Battery leakage point detection device and system

Abstract

The utility model discloses a battery leakage point detection device and system. The battery leakage point detection device comprises a flexible pressure sensor and a fixing device, the battery comprises a battery cover plate and a battery shell, and the battery cover plate is provided with a battery pole and a liquid injection port; the flexible pressure sensor is detachably connected to the fixing device; the fixing device is used for driving the flexible pressure sensor to be close to or away from the battery cover plate; when the flexible pressure sensor is close to the battery cover plate, the flexible pressure sensor covers the sealing position of the battery cover plate, is tightly attached to the battery cover plate and is used for detecting a leakage point. According to the battery leakage point detection device and system, the flexible pressure sensor is adopted to detect the battery leakage point, helium and a helium detector are omitted, the cost is low, the specific leakage point position can be detected, the analysis of the leakage point generation reason, the improvement of the process and the like are facilitated, the yield of the battery cell is improved, and the operation is simple and convenient.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium-ion battery production, and specifically relates to a battery leak point detection device and system. Background Art

[0002] In recent years, the increasingly serious energy crisis and greenhouse effect have promoted the global development of clean energy. Lithium-ion batteries have developed by leaps and bounds due to their excellent characteristics such as high energy density, high output voltage, long service life, good cycle performance, low self-discharge rate, no memory effect, and environmental friendliness, and are widely used in many fields such as electric vehicles and electronic products. With the continuous expansion of the use range of lithium-ion batteries, their safety performance has gradually become the focus of attention. As one of the possible safety hazards, battery leakage not only affects the performance of the battery, but may also cause damage to equipment and users. Therefore, it is of great practical significance to detect the leak points of lithium-ion batteries.

[0003] The housing of the battery is composed of a battery case and a battery cover plate welded together, which is a key component for sealing and protecting the battery core. If there is a leak point, it will cause the electrolyte to overflow, reduce the battery capacity, corrode the components, and at the same time, moisture may enter the battery and affect its electrical performance, and even affect its safety performance. At present, after welding the battery cover plate, the helium leak detection method is generally used to detect the airtightness of the cover plate. During the production of square and cylindrical lithium-ion batteries, helium leak detection is carried out twice. The first time is after welding the cover plate and the housing, and the second time is after welding the sealing nail. Chinese Patent Publication No. CN220982587U discloses a battery helium leak detection device, which uses the helium leak detection method to detect the leak points of the battery, specifically referring to the second helium leak detection.

[0004] However, using the helium leak detection method to detect battery leakage has the following disadvantages: when several batteries are detected by one device at the same time, if there are defective products, individual batteries still need to be tested to determine, and the detection efficiency is low; the detection process is divided into two steps and takes a long time; helium gas and a helium leak detector are required, and the cost is high; a certain amount of helium gas needs to be injected into the battery before the second helium leak detection, but it is impossible to judge whether it has been injected. If there is no helium gas in the battery, it will affect the detection result and may cause defective batteries to be delivered to customers; it can only judge whether the leakage rate meets the requirements and cannot detect the specific leak point location. In order to avoid the many disadvantages of the above helium leak detection method, a device that does not use helium gas is proposed to detect battery leakage. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a battery leak point detection device and system for the above deficiencies, which realizes the detection of battery leak points without using helium gas and a helium leak detector, can also detect the specific leak point location, has a lower cost, and is easy to operate. To achieve the above purpose, the utility model provides the following technical solutions:

[0006] A battery leakage detection device, comprising a flexible pressure sensor and a fixing device;

[0007] The battery includes a battery cover plate and a battery housing, and a battery terminal post and a liquid injection port are provided on the battery cover plate;

[0008] The flexible pressure sensor is detachably connected to the fixing device;

[0009] The fixing device is used to drive the flexible pressure sensor to approach or move away from the battery cover plate;

[0010] When the flexible pressure sensor approaches the battery cover plate, the flexible pressure sensor covers the seal of the battery cover plate and is closely attached to the battery cover plate for detecting leakage points.

[0011] Furthermore, an air inlet pipe is provided on the fixing device; the air inlet pipe is used to communicate with the liquid injection port to inflate the battery.

