Method for detecting welding state of outer tab of capacitor

Abstract

The invention discloses a method for detecting the welding state of an outer tab of a capacitor, and the method comprises the steps: S1, welding resistance detection: detecting the welding resistance between a plurality of tab test points on the outer tab of the capacitor to be tested and cover plate test points on a capacitor cover plate, and defining the welding resistance as a plurality of test point welding resistance; s2, test point welding quality judgment: judging the welding quality of a welding area corresponding to each tab test point according to the test point welding resistance of each tab test point and a preset resistance threshold value; and S3, overall welding quality judgment of the outer tabs: when all the tab test points have no poor welding problem, judging that the welding quality of the outer tabs on the capacitor is qualified, otherwise, judging that the welding quality of the outer tabs on the capacitor is unqualified. According to the invention, the welding quality of the outer tab on the capacitor can be efficiently and accurately judged, the working efficiency is improved, and the production quality of the capacitor is ensured. And the specific position of the welding defect can be accurately positioned, and reworking and maintenance are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of capacitor and supercapacitor manufacturing, and in particular to a method for detecting the welding state of an outer pole ear of a capacitor. Background Art

[0002] Supercapacitor batteries are widely used in electric vehicles and military fields due to their high power density, light weight, fast charging, no memory effect, and long service life. Therefore, people are currently demanding higher and higher quality performance of supercapacitors.

[0003] In the production process of supercapacitors, external ear welding (that is, welding the external ear to the cover of the capacitor) is one of the key processes. The external ear is the only component connecting the capacitor monomer and the PCB board (i.e. integrated circuit board). It mainly plays the role of conducting current and is required to be fixed on the cover of the capacitor by welding. Therefore, the welding quality of the external ear on the capacitor directly affects the performance and safety of the capacitor module and even the entire user terminal.

[0004] At present, the common method for detecting the welding quality of the capacitor outer ear is mainly: manual visual inspection. Manual visual inspection is not only inefficient, but also easily affected by subjective factors of the staff, and cannot accurately judge the welding quality of the capacitor outer ear.

[0005] Therefore, it is urgent to develop a technology that can solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide a method for detecting the welding state of a capacitor outer tab in view of the technical defects in the prior art.

[0007] To this end, the present invention provides a method for detecting the welding state of a capacitor outer tab, comprising the following steps:

[0008] Step S1, welding resistance detection: detecting welding resistances between a plurality of tab test points on the outer tab of the capacitor to be tested and a cover plate test point on the capacitor cover plate, and defining the welding resistances as a plurality of test point welding resistances;

[0009] Each of the tab test points is: a position point distributed on the external tab terminal included in the external tab;

[0010] The cover plate test point is the position point on the top surface of the capacitor cover plate;

[0011] Step S2, test point welding quality determination: judging the welding quality of the welding area corresponding to each tab test point according to the test point welding resistance of each tab test point and a preset resistance threshold;

[0012] The welding area corresponding to each tab test point is the welding area between the outer tab terminal where each tab test point is located and the capacitor cover plate;

[0013] Among them, for any pole ear test point, if the test point welding resistance it has is greater than the preset resistance threshold, it is judged that the welding area corresponding to the pole ear test point has a poor welding problem, that is, the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is unqualified; otherwise, it is judged that there is no poor welding problem in the welding area corresponding to the pole ear test point, and the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is qualified;

[0014] Step S3, judging the overall welding quality of the outer pole lugs: when there is no poor welding problem at all the pole lug test points, it is judged that the welding quality of the outer pole lugs on the capacitor is qualified; otherwise, it is judged that the welding quality of the outer pole lugs on the capacitor is unqualified.

[0015] It can be seen from the technical solution provided by the present invention that, compared with the prior art, the present invention provides a method for detecting the welding status of the outer pole ear of a capacitor, which is scientifically designed, can efficiently and accurately judge the welding quality of the outer pole ear on the capacitor, improve work efficiency, and ensure the production quality of the capacitor, and has great practical significance.

[0016] In addition, by applying the present invention, the specific position of the welding defect can be accurately located, which is convenient for rework and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a basic working flow chart of a method for detecting the welding state of a capacitor outer tab provided by the present invention;

[0018] Figure 2 The present invention provides a method for detecting the welding state of a capacitor outer pole ear. In a specific embodiment, the outer pole ear detected is an appearance diagram, and the outer pole ear includes three terminals;

[0019] In the figure, 1-external pole ear, 11-first external pole ear terminal, 12-second external pole ear terminal, 13-external pole ear terminal;

[0020] Figure 3 It is a method for detecting the welding state of the outer pole ear of a capacitor provided by the present invention, and an appearance diagram of a capacitor cover plate detected in a specific embodiment;

[0021] In the figure, 2-capacitor cover, 21-first cover slot (i.e., the outer pole ear slot into which the first outer pole ear terminal is inserted), 22-second cover slot (i.e., the outer pole ear slot into which the second outer pole ear terminal is inserted), 23-third cover slot (i.e., the outer pole ear slot into which the third outer pole ear terminal is inserted);

[0022] Figure 4 The present invention provides a method for detecting the welding state of the capacitor outer pole ear. In a specific embodiment, the welding state of the outer pole ear and the capacitor cover plate to be detected is shown in FIG.

