Battery shell leakage detection method and detection device

Abstract

The invention provides a battery shell leakage detection method and a battery shell leakage detection device. The battery shell leakage detection method comprises the following steps: sealing an opening of a to-be-detected shell to enable the to-be-detected shell to form a closed cavity; gas with the first pressure is inflated into the closed cavity until the pressure in the closed cavity reaches the preset pressure, and the preset pressure is larger than 50% of the target detection pressure; gas with the second pressure is filled into the closed cavity until the pressure in the closed cavity reaches the target detection pressure, and the first pressure is larger than the second pressure; and detecting whether the to-be-detected shell leaks or not. According to the battery shell leakage detection method and the detection device, the damage to the shell caused by overlarge detection pressure can be avoided, and the detection accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of battery casing leakage detection technology, and more specifically, to a battery casing leakage detection method and detection device. Background Technology

[0002] In the manufacturing process of secondary batteries, especially lithium-ion batteries, ensuring the airtightness of the battery casing, particularly the aluminum casing, is crucial. Even minor leaks in the aluminum casing of lithium batteries can severely affect battery performance and safety. Therefore, detecting leaks in the aluminum casing is one of the key quality control steps in battery manufacturing. Currently, the widely used manual visual inspection method in the industry has significant technical limitations and production efficiency bottlenecks. This method relies on the operator's vision and experience to inspect the surface of the lithium battery aluminum casing, looking for any visible defects such as cracks, scratches, or pinholes.

[0003] This method may have provided basic leakage control in the early stages when production scale was small and product wall thickness was large. However, with the continuous development of battery technology and the rapid expansion of production scale, especially for thin-walled (0.4-2.0mm, especially 0.4-0.8mm) lithium battery aluminum casings designed for lightweight and high energy density requirements, the limitations of manual visual inspection have become particularly prominent.

[0004] On high-throughput production lines, the speed of manual visual inspection cannot keep up with the production requirements of tens of thousands of pieces per day. To meet the inspection speed, it is necessary to increase the number of inspectors and their working hours, which not only increases labor costs but may also lead to worker fatigue and increase the false detection rate. In addition, even in differential pressure testing methods, simply shortening the inflation, pressure stabilization, and testing times will prevent the pressure system from reaching a stable state and establish an accurate testing benchmark, thereby greatly increasing the possibility of missed detections and false judgments, affecting the overall accuracy and reliability of the inspection.

[0005] Increasing the detection pressure can significantly improve the detection capability for micron-level leaks, especially for leaks with diameters in the range of... Pinholes at the 0.01mm level. However, for ultra-thin aluminum shells with a wall thickness of only 0.4mm, high testing pressure may cause elastic or plastic deformation of the shell. This deformation may not only cause physical damage to the product, but also generate "false leakage signals" due to pressure changes in non-leakage factors caused by shell deformation, thus being wrongly judged as defective products, affecting the product pass rate and overall production efficiency. Summary of the Invention

[0006] The main objective of this invention is to provide a method and device for detecting battery casing leakage, which can avoid damage to the casing caused by excessive detection pressure and improve detection accuracy.

[0007] To achieve the above objectives, according to one aspect of the present invention, a battery casing leakage detection method is provided, comprising: sealing the opening of the casing to be tested, thereby forming a sealed chamber; filling the sealed chamber with gas at a first pressure until the pressure inside the sealed chamber reaches a preset pressure, wherein the preset pressure is greater than 50% of the target detection pressure; filling the sealed chamber with gas at a second pressure until the pressure inside the sealed chamber reaches the target detection pressure, wherein the first pressure is greater than the second pressure; and detecting whether the casing to be tested has leaked.

[0008] Furthermore, the first pressure is 1.6P~3P, and the second pressure is 0.6P~1.6P, where P is the target detection pressure.

