Welding effect detection device

Abstract

The utility model discloses a welding effect detection device which comprises a conveying mechanism, a first welding detection mechanism, a second welding detection mechanism, a third welding detection mechanism, a turnover mechanism and a control device. The first welding detection mechanism, the second welding detection mechanism and the third welding detection mechanism are sequentially arranged in the moving direction of the conveying mechanism. The control device is connected with the conveying mechanism, and the control device is configured to control the conveying mechanism to convey the to-be-detected battery cell; the control device is further connected with the first welding detection mechanism, the second welding detection mechanism and the third welding detection mechanism. The control device is configured to receive a first detection result of the first welding detection mechanism, a second detection result of the second welding detection mechanism and a third detection result of the third welding detection mechanism; the control device is further connected with the turnover mechanism and is further configured to control the turnover mechanism to turn over the to-be-detected battery cell when the to-be-detected battery cell moves to the first welding detection mechanism and the second welding detection mechanism.

Description

Technical Field

[0001] The embodiment of the utility model relates to the field of detection technology, and in particular to a welding effect detection device. Background Art

[0002] As an energy storage device, rechargeable lithium-ion batteries (LIBs) have attracted great attention due to their long cycle life, high operating voltage, high specific energy, low self-discharge, and environmental protection. LIBs have been widely used in portable consumer electronics, electric vehicles, and energy storage. During the production process of LIBs, the battery cell is composed of multiple layers of battery cell poles, and each layer of battery cell foil extends a layer of tab foil. After the battery cell foils are aligned, the tab foils are also attached and aligned together. The tab foils need to be welded together to form tabs. Since the tab foils are very thin, at 5 to 12 μm, they are generally welded by ultrasonic welding.

[0003] When ultrasonic welding between foils and between foils and tabs forms a cold weld, the temperature of the tabs will rise, greatly increasing the safety risk of LIBs and reducing the reliability of LIBs. Therefore, it is necessary to evaluate and judge the welding effect of the welding area formed by welding between foils and tabs.

[0004] At present, the evaluation methods for the welding effect of the welding area formed by welding between the foil and the tab are mainly CCD imaging and tensile testing. Among them, CCD imaging is to analyze the area and depth of the weld mark to evaluate its welding effect; the tensile testing method is to test the welding tension between the foils and between the foil and the tab to evaluate its welding effect.

[0005] Since CCD imaging has a low resolution for poor welding, it is easy to cause false positives and missed releases; the tensile test method cannot establish a unified measurement standard between welding tension and welding effect. As a result, CCD imaging and tensile test methods have limitations in evaluating the welding effect between foils and between foils and tabs. Utility Model Content

[0006] The utility model provides a welding effect detection device to achieve the purpose of improving the accuracy of welding detection effect.

[0007] The present invention provides a welding effect detection device, comprising:

[0008] A conveying mechanism, a first welding detection mechanism, a second welding detection mechanism, a third welding detection mechanism, a turning mechanism and a control device;

[0009] The first welding detection mechanism, the second welding detection mechanism, and the third welding detection mechanism are arranged in sequence along the moving direction of the conveying mechanism;

[0010] The control device is connected to the conveying mechanism, and the control device is configured to control the conveying mechanism to transport the battery cell to be tested;

[0011] The control device is also connected to the first welding detection mechanism, the second welding detection mechanism, and the third welding detection mechanism;

[0012] The control device is configured to receive a first detection result of the first welding detection mechanism, a second detection result of the second welding detection mechanism, and a third detection result of the third welding detection mechanism;

[0013] The control device is also connected to the flipping mechanism, and is further configured to control the flipping mechanism to flip the battery cell to be detected when the battery cell to be detected moves to the first welding detection mechanism and the second welding detection mechanism.

[0014] Optionally, it also includes at least one grasping mechanism;

[0015] The control device is also connected to the grasping mechanism, and the control device is also configured to control the grasping mechanism to grasp the designated battery cell to be inspected.

[0016] Optionally, an ultrasonic welding mechanism is also included;

[0017] The control device is also connected to the ultrasonic welding mechanism, and the control device is also configured to control the ultrasonic welding mechanism to weld the tabs of the battery cell.

[0018] Optionally, a feeding mechanism is also included, and the feeding mechanism is used to adjust the spatial position of the battery cell and shape the connecting piece of the battery cell.

[0019] Optionally, the ultrasonic welding mechanism includes a copper welding mechanism and an aluminum welding mechanism.

[0020] Optionally, it further includes a thickness measuring mechanism, and the control device is also connected to the thickness measuring mechanism;

[0021] The thickness measuring mechanism is used to detect the thickness of the tab of the battery cell to be tested.