[0023] In the figure, W1-the welding position of the first outer pole ear terminal and the capacitor cover; W2-the welding position of the second outer pole ear terminal and the capacitor cover; W3-the welding position of the third outer pole ear terminal and the capacitor cover;

[0024] Figure 5 A method for detecting the welding state of an outer pole ear of a capacitor provided by the present invention is a schematic diagram of a resistance measurement position in a specific embodiment;

[0025] In the figure, line segment DA represents the resistance (DA) between point A on the outer lug and point D on the capacitor cover;

[0026] Line segment EB represents the welding resistance between point B on the outer ear and point E on the capacitor cover;

[0027] Line segment FC represents the resistance (FC) between point C on the outer lug and point F on the capacitor cover;

[0028] Figure 6 It is a schematic diagram comparing the resistance values ​​of the outer pole ear terminal and the capacitor cover plate in the welded state and the unwelded state in a specific embodiment. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, 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" 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.

[0031] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0032] 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 one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0034] See also Figures 1 to 6 The present invention provides a method for detecting the welding state of a capacitor outer ear, comprising the following steps:

[0035] Step S1, welding resistance detection: detecting welding resistance between a plurality of tab test points on the outer tab 1 of the capacitor to be tested and a cover plate test point on the capacitor cover plate 2, and defining the welding resistance as a plurality of test point welding resistances;

[0036] Each of the tab test points is: a position point distributed on the external tab terminal included in the external tab 1;

[0037] The cover plate test point is a position point on the top surface of the capacitor cover plate 2;

[0038] In step S1, it should be noted that the cover plate test point is, for example, any position point on the capacitor cover plate 2, or any position point on the capacitor cover plate 2 that is adjacent to the tab test point; wherein the cover plate test point is preferably: any position point on the capacitor cover plate 2 whose shortest current conduction distance to the tab test point is equal to a preset distance value;

[0039] The shortest current conduction distance between the position point and the tab test point is equal to the minimum value of the sum of the current conduction straight-line distance on the capacitor cover plate 2 and the current conduction straight-line distance on the outer tab terminal of the outer tab 1 when the current is conducted between the position point and the tab test point;

[0040] The preset distance value may be equal to the sum of a preset ratio (for example, one third) of the radius of the capacitor cover plate 2 and a vertical height of the outer tab terminal portion where the tab test point is located.

[0041] Step S2, test point welding quality determination: judging the welding quality of the welding area corresponding to each tab test point according to the test point welding resistance of each tab test point and a preset resistance threshold;

[0042] The welding area corresponding to each tab test point is the welding area between the outer tab terminal where each tab test point is located and the capacitor cover plate 2;

[0043] Among them, for any pole ear test point, if the test point welding resistance it has is greater than the preset resistance threshold, it is judged that the welding area corresponding to the pole ear test point has a poor welding problem, that is, the welding quality of the welding area corresponding to the pole ear test point is unqualified (that is, the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is unqualified); otherwise, it is judged that there is no poor welding problem in the welding area corresponding to the pole ear test point, that is, the welding quality of the welding area corresponding to the pole ear test point is qualified (that is, the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is qualified);

[0044] Step S3, judging the overall welding quality of the outer pole lug: when there is no poor welding problem at all the pole lug test points, it is judged that the welding quality of the outer pole lug on the capacitor is qualified; otherwise (that is, as long as the welding quality of the welding area corresponding to one pole lug test point is unqualified), it is judged that the welding quality of the outer pole lug on the capacitor is unqualified.

[0045] It should be noted that when a welding area corresponding to one or more test points of a capacitor has a poor welding problem, the capacitor needs to be reworked, or the capacitor with poor welding needs to be removed and scrapped.

[0046] In step S1, for specific implementation, see Figure 2 As shown, the external pole lug 1 includes a first external pole lug terminal 11, a second external pole lug terminal 12 and a third external pole lug terminal 13;

[0047] The rear ends of the first external tab terminal 11 and the second external tab terminal 12 are connected to the left and right sides of the lower part of the third external tab terminal 13 respectively;

[0048] The first external tab terminal 11 and the second external tab terminal 12 are symmetrically distributed.

[0049] Each of the tab test points is: a position point distributed on the first tab terminal 11, the second tab terminal 12 and the third tab terminal 13 included in the tab 11;

[0050] In a specific implementation, the first external tab terminal 11 , the second external tab terminal 12 and the third external tab terminal 13 are integrally formed.

