Lithium ion battery top cover welding strength monitoring device

Abstract

The utility model discloses a lithium ion battery top cover welding strength monitoring device, and relates to the technical field of lithium ion battery top cover welding, a 3D camera is added to monitor the width of a welding wire in the battery top cover welding process, the width of the welding wire can macroscopically feed back the fluctuation of a molten pool in the welding process, and the 3D camera is added to monitor the change of the width of the welding wire, so that the welding strength of the battery top cover is monitored. Therefore, the change of the effective penetration and the maximum penetration of the cell welding pool can be macroscopically monitored, and non-destructive detection can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery top cover welding, in particular to a lithium ion battery top cover welding strength monitoring device. Background Art

[0002] Lithium-ion batteries, with their advantages of high specific energy, high battery voltage, wide operating temperature range and long storage life, have been widely used in military and civilian small electrical appliances, such as mobile phones, portable computers, camcorders, cameras, etc., and have partially replaced traditional batteries. In the production process of lithium-ion batteries, top cover welding is an extremely important production step, which involves the safety performance and battery life of the battery. In the process of top cover welding, high-precision control and stable operating equipment are required. At present, the mainstream method on the market is laser welding of top covers. Laser welding is a high-precision and high-efficiency welding method. It generates local high temperature on the surface of the top cover by focusing the laser beam, so that the top cover material melts and forms a weld. Laser welding has the advantages of fast welding speed, high weld quality and small welding deformation. In the laser welding process, the welding device and the positioning device are arranged at intervals along the transmission direction of the feeding conveyor belt, and the welding device includes a laser welding mechanism and an auxiliary welding mechanism. When the carrier moves to the bottom of the auxiliary welding mechanism, the auxiliary welding mechanism can press the battery cell and drive the battery cell to rotate, and the laser generated by the laser welding mechanism can be gathered at the outer edge of the top cover.

[0003] The laser welding of the top cover needs to take into account the sealing and mechanical strength of the battery cell. The sealing of the battery cell can be determined through the subsequent battery cell leak detection process, which can achieve full inspection, but the mechanical strength of the battery cell is a destructive test, which can be achieved through the battery cell pressure test and the metallographic inspection of the battery cell molten pool. The pressure test is to inflate the battery cell to simulate the gas production in the case of thermal runaway of the battery cell. It is necessary to meet the mechanical strength of the top cover welding greater than the pressure relief strength of the explosion-proof valve. The metallographic inspection of the battery cell molten pool confirms whether the data such as the welding depth and width of the battery cell welding meet the established specifications.

[0004] However, the mechanical strength of the battery cell cannot be fully inspected. When the welding state of the battery cell changes, such as the welding trajectory is offset or the battery cell clamping fixture fails, there is a risk that the energy of the laser acting on the welding workpiece will be reduced, the welding effect between the top cover and the aluminum shell will deteriorate, and the molten pool will become shallower, which cannot meet the established requirements for the depth and width of the welding molten pool. Therefore, the utility model proposes a lithium-ion battery top cover welding strength monitoring device. Utility Model Content

[0005] In order to solve the technical problems existing in the background technology, the utility model provides a lithium-ion battery top cover welding strength monitoring device.

[0006] The utility model proposes a lithium-ion battery top cover welding strength monitoring device, comprising a transmission mechanism, the transmission mechanism is used to transmit the lithium-ion battery top cover after welding, a 3D camera is provided on one side of the transmission mechanism, the 3D camera is used to monitor the width of the welding line of the lithium-ion battery top cover welding, and a lifting mechanism is provided on the 3D camera, and the lifting mechanism is used to drive the 3D camera to rise and fall.

[0007] Preferably, the transmission mechanism includes a driving member and two transmission rollers, a transmission belt is transmission-connected between the two transmission rollers, and mounting seats are provided on both sides of the transmission rollers, the transmission rollers rotate on the mounting seats, the output shaft of the driving member is fixedly connected to one of the transmission rollers, and the driving member is used to drive one of the transmission rollers to rotate.

[0008] Preferably, the driving member is a motor.

[0009] Preferably, the lifting mechanism comprises two fixed plates, wherein a plurality of lifting members are mounted on one of the fixed plates, one end of an output shaft of the lifting member is fixedly connected to the other fixed plate, and the 3D camera is mounted on the other fixed plate.

[0010] Preferably, the lifting member is an electric push rod.

[0011] Preferably, the number of the lifting members is set to four.

[0012] In the utility model, the proposed lithium-ion battery top cover welding strength monitoring device has the following beneficial technical effects:

[0013] By adding a 3D camera to monitor the width of the weld line during the battery top cover welding process, the weld line width can provide macroscopic feedback on the fluctuation of the molten pool during the welding process. By adding a 3D camera to monitor the changes in the weld line width, macroscopic monitoring of the changes in the effective melting depth and maximum melting depth of the battery cell welding molten pool can be achieved, and non-destructive detection can be realized.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top view of the structure of the utility model;

[0016] Figure 2 It is the front view of the lifting mechanism of the utility model.

