Battery swelling force testing device

Abstract

The utility model discloses battery expansion force testing arrangement, a battery expansion force testing arrangement, its characterized in that, including: clamp mechanism, spring mechanism, including second baffle, spring bottom plate and the elastic component connected between second baffle and spring bottom plate, spring bottom plate with clamp mechanism fixed connection, pressure adjusting mechanism, including top plate, first baffle, gear drive assembly and screw rod, gear drive assembly installs between first baffle and top plate, screw rod one end is connected with gear drive assembly, and the other end of screw rod is connected with second baffle, pressure sensor sets up between clamp mechanism with spring bottom plate, displacement sensor installs between clamp mechanism and penetrates spring bottom plate and second baffle, limit stop, detachably be located between second baffle and spring bottom plate, has realized the quick switching between two mainstream test modes of constant pressure measurement battery expansion thickness and constant displacement measurement battery expansion force.

Description

Technical Field

[0001] This utility model relates to the field of battery testing technology, and specifically to a battery expansion force testing device. Background Technology

[0002] The working process of a lithium-ion battery is essentially a process of lithium ions (Li+) repeatedly inserting and de-intercalating between the positive and negative electrodes. During charging, Li+ ions are extracted from the positive electrode lattice, migrate through the electrolyte, and insert into the negative electrode material; during discharging, the process is reversed. This lithium-ion "intercalation and de-intercalation" causes regular changes in the cell volume of the electrode material, directly manifested as the expansion and contraction of the battery electrode thickness. Furthermore, gas is generated during battery cycling, further causing battery expansion. Therefore, applying appropriate mechanical constraints to the cells in a power battery module is crucial; the magnitude of the constraint force directly affects the battery's performance, safety, and lifespan. Accurately measuring the expansion force and thickness changes of the battery under different operating conditions is of critical guiding significance for optimizing module design, selecting electrode materials, and evaluating battery systems.

[0003] Currently, some battery expansion force testing schemes exist in existing technologies, but all have certain limitations. For example, patent CN202110969349.6 discloses an improved testing device and method for monitoring the expansion force of lithium-ion pouch batteries. This device applies initial pressure to the battery through a pressure regulating mechanism and can monitor the changes in expansion force during charging and discharging under a fixed distance (constant displacement). However, this device cannot measure the change in battery thickness under constant pressure. In actual battery research and verification, simulating the free change of battery thickness under constant clamping force and simulating the accumulation of expansion force within a confined space (constant displacement) are two equally important and complementary testing scenarios. The single functionality of existing devices forces researchers to configure two different sets of tooling, resulting in high testing costs, low efficiency, and difficulty in comparing and analyzing data under the same benchmark. Utility Model Content

[0004] To address the technical problem that existing equipment cannot measure the change in expansion thickness under constant pressure, this invention proposes a battery expansion force testing device. Through a detachable limiting block, it enables rapid switching between two mainstream testing modes: measuring battery expansion thickness under constant pressure and measuring battery expansion force under constant displacement.

[0005] The technical solution adopted by this utility model is as follows: A battery expansion force testing device, comprising:

[0006] Fixture mechanism;

[0007] The spring mechanism includes a second baffle, a spring base plate, and an elastic component connecting the second baffle and the spring base plate, wherein the spring base plate is fixedly connected to the clamping mechanism.

[0008] A pressure regulating mechanism includes a top plate, a first baffle, a gear transmission assembly, and a screw. The gear transmission assembly is installed between the first baffle and the top plate. One end of the screw is connected to the gear transmission assembly, and the other end of the screw is connected to the second baffle.

[0009] A pressure sensor is disposed between the clamping mechanism and the spring base plate;

[0010] A displacement sensor is mounted on the clamping mechanism and passes through the spring base plate and the second baffle.

[0011] The limiting block is detachably located between the second baffle and the spring base plate.

[0012] Optionally, the clamping mechanism includes a third baffle, a first clamping plate, a second clamping plate, and a fourth baffle arranged sequentially from top to bottom. The third baffle is fixedly connected to the spring base plate, the first clamping plate is fixedly installed on the lower surface of the third baffle, and the second clamping plate is fixedly installed on the upper surface of the fourth baffle.

[0013] Optionally, the clamping mechanism further includes a tab clamping head assembly for clamping the battery tabs extending between the first clamping plate and the second clamping plate, the tab clamping head assembly being disposed on the side of the fourth baffle.

[0014] Optionally, the electrode clamp head assembly includes a clamp head base mounted on the side of the fourth baffle, a clamp head slide plate slidably disposed on the clamp head base, and an electrode clamp head mounted on the clamp head slide plate, wherein the electrode clamp head is provided with a voltage line plate and a current line plate.