[0051] In a specific implementation, the multiple tab test points on the outer tab 1 of the capacitor include three tab test points;

[0052] The three tab test points are: any position point on the top of the first external tab terminal 11, any position point on the top of the second external tab terminal 12, and any position point on the top of the third external tab terminal 13;

[0053] Further, preferably, a first external welding assembly support boss 1102 is respectively provided at the front and rear ends of the top of the first external tab terminal 11 to protrude upwards;

[0054] A second external welding assembly support boss 1202 is respectively provided at the front and rear ends of the top of the second external tab terminal 12 to protrude upwards;

[0055] The lug test point on the first external lug terminal 11 and the lug test point on the second external lug terminal 12 are respectively located at any position point (specifically the center point) on the top surface of the first external welding support positioning boss 1102 and any position point (specifically the center point) on the top surface of the second external welding assembly support boss 1202.

[0056] Further, preferably, the top of the third external tab terminal 13 is provided with three welding assembly pins 1302 protruding upward and distributed at equal intervals;

[0057] The tab test point on the third external tab terminal 13 is located at any position point (specifically, the center point) on the top surface of the welding assembly pin 1302 .

[0058] Furthermore, the top surface of the first external welding assembly support boss 1102 and the top surface of the second external welding assembly support boss 1202 are on the same plane, both of which are horizontal planes.

[0059] It should be noted that the three welding assembly pins 1302 on the top of the third external pole ear terminal 13 are used to insert into the printed circuit board PCB to be installed and perform welding operations with the welding points on the PCB board (i.e., three welding insertion slots, which are used to insert three welding assembly pins 1302); the top surface of the first external welding assembly support boss 1102 and the second external welding assembly support boss 1202 serve as support points between the capacitor and the PCB board.

[0060] In step S2, in specific implementation, the welding area between the external pole lug terminal where each test point is located and the capacitor cover is specifically: the welding position between the lower part of the external pole lug terminal where each test point is located and the top surface of the capacitor cover 2, preferably: the welding position between the positioning pin at the lower part of the external pole lug terminal where each test point is located and the slot on the capacitor cover 2.

[0061] For specific implementation, see Figure 4 As shown, the welding position between the lower part of the external tab terminal and the top surface of the capacitor cover plate 2 where each test point is located includes the welding position between the first external tab terminal 11 and the top surface of the capacitor cover plate 2, the welding position between the second external tab terminal 12 and the top surface of the capacitor cover plate 2, and the welding position between the lower part of the third external tab terminal 13 and the top surface of the capacitor cover plate 2, that is, these three positions can be included, such as Figure 4 There are three welding positions shown: W1, W2 and W3.

[0062] Further, preferably, see Figure 2 , Figure 3 As shown, the lower parts of the first external tab terminal 11, the second external tab terminal 12 and the third external tab terminal 13 respectively have a first positioning pin 1101, a second positioning pin 1201 and a third positioning pin 1301;

[0063] The top of the capacitor cover plate 2 is provided with a concave first cover plate slot 21, a second cover plate slot 22 and a third cover plate slot 23 at positions corresponding to the first positioning pin 1101, the second positioning pin 1201 and the third positioning pin 1301, respectively;

[0064] The first cover plate slot 21, the second cover plate slot 22 and the third cover plate slot 23 are used to insert the first positioning pin 1101, the second positioning pin 1201 and the third positioning pin 1301 respectively;

[0065] The welding positions between the positioning pins at the lower part of the external pole lug terminal and the slots on the capacitor cover 2 preferably include: the welding position between the first positioning pin 1101 of the first external pole lug terminal 11 and the first cover slot 21, the welding position between the second positioning pin 1201 of the second external pole lug terminal 12 and the second cover slot 22, and the welding position between the third positioning pin 1301 of the third external pole lug terminal 13 and the third cover slot 23.

[0066] It should be noted that the welding position between the first positioning pin 1101 and the first cover slot 21 is specifically: after the first positioning pin 1101 of the first external tab terminal 11 is inserted into the first cover slot, the top surface of the capacitor cover 2 contacts the upper end portion of the first positioning pin 1101 exposed in the first cover slot 21;

[0067] The welding position between the second positioning pin 1201 of the second external tab terminal 12 and the second cover plate slot 22 is specifically: after the second positioning pin 1201 of the second external tab terminal 12 is inserted into the second cover plate slot 22, the top surface of the capacitor cover plate 2 contacts the second positioning pin 1201 exposed in the upper end portion of the second cover plate slot 22;

[0068] The welding position between the third positioning pin 1301 of the third external tab terminal 13 and the third cover slot 23 is specifically: after the third positioning pin 1301 of the third external tab terminal 13 is inserted into the third cover slot 23, the top surface of the capacitor cover 2 contacts the upper end portion of the third positioning pin 1301 exposed in the third cover slot 23;

[0069] Furthermore, the shapes and sizes of the first cover plate groove 21 , the second cover plate groove 22 and the third cover plate groove 23 correspond to and match the shapes and sizes of the first positioning pin 1101 , the second positioning pin 1201 and the third positioning pin 1301 , respectively.