[0009] Further, the step of filling the sealed chamber with gas at a first pressure until the pressure in the sealed chamber reaches the preset pressure includes: filling the sealed chamber with gas at a first pressure of 0.6P to 1.6P, and making the pressure in the sealed chamber reach the preset pressure in 0.5s to 1.0s.

[0010] Furthermore, the preset pressure is 85% to 95% of the target detection pressure.

[0011] Furthermore, the battery casing leakage detection method also includes: after the pressure in the sealed chamber reaches the target detection pressure, stabilizing the pressure in the sealed chamber, wherein the stabilization time is 0.5s~1.5s.

[0012] Furthermore, the steps for detecting whether the housing under test has leaked include: stabilizing the pressure in the sealed chamber; after the pressure stabilization is completed, detecting the pressure difference change ΔP between the sealed chamber and the standard chamber within a preset time t; and determining whether the housing under test has leaked based on the pressure difference change ΔP.

[0013] Furthermore, the step of determining whether the housing under test has leaked based on the pressure difference change value includes: detecting whether ΔP is greater than a set threshold; if ΔP is greater than the set threshold, it is preliminarily determined that the housing under test is suspected of leaking; if ΔP is less than or equal to the set threshold, it is determined that the housing under test 1 has not leaked.

[0014] Furthermore, if ΔP is greater than the set threshold, the steps for initially determining that the shell under test is suspected of leaking include: if ΔP is greater than the set threshold, analyzing the morphological characteristics of the pressure-time curve of the sealed chamber; if the curve shows a smooth linear decline, determining that the shell under test is leaking; if the curve shows a specific pattern of jitter or a non-linear slow decline, determining it as an interference signal caused by a small deformation of the shell under test, and classifying the shell under test as a qualified product or initiating a re-inspection process.

[0015] Furthermore, the step of sealing the opening of the housing to be tested to form a sealed chamber includes: preparing a sealing fixture, wherein the sealing fixture includes a sealing base and a sealing ring, and the sealing ring is bonded and fixed on the sealing base; placing the sealing fixture over the opening of the housing to be tested, and forming a sealed chamber by pressing the sealing ring against the opening plane of the housing to be tested, wherein the sealing base is made of fluororubber with a Shore A60-70 hardness, and the compression ratio of the sealing ring 4 is 20%~25%.

[0016] Furthermore, the first pressure is 2.8 Bar-4.0 Bar, the second pressure is 1.0 Bar-2.0 Bar, and the target detection pressure is 1.5 Bar.

[0017] According to another aspect of the present invention, a battery casing leakage detection device is provided, applied to any of the aforementioned battery casing leakage detection methods, comprising: a standard chamber for providing a pressure reference for the casing to be tested; a differential pressure sensor for comparing the pressure difference between the standard chamber and the casing to be tested; a solenoid valve assembly mounted on the standard chamber; a sealing fixture for sealing the opening of the casing to be tested; and a controller for electrically connecting to the differential pressure sensor and the solenoid valve assembly.

[0018] Furthermore, the sealing fixture includes a sealing substrate and a sealing ring. The sealing substrate is made of fluororubber with a Shore A hardness of 60-70. The sealing ring is fixedly connected to the sealing substrate. The shape of the sealing ring is adapted to the shape of the housing to be tested. The housing to be tested is embedded in the sealing ring and forms a sealing fit with the sealing ring.

[0019] Furthermore, the compression ratio of the sealing ring is 20% to 25%.

[0020] By applying the technical solution of this invention, the opening of the housing to be tested is sealed to form a closed chamber, ensuring the airtightness of the housing during inflation. Gas at a first pressure is first injected into the closed chamber until it reaches a preset pressure, which is 50% greater than the target detection pressure, thus shortening the time for subsequent inflation of gas at a second pressure. Gas at the second pressure is then injected until it reaches the target detection pressure, employing a two-stage inflation method of "high-pressure sprint + low-pressure fine-tuning." Compared to constant-pressure inflation, this strategy significantly shortens the inflation time, improves the efficiency of testing the sealing performance of the housing, reduces the cycle time, and allows for the testing of more housings within a given time. Simultaneously, it effectively avoids pressure overshoot and pressure fluctuations and transient deformation of the housing caused by violent airflow impact, providing a stable initial state for subsequent testing. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A flowchart of a battery casing leakage detection method according to an embodiment of the present invention is shown;

[0023] Figure 2 This diagram illustrates the structure of the housing to be tested and the sealing fixture before sealing, according to an embodiment of the present invention.

