Ultrasonic welding pseudo soldering detection device suitable for battery tabs

Abstract

The utility model discloses an ultrasonic welding pseudo soldering detection device suitable for a battery tab. The ultrasonic welding pseudo soldering detection device comprises a test platform, a displacement device, a probe, a current source, a main controller, a voltage test device and a temperature identifier, the telescopic end of the displacement device is fixedly connected with the probe, the probe is driven to move towards or away from the test platform, and the voltage test device is connected with the probe; and the displacement device, the current source, the voltage testing device and the temperature identifier are all connected with the main controller. By means of the ultrasonic welding pseudo soldering detection device suitable for the battery electrode lug, online rapid identification of pseudo soldering of the electrode lug can be achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery tabs, in particular to an ultrasonic welding cold welding detection device suitable for battery tabs. Background Art

[0002] With the increasingly serious global warming and the gradual depletion of petrochemical energy, it has become a general trend for new electric vehicles to replace traditional fuel vehicles. As an excellent and stable energy source for electric vehicles, lithium batteries have now been widely used in the field of electric vehicles.

[0003] The quality of lithium batteries determines the safety, endurance and other key issues of lithium-ion electric vehicles. In the lithium battery production process, there is a problem of cold welding in the ultrasonic welding process of the tabs and cover plates. At present, most companies only perform AC internal resistance tests on finished batteries. This test cannot fully identify the situation of cold welding of the tabs, and some samples with abnormal welding that can be identified have been assembled and can only be scrapped. Therefore, it is necessary to develop new methods to detect the welding of the tabs in the welding process to identify bad batteries in advance. Utility Model Content

[0004] The technical problem to be solved by the utility model is to solve the problem that the welding of the pole lug cannot be detected during the welding process.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A device for detecting cold solder joints of an ultrasonic welding of a battery tab comprises a test platform, a displacement device 200, a probe 300, a current source 400, a main controller 500, a voltage test device 600 and a temperature identifier 700; the telescopic end of the displacement device 200 is fixedly connected to the probe 300, driving the probe 300 to move toward or away from the test platform, and the voltage test device 600 is connected to the probe 300; and the displacement device 200, the current source 400, the voltage test device 600 and the temperature identifier 700 are all connected to the main controller 500.

[0007] In an embodiment of the present invention, a limit plate 100 is provided on the test platform; the limit plate 100 is fixedly located in the displacement direction of the probe 300 .

[0008] In an embodiment of the present invention, during detection, the battery tab 10 is placed on the test platform, and the detection area on the battery tab 10 faces the probe 300 .

[0009] In one embodiment of the present invention, the current source 400 is connected to the positive and negative electrodes of the battery tabs 10 .

[0010] In an embodiment of the present invention, the detection area includes a first detection area 21 ; the first detection area 21 is disposed on a connecting piece of the battery tab 10 .

[0011] In an embodiment of the present invention, the probe 300 includes a first probe 310 , and the displacement direction of the first probe 310 is toward the first detection area 21 .

[0012] In an embodiment of the present invention, the detection area includes a second detection area 22 , and the second detection area 22 is disposed on a protection sheet of the battery tab 10 .

[0013] In an embodiment of the present invention, the probe 300 includes a second probe 320 ; the displacement direction of the second probe 320 is toward the second detection area 22 .

[0014] In an embodiment of the present invention, the detection area includes a third detection area 23 ; the third detection area 23 is disposed at a welding position of the battery tab 10 .

[0015] In an embodiment of the present invention, the measuring point of the temperature identifier 700 is set on the third detection area 23 .

[0016] Compared with the prior art, the utility model has the following beneficial effects: it is applied in the production process of lithium-ion batteries, and in the welding process of the winding core, the pole ear, and the connecting piece, the welding quality is identified by testing the resistance value of the ultrasonic welding process between the pole ear and the cover plate, and monitoring the heat generated when the current passes through the welding part. The utility model is different from the conventional resistance detection schemes such as welding tensile test of the welding part, full battery AC, DC internal resistance detection, etc., and can identify the problem of excessive internal resistance caused by cold welding during the welding process, which is conducive to timely adjustment of welding equipment, while saving the production consumables cost caused by poor cold welding and improving battery safety performance.