[0070] In step S1, in a specific implementation, the cover plate test points preferably include: a first cover plate test position point, a second cover plate test position point and a third cover plate test position point;

[0071] The first cover plate test position point is: any position point on the capacitor cover plate 2, where the shortest current conduction distance between the capacitor cover plate 2 and any position point on the top surface of the first external welding support positioning boss 1102 (i.e., the tab test point, which is the center point) is equal to the preset distance value;

[0072] The second cover plate test position point is: any position point on the capacitor cover plate 2 and any position point on the top surface of the second external welding assembly support boss 1202 (i.e., the tab test point, which is the center point) where the shortest current conduction distance is equal to the preset distance value;

[0073] It should be noted that the first external pole lug terminal 11 or the second external pole lug terminal 12 has the same shape and size; the preset distance values ​​corresponding to the first cover plate test position point and the second cover plate test position point are equal, which can be: equal to: the sum of a preset proportion (for example, one third) of the radius of the capacitor cover plate 2 and the vertical height of the external pole lug terminal part (the first external pole lug terminal 11 or the second external pole lug terminal 12) where the pole lug test point is located.

[0074] The third cover plate test position point is any position point on the capacitor cover plate 2 and any position point on the top surface of the welding assembly pin 1302 of the third external tab terminal 13 (i.e., the tab test point, which is the center point) where the shortest current conduction distance is equal to the preset distance value;

[0075] The preset distance value corresponding to the third cover plate test position point can be specifically equal to the sum of a preset ratio (for example, one third) of the radius of the capacitor cover plate 2 and the vertical height of the outer tab terminal part (the third outer tab terminal 13) where the tab test point is located.

[0076] In specific implementation, it is preferred that the preset distance values ​​corresponding to the first cover plate test position point, the second cover plate test position point and the third cover plate test position point are all equal. At this time, since the height of the third external pole ear terminal 13 exposed from the top surface of the capacitor cover plate 2 is higher than the height of the first external pole ear terminal 11 or the second external pole ear terminal 12 exposed from the top surface of the capacitor cover plate 2, for this reason, when determining the third cover plate test position point according to the preset distance value corresponding to the third cover plate test position point, it is necessary to adjust the preset ratio of the radius of the capacitor cover plate 2 included in the preset distance value corresponding to the third cover plate test position point accordingly (reduced, the ratio must be smaller than the ratio of the radius of the capacitor cover plate 2 corresponding to the first cover plate test position point and the second cover plate test position point) to meet the conditions.

[0077] In step S1, for specific implementation, see Figure 5 As shown, multiple test points are welded with resistors, specifically including the following resistors:

[0078] The welding resistance between the tab test point A on the first tab terminal 11 of the tab 1 and the cover test point D on the capacitor cover 2 represents: the welding resistance between the first tab terminal 11 and the capacitor cover 2;

[0079] The welding resistance between the tab test point B on the second tab terminal 12 of the tab 1 and the cover test point E on the capacitor cover 2 represents: the welding resistance between the second tab terminal 12 and the capacitor cover 2;

[0080] And, the welding resistance between the tab test point C on the third tab terminal 13 of the external tab 1 and the cover test point F on the capacitor cover 2 represents: the welding resistance between the third tab terminal 13 and the capacitor cover 2 .

[0081] In step S2, a resistance threshold is preset, preferably equal to the average value of welding resistances of a plurality of capacitors with known qualified outer pole ear welding quality in advance, and the average value of welding resistance of each capacitor is equal to the average value of welding resistances between a plurality of pole ear test points on its outer pole ear 1 and corresponding cover plate test points on the capacitor cover plate 2;

[0082] It should be noted that the positions of multiple lug test points of the capacitor with qualified outer lug welding quality and the cover test points on the capacitor cover 2 are exactly the same as the positions of multiple lug test points of the capacitor to be tested and the cover test points on the capacitor cover 2 in step S1, and the capacitor with qualified outer lug welding quality and the capacitor to be tested are capacitors of the same specifications and models.

[0083] In the present invention, the preset resistance threshold can be set according to welding process parameters and capacitor model.