[0024] Figure 3 This diagram illustrates the structure of the housing to be tested after being sealed with the sealing fixture, according to an embodiment of the present invention.

[0025] Figure 4 A cross-sectional view of the housing to be tested and the sealing fixture after sealing is shown according to an embodiment of the present invention;

[0026] Figure 5 A three-dimensional structural schematic diagram of a sealing fixture according to an embodiment of the present invention is shown;

[0027] Figure 6 A three-dimensional structural schematic diagram of an embodiment of the present invention is shown from another perspective.

[0028] The above figures include the following reference numerals:

[0029] 1. Housing to be tested; 2. Sealing fixture; 3. Sealing substrate; 4. Sealing ring; 5. Air inlet. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] See also Figures 1 to 6 As shown, according to an embodiment of the present invention, a battery casing leakage detection method includes: sealing the opening of the casing 1 to be tested, so that the casing 1 to be tested forms a sealed chamber; filling the sealed chamber with gas at a first pressure until the pressure inside the sealed chamber reaches a preset pressure, wherein the preset pressure is greater than 50% of the target detection pressure; filling the sealed chamber with gas at a second pressure until the pressure inside the sealed chamber reaches the target detection pressure, wherein the first pressure is greater than the second pressure; and detecting whether the casing 1 to be tested has leaked.

[0032] In the above technical solution, the opening of the housing 1 to be tested is sealed to form a closed chamber, ensuring the airtightness of the housing 1 to be tested during the inflation process. A higher-pressure gas is first injected into the closed chamber until the pressure reaches a preset pressure, which is greater than 50% of the target detection pressure, shortening the time for subsequent inflation of the second-pressure gas. Then, a lower-pressure gas is injected until the pressure in the sealed chamber reaches the target detection pressure, employing a two-stage inflation method of "high-pressure sprint + low-pressure fine-tuning". Compared with constant-pressure inflation, this strategy significantly shortens the inflation time, improves the efficiency of testing the airtightness of the housing 1 to be tested, shortens the cycle time, and allows for the testing of more housings within a certain time. It also effectively avoids pressure overshoot and pressure fluctuations and transient deformation of the housing caused by violent airflow impact, providing a stable initial state for subsequent testing.

[0033] In one embodiment, the first pressure is 1.6P~3P, and the second pressure is 0.6P~1.6P, where P is the target detection pressure.

[0034] In the above technical solution, the first pressure is 1.6P~3P, which is greater than the target detection pressure. A "high-pressure sprint" method is used for rapid inflation. However, after inflation at the first pressure, the preset pressure of the sealed chamber is still lower than the target detection pressure P. The "high-pressure sprint" shortens the inflation time. The second pressure is 0.6P~1.6P, which is close to the target detection pressure P. A "low-pressure fine-tuning" method is used for slow pressure replenishment until the target pressure is precisely reached. This effectively avoids pressure overshoot and pressure fluctuations and transient deformation of the shell caused by violent airflow impact, providing a stable initial state for subsequent testing.

[0035] The target detection pressure P is the pressure required inside the housing 1 to be tested during the test. It can be determined by technicians based on the thickness or material of the housing 1 through experience. Generally speaking, P is positively correlated with the thickness of the housing 1.

[0036] In one embodiment, the preset pressure is 85% to 95% of the target detection pressure.

