Cylindrical cell voltage and internal resistance testing device

Abstract

The utility model discloses a voltage and internal resistance testing device for a cylindrical cell. The voltage and internal resistance testing device comprises a four-wire method wiring assembly, a width limiting assembly, a length limiting assembly and a clamping force control assembly. The four-wire-method wiring assembly comprises two current wires and two voltage wires, alternating current is injected into the cylindrical battery cell through a four-wire wiring method, voltage drop signals are collected, interference of contact resistance and wire resistance is eliminated, and the testing precision is improved; the width limiting assembly and the length limiting assembly can realize free adjustment of the limiting height and the test length, and are suitable for cylindrical battery cells of different specifications; the clamping force control assembly is fixed to one side of the length limiting assembly, and constant clamping force is applied and maintained to ensure stable testing. According to the device, test positions are consistent through the movable limiting structure, the device is compatible with multi-size cylindrical battery cells, and the device has the characteristics of high test precision, wide application range and convenience in operation by combining the design of constant clamping force.

Description

Technical Field

[0001] This utility model relates to the field of testing technology, and in particular to a device for testing the internal resistance of a cylindrical battery cell. Background Technology

[0002] Existing cylindrical battery cell voltage and internal resistance testing devices mostly employ a two-wire parallel connection method, where the current and voltage lines share a common circuit. This leads to mutual interference between the wiring resistance and lead resistance and the actual impedance of the cylindrical battery cell, resulting in measurement errors exceeding the milliohm level, making it difficult to meet high-precision testing requirements. Furthermore, the fixed test slot structure only accommodates cylinders of specific sizes, exhibiting poor versatility. The clamping mechanism relies on mechanical baffles for support, which, after prolonged use, leads to unstable clamping force due to mechanical fatigue (e.g., relying solely on baffle compression without constant pressure control). Additionally, the V-shaped metal slot is prone to surface damage from impacts, affecting test reliability. Repeated manual adjustment of the baffle spacing is required during loading and unloading, resulting in cumbersome and inefficient operation. These shortcomings limit the measurement accuracy, dimensional adaptability, clamping stability, and ease of use of the testing device.

[0003] There is an urgent need for an improved technical solution that offers high testing accuracy, multi-size compatibility, controllable clamping force, and efficient operation. Utility Model Content

[0004] This utility model addresses the problems of low testing accuracy due to interference from contact resistance and conductor resistance caused by the use of two-wire parallel connection in existing cylindrical battery cell voltage internal resistance testing devices; poor versatility due to the fixed test slot structure that only adapts to specific sizes; and unstable clamping force due to mechanical fatigue caused by the reliance on mechanical baffle support in the clamping mechanism. This invention provides a cylindrical battery cell voltage internal resistance testing device that uses a four-wire connection assembly to eliminate resistance interference and improve accuracy. Adjustable width and length limiting components adapt to cylindrical battery cells of different specifications, achieving multi-size compatibility. A clamping force control component (spring and clamp working together) applies and maintains a constant clamping force to ensure stable testing. Therefore, this device achieves high testing accuracy, multi-size compatibility, controllable clamping force, and efficient operation. The technical solution provided by this application is as follows:

[0005] This application provides a device for testing the internal resistance of a cylindrical battery cell, comprising:

[0006] The four-wire connection assembly includes two current wires and two voltage wires. The two current wires are connected to the current probe via copper lugs and are used to inject AC current into the cylindrical cell under test. The two voltage wires are soldered to the voltage probe and are used to collect the voltage drop signal generated at both ends of the cylindrical cell under test due to the AC current.

[0007] A width limiting component is set on the base and moves along the horizontal and vertical directions of the base to adapt to cylindrical cells of different diameters.

[0008] The length limiting component is symmetrically arranged on both sides of the width limiting component and moves horizontally along the base to adapt to cylindrical cells of different lengths.

[0009] A clamping force control component is fixedly disposed on the outside of one of the length limiting components, and is used to apply and maintain a constant clamping force on the cylindrical cell under test.