[0084] In step S2, in specific implementation, for any tab test point, when it is determined that the welding area corresponding to the tab test point has a poor welding problem, the following steps are also included (i.e., judging the defect type according to the size and change trend of the resistance value):

[0085] Step S21, if the test point welding resistance of the tab test point is much greater than the resistance threshold, it is determined that the welding area corresponding to the tab test point is not actually welded;

[0086] The test point welding resistance is much greater than the resistance threshold, which means that: the resistance value of the test point welding resistance is greater than or equal to a preset multiple of the resistance threshold (for example, five times the resistance threshold);

[0087] Step S22, if the test point welding resistance of the tab test point is slightly greater than the resistance threshold, it is determined that the welding area corresponding to the tab test point has actually been welded, but there are defects in the welding (for example, there are defects in the welding, such as cold welding, false welding or incomplete welding);

[0088] The test point welding resistance is slightly greater than the resistance threshold, which means that: the resistance value of the test point welding resistance is greater than the resistance threshold and less than a preset multiple of the resistance threshold (for example, five times the resistance threshold);

[0089] In step S21 and step S22, it should be noted that the preset multiple can be adjusted according to specific experimental data and is not limited to five times. It can be adjusted accordingly according to the different resistivities of the external pole ears made of different types of materials and the different resistivities of the capacitor cover plates made of different types of materials.

[0090] In the present invention, after step S3, the following steps are also included:

[0091] Step S4, obtaining the identification information of the capacitor to be tested and storing it;

[0092] Step S5, pre-store the corresponding relationship between the identification information of each capacitor and the judgment result of the welding quality of the outer electrode ear of the capacitor, and upload it to the capacitor information tracing system (ie, an external computer system) in real time.

[0093] In step S4, in a specific implementation, a barcode scanner is used to scan the identity identification QR code on the bottom of the capacitor shell to obtain the unique identity identification information of the capacitor.

[0094] It should be noted that, for the present invention, the test data can be bound to the QR code information of the capacitor and uploaded to the traceability system to achieve real-time management of production data.

[0095] In the present invention, in a specific implementation, the tester used to test the welding resistance of the test point is a tester with mature existing technology and has been widely used, for example, a high-precision four-wire resistance tester can be used.

[0096] In order to more clearly understand the technical solution of the present invention, the technical solution of the present invention is described below through specific embodiments.

[0097] Example

[0098] The present invention provides a method for detecting the welding state of a capacitor outer tab, and the specific detection process is as follows:

[0099] Step 1: Prepare samples;

[0100] 1. Prepare sample 1, in which only the first external tab terminal 11 is welded to the capacitor cover plate 2, and the second external tab terminal 12 and the third external tab terminal 13 are not welded;

[0101] 2. Prepare sample 2, in which only the second external tab terminal 12 is welded to the capacitor cover plate 2, and the external tab terminal A is not welded to the third external tab terminal 13;

[0102] 3. Prepare sample 3, in which only the third external tab terminal 13 is welded to the capacitor cover plate 2, and the first external tab terminal 11 and the second external tab terminal 12 are not welded;

[0103] 4. Prepare sample 4, in which only the second external tab terminal 12 and the third external tab terminal 13 are welded to the capacitor cover plate 2, and the first external tab terminal 11 is not welded;

[0104] 5. Prepare sample 5, in which only the first external tab terminal 11 and the third external tab terminal 13 are welded to the capacitor cover plate 2, and the second external tab terminal 12 is not welded;

[0105] 6. Prepare sample 6, in which only the first external tab terminal 11 and the second external tab terminal 12 are welded to the capacitor cover plate 2, and the third external tab terminal 13 is not welded;

[0106] 7. Prepare sample 7, in which the first external tab terminal 11, the second external tab terminal 12 and the third external tab terminal 13 are all welded to the capacitor cover plate 2;

[0107] 8. Prepare sample 8, in which the first external tab terminal 11 , the second external tab terminal 12 and the third external tab terminal 13 are not welded to the capacitor cover plate 2 .

[0108] Step 2: Data collection;

[0109] 1. See Figure 5As shown, a four-wire high-precision resistance tester is used to measure the resistance values ​​between point D and point A, point E and point B, and point F and point C, respectively, and the resistance values ​​DA, EB, and FC at the three positions are obtained;

[0110] Among them, point A and point B are the tab test points on the first external tab terminal 11 and the tab test points on the second external tab terminal 12, respectively, specifically the center point of the top surface of the first external welding support positioning boss 1102 and the center point of the top surface of the second external welding assembly support boss 1202;

[0111] Point C is a tab test point on the third external tab terminal 13, and is located at the center point of the top surface of the welding assembly pin 1302;

[0112] 2. Summarize the data and output the comparison chart, see Figure 6 As shown;

[0113] Figure 6 For the above samples, the area shown in A1 is the distribution of welding resistance data between point A and point D when the welding area corresponding to the tab test point A of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) has been welded;

[0114] For the above samples, the area shown in A2 is the distribution of welding resistance data between point A and point D when the welding area corresponding to the tab test point A of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) is not welded;

[0115] For the above samples, the area shown in B1 is the distribution of welding resistance data between point B and point E when the welding area corresponding to the tab test point B of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) has been welded;

[0116] For the above samples, the area shown in B2 is the distribution of welding resistance data between point B and point E when the welding area corresponding to the tab test point B of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) is not welded;

[0117] For the above samples, the area shown by C1 is the distribution of welding resistance data between point C and point F when the welding area corresponding to the tab test point C of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) has been welded;

[0118] For the above samples, the area shown by C2 is the distribution of welding resistance data between point C and point F when the welding area corresponding to the tab test point C of the sample (i.e., the welding area between the outer tab terminal and the capacitor cover plate 2) is not welded.