[0017] The technical solution of the utility model is to output a fixed current to the measured part according to Ohm's law R=U / I, collect the voltage at both ends through the device, and test the internal resistance of the measured part by the device. The resistance test is first performed, and the large resistance is judged. After the resistance judgment is completed, the temperature of the weld mark is identified by the infrared device, and a secondary judgment is performed based on the high-precision infrared temperature identification result. The resistance detection is performed during the process of the pole ear welding in the lithium battery production process to find the pole ear cold welding problem in advance. The detection also monitors the welding resistance of the pole ear and the heat generated by the resistance at the welding point to identify the pole ear cold welding problem at the welding point. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of an ultrasonic welding cold weld detection device suitable for battery tabs according to an embodiment of the utility model.

[0019] Figure 2 Schematic diagram of the detection area of ​​an embodiment of the utility model. DETAILED DESCRIPTION

[0020] In order to facilitate those skilled in the art to understand the technical solution of the utility model, the technical solution of the utility model is further explained in conjunction with the drawings in the specification.

[0021] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] See also Figure 1 As shown, the utility model provides an ultrasonic welding cold welding detection device suitable for battery tabs, including a test platform, a displacement device 200, a probe 300, a current source 400, a main controller 500, a voltage test device 600 and a temperature identifier 700. The telescopic end of the displacement device 200 is fixedly connected to the probe 300, driving the probe 300 to move closer to or away from the test platform, and the voltage test device 600 is connected to the probe 300. In addition, the displacement device 200, the current source 400, the voltage test device 600 and the temperature identifier 700 are all connected to the main controller 500.

[0023] In one embodiment of the utility model, a limit plate 100 is provided on the test platform, and the limit plate 100 is fixed in the displacement direction of the probe 300. During detection, the battery tab 10 is placed on the test platform, and the detection area on the battery tab 10 faces the probe 300. The battery tab 10 drives the probe 300 to push the battery tab 10 through the displacement device 200, and finally the probe 300 and the battery tab 10 are abutted against each other, and the battery tab 10 is abutted against the limit plate 100, at which time, the displacement device 200 stops pushing the battery tab 10. In this embodiment, the displacement device 200 is a displacement sensor.

[0024] See also Figure 1 and Figure 2 As shown, in one embodiment of the present invention, the probe 300 includes a first probe 310 and a second probe 320. A fixed bracket is provided at the telescopic end of the displacement device 200, and the first probe 310 and the second probe 320 are connected to the fixed bracket.

[0025] Correspondingly, the detection area includes a first detection area 21 and a second detection area 22; the first detection area 21 is arranged on the connecting sheet of the battery tab 10. The second detection area 22 is arranged on the protective sheet of the battery tab 10. During detection, the displacement direction of the first probe 310 is toward the first detection area 21, and the displacement direction of the second probe 320 is toward the second detection area 22.

[0026] In one embodiment of the present invention, the detection area includes a third detection area 23. The third detection area 23 is set at the welding position of the battery tab 10, and the measuring point of the temperature identifier 700 is set on the third detection area 23. Specifically, in this embodiment, the temperature identifier 700 is an infrared sensor.

[0027] In one embodiment of the utility model, during detection, the current source 400 is connected to the positive and negative electrodes of the battery tab 10, and a constant current is input to the battery tab 10, and the voltage test device 600 measures the voltage of the first probe 310 and the second probe 320. Among them, the main controller 500 controls the displacement device 200 to start working. When the displacement device 200 pushes the probe 300 to press the battery tab 10), when the displacement signal fed back to the main controller 500 by the displacement device 200 does not change, it means that the battery tab 10 has been against the limit plate 100. At this time, the main controller 500 controls the displacement device 200 to stop pushing the probe 300. In addition, the main controller 500 controls the current source 400 to output a current of a specific duration and a specific size to the battery tab 10. The voltage data measured by the voltage test device 600 and the temperature recognition result of the temperature identifier 700 are fed back to the main controller 500 to determine whether the tab is poorly soldered. Specifically, the main controller 500 is Siemens S7-300, the current source 400 is a constant current source, and the voltage testing device 600 is a pressure gauge.