[0012] Furthermore, the flexible pressure sensor includes an avoidance hole, and the avoidance hole is used to avoid the battery terminal post and the liquid injection port.

[0013] Furthermore, the flexible pressure sensor includes a main body part and an extension part. The main body part is used to cover the battery cover plate, and the extension part is used to cover the seal connection between the battery cover plate and the battery housing, and / or the extension part is used to cover the seal connection between the battery terminal post and the battery cover plate.

[0014] Furthermore, the fixing device includes an avoidance recess, and the avoidance recess is used to avoid the battery terminal post, and the avoidance recess is arranged corresponding to the avoidance hole.

[0015] Furthermore, a flexible pressure sensor is provided at the connection between the avoidance recess and the fixing device; the side wall of the avoidance recess is used to cover the extension part of the flexible pressure sensor on the seal connection between the battery terminal post and the battery cover plate.

[0016] Furthermore, a spacer bar is provided on the surface of the flexible pressure sensor facing the battery cover plate; the spacer bar divides the flexible pressure sensor into several independent detection units.

[0017] Furthermore, it further includes a base and a driving mechanism; the driving mechanism is arranged on the base, and the output end of the driving mechanism is connected to the fixing device and is used to drive the fixing device to approach or move away from the battery cover plate.

[0018] Furthermore, it further includes a battery limiting structure; the battery limiting structure is arranged on the base, and the battery limiting structure is used to fix the battery.

[0019] A battery leak detection system includes a sealed cavity and the above-mentioned battery leak detection device; the sealed cavity is used to seal the battery leak detection device.

[0020] The beneficial effects of the present utility model are:

[0021] The present utility model discloses a battery leak detection device and system, including a flexible pressure sensor and a fixing device; the battery includes a battery cover plate and a battery case, and a battery terminal post and a liquid injection port are provided on the battery cover plate; the flexible pressure sensor is detachably connected to the fixing device; the fixing device is used to drive the flexible pressure sensor to approach or move away from the battery cover plate; when the flexible pressure sensor approaches the battery cover plate, the flexible pressure sensor covers the sealing part of the battery cover plate and is closely attached to the battery cover plate for detecting leaks. For the battery leak detection device and system of the present utility model, a flexible pressure sensor is used to detect battery leaks, eliminating the need for helium gas and a helium detector, with low cost. At the same time, the specific leak location can be detected, which helps analyze the cause of the leak, improve the process, etc., improve the yield of the battery cells, and is easy to operate. Description of the Drawings

[0022] Figure 1 is a three-dimensional structural schematic diagram of the present utility model;

[0023] Figure 2 is a structural schematic diagram of the flexible pressure sensor of the present utility model;

[0024] Figure 3 is a three-dimensional structural schematic diagram of the battery and the fixing device of the present utility model;

[0025] Figure 4 is a cross-sectional structural schematic diagram of the fixing device of the present utility model;

[0026] In the drawings: 1 - flexible pressure sensor, 2 - fixing device, 3 - intake pipe, 4 - battery case, 5 - avoidance hole, 6 - avoidance depression, 7 - spacer, 8 - base, 9 - drive mechanism, 10 - battery limiting structure, 11 - battery cover plate, 12 - battery terminal post, 13 - liquid injection port, 14 - main body part, 15 - extension part. Detailed Embodiments

[0027] All the features disclosed in this specification, or all the steps in any method or process disclosed, except for mutually exclusive features and / or steps, can be combined in any manner.

[0028] Any feature disclosed in this specification (including any additional claims and abstract), unless specifically recited, may be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically recited, each feature is only an example of a series of equivalent or similar features.