[0022] Optionally, the first welding detection mechanism includes: a four-probe resistance tester or a two-probe resistance tester.

[0023] Optionally, the probes of the four-probe resistance tester are gold-plated spring probes with a constant needle distance.

[0024] Optionally, the second welding detection mechanism includes: a CCD imager or a CMOS imager.

[0025] Optionally, the third welding detection mechanism includes: a tensile tester.

[0026] Compared with the prior art, the beneficial effect of the utility model is that: the utility model proposes a welding effect detection device, which includes a first welding detection mechanism, a second welding detection mechanism and a third welding detection mechanism. Through the joint use of multiple testing devices and methods, the problem of detection limitations of a single welding effect evaluation method can be eliminated. Using the device to detect welding effects can prevent false positives and omissions, reduce production costs, and improve the reliability of LIBs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural block diagram of a welding effect detection device in an embodiment;

[0028] Figure 2 is a structural block diagram of another welding effect detection device in the embodiment;

[0029] Figure 3 is a structural block diagram of another welding effect detection device in the embodiment;

[0030] Figure 4 It is another result block diagram of a welding effect detection device in the embodiment;

[0031] Figure 5 It is a working flow chart of the detection device in the embodiment;

[0032] Figure 6 : is a control flow chart of the control device in the embodiment. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] Figure 1 is a structural block diagram of the welding effect detection device in the embodiment, refer to Figure 1 , the welding effect detection device includes:

[0035] A conveying mechanism 100, a first welding detection mechanism 200, a second welding detection mechanism 300, a third welding detection mechanism 400, a turning mechanism 500 and a control device 600;

[0036] The first welding detection mechanism 200, the second welding detection mechanism 300, and the third welding detection mechanism 400 are sequentially arranged along the moving direction of the conveying mechanism 100;

[0037] The control device 600 is connected to the conveying mechanism 100, and the control device is configured to control the conveying mechanism to transport the battery cell to be tested;

[0038] The control device 600 is also connected to the first welding detection mechanism 200, the second welding detection mechanism 300, and the third welding detection mechanism 400;

[0039] The control device 600 is configured to receive a first detection result of the first welding detection mechanism 200 , a second detection result of the second welding detection mechanism 300 , and a third detection result of the third welding detection mechanism 400 ;

[0040] The control device 600 is also connected to the flipping mechanism 500 , and the control device 600 is also configured to control the flipping structure 500 to flip the battery cell to be inspected when the battery cell to be inspected moves to the first welding inspection mechanism 200 and the second welding inspection mechanism 300 .

[0041] In this solution, it is assumed that the battery cell to be tested includes at least a welded tab. When the battery cell to be tested is tested, the battery cell to be tested is placed on the conveying mechanism 100, and the conveying mechanism 100 transports the battery cell to the location of the designated welding testing mechanism.

[0042] The transmission mechanism 100 may be a conveyor belt, an assembly line device, or the like.

[0043] In this solution, the detection modes of the first welding detection mechanism 200, the second welding detection mechanism 300, and the third welding detection mechanism 400 are set to be different from each other, and the above welding detection devices are set to detect the welding quality of the tab;

[0044] For example, the first welding detection mechanism 200 can perform welding detection based on visual detection, the second welding detection mechanism 300 can perform welding detection based on contact measurement (for measuring resistance, measuring geometric dimensions, etc.), and the third welding detection mechanism 400 can perform welding detection based on tensile detection.

[0045] In this solution, a flipping mechanism 500 is set to flip the battery cell to be tested, so that when the welding detection device needs to detect different positions of the battery cell (pole ear) to be tested and can only detect one position at a time, the position of the battery cell to be tested is adjusted to meet the detection requirements of the welding detection device.

[0046] Exemplarily, in this solution, the flip mechanism 500 may be configured to be in communication connection with the transmission mechanism 100 or to be independently arranged relative to the transmission mechanism 100;

[0047] When the flipping mechanism 500 is in communication connection with the transmission mechanism 100, the flipping mechanism 500 can also be configured to determine whether it is necessary to flip the battery cell to be tested according to the movement of the transmission mechanism 100;

[0048] When the flipping mechanism 500 and the transmission mechanism 100 are independently arranged, the flipping mechanism 500 is configured to flip the battery cell to be inspected according to the control instruction of the control device 600 .

[0049] In this solution, the control device 600 may be an industrial computer, a PLC, etc., wherein the control device 600 is configured to transport the battery cell to be tested to a designated testing station, and when the battery cell to be tested is located at the designated testing station, control the corresponding welding testing device to perform welding testing according to a preset testing procedure;

[0050] In addition, the control device 600 is configured to receive and store the first detection result, the second detection result, and the third detection result, which can be used to determine the evaluation of the welding effect;

[0051] The above detection results can be analyzed in an automated data analysis manner based on a manual method to determine the welding effect.