[0028] See also Figure 1 and Figure 2As shown, in one embodiment of the utility model, the test process is as follows: the battery tab 10 is placed on the test platform, and the detection area on the battery tab 10 faces the probe 300. The displacement device 200 controls the probe 300 to press down, and the probe 300 presses the battery tab 10 down to the limit plate 100, the first probe 310 abuts against the first detection area 21, and the second probe 320 abuts against the second detection area 22, and the displacement device 200 transmits a signal to the main controller 500. The main controller 500 transmits a signal to the current source 400, so that the current source 400 transmits a signal and outputs a specific duration and a specific current. At the same time, the voltage test device 600 obtains the pressure data of the probe 300 and the temperature identifier 700 obtains the surface temperature identification data of the third detection area 23, and feeds the data back to the main controller 500. The detection device continuously outputs a current of a specific fixed value from a current source 400, identifies the voltage of the probes 300 at both ends through a voltage testing device 600, identifies the internal resistance of the detection point using Ohm's law, and monitors the heat generated by the resistance at the welding point according to a temperature identifier 700, and determines whether the tab is poorly soldered based on the internal resistance result and the temperature identification result of the temperature identifier 700.

[0029] Example

[0030] The ultrasonic welding cold weld detection device described above is used for verification.

[0031] See also Figure 1 and Figure 2 As shown, the same specifications and models of tabs, connecting sheets, and protective sheets were used for tab ultrasonic welding. The negative copper tabs were used as test objects and were divided into Group A, Group B, and Group C. Group A had three samples a1, a2, and a3. Group B had three samples b1, b2, and b3. Group C had three samples c1, c2, and c3, and the same group was welded under the same welding parameters.

[0032] The ultrasonic welding parameters of group A are as follows: amplitude 20 μm, energy 200 J, pressure 10 kg / f. The ultrasonic welding parameters of group B are as follows: amplitude 40 μm, energy 500 J, pressure 25 kg / f. The ultrasonic welding parameters of group C are as follows: amplitude 60 μm, energy 800 J, pressure 40 kg / f.

[0033] For the A, B and C groups with set ultrasonic welding parameters, the internal resistance test was carried out by ultrasonic welding cold solder joint detection device. The DC internal resistance test was conducted with a current of 10A and a power-on time of 10S:

[0034] Group A Test:

[0035] The corresponding resistance values ​​are: a1 resistance: 1.13 mΩ, a2 resistance: 1.11 mΩ, a3 resistance: 1.15 mΩ. The recognition result of the temperature identifier 700 is: a1 is identifiable, a2 is identifiable, and a3 is identifiable.

[0036] Group B test:

[0037] The corresponding resistance values ​​are: b1 resistance 0.92mΩ, b2 resistance 0.90mΩ, b3 resistance 0.91mΩ. The recognition result of the temperature identifier 700 is: b1 is unrecognizable, b2 is unrecognizable, and b3 is unrecognizable.

[0038] Group C Test:

[0039] The corresponding resistance values ​​are: c1 resistance 0.85mΩ, c2 resistance 0.84mΩ, c3 resistance 0.81mΩ. The recognition result of the temperature identifier 700 is: c1 is not identifiable, c2 is not identifiable, and c3 is not identifiable.

[0040] For groups A, B and C with set ultrasonic welding parameters, welding tensile tests were performed on the weld marks at the welds.

[0041] Welding tensile test of welds at group A: a1 welding tensile value: 23N, a2 welding tensile value: 21N, a3 welding tensile value: 24N.