[0029] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0030] In addition, the terms "first", "second", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0031] The outer shell of the battery is composed of a battery case 4 and a battery cover plate 11 welded together, which is a key component for sealing and protecting the battery cell. A battery terminal 12 and a liquid injection port 13 are provided on the battery cover plate 11, and the liquid injection port 13 is used to inject electrolyte into the battery. The detection of battery leakage mainly refers to the detection of the sealed joints between the battery case 4 and the battery cover plate 11, the sealed joints between the battery terminal 12 and the battery cover plate 11, and the sealed joint of the liquid injection port 13 after the liquid injection port 13 is sealed. Currently, after welding the battery cover plate, helium leak detection is generally used to detect the welded and sealed joints between the battery case and the battery cover plate. During the production of square and cylindrical batteries, helium leak detection is carried out twice. The first time is after welding the cover plate and the case, and the second time is after welding the sealing nail. The present utility model exemplarily provides a battery leakage detection device that does not require helium for detection.

[0032] Embodiment 1:

[0033] This embodiment is described by taking a square battery as an example. It should be understood that the design concept and principle of this solution are equally applicable to circular batteries.

[0034] Figures 1 to 4The illustrated utility model is an example in an embodiment. In this embodiment, a battery leak point detection device includes a flexible pressure sensor 1 and a fixing device 2. A detachable flexible pressure sensor 1 is provided on the side of the fixing device 2 facing the battery cover plate. The contact surface where the flexible pressure sensor 1 is connected to the fixing device 2 can adopt materials such as PI, PET, and PP. Then, the flexible pressure sensor 1 is fixed to the fixing device 2 using double-sided tape. It can be understood that the flexible pressure sensor 1 can also be connected to the fixing device 2 through a detachable connector or the like. The fixing device 2 is used to drive the flexible pressure sensor 1 to approach or move away from the battery cover plate 11. When the flexible pressure sensor 1 approaches the battery cover plate 11, the flexible pressure sensor 1 covers the seal of the battery cover plate 11 and fits tightly with the battery cover plate 11 to detect leak points.

[0035] An air inlet pipe 3 is provided on the fixing device 2. When the fixing device 2 covers the battery cover plate 11, the position of the air inlet pipe 3 corresponds to the position of the liquid injection port 13 on the battery cover plate 11. When detecting the battery leak point, gas is filled into the battery through the air inlet pipe 3 from the liquid injection port 13. The fixing device 2 and the air inlet pipe 3 can be connected by screw fit. A connection hole is provided at the position on the fixing device 2 where it is connected to the air inlet pipe 3, and a matching thread is provided on the connection hole wall. The other end of the air inlet pipe 3 and the equipment pipe can be connected in a detachable manner such as by a clamp, screw, flange, etc., which is convenient for disassembly or assembly and facilitates repair or replacement when damaged.

[0036] This practical battery leak point detection device further includes a base 8, a battery limiting structure 10, and a driving mechanism 9. The battery limiting structure 10 and the driving mechanism 9 are fixed on the base 8. The output end of the driving mechanism 9 is connected to the fixing device 2 to drive the fixing device 2 to approach or move away from the battery cover plate 11; the battery limiting structure 10 is used to place the battery to be detected.

[0037] The driving mechanism 9 can be a telescopic rod. The telescopic rod is connected to the fixing device 2 through a connecting block, and the telescopic rod drives the fixing device 2 to lift when it works.

[0038] When detecting the leakage point of the battery, the driving mechanism 9 is started to drive the fixing device 2 to move closer to the battery until the flexible pressure sensor 1 covers the sealing position of the battery cover plate 11. The sealing position mainly refers to the welded joints of the battery cover plate 11 and the battery case 4, and the battery pole column 12 and the battery cover plate 11. Because the battery cover plate 11 and the battery case 4 are welded during the battery assembly process, defects such as explosion points, sand holes, air holes, and insecure welding may occur. Therefore, the detection of battery leakage points mainly focuses on the welded joint of the battery cover plate 11 and the battery case 4. Specifically, the flexible pressure sensor 1 can be set as a main body part 14 and an extension part 15. The main body part 14 is used to cover the battery cover plate, and the extension part 15 is used to cover the welded joint of the battery cover plate 11 and the battery case 4 and the welded joint of the battery pole column 12 and the battery cover plate 11. Therefore, the flexible pressure sensor 1 can be set at the position corresponding to the welded joint of the battery cover plate 11 and the battery case 4 and the position corresponding to the welded joint of the battery pole column 12 and the battery cover plate 11.