[0010] In some specific embodiments, the width limiting component includes a plurality of support baffles spaced apart along the horizontal direction of the base, each support baffle is provided with a limiting block, the limiting block is connected to the support baffle by a plurality of bolts, and the height can be adjusted in the vertical direction.

[0011] In some specific embodiments, the limiting block has an arc-shaped groove at one end facing the cylindrical battery cell to be tested.

[0012] In some specific embodiments, the length limiting component includes a movable baffle and a support member. The support member is disposed on the movable baffle and a spring is provided at one end facing the cylindrical cell to be tested. The spring cooperates with the clamping force control component to prevent the clamping force of the movable baffle from changing due to mechanical fatigue.

[0013] In some specific embodiments, the clamping force control component includes a clamp fixedly connected to an adjacent movable baffle for applying and maintaining a constant clamping force on the movable baffle.

[0014] In some specific embodiments, the movable baffle toward the clamping force control component includes a first baffle and a second baffle; the first baffle is connected to the support member and is used to define the axial reference of the cylindrical cell under test; the second baffle is connected to the clamping force control component and is used to transmit a constant clamping force to the end face of the cylindrical cell under test during clamping.

[0015] In some specific embodiments, the first baffle and the second baffle are fixedly connected as one unit by a horizontal baffle, which moves along the horizontal direction of the base.

[0016] In some specific embodiments, the movable baffle facing the clamping force control component has a U-shaped structure, and the movable baffle away from the clamping force control component has an L-shaped structure.

[0017] In some specific implementations, the two current lines and the two voltage lines are laid out separately, and the two voltage lines are soldered to the voltage probe by a soldering iron.

[0018] In some specific embodiments, the top surface of the base is provided with a slot, and both the support baffle and the movable baffle slide with the base through the slot, and move horizontally and lock along the direction of the slot.

[0019] By adopting the above technical solution, the cylindrical battery cell voltage internal resistance testing device provided in this application has the following beneficial effects:

[0020] The cylindrical battery cell voltage internal resistance testing device disclosed in this utility model has significant advantages in terms of testing accuracy, applicable range, ease of operation, and safety through the coordinated operation of a four-wire wiring design, an adjustable limiting structure, and a constant clamping force control component. The specific advantages are as follows:

[0021] 1. This device employs the four-wire method (Kelvin measurement method). Two independent current wires inject alternating current to form a closed loop, while the other two voltage wires are used only to detect the voltage drop across the terminals caused by the alternating current. The voltage wires do not carry current, completely avoiding the influence of lead resistance. This design separates the current loop from the voltage detection loop, effectively eliminating interference from contact resistance and wire resistance. It can control measurement errors to the milliohm or even microohm level, improving the accuracy and reliability of voltage internal resistance test data.

[0022] 2. This device achieves free adjustment of the limiting height and test length through the coordinated operation of the width limiting component and the length limiting component. The limiting position can be flexibly adjusted according to the actual diameter, length and other parameters of the cylindrical cell under test, ensuring that cylindrical cells of different specifications can be accurately positioned in the test area, and that the test positions of each cylindrical cell remain at a consistent height, avoiding fluctuations in test results caused by positioning deviations.

[0023] 3. This device innovatively employs a clamping force control component that combines a spring and a fixture. By applying and maintaining a constant clamping force through the fixture, it ensures a stable and fixed state throughout the testing process. Furthermore, the spring structure buffers mechanical stress, effectively solving the problem of clamping force failure caused by mechanical fatigue. Simultaneously, the consistent operation of the fixture ensures that the clamping force is the same for each test, further improving the repeatability and reliability of the test results. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the cylindrical cell voltage internal resistance testing device provided in the embodiments of this application in the clamped state;

[0026] Figure 2 This is a schematic diagram of the cylindrical cell voltage internal resistance testing device provided in the embodiment of this application in its unfolded state.