[0015] Optionally, the gear transmission assembly includes a gear box, a large gear rotatably disposed within the gear box, and a small gear meshing with the large gear. The gear box is fixedly connected between the top plate and the first baffle. The large gear is coaxially connected to a drive shaft. The drive shaft passes upward through the top plate and is coaxially connected to a drive component. The small gear is connected to the screw.

[0016] Optionally, there are two pinions, which are symmetrically meshed on both sides of the large gear.

[0017] Optionally, it also includes a guide post, one end of which is fixedly connected to the first baffle, and the other end of which passes through the second baffle, the spring base plate, the third baffle and is fixedly connected to the fourth baffle.

[0018] Optionally, the pressure sensor is fixedly installed on the upper surface of the third baffle, and the pressure sensor is connected to an external data acquisition system.

[0019] Optionally, the housing of the displacement sensor is mounted on the upper surface of the third baffle, the probe of the displacement sensor passes upward through the spring base plate and the second baffle in sequence, and the displacement sensor is connected to an external data acquisition system.

[0020] The beneficial effects of this invention are as follows: Through the simple design of a detachable limiting block, it achieves rapid switching between two mainstream testing modes: constant pressure measurement of battery expansion thickness and constant displacement measurement of battery expansion force. This solves the problem of requiring two different sets of tooling or complex counterweight adjustments in existing technologies, greatly improving testing efficiency and reducing equipment purchase and maintenance costs. Furthermore, the pressure adjustment mechanism, combining gear transmission and a screw, allows for precise and effortless application of the preset initial pressure via rotating the drive component, and reliable locking at a designated position. Compared to traditional counterweight methods, this approach is more convenient to operate, provides more precise pressure settings, and offers better repeatability, avoiding uneven battery force caused by counterweight inertia or off-center loading. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure of the battery expansion force testing device with limit blocks according to an embodiment of this utility model;

[0022] Figure 2 This is a schematic diagram of the battery expansion force testing device proposed in this embodiment of the invention, with the limiting block removed.

[0023] The labels in the attached figures are as follows: 1. Second baffle; 2. Spring base plate; 3. Elastic component; 4. Screw; 5. Pressure sensor; 6. Displacement sensor; 7. Limiting block; 8. Third baffle; 9. First clamping plate; 10. Second clamping plate; 11. Fourth baffle; 12. Fixture head base; 13. Fixture head slide plate; 14. Pole clamping head; 15. Gear box; 16. Large gear; 17. Small gear; 18. Drive component; 19. Guide column; 20. First baffle; 21. Top plate. Detailed Implementation

[0024] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 and 2As shown in the figure, this embodiment discloses a battery expansion force testing device, mainly including a clamping mechanism, a spring mechanism, a pressure adjustment mechanism, a pressure sensor, and a displacement sensor. The clamping mechanism is used to hold a lithium battery and includes a third baffle, a first clamping plate, a second clamping plate, and a fourth baffle arranged sequentially from top to bottom. The third baffle is fixedly connected to the spring base plate of the spring mechanism. The first clamping plate is fixedly installed on the lower surface of the third baffle, and the second clamping plate is fixedly installed on the upper surface of the fourth baffle. The first and second clamping plates are rigid plates with highly flat surfaces, used to directly clamp the battery during testing, ensuring uniform force on the battery surface and avoiding uneven force affecting the insertion and extraction of lithium ions inside the battery, thus truly reflecting the battery performance.

[0026] The clamping mechanism further includes a tab clamping head assembly, which includes a clamping head base, a clamping head slide slidably disposed on the clamping head base, and a tab clamping head mounted on the clamping head slide. The tab clamping head is provided with a voltage line plate and a current line plate for connecting to external charging and discharging equipment. The tab clamping head is used to clamp battery tabs extending horizontally between the first clamping plate and the second clamping plate to achieve electrical connection. The clamping head base is fixedly mounted on the side of the fourth baffle, and the clamping head slide is slidably disposed on the clamping head base, allowing its position to be adjusted to accommodate different battery tab extension lengths. The tab clamping head assembly separates the electrical connection unit from the mechanical pressure unit, avoiding interference from wiring to pressure measurement and providing flexible tab adaptation capabilities.

[0027] The spring mechanism is located above the clamping mechanism and includes a second baffle, a spring base plate, and an elastic component connected between the second baffle and the spring base plate. The elastic component can be a spring. The spring base plate is fixedly connected to the third baffle of the clamping mechanism.