[0039] The shape of the fixing device 2 is Figure 1 As shown in the figure, when it is set in the shape of a cover plate with an open bottom, the flexible pressure sensor 1 is closely attached to the welded position of the battery cover plate 11 and the battery case 4 and the welded position of the battery pole column 12 and the battery cover plate 11. If there is a leakage point in the battery case 4, the gas will overflow from the leakage point. The flexible pressure sensor 1 at this place is affected by the force of the gas on it, and immediately triggers the electrical signal (such as resistance, capacitance, etc.) in the flexible pressure sensor 1, then the battery leakage point can be detected and the specific leakage point can be found. A battery leakage point detection device of the present utility model detects the battery leakage point by using the flexible pressure sensor 1. Since the principle of using the flexible pressure sensor 1 is that the electrical signal will change under the action of the gas force, the gas filled into the battery does not have to be helium, and it can also be air, thus eliminating the use of a helium detector, reducing the detection cost, and also being able to find the specific position of the leakage point on the battery case 4, providing help for subsequent analysis of the cause of the leakage point, improvement of the process, etc., improving the yield of the battery core, and being easy to operate.

[0040] Figure 2A schematic diagram of the flexible pressure sensor 1 is shown. The flexible pressure sensor 1 consists of a flexible pressure sensor array and a circuit board. The flexible pressure sensor array can be made of a flexible substrate (such as PET) and a conductive metal (such as silver paste, etc.) to form flexible electrodes, and assembled with a flexible piezoresistive (or other principle type) material (such as PDMS + graphene carbon nanowalls, etc.). Due to the material characteristics, the flexible pressure sensor array can be flexibly made into any shape to adapt to battery covers 11 of different shapes and sizes. The size of the array units of the flexible pressure sensor array can also be adjusted. The smaller the unit, the higher the resolution of the measured pressure distribution map. A number of wires are embedded in the flexible pressure sensor array, and the wires are connected to the circuit board. The electrical signals generated by the flexible pressure sensor array are led out by the wires and transmitted to the circuit board, and the electrical signals can be transmitted to the terminal in a wired or wireless manner. The terminal is a mobile phone, a desktop computer, a laptop, etc., and can detect the magnitude and distribution of the pressure in real time. When there is a leak point in the battery cover 11, the position of the flexible pressure sensor array corresponding to the leak point position of the battery cover 11 is subjected to the force of the gas on it, and then the electrical signals (such as resistance, capacitance, etc.) change. The electrical signals are transmitted to the circuit board through the wires and sent to the terminal. In this way, the battery leak point can be detected and the specific position of the leak point on the battery cover 11 can be detected, and the magnitude and distribution of the pressure can also be seen, which provides help for subsequent analysis of the cause of the leak point and improvement of the process, etc.

[0041] Specifically, a plurality of avoidance holes 5 are provided on the flexible pressure sensor 1. The avoidance holes 5 correspond one-to-one to the battery terminal posts 12 and the liquid injection ports 13 on the battery cover 11. The avoidance holes 5 are used to avoid the battery terminal posts 12, so that the flexible pressure sensor 1 can better fit at the sealed connection between the battery cover 11 and the battery terminal posts 12, and avoid the liquid injection ports 13, so that the intake pipe 3 is communicated with the liquid injection ports 13, facilitating inflation of the battery. A number of spacer bars 7 are provided at one end of the flexible pressure sensor 1 facing the battery cover 11. The number of spacer bars 7 can be perpendicular to each other, dividing the flexible pressure sensor 1 into a number of detection units, so that the battery cover can be subjected to leak point detection by region. When the driving mechanism 9 drives the fixing device 2 to move downward and presses the flexible pressure sensor 1 on the sealed portion of the battery cover 11, the flexible pressure sensor 1 not only fits more closely with the battery housing 4, but also forms a number of detection units. The leak points in the local area of the battery cover can be detected by individual detection units. In this way, the specific position of the detected leak point is more accurate, and it is also convenient to analyze the severity of leakage in different leak point areas.