[0119] Step 3: Data analysis;

[0120] Depend on Figure 6 It can be seen that the resistance value between the welded outer lug terminal and the capacitor cover is much smaller than the resistance value between the unwelded outer lug terminal and the capacitor cover.

[0121] Step 4: Determine the resistance threshold;

[0122] In a specific implementation, the method for obtaining the preset resistance threshold may include the following operations:

[0123] In the first operation, a plurality of sample combinations (the first sample combination to the sixth sample combination) of the same quantity are prepared in advance;

[0124] The first sample combination includes a plurality of (for example, 40) samples in which the first outer tab terminals 11 have been welded to the capacitor cover plate 2 (ie, sample 1);

[0125] A second sample combination includes a plurality of (for example, 40) samples in which the first outer tab terminals 11 are not welded to the capacitor cover plate 2 (ie, sample 4);

[0126] A third sample combination includes a plurality of (for example, 40) samples in which the second outer tab terminals 12 have been welded to the capacitor cover plate 2 (ie, sample 2);

[0127] A fourth sample combination includes a plurality of (for example, 40) samples in which the second outer tab terminals 12 are not welded to the capacitor cover plate 2 (ie, sample 5);

[0128] A fifth sample combination includes a plurality of (for example, 40) samples in which the third outer tab terminals 13 have been welded to the capacitor cover plate 2 (ie, sample 3);

[0129] A sixth sample combination, including a plurality of (for example, 40) samples in which the third outer tab terminals 13 are not welded to the capacitor cover plate 2 (ie, sample 6);

[0130] In the second step, for the first sample combination, the welding resistance between the tab test point A on the first external tab terminal 11 of each sample and the cover plate test point D on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point A and point D when welding;

[0131] For the second sample combination, the welding resistance between the tab test point A on the first external tab terminal 11 of each sample and the cover plate test point D on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point A and point D when not welded;

[0132] For the third sample combination, the welding resistance between the tab test point B on the second outer tab terminal 12 of each sample and the cover plate test point E on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point B and point E when welding;

[0133] For the fourth sample combination, the welding resistance between the tab test point B on the second outer tab terminal 12 of each sample and the cover plate test point E on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point B and point E when not welded;

[0134] For the fifth sample combination, the welding resistance between the tab test point C on the third external tab terminal 13 of each sample and the cover plate test point F on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point C and point F when welded;

[0135] For the sixth sample combination, the welding resistance between the tab test point C on the third external tab terminal 13 of each sample and the cover plate test point E on the capacitor cover plate 2 is measured respectively, and then after summing, it is divided by the total number of samples (for example, 40) to obtain the average value of the welding resistance between point C and point F when not welded;

[0136] The third step is to sum the average values ​​of the welding resistance between the tab test point and the cover plate test point of the three combinations of the first sample combination, the second sample combination and the third sample combination, and then perform an averaging operation to obtain the average value of the welding resistance between the tab test point and the cover plate test point of the welded (i.e., the welding quality is qualified) capacitor, which is defined as the average value of the welding resistance of the welded capacitor, and the average value of the welding resistance of the welded capacitor is the preset resistance threshold;

[0137] In specific implementation, it should be noted that the average value of the welding resistance between the tab test point and the cover plate test point of the three combinations of the second sample combination, the fourth sample combination and the sixth sample combination is summed and then averaged to obtain the average value of the welding resistance between the tab test point and the cover plate test point of the capacitor that is not welded (welding quality is unqualified), and it is defined as the average value of the welding resistance of the unwelded capacitor;

[0138] The preset multiple resistance threshold value in step S21 and step S22 is a natural number, and the natural number is greater than or equal to the quotient obtained by dividing the average value of the welding resistance of the unsoldered capacitor by the average value of the welding resistance of the welded capacitor (the preset resistance threshold value) (when the quotient is a natural number, it can be equal to or greater than, and when the quotient is a decimal, it is just greater than);

[0139] In the present invention, based on the data of this embodiment and considering the overall credibility, the preset resistance threshold between the external lug terminal and the capacitor cover can be set as: the average resistance value of the three groups of welded sample combinations + 5×standard deviation = 0.10mΩ, that is, when the resistance value between an external lug terminal and the capacitor cover is greater than the preset resistance threshold (for example, 0.10mΩ), the welding between the external lug terminal and the capacitor cover is judged to be unqualified, that is, it is a defective product.