[0037] In the above technical solution, the preset pressure is 85% to 95% of the target detection pressure. This ensures that the process of "low-pressure fine-tuning" to reach the target detection pressure P by filling the second pressure gas takes a short time, and also ensures that the shell will not experience pressure fluctuations or transient deformation due to pressure overshoot and violent airflow impact when filling the first pressure gas for "high-pressure sprint".

[0038] In one embodiment, the step of filling a sealed chamber with gas at a first pressure until the pressure inside the sealed chamber reaches a preset pressure includes: filling the sealed chamber with gas at a first pressure of 0.6P to 1.6P, and making the pressure inside the sealed chamber reach 85% to 95% of the target detection pressure in 0.5s to 1.0s.

[0039] In the above technical solution, the pressure in the sealed chamber can reach 85%~95% of the target detection pressure in 0.5s-1.0s, which can improve the inflation efficiency in the sealed chamber. Compared with constant pressure inflation, this strategy shortens the total inflation time by more than 40%.

[0040] In one embodiment, the battery casing leakage detection method further includes: after the pressure in the sealed chamber reaches the target detection pressure, stabilizing the pressure in the sealed chamber, wherein the stabilization time is 0.5s to 1.5s.

[0041] In the above technical solution, the pressure stabilization stage is used to eliminate pressure fluctuations caused by turbulence and thermodynamic effects during inflation, allowing the pressure inside the cavity to stabilize rapidly. This provides an accurate reference for subsequent high-precision differential pressure measurements, which is crucial for achieving a low false alarm rate. Based on the optimized inflation strategy, during inflation using the second pressure, gas fluctuations gradually decrease as the difference between the second pressure and the target detection pressure decreases. Compared to the constant pressure inflation process, where the gas pressure in the sealed cavity needs a long time to reach pressure equilibrium after inflation stops due to the large difference between the inflation pressure and the target detection pressure, this embodiment achieves pressure stabilization during the second pressure inflation process, allowing the gas pressure in the sealed cavity to reach pressure equilibrium in a very short time after inflation stops. This ultra-short pressure stabilization window is one of the keys to achieving a total cycle time of less than 8 seconds for inflation and detection, breaking the convention that traditional equipment requires a long pressure stabilization time.

[0042] In one embodiment, the step of detecting whether the housing 1 to be tested has leaked includes: stabilizing the pressure of the sealed chamber; after the pressure stabilization is completed, detecting the pressure difference change ΔP between the sealed chamber and the standard chamber within a preset time t; and determining whether the housing 1 to be tested has leaked based on the pressure difference change ΔP.

[0043] In the above technical solution, the pressure difference ΔP between the sealed chamber and the standard chamber is used to determine whether the shell 1 under test is leaking. By introducing the standard chamber, a simple and low-cost method can be used to determine whether the shell 1 under test is leaking.

[0044] In this embodiment, the main function of the standard chamber is to serve as a pressure reference, used to compare with the pressure changes inside the housing 1 under test, thereby accurately determining the airtightness of the housing 1 under test. The standard chamber has extremely high airtightness, ensuring no gas leakage during the test, and its internal pressure can remain stable for a long time, unaffected by changes in the external environment.

[0045] The volume of the standard chamber should be similar to that of the aluminum shell to be tested in order to reduce pressure reading deviations caused by volume differences. Its internal shape should be designed as regularly as possible to reduce additional pressure fluctuations caused by hydrodynamic effects during the test.

[0046] By measuring the real-time differential pressure between the standard chamber and the test housing 1, the pressure changes between the two chambers can be compared, providing a direct indication of whether there is a leak in the test housing 1. Theoretically, when both the standard chamber and the test aluminum housing are sealed and filled with gas at the same pressure, the pressure in the two chambers should remain consistent. If there is a leak in the test aluminum housing, the pressure inside its chamber will gradually decrease over time, causing a change in the differential pressure with the standard chamber. By monitoring this change, the extent and location of the leak can be determined.