[0027] The following is supplementary explanation of the attached figures:

[0028] 1-Width limiting component; 11-Support baffle; 12-Limiting block; 13-Copper lug; 14-Voltage probe;

[0029] 2-Length limiting component; 21-Moving baffle; 22-Support component;

[0030] 3-Clamping force control assembly; 31-Clamp;

[0031] 4-Spring;

[0032] 5-Base; 51-Slot. Detailed Implementation

[0033] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0034] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0035] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0036] Please see Figure 1 and Figure 2 This application provides a cylindrical battery cell voltage internal resistance testing device, comprising:

[0037] The four-wire connection assembly includes two current wires and two voltage wires. The two current wires are connected to the current probes via copper lugs 13 to inject AC current into the cylindrical cell under test. The two voltage wires are soldered to the voltage probes 14 to collect the voltage drop signal generated at both ends of the cylindrical cell under test due to the AC current.

[0038] Specifically, the two current lines and two voltage lines are designed to be laid out separately. The two current lines are connected to the device through copper lugs 13 and connected to the current probes. The copper lugs 13 are mechanically fastened with screws to ensure low impedance transmission of the high current path. The two voltage lines are precisely soldered to the voltage probes 14 with a soldering iron to form a stable electrical connection point, enabling high-precision acquisition of voltage signals. Through physical separation and differentiated connection technology, the current line circuit carrying high current and the voltage line detection circuit that only detects small voltage drops are completely independent, fundamentally eliminating the mutual interference problem of wiring resistance and lead resistance in the traditional two-wire parallel connection method.

[0039] Width limiting component 1 is set on base 5 and moves along the horizontal and vertical directions of base 5 to adapt to cylindrical cells of different diameters; specifically, it includes a support baffle 11 and a limiting block 12. The limiting block 12 is fixed on the support baffle 11 and the height position of the limiting block 12 is adjusted by four bolts, thereby accurately controlling the limiting height and ensuring that the device can adapt to and stably test cylindrical cells of different diameters.

[0040] The length limiting component 2 is symmetrically arranged on both sides of the width limiting component 1 and moves horizontally along the base 5 to adapt to cylindrical cells of different lengths. Specifically, the length limiting component 2 includes two sets, which are symmetrically arranged on both sides of the width limiting component 1. Both sets of components can move synchronously or independently along the horizontal direction of the base 5. By adjusting their relative positions with the width limiting component 1, they can accurately adapt to cylindrical cells of different lengths.

[0041] Both the width limiting component 1 and the length limiting component 2 use high-strength engineering plastic (such as ABS, PC, or modified PP) structural parts as limiting devices. The contact end faces are rounded and coated with an anti-slip and wear-resistant coating to avoid the damage caused by direct rigid contact between traditional metal limiting structures (such as V-shaped metal slots 51) and the cylindrical battery cell surface. The plastic material itself has low hardness and excellent elastic modulus. When the cylindrical battery cell is installed in the limiting area, the plastic limiting device buffers the impact force during the assembly process through flexible contact, reducing the risk of the cylindrical battery cell shell (especially aluminum or steel shell) being scratched, dented, or cracked. It guides the cylindrical battery cell to slide smoothly into the predetermined position and avoids the concentrated stress effect of sharp corners on the surface. At the same time, the surface resistivity of engineering plastic is moderate and it is not easy to generate static electricity accumulation, further reducing the risk of adsorption damage or charge accumulation on the coating of the cylindrical battery cell surface.

[0042] The clamping force control component 3 is fixedly installed on the outside of one of the length limiting components 2, and is used to apply and maintain a constant clamping force on the cylindrical cell under test.