[0140] In specific implementation, the 6 groups of samples obtained above (40 values ​​in each group) can be used to draw a "box plot" using professional statistical software (minitab) to obtain Figure 6 , Figure 6 The three box areas in the middle (A2, B2, C2 in the figure) represent the three sets of resistance value data without welding, and the three box areas below (A1, B1, C1) represent the three sets of resistance value data after welding. The horizontal line in each box area is their average value, and it is marked with a number next to it.

[0141] It should be noted that in statistics, the standard deviation is expressed as the square root of the average of the squares of the deviations between each data point and the average value of the group to which the data point belongs, reflecting the degree of dispersion of the group of data. It can be obtained by calculation, and here it is calculated by Minitab software.

[0142] It should be noted that in order for the sample data (40) to accurately cover all the overall data values, according to some statistical theorems, specifically:

[0143] ±1 standard deviation from the mean covers approximately 68.27% of the data. ±2 standard deviations from the mean covers approximately 95.45% of the data. ±3 standard deviations from the mean covers approximately 99.73% of the data. ±4 standard deviations from the mean covers approximately 99.99366% of the data. ±5 standard deviations from the mean covers almost all of the data, except for extreme outliers. The probability of data outside ±5 standard deviations from the mean is very small, close to zero. In fact, this range can be considered a 100% confidence level, because it is almost impossible to observe data points outside this range in practice.

[0144] Therefore, based on Figure 6 According to the detection data shown, in the embodiment of the present invention, the preset resistance threshold value can be set as: the average resistance value of the three groups of welded samples + 5×standard deviation = 0.10 mΩ.

[0145] Compared with the prior art, the present invention has the following beneficial technical effects:

[0146] 1. Efficient and rapid: It can quickly judge the welding quality between the outer ear on the capacitor and the capacitor cover, and find defects in time.

[0147] 2. Accurate positioning: It can accurately locate the position of welding defects, which is convenient for rework and repair.

[0148] 3. Data management: It can realize real-time management of production data and improve production efficiency and quality control level.

[0149] 4. High accuracy: reduce manual intervention, reduce labor intensity and improve production efficiency.

[0150] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting the welding state of a capacitor outer tab, characterized in that: The following steps are involved: Step S1, welding resistance detection: detecting welding resistances between a plurality of tab test points on an outer tab (1) of a capacitor to be tested and a cover plate test point on a capacitor cover plate (2), and defining the welding resistances as a plurality of test point welding resistances; Each of the tab test points is: a position point distributed on the external tab terminal included in the external tab (1); The cover plate test point is a position point on the top surface of the capacitor cover plate (2); Step S2, test point welding quality determination: judging the welding quality of the welding area corresponding to each tab test point according to the test point welding resistance of each tab test point and a preset resistance threshold; The welding area corresponding to each tab test point is the welding area between the outer tab terminal where each tab test point is located and the capacitor cover plate (2); Among them, for any pole ear test point, if the test point welding resistance it has is greater than the preset resistance threshold, it is judged that the welding area corresponding to the pole ear test point has a poor welding problem, that is, the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is unqualified; otherwise, it is judged that there is no poor welding problem in the welding area corresponding to the pole ear test point, and the welding between the outer pole ear terminal where the pole ear test point is located and the capacitor cover is qualified; Step S3, judging the overall welding quality of the outer pole lugs: when there is no poor welding problem at all the pole lug test points, it is judged that the welding quality of the outer pole lugs on the capacitor is qualified; otherwise, it is judged that the welding quality of the outer pole lugs on the capacitor is unqualified.

2. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S1, the external tab 1 includes a first external tab terminal (11), a second external tab terminal (12) and a third external tab terminal (13); The rear ends of the first external tab terminal (11) and the second external tab terminal (12) are respectively connected to the left and right sides of the lower part of the third external tab terminal (13); The first external pole lug terminal (11) and the second external pole lug terminal (12) are symmetrically distributed on the left and right sides; Each of the tab test points is a position point distributed on a first tab terminal (11), a second tab terminal (12) and a third tab terminal (13) included in the tab (11).

3. The method for detecting the welding state of the capacitor outer tab according to claim 2, characterized in that: A plurality of tab test points on an outer tab (1) of the capacitor, including three tab test points; The three tab test points are: any position point on the top of the first external tab terminal (11), any position point on the top of the second external tab terminal (12), and any position point on the top of the third external tab terminal (13).