[0028] The pressure regulating mechanism, located above the spring mechanism, includes a gear transmission assembly and a screw driven by the gear transmission assembly. The gear transmission assembly includes a gearbox, a large gear rotatably disposed within the gearbox, and two small gears meshing with the large gear. The gearbox is fixed between a top plate and a first baffle, forming a stable, sealed transmission space. The large gear is rotatably disposed within the gearbox, and its inner circumferential wall is coaxially connected to a drive shaft. This drive shaft passes upward through the top plate and is coaxially connected to the output end of a drive unit located outside the gearbox. The drive unit can be a rotary handle or a rotary motor. The two small gears symmetrically mesh on both sides of the large gear, each with a screw connected below it. The screws pass downward through the first baffle, and their ends connect to the second baffle of the spring mechanism. The drive unit drives the gear set, ultimately converting it into linear motion of the screws, thereby precisely controlling the initial pressure applied to the battery and locking it at a designated position, making operation effortless and precise.

[0029] The pressure sensor is fixedly installed on the upper surface of the third baffle of the clamping mechanism and connected to an external data acquisition system. Located in the transmission chain and not in direct contact with the battery, it accurately reflects the overall stress on the battery while avoiding localized stress concentration caused by direct contact, thus ensuring the accuracy of the test data.

[0030] The housing of the displacement sensor is fixedly connected to the upper end face of the third baffle of the clamping mechanism. Its probe rod passes upward through the spring base plate and the second baffle in sequence and is connected to the external data acquisition system, so that the displacement sensor can directly and accurately measure the vertical displacement change of the third baffle caused by the expansion or contraction of the battery, thereby accurately reflecting the real-time change of the battery thickness.

[0031] The tooling is also equipped with a limit block, which is detachably disposed between the second baffle and the spring base plate.

[0032] The fixture's overall structure is aligned and guided by at least four vertically arranged guide posts. One end of each guide post is fixedly connected to the first baffle, and the other end passes sequentially through the second baffle, the spring base plate, and the third baffle, and is fixedly connected to the fourth baffle. When the pressure regulating mechanism drives the screw to move, the spring mechanism and the clamping mechanism move up and down along the guide posts. The guide posts prevent lateral displacement, ensuring the measurement accuracy of the pressure and displacement sensors. The first baffle, second baffle, spring base plate, and fourth baffle are fastened together with bolts, thus assembling a highly rigid overall frame to ensure structural stability during testing.

[0033] This battery expansion force testing device has two switchable testing modes, which are achieved by removing and installing the "limiting block":

[0034] Example 1 (Constant Pressure Measurement of Thickness Variation Mode)

[0035] Remove the limiting block between the second baffle and the spring base plate. At this point, the second baffle and the spring base plate are connected only by an elastic component. When the battery expands during charging and discharging, it pushes upwards against the clamping mechanism and the spring base plate. Since the second baffle is controlled by the pressure regulating mechanism, the upward movement of the spring base plate compresses the elastic component. According to Hooke's Law, within the elastic range, the pressure provided by the elastic component remains essentially constant. The work done by the battery expansion force is converted into the potential energy of the elastic component, thus maintaining the pressure on the battery at a constant value with slight fluctuations. During this process, a displacement sensor monitors in real time the decrease in distance between the spring base plate and the second baffle; this value represents the battery's expansion thickness.

[0036] The specific operating procedure is as follows: Place the battery expansion force testing device in the environmental chamber, remove the limiting block to allow the elastic component to extend and retract freely; rotate the rotary wrench counterclockwise to raise the pressure adjustment mechanism and spring mechanism through gear transmission and screw, ensuring that the gap between the first and second clamping plates is sufficient to install the battery cell to be tested; place the battery cell between the first and second clamping plates, allowing its tabs to extend from the side, slide the slide plate on the tab clamp head to adjust its position, and use the tab clamp head to clamp the battery tabs; rotate the rotary wrench clockwise downwards to bring the first clamping plate into contact with the battery cell, and continue rotating slowly to press the spring downwards through gear transmission and screw. The mechanism applies an external force to the battery cell until the pressure signal transmitted by the pressure sensor equals the predetermined initial pressure value; connects the positive and negative current lines and voltage lines of the charging and discharging equipment to the current line board and voltage line board of the electrode clamp head; closes the environmental chamber and sets the test temperature; turns on the charging and discharging equipment to perform the charging and discharging test; finally, the charging and discharging parameters, pressure, and displacement sensor data are monitored synchronously on the computer integrated software. The real-time recorded displacement sensor value is the change in the thickness of the battery cell under constant pressure. The pressure is automatically maintained constant by the elastic component, without the need for manual adjustment of the counterweight. The operation is simple and the data is continuous and accurate.