[0047] In one embodiment, the standard chamber may have the same structure as the housing 1 to be tested, and the material of the standard chamber may be stainless steel or aluminum alloy, etc.

[0048] In one embodiment, the step of determining whether the housing 1 to be tested has leaked based on the pressure difference change value includes: detecting whether ΔP is greater than a set threshold; if ΔP is greater than the set threshold, it is preliminarily determined that the housing 1 to be tested is suspected of leaking; if ΔP is less than or equal to the set threshold, it is determined that the housing 1 to be tested has not leaked.

[0049] In the above technical solution, a threshold is set for ΔP, providing the system with a certain error margin. Only when ΔP exceeds the set threshold is a preliminary judgment that the casing 1 under test has leaked, ensuring that the detection work is time-efficient and reliable. The leakage judgment threshold is set to a fixed value (e.g., 10-20 Pa) based on the maximum allowable leakage rate. This threshold ΔP can reliably identify leakage defects with a diameter greater than 0.01 mm, completely eliminating the variability of subjective human judgment.

[0050] In one embodiment, if ΔP is greater than a set threshold, the step of initially determining that the housing 1 to be tested is suspected of leaking includes: if ΔP is greater than the set threshold, analyzing the morphological characteristics of the pressure-time curve of the sealed chamber.

[0051] In the actual testing process, due to the influence of interference signals, it is easy to misjudge that the shell under test 1 is leaking. In order to avoid this situation, after initially judging that the shell under test 1 is leaking based on ΔP, further judgment is needed to determine whether the shell under test 1 is actually leaking or is a misjudgment caused by signal interference.

[0052] In this embodiment, when determining whether the housing 1 under test is leaking, it is necessary not only to compare whether ΔP is greater than a set threshold (e.g., 10-20 Pa), but also to analyze the morphological characteristics of the pressure-time curve in real time. Specifically: if the curve shows a smooth linear decline, the housing 1 under test is determined to be a true leak. If the curve shows a specific pattern of jitter or a non-linear gradual decline, the housing 1 under test is determined to be an interference signal caused by a slight deformation of the housing, and it is classified as a qualified product or a re-inspection process is initiated. This signal analysis technology can effectively distinguish between true leaks and deformation interference, enabling the system to accurately detect micro-leakage problems in the housing 1 under test while ensuring product safety, reducing the false judgment rate to below 0.1%.

[0053] In one embodiment, the step of sealing the opening of the housing 1 to be tested, so that the housing 1 to be tested forms a sealed chamber, includes: preparing a sealing fixture 2, wherein the sealing fixture 2 includes a sealing substrate 3 and a sealing ring 4, the sealing ring 4 being bonded and fixed on the sealing substrate 3; covering the opening of the housing 1 to be tested with the sealing fixture 2, and forming a sealed chamber by pressing the sealing ring 4 against the opening plane of the housing 1 to be tested, wherein the sealing substrate 3 is made of fluororubber with a hardness of Shore A60-70, and the compression ratio of the sealing ring 4 is 20%~25%.

[0054] In the above technical solution, the sealing substrate 3 is made of fluororubber (FKM), and its hardness is strictly limited to Shore A 60-70. In one embodiment, the hardness of the sealing substrate 3 is Shore A 65.

[0055] This hardness range represents the optimal balance point determined after extensive durability testing: Hardness below Shore A60 makes the material prone to creep and permanent deformation under high-speed, high-frequency pressing, leading to seal failure; hardness above Shore A70 requires greater cylinder clamping force, significantly increasing the risk of damaging the thin-walled shell opening. Shore A65 hardness provides optimal elastic protection while ensuring seal durability. The use of fluororubber (FKM) significantly extends the lifespan of the sealing substrate 3 under high-speed, high-frequency operation, reducing downtime for maintenance and ensuring continuous and stable operation of high-throughput production lines. The sealing ring 4 is bonded to the precision-machined sealing substrate 3, with a compression ratio designed at 20%-25% to ensure instantaneous reliable sealing with minimal clamping force. The sealing ring 4 forms a sealed chamber by pressing against the opening plane of the shell 1 under test, ensuring airtightness of the sealing fixture 2 after contact with the shell 1 during testing.