[0043] Specifically, the clamping force control component 3 includes a clamp 31, which, in cooperation with the spring 4, can stably maintain a consistent clamping force each time. At the same time, the buffering effect of the spring 4 can effectively offset the mechanical fatigue caused by long-term use between the baffles, ensuring the continuous reliability of the clamping force and the stability of the testing process. If the clamping contact becomes loose, it essentially means that an additional contact resistance is formed between the probe and the cylindrical cell terminal. This contact resistance directly interferes with the sampling calculation of the tester, causing the voltage and internal resistance measurement results to deviate significantly from the true values. On the one hand, during voltage measurement, the contact resistance and internal resistance are connected in series to form a voltage divider effect. According to Ohm's law, the voltage actually collected by the tester is the true voltage minus the voltage divided by the contact resistance, resulting in a lower or unstable measurement result (e.g., for lithium with a true voltage of 3.7V, the voltage may fluctuate repeatedly between 3.5V and 3.65V due to contact resistance fluctuations). On the other hand, during internal resistance measurement, the internal resistance tester calculates the internal resistance by injecting a small current and measuring the ratio of current to voltage drop (R=U / I). The contact resistance is directly superimposed on the true internal resistance, and the tester cannot distinguish between the two, misjudging the sum of the contact resistance and internal resistance as the internal resistance, resulting in a significantly higher measurement result (e.g., if the true internal resistance is 50mΩ, but the contact resistance is 100mΩ, the measurement result will show 150mΩ). This error is the most critical test deviation point. Through precise mechanical control and elastic compensation mechanisms, the problem of inconsistent clamping force caused by mechanical fatigue in traditional clamping devices is effectively solved, ensuring stable and reliable electrical contact between the probe and the electrode. This fundamentally eliminates the interference of additional contact resistance on the test results, improves the accuracy, repeatability and reliability of voltage and internal resistance tests, and provides a solid mechanical and electrical guarantee for the accurate testing of cylindrical cells.

[0044] In some specific embodiments, the width limiting component 1 includes a plurality of support baffles 11 spaced apart along the horizontal direction of the base 5. Each support baffle 11 is provided with a limiting block 12. The limiting block 12 is connected to the support baffle 11 by a plurality of bolts and can be adjusted in the vertical direction. Preferably, there are four bolts and the height can be adjusted in the vertical direction to adapt to cylindrical cells of different diameters.

[0045] In some specific embodiments, the limiting block 12 has an arc-shaped groove at one end facing the cylindrical cell to be tested. Specifically, the limiting block 12 has an arc-shaped groove at one end facing the cylindrical cell to be tested that matches the outer contour of the cylindrical cell. This groove structure is designed based on the standard diameter of the cylindrical cell, and forms a line contact support with the surface of the cylindrical cell through a precise curved surface; it increases the contact area between the support baffle 11 and the cylindrical cell, disperses local stress concentration during the clamping process, and effectively avoids damage or deformation of the cylindrical cell shell caused by rigid contact; in addition, the directional guiding effect of the arc-shaped groove can help the cylindrical cell to be quickly positioned to the preset test center, improving clamping efficiency and positional accuracy. At the same time, the smooth transition design of the inner wall of the groove further reduces the frictional loss of the coating on the surface of the cylindrical cell, taking into account both test stability and the protection requirements of the cylindrical cell body.

[0046] In some specific embodiments, the length limiting component 2 includes a movable baffle 21 and a support member 22. The support member 22 is disposed on the movable baffle 21, and a spring 4 is provided at one end facing the cylindrical battery cell to be tested. The spring 4 cooperates with the clamping force control component 3 to prevent changes in the clamping force of the movable baffle 21 due to mechanical fatigue. Specifically, the spring 4 is used in conjunction with the reinforced 301AM quick clamp 31 to ensure a stable clamping force of 45kg. Its core principle is to use the elastic characteristics of the spring 4 to compensate for variables in the mechanical system. When the clamp 31 is closed, the spring 4 is in a pre-compressed state and provides a pre-tightening force F. 预 When the clamp 31 shows signs of loosening due to mechanical clearance or long-term wear, the spring 4 further compresses or rebounds through its own elastic deformation (according to Hooke's Law F=k·Δx, where k is the spring constant of the spring 4 and Δx is the deformation), dynamically maintaining the clamping force on the workpiece and ensuring that the final clamping force acting on the cylindrical battery cell remains stable at 45kg; at the same time, this design works in conjunction with the lever principle of the clamp 31 (assuming the force applied by the handle is F). 手 The distance from the handle to the fulcrum is L1 (effort arm), and the distance from the push rod to the fulcrum is L2 (resistance arm). According to the lever balance F... 手 ·L1=F 杠 • L2, F is the force exerted by the lever on the push rod), which amplifies the operating force through the lever to generate a larger clamping force (F) 杠 ), and with the preload F of spring 4 预 Together they constitute the final clamping force F 夹 (F) 夹 =F 杠 +F 预 =441N, which is 45kg × 9.8N / kg), needs to be based on the known F 手 Accurate calculation of F for L1 and L2 杠 (F) 杠 =F 手 ·L1 / L2), and then by F预 =F 夹 -F 杠 The required preload of spring 4 is derived, and the spring constant and specifications of spring 4 are determined by combining Hooke's law and precompression amount, so as to achieve precise control of clamping force. In addition, spring 4 can also buffer the impact force at the moment the clamp 31 closes, reducing the impact of instantaneous force fluctuation on clamping stability. Through the above structural design, the problem of clamping force attenuation caused by fatigue of traditional mechanical baffles is effectively solved, ensuring consistent force in each test, improving test accuracy, and extending the service life of the device.