[0042] Figure 3 and Figure 4The figure shows a schematic diagram of how the fixing device 2 is arranged at the position corresponding to the battery pole 12. At the position corresponding to the battery pole 12 on the battery cover plate 11 of the fixing device 2, there is an avoidance recess 6. The position of the avoidance recess 6 corresponds to the positions of the battery pole 12 and the avoidance hole 5, and is used to avoid the battery pole 12 and the liquid injection hole 13. When the fixing device 2 covers the battery cover plate 11, damage to the battery pole 12 by the fixing device 2 is avoided. Flexible pressure sensors 1 are provided at and near the connection between the avoidance recess 6 and the fixing device 2. When the fixing device 2 covers the battery cover plate 11, the side wall of the avoidance recess 6 can better fit the extension part 15 of the flexible pressure sensor 1 to the sealed connection between the battery pole 12 and the battery cover plate 11, and leakage points at the connection between the battery cover plate 11 and the battery pole 12 can also be detected well. It should be noted that the avoidance recess 6 can be a groove structure or a through-hole structure, as long as it can accommodate the battery pole 12. It can be specifically set according to the size of the battery pole 12 and is not limited here.

[0043] The following describes the working process of the first leak detection of the battery by the detection device in combination with the above battery leak point detection device of the present utility model:

[0044] Manufacture the fixing device 2 and the battery limiting structure 10 according to the specific shape and size of the battery. The flexible pressure sensor 1 can be fixed on the fixing device 2 by means of adhesive pasting. Then, fix the fixing device 2 on the driving mechanism 9, assemble the air inlet pipe 3 with the fixing device 2, and align the air inlet pipe 3 with the liquid injection port 13 of the battery cover plate 11. Then place the battery on the battery limiting structure 10, and the driving mechanism 9 drives the fixing device 2 to descend until the flexible pressure sensor 1 covers the battery cover plate 11, and tightly fits the sealed parts of the battery case 4, the battery cover plate 11 and the battery pole 12. Then, fill dry gas into the air inlet pipe 3, which enters the battery case 4 through the liquid injection port, and start leak detection.

[0045] Embodiment 2:

[0046] A battery leak detection system includes a sealed chamber and at least one battery leak detection device of Embodiment 1. The sealed chamber is used to accommodate the sealed battery leak detection device of Embodiment 1 for secondary leak detection. During the secondary leak detection, the liquid injection port 13 on the battery cover plate 11 is in a sealed state, and the avoidance hole 5 can be omitted at the position of the flexible pressure sensor 1 corresponding to the liquid injection port 13. At the same time, the air inlet pipe 3 on the fixing device 2 can also be omitted, and only the avoidance hole 5 is provided at the position corresponding to the battery terminal 12. Then, place the battery on the battery limiting structure 10 of the battery leak detection device of Embodiment 1, and then put it into the sealed chamber, and finally perform secondary leak detection. Specifically: First, place the battery on the battery limiting structure 10 of the battery leak detection device of Embodiment 1, then place the entire detection device with the battery into the sealed chamber, evacuate the sealed chamber, the driving mechanism 9 descends, driving the fixing device 2 to descend until the flexible pressure sensor 1 covers and closely fits the sealed part of the battery cover plate 11. If there is a leak at the sealed part of the battery cover plate 11, due to the pressure difference, the gas inside the battery will escape, exerting a force on the flexible pressure sensor 1, and the magnitude of the force and the specific position of the leak are detected.

[0047] The battery leak detection system can be used to detect leaks in multiple batteries. At this time, it includes multiple battery leak detection devices of Embodiment 1. Multiple battery limiting structures 10 are provided on the base 8, a battery is placed on each battery limiting structure 10, and multiple fixing devices 2 are assembled on the driving mechanism 9. Each fixing device 2 corresponds to a battery, and the air inlet pipe 3 on each fixing device 2 is connected to the equipment pipeline. In this way, multiple batteries can be detected for leaks simultaneously. When performing secondary leak detection on the batteries, the air inlet pipe 3 on each fixing device 2 can be removed, and then the multiple battery leak detection devices are sealed with the sealed chamber.