[0056] In one embodiment, the first pressure is 2.8 Bar-4.0 Bar, the second pressure is 1.0 Bar-2.0 Bar, and the target detection pressure is 1.5 Bar.

[0057] In the above technical solution, firstly, rapid inflation is performed with a relatively high initial pressure of 2.8 Bar to 4.0 Bar, so that the cavity pressure reaches 85% to 95% of the target detection pressure (e.g., 1.5 Bar) within 0.5 to 1.0 seconds; then, the pressure is immediately switched to a fine-tuning pressure of 1.0 Bar to 2.0 Bar for slow pressure replenishment until the target pressure is accurately reached.

[0058] See also Figures 2 to 5 As shown, according to an embodiment of the present invention, the battery casing leakage detection device includes: a standard chamber for providing a pressure reference for the casing 1 to be tested; a differential pressure sensor for comparing the pressure difference between the standard chamber and the casing 1 to be tested; a solenoid valve assembly mounted on the standard chamber; a sealing fixture 2 for sealing the opening of the casing 1 to be tested; and a controller for electrically connecting to the differential pressure sensor and the solenoid valve assembly.

[0059] The pressure in the standard chamber needs to be consistent with the target detection pressure inside the housing 1 to facilitate pressure comparison between the standard chamber and the housing 1. The differential pressure sensor can be installed on the standard chamber, the housing 1 to be tested, or the connection structure between the two. It is used to detect the pressure in the standard chamber and the housing 1 to be tested respectively, and generate differential pressure data output. Technicians can use this differential pressure to determine whether the housing 1 to be tested is leaking.

[0060] In one embodiment, the solenoid valve assembly includes a balancing valve connected between the standard chamber and the housing 1 to be tested. When the gas source pressurizes the housing 1, it connects the standard chamber and the housing 1, ensuring that gas is simultaneously introduced into both chambers and maintains consistent gas pressure. Once the pressure in the housing 1 reaches the target detection pressure, a waiting period is required to allow both chambers to reach and stabilize at the target pressure. After this period, the balancing valve can be controlled to disconnect the connection between the standard chamber and the housing 1. At this point, the pressures in the two chambers are isolated. A differential pressure sensor can then detect the pressure difference between the two chambers to determine if a leak has occurred in the housing 1.

[0061] In the above technical solution, the pressure comparison between a reliable standard chamber and the gas inside the housing 1 under test ensures the reliability of the detection results. Through a combined strategy of "safe pressure window" and "signal morphology analysis," the system can reliably detect [the gas] without damaging the thin 0.4mm thick aluminum shell of the housing 1 under test. A micro-leakage of 0.01mm represents a synergistic enhancement effect that cannot be achieved by simply increasing the detection pressure or optimizing the algorithm. The controller, composed of a PLC and HMI, incorporates pre-built pressure control logic and signal analysis algorithms, enabling precise control of the entire collaborative process. The standard chamber, differential pressure sensor, solenoid valve assembly, and sealing fixture 2 form a quickly replaceable independent unit module, facilitating maintenance and replacement and improving work efficiency. The solenoid valve assembly, installed near the sealing fixture, integrates an inflation valve, an exhaust valve, and a balancing valve, resulting in a very short gas path from the valve to the chamber under test, reducing "ineffective volume" and improving response speed—meaning the valve's opening and closing action is instantly reflected in the chamber pressure. The balancing valve in the solenoid valve assembly opens before detection begins, ensuring equal pressure across the differential pressure sensor, effectively "zeroing" the sensor. Once the gas pressure in both the standard and sealed chambers reaches the target detection pressure, the balancing valve closes, facilitating pressure comparison between the two chambers. The balancing valve eliminates baseline errors caused by sensor drift, temperature changes, or differences in initial pressure between the two chambers, enabling the system to detect extremely small pressure changes. The battery casing leakage detection device, employing a rotary or linear layout, integrates at least six of the aforementioned detection stations, achieving a total system capacity exceeding 3750 units per hour (30,000 units per day) through parallel processing.