[0052] This embodiment proposes a welding effect detection device, which includes a first welding detection mechanism, a second welding detection mechanism and a third welding detection mechanism. Through the combined use of multiple testing devices and methods, the problem of detection limitations of a single welding effect evaluation method can be eliminated. Using this device to detect welding effects can prevent false positives and missed releases, reduce production costs, and improve the reliability of LIBs.

[0053] Figure 2 This is another structural block diagram of a welding effect detection device in the embodiment, refer to Figure 2 ,exist Figure 1 Based on the scheme shown, in one possible implementation scheme, the welding effect detection device further includes at least one grasping mechanism 700;

[0054] The control device 600 is also connected to the gripping mechanism 700 , and the control device 600 is also configured to control the gripping mechanism 700 to grip the designated battery cell to be tested.

[0055] In this solution, the gripping mechanism 700 is used to remove the designated battery cell to be tested on the conveying mechanism 100 from the conveying mechanism 100 , wherein the designated battery cell to be tested may be a battery cell that fails to generate a test result or a battery cell with an abnormal test result.

[0056] In this solution, the test result can be judged manually, but when the test result is determined to be abnormal, a preset instruction is manually input to enable the control device 600 to control the grasping mechanism 700 to grasp the designated battery cell to be tested.

[0057] Figure 3 This is another structural block diagram of a welding effect detection device in the embodiment, refer to Figure 3 , based on any of the above solutions, in one possible implementation scheme, the welding effect detection device further includes an ultrasonic welding mechanism 900;

[0058] The control device 600 is also connected to the ultrasonic welding mechanism, and the control device 600 is also configured to control the ultrasonic welding mechanism to weld the tabs of the battery cell.

[0059] In this solution, an ultrasonic welding mechanism 900 is configured to achieve welding of the battery cell tabs, for example, welding the tabs to the connecting pieces provided on the battery cell.

[0060] Furthermore, in the present embodiment, the ultrasonic welding mechanism includes a copper welding mechanism and an aluminum welding mechanism. The copper welding mechanism is used to achieve the welding of copper pole tabs, and the aluminum welding mechanism is used to achieve the welding of aluminum pole tabs.

[0061] refer to Figure 3 In one possible implementation scheme, the welding effect detection device also includes a feeding mechanism 800, which is used to adjust the spatial position of the battery cell and shape the connecting piece of the battery cell.

[0062] In this solution, the feeding mechanism 800 can be specifically configured to: fold the cover plate with the copper / aluminum connecting pieces welded into a T-shape; shape the cover plate so that the copper / aluminum connecting pieces are opened at a certain angle; and place the battery cell in a vertical state to facilitate the integration of the copper / aluminum connecting pieces and then ultrasonic welding of the copper / aluminum tabs.

[0063] In this solution, the specific structure of the feeding mechanism 800 is not limited. For example, the feeding mechanism 800 may include a robotic arm or a shaping component for T-folding and shaping.

[0064] refer to Figure 3 Based on any of the above solutions, in one possible implementation scheme, the welding effect detection device also includes a thickness measuring mechanism 1000, and the control device 600 is also connected to the thickness measuring mechanism 1000.

[0065] In this solution, a thickness measuring mechanism 1000 is provided to detect the thickness of the tab of the battery cell to be tested, wherein the thickness measuring mechanism 1000 can perform thickness measurement by contact (such as caliper measurement) or non-contact (such as ultrasonic measurement), and the result of the thickness measurement can be used as a basis for evaluating the welding effect.

[0066] In this solution, the thickness measuring mechanism 1000 is specifically configured to measure the thickness of the electrode tab after welding.

[0067] On the basis of any of the foregoing solutions, in one possible implementation scheme, the first welding detection mechanism is set to include: a four-probe resistance tester or a four-probe resistance tester, preferably, a four-probe resistance tester is used.

[0068] Furthermore, in a possible implementation scheme, the probes of the four-probe resistance tester are gold-plated spring probes with a constant needle distance.

[0069] On the basis of any of the foregoing solutions, in one possible implementation scheme, the second welding detection mechanism is set to include: a CCD imager or a CMOS imager, and preferably, a CCD imager is used.

[0070] Based on any of the foregoing solutions, in one possible implementation, the third welding detection mechanism is set to include: a tensile tester.