[0017] In the figure, 1. transmission mechanism; 11. transmission roller; 12. transmission belt; 13. mounting seat; 14. driving member; 2. 3D camera; 3. lifting mechanism; 31. fixing plate; 32. lifting member. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0019] like Figure 1-Figure 2 A lithium-ion battery top cover welding strength monitoring device shown includes a transmission mechanism 1, which is used to transmit the welded lithium-ion battery top cover. A 3D camera 2 is provided on one side of the transmission mechanism 1. The 3D camera 2 is used to monitor the width of the welding line of the lithium-ion battery top cover. A lifting mechanism 3 is provided on the 3D camera 2, and the lifting mechanism 3 is used to drive the 3D camera 2 to rise and fall. The 3D camera 2 is a 3D digital camera in the prior art, which refers to a digital camera that can appreciate three-dimensional images or animations with naked eyes.

[0020] A further improvement of the technical solution is that the transmission mechanism 1 includes a driving member 14 and two transmission rollers 11, a transmission belt 12 is transmission-connected between the two transmission rollers 11, and mounting seats 13 are provided on both sides of the transmission rollers 11, the transmission rollers 11 rotate on the mounting seats 13, the output shaft of the driving member 14 is fixedly connected to one of the transmission rollers 11, and the driving member 14 is used to drive one of the transmission rollers 11 to rotate.

[0021] In an optional embodiment, the driving member 14 is a motor.

[0022] A further improvement of the technical solution is that the lifting mechanism 3 includes two fixed plates 31 , one of which is provided with a plurality of lifting members 32 , one end of the output shaft of the lifting member 32 is fixedly connected to the other fixed plate 31 , and the 3D camera 2 is installed on the other fixed plate 31 .

[0023] In an optional embodiment, the lifting member 32 is an electric push rod.

[0024] In an optional embodiment, the number of the lifting members 32 is set to four.

[0025] A further improvement of the technical solution is that the lifting mechanism 3 can be replaced by other existing lifting structures that can achieve lifting.

[0026] The purpose is to monitor the width of the weld line during the battery top cover welding process. The weld line width can provide macroscopic feedback on the fluctuation of the molten pool during the welding process. By adding 3D camera 2 to monitor the changes in weld line width, macroscopic monitoring of the changes in the effective melting depth and maximum melting depth of the battery cell welding molten pool can be achieved, and non-destructive detection can be realized.

[0027] Increase the width of the welding line detected by 3D camera 2 after welding:

[0028] During welding, the deviation of the weld line will cause fluctuations in the weld width and depth of the molten pool. Specifically, when the welding conditions change (such as failure of the welding clamping tooling, laser beam deviation), the weld line width will become smaller, so a 3D camera 2 can be added to detect the decrease in the weld line width, and macro feedback can be provided on the decrease in the effective weld depth and maximum weld depth of the internal molten pool.

[0029] Effective melting depth: the depth of the molten pool at the joint of the aluminum shell and cover plate of the lithium-ion battery top cover;

[0030] Maximum penetration depth: The maximum depth of the molten pool on the welded workpiece when the laser beam acts on it. The effective penetration depth is the feedback of the welding strength;

[0031] Adding 3D camera 2 can detect the change of welding line width at a macroscopic level.

[0032] The setting of the welding line width specification is based on the thickness of the current mainstream top cover and aluminum shell. The recommended setting value is 1.3~1.7mm, which can be set after verification according to actual conditions.

[0033] In this embodiment, it is necessary to add a 3D camera 2 to detect changes in the width of the welding line, and at the same time set the specification value of the welding line width according to the verification result. The verified specification value is a variable value. The 1.3-1.7 mm in this application is a reference value given based on the thickness after the mainstream battery cell is matched.

[0034] When the welding of the battery cell top cover is completed, the 3D camera 2 scans the welding effect and determines the weld line width. Based on the principle of this application, the specification value of the weld line width is set, the result is determined, and the changing trend of the effective melting depth and the maximum melting depth inside the molten pool is macro-monitored. If any deviation occurs, the welding tooling and welding laser beam are adjusted in time.

[0035] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0036] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A lithium-ion battery top cover welding strength monitoring device, characterized in that: The invention comprises a transmission mechanism (1), wherein the transmission mechanism (1) is used to transmit a lithium-ion battery top cover after welding; a 3D camera (2) is provided on one side of the transmission mechanism (1); the 3D camera (2) is used to monitor the width of a welding line of the lithium-ion battery top cover; and a lifting mechanism (3) is provided on the 3D camera (2); and the lifting mechanism (3) is used to drive the 3D camera (2) to rise and fall.

2. The lithium-ion battery top cover welding strength monitoring device according to claim 1, characterized in that: The transmission mechanism (1) comprises a driving member (14) and two transmission rollers (11); a transmission belt (12) is connected between the two transmission rollers (11); mounting seats (13) are provided on both sides of the transmission rollers (11); the transmission rollers (11) rotate on the mounting seats (13); an output shaft of the driving member (14) is connected to one of the transmission rollers (11); and the driving member (14) is used to drive one of the transmission rollers (11) to rotate.

3. The lithium-ion battery top cover welding strength monitoring device according to claim 2, characterized in that: The driving member (14) is a motor.

4. The lithium-ion battery top cover welding strength monitoring device according to claim 1, characterized in that: The lifting mechanism (3) comprises two fixed plates (31), one of the fixed plates (31) being provided with a plurality of lifting members (32), one end of an output shaft of the lifting member (32) being connected to the other fixed plate (31), and the 3D camera (2) being provided on the other fixed plate (31).

5. The lithium-ion battery top cover welding strength monitoring device according to claim 4, characterized in that: The lifting member (32) is an electric push rod.

6. The lithium-ion battery top cover welding strength monitoring device according to claim 4, characterized in that: The number of the lifting members (32) is set to four.

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