[0062] See also Figures 5 to 6 As shown, in one embodiment, the sealing fixture 2 includes a sealing base 3 and a sealing ring 4. The sealing base 3 is made of fluororubber with a Shore A hardness of 60-70. The sealing ring 4 is fixedly connected to the sealing base 3. The shape of the sealing ring 4 is adapted to the shape of the housing 1 to be tested. The housing 1 to be tested is embedded in the sealing ring 4 and forms a sealing fit with the sealing ring 4.

[0063] The precise fit between the sealing substrate 3, made of fluororubber with a Shore A hardness of 60-70, and the sealing ring 4 effectively seals the openings of lithium battery aluminum shells of varying wall thicknesses (0.4mm to 2mm), preventing gas leakage and ensuring pressure stability and accuracy during testing. Furthermore, the material's excellent elasticity and wear resistance guarantee long-term sealing performance and tooling durability during high-frequency pressing and releasing dynamic operations. This significantly improves the overall efficiency and reliability of the automated testing system, enabling continuous, stable, and high-precision testing in high-throughput production environments. Figure 4 As shown.

[0064] In one embodiment, the hardness of the sealing substrate 3 is Shore A65.

[0065] The sealing substrate 3 is made of fluororubber material with a Shore A hardness of 65. During the pressing process, it can provide the required sealing pressure to form a stable sealing interface, and also has sufficient elastic recovery ability. This effectively avoids damage to the opening of the lithium battery aluminum shell, which is as thin as 0.4 mm or as thick as 2 mm. This ensures that the sealing tooling can maintain good sealing performance and durability for a long time in a high-speed automated testing environment.

[0066] In one embodiment, the compression rate of the sealing ring 4 is 20% to 25%.

[0067] By setting its compression ratio within an optimized range of 20% to 25%, and combining it with a sealing substrate 3 made of fluororubber with a Shore A60-70 hardness, the sealing ring 4 can instantly form a stable and reliable sealing fit when the housing 1 to be tested is embedded with the sealing ring 4. At the same time, it minimizes the compressive stress on the housing, ensuring that even when facing aluminum housings with large variations in wall thickness during automated high-speed testing, a fast and non-destructive sealing effect can be achieved, significantly improving testing accuracy, product safety, and tooling durability.

[0068] See also Figure 4 As shown, in one embodiment, an air inlet 5 is provided on the sealing substrate 3. The air inlet 5 is connected to the inner cavity of the housing 1 to be tested, and the air source can introduce gas into the housing 1 to be tested through the air inlet 5.

[0069] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0070] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application 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 sequences other than those illustrated or described herein.

[0071] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting battery casing leakage, characterized in that, include: The opening of the housing (1) to be tested is sealed so that the housing (1) to be tested forms a closed chamber; Gas at a first pressure is introduced into the sealed chamber until the pressure inside the sealed chamber reaches a preset pressure, wherein the preset pressure is greater than 50% of the target detection pressure; Gas at a second pressure is introduced into the sealed chamber until the pressure inside the sealed chamber reaches the target detection pressure, wherein the first pressure is greater than the second pressure; Detect whether the housing (1) to be tested is leaking.

2. The battery casing leakage detection method according to claim 1, characterized in that, The first pressure is 1.6P~3P, and the second pressure is 0.6P~1.6P, where P is the target detection pressure.

3. The battery casing leakage detection method according to claim 1, characterized in that, The step of filling the sealed chamber with gas at a first pressure until the pressure inside the sealed chamber reaches the preset pressure further includes: Gas is injected into the sealed chamber at a first pressure of 0.6P to 1.6P, and the pressure in the sealed chamber reaches the preset pressure in 0.5s to 1.0s.