[0037] Example 2 (Constant Displacement Measurement of Expansion Force Mode)

[0038] A limiting block is installed between the second baffle and the spring base plate. This limiting block rigidly connects the second baffle and the spring base plate, fixing their relative distance. When the battery expands, the entire spring mechanism is locked by the limiting block, preventing the battery thickness from increasing, thus maintaining a constant displacement. The battery's expansion force cannot be released through the compression elastic component and is directly transmitted to the pressure sensor via the spring base plate and the third baffle, causing the pressure sensor reading to increase. This increased pressure value is the expansion force generated by the battery.

[0039] The specific operating method is as follows: Place the battery expansion force testing device in the environmental chamber, install the limiting block at the designated position between the second baffle and the spring base plate to fix the distance; the subsequent steps (such as installing the battery cell, connecting the tabs, applying the initial pressure, connecting the charging and discharging equipment, and setting the ambient temperature) are the same as in Example 1; turn on the charging and discharging equipment to perform the charging and discharging test; monitor various data synchronously on the computer integrated software, and the real-time pressure value minus the initial pressure value is the expansion force generated by the battery cell itself when the thickness is limited (constant displacement).

[0040] This invention allows switching to this mode simply by installing a limiting block, achieving two uses from one device and significantly improving testing efficiency and equipment utilization.

[0041] It is understood that the specific embodiments described above are merely for explaining the relevant utility model and not for limiting the utility model. It should also be noted that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict with each other. All equivalent structural transformations made based on the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly included within the protection scope of this utility model.

Claims

1. A battery expansion force testing device, characterized in that, include: Fixture mechanism; The spring mechanism includes a second baffle, a spring base plate, and an elastic component connecting the second baffle and the spring base plate, wherein the spring base plate is fixedly connected to the clamping mechanism. A pressure regulating mechanism includes a top plate, a first baffle, a gear transmission assembly, and a screw. The gear transmission assembly is installed between the first baffle and the top plate. One end of the screw is connected to the gear transmission assembly, and the other end of the screw is connected to the second baffle. A pressure sensor is disposed between the clamping mechanism and the spring base plate; A displacement sensor is mounted on the clamping mechanism and passes through the spring base plate and the second baffle. The limiting block is detachably located between the second baffle and the spring base plate.

2. The battery expansion force testing device according to claim 1, characterized in that, The clamping mechanism includes a third baffle, a first clamping plate, a second clamping plate, and a fourth baffle arranged sequentially from top to bottom. The third baffle is fixedly connected to the spring base plate, the first clamping plate is fixedly installed on the lower surface of the third baffle, and the second clamping plate is fixedly installed on the upper surface of the fourth baffle.

3. The battery expansion force testing device according to claim 2, characterized in that, The clamping mechanism further includes a tab clamping head assembly for clamping the battery tabs extending between the first clamping plate and the second clamping plate, the tab clamping head assembly being disposed on the side of the fourth baffle.

4. The battery expansion force testing device according to claim 3, characterized in that, The electrode clamp head assembly includes a clamp head base mounted on the side of the fourth baffle, a clamp head slide plate slidably mounted on the clamp head base, and an electrode clamp head mounted on the clamp head slide plate. The electrode clamp head is provided with a voltage line plate and a current line plate.

5. The battery expansion force testing device according to claim 1, characterized in that, The gear transmission assembly includes a gear box, a large gear rotatably disposed within the gear box, and a small gear meshing with the large gear. The gear box is fixedly connected between the top plate and the first baffle. The large gear is coaxially connected to a drive shaft, which passes upward through the top plate and is coaxially connected to a drive component. The small gear is connected to the screw.

6. The battery expansion force testing device according to claim 5, characterized in that, There are two pinions, which are symmetrically meshed on both sides of the large gear.

7. The battery expansion force testing device according to claim 2, characterized in that, It also includes a guide post, one end of which is fixedly connected to the first baffle, and the other end of which passes through the second baffle, the spring base plate, the third baffle and is fixedly connected to the fourth baffle.

8. The battery expansion force testing device according to claim 2, characterized in that, The pressure sensor is fixedly installed on the upper surface of the third baffle, and the pressure sensor is connected to an external data acquisition system.

9. The battery expansion force testing device according to claim 2, characterized in that, The housing of the displacement sensor is mounted on the upper surface of the third baffle. The probe of the displacement sensor passes upward through the spring base plate and the second baffle in sequence. The displacement sensor is connected to an external data acquisition system.

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