[0071] Figure 4 This is another welding effect detection device result block diagram in the embodiment, refer to Figure 4 Based on any of the above solutions, in one possible implementation scheme, the welding effect detection device includes:

[0072] A conveying mechanism 100, a four-probe resistance tester 201, a CCD imager 301, a tension tester 401, a turning mechanism 500 and a control device 600;

[0073] The four-probe resistance tester 201, the CCD imager 301, and the tension tester 401 are sequentially arranged along the moving direction of the transmission mechanism 100;

[0074] The control device 600 is connected to the transmission mechanism 100 , and the control device 600 is also connected to the four-probe resistance tester 201 , the CCD imager 301 , and the tension tester 401 ;

[0075] It also includes at least one gripping mechanism 700, and the control device 600 is also connected to the gripping mechanism 700;

[0076] It also includes a feeding mechanism 800, which is used to adjust the spatial position of the battery cell and shape the connecting piece of the battery cell;

[0077] It also includes a copper welding mechanism 901 and an aluminum welding mechanism 902. The copper welding mechanism 901 is used to weld the copper pole tabs, and the aluminum welding mechanism 902 is used to weld the aluminum pole tabs.

[0078] Figure 5 It is the working flow chart of the detection device in the embodiment, reference Figure 5In this solution, the working process of the welding effect detection device can be:

[0079] The cover plate with the copper / aluminum connecting piece welded is folded into a T shape, placed on the tray of the feeding mechanism 800, and fed to the ultrasonic welding station to shape the cover plate so that the copper / aluminum connecting piece is opened to a certain angle;

[0080] Control the flip mechanism 500 to make the battery cell in a vertical state, and after integrating the copper / aluminum connecting sheet, control the copper welding mechanism 901 and the aluminum welding mechanism 902 to perform ultrasonic welding of the copper / aluminum tabs and test the thickness of the copper / aluminum tabs after ultrasonic welding;

[0081] Control the flip mechanism 500 to make the battery cell in a horizontal state, control the use of a DC four-probe to test the conductivity of the A side of the tab, and control the use of a CCD imager to test the weld mark area and depth of the A side;

[0082] Control the flipping mechanism 500 to flip the battery cell so that the battery cell is in a horizontal state, use a DC four-probe to test the conductivity of the B side of the tab, and control the CCD imager to test the weld mark area and depth of the B side;

[0083] When the control device 600 determines that the battery cell test is unqualified, it controls the grabbing mechanism to remove the battery cell from the conveying mechanism 100 and send it to the tensile tester 401 for a tab welding tensile test to confirm the effectiveness of the detection by the four-probe resistance tester 201 and the CCD imager;

[0084] If the battery cell passes the inspection, it is transferred to the next process through the conveying mechanism 100 .

[0085] exist Figure 1 On the basis of the beneficial effects of the scheme shown, in this scheme, the DC four-probe method is used to test the conductivity of the weld mark, which can be used as a detection method to evaluate the ultrasonic welding effect. The DC four-probe conductivity measurement method is combined with CCD imaging and tensile testing methods to form a detection device for the ultrasonic welding effect of the tab, which prevents false positives and omissions of poor welding, reduces production costs, and improves the reliability of LIBs. It can avoid the low resolution of CCD imaging for poor welding, which easily causes false positives and omissions; the tensile testing method cannot establish a unified measurement standard between welding tension and welding effect; CCD imaging and tensile testing methods have limitations in evaluating the welding effect between foils and between foils and tabs.

[0086] Figure 6 is a control flow chart of the control device in the embodiment, refer to Figure 6 , exemplarily, in this solution, the control device 600 can be specifically configured as follows:

[0087] After ultrasonic welding of the copper / aluminum tab of the battery cell, the welding energy and tab thickness are fed back to the control device 600, and the control device 600 makes a determination. The abnormal battery cells are discharged at the abnormal discharging station of the grasping mechanism 700;

[0088] After ultrasonic welding of the tab of the battery cell, a DC four-probe test is performed on the conductivity of the tab, and the conductivity value is fed back to the control device 600 for determination. The abnormal battery cells are discharged at the abnormal discharging station of the grasping mechanism 700;

[0089] After ultrasonic welding of the tab of the battery cell, CCD imaging detection is performed on the tab, and the welding mark area and depth are fed back to the control device 600 for determination. The abnormal battery cells are discharged at the abnormal discharging station of the grasping mechanism 700;

[0090] Among them, it is set that if Ea < welding energy < Eb and / or da < tab thickness < db, it is determined that the battery cell is normal. If σ min < conductivity, it is determined that the battery cell is normal. If Sa < welding mark area < Sb and / or Da < depth < Db, it is determined that the battery cell is normal;

[0091] Among them, Ea, Eb, da, db, σ min , Sa, Sb, Da, Db can be determined through experience, simulation tests or calibration tests.