4. The method for detecting the welding state of the capacitor outer tab according to claim 3, characterized in that: A first external welding assembly support boss (1102) is respectively provided at the front and rear ends of the top of the first external tab terminal (11) to protrude upwards; A second external welding assembly support boss (1202) is respectively provided at the front and rear ends of the top of the second external tab terminal (12) to protrude upwards; The tab test point on the first external tab terminal (11) and the tab test point on the second external tab terminal (12) are respectively located at the center point of the top surface of the first external welding support positioning boss (1102) and the center point of the top surface of the second external welding assembly support boss (1202); The top of the third external tab terminal (13) is provided with three welding assembly pins (1302) protruding upward and distributed at equal intervals; The tab test point on the third external tab terminal (13) is located at the center point of the top surface of the welding assembly pin (1302).

5. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S2, the welding area between the external tab terminal and the capacitor cover plate where each test point is located is: the welding position between the lower part of the external tab terminal where each test point is located and the top surface of the capacitor cover plate (2).

6. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S2, the welding area between the external tab terminal where each test point is located and the capacitor cover plate is the welding position between the positioning pin at the lower part of the external tab terminal where each test point is located and the slot on the capacitor cover plate (2); The lower parts of the first external pole lug terminal (11), the second external pole lug terminal (12) and the third external pole lug terminal (13) respectively have a first positioning pin (1101), a second positioning pin (1201) and a third positioning pin (1301); A first cover plate slot (21), a second cover plate slot (22) and a third cover plate slot (23) are respectively provided at the top of the capacitor cover plate (2) at positions corresponding to the first positioning pin (1101), the second positioning pin (1201) and the third positioning pin (1301); The first cover plate slot (21), the second cover plate slot (22) and the third cover plate slot (23) are used to insert the first positioning pin (1101), the second positioning pin (1201) and the third positioning pin (1301), respectively; The welding positions between the positioning pins at the lower part of the external pole lug terminal and the slots on the capacitor cover plate (2) include: the welding position between the first positioning pin (1101) of the first external pole lug terminal (11) and the first cover plate slot (21), the welding position between the second positioning pin (1201) of the second external pole lug terminal (12) and the second cover plate slot (22), and the welding position between the third positioning pin (1301) of the third external pole lug terminal (13) and the third cover plate slot (23).

7. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S1, the cover plate test point is any position point on the capacitor cover plate (2) whose shortest current conduction distance to the tab test point is equal to a preset distance value; The shortest current conduction distance between the position point and the tab test point is equal to the minimum value of the sum of the current conduction straight-line distance on the capacitor cover plate (2) and the current conduction straight-line distance on the outer tab terminal of the outer tab (1) when the current is conducted between the position point and the tab test point; The preset distance value is equal to the sum of a preset ratio of the radius of the capacitor cover plate (2) and a vertical height of the outer tab terminal portion where the tab test point is located.

8. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S1, the cover plate test points include: a first cover plate test position point, a second cover plate test position point and a third cover plate test position point; The first cover plate test position point is any position point on the capacitor cover plate (2) where the shortest current conduction distance between the capacitor cover plate (2) and the center point of the top surface of the first external welding support positioning boss (1102) is equal to a preset distance value; The second cover plate test position point is: any position point on the capacitor cover plate (2) where the shortest current conduction distance between the center points of the top surface of the second external welding assembly support boss (1202) is equal to a preset distance value; The preset distance values ​​corresponding to the first cover plate test position point, the second cover plate test position point and the third cover plate test position point are all equal.

9. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: In step S1, multiple test points are welded with resistors, specifically including the following resistors: The welding resistance between the tab test point A on the first tab terminal (11) of the tab (1) and the cover test point D on the capacitor cover (2) represents: the welding resistance between the first tab terminal (11) and the capacitor cover (2); The welding resistance between the tab test point B on the second tab terminal (12) of the tab (1) and the cover test point E on the capacitor cover (2) represents: the welding resistance between the second tab terminal (12) and the capacitor cover (2); And, the welding resistance between the tab test point C on the third tab terminal (13) of the tab (1) and the cover test point F on the capacitor cover (2) represents: the welding resistance between the third tab terminal (13) and the capacitor cover (2); In step S2, a resistance threshold is preset, which is equal to the average value of the welding resistances of a plurality of capacitors whose outer pole lug welding quality is known in advance to be qualified, and the average value of the welding resistance of each capacitor is equal to the average value of the welding resistances between a plurality of pole lug test points on its outer pole lug (1) and corresponding cover plate test points on the capacitor cover plate (2).

10. The method for detecting the welding state of the capacitor outer tab according to claim 1, characterized in that: After step S3, the method further includes the following steps: Step S4, obtaining the identification information of the capacitor to be tested and storing it; Step S5, pre-storing the corresponding relationship between the identification information of each capacitor and the judgment result of the welding quality of the outer pole ear of the capacitor, and uploading it to the capacitor information tracing system in real time; In step S4, a barcode scanner is used to scan the identity identification QR code on the bottom of the capacitor shell to obtain the unique identity identification information of the capacitor.

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