[0047] In some specific embodiments, the clamping force control component 3 includes a clamp 31, which is fixedly connected to an adjacent movable baffle 21 for applying and maintaining a constant clamping force on the movable baffle 21. Specifically, the clamp 31 and spring 4 cooperate in a coordinated manner. The main body of the clamp 31 is rigidly connected to the movable baffle 21 by fasteners and includes an operating handle and a push rod. The operating handle drives a lever mechanism to amplify the operating force, which is then transmitted to the movable baffle 21 via the push rod. At the same time, the spring 4 is pre-placed inside the clamp 31 to provide a basic preload. The two cooperate to form a stable clamping force transmission path; through the lever principle (the force F applied at the handle...), the clamping force is applied to the movable baffle 21. 手 The torque balance F between the effort arm L1 and the resistance arm L2 手 ×L1=F 杠 ×L2,F 杠 (To amplify the force acting on the push rod) the small force applied by the operator is converted into a large clamping force acting on the moving baffle 21, combined with the preload F of the spring 4. 预 Together they constitute the total clamping force F 夹 (F) 夹 =F 杠 +F 预 This ensures that the clamping force is stably maintained at the set value of 45kg (441N).

[0048] In some specific embodiments, the movable baffle 21 facing the clamping force control component 3 includes a first baffle and a second baffle; the first baffle is connected to the support member 22 and is used to define the axial reference of the cylindrical cell under test; the second baffle is connected to the clamping force control component 3 and is used to transmit a constant clamping force to the end face of the cylindrical cell under test during the clamping process.

[0049] Specifically, the first baffle has an arc-shaped positioning surface on its end face facing the cylindrical cell, which matches the outer diameter of the cylindrical cell. This surface is used to precisely define the axial reference position of the cylindrical cell under test, ensuring that the cylindrical cell is accurately centered along the axial direction during the test and preventing measurement errors caused by skewness. The second baffle is directly connected to the clamp 31. When the clamp 31 and the spring 4 apply a constant clamping force, the second baffle acts as a force transmission medium, uniformly applying a precisely controlled 45kg (441N) clamping force to the end face of the cylindrical cell under test, thus achieving stable axial clamping of the cylindrical cell. In other words, through the division of labor and cooperation between the reference positioning function of the first baffle and the force transmission function of the second baffle, both the axial positioning accuracy during the cylindrical cell test and the precise and controllable transmission of the clamping force are ensured.

[0050] In some specific embodiments, the first baffle and the second baffle are fixedly connected as a whole by a horizontal baffle, which moves horizontally along the base 5. Specifically, the first baffle and the second baffle are rigidly fixedly connected as a whole by a high-strength horizontal baffle. The bottom of the horizontal baffle is in sliding fit with the base 5 through a guide rail pair or a slider structure, so that the whole assembly consisting of the first baffle, the second baffle and the horizontal baffle can move precisely along the horizontal direction of the base 5. The horizontal baffle, as an intermediate medium for force transmission and position control, not only ensures that the relative position between the first baffle (axial reference positioning baffle) and the second baffle (clamping force transmission baffle) is fixed, maintaining the overall rigidity and coaxiality of the double baffle system, but also realizes the smooth translation of the whole assembly through the low friction characteristics of the guide rail pair.