[0092] In this solution, the following method can be used to determine the detection accuracy of the welding effect of the four-probe resistance tester 201:

[0093] Use a low-resistivity tester with a resistivity correction coefficient (test range: 10 -7 ~10 7 Ω), and use a gold-plated spring probe with a constant needle pitch (needle pitch 2 mm);

[0094] The copper tab and the copper connecting piece are ultrasonically welded with given parameters, and the welding energy is adjusted. 10 normal welding battery cells and 10 defective welding battery cells are welded;

[0095] The aluminum tab and the aluminum connecting piece are ultrasonically welded with given parameters, and the welding energy is adjusted. 10 normal welding battery cells and 10 defective welding battery cells are welded;

[0096] Perform surface resistance testing: Input the sample shape (square or circular), sample size and testing position to determine the resistivity correction coefficient (RCF). Use four probes and keep the pressure constant when contacting the test sample to test the surface resistance ρs (Equation 1);

[0097] Equation 1: ρs = V / I × RCF (V is voltage, I is current);

[0098] Conduct volume resistivity test: input sample shape (square or round), sample size and test position to determine resistivity correction factor (RCF), use four probes with constant pressure in contact with the test sample to test surface resistance, link with ultrasonic welding equipment, read the thickness of the tab after ultrasonic welding, and calculate volume resistivity ρV (Equation 2) and conductivity σ (Equation 3);

[0099] Formula 2: ρV = V / I × RCF × t (t represents the sample thickness, unit: mm)

[0100] Formula 3: σ=1 / ρV

[0101] As shown in Table 1, a two-sample t-test was performed on the conductivity of normal copper / aluminum tab ultrasonic welded products and poorly welded battery cells, and the confidence P value was 0.000, indicating that there was a significant difference in the conductivity of normal copper / aluminum tab ultrasonic welded products and poorly welded battery cells. The use of a DC four-probe test to test the conductivity of the weld mark can effectively pick out poorly welded batteries.

[0102] Table 1

[0103]

[0104]

[0105] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A welding effect detection device, characterized in that: include: A conveying mechanism, a first welding detection mechanism, a second welding detection mechanism, a third welding detection mechanism, a turning mechanism and a control device; The first welding detection mechanism, the second welding detection mechanism, and the third welding detection mechanism are arranged in sequence along the moving direction of the conveying mechanism; The control device is connected to the conveying mechanism, and the control device is configured to control the conveying mechanism to transport the battery cell to be tested; The control device is also connected to the first welding detection mechanism, the second welding detection mechanism, and the third welding detection mechanism; The control device is configured to receive a first detection result of the first welding detection mechanism, a second detection result of the second welding detection mechanism, and a third detection result of the third welding detection mechanism; The control device is also connected to the flipping mechanism, and is further configured to control the flipping mechanism to flip the battery cell to be detected when the battery cell to be detected moves to the first welding detection mechanism and the second welding detection mechanism.

2. The welding effect detection device according to claim 1, characterized in that: Also includes at least one grasping mechanism; The control device is also connected to the grasping mechanism, and the control device is also configured to control the grasping mechanism to grasp the designated battery cell to be inspected.

3. The welding effect detection device according to claim 1, characterized in that: Also included is an ultrasonic welding mechanism; The control device is also connected to the ultrasonic welding mechanism, and the control device is also configured to control the ultrasonic welding mechanism to weld the tabs of the battery cell.

4. The welding effect detection device according to claim 3, characterized in that: It also includes a feeding mechanism, which is used to adjust the spatial position of the battery cell and shape the connecting piece of the battery cell.

5. The welding effect detection device according to claim 3, characterized in that: The ultrasonic welding mechanism includes a copper welding mechanism and an aluminum welding mechanism.

6. The welding effect detection device according to claim 1, characterized in that: It also includes a thickness measuring mechanism, and the control device is also connected to the thickness measuring mechanism; The thickness measuring mechanism is used to detect the thickness of the tab of the battery cell to be tested.

7. The welding effect detection device according to claim 1, characterized in that: The first welding detection mechanism includes: a four-probe resistance tester or a two-probe resistance tester.

8. The welding effect detection device according to claim 7, characterized in that: The probes of the four-probe resistance tester are gold-plated spring probes with a constant needle distance.

9. The welding effect detection device according to claim 1, characterized in that: The second welding detection mechanism includes: a CCD imager or a CMOS imager.

10. The welding effect detection device according to claim 1, characterized in that: The third welding detection mechanism includes: a tensile tester.

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