor (7) is also provided in the test chamber (12), and the pressure sensor (7) is used to feed back the gas pressure in the test chamber (12) to the gas control component (3).

9. A method for testing a short circuit of a battery cell, characterized in that: The steps include: Placing the battery cell (2) to be tested in a sealed test cavity (12) of the device body (1), exposing the test surface (21) of the battery cell (2) to be tested in the test cavity (12); Electrically connecting the test circuit to the battery cell (2) to be tested; Filling the test chamber (12) with a gas medium through a gas control component (3) so that the gas pressure in the test chamber (12) reaches a first preset pressure; wherein the gas medium is set to be an inert gas or pure air; The voltage or current of the battery cell (2) to be tested is detected by a test circuit to determine whether the battery cell (2) to be tested is short-circuited.

10. The battery cell short circuit testing method according to claim 9, characterized in that: The battery cell (2) to be tested is placed in a sealed test cavity (12) of the device body (1), including: Opening the opening (11) of the device body (1), placing the battery cell (2) to be tested on the substrate (52) in the test cavity (12), and passing the support member (6) through the winding hole of the battery cell (2) to be tested; Align the avoidance hole (5101) of the pressure-applying member (51) with the second end (62) of the support member (6) extending beyond the battery cell (2) to be tested, seal the pressure-applying member (51) with the opening (11), and apply pressure in the direction of the substrate (52); The pressure sensor of the substrate (52) feeds back pressure to the pressure-applying member (51) until the pressure applied by the pressure-applying member (51) is controlled to be a second preset pressure.

11. The battery cell short circuit testing method according to claim 9, characterized in that: Before filling the test cavity (12) with gas medium via the gas control component (3), the method further comprises extracting the air in the test cavity (12) via the gas control component (3).

12. The battery cell short circuit testing method according to claim 9, characterized in that: After determining whether the battery cell (2) to be tested is short-circuited, the method further comprises: releasing the gaseous medium in the test chamber (12), or recovering the gaseous medium in the test chamber (12) through a gas control component (3); When the gas pressure in the test cavity (12) is balanced with the atmospheric pressure, the opening (11) of the device body (1) is opened, and the battery cell (2) to be tested is removed from the test cavity (12).

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