[0051] In some specific embodiments, the movable baffle 21 facing the clamping force control component 3 has a U-shaped structure, while the movable baffle 21 facing away from the clamping force control component 3 has an L-shaped structure. Specifically, the U-shaped structure has an arc-shaped positioning surface that matches the outer diameter of the cylindrical battery cell, and integrates a support member 22 and a spring 4 buffer structure to accurately define the axial reference position of the cylindrical battery cell under test and uniformly transmit the clamping force; the L-shaped structure is composed of a vertical plate and a horizontal base plate. Its L-shaped bending design not only ensures a stable connection between the movable baffle 21 and the base 5, but also provides a precise installation reference for the first baffle (axial reference baffle) and the second baffle (clamping force transmission baffle) through the positioning surface of the vertical plate, ensuring the coaxiality and flatness of the two baffles.

[0052] In some specific implementations, the two current lines and the two voltage lines are laid out separately, and the two voltage lines are soldered to the voltage probe 14 by a soldering iron.

[0053] Specifically, the two current lines and two voltage lines are designed with separate routing. The two current lines are reliably connected to the current probe via copper lugs 13, which are mechanically secured with screws to ensure low impedance transmission of the high current path. The two voltage lines are precisely soldered to the voltage probe 14 using a soldering iron, forming a stable electrical connection point for high-precision voltage signal acquisition. Through physical separation and differentiated connection technology, the current line loop carrying high current and the voltage line detection loop that only detects small voltage drops are completely independent, fundamentally eliminating the mutual interference problem of wiring resistance and lead resistance in the traditional two-wire parallel connection method. The copper lug 13 connection method not only maximizes the contact area between the current line and the current probe, but also further reduces impedance with screw fastening. The contact resistance ensures stable transmission of large currents (AC test current) without significant voltage drop, while also providing excellent mechanical stability and vibration resistance. The precision welding process of the voltage lines ensures the continuity of the electrical connection between the voltage probe 14 and the voltage lines, as well as low impedance characteristics. The extremely small contact area of ​​the welding point avoids interference from lead resistance on minute voltage signals, making the voltage detection circuit completely unaffected by the current circuit. This achieves the core function of the four-wire method (Kelvin measurement method), completely separating the current circuit from the voltage detection circuit, and precisely controlling the measurement error to the milliohm or even microohm level. This significantly improves the accuracy, stability, and reliability of cylindrical cell voltage internal resistance testing, providing a solid electrical connection guarantee for obtaining test data that truly reflects the intrinsic characteristics of cylindrical cells.

[0054] In some specific embodiments, a slot 51 is provided on the top surface of the base 5. Both the support baffle 11 and the movable baffle 21 are slidably engaged with the base 5 through the slot 51, and can move horizontally and lock along the direction of the slot 51. Specifically, a precision-machined linear slot 51 is provided on the top surface of the base 5 in the horizontal direction. The bottom of both the support baffle 11 and the movable baffle 21 is provided with a sliding boss that matches the cross-sectional shape of the slot 51. The sliding engagement with the base 5 is achieved by the engagement of the boss with the slot 51, so that the support baffle 11 and the movable baffle 21 can move horizontally and lock in position precisely along the straight trajectory set by the slot 51. The linear slot 51 provides the baffle with a linear movement track with high guiding accuracy and low frictional resistance, ensuring that the support baffle 11 and the movable baffle 21 always maintain strict parallelism and coaxiality during position adjustment, avoiding positioning deviation caused by manual adjustment. The embedded engagement of the sliding boss with the slot 51 restricts the sliding engagement with the base 51. The design prevents the baffle from shifting vertically and ensures smooth movement through tight contact surfaces. Combined with screw fastening or quick-release locking mechanisms, the adjusted test spacing is effectively maintained, ensuring consistent axial positioning and clamping stability for cylindrical cells of different specifications during testing. Furthermore, the 51-slot sliding structure simplifies the installation and disassembly of the baffle, facilitating maintenance and component replacement. The standardized 51-slot layout provides a consistent reference for the coordinated adjustment of multi-baffle systems, enhancing the device's adaptability to cylindrical cells of different lengths and diameters, test repeatability, and ease of operation. This provides reliable mechanical positioning assurance for high-precision voltage resistance testing.