4. The battery casing leakage detection method according to claim 3, characterized in that, The preset pressure is 85% to 95% of the target detection pressure.

5. The battery casing leakage detection method according to claim 1, characterized in that, The battery casing leakage detection method further includes: After the pressure in the sealed chamber reaches the target detection pressure, before detecting whether the shell (1) to be tested has leaked, the sealed chamber is stabilized for a time of 0.5s to 1.5s.

6. The battery casing leakage detection method according to claim 1, characterized in that, The step of detecting whether the housing (1) to be tested is leaking includes: Within a preset time t, the pressure difference change ΔP between the sealed chamber and the standard chamber is detected; The pressure difference change ΔP is used to determine whether the shell (1) to be tested is leaking.

7. The battery casing leakage detection method according to claim 6, characterized in that, The step of determining whether the housing (1) to be tested has leaked based on the pressure difference change includes: Detect whether ΔP is greater than a set threshold; If ΔP is greater than the set threshold, it is preliminarily determined that the shell (1) to be tested is suspected of leaking; If ΔP is less than or equal to the set threshold, it is determined that the housing (1) to be tested has not leaked.

8. The battery casing leakage detection method according to claim 7, characterized in that, The step of preliminarily determining that the housing (1) to be tested has a suspected leak if ΔP is greater than the set threshold further includes: Analyze the morphological characteristics of the pressure-time curve of the sealed chamber; If the curve shows a smooth linear decline, it is determined that the housing (1) to be tested is leaking; If the curve exhibits a specific pattern of jitter or a non-linear gradual decrease, it is determined to be an interference signal caused by a slight deformation of the shell (1) to be tested, and the shell (1) to be tested is classified as a qualified product or a re-inspection process is initiated.

9. The battery casing leakage detection method according to claim 1, characterized in that, The method of sealing the opening of the housing (1) to be tested, so that the housing (1) to be tested forms a closed chamber, further includes: Prepare a sealing fixture (2), which includes a sealing substrate (3) and a sealing ring (4), and the sealing ring (4) is bonded and fixed on the sealing substrate (3); The sealing fixture (2) is placed over the opening of the housing (1) to be tested, and the sealing chamber is formed by pressing the sealing ring (4) against the opening plane of the housing (1) to be tested. The sealing substrate (3) is made of fluororubber with a hardness of Shore A60-70, and the compression ratio of the sealing ring (4) is 20%~25%.

10. The battery casing leakage detection method according to claim 2, characterized in that, The first pressure is 2.8 Bar-4.0 Bar, the second pressure is 1.0 Bar-2.0 Bar, and the target detection pressure is 1.5 Bar.

11. A battery casing leakage detection device, applied to the battery casing leakage detection method according to any one of claims 1 to 10, characterized in that, include: A standard chamber is provided to serve as a pressure reference for the housing (1) to be tested; A differential pressure sensor is used to compare the pressure difference between the standard chamber and the housing (1) to be tested; The solenoid valve assembly is installed on the standard chamber; A sealing fixture (2) is used to seal the opening of the housing (1) to be tested; A controller is provided for electrical connection with the differential pressure sensor and the solenoid valve assembly.

12. The battery casing leakage detection device according to claim 11, characterized in that, The sealing fixture (2) includes a sealing base (3) and a sealing ring (4). The sealing base (3) is made of fluororubber with a Shore A hardness of 60-70. The sealing ring (4) is fixedly connected to the sealing base (3). The shape of the sealing ring (4) is adapted to the shape of the housing (1) to be tested. The housing (1) to be tested is embedded in the sealing ring (4) and forms a sealing fit with the sealing ring (4).

13. The battery casing leakage detection device according to claim 12, characterized in that, The compression rate of the sealing ring (4) is 20%~25%.

Images