[0048] It should be noted that the sealed chamber can also not be set separately, but the battery limiting structure 10 in Embodiment 1 is set as a sealed chamber structure for the first or second leak detection. The liquid injection port 13 is set in a sealed state. Specifically, the avoidance hole 5 is reserved at the position of the flexible pressure sensor 1 corresponding to the liquid injection port 13, and the air inlet pipe 3 on the fixing device 2 communicates with the sealed chamber through the avoidance hole 5. The driving mechanism 9 descends, driving the fixing device 2 to descend until the flexible pressure sensor 1 covers and closely fits the sealed part of the battery cover plate 11. Since the liquid injection port 13 is in a sealed state, the air inlet pipe 3 only evacuates the sealed chamber. If there is a leak at the sealed part of the battery cover plate 11, due to the pressure difference, the gas inside the battery will escape, exerting a force on the flexible pressure sensor 1, and the magnitude of the force and the specific position of the leak are detected.

[0049] The above are only the preferred embodiments of the present utility model, and thus do not limit the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present utility model.

Claims

1. A battery leakage detection device, characterized in that: It comprises a flexible pressure sensor (1) and a fixing device (2); The battery comprises a battery housing (4) and a battery cover plate (11); the battery cover plate (11) is provided with a battery pole (12) and a liquid injection port (13); The flexible pressure sensor (1) is detachably connected to the fixing device (2); The fixing device (2) is used to drive the flexible pressure sensor (1) to move closer to or away from the battery cover (11); When the flexible pressure sensor (1) is close to the battery cover (11), the flexible pressure sensor (1) covers the sealing part of the battery cover (11) and fits tightly with the battery cover (11) to detect leakage points.

2. A battery leakage detection device according to claim 1, characterized in that: An air intake pipe (3) is provided on the fixing device (2); the air intake pipe (3) is used to communicate with the liquid injection port (13) to inflate the battery.

3. A battery leakage detection device according to claim 1, characterized in that: The flexible pressure sensor (1) comprises an avoidance hole (5); the avoidance hole (5) is used to avoid the battery pole (12) and the liquid injection port (13).

4. A battery leakage detection device according to claim 1, characterized in that: The flexible pressure sensor (1) comprises a main body (14) and an extension (15); the main body (14) is used to cover the battery cover (11); the extension is used to cover the sealed connection between the battery cover (11) and the battery housing (4), and / or the extension is used to cover the sealed connection between the battery pole (12) and the battery cover (11).

5. A battery leakage detection device according to claim 3, characterized in that: The fixing device (2) comprises an avoidance recess (6); the avoidance recess (6) is used to avoid the battery pole (12), and the avoidance recess (6) and the avoidance hole (5) are arranged correspondingly.

6. A battery leakage detection device according to claim 5, characterized in that: A flexible pressure sensor (1) is provided at the connection between the avoidance recess (6) and the fixing device (2); the side wall of the avoidance recess (6) is used to cover the extension of the flexible pressure sensor (1) at the sealed connection between the battery pole (12) and the battery cover plate (11).

7. A battery leakage detection device according to claim 1, characterized in that: A spacer bar (7) is provided on the side of the flexible pressure sensor (1) facing the battery cover plate (11); the spacer bar (7) divides the flexible pressure sensor (1) into a plurality of independent detection units.

8. A battery leakage detection device according to claim 1, characterized in that: It also includes a base (8) and a driving mechanism (9); the driving mechanism (9) is arranged on the base (8), and the output end of the driving mechanism (9) is connected to the fixing device (2) and is used to drive the fixing device (2) to approach or move away from the battery cover (11).

9. A battery leakage detection device according to claim 8, characterized in that: It also comprises a battery limiting structure (10); the battery limiting structure (10) is arranged on the base (8), and the battery limiting structure (10) is used to fix the battery.

10. A battery leakage detection system, characterized in that: It comprises a sealed cavity and at least one battery leakage detection device as claimed in any one of claims 1 to 9; the sealed cavity is used to seal the battery leakage detection device.

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