[0055] The above description is only an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for testing the internal resistance of a cylindrical battery cell, characterized in that, include: The four-wire connection assembly includes two current wires and two voltage wires. The two current wires are connected to the current probe through a copper lug (13) to inject AC current into the cylindrical cell under test. The two voltage wires are soldered to the voltage probe (14) to collect the voltage drop signal generated at both ends of the cylindrical cell under test due to the AC current. Width limiting component (1) is set on base (5) and moves along the horizontal and vertical directions of base (5) to adapt to cylindrical cells of different diameters; The length limiting component (2) is symmetrically arranged on both sides of the width limiting component (1) and moves horizontally along the base (5) to adapt to cylindrical cells of different lengths. The clamping force control component (3) is fixedly disposed on the outside of one of the length limiting components (2) for applying and maintaining a constant clamping force on the cylindrical cell to be tested.

2. The cylindrical battery cell voltage internal resistance testing device according to claim 1, characterized in that, The width limiting component (1) includes multiple support baffles (11) spaced apart along the horizontal direction of the base (5). Each support baffle (11) is provided with a limiting block (12). The limiting block (12) is connected to the support baffle (11) by multiple bolts and its height can be adjusted in the vertical direction.

3. The cylindrical battery cell voltage internal resistance testing device according to claim 2, characterized in that, The limiting block (12) has an arc-shaped groove at one end facing the cylindrical cell to be tested.

4. The cylindrical battery cell voltage internal resistance testing device according to claim 2, characterized in that, The length limiting component (2) includes a movable baffle (21) and a support member (22). The support member (22) is disposed on the movable baffle (21), and a spring (4) is provided at one end facing the cylindrical cell to be tested. The spring (4) cooperates with the clamping force control component (3) to prevent the clamping force of the movable baffle (21) from changing due to mechanical fatigue.

5. The cylindrical battery cell voltage internal resistance testing device according to claim 4, characterized in that, The clamping force control component (3) includes a clamp (31) which is fixedly connected to the adjacent movable baffle (21) for applying and maintaining a constant clamping force on the movable baffle (21).

6. The cylindrical battery cell voltage internal resistance testing device according to claim 4, characterized in that, The movable baffle (21) toward the clamping force control component (3) includes a first baffle and a second baffle; the first baffle is connected to the support member (22) and is used to define the axial reference of the cylindrical cell under test; the second baffle is connected to the clamping force control component (3) and is used to transmit a constant clamping force to the end face of the cylindrical cell under test during the clamping process.

7. The cylindrical battery cell voltage internal resistance testing device according to claim 6, characterized in that, The first baffle and the second baffle are fixedly connected as one unit by a horizontal baffle, and the horizontal baffle moves horizontally along the base (5).

8. The cylindrical battery cell voltage internal resistance testing device according to claim 4, characterized in that, The movable baffle (21) facing the clamping force control component (3) has a U-shaped structure, and the movable baffle (21) away from the clamping force control component (3) has an L-shaped structure.

9. The cylindrical battery cell voltage internal resistance testing device according to claim 1, characterized in that, The two current lines and the two voltage lines are laid out separately, and the two voltage lines are soldered to the voltage probe by a soldering iron.

10. The cylindrical cell voltage internal resistance testing device according to claim 4, characterized in that, The base (5) has a slot (51) on its top surface. The support baffle (11) and the movable baffle (21) are slidably engaged with the base (5) through the slot (51) and can move horizontally and lock along the direction of the slot (51).

Images