[0042] Welding tensile test of welds at group B: b1 welding tensile value: 41N, b2 welding tensile value: 40N, b3 welding tensile value: 40N

[0043] Welding tensile test of welds at group C: c1 welding tensile value: 45N, c2 welding tensile value: 48N, c3 welding tensile value: 47N.

[0044] According to the actual situation, the welding tension is determined to be the lower limit of the specification 40N. The welding tension of groups B and C is qualified, and the welding tension of group A is unqualified. Therefore, the resistance value range can be set to: ≤0.95mΩ, and the corresponding resistance value standard of group A is set to: >0.95mΩ. The resistance value is outside the set range, and the temperature identifier 700 result is: "recognizable" and is judged to be unqualified. The resistance range of groups B and C is: ≤0.95mΩ, the resistance value is within the set range, and the temperature is "unrecognizable", so it can be judged that the welding is normal and qualified.

[0045] For the tabs of this test model, the detection scheme determines whether the tabs are poorly soldered as follows: if the tab resistance test is within the range of ≤0.95mΩ and the temperature identifier 700 is "unrecognizable", it is determined to be qualified; otherwise, it is determined that the tabs are poorly soldered.

[0046] Different types of tabs have different tab sizes and materials, and the corresponding tab resistance values ​​are also different. Therefore, before being applied to the actual production line, the ultrasonic welding cold soldering detection device is first used to detect the internal resistance of this batch of tabs and the identification results of the temperature identifier 700, and combined with the tensile test, the judgment conditions of whether this batch of tabs are cold soldered are obtained. After the judgment conditions are obtained, they are applied to the production line for online detection.

[0047] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0048] The above-described embodiments merely represent implementation methods of the utility model, and the protection scope of the utility model is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the utility model, and all of these belong to the protection scope of the utility model.

Claims

1. An ultrasonic welding cold weld detection device suitable for battery tabs, characterized in that: The device comprises a test platform, a displacement device (200), a probe (300), a current source (400), a main controller (500), a voltage test device (600) and a temperature identifier (700); the telescopic end of the displacement device (200) is fixedly connected to the probe (300) to drive the probe (300) to move toward or away from the test platform, and the voltage test device (600) is connected to the probe (300); and the displacement device (200), the current source (400), the voltage test device (600) and the temperature identifier (700) are all connected to the main controller (500).

2. The ultrasonic welding cold weld detection device according to claim 1, characterized in that: A limit plate (100) is provided on the test platform; the limit plate (100) is fixedly located in the displacement direction of the probe (300).

3. The ultrasonic welding cold weld detection device according to claim 1, characterized in that: During testing, the battery tab (10) is placed on the test platform, and the testing area on the battery tab (10) faces the probe (300).

4. The ultrasonic welding cold weld detection device according to claim 3, characterized in that: The current source (400) is connected to the positive and negative electrodes of the battery tabs (10).

5. The ultrasonic welding cold weld detection device according to claim 3, characterized in that: The detection area comprises a first detection area (21); the first detection area (21) is arranged on a connecting piece of a battery tab (10).

6. The ultrasonic welding cold weld detection device according to claim 5, characterized in that: The probe (300) includes a first probe (310), and the displacement direction of the first probe (310) is toward the first detection area (21).

7. The ultrasonic welding cold weld detection device according to claim 3, characterized in that: The detection area comprises a second detection area (22), and the second detection area (22) is arranged on a protection sheet of the battery tab (10).

8. The ultrasonic welding cold weld detection device according to claim 7, characterized in that: The probe (300) includes a second probe (320); the displacement direction of the second probe (320) is toward the second detection area (22).

9. The ultrasonic welding cold weld detection device according to claim 3, characterized in that: The detection area includes a third detection area (23); the third detection area (23) is arranged at the welding position of the battery tab (10).

10. The ultrasonic welding cold weld detection device according to claim 9, characterized in that: The measuring point of the temperature identifier (700) is arranged on the third detection area (23).

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